Sample records for amazonian forests implications
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NASA Astrophysics Data System (ADS)
Levine, N. M.; Galbraith, D.; Christoffersen, B. J.; Imbuzeiro, H. A.; Restrepo-Coupe, N.; Malhi, Y.; Saleska, S. R.; Costa, M. H.; Phillips, O.; Andrade, A.; Moorcroft, P. R.
2011-12-01
The Amazonian rainforests play a vital role in global water, energy and carbon cycling. The sensitivity of this system to natural and anthropogenic disturbances therefore has important implications for the global climate. Some global models have predicted large-scale forest dieback and the savannization of Amazonia over the next century [Meehl et al., 2007]. While several studies have demonstrated the sensitivity of dynamic global vegetation models to changes in temperature, precipitation, and dry season length [e.g. Galbraith et al., 2010; Good et al., 2011], the ability of these models to accurately reproduce ecosystem dynamics of present-day transitional or low biomass tropical forests has not been demonstrated. A model-data intercomparison was conducted with four state-of-the-art terrestrial ecosystem models to evaluate the ability of these models to accurately represent structure, function, and long-term biomass dynamics over a range of Amazonian ecosystems. Each modeling group conducted a series of simulations for 14 sites including mature forest, transitional forest, savannah, and agricultural/pasture sites. All models were run using standard physical parameters and the same initialization procedure. Model results were compared against forest inventory and dendrometer data in addition to flux tower measurements. While the models compared well against field observations for the mature forest sites, significant differences were observed between predicted and measured ecosystem structure and dynamics for the transitional forest and savannah sites. The length of the dry season and soil sand content were good predictors of model performance. In addition, for the big leaf models, model performance was highest for sites dominated by late successional trees and lowest for sites with predominantly early and mid-successional trees. This study provides insight into tropical forest function and sensitivity to environmental conditions that will aid in predictions of the response of the Amazonian rainforest to future anthropogenically induced changes.
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Jared D. Wolfe; Philip C. Stouffer; Karl Mokross; Luke L. Powell; Marina M. Anciães
2015-01-01
Avian diversity in fragmented Amazonian landscapes depends on a balance between extinction and colonization in cleared and disturbed areas. Regenerating forest facilitates bird dispersal within degraded Amazonian landscapes and may tip the balance in favor of persistence in habitat patches. Determining the response of Amazonian birds to fragmentation may be...
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Climate change, deforestation, and the fate of the Amazon.
Malhi, Yadvinder; Roberts, J Timmons; Betts, Richard A; Killeen, Timothy J; Li, Wenhong; Nobre, Carlos A
2008-01-11
The forest biome of Amazonia is one of Earth's greatest biological treasures and a major component of the Earth system. This century, it faces the dual threats of deforestation and stress from climate change. Here, we summarize some of the latest findings and thinking on these threats, explore the consequences for the forest ecosystem and its human residents, and outline options for the future of Amazonia. We also discuss the implications of new proposals to finance preservation of Amazonian forests.
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Ancient human disturbances may be skewing our understanding of Amazonian forests.
McMichael, Crystal N H; Matthews-Bird, Frazer; Farfan-Rios, William; Feeley, Kenneth J
2017-01-17
Although the Amazon rainforest houses much of Earth's biodiversity and plays a major role in the global carbon budget, estimates of tree biodiversity originate from fewer than 1,000 forest inventory plots, and estimates of carbon dynamics are derived from fewer than 200 recensus plots. It is well documented that the pre-European inhabitants of Amazonia actively transformed and modified the forest in many regions before their population collapse around 1491 AD; however, the impacts of these ancient disturbances remain entirely unaccounted for in the many highly influential studies using Amazonian forest plots. Here we examine whether Amazonian forest inventory plot locations are spatially biased toward areas with high probability of ancient human impacts. Our analyses reveal that forest inventory plots, and especially forest recensus plots, in all regions of Amazonia are located disproportionately near archaeological evidence and in areas likely to have ancient human impacts. Furthermore, regions of the Amazon that are relatively oversampled with inventory plots also contain the highest values of predicted ancient human impacts. Given the long lifespan of Amazonian trees, many forest inventory and recensus sites may still be recovering from past disturbances, potentially skewing our interpretations of forest dynamics and our understanding of how these forests are responding to global change. Empirical data on the human history of forest inventory sites are crucial for determining how past disturbances affect modern patterns of forest composition and carbon flux in Amazonian forests.
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Ancient human disturbances may be skewing our understanding of Amazonian forests
McMichael, Crystal N. H.; Matthews-Bird, Frazer; Farfan-Rios, William; Feeley, Kenneth J.
2017-01-01
Although the Amazon rainforest houses much of Earth’s biodiversity and plays a major role in the global carbon budget, estimates of tree biodiversity originate from fewer than 1,000 forest inventory plots, and estimates of carbon dynamics are derived from fewer than 200 recensus plots. It is well documented that the pre-European inhabitants of Amazonia actively transformed and modified the forest in many regions before their population collapse around 1491 AD; however, the impacts of these ancient disturbances remain entirely unaccounted for in the many highly influential studies using Amazonian forest plots. Here we examine whether Amazonian forest inventory plot locations are spatially biased toward areas with high probability of ancient human impacts. Our analyses reveal that forest inventory plots, and especially forest recensus plots, in all regions of Amazonia are located disproportionately near archaeological evidence and in areas likely to have ancient human impacts. Furthermore, regions of the Amazon that are relatively oversampled with inventory plots also contain the highest values of predicted ancient human impacts. Given the long lifespan of Amazonian trees, many forest inventory and recensus sites may still be recovering from past disturbances, potentially skewing our interpretations of forest dynamics and our understanding of how these forests are responding to global change. Empirical data on the human history of forest inventory sites are crucial for determining how past disturbances affect modern patterns of forest composition and carbon flux in Amazonian forests. PMID:28049821
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Tall Amazonian forests are less sensitive to precipitation variability
NASA Astrophysics Data System (ADS)
Giardina, Francesco; Konings, Alexandra G.; Kennedy, Daniel; Alemohammad, Seyed Hamed; Oliveira, Rafael S.; Uriarte, Maria; Gentine, Pierre
2018-06-01
Climate change is altering the dynamics, structure and function of the Amazon, a biome deeply connected to the Earth's carbon cycle. Climate factors that control the spatial and temporal variations in forest photosynthesis have been well studied, but the influence of forest height and age on this controlling effect has rarely been considered. Here, we present remote sensing observations of solar-induced fluorescence (a proxy for photosynthesis), precipitation, vapour-pressure deficit and canopy height, together with estimates of forest age and aboveground biomass. We show that photosynthesis in tall Amazonian forests, that is, forests above 30 m, is three times less sensitive to precipitation variability than in shorter (less than 20 m) forests. Taller Amazonian forests are also found to be older, have more biomass and deeper rooting systems1, which enable them to access deeper soil moisture and make them more resilient to drought. We suggest that forest height and age are an important control of photosynthesis in response to interannual precipitation fluctuations. Although older and taller trees show less sensitivity to precipitation variations, they are more susceptible to fluctuations in vapour-pressure deficit. Our findings illuminate the response of Amazonian forests to water stress, droughts and climate change.
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Dispersal assembly of rain forest tree communities across the Amazon basin
Lavin, Mathew; Torke, Benjamin M.; Twyford, Alex D.; Kursar, Thomas A.; Coley, Phyllis D.; Drake, Camila; Hollands, Ruth; Pennington, R. Toby
2017-01-01
We investigate patterns of historical assembly of tree communities across Amazonia using a newly developed phylogeny for the species-rich neotropical tree genus Inga. We compare our results with those for three other ecologically important, diverse, and abundant Amazonian tree lineages, Swartzia, Protieae, and Guatteria. Our analyses using phylogenetic diversity metrics demonstrate a clear lack of geographic phylogenetic structure, and show that local communities of Inga and regional communities of all four lineages are assembled by dispersal across Amazonia. The importance of dispersal in the biogeography of Inga and other tree genera in Amazonian and Guianan rain forests suggests that speciation is not driven by vicariance, and that allopatric isolation following dispersal may be involved in the speciation process. A clear implication of these results is that over evolutionary timescales, the metacommunity for any local or regional tree community in the Amazon is the entire Amazon basin. PMID:28213498
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Dispersal assembly of rain forest tree communities across the Amazon basin.
Dexter, Kyle G; Lavin, Mathew; Torke, Benjamin M; Twyford, Alex D; Kursar, Thomas A; Coley, Phyllis D; Drake, Camila; Hollands, Ruth; Pennington, R Toby
2017-03-07
We investigate patterns of historical assembly of tree communities across Amazonia using a newly developed phylogeny for the species-rich neotropical tree genus Inga We compare our results with those for three other ecologically important, diverse, and abundant Amazonian tree lineages, Swartzia , Protieae, and Guatteria Our analyses using phylogenetic diversity metrics demonstrate a clear lack of geographic phylogenetic structure, and show that local communities of Inga and regional communities of all four lineages are assembled by dispersal across Amazonia. The importance of dispersal in the biogeography of Inga and other tree genera in Amazonian and Guianan rain forests suggests that speciation is not driven by vicariance, and that allopatric isolation following dispersal may be involved in the speciation process. A clear implication of these results is that over evolutionary timescales, the metacommunity for any local or regional tree community in the Amazon is the entire Amazon basin.
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Anthropogenic Land-use Change and the Dynamics of Amazon Forest Biomass
NASA Technical Reports Server (NTRS)
Laurance, William F.
2004-01-01
This project was focused on assessing the effects of prevailing land uses, such as habitat fragmentation, selective logging, and fire, on biomass and carbon storage in Amazonian forests, and on the dynamics of carbon sequestration in regenerating forests. Ancillary goals included developing GIs models to help predict the future condition of Amazonian forests, and assessing the effects of anthropogenic climate change and ENS0 droughts on intact and fragmented forests. Ground-based studies using networks of permanent plots were linked with remote-sensing data (including Landsat TM and AVHRR) at regional scales, and higher-resolution techniques (IKONOS imagery, videography, LIDAR, aerial photographs) at landscape and local scales. The project s specific goals were quite eclectic and included: Determining the effects of habitat fragmentation on forest dynamics, floristic composition, and the various components of above- and below-ground biomass. Assessing historical and physical factors that affect trajectories of forest regeneration and carbon sequestration on abandoned lands. Extrapolating results from local studies of biomass dynamics in fragmented and regenerating forests to landscape and regional scales in Amazonia, using remote sensing and GIS. Testing the hypothesis that intact Amazonian forests are functioning as a significant carbon sink. Examining destructive synergisms between forest fragmentation and fire. Assessing the short-term impacts of selective logging on aboveground biomass. Developing GIS models that integrate current spatial data on forest cover, deforestation, logging, mining, highway and roads, navigable rivers, vulnerability to wild fires, protected areas, and existing and planned infrastructure projects, in an effort to predict the future condition of Brazilian Amazonian forests over the next 20-25 years. Devising predictive spatial models to assess the influence of varied biophysical and anthropogenic predictors on Amazonian deforestation.
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Changes in Amazonian forest biomass, dynamics, and composition, 1980-2002
NASA Astrophysics Data System (ADS)
Phillips, Oliver L.; Higuchi, Niro; Vieira, Simone; Baker, Timothy R.; Chao, Kuo-Jung; Lewis, Simon L.
Long-term, on-the-ground monitoring of forest plots distributed across Amazonia provides a powerful means to quantify stocks and fluxes of biomass and biodiversity. Here we examine the evidence for concerted changes in the structure, dynamics, and functional composition of old-growth Amazonian forests over recent decades. Mature forests have, as a whole, gained biomass and undergone accelerated growth and dynamics, but questions remain as to the long-term persistence of these changes. Because forest growth on average exceeds mortality, intact Amazonian forests have been functioning as a carbon sink. We estimate a net biomass increase in trees ≥10 cm diameter of 0.62 ± 0.23 t C ha-1 a-1 through the late twentieth century. If representative of the wider forest landscape, this translates into a sink in South American old-growth forest of at least 0.49 ± 0.18 Pg C a-1. If other biomass and necromass components also increased proportionally, the estimated South American old-growth forest sink is 0.79 ± 0.29 Pg C a-1, before allowing for possible gains in soil carbon. If tropical forests elsewhere are behaving similarly, the old-growth biomass forest sink would be 1.60 ± 0.58 Pg C a-1. This bottom-up estimate of the carbon balance of tropical forests is preliminary, pending syntheses of detailed biometric studies across the other tropical continents. There is also some evidence for recent changes in the functional composition (biodiversity) of Amazonian forest, but the evidence is less comprehensive than that for changes in structure and dynamics. The most likely driver(s) of changes are recent increases in the supply of resources such as atmospheric carbon dioxide, which would increase net primary productivity, increasing tree growth and recruitment, and, in turn, mortality. In the future the growth response of remaining undisturbed Amazonian forests is likely to saturate, and there is a risk of these ecosystems transitioning from sink to source driven by higher respiration (temperature), higher mortality (drought), or compositional change (functional shifts toward lighterwooded plants). Even a modest switch from carbon sink to source for Amazonian forests would impact global climate, biodiversity, and human welfare, while the documented acceleration of tree growth and mortality may already be affecting the interactions of thousands of plant and millions of animal species.
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Steven J. Presley; Michael R. Willig; Wunderle Jr. Joseph M.; Luis Nélio Saldanha
2008-01-01
1.As human population size increases, demand for natural resources will increase. Logging pressure related to increasing demands continues to threaten remote areas of Amazonian forest. A harvest protocol is required to provide renewable timber resources that meet consumer needs while minimizing negative effects on biodiversity and ecosystem services. Reduced-impact...
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Forest turnover rates follow global and regional patterns of productivity
Stephenson, N.L.; van Mantgem, P.J.
2005-01-01
Using a global database, we found that forest turnover rates (the average of tree mortality and recruitment rates) parallel broad-scale patterns of net primary productivity. First, forest turnover was higher in tropical than in temperate forests. Second, as recently demonstrated by others, Amazonian forest turnover was higher on fertile than infertile soils. Third, within temperate latitudes, turnover was highest in angiosperm forests, intermediate in mixed forests, and lowest in gymnosperm forests. Finally, within a single forest physiognomic type, turnover declined sharply with elevation (hence with temperature). These patterns of turnover in populations of trees are broadly similar to the patterns of turnover in populations of plant organs (leaves and roots) found in other studies. Our findings suggest a link between forest mass balance and the population dynamics of trees, and have implications for understanding and predicting the effects of environmental changes on forest structure and terrestrial carbon dynamics. ??2005 Blackwell Publishing Ltd/CNRS.
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Wüster, Wolfgang; Ferguson, Julia E; Quijada-Mascareñas, J Adrian; Pook, Catharine E; Salomão, Maria da Graça; Thorpe, Roger S
2005-04-01
Abstract Pleistocene fragmentation of the Amazonian rainforest has been hypothesized to be a major cause of Neotropical speciation and diversity. However, the role and even the reality of Pleistocene forest refugia have attracted much scepticism. In Amazonia, previous phylogeographical studies have focused mostly on organisms found in the forests themselves, and generally found speciation events to have predated the Pleistocene. However, molecular studies of open-formation taxa found both north and south of the Amazonian forests, probably because of vicariance resulting from expansion of the rainforests, may provide novel insights into the age of continuous forest cover across the Amazon basin. Here, we analyse three mitochondrial genes to infer the phylogeography of one such trans-Amazonian vicariant, the Neotropical rattlesnake (Crotalus durissus), which occupies primarily seasonal formations from Mexico to Argentina, but avoids the rainforests of Central and tropical South America. The phylogeographical pattern is consistent with gradual dispersal along the Central American Isthmus, followed by more rapid dispersal into and across South America after the uplift of the Isthmus of Panama. Low sequence divergence between populations from north and south of the Amazon rainforest is consistent with mid-Pleistocene divergence, approximately 1.1 million years ago (Ma). This suggests that the Amazonian rainforests must have become fragmented or at least shrunk considerably during that period, lending support to the Pleistocene refugia theory as an important cause of distribution patterns, if not necessarily speciation, in Amazonian forest organisms. These results highlight the potential of nonforest species to contribute to an understanding of the history of the Amazonian rainforests themselves.
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A crisis in the making: responses of Amazonian forests to land use and climate change.
Laurance, W F
1998-10-01
At least three global-change phenomena are having major impacts on Amazonian forests: (1) accelerating deforestation and logging; (2) rapidly changing patterns of forest loss; and (3) interactions between human land-use and climatic variability. Additional alterations caused by climatic change, rising concentrations of atmospheric carbon dioxide, mining, overhunting and other large-scale phenomena could also have important effects on the Amazon ecosystem. Consequently, decisions regarding Amazon forest use in the next decade are crucial to its future existence.
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Deforestation and stream warming affect body size of Amazonian fishes.
Ilha, Paulo; Schiesari, Luis; Yanagawa, Fernando I; Jankowski, KathiJo; Navas, Carlos A
2018-01-01
Declining body size has been suggested to be a universal response of organisms to rising temperatures, manifesting at all levels of organization and in a broad range of taxa. However, no study to date evaluated whether deforestation-driven warming could trigger a similar response. We studied changes in fish body size, from individuals to assemblages, in streams in Southeastern Amazonia. We first conducted sampling surveys to validate the assumption that deforestation promoted stream warming, and to test the hypothesis that warmer deforested streams had reduced fish body sizes relative to cooler forest streams. As predicted, deforested streams were up to 6 °C warmer and had fish 36% smaller than forest streams on average. This body size reduction could be largely explained by the responses of the four most common species, which were 43-55% smaller in deforested streams. We then conducted a laboratory experiment to test the hypothesis that stream warming as measured in the field was sufficient to cause a growth reduction in the dominant fish species in the region. Fish reared at forest stream temperatures gained mass, whereas those reared at deforested stream temperatures lost mass. Our results suggest that deforestation-driven stream warming is likely to be a relevant factor promoting observed body size reductions, although other changes in stream conditions, like reductions in organic matter inputs, can also be important. A broad scale reduction in fish body size due to warming may be occurring in streams throughout the Amazonian Arc of Deforestation, with potential implications for the conservation of Amazonian fish biodiversity and food supply for people around the Basin.
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Deforestation and stream warming affect body size of Amazonian fishes
Yanagawa, Fernando I.; Jankowski, KathiJo; Navas, Carlos A.
2018-01-01
Declining body size has been suggested to be a universal response of organisms to rising temperatures, manifesting at all levels of organization and in a broad range of taxa. However, no study to date evaluated whether deforestation-driven warming could trigger a similar response. We studied changes in fish body size, from individuals to assemblages, in streams in Southeastern Amazonia. We first conducted sampling surveys to validate the assumption that deforestation promoted stream warming, and to test the hypothesis that warmer deforested streams had reduced fish body sizes relative to cooler forest streams. As predicted, deforested streams were up to 6 °C warmer and had fish 36% smaller than forest streams on average. This body size reduction could be largely explained by the responses of the four most common species, which were 43–55% smaller in deforested streams. We then conducted a laboratory experiment to test the hypothesis that stream warming as measured in the field was sufficient to cause a growth reduction in the dominant fish species in the region. Fish reared at forest stream temperatures gained mass, whereas those reared at deforested stream temperatures lost mass. Our results suggest that deforestation-driven stream warming is likely to be a relevant factor promoting observed body size reductions, although other changes in stream conditions, like reductions in organic matter inputs, can also be important. A broad scale reduction in fish body size due to warming may be occurring in streams throughout the Amazonian Arc of Deforestation, with potential implications for the conservation of Amazonian fish biodiversity and food supply for people around the Basin. PMID:29718960
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J. Barlow; C. A. Peres; L. M. P. Henr¡ques; P. C. Stouffer; J. M. Wunderle
2006-01-01
We combine mist-net data from 24 disturbance treatments taken from seven studies on the responses of understorey Amazonian birds to selective logging, single and recurrent wildfires, and habitat fragmentation. The different disturbance treatments had distinct effects on avian guild structure, and fire disturbance and the isolation of forest patches resulted in bird...
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Protecting biodiversity in situ in the Amazonian Region of Brazil
Claudia Sellier
2007-01-01
Brazil has approximately 3.6 million km2 (1.4 million mi2) of forest, with the majority concentrated in the Amazonian region. The Atlantic Forest was reduced to less than 8 percent of its original territory. Development activities are being implemented without consideration for the local environment, causing both biodiversity and habitat losses. Establishment of...
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Capurucho, João Marcos Guimarães; Ashley, Mary V; Ribas, Camila C; Bates, John M
2018-06-11
Several biogeographic hypotheses have been proposed to explain connections between Amazonian and Atlantic forest biotas. These hypotheses are related to the timing of the connections and their geographic patterns. We performed a phylogeographic investigation of Tyrant-manakins (Aves: Pipridae, Neopelma/Tyranneutes) which include species inhabiting the Amazon and Atlantic forests, as well as gallery forests of the Cerrado. Using DNA sequence data, we determined phylogenetic relationships, temporal and geographic patterns of diversification, and recent intraspecific population genetic patterns, relative to the history of these biomes. We found Neopelma to be a paraphyletic genus, as N. chrysolophum is sister to Neopelma + Tyranneutes, with an estimated divergence of approximately 18 Myrs BP, within the oldest estimated divergence times of other Amazonian and Atlantic forest avian taxa. Subsequent divergences in the group occurred from Mid Miocene to Early Pliocene and involved mainly the Amazonian species, with an expansion into and subsequent speciation in the Cerrado gallery forests by N. pallescens. We found additional structure within N. chrysocephalum and N. sulphureiventer. Analysis of recent population dynamics in N. chrysocephalum, N. sulphureiventer, and N. pallescens revealed recent demographic fluctuations and restrictions to gene flow related to environmental changes since the last glacial cycle. No genetic structure was detected across the Amazon River in N. pallescens. The tyrant-manakins represent an old historical connection between the Amazon and Atlantic Forest. Copyright © 2018. Published by Elsevier Inc.
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NASA Astrophysics Data System (ADS)
Betts, R. A.; Cox, P. M.; Collins, M.; Harris, P. P.; Huntingford, C.; Jones, C. D.
A suite of simulations with the HadCM3LC coupled climate-carbon cycle model is used to examine the various forcings and feedbacks involved in the simulated precipitation decrease and forest dieback. Rising atmospheric CO2 is found to contribute 20% to the precipitation reduction through the physiological forcing of stomatal closure, with 80% of the reduction being seen when stomatal closure was excluded and only radiative forcing by CO2 was included. The forest dieback exerts two positive feedbacks on the precipitation reduction; a biogeophysical feedback through reduced forest cover suppressing local evaporative water recycling, and a biogeochemical feedback through the release of CO2 contributing to an accelerated global warming. The precipitation reduction is enhanced by 20% by the biogeophysical feedback, and 5% by the carbon cycle feedback from the forest dieback. This analysis helps to explain why the Amazonian precipitation reduction simulated by HadCM3LC is more extreme than that simulated in other GCMs; in the fully-coupled, climate-carbon cycle simulation, approximately half of the precipitation reduction in Amazonia is attributable to a combination of physiological forcing and biogeophysical and global carbon cycle feedbacks, which are generally not included in other GCM simulations of future climate change. The analysis also demonstrates the potential contribution of regional-scale climate and ecosystem change to uncertainties in global CO2 and climate change projections. Moreover, the importance of feedbacks suggests that a human-induced increase in forest vulnerability to climate change may have implications for regional and global scale climate sensitivity.
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Baker, Timothy R; Vela Díaz, Dilys M; Chama Moscoso, Victor; Navarro, Gilberto; Monteagudo, Abel; Pinto, Ruy; Cangani, Katia; Fyllas, Nikolaos M; Lopez Gonzalez, Gabriela; Laurance, William F; Lewis, Simon L; Lloyd, Jonathan; Ter Steege, Hans; Terborgh, John W; Phillips, Oliver L
2016-03-01
Understanding the resilience of moist tropical forests to treefall disturbance events is important for understanding the mechanisms that underlie species coexistence and for predicting the future composition of these ecosystems. Here, we test whether variation in the functional composition of Amazonian forests determines their resilience to disturbance.We studied the legacy of natural treefall disturbance events in four forests across Amazonia that differ substantially in functional composition. We compared the composition and diversity of all free-standing woody stems 2-10 cm diameter in previously disturbed and undisturbed 20 × 20 m subplots within 55, one-hectare, long-term forest inventory plots.Overall, stem number increased following disturbance, and species and functional composition shifted to favour light-wooded, small-seeded taxa. Alpha-diversity increased, but beta-diversity was unaffected by disturbance, in all four forests.Changes in response to disturbance in both functional composition and alpha-diversity were, however, small (2 - 4% depending on the parameter) and similar among forests. Synthesis . This study demonstrates that variation in the functional composition of Amazonian forests does not lead to large differences in the response of these forests to treefall disturbances, and overall, these events have a minor role in maintaining the diversity of these ecosystems.
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T.G. Soares Neto; J.A. Carvalho J.A.; C.A.G. Veras; E.C. Alvarado; R. Gielow; E.N. Lincoln; T.J. Christian; R.J. Yokelson; J.C. Santos
2009-01-01
Biomass consumption and C02, CO and hydrocarbon gas emissions in an Amazonian forest clearing fire are presented and discussed. The experiment was conducted in the arc of deforestation, near the city of Alta Floresta, state of Mato Grosso, Brazil. The average carbon content of dry biomass was 48 percent and the estimated average moisture content...
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Whendee L. Silver; Jason Neff; Megan McGroddy; Ed Veldkamp; Michael Keller; Raimundo Cosme
2000-01-01
Soil texture plays a key role in belowground C storage in forest ecosystems and strongly influences nutrient availability and retention, particularly in highly weathered soils. We used field data and the Century ecosystem model to explore the role of soil texture in belowground C storage, nutrient pool sizes, and N fluxes in highly weathered soils in an Amazonian...
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NASA Astrophysics Data System (ADS)
Pupim, Fabiano do N.; Sawakushi, André O.; Hartmann, Gelvam A.; Savian, Jairo F.; Kern, Andrea K.; Mineli, Thays D.; Cruz, Francisco W.; Almeida, Renato P.; Grohmann, Carlos H.; Ribas, Camila C.; d'Horta, Fernando M.; Bertassoli, Dailson J.; Marconato, André; Nogueira, Luciana; Lohmann, Lúcia G.
2017-04-01
The shift from a large wetland dominated by avulsive channels and flooded forests to the incised transcontinental Amazon River valley (Várzea) bounded by non-flooded forests (Terra Firme) is suggested as one of the main drivers of diversification of the mega diverse Amazonian Biota. Nonetheless, there is no consensus about the timing of this landscape shift, with the current literature suggesting a period that ranges from the Miocene (11 Ma) and the Late Pleistocene (100 ka). This uncertainty may be due to a lack of absolute ages for the sediments forming Terra Firme forest substrates in western Amazonian lowlands. In Brazil, the Içá Formation represents the uppermost fluvial deposits of Terra Firme forests substrates in western Amazonia. Therefore, a reliable chronology for the last depositional stage of the Içá Formation is key for an improved understanding of the formation of the current Terra Firme-Várzea system. Four sediment profiles were sampled along the margins of the Solimões and Içá rivers for Optically Stimulated Luminescence (OSL) dating, geomagnetic excursions, and palynological analysis. OSL dating was performed in twelve samples using a Single Aliquot Regeneration (SAR) protocol in quartz sand grains. The equivalent doses ranged from 47 to 130 Gy (Central Age Model) and the dose rate values ranged from 0.4 to 2.0 Gy/ka. The resulting sediment burial ages range from 48 to 112 ka. Paleomagnetic data were obtained from samples collected at same profiles sampled for OSL dating and results suggest the presence of Post-Blake geomagnetic excursion ( 100 ka). The age of 100 ka for Post-Blake excursion are adopted for the Geomagnetic Instability Time Scale. Pollen assemblage data show a similarity to a more modern flora and the presence of Alnus clearly points towards Pleistocene deposition as it is unknown before in South America. The combined OSL, paleomagnetism and pollen data is a robust geochronological dataset that indicates Late Pleistocene ages for the last stage of built up of the Terra Firme in a broad region of the western Brazilian Amazonian lowlands. Therefore, the present-day unconformity between Terra Firme and Várzea deposits were formed by fluvial incision during the late Pleistocene and Holocene, which seems to be related with precipitation changes in the South American monsoon system. Our geochronological dataset point to important landscape changes during the late Pleistocene, with expansion of non-flooded Terra Firme and retraction of Várzea floodplain forests. This transition probably had important implications for the development of modern phylogeographical and biogeographical patterns in western Amazonia during the Quaternary. Future efforts will focus on dating drill-core sediment records using cosmogenic nuclides to extend the age range. Financial support: FAPESP 2009/53988-8, 2012/50260-6, 2014/23334-4, 2014/09800-2, 2016/09293-9; 2016/02656-9; CNPq 3009223/2014-8, 307647/2015-3; NSF DEB 1241066 and NASA.
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Santos, Bráulio A; Tabarelli, Marcelo; Melo, Felipe P L; Camargo, José L C; Andrade, Ana; Laurance, Susan G; Laurance, William F
2014-01-01
Amazonian rainforests sustain some of the richest tree communities on Earth, but their ecological and evolutionary responses to human threats remain poorly known. We used one of the largest experimental datasets currently available on tree dynamics in fragmented tropical forests and a recent phylogeny of angiosperms to test whether tree communities have lost phylogenetic diversity since their isolation about two decades previously. Our findings revealed an overall trend toward phylogenetic impoverishment across the experimentally fragmented landscape, irrespective of whether tree communities were in 1-ha, 10-ha, or 100-ha forest fragments, near forest edges, or in continuous forest. The magnitude of the phylogenetic diversity loss was low (<2% relative to before-fragmentation values) but widespread throughout the study landscape, occurring in 32 of 40 1-ha plots. Consistent with this loss in phylogenetic diversity, we observed a significant decrease of 50% in phylogenetic dispersion since forest isolation, irrespective of plot location. Analyses based on tree genera that have significantly increased (28 genera) or declined (31 genera) in abundance and basal area in the landscape revealed that increasing genera are more phylogenetically related than decreasing ones. Also, the loss of phylogenetic diversity was greater in tree communities where increasing genera proliferated and decreasing genera reduced their importance values, suggesting that this taxonomic replacement is partially underlying the phylogenetic impoverishment at the landscape scale. This finding has clear implications for the current debate about the role human-modified landscapes play in sustaining biodiversity persistence and key ecosystem services, such as carbon storage. Although the generalization of our findings to other fragmented tropical forests is uncertain, it could negatively affect ecosystem productivity and stability and have broader impacts on coevolved organisms.
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T. G. Soares Neto; J. A. Carvalho; C. A. G. Veras; E. C. Alvarado; R. Gielow; E. N. Lincoln; T. J. Christian; R. J. Yokelson; J. C. Santos
2009-01-01
Biomass consumption and CO2, CO and hydrocarbon gas emissions in an Amazonian forest clearing fire are presented and discussed. The experiment was conducted in the arc of deforestation, near the city of Alta Floresta, state of Mato Grosso, Brazil. The average carbon content of dry biomass was 48% and the estimated average moisture content of fresh biomass was 42% on...
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Hyperdominance in Amazonian forest carbon cycling
Fauset, Sophie; Johnson, Michelle O.; Gloor, Manuel; Baker, Timothy R.; Monteagudo M., Abel; Brienen, Roel J.W.; Feldpausch, Ted R.; Lopez-Gonzalez, Gabriela; Malhi, Yadvinder; ter Steege, Hans; Pitman, Nigel C.A.; Baraloto, Christopher; Engel, Julien; Pétronelli, Pascal; Andrade, Ana; Camargo, José Luís C.; Laurance, Susan G.W.; Laurance, William F.; Chave, Jerôme; Allie, Elodie; Vargas, Percy Núñez; Terborgh, John W.; Ruokolainen, Kalle; Silveira, Marcos; Aymard C., Gerardo A.; Arroyo, Luzmila; Bonal, Damien; Ramirez-Angulo, Hirma; Araujo-Murakami, Alejandro; Neill, David; Hérault, Bruno; Dourdain, Aurélie; Torres-Lezama, Armando; Marimon, Beatriz S.; Salomão, Rafael P.; Comiskey, James A.; Réjou-Méchain, Maxime; Toledo, Marisol; Licona, Juan Carlos; Alarcón, Alfredo; Prieto, Adriana; Rudas, Agustín; van der Meer, Peter J.; Killeen, Timothy J.; Marimon Junior, Ben-Hur; Poorter, Lourens; Boot, Rene G.A.; Stergios, Basil; Torre, Emilio Vilanova; Costa, Flávia R.C.; Levis, Carolina; Schietti, Juliana; Souza, Priscila; Groot, Nikée; Arets, Eric; Moscoso, Victor Chama; Castro, Wendeson; Coronado, Euridice N. Honorio; Peña-Claros, Marielos; Stahl, Clement; Barroso, Jorcely; Talbot, Joey; Vieira, Ima Célia Guimarães; van der Heijden, Geertje; Thomas, Raquel; Vos, Vincent A.; Almeida, Everton C.; Davila, Esteban Álvarez; Aragão, Luiz E.O.C.; Erwin, Terry L.; Morandi, Paulo S.; de Oliveira, Edmar Almeida; Valadão, Marco B.X.; Zagt, Roderick J.; van der Hout, Peter; Loayza, Patricia Alvarez; Pipoly, John J.; Wang, Ophelia; Alexiades, Miguel; Cerón, Carlos E.; Huamantupa-Chuquimaco, Isau; Di Fiore, Anthony; Peacock, Julie; Camacho, Nadir C. Pallqui; Umetsu, Ricardo K.; de Camargo, Plínio Barbosa; Burnham, Robyn J.; Herrera, Rafael; Quesada, Carlos A.; Stropp, Juliana; Vieira, Simone A.; Steininger, Marc; Rodríguez, Carlos Reynel; Restrepo, Zorayda; Muelbert, Adriane Esquivel; Lewis, Simon L.; Pickavance, Georgia C.; Phillips, Oliver L.
2015-01-01
While Amazonian forests are extraordinarily diverse, the abundance of trees is skewed strongly towards relatively few ‘hyperdominant' species. In addition to their diversity, Amazonian trees are a key component of the global carbon cycle, assimilating and storing more carbon than any other ecosystem on Earth. Here we ask, using a unique data set of 530 forest plots, if the functions of storing and producing woody carbon are concentrated in a small number of tree species, whether the most abundant species also dominate carbon cycling, and whether dominant species are characterized by specific functional traits. We find that dominance of forest function is even more concentrated in a few species than is dominance of tree abundance, with only ≈1% of Amazon tree species responsible for 50% of carbon storage and productivity. Although those species that contribute most to biomass and productivity are often abundant, species maximum size is also influential, while the identity and ranking of dominant species varies by function and by region. PMID:25919449
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Hyperdominance in Amazonian forest carbon cycling.
Fauset, Sophie; Johnson, Michelle O; Gloor, Manuel; Baker, Timothy R; Monteagudo M, Abel; Brienen, Roel J W; Feldpausch, Ted R; Lopez-Gonzalez, Gabriela; Malhi, Yadvinder; ter Steege, Hans; Pitman, Nigel C A; Baraloto, Christopher; Engel, Julien; Pétronelli, Pascal; Andrade, Ana; Camargo, José Luís C; Laurance, Susan G W; Laurance, William F; Chave, Jerôme; Allie, Elodie; Vargas, Percy Núñez; Terborgh, John W; Ruokolainen, Kalle; Silveira, Marcos; Aymard C, Gerardo A; Arroyo, Luzmila; Bonal, Damien; Ramirez-Angulo, Hirma; Araujo-Murakami, Alejandro; Neill, David; Hérault, Bruno; Dourdain, Aurélie; Torres-Lezama, Armando; Marimon, Beatriz S; Salomão, Rafael P; Comiskey, James A; Réjou-Méchain, Maxime; Toledo, Marisol; Licona, Juan Carlos; Alarcón, Alfredo; Prieto, Adriana; Rudas, Agustín; van der Meer, Peter J; Killeen, Timothy J; Marimon Junior, Ben-Hur; Poorter, Lourens; Boot, Rene G A; Stergios, Basil; Torre, Emilio Vilanova; Costa, Flávia R C; Levis, Carolina; Schietti, Juliana; Souza, Priscila; Groot, Nikée; Arets, Eric; Moscoso, Victor Chama; Castro, Wendeson; Coronado, Euridice N Honorio; Peña-Claros, Marielos; Stahl, Clement; Barroso, Jorcely; Talbot, Joey; Vieira, Ima Célia Guimarães; van der Heijden, Geertje; Thomas, Raquel; Vos, Vincent A; Almeida, Everton C; Davila, Esteban Álvarez; Aragão, Luiz E O C; Erwin, Terry L; Morandi, Paulo S; de Oliveira, Edmar Almeida; Valadão, Marco B X; Zagt, Roderick J; van der Hout, Peter; Loayza, Patricia Alvarez; Pipoly, John J; Wang, Ophelia; Alexiades, Miguel; Cerón, Carlos E; Huamantupa-Chuquimaco, Isau; Di Fiore, Anthony; Peacock, Julie; Camacho, Nadir C Pallqui; Umetsu, Ricardo K; de Camargo, Plínio Barbosa; Burnham, Robyn J; Herrera, Rafael; Quesada, Carlos A; Stropp, Juliana; Vieira, Simone A; Steininger, Marc; Rodríguez, Carlos Reynel; Restrepo, Zorayda; Muelbert, Adriane Esquivel; Lewis, Simon L; Pickavance, Georgia C; Phillips, Oliver L
2015-04-28
While Amazonian forests are extraordinarily diverse, the abundance of trees is skewed strongly towards relatively few 'hyperdominant' species. In addition to their diversity, Amazonian trees are a key component of the global carbon cycle, assimilating and storing more carbon than any other ecosystem on Earth. Here we ask, using a unique data set of 530 forest plots, if the functions of storing and producing woody carbon are concentrated in a small number of tree species, whether the most abundant species also dominate carbon cycling, and whether dominant species are characterized by specific functional traits. We find that dominance of forest function is even more concentrated in a few species than is dominance of tree abundance, with only ≈1% of Amazon tree species responsible for 50% of carbon storage and productivity. Although those species that contribute most to biomass and productivity are often abundant, species maximum size is also influential, while the identity and ranking of dominant species varies by function and by region.
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Studying the Effects of Amazonian Land Cover Change on Glacier Mass Balance in the Tropical Andes
NASA Astrophysics Data System (ADS)
Mark, B. G.; Fernandez, A.; Gabrielli, P.; Montenegro, A.; Postigo, J.; Hellstrom, R. A.
2017-12-01
Recent research has highlighted several ongoing environmental changes occurring across Tropical South America, including Andean glacier retreat, drought, as well as changes in land-use and land-cover. As the regional climate of the area is mostly characterized by land-ocean interactions, the atmospheric convection in the Amazon, and the effect of the Andes on circulation patterns, it follows that changes in one of those regions may affect the other. Most scholars who have studied the causes of tropical glaciers' fluctuations have not analyzed the linkages with changes in the Amazon with the same attention paid to the influence of Pacific sea surface temperature. Here we study the response of glacier surface mass balance in the Cordillera Blanca, Peru (10°S), to a scenario where the Amazonian rainforest is replaced by savannas. We ran climatic simulations at 2-km spatial resolution utilizing the Weather Research and Forecasting (WRF) model considering two scenarios: (a) control (CRTL), with today's rainforest extent; and (b) land cover change (LCC), where all the rainforest was replaced by savanna. WRF output was in turn ingested into a glacier energy and mass balance (GEMB) model that we validate by reconstructing both the accumulated mass balance from available observations, and the altitudinal distribution of mass balance in the region. Seasonal comparison between CRTL and LCC scenarios indicates that forest replacement by savanna results in more positive glacier mass balance. This shift to more positive mass balance contrasts with a (WRF) modeled rise in the elevation of the freezing line (0°C) between 30 to 120 m for the LCC scenario. Our results are surprising because most previous studies have shown that reducing Amazon forest cover diminishes rainfall and increases temperature, suggesting that glaciers should lose mass. We hypothesize and discuss implications of possible land-atmospheric processes that might drive this tropical glacier response to Amazonian forest change, including: the large-scale influence of Amazonian albedo change on the interaction between the Walker and Hadley cells and the effect of mountain meteorology dynamics.
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Model gives a 3-month warning of Amazonian forest fires
NASA Astrophysics Data System (ADS)
Schultz, Colin
2011-08-01
The widespread drought suffered by the Amazon rain forest in the summer of 2005 was heralded at the time as the drought of the century. Because of the dehydrated conditions, supplemented by slash and burn agricultural practices, the drought led to widespread forest fires throughout the western Amazon, a portion of the rain forest usually too lush to support spreading wildfires. Only 5 years later, the 2005 season was outdone by even more widespread drought, with fires decimating more than 3000 square kilometers of western Amazonian rain forest. Blame for the wildfires has been consistently laid on deforestation and agricultural practices, but a convincing climatological explanation exists as well. (Geophysical Research Letters, doi:10.1029/2011GL047392, 2011)
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An Amazonian rainforest and its fragments as a laboratory of global change.
Laurance, William F; Camargo, José L C; Fearnside, Philip M; Lovejoy, Thomas E; Williamson, G Bruce; Mesquita, Rita C G; Meyer, Christoph F J; Bobrowiec, Paulo E D; Laurance, Susan G W
2018-02-01
We synthesize findings from one of the world's largest and longest-running experimental investigations, the Biological Dynamics of Forest Fragments Project (BDFFP). Spanning an area of ∼1000 km 2 in central Amazonia, the BDFFP was initially designed to evaluate the effects of fragment area on rainforest biodiversity and ecological processes. However, over its 38-year history to date the project has far transcended its original mission, and now focuses more broadly on landscape dynamics, forest regeneration, regional- and global-change phenomena, and their potential interactions and implications for Amazonian forest conservation. The project has yielded a wealth of insights into the ecological and environmental changes in fragmented forests. For instance, many rainforest species are naturally rare and hence are either missing entirely from many fragments or so sparsely represented as to have little chance of long-term survival. Additionally, edge effects are a prominent driver of fragment dynamics, strongly affecting forest microclimate, tree mortality, carbon storage and a diversity of fauna. Even within our controlled study area, the landscape has been highly dynamic: for example, the matrix of vegetation surrounding fragments has changed markedly over time, succeeding from large cattle pastures or forest clearcuts to secondary regrowth forest. This, in turn, has influenced the dynamics of plant and animal communities and their trajectories of change over time. In general, fauna and flora have responded differently to fragmentation: the most locally extinction-prone animal species are those that have both large area requirements and low tolerance of the modified habitats surrounding fragments, whereas the most vulnerable plants are those that respond poorly to edge effects or chronic forest disturbances, and that rely on vulnerable animals for seed dispersal or pollination. Relative to intact forests, most fragments are hyperdynamic, with unstable or fluctuating populations of species in response to a variety of external vicissitudes. Rare weather events such as droughts, windstorms and floods have had strong impacts on fragments and left lasting legacies of change. Both forest fragments and the intact forests in our study area appear to be influenced by larger-scale environmental drivers operating at regional or global scales. These drivers are apparently increasing forest productivity and have led to concerted, widespread increases in forest dynamics and plant growth, shifts in tree-community composition, and increases in liana (woody vine) abundance. Such large-scale drivers are likely to interact synergistically with habitat fragmentation, exacerbating its effects for some species and ecological phenomena. Hence, the impacts of fragmentation on Amazonian biodiversity and ecosystem processes appear to be a consequence not only of local site features but also of broader changes occurring at landscape, regional and even global scales. © 2017 Cambridge Philosophical Society.
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Pervasive Rise of Small-scale Deforestation in Amazonia.
Kalamandeen, Michelle; Gloor, Emanuel; Mitchard, Edward; Quincey, Duncan; Ziv, Guy; Spracklen, Dominick; Spracklen, Benedict; Adami, Marcos; Aragão, Luiz E O C; Galbraith, David
2018-01-25
Understanding forest loss patterns in Amazonia, the Earth's largest rainforest region, is critical for effective forest conservation and management. Following the most detailed analysis to date, spanning the entire Amazon and extending over a 14-year period (2001-2014), we reveal significant shifts in deforestation dynamics of Amazonian forests. Firstly, hotspots of Amazonian forest loss are moving away from the southern Brazilian Amazon to Peru and Bolivia. Secondly, while the number of new large forest clearings (>50 ha) has declined significantly over time (46%), the number of new small clearings (<1 ha) increased by 34% between 2001-2007 and 2008-2014. Thirdly, we find that small-scale low-density forest loss expanded markedly in geographical extent during 2008-2014. This shift presents an important and alarming new challenge for forest conservation, despite reductions in overall deforestation rates.
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Amazonian forest dieback under climate-carbon cycle projections for the 21st century
NASA Astrophysics Data System (ADS)
Cox, P. M.; Betts, R. A.; Collins, M.; Harris, P. P.; Huntingford, C.; Jones, C. D.
The first GCM climate change projections to include dynamic vegetation and an interactive carbon cycle produced a very significant amplification of global warming over the 21st century. Under the IS92a ``business as usual'' emissions scenario CO2 concentrations reached about 980ppmv by 2100, which is about 280ppmv higher than when these feedbacks were ignored. The major contribution to the increased CO2 arose from reductions in soil carbon because global warming is assumed to accelerate respiration. However, there was also a lesser contribution from an alarming loss of the Amazonian rainforest. This paper describes the phenomenon of Amazonian forest dieback under elevated CO2 in the Hadley Centre climate-carbon cycle model.
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Long-term landscape change and bird abundance in Amazonian rainforest fragments.
Stouffer, Philip C; Bierregaard, Richard O; Strong, Cheryl; Lovejoy, Thomas E
2006-08-01
The rainforests of the Amazon basin are being cut by humans at a rate >20,000 km2/year leading to smaller and more isolated patches of forest, with remaining fragments often in the range of 1-100 ha. We analyzed samples of understory birds collected over 20 years from a standardized mist-netting program in 1- to 100-ha rainforest fragments in a dynamic Amazonian landscape near Manaus, Brazil. Across bird guilds, the condition of second growth immediately surrounding fragments was often as important as fragment size or local forest cover in explaining variation in abundance. Some fragments surrounded by 100 m of open pasture showed reductions in insectivorous bird abundance of over 95%, even in landscapes dominated by continuous forest and old second growth. These extreme reductions may be typical throughout Amazonia in small (< or =10 ha), isolated fragments of rainforest. Abundance for some guilds returned to preisolation levels in 10- and 100-ha fragments connected to continuous forest by 20-year-old second growth. Our results show that the consequences of Amazonian forest loss cannot be accurately described without explicit consideration of vegetation dynamics in matrix habitat. Any dichotomous classification of the landscape into 'forest" and "nonforest" misses essential information about the matrix.
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NASA Astrophysics Data System (ADS)
Yan, Hao; Wang, Shao-Qiang; da Rocha, Humberto R.; Rap, Alexandru; Bonal, Damien; Butt, Nathalie; Coupe, Natalia Restrepo; Shugart, Herman H.
2017-11-01
Understanding the mechanism of photosynthetic seasonality in Amazonian evergreen forests is critical for its formulation in global climate and carbon cycle models. However, the control of the unexpected photosynthetic seasonality is highly uncertain. Here we use eddy-covariance data across a network of Amazonian research sites and a novel evapotranspiration (E) and two-leaf-photosynthesis-coupled model to investigate links between photosynthetic seasonality and climate factors on monthly scales. It reproduces the GPP seasonality (R2 = 0.45-0.69) with a root-mean-square error (RMSE) of 0.67-1.25 g C m-2 d-1 and a Bias of -0.03-1.04 g C m-2 d-1 for four evergreen forest sites. We find that the proportion of diffuse and direct sunlight governs the photosynthetic seasonality via their interaction with sunlit and shaded leaves, supported by a proof that canopy light use efficiency (LUE) has a strong linear relationship with the fraction of diffuse sunlight for Amazonian evergreen forests. In the transition from dry season to rainy season, incident total radiation (Q) decreased while LUE and diffuse fraction increased, which produced the large seasonal increase ( 34%) in GPP of evergreen forests. We conclude that diffuse radiation is an important environmental driver of the photosynthetic seasonality in tropical Amazon forests yet depending on light utilization by sunlit and shaded leaves. Besides, the GPP model simulates the precipitation-dominated GPP seasonality (R2 = 0.40-0.69) at pasture and savanna sites. These findings present an improved physiological method to relate light components with GPP in tropical Amazon.
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Using a GCM analogue model to investigate the potential for Amazonian forest dieback
NASA Astrophysics Data System (ADS)
Huntingford, C.; Harris, P. P.; Gedney, N.; Cox, P. M.; Betts, R. A.; Marengo, J. A.; Gash, J. H. C.
A combined GCM analogue model and GCM land surface representation is used to investigate the influences of climatology and land surface parameterisation on modelled Amazonian vegetation change. This modelling structure (called IMOGEN) captures the main features of the changes in surface climate as estimated by a GCM with enhanced atmospheric greenhouse gas concentrations. Advantage is taken of IMOGEN's computational speed which allows multiple simulations to be carried out to assess the robustness of the GCM results. The timing of forest dieback is found to be sensitive to the initial ``pre-industrial'' climate, as well as uncertainties in the representation of land-atmosphere CO2 exchange. Changing from a Q10 form for plant dark and maintanence respiration (as used in the coupled GCM runs) to a respiration proportional to maximum photosynthesis, reduces the biomass lost from Amazonia in the 21st century. Replacing the GCM control climate (which has about 25% too little rain in the annual mean over Amazonia) with an observed climatology increases the CO2 concentration at which rainfall drops to critical levels, and thereby further delays the dieback. On the other hand, calibration of the canopy photosynthesis model against Amazonian flux data tends to lead to earlier forest dieback. Further advances are required in both GCM rainfall simulation and land-surface process representation before a clearer picture will emerge on the timing of possible Amazonian forest dieback. However, it seems likely that these advances will overall lead to projections of later forest dieback as GCM control climates become more realistic.
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Fire-mediated dieback and compositional cascade in an Amazonian forest.
Barlow, Jos; Peres, Carlos A
2008-05-27
The only fully coupled land-atmosphere global climate model predicts a widespread dieback of Amazonian forest cover through reduced precipitation. Although these predictions are controversial, the structural and compositional resilience of Amazonian forests may also have been overestimated, as current vegetation models fail to consider the potential role of fire in the degradation of forest ecosystems. We examine forest structure and composition in the Arapiuns River basin in the central Brazilian Amazon, evaluating post-fire forest recovery and the consequences of recurrent fires for the patterns of dominance of tree species. We surveyed tree plots in unburned and once-burned forests examined 1, 3 and 9 years after an unprecedented fire event, in twice-burned forests examined 3 and 9 years after fire and in thrice-burned forests examined 5 years after the most recent fire event. The number of trees recorded in unburned primary forest control plots was stable over time. However, in both once- and twice-burned forest plots, there was a marked recruitment into the 10-20cm diameter at breast height tree size classes between 3 and 9 years post-fire. Considering tree assemblage composition 9 years after the first fire contact, we observed (i) a clear pattern of community turnover among small trees and the most abundant shrubs and saplings, and (ii) that species that were common in any of the four burn treatments (unburned, once-, twice- and thrice-burned) were often rare or entirely absent in other burn treatments. We conclude that episodic wildfires can lead to drastic changes in forest structure and composition, with cascading shifts in forest composition following each additional fire event. Finally, we use these results to evaluate the validity of the savannization paradigm.
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Vinson, C C; Kanashiro, M; Harris, S A; Boshier, D H
2015-01-01
Selective logging in Brazil allows for the removal of up to 90% of trees above 50 cm diameter of a given timber species, independent of a species' life history characteristics or how quickly it will recover. The genetic and demographic effects of selective logging on two Amazonian timber species (Dipteryx odorata Leguminosae, Jacaranda copaia Bignoniaceae) with contrasting ecological and reproductive characteristics were assessed in the same forest. Genetic diversity and gene flow were characterized by genotyping adults and seed sampled before and after logging, using hypervariable microsatellite markers. Overall, there were no short-term genetic impacts on the J. copaia population, with commercial application of current Brazilian forest management regulations. In contrast, for D. Odorata, selective logging showed a range of genetic impacts, with a 10% loss of alleles, and reductions in siring by pollen from trees within the 546-ha study area (23-11%) and in the number of pollen donors per progeny array (2.8-1.6), illustrating the importance of the surrounding landscape. Asynchrony in flowering between D. odorata trees led to trees with no breeding partners, which could limit the species reproduction and regeneration under current regulations. The results are summarized with other published studies from the same site and the implications for forest management discussed. The different types and levels of impacts associated with each species support the idea that ecological and genetic information by species, ecological guild or reproductive group is essential in helping to derive sustainable logging guidelines for tropical forests. © 2014 John Wiley & Sons Ltd.
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Reduced Future Precipitation Makes Permanence of Amazonian Carbon Sinks Questionable
NASA Astrophysics Data System (ADS)
Arora, V.
2011-12-01
The tropical forests of the Amazon, considered as a tipping element in Earth's climate system, provide several ecosystem services including the maintenance of favourable regional climatic conditions in the region and storage of large amounts of carbon in their above- and below-ground pools. While it is nearly impossible, at present, to put a dollar value on these ecosystem services, the developed countries have started paying large sums of money to developing countries in the tropics to reduce deforestation. Norway recently committed up to $1 billion to the Amazon fund. The United Nations' Reducing Emissions from Deforestation and forest Degradation (REDD) program also financially supports national activities of 13 countries worldwide. The primary assumption inherent in paying for avoiding deforestation is that avoided land use change emissions contribute towards climate change mitigation. In addition, the standing forests that are spared deforestation contribute towards additional carbon sinks associated with the CO2 fertilization effect. Implicit in this reasoning is the understanding that the carbon sinks provided by avoided deforestation have some "permanence" associated with them, at least in the order of 50-100 years. Clearly, if "avoided deforestation" is essentially "delayed deforestation" then the benefits will not be long lasting. More importantly, changes in climate have the potential to adversely affect the permanence of carbon sinks, whether they are being paid for or not. This presentation will address the question of "permanence" by analyzing simulations of the second generation Canadian Earth system model (CanESM2) that are contributing results to the upcoming fifth Coupled Modeled Intercomparison Project (CMIP5). CanESM2 results for the future RCP 2.6, 4.5 and 8.5 scenarios show, that due to reduced future precipitation, the Amazonian region remains a net source of carbon over the 21st century in all scenarios. The carbon losses during the recent 2005 and 2010 droughts in the Amazonian region nearly wiped away the gains made during a decade indicating that the era of intact Amazonian forests acting as carbon sinks may be over. CanESM2 simulations imply that the future of the Amazonian region may look more like these drought years, suggesting that the future reduced precipitation over the region can indeed "tip over" the Amazonian forests.
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Impact of pre-Columbian “geoglyph” builders on Amazonian forests
Watling, Jennifer; Iriarte, José; Schaan, Denise; Pessenda, Luiz C. R.; Loader, Neil J.; Dickau, Ruth E.; Damasceno, Antonia; Ranzi, Alceu
2017-01-01
Over 450 pre-Columbian (pre-AD 1492) geometric ditched enclosures (“geoglyphs”) occupy ∼13,000 km2 of Acre state, Brazil, representing a key discovery of Amazonian archaeology. These huge earthworks were concealed for centuries under terra firme (upland interfluvial) rainforest, directly challenging the “pristine” status of this ecosystem and its perceived vulnerability to human impacts. We reconstruct the environmental context of geoglyph construction and the nature, extent, and legacy of associated human impacts. We show that bamboo forest dominated the region for ≥6,000 y and that only small, temporary clearings were made to build the geoglyphs; however, construction occurred within anthropogenic forest that had been actively managed for millennia. In the absence of widespread deforestation, exploitation of forest products shaped a largely forested landscape that survived intact until the late 20th century. PMID:28167791
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Impact of pre-Columbian "geoglyph" builders on Amazonian forests.
Watling, Jennifer; Iriarte, José; Mayle, Francis E; Schaan, Denise; Pessenda, Luiz C R; Loader, Neil J; Street-Perrott, F Alayne; Dickau, Ruth E; Damasceno, Antonia; Ranzi, Alceu
2017-02-21
Over 450 pre-Columbian (pre-AD 1492) geometric ditched enclosures ("geoglyphs") occupy ∼13,000 km 2 of Acre state, Brazil, representing a key discovery of Amazonian archaeology. These huge earthworks were concealed for centuries under terra firme (upland interfluvial) rainforest, directly challenging the "pristine" status of this ecosystem and its perceived vulnerability to human impacts. We reconstruct the environmental context of geoglyph construction and the nature, extent, and legacy of associated human impacts. We show that bamboo forest dominated the region for ≥6,000 y and that only small, temporary clearings were made to build the geoglyphs; however, construction occurred within anthropogenic forest that had been actively managed for millennia. In the absence of widespread deforestation, exploitation of forest products shaped a largely forested landscape that survived intact until the late 20th century.
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NASA Astrophysics Data System (ADS)
Couto-Santos, F. R.; Luizao, F. J.
2014-12-01
The forests-savanna advancement/retraction process seems to play an important role in the global carbon cycle and in the climate-vegetation balance maintenance in the Amazon. To contribute with long term carbon dynamics and assess effectiveness of a protected area in reduce carbon emissions in Brazilian Amazon transitional areas, variations in forest-savanna mosaics biomass and carbon stock within Maraca Ecological Station (MES), Roraima/Brazil, and its outskirts non-protected areas were compared. Composite surface soil samples and indirect methods based on regression models were used to estimate aboveground tree biomass accumulation and assess vegetation and soil carbon stock along eleven 0.6 ha transects perpendicular to the forest-savanna limits. Aboveground biomass and carbon accumulation were influenced by vegetation structure, showing higher values within protected area, with great contribution of trees above 40 cm in diameter. In the savanna environments of protected areas, a higher tree density and carbon stock up to 30 m from the border confirmed a forest encroachment. This pointed that MES acts as carbon sink, even under variations in soil fertility gradient, with a potential increase of the total carbon stock from 9 to 150 Mg C ha-1. Under 20 years of fire and disturbance management, the results indicated the effectiveness of this protected area to reduce carbon emissions and mitigate greenhouse and climate change effects in a forest-savanna transitional area in Brazilian Northern Amazon. The contribution of this study in understanding rates and reasons for biomass and carbon variation, under different management strategies, should be considered the first approximation to assist policies of reducing emissions from deforestation and forest degradation (REDD) from underresearched Amazonian ecotone; despite further efforts in this direction are still needed. FINANCIAL SUPPORT: Boticário Group Foundation (Fundação Grupo Boticário); National Council for Scientific and Technological Development (CNPq); Minas Gerais State Research Foundation (FAPEMIG).
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Legacy Effect of Amazonian Drought Delays the Season Transition from Dry to Wet
NASA Astrophysics Data System (ADS)
Shi, M.; Liu, J.; Wong, S.; Worden, J. R.; Fisher, J.; Frankenberg, C.
2017-12-01
The long-term drought effect on forest coverage, so-called legacy effect, has been observed in ground and remote sensing measurements. Drought and forest loss may amplify each other through vegetation-atmosphere feedbacks. In this study, we investigate the impact of the reduced growth of southern Amazonian forest from the 2005 drought on dry-to-wet season transition and its variations in 2005 and 2006. We quantified the vegetation-atmosphere feedbacks with the Community Atmosphere Model version 5 (CAM5) with a control and a sensitivity experiments. We further investigate the mechanism of vegetation-atmosphere feedbacks with data-constrained evapotranspiration (ET) and HDO/H2O observations from the Scanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) and from the Tropospheric Emission Spectrometer (TES). Our results show that the dry season end (DSE) in southern Amazonian forest was delayed by 15 days in 2005 and by 25 days in 2006 with drought induced leaf carbon pool reduction. The postponed DSE is triggered by the reduced evapotranspiration (ET), but amplified by change of large-scale circulation. The reduction of ET and its delaying effect on dry-wet season transition is further confirmed with SCIAMACHY and TES HDO/H2O measurements.
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Cosme, Luiza H M; Schietti, Juliana; Costa, Flávia R C; Oliveira, Rafael S
2017-07-01
Species distributions and assemblage composition may be the result of trait selection through environmental filters. Here, we ask whether filtering of species at the local scale could be attributed to their hydraulic architectural traits, revealing the basis of hydrological microhabitat partitioning in a Central Amazonian forest. We analyzed the hydraulic characteristics at tissue (anatomical traits, wood specific gravity (WSG)), organ (leaf area, specific leaf area (SLA), leaf area : sapwood area ratio) and whole-plant (height) levels for 28 pairs of congeneric species from 14 genera restricted to either valleys or plateaus of a terra-firme forest in Central Amazonia. On plateaus, species had higher WSG, but lower mean vessel area, mean vessel hydraulic diameter, sapwood area and SLA than in valleys; traits commonly associated with hydraulic safety. Mean vessel hydraulic diameter and mean vessel area increased with height for both habitats, but leaf area and leaf area : sapwood area ratio investments with tree height declined in valley vs plateau species. [Correction added after online publication 29 March 2017: the preceding sentence has been reworded.] Two strategies for either efficiency or safety were detected, based on vessel size or allocation to sapwood. In conclusion, contrasting hydrological conditions act as environmental filters, generating differences in species composition at the local scale. This has important implications for the prediction of species distributions under future climate change scenarios. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.
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Mendes, Diego Matheus De Mello; Chamorro-Rengifo, Juliana; Rafael, José Albertino
2016-09-12
Most of the predatory katydids Listroscelidini species known were described from the Brazilian Atlantic Forest. Here a new genus and species from the Amazonian Rainforest is described. Based on its morphological characteristics, this new genus represents an intermediate form between two closely related genera, Listroscelis Serville and Monocerophora Walker.
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Airborne observations reveal elevational gradient in tropical forest isoprene emissions.
Gu, Dasa; Guenther, Alex B; Shilling, John E; Yu, Haofei; Huang, Maoyi; Zhao, Chun; Yang, Qing; Martin, Scot T; Artaxo, Paulo; Kim, Saewung; Seco, Roger; Stavrakou, Trissevgeni; Longo, Karla M; Tóta, Julio; de Souza, Rodrigo Augusto Ferreira; Vega, Oscar; Liu, Ying; Shrivastava, Manish; Alves, Eliane G; Santos, Fernando C; Leng, Guoyong; Hu, Zhiyuan
2017-05-23
Isoprene dominates global non-methane volatile organic compound emissions, and impacts tropospheric chemistry by influencing oxidants and aerosols. Isoprene emission rates vary over several orders of magnitude for different plants, and characterizing this immense biological chemodiversity is a challenge for estimating isoprene emission from tropical forests. Here we present the isoprene emission estimates from aircraft eddy covariance measurements over the Amazonian forest. We report isoprene emission rates that are three times higher than satellite top-down estimates and 35% higher than model predictions. The results reveal strong correlations between observed isoprene emission rates and terrain elevations, which are confirmed by similar correlations between satellite-derived isoprene emissions and terrain elevations. We propose that the elevational gradient in the Amazonian forest isoprene emission capacity is determined by plant species distributions and can substantially explain isoprene emission variability in tropical forests, and use a model to demonstrate the resulting impacts on regional air quality.
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Disease concepts and treatment by tribal healers of an Amazonian forest culture.
Herndon, Christopher N; Uiterloo, Melvin; Uremaru, Amasina; Plotkin, Mark J; Emanuels-Smith, Gwendolyn; Jitan, Jeetendra
2009-10-12
The extensive medicinal plant knowledge of Amazonian tribal peoples is widely recognized in the scientific literature and celebrated in popular lore. Despite this broad interest, the ethnomedical systems and knowledge of disease which guide indigenous utilization of botanical diversity for healing remain poorly characterized and understood. No study, to our knowledge, has attempted to directly examine patterns of actual disease recognition and treatment by healers of an Amazonian indigenous culture. The establishment of traditional medicine clinics, operated and directed by elder tribal shamans in two remote Trio villages of the Suriname rainforest, presented a unique investigational opportunity. Quantitative analysis of clinic records from both villages permitted examination of diseases treated over a continuous period of four years. Cross-cultural comparative translations were articulated of recorded disease conditions through ethnographic interviews of elder Trio shamans and a comprehensive atlas of indigenous anatomical nomenclature was developed. 20,337 patient visits within the period 2000 to 2004 were analyzed. 75 disease conditions and 127 anatomical terms are presented. Trio concepts of disease and medical practices are broadly examined within the present and historical state of their culture. The findings of this investigation support the presence of a comprehensive and highly formalized ethnomedical institution within Trio culture with attendant health policy and conservation implications.
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Disease concepts and treatment by tribal healers of an Amazonian forest culture
Herndon, Christopher N; Uiterloo, Melvin; Uremaru, Amasina; Plotkin, Mark J; Emanuels-Smith, Gwendolyn; Jitan, Jeetendra
2009-01-01
Background The extensive medicinal plant knowledge of Amazonian tribal peoples is widely recognized in the scientific literature and celebrated in popular lore. Despite this broad interest, the ethnomedical systems and knowledge of disease which guide indigenous utilization of botanical diversity for healing remain poorly characterized and understood. No study, to our knowledge, has attempted to directly examine patterns of actual disease recognition and treatment by healers of an Amazonian indigenous culture. Methods The establishment of traditional medicine clinics, operated and directed by elder tribal shamans in two remote Trio villages of the Suriname rainforest, presented a unique investigational opportunity. Quantitative analysis of clinic records from both villages permitted examination of diseases treated over a continuous period of four years. Cross-cultural comparative translations were articulated of recorded disease conditions through ethnographic interviews of elder Trio shamans and a comprehensive atlas of indigenous anatomical nomenclature was developed. Results 20,337 patient visits within the period 2000 to 2004 were analyzed. 75 disease conditions and 127 anatomical terms are presented. Trio concepts of disease and medical practices are broadly examined within the present and historical state of their culture. Conclusion The findings of this investigation support the presence of a comprehensive and highly formalized ethnomedical institution within Trio culture with attendant health policy and conservation implications. PMID:19821968
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Soil charcoal as long-term pyrogenic carbon storage in Amazonian seasonal forests.
Turcios, Maryory M; Jaramillo, Margarita M A; do Vale, José F; Fearnside, Philip M; Barbosa, Reinaldo Imbrozio
2016-01-01
Forest fires (paleo + modern) have caused charcoal particles to accumulate in the soil vertical profile in Amazonia. This forest compartment is a long-term carbon reservoir with an important role in global carbon balance. Estimates of stocks remain uncertain in forests that have not been altered by deforestation but that have been impacted by understory fires and selective logging. We estimated the stock of pyrogenic carbon derived from charcoal accumulated in the soil profile of seasonal forest fragments impacted by fire and selective logging in the northern portion of Brazilian Amazonia. Sixty-nine soil cores to 1-m depth were collected in 12 forest fragments of different sizes. Charcoal stocks averaged 3.45 ± 2.17 Mg ha(-1) (2.24 ± 1.41 Mg C ha(-1) ). Pyrogenic carbon was not directly related to the size of the forest fragments. This carbon is equivalent to 1.40% (0.25% to 4.04%) of the carbon stocked in aboveground live tree biomass in these fragments. The vertical distribution of pyrogenic carbon indicates an exponential model, where the 0-30 cm depth range has 60% of the total stored. The total area of Brazil's Amazonian seasonal forests and ecotones not altered by deforestation implies 65-286 Tg of pyrogenic carbon accumulated along the soil vertical profile. This is 1.2-2.3 times the total amount of residual pyrogenic carbon formed by biomass burning worldwide in 1 year. Our analysis suggests that the accumulated charcoal in the soil vertical profile in Amazonian forests is a substantial pyrogenic carbon pool that needs to be considered in global carbon models. © 2015 John Wiley & Sons Ltd.
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Impacts of Landscape Context on Patterns of Wind Downfall Damage in a Fragmented Amazonian Landscape
NASA Astrophysics Data System (ADS)
Schwartz, N.; Uriarte, M.; DeFries, R. S.; Gutierrez-Velez, V. H.; Fernandes, K.; Pinedo-Vasquez, M.
2015-12-01
Wind is a major disturbance in the Amazon and has both short-term impacts and lasting legacies in tropical forests. Observed patterns of damage across landscapes result from differences in wind exposure and stand characteristics, such as tree stature, species traits, successional age, and fragmentation. Wind disturbance has important consequences for biomass dynamics in Amazonian forests, and understanding the spatial distribution and size of impacts is necessary to quantify the effects on carbon dynamics. In November 2013, a mesoscale convective system was observed over the study area in Ucayali, Peru, a highly human modified and fragmented forest landscape. We mapped downfall damage associated with the storm in order to ask: how does the severity of damage vary within forest patches, and across forest patches of different sizes and successional ages? We applied spectral mixture analysis to Landsat images from 2013 and 2014 to calculate the change in non-photosynthetic vegetation fraction after the storm, and combined it with C-band SAR data from the Sentinel-1 satellite to predict downfall damage measured in 30 field plots using random forest regression. We then applied this model to map damage in forests across the study area. Using a land cover classification developed in a previous study, we mapped secondary and mature forest, and compared the severity of damage in the two. We found that damage was on average higher in secondary forests, but patterns varied spatially. This study demonstrates the utility of using multiple sources of satellite data for mapping wind disturbance, and adds to our understanding of the sources of variation in wind-related damage. Ultimately, an improved ability to map wind impacts and a better understanding of their spatial patterns can contribute to better quantification of carbon dynamics in Amazonian landscapes.
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Rapid tree carbon stock recovery in managed Amazonian forests.
Rutishauser, Ervan; Hérault, Bruno; Baraloto, Christopher; Blanc, Lilian; Descroix, Laurent; Sotta, Eleneide Doff; Ferreira, Joice; Kanashiro, Milton; Mazzei, Lucas; d'Oliveira, Marcus V N; de Oliveira, Luis C; Peña-Claros, Marielos; Putz, Francis E; Ruschel, Ademir R; Rodney, Ken; Roopsind, Anand; Shenkin, Alexander; da Silva, Katia E; de Souza, Cintia R; Toledo, Marisol; Vidal, Edson; West, Thales A P; Wortel, Verginia; Sist, Plinio
2015-09-21
While around 20% of the Amazonian forest has been cleared for pastures and agriculture, one fourth of the remaining forest is dedicated to wood production. Most of these production forests have been or will be selectively harvested for commercial timber, but recent studies show that even soon after logging, harvested stands retain much of their tree-biomass carbon and biodiversity. Comparing species richness of various animal taxa among logged and unlogged forests across the tropics, Burivalova et al. found that despite some variability among taxa, biodiversity loss was generally explained by logging intensity (the number of trees extracted). Here, we use a network of 79 permanent sample plots (376 ha total) located at 10 sites across the Amazon Basin to assess the main drivers of time-to-recovery of post-logging tree carbon (Table S1). Recovery time is of direct relevance to policies governing management practices (i.e., allowable volumes cut and cutting cycle lengths), and indirectly to forest-based climate change mitigation interventions. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Fast demographic traits promote high diversification rates of Amazonian trees
Baker, Timothy R; Pennington, R Toby; Magallon, Susana; Gloor, Emanuel; Laurance, William F; Alexiades, Miguel; Alvarez, Esteban; Araujo, Alejandro; Arets, Eric J M M; Aymard, Gerardo; de Oliveira, Atila Alves; Amaral, Iêda; Arroyo, Luzmila; Bonal, Damien; Brienen, Roel J W; Chave, Jerome; Dexter, Kyle G; Di Fiore, Anthony; Eler, Eduardo; Feldpausch, Ted R; Ferreira, Leandro; Lopez-Gonzalez, Gabriela; van der Heijden, Geertje; Higuchi, Niro; Honorio, Eurídice; Huamantupa, Isau; Killeen, Tim J; Laurance, Susan; Leaño, Claudio; Lewis, Simon L; Malhi, Yadvinder; Marimon, Beatriz Schwantes; Marimon Junior, Ben Hur; Monteagudo Mendoza, Abel; Neill, David; Peñuela-Mora, Maria Cristina; Pitman, Nigel; Prieto, Adriana; Quesada, Carlos A; Ramírez, Fredy; Ramírez Angulo, Hirma; Rudas, Agustin; Ruschel, Ademir R; Salomão, Rafael P; de Andrade, Ana Segalin; Silva, J Natalino M; Silveira, Marcos; Simon, Marcelo F; Spironello, Wilson; ter Steege, Hans; Terborgh, John; Toledo, Marisol; Torres-Lezama, Armando; Vasquez, Rodolfo; Vieira, Ima Célia Guimarães; Vilanova, Emilio; Vos, Vincent A; Phillips, Oliver L; Wiens, John
2014-01-01
The Amazon rain forest sustains the world's highest tree diversity, but it remains unclear why some clades of trees are hyperdiverse, whereas others are not. Using dated phylogenies, estimates of current species richness and trait and demographic data from a large network of forest plots, we show that fast demographic traits – short turnover times – are associated with high diversification rates across 51 clades of canopy trees. This relationship is robust to assuming that diversification rates are either constant or decline over time, and occurs in a wide range of Neotropical tree lineages. This finding reveals the crucial role of intrinsic, ecological variation among clades for understanding the origin of the remarkable diversity of Amazonian trees and forests. PMID:24589190
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NASA Technical Reports Server (NTRS)
Matson, Pamela A.; Vitousek, Peter M.
1987-01-01
Soil nitrogen transformations and nitrous oxide flux across the soil-air interface have been measured in a variety of tropical forest sites and correlated with patterns of nitrogen circulation. Nitrogen mineralizaton and nitrification potentials were found to be high in the relatively fertile Costa Rica sites and the Amazonian oxisol/ultisols, intermediate in Amazonian white sand soils, and low in the Hawaiian montane sites. Nitrous oxide fluxes ranged from 0 to 6.2 ng/sq cm per h, and the mean flux per site was shown to be highly correlated with mean nitrogen mineralization.
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Zhang, Ke; de Almeida Castanho, Andrea D; Galbraith, David R; Moghim, Sanaz; Levine, Naomi M; Bras, Rafael L; Coe, Michael T; Costa, Marcos H; Malhi, Yadvinder; Longo, Marcos; Knox, Ryan G; McKnight, Shawna; Wang, Jingfeng; Moorcroft, Paul R
2015-02-20
There is considerable interest in understanding the fate of the Amazon over the coming century in the face of climate change, rising atmospheric CO 2 levels, ongoing land transformation, and changing fire regimes within the region. In this analysis, we explore the fate of Amazonian ecosystems under the combined impact of these four environmental forcings using three terrestrial biosphere models (ED2, IBIS, and JULES) forced by three bias-corrected IPCC AR4 climate projections (PCM1, CCSM3, and HadCM3) under two land-use change scenarios. We assess the relative roles of climate change, CO 2 fertilization, land-use change, and fire in driving the projected changes in Amazonian biomass and forest extent. Our results indicate that the impacts of climate change are primarily determined by the direction and severity of projected changes in regional precipitation: under the driest climate projection, climate change alone is predicted to reduce Amazonian forest cover by an average of 14%. However, the models predict that CO 2 fertilization will enhance vegetation productivity and alleviate climate-induced increases in plant water stress, and, as a result, sustain high biomass forests, even under the driest climate scenario. Land-use change and climate-driven changes in fire frequency are predicted to cause additional aboveground biomass loss and reductions in forest extent. The relative impact of land use and fire dynamics compared to climate and CO 2 impacts varies considerably, depending on both the climate and land-use scenario, and on the terrestrial biosphere model used, highlighting the importance of improved quantitative understanding of all four factors - climate change, CO 2 fertilization effects, fire, and land use - to the fate of the Amazon over the coming century. © 2015 John Wiley & Sons Ltd.
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Mosquito (Diptera: Culicidae) diversity of a forest-fragment mosaic in the Amazon rain forest.
Hutchings, Rosa Sá Gomes; Sallum, Maria Anice Mureb; Hutchings, Roger William
2011-03-01
To study the impact of Amazonian forest fragmentation on the mosquito fauna, an inventory of Culicidae was conducted in the upland forest research areas of the Biological Dynamics of Forest Fragments Project located 60 km north of Manaus, Amazonas, Brazil. The culicid community was sampled monthly between February 2002 and May 2003. CDC light traps, flight interception traps, manual aspiration, and net sweeping were used to capture adult specimens along the edges and within forest fragments of different sizes (1, 10, and 100 ha), in second-growth areas surrounding the fragments and around camps. We collected 5,204 specimens, distributed in 18 genera and 160 species level taxa. A list of mosquito taxa is presented with 145 species found in the survey, including seven new records for Brazil, 16 new records for the state of Amazonas, along with the 15 morphotypes that probably represent undescribed species. No exotic species [Aedes aegypti (L.) and Aedes albopictus (Skuse)] were found within the sampled areas. Several species collected are potential vectors of Plasmodium causing human malaria and of various arboviruses. The epidemiological and ecological implications of mosquito species found are discussed, and the results are compared with other mosquito inventories from the Amazon region.
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Carbon recovery dynamics following disturbance by selective logging in Amazonian forests
Piponiot, Camille; Sist, Plinio; Mazzei, Lucas; Peña-Claros, Marielos; Putz, Francis E; Rutishauser, Ervan; Shenkin, Alexander; Ascarrunz, Nataly; de Azevedo, Celso P; Baraloto, Christopher; França, Mabiane; Guedes, Marcelino; Honorio Coronado, Eurídice N; d'Oliveira, Marcus VN; Ruschel, Ademir R; da Silva, Kátia E; Doff Sotta, Eleneide; de Souza, Cintia R; Vidal, Edson; West, Thales AP; Hérault, Bruno
2016-01-01
When 2 Mha of Amazonian forests are disturbed by selective logging each year, more than 90 Tg of carbon (C) is emitted to the atmosphere. Emissions are then counterbalanced by forest regrowth. With an original modelling approach, calibrated on a network of 133 permanent forest plots (175 ha total) across Amazonia, we link regional differences in climate, soil and initial biomass with survivors’ and recruits’ C fluxes to provide Amazon-wide predictions of post-logging C recovery. We show that net aboveground C recovery over 10 years is higher in the Guiana Shield and in the west (21 ±3 Mg C ha-1) than in the south (12 ±3 Mg C ha-1) where environmental stress is high (low rainfall, high seasonality). We highlight the key role of survivors in the forest regrowth and elaborate a comprehensive map of post-disturbance C recovery potential in Amazonia. DOI: http://dx.doi.org/10.7554/eLife.21394.001 PMID:27993185
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Prates, Ivan; Rivera, Danielle; Rodrigues, Miguel T; Carnaval, Ana C
2016-10-01
Shifts in the geographic distribution of habitats over time can promote dispersal and vicariance, thereby influencing large-scale biogeographic patterns and ecological processes. An example is that of transient corridors of suitable habitat across disjunct but ecologically similar regions, which have been associated with climate change over time. Such connections likely played a role in the assembly of tropical communities, especially within the highly diverse Amazonian and Atlantic rainforests of South America. Although these forests are presently separated by open and dry ecosystems, paleoclimatic and phylogenetic evidence suggest that they have been transiently connected in the past. However, little is known about the timing, magnitude and the distribution of former forest connections. We employ sequence data at multiple loci from three codistributed arboreal lizards (Anolis punctatus, Anolis ortonii and Polychrus marmoratus) to infer the phylogenetic relationships among Amazonian and Atlantic Forest populations and to test alternative historical demographic scenarios of colonization and vicariance using coalescent simulations and approximate Bayesian computation (ABC). Data from the better-sampled Anolis species support colonization of the Atlantic Forest from eastern Amazonia. Hierarchical ABC indicates that the three species colonized the Atlantic Forest synchronously during the mid-Pleistocene. We find support of population bottlenecks associated with founder events in the two Anolis, but not in P. marmoratus, consistently with their distinct ecological tolerances. Our findings support that climatic fluctuations provided key opportunities for dispersal and forest colonization in eastern South America through the cessation of environmental barriers. Evidence of species-specific histories strengthens assertions that biological attributes play a role in responses to shared environmental change. © 2016 John Wiley & Sons Ltd.
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Cadete, Raquel M; Melo, Monaliza A; Lopes, Mariana R; Pereira, Gilmara M D; Zilli, Jerri E; Vital, Marcos J S; Gomes, Fátima C O; Lachance, Marc-André; Rosa, Carlos A
2012-06-01
Five strains of a novel yeast species were isolated from rotting wood samples collected in an Amazonian forest site in the state of Roraima, northern Brazil. The sequences of the D1/D2 domains of the large subunit of the rRNA gene showed that this species belongs to the Scheffersomyces clade and is related to Candida coipomoensis, Candida lignicola and Candida queiroziae. The novel species Candida amazonensis sp. nov. is proposed to accommodate these isolates. The type strain of C. amazonensis sp. nov. is UFMG-HMD-26.3(T) ( = CBS 12363(T) = NRRL Y-48762(T)).
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Harvesting intensity affects forest structure and composition in an upland Amazonian forest
John A. Parrotta; John K. Francis; Oliver H. Knowles; NO-VALUE
2002-01-01
Forest structure and floristic composition were studied in a series of 0.5 ha natural forest plots at four sites near Porto Trombetas in Pará State, Brazil, 11–12 years after being subjected to differing levels of above-ground biomass harvest and removal. In addition to undisturbed control plots, experimental treatments included: removal of...
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Persistent effects of a severe drought on Amazonian forest canopy.
Saatchi, Sassan; Asefi-Najafabady, Salvi; Malhi, Yadvinder; Aragão, Luiz E O C; Anderson, Liana O; Myneni, Ranga B; Nemani, Ramakrishna
2013-01-08
Recent Amazonian droughts have drawn attention to the vulnerability of tropical forests to climate perturbations. Satellite and in situ observations have shown an increase in fire occurrence during drought years and tree mortality following severe droughts, but to date there has been no assessment of long-term impacts of these droughts across landscapes in Amazonia. Here, we use satellite microwave observations of rainfall and canopy backscatter to show that more than 70 million hectares of forest in western Amazonia experienced a strong water deficit during the dry season of 2005 and a closely corresponding decline in canopy structure and moisture. Remarkably, and despite the gradual recovery in total rainfall in subsequent years, the decrease in canopy backscatter persisted until the next major drought, in 2010. The decline in backscatter is attributed to changes in structure and water content associated with the forest upper canopy. The persistence of low backscatter supports the slow recovery (>4 y) of forest canopy structure after the severe drought in 2005. The result suggests that the occurrence of droughts in Amazonia at 5-10 y frequency may lead to persistent alteration of the forest canopy.
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Scaling properties reveal regulation of river flows in the Amazon through a
forest reservoir
NASA Astrophysics Data System (ADS)
Salazar, Juan Fernando; Villegas, Juan Camilo; María Rendón, Angela; Rodríguez, Estiven; Hoyos, Isabel; Mercado-Bettín, Daniel; Poveda, Germán
2018-03-01
Many natural and social phenomena depend on river flow regimes that are being altered by global change. Understanding the mechanisms behind such alterations is crucial for predicting river flow regimes in a changing environment. Here we introduce a novel physical interpretation of the scaling properties of river flows and show that it leads to a parsimonious characterization of the flow regime of any river basin. This allows river basins to be classified as regulated or unregulated, and to identify a critical threshold between these states. We applied this framework to the Amazon river basin and found both states among its main tributaries. Then we introduce the
forest reservoir
hypothesis to describe the natural capacity of river basins to regulate river flows through land-atmosphere interactions (mainly precipitation recycling) that depend strongly on the presence of forests. A critical implication is that forest loss can force the Amazonian river basins from regulated to unregulated states. Our results provide theoretical and applied foundations for predicting hydrological impacts of global change, including the detection of early-warning signals for critical transitions in river basins. -
Fortini, Lucas Berio; Bruna, Emilio M; Zarin, Daniel J; Vasconcelos, Steel S; Miranda, Izildinha S
2010-04-01
Despite research demonstrating that water and nutrient availability exert strong effects on multiple ecosystem processes in tropical forests, little is known about the effect of these factors on the demography and population dynamics of tropical trees. Over the course of 5 years, we monitored two common Amazonian secondary forest species-Lacistema pubescens and Myrcia sylvatica-in dry-season irrigation, litter-removal and control plots. We then evaluated the effects of altered water and nutrient availability on population demography and dynamics using matrix models and life table response experiments. Our results show that despite prolonged experimental manipulation of water and nutrient availability, there were nearly no consistent and unidirectional treatment effects on the demography of either species. The patterns and significance of observed treatment effects were largely dependent on cross-year variability not related to rainfall patterns, and disappeared once we pooled data across years. Furthermore, most of these transient treatment effects had little effect on population growth rates. Our results suggest that despite major experimental manipulations of water and nutrient availability-factors considered critical to the ecology of tropical pioneer tree species-autogenic light limitation appears to be the primary regulator of tree demography at early/mid successional stages. Indeed, the effects of light availability may completely override those of other factors thought to influence the successional development of Amazonian secondary forests.
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Three new species of Aspergillus from Amazonian forest soil (Ecuador).
Mares, Donatella; Andreotti, Elisa; Maldonado, Maria Elena; Pedrini, Paola; Colalongo, Chiara; Romagnoli, Carlo
2008-09-01
From an undisturbed natural forest soil in Ecuador, three fungal strains of the genus Aspergillus were isolated. Based on molecular and morphological features they are described as three new species, named A. quitensis, A. amazonicus, and A. ecuadorensis.
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Elemental mercury in the atmosphere of a tropical Amazonian forest (French Guiana)
DOE Office of Scientific and Technical Information (OSTI.GOV)
Amouroux, D.; Wasserman, J.C.Tessier, E.; Donard, O.F.X.
1999-09-01
Gaseous atmospheric mercury was investigated at two sites of a tropical Amazonian forest (French Guiana) in the Petit Inini River basin and the Petit Saut Lake in June, 1998. Gaseous atmospheric mercury was identified as elemental mercury (Hg{sup 0}). Diurnal variation of atmospheric Hg{sup 0} in both studied aquatic environments were significantly correlated with air temperature and anticorrelated with relative humidity. Average Hg{sup 0} concentrations were higher above the Petit Inini River that the Petit Saut Lake. Background Hg{sup 0} concentrations in the Petit Inini River basin were higher than those observed in remote environments. These data suggest that goldmore » mining activity (i.e., Petit Inini River basin) may influence mercury mobilization in tropical forest ecosystems and that atmospheric transfer is a major pathway for mercury cycling in these environments.« less
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Avian distribution in treefall gaps and understorey of terra firme forest in the lowland Amazon
JR WUNDERLE; MICHAEL R. WILLIG; LUIZA MAGALLI PINTO HENRIQUES
2005-01-01
We compared the bird distributions in the understorey of treefall gaps and sites with intact canopy in Amazonian terra firme forest in Brazil. We compiled 2216 mist-net captures (116 species) in 32 gap and 32 forest sites over 22.3 months. Gap habitats differed from forest habitats in having higher capture rates, total captures, species richness and diversity....
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Luke L. Powell; Gustavo Zurita; Jared D. Wolfe; Erik I. Johnson; Philip C Stouffer
2015-01-01
Primary tropical rain forests are being rapidly perforated with new edges via roads, logging, and pastures, and vast areas of secondary forest accumulate following abandonment of agricultural lands. To determine how insectivorous Amazonian understory birds respond to edges between primary rain forest and three age classes of secondary forest, we radio-tracked two...
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Marco W Lentini; Johan C Zweede; Thomas P Holmes
2010-01-01
Sound forest management practices have been seen as an interesting strategy to ally forest conservation and rural economic development in Amazônia. However, the implementation of Reduced Impact Logging (RIL) techniques in the field has been incipient, while most of the Amazonian timber production is generated through predatory and illegal logging. Despite several...
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Oliver H. Knowles; John A. Parrotta
1995-01-01
One hundred and sixty taxa of upland moist forest trees were studied with reference to their suitability for forest restoration on bauxite mined Iands in western Para State, Brazil. Over a 14-year period, field observations in native primary forests, nursery studies, and evaluations of over 600 ha of mixed-species reforestation areas were used to characterize fruiting...
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Martínez-Ortega, Cristina; Santos, Eduardo SA; Gil, Diego
2014-01-01
Eye size shows a large degree of variation among species, even after correcting for body size. In birds, relatively larger eyes have been linked to predation risk, capture of mobile prey, and nocturnal habits. Relatively larger eyes enhance visual acuity and also allow birds to forage and communicate in low-light situations. Complex habitats such as tropical rain forests provide a mosaic of diverse lighting conditions, including differences among forest strata and at different distances from the forest edge. We examined in an Amazonian forest bird community whether microhabitat occupancy (defined by edge avoidance and forest stratum) was a predictor of relative eye size. We found that relative eye size increased with edge avoidance, but did not differ according to forest stratum. Nevertheless, the relationship between edge avoidance and relative eye size showed a nonsignificant positive trend for species that inhabit lower forest strata. Our analysis shows that birds that avoid forest edges have larger eyes than those living in lighter parts. We expect that this adaptation may allow birds to increase their active daily period in dim areas of the forest. The pattern that we found raises the question of what factors may limit the evolution of large eyes. PMID:25614788
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Oil palm monoculture induces drastic erosion of an Amazonian forest mammal fauna
Maués, Paula Cristina R. de A.; Oliveira, Geovana Linhares; Mineiro, Ivo G. B.; de Maria, Susanne L. Silva; Lima, Renata C. S.
2017-01-01
Oil palm monoculture comprises one of the most financially attractive land-use options in tropical forests, but cropland suitability overlaps the distribution of many highly threatened vertebrate species. We investigated how forest mammals respond to a landscape mosaic, including mature oil palm plantations and primary forest patches in Eastern Amazonia. Using both line-transect censuses (LTC) and camera-trapping (CT), we quantified the general patterns of mammal community structure and attempted to identify both species life-history traits and the environmental and spatial covariates that govern species intolerance to oil palm monoculture. Considering mammal species richness, abundance, and species composition, oil palm plantations were consistently depauperate compared to the adjacent primary forest, but responses differed between functional groups. The degree of forest habitat dependency was a leading trait, determining compositional dissimilarities across habitats. Considering both the LTC and CT data, distance from the forest-plantation interface had a significant effect on mammal assemblages within each habitat type. Approximately 87% of all species detected within oil palm were never farther than 1300 m from the forest edge. Our study clearly reinforces the notion that conventional oil palm plantations are extremely hostile to native tropical forest biodiversity, which does not bode well given prospects for oil palm expansion in both aging and new Amazonian deforestation frontiers. PMID:29117202
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Pulido-Santacruz, Paola; Aleixo, Alexandre; Weir, Jason T
2018-03-14
We possess limited understanding of how speciation unfolds in the most species-rich region of the planet-the Amazon basin. Hybrid zones provide valuable information on the evolution of reproductive isolation, but few studies of Amazonian vertebrate hybrid zones have rigorously examined the genome-wide underpinnings of reproductive isolation. We used genome-wide genetic datasets to show that two deeply diverged, but morphologically cryptic sister species of forest understorey birds show little evidence for prezygotic reproductive isolation, but substantial postzygotic isolation. Patterns of heterozygosity and hybrid index revealed that hybrid classes with heavily recombined genomes are rare and closely match simulations with high levels of selection against hybrids. Genomic and geographical clines exhibit a remarkable similarity across loci in cline centres, and have exceptionally narrow cline widths, suggesting that postzygotic isolation is driven by genetic incompatibilities at many loci, rather than a few loci of strong effect. We propose Amazonian understorey forest birds speciate slowly via gradual accumulation of postzygotic genetic incompatibilities, with prezygotic barriers playing a less important role. Our results suggest old, cryptic Amazonian taxa classified as subspecies could have substantial postzygotic isolation deserving species recognition and that species richness is likely to be substantially underestimated in Amazonia. © 2018 The Author(s).
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Echalar, F.; Gaudichet, A.; Cachier, H.
1995-11-15
This report characterizes and compares trace element emissions from fires of three different types of savannas and from the southwestern amazonian rain forest. This study tries to verify a fingerprint that may characterize savanna fires or tropical biomass burning.
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Simulating drought impacts on energy balance in an Amazonian rainforest
NASA Astrophysics Data System (ADS)
Imbuzeiro, H. A.; Costa, M. H.; Galbraith, D.; Christoffersen, B. O.; Powell, T.; Harper, A. B.; Levine, N. M.; Rowland, L.; Moorcroft, P. R.; Benezoli, V. H.; Meir, P.; da Costa, A. C. L.; Brando, P. M.; Malhi, Y.; Saleska, S. R.; Williams, M. D.
2014-12-01
The studies of the interaction between vegetation and climate change in the Amazon Basin indicate that up to half of the region's forests may be displaced by savanna vegetation by the end of the century. Additional analyses suggest that complex interactions among land use, fire-frequency, and episodic drought are driving an even more rapid process of the forest impoverishment and displacement referred here as "savannization". But it is not clear whether surface/ecosystem models are suitable to analyze extreme events like a drought. Long-term simulations of throughfall exclusion experiments has provided unique insights into the energy dynamics of Amazonian rainforests during drought conditions. In this study, we evaluate how well six surface/ecosystem models quantify the energy dynamics from two Amazonian throughfall exclusion experiments. All models were run for the Tapajós and Caxiuanã sites with one control plot using normal precipitation (i.e. do not impose a drought) and then the drought manipulation was imposed for several drought treatments (10 to 90% rainfall exclusion). The sap flow, net radiation (Rn), sensible (H), latent (LE) and ground (G) heat flux are used to analyze if the models are able to capture the dynamics of water stress and what the implications for the energy dynamics are. With respect to the model validation, when we compare the sap flow observed and transpiration simulated, models are more accurate to simulate control plots than drought treatments (50% rainfall exclusion). The results show that the models overestimate the sap flow data during the drought conditions, but they were able to capture the changes in the main energy balance components for different drought treatments. The Rn and LE decreased and H increased with more intensity of drought. The models sensitivity analysis indicate that models are more sensitive to drought when rainfall is excluded for more than 60% and when this reduction occurs during the dry season.
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NASA Astrophysics Data System (ADS)
Moorcroft, P. R.; Zhang, K.; Castanho, A. D. D. A.; Galbraith, D.; Moghim, S.; Levine, N. M.; Bras, R. L.; Coe, M. T.; Costa, M. H.; Malhi, Y.; Longo, M.; Knox, R. G.; McKnight, S. L.; Wang, J.
2014-12-01
There is considerable interest and uncertainty regarding the expected fate of the Amazon over the coming century in face of the combined impacts of climate change, rising atmospheric CO2 levels, and on-going land transformation in the region. In this analysis, we explore the fate of Amazonian ecosystems under projected climate, CO2 and land-use change in the 21st century using three state-of-the-art terrestrial biosphere models (ED2, IBIS, and JULES) driven by three representative, bias-corrected GCM climate projections (PCM1, CCSM3, and HadCM3) under the SRES A2 scenario, coupled with two land-use change scenarios. We assess the relative roles of climate change, CO2 fertilization, land-use change, and fire in driving the projected changes in Amazonian biomass and forest extent. Our results indicate that the impacts of climate change depend strongly on the direction and severity of projected changes in precipitation regimes within the region: under the driest climate projection, climate change alone is predicted to reduce Amazonian forest cover by an average of 14%; however, the models predict that CO2 fertilization will enhance vegetation productivity and alleviate climate-induced increases in plant water stress, and as a result sustain high biomass forests, even under the driest climate scenario. Land-use change and changes in fire frequency are predicted cause additional aboveground live biomass loss and changes in forest extent. The relative impact of land-use and fire dynamics versus the impacts of climate and CO2 on the Amazon varies considerably, depending on both the climate and land-use scenarios used and on the terrestrial biosphere model, highlighting the importance of improved understanding of all four factors -- future climate, CO2 fertilization effects, fire and land-use -- to the fate of the Amazon over the coming century.
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Cadete, Raquel M; Melo, Monaliza A; Dussán, Kelly J; Rodrigues, Rita C L B; Silva, Silvio S; Zilli, Jerri E; Vital, Marcos J S; Gomes, Fátima C O; Lachance, Marc-André; Rosa, Carlos A
2012-01-01
This study is the first to investigate the Brazilian Amazonian Forest to identify new D-xylose-fermenting yeasts that might potentially be used in the production of ethanol from sugarcane bagasse hemicellulosic hydrolysates. A total of 224 yeast strains were isolated from rotting wood samples collected in two Amazonian forest reserve sites. These samples were cultured in yeast nitrogen base (YNB)-D-xylose or YNB-xylan media. Candida tropicalis, Asterotremella humicola, Candida boidinii and Debaryomyces hansenii were the most frequently isolated yeasts. Among D-xylose-fermenting yeasts, six strains of Spathaspora passalidarum, two of Scheffersomyces stipitis, and representatives of five new species were identified. The new species included Candida amazonensis of the Scheffersomyces clade and Spathaspora sp. 1, Spathaspora sp. 2, Spathaspora sp. 3, and Candida sp. 1 of the Spathaspora clade. In fermentation assays using D-xylose (50 g/L) culture medium, S. passalidarum strains showed the highest ethanol yields (0.31 g/g to 0.37 g/g) and productivities (0.62 g/L · h to 0.75 g/L · h). Candida amazonensis exhibited a virtually complete D-xylose consumption and the highest xylitol yields (0.55 g/g to 0.59 g/g), with concentrations up to 25.2 g/L. The new Spathaspora species produced ethanol and/or xylitol in different concentrations as the main fermentation products. In sugarcane bagasse hemicellulosic fermentation assays, S. stipitis UFMG-XMD-15.2 generated the highest ethanol yield (0.34 g/g) and productivity (0.2 g/L · h), while the new species Spathaspora sp. 1 UFMG-XMD-16.2 and Spathaspora sp. 2 UFMG-XMD-23.2 were very good xylitol producers. This study demonstrates the promise of using new D-xylose-fermenting yeast strains from the Brazilian Amazonian Forest for ethanol or xylitol production from sugarcane bagasse hemicellulosic hydrolysates.
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Circadian rhythms constrain leaf and canopy gas exchange in an Amazonian forest
NASA Astrophysics Data System (ADS)
Doughty, Christopher E.; Goulden, Michael L.; Miller, Scott D.; da Rocha, Humberto R.
2006-08-01
We used a controlled-environment leaf gas-exchange system and the micrometeorological technique eddy covariance to determine whether circadian rhythms constrain the rates of leaf and canopy gas exchange in an Amazonian forest over a day. When exposed to continuous and constant light for 20 to 48 hours leaves of eleven of seventeen species reduced their photosynthetic rates and closed their stomata during the normally dark period and resumed active gas exchange during the normally light period. Similarly, the rate of whole-forest CO2 uptake at a predetermined irradiance declined during the late afternoon and early morning and increased during the middle of the day. We attribute these cycles to circadian rhythms that are analogous to ones that have been reported for herbaceous plants in the laboratory. The importance of endogenous gas exchange rhythms presents a previously unrecognized challenge for efforts to both interpret and model land-atmosphere energy and mass exchange.
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Biogeochemistry and ecology of terrestrial ecosystems of Amazonia
NASA Astrophysics Data System (ADS)
Malhi, Yadvinder; Davidson, Eric A.
The last decade of research associated with the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA) has led to substantial advances in our understanding of the biogeochemistry and ecology of Amazonian forests and savannas, in particular in relation to the carbon cycle of Amazonia. In this chapter, we present a synthesis of results and ideas that are presented in more detail in subsequent chapters, drawing together evidence from studies of forest ecology, ecophysiology, trace gas fluxes and atmospheric flux towers, large-scale rainfall manipulation experiments and soil surveys, satellite remote sensing, and quantification of carbon and nutrient stocks and flows. The studies have demonstrated the variability of the functioning and biogeochemistry of Amazonian forests at a range of spatial and temporal scales, and they provide clues as to how Amazonia will respond to ongoing direct pressure and global atmospheric change. We conclude by highlighting key questions for the next decade of research to address.
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Methane flux from the Central Amazonian Floodplain
NASA Technical Reports Server (NTRS)
Bartlett, Karen B.; Crill, Patrick M.; Sebacher, Daniel I.; Harriss, Robert C.; Wilson, John O.; Melack, John M.
1987-01-01
A total of 186 methane measurements from the three primary Amazon floodplain environments of open water lakes, flood forests, and floating grass mats were made over the period 18 July through 2 September 1985. These data indicate that emissions were lowest over open water lakes. Flux from flooded forests and grass mats was significantly higher. At least three transport processes contribute to tropospheric emissions: ebullition from sediments, diffusion along the concentration gradient from sediment to overlaying water to air, and transport through the roots and stems of aquatic plants. Measurements indicate that the first two of these processes are most significant. It was estimated that on the average bubbling makes up 49% of the flux from open water, 54% of that from flooded forests, and 64% of that from floating mats. If the measurements were applied to the entire Amazonian floodplain, it is calculated that the region could supply up to 12% of the estimated global natural sources of methane.
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E. H. Helmer; M. A. Lefsky; D. A. Roberts
2009-01-01
We estimate the age of humid lowland tropical forests in Rondônia, Brazil, from a somewhat densely spaced time series of Landsat images (1975â2003) with an automated procedure, the Threshold Age Mapping Algorithm (TAMA), first described here. We then estimate a landscape-level rate of aboveground woody biomass accumulation of secondary forest by combining forest age...
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Post-Fire Changes in Forest Biomass Retrieved by Airborne LiDAR in Amazonia
Luciane Sato; Vitor Gomes; Yosio Shimabukuro; Michael Keller; Egidio Arai; Maiza dos-Santos; Irving Brown; Luiz Aragão
2016-01-01
Fire is one of the main factors directly impacting Amazonian forest biomass and dynamics. Because of Amazoniaâs large geographical extent, remote sensing techniques are required for comprehensively assessing forest fire impacts at the landscape level. In this context, Light Detection and Ranging (LiDAR) stands out as a technology capable of retrieving direct...
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Liberation: Acceptable production of tropical forest timber.
Frank H. Wadsworth; Johan Zweede
2006-01-01
Reduced impact logging in an eastern Amazonian terra firme forest left more than half of the next crop trees growing at a rate corresponding to a rotation of more than a century to attain 60-cm dbh. Two years after the logging, in 20 ha of the logged forest, tree competitors around crop trees were eliminated. Competitors were defined as trees whose crowns overtopped...
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Persistent effects of a severe drought on Amazonian forest canopy
Saatchi, Sassan; Asefi-Najafabady, Salvi; Malhi, Yadvinder; Aragão, Luiz E. O. C.; Anderson, Liana O.; Myneni, Ranga B.; Nemani, Ramakrishna
2013-01-01
Recent Amazonian droughts have drawn attention to the vulnerability of tropical forests to climate perturbations. Satellite and in situ observations have shown an increase in fire occurrence during drought years and tree mortality following severe droughts, but to date there has been no assessment of long-term impacts of these droughts across landscapes in Amazonia. Here, we use satellite microwave observations of rainfall and canopy backscatter to show that more than 70 million hectares of forest in western Amazonia experienced a strong water deficit during the dry season of 2005 and a closely corresponding decline in canopy structure and moisture. Remarkably, and despite the gradual recovery in total rainfall in subsequent years, the decrease in canopy backscatter persisted until the next major drought, in 2010. The decline in backscatter is attributed to changes in structure and water content associated with the forest upper canopy. The persistence of low backscatter supports the slow recovery (>4 y) of forest canopy structure after the severe drought in 2005. The result suggests that the occurrence of droughts in Amazonia at 5–10 y frequency may lead to persistent alteration of the forest canopy. PMID:23267086
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Spatially-Explicit Holocene Drought Reconstructions in Amazonian Forests
NASA Astrophysics Data System (ADS)
McMichael, C.; Bush, M. B.
2014-12-01
Climate models predict increasing drought in Amazonian forests over the next century, and the synergy of drought and fire may lead to forest dieback. El Niño Southern Oscillation (ENSO) and the Atlantic Multi-decadal Oscillation (AMO) are two primary drivers of Amazonian drought, and each process has a spatially distinct manifestation in the Basin. Paleoecological reconstructions can contextualize the forest response to past drought periods. Stalagmite and lake sediment records have documented that the early- to mid-Holocene, i.e. 10,000 - 5000 calibrated years before present (cal yr BP), was among the driest periods of the last 100,000 years in western Amazonia. Climatic conditions became wetter and more similar to the modern climate over the last 4000 cal yr BP, and fires rarely occurred in the absence of human activity. Yet there are currently no drought and fire reconstructions that examine the spatially explicit patterns of drought during the Holocene. Here, we present regional drought histories from southwestern and northeastern sections Amazonia for the last 10,000 years that document the drought-fire dynamics resulting from both climatic processes. Our reconstructions were based on a compilation of dated soil charcoal fragments (N= 291) collected from within Amazonia sensu stricto, which were analyzed by region using summed probability analysis. The compiled soil charcoal dates contained limited evidence of fire over the last 10,000 years in some regions. Fire frequency rose markedly across the Basin, however, during the last 2000 years, indicating an increased human presence. Fire probabilities, and thus droughts, had similar increasing trajectories between southwestern and northeastern Amazonia from 1500-1100 cal yr BP, which decoupled from 1100-740 cal yr BP, and then regained synchronicity from 740-500 cal yr BP. Fire probability declined markedly after 500 yr cal BP, coincident with European arrival to the Americas. Native populations were decimated, and fire probabilities returned to similar levels before the rise 2000 years ago. These results suggested that the synergy of humans plus drought have played a large role in historical fire regimes in Amazonian forests for the last 2000 years.
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Bregman, Tom P; Lees, Alexander C; MacGregor, Hannah E A; Darski, Bianca; de Moura, Nárgila G; Aleixo, Alexandre; Barlow, Jos; Tobias, Joseph A
2016-12-14
Vertebrates perform key roles in ecosystem processes via trophic interactions with plants and insects, but the response of these interactions to environmental change is difficult to quantify in complex systems, such as tropical forests. Here, we use the functional trait structure of Amazonian forest bird assemblages to explore the impacts of land-cover change on two ecosystem processes: seed dispersal and insect predation. We show that trait structure in assemblages of frugivorous and insectivorous birds remained stable after primary forests were subjected to logging and fire events, but that further intensification of human land use substantially reduced the functional diversity and dispersion of traits, and resulted in communities that occupied a different region of trait space. These effects were only partially reversed in regenerating secondary forests. Our findings suggest that local extinctions caused by the loss and degradation of tropical forest are non-random with respect to functional traits, thus disrupting the network of trophic interactions regulating seed dispersal by forest birds and herbivory by insects, with important implications for the structure and resilience of human-modified tropical forests. Furthermore, our results illustrate how quantitative functional traits for specific guilds can provide a range of metrics for estimating the contribution of biodiversity to ecosystem processes, and the response of such processes to land-cover change. © 2016 The Author(s).
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Bregman, Tom P.; Lees, Alexander C.; MacGregor, Hannah E. A.; Darski, Bianca; de Moura, Nárgila G.; Aleixo, Alexandre; Barlow, Jos
2016-01-01
Vertebrates perform key roles in ecosystem processes via trophic interactions with plants and insects, but the response of these interactions to environmental change is difficult to quantify in complex systems, such as tropical forests. Here, we use the functional trait structure of Amazonian forest bird assemblages to explore the impacts of land-cover change on two ecosystem processes: seed dispersal and insect predation. We show that trait structure in assemblages of frugivorous and insectivorous birds remained stable after primary forests were subjected to logging and fire events, but that further intensification of human land use substantially reduced the functional diversity and dispersion of traits, and resulted in communities that occupied a different region of trait space. These effects were only partially reversed in regenerating secondary forests. Our findings suggest that local extinctions caused by the loss and degradation of tropical forest are non-random with respect to functional traits, thus disrupting the network of trophic interactions regulating seed dispersal by forest birds and herbivory by insects, with important implications for the structure and resilience of human-modified tropical forests. Furthermore, our results illustrate how quantitative functional traits for specific guilds can provide a range of metrics for estimating the contribution of biodiversity to ecosystem processes, and the response of such processes to land-cover change. PMID:27928045
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Johnson, Michelle O; Galbraith, David; Gloor, Manuel; De Deurwaerder, Hannes; Guimberteau, Matthieu; Rammig, Anja; Thonicke, Kirsten; Verbeeck, Hans; von Randow, Celso; Monteagudo, Abel; Phillips, Oliver L; Brienen, Roel J W; Feldpausch, Ted R; Lopez Gonzalez, Gabriela; Fauset, Sophie; Quesada, Carlos A; Christoffersen, Bradley; Ciais, Philippe; Sampaio, Gilvan; Kruijt, Bart; Meir, Patrick; Moorcroft, Paul; Zhang, Ke; Alvarez-Davila, Esteban; Alves de Oliveira, Atila; Amaral, Ieda; Andrade, Ana; Aragao, Luiz E O C; Araujo-Murakami, Alejandro; Arets, Eric J M M; Arroyo, Luzmila; Aymard, Gerardo A; Baraloto, Christopher; Barroso, Jocely; Bonal, Damien; Boot, Rene; Camargo, Jose; Chave, Jerome; Cogollo, Alvaro; Cornejo Valverde, Fernando; Lola da Costa, Antonio C; Di Fiore, Anthony; Ferreira, Leandro; Higuchi, Niro; Honorio, Euridice N; Killeen, Tim J; Laurance, Susan G; Laurance, William F; Licona, Juan; Lovejoy, Thomas; Malhi, Yadvinder; Marimon, Bia; Marimon, Ben Hur; Matos, Darley C L; Mendoza, Casimiro; Neill, David A; Pardo, Guido; Peña-Claros, Marielos; Pitman, Nigel C A; Poorter, Lourens; Prieto, Adriana; Ramirez-Angulo, Hirma; Roopsind, Anand; Rudas, Agustin; Salomao, Rafael P; Silveira, Marcos; Stropp, Juliana; Ter Steege, Hans; Terborgh, John; Thomas, Raquel; Toledo, Marisol; Torres-Lezama, Armando; van der Heijden, Geertje M F; Vasquez, Rodolfo; Guimarães Vieira, Ima Cèlia; Vilanova, Emilio; Vos, Vincent A; Baker, Timothy R
2016-12-01
Understanding the processes that determine above-ground biomass (AGB) in Amazonian forests is important for predicting the sensitivity of these ecosystems to environmental change and for designing and evaluating dynamic global vegetation models (DGVMs). AGB is determined by inputs from woody productivity [woody net primary productivity (NPP)] and the rate at which carbon is lost through tree mortality. Here, we test whether two direct metrics of tree mortality (the absolute rate of woody biomass loss and the rate of stem mortality) and/or woody NPP, control variation in AGB among 167 plots in intact forest across Amazonia. We then compare these relationships and the observed variation in AGB and woody NPP with the predictions of four DGVMs. The observations show that stem mortality rates, rather than absolute rates of woody biomass loss, are the most important predictor of AGB, which is consistent with the importance of stand size structure for determining spatial variation in AGB. The relationship between stem mortality rates and AGB varies among different regions of Amazonia, indicating that variation in wood density and height/diameter relationships also influences AGB. In contrast to previous findings, we find that woody NPP is not correlated with stem mortality rates and is weakly positively correlated with AGB. Across the four models, basin-wide average AGB is similar to the mean of the observations. However, the models consistently overestimate woody NPP and poorly represent the spatial patterns of both AGB and woody NPP estimated using plot data. In marked contrast to the observations, DGVMs typically show strong positive relationships between woody NPP and AGB. Resolving these differences will require incorporating forest size structure, mechanistic models of stem mortality and variation in functional composition in DGVMs. © 2016 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.
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E. Sousa Neto; J.B. Carmo; Michael Keller; S.C. Martins; L.F. Alves; S.A. Vieira; M.C. Piccolo; P. Camargo; H.T.Z. Couto; C.A. Joly; L.A. Martinelli
2011-01-01
Soils of tropical forests are important to the global budgets of greenhouse gases. The Brazilian Atlantic Forest is the second largest tropical moist forest area of South America, after the vast Amazonian domain. This study aimed to investigate the emissions of nitrous oxide (N2O), carbon dioxide (CO2) and methane (CH4) fluxes along an altitudinal transect and the...
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Above-ground biomass and structure of 260 African tropical forests
Lewis, Simon L.; Sonké, Bonaventure; Sunderland, Terry; Begne, Serge K.; Lopez-Gonzalez, Gabriela; van der Heijden, Geertje M. F.; Phillips, Oliver L.; Affum-Baffoe, Kofi; Baker, Timothy R.; Banin, Lindsay; Bastin, Jean-François; Beeckman, Hans; Boeckx, Pascal; Bogaert, Jan; De Cannière, Charles; Chezeaux, Eric; Clark, Connie J.; Collins, Murray; Djagbletey, Gloria; Djuikouo, Marie Noël K.; Droissart, Vincent; Doucet, Jean-Louis; Ewango, Cornielle E. N.; Fauset, Sophie; Feldpausch, Ted R.; Foli, Ernest G.; Gillet, Jean-François; Hamilton, Alan C.; Harris, David J.; Hart, Terese B.; de Haulleville, Thales; Hladik, Annette; Hufkens, Koen; Huygens, Dries; Jeanmart, Philippe; Jeffery, Kathryn J.; Kearsley, Elizabeth; Leal, Miguel E.; Lloyd, Jon; Lovett, Jon C.; Makana, Jean-Remy; Malhi, Yadvinder; Marshall, Andrew R.; Ojo, Lucas; Peh, Kelvin S.-H.; Pickavance, Georgia; Poulsen, John R.; Reitsma, Jan M.; Sheil, Douglas; Simo, Murielle; Steppe, Kathy; Taedoumg, Hermann E.; Talbot, Joey; Taplin, James R. D.; Taylor, David; Thomas, Sean C.; Toirambe, Benjamin; Verbeeck, Hans; Vleminckx, Jason; White, Lee J. T.; Willcock, Simon; Woell, Hannsjorg; Zemagho, Lise
2013-01-01
We report above-ground biomass (AGB), basal area, stem density and wood mass density estimates from 260 sample plots (mean size: 1.2 ha) in intact closed-canopy tropical forests across 12 African countries. Mean AGB is 395.7 Mg dry mass ha−1 (95% CI: 14.3), substantially higher than Amazonian values, with the Congo Basin and contiguous forest region attaining AGB values (429 Mg ha−1) similar to those of Bornean forests, and significantly greater than East or West African forests. AGB therefore appears generally higher in palaeo- compared with neotropical forests. However, mean stem density is low (426 ± 11 stems ha−1 greater than or equal to 100 mm diameter) compared with both Amazonian and Bornean forests (cf. approx. 600) and is the signature structural feature of African tropical forests. While spatial autocorrelation complicates analyses, AGB shows a positive relationship with rainfall in the driest nine months of the year, and an opposite association with the wettest three months of the year; a negative relationship with temperature; positive relationship with clay-rich soils; and negative relationships with C : N ratio (suggesting a positive soil phosphorus–AGB relationship), and soil fertility computed as the sum of base cations. The results indicate that AGB is mediated by both climate and soils, and suggest that the AGB of African closed-canopy tropical forests may be particularly sensitive to future precipitation and temperature changes. PMID:23878327
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Serdukova, Larissa; Zheng, Yayun; Duan, Jinqiao; Kurths, Jürgen
2017-08-24
For the tipping elements in the Earth's climate system, the most important issue to address is how stable is the desirable state against random perturbations. Extreme biotic and climatic events pose severe hazards to tropical rainforests. Their local effects are extremely stochastic and difficult to measure. Moreover, the direction and intensity of the response of forest trees to such perturbations are unknown, especially given the lack of efficient dynamical vegetation models to evaluate forest tree cover changes over time. In this study, we consider randomness in the mathematical modelling of forest trees by incorporating uncertainty through a stochastic differential equation. According to field-based evidence, the interactions between fires and droughts are a more direct mechanism that may describe sudden forest degradation in the south-eastern Amazon. In modeling the Amazonian vegetation system, we include symmetric α-stable Lévy perturbations. We report results of stability analysis of the metastable fertile forest state. We conclude that even a very slight threat to the forest state stability represents L´evy noise with large jumps of low intensity, that can be interpreted as a fire occurring in a non-drought year. During years of severe drought, high-intensity fires significantly accelerate the transition between a forest and savanna state.
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NASA Astrophysics Data System (ADS)
Van doninck, Jasper; Tuomisto, Hanna
2017-06-01
Biodiversity mapping in extensive tropical forest areas poses a major challenge for the interpretation of Landsat images, because floristically clearly distinct forest types may show little difference in reflectance. In such cases, the effects of the bidirectional reflection distribution function (BRDF) can be sufficiently strong to cause erroneous image interpretation and classification. Since the opening of the Landsat archive in 2008, several BRDF normalization methods for Landsat have been developed. The simplest of these consist of an empirical view angle normalization, whereas more complex approaches apply the semi-empirical Ross-Li BRDF model and the MODIS MCD43-series of products to normalize directional Landsat reflectance to standard view and solar angles. Here we quantify the effect of surface anisotropy on Landsat TM/ETM+ images over old-growth Amazonian forests, and evaluate five angular normalization approaches. Even for the narrow swath of the Landsat sensors, we observed directional effects in all spectral bands. Those normalization methods that are based on removing the surface reflectance gradient as observed in each image were adequate to normalize TM/ETM+ imagery to nadir viewing, but were less suitable for multitemporal analysis when the solar vector varied strongly among images. Approaches based on the MODIS BRDF model parameters successfully reduced directional effects in the visible bands, but removed only half of the systematic errors in the infrared bands. The best results were obtained when the semi-empirical BRDF model was calibrated using pairs of Landsat observation. This method produces a single set of BRDF parameters, which can then be used to operationally normalize Landsat TM/ETM+ imagery over Amazonian forests to nadir viewing and a standard solar configuration.
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Joseph M. Wunderle Jr.; Luiza Magalli Pinto Henriques; Michael R. Willig
2006-01-01
We studied physiognomy-specific (i.e., gaps vs. understory) responses of birds to low harvest (18.7 m3/ha), reduced-impact logging by comparing 3500 mist net captures in control and cut blocks of an Amazonian terra firme forest in Brazil at 20â42 mo postharvest. Species richness did not differ significantly between control (92 species) and cut (85) forest based on...
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Regional-scale drivers of forest structure and function in northwestern Amazonia.
Higgins, Mark A; Asner, Gregory P; Anderson, Christopher B; Martin, Roberta E; Knapp, David E; Tupayachi, Raul; Perez, Eneas; Elespuru, Nydia; Alonso, Alfonso
2015-01-01
Field studies in Amazonia have found a relationship at continental scales between soil fertility and broad trends in forest structure and function. Little is known at regional scales, however, about how discrete patterns in forest structure or functional attributes map onto underlying edaphic or geological patterns. We collected airborne LiDAR (Light Detection and Ranging) data and VSWIR (Visible to Shortwave Infrared) imaging spectroscopy measurements over 600 km2 of northwestern Amazonian lowland forests. We also established 83 inventories of plant species composition and soil properties, distributed between two widespread geological formations. Using these data, we mapped forest structure and canopy reflectance, and compared them to patterns in plant species composition, soils, and underlying geology. We found that variations in soils and species composition explained up to 70% of variation in canopy height, and corresponded to profound changes in forest vertical profiles. We further found that soils and plant species composition explained more than 90% of the variation in canopy reflectance as measured by imaging spectroscopy, indicating edaphic and compositional control of canopy chemical properties. We last found that soils explained between 30% and 70% of the variation in gap frequency in these forests, depending on the height threshold used to define gaps. Our findings indicate that a relatively small number of edaphic and compositional variables, corresponding to underlying geology, may be responsible for variations in canopy structure and chemistry over large expanses of Amazonian forest.
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Silva, Daniel P.; Vilela, Bruno; De Marco, Paulo; Nemésio, André
2014-01-01
The role of past connections between the two major South American forested biomes on current species distribution has been recognized a long time ago. Climatic oscillations that further separated these biomes have promoted parapatric speciation, in which many species had their continuous distribution split, giving rise to different but related species (i.e., different potential distributions and realized niche features). The distribution of many sister species of orchid bees follow this pattern. Here, using ecological niche models and niche analyses, we (1) tested the role of ecological niche differentiation on the divergence between sister orchid-bees (genera Eulaema and Eufriesea) from the Amazon and Atlantic forests, and (2) highlighted interesting areas for new surveys. Amazonian species occupied different realized niches than their Atlantic sister species. Conversely, species of sympatric but distantly related Eulaema bees occupied similar realized niches. Amazonian species had a wide potential distribution in South America, whereas Atlantic Forest species were more limited to the eastern coast of the continent. Additionally, we identified several areas in need of future surveys. Our results show that the realized niche of Atlantic-Amazonian sister species of orchid bees, which have been previously treated as allopatric populations of three species, had limited niche overlap and similarity. These findings agree with their current taxonomy, which treats each of those populations as distinct valid species. PMID:25422941
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Amazon plant diversity revealed by a taxonomically verified species list.
Cardoso, Domingos; Särkinen, Tiina; Alexander, Sara; Amorim, André M; Bittrich, Volker; Celis, Marcela; Daly, Douglas C; Fiaschi, Pedro; Funk, Vicki A; Giacomin, Leandro L; Goldenberg, Renato; Heiden, Gustavo; Iganci, João; Kelloff, Carol L; Knapp, Sandra; Cavalcante de Lima, Haroldo; Machado, Anderson F P; Dos Santos, Rubens Manoel; Mello-Silva, Renato; Michelangeli, Fabián A; Mitchell, John; Moonlight, Peter; de Moraes, Pedro Luís Rodrigues; Mori, Scott A; Nunes, Teonildes Sacramento; Pennington, Terry D; Pirani, José Rubens; Prance, Ghillean T; de Queiroz, Luciano Paganucci; Rapini, Alessandro; Riina, Ricarda; Rincon, Carlos Alberto Vargas; Roque, Nádia; Shimizu, Gustavo; Sobral, Marcos; Stehmann, João Renato; Stevens, Warren D; Taylor, Charlotte M; Trovó, Marcelo; van den Berg, Cássio; van der Werff, Henk; Viana, Pedro Lage; Zartman, Charles E; Forzza, Rafaela Campostrini
2017-10-03
Recent debates on the number of plant species in the vast lowland rain forests of the Amazon have been based largely on model estimates, neglecting published checklists based on verified voucher data. Here we collate taxonomically verified checklists to present a list of seed plant species from lowland Amazon rain forests. Our list comprises 14,003 species, of which 6,727 are trees. These figures are similar to estimates derived from nonparametric ecological models, but they contrast strongly with predictions of much higher tree diversity derived from parametric models. Based on the known proportion of tree species in neotropical lowland rain forest communities as measured in complete plot censuses, and on overall estimates of seed plant diversity in Brazil and in the neotropics in general, it is more likely that tree diversity in the Amazon is closer to the lower estimates derived from nonparametric models. Much remains unknown about Amazonian plant diversity, but this taxonomically verified dataset provides a valid starting point for macroecological and evolutionary studies aimed at understanding the origin, evolution, and ecology of the exceptional biodiversity of Amazonian forests.
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Amazon plant diversity revealed by a taxonomically verified species list
Cardoso, Domingos; Särkinen, Tiina; Alexander, Sara; Amorim, André M.; Bittrich, Volker; Celis, Marcela; Daly, Douglas C.; Fiaschi, Pedro; Funk, Vicki A.; Giacomin, Leandro L.; Heiden, Gustavo; Iganci, João; Kelloff, Carol L.; Knapp, Sandra; Cavalcante de Lima, Haroldo; Machado, Anderson F. P.; dos Santos, Rubens Manoel; Mello-Silva, Renato; Michelangeli, Fabián A.; Mitchell, John; Moonlight, Peter; de Moraes, Pedro Luís Rodrigues; Mori, Scott A.; Nunes, Teonildes Sacramento; Pennington, Terry D.; Pirani, José Rubens; Prance, Ghillean T.; de Queiroz, Luciano Paganucci; Rapini, Alessandro; Rincon, Carlos Alberto Vargas; Roque, Nádia; Shimizu, Gustavo; Sobral, Marcos; Stehmann, João Renato; Stevens, Warren D.; Taylor, Charlotte M.; Trovó, Marcelo; van den Berg, Cássio; van der Werff, Henk; Viana, Pedro Lage; Zartman, Charles E.; Forzza, Rafaela Campostrini
2017-01-01
Recent debates on the number of plant species in the vast lowland rain forests of the Amazon have been based largely on model estimates, neglecting published checklists based on verified voucher data. Here we collate taxonomically verified checklists to present a list of seed plant species from lowland Amazon rain forests. Our list comprises 14,003 species, of which 6,727 are trees. These figures are similar to estimates derived from nonparametric ecological models, but they contrast strongly with predictions of much higher tree diversity derived from parametric models. Based on the known proportion of tree species in neotropical lowland rain forest communities as measured in complete plot censuses, and on overall estimates of seed plant diversity in Brazil and in the neotropics in general, it is more likely that tree diversity in the Amazon is closer to the lower estimates derived from nonparametric models. Much remains unknown about Amazonian plant diversity, but this taxonomically verified dataset provides a valid starting point for macroecological and evolutionary studies aimed at understanding the origin, evolution, and ecology of the exceptional biodiversity of Amazonian forests. PMID:28923966
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Production of nitrous oxide and consumption of methane by forest soils
NASA Technical Reports Server (NTRS)
Keller, M.; Wofsy, S. C.; Kaplan, W. A.; Mcelroy, M. B.; Goreau, T. J.
1983-01-01
Soils in an Amazonian rainforest are observed to release N2O at a rate larger than the global mean by about a factor of 20. Emissions from a New England hardwood forest are approximately 30 times smaller then Brazilian values. Atmospheric methane is consumed by soils in both systems. Tropical forests would provide a major source of atmospheric N2O if the Brazilian results are representative.
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Rapid decay of tree-community composition in Amazonian forest fragments
Laurance, William F.; Nascimento, Henrique E. M.; Laurance, Susan G.; Andrade, Ana; Ribeiro, José E. L. S.; Giraldo, Juan Pablo; Lovejoy, Thomas E.; Condit, Richard; Chave, Jerome; Harms, Kyle E.; D'Angelo, Sammya
2006-01-01
Forest fragmentation is considered a greater threat to vertebrates than to tree communities because individual trees are typically long-lived and require only small areas for survival. Here we show that forest fragmentation provokes surprisingly rapid and profound alterations in Amazonian tree-community composition. Results were derived from a 22-year study of exceptionally diverse tree communities in 40 1-ha plots in fragmented and intact forests, which were sampled repeatedly before and after fragment isolation. Within these plots, trajectories of change in abundance were assessed for 267 genera and 1,162 tree species. Abrupt shifts in floristic composition were driven by sharply accelerated tree mortality and recruitment within ≈100 m of fragment margins, causing rapid species turnover and population declines or local extinctions of many large-seeded, slow-growing, and old-growth taxa; a striking increase in a smaller set of disturbance-adapted and abiotically dispersed species; and significant shifts in tree size distributions. Even among old-growth trees, species composition in fragments is being restructured substantially, with subcanopy species that rely on animal seed-dispersers and have obligate outbreeding being the most strongly disadvantaged. These diverse changes in tree communities are likely to have wide-ranging impacts on forest architecture, canopy-gap dynamics, plant–animal interactions, and forest carbon storage. PMID:17148598
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Continuous soil carbon storage of old permanent pastures in Amazonia.
Stahl, Clément; Fontaine, Sébastien; Klumpp, Katja; Picon-Cochard, Catherine; Grise, Marcia Mascarenhas; Dezécache, Camille; Ponchant, Lise; Freycon, Vincent; Blanc, Lilian; Bonal, Damien; Burban, Benoit; Soussana, Jean-François; Blanfort, Vincent
2017-08-01
Amazonian forests continuously accumulate carbon (C) in biomass and in soil, representing a carbon sink of 0.42-0.65 GtC yr -1 . In recent decades, more than 15% of Amazonian forests have been converted into pastures, resulting in net C emissions (~200 tC ha -1 ) due to biomass burning and litter mineralization in the first years after deforestation. However, little is known about the capacity of tropical pastures to restore a C sink. Our study shows in French Amazonia that the C storage observed in native forest can be partly restored in old (≥24 year) tropical pastures managed with a low stocking rate (±1 LSU ha -1 ) and without the use of fire since their establishment. A unique combination of a large chronosequence study and eddy covariance measurements showed that pastures stored between -1.27 ± 0.37 and -5.31 ± 2.08 tC ha -1 yr -1 while the nearby native forest stored -3.31 ± 0.44 tC ha -1 yr -1 . This carbon is mainly sequestered in the humus of deep soil layers (20-100 cm), whereas no C storage was observed in the 0- to 20-cm layer. C storage in C4 tropical pasture is associated with the installation and development of C3 species, which increase either the input of N to the ecosystem or the C:N ratio of soil organic matter. Efforts to curb deforestation remain an obvious priority to preserve forest C stocks and biodiversity. However, our results show that if sustainable management is applied in tropical pastures coming from deforestation (avoiding fires and overgrazing, using a grazing rotation plan and a mixture of C3 and C4 species), they can ensure a continuous C storage, thereby adding to the current C sink of Amazonian forests. © 2016 John Wiley & Sons Ltd.
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Temporal Decay in Timber Species Composition and Value in Amazonian Logging Concessions.
Richardson, Vanessa A; Peres, Carlos A
2016-01-01
Throughout human history, slow-renewal biological resource populations have been predictably overexploited, often to the point of economic extinction. We assess whether and how this has occurred with timber resources in the Brazilian Amazon. The asynchronous advance of industrial-scale logging frontiers has left regional-scale forest landscapes with varying histories of logging. Initial harvests in unlogged forests can be highly selective, targeting slow-growing, high-grade, shade-tolerant hardwood species, while later harvests tend to focus on fast-growing, light-wooded, long-lived pioneer trees. Brazil accounts for 85% of all native neotropical forest roundlog production, and the State of Pará for almost half of all timber production in Brazilian Amazonia, the largest old-growth tropical timber reserve controlled by any country. Yet the degree to which timber harvests beyond the first-cut can be financially profitable or demographically sustainable remains poorly understood. Here, we use data on legally planned logging of ~17.3 million cubic meters of timber across 314 species extracted from 824 authorized harvest areas in private and community-owned forests, 446 of which reported volumetric composition data by timber species. We document patterns of timber extraction by volume, species composition, and monetary value along aging eastern Amazonian logging frontiers, which are then explained on the basis of historical and environmental variables. Generalized linear models indicate that relatively recent logging operations farthest from heavy-traffic roads are the most selective, concentrating gross revenues on few high-value species. We find no evidence that the post-logging timber species composition and total value of forest stands recovers beyond the first-cut, suggesting that the commercially most valuable timber species become predictably rare or economically extinct in old logging frontiers. In avoiding even more destructive land-use patterns, managing yields of selectively-logged forests is crucial for the long-term integrity of forest biodiversity and financial viability of local industries. The logging history of eastern Amazonian old-growth forests likely mirrors unsustainable patterns of timber depletion over time in Brazil and other tropical countries.
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Temporal Decay in Timber Species Composition and Value in Amazonian Logging Concessions
Peres, Carlos A.
2016-01-01
Throughout human history, slow-renewal biological resource populations have been predictably overexploited, often to the point of economic extinction. We assess whether and how this has occurred with timber resources in the Brazilian Amazon. The asynchronous advance of industrial-scale logging frontiers has left regional-scale forest landscapes with varying histories of logging. Initial harvests in unlogged forests can be highly selective, targeting slow-growing, high-grade, shade-tolerant hardwood species, while later harvests tend to focus on fast-growing, light-wooded, long-lived pioneer trees. Brazil accounts for 85% of all native neotropical forest roundlog production, and the State of Pará for almost half of all timber production in Brazilian Amazonia, the largest old-growth tropical timber reserve controlled by any country. Yet the degree to which timber harvests beyond the first-cut can be financially profitable or demographically sustainable remains poorly understood. Here, we use data on legally planned logging of ~17.3 million cubic meters of timber across 314 species extracted from 824 authorized harvest areas in private and community-owned forests, 446 of which reported volumetric composition data by timber species. We document patterns of timber extraction by volume, species composition, and monetary value along aging eastern Amazonian logging frontiers, which are then explained on the basis of historical and environmental variables. Generalized linear models indicate that relatively recent logging operations farthest from heavy-traffic roads are the most selective, concentrating gross revenues on few high-value species. We find no evidence that the post-logging timber species composition and total value of forest stands recovers beyond the first-cut, suggesting that the commercially most valuable timber species become predictably rare or economically extinct in old logging frontiers. In avoiding even more destructive land-use patterns, managing yields of selectively-logged forests is crucial for the long-term integrity of forest biodiversity and financial viability of local industries. The logging history of eastern Amazonian old-growth forests likely mirrors unsustainable patterns of timber depletion over time in Brazil and other tropical countries. PMID:27410029
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Falling palm fronds structure amazonian rainforest sapling communities.
Peters, Halton A; Pauw, Anton; Silman, Miles R; Terborgh, John W
2004-08-07
The senescence and loss of photosynthetic and support structures is a nearly universal aspect of tree life history, and can be a major source of disturbance in forest understoreys, but the ability of falling canopy debris in determining the stature and composition of understorey communities seems not to have been documented. In this study, we show that senescent fronds of the palm Iriartea deltoidea cause substantial disturbance in tropical forest sapling communities. This disturbance influences the species composition of the canopy and subcanopy by acting as an ecological filter, favouring sapling species with characteristics conducive to recovery after physical damage. The scale of this dominance suggests that falling I. deltoidea debris may be influencing sapling community structure and species composition in Amazonian rainforests over very large spatial scales.
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Hines, James; Powell, Luke L.; Wolfe, Jared D.; Johnson, Erik l.; Nichols, James D.; Stouffer, Phillip C.
2015-01-01
Given rates of deforestation, disturbance, and secondary forest accumulation in tropical rainforests, there is a great need to quantify habitat use and movement among different habitats. This need is particularly pronounced for animals most sensitive to disturbance, such as insectivorous understory birds. Here we use multistate capture–recapture models with radiotelemetry data to determine the successional stage at which within-day movement probabilities of Amazonian birds in secondary forest are similar to those in primary forest. We radio-tracked three common understory insectivore species in primary and secondary forest at the Biological Dynamics of Forest Fragments project near Manaus, Brazil: two woodcreepers, Glyphorynchus spirurus (n = 19) andXiphorhynchus pardalotus (n = 18), and the terrestrial antthrush Formicarius colma(n = 19). Forest age was a strong predictor of fidelity to a given habitat. All three species showed greater fidelity to primary forest than to 8–14-year-old secondary forest, indicating the latter’s relatively poor quality. The two woodcreeper species used 12–18-year-old secondary forest in a manner comparable to continuous forest, but F. colmaavoided moving even to 27–31-year-old secondary forest—the oldest at our site. Our results suggest that managers concerned with less sensitive species can assume that forest reserves connected by 12–18-year-old secondary forest corridors are effectively connected. On the other hand, >30 years are required after land abandonment before secondary forest serves as a primary forest-like conduit for movement by F. colma; more sensitive terrestrial insectivores may take longer still.
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Methane flux from the central Amazonian floodplain
NASA Technical Reports Server (NTRS)
Bartlett, Karen B.; Crill, Patrick M.; Sebacher, Daniel I.; Harriss, Robert C.; Wilson, John O.
1988-01-01
A total of 186 methane measurements from the three primary Amazon floodplain environments of open water lakes, flood forests, and floating grass mats were made over the period 18 July through 2 September 1985. These data indicate that emissions were lowest over open water lakes. Flux from flooded forests and grass mats was significantly higher. At least three transport processes contribute to tropospheric emissions: ebullition from sediments, diffusion along the concentration gradient from sediment to overlaying water to air, and transport through the roots and stems of aquatic plants. Measurements indicate that the first two of these processes are most significant. It was estimated that on the average bubbling makes up 49 percent of the flux from open water, 54 percent of that from flooded forests, and 64 percent of that from floating mats. If the measurements were applied to the entire Amazonian floodplain, it is calculated that the region could supply up to 12 percent of the estimated global natural sources of methane.
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Geological control of floristic composition in Amazonian forests
Higgins, Mark A; Ruokolainen, Kalle; Tuomisto, Hanna; Llerena, Nelly; Cardenas, Glenda; Phillips, Oliver L; Vásquez, Rodolfo; Räsänen, Matti
2011-01-01
Aim Conservation and land-use planning require accurate maps of patterns in species composition and an understanding of the factors that control them. Substantial doubt exists, however, about the existence and determinants of large-area floristic divisions in Amazonia. Here we ask whether Amazonian forests are partitioned into broad-scale floristic units on the basis of geological formations and their edaphic properties. Location Western and central Amazonia. Methods We used Landsat imagery and Shuttle Radar Topography Mission (SRTM) digital elevation data to identify a possible floristic and geological discontinuity of over 300 km in northern Peru. We then used plant inventories and soil sampling to document changes in species composition and soil properties across this boundary. Data were obtained from 138 sites distributed along more than 450 km of road and river. On the basis of our findings, we used broad-scale Landsat and SRTM mosaics to identify similar patterns across western and central Amazonia. Results The discontinuity identified in Landsat and SRTM data corresponded to a 15-fold change in soil cation concentrations and an almost total change in plant species composition. This discontinuity appears to be caused by the widespread removal of cation-poor surface sediments by river incision to expose cation-rich sediments beneath. Examination of broad-scale Landsat and SRTM mosaics indicated that equivalent processes have generated a north–south discontinuity of over 1500 km in western Brazil. Due to similarities with our study area, we suggest that this discontinuity represents a chemical and ecological limit between western and central Amazonia. Main conclusions Our findings suggest that Amazonian forests are partitioned into large-area units on the basis of geological formations and their edaphic properties. The evolution of these units through geological time may provide a general mechanism for biotic diversification in Amazonia. These compositional units, moreover, may correspond to broad-scale functional units. The existence of large-area compositional and functional units would suggest that protected-area, carbon sequestration, and other land-use strategies in Amazonia be implemented on a region-by-region basis. The methods described here can be used to map these patterns, and thus enable effective conservation and management of Amazonian forests. PMID:22247585
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NASA Astrophysics Data System (ADS)
Castanho, A. D.; Zhang, K.; Coe, M. T.; Costa, M. H.; Moorcroft, P. R.
2012-12-01
Field observations from undisturbed old-growth Amazonian forest plots have recently reported on the temporal variation of many of the physical and chemical characteristics such as: physiological properties of leaves, above ground live biomass, above ground productivity, mortality and turnover rates. However, although this variation has been measured, it is still not well understood what mechanisms control the observed temporal variability. The observed changes in time are believed to be a result of a combination of increasing atmospheric CO2 concentration, climate variability, recovery from natural disturbance (drought, wind blow, flood), and increase of nutrient availability. The time and spatial variability of the fertilization effect of CO2 on above ground biomass will be explored in more detail in this work. A precise understanding of the CO2 effect on the vegetation is essential for an accurate prediction of the future response of the forest to climate change. To address this issue we simultaneously explore the effects of climate variability, historical CO2 and land-use change on total biomass and productivity using two different Dynamic Global Vegetation Models (DGVM). We use the Integrated Biosphere Simulator (IBIS) and the Ecosystem Demography Model 2.1 (ED2.1). Using land use changes database from 1700 - 2008 we reconstruct the total carbon balance in the Amazonian forest in space and time and present how the models predict the forest as carbon sink or source and explore why the model and field data diverge from each other. From 1970 to 2005 the Amazonian forest has been exposed to an increase of approximately 50 ppm in the atmospheric CO2 concentration. Preliminary analyses with the IBIS and ED2.1 dynamic vegetation model shows the CO2 fertilization effect could account for an increase in above ground biomass of 0.03 and 0.04 kg-C/m2/yr on average for the Amazon basin, respectively. The annual biomass change varies temporally and spatially from about 0.01 - 0.08 Kg-C/m2/yr, indicating a significant combined effect of the physical environment and climatological variability. The change in biomass due to CO2 fertilization in this study is comparable to the lower limit of the change that has been observed in the field (0.04 - 0.085 kg-C/m2/yr), which suggests that other factors must also be considered to explain the total amount of biomass change observed in the field.
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Wildfires in bamboo-dominated Amazonian forest: impacts on above-ground biomass and biodiversity.
Barlow, Jos; Silveira, Juliana M; Mestre, Luiz A M; Andrade, Rafael B; Camacho D'Andrea, Gabriela; Louzada, Julio; Vaz-de-Mello, Fernando Z; Numata, Izaya; Lacau, Sébastien; Cochrane, Mark A
2012-01-01
Fire has become an increasingly important disturbance event in south-western Amazonia. We conducted the first assessment of the ecological impacts of these wildfires in 2008, sampling forest structure and biodiversity along twelve 500 m transects in the Chico Mendes Extractive Reserve, Acre, Brazil. Six transects were placed in unburned forests and six were in forests that burned during a series of forest fires that occurred from August to October 2005. Normalized Burn Ratio (NBR) calculations, based on Landsat reflectance data, indicate that all transects were similar prior to the fires. We sampled understorey and canopy vegetation, birds using both mist nets and point counts, coprophagous dung beetles and the leaf-litter ant fauna. Fire had limited influence upon either faunal or floral species richness or community structure responses, and stems <10 cm DBH were the only group to show highly significant (p = 0.001) community turnover in burned forests. Mean aboveground live biomass was statistically indistinguishable in the unburned and burned plots, although there was a significant increase in the total abundance of dead stems in burned plots. Comparisons with previous studies suggest that wildfires had much less effect upon forest structure and biodiversity in these south-western Amazonian forests than in central and eastern Amazonia, where most fire research has been undertaken to date. We discuss potential reasons for the apparent greater resilience of our study plots to wildfire, examining the role of fire intensity, bamboo dominance, background rates of disturbance, landscape and soil conditions.
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Wildfires in Bamboo-Dominated Amazonian Forest: Impacts on Above-Ground Biomass and Biodiversity
Barlow, Jos; Silveira, Juliana M.; Mestre, Luiz A. M.; Andrade, Rafael B.; Camacho D'Andrea, Gabriela; Louzada, Julio; Vaz-de-Mello, Fernando Z.; Numata, Izaya; Lacau, Sébastien; Cochrane, Mark A.
2012-01-01
Fire has become an increasingly important disturbance event in south-western Amazonia. We conducted the first assessment of the ecological impacts of these wildfires in 2008, sampling forest structure and biodiversity along twelve 500 m transects in the Chico Mendes Extractive Reserve, Acre, Brazil. Six transects were placed in unburned forests and six were in forests that burned during a series of forest fires that occurred from August to October 2005. Normalized Burn Ratio (NBR) calculations, based on Landsat reflectance data, indicate that all transects were similar prior to the fires. We sampled understorey and canopy vegetation, birds using both mist nets and point counts, coprophagous dung beetles and the leaf-litter ant fauna. Fire had limited influence upon either faunal or floral species richness or community structure responses, and stems <10 cm DBH were the only group to show highly significant (p = 0.001) community turnover in burned forests. Mean aboveground live biomass was statistically indistinguishable in the unburned and burned plots, although there was a significant increase in the total abundance of dead stems in burned plots. Comparisons with previous studies suggest that wildfires had much less effect upon forest structure and biodiversity in these south-western Amazonian forests than in central and eastern Amazonia, where most fire research has been undertaken to date. We discuss potential reasons for the apparent greater resilience of our study plots to wildfire, examining the role of fire intensity, bamboo dominance, background rates of disturbance, landscape and soil conditions. PMID:22428035
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Regional-Scale Drivers of Forest Structure and Function in Northwestern Amazonia
Higgins, Mark A.; Asner, Gregory P.; Anderson, Christopher B.; Martin, Roberta E.; Knapp, David E.; Tupayachi, Raul; Perez, Eneas; Elespuru, Nydia; Alonso, Alfonso
2015-01-01
Field studies in Amazonia have found a relationship at continental scales between soil fertility and broad trends in forest structure and function. Little is known at regional scales, however, about how discrete patterns in forest structure or functional attributes map onto underlying edaphic or geological patterns. We collected airborne LiDAR (Light Detection and Ranging) data and VSWIR (Visible to Shortwave Infrared) imaging spectroscopy measurements over 600 km2 of northwestern Amazonian lowland forests. We also established 83 inventories of plant species composition and soil properties, distributed between two widespread geological formations. Using these data, we mapped forest structure and canopy reflectance, and compared them to patterns in plant species composition, soils, and underlying geology. We found that variations in soils and species composition explained up to 70% of variation in canopy height, and corresponded to profound changes in forest vertical profiles. We further found that soils and plant species composition explained more than 90% of the variation in canopy reflectance as measured by imaging spectroscopy, indicating edaphic and compositional control of canopy chemical properties. We last found that soils explained between 30% and 70% of the variation in gap frequency in these forests, depending on the height threshold used to define gaps. Our findings indicate that a relatively small number of edaphic and compositional variables, corresponding to underlying geology, may be responsible for variations in canopy structure and chemistry over large expanses of Amazonian forest. PMID:25793602
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Amazonian landscapes and the bias in field studies of forest structure and biomass.
Marvin, David C; Asner, Gregory P; Knapp, David E; Anderson, Christopher B; Martin, Roberta E; Sinca, Felipe; Tupayachi, Raul
2014-12-02
Tropical forests convert more atmospheric carbon into biomass each year than any terrestrial ecosystem on Earth, underscoring the importance of accurate tropical forest structure and biomass maps for the understanding and management of the global carbon cycle. Ecologists have long used field inventory plots as the main tool for understanding forest structure and biomass at landscape-to-regional scales, under the implicit assumption that these plots accurately represent their surrounding landscape. However, no study has used continuous, high-spatial-resolution data to test whether field plots meet this assumption in tropical forests. Using airborne LiDAR (light detection and ranging) acquired over three regions in Peru, we assessed how representative a typical set of field plots are relative to their surrounding host landscapes. We uncovered substantial mean biases (9-98%) in forest canopy structure (height, gaps, and layers) and aboveground biomass in both lowland Amazonian and montane Andean landscapes. Moreover, simulations reveal that an impractical number of 1-ha field plots (from 10 to more than 100 per landscape) are needed to develop accurate estimates of aboveground biomass at landscape scales. These biases should temper the use of plots for extrapolations of forest dynamics to larger scales, and they demonstrate the need for a fundamental shift to high-resolution active remote sensing techniques as a primary sampling tool in tropical forest biomass studies. The potential decrease in the bias and uncertainty of remotely sensed estimates of forest structure and biomass is a vital step toward successful tropical forest conservation and climate-change mitigation policy.
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Drought Legacy and the Impacts on the Amazon Forest Carbon Exchange
NASA Astrophysics Data System (ADS)
Saatchi, S. S.
2015-12-01
Sassan Saatchi1,2, Yifan Yu1, Xiang Xu2, Luiz Aragao3, Liana Anderson31Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA2Institute of Environment and Sustainability, University of California, Los Angeles, CA 90045. USA3 Remote Sensing Division, National Institute for Space Research, São José dos Campos, Brazil, 12227-010, BrazilRecent Amazonian droughts have drawn attention to the vulnerability of tropical forests to climate perturbations. Ground and satellite observations of 2005 and 2010 mega-droughts have shown an increase in fire occurrence and tree mortality during the period of drought. Here, we use a combination of satellite observations over a period of about 15 years to examine the legacy of the droughts in terms of impacts on the ecological structure and function of the forests in years following the droughts and the subsequent carbon exchange. Using data from microwave satellite sensors of rainfall, canopy backscatter (2000-2014) and GRACE and GOSAT, we show that the 2005 drought has a legacy of 2-5 years in western Amazonia, by increasing the disturbance in canopy trees and impacting the gross primary production of the forest significantly. Amazonian forests, particularly in the southern region were again impacted by the 2010 mega-drought, causing a legacy of 2-4 years with potential decrease in GPP and productivity observed by GOSAT fluorescence. The persistent of low canopy water content observed by a joint QSCAT and OceanSAT observations were linked to a delay in recharging of the hydrological system observed by GRACE over a period of 2-5 years. The results suggest that Amazonian forests with distinct dry seasons in southern and western regions of the basin are potentially more vulnerable to droughts compared to regions with less seasonality. The long recovery time from the 2005 and 2010 droughts suggests that the occurence of droughts in Amazonia at 5-10 year frequency may lead to long-term alteration of the forest structure and function. Keywords: Amazonia, drought, carbon exchange, biomass loss, GPP
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Drought sensitivity of Amazonian carbon balance revealed by atmospheric measurements
NASA Astrophysics Data System (ADS)
Gatti, L. V.; Gloor, M.; Miller, J. B.; Doughty, C. E.; Malhi, Y.; Domingues, L. G.; Basso, L. S.; Martinewski, A.; Correia, C. S. C.; Borges, V. F.; Freitas, S.; Braz, R.; Anderson, L. O.; Rocha, H.; Grace, J.; Phillips, O. L.; Lloyd, J.
2014-02-01
Feedbacks between land carbon pools and climate provide one of the largest sources of uncertainty in our predictions of global climate. Estimates of the sensitivity of the terrestrial carbon budget to climate anomalies in the tropics and the identification of the mechanisms responsible for feedback effects remain uncertain. The Amazon basin stores a vast amount of carbon, and has experienced increasingly higher temperatures and more frequent floods and droughts over the past two decades. Here we report seasonal and annual carbon balances across the Amazon basin, based on carbon dioxide and carbon monoxide measurements for the anomalously dry and wet years 2010 and 2011, respectively. We find that the Amazon basin lost 0.48+/-0.18 petagrams of carbon per year (PgCyr-1) during the dry year but was carbon neutral (0.06+/-0.1PgCyr-1) during the wet year. Taking into account carbon losses from fire by using carbon monoxide measurements, we derived the basin net biome exchange (that is, the carbon flux between the non-burned forest and the atmosphere) revealing that during the dry year, vegetation was carbon neutral. During the wet year, vegetation was a net carbon sink of 0.25+/-0.14PgCyr-1, which is roughly consistent with the mean long-term intact-forest biomass sink of 0.39+/-0.10PgCyr-1 previously estimated from forest censuses. Observations from Amazonian forest plots suggest the suppression of photosynthesis during drought as the primary cause for the 2010 sink neutralization. Overall, our results suggest that moisture has an important role in determining the Amazonian carbon balance. If the recent trend of increasing precipitation extremes persists, the Amazon may become an increasing carbon source as a result of both emissions from fires and the suppression of net biome exchange by drought.
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Extractive reserves in Brazilian Amazonia
DOE Office of Scientific and Technical Information (OSTI.GOV)
Fearnside, P.M
1989-06-01
In 1985 an opportunity arose for maintaining tracts of Amazonian forest under sustainable use. Brazil's National Council of Rubber Tappers and the Rural Worker's Union proposed the creation of a set of reserves of a new type, called extractive reserves. The first six are being established in one of the Brazilian states most threatened by deforestatation. The creation of extractive reserves grants legal protection to forest land traditionally used by rubber tappers, Brazil-nut gatherers, and other extractivists. The term extrativismo (extractivism) in Brazil refers to removing nontimber forest products, such as latex, resins, and nuts, without felling the trees. Approximatelymore » 30 products are collected for commercial sale. Many more types of forest materials are gathered, for example as food and medicines, for the extractivists' own use. The reserve proposal is attractive for several reasons related to social problems. It allows the rubber tappers to continue their livelihood rather than be expelled by deforestation. However, it is unlikely that sufficient land will be set aside as extractive reserves to employ all the tappers. Displaced rubber tappers already swell the ranks of urban slum dwellers in Brazil's Amazonian cities, and they have become refugees to continue their profession in the forests of neighboring countries, such as Bolivia.« less
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Small mammal responses to Amazonian forest islands are modulated by their forest dependence.
Palmeirim, Ana Filipa; Benchimol, Maíra; Vieira, Marcus Vinícius; Peres, Carlos A
2018-05-01
Hydroelectric dams have induced widespread loss, fragmentation and degradation of terrestrial habitats in lowland tropical forests. Yet their ecological impacts have been widely neglected, particularly in developing countries, which are currently earmarked for exponential hydropower development. Here we assess small mammal assemblage responses to Amazonian forest habitat insularization induced by the 28-year-old Balbina Hydroelectric Dam. We sampled small mammals on 25 forest islands (0.83-1466 ha) and four continuous forest sites in the mainland to assess the overall community structure and species-specific responses to forest insularization. We classified all species according to their degree of forest-dependency using a multi-scale approach, considering landscape, patch and local habitat characteristics. Based on 65,520 trap-nights, we recorded 884 individuals of at least 22 small mammal species. Species richness was best predicted by island area and isolation, with small islands (< 15 ha) harbouring an impoverished nested subset of species (mean ± SD: 2.6 ± 1.3 species), whereas large islands (> 200 ha; 10.8 ± 1.3 species) and continuous forest sites (∞ ha; 12.5 ± 2.5 species) exhibited similarly high species richness. Forest-dependent species showed higher local extinction rates and were often either absent or persisted at low abundances on small islands, where non-forest-dependent species became hyper-abundant. Species capacity to use non-forest habitat matrices appears to dictate small mammal success in small isolated islands. We suggest that ecosystem functioning may be highly disrupted on small islands, which account for 62.7% of all 3546 islands in the Balbina Reservoir.
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Herbivores limit the population size of big-leaf mahogany trees in an Amazonian forest
Julian M. Norghauer; Christopher M. Free; R. Matthew Landis; James Grogan; Jay R. Malcolm; Sean C. Thomas
2015-01-01
The Janzen -- Connell hypothesis proposes that specialized herbivores maintain high numbers of tree species in tropical forests by restricting adult recruitment so that host populations remain at low densities. We tested this prediction for the large timber tree species, Swietenia macrophylla, whose seeds and seedlings are preyed upon by small mammals and a host-...
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Understorey fire propagation and tree mortality on adjacent areas to an Amazonian deforestation fire
J.A. Carvalho; C.A. Gurgel Veras; E.C. Alvarado; D.V. Sandberg; S.J. Leite; R. Gielow; E.R.C. Rabelo; J.C. Santos
2010-01-01
Fire characteristics in tropical ecosystems are poorly documented quantitatively in the literature. This paper describes an understorey fire propagating across the edges of a biomass burn of a cleared primary forest. The experiment was carried out in 2001 in the Amazon forest near Alta Floresta, state of Mato Grosso, Brazil, as part of biomass burning experiments...
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Effects of reduced impact logging on bat biodiversity in terra firme forest of lowland Amazonia.
Ivan Castro-Arellanos; Steven J. Presley; Luis Nelio Saldanha; Michael R. Willig; Joseph M. Wunderle Jr.
2007-01-01
Timber harvest is one of the main causes of degradation of Amazonian tropical forests, where bats represent important components of biodiversity. In addition, bats may represent keystone taxa in the Neotropics, as they are primary agents of pollination and seed dispersal for many pioneer plants. We assessed the impact of low harvest (18m3/ha),...
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Mark Schulze; James Grogan; Chris Uhl; Marco Lentini; Edson Vidal
2008-01-01
Prized for their dense, rot-resistant wood, Tabebuia impetiginosa and T. serratifolia (vernacular name = ipeË ) are among the most valuable Amazonian timbers. We analyzed the geographical extent, spread and trajectory of ipeË logging in Brazilian Amazonia, and evaluated harvest pressure on this forest resource. We also examine Tabebuia population response to reduced-...
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Retention of phosphorus in highly weathered soils under a lowland Amazonian forest ecosystem
M. E. McGroddy; W. L. Silver; Jr. de Oliveira; W. Z. de Mello; M. Keller
2008-01-01
The low available phosphorus (P) pools typical of highly weathered tropical forest soils are thought to result from a combination of export of phosphorus via erosion and leaching as well as chemical reactions resulting in physically and chemically protected P compounds. Despite the low apparent P availability, these soils support some of the highest terrestrial net...
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Poor Prospects for Avian Biodiversity in Amazonian Oil Palm
Lees, Alexander C.; Vieira, Ima C. G.
2015-01-01
Expansion of oil palm plantations across the humid tropics has precipitated massive loss of tropical forest habitats and their associated speciose biotas. Oil palm plantation monocultures have been identified as an emerging threat to Amazonian biodiversity, but there are no quantitative studies exploring the impact of these plantations on the biome’s biota. Understanding these impacts is extremely important given the rapid projected expansion of oil palm cultivation in the basin. Here we investigate the biodiversity value of oil palm plantations in comparison with other dominant regional land-uses in Eastern Amazonia. We carried out bird surveys in oil palm plantations of varying ages, primary and secondary forests, and cattle pastures. We found that oil palm plantations retained impoverished avian communities with a similar species composition to pastures and agrarian land-uses and did not offer habitat for most forest-associated species, including restricted range species and species of conservation concern. On the other hand, the forests that the oil palm companies are legally obliged to protect hosted a relatively species-rich community including several globally-threatened bird species. We consider oil palm to be no less detrimental to regional biodiversity than other agricultural land-uses and that political pressure exerted by large landowners to allow oil palm to count as a substitute for native forest vegetation in private landholdings with forest restoration deficits would have dire consequences for regional biodiversity. PMID:25955243
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Ratter, J A; Askew, G P; Montgomery, R F; Gifford, D R
1978-12-04
The vegetation of the well drained soils along the Suiá--Missu road in the Serra do Roncador region of NE Mato Grosso is Evergreen Seasonal forest of Amazonian type. The area lies close to the meeting place of the Amazonian forest (the hylaea) and the cerrado (savanna) formation of Central Brazil. The structure of the forest is simple: the canopy is at about 18--23 m, and is exceeded by a few scattered emergents; no recognizable strata can be distinguished among the understorey trees and the shrub and herb layers are sparse. Table 1 lists the most important species and gives information on stratification and general distribution. Most of the species appear to have a hylaean centre of distribution but extend into other vegetation types. The forest differs from related communities which lie closer to the cerrado/forest boundary in its greater height and luxuriance, the presence of additional tall tree species, and the great reduction in abundance of a cerrado floristic element. A survey on the Xavantina--São Felix road allowed us to extend previous observations on the distance to which the cerrado tree Pterodon pubescens extends into the forest. The results obtained indicate a considerable extension of forest into cerrado during the life of an individual tree. A characteristic low forest occurs in the flood plain of the Rio Suiá--Missu while Swampy Gallery forests occur on permanently waterlogged soils around the headwaters of streams. The well drained soils of the Suiá--Missu forest are very uniform, deep latosols (oxisols) of very dystrophic nature with pH (in water) between 4.0 and 5.0 (see table 2, p. 203).
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Taxonomic and functional composition of arthropod assemblages across contrasting Amazonian forests.
Lamarre, Greg P A; Hérault, Bruno; Fine, Paul V A; Vedel, Vincent; Lupoli, Roland; Mesones, Italo; Baraloto, Christopher
2016-01-01
Arthropods represent most of global biodiversity, with the highest diversity found in tropical rain forests. Nevertheless, we have a very incomplete understanding of how tropical arthropod communities are assembled. We conducted a comprehensive mass sampling of arthropod communities within three major habitat types of lowland Amazonian rain forest, including terra firme clay, white-sand and seasonally flooded forests in Peru and French Guiana. We examined how taxonomic and functional composition (at the family level) differed across these habitat types in the two regions. The overall arthropod community composition exhibited strong turnover among habitats and between regions. In particular, seasonally flooded forest habitats of both regions comprised unique assemblages. Overall, 17·7% (26 of 147) of arthropod families showed significant preferences for a particular habitat type. We present a first reproducible arthropod functional classification among the 147 taxa based on similarity among 21 functional traits describing feeding source, major mouthparts and microhabitats inhabited by each taxon. We identified seven distinct functional groups whose relative abundance contrasted strongly across the three habitats, with sap and leaf feeders showing higher abundances in terra firme clay forest. Our novel arthropod functional classification provides an important complement to link these contrasting patterns of composition to differences in forest functioning across geographical and environmental gradients. This study underlines that both environment and biogeographical processes are responsible for driving arthropod taxonomic composition while environmental filtering is the main driver of the variance in functional composition. © 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society.
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Amazonian foods and implications for human biology.
Dufour, Darna L; Piperata, Barbara A; Murrieta, Rui S S; Wilson, Warren M; Williams, Drake D
2016-07-01
Diets of subsistence-based Amazonian populations have been linked to local resources, but are changing with market penetration. To review the available data on traditional Amazonian foods and diets and evaluate their implications for human biology as a step toward understanding nutrition transitions in the region. This study used the Human Relations Area Files for information on the diets of Amerindian groups in the Amazon Basin from 1950 to the present, and used other published sources and the authors' own data. Data on food use was identified for only nine groups and dietary intake data for individuals in only three of the groups. A diet based on starchy staples (manioc and plantains) and fish, supplemented with a limited variety of other plant and animal foods, was found. Bitter manioc-based foods were associated with the consumption of cyanogens and fish with the consumption of mercury. Diets of adults appear to be adequate in energy and protein and low in fats. Children's diets were not well documented. Based on the limited available data, Amazonian diets are restricted in variety, but appear to be adequate in energy and protein for adults, but likely insufficiently nutrient-dense for children.
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Spatial patterns and fire response of recent Amazonian droughts
NASA Astrophysics Data System (ADS)
Aragão, Luiz Eduardo O. C.; Malhi, Yadvinder; Roman-Cuesta, Rosa Maria; Saatchi, Sassan; Anderson, Liana O.; Shimabukuro, Yosio Edemir
2007-04-01
There has been an increasing awareness of the possibility of climate change causing increased drought frequency in Amazonia, with ensuing impacts on ecosystems and human populations. This debate has been brought into focus by the 1997/1998 and 2005 Amazonian droughts. We analysed the spatial extent of these droughts and fire response to the 2005 drought with TRMM and NOAA-12 data, respectively. Both droughts had distinct fingerprints. The 2005 drought was characterized by its intensification throughout the dry season in south-western Amazonia. During 2005 the annual cumulative number of hot pixels in Amazonia increased 33% in relation to the 1999-2005 mean. In the Brazilian state of Acre, at the epicentre of the 2005 drought, the area of leakage forest fires was more than five times greater than the area directly deforested. Fire leakage into flammable forests may be the major agent of biome transformation in the event of increasing drought frequency.
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Torralvo, Kelly; Rabelo, Rafael M; Andrade, Alfredo; Botero-Arias, Robinson
2017-04-01
Descriptions of new tool-use events are important for understanding how ecological context may drive the evolution of tool use among primate traditions. Here, we report a possible case of the first record of tool use by wild Amazonian capuchin monkeys (Sapajus macrocephalus). The record was made by a camera trap, while we were monitoring caiman nest predation at Mamirauá Reserve in Central Amazonia. An adult individual was registered in a bipedal posture, apparently using a branch as a shovel to dig eggs out of a nest. Caiman eggs are frequently depredated by opportunistic animals, such as the capuchin monkeys. As the Mamirauá Reserve is covered by a high-productivity forest, and caiman eggs are a high-quality food resource seasonally available on the ground, we believe that tool use by capuchins is more likely to be opportunity driven, rather than necessity driven, in our study site.
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Luke L. Powell; Jared D. Wolfe; Erik I. Johnson; James E. Hines; James D. Nichols; Philip C Stouffer
2015-01-01
Given rates of deforestation, disturbance, and secondary forest accumulation in tropical rainforests, there is a great need to quantify habitat use and movement among different habitats. This need is particularly pronounced for animals most sensitive to disturbance, such as insectivorous understory birds. Here we use multistate captureârecapture models with...
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Levis, Carolina; de Souza, Priscila Figueira; Schietti, Juliana; Emilio, Thaise; Pinto, José Luiz Purri da Veiga; Clement, Charles R.; Costa, Flavia R. C.
2012-01-01
Background Native Amazonian populations managed forest resources in numerous ways, often creating oligarchic forests dominated by useful trees. The scale and spatial distribution of forest modification beyond pre-Columbian settlements is still unknown, although recent studies propose that human impact away from rivers was minimal. We tested the hypothesis that past human management of the useful tree community decreases with distance from rivers. Methodology/Principal Findings In six sites, we inventoried trees and palms with DBH≥10 cm and collected soil for charcoal analysis; we also mapped archaeological evidence around the sites. To quantify forest manipulation, we measured the relative abundance, richness and basal area of useful trees and palms. We found a strong negative exponential relationship between forest manipulation and distance to large rivers. Plots located from 10 to 20 km from a main river had 20–40% useful arboreal species, plots between 20 and 40 km had 12–23%, plots more than 40 km had less than 15%. Soil charcoal abundance was high in the two sites closest to secondary rivers, suggesting past agricultural practices. The shortest distance between archaeological evidence and plots was found in sites near rivers. Conclusions/Significance These results strongly suggest that past forest manipulation was not limited to the pre-Columbian settlements along major rivers, but extended over interfluvial areas considered to be primary forest today. The sustainable use of Amazonian forests will be most effective if it considers the degree of past landscape domestication, as human-modified landscapes concentrate useful plants for human sustainable use and management today. PMID:23185264
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Late Quaternary landscape evolution of northeastern Amazonia from pollen and diatom records.
Castro, Darciléa F; De Oliveira, Paulo E; Rossetti, Dilce F; Pessenda, Luiz C R
2013-03-01
The main goal of this study was to reconstruct the Late Pleistocene-Holocene floristic composition in an area of the northern Brazilian Amazonia, comparing the results with other Amazonian localities in order to discuss the factors that have influenced phytophysiognomic changes over this time period. The work in eastern Marajó Island at the mouth of the Amazonas River was approached based on analysis of 98 pollen and diatom samples from core data distributed along a proximal to distal transect of a paleoestuarine system. The results indicated high concentration of Rhizophora, associated with arboreal pollen grains typical of the modern Amazonian rainforest during the last 40,000 cal yrs BP. Pollen composition also included wetland herbs. Diatoms were dominated by marine and fresh water taxa. Wetland forest, mangrove and, subordinately herbs remained constant during most of the latest Pleistocene-early/middle Holocene. At 5,000 cal yrs BP, there was a distinguished change from forest and mangrove to wet grassland savanna due to sea level fluctuation. As marine influence decreased, the estuary gave rise to fresh water lacustrine and swamp environments, with establishment of herbaceous campos. A main conclusion from this study is that solely the occurrence of herbaceous savanna can not be used as a definitive indicator of past dry climates in Amazonian areas.
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Hunting in the Rainforest and Mayaro Virus Infection: An emerging Alphavirus in Ecuador.
Izurieta, Ricardo O; Macaluso, Maurizio; Watts, Douglas M; Tesh, Robert B; Guerra, Bolivar; Cruz, Ligia M; Galwankar, Sagar; Vermund, Sten H
2011-10-01
The objectives of this report were to document the potential presence of Mayaro virus infection in Ecuador and to examine potential risk factors for Mayaro virus infection among the personnel of a military garrison in the Amazonian rainforest. The study population consisted of the personnel of a garrison located in the Ecuadorian Amazonian rainforest. The cross-sectional study employed interviews and seroepidemiological methods. Humoral immune response to Mayaro virus infection was assessed by evaluating IgM- and IgG-specific antibodies using ELISA. Of 338 subjects studied, 174 were from the Coastal zone of Ecuador, 73 from Andean zone, and 91 were native to the Amazonian rainforest. Seroprevalence of Mayaro virus infection was more than 20 times higher among Amazonian natives (46%) than among subjects born in other areas (2%). Age and hunting in the rainforest were significant predictors of Mayaro virus infection overall and among Amazonian natives. The results provide the first demonstration of the potential presence of Mayaro virus infection in Ecuador and a systematic evaluation of risk factors for the transmission of this alphavirus. The large difference in prevalence rates between Amazonian natives and other groups and between older and younger natives suggest that Mayaro virus is endemic and enzootic in the rainforest, with sporadic outbreaks that determine differences in risk between birth cohorts of natives. Deep forest hunting may selectively expose native men, descendants of the Shuar and Huaronai ethnic groups, to the arthropod vectors of Mayaro virus in areas close to primate reservoirs.
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Resilient networks of ant-plant mutualists in Amazonian forest fragments.
Passmore, Heather A; Bruna, Emilio M; Heredia, Sylvia M; Vasconcelos, Heraldo L
2012-01-01
The organization of networks of interacting species, such as plants and animals engaged in mutualisms, strongly influences the ecology and evolution of partner communities. Habitat fragmentation is a globally pervasive form of spatial heterogeneity that could profoundly impact the structure of mutualist networks. This is particularly true for biodiversity-rich tropical ecosystems, where the majority of plant species depend on mutualisms with animals and it is thought that changes in the structure of mutualist networks could lead to cascades of extinctions. We evaluated effects of fragmentation on mutualistic networks by calculating metrics of network structure for ant-plant networks in continuous Amazonian forests with those in forest fragments. We hypothesized that networks in fragments would have fewer species and higher connectance, but equal nestedness and resilience compared to forest networks. Only one of the nine metrics we compared differed between continuous forest and forest fragments, indicating that networks were resistant to the biotic and abiotic changes that accompany fragmentation. This is partially the result of the loss of only specialist species with one connection that were lost in forest fragments. We found that the networks of ant-plant mutualists in twenty-five year old fragments are similar to those in continuous forest, suggesting these interactions are resistant to the detrimental changes associated with habitat fragmentation, at least in landscapes that are a mosaic of fragments, regenerating forests, and pastures. However, ant-plant mutualistic networks may have several properties that may promote their persistence in fragmented landscapes. Proactive identification of key mutualist partners may be necessary to focus conservation efforts on the interactions that insure the integrity of network structure and the ecosystems services networks provide.
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The linkages between photosynthesis, productivity, growth and biomass in lowland Amazonian forests.
Malhi, Yadvinder; Doughty, Christopher E; Goldsmith, Gregory R; Metcalfe, Daniel B; Girardin, Cécile A J; Marthews, Toby R; Del Aguila-Pasquel, Jhon; Aragão, Luiz E O C; Araujo-Murakami, Alejandro; Brando, Paulo; da Costa, Antonio C L; Silva-Espejo, Javier E; Farfán Amézquita, Filio; Galbraith, David R; Quesada, Carlos A; Rocha, Wanderley; Salinas-Revilla, Norma; Silvério, Divino; Meir, Patrick; Phillips, Oliver L
2015-06-01
Understanding the relationship between photosynthesis, net primary productivity and growth in forest ecosystems is key to understanding how these ecosystems will respond to global anthropogenic change, yet the linkages among these components are rarely explored in detail. We provide the first comprehensive description of the productivity, respiration and carbon allocation of contrasting lowland Amazonian forests spanning gradients in seasonal water deficit and soil fertility. Using the largest data set assembled to date, ten sites in three countries all studied with a standardized methodology, we find that (i) gross primary productivity (GPP) has a simple relationship with seasonal water deficit, but that (ii) site-to-site variations in GPP have little power in explaining site-to-site spatial variations in net primary productivity (NPP) or growth because of concomitant changes in carbon use efficiency (CUE), and conversely, the woody growth rate of a tropical forest is a very poor proxy for its productivity. Moreover, (iii) spatial patterns of biomass are much more driven by patterns of residence times (i.e. tree mortality rates) than by spatial variation in productivity or tree growth. Current theory and models of tropical forest carbon cycling under projected scenarios of global atmospheric change can benefit from advancing beyond a focus on GPP. By improving our understanding of poorly understood processes such as CUE, NPP allocation and biomass turnover times, we can provide more complete and mechanistic approaches to linking climate and tropical forest carbon cycling. © 2015 John Wiley & Sons Ltd.
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Dick, Christopher W; Etchelecu, Gabriela; Austerlitz, Frédéric
2003-03-01
Tropical rainforest trees typically occur in low population densities and rely on animals for cross-pollination. It is of conservation interest therefore to understand how rainforest fragmentation may alter the pollination and breeding structure of remnant trees. Previous studies of the Amazonian tree Dinizia excelsa (Fabaceae) found African honeybees (Apis mellifera scutellata) as the predominant pollinators of trees in highly disturbed habitats, transporting pollen up to 3.2 km between pasture trees. Here, using microsatellite genotypes of seed arrays, we compare outcrossing rates and pollen dispersal distances of (i) remnant D. excelsa in three large ranches, and (ii) a population in undisturbed forest in which African honeybees were absent. Self-fertilization was more frequent in the disturbed habitats (14%, n = 277 seeds from 12 mothers) than in undisturbed forest (10%, n = 295 seeds from 13 mothers). Pollen dispersal was extensive in all three ranches compared to undisturbed forest, however. Using a twogener analysis, we estimated a mean pollen dispersal distance of 1509 m in Colosso ranch, assuming an exponential dispersal function, and 212 m in undisturbed forest. The low effective density of D. excelsa in undisturbed forest (approximately 0.1 trees/ha) indicates that large areas of rainforest must be preserved to maintain minimum viable populations. Our results also suggest, however, that in highly disturbed habitats Apis mellifera may expand genetic neighbourhood areas, thereby linking fragmented and continuous forest populations.
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A New Infrared Desert Dust Index over French Guyana Rain forest: First results
NASA Astrophysics Data System (ADS)
Molinie, J.; Barnacin, E.; Henry, J. L.; Gobinddass, M. L.; Panechou-Pulcherie, K.; Feuillard, T.; Nagau, J.
2017-12-01
Recently a NASA researcher showed the role of desert dust contribution for the Amazonian rain forest. In another hand, desert dust impact population health when PM 10 level reached values around and upper the PM 10 threshold of the 50 µg m-3, established by the World Health Organization (WHO). Infrared Desert Dust Index (IDDI) developed by Legrand with Meteosat infrared images, allow the following of desert dust plumes over semi-arid land. In French Guiana the WHO threshold is currently overpass in measurements done by ORA air quality network, in the two main towns located close to the coast. For inland population, it is very difficult to have continuous dust measures due to the low infrastructure supplies. We need to develop a tools in order to follow the crossing of desert dust over the French Guyana rain forest, from the coast to inland villages. Following the IDDI concept and comparing with VIIRS AOT EDR result over the same area, a modified IDDI for Amazonian region (IDDI_A) has been proposed to identify the dusty pixels over the forest. Despite of high cloud presence, a good correlation between AOT EDR and IDDI_A was obtained. The IDDI_A calculation has been applied over French Guiana area for different PM 10 level at Cayenne, a town along the coast.
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Lessons from a Community-Based Program to Monitor Forest Vertebrates in the Brazilian Amazon
NASA Astrophysics Data System (ADS)
Benchimol, Maíra; von Mühlen, Eduardo M.; Venticinque, Eduardo M.
2017-09-01
A large number of sustainable use reserves recently have been titled in the Brazilian Amazonia. These reserves require public participation in the design and implementation of management and monitoring programs. Species-monitoring programs that engage local stakeholders may be useful for assessing wildlife status over the long term. We collaborated on the development of a participatory program to monitor forest vertebrates in the Piagaçu-Purus Sustainable Development Reserve and to build capacity among the local people. We examined relations between the distance to the nearest human community and sighting rates of each species, and evaluated the program overall. Eighteen wildlife monitors received training in line transect and sign surveys and then conducted surveys along a total of ten transects. Sighting rates of most species in the Piagaçu-Purus Sustainable Development Reserve were higher than those reported in other Amazonian forests. Distance to the human community was not associated with the overall vertebrate sighting rate. Use of the trained monitors was successful in terms of data acquisition and engagement. The involvement of local people promoted discussions about regulation of hunting in the reserve. Implementation of community-based programs to monitor forest wildlife in Amazonian sustainable use reserves may empower local communities and assess the status of wildlife through time.
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Exploring the likelihood and mechanism of a climate-change-induced dieback of the Amazon rainforest
Malhi, Yadvinder; Aragão, Luiz E. O. C.; Galbraith, David; Huntingford, Chris; Fisher, Rosie; Zelazowski, Przemyslaw; Sitch, Stephen; McSweeney, Carol; Meir, Patrick
2009-01-01
We examine the evidence for the possibility that 21st-century climate change may cause a large-scale “dieback” or degradation of Amazonian rainforest. We employ a new framework for evaluating the rainfall regime of tropical forests and from this deduce precipitation-based boundaries for current forest viability. We then examine climate simulations by 19 global climate models (GCMs) in this context and find that most tend to underestimate current rainfall. GCMs also vary greatly in their projections of future climate change in Amazonia. We attempt to take into account the differences between GCM-simulated and observed rainfall regimes in the 20th century. Our analysis suggests that dry-season water stress is likely to increase in E. Amazonia over the 21st century, but the region tends toward a climate more appropriate to seasonal forest than to savanna. These seasonal forests may be resilient to seasonal drought but are likely to face intensified water stress caused by higher temperatures and to be vulnerable to fires, which are at present naturally rare in much of Amazonia. The spread of fire ignition associated with advancing deforestation, logging, and fragmentation may act as nucleation points that trigger the transition of these seasonal forests into fire-dominated, low biomass forests. Conversely, deliberate limitation of deforestation and fire may be an effective intervention to maintain Amazonian forest resilience in the face of imposed 21st-century climate change. Such intervention may be enough to navigate E. Amazonia away from a possible “tipping point,” beyond which extensive rainforest would become unsustainable. PMID:19218454
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Exploring the likelihood and mechanism of a climate-change-induced dieback of the Amazon rainforest.
Malhi, Yadvinder; Aragão, Luiz E O C; Galbraith, David; Huntingford, Chris; Fisher, Rosie; Zelazowski, Przemyslaw; Sitch, Stephen; McSweeney, Carol; Meir, Patrick
2009-12-08
We examine the evidence for the possibility that 21st-century climate change may cause a large-scale "dieback" or degradation of Amazonian rainforest. We employ a new framework for evaluating the rainfall regime of tropical forests and from this deduce precipitation-based boundaries for current forest viability. We then examine climate simulations by 19 global climate models (GCMs) in this context and find that most tend to underestimate current rainfall. GCMs also vary greatly in their projections of future climate change in Amazonia. We attempt to take into account the differences between GCM-simulated and observed rainfall regimes in the 20th century. Our analysis suggests that dry-season water stress is likely to increase in E. Amazonia over the 21st century, but the region tends toward a climate more appropriate to seasonal forest than to savanna. These seasonal forests may be resilient to seasonal drought but are likely to face intensified water stress caused by higher temperatures and to be vulnerable to fires, which are at present naturally rare in much of Amazonia. The spread of fire ignition associated with advancing deforestation, logging, and fragmentation may act as nucleation points that trigger the transition of these seasonal forests into fire-dominated, low biomass forests. Conversely, deliberate limitation of deforestation and fire may be an effective intervention to maintain Amazonian forest resilience in the face of imposed 21st-century climate change. Such intervention may be enough to navigate E. Amazonia away from a possible "tipping point," beyond which extensive rainforest would become unsustainable.
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Fire-free land use in pre-1492 Amazonian savannas
Iriarte, José; Power, Mitchell J.; Rostain, Stéphen; Mayle, Francis E.; Jones, Huw; Watling, Jennifer; Whitney, Bronwen S.; McKey, Doyle B.
2012-01-01
The nature and scale of pre-Columbian land use and the consequences of the 1492 “Columbian Encounter” (CE) on Amazonia are among the more debated topics in New World archaeology and paleoecology. However, pre-Columbian human impact in Amazonian savannas remains poorly understood. Most paleoecological studies have been conducted in neotropical forest contexts. Of studies done in Amazonian savannas, none has the temporal resolution needed to detect changes induced by either climate or humans before and after A.D. 1492, and only a few closely integrate paleoecological and archaeological data. We report a high-resolution 2,150-y paleoecological record from a French Guianan coastal savanna that forces reconsideration of how pre-Columbian savanna peoples practiced raised-field agriculture and how the CE impacted these societies and environments. Our combined pollen, phytolith, and charcoal analyses reveal unexpectedly low levels of biomass burning associated with pre-A.D. 1492 savanna raised-field agriculture and a sharp increase in fires following the arrival of Europeans. We show that pre-Columbian raised-field farmers limited burning to improve agricultural production, contrasting with extensive use of fire in pre-Columbian tropical forest and Central American savanna environments, as well as in present-day savannas. The charcoal record indicates that extensive fires in the seasonally flooded savannas of French Guiana are a post-Columbian phenomenon, postdating the collapse of indigenous populations. The discovery that pre-Columbian farmers practiced fire-free savanna management calls into question the widely held assumption that pre-Columbian Amazonian farmers pervasively used fire to manage and alter ecosystems and offers fresh perspectives on an emerging alternative approach to savanna land use and conservation that can help reduce carbon emissions. PMID:22493248
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Dorea, Jose G
2003-07-01
The Amazon rain forest extends over an area of 7.8x10(6)km(2) in nine countries. It harbors a diverse human population distributed in dense cities and isolated communities with extreme levels of infrastructure. Amazonian forest people, either autochthons or frontier riparians (ribeirinhos) living in isolated areas, share the same environment for survival and nutritional status. The peculiarities of the hydrological cycle determine disease patterns, agricultural conditions, and food availability. Feeding strategies depend heavily on cassava products and fish. These two foods carry toxic substances such as linamarin (naturally present in cassava) and monomethyl mercury (MMHg) (bioconcentrated in fish flesh) that cause neurotoxic diseases in other parts of the world but not in Amazonia, where neurotoxic cases of food origin are rare and not related to these staples. While cassava detoxification processes may partly explain its safe consumption, the Hg concentrations in Amazonian fish are within traditionally safe limits for this population and contribute to an important metabolic interaction with cassava. The gold rush of the 1970s and 1980s brought large-scale environmental disruption and physical destruction of ecosystems at impact points, along with a heavy discharge of metallic Hg. The discharged Hg has not yet impacted on MMHg concentrations in fish or in hair of fish consumers. Hair Hg concentration, used as a biomarker of fish consumption, indicates that the Amazonian riparians are acquiring an excellent source of protein carrying important nutrients, the lack of which could aggravate their existing health problems. Therefore, in a scenario of insufficient health services and an unhealthy environment, food habits based on fish consumption are part of a successful survival strategy and recommendations for changes are not yet justifiable.
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Abrupt Increases in Amazonian Tree Mortality Due to Drought-Fire Interactions
NASA Technical Reports Server (NTRS)
Brando, Paulo Monteiro; Balch, Jennifer K.; Nepstad, Daniel C.; Morton, Douglas C.; Putz, Francis E.; Coe, Michael T.; Silverio, Divino; Macedo, Marcia N.; Davidson, Eric A.; Nobrega, Caroline C.;
2014-01-01
Interactions between climate and land-use change may drive widespread degradation of Amazonian forests. High-intensity fires associated with extreme weather events could accelerate this degradation by abruptly increasing tree mortality, but this process remains poorly understood. Here we present, to our knowledge, the first field-based evidence of a tipping point in Amazon forests due to altered fire regimes. Based on results of a large-scale, longterm experiment with annual and triennial burn regimes (B1yr and B3yr, respectively) in the Amazon, we found abrupt increases in fire-induced tree mortality (226 and 462%) during a severe drought event, when fuel loads and air temperatures were substantially higher and relative humidity was lower than long-term averages. This threshold mortality response had a cascading effect, causing sharp declines in canopy cover (23 and 31%) and aboveground live biomass (12 and 30%) and favoring widespread invasion by flammable grasses across the forest edge area (80 and 63%), where fires were most intense (e.g., 220 and 820 kW x m(exp -1)). During the droughts of 2007 and 2010, regional forest fires burned 12 and 5% of southeastern Amazon forests, respectively, compared with less than 1% in nondrought years. These results show that a few extreme drought events, coupled with forest fragmentation and anthropogenic ignition sources, are already causing widespread fire-induced tree mortality and forest degradation across southeastern Amazon forests. Future projections of vegetation responses to climate change across drier portions of the Amazon require more than simulation of global climate forcing alone and must also include interactions of extreme weather events, fire, and land-use change.
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Abrupt increases in Amazonian tree mortality due to drought-fire interactions.
Brando, Paulo Monteiro; Balch, Jennifer K; Nepstad, Daniel C; Morton, Douglas C; Putz, Francis E; Coe, Michael T; Silvério, Divino; Macedo, Marcia N; Davidson, Eric A; Nóbrega, Caroline C; Alencar, Ane; Soares-Filho, Britaldo S
2014-04-29
Interactions between climate and land-use change may drive widespread degradation of Amazonian forests. High-intensity fires associated with extreme weather events could accelerate this degradation by abruptly increasing tree mortality, but this process remains poorly understood. Here we present, to our knowledge, the first field-based evidence of a tipping point in Amazon forests due to altered fire regimes. Based on results of a large-scale, long-term experiment with annual and triennial burn regimes (B1yr and B3yr, respectively) in the Amazon, we found abrupt increases in fire-induced tree mortality (226 and 462%) during a severe drought event, when fuel loads and air temperatures were substantially higher and relative humidity was lower than long-term averages. This threshold mortality response had a cascading effect, causing sharp declines in canopy cover (23 and 31%) and aboveground live biomass (12 and 30%) and favoring widespread invasion by flammable grasses across the forest edge area (80 and 63%), where fires were most intense (e.g., 220 and 820 kW ⋅ m(-1)). During the droughts of 2007 and 2010, regional forest fires burned 12 and 5% of southeastern Amazon forests, respectively, compared with <1% in nondrought years. These results show that a few extreme drought events, coupled with forest fragmentation and anthropogenic ignition sources, are already causing widespread fire-induced tree mortality and forest degradation across southeastern Amazon forests. Future projections of vegetation responses to climate change across drier portions of the Amazon require more than simulation of global climate forcing alone and must also include interactions of extreme weather events, fire, and land-use change.
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Abrupt increases in Amazonian tree mortality due to drought–fire interactions
Brando, Paulo Monteiro; Balch, Jennifer K.; Nepstad, Daniel C.; Morton, Douglas C.; Putz, Francis E.; Coe, Michael T.; Silvério, Divino; Macedo, Marcia N.; Davidson, Eric A.; Nóbrega, Caroline C.; Alencar, Ane; Soares-Filho, Britaldo S.
2014-01-01
Interactions between climate and land-use change may drive widespread degradation of Amazonian forests. High-intensity fires associated with extreme weather events could accelerate this degradation by abruptly increasing tree mortality, but this process remains poorly understood. Here we present, to our knowledge, the first field-based evidence of a tipping point in Amazon forests due to altered fire regimes. Based on results of a large-scale, long-term experiment with annual and triennial burn regimes (B1yr and B3yr, respectively) in the Amazon, we found abrupt increases in fire-induced tree mortality (226 and 462%) during a severe drought event, when fuel loads and air temperatures were substantially higher and relative humidity was lower than long-term averages. This threshold mortality response had a cascading effect, causing sharp declines in canopy cover (23 and 31%) and aboveground live biomass (12 and 30%) and favoring widespread invasion by flammable grasses across the forest edge area (80 and 63%), where fires were most intense (e.g., 220 and 820 kW⋅m−1). During the droughts of 2007 and 2010, regional forest fires burned 12 and 5% of southeastern Amazon forests, respectively, compared with <1% in nondrought years. These results show that a few extreme drought events, coupled with forest fragmentation and anthropogenic ignition sources, are already causing widespread fire-induced tree mortality and forest degradation across southeastern Amazon forests. Future projections of vegetation responses to climate change across drier portions of the Amazon require more than simulation of global climate forcing alone and must also include interactions of extreme weather events, fire, and land-use change. PMID:24733937
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Thresholds of species loss in Amazonian deforestation frontier landscapes.
Ochoa-Quintero, Jose Manuel; Gardner, Toby A; Rosa, Isabel; Ferraz, Silvio Frosini de Barros; Sutherland, William J
2015-04-01
In the Brazilian Amazon, private land accounts for the majority of remaining native vegetation. Understanding how land-use change affects the composition and distribution of biodiversity in farmlands is critical for improving conservation strategies in the face of rapid agricultural expansion. Working across an area exceeding 3 million ha in the southwestern state of Rondônia, we assessed how the extent and configuration of remnant forest in replicate 10,000-ha landscapes has affected the occurrence of a suite of Amazonian mammals and birds. In each of 31 landscapes, we used field sampling and semistructured interviews with landowners to determine the presence of 28 large and medium sized mammals and birds, as well as a further 7 understory birds. We then combined results of field surveys and interviews with a probabilistic model of deforestation. We found strong evidence for a threshold response of sampled biodiversity to landscape level forest cover; landscapes with <30-40% forest cover hosted markedly fewer species. Results from field surveys and interviews yielded similar thresholds. These results imply that in partially deforested landscapes many species are susceptible to extirpation following relatively small additional reductions in forest area. In the model of deforestation by 2030 the number of 10,000-ha landscapes under a conservative threshold of 43% forest cover almost doubled, such that only 22% of landscapes would likely to be able to sustain at least 75% of the 35 focal species we sampled. Brazilian law requires rural property owners in the Amazon to retain 80% forest cover, although this is rarely achieved. Prioritizing efforts to ensure that entire landscapes, rather than individual farms, retain at least 50% forest cover may help safeguard native biodiversity in private forest reserves in the Amazon. © 2015 Society for Conservation Biology.
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Drought sensitivity of Amazonian carbon balance revealed by atmospheric measurements.
Gatti, L V; Gloor, M; Miller, J B; Doughty, C E; Malhi, Y; Domingues, L G; Basso, L S; Martinewski, A; Correia, C S C; Borges, V F; Freitas, S; Braz, R; Anderson, L O; Rocha, H; Grace, J; Phillips, O L; Lloyd, J
2014-02-06
Feedbacks between land carbon pools and climate provide one of the largest sources of uncertainty in our predictions of global climate. Estimates of the sensitivity of the terrestrial carbon budget to climate anomalies in the tropics and the identification of the mechanisms responsible for feedback effects remain uncertain. The Amazon basin stores a vast amount of carbon, and has experienced increasingly higher temperatures and more frequent floods and droughts over the past two decades. Here we report seasonal and annual carbon balances across the Amazon basin, based on carbon dioxide and carbon monoxide measurements for the anomalously dry and wet years 2010 and 2011, respectively. We find that the Amazon basin lost 0.48 ± 0.18 petagrams of carbon per year (Pg C yr(-1)) during the dry year but was carbon neutral (0.06 ± 0.1 Pg C yr(-1)) during the wet year. Taking into account carbon losses from fire by using carbon monoxide measurements, we derived the basin net biome exchange (that is, the carbon flux between the non-burned forest and the atmosphere) revealing that during the dry year, vegetation was carbon neutral. During the wet year, vegetation was a net carbon sink of 0.25 ± 0.14 Pg C yr(-1), which is roughly consistent with the mean long-term intact-forest biomass sink of 0.39 ± 0.10 Pg C yr(-1) previously estimated from forest censuses. Observations from Amazonian forest plots suggest the suppression of photosynthesis during drought as the primary cause for the 2010 sink neutralization. Overall, our results suggest that moisture has an important role in determining the Amazonian carbon balance. If the recent trend of increasing precipitation extremes persists, the Amazon may become an increasing carbon source as a result of both emissions from fires and the suppression of net biome exchange by drought.
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NASA Astrophysics Data System (ADS)
Zhang, K.; Castanho, A. D.; Moghim, S.; Bras, R. L.; Coe, M. T.; Costa, M. H.; Levine, N. M.; Longo, M.; McKnight, S.; Wang, J.; Moorcroft, P. R.
2012-12-01
Deforestation and drought have imposed regional-scale perturbations onto Amazonian ecosystems and are predicted to cause larger negative impacts on the Amazonian ecosystems and associated regional carbon dynamics in the 21st century. However, global climate models (GCMs) vary greatly in their projections of future climate change in Amazonia, giving rise to uncertainty in the expected fate of the Amazon over the coming century. In this study, we explore the possible eco-hydrological consequences of the Amazonian ecosystems under projected climate and land-use changes in the 21st century using two state-of-the-art terrestrial ecosystem models—Ecosystem Demography Model 2.1(ED2.1) and Integrated Biosphere Simulator model (IBIS)—driven by three representative, bias-corrected climate projections from three IPCC GCMs (NCARPCM1, NCARCCSM3 and HadCM3), coupled with two land-use change scenarios (a business-as-usual and a strict governance scenario). We also analyze the relative roles of climate change, CO2 fertilization, land-use change and fire in driving the projected composition and structure of the Amazonian ecosystems. Our results show that CO2 fertilization enhances vegetation productivity and above-ground biomass (AGB) in the region, while land-use change and fire cause AGB loss and the replacement of forests by the savanna-like vegetation. The impacts of climate change depend strongly on the direction and severity of projected precipitation changes in the region. In particular, when intensified water stress is superimposed on unregulated deforestation, both ecosystem models predict large-scale dieback of Amazonian rainforests.
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Hunting in the Rainforest and Mayaro Virus Infection: An emerging Alphavirus in Ecuador
Izurieta, Ricardo O; Macaluso, Maurizio; Watts, Douglas M; Tesh, Robert B; Guerra, Bolivar; Cruz, Ligia M; Galwankar, Sagar; Vermund, Sten H
2011-01-01
Objectives: The objectives of this report were to document the potential presence of Mayaro virus infection in Ecuador and to examine potential risk factors for Mayaro virus infection among the personnel of a military garrison in the Amazonian rainforest. Materials and Methods: The study population consisted of the personnel of a garrison located in the Ecuadorian Amazonian rainforest. The cross-sectional study employed interviews and seroepidemiological methods. Humoral immune response to Mayaro virus infection was assessed by evaluating IgM- and IgG-specific antibodies using ELISA. Results: Of 338 subjects studied, 174 were from the Coastal zone of Ecuador, 73 from Andean zone, and 91 were native to the Amazonian rainforest. Seroprevalence of Mayaro virus infection was more than 20 times higher among Amazonian natives (46%) than among subjects born in other areas (2%). Conclusions: Age and hunting in the rainforest were significant predictors of Mayaro virus infection overall and among Amazonian natives. The results provide the first demonstration of the potential presence of Mayaro virus infection in Ecuador and a systematic evaluation of risk factors for the transmission of this alphavirus. The large difference in prevalence rates between Amazonian natives and other groups and between older and younger natives suggest that Mayaro virus is endemic and enzootic in the rainforest, with sporadic outbreaks that determine differences in risk between birth cohorts of natives. Deep forest hunting may selectively expose native men, descendants of the Shuar and Huaronai ethnic groups, to the arthropod vectors of Mayaro virus in areas close to primate reservoirs. PMID:22223990
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Worldwide Emerging Environmental Issues Affecting the U.S. Military
2010-08-01
Brazil protecting non-Amazonian tropical forests . A summary of the consultations across the region are presented in the UNDP LAC Regional...North-American Environmental Integration……..13 6.6 World’s Humid Tropical Forests to Suffer Considerable Biodiversity Change by 2100….…13 6.7 Latin...35456&Cr=sanitation&Cr1 Item 2. Food Security Concerns Increase Around the World The Food Security Risk Index 2010 reveals that the countries most
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Reduction of Genetic Diversity of the Harpy Eagle in Brazilian Tropical Forests.
Banhos, Aureo; Hrbek, Tomas; Sanaiotti, Tânia M; Farias, Izeni Pires
2016-01-01
Habitat loss and fragmentation intensify the effects of genetic drift and endogamy, reducing genetic variability of populations with serious consequences for wildlife conservation. The Harpy Eagle (Harpia harpyja) is a forest dwelling species that is considered near threatened and suffers from habitat loss in the forests of the Neotropical region. In this study, 72 historical and current samples were assessed using eight autosomal microsatellite markers to investigate the distribution of genetic diversity of the Harpy Eagle of the Amazonian and Atlantic forests in Brazil. The results showed that the genetic diversity of Harpy Eagle decreased in the regions where deforestation is intense in the southern Amazon and Atlantic Forest.
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Reduction of Genetic Diversity of the Harpy Eagle in Brazilian Tropical Forests
2016-01-01
Habitat loss and fragmentation intensify the effects of genetic drift and endogamy, reducing genetic variability of populations with serious consequences for wildlife conservation. The Harpy Eagle (Harpia harpyja) is a forest dwelling species that is considered near threatened and suffers from habitat loss in the forests of the Neotropical region. In this study, 72 historical and current samples were assessed using eight autosomal microsatellite markers to investigate the distribution of genetic diversity of the Harpy Eagle of the Amazonian and Atlantic forests in Brazil. The results showed that the genetic diversity of Harpy Eagle decreased in the regions where deforestation is intense in the southern Amazon and Atlantic Forest. PMID:26871719
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Multi-scale assessment of human-induced changes to Amazonian instream habitats
Context: Land use change and forest degradation have myriad effects on tropical ecosystems. Yet their consequences for low-order streams remain very poorly understood, including in the world´s largest freshwater basin, the Amazon.Objectives: Determine the degree to which ph...
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Impacts of hydroelectric dams on alluvial riparian plant communities in Eastern Brazilian Amazonian.
Ferreira, Leandro Valle; Cunha, Denise A; Chaves, Priscilla P; Matos, Darley C L; Parolin, Pia
2013-09-01
The major rivers of the Amazon River basin and their biota are threatened by the planned construction of large hydroelectric dams that are expected to have strong impacts on floodplain plant communities. The present study presents forest inventories from three floodplain sites colonized by alluvial riparian vegetation in the Tapajós, Xingu and Tocantins River basins in eastern Amazonian. Results indicate that tree species of the highly specialized alluvial riparian vegetation are clearly distinct among the three river basins, although they are not very distinct from each other and environmental constraints are very similar. With only 6 of 74 species occurring in all three inventories, most tree and shrub species are restricted to only one of the rivers, indicating a high degree of local distribution. Different species occupy similar environmental niches, making these fragile riparian formations highly valuable. Conservation plans must consider species complementarily when decisions are made on where to place floodplain forest conservation units to avoid the irreversible loss of unique alluvial riparian vegetation biodiversity.
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NASA Astrophysics Data System (ADS)
Lambs, Luc; Muller, Etienne; Fromard, F.
2007-08-01
SummaryFrench Guiana is notable for the extent of its rain forests, which occupy 97% of the country, and the influence of the Amazon along its shores. In fact, the shores and estuaries support a mangrove forest typical of saline conditions. This paper reports the chemical characteristics, conductivity and salinity and the stable isotopes (oxygen and deuterium) of the rivers and shores between the Cayenne area and the border with Surinam. The results show a quite homogenous freshwater pool over the country. However, the low slope of the coast, a result of the wide mud banks deposited by the Amazonian plume, have turned the mouths of the smaller rivers to the northwest, creating large salty areas where mangroves grow several kilometers inland. Despite the large amount of Amazonian water, the Guianan coast exhibits high salinity. In fact, the freshwater itself remains far from the shore, following the north Brazilian current, while only the mud plume arrives at the coast, creating this paradox.
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Unexpected high diversity of galling insects in the Amazonian upper canopy: the savanna out there.
Julião, Genimar R; Venticinque, Eduardo M; Fernandes, G Wilson; Price, Peter W
2014-01-01
A relatively large number of studies reassert the strong relationship between galling insect diversity and extreme hydric and thermal status in some habitats, and an overall pattern of a greater number of galling species in the understory of scleromorphic vegetation. We compared galling insect diversity in the forest canopy and its relationship with tree richness among upland terra firme, várzea, and igapó floodplains in Amazonia, Brazil. The soils of these forest types have highly different hydric and nutritional status. Overall, we examined the upper layer of 1,091 tree crowns. Galling species richness and abundance were higher in terra firme forests compared to várzea and igapó forests. GLM-ANCOVA models revealed that the number of tree species sampled in each forest type was determinant in the gall-forming insect diversity. The ratio between galling insect richness and number of tree species sampled (GIR/TSS ratio) was higher in the terra firme forest and in seasonally flooded igapó, while the várzea presented the lowest GIR/TSS ratio. In this study, we recorded unprecedented values of galling species diversity and abundance per sampling point. The GIR/TSS ratio from várzea was approximately 2.5 times higher than the highest value of this ratio ever reported in the literature. Based on this fact, we ascertained that várzea and igapó floodplain forests (with lower GIA and GIR), together with the speciose terra firme galling community emerge as the gall diversity apex landscape among all biogeographic regions already investigated. Contrary to expectation, our results also support the "harsh environment hypothesis", and unveil the Amazonian upper canopy as similar to Mediterranean vegetation habitats, hygrothermically stressed environments with leaf temperature at lethal limits and high levels of leaf sclerophylly.
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NASA Astrophysics Data System (ADS)
Armenteras, Dolors; Barreto, Joan Sebastian; Tabor, Karyn; Molowny-Horas, Roberto; Retana, Javier
2017-06-01
Tropical forests in NW Amazonia are highly threatened by the expansion of the agricultural frontier and subsequent deforestation. Fire is used, both directly and indirectly, in Brazilian Amazonia to propagate deforestation and increase forest accessibility. Forest fragmentation, a measure of forest degradation, is also attributed to fire occurrence in the tropics. However, outside the Brazilian Legal Amazonia the role of fire in increasing accessibility and forest fragmentation is less explored. In this study, we compared fire regimes in five countries that share this tropical biome in the most north-westerly part of the Amazon Basin (Venezuela, Colombia, Ecuador, Peru and Brazil). We analysed spatial differences in the timing of peak fire activity and in relation to proximity to roads and rivers using 12 years of MODIS active fire detections. We also distinguished patterns of fire in relation to forest fragmentation by analysing fire distance to the forest edge as a measure of fragmentation for each country. We found significant hemispheric differences in peak fire occurrence with the highest number of fires in the south in 2005 vs. 2007 in the north. Despite this, both hemispheres are equally affected by fire. We also found difference in peak fire occurrence by country. Fire peaked in February in Colombia and Venezuela, whereas it peaked in September in Brazil and Peru, and finally Ecuador presented two fire peaks in January and October. We confirmed the relationship between fires and forest fragmentation for all countries and also found significant differences in the distance between the fire and the forest edge for each country. Fires were associated with roads and rivers in most countries. These results can inform land use planning at the regional, national and subnational scales to minimize the contribution of road expansion and subsequent access to the Amazonian natural resources to fire occurrence and the associated deforestation and carbon emissions.
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Building genomic resources for Theobroma cacao
USDA-ARS?s Scientific Manuscript database
Theobroma cacao L (cacao: Malvaceae) is a small tree endemic to the Amazonian rain forest, where it most likely evolved. Cacao persists in populations of naturally outcrossing and inbreeding plants, as it is a species with a complex system of self-incompatibility, where only a fraction of the popul...
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The Amazon Basin in transition
Eric A. Davidson; Alessandro C. de Araujo; Paulo Artaxo; Jennifer K. Balch; I. Foster Brown; Mercedes M.C. Bustamente; Michael T. Coe; Ruth S. DeFriess; Michael Keller; Marcos Longo; J. William Munger; Wilfrid Schroeder; Britaldo Soares-Filho; Carlos M. Souza, Jr.; Steven C. Wofsy
2012-01-01
Agricultural expansion and climate variability have become important agents of disturbance in the Amazon basin. Recent studies have demonstrated considerable resilience of Amazonian forests to moderate annual drought, but they also show that interactions between deforestation, fire and drought potentially lead to losses of carbon storage and changes in regional...
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Tropical Deforestation in the Bolivian Amazon
NASA Technical Reports Server (NTRS)
Tucker, Compton J.; Steininger, Marc K.; Townshend, John R. G.; Killeen, Timothy R.; Desch, Arthur
2000-01-01
Landsat satellite images from the mid-1980s and early 1990s were used to map tropical forest extent and deforestation in approximately 800,000 sq km of Amazonian Bolivia. Forest cover extent, including tropical deciduous forest, totalled 472,000 sq km while the area of natural non-forest formations totalled 298,000 sq km. The area deforested totalled 15,000 sq km in the middle 1980s and 28,800 sq km by the early 1990s. The rate of tropical deforestation in the >1,000 mm/y precipitation forest zone of Bolivia was 2,200 sq km/y from 1985-1986 to 1992-1994. We document a spatially-concentrated "deforestation zone" in Santa Cruz Department where >60% of the Bolivian deforestation is occurring at an accelerating rate in areas of tropical deciduous dry forest.
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NASA Astrophysics Data System (ADS)
Colinvaux, P. A.; De Oliveira, P. E.; Bush, M. B.
2000-01-01
Plants respond to Pleistocene climatic change as species, not as associations or biomes. This has been demonstrated unequivocally by paleobotanical data for temperate latitudes. In the far richer vegetations of the tropics species populations also fluctuated independently in response to climatic forcing, from their longlasting glacial states to the patterns of brief interglacials like the present and back again. We use pollen data to reconstruct the vegetation of the Amazon basin in oxygen isotope stages 3 and 2 of the last glaciation in order to measure how the plant populations of the Amazon responded to the global warming at the onset of the Holocene. We find that plant communities of the neotropics vent copious pollen to lake sediments and that this pollen yields powerful signals for community composition. Three continuous sedimentary records reaching through oxygen isotope stage 2 are available from the Amazon lowlands, those from Carajas, Lake Pata and marine deposits off the mouth of the Amazon River. All three records yield pollen histories of remarkable constancy and stability. By comparing them with deposits of equal antiquity from the cerrado (savanna) of central Brazil, we show that most of the Amazon lowlands remained under forest throughout a glacial cycle. This forest was never fragmented by open vegetation as postulated by the refugia hypothesis. Instead the intact forest of glacial times included significant populations of plants that are now montane, suggesting that the global warming of the early Holocene resulted in the expulsion of heat intolerant plants from the lowland forest. Pollen data from the Amazonian flank of the Andes and from Pacific Panama provide evidence that populations of these heat intolerant plants survive the heat of interglacials in part by maintaining large populations at cooler montane altitudes. Our conclusion that the Amazon lowlands were forested in glacial times specifically refutes the hypothesis of Amazonian glacial aridity. Accordingly we examine the geomorphological evidence for glacial aridity and find it wanting. Of the three paleodune systems reported for tropical South America, that of NE Brazil was active in the Holocene as well as the Pleistocene. Parts of NE Brazil were actually moister than now in late-glacial times. Paleodunes in the Pantanal have never been seen on the ground, and those in the Orinoco Llanos are undated and may be of any age since the Tertiary. Arkosic sands in the Amazon fan deposits came from the Andean foothills or from down cutting by rivers and cannot be evidence of a former arid land surface. White sands of Amazonia formed as podzols, not by aeolian activity. Such Amazonian stone lines as have received critical scrutiny are concretionary pisolites in stratigraphic formations that are more than ten million years old. Although the Amazon was never arid, modeling cooler glacial tropics gives plausibility to a somewhat drier Amazon in glacial times, a concept given substance by pollen data for the movement of ecotones in Rondonia, by stream histories in the Bolivian Andes, and by evidence for lowered lake levels at Carajas and Lake Pata. But this reduced precipitation was never enough to fragment the forest in the Amazon lowlands themselves. Pleistocene mammals of the Napo river valley in Ecuador were able to live along the river system in a forested landscape. Our data suggest that the Amazon forests have been stable since the start of the Pleistocene, a fact that has contributed to the storage of vast diversity. The coming anthropogenic global warming and CO 2 enrichment will add to the global warming already endured by Amazon biota in the Holocene. We think it possible that the expulsion from the lowland forests of heat intolerant species is already complete and that the forest property of maintaining its own microhabitat will allow the high species richness to survive more global warming, provided large enough tracts of forest are preserved.
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NASA Astrophysics Data System (ADS)
Ribeiro, A. I.; Mello, G. F.; Longo, R. M.; Fengler, F. H.; Peche Filho, A., Sr.
2017-12-01
One of the greatest natural riches of Brazil is the Amazon rainforest. The Amazon region is known for its abundance of mineral resources, and may include topaz, oil, and especially cassiterite. In this scope, the mining sector in Brazil has great strategic importance because it accounts for approximately 30% of the country's exports with a mineral production of 40 billion dollars (Brazilian Mining Institute, 2015). In this scenario, as a consequence of mining, the Amazonian ecosystem has been undergoing a constant process of degradation. An important artifice in the exploitation of mineral resources is the rehabilitation and/or recovery of degraded areas. This recovery requires the establishment of degradation indicators and also the quality of the soil associated with its biota, since the Amazonian environment is dynamic, heterogeneous and complex in its physical, chemical and biological characteristics. In this way, this work presupposes that it is possible to characterize the different stages of recovery of tillage floor areas in deactivated cassiterite mines, within the Amazonian forest, in order to evaluate the interactions between the level of biological activity (Serrapilheira Height, Coefficient Metabolic, Basal Breath) and physical soil characteristics (aggregate DMG, Porosity, Total Soil Density, Moisture Content), through canonical correlation analysis. The results present correlations between the groups of indicators. Thus, from the use of the groups defined by canonical correlations, it was possible to identify the response of the set of physical and biological variables to the areas at different stages of recovery.
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Extremely long-distance seed dispersal by an overfished Amazonian frugivore.
Anderson, Jill T; Nuttle, Tim; Saldaña Rojas, Joe S; Pendergast, Thomas H; Flecker, Alexander S
2011-11-22
Throughout Amazonia, overfishing has decimated populations of fruit-eating fishes, especially the large-bodied characid, Colossoma macropomum. During lengthy annual floods, frugivorous fishes enter vast Amazonian floodplains, consume massive quantities of fallen fruits and egest viable seeds. Many tree and liana species are clearly specialized for icthyochory, and seed dispersal by fish may be crucial for the maintenance of Amazonian wetland forests. Unlike frugivorous mammals and birds, little is known about seed dispersal effectiveness of fishes. Extensive mobility of frugivorous fish could result in extremely effective, multi-directional, long-distance seed dispersal. Over three annual flood seasons, we tracked fine-scale movement patterns and habitat use of wild Colossoma, and seed retention in the digestive tracts of captive individuals. Our mechanistic model predicts that Colossoma disperses seeds extremely long distances to favourable habitats. Modelled mean dispersal distances of 337-552 m and maximum of 5495 m are among the longest ever reported. At least 5 per cent of seeds are predicted to disperse 1700-2110 m, farther than dispersal by almost all other frugivores reported in the literature. Additionally, seed dispersal distances increased with fish size, but overfishing has biased Colossoma populations to smaller individuals. Thus, overexploitation probably disrupts an ancient coevolutionary relationship between Colossoma and Amazonian plants.
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Extremely long-distance seed dispersal by an overfished Amazonian frugivore
Anderson, Jill T.; Nuttle, Tim; Saldaña Rojas, Joe S.; Pendergast, Thomas H.; Flecker, Alexander S.
2011-01-01
Throughout Amazonia, overfishing has decimated populations of fruit-eating fishes, especially the large-bodied characid, Colossoma macropomum. During lengthy annual floods, frugivorous fishes enter vast Amazonian floodplains, consume massive quantities of fallen fruits and egest viable seeds. Many tree and liana species are clearly specialized for icthyochory, and seed dispersal by fish may be crucial for the maintenance of Amazonian wetland forests. Unlike frugivorous mammals and birds, little is known about seed dispersal effectiveness of fishes. Extensive mobility of frugivorous fish could result in extremely effective, multi-directional, long-distance seed dispersal. Over three annual flood seasons, we tracked fine-scale movement patterns and habitat use of wild Colossoma, and seed retention in the digestive tracts of captive individuals. Our mechanistic model predicts that Colossoma disperses seeds extremely long distances to favourable habitats. Modelled mean dispersal distances of 337–552 m and maximum of 5495 m are among the longest ever reported. At least 5 per cent of seeds are predicted to disperse 1700–2110 m, farther than dispersal by almost all other frugivores reported in the literature. Additionally, seed dispersal distances increased with fish size, but overfishing has biased Colossoma populations to smaller individuals. Thus, overexploitation probably disrupts an ancient coevolutionary relationship between Colossoma and Amazonian plants. PMID:21429923
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Galbraith, David; Levy, Peter E; Sitch, Stephen; Huntingford, Chris; Cox, Peter; Williams, Mathew; Meir, Patrick
2010-08-01
*The large-scale loss of Amazonian rainforest under some future climate scenarios has generally been considered to be driven by increased drying over Amazonia predicted by some general circulation models (GCMs). However, the importance of rainfall relative to other drivers has never been formally examined. *Here, we conducted factorial simulations to ascertain the contributions of four environmental drivers (precipitation, temperature, humidity and CO(2)) to simulated changes in Amazonian vegetation carbon (C(veg)), in three dynamic global vegetation models (DGVMs) forced with climate data based on HadCM3 for four SRES scenarios. *Increased temperature was found to be more important than precipitation reduction in causing losses of Amazonian C(veg) in two DGVMs (Hyland and TRIFFID), and as important as precipitation reduction in a third DGVM (LPJ). Increases in plant respiration, direct declines in photosynthesis and increases in vapour pressure deficit (VPD) all contributed to reduce C(veg) under high temperature, but the contribution of each mechanism varied greatly across models. Rising CO(2) mitigated much of the climate-driven biomass losses in the models. *Additional work is required to constrain model behaviour with experimental data under conditions of high temperature and drought. Current models may be overly sensitive to long-term elevated temperatures as they do not account for physiological acclimation.
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Global biomass burning - Atmospheric, climatic, and biospheric implications
NASA Technical Reports Server (NTRS)
Levine, Joel S. (Editor)
1991-01-01
The present volume discusses the biomass burning (BMB) studies of the International Global Atmospheric Chemistry project, GEO satellite estimation of Amazonian BMB, remote sensing of BMB in West Africa with NOAA-AVHRR, an orbital view of the great Chinese fire of 1987, BMB's role in tropical rainforest reduction, CO and O3 measurements of BMB in the Amazon, effects of vegetation burning on the atmospheric chemistry of the Venezuelan savanna, an assessment of annually-burned biomass in Africa, and light hydrocarbon emissions from African savanna burnings. Also discussed are BMB in India, trace gas and particulate emissions from BMB in temperate ecosystems, ammonia and nitric acid emissions from wetlands and boreal forest fires, combustion emissions and satellite imagery of BMB, BMB in the perspective of the global carbon cycle, modeling trace-gas emissions from BMB, NO(x) emissions from BMB, and cloud-condensation nuclei from BMB.
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Decay of interspecific avian flock networks along a disturbance gradient in Amazonia.
Mokross, Karl; Ryder, Thomas B; Côrtes, Marina Corrêa; Wolfe, Jared D; Stouffer, Philip C
2014-02-07
Our understanding of how anthropogenic habitat change shapes species interactions is in its infancy. This is in large part because analytical approaches such as network theory have only recently been applied to characterize complex community dynamics. Network models are a powerful tool for quantifying how ecological interactions are affected by habitat modification because they provide metrics that quantify community structure and function. Here, we examine how large-scale habitat alteration has affected ecological interactions among mixed-species flocking birds in Amazonian rainforest. These flocks provide a model system for investigating how habitat heterogeneity influences non-trophic interactions and the subsequent social structure of forest-dependent mixed-species bird flocks. We analyse 21 flock interaction networks throughout a mosaic of primary forest, fragments of varying sizes and secondary forest (SF) at the Biological Dynamics of Forest Fragments Project in central Amazonian Brazil. Habitat type had a strong effect on network structure at the levels of both species and flock. Frequency of associations among species, as summarized by weighted degree, declined with increasing levels of forest fragmentation and SF. At the flock level, clustering coefficients and overall attendance positively correlated with mean vegetation height, indicating a strong effect of habitat structure on flock cohesion and stability. Prior research has shown that trophic interactions are often resilient to large-scale changes in habitat structure because species are ecologically redundant. By contrast, our results suggest that behavioural interactions and the structure of non-trophic networks are highly sensitive to environmental change. Thus, a more nuanced, system-by-system approach may be needed when thinking about the resiliency of ecological networks.
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Ecosystem state shifts during long-term development of an Amazonian peatland.
Swindles, Graeme T; Morris, Paul J; Whitney, Bronwen; Galloway, Jennifer M; Gałka, Mariusz; Gallego-Sala, Angela; Macumber, Andrew L; Mullan, Donal; Smith, Mark W; Amesbury, Matthew J; Roland, Thomas P; Sanei, Hamed; Patterson, R Timothy; Sanderson, Nicole; Parry, Lauren; Charman, Dan J; Lopez, Omar; Valderamma, Elvis; Watson, Elizabeth J; Ivanovic, Ruza F; Valdes, Paul J; Turner, T Edward; Lähteenoja, Outi
2018-02-01
The most carbon (C)-dense ecosystems of Amazonia are areas characterized by the presence of peatlands. However, Amazonian peatland ecosystems are poorly understood and are threatened by human activities. Here, we present an investigation into long-term ecohydrological controls on C accumulation in an Amazonian peat dome. This site is the oldest peatland yet discovered in Amazonia (peat initiation ca. 8.9 ka BP), and developed in three stages: (i) peat initiated in an abandoned river channel with open water and aquatic plants; (ii) inundated forest swamp; and (iii) raised peat dome (since ca. 3.9 ka BP). Local burning occurred at least three times in the past 4,500 years. Two phases of particularly rapid C accumulation (ca. 6.6-6.1 and ca. 4.9-3.9 ka BP), potentially resulting from increased net primary productivity, were seemingly driven by drier conditions associated with widespread drought events. The association of drought phases with major ecosystem state shifts (open water wetland-forest swamp-peat dome) suggests a potential climatic control on the developmental trajectory of this tropical peatland. A third drought phase centred on ca. 1.8-1.1 ka BP led to markedly reduced C accumulation and potentially a hiatus during the peat dome stage. Our results suggest that future droughts may lead to phases of rapid C accumulation in some inundated tropical peat swamps, although this can lead ultimately to a shift to ombrotrophy and a subsequent return to slower C accumulation. Conversely, in ombrotrophic peat domes, droughts may lead to reduced C accumulation or even net loss of peat. Increased surface wetness at our site in recent decades may reflect a shift towards a wetter climate in western Amazonia. Amazonian peatlands represent important carbon stores and habitats, and are important archives of past climatic and ecological information. They should form key foci for conservation efforts. © 2017 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.
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Brazil's Amazonian dams: Ecological and socioeconomic impacts
NASA Astrophysics Data System (ADS)
Fearnside, P. M.
2016-12-01
Brazil's 2015-2024 Energy Expansion Plan calls for 11 hydroelectric dams with installed capacity ≥ 30 MW in the country's Amazon region. Dozens of other large dams are planned beyond this time horizon, and dams with < 30 MW installed capacity number in the hundreds. Amazonian dams have substantial environmental and socioeconomic impacts. Loss of forest to flooding is one, the Balbina and Tucuruí Dams being examples (each 3000 km2). If the Babaquara/Altamira Dam is built it will flood as much forest as both of these combined. Some planned dams imply loss of forest in protected areas, for example on the Tapajós River. Aquatic and riparian ecosystems are lost, including unique biodiversity. Endemic fish species in rapids on the Xingu and Tapajós Rivers are examples. Fish migrations are blocked, such as the commercially important "giant catfish" of the Madeira River. Dams emit greenhouse gases, including CO2 from the trees killed and CH4 from decay under anoxic conditions at the bottom of reservoirs. Emissions can exceed those from fossil-fuel generation, particularly over the 20-year period during which global emissions must be greatly reduced to meet 1.5-2°C limit agreed in Paris. Carbon credit for dams under the Climate Convention causes further net emission because the dams are not truly "additional." Anoxic environments in stratified reservoirs cause methylation of mercury present in Amazonian soils, which concentrates in fish, posing a health risk to human consumers. Population displacement is a major impact; for example, the Marabá Dam would displace 40,000 people, mostly traditional riverside dwellers (ribeirinhos). Various dams impact indigenous peoples, such as the Xingu River dams (beginning with Belo Monte) and the São Luiz do Tapajós and Chacorão Dams on the Tapajós River. Brazil has many energy options other than dams. Much energy use has little benefit for the country, such as exporting aluminum. Electric showerheads use 5% of the country's power. Losses in transmission lines (20%) are far above global averages and can be expected to increase as Amazonian hydroelectric dams far from consumer centers come on line. Brazil has tremendous wind and solar potential, but these do not have the same priority as dams. At the root of many questionable policies is a decision-making process in need of reform.
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NASA Astrophysics Data System (ADS)
Chavana-Bryant, C.; Malhi, Y.; Gerard, F.
2015-12-01
Leaf aging is a fundamental driver of changes in leaf traits, thereby, regulating ecosystem processes and remotely-sensed canopy dynamics. Leaf age is particularly important for carbon-rich tropical evergreen forests, as leaf demography (leaf age distribution) has been proposed as a major driver of seasonal productivity in these forests. We explore leaf reflectance as a tool to monitor leaf age and develop a novel spectra-based (PLSR) model to predict age using data from a phenological study of 1,072 leaves from 12 lowland Amazonian canopy tree species in southern Peru. Our results demonstrate monotonic decreases in LWC and Pmass and increase in LMA with age across species; Nmass and Cmassshowed monotonic but species-specific age responses. Spectrally, we observed large age-related variation across species, with the most age-sensitive spectral domains found to be: green peak (550nm), red edge (680-750 nm), NIR (700-850 nm), and around the main water absorption features (~1450 and ~1940 nm). A spectra-based model was more accurate in predicting leaf age (R2= 0.86; %RMSE= 33) compared to trait-based models using single (R2=0.07 to 0.73; %RMSE=7 to 38) and multiple predictors (step-wise analysis; R2=0.76; %RMSE=28). Spectral and trait-based models established a physiochemical basis for the spectral age model. The relative importance of the traits modifying the leaf spectra of aging leaves was: LWC>LMA>Nmass>Pmass,&Cmass. Vegetation indices (VIs), including NDVI, EVI2, NDWI and PRI were all age-dependent. This study highlights the importance of leaf age as a mediator of leaf traits, provides evidence of age-related leaf reflectance changes that have important impacts on VIs used to monitor canopy dynamics and productivity, and proposes a new approach to predicting and monitoring leaf age with important implications for remote sensing.
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Slow growth rates of Amazonian trees: Consequences for carbon cycling
Vieira, Simone; Trumbore, Susan; Camargo, Plinio B.; Selhorst, Diogo; Chambers, Jeffrey Q.; Higuchi, Niro; Martinelli, Luiz Antonio
2005-01-01
Quantifying age structure and tree growth rate of Amazonian forests is essential for understanding their role in the carbon cycle. Here, we use radiocarbon dating and direct measurement of diameter increment to document unexpectedly slow growth rates for trees from three locations spanning the Brazilian Amazon basin. Central Amazon trees, averaging only ≈1mm/year diameter increment, grow half as fast as those from areas with more seasonal rainfall to the east and west. Slow growth rates mean that trees can attain great ages; across our sites we estimate 17-50% of trees with diameter >10 cm have ages exceeding 300 years. Whereas a few emergent trees that make up a large portion of the biomass grow faster, small trees that are more abundant grow slowly and attain ages of hundreds of years. The mean age of carbon in living trees (60-110 years) is within the range of or slightly longer than the mean residence time calculated from C inventory divided by annual C allocation to wood growth (40-100 years). Faster C turnover is observed in stands with overall higher rates of diameter increment and a larger fraction of the biomass in large, fast-growing trees. As a consequence, forests can recover biomass relatively quickly after disturbance, whereas recovering species composition may take many centuries. Carbon cycle models that apply a single turnover time for carbon in forest biomass do not account for variations in life strategy and therefore may overestimate the carbon sequestration potential of Amazon forests. PMID:16339903
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Environmental Controls of Soil Organic Carbon in Soils Across Amazonia
NASA Astrophysics Data System (ADS)
Quesada, Carlos Alberto; Paz, Claudia; Phillips, Oliver; Nonato Araujo Filho, Raimundo; Lloyd, Jon
2015-04-01
Amazonian forests store and cycle a significant amount of carbon on its soils and vegetation. Yet, Amazonian forests are now subject to strong environmental pressure from both land use and climate change. Some of the more dramatic model projections for the future of the Amazon predict a major change in precipitation followed by savanization of most currently forested areas, resulting in major carbon losses to the atmosphere. However, how soil carbon stocks will respond to climatic and land use changes depend largely on how soil carbon is stabilized. Amazonian soils are highly diverse, being very variable in their weathering levels and chemical and physical properties, and thus it is important to consider how the different soils of the Basin stabilize and store soil organic carbon (SOC). The wide variation in soil weathering levels present in Amazonia, suggests that soil groups with contrasting pedogenetic development should differ in their predominant mechanism of SOC stabilization. In this study we investigated the edaphic, mineralogical and climatic controls of SOC concentration in 147 pristine forest soils across nine different countries in Amazonia, encompassing 14 different WRB soil groups. Soil samples were collected in 1 ha permanent plots used for forest dynamics studies as part of the RAINFOR project. Only 0-30 cm deep averages are reported here. Soil samples were analyzed for carbon and nitrogen and for their chemical (exchangeable bases, phosphorus, pH) and physical properties, (particle size, bulk density) and mineralogy through standard selective dissolution techniques (Fe and Al oxides) and by semi-quantitative X-Ray diffraction. In Addition, selected soils from each soil group had SOC fractionated by physical and chemical techniques. Our results indicate that different stabilization mechanisms are responsible for SOC stabilization in Amazonian soils with contrasting pedogenetic level. Ferralsols and Acrisols were found to have uniform mineralogy (kaolinitic) and thus the clay plus silt fraction was the best correlate for SOC but with crystalline iron oxides (dithionite-citrate minus ammonium oxalate - oxalic acid extractable iron) being also correlated to SOC in these soils (R2 = 0.74). Most of SOC in these soils was found on the clay+silt fraction and in stable, clay rich aggregates. However, SOC of high activity clays and other less weathered soils such as Alisols, Cambisols and Plinthosols showed no correlation with particle size or iron oxides, being mostly stabilized by aluminium complexes. We found SOC of these soils to be better explained by a three way interaction among soil pH, carbon quality and dithionite-citrate extractable Al (R2 = 0.85). Consistent with this observation, SOC in the less weathered soils was mostly found in the colloidal fraction (75%). SOC of Podzols and Arenosols on the other hand had only a small but significant influence from their clay plus silt fraction (R2 = 0.31), with particulate organic matter accounting for most of its SOC.
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GuiaTreeKey, a multi-access electronic key to identify tree genera in French Guiana.
Engel, Julien; Brousseau, Louise; Baraloto, Christopher
2016-01-01
The tropical rainforest of Amazonia is one of the most species-rich ecosystems on earth, with an estimated 16000 tree species. Due to this high diversity, botanical identification of trees in the Amazon is difficult, even to genus, often requiring the assistance of parataxonomists or taxonomic specialists. Advances in informatics tools offer a promising opportunity to develop user-friendly electronic keys to improve Amazonian tree identification. Here, we introduce an original multi-access electronic key for the identification of 389 tree genera occurring in French Guiana terra-firme forests, based on a set of 79 morphological characters related to vegetative, floral and fruit characters. Its purpose is to help Amazonian tree identification and to support the dissemination of botanical knowledge to non-specialists, including forest workers, students and researchers from other scientific disciplines. The electronic key is accessible with the free access software Xper ², and the database is publicly available on figshare: https://figshare.com/s/75d890b7d707e0ffc9bf (doi: 10.6084/m9.figshare.2682550).
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Wood decomposition in Amazonian hydropower reservoirs: An additional source of greenhouse gases
NASA Astrophysics Data System (ADS)
Abril, Gwenaël; Parize, Marcelo; Pérez, Marcela A. P.; Filizola, Naziano
2013-07-01
Amazonian hydroelectric reservoirs produce abundant carbon dioxide and methane from large quantities of flooded biomass that decompose anaerobically underwater. Emissions are extreme the first years after impounding and progressively decrease with time. To date, only water-to-air fluxes have been considered in these estimates. Here, we investigate in two Amazonian reservoirs (Balbina and Petit Saut) the fate of above water standing dead trees, by combining a qualitative analysis of wood state and density through time and a quantitative analysis of the biomass initially flooded. Dead wood was much more decomposed in the Balbina reservoir 23 years after flooding than in the Petit Saut reservoir 10 years after flooding. Termites apparently played a major role in wood decomposition, occurring mainly above water, and resulting in a complete conversion of this carbon biomass into CO2 and CH4 at a timescale much shorter than reservoir operation. The analysis of pre-impounding wood biomass reveals that above-water decomposition in Amazonian reservoirs is a large, previously unrecognized source of carbon emissions to the atmosphere, representing 26-45% of the total reservoir flux integrated over 100 years. Accounting for both below- and above-water fluxes, we could estimate that each km2 of Amazonian forest converted to reservoir would emit over 140 Gg CO2-eq in 100 years. Hydropower plants in the Amazon should thus generate 0.25-0.4 MW h per km2 flooded area to produce lower greenhouse gas emissions than gas power plants. They also have the disadvantage to emit most of their greenhouse gases the earliest years of operation.
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Large-scale climatic and geophysical controls on the leaf economics spectrum.
Asner, Gregory P; Knapp, David E; Anderson, Christopher B; Martin, Roberta E; Vaughn, Nicholas
2016-07-12
Leaf economics spectrum (LES) theory suggests a universal trade-off between resource acquisition and storage strategies in plants, expressed in relationships between foliar nitrogen (N) and phosphorus (P), leaf mass per area (LMA), and photosynthesis. However, how environmental conditions mediate LES trait interrelationships, particularly at large biospheric scales, remains unknown because of a lack of spatially explicit data, which ultimately limits our understanding of ecosystem processes, such as primary productivity and biogeochemical cycles. We used airborne imaging spectroscopy and geospatial modeling to generate, to our knowledge, the first biospheric maps of LES traits, here centered on 76 million ha of Andean and Amazonian forest, to assess climatic and geophysical determinants of LES traits and their interrelationships. Elevation and substrate were codominant drivers of leaf trait distributions. Multiple additional climatic and geophysical factors were secondary determinants of plant traits. Anticorrelations between N and LMA followed general LES theory, but topo-edaphic conditions strongly mediated and, at times, eliminated this classic relationship. We found no evidence for simple P-LMA or N-P trade-offs in forest canopies; rather, we mapped a continuum of N-P-LMA interactions that are sensitive to elevation and temperature. Our results reveal nested climatic and geophysical filtering of LES traits and their interrelationships, with important implications for predictions of forest productivity and acclimation to rapid climate change.
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Ribas, Camila C.; Aleixo, Alexandre; Nogueira, Afonso C. R.; Miyaki, Cristina Y.; Cracraft, Joel
2012-01-01
Many hypotheses have been proposed to explain high species diversity in Amazonia, but few generalizations have emerged. In part, this has arisen from the scarcity of rigorous tests for mechanisms promoting speciation, and from major uncertainties about palaeogeographic events and their spatial and temporal associations with diversification. Here, we investigate the environmental history of Amazonia using a phylogenetic and biogeographic analysis of trumpeters (Aves: Psophia), which are represented by species in each of the vertebrate areas of endemism. Their relationships reveal an unforeseen ‘complete’ time-slice of Amazonian diversification over the past 3.0 Myr. We employ this temporally calibrated phylogeny to test competing palaeogeographic hypotheses. Our results are consistent with the establishment of the current Amazonian drainage system at approximately 3.0–2.0 Ma and predict the temporal pattern of major river formation over Plio-Pleistocene times. We propose a palaeobiogeographic model for the last 3.0 Myr of Amazonian history that has implications for understanding patterns of endemism, the temporal history of Amazonian diversification and mechanisms promoting speciation. The history of Psophia, in combination with new geological evidence, provides the strongest direct evidence supporting a role for river dynamics in Amazonian diversification, and the absence of such a role for glacial climate cycles and refugia. PMID:21795268
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Self-amplified Amazon forest loss due to vegetation-atmosphere feedbacks.
Zemp, Delphine Clara; Schleussner, Carl-Friedrich; Barbosa, Henrique M J; Hirota, Marina; Montade, Vincent; Sampaio, Gilvan; Staal, Arie; Wang-Erlandsson, Lan; Rammig, Anja
2017-03-13
Reduced rainfall increases the risk of forest dieback, while in return forest loss might intensify regional droughts. The consequences of this vegetation-atmosphere feedback for the stability of the Amazon forest are still unclear. Here we show that the risk of self-amplified Amazon forest loss increases nonlinearly with dry-season intensification. We apply a novel complex-network approach, in which Amazon forest patches are linked by observation-based atmospheric water fluxes. Our results suggest that the risk of self-amplified forest loss is reduced with increasing heterogeneity in the response of forest patches to reduced rainfall. Under dry-season Amazonian rainfall reductions, comparable to Last Glacial Maximum conditions, additional forest loss due to self-amplified effects occurs in 10-13% of the Amazon basin. Although our findings do not indicate that the projected rainfall changes for the end of the twenty-first century will lead to complete Amazon dieback, they suggest that frequent extreme drought events have the potential to destabilize large parts of the Amazon forest.
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Self-amplified Amazon forest loss due to vegetation-atmosphere feedbacks
NASA Astrophysics Data System (ADS)
Zemp, Delphine Clara; Schleussner, Carl-Friedrich; Barbosa, Henrique M. J.; Hirota, Marina; Montade, Vincent; Sampaio, Gilvan; Staal, Arie; Wang-Erlandsson, Lan; Rammig, Anja
2017-03-01
Reduced rainfall increases the risk of forest dieback, while in return forest loss might intensify regional droughts. The consequences of this vegetation-atmosphere feedback for the stability of the Amazon forest are still unclear. Here we show that the risk of self-amplified Amazon forest loss increases nonlinearly with dry-season intensification. We apply a novel complex-network approach, in which Amazon forest patches are linked by observation-based atmospheric water fluxes. Our results suggest that the risk of self-amplified forest loss is reduced with increasing heterogeneity in the response of forest patches to reduced rainfall. Under dry-season Amazonian rainfall reductions, comparable to Last Glacial Maximum conditions, additional forest loss due to self-amplified effects occurs in 10-13% of the Amazon basin. Although our findings do not indicate that the projected rainfall changes for the end of the twenty-first century will lead to complete Amazon dieback, they suggest that frequent extreme drought events have the potential to destabilize large parts of the Amazon forest.
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Self-amplified Amazon forest loss due to vegetation-atmosphere feedbacks
Zemp, Delphine Clara; Schleussner, Carl-Friedrich; Barbosa, Henrique M. J.; Hirota, Marina; Montade, Vincent; Sampaio, Gilvan; Staal, Arie; Wang-Erlandsson, Lan; Rammig, Anja
2017-01-01
Reduced rainfall increases the risk of forest dieback, while in return forest loss might intensify regional droughts. The consequences of this vegetation–atmosphere feedback for the stability of the Amazon forest are still unclear. Here we show that the risk of self-amplified Amazon forest loss increases nonlinearly with dry-season intensification. We apply a novel complex-network approach, in which Amazon forest patches are linked by observation-based atmospheric water fluxes. Our results suggest that the risk of self-amplified forest loss is reduced with increasing heterogeneity in the response of forest patches to reduced rainfall. Under dry-season Amazonian rainfall reductions, comparable to Last Glacial Maximum conditions, additional forest loss due to self-amplified effects occurs in 10–13% of the Amazon basin. Although our findings do not indicate that the projected rainfall changes for the end of the twenty-first century will lead to complete Amazon dieback, they suggest that frequent extreme drought events have the potential to destabilize large parts of the Amazon forest. PMID:28287104
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Unexpected High Diversity of Galling Insects in the Amazonian Upper Canopy: The Savanna Out There
Julião, Genimar R.; Venticinque, Eduardo M.; Fernandes, G. Wilson; Price, Peter W.
2014-01-01
A relatively large number of studies reassert the strong relationship between galling insect diversity and extreme hydric and thermal status in some habitats, and an overall pattern of a greater number of galling species in the understory of scleromorphic vegetation. We compared galling insect diversity in the forest canopy and its relationship with tree richness among upland terra firme, várzea, and igapó floodplains in Amazonia, Brazil. The soils of these forest types have highly different hydric and nutritional status. Overall, we examined the upper layer of 1,091 tree crowns. Galling species richness and abundance were higher in terra firme forests compared to várzea and igapó forests. GLM-ANCOVA models revealed that the number of tree species sampled in each forest type was determinant in the gall-forming insect diversity. The ratio between galling insect richness and number of tree species sampled (GIR/TSS ratio) was higher in the terra firme forest and in seasonally flooded igapó, while the várzea presented the lowest GIR/TSS ratio. In this study, we recorded unprecedented values of galling species diversity and abundance per sampling point. The GIR/TSS ratio from várzea was approximately 2.5 times higher than the highest value of this ratio ever reported in the literature. Based on this fact, we ascertained that várzea and igapó floodplain forests (with lower GIA and GIR), together with the speciose terra firme galling community emerge as the gall diversity apex landscape among all biogeographic regions already investigated. Contrary to expectation, our results also support the “harsh environment hypothesis”, and unveil the Amazonian upper canopy as similar to Mediterranean vegetation habitats, hygrothermically stressed environments with leaf temperature at lethal limits and high levels of leaf sclerophylly. PMID:25551769
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Drought responses of flood-tolerant trees in Amazonian floodplains
Parolin, Pia; Lucas, Christine; Piedade, Maria Teresa F.; Wittmann, Florian
2010-01-01
Background Flood-tolerant tree species of the Amazonian floodplain forests are subjected to an annual dry period of variable severity imposed when low river-water levels coincide with minimal precipitation. Although the responses of these species to flooding have been examined extensively, their responses to drought, in terms of phenology, growth and physiology, have been neglected hitherto, although some information is found in publications that focus on flooding. Scope The present review examines the dry phase of the annual flooding cycle. It consolidates existing knowledge regarding responses to drought among adult trees and seedlings of many Amazonian floodplain species. Main Findings Flood-tolerant species display variable physiological responses to dry periods and drought that indicate desiccation avoidance, such as reduced photosynthetic activity and reduced root respiration. However, tolerance and avoidance strategies for drought vary markedly among species. Drought can substantially decrease growth, biomass and photosynthetic activity among seedlings in field and laboratory studies. When compared with the responses to flooding, drought can impose higher seedling mortality and slower growth rates, especially among evergreen species. Results indicate that tolerance and avoidance strategies for drought vary markedly between species. Both seedling recruitment and photosynthetic activity are affected by drought, Conclusions For many species, the effects of drought can be as important as flooding for survival and growth, particularly at the seedling phase of establishment, ultimately influencing species composition. In the context of climate change and predicted decreases in precipitation in the Amazon Basin, the effects of drought on plant physiology and species distribution in tropical floodplain forest ecosystems should not be overlooked. PMID:19880423
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Tiger-Moths in Savannas in Eastern Amazon: First Assessment of Diversity and Seasonal Aspects.
Valente, D M P; Zenker, M M; Teston, J A
2018-01-06
Biodiversity knowledge on insects is urgently needed due to the ever growing demand for food and the consequent deforestation process and loss of natural habitats in many understudied tropical regions. In this paper, we describe the outcome of a biodiversity research on tiger moths performed for the first time in a poorly studied Amazonian landscape-the savanna. We sampled tiger moths monthly with UV automatic light traps for 12 consecutive months in two sampling points in an area of savanna in eastern Amazon, and we compared our results to previously available data for eastern Amazon. We found a total of 91 species of which 80 were identified to species level. The most species-rich subtribes were Phaegopterina and Euchromiina with 32 species each. Species richness and abundance did not differ among sampling sites, but in general the species richness was higher during the dry season while abundance was higher during the wet season. This seasonal diversity pattern differs from the most common patterns recorded for savannas in other parts of the world. The species composition also changed in wet and dry seasons and correlated significantly with temperature and relative humidity. Our results suggest that the alpha diversity of the Amazonian savannas in our sampling area is lower than that in nearby rain forests and similar to that in agriculturally disturbed areas surrounded by rain forests. However, the species composition differed considerably from natural and disturbed areas. These results highlight the need of basic biodiversity surveys of insects in Amazonian savannas.
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Fear-based niche shifts in neotropical birds.
Martínez, Ari E; Parra, Eliseo; Muellerklein, Oliver; Vredenburg, Vance T
2018-06-01
Predation is a strong ecological force that shapes animal communities through natural selection. Recent studies have shown the cascading effects of predation risk on ecosystems through changes in prey behavior. Minimizing predation risk may explain why multiple prey species associate together in space and time. For example, mixed-species flocks that have been widely documented from forest systems, often include birds that eavesdrop on sentinel species (alarm calling heterospecifics). Sentinel species may be pivotal in (1) allowing flocking species to forage in open areas within forests that otherwise incur high predation risk, and (2) influencing flock occurrence (the amount of time species spend with a flock). To test this, we conducted a short-term removal experiment in an Amazonian lowland rainforest to test whether flock habitat use and flock occurrence was influenced by sentinel presence. Antshrikes (genus Thamnomanes) act as sentinels in Amazonian mixed-species flocks by providing alarm calls widely used by other flock members. The alarm calls provide threat information about ambush predators such as hawks and falcons which attack in flight. We quantified home range behavior, the forest vegetation profile used by flocks, and the proportion occurrence of other flocking species, both before and after removal of antshrikes from flocks. We found that when sentinel species were removed, (1) flock members shifted habitat use to lower risk habitats with greater vegetation cover, and (2) species flock occurrence decreased. We conclude that eavesdropping on sentinel species may allow other species to expand their realized niche by allowing them to safely forage in high-risk habitats within the forest. In allowing species to use extended parts of the forest, sentinel species may influence overall biodiversity across a diverse landscape. © 2018 by the Ecological Society of America.
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AmeriFlux BR-Sa1 Santarem-Km67-Primary Forest
Saleska, Scott [University of Arizona
2016-01-01
This is the AmeriFlux version of the carbon flux data for the site BR-Sa1 Santarem-Km67-Primary Forest. Site Description - The LBA Tapajos KM67 Mature Forest site is located in the Tapajos National Forest, a 450,000 ha closed-canopy upland forest in Amazonian Brazil. Bounded by the Tapajos River in the west and highway BR-163 to the east, the tower is located on a flat plateau (or planalto) that extends up to 150 km to the north, south, and east. Within the confines of the National Forest, anthropogenic disturbances are limited to a few small hunting trails. The surrounding stand is classified as primary or "old-growth"" predominantly by its uneven age distribution, emergent trees, numerous epiphytes and abundant large logs. In 2007 falling trees hit the tower guy wires rendering all instrumentation in-operational. After a complete restoration tower measurements resumed in August of 2008.
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Impact Of Selfing On The Inference Of Demographic History From Whole Genomes In Theobroma cacao L.
USDA-ARS?s Scientific Manuscript database
Theobroma cacao L (cacao: Malvaceae) is a small tree found naturally in the Amazonian rain forest. An interesting feature of cacao is that it persists in populations of naturally outcrossing and inbreeding plants, as it is a species with a complex system of self-incompatibility, where a fraction of...
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Draft genome sequence of the D-Xylose-Fermenting yeast Spathaspora xylofermentans UFMG-HMD23.3
USDA-ARS?s Scientific Manuscript database
Here, we report the draft genome sequence of the yeast Spathaspora xylofermentans UFMG-HMD23.3 (CBMAI 1427=CBS 12681), a D-xylose fermenting yeast isolated from the Amazonian forest. The genome consists of 298 contigs, with a total size of 15.1 Mb, including the mitochondrial genome, and 5,948 predi...
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Proof of the Post-drought Effect of Amazonian Forests from Space
NASA Astrophysics Data System (ADS)
Yang, Y.; Saatchi, S. S.; Xu, L.; Yu, Y.; Myneni, R. B.; Knyazikhin, Y.; CHOI, S.
2015-12-01
In 2005, the tropical forests in Amazonia went through a severe drought event across the entire basin. There have been conflict reports on the drought impact on vegetation and the issue was never settled due to limited ground truth. Remote sensing data have been used but often questioned for signal saturation, data quality, or atmosphere contamination. The quantification of carbon changes in this vast terrestrial carbon pool, especially the post-drought effect, is difficult but essential. Lidar measurements, which are regarded as the accurate retrieval of canopy vertical structure, give us the opportunity to quantify the carbon changes for this severe event. Here, we use the lidar waveforms measured from the GLAS sensor from 2004 to 2007 to calculate the vertical profiles of Amazonian forests and their associated carbon stock. After careful quality-filtering, removal of seasonal effect, as well as uncertainty reduction through spatial averaging and random sampling, we find that the mean canopy height in Amazon has much higher reduction from 2006 to 2007 compared to either the drought year from 2004 to 2005, or the immediate post-drought change from 2005 to 2006, demonstrating a lagged effect of drought. Our estimation of carbon loss from model calculation also show that 2005 drought had an significant impact on the carbon exchange, and emissions from post drought disturbance may match the emissions of annual deforestation from Amazonia.
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Predicting anthropogenic soils across the Amazonia
NASA Astrophysics Data System (ADS)
Mcmichael, C.; Palace, M. W.; Bush, M. B.; Braswell, B. H.; Hagen, S. C.; Silman, M.; Neves, E.; Czarnecki, C.
2012-12-01
Hidden under the forest canopy in lowland Amazonia are nutrient-enriched soils, called terra pretas (or Amazonian black earths), which were formed by prehistoric indigenous populations. These anthrosols are in stark contrast to typical nutrient-poor Amazonian soils, and have retained increased nutrient levels for hundreds of years. Because of their long-term nutrient retaining ability, terra pretas may be crucial for developing sustainable agricultural practices in Amazonia, especially given the deforestation necessary for traditional slash-and-burn systems. However, the frequency and distribution of terra preta soils across the landscape remains debatable, and archaeologists have estimated that terra pretas cover anywhere from 0.1% to 10% of the lowland Amazonian forests. The highest concentration of terra preta soils has been found along the central and eastern portions of the Amazon River and its major tributaries, but whether this is a true pattern or simply reflects sampling bias remains unknown. A possible explanation is that specific environmental or biotic conditions were preferred for human settlement and terra preta formation. Here, we use environmental parameters to predict the probabilities of terra preta soils across lowland Amazonian forests. We compiled a database of 2708 sites across Amazonia, including locations that contain terra pretas (n = 917), and those that are known to be terra preta-free (n = 1791). More than 20 environmental variables, including precipitation, elevation, slope, soil fertility, and distance to river were converted into 90-m resolution raster images across Amazonia and used to model the probability of terra preta occurrence. The relationship between the predictor variables and the occurrence of terra preta was examined using three modeling techniques: logistic regression, auto-logistic regression, and maximum entropy estimations. All three techniques provided similar predictions for terra preta distributions and the amount of area covered by terra preta. Distance to river, locations of bluffs, elevation, and soil fertility were important factors in determining distributions of terra preta, while other environmental variables had less effect. Terra pretas were most likely to be found in central and eastern Amazonia near the confluences of the Amazon River and its major tributaries. Within this general area of higher probability, terra pretas are most likely found atop the bluffs overlooking the rivers as opposed to lying on the floodplain. Interestingly, terra pretas are more probable in areas with less-fertile and more highly weathered soils. Although all three modeling techniques provided similar predictions of terra preta across Amazonia, we suggest that maximum entropy modeling is the best technique to predict anthropogenic soils across the vast Amazonian landscape. The auto-logistic regression corrects for spatial autocorrelation inherent to archaeological surveys, but still requires absence data, which was collected at different times and on different spatial scales than the presence data. The maximum entropy model requires presence only data, accounts for spatial autocorrelation, and is not affected by the differential soil sampling techniques.
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NASA Astrophysics Data System (ADS)
Davidson, Eric A.; Neill, Christopher; Krusche, Alex V.; Ballester, Victoria V. R.; Markewitz, Daniel; Figueiredo, Ricardo de O.
Rates of deforestation in the Amazon region have been accelerating, but the quantity and timing of nutrient losses from forested and deforested ecosystems are poorly understood. This paper investigates the broad variation in soil properties of the Amazon Basin as they influence transfers of plant nutrients from the terrestrial biosphere to the atmosphere and the aquatic biosphere. The dominant lowland soils are highly weathered Oxisols and Ultisols, but significant areas of Alfisols also exist, resulting in a wide range of weatherable primary minerals. Despite this considerable variation among Amazonian soils, a common feature in most mature lowland Amazonian forests is a conservative P cycle and excess N availability. In cattle pastures and secondary forests, however, low rates of internal terrestrial N cycling, low N export to streams, and low gaseous N emissions from soils are common, due to significant previous losses of N through repeated fire. Export of P to streams may increase or remain nearly undetectable after forest-to-pasture conversion, depending on soil type. Oxisols exhibit very low P export, whereas increased P export to pasture streams has been observed in Ultisols of western Amazonia. Calcium is mostly retained in terrestrial ecosystems following deforestation, although increased inputs to streams can be detected when background fluxes are naturally low. Because soil mineralogy and soil texture are both variable and important, the effects of land-use change on nutrient export to aquatic ecosystems and to the atmosphere must be understood within the context of varying soil properties across the Amazon Basin.
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NASA Astrophysics Data System (ADS)
Alves, E. G.; Batalha, S. S. A.; Park, J. H.; Seco, R.; Tota, J.; Santana, R. A. S. D.; Guenther, A. B.; Kim, S.; Smith, J. N.; Souza, R. A. F. D.
2014-12-01
Biogenic Volatile Organic Compounds (BVOCs) play an important role in atmospheric chemistry and biogeochemical cycles. It is known that tropical forests are the biggest source of the dominant BVOCs (i.e. isoprene and monoterpenes) emitted to the atmosphere. Nevertheless, Amazonian rainforest, the world's largest tropical rainforest, has been poorly explored for isoprene and monoterpene emissions. Recently (June and July 2014), we deployed a PTR-TOF-MS (Proton Transfer Reaction - Time of Flight - Mass Spectrometer) to quantify isoprene and monoterpene emissions using the eddy covariance flux method at the FLONA Tapajos (Floresta Nacional do Tapajos; Tapajos National Forest) in the eastern central Amazon rainforest, Santarem-PA, Brazil. The sample inlet and a 3D-sonic anemometer were located above the forest canopy (~65m), and the air was sampled through a long Teflon tube (100m) with high flow rate (40L/min) to the PTR-TOF-MS. From preliminary results for the first 3 days, concentrations and fluxes of m/z 69 (isoprene; C5H8-H+) and m/z 137 (total monoterpenes; C10H16-H+) showed a clear circadian cycle (high during daytime and low at nighttime), suggesting the emissions of these compounds are light and temperature dependent. Our study provides the first PTR-TOF-MS flux observations of isoprene and total monoterpenes at the Flona Tapajos. Moreover, since there are variations on the emissions, when comparing different environments of the huge Amazon basin, these results from eastern central Amazonia will contribute to improving regional and global BVOC emission model estimates.
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NASA Astrophysics Data System (ADS)
Zhang, Y.; Zeng, Z.; Piao, S.
2014-12-01
Tropical vegetation plays an essential role for global biogeochemical cycles. An abundant literature focused on the vegetation dynamics in Amazon. It is shown that the Amazonian rainforest is strongly controlled by radiation, even during dry season. However, only few researches deal with tropical rainforest in Southeast Asia; the vegetation dynamics in Southeast Asia remain poorly understood. In this study, we investigated the spatio-temporal dynamics of vegetation in Southeast Asia with three independent satellite derived Normalized Difference Vegetation Index (NDVI) products (GIMMS AVHRR NDVI3g, SPOT, and MODIS) as well as the recently developed Sun Induced chlorophyll Fluorescence (SIF). We furthermore examined how climate drivers (precipitation, temperature and radiation) exert influences on the vegetation dynamics. We find that the three NDVI datasets are generally consistent with each other. At seasonal scale, NDVI decreases from the beginning to the end of the dry season; at interannual scale, dry season NDVI is positively correlated to precipitation but negatively correlated to radiation, while wet season NDVI is positively correlated to radiation. Compared to evergreen forests, deciduous forests have a larger NDVI decrease rate and more extended area with positive relationships between NDVI and precipitation during the dry season. SIF is lower during dry season than during wet season. Our results indicate that most forests in Southeast Asia, unlike in the Amazonian basin, are water-limited in the dry season but radiation-limited in the wet season. These results imply that droughts may have a stronger impact on forests in Southeast Asia than in Amazon.
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Fine root dynamics along an elevational gradient in tropical Amazonian and Andean forests
NASA Astrophysics Data System (ADS)
Girardin, C. A. J.; Aragão, L. E. O. C.; Malhi, Y.; Huaraca Huasco, W.; Metcalfe, D. B.; Durand, L.; Mamani, M.; Silva-Espejo, J. E.; Whittaker, R. J.
2013-01-01
The key role of tropical forest belowground carbon stocks and fluxes is well recognised as one of the main components of the terrestrial ecosystem carbon cycle. This study presents the first detailed investigation of spatial and temporal patterns of fine root stocks and fluxes in tropical forests along an elevational gradient, ranging from the Peruvian Andes (3020 m) to lowland Amazonia (194 m), with mean annual temperatures of 11.8°C to 26.4 °C and annual rainfall values of 1900 to 1560 mm yr-1, respectively. Specifically, we analyse abiotic parameters controlling fine root dynamics, fine root growth characteristics, and seasonality of net primary productivity along the elevation gradient. Root and soil carbon stocks were measured by means of soil cores, and fine root productivity was recorded using rhizotron chambers and ingrowth cores. We find that mean annual fine root below ground net primary productivity in the montane forests (0-30 cm depth) ranged between 4.27±0.56 Mg C ha-1 yr-1 (1855 m) and 1.72±0.87 Mg C ha-1 yr-1 (3020 m). These values include a correction for finest roots (<0.6 mm diameter), which we suspect are under sampled, resulting in an underestimation of fine roots by up to 31% in current ingrowth core counting methods. We investigate the spatial and seasonal variation of fine root dynamics using soil depth profiles and an analysis of seasonal amplitude along the elevation gradient. We report a stronger seasonality of NPPFineRoot within the cloud immersion zone, most likely synchronised to seasonality of solar radiation. Finally, we provide the first insights into root growth characteristics along a tropical elevation transect: fine root area and fine root length increase significantly in the montane cloud forest. These insights into belowground carbon dynamics of tropical lowland and montane forests have significant implications for our understanding of the global tropical forest carbon cycle.
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Fire patterns in the Amazonian biome
NASA Astrophysics Data System (ADS)
Aragao, Luiz E. O. C.; Shimabukuro, Yosio E.; Lima, Andre; Anderson, Liana O.; Barbier, Nicolas; Saatchi, Sassan
2010-05-01
This paper aims to provide an overview of our recent findings on the interplay between climate and land use dynamics in defining fire patterns in Amazonia. Understanding these relationships is currently a fundamental concern for assessing the vulnerability of Amazonia to climate change and its potential for mitigating current increases in atmospheric greenhouse gases. Reducing carbon emissions from tropical deforestation and forest degradation (REDD), for instance, could contribute to a cumulative emission reduction of 13-50 billion tons of carbon (GtC) by 2100. In Amazonia, though, forest fires can release similar quantities of carbon to the atmosphere (~0.2 GtC yr-1) as deforestation alone. Therefore, to achieve carbon savings through REDD mechanism there is an urgent need of understanding and subsequently restraining related Amazonian fire drivers. In this study, we analyze satellite-derived monthly and annual time-series of fires, rainfall and deforestation in Amazonia to: (1) quantify the seasonal patterns and relationships between these variables; (2) quantify fire and rainfall anomalies to evaluate the impact of recent drought on fire patterns; (3) quantify recent trends in fire and deforestation to understand how land use affects fire patterns in Amazonia. Our results demonstrate a marked seasonality of fires. The majority of fires occurs along the Arc of Deforestation, the expanding agricultural frontier in southern and eastern Amazonia, indicating humans are the major ignition sources determining fire seasonality, spatial distribution and long-term patterns. There is a marked seasonality of fires, which is highly correlated (p<0.05) with monthly rainfall and deforestation rates. Deforestation and fires reach their highest values three and six months, respectively, after the peak of the rainy season. This result clearly describes the impact of major human activities on fire incidence, which is generally characterized by the slash-and-burn of Amazonian vegetation for implementation of pastures and agricultural fields. The cumulative number of hot pixels is exponentially related to the monthly rainfall, which ultimately defines where and when fire can potentially strike. During the 2005 Amazonian drought, the number of hot pixels increased 33% in relation to mean 1998-2005. However, even with a large fraction of the basin experiencing considerable water deficits, fires have only affect areas with extensive human activity. Our spatially explicit trend analysis on deforestation and fire data revealed that more than half of the area experiencing increased fire occurrence have reduced deforestation rates. This reverse pattern is likely to be associated with the slash-and-burn of secondary forests and the increase of fragmentation and forest edges, favouring the leakage of fires from deforested lands into forests. Finally, our analysis points towards a reduction of fire incidence due to land use intensification in this region. In this study, we demonstrated that anthropogenic forcing, such as deforestation rates, is decisive in determining the seasonality and annual patterns of fire occurrence. Moreover, droughts can significantly increase the number of fires in the region exacerbating human impacts in Amazonia. Due to ongoing deforestation and the predicted intensification of climate change induced droughts, it is anticipated that a large area of forest edge will be under increased risk of fires and carbon savings from REDD may be partially offset by increased emissions following fire events. Improved fire-free land management practices may provide a sustainable solution for reducing emissions from the world's largest rainforest. Acknowledges The first author would like to thank the financial support of the Natural Environment Research Council (NERC-UK/grant NE/F015356/1).
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Fortini, Lucas B.; Cropper, Wendell P.; Zarin, Daniel J.
2015-01-01
At the Amazon estuary, the oldest logging frontier in the Amazon, no studies have comprehensively explored the potential long-term population and yield consequences of multiple timber harvests over time. Matrix population modeling is one way to simulate long-term impacts of tree harvests, but this approach has often ignored common impacts of tree harvests including incidental damage, changes in post-harvest demography, shifts in the distribution of merchantable trees, and shifts in stand composition. We designed a matrix-based forest management model that incorporates these harvest-related impacts so resulting simulations reflect forest stand dynamics under repeated timber harvests as well as the realities of local smallholder timber management systems. Using a wide range of values for management criteria (e.g., length of cutting cycle, minimum cut diameter), we projected the long-term population dynamics and yields of hundreds of timber management regimes in the Amazon estuary, where small-scale, unmechanized logging is an important economic activity. These results were then compared to find optimal stand-level and species-specific sustainable timber management (STM) regimes using a set of timber yield and population growth indicators. Prospects for STM in Amazonian tidal floodplain forests are better than for many other tropical forests. However, generally high stock recovery rates between harvests are due to the comparatively high projected mean annualized yields from fast-growing species that effectively counterbalance the projected yield declines from other species. For Amazonian tidal floodplain forests, national management guidelines provide neither the highest yields nor the highest sustained population growth for species under management. Our research shows that management guidelines specific to a region’s ecological settings can be further refined to consider differences in species demographic responses to repeated harvests. In principle, such fine-tuned management guidelines could make management more attractive, thus bridging the currently prevalent gap between tropical timber management practice and regulation. PMID:26322896
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Fortini, Lucas B.; Cropper, Wendell P.; Zarin, Daniel J.
2015-01-01
At the Amazon estuary, the oldest logging frontier in the Amazon, no studies have comprehensively explored the potential long-term population and yield consequences of multiple timber harvests over time. Matrix population modeling is one way to simulate long-term impacts of tree harvests, but this approach has often ignored common impacts of tree harvests including incidental damage, changes in post-harvest demography, shifts in the distribution of merchantable trees, and shifts in stand composition. We designed a matrix-based forest management model that incorporates these harvest-related impacts so resulting simulations reflect forest stand dynamics under repeated timber harvests as well as the realities of local smallholder timber management systems. Using a wide range of values for management criteria (e.g., length of cutting cycle, minimum cut diameter), we projected the long-term population dynamics and yields of hundreds of timber management regimes in the Amazon estuary, where small-scale, unmechanized logging is an important economic activity. These results were then compared to find optimal stand-level and species-specific sustainable timber management (STM) regimes using a set of timber yield and population growth indicators. Prospects for STM in Amazonian tidal floodplain forests are better than for many other tropical forests. However, generally high stock recovery rates between harvests are due to the comparatively high projected mean annualized yields from fast-growing species that effectively counterbalance the projected yield declines from other species. For Amazonian tidal floodplain forests, national management guidelines provide neither the highest yields nor the highest sustained population growth for species under management. Our research shows that management guidelines specific to a region’s ecological settings can be further refined to consider differences in species demographic responses to repeated harvests. In principle, such fine-tuned management guidelines could make management more attractive, thus bridging the currently prevalent gap between tropical timber management practice and regulation.
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ERIC Educational Resources Information Center
Whitten, Norman E., Jr.
Just east of the Andes live two of the largest concentrations of tropical forest Indians in central Ecuador. Both speak Quichua which is a language long associated with Incaic expansion in the highlands and well known as a lower-class, rural, "Indian" means of communication in contemporary highland Ecuador. These Jungle Quichua live near…
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Bruna, Emilio M; de Andrade, Ana Segalin
2011-10-01
After deforestation, environmental changes in the remaining forest fragments are often most intense near the forest edge, but few studies have evaluated plant growth or plasticity of plant growth in response to edge effects. In a 2-year common garden experiment, we compared biomass allocation and growth of Heliconia acuminata with identical genotypes grown in 50 × 35 m common gardens on a 25-year-old edge and in a forest interior site. Genetically identical plants transplanted to the forest edge and understory exhibited different patterns of growth and biomass allocation. However, individuals with identical genotypes in the same garden often had very different responses. Plants on forest edges also had higher growth rates and increased biomass at the end of the experiment, almost certainly due to the increased light on the forest edge. With over 70000 km of forest edge created annually in the Brazilian Amazon, phenotypic plasticity may play an important role in mediating plant responses to these novel environmental conditions.
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NASA Astrophysics Data System (ADS)
Lean, J.; Rowntree, P. R.
1997-06-01
The experiment reported on here presents a realistic portrayal of Amazonian deforestation that uses measurements of vegetation characteristics, taken as part of the Anglo-Brazilian Amazonian Climate Observation Study field campaigns, to define the forest and replacement pasture vegetation in the Hadley Centre GCM. The duration of the main experiment (10 yr) leads to greater confidence in assessing regional changes than in previous shorter experiments.Complete removal of the Amazonian forest produced area-mean changes that resemble earlier experiments with decreases in evaporation of 0.76 mm day1 (18%) and rainfall of 0.27 mm day1 (4%) and a rise in surface temperature of 2.3°C. However, the relative changes in magnitude indicate that increased moisture convergence partly compensates for the reduced evaporation, in contrast to many previous deforestation experiments. Results also showed large regional variations in the change in annual mean rainfall over South America, with widespread decreases over most of the deforested area and increases near the Andes.A better understanding of the mechanisms responsible for the final deforested climate has been gained by carrying out additional experiments that examine the response to separate changes in roughness and albedo. Increased albedo resulted in widespread significant decreases in rainfall due to less moisture convergence and ascent. The response to reduced roughness is more complex but of comparable importance; in this experiment it was dominated by an increase in low-level wind speeds resulting in decreased moisture convergence and rainfall near the upwind edge of the area and the opposite near the downwind boundary where the increased flow meets the Andes.In the standard deforestation scenario all vegetation parameters were modified together with one soil parameter-the maximum infiltration rate, which is reduced to represent the observed compaction of soil following deforestation. Results from a further experiment, in which the maximum infiltration rate was left unchanged, showed much smaller reductions in evaporation of 0.3 mm day1 (7%) and indicated that the predicted regional changes in rainfall and evaporation were very sensitive to this parameter.
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Reduced impact logging minimally alters tropical rainforest carbon and energy exchange.
Miller, Scott D; Goulden, Michael L; Hutyra, Lucy R; Keller, Michael; Saleska, Scott R; Wofsy, Steven C; Figueira, Adelaine Michela Silva; da Rocha, Humberto R; de Camargo, Plinio B
2011-11-29
We used eddy covariance and ecological measurements to investigate the effects of reduced impact logging (RIL) on an old-growth Amazonian forest. Logging caused small decreases in gross primary production, leaf production, and latent heat flux, which were roughly proportional to canopy loss, and increases in heterotrophic respiration, tree mortality, and wood production. The net effect of RIL was transient, and treatment effects were barely discernable after only 1 y. RIL appears to provide a strategy for managing tropical forest that minimizes the potential risks to climate associated with large changes in carbon and water exchange.
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Reduced impact logging minimally alters tropical rainforest carbon and energy exchange
Miller, Scott D.; Goulden, Michael L.; Hutyra, Lucy R.; Keller, Michael; Saleska, Scott R.; Wofsy, Steven C.; Figueira, Adelaine Michela Silva; da Rocha, Humberto R.; de Camargo, Plinio B.
2011-01-01
We used eddy covariance and ecological measurements to investigate the effects of reduced impact logging (RIL) on an old-growth Amazonian forest. Logging caused small decreases in gross primary production, leaf production, and latent heat flux, which were roughly proportional to canopy loss, and increases in heterotrophic respiration, tree mortality, and wood production. The net effect of RIL was transient, and treatment effects were barely discernable after only 1 y. RIL appears to provide a strategy for managing tropical forest that minimizes the potential risks to climate associated with large changes in carbon and water exchange. PMID:22087005
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Herbivores promote habitat specialization by trees in Amazonian forests.
Fine, Paul V A; Mesones, Italo; Coley, Phyllis D
2004-07-30
In an edaphically heterogeneous area in the Peruvian Amazon, clay soils and nutrient-poor white sands each harbor distinctive plant communities. To determine whether a trade-off between growth and antiherbivore defense enforces habitat specialization on these two soil types, we conducted a reciprocal transplant study of seedlings of 20 species from six genera of phylogenetically independent pairs of edaphic specialist trees and manipulated the presence of herbivores. Clay specialist species grew significantly faster than white-sand specialists in both soil types when protected from herbivores. However, when unprotected, white-sand specialists dominated in white-sand forests and clay specialists dominated in clay forests. Therefore, habitat specialization in this system results from an interaction of herbivore pressure with soil type.
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Response of frugivorous primates to changes in fruit supply in a northern Amazonian forest.
Mourthé, I
2014-08-01
Few attempts have been made to understand how spatiotemporal changes in fruit supply influence frugivores in tropical forests. The marked spatiotemporal variation in fruit supply can affect frugivore abundance and distribution, but studies addressing the effects of this variation on primates are scarce. The present study aimed to investigate how the spatiotemporal distribution of fruits influences the local distribution of three frugivorous primates in the eastern part of the Maracá Ecological Station, a highly seasonal Amazonian rainforest. Specifically, it was hypothesised that primate distribution will track changes in fruit supply, resulting that sites with high fruit availability should be heavily used by primates. During a 1-year study, fruit supply (ground fruit surveys) and primate density (line-transects) were monitored in twelve 2 km-long transects at monthly intervals. Fruit supply varied seasonally, being low during the dry season. The density of Ateles belzebuth was positively related to fruit supply during fruit shortage, but Cebus olivaceus and Alouatta macconnelli did not follow the same pattern. The supply of Sapotaceae fruit was an important component determining local distribution of A. belzebuth during the overall fruit shortage. Highly frugivorous primates such as A. belzebuth respond to seasonal decline in fruit supply by congregating at places with high fruit supply in this forest, particularly, those with many individuals of species of Sapotaceae. This study underscores the importance of small-scale spatiotemporal changes of fruit supply as a key component of frugivorous primate ecology in highly seasonal environments.
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Peters, C M; Balick, M J; Kahn, F; Anderson, A B
1989-12-01
Tropical forests dominated by only one or two tree species occupy tens of millions of hectares in Ammonia In many cases, the dominant species produce fruits, seeds, or oils of economic importance. Oligarchic (Gr. oligo = few, archic = dominated or ruled by) forests of six economic species, i. e., Euterpe oleracea, Grias peruviana, Jessenia bataua, Mauritia flexuosa, Myrciaria dubia, and Orbignya phalerata, were studied in Brazil and Peru Natural populations of these species contain from 100 to 3,000 conspecific adult trees/ha and produce up to 11.1 metric tons of fruit/hd/yr. These plant populations are utilized and occasionally managed, by rural inhabitants in the region. Periodic fruit harvests, if properly controlled have only a minimal impact on forest structure and function, yet can generate substantial economic returns Market-oriented extraction of the fruits produced by oligarchic forests appears to represent a promising alternative for reconciling the development and conservation of Amazonian forests.
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Long-term carbon sink in Borneo's forests halted by drought and vulnerable to edge effects.
Qie, Lan; Lewis, Simon L; Sullivan, Martin J P; Lopez-Gonzalez, Gabriela; Pickavance, Georgia C; Sunderland, Terry; Ashton, Peter; Hubau, Wannes; Abu Salim, Kamariah; Aiba, Shin-Ichiro; Banin, Lindsay F; Berry, Nicholas; Brearley, Francis Q; Burslem, David F R P; Dančák, Martin; Davies, Stuart J; Fredriksson, Gabriella; Hamer, Keith C; Hédl, Radim; Kho, Lip Khoon; Kitayama, Kanehiro; Krisnawati, Haruni; Lhota, Stanislav; Malhi, Yadvinder; Maycock, Colin; Metali, Faizah; Mirmanto, Edi; Nagy, Laszlo; Nilus, Reuben; Ong, Robert; Pendry, Colin A; Poulsen, Axel Dalberg; Primack, Richard B; Rutishauser, Ervan; Samsoedin, Ismayadi; Saragih, Bernaulus; Sist, Plinio; Slik, J W Ferry; Sukri, Rahayu Sukmaria; Svátek, Martin; Tan, Sylvester; Tjoa, Aiyen; van Nieuwstadt, Mark; Vernimmen, Ronald R E; Yassir, Ishak; Kidd, Petra Susan; Fitriadi, Muhammad; Ideris, Nur Khalish Hafizhah; Serudin, Rafizah Mat; Abdullah Lim, Layla Syaznie; Saparudin, Muhammad Shahruney; Phillips, Oliver L
2017-12-19
Less than half of anthropogenic carbon dioxide emissions remain in the atmosphere. While carbon balance models imply large carbon uptake in tropical forests, direct on-the-ground observations are still lacking in Southeast Asia. Here, using long-term plot monitoring records of up to half a century, we find that intact forests in Borneo gained 0.43 Mg C ha -1 per year (95% CI 0.14-0.72, mean period 1988-2010) above-ground live biomass. These results closely match those from African and Amazonian plot networks, suggesting that the world's remaining intact tropical forests are now en masse out-of-equilibrium. Although both pan-tropical and long-term, the sink in remaining intact forests appears vulnerable to climate and land use changes. Across Borneo the 1997-1998 El Niño drought temporarily halted the carbon sink by increasing tree mortality, while fragmentation persistently offset the sink and turned many edge-affected forests into a carbon source to the atmosphere.
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NASA Astrophysics Data System (ADS)
Mitja, D.; Delaître, E.; Santos, A. M.; Miranda, I.; Coelho, R. F. R.; Macedo, D. J.; Demagistri, L.; Petit, M.
2018-02-01
When the Amazonian rain forest is cut to create pasture, some of the original vegetal species survive clearing, even expressing their ability to invade agro-systems. It is true of the babassu palm, which can be considered, paradoxically, a natural resource by the "Interstate Movement of Babassu Fruit Breaker Women" or as native weed by land owners-farmers. To manage potential conflict of land uses, we study here the current density of this palm tree in different habitats, based on a combination of field data and remote sensing data. Firstly, we checked that the field survey methodology (i.e., counting free-trunk palm trees over 20 cm in circumference) provides density values compatible with those stemming from satellite images interpretation. We can see then that, a PA-Benfica Brazilian territory revealed an average density of the babassu lower in pastures (2.86 ind/ha) than in the dense forest (4.72 ind/ha) from which they originate and than in fallow land (4.31 ind/ha). We analyze in detail density data repartition in three habitats and we discuss results from the literature on the density of this palm tree versus its resilience at different developmental stages after forest clearing, depending on anthropogenic—or not—factors, including solar radiation, fire, weeding, clear cutting, burying fruit, and competition with forage grass. All these results can be exploited for the design of future management plans for the babassu palm and we think that the linked methodology and interdisciplinary approach can be extended to others palms and trees species in similar problematic issues.
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Stevenson, Pablo R.; Link, Andrés; González-Caro, Sebastian; Torres-Jiménez, María Fernanda
2015-01-01
Frugivory is a widespread mutualistic interaction in which frugivores obtain nutritional resources while favoring plant recruitment through their seed dispersal services. Nonetheless, how these complex interactions are organized in diverse communities, such as tropical forests, is not fully understood. In this study we evaluated the existence of plant-frugivore sub-assemblages and their phylogenetic organization in an undisturbed western Amazonian forest in Colombia. We also explored for potential keystone plants, based on network analyses and an estimate of the amount of fruit going from plants to frugivores. We carried out diurnal observations on 73 canopy plant species during a period of two years. During focal tree sampling, we recorded frugivore identity, the duration of each individual visit, and feeding rates. We did not find support for the existence of sub assemblages, such as specialized vs. generalized dispersal systems. Visitation rates on the vast majority of canopy species were associated with the relative abundance of frugivores, in which ateline monkeys (i.e. Lagothrix and Ateles) played the most important roles. All fruiting plants were visited by a variety of frugivores and the phylogenetic assemblage was random in more than 67% of the cases. In cases of aggregation, the plant species were consumed by only primates or only birds, and filters were associated with fruit protection and likely chemical content. Plants suggested as keystone species based on the amount of pulp going from plants to frugivores differ from those suggested based on network approaches. Our results suggest that in tropical forests most tree-frugivore interactions are generalized, and abundance should be taken into account when assessing the most important plants for frugivores. PMID:26492037
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NASA Astrophysics Data System (ADS)
Ivanov, Valeriy Y.; Hutyra, Lucy R.; Wofsy, Steven C.; Munger, J. William; Saleska, Scott R.; de Oliveira, Raimundo C., Jr.; de Camargo, Plínio B.
2012-12-01
Large areas of Amazonian evergreen forest experience seasonal droughts extending for three or more months, yet show maximum rates of photosynthesis and evapotranspiration during dry intervals. This apparent resilience is belied by disproportionate mortality of the large trees in manipulations that reduce wet season rainfall, occurring after 2-3 years of treatment. The goal of this study is to characterize the mechanisms that produce these contrasting ecosystem responses. A mechanistic model is developed based on the ecohydrological framework of TIN (Triangulated Irregular Network)-based Real Time Integrated Basin Simulator + Vegetation Generator for Interactive Evolution (tRIBS+VEGGIE). The model is used to test the roles of deep roots and soil capillary flux to provide water to the forest during the dry season. Also examined is the importance of "root niche separation," in which roots of overstory trees extend to depth, where during the dry season they use water stored from wet season precipitation, while roots of understory trees are concentrated in shallow layers that access dry season precipitation directly. Observational data from the Tapajós National Forest, Brazil, were used as meteorological forcing and provided comprehensive observational constraints on the model. Results strongly suggest that deep roots with root niche separation adaptations explain both the observed resilience during seasonal drought and the vulnerability of canopy-dominant trees to extended deficits of wet season rainfall. These mechanisms appear to provide an adaptive strategy that enhances productivity of the largest trees in the face of their disproportionate heat loads and water demand in the dry season. A sensitivity analysis exploring how wet season rainfall affects the stability of the rainforest system is presented.
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Regional Eco-hydrologic Sensitivity to Projected Amazonian Land Use Scenarios
NASA Astrophysics Data System (ADS)
Knox, R. G.; Longo, M.; Zhang, K.; Levine, N. M.; Moorcroft, P. R.; Bras, R. L.
2011-12-01
Given business as usual land-use practices, it is estimated that by 2050 roughly half of the Amazon's pre-anthropogenic closed-canopy forest stands would remain. Of this, eight of the Amazon's twelve major hydrologic basins would lose more than half of their forest cover to deforestation. With the availability of these land-use projections, we may start to question the associated response of the region's hydrologic climate to significant land-cover change. Here the Ecosystem-Demography Model 2 (EDM2, a dynamic and spatially distributed terrestrial model of plant structure and composition, succession, disturbance and thermodynamic transfer) is coupled with the Brazilian Regional Atmospheric Model (BRAMS, a three-dimensional limited area model of the atmospheric fluid momentum equations and physics parameterizations for closing the system of equations at the lower boundary, convection, radiative transfer, microphysics, etc). This experiment conducts decadal simulations, framed with high-reliability lateral boundary conditions of reanalysis atmospheric data (ERA-40 interim) and variable impact of land-use scenarios (SimAmazonia). This is done by initializing the regional ecosystem structure with both aggressive and conservationist deforestation scenarios, and also by differentially allowing and not-allowing dynamic vegetation processes. While the lateral boundaries of the simulation will not reflect the future climate in the region, reanalysis data has provided improved realism as compared to results derived from GCM boundary data. Therefore, the ecosystem response (forest composition and structure) and the time-space patterns of hydrologic information (soil moisture, rainfall, evapotranspiration) are objectively compared in the context of a sensitivity experiment, as opposed to a forecast. The following questions are addressed. How do aggressive and conservative scenarios of Amazonian deforestation effect the regional patterning of hydrologic information in the Amazon and South American Convergence Zone, and does forest response in these regions influence that patterning of hydrologic information?
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Mitja, D; Delaître, E; Santos, A M; Miranda, I; Coelho, R F R; Macedo, D J; Demagistri, L; Petit, M
2018-02-01
When the Amazonian rain forest is cut to create pasture, some of the original vegetal species survive clearing, even expressing their ability to invade agro-systems. It is true of the babassu palm, which can be considered, paradoxically, a natural resource by the "Interstate Movement of Babassu Fruit Breaker Women" or as native weed by land owners-farmers. To manage potential conflict of land uses, we study here the current density of this palm tree in different habitats, based on a combination of field data and remote sensing data. Firstly, we checked that the field survey methodology (i.e., counting free-trunk palm trees over 20 cm in circumference) provides density values compatible with those stemming from satellite images interpretation. We can see then that, a PA-Benfica Brazilian territory revealed an average density of the babassu lower in pastures (2.86 ind/ha) than in the dense forest (4.72 ind/ha) from which they originate and than in fallow land (4.31 ind/ha). We analyze in detail density data repartition in three habitats and we discuss results from the literature on the density of this palm tree versus its resilience at different developmental stages after forest clearing, depending on anthropogenic-or not-factors, including solar radiation, fire, weeding, clear cutting, burying fruit, and competition with forage grass. All these results can be exploited for the design of future management plans for the babassu palm and we think that the linked methodology and interdisciplinary approach can be extended to others palms and trees species in similar problematic issues.
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NASA Astrophysics Data System (ADS)
Barbosa Lima, Amanda; Westphal Muniz, Aleksander; Lenhart, Katharina; Moser, Gerald; Brenzinger, Kristof; Ha, Mi-Kyung; Eckhardt, Christian; Steffens, Diedrich; Kammann, Claudia; Müller, Christoph
2017-04-01
Amazonian Dark Earth (ADE) in the Brazilian Amazon provide a strong indication that soils lacking in nutrients can be converted into highly fertile land. These soils have been considered as a model soil when compared to the surrounding soil due to the high concentrations of P, Ca, Mg, Zn, Mn, stable organic matter and soil organic C (SOC). Soils with high SOC contents can lead to extensive emissions of the greenhouse gas N2O. In this context, we measured the fluxes of CO2, N2O and CH4 in ADE and adjacent (ADJ) soils under secondary forest and manioc plantation. Moreover, we added 15N-NH4+ and -NO3- and measured N2O emissions and gross-N transformations of the different N species for two weeks (15N signal, N concentrations; work on-going), to quantify the simultaneousyl operating N transformation rates (method see: Müller et al. (2004; 2007). We observed higher amounts of NO3- in both ADE and ADJ soils under forest. High consumption rates for NH4+ were shown by both ADE soils under forest followed by manioc plantation. CO2 effluxes from ADJ were higher than from ADE soils, and higher from the forest compared to the manioc plantation. N2O fluxes were much lower in ADE under forest and higher in the other soils. The results of the gross N transformations are distinctively different among ADE and Adjacent sites, providing a strong indication how the dynamics of the individual N transformation rates have been affected by the long-term management. References cited Müller et al. (2004) A 15N tracing model to analyse N-transformations in old grassland soil. SBB 36:619-632. Müller et al. (2007) Estimation of parameters in complex 15N tracing models by Monte Carlo sampling. SBB 39:715-726.
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Amazon Forest maintenance as a source of environmental services.
Fearnside, Philip M
2008-03-01
Amazonian forest produces environmental services such as maintenance of biodiversity, water cycling and carbon stocks. These services have a much greater value to human society than do the timber, beef and other products that are obtained by destroying the forest. Yet institutional mechanisms are still lacking to transform the value of the standing forest into the foundation of an economy based on maintaining rather than destroying this ecosystem. Forest management for commodities such as timber and non-timber forest products faces severe limitations and inherent contradictions unless income is supplemented based on environmental services. Amazon forest is threatened by deforestation, logging, forest fires and climate change. Measures to avoid deforestation include repression through command and control, creation of protected areas, and reformulation of infrastructure decisions and development policies. An economy primarily based on the value of environmental services is essential for long-term maintenance of the forest. Much progress has been made in the decades since I first proposed such a transition, but many issues also remain unresolved. These include theoretical issues regarding accounting procedures, improved quantification of the services and of the benefits of different policy options, and effective uses of the funds generated in ways that maintain both the forest and the human population.
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Nitrous oxide flux and nitrogen transformations across a landscape gradient in Amazonia
NASA Technical Reports Server (NTRS)
Livingston, Gerald P.; Vitousek, Peter M.; Matson, Pamela A.
1988-01-01
Nitrous oxide flux and nitrogen turnover were measured in three types of Amazonian forest ecosystems within Reserva Florestal Ducke near Manaus, Brazil. Nitrogen mineralization and nitrate production measured during 10-day laboratory incubations were 3-4 times higher in clay soils associated with 'terra firme' forests on ridge-top and slope positions than in 'campinarana' forests on bottomland sand soils. In contrast, nitrous oxide fluxes did not differ significantly among sites, but were highly variable in space and time. The observed frequency distribution of flux was positively skewed, with a mean overall sites and all sampling times of 1.3 ng N2O-N/sq cm per hr. Overall, the flux estimates were comparable to or greater than those of temperature forests, but less than others reported for Amazoonia. Results from a field fertilization experiment suggest that most nitrous oxide flux was associated with denitrification of soil nitrate.
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Sparse pre-Columbian human habitation in western Amazonia.
McMichael, C H; Piperno, D R; Bush, M B; Silman, M R; Zimmerman, A R; Raczka, M F; Lobato, L C
2012-06-15
Locally extensive pre-Columbian human occupation and modification occurred in the forests of the central and eastern Amazon Basin, but whether comparable impacts extend westward and into the vast terra firme (interfluvial) zones, remains unclear. We analyzed soils from 55 sites across central and western Amazonia to assess the history of human occupation. Sparse occurrences of charcoal and the lack of phytoliths from agricultural and disturbance species in the soils during pre-Columbian times indicated that human impacts on interfluvial forests were small, infrequent, and highly localized. No human artifacts or modified soils were found at any site surveyed. Riverine bluff areas also appeared less heavily occupied and disturbed than similar settings elsewhere. Our data indicate that human impacts on Amazonian forests were heterogeneous across this vast landscape.
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C-13/C-12 of atmospheric CO2 in the Amazon basin - Forest and river sources
NASA Technical Reports Server (NTRS)
Quay, Paul; King, Stagg; Wilbur, Dave; Richey, Jeffrey; Wofsy, Steven
1989-01-01
Results are presented of measurements of the CO2 concentrations and C-13/C-12 ratios in CO2 in air samples collected from within the Amazonian rain forest and over the Amazon river between 1982 and 1987. Results indicate the presence of a diurnal cycle in the CO2 concentration and the C-13/C-12 ratio. It was found that the CO2 input to air in the forest was derived from the soil respiration, and the CO2 input to air over the Amazon river was derived from the degassing of CO2 from the river. It was also found that plants growing at heights lower than 7 m assimilate soil-derived CO2 with a low C-13/C-12 ratio.
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A Hydrogeomorphic Classification for Wetlands
1993-08-01
Research Program (WRP). The work was performed under Work Unit 32756, for which Mr. R. Daniel Smith was Principal Investigator . Mr. John Bellinger...34Laws of temperature control of the geographic distribution of terrestrial animals and plants," National Geographic Magazine 6, 229-238. Metzler, K. J...34Notes on the vegetation of Amazonia . III. The terminology of Amazonian forest types subject to inundation," Brittonia 31, 26-38. Prince, H. H., and
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The distribution and amount of carbon in the largest peatland complex in Amazonia
NASA Astrophysics Data System (ADS)
Draper, Frederick C.; Roucoux, Katherine H.; Lawson, Ian T.; Mitchard, Edward T. A.; Honorio Coronado, Euridice N.; Lähteenoja, Outi; Torres Montenegro, Luis; Valderrama Sandoval, Elvis; Zaráte, Ricardo; Baker, Timothy R.
2014-12-01
Peatlands in Amazonian Peru are known to store large quantities of carbon, but there is high uncertainty in the spatial extent and total carbon stocks of these ecosystems. Here, we use a multi-sensor (Landsat, ALOS PALSAR and SRTM) remote sensing approach, together with field data including 24 forest census plots and 218 peat thickness measurements, to map the distribution of peatland vegetation types and calculate the combined above- and below-ground carbon stock of peatland ecosystems in the Pastaza-Marañon foreland basin in Peru. We find that peatlands cover 35 600 ± 2133 km2 and contain 3.14 (0.44-8.15) Pg C. Variation in peat thickness and bulk density are the most important sources of uncertainty in these values. One particular ecosystem type, peatland pole forest, is found to be the most carbon-dense ecosystem yet identified in Amazonia (1391 ± 710 Mg C ha-1). The novel approach of combining optical and radar remote sensing with above- and below-ground carbon inventories is recommended for developing regional carbon estimates for tropical peatlands globally. Finally, we suggest that Amazonian peatlands should be a priority for research and conservation before the developing regional infrastructure causes an acceleration in the exploitation and degradation of these ecosystems.
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Alvarez, Nora L; Naughton-Treves, Lisa
2003-06-01
Amazonian deforestation rates vary regionally, and ebb and flow according to macroeconomic policy and local social factors. We used remote sensing and field interviews to investigate deforestation patterns and drivers at a Peruvian frontier during 1986-1991, when rural credit and guaranteed markets were available; and 1991-1997, when structural adjustment measures were imposed. The highest rate of clearing (1.5% gross) was observed along roads during 1986-1991. Roadside deforestation slowed in 1991-1997 (0.7% gross) and extensive regrowth yielded a net increase in forest cover (0.5%). Deforestation along rivers was relatively constant. Riverside farms today retain more land in both crops and forest than do roadside farms where pasture and successional growth predominate. Long-term residents maintain more forest on their farms than do recent colonists, but proximity to urban markets is the strongest predictor of forest cover. Future credit programs must reflect spatial patterns of development and ecological vulnerability, and support the recuperation of fallow lands and secondary forest.
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Amazonian phylogeography: mtDNA sequence variation in arboreal echimyid rodents (Caviomorpha).
da Silva, M N; Patton, J L
1993-09-01
Patterns of evolutionary relationships among haplotype clades of sequences of the mitochondrial cytochrome b DNA gene are examined for five genera of arboreal rodents of the Caviomorph family Echimyidae from the Amazon Basin. Data are available for 798 bp of sequence from a total of 24 separate localities in Peru, Venezuela, Bolivia, and Brazil for Mesomys, Isothrix, Makalata, Dactylomys, and Echimys. Sequence divergence, corrected for multiple hits, is extensive, ranging from less than 1% for comparisons within populations of over 20% among geographic units within genera. Both the degree of differentiation and the geographic patterning of the variation suggest that more than one species composes the Amazonian distribution of the currently recognized Mesomys hispidus, Isothrix bistriata, Makalata didelphoides, and Dactylomys dactylinus. There is general concordance in the geographic range of haplotype clades for each of these taxa, and the overall level of differentiation within them is largely equivalent. These observations suggest that a common vicariant history underlies the respective diversification of each genus. However, estimated times of divergence based on the rate of third position transversion substitutions for the major clades within each genus typically range above 1 million years. Thus, allopatric isolation precipitating divergence must have been considerably earlier than the late Pleistocene forest fragmentation events commonly invoked for Amazonian biota.
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Spatial trends in leaf size of Amazonian rainforest trees
NASA Astrophysics Data System (ADS)
Malhado, A. C. M.; Malhi, Y.; Whittaker, R. J.; Ladle, R. J.; Ter Steege, H.; Aragão, L. E. O. C.; Quesada, C. A.; Araujo-Murakami, A.; Phillips, O. L.; Peacock, J.; Lopez-Gonzalez, G.; Baker, T. R.; Butt, N.; Anderson, L. O.; Arroyo, L.; Almeida, S.; Higuchi, N.; Killeen, T. J.; Monteagudo, A.; Neill, D.; Pitman, N.; Prieto, A.; Salomão, R. P.; Silva, N.; Vásquez-Martínez, R.; Laurance, W. F.
2009-02-01
Leaf size influences many aspects of tree function such as rates of transpiration and photosynthesis and, consequently, often varies in a predictable way in response to environmental gradients. The recent development of pan-Amazonian databases based on permanent botanical plots (e.g. RAINFOR, ATDN) has now made it possible to assess trends in leaf size across environmental gradients in Amazonia. Previous plot-based studies have shown that the community structure of Amazonian trees breaks down into at least two major ecological gradients corresponding with variations in soil fertility (decreasing south to northeast) and length of the dry season (increasing from northwest to south and east). Here we describe the results of the geographic distribution of leaf size categories based on 121 plots distributed across eight South American countries. We find that, as predicted, the Amazon forest is predominantly populated by tree species and individuals in the mesophyll size class (20.25-182.25 cm2). The geographic distribution of species and individuals with large leaves (>20.25 cm2) is complex but is generally characterized by a higher proportion of such trees in the north-west of the region. Spatially corrected regressions reveal weak correlations between the proportion of large-leaved species and metrics of water availability. We also find a significant negative relationship between leaf size and wood density.
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Spatial trends in leaf size of Amazonian rainforest trees
NASA Astrophysics Data System (ADS)
Malhado, A. C. M.; Malhi, Y.; Whittaker, R. J.; Ladle, R. J.; Ter Steege, H.; Phillips, O. L.; Butt, N.; Aragão, L. E. O. C.; Quesada, C. A.; Araujo-Murakami, A.; Arroyo, L.; Peacock, J.; Lopez-Gonzalez, G.; Baker, T. R.; Anderson, L. O.; Almeida, S.; Higuchi, N.; Killeen, T. J.; Monteagudo, A.; Neill, D.; Pitman, N.; Prieto, A.; Salomão, R. P.; Vásquez-Martínez, R.; Laurance, W. F.
2009-08-01
Leaf size influences many aspects of tree function such as rates of transpiration and photosynthesis and, consequently, often varies in a predictable way in response to environmental gradients. The recent development of pan-Amazonian databases based on permanent botanical plots has now made it possible to assess trends in leaf size across environmental gradients in Amazonia. Previous plot-based studies have shown that the community structure of Amazonian trees breaks down into at least two major ecological gradients corresponding with variations in soil fertility (decreasing from southwest to northeast) and length of the dry season (increasing from northwest to south and east). Here we describe the geographic distribution of leaf size categories based on 121 plots distributed across eight South American countries. We find that the Amazon forest is predominantly populated by tree species and individuals in the mesophyll size class (20.25-182.25 cm2). The geographic distribution of species and individuals with large leaves (>20.25 cm2) is complex but is generally characterized by a higher proportion of such trees in the northwest of the region. Spatially corrected regressions reveal weak correlations between the proportion of large-leaved species and metrics of water availability. We also find a significant negative relationship between leaf size and wood density.
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Ohashi, Shinta; Durgante, Flávia M; Kagawa, Akira; Kajimoto, Takuya; Trumbore, Susan E; Xu, Xiaomei; Ishizuka, Moriyoshi; Higuchi, Niro
2016-03-01
In Amazonian non-flooded forests with a moderate dry season, many trees do not form anatomically definite annual rings. Alternative indicators of annual rings, such as the oxygen (δ(18)Owc) and carbon stable isotope ratios of wood cellulose (δ(13)Cwc), have been proposed; however, their applicability in Amazonian forests remains unclear. We examined seasonal variations in the δ(18)Owc and δ(13)Cwc of three common species (Eschweilera coriacea, Iryanthera coriacea, and Protium hebetatum) in Manaus, Brazil (Central Amazon). E. coriacea was also sampled in two other regions to determine the synchronicity of the isotopic signals among different regions. The annual cyclicity of δ(18)Owc variation was cross-checked by (14)C dating. The δ(18)Owc showed distinct seasonal variations that matched the amplitude observed in the δ(18)O of precipitation, whereas seasonal δ(13)Cwc variations were less distinct in most cases. The δ(18)Owc variation patterns were similar within and between some individual trees in Manaus. However, the δ(18)Owc patterns of E. coriacea differed by region. The ages of some samples estimated from the δ(18)Owc cycles were offset from the ages estimated by (14)C dating. In the case of E. coriacea, this phenomenon suggested that missing or wedging rings may occur frequently even in well-grown individuals. Successful cross-dating may be facilitated by establishing δ(18)Owc master chronologies at both seasonal and inter-annual scales for tree species with distinct annual rings in each region.
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Seasonal genetic partitioning in the neotropical malaria vector, Anopheles darlingi
2014-01-01
Background Anopheles darlingi is the main malaria mosquito vector in the Amazonia region. In spite of being considered a riverine, forest-dwelling species, this mosquito is becoming more abundant in peri-urban areas, increasing malaria risk. This has been associated with human-driven environmental changes such as deforestation. Methods Microsatellites were used to characterize A. darlingi from seven localities along the Madeira River, Rondônia (Brazil), collected in the early and late periods of the rainy season. Results Two genetically distinct subpopulations were detected: one (subpopulation A) was associated with the late rainfall period and seems to be ecologically closer to the typical forest A. darlingi; the other (subpopulation B) was associated with the early rainfall period and is probably more adapted to drier conditions by exploiting permanent anthropogenic breeding sites. Results suggest also a pattern of asymmetric introgression, with more subpopulation A alleles introgressed into subpopulation B. Both subpopulations (and admixed mosquitoes) presented similar malaria infection rates, highlighting the potential for perennial malaria transmission in the region. Conclusions The co-occurrence of two genetically distinct subpopulations of A. darlingi adapted to different periods of rainfall may promote a more perennial transmission of malaria throughout the year. These findings, in a context of strong environmental impact due to deforestation and dam construction, have serious implications for malaria epidemiology and control in the Amazonian region. PMID:24885508
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Large-scale degradation of Amazonian freshwater ecosystems
NASA Astrophysics Data System (ADS)
Castello, L.; Macedo, M.
2016-12-01
The integrity of freshwater ecosystems depends on their hydrological connectivity with land, water, and climate systems. Hydrological connectivity regulates the structure and function of Amazonian freshwater ecosystems and the provisioning of services that sustain local populations. However, the hydrological connectivity of Amazonian freshwater ecosystems is increasingly disrupted by construction of dams, mining, land-cover changes, and global climate change. This review analyzes these drivers of degradation; evaluates their impacts on hydrological connectivity; and identifies policy deficiencies that hinder freshwater ecosystem protection. There are 155 large hydroelectric dams in operation, 21 dams under construction, and there will be only three free-flowing tributaries if all 277 planned dams for the Basin are built. Land-cover changes driven by mining, dam and road construction, and agriculture and cattle ranching have already affected 20% of the Basin and up to 50% of riparian forests in some regions. Global climate change will likely exacerbate these impacts by creating warmer and dryer conditions, with less predictable rainfall and more extreme events (e.g. droughts and floods). The resulting hydrological alterations are rapidly degrading freshwater ecosystems both independently and via complex feedbacks and synergistic interactions. The ecosystem impacts include biodiversity loss, warmer stream temperatures, stronger and more frequent floodplain fires, and changes to biogeochemical cycles, transport of organic and inorganic materials, and freshwater community structure and function. The impacts also include reductions in water quality, fish yields, and availability of water for navigation, power generation, and human use. This degradation of Amazonian freshwater ecosystems cannot be curbed presently because existing policies are inconsistent across the Basin, ignore cumulative effects, and do not consider the hydrological connectivity of freshwater ecosystems. Maintaining the integrity of these freshwater ecosystems requires a basin-wide research and policy framework to understand and manage hydrological connectivity across multiple spatial scales and jurisdictional boundaries.
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Application of a linear spectral model to the study of Amazonian squall lines during GTE/ABLE 2B
NASA Technical Reports Server (NTRS)
Silva Dias, Maria A. F.; Ferreira, Rosana N.
1992-01-01
A linear nonhydrostatic spectral model is run with the basic state, or large scale, vertical profiles of temperature and wind observed prior to convective development along the northern coast of South America during the GTE/ABLE 2B. The model produces unstable modes with mesoscale wavelength and propagation speed comparable to observed Amazonian squall lines. Several tests with different vertical profiles of low-level winds lead to the conclusion that a shallow and/or weak low-level jet either does not produce a scale selection or, if it does, the selected mode is stationary, indicating the absence of a propagating disturbance. A 700-mbar jet of 13 m/s, with a 600-mbar wind speed greater or equal to 10 m/s, is enough to produce unstable modes with propagating features resembling those of observed Amazonian squall lines. However, a deep layer of moderate winds (about 10 m/s) may produce similar results even in the absence of a low-level wind maximum. The implications in terms of short-term weather forecasting are discussed.
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Who is Amazonia? The ‘salt of the matter’ for indigenous sustainability
NASA Astrophysics Data System (ADS)
Heckenberger, Michael
2013-12-01
The recent article ‘Ash salts and bodily affects: Witoto environmental knowledge as sexual education’ (Echeverri and Román-Jitdutjaãno 2013 Environ. Res. Lett. 8 015008) considers indigenous people and their distinctive knowledge systems in the western Amazon. These complex systems provide richly detailed practical knowledge about life in these tropical forests, which today many see as well populated and rich in cultural heritage. Through a careful analysis of ash salts and salt-making and the technologies and bodily affects associated with it, the authors suggest native Amazonian peoples see environmental knowledge not in terms of natural resources but instead how they interact with and produce human bodies in social networks, as a form of sexual education and, by extension, public health. It also highlights the critical importance of social relations as part of research, and the politics of nature, with important implications for contemporary debate and research on biodiversity, sustainability, climate change and human rights, specifically what types of agreements are entailed in scientific research that is not only robust but socially responsible.
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Rockwell, Cara A.; Guariguata, Manuel R.; Menton, Mary; Arroyo Quispe, Eriks; Quaedvlieg, Julia; Warren-Thomas, Eleanor; Fernandez Silva, Harol; Jurado Rojas, Edwin Eduardo; Kohagura Arrunátegui, José Andrés Hideki; Meza Vega, Luis Alberto; Revilla Vera, Olivia; Valera Tito, Jonatan Frank; Villarroel Panduro, Betxy Tabita; Yucra Salas, Juan José
2015-01-01
Although many examples of multiple-use forest management may be found in tropical smallholder systems, few studies provide empirical support for the integration of selective timber harvesting with non-timber forest product (NTFP) extraction. Brazil nut (Bertholletia excelsa, Lecythidaceae) is one of the world’s most economically-important NTFP species extracted almost entirely from natural forests across the Amazon Basin. An obligate out-crosser, Brazil nut flowers are pollinated by large-bodied bees, a process resulting in a hard round fruit that takes up to 14 months to mature. As many smallholders turn to the financial security provided by timber, Brazil nut fruits are increasingly being harvested in logged forests. We tested the influence of tree and stand-level covariates (distance to nearest cut stump and local logging intensity) on total nut production at the individual tree level in five recently logged Brazil nut concessions covering about 4000 ha of forest in Madre de Dios, Peru. Our field team accompanied Brazil nut harvesters during the traditional harvest period (January-April 2012 and January-April 2013) in order to collect data on fruit production. Three hundred and ninety-nine (approximately 80%) of the 499 trees included in this study were at least 100 m from the nearest cut stump, suggesting that concessionaires avoid logging near adult Brazil nut trees. Yet even for those trees on the edge of logging gaps, distance to nearest cut stump and local logging intensity did not have a statistically significant influence on Brazil nut production at the applied logging intensities (typically 1–2 timber trees removed per ha). In one concession where at least 4 trees ha-1 were removed, however, the logging intensity covariate resulted in a marginally significant (0.09) P value, highlighting a potential risk for a drop in nut production at higher intensities. While we do not suggest that logging activities should be completely avoided in Brazil nut rich forests, when a buffer zone cannot be observed, low logging intensities should be implemented. The sustainability of this integrated management system will ultimately depend on a complex series of socioeconomic and ecological interactions. Yet we submit that our study provides an important initial step in understanding the compatibility of timber harvesting with a high value NTFP, potentially allowing for diversification of forest use strategies in Amazonian Perù. PMID:26271042
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Rockwell, Cara A; Guariguata, Manuel R; Menton, Mary; Arroyo Quispe, Eriks; Quaedvlieg, Julia; Warren-Thomas, Eleanor; Fernandez Silva, Harol; Jurado Rojas, Edwin Eduardo; Kohagura Arrunátegui, José Andrés Hideki; Meza Vega, Luis Alberto; Revilla Vera, Olivia; Quenta Hancco, Roger; Valera Tito, Jonatan Frank; Villarroel Panduro, Betxy Tabita; Yucra Salas, Juan José
2015-01-01
Although many examples of multiple-use forest management may be found in tropical smallholder systems, few studies provide empirical support for the integration of selective timber harvesting with non-timber forest product (NTFP) extraction. Brazil nut (Bertholletia excelsa, Lecythidaceae) is one of the world's most economically-important NTFP species extracted almost entirely from natural forests across the Amazon Basin. An obligate out-crosser, Brazil nut flowers are pollinated by large-bodied bees, a process resulting in a hard round fruit that takes up to 14 months to mature. As many smallholders turn to the financial security provided by timber, Brazil nut fruits are increasingly being harvested in logged forests. We tested the influence of tree and stand-level covariates (distance to nearest cut stump and local logging intensity) on total nut production at the individual tree level in five recently logged Brazil nut concessions covering about 4000 ha of forest in Madre de Dios, Peru. Our field team accompanied Brazil nut harvesters during the traditional harvest period (January-April 2012 and January-April 2013) in order to collect data on fruit production. Three hundred and ninety-nine (approximately 80%) of the 499 trees included in this study were at least 100 m from the nearest cut stump, suggesting that concessionaires avoid logging near adult Brazil nut trees. Yet even for those trees on the edge of logging gaps, distance to nearest cut stump and local logging intensity did not have a statistically significant influence on Brazil nut production at the applied logging intensities (typically 1-2 timber trees removed per ha). In one concession where at least 4 trees ha-1 were removed, however, the logging intensity covariate resulted in a marginally significant (0.09) P value, highlighting a potential risk for a drop in nut production at higher intensities. While we do not suggest that logging activities should be completely avoided in Brazil nut rich forests, when a buffer zone cannot be observed, low logging intensities should be implemented. The sustainability of this integrated management system will ultimately depend on a complex series of socioeconomic and ecological interactions. Yet we submit that our study provides an important initial step in understanding the compatibility of timber harvesting with a high value NTFP, potentially allowing for diversification of forest use strategies in Amazonian Perù.
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Floodplains as an Achilles’ heel of Amazonian forest resilience
Flores, Bernardo M.; Holmgren, Milena; van Nes, Egbert H.; Jakovac, Catarina C.; Mesquita, Rita C. G.; Scheffer, Marten
2017-01-01
The massive forests of central Amazonia are often considered relatively resilient against climatic variation, but this view is challenged by the wildfires invoked by recent droughts. The impact of such fires that spread from pervasive sources of ignition may reveal where forests are less likely to persist in a drier future. Here we combine field observations with remotely sensed information for the whole Amazon to show that the annually inundated lowland forests that run through the heart of the system may be trapped relatively easily into a fire-dominated savanna state. This lower forest resilience on floodplains is suggested by patterns of tree cover distribution across the basin, and supported by our field and remote sensing studies showing that floodplain fires have a stronger and longer-lasting impact on forest structure as well as soil fertility. Although floodplains cover only 14% of the Amazon basin, their fires can have substantial cascading effects because forests and peatlands may release large amounts of carbon, and wildfires can spread to adjacent uplands. Floodplains are thus an Achilles’ heel of the Amazon system when it comes to the risk of large-scale climate-driven transitions. PMID:28396440
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Lees, Alexander C; Peres, Carlos A
2008-04-01
Forest corridors are often considered the main instrument with which to offset the effects of habitat loss and fragmentation. Brazilian forestry legislation requires that all riparian zones on private landholdings be maintained as permanent reserves and sets fixed minimum widths of riparian forest buffers to be retained alongside rivers and perennial streams. We investigated the effects of corridor width and degradation status of 37 riparian forest sites (including 24 corridors connected to large source-forest patches, 8 unconnected forest corridors, and 5 control riparian zones embedded within continuous forest patches) on bird and mammal species richness in a hyper-fragmented forest landscape surrounding Alta Floresta, Mato Grosso, Brazil. We used point-count and track-sampling methodology, coupled with an intensive forest-quality assessment that combined satellite imagery and ground truthed data. Vertebrate use of corridors was highly species-specific, but broad trends emerged depending on species life histories and their sensitivity to disturbance. Narrow and/or highly disturbed riparian corridors retained only a depauperate vertebrate assemblage that was typical of deforested habitats, whereas wide, well-preserved corridors retained a nearly complete species assemblage. Restriction of livestock movement along riparian buffers and their exclusion from key areas alongside deforested streams would permit corridor regeneration and facilitate restoration of connectivity.
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REDD and PINC: A new policy framework to fund tropical forests as global 'eco-utilities'
NASA Astrophysics Data System (ADS)
Trivedi, M. R.; Mitchell, A. W.; Mardas, N.; Parker, C.; Watson, J. E.; Nobre, A. D.
2009-11-01
Tropical forests are 'eco-utilities' providing critical ecosystem services that underpin food, energy, water and climate security at local to global scales. Currently, these services are unrecognised and unrewarded in international policy and financial frameworks, causing forests to be worth more dead than alive. Much attention is currently focused on REDD (Reducing Emissions from Deforestation and forest Degradation) and A/R (Afforestation and Reforestation) as mitigation options. In this article we propose an additional mechanism - PINC (Proactive Investment in Natural Capital) - that recognises and rewards the value of ecosystem services provided by standing tropical forests, especially from a climate change adaptation perspective. Using Amazonian forests as a case study we show that PINC could improve the wellbeing of rural and forest-dependent populations, enabling them to cope with the impacts associated with climate change and deforestation. By investing pro-actively in areas where deforestation pressures are currently low, the long-term costs of mitigation and adaptation will be reduced. We suggest a number of ways in which funds could be raised through emerging financial mechanisms to provide positive incentives to maintain standing forests. To develop PINC, a new research and capacity-building agenda is needed that explores the interdependence between communities, the forest eco-utility and the wider economy.
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Effects of dam-induced landscape fragmentation on amazonian ant-plant mutualistic networks.
Emer, Carine; Venticinque, Eduardo Martins; Fonseca, Carlos Roberto
2013-08-01
Mutualistic networks are critical to biological diversity maintenance; however, their structures and functionality may be threatened by a swiftly changing world. In the Amazon, the increasing number of dams poses a large threat to biological diversity because they greatly alter and fragment the surrounding landscape. Tight coevolutionary interactions typical of tropical forests, such as the ant-myrmecophyte mutualism, where the myrmecophyte plants provide domatia nesting space to their symbiotic ants, may be jeopardized by the landscape changes caused by dams. We analyzed 31 ant-myrmecophyte mutualistic networks in undisturbed and disturbed sites surrounding Balbina, the largest Central Amazonian dam. We tested how ant-myrmecophyte networks differ among dam-induced islands, lake edges, and undisturbed forests in terms of species richness, composition, structure, and robustness (number of species remaining in the network after partner extinctions). We also tested how landscape configuration in terms of area, isolation, shape, and neighborhood alters the structure of the ant-myrmecophyte networks on islands. Ant-myrmecophytic networks were highly compartmentalized in undisturbed forests, and the compartments had few strongly connected mutualistic partners. In contrast, networks at lake edges and on islands were not compartmentalized and were negatively affected by island area and isolation in terms of species richness, density, and composition. Habitat loss and fragmentation led to coextinction cascades that contributed to the elimination of entire ant-plant compartments. Furthermore, many myrmecophytic plants in disturbed sites lost their mutualistic ant partners or were colonized by opportunistic, nonspecialized ants. Robustness of ant-myrmecophyte networks on islands was lower than robustness near lake edges and in undisturbed forest and was particularly susceptible to the extinction of plants. Beyond the immediate habitat loss caused by the building of large dams in Amazonia, persistent edge effects and habitat fragmentation associated with dams had large negative effects on animal-plant mutualistic networks. © 2013 Society for Conservation Biology.
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Moser, Gerald; Schuldt, Bernhard; Hertel, Dietrich; Horna, Viviana; Coners, Heinz; Barus, Henry; Leuschner, Christoph
2014-05-01
Climate change scenarios predict increases in the frequency and duration of ENSO-related droughts for parts of South-East Asia until the end of this century exposing the remaining rainforests to increasing drought risk. A pan-tropical review of recorded drought-related tree mortalities in more than 100 monitoring plots before, during and after drought events suggested a higher drought-vulnerability of trees in South-East Asian than in Amazonian forests. Here, we present the results of a replicated (n = 3 plots) throughfall exclusion experiment in a perhumid tropical rainforest in Sulawesi, Indonesia. In this first large-scale roof experiment outside semihumid eastern Amazonia, 60% of the throughfall was displaced during the first 8 months and 80% during the subsequent 17 months, exposing the forest to severe soil desiccation for about 17 months. In the experiment's second year, wood production decreased on average by 40% with largely different responses of the tree families (ranging from -100 to +100% change). Most sensitive were trees with high radial growth rates under moist conditions. In contrast, tree height was only a secondary factor and wood specific gravity had no influence on growth sensitivity. Fine root biomass was reduced by 35% after 25 months of soil desiccation while fine root necromass increased by 250% indicating elevated fine root mortality. Cumulative aboveground litter production was not significantly reduced in this period. The trees from this Indonesian perhumid rainforest revealed similar responses of wood and litter production and root dynamics as those in two semihumid Amazonian forests subjected to experimental drought. We conclude that trees from paleo- or neotropical forests growing in semihumid or perhumid climates may not differ systematically in their growth sensitivity and vitality under sublethal drought stress. Drought vulnerability may depend more on stem cambial activity in moist periods than on tree height or wood specific gravity. © 2013 John Wiley & Sons Ltd.
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NASA Technical Reports Server (NTRS)
Nepstad, Daniel; Stone, Thomas; Davidson, Eric; Trumbore, Susan E.
1992-01-01
The main objective of these NASA-funded projects is to improve our understanding of land-use impacts on soil carbon dynamics in the Amazon Basin. Soil contains approximately one half of tropical forest carbon stocks, yet the fate of this carbon following forest impoverishment is poorly studied. Our mechanistics approach draws on numerous techniques for measuring soil carbon outputs, inputs, and turnover time in the soils of adjacent forest and pasture ecosystems at our research site in Paragominas, state of Para, Brazil. We are scaling up from this site-specific work by analyzing Basin-wide patterns in rooting depth and rainfall seasonality, the two factors that we believe should explain much of the variation in tropical soil carbons dynamics. In this report, we summarize ongoing measurements at our Paragominas study site, progress in employing new field data to understand soil C dynamics, and some surprising results from our regional, scale-up work.
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A free-access online key to identify Amazonian ferns.
Zuquim, Gabriela; Tuomisto, Hanna; Prado, Jefferson
2017-01-01
There is urgent need for more data on species distributions in order to improve conservation planning. A crucial but challenging aspect of producing high-quality data is the correct identification of organisms. Traditional printed floras and dichotomous keys are difficult to use for someone not familiar with the technical jargon. In poorly known areas, such as Amazonia, they also become quickly outdated as new species are described or ranges extended. Recently, online tools have allowed developing dynamic, interactive, and accessible keys that make species identification possible for a broader public. In order to facilitate identifying plants collected in field inventories, we developed an internet-based free-access tool to identify Amazonian fern species. We focused on ferns, because they are easy to collect and their edaphic affinities are relatively well known, so they can be used as an indicator group for habitat mapping. Our key includes 302 terrestrial and aquatic entities mainly from lowland Amazonian forests. It is a free-access key, so the user can freely choose which morphological features to use and in which order to assess them. All taxa are richly illustrated, so specimens can be identified by a combination of character choices, visual comparison, and written descriptions. The identification tool was developed in Lucid 3.5 software and it is available at http://keyserver.lucidcentral.org:8080/sandbox/keys.jsp.
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A free-access online key to identify Amazonian ferns
Zuquim, Gabriela; Tuomisto, Hanna; Prado, Jefferson
2017-01-01
Abstract There is urgent need for more data on species distributions in order to improve conservation planning. A crucial but challenging aspect of producing high-quality data is the correct identification of organisms. Traditional printed floras and dichotomous keys are difficult to use for someone not familiar with the technical jargon. In poorly known areas, such as Amazonia, they also become quickly outdated as new species are described or ranges extended. Recently, online tools have allowed developing dynamic, interactive, and accessible keys that make species identification possible for a broader public. In order to facilitate identifying plants collected in field inventories, we developed an internet-based free-access tool to identify Amazonian fern species. We focused on ferns, because they are easy to collect and their edaphic affinities are relatively well known, so they can be used as an indicator group for habitat mapping. Our key includes 302 terrestrial and aquatic entities mainly from lowland Amazonian forests. It is a free-access key, so the user can freely choose which morphological features to use and in which order to assess them. All taxa are richly illustrated, so specimens can be identified by a combination of character choices, visual comparison, and written descriptions. The identification tool was developed in Lucid 3.5 software and it is available at http://keyserver.lucidcentral.org:8080/sandbox/keys.jsp. PMID:28781548
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Thermal physiology of Amazonian lizards (Reptilia: Squamata)
Caetano, Gabriel H. O.; Pontes, Emerson; Ávila-Pires, Teresa C. S.
2018-01-01
We summarize thermal-biology data of 69 species of Amazonian lizards, including mode of thermoregulation and field-active body temperatures (Tb). We also provide new data on preferred temperatures (Tpref), voluntary and thermal-tolerance ranges, and thermal-performance curves (TPC’s) for 27 species from nine sites in the Brazilian Amazonia. We tested for phylogenetic signal and pairwise correlations among thermal traits. We found that species generally categorized as thermoregulators have the highest mean values for all thermal traits, and broader ranges for Tb, critical thermal maximum (CTmax) and optimal (Topt) temperatures. Species generally categorized as thermoconformers have large ranges for Tpref, critical thermal minimum (CTmin), and minimum voluntary (VTmin) temperatures for performance. Despite these differences, our results show that all thermal characteristics overlap between both groups and suggest that Amazonian lizards do not fit into discrete thermoregulatory categories. The traits are all correlated, with the exceptions of (1) Topt, which does not correlate with CTmax, and (2) CTmin, and correlates only with Topt. Weak phylogenetic signals for Tb, Tpref and VTmin indicate that these characters may be shaped by local environmental conditions and influenced by phylogeny. We found that open-habitat species perform well under present environmental conditions, without experiencing detectable thermal stress from high environmental temperatures induced in lab experiments. For forest-dwelling lizards, we expect warming trends in Amazonia to induce thermal stress, as temperatures surpass the thermal tolerances for these species. PMID:29513695
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Environmental characteristics drive variation in Amazonian understorey bird assemblages
Magnusson, William E.; Anderson, Marti J.; Schlegel, Martin; Pe’er, Guy; Henle, Klaus
2017-01-01
Tropical bird assemblages display patterns of high alpha and beta diversity and, as tropical birds exhibit strong habitat specificity, their spatial distributions are generally assumed to be driven primarily by environmental heterogeneity and interspecific interactions. However, spatial distributions of some Amazonian forest birds are also often restricted by large rivers and other large-scale topographic features, suggesting that dispersal limitation may also play a role in driving species’ turnover. In this study, we evaluated the effects of environmental characteristics, topographic and spatial variables on variation in local assemblage structure and diversity of birds in an old-growth forest in central Amazonia. Birds were mist-netted in 72 plots distributed systematically across a 10,000 ha reserve in each of three years. Alpha diversity remained stable through time, but species composition changed. Spatial variation in bird-assemblage structure was significantly related to environmental and topographic variables but not strongly related to spatial variables. At a broad scale, we found bird assemblages to be significantly distinct between two watersheds that are divided by a central ridgeline. We did not detect an effect of the ridgeline per se in driving these patterns, indicating that most birds are able to fly across it, and that differences in assemblage structure between watersheds may be due to unmeasured environmental variables or unique combinations of measured variables. Our study indicates that complex geography and landscape features can act together with environmental variables to drive changes in the diversity and composition of tropical bird assemblages at local scales, but highlights that we still know very little about what makes different parts of tropical forest suitable for different species. PMID:28225774
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Sandoval, José Raul; Madsen, Hans O.; De Stefano, Gianfranco; Descailleaux-Dulanto, Jaime; Velazquez-Reinoso, Margarita; Ñique, Cesar; Fujita, Ricardo; Garred, Peter
2014-01-01
Mannose-binding lectin (MBL) is one of the five recognition molecules in the lectin complement pathway. Common variant alleles in the promoter and structural regions of the human MBL gene (MBL2) influence the stability and serum concentration of the protein. Epidemiological studies have shown that MBL2 variant alleles are associated with susceptibility to and the course of different types of infectious and inflammatory conditions. However, it has been suggested that these alleles are maintained in different populations due to selected advantages for carriers. We investigated the MBL2 allelic variation in indigenous individuals from 12 different West Central South America localities spanning from the desert coast, high altitude Andean plates and the Amazon tropical forest within the territories of Peru (n = 249) (Departments of Loreto, Ucayali, Lambayeque, Junin, Ayacucho, Huancayo and Puno), and Ecuador (n = 182) (Region of Esmeraldas and Santo Domingo de los Colorados). The distribution of MBL2 genotypes among the populations showed that the defective variant LYPB haplotype was very common. It showed the highest frequencies in Puno (Taquile (0.80), Amantani (0.80) and Anapia (0.58) islander communities of the Lake Titicaca), but lower frequencies of 0.22 in Junin (Central Andean highland) and Ucayali (Central Amazonian forest), as well as 0.27 and 0.24 in the Congoma and Cayapa/Chachis populations in the Amazonian forest in Ecuador were also observed. Our results suggest that the high prevalence of the MBL2 LYPB variant causing low levels of functional MBL in serum may mainly reflect a random distribution due to a population bottleneck in the founder populations. PMID:25313559
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NASA Astrophysics Data System (ADS)
Shi, Mingjie; Liu, Junjie; Zhao, Maosheng; Yu, Yifan; Saatchi, Sassan
2017-12-01
The long-term impact of Amazonian drought on canopy structure has been observed in ground and remote sensing measurements. However, it is still unclear whether it is caused by biotic (e.g., plant structure damage) or environmental (e.g., water deficiency) factors. We used the Community Land Model version 4.5 (CLM4.5) and radar backscatter observations from SeaWinds Scatterometer on board QuikSCAT (QSCAT) satellite to investigate the relative role of biotic and environmental factors in controlling the forest canopy disturbance and recovery processes after the 2005 Amazonian drought. We validated the CLM4.5 simulation of the drought impact and the recovery of leaf carbon (C) pool, an indicator of canopy structure, over southwestern Amazonia with QSCAT backscatter observations, which are sensitive to canopy structure change. We found that the leaf C pool simulated by CLM4.5 recovered to the 2000-2009 mean level (343 g C m-2) in 3 years after a sharp decrease in 2005, consistent with the QSCAT observed slow recovery. Through sensitivity experiments, we found that the slow C recovery was primarily due to biotic factors represented by the canopy damage and reduction of plant C pools. The recovery of soil water and the coupling between water and C pools, which is an environmental factor, only contributes 24% to the leaf C recovery. The results showed (1) the strength of scatterometer backscatter measurements in capturing canopy damage over tropical forests and in validating C cycle models and (2) the biotic factors play the dominant role in regulating the drought induced disturbance and persistent canopy changes in CLM4.5.
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Long term atmospheric aerosol characterization in the Amazon Basin
NASA Astrophysics Data System (ADS)
Artaxo, Paulo; Gerab, Fábio; Yamasoe, Marcia A.
This chapter presents a characterization of atmospheric aerosols collected in different places in the Amazon Basin. Both the biogenic aerosol emission from the forest and the particulate material which is emitted to the atmosphere due to the large scale man-made burns during the dry season were studied. The samples were collected during a three year period at three different locations in the Amazon (Cuiabá, Alta Floresta and Serra do Navio), using stacked filter units. Aerosol samples were also collected directly over fires of cerrado vegetation and tropical primary forest burns The samples were analyzed using several techniques for a number of elements. Gravimetric analyses were used to determine the total atmospheric aerosol concentration. Multivariate statistical analysis was used in order to identify and characterize the sources of the atmospheric aerosol present in the sampled regions. Cerrado burning emissions were enriched compared to forest ones, specially for Cl, K and Zn. High atmospheric aerosol concentrations were observed in large amazonian areas due to emissions from man-made burns in the period from June to September. The emissions from burns dominate the fine fraction of the atmospheric aerosol with characteristic high contents of black carbon, S and K. Aerosols emitted in biomass burning process are correlated to the increase in the aerosol optical thickness of the atmosphere during the Amazonian dry season. The Serra do Navio aerosol is characterized by biogenic emissions with strong marine influence. The presence of trace elements characteristic of soil particulate associated with this marine contribution indicates the existence of aerosol transport from Africa to South America. Similar composition characteristics were observed in the biogenic emission aerosols from Serra do Navio and Alta Floresta.
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Drivers of metacommunity structure diverge for common and rare Amazonian tree species.
Bispo, Polyanna da Conceição; Balzter, Heiko; Malhi, Yadvinder; Slik, J W Ferry; Dos Santos, João Roberto; Rennó, Camilo Daleles; Espírito-Santo, Fernando D; Aragão, Luiz E O C; Ximenes, Arimatéa C; Bispo, Pitágoras da Conceição
2017-01-01
We analysed the flora of 46 forest inventory plots (25 m x 100 m) in old growth forests from the Amazonian region to identify the role of environmental (topographic) and spatial variables (obtained using PCNM, Principal Coordinates of Neighbourhood Matrix analysis) for common and rare species. For the analyses, we used multiple partial regression to partition the specific effects of the topographic and spatial variables on the univariate data (standardised richness, total abundance and total biomass) and partial RDA (Redundancy Analysis) to partition these effects on composition (multivariate data) based on incidence, abundance and biomass. The different attributes (richness, abundance, biomass and composition based on incidence, abundance and biomass) used to study this metacommunity responded differently to environmental and spatial processes. Considering standardised richness, total abundance (univariate) and composition based on biomass, the results for common species differed from those obtained for all species. On the other hand, for total biomass (univariate) and for compositions based on incidence and abundance, there was a correspondence between the data obtained for the total community and for common species. Our data also show that in general, environmental and/or spatial components are important to explain the variability in tree communities for total and common species. However, with the exception of the total abundance, the environmental and spatial variables measured were insufficient to explain the attributes of the communities of rare species. These results indicate that predicting the attributes of rare tree species communities based on environmental and spatial variables is a substantial challenge. As the spatial component was relevant for several community attributes, our results demonstrate the importance of using a metacommunities approach when attempting to understand the main ecological processes underlying the diversity of tropical forest communities.
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Leaf phenology as one important driver of seasonal changes in isoprene emission in central Amazonia
Alves, Eliane G.; Tota, Julio; Turnipseed, Andrew; ...
2018-03-06
Isoprene fluxes vary seasonally with changes in environmental factors (e.g., solar radiation and temperature) and biological factors (e.g., leaf phenology). However, our understanding of seasonal patterns of isoprene fluxes and associated mechanistic controls are still limited, especially in Amazonian evergreen forests. Here in this article, we aim to connect intensive, field-based measurements of canopy isoprene flux over a central Amazonian evergreen forest with meteorological observations and with tower-camera leaf phenology to improve understanding of patterns and causes of isoprene flux seasonality. Our results demonstrate that the highest isoprene emissions are observed during the dry and dry-to-wet transition seasons, whereas themore » lowest emissions were found during the wet-to-dry transition season. Our results also indicate that light and temperature can not totally explain the isoprene flux seasonality. Instead, the camera-derived leaf area index (LAI) of recently mature leaf-age class (e.g. leaf ages of 3–5 months) exhibits the highest correlation with observed isoprene flux seasonality (R 2=0.59, p<0.05). Attempting to better represent leaf phenology in the Model of Emissions of Gases and Aerosols from Nature (MEGAN 2.1), we improved the leaf age algorithm utilizing results from the camera-derived leaf phenology that provided LAI categorized in three different leaf ages. The model results show that the observations of age-dependent isoprene emission capacity, in conjunction with camera-derived leaf age demography, significantly improved simulations in terms of seasonal variations of isoprene fluxes (R 2=0.52, p<0.05). This study highlights the importance of accounting for differences in isoprene emission capacity across canopy leaf age classes and of identifying forest adaptive mechanisms that underlie seasonal variation of isoprene emissions in Amazonia.« less
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Leaf phenology as one important driver of seasonal changes in isoprene emission in central Amazonia
DOE Office of Scientific and Technical Information (OSTI.GOV)
Alves, Eliane G.; Tota, Julio; Turnipseed, Andrew
Isoprene fluxes vary seasonally with changes in environmental factors (e.g., solar radiation and temperature) and biological factors (e.g., leaf phenology). However, our understanding of seasonal patterns of isoprene fluxes and associated mechanistic controls are still limited, especially in Amazonian evergreen forests. Here in this article, we aim to connect intensive, field-based measurements of canopy isoprene flux over a central Amazonian evergreen forest with meteorological observations and with tower-camera leaf phenology to improve understanding of patterns and causes of isoprene flux seasonality. Our results demonstrate that the highest isoprene emissions are observed during the dry and dry-to-wet transition seasons, whereas themore » lowest emissions were found during the wet-to-dry transition season. Our results also indicate that light and temperature can not totally explain the isoprene flux seasonality. Instead, the camera-derived leaf area index (LAI) of recently mature leaf-age class (e.g. leaf ages of 3–5 months) exhibits the highest correlation with observed isoprene flux seasonality (R 2=0.59, p<0.05). Attempting to better represent leaf phenology in the Model of Emissions of Gases and Aerosols from Nature (MEGAN 2.1), we improved the leaf age algorithm utilizing results from the camera-derived leaf phenology that provided LAI categorized in three different leaf ages. The model results show that the observations of age-dependent isoprene emission capacity, in conjunction with camera-derived leaf age demography, significantly improved simulations in terms of seasonal variations of isoprene fluxes (R 2=0.52, p<0.05). This study highlights the importance of accounting for differences in isoprene emission capacity across canopy leaf age classes and of identifying forest adaptive mechanisms that underlie seasonal variation of isoprene emissions in Amazonia.« less
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Sandoval, José Raul; Madsen, Hans O; De Stefano, Gianfranco; Descailleaux-Dulanto, Jaime; Velazquez-Reinoso, Margarita; Ñique, Cesar; Fujita, Ricardo; Garred, Peter
2014-01-01
Mannose-binding lectin (MBL) is one of the five recognition molecules in the lectin complement pathway. Common variant alleles in the promoter and structural regions of the human MBL gene (MBL2) influence the stability and serum concentration of the protein. Epidemiological studies have shown that MBL2 variant alleles are associated with susceptibility to and the course of different types of infectious and inflammatory conditions. However, it has been suggested that these alleles are maintained in different populations due to selected advantages for carriers. We investigated the MBL2 allelic variation in indigenous individuals from 12 different West Central South America localities spanning from the desert coast, high altitude Andean plates and the Amazon tropical forest within the territories of Peru (n = 249) (Departments of Loreto, Ucayali, Lambayeque, Junin, Ayacucho, Huancayo and Puno), and Ecuador (n = 182) (Region of Esmeraldas and Santo Domingo de los Colorados). The distribution of MBL2 genotypes among the populations showed that the defective variant LYPB haplotype was very common. It showed the highest frequencies in Puno (Taquile (0.80), Amantani (0.80) and Anapia (0.58) islander communities of the Lake Titicaca), but lower frequencies of 0.22 in Junin (Central Andean highland) and Ucayali (Central Amazonian forest), as well as 0.27 and 0.24 in the Congoma and Cayapa/Chachis populations in the Amazonian forest in Ecuador were also observed. Our results suggest that the high prevalence of the MBL2 LYPB variant causing low levels of functional MBL in serum may mainly reflect a random distribution due to a population bottleneck in the founder populations.
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Rain forest fragmentation and the proliferation of successional trees.
Laurance, William F; Nascimento, Henrique E M; Laurance, Susan G; Andrade, Ana C; Fearnside, Philip M; Ribeiro, José E L; Capretz, Robson L
2006-02-01
The effects of habitat fragmentation on diverse tropical tree communities are poorly understood. Over a 20-year period we monitored the density of 52 tree species in nine predominantly successional genera (Annona, Bellucia, Cecropia, Croton, Goupia, Jacaranda, Miconia, Pourouma, Vismia) in fragmented and continuous Amazonian forests. We also evaluated the relative importance of soil, topographic, forest dynamic, and landscape variables in explaining the abundance and species composition of successional trees. Data were collected within 66 permanent 1-ha plots within a large (approximately 1000 km2) experimental landscape, with forest fragments ranging from 1 to 100 ha in area. Prior to forest fragmentation, successional trees were uncommon, typically comprising 2-3% of all trees (> or =10 cm diameter at breast height [1.3 m above the ground surface]) in each plot. Following fragmentation, the density and basal area of successional trees increased rapidly. By 13-17 years after fragmentation, successional trees had tripled in abundance in fragment and edge plots and constituted more than a quarter of all trees in some plots. Fragment age had strong, positive effects on the density and basal area of successional trees, with no indication of a plateau in these variables, suggesting that successional species could become even more abundant in fragments over time. Nonetheless, the 52 species differed greatly in their responses to fragmentation and forest edges. Some disturbance-favoring pioneers (e.g., Cecropia sciadophylla, Vismia guianensis, V. amazonica, V. bemerguii, Miconia cf. crassinervia) increased by >1000% in density on edge plots, whereas over a third (19 of 52) of all species remained constant or declined in numbers. Species responses to fragmentation were effectively predicted by their median growth rate in nearby intact forest, suggesting that faster-growing species have a strong advantage in forest fragments. An ordination analysis revealed three main gradients in successional-species composition across our study area. Species gradients were most strongly influenced by the standlevel rate of tree mortality on each plot and by the number of nearby forest edges. Species-composition also varied significantly among different cattle ranches, which differed in their surrounding matrices and disturbance histories. These same variables were also the best predictors of total successional-tree abundance and species richness. Successional-tree assemblages in fragment interior plots (>150 m from edge), which are subjected to fragment area effects but not edge effects, did not differ significantly from those in intact forest, indicating that area effects per se had little influence on successional trees. Soils and topography also had little discernable effect on these species. Collectively, our results indicate that successional-tree species proliferate rapidly in fragmented Amazonian forests, largely as a result of chronically elevated tree mortality near forest edges and possibly an increased seed rain from successional plants growing in nearby degraded habitats. The proliferation of fast-growing successional trees and correlated decline of old-growth trees will have important effects on species composition, forest dynamics, carbon storage, and nutrient cycling in fragmented forests.
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Stronger seasonal adjustment in leaf turgor loss point in lianas than trees in an Amazonian forest.
Maréchaux, Isabelle; Bartlett, Megan K; Iribar, Amaia; Sack, Lawren; Chave, Jérôme
2017-01-01
Pan-tropically, liana density increases with decreasing rainfall and increasing seasonality. This pattern has led to the hypothesis that lianas display a growth advantage over trees under dry conditions. However, the physiological mechanisms underpinning this hypothesis remain elusive. A key trait influencing leaf and plant drought tolerance is the leaf water potential at turgor loss point (π tlp ). π tlp adjusts under drier conditions and this contributes to improved leaf drought tolerance. For co-occurring Amazonian tree (n = 247) and liana (n = 57) individuals measured during the dry and the wet seasons, lianas showed a stronger osmotic adjustment than trees. Liana leaves were less drought-tolerant than trees in the wet season, but reached similar drought tolerances during the dry season. Stronger osmotic adjustment in lianas would contribute to turgor maintenance, a critical prerequisite for carbon uptake and growth, and to the success of lianas relative to trees in growth under drier conditions. © 2017 The Author(s).
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Parolin, Pia
2009-01-01
Background In Amazonian floodplain forests, >1000 tree species grow in an environment subject to extended annual submergence which can last up to 9 months each year. Water depth can reach 10 m, fully submerging young and also adult trees, most of which reproduce during the flood season. Complete submergence occurs regularly at the seedling or sapling stage for many species that colonize low-lying positions in the flooding gradient. Here hypoxic conditions prevail close to the water surface in moving water, while anaerobic conditions are common in stagnant pools. Light intensities in the floodwater are very low. Questions and Aims Despite a lack of both oxygen and light imposed by submergence for several months, most leafed seedlings survive. Furthermore, underwater growth has also been observed in several species in the field and under experimental conditions. The present article assesses how these remarkable plants react to submergence and discusses physiological mechanisms and anatomical adaptations that may explain their success. PMID:19001429
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Mapping Process to Pattern in the Landscape Change of the Amazonian Frontier
NASA Technical Reports Server (NTRS)
Walker, Robert
2003-01-01
Changes in land use and land cover are dynamic processes reflecting a sequence of decisions made by individual land managers. In developing economies, these decisions may be embedded in the evolution of individual households, as is often the case in indigenous areas and agricultural frontiers. One goal of the present article is to address the land use and land-cover decisions of colonist farmers in the Amazon Basin as a function, in part, of household characteristics. Another goal is to generalize the issue of tropical deforestation into a broader discussion on forest dynamics. The extent of secondary forest in tropical areas has been well documented in South America and Africa. Agricultural-plot abandonment often occurs in tandem with primary forest clearance and as part of the same decision-making calculus. Consequently, tropical deforestation and forest succession are not independent processes in the landscape. This article presents a framework that integrates them into a model of forest dynamics at household level, and in so doing provides an account of the spatial pattern of deforestation that has been observed in the Amazon's colonization frontiers.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Fang, Yilin; Leung, L. Ruby; Duan, Zhuoran
The Amazon basin experienced periodic droughts in the past, and climate models projected more intense and frequent droughts in the future. How tropical forests respond to drought may depend on water availability, which is modulated by landscape heterogeneity. Using the one-dimensional ACME Land Model (ALM) and the three-dimensional ParFlow variably saturated flow model, a series of numerical experiments were performed for the Asu catchment in central Amazon to elucidate processes that influence water available for plant use and provide insights for improving Earth system models. Results from ParFlow show that topography has a dominant influence on groundwater table and runoffmore » through lateral flow. Without any representations of lateral processes, ALM simulates very different seasonal variations in groundwater table and runoff compared to ParFlow even if it is able to reproduce the long-term spatial average groundwater table of ParFlow through simple parameter calibration. In the ParFlow simulations, the groundwater table is evidently deeper and the soil saturation is lower in the plateau compared to the valley. However, even in the plateau during the dry season in the drought year of 2005, plant transpiration is not water stressed in the ParFlow simulations as the soil saturation is still sufficient to maintain a soil matric potential for the stomata to be fully open. This finding is insensitive to uncertainty in atmospheric forcing and soil parameters, but the empirical wilting formulation used in the models is an important factor that should be addressed using observations and modeling of coupled plant hydraulics-soil hydrology processes in future studies.« less
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The Impact of Amazonian Deforestation on Dry-Season Rainfall
NASA Technical Reports Server (NTRS)
Negri, Andrew J.; Adler, Robert F.; Xu, Li-Ming; Surratt, Jason; Starr, David OC. (Technical Monitor)
2002-01-01
Many modeling studies have concluded that widespread deforestation of Amazonia would lead to decreased rainfall. We analyze geosynchronous infrared satellite data with respect percent cloudiness, and analyze rain estimates from microwave sensors aboard the Tropical Rainfall Measuring Mission satellite. We conclude that in the dry-season, when the effects of the surface are not overwhelmed by synoptic-scale weather disturbances, deep convective cloudiness, as well as rainfall occurrence, all increase over the deforested and non-forested (savanna) regions. This is in response to a local circulation initiated by the differential heating of the region's varying forestation. Analysis of the diurnal cycle of cloudiness reveals a shift toward afternoon hours in the deforested and savanna regions, compared to the forested regions. Analysis of 14 years of data from the Special Sensor Microwave/Imager data revealed that only in August did rainfall amounts increase over the deforested region.
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Dispersal limitation induces long-term biomass collapse in overhunted Amazonian forests.
Peres, Carlos A; Emilio, Thaise; Schietti, Juliana; Desmoulière, Sylvain J M; Levi, Taal
2016-01-26
Tropical forests are the global cornerstone of biological diversity, and store 55% of the forest carbon stock globally, yet sustained provisioning of these forest ecosystem services may be threatened by hunting-induced extinctions of plant-animal mutualisms that maintain long-term forest dynamics. Large-bodied Atelinae primates and tapirs in particular offer nonredundant seed-dispersal services for many large-seeded Neotropical tree species, which on average have higher wood density than smaller-seeded and wind-dispersed trees. We used field data and models to project the spatial impact of hunting on large primates by ∼ 1 million rural households throughout the Brazilian Amazon. We then used a unique baseline dataset on 2,345 1-ha tree plots arrayed across the Brazilian Amazon to model changes in aboveground forest biomass under different scenarios of hunting-induced large-bodied frugivore extirpation. We project that defaunation of the most harvest-sensitive species will lead to losses in aboveground biomass of between 2.5-5.8% on average, with some losses as high as 26.5-37.8%. These findings highlight an urgent need to manage the sustainability of game hunting in both protected and unprotected tropical forests, and place full biodiversity integrity, including populations of large frugivorous vertebrates, firmly in the agenda of reducing emissions from deforestation and forest degradation (REDD+) programs.
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Ecology: 'Devil's gardens' bedevilled by ants.
Frederickson, Megan E; Greene, Michael J; Gordon, Deborah M
2005-09-22
'Devil's gardens' are large stands of trees in the Amazonian rainforest that consist almost entirely of a single species, Duroia hirsuta, and, according to local legend, are cultivated by an evil forest spirit. Here we show that the ant Myrmelachista schumanni, which nests in D. hirsuta stems, creates devil's gardens by poisoning all plants except its host plants with formic acid. By killing these other plants, M. schumanni provides its colonies with abundant nest sites--a long-lasting benefit as colonies can live for 800 years.
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Impact of a drier Early-Mid-Holocene climate upon Amazonian forests.
Mayle, Francis E; Power, Mitchell J
2008-05-27
This paper uses a palaeoecological approach to examine the impact of drier climatic conditions of the Early-Mid-Holocene (ca 8000-4000 years ago) upon Amazonia's forests and their fire regimes. Palaeovegetation (pollen data) and palaeofire (charcoal) records are synthesized from 20 sites within the present tropical forest biome, and the underlying causes of any emergent patterns or changes are explored by reference to independent palaeoclimate data and present-day patterns of precipitation, forest cover and fire activity across Amazonia. During the Early-Mid-Holocene, Andean cloud forest taxa were replaced by lowland tree taxa as the cloud base rose while lowland ecotonal areas, which are presently covered by evergreen rainforest, were instead dominated by savannahs and/or semi-deciduous dry forests. Elsewhere in the Amazon Basin there is considerable spatial and temporal variation in patterns of vegetation disturbance and fire, which probably reflects the complex heterogeneous patterns in precipitation and seasonality across the basin, and the interactions between climate change, drought- and fire susceptibility of the forests, and Palaeo-Indian land use. Our analysis shows that the forest biome in most parts of Amazonia appears to have been remarkably resilient to climatic conditions significantly drier than those of today, despite widespread evidence of forest burning. Only in ecotonal areas is there evidence of biome replacement in the Holocene. From this palaeoecological perspective, we argue against the Amazon forest 'dieback' scenario simulated for the future.
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Implications of plant acclimation for future climate-carbon cycle feedbacks
NASA Astrophysics Data System (ADS)
Mercado, Lina; Kattge, Jens; Cox, Peter; Sitch, Stephen; Knorr, Wolfgang; Lloyd, Jon; Huntingford, Chris
2010-05-01
The response of land ecosystems to climate change and associated feedbacks are a key uncertainty in future climate prediction (Friedlingstein et al. 2006). However global models generally do not account for the acclimation of plant physiological processes to increased temperatures. Here we conduct a first global sensitivity study whereby we modify the Joint UK land Environment Simulator (JULES) to account for temperature acclimation of two main photosynthetic parameters, Vcmax and Jmax (Kattge and Knorr 2007) and plant respiration (Atkin and Tjoelker 2003). The model is then applied over the 21st Century within the IMOGEN framework (Huntingford et al. 2004). Model simulations will provide new and improved projections of biogeochemical cycling, forest resilience, and thus more accurate projections of climate-carbon cycle feedbacks and the future evolution of the Earth System. Friedlingstein P, Cox PM, Betts R et al. (2006) Climate-carbon cycle feedback analysis, results from the C4MIP model intercomparison. Journal of Climate, 19, 3337-3353. Kattge J and Knorr W (2007): Temperature acclimation in a biochemical model of photosynthesis: a reanalysis of data from 36 species. Plant, Cell and Environment 30, 1176-1190 Atkin O.K and Tjoelker, M. G. (2003): Thermal acclimation and the dynamic response of plant respiration to temperature. Trends in Plant Science 8 (7), 343-351 Huntingford C, et al. (2004) Using a GCM analogue model to investigate the potential for Amazonian forest dieback. Theoretical and Applied Climatology, 78, 177-185.
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de Oliveira, Rodrigo Leonardo Costa; Farias, Hugo Leonardo Sousa; Perdiz, Ricardo de Oliveira; Scudeller, Veridiana Vizoni; Imbrozio Barbosa, Reinaldo
2017-01-01
Woody plant diversity from the Amazonian savannas has been poorly quantified. In order to improve the knowledge on wood plants of these regional ecosystems, a tree inventory was carried out in four different habitats used by indigenous people living in the savanna areas of the Northern Brazilian Amazon. The habitats were divided into two types (or groups) of vegetation formations: forest (riparian forest, forest island, and buritizal = Mauritia palm formation) and non-forest (typical savanna). The inventory was carried out in two hectares established in the Darora Indigenous Community region, north of the state of Roraima. The typical savanna is the most densely populated area (709 stems ha -1 ); however, it has the lowest tree species richness (nine species, seven families) in relation to typical forest habitats: riparian forest (22 species, 13 families and 202 stems ha -1 ), forest islands (13 species, 10 families and 264 stems ha -1 ), and buritizal (19 species, 15 families and 600 stems ha -1 ). The tree structure (density and dominance) of the forest habitats located in the savanna areas studied in this work is smaller in relation to forest habitats derived from continuous areas of other parts of the Amazon. These environments are derived from Paleoclimatic fragmentation, and are currently affected by the impact of intensive use of natural resources as timberselective logging and some land conversion for agriculture.
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Cloutier, D; Kanashiro, M; Ciampi, A Y; Schoen, D J
2007-02-01
Selective logging may impact patterns of genetic diversity within populations of harvested forest tree species by increasing distances separating conspecific trees, and modifying physical and biotic features of the forest habitat. We measured levels of gene diversity, inbreeding, pollen dispersal and spatial genetic structure (SGS) of an Amazonian insect-pollinated Carapa guianensis population before and after commercial selective logging. Similar levels of gene diversity and allelic richness were found before and after logging in both the adult and the seed generations. Pre- and post-harvest outcrossing rates were high, and not significantly different from one another. We found no significant levels of biparental inbreeding either before or after logging. Low levels of pollen pool differentiation were found, and the pre- vs. post-harvest difference was not significant. Pollen dispersal distance estimates averaged between 75 m and 265 m before logging, and between 76 m and 268 m after logging, depending on the value of tree density and the dispersal model used. There were weak and similar levels of differentiation of allele frequencies in the adults and in the pollen pool, before and after logging occurred, as well as weak and similar pre- and post-harvest levels of SGS among adult trees. The large neighbourhood sizes estimated suggest high historical levels of gene flow. Overall our results indicate that there is no clear short-term genetic impact of selective logging on this population of C. guianensis.
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Ground-Vegetation Clutter Affects Phyllostomid Bat Assemblage Structure in Lowland Amazonian Forest.
Marciente, Rodrigo; Bobrowiec, Paulo Estefano D; Magnusson, William E
2015-01-01
Vegetation clutter is a limiting factor for bats that forage near ground level, and may determine the distribution of species and guilds. However, many studies that evaluated the effects of vegetation clutter on bats have used qualitative descriptions rather than direct measurements of vegetation density. Moreover, few studies have evaluated the effect of vegetation clutter on a regional scale. Here, we evaluate the influence of the physical obstruction of vegetation on phyllostomid-bat assemblages along a 520 km transect in continuous Amazonian forest. We sampled bats using mist nets in eight localities during 80 nights (3840 net-hours) and estimated the ground-vegetation density with digital photographs. The total number of species, number of animalivorous species, total number of frugivorous species, number of understory frugivorous species, and abundance of canopy frugivorous bats were negatively associated with vegetation clutter. The bat assemblages showed a nested structure in relation to degree of clutter, with animalivorous and understory frugivorous bats distributed throughout the vegetation-clutter gradient, while canopy frugivores were restricted to sites with more open vegetation. The species distribution along the gradient of vegetation clutter was not closely associated with wing morphology, but aspect ratio and wing load differed between frugivores and animalivores. Vegetation structure plays an important role in structuring assemblages of the bats at the regional scale by increasing beta diversity between sites. Differences in foraging strategy and diet of the guilds seem to have contributed more to the spatial distribution of bats than the wing characteristics of the species alone.
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Hubbell, Stephen P; He, Fangliang; Condit, Richard; Borda-de-Agua, Luís; Kellner, James; Ter Steege, Hans
2008-08-12
New roads, agricultural projects, logging, and mining are claiming an ever greater area of once-pristine Amazonian forest. The Millennium Ecosystems Assessment (MA) forecasts the extinction of a large fraction of Amazonian tree species based on projected loss of forest cover over the next several decades. How accurate are these estimates of extinction rates? We use neutral theory to estimate the number, relative abundance, and range size of tree species in the Amazon metacommunity and estimate likely tree-species extinctions under published optimistic and nonoptimistic Amazon scenarios. We estimate that the Brazilian portion of the Amazon Basin has (or had) 11,210 tree species that reach sizes >10 cm DBH (stem diameter at breast height). Of these, 3,248 species have population sizes >1 million individuals, and, ignoring possible climate-change effects, almost all of these common species persist under both optimistic and nonoptimistic scenarios. At the rare end of the abundance spectrum, however, neutral theory predicts the existence of approximately 5,308 species with <10,000 individuals each that are expected to suffer nearly a 50% extinction rate under the nonoptimistic deforestation scenario and an approximately 37% loss rate even under the optimistic scenario. Most of these species have small range sizes and are highly vulnerable to local habitat loss. In ensembles of 100 stochastic simulations, we found mean total extinction rates of 20% and 33% of tree species in the Brazilian Amazon under the optimistic and nonoptimistic scenarios, respectively.
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The expansion of intensive agriculture and ranching in Brazilian Amazonia
NASA Astrophysics Data System (ADS)
Walker, Robert; DeFries, Ruth; del Carmen Vera-Diaz, Maria; Shimabukuro, Yosio; Venturieri, Adriano
Agriculture in Amazonia has often provoked controversy, given the tremendous ecological value of the region's environment. First with ranching, and now with the soybean boom, tractors and cattle have marched across lands that for millennia supported only closed moist forest, resident ecosystems, and dispersed indigenous peoples. The present chapter considers this expansion, focusing on the Brazilian portion of the basin. Its premise is that effective Amazonian policy must be grounded on an understanding of the region's agriculture. The chapter pursues its objectives by first addressing the development initiatives that created the preconditions for Amazonia's current agricultural economy. The region is remote and has therefore required sustained government intervention to release its potential. The policy discussion is followed by descriptions of cattle ranching and soy farming. For each, market settings and trajectories of expansion are presented. Although these sectoral descriptions are data rich, they do not provide a conceptual framework for analyzing the environmental impacts of evolving market conditions. To accomplish this, the chapter invokes the classical land use model of von Thünen to explain Amazonian land cover dynamics in relation to soy-cattle linkages. It addresses these dynamics with remote sensing data from Mato Grosso, Pará, and Rondônia, and then discusses scenarios of agricultural advances on the forest. Conclusions follow, considering possible policy responses to deforestation, and the social context of agricultural intensification, with special attention to the issues of land tenure security and distributional equity.
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Tropical small streams are a consistent source of methane
NASA Astrophysics Data System (ADS)
Vihermaa, Leena; Waldron, Susan
2013-04-01
To date only a few studies have quantified diffusive methane emissions from headwater streams therefore the magnitude and seasonal variation of these emissions remain poorly understood. Here we present results from two Western Amazonian small streams (first and second order) in Tambopata National Reserve, Peru. Towards the end of wet season, April-May 2012, the streams were sampled using a static floating chamber to accumulate methane. Samples were drawn from the headspace twice daily over period of four days on three separate occasions. The methane concentrations were analysed using a gas chromatograph and the linear part of concentration increase used to calculate the flux rates. The streams were consistently outgassing methane. The seasonally active first order stream outgassed 6 ±2.4 nmol CH4-C m-2 s-1 and the second order stream 20 ±4.0 nmol CH4-C m-2 s-1. The latter flux rate is comparable to fluxes measured from seasonally flooded Amazonian forest in previous studies. The range measured in our streams is comparable to previous results in temperate streams and the lower end of fluxes observed in some peatland streams. The only other study on Amazonian small streams detected methane fluxes that were 100 times greater than those measured here. Depending on the density of small streams in Amazonian basin and the prevalent flux rate, the fluvial methane fluxes may constitute a significant global warming potential. Upscaling to the Amazon basin, assuming small stream density of 0.2 %, as was found at our field site, and the flux rates detected, yields an annual global warming potential equal to approximately 1.5 Mt of CO2 which is of minor importance compared to aquatic CO2-C flux of 500 Mt yr-1 from the basin. However, if the higher fluxes detected in the previous study were prevalent, the basin wide methane flux could become significant. Further studies are needed to establish the stream density in the Amazon basin and typical methane flux rates.
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Contrasting colonist and indigenous impacts on amazonian forests.
Lu, Flora; Gray, Clark; Bilsborrow, Richard E; Mena, Carlos F; Erlien, Christine M; Bremner, Jason; Barbieri, Alisson; Walsh, Stephen J
2010-06-01
To examine differences in land use and environmental impacts between colonist and indigenous populations in the northern Ecuadorian Amazon, we combined data from household surveys and remotely sensed imagery that was collected from 778 colonist households in 64 colonization sectors, and 499 households from five indigenous groups in 36 communities. Overall, measures of deforestation and forest fragmentation were significantly greater for colonists than indigenous peoples. On average, colonist households had approximately double the area in agriculture and cash crops and 5.5 times the area in pasture as indigenous households. Nevertheless, substantial variation in land-use patterns existed among the five indigenous groups in measures such as cattle ownership and use of hired agricultural labor. These findings support the potential conservation value of indigenous lands while cautioning against uniform policies that homogenize indigenous ethnic groups.
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NASA Astrophysics Data System (ADS)
Roedig, Edna; Cuntz, Matthias; Huth, Andreas
2015-04-01
The effects of climatic inter-annual fluctuations and human activities on the global carbon cycle are uncertain and currently a major issue in global vegetation models. Individual-based forest gap models, on the other hand, model vegetation structure and dynamics on a small spatial (<100 ha) and large temporal scale (>1000 years). They are well-established tools to reproduce successions of highly-diverse forest ecosystems and investigate disturbances as logging or fire events. However, the parameterizations of the relationships between short-term climate variability and forest model processes are often uncertain in these models (e.g. daily variable temperature and gross primary production (GPP)) and cannot be constrained from forest inventories. We addressed this uncertainty and linked high-resolution Eddy-covariance (EC) data with an individual-based forest gap model. The forest model FORMIND was applied to three diverse tropical forest sites in the Amazonian rainforest. Species diversity was categorized into three plant functional types. The parametrizations for the steady-state of biomass and forest structure were calibrated and validated with different forest inventories. The parameterizations of relationships between short-term climate variability and forest model processes were evaluated with EC-data on a daily time step. The validations of the steady-state showed that the forest model could reproduce biomass and forest structures from forest inventories. The daily estimations of carbon fluxes showed that the forest model reproduces GPP as observed by the EC-method. Daily fluctuations of GPP were clearly reflected as a response to daily climate variability. Ecosystem respiration remains a challenge on a daily time step due to a simplified soil respiration approach. In the long-term, however, the dynamic forest model is expected to estimate carbon budgets for highly-diverse tropical forests where EC-measurements are rare.
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Estimating the risk of Amazonian forest dieback.
Rammig, Anja; Jupp, Tim; Thonicke, Kirsten; Tietjen, Britta; Heinke, Jens; Ostberg, Sebastian; Lucht, Wolfgang; Cramer, Wolfgang; Cox, Peter
2010-08-01
*Climate change will very likely affect most forests in Amazonia during the course of the 21st century, but the direction and intensity of the change are uncertain, in part because of differences in rainfall projections. In order to constrain this uncertainty, we estimate the probability for biomass change in Amazonia on the basis of rainfall projections that are weighted by climate model performance for current conditions. *We estimate the risk of forest dieback by using weighted rainfall projections from 24 general circulation models (GCMs) to create probability density functions (PDFs) for future forest biomass changes simulated by a dynamic vegetation model (LPJmL). *Our probabilistic assessment of biomass change suggests a likely shift towards increasing biomass compared with nonweighted results. Biomass estimates range between a gain of 6.2 and a loss of 2.7 kg carbon m(-2) for the Amazon region, depending on the strength of CO(2) fertilization. *The uncertainty associated with the long-term effect of CO(2) is much larger than that associated with precipitation change. This underlines the importance of reducing uncertainties in the direct effects of CO(2) on tropical ecosystems.
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Dispersal limitation induces long-term biomass collapse in overhunted Amazonian forests
Peres, Carlos A.; Emilio, Thaise; Schietti, Juliana; Desmoulière, Sylvain J. M.; Levi, Taal
2016-01-01
Tropical forests are the global cornerstone of biological diversity, and store 55% of the forest carbon stock globally, yet sustained provisioning of these forest ecosystem services may be threatened by hunting-induced extinctions of plant–animal mutualisms that maintain long-term forest dynamics. Large-bodied Atelinae primates and tapirs in particular offer nonredundant seed-dispersal services for many large-seeded Neotropical tree species, which on average have higher wood density than smaller-seeded and wind-dispersed trees. We used field data and models to project the spatial impact of hunting on large primates by ∼1 million rural households throughout the Brazilian Amazon. We then used a unique baseline dataset on 2,345 1-ha tree plots arrayed across the Brazilian Amazon to model changes in aboveground forest biomass under different scenarios of hunting-induced large-bodied frugivore extirpation. We project that defaunation of the most harvest-sensitive species will lead to losses in aboveground biomass of between 2.5–5.8% on average, with some losses as high as 26.5–37.8%. These findings highlight an urgent need to manage the sustainability of game hunting in both protected and unprotected tropical forests, and place full biodiversity integrity, including populations of large frugivorous vertebrates, firmly in the agenda of reducing emissions from deforestation and forest degradation (REDD+) programs. PMID:26811455
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NASA Astrophysics Data System (ADS)
Yan, Hao; Wang, Shao-Qiang; Yu, Kai-Liang; Wang, Bin; Yu, Qin; Bohrer, Gil; Billesbach, Dave; Bracho, Rosvel; Rahman, Faiz; Shugart, Herman H.
2017-10-01
Diffuse radiation can increase canopy light use efficiency (LUE). This creates the need to differentiate the effects of direct and diffuse radiation when simulating terrestrial gross primary production (GPP). Here, we present a novel GPP model, the diffuse-fraction-based two-leaf model (DTEC), which includes the leaf response to direct and diffuse radiation, and treats maximum LUE for shaded leaves (ɛmsh defined as a power function of the diffuse fraction (Df)) and sunlit leaves (ɛmsu defined as a constant) separately. An Amazonian rainforest site (KM67) was used to calibrate the model by simulating the linear relationship between monthly canopy LUE and Df. This showed a positive response of forest GPP to atmospheric diffuse radiation, and suggested that diffuse radiation was more limiting than global radiation and water availability for Amazon rainforest GPP on a monthly scale. Further evaluation at 20 independent AmeriFlux sites showed that the DTEC model, when driven by monthly meteorological data and MODIS leaf area index (LAI) products, explained 70% of the variability observed in monthly flux tower GPP. This exceeded the 51% accounted for by the MODIS 17A2 big-leaf GPP product. The DTEC model's explicit accounting for the impacts of diffuse radiation and soil water stress along with its parameterization for C4 and C3 plants was responsible for this difference. The evaluation of DTEC at Amazon rainforest sites demonstrated its potential to capture the unique seasonality of higher GPP during the diffuse radiation-dominated wet season. Our results highlight the importance of diffuse radiation in seasonal GPP simulation.
Plain Language SummaryAs diffuse radiation can increase canopy light use efficiency (LUE), there is a need to differentiate the effects of direct and diffuse radiation in simulating terrestrial gross primary production (GPP). A novel diffuse-fraction (Df)-based two leaf GPP model (DTEC) developed by this study considers these effects. Evaluation at 20 independent flux tower sites using the MOD15 LAI product finds that the DTEC model explains 71% of the variability observed in monthly flux GPP. Evaluation at two Amazonian tropical forest sites (KM67 and KM83) indicates this model's potential to capture the unique seasonality in GPP, e.g., higher GPP in diffuse radiation-dominated wet season, while the two-leaf LUE GPP model (He et al., 2013) cannot due to using constant LUE for sunlit and shaded leaf. The DTEC model initially simulated the linear relationship between canopy LUE and Df found at Amazon KM67 and KM83 forest sites. It shows a positive response of forest GPP to the atmosphere diffuse radiation in Amazon. Diffuse radiation was more limiting than global radiation and water for Amazon forest GPP on a seasonal scale. This differs from results of recent studies in which light-controlled leaf phenology plays the dominant role in seasonal variation of GPP in Amazonian.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.6287F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.6287F"><span>Carbon economics of LAI drive photosynthesis patterns across an Amazonian precipitation gradient</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Flack, Sophie; Williams, Mathew; Meir, Patrick; Malhi, Yadvinder</p> <p>2017-04-01</p> <p>The Amazon rainforest is an integral part of the terrestrial carbon cycle, yet whilst the physiological response of its plants to water availability is increasingly well quantified, constraints to photosynthesis through adaptive response to precipitation regime have received little attention. We use the Soil Plant Atmosphere model to apportion variation in photosynthesis to individual drivers for plots with detailed measurements of carbon cycling, leaf traits and canopy properties, along an Amazonian mean annual precipitation (MAP) gradient. We hypothesised that leaf area index (LAI) would be the principal driver of variation in photosynthesis. Differences in LAI are predicted to result from economic factors; plants balance the carbon cost of leaf construction and maintenance with assimilation potential, to maximise canopy carbon export. Model analysis showed that LAI was the primary driver of differences in GPP along the precipitation gradient, accounting for 49% of observed variation. Meteorology accounted for 19%, whilst plant traits accounted for only 5%. To explain the observed spatial trends in LAI we undertook model experiments. For each plot the carbon budget was quantified iteratively using the field measured LAI time-series of the other plots, keeping meteorology, soil and plant traits constant. The mean annual LAI achieving maximum photosynthesis and net canopy carbon export increased with MAP, reflecting observed LAI trends. At the driest site, alternative, higher LAI strategies were unsustainable. The carbon cost of leaf construction and maintenance was disproportional to GPP achieved. At high MAP, increased foliar carbon costs were remunerative and GPP was maximised by high LAI. Our evidence therefore suggests that observed LAI trends across the precipitation gradient are driven by carbon economics. Forests LAI response to temporal changes in precipitation reflects trends observed across spatial gradients, identifying LAI as a key mechanism for plant response to water availability. This research improves our understanding of the constraints on photosynthesis through plants' adaptive response to precipitation, which in light of precipitation projections, has implications for the future Amazon carbon balance.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011ERL.....6d4003N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011ERL.....6d4003N"><span>Carbon emissions from deforestation and forest fragmentation in the Brazilian Amazon</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Numata, Izaya; Cochrane, Mark A.; Souza, Carlos M., Jr.; Sales, Marcio H.</p> <p>2011-10-01</p> <p>Forest-fragmentation-related edge effects are one of the major causes of forest degradation in Amazonia and their spatio-temporal dynamics are highly influenced by annual deforestation patterns. Rapid biomass collapse due to edge effects in forest fragments has been reported in the Brazilian Amazon; however the collective impacts of this process on Amazonian carbon fluxes are poorly understood. We estimated biomass loss and carbon emissions from deforestation and forest fragmentation related to edge effects on the basis of the INPE (Brazilian National Space Research Institute) PRODES deforestation data and forest biomass volume data. The areas and ages of edge forests were calculated annually and the corresponding biomass loss and carbon emissions from these forest edges were estimated using published rates of biomass decay and decomposition corresponding to the areas and ages of edge forests. Our analysis estimated carbon fluxes from deforestation (4195 Tg C) and edge forest (126-221 Tg C) for 2001-10 in the Brazilian Amazon. The impacts of varying rates of deforestation on regional forest fragmentation and carbon fluxes were also investigated, with the focus on two periods: 2001-5 (high deforestation rates) and 2006-10 (low deforestation rates). Edge-released carbon accounted for 2.6-4.5% of deforestation-related carbon emissions. However, the relative importance of carbon emissions from forest fragmentation increased from 1.7-3.0% to 3.3-5.6% of the respective deforestation emissions between the two contrasting deforestation rates. Edge-related carbon fluxes are of increasing importance for basin-wide carbon accounting, especially as regards ongoing reducing emissions from deforestation and forest degradation (REDD) efforts in Brazilian Amazonia.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/5224665','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/5224665"><span>Distribution and morphological variation of Eleutherodactylus mercedesae Lynch & McDiarmid, 1987 (Amphibia, Anura, Leptodactylidae) with first record for Peru</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Padial, J.M.; McDiarmid, R.; De la Riva, I.</p> <p>2006-01-01</p> <p>We report new distributional information for Eleutherodactylus mercedesae in Bolivia, and provide the first record for Peru based on an adult female. This species, previously endemic to Bolivia, now ranges across about 1000 km in cloud forests on the Amazonian slopes of the Andes from southern Peru to central Bolivia. We provide the first morphological description of females based on two specimens, compare them with the male type and paratype, add some observations to the original description, and comment on variation in the species.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA572508','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA572508"><span>Environmental Security: United Nations Doctrine for Managing Environmental Issues in Military Actions. Volume 2. Selected International Treaties, Conventions and Protocols that Address Environment-Related Issues. Selected International Organizations Relevant to Environmental Security</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2000-07-01</p> <p>Poverty; growing gap between rich and poor 30. Increasing intensive use of chemical fertilizer, pesticides and detergents 31. Destruction of coral reefs ... oceans 24. Fishery depletion due to over-fishing 25. Forest fires like those in Indonesia, Australia, Amazonian and Mediterranean countries 26...to abate eutrophication and acidification , as well as pollution of the marine environment, in particular coastal areas, from land-based sources</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19373521','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19373521"><span>Do ridge habitats contribute to pteridophyte diversity in tropical montane forests? A case study from southeastern Ecuador.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kessler, Michael; Lehnert, Marcus</p> <p>2009-07-01</p> <p>We address the question to which degree ridge habitats in tropical montane forests contribute to overall plant diversity by analysing patterns of pteridophyte (i.e. lycophytes and ferns) assemblages on ridges and slopes in three montane forest sites near Podocarpus National Park, Ecuador. The analyses, which involved 158 pteridophyte species (110 terrestrial, 96 epiphytic, 48 both) from 28 plots of 20 m x 20 m (or an equivalent of 400 m(2)), showed that more species were typical of one of the three study sites than of one of the two habitats (ridge/slope). As found in previous studies, alpha diversity on ridges was lower than on slopes, accounted for by the absence of numerous species that are found on slopes. Pteridophyte assemblages on ridges were more similar across study sites than those on slopes. Thus, unlike the structurally comparable (i.e. stunted, open) Amazonian forests, the studied montane ridge forests harbour fairly homogenous pteridophytes assemblages with very few specialised species. Our study implies that slope forests are of higher conservation priority for pteridophytes in the study region than ridge habitats. However, comparative studies are needed because other geographical regions and other groups of organisms may not share this pattern.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014GMD.....7.1251F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014GMD.....7.1251F"><span>Analysing Amazonian forest productivity using a new individual and trait-based model (TFS v.1)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fyllas, N. M.; Gloor, E.; Mercado, L. M.; Sitch, S.; Quesada, C. A.; Domingues, T. F.; Galbraith, D. R.; Torre-Lezama, A.; Vilanova, E.; Ramírez-Angulo, H.; Higuchi, N.; Neill, D. A.; Silveira, M.; Ferreira, L.; Aymard C., G. A.; Malhi, Y.; Phillips, O. L.; Lloyd, J.</p> <p>2014-07-01</p> <p>Repeated long-term censuses have revealed large-scale spatial patterns in Amazon basin forest structure and dynamism, with some forests in the west of the basin having up to a twice as high rate of aboveground biomass production and tree recruitment as forests in the east. Possible causes for this variation could be the climatic and edaphic gradients across the basin and/or the spatial distribution of tree species composition. To help understand causes of this variation a new individual-based model of tropical forest growth, designed to take full advantage of the forest census data available from the Amazonian Forest Inventory Network (RAINFOR), has been developed. The model allows for within-stand variations in tree size distribution and key functional traits and between-stand differences in climate and soil physical and chemical properties. It runs at the stand level with four functional traits - leaf dry mass per area (Ma), leaf nitrogen (NL) and phosphorus (PL) content and wood density (DW) varying from tree to tree - in a way that replicates the observed continua found within each stand. We first applied the model to validate canopy-level water fluxes at three eddy covariance flux measurement sites. For all three sites the canopy-level water fluxes were adequately simulated. We then applied the model at seven plots, where intensive measurements of carbon allocation are available. Tree-by-tree multi-annual growth rates generally agreed well with observations for small trees, but with deviations identified for larger trees. At the stand level, simulations at 40 plots were used to explore the influence of climate and soil nutrient availability on the gross (ΠG) and net (ΠN) primary production rates as well as the carbon use efficiency (CU). Simulated ΠG, ΠN and CU were not associated with temperature. On the other hand, all three measures of stand level productivity were positively related to both mean annual precipitation and soil nutrient status. Sensitivity studies showed a clear importance of an accurate parameterisation of within- and between-stand trait variability on the fidelity of model predictions. For example, when functional tree diversity was not included in the model (i.e. with just a single plant functional type with mean basin-wide trait values) the predictive ability of the model was reduced. This was also the case when basin-wide (as opposed to site-specific) trait distributions were applied within each stand. We conclude that models of tropical forest carbon, energy and water cycling should strive to accurately represent observed variations in functionally important traits across the range of relevant scales.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15221436','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15221436"><span>Forest structure and carbon dynamics in Amazonian tropical rain forests.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vieira, Simone; de Camargo, Plinio Barbosa; Selhorst, Diogo; da Silva, Roseana; Hutyra, Lucy; Chambers, Jeffrey Q; Brown, I Foster; Higuchi, Niro; dos Santos, Joaquim; Wofsy, Steven C; Trumbore, Susan E; Martinelli, Luiz Antonio</p> <p>2004-08-01</p> <p>Living trees constitute one of the major stocks of carbon in tropical forests. A better understanding of variations in the dynamics and structure of tropical forests is necessary for predicting the potential for these ecosystems to lose or store carbon, and for understanding how they recover from disturbance. Amazonian tropical forests occur over a vast area that encompasses differences in topography, climate, and geologic substrate. We observed large differences in forest structure, biomass, and tree growth rates in permanent plots situated in the eastern (near Santarém, Pará), central (near Manaus, Amazonas) and southwestern (near Rio Branco, Acre) Amazon, which differed in dry season length, as well as other factors. Forests at the two sites experiencing longer dry seasons, near Rio Branco and Santarém, had lower stem frequencies (460 and 466 ha(-1) respectively), less biodiversity (Shannon-Wiener diversity index), and smaller aboveground C stocks (140.6 and 122.1 Mg C ha(-1)) than the Manaus site (626 trees ha(-1), 180.1 Mg C ha(-1)), which had less seasonal variation in rainfall. The forests experiencing longer dry seasons also stored a greater proportion of the total biomass in trees with >50 cm diameter (41-45 vs 30% in Manaus). Rates of annual addition of C to living trees calculated from monthly dendrometer band measurements were 1.9 (Manaus), 2.8 (Santarém), and 2.6 (Rio Branco) Mg C ha(-1) year(-1). At all sites, trees in the 10-30 cm diameter class accounted for the highest proportion of annual growth (38, 55 and 56% in Manaus, Rio Branco and Santarém, respectively). Growth showed marked seasonality, with largest stem diameter increment in the wet season and smallest in the dry season, though this may be confounded by seasonal variation in wood water content. Year-to-year variations in C allocated to stem growth ranged from nearly zero in Rio Branco, to 0.8 Mg C ha(-1) year(-1) in Manaus (40% of annual mean) and 0.9 Mg C ha(-1) year(-1) (33% of annual mean) in Santarém, though this variability showed no significant relation with precipitation among years. Initial estimates of the C balance of live wood including recruitment and mortality as well as growth suggests that live wood biomass is at near steady-state in Manaus, but accumulating at about 1.5 Mg C ha(-1) at the other two sites. The causes of C imbalance in living wood pools in Santarém and Rio Branco sites are unknown, but may be related to previous disturbance at these sites. Based on size distribution and growth rate differences in the three sites, we predict that trees in the Manaus forest have greater mean age (approximately 240 years) than those of the other two forests (approximately 140 years).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004GBioC..18.2009V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004GBioC..18.2009V"><span>Moisture and substrate availability constrain soil trace gas fluxes in an eastern Amazonian regrowth forest</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vasconcelos, Steel S.; Zarin, Daniel J.; Capanu, Marinela; Littell, Ramon; Davidson, Eric A.; Ishida, Francoise Y.; Santos, Elisana B.; Araújo, Maristela M.; AragãO, DéBora V.; Rangel-Vasconcelos, LíVia G. T.; de Assis Oliveira, Francisco; McDowell, William H.; de Carvalho, Claudio José R.</p> <p>2004-06-01</p> <p>Changes in land-use and climate are likely to alter moisture and substrate availability in tropical forest soils, but quantitative assessment of the role of resource constraints as regulators of soil trace gas fluxes is rather limited. The primary objective of this study was to quantify the effects of moisture and substrate availability on soil trace gas fluxes in an Amazonian regrowth forest. We measured the efflux of carbon dioxide (CO2), nitric oxide (NO), nitrous oxide (N2O), and methane (CH4) from soil in response to two experimental manipulations. In the first, we increased soil moisture availability during the dry season by irrigation; in the second, we decreased substrate availability by continuous removal of aboveground litter. In the absence of irrigation, soil CO2 efflux decreased during the dry season while irrigation maintained soil CO2 efflux levels similar to the wet season. Large variations in soil CO2 efflux consistent with a significant moisture constraint on respiration were observed in response to soil wet-up and dry-down events. Annual soil C efflux for irrigated plots was 27 and 13% higher than for control plots in 2001 and 2002, respectively. Litter removal significantly reduced soil CO2 efflux; annual soil C efflux in 2002 was 28% lower for litter removal plots compared to control plots. The annual soil C efflux:litterfall C ratio for the control treatment (4.0-5.2) was consistent with previously reported values for regrowth forests that indicate a relatively large belowground C allocation. In general, fluxes of N2O and CH4 were higher during the wet season and both fluxes increased during dry-season irrigation. There was no seasonal effect on NO fluxes. Litter removal had no significant impact on N oxide or CH4 emissions. Net soil nitrification did not respond to dry-season irrigation, but was somewhat reduced by litter removal. Overall, these results demonstrate significant soil moisture and substrate constraints on soil trace gas emissions, particularly for CO2, and suggest that climate and land-use changes that alter moisture and substrate availability are therefore likely to have an impact on atmosphere chemistry.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H51D1294R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H51D1294R"><span>Downstream impacts of a Central Amazonian hydroelectric dam on tree growth and mortality in floodplain forests</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Resende, A. F. D.; Silva, T. S. F.; Silva, J. D. S.; Piedade, M. T. F.; Streher, A. S.; Ferreira-Ferreira, J.; Schongart, J.</p> <p>2017-12-01</p> <p>The flood pulse of large Amazonian Rivers is characterized by predictable high- and low-water periods during the annual cycle, and is the main driving force in the floodplains regulating decomposition, nutrient cycles, productivity, life cycles and growth rhythms of floodplains' biota. Over at least 20 millions of years, tree species in these ecosystems developed complex adaptative mechanisms to tolerate flooding, such as the tree species Macrolobium acaciifolium (Fabaceae) and Eschweilera tenuifolia (Lecythidaceae) occupying the lower topographic positions in the floodplain forests along the oligothrophic black-water rivers. Tree growth occurs mainly during terrestrial phase, while during the aquatic phase the anoxic conditions result into a cambial dormancy and formation of annual tree rings. The hydroelectric dam Balbina which was installed in the Uatumã River (central Amazonia) during the 1980s altered significantly the flood pulse regime resulting into higher minimum and lower maximum annual water levels. The suppression of the terrestrial phase caused large-scale mortality of flood-adapted trees growing on the lower topographic positions, as evidenced by radiocarbon dating and cross-dating techniques (dendrochronology). In this study we estimated the extension of dead forests using high resolution ALOS/PALSAR radar images, for their detection along a fluvial distance of more than 280 km downstream of the power plant. Further we analyzed tree growth of 60 living individuals of E. tenuifolia by tree-ring analyses comparing the post- and pre-dam periods. We evaluated the impacts of the altered hydrological regime on tree growth considering ontogenetic effects and the fluvial distance of the trees to the dam. Since the Balbina power plant started operating the associated igapó forests lost about 11% of its cover. We found a significant reduction of tree growth of E. tenuifolia during the post-dam period as a consequence of the increasing aquatic phase duration. This impact was stronger for younger trees (<200 yr) and for those growing closer to the hydroelectric dam (<100 km distance). Considering the planning of construction of several dozen dams in the Amazon there is an urgent need to consider these downstream impacts in all discussions of hydroelectric power plants implementation and operation.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110007186','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110007186"><span>Stratifying Tropical Fires by Land Cover: Insights into Amazonian Fires, Aerosol Loading, and Regional Deforestation</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>TenHoeve, J. E.; Remer, L. A.; Jacobson, M. Z.</p> <p>2010-01-01</p> <p>This study analyzes changes in the number of fires detected on forest, grass, and transition lands during the 2002-2009 biomass burning seasons using fire detection data and co-located land cover classifications from the Moderate Resolution Imaging Spectroradiometer (MODIS). We find that the total number of detected fires correlates well with MODIS mean aerosol optical depth (AOD) from year to year, in accord with other studies. However, we also show that the ratio of forest to savanna fires varies substantially from year to year. Forest fires have trended downward, on average, since the beginning of 2006 despite a modest increase in 2007. Our study suggests that high particulate matter loading detected in 2007 was likely due to a large number of savanna/agricultural fires that year. Finally, we illustrate that the correlation between annual Brazilian deforestation estimates and MODIS fires is considerably higher when fires are stratified by MODIS-derived land cover classifications.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3161596','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3161596"><span>Land-use poverty traps identified in shifting cultivation systems shape long-term tropical forest cover</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Coomes, Oliver T.; Takasaki, Yoshito; Rhemtulla, Jeanine M.</p> <p>2011-01-01</p> <p>In this article we illustrate how fine-grained longitudinal analyses of land holding and land use among forest peasant households in an Amazonian village can enrich our understanding of the poverty/land cover nexus. We examine the dynamic links in shifting cultivation systems among asset poverty, land use, and land cover in a community where poverty is persistent and primary forests have been replaced over time—with community enclosure—by secondary forests (i.e., fallows), orchards, and crop land. Land cover change is assessed using aerial photographs/satellite imagery from 1965 to 2007. Household and plot level data are used to track land holding, portfolios, and use as well as land cover over the past 30 y, with particular attention to forest status (type and age). Our analyses find evidence for two important types of “land-use” poverty traps—a “subsistence crop” trap and a “short fallow” trap—and indicate that the initial conditions of land holding by forest peasants have long-term effects on future forest cover and household welfare. These findings suggest a new mechanism driving poverty traps: insufficient initial land holdings induce land use patterns that trap households in low agricultural productivity. Path dependency in the evolution of household land portfolios and land use strategies strongly influences not only the wellbeing of forest people but also the dynamics of tropical deforestation and secondary forest regrowth. PMID:21873179</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NatGe...8..567A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NatGe...8..567A"><span>Landscape biogeochemistry reflected in shifting distributions of chemical traits in the Amazon forest canopy</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Asner, Gregory P.; Anderson, Christopher B.; Martin, Roberta E.; Tupayachi, Raul; Knapp, David E.; Sinca, Felipe</p> <p>2015-07-01</p> <p>Tropical forest functional diversity, which is a measure of the diversity of organismal interactions with the environment, is poorly understood despite its importance for linking evolutionary biology to ecosystem biogeochemistry. Functional diversity is reflected in functional traits such as the concentrations of different compounds in leaves or the density of leaf mass, which are related to plant activities such as plant defence, nutrient cycling, or growth. In the Amazonian lowlands, river movement and microtopography control nutrient mobility, which may influence functional trait distributions. Here we use airborne laser-guided imaging spectroscopy to develop maps of 16 forest canopy traits, throughout four large landscapes that harbour three common forest community types on the Madre de Dios and Tambopata rivers in southwestern Amazonia. Our maps, which are based on quantitative chemometric analysis of forest canopies with visible-to-near infrared (400-2,500 nm) spectroscopy, reveal substantial variation in canopy traits and their distributions within and among forested landscapes. Forest canopy trait distributions are arranged in a nested pattern, with location along rivers controlling trait variation between different landscapes, and microtopography controlling trait variation within landscapes. We suggest that processes of nutrient deposition and depletion drive increasing phosphorus limitation, and a corresponding increase in plant defence, in an eastward direction from the base of the Andes into the Amazon Basin.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27497033','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27497033"><span>Litter and nutrient flows in tropical upland forest flooded by a hydropower plant in the Amazonian basin.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pereira, Guilherme Henrique A; Jordão, Henos Carlos K; Silva, Vanessa Francieli V; Pereira, Marcos Gervasio</p> <p>2016-12-01</p> <p>Extensive areas in the Brazilian Amazon have been flooded for the construction of hydroelectric dams. However, the water regime of these areas affects the dynamics of igarapés (streams) in adjacent terra firme (upland forests). When the reservoirs are filled, the water levels of streams rise above the normal levels and upland bank forests are flooded. We investigated how this flooding affects the litterfall and nutrient input in the upland forests upstream of a hydroelectric dam reservoir in the Central Amazonia. When the reservoir was filled, the forests were flooded and produced more than twice the litter (8.80Mg·ha -1 yr -1 ), with three times more leaves (6.36Mg·ha -1 yr -1 ) than when they were not flooded (4.20 and 1.92Mg·ha -1 yr -1 , respectively). During flooding, the decomposition rate was four times lower in flooded forests (0.328g·g -1 yr -1 ) than in control forests (1.460g·g -1 yr -1 ). Despite this, the flooding did not favor litter or nutrient accumulation. Therefore, dam construction changes the organic matter and nutrient cycling in upland Amazon rainforests. This may influence the important role that they play in organic matter dynamics and could have consequences for the regional carbon balance and, ultimately, global climate. Copyright © 2016 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRG..120.2095C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRG..120.2095C"><span>Forest edge burning in the Brazilian Amazon promoted by escaping fires from managed pastures</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cano-Crespo, Ana; Oliveira, Paulo J. C.; Boit, Alice; Cardoso, Manoel; Thonicke, Kirsten</p> <p>2015-10-01</p> <p>Understanding to what extent different land uses influence fire occurrence in the Amazonian forest is particularly relevant for its conservation. We evaluate the relationship between forest fires and different anthropogenic activities linked to a variety of land uses in the Brazilian states of Mato Grosso, Pará, and Rondônia. We combine the new high-resolution (30 m) TerraClass land use database with Moderate Resolution Imaging Spectroradiometer burned area data for 2008 and the extreme dry year of 2010. Excluding the non-forest class, most of the burned area was found in pastures, primary and secondary forests, and agricultural lands across all three states, while only around 1% of the total was located in deforested areas. The trend in burned area did not follow the declining deforestation rates from 2001 to 2010, and the spatial overlap between deforested and burned areas was only 8% on average. This supports the claim of deforestation being disconnected from burning since 2005. Forest degradation showed an even lower correlation with burned area. We found that fires used in managing pastoral and agricultural lands that escape into the neighboring forests largely contribute to forest fires. Such escaping fires are responsible for up to 52% of the burned forest edges adjacent to burned pastures and up to 22% of the burned forest edges adjacent to burned agricultural fields, respectively. Our findings call for the development of control and monitoring plans to prevent fires from escaping from managed lands into forests to support effective land use and ecosystem management.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.B31I..08A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.B31I..08A"><span>Updated Global Patterns of Drought and Heat-Induced Forest Die-off, and Ecohydrological Feedbacks</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Allen, C. D.</p> <p>2011-12-01</p> <p>Ongoing climate changes - particularly increases in mean temperatures as well as frequencies, durations, and severities of extreme drought and heat - can amplify tree physiological stress and thereby drive increases in both background tree mortality rates and episodes of rapid, broad-scale forest die-off. Updates are presented to a recent global synthesis of documented tree mortality episodes attributed to drought and/or heat, further expanding the documented spatial distribution and demonstrating the vulnerability of all major forest types from tropical moist forests and savannas to temperate and boreal forests. Given that anthropogenic climate change is projected to drive substantial increases in both mean temperatures and the frequency/duration/severity of extreme drought and heat in many regions, recent episodes of broad-scale drought-induced forest mortality may reflect increasing global risks of forest die-off, even in environments not normally considered water-limited. Since vegetation cover patterns are closely and interactively linked with ecosystem water fluxes, episodes of massive forest die-off can be expected to significantly affect ecohydrological patterns and processes, ranging from runoff and erosion to evaporation and transpiration, often with nonlinear threshold responses expected. Diverse examples of such feedbacks between climate-induced forest mortality and ecohydrology are presented, ranging from detailed observations of linked changes in vegetation, runoff, and erosion in response to forest mortality in the southwestern US to Western Australia and Amazonian rainforest water cycling. Current research efforts to address the large knowledge gaps that at present hinder our ability to predict climate-induced forest mortality and associated ecohydrological responses are discussed.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRD..122.8410F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRD..122.8410F"><span>Influence of landscape heterogeneity on water available to tropical forests in an Amazonian catchment and implications for modeling drought response</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fang, Yilin; Leung, L. Ruby; Duan, Zhuoran; Wigmosta, Mark S.; Maxwell, Reed M.; Chambers, Jeffrey Q.; Tomasella, Javier</p> <p>2017-08-01</p> <p>The Amazon basin has experienced periodic droughts in the past, and intense and frequent droughts are predicted in the future. Landscape heterogeneity could play an important role in how tropical forests respond to drought by influencing water available to plants. Using the one-dimensional ACME Land Model and the three-dimensional ParFlow variably saturated flow model, numerical experiments were performed for a catchment in central Amazon to elucidate processes that influence water available for plant use and provide insights for improving Earth system models. Results from ParFlow show that topography has a dominant influence on groundwater table and runoff through lateral flow. Without any representations of lateral processes, ALM simulates very different seasonal variations in groundwater table and runoff compared to ParFlow even if it is able to reproduce the long-term spatial average groundwater table of ParFlow through simple parameter calibration. In the ParFlow simulations, even in the plateau with much deeper water table depth during the dry season in the drought year of 2005, plant transpiration is not water stressed as the soil saturation is still sufficient for the stomata to be fully open based on the empirical wilting formulation in the models. This finding is insensitive to uncertainty in atmospheric forcing and soil parameters, but the empirical wilting formulation is an important factor that should be addressed using observations and modeling of coupled plant hydraulics-soil hydrology processes in future studies. The results could be applicable to other catchments in the Amazon basin with similar seasonal variability and hydrologic regimes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014GMDD....7.7823R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014GMDD....7.7823R"><span>Modelling climate change responses in tropical forests: similar productivity estimates across five models, but different mechanisms and responses</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rowland, L.; Harper, A.; Christoffersen, B. O.; Galbraith, D. R.; Imbuzeiro, H. M. A.; Powell, T. L.; Doughty, C.; Levine, N. M.; Malhi, Y.; Saleska, S. R.; Moorcroft, P. R.; Meir, P.; Williams, M.</p> <p>2014-11-01</p> <p>Accurately predicting the response of Amazonia to climate change is important for predicting changes across the globe. However, changes in multiple climatic factors simultaneously may result in complex non-linear responses, which are difficult to predict using vegetation models. Using leaf and canopy scale observations, this study evaluated the capability of five vegetation models (CLM3.5, ED2, JULES, SiB3, and SPA) to simulate the responses of canopy and leaf scale productivity to changes in temperature and drought in an Amazonian forest. The models did not agree as to whether gross primary productivity (GPP) was more sensitive to changes in temperature or precipitation. There was greater model-data consistency in the response of net ecosystem exchange to changes in temperature, than in the response to temperature of leaf area index (LAI), net photosynthesis (An) and stomatal conductance (gs). Modelled canopy scale fluxes are calculated by scaling leaf scale fluxes to LAI, and therefore in this study similarities in modelled ecosystem scale responses to drought and temperature were the result of inconsistent leaf scale and LAI responses among models. Across the models, the response of An to temperature was more closely linked to stomatal behaviour than biochemical processes. Consequently all the models predicted that GPP would be higher if tropical forests were 5 °C colder, closer to the model optima for gs. There was however no model consistency in the response of the An-gs relationship when temperature changes and drought were introduced simultaneously. The inconsistencies in the An-gs relationships amongst models were caused by to non-linear model responses induced by simultaneous drought and temperature change. To improve the reliability of simulations of the response of Amazonian rainforest to climate change the mechanistic underpinnings of vegetation models need more complete validation to improve accuracy and consistency in the scaling of processes from leaf to canopy.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3398689','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3398689"><span>Contrasting Colonist and Indigenous Impacts on Amazonian Forests</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>LU, FLORA; GRAY, CLARK; BILSBORROW, RICHARD E.; MENA, CARLOS F.; ERLIEN, CHRISTINE M.; BREMNER, JASON; BARBIERI, ALISSON; WALSH, STEPHEN J.</p> <p>2012-01-01</p> <p>To examine differences in land use and environmental impacts between colonist and indigenous populations in the northern Ecuadorian Amazon, we combined data from household surveys and remotely sensed imagery that was collected from 778 colonist households in 64 colonization sectors, and 499 households from five indigenous groups in 36 communities. Overall, measures of deforestation and forest fragmentation were significantly greater for colonists than indigenous peoples. On average, colonist households had approximately double the area in agriculture and cash crops and 5.5 times the area in pasture as indigenous households. Nevertheless, substantial variation in land-use patterns existed among the five indigenous groups in measures such as cattle ownership and use of hired agricultural labor. These findings support the potential conservation value of indigenous lands while cautioning against uniform policies that homogenize indigenous ethnic groups. PMID:20337669</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3492346','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3492346"><span>Insight into the Wild Origin, Migration and Domestication History of the Fine Flavour Nacional Theobroma cacao L. Variety from Ecuador</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Loor Solorzano, Rey Gaston; Fouet, Olivier; Lemainque, Arnaud; Pavek, Sylvana; Boccara, Michel; Argout, Xavier; Amores, Freddy; Courtois, Brigitte; Risterucci, Ange Marie; Lanaud, Claire</p> <p>2012-01-01</p> <p>Ecuador’s economic history has been closely linked to Theobroma cacao L cultivation, and specifically to the native fine flavour Nacional cocoa variety. The original Nacional cocoa trees are presently in danger of extinction due to foreign germplasm introductions. In a previous work, a few non-introgressed Nacional types were identified as potential founders of the modern Ecuadorian cocoa population, but so far their origin could not be formally identified. In order to determine the putative centre of origin of Nacional and trace its domestication history, we used 80 simple sequence repeat (SSR) markers to analyse the relationships between these potential Nacional founders and 169 wild and cultivated cocoa accessions from South and Central America. The highest genetic similarity was observed between the Nacional pool and some wild genotypes from the southern Amazonian region of Ecuador, sampled along the Yacuambi, Nangaritza and Zamora rivers in Zamora Chinchipe province. This result was confirmed by a parentage analysis. Based on our results and on data about pre-Columbian civilization and Spanish colonization history of Ecuador, we determined, for the first time, the possible centre of origin and migration events of the Nacional variety from the Amazonian area until its arrival in the coastal provinces. As large unexplored forest areas still exist in the southern part of the Ecuadorian Amazonian region, our findings could provide clues as to where precious new genetic resources could be collected, and subsequently used to improve the flavour and disease resistance of modern Ecuadorian cocoa varieties. PMID:23144883</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23144883','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23144883"><span>Insight into the wild origin, migration and domestication history of the fine flavour Nacional Theobroma cacao L. variety from Ecuador.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Loor Solorzano, Rey Gaston; Fouet, Olivier; Lemainque, Arnaud; Pavek, Sylvana; Boccara, Michel; Argout, Xavier; Amores, Freddy; Courtois, Brigitte; Risterucci, Ange Marie; Lanaud, Claire</p> <p>2012-01-01</p> <p>Ecuador's economic history has been closely linked to Theobroma cacao L cultivation, and specifically to the native fine flavour Nacional cocoa variety. The original Nacional cocoa trees are presently in danger of extinction due to foreign germplasm introductions. In a previous work, a few non-introgressed Nacional types were identified as potential founders of the modern Ecuadorian cocoa population, but so far their origin could not be formally identified. In order to determine the putative centre of origin of Nacional and trace its domestication history, we used 80 simple sequence repeat (SSR) markers to analyse the relationships between these potential Nacional founders and 169 wild and cultivated cocoa accessions from South and Central America. The highest genetic similarity was observed between the Nacional pool and some wild genotypes from the southern Amazonian region of Ecuador, sampled along the Yacuambi, Nangaritza and Zamora rivers in Zamora Chinchipe province. This result was confirmed by a parentage analysis. Based on our results and on data about pre-Columbian civilization and Spanish colonization history of Ecuador, we determined, for the first time, the possible centre of origin and migration events of the Nacional variety from the Amazonian area until its arrival in the coastal provinces. As large unexplored forest areas still exist in the southern part of the Ecuadorian Amazonian region, our findings could provide clues as to where precious new genetic resources could be collected, and subsequently used to improve the flavour and disease resistance of modern Ecuadorian cocoa varieties.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4466577','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4466577"><span>Ground-Vegetation Clutter Affects Phyllostomid Bat Assemblage Structure in Lowland Amazonian Forest</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Marciente, Rodrigo; Bobrowiec, Paulo Estefano D.; Magnusson, William E.</p> <p>2015-01-01</p> <p>Vegetation clutter is a limiting factor for bats that forage near ground level, and may determine the distribution of species and guilds. However, many studies that evaluated the effects of vegetation clutter on bats have used qualitative descriptions rather than direct measurements of vegetation density. Moreover, few studies have evaluated the effect of vegetation clutter on a regional scale. Here, we evaluate the influence of the physical obstruction of vegetation on phyllostomid-bat assemblages along a 520 km transect in continuous Amazonian forest. We sampled bats using mist nets in eight localities during 80 nights (3840 net-hours) and estimated the ground-vegetation density with digital photographs. The total number of species, number of animalivorous species, total number of frugivorous species, number of understory frugivorous species, and abundance of canopy frugivorous bats were negatively associated with vegetation clutter. The bat assemblages showed a nested structure in relation to degree of clutter, with animalivorous and understory frugivorous bats distributed throughout the vegetation-clutter gradient, while canopy frugivores were restricted to sites with more open vegetation. The species distribution along the gradient of vegetation clutter was not closely associated with wing morphology, but aspect ratio and wing load differed between frugivores and animalivores. Vegetation structure plays an important role in structuring assemblages of the bats at the regional scale by increasing beta diversity between sites. Differences in foraging strategy and diet of the guilds seem to have contributed more to the spatial distribution of bats than the wing characteristics of the species alone. PMID:26066654</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040161149&hterms=biomass+forest&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dbiomass%2Bforest','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040161149&hterms=biomass+forest&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dbiomass%2Bforest"><span>The Spatial Distribution of Forest Biomass in the Brazilian Amazon: A Comparison of Estimates</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Houghton, R. A.; Lawrence, J. L.; Hackler, J. L.; Brown, S.</p> <p>2001-01-01</p> <p>The amount of carbon released to the atmosphere as a result of deforestation is determined, in part, by the amount of carbon held in the biomass of the forests converted to other uses. Uncertainty in forest biomass is responsible for much of the uncertainty in current estimates of the flux of carbon from land-use change. We compared several estimates of forest biomass for the Brazilian Amazon, based on spatial interpolations of direct measurements, relationships to climatic variables, and remote sensing data. We asked three questions. First, do the methods yield similar estimates? Second, do they yield similar spatial patterns of distribution of biomass? And, third, what factors need most attention if we are to predict more accurately the distribution of forest biomass over large areas? Amazonian forests (including dead and below-ground biomass) vary by more than a factor of two, from a low of 39 PgC to a high of 93 PgC. Furthermore, the estimates disagree as to the regions of high and low biomass. The lack of agreement among estimates confirms the need for reliable determination of aboveground biomass over large areas. Potential methods include direct measurement of biomass through forest inventories with improved allometric regression equations, dynamic modeling of forest recovery following observed stand-replacing disturbances (the approach used in this research), and estimation of aboveground biomass from airborne or satellite-based instruments sensitive to the vertical structure plant canopies.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ERL....12b4012H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ERL....12b4012H"><span>Using spatial statistics to identify emerging hot spots of forest loss</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Harris, Nancy L.; Goldman, Elizabeth; Gabris, Christopher; Nordling, Jon; Minnemeyer, Susan; Ansari, Stephen; Lippmann, Michael; Bennett, Lauren; Raad, Mansour; Hansen, Matthew; Potapov, Peter</p> <p>2017-02-01</p> <p>As sources of data for global forest monitoring grow larger, more complex and numerous, data analysis and interpretation become critical bottlenecks for effectively using them to inform land use policy discussions. Here in this paper, we present a method that combines big data analytical tools with Emerging Hot Spot Analysis (ArcGIS) to identify statistically significant spatiotemporal trends of forest loss in Brazil, Indonesia and the Democratic Republic of Congo (DRC) between 2000 and 2014. Results indicate that while the overall rate of forest loss in Brazil declined over the 14-year time period, spatiotemporal patterns of loss shifted, with forest loss significantly diminishing within the Amazonian states of Mato Grosso and Rondônia and intensifying within the cerrado biome. In Indonesia, forest loss intensified in Riau province in Sumatra and in Sukamara and West Kotawaringin regencies in Central Kalimantan. Substantial portions of West Kalimantan became new and statistically significant hot spots of forest loss in the years 2013 and 2014. Similarly, vast areas of DRC emerged as significant new hot spots of forest loss, with intensified loss radiating out from city centers such as Beni and Kisangani. While our results focus on identifying significant trends at the national scale, we also demonstrate the scalability of our approach to smaller or larger regions depending on the area of interest and specific research question involved. When combined with other contextual information, these statistical data models can help isolate the most significant clusters of loss occurring over dynamic forest landscapes and provide more coherent guidance for the allocation of resources for forest monitoring and enforcement efforts.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1361963-airborne-observations-reveal-elevational-gradient-tropical-forest-isoprene-emissions','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1361963-airborne-observations-reveal-elevational-gradient-tropical-forest-isoprene-emissions"><span>Airborne observations reveal elevational gradient in tropical forest isoprene emissions</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Gu, Dasa; Guenther, Alex B.; Shilling, John E.; ...</p> <p>2017-05-23</p> <p>Terrestrial vegetation emits vast quantities of volatile organic compounds (VOCs) to he atmosphere1-3, which influence oxidants and aerosols leading to complex feedbacks on air quality and climate4-6. Isoprene dominates global non-methane VOC emissions with tropical regions contributing ~80% of global isoprene emissions2. Isoprene emission rates vary over several orders of magnitude for different plant species, and characterizing this immense biological chemodiversity is a challenge for estimating isoprene emission from tropical forests. Here we present the isoprene emission estimates from aircraft direct eddy covariance measurements over the pristine Amazon forest. We report isoprene emission rates that are 3 times higher thanmore » satellite top-down estimates and 35% higher than model predictions based on satellite land cover and vegetation specific emission factors (EFs). The results reveal strong correlations between observed isoprene emission rates and terrain elevations which are confirmed by similar correlations between satellite-derived isoprene emissions and terrain elevations. We propose that the elevational gradient in the Amazonian forest isoprene emission capacity is determined by plant species distributions and can explain a substantial degree of isoprene emission variability in tropical forests. Finally, we apply this approach over the central Amazon and use a model to demonstrate the impacts on regional air quality.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28954174','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28954174"><span>Sampling procedures for inventory of commercial volume tree species in Amazon Forest.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Netto, Sylvio P; Pelissari, Allan L; Cysneiros, Vinicius C; Bonazza, Marcelo; Sanquetta, Carlos R</p> <p>2017-01-01</p> <p>The spatial distribution of tropical tree species can affect the consistency of the estimators in commercial forest inventories, therefore, appropriate sampling procedures are required to survey species with different spatial patterns in the Amazon Forest. For this, the present study aims to evaluate the conventional sampling procedures and introduce the adaptive cluster sampling for volumetric inventories of Amazonian tree species, considering the hypotheses that the density, the spatial distribution and the zero-plots affect the consistency of the estimators, and that the adaptive cluster sampling allows to obtain more accurate volumetric estimation. We use data from a census carried out in Jamari National Forest, Brazil, where trees with diameters equal to or higher than 40 cm were measured in 1,355 plots. Species with different spatial patterns were selected and sampled with simple random sampling, systematic sampling, linear cluster sampling and adaptive cluster sampling, whereby the accuracy of the volumetric estimation and presence of zero-plots were evaluated. The sampling procedures applied to species were affected by the low density of trees and the large number of zero-plots, wherein the adaptive clusters allowed concentrating the sampling effort in plots with trees and, thus, agglutinating more representative samples to estimate the commercial volume.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27353133','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27353133"><span>Little effects of reduced-impact logging on insect communities in eastern Amazonia.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nogueira, Denis Silva; Calvão, Lenize Batista; de Assis Montag, Luciano Fogaça; Juen, Leandro; De Marco, Paulo</p> <p>2016-07-01</p> <p>Selective logging has become a major source of threats to tropical forest, bringing challenges for both ecologists and managers to develop low-impact forestry. Reduced-impact logging (RIL) is a prominent activity accounting for such forestry practices to prevent strong forest disturbances. Our aims were to evaluate the effects of RIL on insect communities of forested streams from Eastern Amazon and to test the hypothesis of negative effects of RIL on species richness, abundance, and functional feeding groups of aquatic insect assemblages. Neither of the evaluated metrics of the studied assemblages were negatively affected by RIL. Environmental metrics, such as substrate heterogeneity, woody canopy cover, and hill slope height, varied more among RIL streams than in reference streams, indicating a gradient according to logging impacts, and are suitable candidates to monitor RIL impacts in Amazonian streams. In addition, the PHI index also varied among REF and RIL, according to age class and year of logging, which could reflect trends to recover the forest structure after logging in a time frame of only 10 years. We conclude that RIL impacts have not had detrimental impacts on insect communities, but have changed little of the environmental conditions, especially of the riparian vegetation around streams.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1361963','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1361963"><span></span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Gu, Dasa; Guenther, Alex B.; Shilling, John E.</p> <p></p> <p>Terrestrial vegetation emits vast quantities of volatile organic compounds (VOCs) to he atmosphere1-3, which influence oxidants and aerosols leading to complex feedbacks on air quality and climate4-6. Isoprene dominates global non-methane VOC emissions with tropical regions contributing ~80% of global isoprene emissions2. Isoprene emission rates vary over several orders of magnitude for different plant species, and characterizing this immense biological chemodiversity is a challenge for estimating isoprene emission from tropical forests. Here we present the isoprene emission estimates from aircraft direct eddy covariance measurements over the pristine Amazon forest. We report isoprene emission rates that are 3 times higher thanmore » satellite top-down estimates and 35% higher than model predictions based on satellite land cover and vegetation specific emission factors (EFs). The results reveal strong correlations between observed isoprene emission rates and terrain elevations which are confirmed by similar correlations between satellite-derived isoprene emissions and terrain elevations. We propose that the elevational gradient in the Amazonian forest isoprene emission capacity is determined by plant species distributions and can explain a substantial degree of isoprene emission variability in tropical forests. Finally, we apply this approach over the central Amazon and use a model to demonstrate the impacts on regional air quality.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21801842','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21801842"><span>Molecular phylogeny, biogeography and insights into the origin of parthenogenesis in the Neotropical genus Leposoma (Squamata: Gymnophthalmidae): Ancient links between the Atlantic Forest and Amazonia.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pellegrino, Katia C M; Rodrigues, Miguel T; Harris, D James; Yonenaga-Yassuda, Yatiyo; Sites, Jack W</p> <p>2011-11-01</p> <p>Leposoma is a conspicuous component of leaf litter herpetofauna of South and Central American rainforests. The 15 bisexual and one parthenogenetic species are allocated to the parietale and scincoides groups based on morphology. Phylogenetic analyses of 1830 bp (mtDNA+nuclear) were performed on 63 specimens of four species from Amazonian and Panamanian rainforests, and six species and one undescribed form from the Atlantic Forest. Different methods of tree reconstruction were explored, with Anotosaura vanzolinia and Colobosauroides cearensis as outgroups. The monophyly of the parietale and scincoides groups is strongly supported. Contrary to previous hypotheses suggesting a recent contact between Atlantic and Amazon forests, our estimates point to an initial split in Miocene. The position of Leposoma baturitensis, endemic to relictual forests in the semiarid Caatingas northeastern Brazil, and its divergence from the remaining species of the Atlantic Forest, suggests an ancient isolation with no indication of a secondary contact with forests of the eastern coast. Our data do not permit unambiguous assignment of parental species of the unisexual Leposoma percarinatum or the mechanism involved in the origin of parthenogenesis, but revealed two highly divergent diploid and triploid lineages within L. percarinatum, indicating that the unisexuals represent a species complex. Copyright © 2011 Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMEP33D..07A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMEP33D..07A"><span>The impact of rise of the Andes and Amazon landscape evolution on diversification of lowland terra-firme forest birds</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aleixo, A.; Wilkinson, M. J.</p> <p>2011-12-01</p> <p>Since the 19th Century, the unmatched biological diversity of Amazonia has stimulated a diverse set of hypotheses accounting for patterns of species diversity and distribution in mega-diverse tropical environments. Unfortunately, the evidence supporting particular hypotheses to date is at best described as ambiguous, and no generalizations have emerged yet, mostly due to the lack of comprehensive comparative phylogeographic studies with thorough trans-Amazonian sampling of lineages. Here we report on spatial and temporal patterns of diversification estimated from mitochondrial gene trees for 31 lineages of birds associated with upland terra-firme forest, the dominant habitat in modern lowland Amazonia. The results confirm the pervasive role of Amazonian rivers as primary barriers separating sister lineages of birds, and a protracted spatio-temporal pattern of diversification, with a gradual reduction of earlier (1st and 2nd) and older (> 2 mya) splits associated with each lineage in an eastward direction (the easternmost tributaries of the Amazon, the Xingu and Tocantins Rivers, are not associated with any splits older than > 2 mya). This "younging-eastward" pattern may have an abiotic explanation related to landscape evolution. Triggered by a new pulse of Andean uplift, it has been proposed that modern Amazon basin landscapes may have evolved successively eastward, away from the mountain chain, starting ~10 mya. This process was likely based on the deposition of vast fluvial sediment masses, known as megafans, which apparently extended in series progressively eastward from Andean sources. The effects on drainage patterns are apparent from the location of axial rivers such as the Negro / Orinoco and Madeira which lie at the distal ends of major megafan ramparts at cratonic margins furthest from the Andes. Megafan extension plausibly explains the progressive extinction of the original Pebas wetland of west-central Amazonia by the present fluvial landsurfaces where upland terra-firme forest develop. The youngest landsurfaces thus appear to lie furthest from the mountains. In this scenario major drainages were also reoriented in wholesale fashion from a northward (Caribbean) outlet to a generally eastward, Atlantic Ocean outlet. More importantly, other major river courses in western-central Amazonia will have been established at progressively younger dates with distance eastward. The bird DNA data appears to confirm the role of Amazonian rivers as primary diversification barriers, and thus probably as promoters of bird speciation. We show for the first time that a general spatio-temporal pattern of diversification for terra-firme lineages in the Amazon is associated with rivers of apparently different ages ("younging-eastward"), and furthermore parallels a specific scenario of regional drainage evolution.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMEP41C0632C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMEP41C0632C"><span>Vegetation and climate changes in western Amazonia during a previous Interglacial- Glacial transition</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cardenas, M. L.; Gosling, W. D.; Sherlock, S. C.; Poole, I.; Pennington, R. T.</p> <p>2009-12-01</p> <p>Amazonia is one of the most biodiverse areas of the world and its vegetation plays a crucial role in controlling the global climate through the regulation of the levels of atmospheric CO2. However, Amazonian ecosystems and their role in the climate system are threatened by ongoing the human impact (already estimated loss of 60% of the species in western Amazonia) and predicted climate change (+1.1-6.4oC by 2100). Unfortunately, there is absence of data relating to the ecological baseline function and response to global climate change of western Amazonian ecosystems in the absence of humans. To help anticipate the impact of future climate change predictions an improved understanding of the natural responses of tropical vegetation to known past climate change is required. Here we present the first study that shows the response of pristine tropical ecosystems in western Amazonia biodiversity hotspot to a major global climate change event (a Quaternary Interglacial-Glacial transition). Pleistocene lake/swamp sediments preserved at the Erazo study site (Lat. 00o 33’S, Long. 077o 52’W, 1927m alt.) today within tropical cloud forest vegetation provide a unique opportunity to examine the impact of past climate shifts. The sediment are >40,000 years old (radiocarbon infinite) and younger than 1 million years (presence of Alder biomarker) and consist of organic layers interbedded with volcanic ash (tephra). This study presents data from multiple proxies (fossil pollen, wood macrofossils and charcoal) to establish a comprehensive picture of regional and local vegetation change prior to human arrival. Our data show a change of vegetation from palm-dominated forest indicative of warm and wet conditions similar to the present at the base of this record, to a forest dominated by Podocarpus sp. suggesting cold and wet conditions at the top of the record. The transition between these two vegetation communities appears to be progressive with small sharp changes along the ecological succession. Fire activity appears to be minor through the record associated only with volcanic events (tephra layers). We conclude that western Amazonian vegetation was effected by Pleistocene global climate change. The Erazo record shows the progression of the vegetation from warm/wet Interglacial-like period similar to the present, to a colder and wetter Glacial-like period. This magnitude of change agrees with similar magnitude changes inferred for the last glacial-interglacial transition at 14,700-9,000 calendar years BP. We also establish for the first time that no natural fire occurred in western Amazonia in the absence of humans, under interglacial or glacial conditions, without volcanic eruptions acting as a source of ignition.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19880040037&hterms=dry+forest&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Ddry%2Bforest','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19880040037&hterms=dry+forest&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Ddry%2Bforest"><span>Regional aerosol chemistry of the Amazon Basin during the dry season</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Talbot, R. W.; Harriss, R. C.; Andreae, M. O.; Andreae, T. W.</p> <p>1988-01-01</p> <p>The distribution and chemical composition of the atmospheric aerosol over the Amazon Basin forest were determined during the 1985 July-August dry season, using data on the aerosol chemical constituent concentration collected during the NASA Global Tropospheric Experiment Amazon Boundary Layer Experiment 2A mission. The results of the analyses suggest that there is a remarkable compositional and spatial homogeneity of the atmospheric aerosol on an extensive regional scale. Particulate organic carbon is the dominant component of the atmospheric aerosol, exhibiting an average concentration of about 740 nmol/cu m in the mixed layer and about 220 nmol/cu m in free tropospheric air. Oxalate and SO4(2-) exhibited the greatest enrichment in the mixed layer, while Cl(-) showed essentially no enrichment. The aerosol in the Amazonian atmosphere is essentially acid-base neutral, primarily as a result of incorporation of NH(+), which is presumably derived from NH3 released by the forest ecosystem.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017NatCo...815519W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017NatCo...815519W"><span>Amazonian forest-savanna bistability and human impact</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wuyts, Bert; Champneys, Alan R.; House, Joanna I.</p> <p>2017-05-01</p> <p>A bimodal distribution of tropical tree cover at intermediate precipitation levels has been presented as evidence of fire-induced bistability. Here we subdivide satellite vegetation data into those from human-unaffected areas and those from regions close to human-cultivated zones. Bimodality is found to be almost absent in the unaffected regions, whereas it is significantly enhanced close to cultivated zones. Assuming higher logging rates closer to cultivated zones and spatial diffusion of fire, our spatiotemporal mathematical model reproduces these patterns. Given a gradient of climatic and edaphic factors, rather than bistability there is a predictable spatial boundary, a Maxwell point, that separates regions where forest and savanna states are naturally selected. While bimodality can hence be explained by anthropogenic edge effects and natural spatial heterogeneity, a narrow range of bimodality remaining in the human-unaffected data indicates that there is still bistability, although on smaller scales than claimed previously.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19890064204&hterms=amazon+store&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Damazon%2Bstore','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19890064204&hterms=amazon+store&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Damazon%2Bstore"><span>Calibrating the simple biosphere model for Amazonian tropical forest using field and remote sensing data. I - Average calibration with field data</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sellers, Piers J.; Shuttleworth, W. James; Dorman, Jeff L.; Dalcher, Amnon; Roberts, John M.</p> <p>1989-01-01</p> <p>Using meteorological and hydrological measurements taken in and above the central-Amazon-basin tropical forest, calibration of the Sellers et al. (1986) simple biosphere (SiB) model are described. The SiB model is a one-dimensional soil-vegetation-atmosphere model designed for use within GCMs models, representing the vegetation cover by analogy with processes operating within a single representative plant. The experimental systems and the procedures used to obtain field data are described, together with the specification of the physiological parameterization required to provide an average description of data. It was found that some of the existing literature on stomatal behavior for tropical species is inconsistent with the observed behavior of the complete canopy in Amazonia, and that the rainfall interception store of the canopy is considerably smaller than originally specified in the SiB model.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=283547','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=283547"><span>Rates of species loss from Amazonian forest fragments</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ferraz, Gonçalo; Russell, Gareth J.; Stouffer, Philip C.; Bierregaard, Richard O.; Pimm, Stuart L.; Lovejoy, Thomas E.</p> <p>2003-01-01</p> <p>In the face of worldwide habitat fragmentation, managers need to devise a time frame for action. We ask how fast do understory bird species disappear from experimentally isolated plots in the Biological Dynamics of Forest Fragments Project, central Amazon, Brazil. Our data consist of mist-net records obtained over a period of 13 years in 11 sites of 1, 10, and 100 hectares. The numbers of captures per species per unit time, analyzed under different simplifying assumptions, reveal a set of species-loss curves. From those declining numbers, we derive a scaling rule for the time it takes to lose half the species in a fragment as a function of its area. A 10-fold decrease in the rate of species loss requires a 1,000-fold increase in area. Fragments of 100 hectares lose one half of their species in <15 years, too short a time for implementing conservation measures. PMID:14614134</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26691098','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26691098"><span>Effect of seasonal flooding cycle on litterfall production in alluvial rainforest on the middle Xingu River (Amazon basin, Brazil).</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Camargo, M; Giarrizzo, T; Jesus, A J S</p> <p>2015-08-01</p> <p>The assumption for this study was that litterfall in floodplain environments of the middle Xingu river follows a pattern of seasonal variation. According to this view, litterfall production (total and fractions) was estimated in four alluvial rainforest sites on the middle Xingu River over an annual cycle, and examined the effect of seasonal flooding cycle. The sites included two marginal flooded forests of insular lakes (Ilha Grande and Pimentel) and two flooded forests on the banks of the Xingu itself (Boa Esperança and Arroz Cru). Total litterfall correlated with rainfall and river levels, but whereas the leaf and fruit fractions followed this general pattern, the flower fraction presented an inverse pattern, peaking in the dry season. The litterfall patterns recorded in the present study were consistent with those recorded at other Amazonian sites, and in some other tropical ecosystems.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16606997','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16606997"><span>Wound botulism acquired in the Amazonian rain forest of Ecuador.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Reller, Megan E; Douce, Richard W; Maslanka, Susan E; Torres, Darwin S; Manock, Stephen R; Sobel, Jeremy</p> <p>2006-04-01</p> <p>Wound botulism results from colonization of a contaminated wound by Clostridium botulinum and the anaerobic in situ production of a potent neurotoxin. Between 1943, when wound botulism was first recognized, and 1990, 47 laboratory-confirmed cases, mostly trauma-associated, were reported in the United States. Since 1990, wound botulism associated with injection drug use emerged as the leading cause of wound botulism in the United States; 210 of 217 cases reported to the Centers for Disease Control and Prevention between 1990 and 2002 were associated with drug injection. Despite the worldwide distribution of Clostridium botulinum spores, wound botulism has been reported only twice outside the United States, Europe, and Australia. However, wound botulism may go undiagnosed and untreated in many countries. We report two cases, both with type A toxin, from the Ecuadorian rain forest. Prompt clinical recognition, supportive care, and administration of trivalent equine botulinum antitoxin were life-saving.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.B21G2042F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.B21G2042F"><span>Soil depth influence on Amazonian ecophysiology</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fagerstrom, I.; Baker, I. T.; Gallup, S.; Denning, A. S.</p> <p>2017-12-01</p> <p>Models of land-atmosphere interaction are important for simulating present day weather and critical for predictions of future climate. Land-atmosphere interaction models have become increasingly complex in the last 30 years, leading to the need for further studies examining their intricacies and improvement. This research focuses on the effect of variable soil depth on Amazonian Gross Primary Production (GPP), respiration, and their combination into overall carbon flux. We evaluate a control, which has a universal soil depth of 10 meters, with two experiments of variable soil depths. To conduct this study we ran the 3 models for the period 2000-2012, evaluating similarities and differences between them. We focus on the Amazon rain forest, and compare differences in components of carbon flux. Not surprisingly, we find that the main differences between the models arises in regions where the soil depth is dissimilar between models. However, we did not observe significant differences in GPP between known drought, wet, and average years; interannual variability in carbon dynamics was less than anticipated. We also anticipated that differences between models would be most significant during the dry season, but found discrepancies that persisted through the entire annual cycle.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24130034','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24130034"><span>Biotransformations of terpenes by fungi from Amazonian citrus plants.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Moreno Rueda, Maria Gabriela; Guerrini, Alessandra; Giovannini, Pier Paolo; Medici, Alessandro; Grandini, Alessandro; Sacchetti, Gianni; Pedrini, Paola</p> <p>2013-10-01</p> <p>The biotransformations of (RS)-linalool (1), (S)-citronellal (2), and sabinene (3) with fungi isolated from the epicarp of fruits of Citrus genus of the Amazonian forest (i.e., C. limon, C. aurantifolia, C. aurantium, and C. paradisiaca) are reported. The more active strains have been characterized, and they belong to the genus Penicillium and Fusarium. Different biotransformation products have been obtained depending on fungi and substrates. (RS)-Linalool (1) afforded the (E)- and (Z)-furanlinalool oxides (7 and 8, resp.; 39 and 37% yield, resp.) with Fusarium sp. (1D2), 6-methylhept-5-en-2-one (4; 49%) with F. fujikuroi, and 1-methyl-1-(4-methypentyl)oxiranemethanol (6; 42%) with F. concentricum. (S)-Citronellal (2) gave (S)-citronellol (12; 36-76%) and (S)-citronellic acid (11; 5-43%) with Fusarium species, while diastereoisomeric p-menthane-3,8-diols 13 and 14 (20 and 50% yield, resp.) were obtained as main products with Penicillium paxilli. Finally, both Fusarium species and P. paxilli biotransformed sabinene (3) to give mainly 4-terpineol (19; 23-56%), and (Z)- and (E)-sabinene hydrates (17 (3-21%) and 18 (11-17%), resp.). Copyright © 2013 Verlag Helvetica Chimica Acta AG, Zürich.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26202998','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26202998"><span>The domestication of Amazonia before European conquest.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Clement, Charles R; Denevan, William M; Heckenberger, Michael J; Junqueira, André Braga; Neves, Eduardo G; Teixeira, Wenceslau G; Woods, William I</p> <p>2015-08-07</p> <p>During the twentieth century, Amazonia was widely regarded as relatively pristine nature, little impacted by human history. This view remains popular despite mounting evidence of substantial human influence over millennial scales across the region. Here, we review the evidence of an anthropogenic Amazonia in response to claims of sparse populations across broad portions of the region. Amazonia was a major centre of crop domestication, with at least 83 native species containing populations domesticated to some degree. Plant domestication occurs in domesticated landscapes, including highly modified Amazonian dark earths (ADEs) associated with large settled populations and that may cover greater than 0.1% of the region. Populations and food production expanded rapidly within land management systems in the mid-Holocene, and complex societies expanded in resource-rich areas creating domesticated landscapes with profound impacts on local and regional ecology. ADE food production projections support estimates of at least eight million people in 1492. By this time, highly diverse regional systems had developed across Amazonia where subsistence resources were created with plant and landscape domestication, including earthworks. This review argues that the Amazonian anthrome was no less socio-culturally diverse or populous than other tropical forested areas of the world prior to European conquest. © 2015 The Author(s).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1715107V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1715107V"><span>Interpreting participatory Fuzzy Cognitive Maps as complex networks in the social-ecological systems of the Amazonian forests</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Varela, Consuelo; Tarquis, Ana M.; Blanco-Gutiérrez, Irene; Estebe, Paloma; Toledo, Marisol; Martorano, Lucieta</p> <p>2015-04-01</p> <p>Social-ecological systems are linked complex systems that represent interconnected human and biophysical processes evolving and adapting across temporal and spatial scales. In the real world, social-ecological systems pose substantial challenges for modeling. In this regard, Fuzzy Cognitive Maps (FCMs) have proven to be a useful method for capturing the functioning of this type of systems. FCMs are a semi-quantitative type of cognitive map that represent a system composed of relevant factors and weighted links showing the strength and direction of cause-effects relationships among factors. Therefore, FCMs can be interpreted as complex system structures or complex networks. In this sense, recent research has applied complex network concepts for the analysis of FCMs that represent social-ecological systems. Key to FCM the tool is its potential to allow feedback loops and to include stakeholder knowledge in the construction of the tool. Also, previous research has demonstrated their potential to represent system dynamics and simulate the effects of changes in the system, such as policy interventions. For illustrating this analysis, we have developed a series of participatory FCM for the study of the ecological and human systems related to biodiversity conservation in two case studies of the Amazonian region, the Bolivia lowlands of Guarayos and the Brazil Tapajos National forest. The research is carried out in the context of the EU project ROBIN1 and it is based on the development of a series of stakeholder workshops to analyze the current state of the socio-ecological environment in the Amazonian forest, reflecting conflicts and challenges for biodiversity conservation and human development. Stakeholders included all relevant actors in the local case studies, namely farmers, environmental groups, producer organizations, local and provincial authorities and scientists. In both case studies we illustrate the use of complex networks concepts, such as the adjacency matrix and centrality properties (e.g.: centrality, page-rank, betweenness centrality). Different measures of network centrality evidence that deforestation and loss of biodiversity are the most relevant factors in the FCM of the two case studies analyzed. In both cases agricultural expansion emerges as a key driver of deforestation. The lack of policy coordination and a weak implementation and enforcement are also highly influential factors. The analysis of the system's dynamics suggest that in the case of Bolivia forest fires and deforestation are likely to continue in the immediate future as illegal activities are maintained and poverty increases. In the case of Brazil a decrease in available viable economic activities is driving further deforestation and ecosystem services loss. Overall, the research evidences how using FCMs together with complex network analysis can support policy development by identifying key elements and processes upon which policy makers and institutions can take action. Acknowledgements The authors would like to acknowledge the EU project ROBIN (The Role of Biodiversity in Climate Change Mitigation, from the EC FP7, no 283093) and the Spanish project AL14-PID-12 (Biodiversidad y cambio climático en la Amazonía: Perspectivas socio-económicas y ambientales) of the UPM Latin America Cooperation Program for funding this research.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017Icar..288..120W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017Icar..288..120W"><span>Evidence for stabilization of the ice-cemented cryosphere in earlier martian history: Implications for the current abundance of groundwater at depth on Mars</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Weiss, David K.; Head, James W.</p> <p>2017-05-01</p> <p>The present-day martian mean annual surface temperature is well below freezing at all latitudes; this produces a near-surface portion of the crust that is below the freezing point of water for > 2 consecutive years (defined as permafrost). This permafrost layer (i.e., the cryosphere) is a few to tens of km thick depending on latitude. Below the base of the permafrost (i.e., the cryosphere), groundwater is stable if it exists, and can increase and decrease in abundance as the freezing isotherm rises and falls. Where water is available, ice fills the pore space within the cryosphere; this region is known as the ice-cemented cryosphere (ICC). The potential for a large reservoir of pore ice beneath the surface has been the subject of much discussion: previous studies have demonstrated that the theoretical thickness of the martian cryosphere in the Amazonian period ranges from up to ∼9 km at the equator to ∼10-22 km at the poles. The total thickness of ice that might fill the pore space within the cryosphere (the ICC), however, remains unknown. A class of martian crater, the Hesperian-Amazonian-aged single-layered ejecta crater, is widely accepted as having formed by impact into an ice-cemented target. Although the target structure related to the larger multiple-layered ejecta craters remains uncertain, they have recently been interpreted to be formed by impact crater excavation below the ice-cemented target, and here we tentatively adopt this interpretation in order to infer the thickness of the ice-cemented cryosphere. Our global examination of the excavation depths of these crater populations points to a Hesperian-Amazonian-aged ice-cemented cryosphere that is ∼1.3 km thick at the equator, and ∼2.3 km thick at the poles (corresponding to a global equivalent water layer of ∼200 m assuming ∼20% pore ice at the surface). To explore the implications of this result on the martian climatic and hydrologic evolution, we then assess the surface temperature, atmospheric pressure, obliquity, and surface heat flux conditions under which the downward-propagating cryosphere freezing front matches the inferred ice-cemented cryosphere. The thermal models which can best reproduce the inferred ice-cemented cryosphere occur for obliquities between 25° and 45° and CO2 atmospheric pressures ≤600 mbar, but require increased heat fluxes and surface temperatures/pressures relative to the Amazonian period. Because the inferred ice-cemented cryosphere is much thinner compared with Amazonian-aged cryosphere thermal models, we suggest that the ice-cemented cryosphere ceased growing when it exhausted the underlying groundwater supply (i.e., ICC stabilization) in a more ancient period in Mars geologic history. Our thermal analysis suggests that this ICC stabilization likely occurred sometime before or at ∼3.0-3.3 Ga (during or before the Late Hesperian or Early Amazonian period). If groundwater remained below the ICC during the earlier Late Noachian period, our models predict that mean annual surface temperatures during this time were ≥212-227 K. If the Late Noachian had a pure CO2 atmosphere, this places a minimum bound on the Late Noachian atmospheric pressure of ≥390-850 mbar. These models suggest that deep groundwater is not abundant or does not persist in the subsurface of Mars today, and that diffusive loss of ice from the subsurface has been minimal.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23754540','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23754540"><span>Arbuscular mycorrhizal fungal communities along a pedo-hydrological gradient in a Central Amazonian terra firme forest.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>de Oliveira Freitas, Rejane; Buscardo, Erika; Nagy, Laszlo; dos Santos Maciel, Alex Bruno; Carrenho, Rosilaine; Luizão, Regina C C</p> <p>2014-01-01</p> <p>Little attention has been paid to plant mutualistic interactions in the Amazon rainforest, and the general pattern of occurrence and diversity of arbuscular mycorrhizal fungi (AMF) in these ecosystems is largely unknown. This study investigated AMF communities through their spores in soil in a 'terra firme forest' in Central Amazonia. The contribution played by abiotic factors and plant host species identity in regulating the composition, abundance and diversity of such communities along a topographic gradient with different soils and hydrology was also evaluated. Forty-one spore morphotypes were observed with species belonging to the genera Glomus and Acaulospora, representing 44 % of the total taxa. Soil texture and moisture, together with host identity, were predominant factors responsible for shaping AMF communities along the pedo-hydrological gradient. However, the variability within AMF communities was largely associated with shifts in the relative abundance of spores rather than changes in species composition, confirming that common AMF species are widely distributed in plant communities and all plants recruited into the forest are likely to be exposed to the dominant sporulating AMF species.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19900065052&hterms=nitrous+oxide&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dnitrous%2Boxide','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900065052&hterms=nitrous+oxide&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dnitrous%2Boxide"><span>Sources of variation in nitrous oxide flux from Amazonian ecosystems</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Matson, P. A.; Vitousek, P. M.; Livingston, G. P.; Swanberg, N. A.</p> <p>1990-01-01</p> <p>Nitrous oxide flux and soil nutrient characteristics were measured in three undisturbed tropical ecosystem types, in cleared and burned areas, and in areas of forest converted to pasture near Manaus, Brazil. Nitrogen mineralization, nitrification, and soil nitrogen pools were high in upland forests on clay soils (terra firme) and low in the sand-type and floodplain (varzea) soils. Nitrous oxide flux followed the same pattern, with an average flux of 1.9 ng/sq cm per hr in terra firme, 0.3 in sand types, and 0.1 in varzea. Flux from recently cleared and burned areas did not differ from terra firme forest, but pastures had significantly elevated fluxes (10.3 ng/sq cm per hr). These data were combined with satellite data-based areal estimates of land cover classes to estimate total N2O-N flux from the intensive study area used by the Amazon Boundary Layer Experiment. Total N2O-N flux from the area was 22.9 kg/h; pastures covered 11 percent of the area but accounted for over 40 percent of the flux.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27362236','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27362236"><span>Anthropogenic disturbance in tropical forests can double biodiversity loss from deforestation.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Barlow, Jos; Lennox, Gareth D; Ferreira, Joice; Berenguer, Erika; Lees, Alexander C; Mac Nally, Ralph; Thomson, James R; Ferraz, Silvio Frosini de Barros; Louzada, Julio; Oliveira, Victor Hugo Fonseca; Parry, Luke; Solar, Ricardo Ribeiro de Castro; Vieira, Ima C G; Aragão, Luiz E O C; Begotti, Rodrigo Anzolin; Braga, Rodrigo F; Cardoso, Thiago Moreira; de Oliveira, Raimundo Cosme; Souza, Carlos M; Moura, Nárgila G; Nunes, Sâmia Serra; Siqueira, João Victor; Pardini, Renata; Silveira, Juliana M; Vaz-de-Mello, Fernando Z; Veiga, Ruan Carlo Stulpen; Venturieri, Adriano; Gardner, Toby A</p> <p>2016-07-07</p> <p>Concerted political attention has focused on reducing deforestation, and this remains the cornerstone of most biodiversity conservation strategies. However, maintaining forest cover may not reduce anthropogenic forest disturbances, which are rarely considered in conservation programmes. These disturbances occur both within forests, including selective logging and wildfires, and at the landscape level, through edge, area and isolation effects. Until now, the combined effect of anthropogenic disturbance on the conservation value of remnant primary forests has remained unknown, making it impossible to assess the relative importance of forest disturbance and forest loss. Here we address these knowledge gaps using a large data set of plants, birds and dung beetles (1,538, 460 and 156 species, respectively) sampled in 36 catchments in the Brazilian state of Pará. Catchments retaining more than 69–80% forest cover lost more conservation value from disturbance than from forest loss. For example, a 20% loss of primary forest, the maximum level of deforestation allowed on Amazonian properties under Brazil’s Forest Code, resulted in a 39–54% loss of conservation value: 96–171% more than expected without considering disturbance effects. We extrapolated the disturbance-mediated loss of conservation value throughout Pará, which covers 25% of the Brazilian Amazon. Although disturbed forests retained considerable conservation value compared with deforested areas, the toll of disturbance outside Pará’s strictly protected areas is equivalent to the loss of 92,000–139,000 km2 of primary forest. Even this lowest estimate is greater than the area deforested across the entire Brazilian Amazon between 2006 and 2015 (ref. 10). Species distribution models showed that both landscape and within-forest disturbances contributed to biodiversity loss, with the greatest negative effects on species of high conservation and functional value. These results demonstrate an urgent need for policy interventions that go beyond the maintenance of forest cover to safeguard the hyper-diversity of tropical forest ecosystems.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1917919S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1917919S"><span>Holocene development of Amazonia's oldest peatland</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Swindles, Graeme T.; Morris, Paul J.; Whitney, Bronwen; Galka, Mariusz; Galloway, Jennifer M.; Gallego-Sala, Angela; Macumber, Andrew L.; Mullan, Donal; Smith, Mark W.; Amesbury, Matt; Roland, Thomas; Sanei, Hameed; Patterson, R. Timothy; Parry, Lauren; Charman, Dan J.; Lopez, Omar R.; Valderamma, Elvis; Watson, Elizabeth J.; Lähteenoja, Outi; Baird, Andy J.</p> <p>2017-04-01</p> <p>Peatlands represent some of the most carbon-dense ecosystems of Amazonia. However, little is known about the mechanisms of Amazonian peatland development and their ecohydrological dynamics over time. We present a comprehensive multiproxy dataset from Aucayacu peat dome, the oldest peatland yet discovered in Amazonia (peat initiation occurred between 8.9 and 5.8 ka cal. BP). Our dataset includes analyses of peat physical properties, carbon and nitrogen, humification, organic matter characteristics, macrofossils, pollen, charcoal and testate amoebae. Sedimentological techniques were applied to minerogenic deposits underneath the peatland to understand the nature of the floodplain environment before peat initiation. A transfer function was used to reconstruct past hydrological conditions from subfossil testate amoeba assemblages and carbon accumulation (CA) rates were determined from bulk density and percentage carbon data. A robust chronology was achieved using 210Pb and 14C (14 radiocarbon dates on a 3-m core) determinations, modelled using a Bayesian approach. We used the datasets to investigate the long-term ecohydrological development and controls on carbon accumulation in an Amazonian peat dome. The peatland developed in three distinct stages; (i) abandoned river channel with standing open water and aquatic plants; (ii) inundated forest swamp; and (iii) ombrotrophic bog ( 3.9 ka cal. BP). Local burning occurred twice during the peatland's development as evidenced by macroscopic charcoal but appears to have become more pronounced in the last 100 years. We present a conceptual model of the role of autogenic and allogenic (climate, floodplain) processes on the long-term development of the peatland and the marked variations in carbon accumulation rates over the Holocene. Amazonian peatlands are important carbon stores and ecosystems, and represent important archives of past climatic and ecological information. They should form key foci for conservation efforts.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29785338','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29785338"><span>Coarse- and fine-scale patterns of distribution and habitat selection places an Amazonian floodplain curassow in double jeopardy.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Leite, Gabriel A; Farias, Izeni P; Gonçalves, André L S; Hawes, Joseph E; Peres, Carlos A</p> <p>2018-01-01</p> <p>Patterns of habitat selection are influenced by local productivity, resource availability, and predation risk. Species have taken millions of years to hone the macro- and micro-habitats they occupy, but these may now overlap with contemporary human threats within natural species ranges. Wattled Curassow ( Crax globulosa ), an endemic galliform species of the western Amazon, is threatened by both hunting and habitat loss, and is restricted to white-water floodplain forests of major Amazonian rivers. In this study conducted along the Juruá River, Amazonas, Brazil, we quantified the ranging ecology and fine-scale patterns of habitat selection of the species. We estimated the home range size of C. globulosa using conventional VHF telemetry. To estimate patterns of habitat selection, we used geo-locations of day ranges to examine the extent and intensity of use across the floodplain, which were then compared to a high-resolution flood map of the study area. We captured two females and one male, which we monitored for 13 months between September 2014 and September 2015. Average home range size was 283 ha, based on the 95% aLoCoH estimator. Wattled Curassows selected areas of prolonged flood pulses (six to eight months/year) and had a consistent tendency to be near open water, usually in close proximity to river banks and lakes, especially during the dry season. Amazonian floodplains are densely settled, and the small portions of floodplain habitat used by Wattled Curassows are both the most accessible to hunters and most vulnerable to deforestation. As a result, the geographic and ecological distribution of Wattled Curassows places them at much higher extinction risk at multiple spatial scales, highlighting the need to consider habitat preferences within their conservation strategy.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26700407','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26700407"><span>Large-scale degradation of Amazonian freshwater ecosystems.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Castello, Leandro; Macedo, Marcia N</p> <p>2016-03-01</p> <p>Hydrological connectivity regulates the structure and function of Amazonian freshwater ecosystems and the provisioning of services that sustain local populations. This connectivity is increasingly being disrupted by the construction of dams, mining, land-cover changes, and global climate change. This review analyzes these drivers of degradation, evaluates their impacts on hydrological connectivity, and identifies policy deficiencies that hinder freshwater ecosystem protection. There are 154 large hydroelectric dams in operation today, and 21 dams under construction. The current trajectory of dam construction will leave only three free-flowing tributaries in the next few decades if all 277 planned dams are completed. Land-cover changes driven by mining, dam and road construction, agriculture and cattle ranching have already affected ~20% of the Basin and up to ~50% of riparian forests in some regions. Global climate change will likely exacerbate these impacts by creating warmer and dryer conditions, with less predictable rainfall and more extreme events (e.g., droughts and floods). The resulting hydrological alterations are rapidly degrading freshwater ecosystems, both independently and via complex feedbacks and synergistic interactions. The ecosystem impacts include biodiversity loss, warmer stream temperatures, stronger and more frequent floodplain fires, and changes to biogeochemical cycles, transport of organic and inorganic materials, and freshwater community structure and function. The impacts also include reductions in water quality, fish yields, and availability of water for navigation, power generation, and human use. This degradation of Amazonian freshwater ecosystems cannot be curbed presently because existing policies are inconsistent across the Basin, ignore cumulative effects, and overlook the hydrological connectivity of freshwater ecosystems. Maintaining the integrity of these freshwater ecosystems requires a basinwide research and policy framework to understand and manage hydrological connectivity across multiple spatial scales and jurisdictional boundaries. © 2015 John Wiley & Sons Ltd.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26643123','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26643123"><span>Combining Taxonomic and Functional Approaches to Unravel the Spatial Distribution of an Amazonian Butterfly Community.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Graça, Márlon B; Morais, José W; Franklin, Elizabeth; Pequeno, Pedro A C L; Souza, Jorge L P; Bueno, Anderson Saldanha</p> <p>2016-04-01</p> <p>This study investigated the spatial distribution of an Amazonian fruit-feeding butterfly assemblage by linking species taxonomic and functional approaches. We hypothesized that: 1) vegetation richness (i.e., resources) and abundance of insectivorous birds (i.e., predators) should drive changes in butterfly taxonomic composition, 2) larval diet breadth should decrease with increase of plant species richness, 3) small-sized adults should be favored by higher abundance of birds, and 4) communities with eyespot markings should be able to exploit areas with higher predation pressure. Fruit-feeding butterflies were sampled with bait traps and insect nets across 25 km(2) of an Amazonian ombrophilous forest in Brazil. We measured larval diet breadth, adult body size, and wing marking of all butterflies. Our results showed that plant species richness explained most of the variation in butterfly taxonomic turnover. Also, community average diet breadth decreased with increase of plant species richness, which supports our expectations. In contrast, community average body size increased with the abundance of birds, refuting our hypothesis. We detected no influence of environmental gradients on the occurrence of species with eyespot markings. The association between butterfly taxonomic and functional composition points to a mediator role of the functional traits in the environmental filtering of butterflies. The incorporation of the functional approach into the analyses allowed for the detection of relationships that were not observed using a strictly taxonomic perspective and provided an extra insight into comprehending the potential adaptive strategies of butterflies. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27364995','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27364995"><span>Characterizing the Status (Disturbed, Hybrid or Novel) of Swamp Forest Fragments in a Caribbean Ramsar Wetland: The Impact of Anthropogenic Degradation and Invasive Plant Species.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Prospere, Kurt; McLaren, Kurt P; Wilson, Byron</p> <p>2016-10-01</p> <p>The last remaining Amazonian-type swamp forest fragments in Black River Lower Morass, Jamaica, have been subjected to a myriad of anthropogenic disturbances, compounded by the establishment and spread of several invasive plant species. We established 44 permanent sample plots (covering 3.92 ha) across 10 of these swamp forest fragments and sampled all non-woody plants and all trees ≥2 cm DBH found in the plots. These data were used to (1) identify thresholds of hybridity and novelty, (2) derive several diversity and structural descriptors used to characterize the swamp forest fragments and (3) identify possible indicators of anthropogenic degradation. These were incorporated into a framework and used to determine the status of the swamp forest fragments so that appropriate management and conservation measures can be implemented. We recorded 43 woody plant species (9 endemic, 28 native and 4 non-native) and 21 non-tree species. The composition and structure of all the patches differed significantly due to the impact of the herbaceous invasive plant Alpinia allughas, the presence and diversity of other non-native plants, and differing intensities of anthropogenic disturbance (e.g., burning, cutting and harvesting of non-timber forest products). We ranked forest patches along a continuum representing deviations from a historical proxy (least disturbed) swamp forest to those with dramatically altered structural and floristic attributes (=novel swamp forests). Only one fragment overrun with A. allughas was classified as novel. If effective conservation and management does not come to the BRLM, the remaining swamp forest fragments appear doomed to further degradation and will soon disappear altogether.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EnMan..58..655P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EnMan..58..655P"><span>Characterizing the Status (Disturbed, Hybrid or Novel) of Swamp Forest Fragments in a Caribbean Ramsar Wetland: The Impact of Anthropogenic Degradation and Invasive Plant Species</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prospere, Kurt; McLaren, Kurt P.; Wilson, Byron</p> <p>2016-10-01</p> <p>The last remaining Amazonian-type swamp forest fragments in Black River Lower Morass, Jamaica, have been subjected to a myriad of anthropogenic disturbances, compounded by the establishment and spread of several invasive plant species. We established 44 permanent sample plots (covering 3.92 ha) across 10 of these swamp forest fragments and sampled all non-woody plants and all trees ≥2 cm DBH found in the plots. These data were used to (1) identify thresholds of hybridity and novelty, (2) derive several diversity and structural descriptors used to characterize the swamp forest fragments and (3) identify possible indicators of anthropogenic degradation. These were incorporated into a framework and used to determine the status of the swamp forest fragments so that appropriate management and conservation measures can be implemented. We recorded 43 woody plant species (9 endemic, 28 native and 4 non-native) and 21 non-tree species. The composition and structure of all the patches differed significantly due to the impact of the herbaceous invasive plant Alpinia allughas, the presence and diversity of other non-native plants, and differing intensities of anthropogenic disturbance (e.g., burning, cutting and harvesting of non-timber forest products). We ranked forest patches along a continuum representing deviations from a historical proxy (least disturbed) swamp forest to those with dramatically altered structural and floristic attributes (=novel swamp forests). Only one fragment overrun with A. allughas was classified as novel. If effective conservation and management does not come to the BRLM, the remaining swamp forest fragments appear doomed to further degradation and will soon disappear altogether.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70020184','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70020184"><span>Effect of interannual climate variability on carbon storage in Amazonian ecosystems</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Tian, H.; Melillo, J.M.; Kicklighter, D.W.; McGuire, David A.; Helfrich, J. V. K.; Moore, B.; Vorosmarty, C.J.</p> <p>1998-01-01</p> <p>The Amazon Basin contains almost one-half of the world's undisturbed tropical evergreen forest as well as large areas of tropical savanna. The forests account for about 10 per cent of the world's terrestrial primary productivity and for a similar fraction of the carbon stored in land ecosystems, and short-term field measurements suggest that these ecosystems are globally important carbon sinks. But tropical land ecosystems have experienced substantial interannual climate variability owing to frequent El Nino episodes in recent decades. Of particular importance to climate change policy is how such climate variations, coupled with increases in atmospheric CO2 concentration, affect terrestrial carbon storage. Previous model analyses have demonstrated the importance of temperature in controlling carbon storage. Here we use a transient process-based biogeochemical model of terrestrial ecosystems to investigate interannual variations of carbon storage in undisturbed Amazonian ecosystems in response to climate variability and increasing atmospheric CO2 concentration during the period 1980 to 1994. In El Nino years, which bring hot, dry weather to much of the Amazon region, the ecosystems act as a source of carbon to the atmosphere (up to 0.2 petagrams of carbon in 1987 and 1992). In other years, these ecosystems act as a carbon sink (up to 0.7 Pg C in 1981 and 1993). These fluxes are large; they compare to a 0.3 Pg C per year source to the atmosphere associated with deforestation in the Amazon Basin in the early 1990s. Soil moisture, which is affected by both precipitation and temperature, and which affects both plant and soil processes, appears to be an important control on carbon storage.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20877720','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20877720"><span>Factors affecting the abundance of leaf-litter arthropods in unburned and thrice-burned seasonally-dry Amazonian forests.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Silveira, Juliana M; Barlow, Jos; Louzada, Julio; Moutinho, Paulo</p> <p>2010-09-21</p> <p>Fire is frequently used as a land management tool for cattle ranching and annual crops in the Amazon. However, these maintenance fires often escape into surrounding forests, with potentially severe impacts for forest biodiversity. We examined the effect of experimental fires on leaf-litter arthropod abundance in a seasonally-dry forest in the Brazilian Amazon. The study plots (50 ha each) included a thrice-burned forest and an unburned control forest. Pitfall-trap samples were collected at 160 randomly selected points in both plots, with sampling stratified across four intra-annual replicates across the dry and wet seasons, corresponding to 6, 8, 10 and 12 months after the most recent fire. Arthropods were identified to the level of order (separating Formicidae). In order to better understand the processes that determine arthropod abundance in thrice-burned forests, we measured canopy openness, understory density and litter depth. All arthropod taxa were significantly affected by fire and season. In addition, the interactions between burn treatment and season were highly significant for all taxa but Isoptera. The burned plot was characterized by a more open canopy, lower understory density and shallower litter depth. Hierarchical partitioning revealed that canopy openness was the most important factor explaining arthropod order abundances in the thrice-burned plot, whereas all three environmental variables were significant in the unburned control plot. These results reveal the marked impact of recurrent wildfires and seasonality on litter arthropods in this transitional forest, and demonstrate the overwhelming importance of canopy-openness in driving post-fire arthropod abundance.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2943466','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2943466"><span>Factors Affecting the Abundance of Leaf-Litter Arthropods in Unburned and Thrice-Burned Seasonally-Dry Amazonian Forests</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Silveira, Juliana M.; Barlow, Jos; Louzada, Julio; Moutinho, Paulo</p> <p>2010-01-01</p> <p>Fire is frequently used as a land management tool for cattle ranching and annual crops in the Amazon. However, these maintenance fires often escape into surrounding forests, with potentially severe impacts for forest biodiversity. We examined the effect of experimental fires on leaf-litter arthropod abundance in a seasonally-dry forest in the Brazilian Amazon. The study plots (50 ha each) included a thrice-burned forest and an unburned control forest. Pitfall-trap samples were collected at 160 randomly selected points in both plots, with sampling stratified across four intra-annual replicates across the dry and wet seasons, corresponding to 6, 8, 10 and 12 months after the most recent fire. Arthropods were identified to the level of order (separating Formicidae). In order to better understand the processes that determine arthropod abundance in thrice-burned forests, we measured canopy openness, understory density and litter depth. All arthropod taxa were significantly affected by fire and season. In addition, the interactions between burn treatment and season were highly significant for all taxa but Isoptera. The burned plot was characterized by a more open canopy, lower understory density and shallower litter depth. Hierarchical partitioning revealed that canopy openness was the most important factor explaining arthropod order abundances in the thrice-burned plot, whereas all three environmental variables were significant in the unburned control plot. These results reveal the marked impact of recurrent wildfires and seasonality on litter arthropods in this transitional forest, and demonstrate the overwhelming importance of canopy-openness in driving post-fire arthropod abundance. PMID:20877720</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26552277','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26552277"><span>Structure and composition of altered riparian forests in an agricultural Amazonian landscape.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nagy, R Chelsea; Porder, Stephen; Neill, Christopher; Brando, Paulo; Quintino, Raimundo Mota; do Nascimento, Sebastiâo Aviz</p> <p>2015-09-01</p> <p>Deforestation and fragmentation influence the microclimate, vegetation structure, and composition of remaining patches of tropical forest. In the southern Amazon, at the frontier of cropland expansion, forests are converted and fragmented in a pattern that leaves standing riparian forests whose dimensions are mandated by the Brazilian National Forest Code. These altered riparian forests share many characteristics of well-studied upland forest fragments, but differ because they remain connected to larger areas of forest downstream, and because they may experience wetter soil conditions because reduction of forest cover in the surrounding watershed raises groundwater levels and increases stream runoff. We compared forest regeneration, structure, composition, and diversity in four areas of intact riparian forest and four areas each of narrow, medium, and wide altered riparian forests that have been surrounded by agriculture since the early 1980s. We found that seedling abundance was reduced by as much as 64% and sapling abundance was reduced by as much as 67% in altered compared to intact riparian forests. The most pronounced differences between altered and intact forest occurred near forest edges and within the narrowest sections of altered riparian forests. Woody plant species composition differed and diversity was reduced in altered forests compared to intact riparian forests. However, despite being fragmented for several decades, large woody plant biomass and carbon storage, the number of live or dead large woody plants, mortality rates, and the size distribution of woody plants did not differ significantly between altered and intact riparian forests. Thus, even in these relatively narrow forests with high edge: area ratios, we saw no evidence of the increases in mortality and declines in biomass that have been found in other tropical forest fragment studies. However, because of the changes in both species community and reduced regeneration, it is unclear how long this relative lack of change will be sustained. Additionally, Brazil recently passed a law in their National Forest Code allowing narrower riparian buffers than those studied here in restored areas, which could affect their long-term sustainability.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23028844','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23028844"><span>Determinants of plant community assembly in a mosaic of landscape units in central Amazonia: ecological and phylogenetic perspectives.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Umaña, María Natalia; Norden, Natalia; Cano, Angela; Stevenson, Pablo R</p> <p>2012-01-01</p> <p>The Amazon harbours one of the richest ecosystems on Earth. Such diversity is likely to be promoted by plant specialization, associated with the occurrence of a mosaic of landscape units. Here, we integrate ecological and phylogenetic data at different spatial scales to assess the importance of habitat specialization in driving compositional and phylogenetic variation across the Amazonian forest. To do so, we evaluated patterns of floristic dissimilarity and phylogenetic turnover, habitat association and phylogenetic structure in three different landscape units occurring in terra firme (Hilly and Terrace) and flooded forests (Igapó). We established two 1-ha tree plots in each of these landscape units at the Caparú Biological Station, SW Colombia, and measured edaphic, topographic and light variables. At large spatial scales, terra firme forests exhibited higher levels of species diversity and phylodiversity than flooded forests. These two types of forests showed conspicuous differences in species and phylogenetic composition, suggesting that environmental sorting due to flood is important, and can go beyond the species level. At a local level, landscape units showed floristic divergence, driven both by geographical distance and by edaphic specialization. In terms of phylogenetic structure, Igapó forests showed phylogenetic clustering, whereas Hilly and Terrace forests showed phylogenetic evenness. Within plots, however, local communities did not show any particular trend. Overall, our findings suggest that flooded forests, characterized by stressful environments, impose limits to species occurrence, whereas terra firme forests, more environmentally heterogeneous, are likely to provide a wider range of ecological conditions and therefore to bear higher diversity. Thus, Amazonia should be considered as a mosaic of landscape units, where the strength of habitat association depends upon their environmental properties.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3445462','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3445462"><span>Determinants of Plant Community Assembly in a Mosaic of Landscape Units in Central Amazonia: Ecological and Phylogenetic Perspectives</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Umaña, María Natalia; Norden, Natalia; Cano, Ángela; Stevenson, Pablo R.</p> <p>2012-01-01</p> <p>The Amazon harbours one of the richest ecosystems on Earth. Such diversity is likely to be promoted by plant specialization, associated with the occurrence of a mosaic of landscape units. Here, we integrate ecological and phylogenetic data at different spatial scales to assess the importance of habitat specialization in driving compositional and phylogenetic variation across the Amazonian forest. To do so, we evaluated patterns of floristic dissimilarity and phylogenetic turnover, habitat association and phylogenetic structure in three different landscape units occurring in terra firme (Hilly and Terrace) and flooded forests (Igapó). We established two 1-ha tree plots in each of these landscape units at the Caparú Biological Station, SW Colombia, and measured edaphic, topographic and light variables. At large spatial scales, terra firme forests exhibited higher levels of species diversity and phylodiversity than flooded forests. These two types of forests showed conspicuous differences in species and phylogenetic composition, suggesting that environmental sorting due to flood is important, and can go beyond the species level. At a local level, landscape units showed floristic divergence, driven both by geographical distance and by edaphic specialization. In terms of phylogenetic structure, Igapó forests showed phylogenetic clustering, whereas Hilly and Terrace forests showed phylogenetic evenness. Within plots, however, local communities did not show any particular trend. Overall, our findings suggest that flooded forests, characterized by stressful environments, impose limits to species occurrence, whereas terra firme forests, more environmentally heterogeneous, are likely to provide a wider range of ecological conditions and therefore to bear higher diversity. Thus, Amazonia should be considered as a mosaic of landscape units, where the strength of habitat association depends upon their environmental properties. PMID:23028844</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JGRG..118..400T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JGRG..118..400T"><span>Long-term, high-spatial resolution carbon balance monitoring of the Amazonian frontier: Predisturbance and postdisturbance carbon emissions and uptake</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Toomey, Michael; Roberts, Dar A.; Caviglia-Harris, Jill; Cochrane, Mark A.; Dewes, Candida F.; Harris, Daniel; Numata, Izaya; Sales, Marcio H.; Sills, Erin; Souza, Carlos M.</p> <p>2013-06-01</p> <p>We performed high-spatial and high-temporal resolution modeling of carbon stocks and fluxes in the state of Rondônia, Brazil for the period 1985-2009, using annual Landsat-derived land cover classifications and a modified bookkeeping modeling approach. According to these results, Rondônia contributed 3.5-4% of pantropical humid forest deforestation emissions over this period. Similar to well-known figures reported by the Brazilian Space Agency, we found a decline in deforestation rates since 2006. However, we estimate a lesser decrease, with deforestation rates continuing at levels similar to the early 2000s. Forest carbon stocks declined at an annual rate of 1.51%; emissions from postdisturbance land use nearly equaled those of the initial deforestation events. Carbon uptake by secondary forest was negligible due to limited spatial extent and high turnover rates. Net carbon emissions represented 93% of initial forest carbon stocks, due in part to repeated slash and pasture burnings and secondary forest clearing. We analyzed potential error incurred when spatially aggregating land cover by comparing results based on coarser-resolution (250 m) and full-resolution land cover products. At the coarser resolution, more than 90% of deforestation and secondary forest would be unresolvable, assuming that a 50% change threshold is necessary for detection. Therefore, we strongly suggest the use of Landsat-scale ( 30m) resolution carbon monitoring in tropical regions dominated by nonmechanized, smallholder land use change.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4213623','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4213623"><span>Road networks predict human influence on Amazonian bird communities</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ahmed, Sadia E.; Lees, Alexander C.; Moura, Nárgila G.; Gardner, Toby A.; Barlow, Jos; Ferreira, Joice; Ewers, Robert M.</p> <p>2014-01-01</p> <p>Road building can lead to significant deleterious impacts on biodiversity, varying from direct road-kill mortality and direct habitat loss associated with road construction, to more subtle indirect impacts from edge effects and fragmentation. However, little work has been done to evaluate the specific effects of road networks and biodiversity loss beyond the more generalized effects of habitat loss. Here, we compared forest bird species richness and composition in the municipalities of Santarém and Belterra in Pará state, eastern Brazilian Amazon, with a road network metric called ‘roadless volume (RV)’ at the scale of small hydrological catchments (averaging 3721 ha). We found a significant positive relationship between RV and both forest bird richness and the average number of unique species (species represented by a single record) recorded at each site. Forest bird community composition was also significantly affected by RV. Moreover, there was no significant correlation between RV and forest cover, suggesting that road networks may impact biodiversity independently of changes in forest cover. However, variance partitioning analysis indicated that RV has partially independent and therefore additive effects, suggesting that RV and forest cover are best used in a complementary manner to investigate changes in biodiversity. Road impacts on avian species richness and composition independent of habitat loss may result from road-dependent habitat disturbance and fragmentation effects that are not captured by total percentage habitat cover, such as selective logging, fire, hunting, traffic disturbance, edge effects and road-induced fragmentation. PMID:25274363</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUSMGP43B..03B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUSMGP43B..03B"><span>APW path traced for the Guiana Shield (2070-1960 Ma) and Paleogeographic Implications: Paleomagnetic data from the 1.98-1.96 Ga Surumu Group (Northern Amazonian Craton)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bispo-Santos, F.; Dagrella Filho, M. S.; Reis, N. J.; Trindade, R. I.</p> <p>2013-05-01</p> <p>Definition of continental paleogeography for times prior to formation of Columbia Supercontinent (1900-1850 Ma) is very complex, since amalgamation of some continental blocks of Earth was still in progress, as in the case of Laurentia, Baltica and Amazonian Craton. So, paleogeographic models proposed for this time are still very speculative and/or subjective. The use of the paleomagnetic technique tracing apparent polar wander (APW) paths for the various cratonic blocks can contribute to understand the continental amalgamation and breakup, especially for times where all created oceanic lithosphere was fully consumed. In this study, we present the paleomagnetic data obtained for samples collected from 39 sites from the well-dated 1980-1960 Ma (U-Pb) volcanic rocks belonging to the Surumu Group, cropping out in the northern Roraima State (Guiana Shield, Amazonian Craton). AF and thermal treatment revealed northwestern directions with moderate downward inclinations on samples from 20 out of the 39 analyzed sites. Site mean directions cluster around the mean, Dm = 298.6°; Im = 39.4° (N = 20; α95 = 10.1°), which yielded a key paleomagnetic pole (SG) for the Guiana Shield, located at 234.8°E, 27.4°N (A95 = 9.8°). Magnetic mineralogy experiments show that the magnetization of these rocks, probably of primary origin, is carried by magnetite and/or hematite. The SG pole contributes to a better fit of the APW path traced for Guiana Shield during the Paleoproterozoic (2070-1960 Ma). Comparison with the APW path traced for the West-Africa Craton for the same time interval suggests that these cratonic blocks were linked at 2000-1960 Ma ago, forming a paleogeography in which the Guri (Guiana Shield) and Sassandra (West-Africa Craton) shear zones were aligned as suggested in previous geologic models. KEYWORDS: Paleoproterozoic, Paleomagnetism, APWP, Amazonian Craton, Surumu Group.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JGRG..116.2025L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JGRG..116.2025L"><span>High diversity of tropical peatland ecosystem types in the Pastaza-Marañón basin, Peruvian Amazonia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>LäHteenoja, Outi; Page, Susan</p> <p>2011-06-01</p> <p>Very little information exists on Amazonian peatlands with most studies on tropical peatlands concentrating on Southeast Asia. Here we describe diversity of Amazonian peatland ecosystems and consider its implications for the global diversity of tropical peatland ecosystems. Nine study sites were selected from within the most extensive wetland area of Peruvian Amazonia: the 120,000 km2 Pastaza-Marañón basin. Peat thickness was determined every 500 m from the edge toward the center of each site, and peat samples were collected from two cores per site. Samples from the entire central core and surface samples from the other core were analyzed for nutrient content. Topography of four peat deposits was measured. In order to study differences in vegetation, pixel values were extracted from a satellite image. The surface peat nutrient content of the peatlands varied from very nutrient-rich to nutrient-poor. Two of the peatlands measured for their topography were domed (5.4 and 5.8 m above the stream), one was gently sloping (1.4 m above the stream), and one was flat and occurred behind a 7 m high levee. Five different peatland vegetation types were detected on the basis of pixel values derived from the satellite image. The peat cores had considerable variation in nutrient content and showed different developmental pathways. In summary, the Pastaza-Marañón basin harbors a considerable diversity of previously undescribed peatland ecosystems, representing a gradient from atmosphere-influenced, nutrient-poor ombrotrophic bogs through to river-influenced, nutrient-rich swamps. Their existence affects the habitat diversity, carbon dynamics, and hydrology of the Amazonian lowlands, and they also provide an undisturbed analog for the heavily disturbed peatlands of Southeast Asia. Considering the factors threatening the Amazonian lowlands, there is an urgent need to investigate and conserve these peatland ecosystems, which may in the near future be among the very few undisturbed tropical ombrotrophic bogs remaining in the world.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19900065062&hterms=dry+forest&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Ddry%2Bforest','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900065062&hterms=dry+forest&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Ddry%2Bforest"><span>Ozone measurements in Amazonia - Dry season versus wet season</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kirchhoff, V. W. J. H.; Da Silva, I. M. O.; Browell, Edward V.</p> <p>1990-01-01</p> <p>Recent ozone measurements taken in the Amazonian rain forest environment during the wet season (April-May 1987) are described, revealling new aspects of the regional atmospheric chemistry. The measurements were part of the Amazon Boundary Layer Experiment (ABLE 2B) mission and utilized UV absorption as a measurement technique to obtain surface ozone data; 20 ozonesondes were launched in order to obtain vertical ozone profiles used to describe the upper troposphere and stratosphere. The major differences in comparison to a previous dry season experiment, which found ozone concentrations to be lower in the whole troposphere by nearly a factor of 2, are stressed.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/6677821','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/6677821"><span>A new medicinal plant from Amazonian Ecuador.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>van Asdall, W</p> <p>1983-12-01</p> <p>Dalbergaria tessmanii, a shrub of the Gesneriaceae locally abundant in the tropical forests of Ecuador, is variously ethnomedicinally employed. For example, none of several Shuar (Jívaro) herbal healers know or use it, but the one Shuar Shaman consulted extols its importance in reducing vaginal bleeding. Although Mestizo native consultants from the provincial capital of Morona-Santiago report its use in alleviating heart problems, those from Pastaza Province employ it to reduce menstrual flow. The Lowland Quechua apparently use it for this purpose as well. This plant has apparently not yet been chemically examined. Its reported use in several different cultural context suggest that it should be phytochemically investigated.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28593704','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28593704"><span>Fragmentation increases wind disturbance impacts on forest structure and carbon stocks in a western Amazonian landscape.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Schwartz, Naomi B; Uriarte, María; DeFries, Ruth; Bedka, Kristopher M; Fernandes, Katia; Gutiérrez-Vélez, Victor; Pinedo-Vasquez, Miguel A</p> <p>2017-09-01</p> <p>Tropical second-growth forests could help mitigate climate change, but the degree to which their carbon potential is achieved will depend on exposure to disturbance. Wind disturbance is common in tropical forests, shaping structure, composition, and function, and influencing successional trajectories. However, little is known about the impacts of extreme winds on second-growth forests in fragmented landscapes, though these ecosystems are often located in mosaics of forest, pasture, cropland, and other land cover types. Indirect evidence suggests that fragmentation increases risk of wind damage in tropical forests, but no studies have found such impacts following severe storms. In this study, we ask whether fragmentation and forest type (old vs. second growth) were associated with variation in wind damage after a severe convective storm in a fragmented production landscape in western Amazonia. We applied linear spectral unmixing to Landsat 8 imagery from before and after the storm, and combined it with field observations of damage to map wind effects on forest structure and biomass. We also used Landsat 8 imagery to map land cover with the goals of identifying old- and second-growth forest and characterizing fragmentation. We used these data to assess variation in wind disturbance across 95,596 ha of forest, distributed over 6,110 patches. We find that fragmentation is significantly associated with wind damage, with damage severity higher at forest edges and in edgier, more isolated patches. Damage was also more severe in old-growth than in second-growth forests, but this effect was weaker than that of fragmentation. These results illustrate the importance of considering landscape context in planning tropical forest restoration and natural regeneration projects. Assessments of long-term carbon sequestration potential need to consider spatial variation in disturbance exposure. Where risk of extreme winds is high, minimizing fragmentation and isolation could increase carbon sequestration potential. © 2017 by the Ecological Society of America.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040161151&hterms=landscape&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dlandscape','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040161151&hterms=landscape&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dlandscape"><span>Modeling Forest Understory Fires in an Eastern Amazonian Landscape</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Alencar, A. A. C.; Solorzano, L. A.; Nepstad, D. C.</p> <p>2004-01-01</p> <p>Forest understory fires are an increasingly important cause of forest impoverishment in Ammonia, but little is known of the landscape characteristics and climatic phenomena that determine their occurrence. We developed empirical functions relating the occurrence of understory fires to landscape features near Paragominas, a 35- yr-old ranching and logging center in eastern Ammonia. An historical sequence of maps of forest understory fire was created based on field interviews With local farmers and Landsat TM images. Several landscape features that might explain spatial variations in the occurrence of understory fires were also mapped and co-registered for each of the sample dates, including: forest fragment size and shape, forest impoverishment through logging and understory fires, source of ignition (settlements and charcoal pits), roads, forest edges, and others. The spatial relationship between forest understory fire and each landscape characteristic was tested by regression analyses. Fire probability models were then developed for various combinations of landscape characteristics. The analyses were conducted separately for years of the El Nino Southern Oscillation (ENSO), which are associated with severe drought in eastern Amazonia, and non-ENS0 years. Most (91 %) of the forest area that burned during the 10-yr sequence caught fire during ENSO years, when severe drought may have increased both forest flammability and the escape of agricultural management fires. Forest understory fires were associated with forest edges, as reported in previous studies from Ammonia. But the strongest predictor of forest fire was the percentage of the forest fragment that had been previously logged or burned. Forest fragment size, distance to charcoal pits, distance to agricultural settlement, proximity to forest edge, and distance to roads were also correlated with forest understory fire. Logistic regression models using information on fragment degradation and distance to ignition sources accurately predicted the location of lss than 80% of the forest fires observed during the ENSO event of 1997- 1998. In this Amazon landscape, forest understory fire is a complex function of several variables that influence both the flammability and ignition exposure of the forest.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMPP43C..08T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMPP43C..08T"><span>Mid-Holocene to Present Climate Transition in Tropical South America</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Turcq, B.; Cordeiro, R.; Sifeddine, A.; Braconnot, P.; Dias, P. S.; Costa, R.; Jorgetti, T.</p> <p>2008-12-01</p> <p>The classical illustration of Holocene climate changes in tropical South America is the huge rising of Titicaca lake level from 4400 to 4000 cal BP. Because the Amazon basin is the source of Andean rainfalls we have explored Amazonian data of climate changes during the Holocene to better understand the cause of this abrupt transition. Amazonian data confirm the existence of mid-Holocene dryness: (1) lacustrine level studies show a lower precipitation/evaporation budget than present, with the lowest lake levels between 8500 and 6800 cal BP; (2) although the dominant Holocene vegetation has always been the rainforest in the heart of Amazonia, this forest expanded towards the northwestern and southwestern regions from 6800 to 1550 cal BP, moreover, pioneer elements of the rainforest developed during the mid-Holocene and the best example is those of Cecropia, between 9000 and 5000 cal BP. (3) soil d13C indicates a forest expansion over savannas areas in Roraima (north), Mato Grosso and Rondonia (southwest), during the Holocene. (4) the mid-Holocene (8000- 4000 cal BP) is characterized by repeated occurrences of forest fires, marked by the presence of charcoals in soils and lacustrine sediments. However these different records are not characterized by abrupt transitions at the end of the Middle Holocene in Amazonia. In the Andean records there is a clear north-south shift in the timing of the transition. Analysis of coupled Ocean Atmosphere Model simulations suggest that convection in Amazon basin is directly controlled by insolation leading to an almost linear response of local climate to the global forcing. Differently, in the eastern and south-western regions where the rain is brought by the South American Monsoon, the climate transition appears more abrupt. It may be because the involved climate mechanisms are more complex and depend on Ocean/Atmosphere/Vegetation coupled process (ITCZ position, ZCAS formation, etc.). Tectonic movements or threshold links to lacustrine basin hydrology or to proxy responses to local climate changes must also be carefully taken into account in the identification of abrupt climate changes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JSAES..83..210S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JSAES..83..210S"><span>Recycling of Amazonian detrital zircons in the Mixteco terrane, southern Mexico: Paleogeographic implications during Jurassic-Early Cretaceous and Paleogene times</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Silva-Romo, Gilberto; Mendoza-Rosales, Claudia Cristina; Campos-Madrigal, Emiliano; Morales-Yáñez, Axél; de la Torre-González, Alam Israel; Nápoles-Valenzuela, Juan Ivan</p> <p>2018-04-01</p> <p>In the northeastern Mixteco terrane of southern Mexico, in the Ixcaquixtla-Atzumba region, the recycling of Amazonian detrital zircons records the paleogeography during the Mesozoic period in the context of the breakup of Pangea, a phenomenon that disarticulated the Sanozama-La Mora paleo-river. The clastic units of southern Mexico in the Ayuquila, Otlaltepec and Zapotitlán Mesozoic basins, as well as in the Atzumba Cenozoic basin, are characterized by detrital zircon contents with ages specific to the Amazonian craton, ranging between 3040 and 1278 Ma. The presence of zircons of Amazonian affinity suggests a provenance by recycling from carrier units such as the La Mora Formation or the Ayú Complex. In the area, the Ayú and Acatlán complexes form the Cosoltepec block, a paleogeographic element that during Early Cretaceous time acted as the divide between the slopes of the paleo-Gulf of Mexico and the paleo-Pacific Ocean. The sedimentological characteristics of the Jurassic-Cenozoic clastic successions in the Ixcaquixtla-Atzumba region denote relatively short transport in braided fluvial systems and alluvial fans. In this way, several basins are recognized around the Cosoltepec block. At the southeastern edge of the Cosoltepec block, the Ayuquila and Tecomazúchil formations accumulated in the Ayuquila continental basin on the paleo-Pacific Ocean slope. On the other hand, within the paleo-Gulf of Mexico slope, in the Otlaltepec continental basin, the Piedra Hueca and the Otlaltepec formations accumulated. The upper member of the Santa Lucía Formation accumulated in a transitional environment on the southwestern shoulder of the Zapotitlán basin, as well as on the paleo-Gulf of Mexico slope. In the Ayuquila basin, a marine transgression is recognized that advanced from south to north during the Late Jurassic. At the northeastern edge of the Cosoltepec block, we propose that the Santa Lucía formation attests to a transgression from the paleo-Gulf of Mexico during the Early Cretaceous. Thus, the Cosoltepec block flood occurred during the Albian-Cenomanian, as recognized by the Cipiapa Limestone accumulation. The subsequent uplift of the region and its incorporation into the continental slope is attested by the Atzumba Formation, which offers further evidence of the content of Amazonian detrital zircons recycled from the Ayú Complex. The Atzumba Formation accumulated as alluvial fans during the Paleogene at the hanging wall of the Chazumba fault, which displaced the Cosoltepec block. That is, the detrital zircons in the clastic successions of the Ixcaquixtla-Atzumba region bear indirect testimony to the origin and Amazonian affinity of the Ayú Complex and/or other lithodemes of the Acatlán Complex.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23651778','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23651778"><span>Impact of forested fallows on fertility and mercury content in soils of the Tapajós River region, Brazilian Amazon.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Patry, Cynthia; Davidson, Robert; Lucotte, Marc; Béliveau, Annie</p> <p>2013-08-01</p> <p>Recent research on slash-and-burn agriculture conducted in the Amazonian basin has suggested that soils must be left under forested fallows for at least 10 to 15 years to regain fertility levels comparable to non-disturbed forests in order to allow for short cycle crop cultivation. However, small scale farmers tend nowadays to re-burn secondary forests as soon as after 3 to 5 years, thus could contribute to further reduce soil fertility and could enhance the transfer of mercury (Hg) naturally present in soils of the region towards water courses. The present research project sets out to characterize the impact of forested fallows of differing age and land-use history on soils properties (fertility and Hg contents) in the region of the Tapajós River, an active pioneer front of the Brazilian Amazon. To do this, soil samples in forested fallows of variable age and in control primary forests were retrieved. In general, soil fertility of grouped forested fallows of different ages was similar to that of the primary forests. But when discriminating soils according to their texture, forested fallows on coarse grained soils still had much higher NH4/NO3 ratios, NH4 and Ca contents than primary forests, this even 15 years after burning. The impact of repeated burnings was also assessed. Fallows on coarse grained soils showed an impoverishment for all variables related to fertility when the number of burnings was 5 or more. For fallows on fine grained soils that underwent 5 or more burnings, NO3 contents were low although a cation enrichment was observed. Total soil Hg content was also sensitive to repeated burnings, showing similar losses for forested fallows established on both types of soil. However, Hg linked to coarse particles appeared to migrate back towards fine particles at the surface of coarse grained soils in fallows older than 7 years. Copyright © 2013 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70022461','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70022461"><span>Climatic and biotic controls on annual carbon storage in Amazonian ecosystems</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Tian, H.; Melillo, J.M.; Kicklighter, D.W.; McGuire, A.D.; Helfrich, J.; Moore, B.; Vorosmarty, C.J.</p> <p>2000-01-01</p> <p>1 The role of undisturbed tropical land ecosystems in the global carbon budget is not well understood. It has been suggested that inter-annual climate variability can affect the capacity of these ecosystems to store carbon in the short term. In this paper, we use a transient version of the Terrestrial Ecosystem Model (TEM) to estimate annual carbon storage in undisturbed Amazonian ecosystems during the period 1980-94, and to understand the underlying causes of the year-to-year variations in net carbon storage for this region. 2 We estimate that the total carbon storage in the undisturbed ecosystems of the Amazon Basin in 1980 was 127.6 Pg C, with about 94.3 Pg C in vegetation and 33.3 Pg C in the reactive pool of soil organic carbon. About 83% of the total carbon storage occurred in tropical evergreen forests. Based on our model's results, we estimate that, over the past 15 years, the total carbon storage has increased by 3.1 Pg C (+ 2%), with a 1.9-Pg C (+2%) increase in vegetation carbon and a 1.2-Pg C (+4%) increase in reactive soil organic carbon. The modelled results indicate that the largest relative changes in net carbon storage have occurred in tropical deciduous forests, but that the largest absolute changes in net carbon storage have occurred in the moist and wet forests of the Basin. 3 Our results show that the strength of interannual variations in net carbon storage of undisturbed ecosystems in the Amazon Basin varies from a carbon source of 0.2 Pg C/year to a carbon sink of 0.7 Pg C/year. Precipitation, especially the amount received during the drier months, appears to be a major controller of annual net carbon storage in the Amazon Basin. Our analysis indicates further that changes in precipitation combine with changes in temperature to affect net carbon storage through influencing soil moisture and nutrient availability. 4 On average, our results suggest that the undisturbed Amazonian ecosystems accumulated 0.2 Pg C/year as a result of climate variability and increasing atmospheric CO2 over the study period. This amount is large enough to have compensated for most of the carbon losses associated with tropical deforestation in the Amazon during the same period. 5 Comparisons with empirical data indicate that climate variability and CO2 fertilization explain most of the variation in net carbon storage for the undisturbed ecosystems. Our analyses suggest that assessment of the regional carbon budget in the tropics should be made over at least one cycle of El Nino-Southern Oscillation because of inter-annual climate variability. Our analyses also suggest that proper scaling of the site-specific and sub-annual measurements of carbon fluxes to produce Basin-wide flux estimates must take into account seasonal and spatial variations in net carbon storage.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24372997','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24372997"><span>Identification of areas in Brazil that optimize conservation of forest carbon, jaguars, and biodiversity.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>De Barros, Alan E; MacDonald, Ewan A; Matsumoto, Marcelo H; Paula, Rogério C; Nijhawan, Sahil; Malhi, Y; MacDonald, David W</p> <p>2014-04-01</p> <p>A major question in global environmental policy is whether schemes to reduce carbon pollution through forest management, such as Reducing Emissions from Deforestation and Degradation (REDD+), can also benefit biodiversity conservation in tropical countries. We identified municipalities in Brazil that are priorities for reducing rates of deforestation and thus preserving carbon stocks that are also conservation targets for the endangered jaguar (Panthera onca) and biodiversity in general. Preliminary statistical analysis showed that municipalities with high biodiversity were positively associated with high forest carbon stocks. We used a multicriteria decision analysis to identify municipalities that offered the best opportunities for the conservation of forest carbon stocks and biodiversity conservation under a range of scenarios with different rates of deforestation and carbon values. We further categorized these areas by their representativeness of the entire country (through measures such as percent forest cover) and an indirect measure of cost (number of municipalities). The municipalities that offered optimal co-benefits for forest carbon stocks and conservation were termed REDDspots (n = 159), and their spatial distribution was compared with the distribution of current and proposed REDD projects (n = 135). We defined REDDspots as the municipalities that offer the best opportunities for co-benefits between the conservation of forest carbon stocks, jaguars, and other wildlife. These areas coincided in 25% (n = 40) of municipalities. We identified a further 95 municipalities that may have the greatest potential to develop additional REDD+ projects while also targeting biodiversity conservation. We concluded that REDD+ strategies could be an efficient tool for biodiversity conservation in key locations, especially in Amazonian and Atlantic Forest biomes. ©2013 Society for Conservation Biology.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4371216','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4371216"><span>An overview of malaria transmission from the perspective of Amazon Anopheles vectors</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Pimenta, Paulo FP; Orfano, Alessandra S; Bahia, Ana C; Duarte, Ana PM; Ríos-Velásquez, Claudia M; Melo, Fabrício F; Pessoa, Felipe AC; Oliveira, Giselle A; Campos, Keillen MM; Villegas, Luis Martínez; Rodrigues, Nilton Barnabé; Nacif-Pimenta, Rafael; Simões, Rejane C; Monteiro, Wuelton M; Amino, Rogerio; Traub-Cseko, Yara M; Lima, José BP; Barbosa, Maria GV; Lacerda, Marcus VG; Tadei, Wanderli P; Secundino, Nágila FC</p> <p>2015-01-01</p> <p>In the Americas, areas with a high risk of malaria transmission are mainly located in the Amazon Forest, which extends across nine countries. One keystone step to understanding the Plasmodium life cycle in Anopheles species from the Amazon Region is to obtain experimentally infected mosquito vectors. Several attempts to colonise Ano- pheles species have been conducted, but with only short-lived success or no success at all. In this review, we review the literature on malaria transmission from the perspective of its Amazon vectors. Currently, it is possible to develop experimental Plasmodium vivax infection of the colonised and field-captured vectors in laboratories located close to Amazonian endemic areas. We are also reviewing studies related to the immune response to P. vivax infection of Anopheles aquasalis, a coastal mosquito species. Finally, we discuss the importance of the modulation of Plasmodium infection by the vector microbiota and also consider the anopheline genomes. The establishment of experimental mosquito infections with Plasmodium falciparum, Plasmodium yoelii and Plasmodium berghei parasites that could provide interesting models for studying malaria in the Amazonian scenario is important. Understanding the molecular mechanisms involved in the development of the parasites in New World vectors is crucial in order to better determine the interaction process and vectorial competence. PMID:25742262</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4109186','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4109186"><span>Mosquitoes of eastern Amazonian Ecuador: biodiversity, bionomics and barcodes</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Linton, Yvonne-Marie; Pecor, James E; Porter, Charles H; Mitchell, Luke Brett; Garzón-Moreno, Andrés; Foley, Desmond H; Pecor, David Brooks; Wilkerson, Richard C</p> <p>2013-01-01</p> <p>Two snapshot surveys to establish the diversity and ecological preferences of mosquitoes (Diptera: Culicidae) in the terra firme primary rain forest surrounding the Tiputini Biodiversity Station in the UNESCO Yasuní Biosphere Reserve of eastern Amazonian Ecuador were carried out in November 1998 and May 1999. The mosquito fauna of this region is poorly known; the focus of this study was to obtain high quality link-reared specimens that could be used to unequivocally confirm species level diversity through integrated systematic study of all life stages and DNA sequences. A total of 2,284 specimens were preserved; 1,671 specimens were link-reared with associated immature exuviae, all but 108 of which are slide mounted. This study identified 68 unique taxa belonging to 17 genera and 27 subgenera. Of these, 12 are new to science and 37 comprise new country records. DNA barcodes [658-bp of the mtDNA cytochrome c oxidase ( COI ) I gene] are presented for 58 individuals representing 20 species and nine genera. DNA barcoding proved useful in uncovering and confirming new species and we advocate an integrated systematics approach to biodiversity studies in future. Associated bionomics of all species collected are discussed. An updated systematic checklist of the mosquitoes of Ecuador (n = 179) is presented for the first time in 60 years. PMID:24473809</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25742262','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25742262"><span>An overview of malaria transmission from the perspective of Amazon Anopheles vectors.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pimenta, Paulo F P; Orfano, Alessandra S; Bahia, Ana C; Duarte, Ana P M; Ríos-Velásquez, Claudia M; Melo, Fabrício F; Pessoa, Felipe A C; Oliveira, Giselle A; Campos, Keillen M M; Villegas, Luis Martínez; Rodrigues, Nilton Barnabé; Nacif-Pimenta, Rafael; Simões, Rejane C; Monteiro, Wuelton M; Amino, Rogerio; Traub-Cseko, Yara M; Lima, José B P; Barbosa, Maria G V; Lacerda, Marcus V G</p> <p>2015-02-01</p> <p>In the Americas, areas with a high risk of malaria transmission are mainly located in the Amazon Forest, which extends across nine countries. One keystone step to understanding the Plasmodium life cycle in Anopheles species from the Amazon Region is to obtain experimentally infected mosquito vectors. Several attempts to colonise Anopheles species have been conducted, but with only short-lived success or no success at all. In this review, we review the literature on malaria transmission from the perspective of its Amazon vectors. Currently, it is possible to develop experimental Plasmodium vivax infection of the colonised and field-captured vectors in laboratories located close to Amazonian endemic areas. We are also reviewing studies related to the immune response to P. vivax infection of Anopheles aquasalis, a coastal mosquito species. Finally, we discuss the importance of the modulation of Plasmodium infection by the vector microbiota and also consider the anopheline genomes. The establishment of experimental mosquito infections with Plasmodium falciparum, Plasmodium yoelii and Plasmodium berghei parasites that could provide interesting models for studying malaria in the Amazonian scenario is important. Understanding the molecular mechanisms involved in the development of the parasites in New World vectors is crucial in order to better determine the interaction process and vectorial competence.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NatCC...5..656B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NatCC...5..656B"><span>Projected strengthening of Amazonian dry season by constrained climate model simulations</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Boisier, Juan P.; Ciais, Philippe; Ducharne, Agnès; Guimberteau, Matthieu</p> <p>2015-07-01</p> <p>The vulnerability of Amazonian rainforest, and the ecological services it provides, depends on an adequate supply of dry-season water, either as precipitation or stored soil moisture. How the rain-bearing South American monsoon will evolve across the twenty-first century is thus a question of major interest. Extensive savanization, with its loss of forest carbon stock and uptake capacity, is an extreme although very uncertain scenario. We show that the contrasting rainfall projections simulated for Amazonia by 36 global climate models (GCMs) can be reproduced with empirical precipitation models, calibrated with historical GCM data as functions of the large-scale circulation. A set of these simple models was therefore calibrated with observations and used to constrain the GCM simulations. In agreement with the current hydrologic trends, the resulting projection towards the end of the twenty-first century is for a strengthening of the monsoon seasonal cycle, and a dry-season lengthening in southern Amazonia. With this approach, the increase in the area subjected to lengthy--savannah-prone--dry seasons is substantially larger than the GCM-simulated one. Our results confirm the dominant picture shown by the state-of-the-art GCMs, but suggest that the `model democracy' view of these impacts can be significantly underestimated.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.3321D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.3321D"><span>Multiple constraint modeling of nutrient cycling stoichiometry following forest clearing and pasture abandonment in the Eastern Amazon</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Davidson, Eric; Nifong, Rachel</p> <p>2017-04-01</p> <p>While deforestation has declined since its peak, land-use change continues to modify Amazonian landscapes. The responses and feedbacks of biogeochemical cycles to these changes play an important role in determining possible future trajectories of ecosystem function and for land stewardship through effects on rates of secondary forest regrowth, soil emissions of greenhouse gases, inputs of nutrients to groundwater and streamwater, and nutrient management in agroecosystems. Here we present a new synthetic analyses of data from the NASA-supported LBA-ECO project and others datasets on nutrient cycling in cattle pastures, secondary forests, and mature forests at Paragominas, Pará, Brazil. We have developed a stoichiometric model relating C-N-P interactions during original forest clearing, extensive and intensive pasture management, and secondary forest regrowth, constrained by multiple observations of ecosystem stocks and fluxes in each land use. While P is conservatively cycled in all land uses, we demonstrate that pyrolyzation of N during pasture formation and during additional burns for pasture management depletes available-N pools, consistent with observations of lower rates of N leaching and trace gas emission and consistent with secondary forest growth responses to experimental N amendments. The soils store large stocks of N and P, and our parameterization of available forms of these nutrients for steady-state dynamics in the mature forest yield reasonable estimates of net N and P mineralization available for grasses and secondary forest species at rates consistent with observed biomass accumulation and productivity in these modified ecosystems. Because grasses and forests have much different demands for N relative to P, the land use has important biogeochemical impacts. The model demonstrates the need for periodic P inputs for sustainable pasture management and for a period of significant biological N fixation for early-to-mid-successional secondary forest regrowth. The model framework illustrates the relative magnitudes of changing stocks and flows of nutrients and attendant ecosystem functions through the phases of land use change experienced in eastern Amazonia.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3507040','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3507040"><span>Production of Alkaline Cellulase by Fungi Isolated from an Undisturbed Rain Forest of Peru</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Vega, Karin; Villena, Gretty K.; Sarmiento, Victor H.; Ludeña, Yvette; Vera, Nadia; Gutiérrez-Correa, Marcel</p> <p>2012-01-01</p> <p>Alkaline cellulase producing fungi were isolated from soils of an undisturbed rain forest of Peru. The soil dilution plate method was used for the enumeration and isolation of fast growing cellulolytic fungi on an enriched selective medium. Eleven out of 50 different morphological colonies were finally selected by using the plate clearing assay with CMC as substrate at different pH values. All 11 strains produced cellulases in liquid culture with activities at alkaline pH values without an apparent decrease of them indicating that they are true alkaline cellulase producers. Aspergillus sp. LM-HP32, Penicillium sp. LM-HP33, and Penicillium sp. LM-HP37 were the best producers of FP cellulase (>3 U mL−1) with higher specific productivities (>30 U g−1 h−1). Three strains have been found suitable for developing processes for alkaline cellulase production. Soils from Amazonian rain forests are good sources of industrial fungi with particular characteristics. The results of the present study are of commercial and biological interest. Alkaline cellulases may be used in the polishing and washing of denim processing of the textile industry. PMID:23213539</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27757421','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27757421"><span>Empty forest or empty rivers? A century of commercial hunting in Amazonia.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Antunes, André P; Fewster, Rachel M; Venticinque, Eduardo M; Peres, Carlos A; Levi, Taal; Rohe, Fabio; Shepard, Glenn H</p> <p>2016-10-01</p> <p>The Amazon basin is the largest and most species-rich tropical forest and river system in the world, playing a pivotal role in global climate regulation and harboring hundreds of traditional and indigenous cultures. It is a matter of intense debate whether the ecosystem is threatened by hunting practices, whereby an "empty forest" loses critical ecological functions. Strikingly, no previous study has examined Amazonian ecosystem resilience through the perspective of the massive 20th century international trade in furs and skins. We present the first historical account of the scale and impacts of this trade and show that whereas aquatic species suffered basin-wide population collapse, terrestrial species did not. We link this differential resilience to the persistence of adequate spatial refuges for terrestrial species, enabling populations to be sustained through source-sink dynamics, contrasting with unremitting hunting pressure on more accessible aquatic habitats. Our findings attest the high vulnerability of aquatic fauna to unregulated hunting, particularly during years of severe drought. We propose that the relative resilience of terrestrial species suggests a marked opportunity for managing, rather than criminalizing, contemporary traditional subsistence hunting in Amazonia, through both the engagement of local people in community-based comanagement programs and science-led conservation governance.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.B22A..03F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.B22A..03F"><span>On the use of through-fall exclusion experiments to filter model hypotheses.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fisher, R.</p> <p>2015-12-01</p> <p>One key threat to the continued existence of large tropical forest carbon reservoirs is the increasing severity of drought across Amazonian forests, observed both in climate model predictions, in recent extreme drought events and in the more chronic lengthening of the dry season of South Eastern Amazonia. Model comprehension of these systems is in it's infancy, particularly with regard to the sensitivities of model output to the representation of hydraulic strategies in tropical forest systems. Here we use data from the ongoing 14 year old Caxiuana through-fall exclusion experiment, in Eastern Brazil, to filter a set of representations of the costs and benefits of alternative hydraulic strategies. In representations where there is a high resource cost to hydraulic resilience, the trait filtering CLM4.5(ED) model selects vegetation types that are sensitive to drought. Conversely, where drought tolerance is inexpensive, a more robust ecosystem emerges from the vegetation dynamic prediction. Thus, there is an impact of trait trade-off relationships on rainforest drought tolerance. It is possible to constrain the more realistic scenarios using outputs from the drought experiments. Better prediction would likely result from a more comprehensive understanding of the costs and benefits of alternative plant strategies.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.B31C1138H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.B31C1138H"><span>Improving the Amazonian Hydrologic Cycle in a Coupled Land-Atmosphere, Single Column Model</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Harper, A. B.; Denning, S.; Baker, I.; Prihodko, L.; Branson, M.</p> <p>2006-12-01</p> <p>We have coupled a land-surface model, the Simple Biosphere Model (SiB3), to a single column of the Colorado State University General Circulation Model (CSU-GCM) in the Amazon River Basin. This is a preliminary step in the broader goal of improved simulation of Basin-wide hydrology. A previous version of the coupled model (SiB2) showed drought and catastrophic dieback of the Amazon rain forest. SiB3 includes updated soil hydrology and root physiology. Our test area for the coupled single column model is near Santarem, Brazil, where measurements from the km 83 flux tower in the Tapajos National Forest can be used to evaluate model output. The model was run for 2001 using NCEP2 Reanalysis as driver data. Preliminary results show that the updated biosphere model coupled to the GCM produces improved simulations of the seasonal cycle of surface water balance and precipitation. Comparisons of the diurnal and seasonal cycles of surface fluxes are also being made.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27224473','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27224473"><span>Density and Biomass Estimates by Removal for an Amazonian Crocodilian, Paleosuchus palpebrosus.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Campos, Zilca; Magnusson, William E</p> <p>2016-01-01</p> <p>Direct counts of crocodilians are rarely feasible and it is difficult to meet the assumptions of mark-recapture methods for most species in most habitats. Catch-out experiments are also usually not logistically or morally justifiable because it would be necessary to destroy the habitat in order to be confident that most individuals had been captured. We took advantage of the draining and filling of a large area of flooded forest during the building of the Santo Antônio dam on the Madeira River to obtain accurate estimates of the density and biomass of Paleosuchus palpebrosus. The density, 28.4 non-hatchling individuals per km2, is one of the highest reported for any crocodilian, except for species that are temporarily concentrated in small areas during dry-season drought. The biomass estimate of 63.15 kg*km-2 is higher than that for most or even all mammalian carnivores in tropical forest. P. palpebrosus may be one of the World´s most abundant crocodilians.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=social+AND+media+AND+tourism&id=ED517597','ERIC'); return false;" href="https://eric.ed.gov/?q=social+AND+media+AND+tourism&id=ED517597"><span>Voices of Contact: Politics of Language in Urban Amazonian Ecuador</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Wroblewski, Michael</p> <p>2010-01-01</p> <p>This dissertation is a study of diverse linguistic resources and contentious identity politics among indigenous Amazonian Kichwas in the city of Tena, Ecuador. Tena is a rapidly developing Amazonian provincial capital city with a long history of interethnic and interlinguistic contact. In recent decades, the course of indigenous Kichwa identity…</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=deforestation&pg=6&id=ED325047','ERIC'); return false;" href="https://eric.ed.gov/?q=deforestation&pg=6&id=ED325047"><span>The Mission of the Amazonian Universities in Economic Development and Environmental Preservation.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Lourenco, Jose Seixas</p> <p></p> <p>The Association of Amazonian Universities (UNAMAZ) was created in September 1987 and is involved in a collective effort to find ways to promote the Amazonian region's nonpredatory development, recognizing its limitations and taking into account its potential. With deforestation taking place at ever-increasing speed, it has become necessary to…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007WRR....43.8432B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007WRR....43.8432B"><span>Modeling the effects of throughfall reduction on soil water content in a Brazilian Oxisol under a moist tropical forest</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Belk, Elizabeth L.; Markewitz, Daniel; Rasmussen, Todd C.; Carvalho, Eduardo J. Maklouf; Nepstad, Daniel C.; Davidson, Eric A.</p> <p>2007-08-01</p> <p>Access to water reserves in deep soil during drought periods determines whether or not the tropical moist forests of Amazonia will be buffered from the deleterious effects of water deficits. Changing climatic conditions are predicted to increase periods of drought in Amazonian forests and may lead to increased tree mortality, changes in forest composition, or greater susceptibility to fire. A throughfall reduction experiment has been established in the Tapajós National Forest of east-central Amazonia (Brazil) to test the potential effects of severe water stress during prolonged droughts. Using time domain reflectometry observations of water contents from this experiment, we have developed a dynamic, one-dimensional, vertical flow model to enhance our understanding of hydrologic processes within these tall-stature forests on well-drained, upland, deep Oxisols and to simulate changes in the distribution of soil water. Simulations using 960 days of data accurately captured mild soil water depletion near the surface after the first treatment year and decreasing soil moisture at depth during the second treatment year. The model is sensitive to the water retention and unsaturated flow equation parameters, specifically the van Genuchten parameters θs, θr, and n, but less sensitive to Ks and α. The low root-mean-square error between observed and predicted volumetric soil water content suggests that this vertical flow model captures the most important hydrologic processes in the upper landscape position of this study site. The model indicates that present rates of evapotranspiration within the exclusion plot have been sustained at the expense of soil water storage.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26101423','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26101423"><span>The Tetramerium lineage (Acanthaceae: Justicieae) does not support the Pleistocene Arc hypothesis for South American seasonally dry forests.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Côrtes, Ana Luiza A; Rapini, Alessandro; Daniel, Thomas F</p> <p>2015-06-01</p> <p>The Tetramerium lineage (Acanthaceae) presents a striking ecological structuring in South America, with groups concentrated in moist forests or in seasonally dry forests. In this study, we investigate the circumscription and relationships of the South American genera as a basis for better understanding historic interactions between dry and moist biomes in the Neotropics. We dated the ancestral distribution of the Tetramerium lineage based on one nuclear and four plastid DNA regions. Maximum parsimony, maximum likelihood, and Bayesian inference analyses were performed for this study using 104 terminals. Phylogenetic divergences were dated using a relaxed molecular clock approach and ancestral distributions obtained from dispersal-vicariance analyses. The genera Pachystachys, Schaueria, and Thyrsacanthus are nonmonophyletic. A dry forest lineage dispersed from North America to South America and reached the southwestern part of the continent between the end of the Miocene and beginning of the Pleistocene. This period coincides with the segregation between Amazonian and Atlantic moist forests that established the geographic structure currently found in the group. The South American genera Pachystachys, Schaueria, and Thyrsacanthus need to be recircumscribed. The congruence among biogeographical events found for the Tetramerium lineage suggests that the dry forest centers currently dispersed throughout South America are relatively old remnants, probably isolated since the Neogene, much earlier than the Last Glacial Maximum postulated by the Pleistocene Arc hypothesis. In addition to exploring the Pleistocene Arc hypothesis, this research also informs evolution in a lineage with numerous geographically restricted and threatened species. © 2015 Botanical Society of America, Inc.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25274363','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25274363"><span>Road networks predict human influence on Amazonian bird communities.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ahmed, Sadia E; Lees, Alexander C; Moura, Nárgila G; Gardner, Toby A; Barlow, Jos; Ferreira, Joice; Ewers, Robert M</p> <p>2014-11-22</p> <p>Road building can lead to significant deleterious impacts on biodiversity, varying from direct road-kill mortality and direct habitat loss associated with road construction, to more subtle indirect impacts from edge effects and fragmentation. However, little work has been done to evaluate the specific effects of road networks and biodiversity loss beyond the more generalized effects of habitat loss. Here, we compared forest bird species richness and composition in the municipalities of Santarém and Belterra in Pará state, eastern Brazilian Amazon, with a road network metric called 'roadless volume (RV)' at the scale of small hydrological catchments (averaging 3721 ha). We found a significant positive relationship between RV and both forest bird richness and the average number of unique species (species represented by a single record) recorded at each site. Forest bird community composition was also significantly affected by RV. Moreover, there was no significant correlation between RV and forest cover, suggesting that road networks may impact biodiversity independently of changes in forest cover. However, variance partitioning analysis indicated that RV has partially independent and therefore additive effects, suggesting that RV and forest cover are best used in a complementary manner to investigate changes in biodiversity. Road impacts on avian species richness and composition independent of habitat loss may result from road-dependent habitat disturbance and fragmentation effects that are not captured by total percentage habitat cover, such as selective logging, fire, hunting, traffic disturbance, edge effects and road-induced fragmentation. © 2014 The Author(s) Published by the Royal Society. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GBioC..30...18A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GBioC..30...18A"><span>Changing Amazon biomass and the role of atmospheric CO2 concentration, climate, and land use</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Almeida Castanho, Andrea D.; Galbraith, David; Zhang, Ke; Coe, Michael T.; Costa, Marcos H.; Moorcroft, Paul</p> <p>2016-01-01</p> <p>The Amazon tropical evergreen forest is an important component of the global carbon budget. Its forest floristic composition, structure, and function are sensitive to changes in climate, atmospheric composition, and land use. In this study biomass and productivity simulated by three dynamic global vegetation models (Integrated Biosphere Simulator, Ecosystem Demography Biosphere Model, and Joint UK Land Environment Simulator) for the period 1970-2008 are compared with observations from forest plots (Rede Amazónica de Inventarios Forestales). The spatial variability in biomass and productivity simulated by the DGVMs is low in comparison to the field observations in part because of poor representation of the heterogeneity of vegetation traits within the models. We find that over the last four decades the CO2 fertilization effect dominates a long-term increase in simulated biomass in undisturbed Amazonian forests, while land use change in the south and southeastern Amazonia dominates a reduction in Amazon aboveground biomass, of similar magnitude to the CO2 biomass gain. Climate extremes exert a strong effect on the observed biomass on short time scales, but the models are incapable of reproducing the observed impacts of extreme drought on forest biomass. We find that future improvements in the accuracy of DGVM predictions will require improved representation of four key elements: (1) spatially variable plant traits, (2) soil and nutrients mediated processes, (3) extreme event mortality, and (4) sensitivity to climatic variability. Finally, continued long-term observations and ecosystem-scale experiments (e.g. Free-Air CO2 Enrichment experiments) are essential for a better understanding of the changing dynamics of tropical forests.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JPRS..119..361M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JPRS..119..361M"><span>Floristic composition and across-track reflectance gradient in Landsat images over Amazonian forests</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Muro, Javier; doninck, Jasper Van; Tuomisto, Hanna; Higgins, Mark A.; Moulatlet, Gabriel M.; Ruokolainen, Kalle</p> <p>2016-09-01</p> <p>Remotely sensed image interpretation or classification of tropical forests can be severely hampered by the effects of the bidirectional reflection distribution function (BRDF). Even for narrow swath sensors like Landsat TM/ETM+, the influence of reflectance anisotropy can be sufficiently strong to introduce a cross-track reflectance gradient. If the BRDF could be assumed to be linear for the limited swath of Landsat, it would be possible to remove this gradient during image preprocessing using a simple empirical method. However, the existence of natural gradients in reflectance caused by spatial variation in floristic composition of the forest can restrict the applicability of such simple corrections. Here we use floristic information over Peruvian and Brazilian Amazonia acquired through field surveys, complemented with information from geological maps, to investigate the interaction of real floristic gradients and the effect of reflectance anisotropy on the observed reflectances in Landsat data. In addition, we test the assumption of linearity of the BRDF for a limited swath width, and whether different primary non-inundated forest types are characterized by different magnitudes of the directional reflectance gradient. Our results show that a linear function is adequate to empirically correct for view angle effects, and that the magnitude of the across-track reflectance gradient is independent of floristic composition in the non-inundated forests we studied. This makes a routine correction of view angle effects possible. However, floristic variation complicates the issue, because different forest types have different mean reflectances. This must be taken into account when deriving the correction function in order to avoid eliminating natural gradients.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27113632','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27113632"><span>Medicinal Bioprospecting of the Amazon Rainforest: A Modern Eldorado?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Skirycz, Aleksandra; Kierszniowska, Sylwia; Méret, Michaël; Willmitzer, Lothar; Tzotzos, George</p> <p>2016-10-01</p> <p>Ignorant of the New World, Europeans believed in El Dorado, a hidden city of immense wealth in gold. Many consider the Amazonian forest to be a medicinal treasure chest and potentially the largest drug dispensary in the world. Yet, the quest to obtain drugs from indigenous tropical plants remains elusive. Here, we assess the potential of new technologies to tap into the metabolic diversity of tropical plants. We also consider how regulations affect access to plant resources. We conclude that, although the road to this medicinal El Dorado may be long and arduous, many other smaller but still valuable finds are hidden along the way. Copyright © 2016 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940020388','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940020388"><span>Human impacts on soil carbon dynamics of deep-rooted Amazonian forests</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nepstad, Daniel C.; Stone, Thomas A.; Davidson, Eric A.</p> <p>1994-01-01</p> <p>Deforestation and logging degrade more forest in eastern and southern Amazonia than in any other region of the world. This forest alteration affects regional hydrology and the global carbon cycle, but our current understanding of these effects is limited by incomplete knowledge of tropical forest ecosystems. It is widely agreed that roots are concentrated near the soil surface in moist tropical forests, but this generalization incorrectly implies that deep roots are unimportant in water and C budgets. Our results indicate that half of the closed-canopy forests of Brazilian Amazonic occur where rainfall is highly seasonal, and these forests rely on deeply penetrating roots to extract soil water. Pasture vegetation extracts less water from deep soil than the forest it replaces, thus increasing rates of drainage and decreasing rates of evapotranspiration. Deep roots are also a source of modern carbon deep in the soil. The soils of the eastern Amazon contain more carbon below 1 m depth than is present in above-ground biomass. As much as 25 percent of this deep soil C could have annual to decadal turnover times and may be lost to the atmosphere following deforestation. We compared the importance of deep roots in a mature, evergreen forest with an adjacent man-made pasture, the most common type of vegetation on deforested land in Amazonia. The study site is near the town of Paragominas, in the Brazilian state of Para, with a seasonal rainfall pattern and deeply-weathered, kaolinitic soils that are typical for large portions of Amazonia. Root distribution, soil water extraction, and soil carbon dynamics were studied using deep auger holes and shafts in each ecosystem, and the phenology and water status of the leaf canopies were measured. We estimated the geographical distribution of deeply-rooting forests using satellite imagery, rainfall data, and field measurements.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040161150&hterms=legal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dlegal','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040161150&hterms=legal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dlegal"><span>The Net Carbon Flux due to Deforestation and Forest Re-Growth in the Brazilian Amazon: Analysis using a Process-Based Model</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hirsch, A. I.; Little, W. S.; Houghton, R. A.; Scott, N. A.; White, J. D.</p> <p>2004-01-01</p> <p>We developed a process-based model of forest growth, carbon cycling, and land cover dynamics named CARLUC (for CARbon and Land Use Change) to estimate the size of terrestrial carbon pools in terra firme (non-flooded) forests across the Brazilian Legal Amazon and the net flux of carbon resulting from forest disturbance and forest recovery from disturbance. Our goal in building the model was to construct a relatively simple ecosystem model that would respond to soil and climatic heterogeneity that allows us to study of the impact of Amazonian deforestation, selective logging, and accidental fire on the global carbon cycle. This paper focuses on the net flux caused by deforestation and forest re-growth over the period from 1970-1998. We calculate that the net flux to the atmosphere during this period reached a maximum of approx. 0.35 PgC/yr (1PgC = 1 x 10(exp I5) gC) in 1990, with a cumulative release of approx. 7 PgC from 1970- 1998. The net flux is higher than predicted by an earlier study by a total of 1 PgC over the period 1989-1 998 mainly because CARLUC predicts relatively high mature forest carbon storage compared to the datasets used in the earlier study. Incorporating the dynamics of litter and soil carbon pools into the model increases the cumulative net flux by approx. 1 PgC from 1970-1998, while different assumptions about land cover dynamics only caused small changes. The uncertainty of the net flux, calculated with a Monte-Carlo approach, is roughly 35% of the mean value (1 SD).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24416414','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24416414"><span>Oil road effects on the anuran community of a high canopy tank bromeliad (Aechmea zebrina) in the upper Amazon basin, Ecuador.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>McCracken, Shawn F; Forstner, Michael R J</p> <p>2014-01-01</p> <p>Tropical forest canopies are among the most species-rich terrestrial habitats on earth and one of the remaining relatively unexplored biotic frontiers. Epiphytic bromeliads provide microhabitat for a high diversity of organisms in tropical forest canopies and are considered a keystone resource. A number of amphibians inhabit these phytotelmata, yet their ecological role and status in forest canopies remains unknown. For this study, anurans were collected from an upper canopy tank bromeliad (Aechmea zebrina) at ∼20-45 m (x¯ = 33 m) above the forest floor. Bromeliads were sampled from trees located near trails in undisturbed primary rainforest and oil access roads in the Yasuní Biosphere Reserve of Amazonian Ecuador. We collected 95 anurans representing 10 species from 160 bromeliads in 32 trees. We used generalized linear mixed models to assess the effects of disturbance and habitat factors on the occupancy and abundance of anurans collected. Bromeliads in forest along oil roads had a lower occupancy and abundance of anurans than those in undisturbed forest, a somewhat unexpected result due to the intactness and quality of forest adjacent to the roads. Recorded habitat variables had no relationship with occupancy or abundance of anurans, and did not differ significantly between treatments. Our findings reveal that even the minimal footprint of natural resource extraction operations, primarily roads, in rainforest environments can have significant negative impacts on the unique upper canopy anuran community. Based on these results, we recommend that natural resource development treat rainforest habitat as an offshore system where roads are not used, employ industry best practice guidelines, and current access roads be protected from colonization and further deforestation.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3885719','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3885719"><span>Oil Road Effects on the Anuran Community of a High Canopy Tank Bromeliad (Aechmea zebrina) in the Upper Amazon Basin, Ecuador</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>McCracken, Shawn F.; Forstner, Michael R. J.</p> <p>2014-01-01</p> <p>Tropical forest canopies are among the most species-rich terrestrial habitats on earth and one of the remaining relatively unexplored biotic frontiers. Epiphytic bromeliads provide microhabitat for a high diversity of organisms in tropical forest canopies and are considered a keystone resource. A number of amphibians inhabit these phytotelmata, yet their ecological role and status in forest canopies remains unknown. For this study, anurans were collected from an upper canopy tank bromeliad (Aechmea zebrina) at ∼20–45 m (x¯ = 33 m) above the forest floor. Bromeliads were sampled from trees located near trails in undisturbed primary rainforest and oil access roads in the Yasuní Biosphere Reserve of Amazonian Ecuador. We collected 95 anurans representing 10 species from 160 bromeliads in 32 trees. We used generalized linear mixed models to assess the effects of disturbance and habitat factors on the occupancy and abundance of anurans collected. Bromeliads in forest along oil roads had a lower occupancy and abundance of anurans than those in undisturbed forest, a somewhat unexpected result due to the intactness and quality of forest adjacent to the roads. Recorded habitat variables had no relationship with occupancy or abundance of anurans, and did not differ significantly between treatments. Our findings reveal that even the minimal footprint of natural resource extraction operations, primarily roads, in rainforest environments can have significant negative impacts on the unique upper canopy anuran community. Based on these results, we recommend that natural resource development treat rainforest habitat as an offshore system where roads are not used, employ industry best practice guidelines, and current access roads be protected from colonization and further deforestation. PMID:24416414</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/29987','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/29987"><span>Factors influencing spatial pattern in tropical forest clearance and stand age: Implications for carbon storage and species diversity.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>E. H. Helmer; Thomas J. Brandeis; Ariel E. Lugo; Todd Kennaway</p> <p>2008-01-01</p> <p>Little is known about the tropical forests that undergo clearing as urban/built-up and other developed lands spread. This study uses remote sensing-based maps of Puerto Rico, multinomial logit models and forest inventory data to explain patterns of forest age and the age of forests cleared for land development and assess their implications for forest carbon storage and...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=indigenous&pg=5&id=EJ1168355','ERIC'); return false;" href="https://eric.ed.gov/?q=indigenous&pg=5&id=EJ1168355"><span>Higher Education and Urban Migration for Community Resilience: Indigenous Amazonian Youth Promoting Place-Based Livelihoods and Identities in Peru</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Steele, Diana</p> <p>2018-01-01</p> <p>This paper offers an ethnographic analysis of indigenous Peruvian Amazonian youth pursuing higher education through urban migration to contribute to the resilience of their communities, place-based livelihoods, and indigenous Amazonian identities. Youth and their communities promoted education and migration as powerful tools in the context of…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26097240','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26097240"><span>Shifts in indigenous culture relate to forest tree diversity: a case study from the Tsimane', Bolivian Amazon.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Guèze, Maximilien; Luz, Ana Catarina; Paneque-Gálvez, Jaime; Macía, Manuel J; Orta-Martínez, Martí; Pino, Joan; Reyes-García, Victoria</p> <p>2015-06-01</p> <p>Understanding how indigenous peoples' management practices relate to biological diversity requires addressing contemporary changes in indigenous peoples' way of life. This study explores the association between cultural change among a Bolivian Amazonian indigenous group, the Tsimane', and tree diversity in forests surrounding their villages. We interviewed 86 informants in six villages about their level of attachment to traditional Tsimane' values, our proxy for cultural change. We estimated tree diversity (Fisher's Alpha index) by inventorying trees in 48 0.1-ha plots in old-growth forests distributed in the territory of the same villages. We used multivariate models to assess the relation between cultural change and alpha tree diversity. Cultural change was associated with alpha tree diversity and the relation showed an inverted U-shape, thus suggesting that tree alpha diversity peaked in villages undergoing intermediate cultural change. Although the results do not allow for testing the direction of the relation, we propose that cultural change relates to tree diversity through the changes in practices and behaviors that affect the traditional ecological knowledge of Tsimane' communities; further research is needed to determine the causality. Our results also find support in the intermediate disturbance hypothesis, and suggest that indigenous management can be seen as an intermediate form of anthropogenic disturbance affecting forest communities in a subtle, non-destructive way.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4471141','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4471141"><span>Shifts in indigenous culture relate to forest tree diversity: a case study from the Tsimane’, Bolivian Amazon</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Guèze, Maximilien; Luz, Ana Catarina; Paneque-Gálvez, Jaime; Macía, Manuel J.; Orta-Martínez, Martí; Pino, Joan; Reyes-García, Victoria</p> <p>2015-01-01</p> <p>Understanding how indigenous peoples’ management practices relate to biological diversity requires addressing contemporary changes in indigenous peoples’ way of life. This study explores the association between cultural change among a Bolivian Amazonian indigenous group, the Tsimane’, and tree diversity in forests surrounding their villages. We interviewed 86 informants in six villages about their level of attachment to traditional Tsimane’ values, our proxy for cultural change. We estimated tree diversity (Fisher’s Alpha index) by inventorying trees in 48 0.1-ha plots in old-growth forests distributed in the territory of the same villages. We used multivariate models to assess the relation between cultural change and alpha tree diversity. Cultural change was associated with alpha tree diversity and the relation showed an inverted U-shape, thus suggesting that tree alpha diversity peaked in villages undergoing intermediate cultural change. Although the results do not allow for testing the direction of the relation, we propose that cultural change relates to tree diversity through the changes in practices and behaviors that affect the traditional ecological knowledge of Tsimane’ communities; further research is needed to determine the causality. Our results also find support in the intermediate disturbance hypothesis, and suggest that indigenous management can be seen as an intermediate form of anthropogenic disturbance affecting forest communities in a subtle, non-destructive way. PMID:26097240</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25234242','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25234242"><span>Molecular phylogeny, species limits, and biogeography of the Brazilian endemic lizard genus Enyalius (Squamata: Leiosauridae): an example of the historical relationship between Atlantic Forests and Amazonia.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rodrigues, Miguel Trefaut; Bertolotto, Carolina Elena Viña; Amaro, Renata Cecília; Yonenaga-Yassuda, Yatiyo; Freire, Eliza Maria Xavier; Pellegrino, Katia Cristina Machado</p> <p>2014-12-01</p> <p>The endemic Brazilian Enyalius encompasses a diverse group of forest lizards with most species restricted to the Atlantic Forest (AF). Their taxonomy is problematic due to extensive variation in color pattern and external morphology. We present the first phylogenetic hypothesis for the genus based on 2102 bp of the mtDNA (cyt-b, ND4, and 16S) and nuclear (c-mos) regions, uncovering all previously admitted taxa (9 spp). Different methods of tree reconstruction were explored with Urostrophus vautieri, Anisolepis grilli and A. longicauda as outgroups. The monophyly of Enyalius and its split into two deeply divergent clades (late Oligocene and early Miocene) is strongly supported. Clade A assembles most lineages restricted to south and southeastern Brazil, and within it Enyalius brasiliensis is polyphyletic; herein full species status of E. brasiliensis and E. boulengeri is resurrected. Clade B unites the Amazonian E. leechii as sister-group to a major clade containing E. bilineatus as sister-group to all remaining species from northeastern Brazil. We detected unrecognized diversity in several populations suggesting putative species. Biogeographical analyses indicate that Enyalius keeps fidelity to shadowed forests, with few cases of dispersal into open regions. Ancient dispersal into the Amazon from an AF ancestor may have occurred through northeastern Brazil. Copyright © 2014 Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26174960','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26174960"><span>Responses of Aquatic Saproxylic Macroinvertebrates to Reduced-Impact Logging in Central Amazonia.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Roque, F O; Escarpinati, S C; Valente-Neto, F; Hamada, N</p> <p>2015-08-01</p> <p>Reduced-impact logging (RIL) is an alternative land use because it reduces damage to forest cover in comparison with clear-cut practices. However, management practices adopted in RIL can affect wood availability and, consequently, fauna associated with dead wood during part of their life cycle (saproxylic). In this study, we evaluated whether aquatic saproxylic macroinvertebrates are affected by reduced-impact logging in Central Amazonia. We selected six streams in areas under reduced-impacted logging and six in primary forest areas and collected submerged woody debris. We did not find any differences in water pH, conductivity, and wood availability between reduced-impacted forest and primary forest streams. We found 248 saproxylic aquatic macroinvertebrates belonging to 37 taxa. We found five wood specialist (Dryops, Lutrochus, Stenochironomus, Oukuriella, and Endotribelos) and 32 generalists, totalling 98 and 150 individuals, respectively. In general, our results show that reduced-impact logging does not affect richness, abundance, and composition of saproxylic macroinvertebrates. The main explanation for this pattern is that management practices do not change important macroinvertebrate niche dimensions, including wood availability and the water's chemical and physical variables. Thus, controlled logging, such as applied in the area of the Central Amazonian streams studied, opens a new prospect for insect conservation and commercial exploitation of wood, which is not possible when clear-cut practices are adopted.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/14180','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/14180"><span>Seventy Years of Forest Change in the Northern Great Lakes Region, USA</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Lisa A. Schulte; Thomas R. Crow; Dave Cleland</p> <p>2003-01-01</p> <p>The rates and magnitudes of forest change have important social and economic implications. We address facets of change associated with 20th century recovery of the U.S. Lake States (Michigan, Wisconsin, and Minnesota) forests from the Great Cutover, and discuss ecological and socioeconomic implications for future forest resources.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A31A0004C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A31A0004C"><span>The impact of anthropogenic emissions on the otherwise pristine Amazonian rainforest: Insights on aerosol dynamics as observed during GoAmazon2014/5</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carbone, S.; Ferreira De Brito, J.; Cirino, G. G.; Rizzo, L. V.; Holanda, B. A.; Barbosa, H. M.; Ditas, F.; Pöhlker, C.; Chi, X.; Krüger, M. L.; Moran, D.; Saturno, J.; Andreae, M. O.; de Sá, S. S.; Liu, Y.; Martin, S. T.; Souza, R. A. F. D.; Wang, J.; Palm, B. B.; Jimenez, J. L.; Artaxo, P.</p> <p>2015-12-01</p> <p>The Amazon Basin during the wet season has one of the lowest aerosol concentrations worldwide, with air masses with negligible human impact covering thousands of kilometers of pristine forest. The natural environment is strongly modified near urbanized areas, in particular Manaus, a city of nearly two million people. This unique location provides the ideal laboratory to study isolated urban emissions as well the pristine environment by perturbing it in a relatively known fashion. The GoAmazon2014/5 experiment was designed with these questions in mind, combining remote sensing, in situ, and airborne measurements. This manuscript describes the measurements taken at the T0 site, upwind of Manaus, (the Amazonian Tall Tower Observatory, ATTO site), at the T2 site, near Manaus, frequently impacted by relatively fresh emissions from the city and at T3, 60 km downwind of Manaus. This work relates the aerosol dynamics of the mixture of anthropogenic emissions from Manaus and the biogenic air masses, and how it evolves from T2 to T3 under different atmospheric conditions. Focus is on the aerosol size distribution, supported by aerosol mass spectrometry and gas-phase composition, in particular at the T2 site. At T0, the aerosol number concentration has been observed to increase from an average of 380 cm-3 to 1750 cm-3 from the wet to the dry season. The mean geometric diameter increased as well, from 95 nm to 145 nm. Interestingly, at the T2 site no significant difference was observed in number concentration between wet and dry seasons (approximately 4300 cm-3) with an average diameter of 60 nm during the former and 97 nm in the latter. Such measurements provide a unique dataset to understand the aerosol life cycle and the impact of urban emissions in the heart of the Amazon Forest.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18267905','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18267905"><span>Towards quantifying uncertainty in predictions of Amazon 'dieback'.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Huntingford, Chris; Fisher, Rosie A; Mercado, Lina; Booth, Ben B B; Sitch, Stephen; Harris, Phil P; Cox, Peter M; Jones, Chris D; Betts, Richard A; Malhi, Yadvinder; Harris, Glen R; Collins, Mat; Moorcroft, Paul</p> <p>2008-05-27</p> <p>Simulations with the Hadley Centre general circulation model (HadCM3), including carbon cycle model and forced by a 'business-as-usual' emissions scenario, predict a rapid loss of Amazonian rainforest from the middle of this century onwards. The robustness of this projection to both uncertainty in physical climate drivers and the formulation of the land surface scheme is investigated. We analyse how the modelled vegetation cover in Amazonia responds to (i) uncertainty in the parameters specified in the atmosphere component of HadCM3 and their associated influence on predicted surface climate. We then enhance the land surface description and (ii) implement a multilayer canopy light interception model and compare with the simple 'big-leaf' approach used in the original simulations. Finally, (iii) we investigate the effect of changing the method of simulating vegetation dynamics from an area-based model (TRIFFID) to a more complex size- and age-structured approximation of an individual-based model (ecosystem demography). We find that the loss of Amazonian rainforest is robust across the climate uncertainty explored by perturbed physics simulations covering a wide range of global climate sensitivity. The introduction of the refined light interception model leads to an increase in simulated gross plant carbon uptake for the present day, but, with altered respiration, the net effect is a decrease in net primary productivity. However, this does not significantly affect the carbon loss from vegetation and soil as a consequence of future simulated depletion in soil moisture; the Amazon forest is still lost. The introduction of the more sophisticated dynamic vegetation model reduces but does not halt the rate of forest dieback. The potential for human-induced climate change to trigger the loss of Amazon rainforest appears robust within the context of the uncertainties explored in this paper. Some further uncertainties should be explored, particularly with respect to the representation of rooting depth.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMEP31B0812Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMEP31B0812Z"><span>Alluvial deposits and plant distribution in an Amazonian lowland megafan</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zani, H.; Rossetti, D.; Cremon; Cohen, M.; Pessenda, L. C.</p> <p>2012-12-01</p> <p>A large volume of sandy alluvial deposits (> 1000 km2) characterizes a flat wetland in northern Amazonia. These have been recently described as the sedimentary record of a megafan system, which have a distinct triangular shape produced by highly migratory distributary rivers. The vegetation map suggests that this megafan is dominated by open vegetation in sharp contact with the surround rainforest. Understanding the relationship between geomorphological processes and vegetation distribution is crucial to decipher and conserve the biodiversity in this Amazonian ecosystem. In this study we interpret plant dynamics over time, and investigate its potential control by sedimentary processes during landscape evolution. The study area is located in the Viruá National Park. Two field campaigns were undertaken in the dry seasons of 2010 and 2011 and the sampling sites were selected by combining accessibility and representativeness. Vegetation contrasts were recorded along a transect in the medial section of the Viruá megafan. Due to the absence of outcrops, samples were extracted using a core device, which allowed sampling up to a depth of 7.5 m. All cores were opened and described in the field, with 5 cm3 samples collected at 20 cm intervals. The δ13C of organic matter was used as a proxy to distinguish between C3 and C4 plant communities. The chronology was established based on radiocarbon dating. The results suggest that the cores from forested areas show the most depleted values of δ13C, ranging from -32.16 to -27.28‰. The δ13C curve in these areas displays typical C3 land plant values for the entire record, which covers most of the Holocene. This finding indicates that either the vegetation remained stable over time or the sites were dominated by aquatic environments with freshwater plants before forest establishment. The cores from the open vegetation areas show a progressive upward enrichment in δ13C values, which range from -28.50 to -19.59‰. This trend is more pronounced after de mid-Holocene, suggesting that the open vegetation, represented mostly by C4 land plants, evolved only more recently. Based on our isotope data, a model is proposed taking into account the influence of sedimentary dynamics on the modern pattern of plan distribution. The establishment of open vegetation occurred at different times depending on location over the megafan area, varying from around 3,000 to 6,400 cal yrs BP. As sedimentation took place, areas located far from the surrounding rainforest were prone to inputs of organic matter derived from open vegetation, whereas the contribution of organic matter derived from arboreous vegetation increases toward the areas located closer to the rainforest. In general, open vegetation is constrained to depositional sites that remained active until relatively recent Holocene times, while surrounding areas with a relatively older geological history are covered by dense forest. The results presented here consist in a striking example of the influence of sedimentary processes during the Late Pleistocene-Holocene on the development of modern plants of this Amazonian lowland.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27039519','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27039519"><span>How livestock and flooding mediate the ecological integrity of working forests in Amazon River floodplains.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lucas, Christine M; Sheikh, Pervaze; Gagnon, Paul R; Mcgrath, David G</p> <p>2016-01-01</p> <p>The contribution of working forests to tropical conservation and development depends upon the maintenance of ecological integrity under ongoing land use. Assessment of ecological integrity requires an understanding of the structure, composition, and function and major drivers that govern their variability. Working forests in tropical river floodplains provide many goods and services, yet the data on the ecological processes that sustain these services is scant. In flooded forests of riverside Amazonian communities, we established 46 0.1-ha plots varying in flood duration, use by cattle and water buffalo, and time since agricultural abandonment (30-90 yr). We monitored three aspects of ecological integrity (stand structure, species composition, and dynamics of trees and seedlings) to evaluate the impacts of different trajectories of livestock activity (alleviation, stasis, and intensification) over nine years. Negative effects of livestock intensification were solely evident in the forest understory, and plots alleviated from past heavy disturbance increased in seedling density but had higher abundance of thorny species than plots maintaining low activity. Stand structure, dynamics, and tree species composition were strongly influenced by the natural pulse of seasonal floods, such that the defining characteristics of integrity were dependent upon flood duration (3-200 d). Forests with prolonged floods ≥ 140 d had not only lower species richness but also lower rates of recruitment and species turnover relative to forests with short floods <70 d. Overall, the combined effects of livestock intensification and prolonged flooding hindered forest regeneration, but overall forest integrity was largely related to the hydrological regime and age. Given this disjunction between factors mediating canopy and understory integrity, we present a subset of metrics for regeneration and recruitment to distinguish forest condition by livestock trajectory. Although our study design includes confounded factors that preclude a definitive assessment of the major drivers of ecological change, we provide much-needed data on the regrowth of a critical but poorly studied ecosystem. In addition to its emphasis on the dynamics of tropical wetland forests undergoing anthropogenic and environmental change, our case study is an important example for how to assess of ecological integrity in working forests of tropical ecosystems.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4450676','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4450676"><span>Preliminary Biological Studies on Larvae and Adult Anopheles Mosquitoes (Diptera: Culicidae) in Miraflores, a Malaria Endemic Locality in Guaviare Department, Amazonian Colombia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>JIMÉNEZ, IRENE P.; CONN, JAN E.; BROCHERO, HELENA</p> <p>2015-01-01</p> <p>In the malaria endemic municipality of Miraflores in southeastern Amazonian Colombia, several aspects of the biology of local Anopheles species were investigated to supplement the limited entomological surveillance information available and to provide baseline data for malaria prevention and vector control. Anopheles darlingi Root, 1926 was the most abundant species (95.6%), followed by Anopheles braziliensis (Chagas) (3.6%) and Anopheles oswaldoi s.l. (Peryassu) (0.7%). During the dry season, exophagic activity was prevalent only between 1800–2100 hours; after this (2100–0600 hours) only endophagy was encountered. In contrast, during the rainy season, both endophagy and exophagy occurred throughout the collection period. The human biting rate for An. darlingi was 8.6. This species was positive for Plasmodium vivax VK210 with a sporozoite rate = 0.13 (1/788). Breeding sites corresponded to stream (n = 7), flooded excavations (n = 4), flooded forest (n = 1), wetlands (n = 2), and an abandoned water reservoir (n = 1). An. darlingi predominated in these sites in both seasons. Based on these data, An. darlingi is the main local malaria vector, and we recommend that local prevention and control efforts focus on strengthening entomological surveillance to determine potential changes of species biting behavior and time to reduce human–vector interactions. PMID:25276930</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29457226','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29457226"><span>Coordination and trade-offs among hydraulic safety, efficiency and drought avoidance traits in Amazonian rainforest canopy tree species.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Santiago, Louis S; De Guzman, Mark E; Baraloto, Christopher; Vogenberg, Jacob E; Brodie, Max; Hérault, Bruno; Fortunel, Claire; Bonal, Damien</p> <p>2018-05-01</p> <p>Predicting responses of tropical forests to climate change-type drought is challenging because of high species diversity. Detailed characterization of tropical tree hydraulic physiology is necessary to evaluate community drought vulnerability and improve model parameterization. Here, we measured xylem hydraulic conductivity (hydraulic efficiency), xylem vulnerability curves (hydraulic safety), sapwood pressure-volume curves (drought avoidance) and wood density on emergent branches of 14 common species of Eastern Amazonian canopy trees in Paracou, French Guiana across species with the densest and lightest wood in the plot. Our objectives were to evaluate relationships among hydraulic traits to identify strategies and test the ability of easy-to-measure traits as proxies for hard-to-measure hydraulic traits. Xylem efficiency was related to capacitance, sapwood water content and turgor loss point, and other drought avoidance traits, but not to xylem safety (P 50 ). Wood density was correlated (r = -0.57 to -0.97) with sapwood pressure-volume traits, forming an axis of hydraulic strategy variation. In contrast to drier sites where hydraulic safety plays a greater role, tropical trees in this humid tropical site varied along an axis with low wood density, high xylem efficiency and high capacitance at one end of the spectrum, and high wood density and low turgor loss point at the other. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3023789','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3023789"><span>Use and knowledge of the razor-billed curassow pauxi tuberosa (spix, 1825) (galliformes, cracidae) by a riverine community of the oriental amazonia, brazil</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2011-01-01</p> <p>In the Amazonian basin, the human populations that traditionally inhabit the forest use its natural resources in various ways. One example is the local fauna which, among several other uses, is an important source of protein. The general aim of our study was to investigate the importance of hunting to the lives of the Amazonian riverine communities and to identify the multiple uses and knowledge about the hunted animals. In this article we focused the study on the razor-billed curassow Pauxi tuberosa, a Cracidae of significant value to the studied community. The investigation was conducted in the "Riozinho do Anfrísio Extractive Reserve", a Brazilian Conservation Unit located at the Altamira municipality, in the state of Pará. We used an ethnoecological approach, which included participant observation and semi-structured interviews. Our results show that the razor-billed curassow is used by the "Riozinho do Anfrísio" local population mainly as food, but it also fulfils secondary functions, with the feathers being used as a domestic tool and as magic-religious symbol, some organs as traditional medicine, and some chicks even being raised as pets. Our study also revealed that the traditional ecological knowledge of the riverines about their environment is considerably large, and that the local biodiversity provides various ecosystem services. PMID:21194497</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GMD.....8.1097R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GMD.....8.1097R"><span>Modelling climate change responses in tropical forests: similar productivity estimates across five models, but different mechanisms and responses</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rowland, L.; Harper, A.; Christoffersen, B. O.; Galbraith, D. R.; Imbuzeiro, H. M. A.; Powell, T. L.; Doughty, C.; Levine, N. M.; Malhi, Y.; Saleska, S. R.; Moorcroft, P. R.; Meir, P.; Williams, M.</p> <p>2015-04-01</p> <p>Accurately predicting the response of Amazonia to climate change is important for predicting climate change across the globe. Changes in multiple climatic factors simultaneously result in complex non-linear ecosystem responses, which are difficult to predict using vegetation models. Using leaf- and canopy-scale observations, this study evaluated the capability of five vegetation models (Community Land Model version 3.5 coupled to the Dynamic Global Vegetation model - CLM3.5-DGVM; Ecosystem Demography model version 2 - ED2; the Joint UK Land Environment Simulator version 2.1 - JULES; Simple Biosphere model version 3 - SiB3; and the soil-plant-atmosphere model - SPA) to simulate the responses of leaf- and canopy-scale productivity to changes in temperature and drought in an Amazonian forest. The models did not agree as to whether gross primary productivity (GPP) was more sensitive to changes in temperature or precipitation, but all the models were consistent with the prediction that GPP would be higher if tropical forests were 5 °C cooler than current ambient temperatures. There was greater model-data consistency in the response of net ecosystem exchange (NEE) to changes in temperature than in the response to temperature by net photosynthesis (An), stomatal conductance (gs) and leaf area index (LAI). Modelled canopy-scale fluxes are calculated by scaling leaf-scale fluxes using LAI. At the leaf-scale, the models did not agree on the temperature or magnitude of the optimum points of An, Vcmax or gs, and model variation in these parameters was compensated for by variations in the absolute magnitude of simulated LAI and how it altered with temperature. Across the models, there was, however, consistency in two leaf-scale responses: (1) change in An with temperature was more closely linked to stomatal behaviour than biochemical processes; and (2) intrinsic water use efficiency (IWUE) increased with temperature, especially when combined with drought. These results suggest that even up to fairly extreme temperature increases from ambient levels (+6 °C), simulated photosynthesis becomes increasingly sensitive to gs and remains less sensitive to biochemical changes. To improve the reliability of simulations of the response of Amazonian rainforest to climate change, the mechanistic underpinnings of vegetation models need to be validated at both leaf- and canopy-scales to improve accuracy and consistency in the quantification of processes within and across an ecosystem.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4375856','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4375856"><span>A Miocene hyperdiverse crocodylian community reveals peculiar trophic dynamics in proto-Amazonian mega-wetlands</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Salas-Gismondi, Rodolfo; Flynn, John J.; Baby, Patrice; Tejada-Lara, Julia V.; Wesselingh, Frank P.; Antoine, Pierre-Olivier</p> <p>2015-01-01</p> <p>Amazonia contains one of the world's richest biotas, but origins of this diversity remain obscure. Onset of the Amazon River drainage at approximately 10.5 Ma represented a major shift in Neotropical ecosystems, and proto-Amazonian biotas just prior to this pivotal episode are integral to understanding origins of Amazonian biodiversity, yet vertebrate fossil evidence is extraordinarily rare. Two new species-rich bonebeds from late Middle Miocene proto-Amazonian deposits of northeastern Peru document the same hyperdiverse assemblage of seven co-occurring crocodylian species. Besides the large-bodied Purussaurus and Mourasuchus, all other crocodylians are new taxa, including a stem caiman—Gnatusuchus pebasensis—bearing a massive shovel-shaped mandible, procumbent anterior and globular posterior teeth, and a mammal-like diastema. This unusual species is an extreme exemplar of a radiation of small caimans with crushing dentitions recording peculiar feeding strategies correlated with a peak in proto-Amazonian molluscan diversity and abundance. These faunas evolved within dysoxic marshes and swamps of the long-lived Pebas Mega-Wetland System and declined with inception of the transcontinental Amazon drainage, favouring diversification of longirostrine crocodylians and more modern generalist-feeding caimans. The rise and demise of distinctive, highly productive aquatic ecosystems substantially influenced evolution of Amazonian biodiversity hotspots of crocodylians and other organisms throughout the Neogene. PMID:25716785</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17354429','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17354429"><span>Diversity of the ground-dwelling ant fauna (Hymenoptera: Formicidae) of a moist, Montane forest of the semi-arid Brazilian "Nordeste".</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hites, N L; Mourão, M A N; Araújo, F O; Melo, M V C; de Biseau, J C; Quinet, Y</p> <p>2005-01-01</p> <p>Although the so called "green islands" of the semi-arid Brazilian "Nordeste" are economically, socially, and ecologically important. relatively little is known about their biodiversity. We present the results of the first survey of the ground-dwelling ant fauna of a secondary forest in the Serra de Baturité (4 degrees 05'-4 degrees 40' S / 38 degrees 30'-39 degrees 10' W), among the biggest of the moist, montane forests of the state of Ceará, Brazil. From February to March 2001, samples were taken every 50 m along twelve 200 m transects, each separated from the others by at least 50 m and cut on either side of a recreational trail. Where possible, two transects were cut from the same starting point on the trail, one on either side. At each sample site two methods were used, as recommended in the ALL. protocol: a pitfall trap and the treatment of 1 m2 of leaf litter with the Winkler extractor. The myrmecofauna of the Serra de Baturité is quite diverse: individuals from 72 species, 23 genera, and six subfamilies were collected. The observed patterns of specific richness show the same tendencies noted in other tropical regions, particularly the frequency of capture distribution with many rare and few abundant species. Differences with the Atlantic and Amazonian forests were also observed, especially the relative importance of the Ponerinac and Formicinae subfamilies, indicating a possible influence of the surrounding "caatinga" (savanna-like ecosystem) on the myrmecofauna of the moist, montane forest.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70032428','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70032428"><span>Pollen-based biome reconstructions for Latin America at 0, 6000 and 18 000 radiocarbon years</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Marchant, R.; Harrison, S.P.; Hooghiemstra, H.; Markgraf, Vera; Van Boxel, J. H.; Ager, T.; Almeida, L.; Anderson, R.; Baied, C.; Behling, H.; Berrio, J.C.; Burbridge, R.; Bjorck, S.; Byrne, R.; Bush, M.B.; Cleef, A.M.; Duivenvoorden, J.F.; Flenley, J.R.; De Oliveira, P.; Van Geel, B.; Graf, K.J.; Gosling, W.D.; Harbele, S.; Van Der Hammen, T.; Hansen, B.C.S.; Horn, S.P.; Islebe, G.A.; Kuhry, P.; Ledru, M.</p> <p>2009-01-01</p> <p>The biomisation method is used to reconstruct Latin American vegetation at 6000±500 and 18 000±1000 radiocarbon years before present (14C yr BP) from pollen data. Tests using modern pollen data from 381 samples derived from 287 locations broadly reproduce potential natural vegetation. The strong temperature gradient associated with the Andes is recorded by a transition from high altitude cool grass/shrubland and cool mixed forest to mid-altitude cool temperate rain forest, to tropical dry, seasonal and rain forest at low altitudes. Reconstructed biomes from a number of sites do not match the potential vegetation due to local factors such as human impact, methodological artefacts and mechanisms of pollen representivity of the parent vegetation. At 6000±500 14C yr BP 255 samples are analysed from 127 sites. Differences between the modern and the 6000±500 14C yr BP reconstruction are comparatively small. Patterns of change relative to the modern reconstruction are mainly to biomes characteristic of drier climate in the north of the region with a slight more mesic shift in the south. Cool temperate rain forest remains dominant in western South America. In northwestern South America a number of sites record transitions from tropical seasonal forest to tropical dry forest and tropical rain forest to tropical seasonal forest. Sites in Central America also show a change in biome assignment to more mesic vegetation, indicative of greater plant available moisture, e.g. on the Yucat??n peninsula sites record warm evergreen forest, replacing tropical dry forest and warm mixed forest presently recorded. At 18 000±1000 14C yr BP 61 samples from 34 sites record vegetation that reflects a generally cool and dry environment. Cool grass/shrubland prevalent in southeast Brazil, Amazonian sites record tropical dry forest, warm temperate rain forest and tropical seasonal forest. Southernmost South America is dominated by cool grass/shrubland, a single site retains cool temperate rain forest indicating that forest was present at some locations at the LGM. Some sites in Central M??xico and lowland Colombia remain unchanged in their biome assignments, although the affinities that these sites have to different biomes do change between 18 000±1000 14C yr BP and present. The " unresponsive" nature of these sites results from their location and the impact of local edaphic influence.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26247467','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26247467"><span>Environmental Costs of Government-Sponsored Agrarian Settlements in Brazilian Amazonia.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Schneider, Maurício; Peres, Carlos A</p> <p>2015-01-01</p> <p>Brazil has presided over the most comprehensive agrarian reform frontier colonization program on Earth, in which ~1.2 million settlers have been translocated by successive governments since the 1970's, mostly into forested hinterlands of Brazilian Amazonia. These settlements encompass 5.3% of this ~5 million km2 region, but have contributed with 13.5% of all land conversion into agropastoral land uses. The Brazilian Federal Agrarian Agency (INCRA) has repeatedly claimed that deforestation in these areas largely predates the sanctioned arrival of new settlers. Here, we quantify rates of natural vegetation conversion across 1911 agrarian settlements allocated to 568 Amazonian counties and compare fire incidence and deforestation rates before and after the official occupation of settlements by migrant farmers. The timing and spatial distribution of deforestation and fires in our analysis provides irrefutable chronological and spatially explicit evidence of agropastoral conversion both inside and immediately outside agrarian settlements over the last decade. Deforestation rates are strongly related to local human population density and road access to regional markets. Agrarian settlements consistently accelerated rates of deforestation and fires, compared to neighboring areas outside settlements, but within the same counties. Relocated smallholders allocated to forest areas undoubtedly operate as pivotal agents of deforestation, and most of the forest clearance occurs in the aftermath of government-induced migration.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27988555','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27988555"><span>Catalogue of distribution of lizards (Reptilia: Squamata) from the Brazilian Amazonia. III. Anguidae, Scincidae, Teiidae.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ribeiro-Júnior, Marco A; Amaral, Silvana</p> <p>2016-12-09</p> <p>We present distribution data of all Anguidae, Scincidae, and Teiidae lizards known from the Brazilian Amazonia, totaling 29 species-level taxa, belonging to 14 genera. This represents 11 more species-level taxa than previously reported for these families in this area. Data were based on literature and 46,806 specimens deposited in three North American and eight Brazilian museums, including the main collections harboring Amazonian material. Most species (~55%) are endemic to Amazonia. Except for Ameiva ameiva, that is present in several environments and domains, non-endemic species are either associated with open dry (semideciduous) forest or open vegetation (savanna) enclaves in Amazonia, occupying similar environments outside Amazonia, gallery forests within the Cerrado, or present disjunct populations in the Atlantic Forest. As a whole, six taxa are widespread in Amazonia, four are restricted to eastern Amazonia, four to western Amazonia, three to southwestern Amazonia, one to northern Amazonia, and seven to the southern peripheral portion of Amazonia. Besides, two species present apparently more restricted, unique distributions. Only three species have a distribution that is congruent with one of the areas of endemism (AE) recognized for other organisms (birds and primates), of which two occur in AE Guiana and one in AE Inambari.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70043907','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70043907"><span>Stoichiometric patterns in foliar nutrient resorption across multiple scales</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Reed, Sasha C.; Townsend, Alan R.; Davidson, Eric A.; Cleveland, Cory C.</p> <p>2012-01-01</p> <p>*Nutrient resorption is a fundamental process through which plants withdraw nutrients from leaves before abscission. Nutrient resorption patterns have the potential to reflect gradients in plant nutrient limitation and to affect a suite of terrestrial ecosystem functions. *Here, we used a stoichiometric approach to assess patterns in foliar resorption at a variety of scales, specifically exploring how N : P resorption ratios relate to presumed variation in N and/or P limitation and possible relationships between N : P resorption ratios and soil nutrient availability. *N : P resorption ratios varied significantly at the global scale, increasing with latitude and decreasing with mean annual temperature and precipitation. In general, tropical sites (absolute latitudes < 23°26′) had N : P resorption ratios of < 1, and plants growing on highly weathered tropical soils maintained the lowest N : P resorption ratios. Resorption ratios also varied with forest age along an Amazonian forest regeneration chronosequence and among species in a diverse Costa Rican rain forest. *These results suggest that variations in N : P resorption stoichiometry offer insight into nutrient cycling and limitation at a variety of spatial scales, complementing other metrics of plant nutrient biogeochemistry. The extent to which the stoichiometric flexibility of resorption will help regulate terrestrial responses to global change merits further investigation.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27645139','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27645139"><span>Diversity and Structure of Fungal Communities in Neotropical Rainforest Soils: The Effect of Host Recurrence.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Schimann, Heidy; Bach, Cyrille; Lengelle, Juliette; Louisanna, Eliane; Barantal, Sandra; Murat, Claude; Buée, Marc</p> <p>2017-02-01</p> <p>The patterns of the distribution of fungal species and their potential interactions with trees remain understudied in Neotropical rainforests, which harbor more than 16,000 tree species, mostly dominated by endomycorrhizal trees. Our hypothesis was that tree species shape the non-mycorrhizal fungal assemblages in soil and litter and that the diversity of fungal communities in these two compartments is partly dependent on the coverage of trees in the Neotropical rainforest. In French Guiana, a long-term plantation and a natural forest were selected to test this hypothesis. Fungal ITS1 regions were sequenced from soil and litter samples from within the vicinity of tree species. A broad range of fungal taxa was found, with 42 orders and 14 classes. Significant spatial heterogeneity in the fungal communities was found without strong variation in the species richness and evenness among the tree plots. However, tree species shaped the fungal assemblages in the soil and litter, explaining up to 18 % of the variation among the communities in the natural forest. These results demonstrate that vegetation cover has an important effect on the structure of fungal assemblages inhabiting the soil and litter in Amazonian forests, illustrating the relative impact of deterministic processes on fungal community structures in these highly diverse ecosystems.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4527589','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4527589"><span>Environmental Costs of Government-Sponsored Agrarian Settlements in Brazilian Amazonia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2015-01-01</p> <p>Brazil has presided over the most comprehensive agrarian reform frontier colonization program on Earth, in which ~1.2 million settlers have been translocated by successive governments since the 1970’s, mostly into forested hinterlands of Brazilian Amazonia. These settlements encompass 5.3% of this ~5 million km2 region, but have contributed with 13.5% of all land conversion into agropastoral land uses. The Brazilian Federal Agrarian Agency (INCRA) has repeatedly claimed that deforestation in these areas largely predates the sanctioned arrival of new settlers. Here, we quantify rates of natural vegetation conversion across 1911 agrarian settlements allocated to 568 Amazonian counties and compare fire incidence and deforestation rates before and after the official occupation of settlements by migrant farmers. The timing and spatial distribution of deforestation and fires in our analysis provides irrefutable chronological and spatially explicit evidence of agropastoral conversion both inside and immediately outside agrarian settlements over the last decade. Deforestation rates are strongly related to local human population density and road access to regional markets. Agrarian settlements consistently accelerated rates of deforestation and fires, compared to neighboring areas outside settlements, but within the same counties. Relocated smallholders allocated to forest areas undoubtedly operate as pivotal agents of deforestation, and most of the forest clearance occurs in the aftermath of government-induced migration. PMID:26247467</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3896013','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3896013"><span>Predicting pre-Columbian anthropogenic soils in Amazonia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>McMichael, C. H.; Palace, M. W.; Bush, M. B.; Braswell, B.; Hagen, S.; Neves, E. G.; Silman, M. R.; Tamanaha, E. K.; Czarnecki, C.</p> <p>2014-01-01</p> <p>The extent and intensity of pre-Columbian impacts on lowland Amazonia have remained uncertain and controversial. Various indicators can be used to gauge the impact of pre-Columbian societies, but the formation of nutrient-enriched terra preta soils has been widely accepted as an indication of long-term settlement and site fidelity. Using known and newly discovered terra preta sites and maximum entropy algorithms (Maxent), we determined the influence of regional environmental conditions on the likelihood that terra pretas would have been formed at any given location in lowland Amazonia. Terra pretas were most frequently found in central and eastern Amazonia along the lower courses of the major Amazonian rivers. Terrain, hydrologic and soil characteristics were more important predictors of terra preta distributions than climatic conditions. Our modelling efforts indicated that terra pretas are likely to be found throughout ca 154 063 km2 or 3.2% of the forest. We also predict that terra preta formation was limited in most of western Amazonia. Model results suggested that the distribution of terra preta was highly predictable based on environmental parameters. We provided targets for future archaeological surveys under the vast forest canopy and also highlighted how few of the long-term forest inventory sites in Amazonia are able to capture the effects of historical disturbance. PMID:24403329</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2784433','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2784433"><span>Hunting and use of terrestrial fauna used by Caiçaras from the Atlantic Forest coast (Brazil)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2009-01-01</p> <p>Background The Brazilian Atlantic Forest is considered one of the hotspots for conservation, comprising remnants of rain forest along the eastern Brazilian coast. Its native inhabitants in the Southeastern coast include the Caiçaras (descendants from Amerindians and European colonizers), with a deep knowledge on the natural resources used for their livelihood. Methods We studied the use of the terrestrial fauna in three Caiçara communities, through open-ended interviews with 116 native residents. Data were checked through systematic observations and collection of zoological material. Results The dependence on the terrestrial fauna by Caiçaras is especially for food and medicine. The main species used are Didelphis spp., Dasyprocta azarae, Dasypus novemcinctus, and small birds (several species of Turdidae). Contrasting with a high dependency on terrestrial fauna resources by native Amazonians, the Caiçaras do not show a constant dependency on these resources. Nevertheless, the occasional hunting of native animals represents a complimentary source of animal protein. Conclusion Indigenous or local knowledge on native resources is important in order to promote local development in a sustainable way, and can help to conserve biodiversity, particularly if the resource is sporadically used and not commercially exploited. PMID:19930595</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24403329','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24403329"><span>Predicting pre-Columbian anthropogenic soils in Amazonia.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>McMichael, C H; Palace, M W; Bush, M B; Braswell, B; Hagen, S; Neves, E G; Silman, M R; Tamanaha, E K; Czarnecki, C</p> <p>2014-02-22</p> <p>The extent and intensity of pre-Columbian impacts on lowland Amazonia have remained uncertain and controversial. Various indicators can be used to gauge the impact of pre-Columbian societies, but the formation of nutrient-enriched terra preta soils has been widely accepted as an indication of long-term settlement and site fidelity. Using known and newly discovered terra preta sites and maximum entropy algorithms (Maxent), we determined the influence of regional environmental conditions on the likelihood that terra pretas would have been formed at any given location in lowland Amazonia. Terra pretas were most frequently found in central and eastern Amazonia along the lower courses of the major Amazonian rivers. Terrain, hydrologic and soil characteristics were more important predictors of terra preta distributions than climatic conditions. Our modelling efforts indicated that terra pretas are likely to be found throughout ca 154 063 km(2) or 3.2% of the forest. We also predict that terra preta formation was limited in most of western Amazonia. Model results suggested that the distribution of terra preta was highly predictable based on environmental parameters. We provided targets for future archaeological surveys under the vast forest canopy and also highlighted how few of the long-term forest inventory sites in Amazonia are able to capture the effects of historical disturbance.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1389499','SCIGOV-DOEDE'); return false;" href="https://www.osti.gov/servlets/purl/1389499"><span>Worldwide Organic Soil Carbon and Nitrogen Data (1986) (NDP-018)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/dataexplorer">DOE Data Explorer</a></p> <p>Zinke, P. J. [Univ. of California, Berkeley, CA (United States); Stangenberger, A. G. [Univ. of California, Berkeley, CA (United States); Post, W. M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Emanuel, W. R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Olson, J. S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Millemann, R. E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Boden, T. A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)</p> <p>1986-01-01</p> <p>This data base was begun with the collection and analysis of soil samples from California. Additional data came from soil surveys of Italy, Greece, Iran, Thailand, Vietnam, various tropical Amazonian areas, and U.S. forests and from the soil-survey literature. The analyzed samples were collected at uniform soil-depth increments and included bulk-density determinations. The data on each sample are soil profile number; soil profile carbon content; soil profile nitrogen content; sampling site latitude and longitude; site elevation; profile literature reference source; and soil profile codes for Holdridge life zone, Olson ecosystem type, and parent material. These data may be used to estimate the size of the soil organic carbon and nitrogen pools at equilibrium with natural soil-forming factors.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/56204','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/56204"><span>Implications of land-use change on forest carbon stocks in the eastern United States</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Joshua Puhlick; Christopher Woodall; Aaron Weiskittel</p> <p>2017-01-01</p> <p>Given the substantial role that forests play in removing CO2 from the atmosphere, there has been a growing need to evaluate the carbon (C) implications of various forest management and land-use decisions. Although assessment of land-use change is central to national-level greenhouse gas monitoring guidelines, it is rarely incorporated into forest...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017BGeo...14.2429D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017BGeo...14.2429D"><span>Modelling the genesis of equatorial podzols: age and implications for carbon fluxes</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Doupoux, Cédric; Merdy, Patricia; Régina Montes, Célia; Nunan, Naoise; José Melfi, Adolpho; José Ribeiro Pereira, Osvaldo; Lucas, Yves</p> <p>2017-05-01</p> <p>Amazonian podzols store huge amounts of carbon and play a key role in transferring organic matter to the Amazon River. In order to better understand their C dynamics, we modelled the formation of representative Amazonian podzol profiles by constraining both total carbon and radiocarbon. We determined the relationships between total carbon and radiocarbon in organic C pools numerically by setting constant C and 14C inputs over time. The model was an effective tool for determining the order of magnitude of the carbon fluxes and the time of genesis of the main carbon-containing horizons, i.e. the topsoil and deep Bh. We performed retrocalculations to take into account the bomb carbon in the young topsoil horizons (calculated apparent 14C age from 62 to 109 years). We modelled four profiles representative of Amazonian podzols, two profiles with an old Bh (calculated apparent 14C age 6.8 × 103 and 8.4 × 103 years) and two profiles with a very old Bh (calculated apparent 14C age 23.2 × 103 and 25.1 × 103 years). The calculated fluxes from the topsoil to the perched water table indicate that the most waterlogged zones of the podzolized areas are the main source of dissolved organic matter found in the river network. It was necessary to consider two Bh carbon pools to accurately represent the carbon fluxes leaving the Bh as observed in previous studies. We found that the genesis time of the studied soils was necessarily longer than 15 × 103 and 130 × 103 years for the two younger and two older Bhs, respectively, and that the genesis time calculated considering the more likely settings runs to around 15 × 103-25 × 103 and 150 × 103-250 × 103 years, respectively.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.B51E0450D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.B51E0450D"><span>Constraining the Sensitivity of Amazonian Rainfall with Observations of Surface Temperature</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dolman, A. J.; von Randow, C.; de Oliveira, G. S.; Martins, G.; Nobre, C. A.</p> <p>2016-12-01</p> <p>Earth System models generally do a poor job in predicting Amazonian rainfall, necessitating the need to look for observational constraints on their predictability. We use observed surface temperature and precipitation of the Amazon and a set of 21 CMIP5 models to derive an observational constraint of the sensitivity of rainfall to surface temperature (dP/dT). From first principles such a relation between the surface temperature of the earth and the amount of precipitation through the surface energy balance should exist, particularly in the tropics. When de-trended anomalies in surface temperature and precipitation from a set of datasets are plotted, a clear linear relation between surface temperature and precipitation appears. CMIP5 models show a similar relation with relatively cool models having a larger sensitivity, producing more rainfall. Using the ensemble of models and the observed surface temperature we were able to derive an emerging constraint, reducing the dPdt sensitivity of the CMIP5 model from -0.75 mm day-1 0C-1 (+/- 0.54 SD) to -0.77 mm day-1 0C-1 with a reduced uncertainty of about a factor 5. dPdT from the observation is -0.89 mm day-1 0C-1 . We applied the method to wet and dry season separately noticing that in the wet season we shifted the mean and reduced uncertainty, while in the dry season we very much reduced uncertainty only. The method can be applied to other model simulations such as specific deforestation scenarios to constrain the sensitivity of rainfall to surface temperature. We discuss the implications of the constrained sensitivity for future Amazonian predictions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22842094','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22842094"><span>From Amazonia to the Atlantic forest: molecular phylogeny of Phyzelaphryninae frogs reveals unexpected diversity and a striking biogeographic pattern emphasizing conservation challenges.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fouquet, Antoine; Loebmann, Daniel; Castroviejo-Fisher, Santiago; Padial, José M; Orrico, Victor G D; Lyra, Mariana L; Roberto, Igor Joventino; Kok, Philippe J R; Haddad, Célio F B; Rodrigues, Miguel T</p> <p>2012-11-01</p> <p>Documenting the Neotropical amphibian diversity has become a major challenge facing the threat of global climate change and the pace of environmental alteration. Recent molecular phylogenetic studies have revealed that the actual number of species in South American tropical forests is largely underestimated, but also that many lineages are millions of years old. The genera Phyzelaphryne (1 sp.) and Adelophryne (6 spp.), which compose the subfamily Phyzelaphryninae, include poorly documented, secretive, and minute frogs with an unusual distribution pattern that encompasses the biotic disjunction between Amazonia and the Atlantic forest. We generated >5.8 kb sequence data from six markers for all seven nominal species of the subfamily as well as for newly discovered populations in order to (1) test the monophyly of Phyzelaphryninae, Adelophryne and Phyzelaphryne, (2) estimate species diversity within the subfamily, and (3) investigate their historical biogeography and diversification. Phylogenetic reconstruction confirmed the monophyly of each group and revealed deep subdivisions within Adelophryne and Phyzelaphryne, with three major clades in Adelophryne located in northern Amazonia, northern Atlantic forest and southern Atlantic forest. Our results suggest that the actual number of species in Phyzelaphryninae is, at least, twice the currently recognized species diversity, with almost every geographically isolated population representing an anciently divergent candidate species. Such results highlight the challenges for conservation, especially in the northern Atlantic forest where it is still degraded at a fast pace. Molecular dating revealed that Phyzelaphryninae originated in Amazonia and dispersed during early Miocene to the Atlantic forest. The two Atlantic forest clades of Adelophryne started to diversify some 7 Ma minimum, while the northern Amazonian Adelophryne diversified much earlier, some 13 Ma minimum. This striking biogeographic pattern coincides with major events that have shaped the face of the South American continent, as we know it today. Copyright © 2012 Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JGRE..118.1873A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JGRE..118.1873A"><span>3D morphometry of valley networks on Mars from HRSC/MEX DEMs: Implications for climatic evolution through time</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ansan, V.; Mangold, N.</p> <p>2013-09-01</p> <p>valley networks have been identified mainly in the Noachian heavily cratered uplands. Eight dense branching valley networks were studied in Noachian terrains of Huygens, Newcomb and Kepler craters, south Tyrrhena Terra, and Thaumasia, in Hesperian terrains of Echus Plateau and west Eberswalde craters, and in Amazonian terrains of Alba Patera, using images and digital elevation models from the Mars Express High Resolution Stereo Camera to determine 2D and 3D morphometric parameters. Extracted geomorphic parameters show similar geometry to terrestrial valleys: drainage densities, organization from bifurcation ratios and lengths ratios, Hack exponent consistent with terrestrial values of ~0.6, and progressive deepening of valleys with increasing Strahler order. In addition, statistics on valley depths indicate a deeper incision of Noachian valleys compared to younger post-Noachian valleys (<25 m for Amazonian ones compared to >100 m for Noachian ones), showing a strong difference in fluvial erosion. These characteristics show that dense Martian valley networks formed by overland flows in relation to a global atmospheric water cycle in Noachian epoch and confirm that the later stages of activity may be related to shorter duration of activity, distinct climatic conditions, and/or regional processes, or conditions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26108003','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26108003"><span>Phlebotominae sand flies (Diptera: Psychodidae): potential vectors of American cutaneous leishmaniasis agents in the area associated with the Santo Antônio Hydroelectric System in Western Amazonian Brazil.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Galardo, Allan Kardec Ribeiro; Galardo, Clícia Denis; Silveira, Guilherme Abbad; Ribeiro, Kaio Augusto Nabas; Hijjar, Andréa Valadão; Oliveira, Liliane Leite; Dos Santos, Thiago Vasconcelos</p> <p>2015-01-01</p> <p>An entomological study was conducted as part of a vector-monitoring program in the area associated with the Santo Antônio hydroelectric system in State of Rondônia, Western Amazonian Brazil. Fourteen sampling sites were surveyed to obtain data on the potential vectors of Leishmania spp. in the area. Sand flies were collected from 2011 to 2014 during the months of January/February (rainy season), May/June (dry season), and September/October (intermediary season) using light traps arranged in three vertical strata (0.5, 1, and 20m). A total of 7,575 individuals belonging to 62 species/subspecies were collected. The five most frequently collected sand flies were Psychodopygus davisi (Root) (36.67%), Trichophoromyia ubiquitalis (Mangabeira) (8.51%), Nyssomyia umbratilis (Ward & Fraiha) (6.14%), Bichromomyia flaviscutellata (Mangabeira) (5.74%), and Psychodopygus complexus (Mangabeira) (5.25%). These species have been implicated in the transmission of American cutaneous leishmaniasis agents in the Brazilian Amazon region and described as potential vectors of this disease in the study area. Additional surveillance is needed, especially in areas where these five species of sand fly are found.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24933800','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24933800"><span>Sodium fertilization increases termites and enhances decomposition in an Amazonian forest.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kaspari, Michael; Clay, Natalie A; Donoso, David A; Yanoviak, Steven P</p> <p>2014-04-01</p> <p>Added Na was used to determine whether litter decomposition and associated fungal biomass and termites are limited by Na availability in a lowland tropical rainforest at Yasuni, Ecuador. This is a partial test of the "sodium ecosystem respiration" (SER) hypothesis that posits Na is critical for consumers but not plants, that Na shortfall is more likely on highly weathered soils inland from oceanic aerosols, and that this shortfall results in decreased decomposer activity. We fertilized 4 x 4 m plots twice a month for a year with quantities of Na comparable to those falling on a coastal tropical rainforest. Decomposition rates of four substrates were consistently higher on +NaCl plots by up to 70% for cellulose, and 78%, 68%, and 29% for three woods of increasing percentage lignin. The density of termite workers averaged 17-fold higher on +NaCl plots; fungal biomass failed to differ. After controlling for temperature and precipitation, which co-limit gross primay productivity (GPP) and ecosystem respiration (ER), these results suggest that Na shortfall is an agent enhancing the storage of coarse woody debris in inland tropical forests.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1570345','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1570345"><span>Terrestrial vegetation redistribution and carbon balance under climate change</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lucht, Wolfgang; Schaphoff, Sibyll; Erbrecht, Tim; Heyder, Ursula; Cramer, Wolfgang</p> <p>2006-01-01</p> <p>Background Dynamic Global Vegetation Models (DGVMs) compute the terrestrial carbon balance as well as the transient spatial distribution of vegetation. We study two scenarios of moderate and strong climate change (2.9 K and 5.3 K temperature increase over present) to investigate the spatial redistribution of major vegetation types and their carbon balance in the year 2100. Results The world's land vegetation will be more deciduous than at present, and contain about 125 billion tons of additional carbon. While a recession of the boreal forest is simulated in some areas, along with a general expansion to the north, we do not observe a reported collapse of the central Amazonian rain forest. Rather, a decrease of biomass and a change of vegetation type occurs in its northeastern part. The ability of the terrestrial biosphere to sequester carbon from the atmosphere declines strongly in the second half of the 21st century. Conclusion Climate change will cause widespread shifts in the distribution of major vegetation functional types on all continents by the year 2100. PMID:16930462</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27478703','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27478703"><span>Human population and socioeconomic modulators of conservation performance in 788 Amazonian and Atlantic Forest reserves.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>de Marques, Ana Alice B; Schneider, Mauricio; Peres, Carlos A</p> <p>2016-01-01</p> <p>Protected areas form a quintessential component of the global strategy to perpetuate tropical biodiversity within relatively undisturbed wildlands, but they are becoming increasingly isolated by rapid agricultural encroachment. Here we consider a network of 788 forest protected areas (PAs) in the world's largest tropical country to examine the degree to which they remain intact, and their responses to multiple biophysical and socioeconomic variables potentially affecting natural habitat loss under varying contexts of rural development. PAs within the complex Brazilian National System of Conservation Units (SNUC) are broken down into two main classes-strictly protected and sustainable use. Collectively, these account for 22.6% of the forest biomes within Brazil's national territory, primarily within the Amazon and the Atlantic Forest, but are widely variable in size, ecoregional representation, management strategy, and the degree to which they are threatened by human activities both within and outside reserve boundaries. In particular, we examine the variation in habitat conversion rates in both strictly protected and sustainable use reserves as a function of the internal and external human population density, and levels of land-use revenue in adjacent human-dominated landscapes. Our results show that PAs surrounded by heavily settled agro-pastoral landscapes face much greater challenges in retaining their natural vegetation, and that strictly protected areas are considerably less degraded than sustainable use reserves, which can rival levels of habitat degradation within adjacent 10-km buffer areas outside.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4950577','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4950577"><span>Human population and socioeconomic modulators of conservation performance in 788 Amazonian and Atlantic Forest reserves</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Schneider, Mauricio; Peres, Carlos A.</p> <p>2016-01-01</p> <p>Protected areas form a quintessential component of the global strategy to perpetuate tropical biodiversity within relatively undisturbed wildlands, but they are becoming increasingly isolated by rapid agricultural encroachment. Here we consider a network of 788 forest protected areas (PAs) in the world’s largest tropical country to examine the degree to which they remain intact, and their responses to multiple biophysical and socioeconomic variables potentially affecting natural habitat loss under varying contexts of rural development. PAs within the complex Brazilian National System of Conservation Units (SNUC) are broken down into two main classes—strictly protected and sustainable use. Collectively, these account for 22.6% of the forest biomes within Brazil’s national territory, primarily within the Amazon and the Atlantic Forest, but are widely variable in size, ecoregional representation, management strategy, and the degree to which they are threatened by human activities both within and outside reserve boundaries. In particular, we examine the variation in habitat conversion rates in both strictly protected and sustainable use reserves as a function of the internal and external human population density, and levels of land-use revenue in adjacent human-dominated landscapes. Our results show that PAs surrounded by heavily settled agro-pastoral landscapes face much greater challenges in retaining their natural vegetation, and that strictly protected areas are considerably less degraded than sustainable use reserves, which can rival levels of habitat degradation within adjacent 10-km buffer areas outside. PMID:27478703</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009BGD.....6.3133V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009BGD.....6.3133V"><span>Liana infestation impacts tree growth in a lowland tropical moist forest</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>van der Heijden, G. M. F.; Phillips, O. L.</p> <p>2009-03-01</p> <p>Stand-level estimates of the effect of lianas on tree growth in mature tropical forests are needed to evaluate the functional impact of lianas and their potential to affect the ability of tropical forests to sequester carbon, but these are currently lacking. Using data collected on tree growth rates, local growing conditions and liana competition in five permanent sampling plots in Amazonian Peru, we present the first such estimates of the effect of lianas on above-ground productivity of trees. By constructing a multi-level linear mixed effect model to predict individual tree diameter growth model using individual tree growth conditions, we were able to estimate stand-level above-ground biomass (AGB) increment in the absence of lianas. We show that lianas, mainly by competing above-ground with trees, reduce tree annual above-ground stand-level biomass by ~10%, equivalent to 0.51 Mg dry weight ha-1 yr-1 or 0.25 Mg C ha-1 yr-1. AGB increment of lianas themselves was estimated to be 0.15 Mg dry weight ha-1 yr-1 or 0.07 Mg C ha-1 yr-1, thus only compensating ~29% of the liana-induced reduction in stand-level AGB increment. Increasing liana pressure on tropical forests may therefore not only reduce their carbon storage capacity, by indirectly promoting tree species with low-density wood, but also their rate of carbon uptake, with potential consequences for the rate of increase in atmospheric carbon dioxide.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009BGeo....6.2217V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009BGeo....6.2217V"><span>Liana infestation impacts tree growth in a lowland tropical moist forest</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>van der Heijden, G. M. F.; Phillips, O. L.</p> <p>2009-10-01</p> <p>Ecosystem-level estimates of the effect of lianas on tree growth in mature tropical forests are needed to evaluate the functional impact of lianas and their potential to affect the ability of tropical forests to sequester carbon, but these are currently lacking. Using data collected on tree growth rates, local growing conditions and liana competition in five permanent sampling plots in Amazonian Peru, we present the first ecosystem-level estimates of the effect of lianas on above-ground productivity of trees. By first constructing a multi-level linear mixed effect model to predict individual-tree diameter growth model using individual-tree growth conditions, we were able to then estimate stand-level above-ground biomass (AGB) increment in the absence of lianas. We show that lianas, mainly by competing above-ground with trees, reduce tree annual above-ground stand-level biomass increment by ~10%, equivalent to 0.51 Mg dry weight ha-1 yr-1 or 0.25 Mg C ha-1 yr-1. AGB increment of lianas themselves was estimated to be 0.15 Mg dry weight ha-1 yr-1 or 0.07 Mg C ha-1 yr-1, thus only compensating ~29% of the liana-induced reduction in ecosystem AGB increment. Increasing liana pressure on tropical forests will therefore not only tend to reduce their carbon storage capacity, by indirectly promoting tree species with low-density wood, but also their rate of carbon uptake, with potential consequences for the rate of increase in atmospheric carbon dioxide.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/14957','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/14957"><span>Understanding predation: implications toward forest management</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Harvey R. Smith</p> <p>1991-01-01</p> <p>It is generally accepted that when gypsy moths rest in the litter survival is low due to predation by ground-foraging generalist predators and that predation can maintain these populations indefinitely. Forest Service research on predators of gypsy moth continues to focus on population dynamics, the mechanisms of predation and forest management implications.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70025743','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70025743"><span>Resurfacing history of the northern plains of Mars based on geologic mapping of Mars Global Surveyor data</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Tanaka, K.L.; Skinner, J.A.; Hare, T.M.; Joyal, T.; Wenker, A.</p> <p>2003-01-01</p> <p>Geologic mapping of the northern plains of Mars, based on Mars Orbiter Laser Altimeter topography and Viking and Mars Orbiter Camera images, reveals new insights into geologic processes and events in this region during the Hesperian and Amazonian Periods. We propose four successive stages of lowland resurfacing likely related to the activity of near-surface volatiles commencing at the highland-lowland boundary (HLB) and progressing to lower topographic levels as follows (highest elevations indicated): Stage 1, upper boundary plains, Early Hesperian, <-2.0 to -2.9 km; Stage 2, lower boundary plains and outflow channel dissection, Late Hesperian, <-2.7 to -4.0 km; Stage 3, Vastitas Borealis Formation (VBF) surface, Late Hesperian to Early Amazonian, <-3.1 to -4.1 km; and Stage 4, local chaos zones, Early Amazonian, <-3.8 to -5.0 km. At Acidalia Mensa, Stage 2 and 3 levels may be lower (<-4.4 and -4.8 km, respectively). Contractional ridges form the dominant structure in the plains and developed from near the end of the Early Hesperian to the Early Amazonian. Geomorphic evidence for a northern-plains-filling ocean during Stage 2 is absent because one did not form or its evidence was destroyed by Stage 3 resurfacing. Remnants of possible Amazonian dust mantles occur on top of the VBF. The north polar layered deposits appear to be made up of an up to kilometer-thick lower sequence of sandy layers Early to Middle Amazonian in age overlain by Late Amazonian ice-rich dust layers; both units appear to have outliers, suggesting that they once were more extensive.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25716785','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25716785"><span>A Miocene hyperdiverse crocodylian community reveals peculiar trophic dynamics in proto-Amazonian mega-wetlands.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Salas-Gismondi, Rodolfo; Flynn, John J; Baby, Patrice; Tejada-Lara, Julia V; Wesselingh, Frank P; Antoine, Pierre-Olivier</p> <p>2015-04-07</p> <p>Amazonia contains one of the world's richest biotas, but origins of this diversity remain obscure. Onset of the Amazon River drainage at approximately 10.5 Ma represented a major shift in Neotropical ecosystems, and proto-Amazonian biotas just prior to this pivotal episode are integral to understanding origins of Amazonian biodiversity, yet vertebrate fossil evidence is extraordinarily rare. Two new species-rich bonebeds from late Middle Miocene proto-Amazonian deposits of northeastern Peru document the same hyperdiverse assemblage of seven co-occurring crocodylian species. Besides the large-bodied Purussaurus and Mourasuchus, all other crocodylians are new taxa, including a stem caiman-Gnatusuchus pebasensis-bearing a massive shovel-shaped mandible, procumbent anterior and globular posterior teeth, and a mammal-like diastema. This unusual species is an extreme exemplar of a radiation of small caimans with crushing dentitions recording peculiar feeding strategies correlated with a peak in proto-Amazonian molluscan diversity and abundance. These faunas evolved within dysoxic marshes and swamps of the long-lived Pebas Mega-Wetland System and declined with inception of the transcontinental Amazon drainage, favouring diversification of longirostrine crocodylians and more modern generalist-feeding caimans. The rise and demise of distinctive, highly productive aquatic ecosystems substantially influenced evolution of Amazonian biodiversity hotspots of crocodylians and other organisms throughout the Neogene. © 2015 The Author(s) Published by the Royal Society. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5644977','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5644977"><span>Woody lianas increase in dominance and maintain compositional integrity across an Amazonian dam-induced fragmented landscape</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Peres, Carlos A.; Benchimol, Maíra; Bunnefeld, Lynsey; Dent, Daisy H.</p> <p>2017-01-01</p> <p>Tropical forest fragmentation creates insular biological communities that undergo species loss and changes in community composition over time, due to area- and edge-effects. Woody lianas thrive in degraded and secondary forests, due to their competitive advantage over trees in these habitats. Lianas compete both directly and indirectly with trees, increasing tree mortality and turnover. Despite our growing understanding of liana-tree dynamics, we lack detailed knowledge of the assemblage-level responses of lianas themselves to fragmentation, particularly in evergreen tropical forests. We examine the responses of both sapling and mature liana communities to landscape-scale forest insularization induced by a mega hydroelectric dam in the Brazilian Amazon. Detailed field inventories were conducted on islands created during reservoir filling, and in nearby mainland continuous forest. We assess the relative importance of variables associated with habitat fragmentation such as area, isolation, surrounding forest cover, fire and wind disturbance, on liana community attributes including abundance, basal area, diversity, and composition. We also explore patterns of liana dominance relative to tree saplings and adults ≥10 cm diameter at breast height. We find that 1) liana community composition remains remarkably similar across mainland continuous forest and islands, regardless of extreme area- and edge- effects and the loss of vertebrate dispersers in the latter; and 2) lianas are increasing in dominance relative to trees in the sapling layer in the most degraded islands, with both the amount of forest cover surrounding islands and fire disturbance history predicting liana dominance. Our data suggest that liana communities persist intact in isolated forests, regardless of extreme area- and edge-effects; while in contrast, tree communities simultaneously show evidence of increased turnover and supressed recruitment. These processes may lead to lianas becoming a dominant component of this dam-induced fragmented landscape in the future, due to their competitive advantage over trees in degraded forest habitats. Additional loss of tree biomass and diversity brought about through competition with lianas, and the concurrent loss of carbon storage, should be accounted for in impact assessments of future dam development. PMID:29040272</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29040272','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29040272"><span>Woody lianas increase in dominance and maintain compositional integrity across an Amazonian dam-induced fragmented landscape.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jones, Isabel L; Peres, Carlos A; Benchimol, Maíra; Bunnefeld, Lynsey; Dent, Daisy H</p> <p>2017-01-01</p> <p>Tropical forest fragmentation creates insular biological communities that undergo species loss and changes in community composition over time, due to area- and edge-effects. Woody lianas thrive in degraded and secondary forests, due to their competitive advantage over trees in these habitats. Lianas compete both directly and indirectly with trees, increasing tree mortality and turnover. Despite our growing understanding of liana-tree dynamics, we lack detailed knowledge of the assemblage-level responses of lianas themselves to fragmentation, particularly in evergreen tropical forests. We examine the responses of both sapling and mature liana communities to landscape-scale forest insularization induced by a mega hydroelectric dam in the Brazilian Amazon. Detailed field inventories were conducted on islands created during reservoir filling, and in nearby mainland continuous forest. We assess the relative importance of variables associated with habitat fragmentation such as area, isolation, surrounding forest cover, fire and wind disturbance, on liana community attributes including abundance, basal area, diversity, and composition. We also explore patterns of liana dominance relative to tree saplings and adults ≥10 cm diameter at breast height. We find that 1) liana community composition remains remarkably similar across mainland continuous forest and islands, regardless of extreme area- and edge- effects and the loss of vertebrate dispersers in the latter; and 2) lianas are increasing in dominance relative to trees in the sapling layer in the most degraded islands, with both the amount of forest cover surrounding islands and fire disturbance history predicting liana dominance. Our data suggest that liana communities persist intact in isolated forests, regardless of extreme area- and edge-effects; while in contrast, tree communities simultaneously show evidence of increased turnover and supressed recruitment. These processes may lead to lianas becoming a dominant component of this dam-induced fragmented landscape in the future, due to their competitive advantage over trees in degraded forest habitats. Additional loss of tree biomass and diversity brought about through competition with lianas, and the concurrent loss of carbon storage, should be accounted for in impact assessments of future dam development.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26153984','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26153984"><span>Diverse Early Life-History Strategies in Migratory Amazonian Catfish: Implications for Conservation and Management.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hegg, Jens C; Giarrizzo, Tommaso; Kennedy, Brian P</p> <p>2015-01-01</p> <p>Animal migrations provide important ecological functions and can allow for increased biodiversity through habitat and niche diversification. However, aquatic migrations in general, and those of the world's largest fish in particular, are imperiled worldwide and are often poorly understood. Several species of large Amazonian catfish carry out some of the longest freshwater fish migrations in the world, travelling from the Amazon River estuary to the Andes foothills. These species are important apex predators in the main stem rivers of the Amazon Basin and make up the region's largest fishery. They are also the only species to utilize the entire Amazon Basin to complete their life cycle. Studies indicate both that the fisheries may be declining due to overfishing, and that the proposed and completed dams in their upstream range threaten spawning migrations. Despite this, surprisingly little is known about the details of these species' migrations, or their life history. Otolith microchemistry has been an effective method for quantifying and reconstructing fish migrations worldwide across multiple spatial scales and may provide a powerful tool to understand the movements of Amazonian migratory catfish. Our objective was to describe the migratory behaviors of the three most populous and commercially important migratory catfish species, Dourada (Brachyplatystoma rousseauxii), Piramutaba (Brachyplatystoma vaillantii), and Piraíba (Brachyplatystoma filamentosum). We collected fish from the mouth of the Amazon River and the Central Amazon and used strontium isotope signatures ((87)Sr/(86)Sr) recorded in their otoliths to determine the location of early rearing and subsequent. Fish location was determined through discriminant function classification, using water chemistry data from the literature as a training set. Where water chemistry data was unavailable, we successfully in predicted (87)Sr/(86)Sr isotope values using a regression-based approach that related the geology of the upstream watershed to the Sr isotope ratio. Our results provide the first reported otolith microchemical reconstruction of Brachyplatystoma migratory movements in the Amazon Basin. Our results indicate that juveniles exhibit diverse rearing strategies, rearing in both upstream and estuary environments. This contrasts with the prevailing understanding that juveniles rear in the estuary before migrating upstream; however, it is supported by some fisheries data that has indicated the presence of alternate spawning and rearing life-histories. The presence of alternate juvenile rearing strategies may have important implications for conservation and management of the fisheries in the region.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005GPC....47...99B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005GPC....47...99B"><span>Gender-specific out-migration, deforestation and urbanization in the Ecuadorian Amazon</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barbieri, Alisson F.; Carr, David L.</p> <p>2005-07-01</p> <p>The Ecuadorian Amazon, one of the richest reserves of biodiversity in the world, has faced one of the highest rates of deforestation of any Amazonian nation. Most of this forest elimination has been caused by agricultural colonization that followed the discovery of oil fields in 1967. Since the 1990s, an increasing process of urbanization has also engendered new patterns of population mobility within the Amazon, along with traditional ways by which rural settlers make their living. However, while very significant in its effects on deforestation, urbanization and regional development, population mobility within the Amazon has hardly been studied at all, as well as the distinct migration patterns between men and women. This paper uses a longitudinal dataset of 250 farm households in the Northern Ecuadorian Amazon to understand differentials between men and women migrants to urban and rural destinations and between men and women non-migrants. First, we use hazard analysis based on the Kaplan-Meier (KM) estimator to obtain the cumulative probability that an individual living in the study area in 1990 or at time t, will out-migrated at some time, t+ n, before 1999. Results indicate that out-migration to other rural areas in the Amazon, especially pristine areas is considerably greater than out-migration to the growing, but still incipient, Amazonian urban areas. Furthermore, men are more likely to out-migrate to rural areas than women, while the reverse occurs for urban areas. Difference-of-means tests were employed to examine potential factors accounting for differentials between male and female out-migration to urban and rural areas. Among the key results, relative to men younger women are more likely to out-migrate to urban areas; more difficult access from farms to towns and roads constrains women's migration; and access to new lands in the Amazon-an important cause of further deforestation-is more associated with male out-migration. Economic factors such as engagement in on-farm work, increasing resource scarcity-measured by higher population density at the farm and reduction in farm land on forest and crops-and increase in pasture land are more associated with male out-migration to rural areas. On the other hand, increasing resource scarcity, higher population density and weaker migration networks are more associated with female out-migration to urban areas. Thus, a "vicious cycle" is created: Pressure over land leads to deforestation in most or all farm forest areas and reduces the possibilities for further agricultural extensification (deforestation); out-migration, especially male out-migration, occurs to other rural or forest areas in the Amazon (with women being more likely to choose urban destinations); and, giving continuing population growth and pressures in the new settled areas, new pressures promote further out-migration to rural destinations and unabated deforestation.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70035512','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70035512"><span>Pollen-based biome reconstructions for Latin America at 0, 6000 and 18 000 radiocarbon years ago</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Marchant, R.; Cleef, A.; Harrison, S.P.; Hooghiemstra, H.; Markgraf, Vera; Van Boxel, J.; Ager, T.; Almeida, L.; Anderson, R.; Baied, C.; Behling, H.; Berrio, J.C.; Burbridge, R.; Bjorck, S.; Byrne, R.; Bush, M.; Duivenvoorden, J.; Flenley, J.; De Oliveira, P.; Van Gee, B.; Graf, K.; Gosling, W.D.; Harbele, S.; Van Der Hammen, T.; Hansen, B.; Horn, S.; Kuhry, P.; Ledru, M.-P.; Mayle, F.; Leyden, B.; Lozano-Garcia, S.; Melief, A.M.; Moreno, P.; Moar, N.T.; Prieto, A.; Van Reenen, G.; Salgado-Labouriau, M.; Schabitz, F.; Schreve-Brinkman, E. J.; Wille, M.</p> <p>2009-01-01</p> <p>The biomisation method is used to reconstruct Latin American vegetation at 6000??500 and 18 000??1000 radiocarbon years before present ( 14C yr BP) from pollen data. Tests using modern pollen data from 381 samples derived from 287 locations broadly reproduce potential natural vegetation. The strong temperature gradient associated with the Andes is recorded by a transition from high altitude cool grass/shrubland and cool mixed forest to mid-altitude cool temperate rain forest, to tropical dry, seasonal and rain forest at low altitudes. Reconstructed biomes from a number of sites do not match the potential vegetation due to local factors such as human impact, methodological artefacts and mechanisms of pollen representivity of the parent vegetation. At 6000??500 14C yr BP 255 samples are analysed from 127 sites. Differences between the modern and the 6000??500 14C yr BP reconstruction are comparatively small; change relative to the modern reconstruction are mainly to biomes characteristic of drier climate in the north of the region with a slight more mesic shift in the south. Cool temperate rain forest remains dominant in western South America. In northwestern South America a number of sites record transitions from tropical seasonal forest to tropical dry forest and tropical rain forest to tropical seasonal forest. Sites in Central America show a change in biome assignment, but to more mesic vegetation, indicative of greater plant available moisture, e.g. on the Yucat??n peninsula sites record warm evergreen forest, replacing tropical dry forest and warm mixed forest presently recorded. At 18 000??1000 14C yr BP 61 samples from 34 sites record vegetation reflecting a generally cool and dry environment. Cool grass/shrubland is prevalent in southeast Brazil whereas Amazonian sites record tropical dry forest, warm temperate rain forest and tropical seasonal forest. Southernmost South America is dominated by cool grass/shrubland, a single site retains cool temperate rain forest indicating that forest was present at some locations at the LGM. Some sites in Central Mexico and lowland Colombia remain unchanged in the biome assignments of warm mixed forest and tropical dry forest respectively, although the affinities that these sites have to different biomes do change between 18000??1000 14C yr BP and present. The "unresponsive" nature of these sites results from their location and the impact of local edaphic influence. ?? Author(s) 2009.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22912787','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22912787"><span>The effects of processing non-timber forest products and trade partnerships on people's well-being and forest conservation in Amazonian societies.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Morsello, Carla; Ruiz-Mallén, Isabel; Diaz, Maria Dolores Montoya; Reyes-García, Victoria</p> <p>2012-01-01</p> <p>This study evaluated whether processing non-timber forest products (NTFPs) and establishing trade partnerships between forest communities and companies enhance the outcomes of NTFP commercialization. In particular, we evaluated whether product processing, partnerships, or their combination was associated with a number of outcomes related to the well-being of forest inhabitants and forest conservation. We based our analyses on ethnographic and quantitative data (i.e., survey and systematic observations) gathered at seven communities from five societies of the Brazilian and Bolivian Amazon. Our results indicated that product processing and partnerships do not represent a silver bullet able to improve the results of NTFP commercialization in terms of well-being and conservation indicators. Compared with cases without interventions, households adopting partnerships but not product processing were most often associated with improved economic proxies of well-being (total income, NTFP income, food consumption and gender equality in income). In comparison, the combination of product processing and partnerships was associated with similar outcomes. Unexpectedly, product processing alone was associated with negative outcomes in the economic indicators of well-being. All of the investigated strategies were associated with less time spent in social and cultural activities. With respect to forest conservation, the strategies that included a partnership with or without processing produced similar results: while household deforestation tended to decrease, the hunting impact increased. Processing alone was also associated with higher levels of hunting, though it did not reduce deforestation. Our results indicate that establishing partnerships may enhance the outcomes of NTFP trade in terms of the financial outcomes of local communities, but practitioners need to use caution when adopting the processing strategy and they need to evaluate potential negative results for indicators of social and cultural activities. With respect to conservation, the three strategies are promising for reducing deforestation, but more pervasive impacts, such as hunting, might increase.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3422238','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3422238"><span>The Effects of Processing Non-Timber Forest Products and Trade Partnerships on People's Well-Being and Forest Conservation in Amazonian Societies</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Morsello, Carla; Ruiz-Mallén, Isabel; Diaz, Maria Dolores Montoya; Reyes-García, Victoria</p> <p>2012-01-01</p> <p>This study evaluated whether processing non-timber forest products (NTFPs) and establishing trade partnerships between forest communities and companies enhance the outcomes of NTFP commercialization. In particular, we evaluated whether product processing, partnerships, or their combination was associated with a number of outcomes related to the well-being of forest inhabitants and forest conservation. We based our analyses on ethnographic and quantitative data (i.e., survey and systematic observations) gathered at seven communities from five societies of the Brazilian and Bolivian Amazon. Our results indicated that product processing and partnerships do not represent a silver bullet able to improve the results of NTFP commercialization in terms of well-being and conservation indicators. Compared with cases without interventions, households adopting partnerships but not product processing were most often associated with improved economic proxies of well-being (total income, NTFP income, food consumption and gender equality in income). In comparison, the combination of product processing and partnerships was associated with similar outcomes. Unexpectedly, product processing alone was associated with negative outcomes in the economic indicators of well-being. All of the investigated strategies were associated with less time spent in social and cultural activities. With respect to forest conservation, the strategies that included a partnership with or without processing produced similar results: while household deforestation tended to decrease, the hunting impact increased. Processing alone was also associated with higher levels of hunting, though it did not reduce deforestation. Our results indicate that establishing partnerships may enhance the outcomes of NTFP trade in terms of the financial outcomes of local communities, but practitioners need to use caution when adopting the processing strategy and they need to evaluate potential negative results for indicators of social and cultural activities. With respect to conservation, the three strategies are promising for reducing deforestation, but more pervasive impacts, such as hunting, might increase. PMID:22912787</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9104E..02G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9104E..02G"><span>Hyperspectral forest monitoring and imaging implications</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Goodenough, David G.; Bannon, David</p> <p>2014-05-01</p> <p>The forest biome is vital to the health of the earth. Canada and the United States have a combined forest area of 4.68 Mkm2. The monitoring of these forest resources has become increasingly complex. Hyperspectral remote sensing can provide a wealth of improved information products to land managers to make more informed decisions. Research in this area has demonstrated that hyperspectral remote sensing can be used to create more accurate products for forest inventory (major forest species), forest health, foliar biochemistry, biomass, and aboveground carbon. Operationally there is a requirement for a mix of airborne and satellite approaches. This paper surveys some methods and results in hyperspectral sensing of forests and discusses the implications for space initiatives with hyperspectral sensing</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27551200','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27551200"><span>New Brazilian Cerambycidae from the Amazonian region (Coleoptera).</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Santos-Silva, Antonio; Galileo, Maria Helena M</p> <p>2016-01-01</p> <p>Three new species of Cerambycidae are described from the Brazilian Amazonian region: Psapharochrus bezarki (Lamiinae, Acanthoderini); Xenofrea ayri (Lamiinae, Xenofreini); and Mecometopus wappesi (Cerambycinae, Clytini). Mecometopus wappesi is added to a previous key.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.B33E..03H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.B33E..03H"><span>Assessing the impact of Amazonia logging with a new ecosystem model</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Huang, M.; Asner, G. P.; Keller, M.; Berry, J. A.; Bustamante, M. M.</p> <p>2006-12-01</p> <p>Old-growth Amazonian forests play a fundamental role in the global climate and carbon cycle. Land use in old- growth tropical forests contributes to the accumulation of CO2 in the atmosphere and can alter the hydrological cycle, locally, regionally, and globally. Although deforestation, largely for the conversion of land to food crops or pastures, is the major destructive force in tropical forests worldwide (Houghton et al., 2000), other forest disturbances such as the selective logging have also increased in frequency and extent. Selective logging causes widespread collateral damage to remaining trees, sub-canopy vegetation, and soils, with impacts on hydrological processes, erosion, fire, carbon storage, and plant and animal species. In this study, the impact of selective logging on the carbon budget of the Brazil Amazon region is assessed with a new 3-D version of the Carnegie-Ames-Stanford Approach (CASA) ecosystem model, which features: (1) an alternative way of estimating absorbed photosynthetically-active radiation (APAR) by taking advantage of new high-resolution maps of forest canopy gap fraction; (2) a pulse disturbance module to realistically modify the carbon pools after timber harvest; (3) a regrowth module considering changes in community composition; and (4) a radiative transfer module for charactering the dynamic 3-D light environment above the canopy and within gaps after logging. The model was calibrated and validated with field observations from the Large-scale Biosphere Atmosphere Experiment (LBA) and its sensitivity was evaluated with Monte Carlo simulations. The impacts of selected logging on regional carbon budget of the Brazilian Amazon were then assessed under different future climate change scenarios. Results from this study quantify the gross and net carbon storage effects of widespread logging practices throughout the Brazilian Amazon.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28707254','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28707254"><span>Effect of oil palm on the Plecoptera and Trichoptera (Insecta) assemblages in streams of eastern Amazon.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>de Paiva, Carina Kaory Sasahara; de Faria, Ana Paula Justino; Calvão, Lenize Batista; Juen, Leandro</p> <p>2017-08-01</p> <p>The production of oil palm is expected to increase in the Amazon region. However, expansion of oil palm plantation leads to significant changes in the physical structure of aquatic ecosystems, mainly through the reduction of riparian vegetation that is essential for aquatic biodiversity. Here, we evaluated the effects of oil palm on the physical habitat structure of Amazonian stream environments and assemblages of Plecoptera and Trichoptera (PT), both found in these streams. We compared streams sampled in oil palm plantations (n = 13) with natural forest areas ("reference" streams, n = 8), located in the eastern Amazon, Brazil. Our results showed that oil palm streams were more likely to be in close proximity to roads, had higher pH values, and higher amounts of fine substrate deposited in the channel than reference streams. Further, these environmental changes had important effects on the aquatic invertebrate assemblages, reducing the abundance and richness of PT. Nevertheless, the genera composition of the assemblages did not differ between reference and oil palm (PERMANOVA, pseudo-F (1,19) = 1.891; p = 0.111). We conclude that oil palm production has clear negative impacts on aquatic environments and PT assemblages in Amazonian streams. We recommend that oil palm producers invest more in planning of road networks to avoid the construction of roads near to the riparian vegetation. This planning can minimize impacts of oil palm production on aquatic systems in the Amazon.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1812696S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1812696S"><span>Sedimentology and hydrology of a well-preserved paleoriver systems with a series of dam-breach paleolakes at Moa Valles, Mars</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Salese, Francesco; Di Achille, Gaetano; Neesemann, Adrian; Ori, Gian Gabriele; Hauber, Ernst</p> <p>2016-04-01</p> <p>Moa Valles is a well-preserved paleodrainage system that is nearly 300-km-long and carved into ancient highland terrains west of Idaeus Fossae. The paleofluvial system apparently originated from fluidized ejecta blankets, and it consists of a series of dam-breach paleolakes with associated fan-shaped sedimentary deposits. This paleofluvial system shows a rich morphological record of hydrologic activity in the highlands of Mars. Based on crater counting the latter activity seems to be Amazonian in age (2.43 - 1.41 Ga). This work is based on a digital elevation model (DEM) derived from Context camera (CTX) and High Resolution Imaging Science Experiment (HiRISE) stereo images. Our goals are to (a) study the complex channel flow paths draining into Idaeus Fossae after forming a series of dam-breach paleolakes and to (b) investigate the origin and evolution of this valley system with its implications for climate and tectonic control. The first part of the system is characterized by many paleolakes, which are interconnected and drain eastward into Liberta crater, forming a complex and multilobate deltaic deposit exhibiting a well-developed channelized distributary pattern with evidence of switching on the delta plain. A breach area, consisting of three spillover channels, is present in the eastern part of the crater rim. These channels connect the Liberta crater to the eastward portion of the valley system, continuing toward Moa Valles with a complex pattern of anabranching channels that is more than 180-km-long. Our crater counting results and hydrological calculations of infilling and spillover discharges of the Liberta crater-lake suggest that the system is the result of an Early Amazonian water-rich environment that was likely sustained by relatively short fluvial events (<102 years), thereby supporting the hypotheses that water-related erosion might have been active on Mars (at least locally) during the Amazonian. The most important water source for the system could have been shallow ice melting triggered by impact craters. Indeed, the stratigraphic relationships between channels and crater ejecta show very clearly that the channels cut through the ejecta thus postdating them. The occurrence of relatively recent (likely Amazonian) hydrological activity supports the hypothesis that hydrological activity could have been possible, at least locally, after the Noachian-Hesperian boundary.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/48104','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/48104"><span>Functional groups show distinct differences in nitrogen cycling during early stand development: implications for forest management</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Doug P. Aubrey; David R. Coyle; Mark D. Coleman</p> <p>2012-01-01</p> <p>Background and aims Nutrient acquisition of forest stands is controlled by soil resource availability and belowground production, but tree species are rarely compared in this regard. Here, we examine ecological and management implications of nitrogen (N) dynamics during early forest stand development in productive commercial tree species with narrow (Populus...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006SPIE.6420E..20D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006SPIE.6420E..20D"><span>Predicting spatio-temporal failure in large scale observational and micro scale experimental systems</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>de las Heras, Alejandro; Hu, Yong</p> <p>2006-10-01</p> <p>Forecasting has become an essential part of modern thought, but the practical limitations still are manifold. We addressed future rates of change by comparing models that take into account time, and models that focus more on space. Cox regression confirmed that linear change can be safely assumed in the short-term. Spatially explicit Poisson regression, provided a ceiling value for the number of deforestation spots. With several observed and estimated rates, it was decided to forecast using the more robust assumptions. A Markov-chain cellular automaton thus projected 5-year deforestation in the Amazonian Arc of Deforestation, showing that even a stable rate of change would largely deplete the forest area. More generally, resolution and implementation of the existing models could explain many of the modelling difficulties still affecting forecasting.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18246280','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18246280"><span>[First Report of Lutzomyia França in the department of Guainía, Amazonian Colombia, and of Brumptomyia mesai Sherlock (Diptera: Psychodidae) in the Colombian Caribbean Coast].</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bejarano, Eduar E; Castro, Mirley; Pérez-Doria, Alveiro; Hernández-Oviedo, Ela; Vélez, Andrés; Vélez, Iván D</p> <p>2007-01-01</p> <p>This is the first record of the presence of the medically important genus Lutzomyia França in the Department of Guainía, Colombia. Sand flies were collected biting humans in the surroundings of the urban area of the Municipality of Inírida. Three Lutzomyia species were taxonomically identified as L. davisi (Root), L. olmeca bicolor Fairchild & Theodor, and L. antunesi (Coutinho). Additionally, Brumptomyia mesai Sherlock is cited for the first time in the Caribbean Coast of Colombia based on specimens collected with a modified CDC light trap in the Reserva Forestal Protectora Serranía de Coraza y Montes de María, Department of Sucre.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..1214289R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..1214289R"><span>Estimating Amazonian rainforest stability and the likelihood for large-scale forest dieback</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rammig, Anja; Thonicke, Kirsten; Jupp, Tim; Ostberg, Sebastian; Heinke, Jens; Lucht, Wolfgang; Cramer, Wolfgang; Cox, Peter</p> <p>2010-05-01</p> <p>Annually, tropical forests process approximately 18 Pg of carbon through respiration and photosynthesis - more than twice the rate of anthropogenic fossil fuel emissions. Current climate change may be transforming this carbon sink into a carbon source by changing forest structure and dynamics. Increasing temperatures and potentially decreasing precipitation and thus prolonged drought stress may lead to increasing physiological stress and reduced productivity for trees. Resulting decreases in evapotranspiration and therefore convective precipitation could further accelerate drought conditions and destabilize the tropical ecosystem as a whole and lead to an 'Amazon forest dieback'. The projected direction and intensity of climate change vary widely within the region and between different scenarios from climate models (GCMs). In the scope of a World Bank-funded study, we assessed the 24 General Circulation Models (GCMs) evaluated in the 4th Assessment Report of the Intergovernmental Panel on Climate Change (IPCC-AR4) with respect to their capability to reproduce present-day climate in the Amazon basin using a Bayesian approach. With this approach, greater weight is assigned to the models that simulate well the annual cycle of rainfall. We then use the resulting weightings to create probability density functions (PDFs) for future forest biomass changes as simulated by the Lund-Potsdam-Jena Dynamic Global Vegetation Model (LPJmL) to estimate the risk of potential Amazon rainforest dieback. Our results show contrasting changes in forest biomass throughout five regions of northern South America: If photosynthetic capacity and water use efficiency is enhanced by CO2, biomass increases across all five regions. However, if CO2-fertilisation is assumed to be absent or less important, then substantial dieback occurs in some scenarios and thus, the risk of forest dieback is considerably higher. Particularly affected are regions in the central Amazon basin. The range of potential biomass change arising from the weighting of rainfall patterns is smaller than the uncertainty arising from CO2-fertilisation effects, which highlights the importance of reducing the uncertainties in the direct effects of CO2 on tropical ecosystems. Strong biomass changes also imply changes in forest structure and thus, forest stability. Our results display shifts in forest composition from closed rainforest to more open forest or even shrubland. Our probability-based risk analysis could be used to advise regional forest protection.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhDT.......190K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhDT.......190K"><span>Regional hydro-climatic impacts of contemporary Amazonian deforestation</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Khanna, Jaya</p> <p></p> <p>More than 17% of the Amazon rainforest has been cleared in the past three decades triggering important climatological and societal impacts. This thesis is devoted to identifying and explaining the regional hydroclimatic impacts of this change employing multidecadal satellite observations and numerical simulations providing an integrated perspective on this topic. The climatological nature of this study motivated the implementation and application of a cloud detection technique to a new geostationary satellite dataset. The resulting sub daily, high spatial resolution, multidecadal time series facilitated the detection of trends and variability in deforestation triggered cloud cover changes. The analysis was complemented by satellite precipitation, reanalysis and ground based datasets and attribution with the variable resolution Ocean-Land-Atmosphere-Model. Contemporary Amazonian deforestation affects spatial scales of hundreds of kilometers. But, unlike the well-studied impacts of a few kilometers scale deforestation, the climatic response to contemporary, large scale deforestation is neither well observed nor well understood. Employing satellite datasets, this thesis shows a transition in the regional hydroclimate accompanying increasing scales of deforestation, with downwind deforested regions receiving 25% more and upwind deforested regions receiving 25% less precipitation from the deforested area mean. Simulations robustly reproduce these shifts when forced with increasing deforestation alone, suggesting a negligible role of large-scale decadal climate variability in causing the shifts. Furthermore, deforestation-induced surface roughness variations are found necessary to reproduce the observed spatial patterns in recent times illustrating the strong scale-sensitivity of the climatic response to Amazonian deforestation. This phenomenon, inconsequential during the wet season, is found to substantially affect the regional hydroclimate in the local dry and parts of transition seasons, hence occurring in atmospheric conditions otherwise less conducive to thermal convection. Evidence of this phenomenon is found at two large scale deforested areas considered in this thesis. Hence, the 'dynamical' mechanism, which affects the seasons most important for regional ecology, emerges as an impactful convective triggering mechanism. The phenomenon studied in this thesis provides context for thinking about the climate of a future, more patchily forested Amazonia, by articulating relationships between climate and spatial scales of deforestation.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3311550','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3311550"><span>A Macroecological Analysis of SERA Derived Forest Heights and Implications for Forest Volume Remote Sensing</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Brolly, Matthew; Woodhouse, Iain H.; Niklas, Karl J.; Hammond, Sean T.</p> <p>2012-01-01</p> <p>Individual trees have been shown to exhibit strong relationships between DBH, height and volume. Often such studies are cited as justification for forest volume or standing biomass estimation through remote sensing. With resolution of common satellite remote sensing systems generally too low to resolve individuals, and a need for larger coverage, these systems rely on descriptive heights, which account for tree collections in forests. For remote sensing and allometric applications, this height is not entirely understood in terms of its location. Here, a forest growth model (SERA) analyzes forest canopy height relationships with forest wood volume. Maximum height, mean, H100, and Lorey's height are examined for variability under plant number density, resource and species. Our findings, shown to be allometrically consistent with empirical measurements for forested communities world-wide, are analyzed for implications to forest remote sensing techniques such as LiDAR and RADAR. Traditional forestry measures of maximum height, and to a lesser extent H100 and Lorey's, exhibit little consistent correlation with forest volume across modeled conditions. The implication is that using forest height to infer volume or biomass from remote sensing requires species and community behavioral information to infer accurate estimates using height alone. SERA predicts mean height to provide the most consistent relationship with volume of the height classifications studied and overall across forest variations. This prediction agrees with empirical data collected from conifer and angiosperm forests with plant densities ranging between 102–106 plants/hectare and heights 6–49 m. Height classifications investigated are potentially linked to radar scattering centers with implications for allometry. These findings may be used to advance forest biomass estimation accuracy through remote sensing. Furthermore, Lorey's height with its specific relationship to remote sensing physics is recommended as a more universal indicator of volume when using remote sensing than achieved using either maximum height or H100. PMID:22457800</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22457800','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22457800"><span>A macroecological analysis of SERA derived forest heights and implications for forest volume remote sensing.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Brolly, Matthew; Woodhouse, Iain H; Niklas, Karl J; Hammond, Sean T</p> <p>2012-01-01</p> <p>Individual trees have been shown to exhibit strong relationships between DBH, height and volume. Often such studies are cited as justification for forest volume or standing biomass estimation through remote sensing. With resolution of common satellite remote sensing systems generally too low to resolve individuals, and a need for larger coverage, these systems rely on descriptive heights, which account for tree collections in forests. For remote sensing and allometric applications, this height is not entirely understood in terms of its location. Here, a forest growth model (SERA) analyzes forest canopy height relationships with forest wood volume. Maximum height, mean, H₁₀₀, and Lorey's height are examined for variability under plant number density, resource and species. Our findings, shown to be allometrically consistent with empirical measurements for forested communities world-wide, are analyzed for implications to forest remote sensing techniques such as LiDAR and RADAR. Traditional forestry measures of maximum height, and to a lesser extent H₁₀₀ and Lorey's, exhibit little consistent correlation with forest volume across modeled conditions. The implication is that using forest height to infer volume or biomass from remote sensing requires species and community behavioral information to infer accurate estimates using height alone. SERA predicts mean height to provide the most consistent relationship with volume of the height classifications studied and overall across forest variations. This prediction agrees with empirical data collected from conifer and angiosperm forests with plant densities ranging between 10²-10⁶ plants/hectare and heights 6-49 m. Height classifications investigated are potentially linked to radar scattering centers with implications for allometry. These findings may be used to advance forest biomass estimation accuracy through remote sensing. Furthermore, Lorey's height with its specific relationship to remote sensing physics is recommended as a more universal indicator of volume when using remote sensing than achieved using either maximum height or H₁₀₀.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70035665','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70035665"><span>Pollen-based biome reconstructions for Latin America at 0, 6000 and 18 000 radiocarbon years</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Marchant, R.; Harrison, S.P.; Hooghiemstra, H.; Markgraf, Vera; Van Boxel, J. H.; Ager, T.; Almeida, L.; Anderson, R.; Baied, C.; Behling, H.; Berrio, J.C.; Burbridge, R.; Bjorck, S.; Byrne, R.; Bush, M.B.; Cleef, A.M.; Duivenvoorden, J.F.; Flenley, J.R.; De Oliveira, P.; Van Geel, B.; Graf, K.J.; Gosling, W.D.; Harbele, S.; Van Der Hammen, T.; Hansen, B.C.S.; Horn, S.P.; Islebe, G.A.; Kuhry, P.; Ledru, M.-P.; Mayle, F.E.; Leyden, B.W.; Lozano-Garcia, S.; Melief, A.B.M.; Moreno, P.; Moar, N.T.; Prieto, A.; Van Reenen, G. B.; Salgado-Labouriau, M. L.; Schasignbitz, F.; Schreve-Brinkman, E. J.; Wille, M.</p> <p>2009-01-01</p> <p>The biomisation method is used to reconstruct Latin American vegetation at 6000±500 and 18 000±1000 radiocarbon years before present (14C yr BP) from pollen data. Tests using modern pollen data from 381 samples derived from 287 locations broadly reproduce potential natural vegetation. The strong temperature gradient associated with the Andes is recorded by a transition from high altitude cool grass/shrubland and cool mixed forest to mid-altitude cool temperate rain forest, to tropical dry, seasonal and rain forest at low altitudes. Reconstructed biomes from a number of sites do not match the potential vegetation due to local factors such as human impact, methodological artefacts and mechanisms of pollen representivity of the parent vegetation. <br><br> At 6000±500 14C yr BP 255 samples are analysed from 127 sites. Differences between the modern and the 6000±500 14C yr BP reconstruction are comparatively small. Patterns of change relative to the modern reconstruction are mainly to biomes characteristic of drier climate in the north of the region with a slight more mesic shift in the south. Cool temperate rain forest remains dominant in western South America. In northwestern South America a number of sites record transitions from tropical seasonal forest to tropical dry forest and tropical rain forest to tropical seasonal forest. Sites in Central America also show a change in biome assignment to more mesic vegetation, indicative of greater plant available moisture, e.g. on the Yucat??n peninsula sites record warm evergreen forest, replacing tropical dry forest and warm mixed forest presently recorded. <br><br> At 18 000±1000 14C yr BP 61 samples from 34 sites record vegetation that reflects a generally cool and dry environment. Cool grass/shrubland prevalent in southeast Brazil, Amazonian sites record tropical dry forest, warm temperate rain forest and tropical seasonal forest. Southernmost South America is dominated by cool grass/shrubland, a single site retains cool temperate rain forest indicating that forest was present at some locations at the LGM. Some sites in Central M??xico and lowland Colombia remain unchanged in their biome assignments, although the affinities that these sites have to different biomes do change between 18 000±1000 14C yr BP and present. The " unresponsive" nature of these sites results from their location and the impact of local edaphic influence.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.B11G0104C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.B11G0104C"><span>Tree Diametric Increment and Litterfall Production in an Eastern Amazonian Forest: the Role of Functional Groups</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Camargo, P. B. D.; Ferreira, M. L.; Oliveira Junior, R. C.; Saleska, S. R.</p> <p>2014-12-01</p> <p>Tree growth is a biotic variable of great importance in understanding the dynamics of tree communities and may be used as a tool in studies of biological or climate modeling. Some climate models predict more recurrent climate anomalies in this century, which may alter the functioning of tropical forests with serious structural and demographic implications. The present study aimed to evaluate the profile of tree growth and litterfall production in an eastern Amazon forest, which has suffered recent climatic disturbances. We contrasted different functional groups based on wood density (stem with 0.55; 0.56-0.7; >0.7 g cm-3), light availability (crown illumination index; high illuminated crown - IIC1 until shaded crown - IIC5), and, size class (trees 10-22.5; 22.6-35; 35.1-55; 55,1-90; >90 cm dbh). Tree diameter increment was monthly measured from November 2011 to September 2013 by using dendrometer bands installed on 850 individuals from different families. Litterfall was collected in 64 circular traps, oven dried and weighed, separated into leaves, twigs, reproductive parts and miscellaneous. During the rainy season the sampled trees had the highest rates of tree diametric increment. When analyzing the data by functional groups, large trees had faster growth, but when grouped by wood density, trees with wood density up to 0.55 and between 0.56 and 0.7 g cm-3 had the fastest rates of growth. When grouped by crown illumination index, trees exposed to higher levels of light grew more in comparison to partially shaded trees. Maximum daily air temperature and precipitation were the most important environmental variables in determining the diametric increment profile of the trees. Litterfall production was estimated to be 7.1 Mg ha-1.year-1 and showed a strong seasonal pattern, with dry season production being higher than in the rainy season. Leaves formed the largest fraction of the litterfall, followed by twigs, reproductive parts, and finally miscellaneous. These results show that the profile of tree diametric growth and litterfall production are recorded at close intervals in the preterit analyzes in the same study area and highlights the efficiency of functional groups in determining the tree growth profile.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUSM.H22A..02H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUSM.H22A..02H"><span>Observations On Some Upper Amazonian Wetlands of Southeastern Peru</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Householder, J. E.; Muttiah, R.; Khanal, S.</p> <p>2007-05-01</p> <p>Upper Amazonian wetlands represent little studied, poorly understood, and grossly under protected systems. Scientific investigation of Amazonian wetlands is in its infancy; nor is there much known about their ecological services. Regionally, wetlands form a ubiquitous and significant component of floodplain habitat fed by perennial springs as well as overland runoff. Locally, wetland vegetation forms bewilderingly complex vegetation mosaics that seem to be governed by local topography and hydrology. Drawing upon intensive field campaigns and remotely sensed imagery, we summarize the results and experiences gathered in wetlands of southeastern Peru.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25349419','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25349419"><span>Vegetation dynamics and rainfall sensitivity of the Amazon.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hilker, Thomas; Lyapustin, Alexei I; Tucker, Compton J; Hall, Forrest G; Myneni, Ranga B; Wang, Yujie; Bi, Jian; Mendes de Moura, Yhasmin; Sellers, Piers J</p> <p>2014-11-11</p> <p>We show that the vegetation canopy of the Amazon rainforest is highly sensitive to changes in precipitation patterns and that reduction in rainfall since 2000 has diminished vegetation greenness across large parts of Amazonia. Large-scale directional declines in vegetation greenness may indicate decreases in carbon uptake and substantial changes in the energy balance of the Amazon. We use improved estimates of surface reflectance from satellite data to show a close link between reductions in annual precipitation, El Niño southern oscillation events, and photosynthetic activity across tropical and subtropical Amazonia. We report that, since the year 2000, precipitation has declined across 69% of the tropical evergreen forest (5.4 million km(2)) and across 80% of the subtropical grasslands (3.3 million km(2)). These reductions, which coincided with a decline in terrestrial water storage, account for about 55% of a satellite-observed widespread decline in the normalized difference vegetation index (NDVI). During El Niño events, NDVI was reduced about 16.6% across an area of up to 1.6 million km(2) compared with average conditions. Several global circulation models suggest that a rise in equatorial sea surface temperature and related displacement of the intertropical convergence zone could lead to considerable drying of tropical forests in the 21st century. Our results provide evidence that persistent drying could degrade Amazonian forest canopies, which would have cascading effects on global carbon and climate dynamics.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26241204','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26241204"><span>Effects of Governance on Availability of Land for Agriculture and Conservation in Brazil.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sparovek, Gerd; Barretto, Alberto Giaroli de Oliveira Pereira; Matsumoto, Marcelo; Berndes, Göran</p> <p>2015-09-01</p> <p>The 2012 revision of the Brazilian Forest Act changed the relative importance of private and public governance for nature conservation and agricultural production. We present a spatially explicit land-use model for Brazilian agricultural production and nature conservation that considers the spatial distribution of agricultural land suitability, technological and management options, legal command, and control frameworks including the Atlantic Forest Law, the revised Forest Act, and the Amazonian land-titling, "Terra Legal," and also market-driven land use regulations. The model is used to analyze land use allocation under three scenarios with varying priorities among agricultural production and environmental protection objectives. In all scenarios, the legal command and control frameworks were the most important determinants of conservation outcomes, protecting at least 80% of the existing natural vegetation. Situations where such frameworks are not expected to be effective can be identified and targeted for additional conservation (beyond legal requirements) through voluntary actions or self-regulation in response to markets. All scenarios allow for a substantial increase in crop production, using an area 1.5-2.7 times the current cropland area, with much of new cropland occurring on current pastureland. Current public arrangements that promote conservation can, in conjunction with voluntary schemes on private lands where conversion to agriculture is favored, provide important additional nature conservation without conflicting with national agricultural production objectives.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5880039','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5880039"><span>Scaling estimates of vegetation structure in Amazonian tropical forests using multi-angle MODIS observations</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>de Moura, Yhasmin Mendes; Hilker, Thomas; Goncalves, Fabio Guimarães; Galvão, Lênio Soares; dos Santos, João Roberto; Lyapustin, Alexei; Maeda, Eduardo Eiji; de Jesus Silva, Camila Valéria</p> <p>2018-01-01</p> <p>Detailed knowledge of vegetation structure is required for accurate modelling of terrestrial ecosystems, but direct measurements of the three dimensional distribution of canopy elements, for instance from LiDAR, are not widely available. We investigate the potential for modelling vegetation roughness, a key parameter for climatological models, from directional scattering of visible and near-infrared (NIR) reflectance acquired from NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS). We compare our estimates across different tropical forest types to independent measures obtained from: (1) airborne laser scanning (ALS), (2) spaceborne Geoscience Laser Altimeter System (GLAS)/ICESat, and (3) the spaceborne SeaWinds/QSCAT. Our results showed linear correlation between MODIS-derived anisotropy to ALS-derived entropy (r2= 0.54, RMSE=0.11), even in high biomass regions. Significant relationships were also obtained between MODIS-derived anisotropy and GLAS-derived entropy (0.52≤ r2≤ 0.61; p<0.05), with similar slopes and offsets found throughout the season, and RMSE between 0.26 and 0.30 (units of entropy). The relationships between the MODIS-derived anisotropy and backscattering measurements (σ0) from SeaWinds/QuikSCAT presented an r2 of 0.59 and a RMSE of 0.11. We conclude that multi-angular MODIS observations are suitable to extrapolate measures of canopy entropy across different forest types, providing additional estimates of vegetation structure in the Amazon. PMID:29618964</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150011447','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150011447"><span>Vegetation Dynamics and Rainfall Sensitivity of the Amazon</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hilker, Thomas; Lyapustin, Alexei I.; Tucker, Compton J.; Hall, Forrest G.; Myneni, Ranga B.; Wang, Yujie; Bi, Jian; Mendes de Moura, Yhasmin; Sellers, Piers J.</p> <p>2014-01-01</p> <p>We show that the vegetation canopy of the Amazon rainforest is highly sensitive to changes in precipitation patterns and that reduction in rainfall since 2000 has diminished vegetation greenness across large parts of Amazonia. Large-scale directional declines in vegetation greenness may indicate decreases in carbon uptake and substantial changes in the energy balance of the Amazon. We use improved estimates of surface reflectance from satellite data to show a close link between reductions in annual precipitation, El Nino southern oscillation events, and photosynthetic activity across tropical and subtropical Amazonia. We report that, since the year 2000, precipitation has declined across 69% of the tropical evergreen forest (5.4 million sq km) and across 80% of the subtropical grasslands (3.3 million sq km). These reductions, which coincided with a decline in terrestrial water storage, account for about 55% of a satellite-observed widespread decline in the normalized difference vegetation index (NDVI). During El Nino events, NDVI was reduced about 16.6% across an area of up to 1.6 million sq km compared with average conditions. Several global circulation models suggest that a rise in equatorial sea surface temperature and related displacement of the intertropical convergence zone could lead to considerable drying of tropical forests in the 21st century. Our results provide evidence that persistent drying could degrade Amazonian forest canopies, which would have cascading effects on global carbon and climate dynamics.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4156456','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4156456"><span>Malaria in the state of Rio de Janeiro, Brazil, an Atlantic Forest area: an assessment using the health surveillance service</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Miguel, Renata Bortolasse; Peiter, Paulo Cesar; de Albuquerque, Hermano; Coura, José Rodrigues; Moza, Patrícia Ganzenmüller; Costa, Anielle de Pina; Brasil, Patricia; Suárez-Mutis, Martha Cecília</p> <p>2014-01-01</p> <p>The lethality of malaria in the extra-Amazonian region is more than 70 times higher than in Amazonia itself. Recently, several studies have shown that autochthonous malaria is not a rare event in the Brazilian southeastern states in the Atlantic Forest biome. Information about autochthonous malaria in the state of Rio de Janeiro (RJ) is scarce. This study aims to assess malaria cases reported to the Health Surveillance System of the State of Rio de Janeiro between 2000-2010. An average of 90 cases per year had parasitological malaria confirmation by thick smear. The number of malaria notifications due to Plasmodium falciparum increased over time. Imported cases reported during the period studied were spread among 51% of the municipalities (counties) of the state. Only 35 cases (4.3%) were autochthonous, which represents an average of 3.8 new cases per year. Eleven municipalities reported autochthonous cases; within these, six could be characterised as areas of residual or new foci of malaria from the Atlantic Forest system. The other 28 municipalities could become receptive for transmission reintroduction. Cases occurred during all periods of the year, but 62.9% of cases were in the first semester of each year. Assessing vulnerability and receptivity conditions and vector ecology is imperative to establish the real risk of malaria reintroduction in RJ. PMID:25185004</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ACP....18.3083O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ACP....18.3083O"><span>Nighttime wind and scalar variability within and above an Amazonian canopy</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Oliveira, Pablo E. S.; Acevedo, Otávio C.; Sörgel, Matthias; Tsokankunku, Anywhere; Wolff, Stefan; Araújo, Alessandro C.; Souza, Rodrigo A. F.; Sá, Marta O.; Manzi, Antônio O.; Andreae, Meinrat O.</p> <p>2018-03-01</p> <p>Nocturnal turbulent kinetic energy (TKE) and fluxes of energy, CO2 and O3 between the Amazon forest and the atmosphere are evaluated for a 20-day campaign at the Amazon Tall Tower Observatory (ATTO) site. The distinction of these quantities between fully turbulent (weakly stable) and intermittent (very stable) nights is discussed. Spectral analysis indicates that low-frequency, nonturbulent fluctuations are responsible for a large portion of the variability observed on intermittent nights. In these conditions, the low-frequency exchange may dominate over the turbulent transfer. In particular, we show that within the canopy most of the exchange of CO2 and H2O happens on temporal scales longer than 100 s. At 80 m, on the other hand, the turbulent fluxes are almost absent in such very stable conditions, suggesting a boundary layer shallower than 80 m. The relationship between TKE and mean winds shows that the stable boundary layer switches from the very stable to the weakly stable regime during intermittent bursts of turbulence. In general, fluxes estimated with long temporal windows that account for low-frequency effects are more dependent on the stability over a deeper layer above the forest than they are on the stability between the top of the canopy and its interior, suggesting that low-frequency processes are controlled over a deeper layer above the forest.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/54163','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/54163"><span>Diversity in forest management to reduce wildfire losses: implications for resilience</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Susan Charnley; Thomas A. Spies; Ana M. G. Barros; Eric M. White; Keith A. Olsen</p> <p>2017-01-01</p> <p>This study investigates how federal, state, and private corporate forest owners in a fire-prone landscape of southcentral Oregon manage their forests to reduce wildfire hazard and loss to high-severity wildfire. We evaluate the implications of our findings for concepts of socialâecological resilience. Using interview data, we found a high degree of "response...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4978004','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4978004"><span>New Brazilian Cerambycidae from the Amazonian region (Coleoptera)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Santos-Silva, Antonio; Galileo, Maria Helena M.</p> <p>2016-01-01</p> <p>Abstract Three new species of Cerambycidae are described from the Brazilian Amazonian region: Psapharochrus bezarki (Lamiinae, Acanthoderini); Xenofrea ayri (Lamiinae, Xenofreini); and Mecometopus wappesi (Cerambycinae, Clytini). Mecometopus wappesi is added to a previous key. PMID:27551200</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3329437','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3329437"><span>Proliferation of Hydroelectric Dams in the Andean Amazon and Implications for Andes-Amazon Connectivity</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Finer, Matt; Jenkins, Clinton N.</p> <p>2012-01-01</p> <p>Due to rising energy demands and abundant untapped potential, hydropower projects are rapidly increasing in the Neotropics. This is especially true in the wet and rugged Andean Amazon, where regional governments are prioritizing new hydroelectric dams as the centerpiece of long-term energy plans. However, the current planning for hydropower lacks adequate regional and basin-scale assessment of potential ecological impacts. This lack of strategic planning is particularly problematic given the intimate link between the Andes and Amazonian flood plain, together one of the most species rich zones on Earth. We examined the potential ecological impacts, in terms of river connectivity and forest loss, of the planned proliferation of hydroelectric dams across all Andean tributaries of the Amazon River. Considering data on the full portfolios of existing and planned dams, along with data on roads and transmission line systems, we developed a new conceptual framework to estimate the relative impacts of all planned dams. There are plans for 151 new dams greater than 2 MW over the next 20 years, more than a 300% increase. These dams would include five of the six major Andean tributaries of the Amazon. Our ecological impact analysis classified 47% of the potential new dams as high impact and just 19% as low impact. Sixty percent of the dams would cause the first major break in connectivity between protected Andean headwaters and the lowland Amazon. More than 80% would drive deforestation due to new roads, transmission lines, or inundation. We conclude with a discussion of three major policy implications of these findings. 1) There is a critical need for further strategic regional and basin scale evaluation of dams. 2) There is an urgent need for a strategic plan to maintain Andes-Amazon connectivity. 3) Reconsideration of hydropower as a low-impact energy source in the Neotropics. PMID:22529979</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22529979','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22529979"><span>Proliferation of hydroelectric dams in the Andean Amazon and implications for Andes-Amazon connectivity.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Finer, Matt; Jenkins, Clinton N</p> <p>2012-01-01</p> <p>Due to rising energy demands and abundant untapped potential, hydropower projects are rapidly increasing in the Neotropics. This is especially true in the wet and rugged Andean Amazon, where regional governments are prioritizing new hydroelectric dams as the centerpiece of long-term energy plans. However, the current planning for hydropower lacks adequate regional and basin-scale assessment of potential ecological impacts. This lack of strategic planning is particularly problematic given the intimate link between the Andes and Amazonian flood plain, together one of the most species rich zones on Earth. We examined the potential ecological impacts, in terms of river connectivity and forest loss, of the planned proliferation of hydroelectric dams across all Andean tributaries of the Amazon River. Considering data on the full portfolios of existing and planned dams, along with data on roads and transmission line systems, we developed a new conceptual framework to estimate the relative impacts of all planned dams. There are plans for 151 new dams greater than 2 MW over the next 20 years, more than a 300% increase. These dams would include five of the six major Andean tributaries of the Amazon. Our ecological impact analysis classified 47% of the potential new dams as high impact and just 19% as low impact. Sixty percent of the dams would cause the first major break in connectivity between protected Andean headwaters and the lowland Amazon. More than 80% would drive deforestation due to new roads, transmission lines, or inundation. We conclude with a discussion of three major policy implications of these findings. 1) There is a critical need for further strategic regional and basin scale evaluation of dams. 2) There is an urgent need for a strategic plan to maintain Andes-Amazon connectivity. 3) Reconsideration of hydropower as a low-impact energy source in the Neotropics.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3638427','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3638427"><span>Effects of high-frequency understorey fires on woody plant regeneration in southeastern Amazonian forests</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Balch, Jennifer K.; Massad, Tara J.; Brando, Paulo M.; Nepstad, Daniel C.; Curran, Lisa M.</p> <p>2013-01-01</p> <p>Anthropogenic understorey fires affect large areas of tropical forest, yet their effects on woody plant regeneration post-fire remain poorly understood. We examined the effects of repeated experimental fires on woody stem (less than 1 cm at base) mortality, recruitment, species diversity, community similarity and regeneration mode (seed versus sprout) in Mato Grosso, Brazil. From 2004 to 2010, forest plots (50 ha) were burned twice (B2) or five times (B5), and compared with an unburned control (B0). Stem density recovered within a year after the first burn (initial density: 12.4–13.2 stems m−2), but after 6 years, increased mortality and decreased regeneration—primarily of seedlings—led to a 63 per cent and 85 per cent reduction in stem density in B2 and B5, respectively. Seedlings and sprouts across plots in 2010 displayed remarkable community similarity owing to shared abundant species. Although the dominant surviving species were similar across plots, a major increase in sprouting occurred—almost three- and fourfold greater in B2 and B5 than in B0. In B5, 29 species disappeared and were replaced by 11 new species often present along fragmented forest edges. By 2010, the annual burn regime created substantial divergence between the seedling community and the initial adult tree community (greater than or equal to 20 cm dbh). Increased droughts and continued anthropogenic ignitions associated with frontier land uses may promote high-frequency fire regimes that may substantially alter regeneration and therefore successional processes. PMID:23610167</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24558378','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24558378"><span>Variability of carbon and water fluxes following climate extremes over a tropical forest in southwestern Amazonia.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zeri, Marcelo; Sá, Leonardo D A; Manzi, Antônio O; Araújo, Alessandro C; Aguiar, Renata G; von Randow, Celso; Sampaio, Gilvan; Cardoso, Fernando L; Nobre, Carlos A</p> <p>2014-01-01</p> <p>The carbon and water cycles for a southwestern Amazonian forest site were investigated using the longest time series of fluxes of CO2 and water vapor ever reported for this site. The period from 2004 to 2010 included two severe droughts (2005 and 2010) and a flooding year (2009). The effects of such climate extremes were detected in annual sums of fluxes as well as in other components of the carbon and water cycles, such as gross primary production and water use efficiency. Gap-filling and flux-partitioning were applied in order to fill gaps due to missing data, and errors analysis made it possible to infer the uncertainty on the carbon balance. Overall, the site was found to have a net carbon uptake of ≈5 t C ha(-1) year(-1), but the effects of the drought of 2005 were still noticed in 2006, when the climate disturbance caused the site to become a net source of carbon to the atmosphere. Different regions of the Amazon forest might respond differently to climate extremes due to differences in dry season length, annual precipitation, species compositions, albedo and soil type. Longer time series of fluxes measured over several locations are required to better characterize the effects of climate anomalies on the carbon and water balances for the whole Amazon region. Such valuable datasets can also be used to calibrate biogeochemical models and infer on future scenarios of the Amazon forest carbon balance under the influence of climate change.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15895023','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15895023"><span>Prevalence of pterygium and cataract in indigenous populations of the Brazilian Amazon rain forest.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Paula, J S; Thorn, F; Cruz, A A V</p> <p>2006-05-01</p> <p>To compare the prevalence of pterygium and cataract in four indigenous populations of the Brazilian Amazonian rain forest (Arawak, Tukano, Maku, and Yanomami) with different ethnic and social behaviour backgrounds. A cross-sectional pterygium and cataract survey was performed in 624 adult Indians of the Brazilian rain forest belonging to four different ethnic groups. The Indians were classified according to their social behaviour in two groups: Arawak and Tukano (group 1) and Maku and Yanomami (group 2). Slit-lamp biomicroscopy was employed to examine the entire sample. All subjects were classified as 1 or 0 according to the presence or absence pterygium and cataract. Sex and age were also recorded. chi(2)-tests revealed that the prevalence of pterygium and cataract differed significantly between groups 1 and 2. For pterygia: 36.6% (97/265) and 5.0% (18/359), respectively (chi(2)=101.2, P<0.0001), and for cataracts: 24.5% (65/265) and 13.7% (49/359) respectively (chi(2)=12.09, P=0.0005). Gender was not associated with pterygium (P=0.1326) and cataract (P=0.2263) in both groups. Elderly subjects showed a significantly higher prevalence of cataract (P<0.0001). The prevalence of pterygia did not increase with age (P=0.8079) in both groups. Indians of group 1 have higher prevalence of pterygia and cataract than Indians of group 2. Social behaviour, especially the rate of sun exposure, appears to be the main factor for the different rates of pterygium and cataract displayed by these indigenous people of the Brazilian rain forest.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24830756','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24830756"><span>Variations in evapotranspiration and climate for an Amazonian semi-deciduous forest over seasonal, annual, and El Niño cycles.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vourlitis, George L; de Souza Nogueira, José; de Almeida Lobo, Francisco; Pinto, Osvaldo Borges</p> <p>2015-02-01</p> <p>Tropical forests exchange large amounts of water and energy with the atmosphere and are important in controlling regional and global climate; however, climate and evaportranspiration (E) vary significantly across multiple time scales. To better understand temporal patterns in E and climate, we measured the energy balance and meteorology of a semi-deciduous forest in the rainforest-savanna ecotone of northern Mato Grosso, Brazil, over a 7-year period and analyzed regional climate patterns over a 16-year period. Spectral analysis revealed that E and local climate exhibited consistent cycles over annual, seasonal, and weekly time scales. Annual and seasonal cycles were also apparent in the regional monthly rainfall and humidity time series, and a cycle on the order of 3-5.5 years was also apparent in the regional air temperature time series, which is coincident with the average return interval of El Niño. Annual rates of E were significantly affected by the 2002 El Niño. Prior to this event, annual E was on average 1,011 mm/year and accounted for 52% of the annual rainfall, while after, annual E was 931 mm/year and accounted for 42% of the annual rainfall. Our data also suggest that E declined significantly over the 7-year study period while air temperature significantly increased, which was coincident with a long-term, regional warming and drying trend. These results suggest that drought and warming induced by El Niño and/or climate change cause declines in E for semi-deciduous forests of the southeast Amazon Basin.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015IJBm...59..217V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015IJBm...59..217V"><span>Variations in evapotranspiration and climate for an Amazonian semi-deciduous forest over seasonal, annual, and El Niño cycles</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vourlitis, George L.; de Souza Nogueira, José; de Almeida Lobo, Francisco; Pinto, Osvaldo Borges</p> <p>2015-02-01</p> <p>Tropical forests exchange large amounts of water and energy with the atmosphere and are important in controlling regional and global climate; however, climate and evaportranspiration ( E) vary significantly across multiple time scales. To better understand temporal patterns in E and climate, we measured the energy balance and meteorology of a semi-deciduous forest in the rainforest-savanna ecotone of northern Mato Grosso, Brazil, over a 7-year period and analyzed regional climate patterns over a 16-year period. Spectral analysis revealed that E and local climate exhibited consistent cycles over annual, seasonal, and weekly time scales. Annual and seasonal cycles were also apparent in the regional monthly rainfall and humidity time series, and a cycle on the order of 3-5.5 years was also apparent in the regional air temperature time series, which is coincident with the average return interval of El Niño. Annual rates of E were significantly affected by the 2002 El Niño. Prior to this event, annual E was on average 1,011 mm/year and accounted for 52 % of the annual rainfall, while after, annual E was 931 mm/year and accounted for 42 % of the annual rainfall. Our data also suggest that E declined significantly over the 7-year study period while air temperature significantly increased, which was coincident with a long-term, regional warming and drying trend. These results suggest that drought and warming induced by El Niño and/or climate change cause declines in E for semi-deciduous forests of the southeast Amazon Basin.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016QSRv..132..114B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016QSRv..132..114B"><span>Long-term man-environment interactions in the Bolivian Amazon: 8000 years of vegetation dynamics</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brugger, Sandra O.; Gobet, Erika; van Leeuwen, Jacqueline F. N.; Ledru, Marie-Pierre; Colombaroli, Daniele; van der Knaap, W. O.; Lombardo, Umberto; Escobar-Torrez, Katerine; Finsinger, Walter; Rodrigues, Leonor; Giesche, Alena; Zarate, Modesto; Veit, Heinz; Tinner, Willy</p> <p>2016-01-01</p> <p>Only few studies documenting the vegetation history of the Llanos de Moxos, one of the largest seasonally flooded wetland areas in South America, are available and little is known about the environmental impact of pre-Columbian settlements. We use radiocarbon-dated terrestrial plant macrofossils to establish a sound chronology and palynological analyses to reconstruct the vegetation and fire history of the Lago Rogaguado area. The sedimentary pollen and spore record suggests that wetland and wooded savannah (Cerrado) environments occurred around the lake between 8100 and 5800 cal BP. Fire activity was high during this period and was probably connected to the dry Cerrado environments. The pollen evidence suggests early plant cultivation (Zea mays, Annonaceae and Cucurbitaceae) from 6500 cal BP onwards, which is significantly earlier than hitherto assumed for Amazonia. Gallery forests expanded after 5800 cal BP, when fire activity strongly declined. Forest expansion intensified around 2800 cal BP and continued until 2000 cal BP, when forest cover reached its maximum and fire activity its minimum. The late-Holocene forest expansion to the south and the decrease of fire activity may have resulted from a climatic shift to moister conditions (possibly a shorter dry season). New crops (e.g. Avena-type) or adventive plants (e.g. Rumex acetosella-type) document the impact of European economies after ca. 500 cal BP. Land use intensity remained rather stable over the most recent centuries, arguing against a collapse of settlements in response to the arrival of Europeans, as reconstructed from other Amazonian pollen records.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22750114','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22750114"><span>Large-scale phylogeography of the disjunct Neotropical tree species Schizolobium parahyba (Fabaceae-Caesalpinioideae).</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Turchetto-Zolet, Andreia C; Cruz, Fernanda; Vendramin, Giovanni G; Simon, Marcelo F; Salgueiro, Fabiano; Margis-Pinheiro, Marcia; Margis, Rogerio</p> <p>2012-10-01</p> <p>Neotropical rainforests exhibit high levels of endemism and diversity. Although the evolutionary genetics of plant diversification has garnered increased interest, phylogeographic studies of widely distributed species remain scarce. Here we describe chloroplast and nuclear variation patterns in Schizolobium parahyba (Fabaceae), a widespread tree in Neotropical rainforests that harbor two varieties with a disjunct distribution. Chloroplast and nuclear sequence analyses yielded 21 and 4 haplotypes, respectively. Two genetic diversity centers that correlate with the two known varieties were identified: the Southeastern Atlantic forest and the Amazonian basin. In contrast, the populations from southern and northeastern Atlantic forests and Andean-Central American forests exhibited low levels of genetic diversity and divergent haplotypes, likely related to historical processes that impact the flora and fauna in these regions, such as a founder's effect after dispersion and demographic expansion. Phylogeographic and demographic patterns suggest that episodes of genetic isolation and dispersal events have shaped the evolutionary history for this species, and different patterns have guided the evolution of S. parahyba. Moreover, the results of this study suggest that the dry corridor formed by Cerrado and Caatinga ecoregions and the Andean uplift acted as barriers to this species' gene flow, a picture that may be generalized to most of the plant biodiversity tropical woodlands and forests. These results also reinforce the importance of evaluating multiple genetic markers for a more comprehensive understanding of population structure and history. Our results provide insight into the conservation efforts and ongoing work on the genetics of population divergence and speciation in these Neotropical rainforests. Copyright © 2012 Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3928111','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3928111"><span>Variability of Carbon and Water Fluxes Following Climate Extremes over a Tropical Forest in Southwestern Amazonia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zeri, Marcelo; Sá, Leonardo D. A.; Manzi, Antônio O.; Araújo, Alessandro C.; Aguiar, Renata G.; von Randow, Celso; Sampaio, Gilvan; Cardoso, Fernando L.; Nobre, Carlos A.</p> <p>2014-01-01</p> <p>The carbon and water cycles for a southwestern Amazonian forest site were investigated using the longest time series of fluxes of CO2 and water vapor ever reported for this site. The period from 2004 to 2010 included two severe droughts (2005 and 2010) and a flooding year (2009). The effects of such climate extremes were detected in annual sums of fluxes as well as in other components of the carbon and water cycles, such as gross primary production and water use efficiency. Gap-filling and flux-partitioning were applied in order to fill gaps due to missing data, and errors analysis made it possible to infer the uncertainty on the carbon balance. Overall, the site was found to have a net carbon uptake of ≈5 t C ha−1 year−1, but the effects of the drought of 2005 were still noticed in 2006, when the climate disturbance caused the site to become a net source of carbon to the atmosphere. Different regions of the Amazon forest might respond differently to climate extremes due to differences in dry season length, annual precipitation, species compositions, albedo and soil type. Longer time series of fluxes measured over several locations are required to better characterize the effects of climate anomalies on the carbon and water balances for the whole Amazon region. Such valuable datasets can also be used to calibrate biogeochemical models and infer on future scenarios of the Amazon forest carbon balance under the influence of climate change. PMID:24558378</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=jungle&pg=4&id=EJ037688','ERIC'); return false;" href="https://eric.ed.gov/?q=jungle&pg=4&id=EJ037688"><span>A Bilingual Experiment in the Amazonian Jungle of Peru</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Wise, Mary Ruth</p> <p>1971-01-01</p> <p>In the Amazonian jungle of Peru 240 Indian leaders representing 20 different South American Indian language groups are successfully teaching their own people to read and write, first in their mother tongue and then in Spanish. (Author/EB)</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ACPD...1423995H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ACPD...1423995H"><span>Evaluation of MEGAN-CLM parameter sensitivity to predictions of isoprene emissions from an Amazonian rainforest</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Holm, J. A.; Jardine, K.; Guenther, A. B.; Chambers, J. Q.; Tribuzy, E.</p> <p>2014-09-01</p> <p>Tropical trees are known to be large emitters of biogenic volatile organic compounds (BVOC), accounting for up to 75% of the global isoprene budget. Once in the atmosphere, these compounds influence multiple processes associated with air quality and climate. However, uncertainty in biogenic emissions is two-fold, (1) the environmental controls over isoprene emissions from tropical forests remain highly uncertain; and (2) our ability to accurately represent these environmental controls within models is lacking. This study evaluated the biophysical parameters that drive the global Model of Emissions of Gases and Aerosols from Nature (MEGAN) embedded in a biogeochemistry land surface model, the Community Land Model (CLM), with a focus on isoprene emissions from an Amazonian forest. Upon evaluating the sensitivity of 19 parameters in CLM that currently influence isoprene emissions by using a Monte Carlo analysis, up to 61% of the uncertainty in mean isoprene emissions was caused by the uncertainty in the parameters related to leaf temperature. The eight parameters associated with photosynthetic active radiation (PAR) contributed in total to only 15% of the uncertainty in mean isoprene emissions. Leaf temperature was strongly correlated with isoprene emission activity (R2 = 0.89). However, when compared to field measurements in the Central Amazon, CLM failed to capture the upper 10-14 °C of leaf temperatures throughout the year (i.e., failed to represent ~32 to 46 °C), and the spread observed in field measurements was not representative in CLM. This is an important parameter to accurately simulate due to the non-linear response of emissions to temperature. MEGAN-CLM 4.0 overestimated isoprene emissions by 60% for a Central Amazon forest (5.7 mg m-2 h-1 vs. 3.6 mg m-2 h-1), but due to reductions in leaf area index (LAI) by 28% in MEGAN-CLM 4.5 isoprene emissions were within 7% of observed data (3.8 mg m-2 h-1). When a slight adjustment to leaf temperature was made to match observations, isoprene emissions increased 24%, up to 4.8 mg m-2 h-1. Air temperatures are very likely to increase in tropical regions as a result of human induced climate change. Reducing the uncertainty of leaf temperature in BVOC algorithms, as well as improving the accuracy of replicating leaf temperature output in land surface models is warranted in order to improve estimations of tropical BVOC emissions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26329116','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26329116"><span>Aging Perceptions in Tsimane' Amazonian Forager-Farmers Compared With Two Industrialized Societies.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sorokowski, Piotr; Sorokowska, Agnieszka; Frackowiak, Tomasz; Löckenhoff, Corinna E</p> <p>2017-07-01</p> <p>Cross-cultural studies suggest that aging attitudes show some variation across societies, but this evidence is mostly drawn from industrialized settings. The limited research record on pre-industrial societies is largely qualitative in nature. The present study targeted this gap by adapting an existing multidimensional measure of aging attitudes for use in traditional populations and administering it to samples from one traditional society and two industrialized societies. We administered the adapted multidimensional measure of aging attitudes to samples from one traditional society (Tsimane' Amazonian forager-farmers in Bolivia, n = 90) and two industrialized societies (the United States, n = 91, and Poland, n = 100). Across societies, aging perceptions were more favorable for respect and wisdom than for other domains of functioning, and women were perceived to be aging less favorably. Further, the Tsimane' reported more positive aging perceptions than the U.S. and Polish samples, especially with regard to memory functioning. Within the Tsimane' sample, there was no evidence of an influence of acculturation on aging perceptions. The present study contributed to our understanding of cross-cultural differences in aging attitudes. Theoretical implications and directions for future research are discussed. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2292638','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2292638"><span>Nutrition or Detoxification: Why Bats Visit Mineral Licks of the Amazonian Rainforest</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Voigt, Christian C.; Capps, Krista A.; Dechmann, Dina K. N.; Michener, Robert H.; Kunz, Thomas H.</p> <p>2008-01-01</p> <p>Many animals in the tropics of Africa, Asia and South America regularly visit so-called salt or mineral licks to consume clay or drink clay-saturated water. Whether this behavior is used to supplement diets with locally limited nutrients or to buffer the effects of toxic secondary plant compounds remains unclear. In the Amazonian rainforest, pregnant and lactating bats are frequently observed and captured at mineral licks. We measured the nitrogen isotope ratio in wing tissue of omnivorous short-tailed fruit bats, Carollia perspicillata, and in an obligate fruit-eating bat, Artibeus obscurus, captured at mineral licks and at control sites in the rainforest. Carollia perspicillata with a plant-dominated diet were more often captured at mineral licks than individuals with an insect-dominated diet, although insects were more mineral depleted than fruits. In contrast, nitrogen isotope ratios of A. obscurus did not differ between individuals captured at mineral lick versus control sites. We conclude that pregnant and lactating fruit-eating bats do not visit mineral licks principally for minerals, but instead to buffer the effects of secondary plant compounds that they ingest in large quantities during periods of high energy demand. These findings have potential implications for the role of mineral licks for mammals in general, including humans. PMID:18431492</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/21380','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/21380"><span>Forest and water relationships: hydrologic implications of forestation campaigns in China</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Ge Sun; Guoyi Zhou; Zhiqiang Zhang; Xiaohua Wei; Steven G. McNulty; James Vose</p> <p>2005-01-01</p> <p>Reforestation and afforestation (referred to forestation thereafter) campaigns in the past two decades have resulted in great increases in both forest land area and forest ecosystem productivity in China. Although the ecological benefits of forests are well accepted, the hydrologic consequences of man-made forests by forestation are unclear. Debate and confusion on the...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.B21F0530L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.B21F0530L"><span>AmazonFACE: Assessing the Effects of Increasing Atmospheric CO2 on the Resilience of the Amazon Forest through Integrative Model-Experiment Research</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lapola, D. M.</p> <p>2015-12-01</p> <p>The existence, magnitude and duration of a supposed "CO2 fertilization" effect in tropical forests remains largely undetermined, despite being suggested for nearly 20 years as a key knowledge gap for understanding the future resilience of Amazonian forests and its impact on the global carbon cycle. Reducing this uncertainty is critical for assessing the future of the Amazon region as well as its vulnerability to climate change. The AmazonFACE (Free-Air CO2 Enrichment) research program is an integrated model-experiment initiative of unprecedented scope in an old-growth Amazon forest near Manaus, Brazil - the first of its kind in tropical forest. The experimental treatment will simulate an atmospheric CO2 concentration [CO2] of the future in order to address the question: "How will rising atmospheric CO2 affect the resilience of the Amazon forest, the biodiversity it harbors, and the ecosystem services it provides, in light of projected climatic changes?" AmazonFACE is divided into three phases: (I) pre-experimental ecological characterization of the research site; (II) pilot experiment comprised of two 30-m diameter plots, with one treatment plot maintained at elevated [CO2] (ambient +200 ppmv), and the other control plot at ambient [CO2]; and (III) a fully-replicated long-term experiment comprised of four pairs of control/treatment FACE plots maintained for 10 years. A team of scientists from Brazil, USA, Australia and Europe will employ state-of-the-art methods to study the forest inside these plots in terms of carbon metabolism and cycling, water use, nutrient cycling, forest community composition, and interactions with environmental stressors. All project phases also encompass ecosystem-modeling activities in a way such that models provide hypothesis to be verified in the experiment, which in turn will feed models to ultimately produce more accurate projections of the environment. Resulting datasets and analyses will be a valuable resource for a broad community, especially ecosystem and climate modelers, and policy-makers.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1817882L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1817882L"><span>The AmazonFACE research program: assessing the effects of increasing atmospheric CO2 on the ecology and resilience of the Amazon forest</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lapola, David; Quesada, Carlos; Norby, Richard; Araújo, Alessandro; Domingues, Tomas; Hartley, Iain; Kruijt, Bart; Lewin, Keith; Meir, Patrick; Ometto, Jean; Rammig, Anja</p> <p>2016-04-01</p> <p>The existence, magnitude and duration of a supposed "CO2 fertilization" effect in tropical forests remains largely undetermined, despite being suggested for nearly 20 years as a key knowledge gap for understanding the future resilience of Amazonian forests and its impact on the global carbon cycle. Reducing this uncertainty is critical for assessing the future of the Amazon region as well as its vulnerability to climate change. The AmazonFACE (Free-Air CO2 Enrichment) research program is an integrated model-experiment initiative of unprecedented scope in an old-growth Amazon forest near Manaus, Brazil - the first of its kind in tropical forest. The experimental treatment will simulate an atmospheric CO2 concentration [CO2] of the future in order to address the question: "How will rising atmospheric CO2 affect the resilience of the Amazon forest, the biodiversity it harbors, and the ecosystem services it provides, in light of projected climatic changes?" AmazonFACE is divided into three phases: (I) pre-experimental ecological characterization of the research site; (II) pilot experiment comprised of two 30-m diameter plots, with one treatment plot maintained at elevated [CO2] (ambient +200 ppmv), and the other control plot at ambient [CO2]; and (III) a fully-replicated long-term experiment comprised of four pairs of control/treatment FACE plots maintained for 10 years. A team of scientists from Brazil, USA, Australia and Europe will employ state-of-the-art methods to study the forest inside these plots in terms of carbon metabolism and cycling, water use, nutrient cycling, forest community composition, and interactions with environmental stressors. All project phases also encompass ecosystem-modeling activities in a way such that models provide hypothesis to be verified in the experiment, which in turn will feed models to ultimately produce more accurate projections of the environment. Resulting datasets and analyses will be a valuable resource for a broad community, especially ecosystem and climate modelers, and policy-makers.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PhDT.......153T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PhDT.......153T"><span>Remote sensing of forest dynamics and land use in Amazonia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Toomey, Michael Paul</p> <p></p> <p>The rich, vast Amazonian ecosystem is directly and indirectly threatened by human activities; remote sensing serves as an essential tool for monitoring, understanding and mitigating these threats. A multi-faceted body of work is described here, addressing three major issues that employ and advance remote sensing techniques for the study of Amazonia and other tropical rainforest regions. In Chapter 2, canopy reflectance modeling and satellite observations were used to quantify the effect of epiphylls on remote sensing of humid forests. Modeling simulations demonstrated sensitivity of canopy-level near infrared and green reflectance to epiphylls on leaves. Time series of Moderate Resolution Imaging Spectrometer (MODIS) data corroborated the modeling results, suggesting a degree of coupling between epiphyll cover and vegetation indices which must be accounted for when using optical remote sensing in humid forests. In Chapter 4, 11 years (2000--2010) of MODIS land surface temperature (LST) data covering the entire Amazon basin were used to ascertain the role of heat stress during droughts in 2005 and 2010. Preliminary accuracy assessments showed that LST data provided reasonably accurate estimates of daytime air temperatures (RMSE = 1.45°C; Chapter 3). There were moderate to strong correlations between LST-based air temperature estimates and tower measurements (mean r = 0.64), illustrating a sensitivity to temporal variability. During both droughts, MODIS LST data detected anomalously high daytime and nighttime canopy temperatures throughout drought-affected regions. Multivariate linear models of LST and precipitation anomalies explained 65.1% of the variability in forest biomass losses, as determined from a wide network of forest inventory plots. These results suggest that models should incorporate both heat and moisture to predict drought effects on tropical forests. In Chapter 5, I performed high spatial and temporal resolution modeling of carbon stocks and fluxes in the state of Rondonia, Brazil for the period 1985--2009. Based on this analysis, Rondonia contributed ˜4% of pan-tropical humid forest deforestation emissions while carbon uptake by secondary forest was negligible due to limited spatial extent and high turnover rates. Spatial analysis of land cover change demonstrated the necessity for fine resolution carbon monitoring in tropical regions dominated by non-mechanized, smallholder land uses.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19967179','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19967179"><span>Primate community of the tropical rain forests of Saracá-Taqüera National Forest, Pará, Brazil.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Oliveira, L C; Loretto, D; Viana, L R; Silva, J S; Fernandes, W G</p> <p>2009-11-01</p> <p>Brazil is the richest country in the world in terms of primate species and the Amazonian rain forest is one of the richest biomes containing 15 (ca. 90%) of the Neotropical primate genera. Although considered key elements in conservation strategies, there is only anecdotal information on primates for several protected areas within the region. Here we present new data on the community composition of the primates in the Saracá-Taqüera National Forest (429,600 ha), an actively mined, bauxite rich area, in Pará, Brazil. We used information from the literature, technical reports, museum data, and interviews conducted with agents from the Brazilian Institute of the Environment and Natural Renewable Resources (Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis - IBAMA) and members of the local 'Quilombo' community. In addition, from July 2003 to June 2007, we carried out 19 field trips ranging from 10 to15 days each, amounting to a total effort of 1,230 hours and 1,420 km of censuses, resulting in 1,034 records of eight primate species (Saguinus martinsi, Saguinus midas, Saimiri sciureus, Cebus apella, Pithecia pithecia, Chiropotes sagulatus, Ateles paniscus, and Alouatta macconelli). Two other species (Cebus olivaceus and Aotus trivirgatus) were recorded only indirectly, through interviews and literature data. In all, Alouatta macconelli was the most frequently recorded species (43% of all records); while Saguinus midas and P. pithecia were the least (ca. 0.4 and 0.6% of all records). Based on our results, we discuss group sizes as well as taxonomic problems concerning the genera Pithecia and Chiropotes, for which we registered individuals displaying phenotypic geographical variation and two different forms, respectively. Despite the deforestation inherent in bauxite mining, the Saracá-Taqüera National Forest still has a remarkable richness of primate species. Our study results place this National Forest amongst the richest reserves, in terms of primate species, in the Amazon region.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010046974','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010046974"><span>An Integrated Use of Experimental, Modeling and Remote Sensing Techniques to Investigate Carbon and Phosphorus Dynamics in the Humid Tropics</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Townsend, Alan R.; Asner, Gregory P.; Bustamante, Mercedes M. C.</p> <p>2001-01-01</p> <p>Moist tropical forests comprise one of the world's largest and most diverse biomes, and exchange more carbon, water, and energy with the atmosphere than any other ecosystem. In recent decades, tropical forests have also become one of the globe's most threatened biomes, subjected to exceptionally high rates of deforestation and land degradation. Thus, the importance of and threats to tropical forests are undeniable, yet our understanding of basic ecosystem processes in both intact and disturbed portions of the moist tropics remains poorer than for almost any other major biome. Our approach in this project was to take a multi-scale, multi-tool approach to address two different problems. First, we wanted to test if land-use driven changes in the cycles of probable limiting nutrients in forest systems were a key driver in the frequently observed pattern of declining pasture productivity and carbon stocks. Given the enormous complexity of land use change in the tropics, in which one finds a myriad of different land use types and intensities overlain on varying climates and soil types, we also wanted to see if new remote sensing techniques would allow some novel links between parameters which could be sensed remotely, and key biogeochemical variables which cannot. Second, we addressed to general questions about the role of tropical forests in the global carbon cycle. First, we used a new approach for quantifying and minimizing non-biological artifacts in the NOAA/NASA AVHRR Pathfinder time series of surface reflectance data so that we could address potential links between Amazonian forest dynamics and ENSO cycles. Second, we showed that the disequilibrium in C-13 exchanged between land and atmosphere following tropical deforestation probably has a significant impact on the use of 13-CO2 data to predict regional fluxes in the global carbon cycle.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4242196','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4242196"><span>The Function of the Superficial Root Mat in the Biogeochemical Cycles of Nutrients in Congolese Eucalyptus Plantations</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>LACLAU, JEAN‐PAUL; TOUTAIN, FRANÇOIS; M’BOU, ARMEL THONGO; ARNAUD, MICHEL; JOFFRE, RICHARD; RANGER, JACQUES</p> <p>2004-01-01</p> <p>• Background and Aims The importance of superficial root mats inside the forest floor for the nutrition of Amazonian rain forests has been extensively investigated. The present study was aimed at assessing the function of a root mat adherent to decomposing organic material observed in Eucalyptus plantations. • Methods The development of the root mat was studied through micromorphological observations of thin litter sections, and the influence of soil microtopography and soil water repellency on root mat biomass was assessed in situ on an area of 5 m2. In addition, input–output budgets of nutrients within the forest floor were established from measurements of litterfall, dissolved nutrients in gravitational solutions, and forest floor nutrient contents. • Key Findings The amounts of nutrients released during litter decay in this ecosystem during the period of study were, on average, 46, 3, 4, 19 and 17 kg ha–1 year–1 for N, P, K, Ca and Mg, respectively. The simultaneous measurements of the chemical composition of throughfall solutions and leachates beneath the forest floor showed a very quick uptake of nutrients by the root mat during the decomposition processes. Indeed, the solutions did not become noticeably enriched in nutrients during their passage through the holorganic layer, despite large amounts of elements being released during litter decay. The root mat biomass decreased significantly during the dry season, and a preferential development in microdepressions at the soil surface was observed. A strong water repellency observed in these depressions might enhance the ability of the roots to take up water and nutrients during the dry periods. • Conclusions The root mat was active throughout the year to catch the flux of nutrients from the biodegradation of the forest floor, preventing the transfer of dissolved nutrients toward deeper soil horizons. This mechanism is involved in the successful adaptation of this Eucalyptus hybrid in areas covered by ‘climacic’ savannas in Congo. PMID:14749252</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70135621','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70135621"><span>Widespread loess-like deposit in the Martian northern lowlands identifies Middle Amazonian climate change</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Skinner, James A.; Tanaka, Kenneth L.; Platz, Thomas</p> <p>2014-01-01</p> <p>Consistently mappable units critical to distinguishing the style and interplay of geologic processes through time are sparse in the Martian lowlands. This study identifies a previously unmapped Middle Amazonian (ca. 1 Ga) unit (Middle Amazonian lowland unit, mAl) that postdates the Late Hesperian and Early Amazonian lowland plains by >2 b.y. The unit is regionally defined by subtle marginal scarps and slopes, has a mean thickness of 32 m, and extends >3.1 × 106 km2 between lat 35°N and 80°N. Pedestal-type craterforms and nested, arcuate ridges (thumbprint terrain) tend to occur adjacent to unit mAl outcrops, suggesting that current outcrops are vestiges of a more extensive deposit that previously covered ∼16 × 106 km2. Exposed layers, surface pits, and the draping of subjacent landforms allude to a sedimentary origin, perhaps as a loess-like deposit emplaced rhythmically through atmospheric fallout. We propose that unit mAl accumulated coevally with, and at the expense of, the erosion of the north polar basal units, identifying a major episode of Middle Amazonian climate-driven sedimentation in the lowlands. This work links ancient sedimentary processes to climate change that occurred well before those implied by current orbital and spin axis models.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27230632','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27230632"><span>Heterogeneous effects of market integration on sub-adult body size and nutritional status among the Shuar of Amazonian Ecuador.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Urlacher, Samuel S; Liebert, Melissa A; Josh Snodgrass, J; Blackwell, Aaron D; Cepon-Robins, Tara J; Gildner, Theresa E; Madimenos, Felicia C; Amir, Dorsa; Bribiescas, Richard G; Sugiyama, Lawrence S</p> <p>2016-07-01</p> <p>Market integration (MI)-increasing production for and consumption from a market-based economy-is drastically altering traditional ways of life and environmental conditions among indigenous Amazonian peoples. The effects of MI on the biology and health of Amazonian children and adolescents, however, remain unclear. This study examines the impact of MI on sub-adult body size and nutritional status at the population, regional and household levels among the Shuar of Amazonian Ecuador. Anthropometric data were collected between 2005-2014 from 2164 Shuar (aged 2-19 years) living in two geographic regions differing in general degree of MI. High-resolution household economic, lifestyle and dietary data were collected from a sub-sample of 631 participants. Analyses were performed to investigate relationships between body size and year of data collection, region and specific aspects of household MI. Results from temporal and regional analyses suggest that MI has a significant and overall positive impact on Shuar body size and nutritional status. However, household-level results exhibit nuanced and heterogeneous specific effects of MI underlying these overarching relationships. This study provides novel insight into the complex socio-ecological pathways linking MI, physical growth and health among the Shuar and other indigenous Amazonian populations.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4992548','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4992548"><span>Heterogeneous effects of market integration on subadult body size and nutritional status among the Shuar of Amazonian Ecuador</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Urlacher, Samuel S.; Liebert, Melissa A.; Snodgrass, J. Josh; Blackwell, Aaron D.; Cepon-Robins, Tara J.; Gildner, Theresa E.; Madimenos, Felicia C.; Amir, Dorsa; Bribiescas, Richard G.; Sugiyama, Lawrence S.</p> <p>2016-01-01</p> <p>Background Market integration (MI) – increasing production for and consumption from a market-based economy – is drastically altering traditional ways of life and environmental conditions among indigenous Amazonian peoples. The effects of MI on the biology and health of Amazonian children and adolescents, however, remain unclear. Aim This study examines the impact of MI on subadult body size and nutritional status at the population, regional, and household levels among the Shuar of Amazonian Ecuador. Subjects and Methods Anthropometric data were collected between 2005 and 2014 from 2,164 Shuar (age 2-19 years) living in two geographic regions differing in general degree of MI. High-resolution household economic, lifestyle, and dietary data were collected from a subsample of 631 participants. Analyses were performed to investigate relationships between body size and year of data collection, region, and specific aspects of household MI. Results Results from temporal and regional analyses suggest that MI has a significant and overall positive impact on Shuar body size and nutritional status. However, household-level results exhibit nuanced and heterogeneous specific effects of MI underlying these overarching relationships. Conclusion This study provides novel insight into the complex socio-ecological pathways linking MI, physical growth, and health among the Shuar and other indigenous Amazonian populations. PMID:27230632</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.A11C0127B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.A11C0127B"><span>Following Saharan Dust Outbreak Toward The Amazon Basin</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ben Ami, Y.; Koren, I.; Rudich, Y.; Flores, M.</p> <p>2008-12-01</p> <p>The role of the Amazon rainforest on earth climatic system is well recognized. To keep forest wellbeing and the fragile balance between the rainforest and the atmosphere, the Amazon must contain a satisfactory amount of nutrients to support the plants. The extensive rain and floods wash most of the soluble nutrients from the rainforest soil, leaving behind acidic kaolinite clay or sandy soil, with limited minerals for plant growth. It was suggested that lack of mineral in the soil may be replenished by deposition of Saharan mineral dust. Using remote sensing data (from the A-train satellites constellation) following with in-situ measurements (as part of the AMazonian Aerosol CharacteriZation Experiment (AMZE) campaign), ground-based data (from AErosol RObotic NETwork (AERONET)) and back trajectory calculations, we analyzed Saharan dust transport toward the Amazon basin during the AMZE period (Feb 7 to Mar 14, 2008). Dust mass, sink, vertical distribution and surface wind speeds were analyzed over the Bodele depression (located in Chad), where most of the dust is emitted, along the Atlantic Ocean and near the Brazilian coastline. Using an integrated data analysis approach we followed dust packages from their emission in the Sahara to their sink in the Amazon forest.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15592409','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15592409"><span>Wet periods in northeastern Brazil over the past 210 kyr linked to distant climate anomalies.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Xianfeng; Auler, Augusto S; Edwards, R Lawrence; Cheng, Hai; Cristalli, Patricia S; Smart, Peter L; Richards, David A; Shen, Chuan-Chou</p> <p>2004-12-09</p> <p>The tropics are the main source of the atmosphere's sensible and latent heat, and water vapour, and are therefore important for reconstructions of past climate. But long, accurately dated records of southern tropical palaeoclimate, which would allow the establishment of climatic connections to distant regions, have not been available. Here we present a 210,000-year (210-kyr) record of wet periods in tropical northeastern Brazil--a region that is currently semi-arid. The record is obtained from speleothems and travertine deposits that are accurately dated using the U/Th method. We find wet periods that are synchronous with periods of weak East Asian summer monsoons, cold periods in Greenland, Heinrich events in the North Atlantic and periods of decreased river runoff to the Cariaco basin. We infer that the wet periods may be explained with a southward displacement of the Intertropical Convergence Zone. This widespread synchroneity of climate anomalies suggests a relatively rapid global reorganization of the ocean-atmosphere system. We conclude that the wet periods probably affected rainforest distribution, as plant fossils show that forest expansion occurred during these intermittent wet intervals, and opened a forest corridor between the Amazonian and Atlantic rainforests.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1599783','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1599783"><span>Strikingly variable divergence times inferred across an Amazonian butterfly ‘suture zone’</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Whinnett, Alaine; Zimmermann, Marie; Willmott, Keith R; Herrera, Nimiadina; Mallarino, Ricardo; Simpson, Fraser; Joron, Mathieu; Lamas, Gerardo; Mallet, James</p> <p>2005-01-01</p> <p>‘Suture zones’ are areas where hybrid and contact zones of multiple taxa are clustered. Such zones have been regarded as strong evidence for allopatric divergence by proponents of the Pleistocene forest refugia theory, a vicariance hypothesis frequently used to explain diversification in the Amazon basin. A central prediction of the refugia and other vicariance theories is that the taxa should have a common history so that divergence times should be coincident among taxa. A suture zone for Ithomiinae butterflies near Tarapoto, NE Peru, was therefore studied to examine divergence times of taxa in contact across the zone. We sequenced 1619 bp of the mitochondrial COI/COII region in 172 individuals of 31 species from across the suture zone. Inferred divergence times differed remarkably, with divergence between some pairs of widespread species (each of which may have two or more subspecies interacting in the zone, as in the genus Melinaea) being considerably less than that between hybridizing subspecies in other genera (for instance in Oleria). Our data therefore strongly refute a simple hypothesis of simultaneous vicariance and suggest that ongoing parapatric or other modes of differentiation in continuous forest may be important in driving diversification in Amazonia. PMID:16271979</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23760636','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23760636"><span>Forest productivity and water stress in Amazonia: observations from GOSAT chlorophyll fluorescence.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lee, Jung-Eun; Frankenberg, Christian; van der Tol, Christiaan; Berry, Joseph A; Guanter, Luis; Boyce, C Kevin; Fisher, Joshua B; Morrow, Eric; Worden, John R; Asefi, Salvi; Badgley, Grayson; Saatchi, Sassan</p> <p>2013-06-22</p> <p>It is unclear to what extent seasonal water stress impacts on plant productivity over Amazonia. Using new Greenhouse gases Observing SATellite (GOSAT) satellite measurements of sun-induced chlorophyll fluorescence, we show that midday fluorescence varies with water availability, both of which decrease in the dry season over Amazonian regions with substantial dry season length, suggesting a parallel decrease in gross primary production (GPP). Using additional SeaWinds Scatterometer onboard QuikSCAT satellite measurements of canopy water content, we found a concomitant decrease in daily storage of canopy water content within branches and leaves during the dry season, supporting our conclusion. A large part (r(2) = 0.75) of the variance in observed monthly midday fluorescence from GOSAT is explained by water stress over moderately stressed evergreen forests over Amazonia, which is reproduced by model simulations that include a full physiological representation of photosynthesis and fluorescence. The strong relationship between GOSAT and model fluorescence (r(2) = 0.79) was obtained using a fixed leaf area index, indicating that GPP changes are more related to environmental conditions than chlorophyll contents. When the dry season extended to drought in 2010 over Amazonia, midday basin-wide GPP was reduced by 15 per cent compared with 2009.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27974517','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27974517"><span>Evolutionary heritage influences Amazon tree ecology.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Coelho de Souza, Fernanda; Dexter, Kyle G; Phillips, Oliver L; Brienen, Roel J W; Chave, Jerome; Galbraith, David R; Lopez Gonzalez, Gabriela; Monteagudo Mendoza, Abel; Pennington, R Toby; Poorter, Lourens; Alexiades, Miguel; Álvarez-Dávila, Esteban; Andrade, Ana; Aragão, Luis E O C; Araujo-Murakami, Alejandro; Arets, Eric J M M; Aymard C, Gerardo A; Baraloto, Christopher; Barroso, Jorcely G; Bonal, Damien; Boot, Rene G A; Camargo, José L C; Comiskey, James A; Valverde, Fernando Cornejo; de Camargo, Plínio B; Di Fiore, Anthony; Elias, Fernando; Erwin, Terry L; Feldpausch, Ted R; Ferreira, Leandro; Fyllas, Nikolaos M; Gloor, Emanuel; Herault, Bruno; Herrera, Rafael; Higuchi, Niro; Honorio Coronado, Eurídice N; Killeen, Timothy J; Laurance, William F; Laurance, Susan; Lloyd, Jon; Lovejoy, Thomas E; Malhi, Yadvinder; Maracahipes, Leandro; Marimon, Beatriz S; Marimon-Junior, Ben H; Mendoza, Casimiro; Morandi, Paulo; Neill, David A; Vargas, Percy Núñez; Oliveira, Edmar A; Lenza, Eddie; Palacios, Walter A; Peñuela-Mora, Maria C; Pipoly, John J; Pitman, Nigel C A; Prieto, Adriana; Quesada, Carlos A; Ramirez-Angulo, Hirma; Rudas, Agustin; Ruokolainen, Kalle; Salomão, Rafael P; Silveira, Marcos; Stropp, Juliana; Ter Steege, Hans; Thomas-Caesar, Raquel; van der Hout, Peter; van der Heijden, Geertje M F; van der Meer, Peter J; Vasquez, Rodolfo V; Vieira, Simone A; Vilanova, Emilio; Vos, Vincent A; Wang, Ophelia; Young, Kenneth R; Zagt, Roderick J; Baker, Timothy R</p> <p>2016-12-14</p> <p>Lineages tend to retain ecological characteristics of their ancestors through time. However, for some traits, selection during evolutionary history may have also played a role in determining trait values. To address the relative importance of these processes requires large-scale quantification of traits and evolutionary relationships among species. The Amazonian tree flora comprises a high diversity of angiosperm lineages and species with widely differing life-history characteristics, providing an excellent system to investigate the combined influences of evolutionary heritage and selection in determining trait variation. We used trait data related to the major axes of life-history variation among tropical trees (e.g. growth and mortality rates) from 577 inventory plots in closed-canopy forest, mapped onto a phylogenetic hypothesis spanning more than 300 genera including all major angiosperm clades to test for evolutionary constraints on traits. We found significant phylogenetic signal (PS) for all traits, consistent with evolutionarily related genera having more similar characteristics than expected by chance. Although there is also evidence for repeated evolution of pioneer and shade tolerant life-history strategies within independent lineages, the existence of significant PS allows clearer predictions of the links between evolutionary diversity, ecosystem function and the response of tropical forests to global change. © 2016 The Authors.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5204144','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5204144"><span>Evolutionary heritage influences Amazon tree ecology</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Coelho de Souza, Fernanda; Dexter, Kyle G.; Phillips, Oliver L.; Brienen, Roel J. W.; Chave, Jerome; Galbraith, David R.; Lopez Gonzalez, Gabriela; Monteagudo Mendoza, Abel; Pennington, R. Toby; Poorter, Lourens; Alexiades, Miguel; Álvarez-Dávila, Esteban; Andrade, Ana; Aragão, Luis E. O. C.; Araujo-Murakami, Alejandro; Arets, Eric J. M. M.; Aymard C, Gerardo A.; Baraloto, Christopher; Barroso, Jorcely G.; Bonal, Damien; Boot, Rene G. A.; Camargo, José L. C.; Comiskey, James A.; Valverde, Fernando Cornejo; de Camargo, Plínio B.; Di Fiore, Anthony; Erwin, Terry L.; Feldpausch, Ted R.; Ferreira, Leandro; Fyllas, Nikolaos M.; Gloor, Emanuel; Herault, Bruno; Herrera, Rafael; Higuchi, Niro; Honorio Coronado, Eurídice N.; Killeen, Timothy J.; Laurance, William F.; Laurance, Susan; Lloyd, Jon; Lovejoy, Thomas E.; Malhi, Yadvinder; Maracahipes, Leandro; Marimon, Beatriz S.; Marimon-Junior, Ben H.; Mendoza, Casimiro; Morandi, Paulo; Neill, David A.; Vargas, Percy Núñez; Oliveira, Edmar A.; Lenza, Eddie; Palacios, Walter A.; Peñuela-Mora, Maria C.; Pipoly, John J.; Pitman, Nigel C. A.; Prieto, Adriana; Quesada, Carlos A.; Ramirez-Angulo, Hirma; Rudas, Agustin; Ruokolainen, Kalle; Salomão, Rafael P.; Silveira, Marcos; ter Steege, Hans; Thomas-Caesar, Raquel; van der Hout, Peter; van der Heijden, Geertje M. F.; van der Meer, Peter J.; Vasquez, Rodolfo V.; Vieira, Simone A.; Vilanova, Emilio; Vos, Vincent A.; Wang, Ophelia; Young, Kenneth R.; Zagt, Roderick J.; Baker, Timothy R.</p> <p>2016-01-01</p> <p>Lineages tend to retain ecological characteristics of their ancestors through time. However, for some traits, selection during evolutionary history may have also played a role in determining trait values. To address the relative importance of these processes requires large-scale quantification of traits and evolutionary relationships among species. The Amazonian tree flora comprises a high diversity of angiosperm lineages and species with widely differing life-history characteristics, providing an excellent system to investigate the combined influences of evolutionary heritage and selection in determining trait variation. We used trait data related to the major axes of life-history variation among tropical trees (e.g. growth and mortality rates) from 577 inventory plots in closed-canopy forest, mapped onto a phylogenetic hypothesis spanning more than 300 genera including all major angiosperm clades to test for evolutionary constraints on traits. We found significant phylogenetic signal (PS) for all traits, consistent with evolutionarily related genera having more similar characteristics than expected by chance. Although there is also evidence for repeated evolution of pioneer and shade tolerant life-history strategies within independent lineages, the existence of significant PS allows clearer predictions of the links between evolutionary diversity, ecosystem function and the response of tropical forests to global change. PMID:27974517</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110023554','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110023554"><span>The Impact of Rise of the Andes and Amazon Landscape Evolution on Diversification of Lowland terra-firme Forest Birds</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Aleixo, Alexandre; Wilkinson, M. Justin</p> <p>2011-01-01</p> <p>Since the 19th Century, the unmatched biological diversity of Amazonia has stimulated a diverse set of hypotheses accounting for patterns of species diversity and distribution in mega-diverse tropical environments. Unfortunately, the evidence supporting particular hypotheses to date is at best described as ambiguous, and no generalizations have emerged yet, mostly due to the lack of comprehensive comparative phylogeographic studies with thorough trans-Amazonian sampling of lineages. Here we report on spatial and temporal patterns of diversification estimated from mitochondrial gene trees for 31 lineages of birds associated with upland terra-firme forest, the dominant habitat in modern lowland Amazonia. The results confirm the pervasive role of Amazonian rivers as primary barriers separating sister lineages of birds, and a protracted spatio-temporal pattern of diversification, with a gradual reduction of earlier (1st and 2nd) and older (> 2 mya) splits associated with each lineage in an eastward direction. (The easternmost tributaries of the Amazon, the Xingu and Tocantins Rivers, are not associated with any splits older than > 2 mya). For the suboscine passerines, maximum-likelihood estimates of rates of diversification point to an overall constant rate over the past 5 my (up to a significant downturn at 300,000 y ago). This "younging-eastward" pattern may have an abiotic explanation related to landscape evolution. Triggered by a new pulse of Andean uplift, it has been proposed that modern Amazon basin landscapes may have evolved successively eastward, away from the mountain chain, starting approximately 10 mya. This process was likely based on the deposition of vast fluvial sediment masses, known as megafans, that may have extended progressively and in series eastward from Andean sources. This process plausibly explains the progressive extinction of original Pebas wetland of western-central Amazonia by the present fluvial landsurfaces of a more terra-firme type. The youngest landsurfaces thus lie furthest from the mountains. In this scenario major drainages were also reoriented in wholesale fashion away from a northerly orientation generally towards the east and an Atlantic Ocean outlet. The advance of megafans is best seen by the location of axial rivers such as the Orinoco and Mamore which lie against the cratonic margins furthest from the Andes, at the distal ends of major megafan ramparts. More importantly, other major river courses in western-central Amazonia will have been established at progressively younger dates with distance eastward. If this landscape-sequence scenario is accurate, it parallels the progressive younging of the passerine lineages. The bird DNA data appears to confirm strongly the pervasive role of Amazonian rivers--as primary barriers separating sister lineages of birds, and thus probably as facilitaters of bird speciation. We show for the first time that a general spatio-temporal pattern of diversification for terra-firme lineages in the Amazon is associated with rivers ("younging-eastward"), and furthermore parallels a specific scenario of regional drainage evolution.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26223450','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26223450"><span>Implications for changes in Anopheles darlingi biting behaviour in three communities in the peri-Iquitos region of Amazonian Peru.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Moreno, Marta; Saavedra, Marlon P; Bickersmith, Sara A; Lainhart, William; Tong, Carlos; Alava, Freddy; Vinetz, Joseph M; Conn, Jan E</p> <p>2015-07-30</p> <p>Malaria transmission in the peri-Iquitos region of Amazonian Peru has been designated as seasonal and hypo-endemic with recently described hyper-endemic hotspots. Despite relatively recent distribution of long-lasting insecticidal bed nets (LLINs), malaria in Amazonian Peru persists and increased substantially in 2014 compared to previous years. Anopheles darlingi, identified as the main malaria vector, is known for its variable behaviour depending on locality and environment. To evaluate vector biology metrics in relation to seasonality and malaria transmission, mosquito collections were carried out in three localities in the peri-Iquitos region, Loreto, Peru in 2011-2012. Human landing catch (HLC) collection method, Shannon (SHA) and CDC trap types were compared for effectiveness in a neotropical setting. Abundance, human biting rate and entomological inoculation rate (EIR) were measured to provide an updated view of transmission patterns post-LLIN distribution. HLC collected significantly more anopheline mosquitoes than SHA and CDC light traps. Anopheles darlingi was the most prevalent species in all three villages (84% overall). Biting patterns varied depending on trap type, season and village. EIR varied temporally (monthly) and spatially and the highest (2.52) occurred during the 2012 malaria outbreak in Cahuide. Unexpectedly there was a high infection rate (1.47 and 1.75) outside the normal malaria transmission season, coincident with a second local outbreak in Cahuide. The first identification of Anopheles dunhami and Anopheles oswaldoi C in Peru, using molecular markers, is also reported in this study. These data underscore the importance of HLC as the most meaningful collection method for measuring vector biology indices in this region. The highest monthly EIR provides additional evidence of seasonal transmission in riverine localities correlated with high river levels, and An. darlingi as the only contributor to transmission. The trend of an increase in outdoor-biting together with early-evening infected mosquitoes may undermine the effectiveness of LLINs as a primary malaria intervention.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160000383','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160000383"><span>Advances in Remote Sensing for Vegetation Dynamics and Agricultural Management</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tucker, Compton; Puma, Michael</p> <p>2015-01-01</p> <p>Spaceborne remote sensing has led to great advances in the global monitoring of vegetation. For example, the NASA Global Inventory Modeling and Mapping Studies (GIMMS) group has developed widely used datasets from the Advanced Very High Resolution Radiometer (AVHRR) sensors as well as the Moderate Resolution Imaging Spectroradiometer (MODIS) map imagery and normalized difference vegetation index datasets. These data are valuable for analyzing vegetation trends and variability at the regional and global levels. Numerous studies have investigated such trends and variability for both natural vegetation (e.g., re-greening of the Sahel, shifts in the Eurasian boreal forest, Amazonian drought sensitivity) and crops (e.g., impacts of extremes on agricultural production). Here, a critical overview is presented on recent developments and opportunities in the use of remote sensing for monitoring vegetation and crop dynamics.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11413639','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11413639"><span>The importance of leaf- and litter-feeding invertebrates as sources of animal protein for the Amazonian Amerindians.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Paoletti, M G; Dufour, D L; Cerda, H; Torres, F; Pizzoferrato, L; Pimentel, D</p> <p>2000-11-22</p> <p>At least 32 Amerindian groups in the Amazon basin use terrestrial invertebrates as food. Leaf- and litter-consuming invertebrates provide the more important, underestimated food sources for many Amerindian groups. Further, litter-consuming earthworms are also an important food resource for the Ye'Kuana (also known as Makiritare) in the Alto Orinoco (Amazonas, Venezuela). By selecting these small invertebrates the Amerindians are choosing their animal food from those food webs in the rainforest which have the highest energy flow and which constitute the greatest renewable stock of readily available nutrients. Here we show that the consumption of leaf- and litter-feeding invertebrates as a means of recovering protein, fat and vitamins by the forest-living peoples offers a new perspective for the development of sustainable animal food production within the paradigm of biodiversity maintenance.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26175605','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26175605"><span>Records of Coendouichillus (Rodentia, Erethizontidae) from the Lower Urubamba Region of Peru.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gregory, Tremaine; Lunde, Darrin; Zamora-Meza, Hugo Tomás; Carrasco-Rueda, Farah</p> <p>2015-01-01</p> <p>Coendouichillus was first described in 2001 by Voss and da Silva, with a range from Amazonian Ecuador to Iquitos, Peru. Here, we describe an adult female Coendouichillus specimen collected in a Tomahawk trap in the forest canopy of the Lower Urubamba Region of Peru in October 2013. We also describe pathologies and behaviors observed through 379 camera trapping photo events (2,196 photos) gathered in natural canopy bridges over the course of a year (7,198 trap nights), including information on activity period over the course of the day and over the course of the lunar cycle. We conservatively estimate that 17 individuals were photographed, including one juvenile. Being 900 km away from Iquitos, Peru (the site of the closest record), discovery of this species in the Lower Urubamba constitutes a significant range extension.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870044922&hterms=acid+rain&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dacid%2Brain','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870044922&hterms=acid+rain&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dacid%2Brain"><span>Trace gas exchanges and transports over the Amazonian rain forest</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Garstang, Michael; Greco, Steve; Scala, John; Harriss, Robert; Browell, Edward; Sachse, Glenn; Simpson, Joanne; Tao, Wei-Kuo; Torres, Arnold</p> <p>1986-01-01</p> <p>Early results are presented from a program to model deep convective transport of chemical species by means of in situ data collection and numerical models. Data were acquired during the NASA GTE Amazon Boundary Layer Experiment in July-August 1985. Airborne instrumentation, including a UV-DIAL system, collected data on the O3, CO, NO, temperature and water vapor profiles from the surface to 400 mb altitude, while GOES imagery tracked convective clouds over the study area. A two-dimensional cloud model with small amplitude random temperature fluctuations at low levels, which simulated thermals, was used to describe the movements of the chemical species sensed in the convective atmosphere. The data was useful for evaluating the accuracy of the cloud model, which in turn was effective in describing the circulation of the chemical species.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70040062','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70040062"><span>Book review: Conservation biology of Hawaiian forest birds: Implications for island avifauna</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Engstrom, R. Todd; van Riper, Charles</p> <p>2010-01-01</p> <p>Review info: Conservation Biology of Hawaiian Forest Birds: Implications for Island Avifauna. By Thane K. Pratt, Carter T. Atkinson, Paul C. Banko, James D. Jacobi, and Bethany L. Woodworth, Eds., 2009. ISBN 978-0300141085, 707 pp.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20385814','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20385814"><span>Pre-Columbian agricultural landscapes, ecosystem engineers, and self-organized patchiness in Amazonia.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>McKey, Doyle; Rostain, Stéphen; Iriarte, José; Glaser, Bruno; Birk, Jago Jonathan; Holst, Irene; Renard, Delphine</p> <p>2010-04-27</p> <p>The scale and nature of pre-Columbian human impacts in Amazonia are currently hotly debated. Whereas pre-Columbian people dramatically changed the distribution and abundance of species and habitats in some parts of Amazonia, their impact in other parts is less clear. Pioneer research asked whether their effects reached even further, changing how ecosystems function, but few in-depth studies have examined mechanisms underpinning the resilience of these modifications. Combining archeology, archeobotany, paleoecology, soil science, ecology, and aerial imagery, we show that pre-Columbian farmers of the Guianas coast constructed large raised-field complexes, growing on them crops including maize, manioc, and squash. Farmers created physical and biogeochemical heterogeneity in flat, marshy environments by constructing raised fields. When these fields were later abandoned, the mosaic of well-drained islands in the flooded matrix set in motion self-organizing processes driven by ecosystem engineers (ants, termites, earthworms, and woody plants) that occur preferentially on abandoned raised fields. Today, feedbacks generated by these ecosystem engineers maintain the human-initiated concentration of resources in these structures. Engineer organisms transport materials to abandoned raised fields and modify the structure and composition of their soils, reducing erodibility. The profound alteration of ecosystem functioning in these landscapes coconstructed by humans and nature has important implications for understanding Amazonian history and biodiversity. Furthermore, these landscapes show how sustainability of food-production systems can be enhanced by engineering into them follows that maintain ecosystem services and biodiversity. Like anthropogenic dark earths in forested Amazonia, these self-organizing ecosystems illustrate the ecological complexity of the legacy of pre-Columbian land use.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2867901','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2867901"><span>Pre-Columbian agricultural landscapes, ecosystem engineers, and self-organized patchiness in Amazonia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>McKey, Doyle; Rostain, Stéphen; Iriarte, José; Glaser, Bruno; Birk, Jago Jonathan; Holst, Irene; Renard, Delphine</p> <p>2010-01-01</p> <p>The scale and nature of pre-Columbian human impacts in Amazonia are currently hotly debated. Whereas pre-Columbian people dramatically changed the distribution and abundance of species and habitats in some parts of Amazonia, their impact in other parts is less clear. Pioneer research asked whether their effects reached even further, changing how ecosystems function, but few in-depth studies have examined mechanisms underpinning the resilience of these modifications. Combining archeology, archeobotany, paleoecology, soil science, ecology, and aerial imagery, we show that pre-Columbian farmers of the Guianas coast constructed large raised-field complexes, growing on them crops including maize, manioc, and squash. Farmers created physical and biogeochemical heterogeneity in flat, marshy environments by constructing raised fields. When these fields were later abandoned, the mosaic of well-drained islands in the flooded matrix set in motion self-organizing processes driven by ecosystem engineers (ants, termites, earthworms, and woody plants) that occur preferentially on abandoned raised fields. Today, feedbacks generated by these ecosystem engineers maintain the human-initiated concentration of resources in these structures. Engineer organisms transport materials to abandoned raised fields and modify the structure and composition of their soils, reducing erodibility. The profound alteration of ecosystem functioning in these landscapes coconstructed by humans and nature has important implications for understanding Amazonian history and biodiversity. Furthermore, these landscapes show how sustainability of food-production systems can be enhanced by engineering into them fallows that maintain ecosystem services and biodiversity. Like anthropogenic dark earths in forested Amazonia, these self-organizing ecosystems illustrate the ecological complexity of the legacy of pre-Columbian land use. PMID:20385814</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/47118','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/47118"><span>Globalization and its implications for forest health</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Andrew Liebhold; Michael Wingfield</p> <p>2014-01-01</p> <p>Consideration of forest health is central to the sustainable management of forests. While many definitions of forest health have been proposed, the most widely adopted concept refers to the sustained functioning of desired forest ecosystem processes (Kolb et al., 1994). Legitimate complaints have been raised about the human-centric usage of the term "Forest Health...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/26495','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/26495"><span>Forest structure and development: implications for forest management</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Kevin L. O' Hara</p> <p>2004-01-01</p> <p>A general premise of forest managers is that modern silviculture should be based, in large part, on natural disturbance patterns and species' adaptations to these disturbances. An understanding of forest stand dynamics is therefore a prerequisite to sound forest management. This paper provides a brief overview of forest stand development, stand structures, and...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20183195','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20183195"><span>Mercury exposure in a high fish eating Bolivian Amazonian population with intense small-scale gold-mining activities.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Barbieri, Flavia Laura; Cournil, Amandine; Gardon, Jacques</p> <p>2009-08-01</p> <p>Methylmercury exposure in Amazonian communities through fish consumption has been widely documented in Brazil. There is still a lack of data in other Amazonian countries, which is why we conducted this study in the Bolivian Amazon basin. Simple random sampling was used from a small village located in the lower Beni River, where there is intense gold mining and high fish consumption. All participants were interviewed and hair samples were taken to measure total mercury concentrations. The hair mercury geometric mean in the general population was 3.02 microg/g (CI: 2.69-3.37; range: 0.42-15.65). Age and gender were not directly associated with mercury levels. Fish consumption showed a positive relation and so did occupation, especially small-scale gold mining. Hair mercury levels were lower than those found in Brazilian studies, but still higher than in non-exposed populations. It is necessary to assess mercury exposure in the Amazonian regions where data is still lacking, using a standardized indicator.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26702442','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26702442"><span>Estimating the global conservation status of more than 15,000 Amazonian tree species.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ter Steege, Hans; Pitman, Nigel C A; Killeen, Timothy J; Laurance, William F; Peres, Carlos A; Guevara, Juan Ernesto; Salomão, Rafael P; Castilho, Carolina V; Amaral, Iêda Leão; de Almeida Matos, Francisca Dionízia; de Souza Coelho, Luiz; Magnusson, William E; Phillips, Oliver L; de Andrade Lima Filho, Diogenes; de Jesus Veiga Carim, Marcelo; Irume, Mariana Victória; Martins, Maria Pires; Molino, Jean-François; Sabatier, Daniel; Wittmann, Florian; López, Dairon Cárdenas; da Silva Guimarães, José Renan; Mendoza, Abel Monteagudo; Vargas, Percy Núñez; Manzatto, Angelo Gilberto; Reis, Neidiane Farias Costa; Terborgh, John; Casula, Katia Regina; Montero, Juan Carlos; Feldpausch, Ted R; Honorio Coronado, Euridice N; Montoya, Alvaro Javier Duque; Zartman, Charles Eugene; Mostacedo, Bonifacio; Vasquez, Rodolfo; Assis, Rafael L; Medeiros, Marcelo Brilhante; Simon, Marcelo Fragomeni; Andrade, Ana; Camargo, José Luís; Laurance, Susan G W; Nascimento, Henrique Eduardo Mendonça; Marimon, Beatriz S; Marimon, Ben-Hur; Costa, Flávia; Targhetta, Natalia; Vieira, Ima Célia Guimarães; Brienen, Roel; Castellanos, Hernán; Duivenvoorden, Joost F; Mogollón, Hugo F; Piedade, Maria Teresa Fernandez; Aymard C, Gerardo A; Comiskey, James A; Damasco, Gabriel; Dávila, Nállarett; García-Villacorta, Roosevelt; Diaz, Pablo Roberto Stevenson; Vincentini, Alberto; Emilio, Thaise; Levis, Carolina; Schietti, Juliana; Souza, Priscila; Alonso, Alfonso; Dallmeier, Francisco; Ferreira, Leandro Valle; Neill, David; Araujo-Murakami, Alejandro; Arroyo, Luzmila; Carvalho, Fernanda Antunes; Souza, Fernanda Coelho; do Amaral, Dário Dantas; Gribel, Rogerio; Luize, Bruno Garcia; Pansonato, Marcelo Petrati; Venticinque, Eduardo; Fine, Paul; Toledo, Marisol; Baraloto, Chris; Cerón, Carlos; Engel, Julien; Henkel, Terry W; Jimenez, Eliana M; Maas, Paul; Mora, Maria Cristina Peñuela; Petronelli, Pascal; Revilla, Juan David Cardenas; Silveira, Marcos; Stropp, Juliana; Thomas-Caesar, Raquel; Baker, Tim R; Daly, Doug; Paredes, Marcos Ríos; da Silva, Naara Ferreira; Fuentes, Alfredo; Jørgensen, Peter Møller; Schöngart, Jochen; Silman, Miles R; Arboleda, Nicolás Castaño; Cintra, Bruno Barçante Ladvocat; Valverde, Fernando Cornejo; Di Fiore, Anthony; Phillips, Juan Fernando; van Andel, Tinde R; von Hildebrand, Patricio; Barbosa, Edelcilio Marques; de Matos Bonates, Luiz Carlos; de Castro, Deborah; de Sousa Farias, Emanuelle; Gonzales, Therany; Guillaumet, Jean-Louis; Hoffman, Bruce; Malhi, Yadvinder; de Andrade Miranda, Ires Paula; Prieto, Adriana; Rudas, Agustín; Ruschell, Ademir R; Silva, Natalino; Vela, César I A; Vos, Vincent A; Zent, Eglée L; Zent, Stanford; Cano, Angela; Nascimento, Marcelo Trindade; Oliveira, Alexandre A; Ramirez-Angulo, Hirma; Ramos, José Ferreira; Sierra, Rodrigo; Tirado, Milton; Medina, Maria Natalia Umaña; van der Heijden, Geertje; Torre, Emilio Vilanova; Vriesendorp, Corine; Wang, Ophelia; Young, Kenneth R; Baider, Claudia; Balslev, Henrik; de Castro, Natalia; Farfan-Rios, William; Ferreira, Cid; Mendoza, Casimiro; Mesones, Italo; Torres-Lezama, Armando; Giraldo, Ligia Estela Urrego; Villarroel, Daniel; Zagt, Roderick; Alexiades, Miguel N; Garcia-Cabrera, Karina; Hernandez, Lionel; Huamantupa-Chuquimaco, Isau; Milliken, William; Cuenca, Walter Palacios; Pansini, Susamar; Pauletto, Daniela; Arevalo, Freddy Ramirez; Sampaio, Adeilza Felipe; Valderrama Sandoval, Elvis H; Gamarra, Luis Valenzuela</p> <p>2015-11-01</p> <p>Estimates of extinction risk for Amazonian plant and animal species are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian tree species are likely to qualify as globally threatened under International Union for Conservation of Nature (IUCN) Red List criteria. If confirmed, these results would increase the number of threatened plant species on Earth by 22%. We show that the trends observed in Amazonia apply to trees throughout the tropics, and we predict that most of the world's >40,000 tropical tree species now qualify as globally threatened. A gap analysis suggests that existing Amazonian protected areas and indigenous territories will protect viable populations of most threatened species if these areas suffer no further degradation, highlighting the key roles that protected areas, indigenous peoples, and improved governance can play in preventing large-scale extinctions in the tropics in this century.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4681336','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4681336"><span>Estimating the global conservation status of more than 15,000 Amazonian tree species</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>ter Steege, Hans; Pitman, Nigel C. A.; Killeen, Timothy J.; Laurance, William F.; Peres, Carlos A.; Guevara, Juan Ernesto; Salomão, Rafael P.; Castilho, Carolina V.; Amaral, Iêda Leão; de Almeida Matos, Francisca Dionízia; de Souza Coelho, Luiz; Magnusson, William E.; Phillips, Oliver L.; de Andrade Lima Filho, Diogenes; de Jesus Veiga Carim, Marcelo; Irume, Mariana Victória; Martins, Maria Pires; Molino, Jean-François; Sabatier, Daniel; Wittmann, Florian; López, Dairon Cárdenas; da Silva Guimarães, José Renan; Mendoza, Abel Monteagudo; Vargas, Percy Núñez; Manzatto, Angelo Gilberto; Reis, Neidiane Farias Costa; Terborgh, John; Casula, Katia Regina; Montero, Juan Carlos; Feldpausch, Ted R.; Honorio Coronado, Euridice N.; Montoya, Alvaro Javier Duque; Zartman, Charles Eugene; Mostacedo, Bonifacio; Vasquez, Rodolfo; Assis, Rafael L.; Medeiros, Marcelo Brilhante; Simon, Marcelo Fragomeni; Andrade, Ana; Camargo, José Luís; Laurance, Susan G. W.; Nascimento, Henrique Eduardo Mendonça; Marimon, Beatriz S.; Marimon, Ben-Hur; Costa, Flávia; Targhetta, Natalia; Vieira, Ima Célia Guimarães; Brienen, Roel; Castellanos, Hernán; Duivenvoorden, Joost F.; Mogollón, Hugo F.; Piedade, Maria Teresa Fernandez; Aymard C., Gerardo A.; Comiskey, James A.; Damasco, Gabriel; Dávila, Nállarett; García-Villacorta, Roosevelt; Diaz, Pablo Roberto Stevenson; Vincentini, Alberto; Emilio, Thaise; Levis, Carolina; Schietti, Juliana; Souza, Priscila; Alonso, Alfonso; Dallmeier, Francisco; Ferreira, Leandro Valle; Neill, David; Araujo-Murakami, Alejandro; Arroyo, Luzmila; Carvalho, Fernanda Antunes; Souza, Fernanda Coelho; do Amaral, Dário Dantas; Gribel, Rogerio; Luize, Bruno Garcia; Pansonato, Marcelo Petrati; Venticinque, Eduardo; Fine, Paul; Toledo, Marisol; Baraloto, Chris; Cerón, Carlos; Engel, Julien; Henkel, Terry W.; Jimenez, Eliana M.; Maas, Paul; Mora, Maria Cristina Peñuela; Petronelli, Pascal; Revilla, Juan David Cardenas; Silveira, Marcos; Stropp, Juliana; Thomas-Caesar, Raquel; Baker, Tim R.; Daly, Doug; Paredes, Marcos Ríos; da Silva, Naara Ferreira; Fuentes, Alfredo; Jørgensen, Peter Møller; Schöngart, Jochen; Silman, Miles R.; Arboleda, Nicolás Castaño; Cintra, Bruno Barçante Ladvocat; Valverde, Fernando Cornejo; Di Fiore, Anthony; Phillips, Juan Fernando; van Andel, Tinde R.; von Hildebrand, Patricio; Barbosa, Edelcilio Marques; de Matos Bonates, Luiz Carlos; de Castro, Deborah; de Sousa Farias, Emanuelle; Gonzales, Therany; Guillaumet, Jean-Louis; Hoffman, Bruce; Malhi, Yadvinder; de Andrade Miranda, Ires Paula; Prieto, Adriana; Rudas, Agustín; Ruschell, Ademir R.; Silva, Natalino; Vela, César I. A.; Vos, Vincent A.; Zent, Eglée L.; Zent, Stanford; Cano, Angela; Nascimento, Marcelo Trindade; Oliveira, Alexandre A.; Ramirez-Angulo, Hirma; Ramos, José Ferreira; Sierra, Rodrigo; Tirado, Milton; Medina, Maria Natalia Umaña; van der Heijden, Geertje; Torre, Emilio Vilanova; Vriesendorp, Corine; Wang, Ophelia; Young, Kenneth R.; Baider, Claudia; Balslev, Henrik; de Castro, Natalia; Farfan-Rios, William; Ferreira, Cid; Mendoza, Casimiro; Mesones, Italo; Torres-Lezama, Armando; Giraldo, Ligia Estela Urrego; Villarroel, Daniel; Zagt, Roderick; Alexiades, Miguel N.; Garcia-Cabrera, Karina; Hernandez, Lionel; Huamantupa-Chuquimaco, Isau; Milliken, William; Cuenca, Walter Palacios; Pansini, Susamar; Pauletto, Daniela; Arevalo, Freddy Ramirez; Sampaio, Adeilza Felipe; Valderrama Sandoval, Elvis H.; Gamarra, Luis Valenzuela</p> <p>2015-01-01</p> <p>Estimates of extinction risk for Amazonian plant and animal species are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian tree species are likely to qualify as globally threatened under International Union for Conservation of Nature (IUCN) Red List criteria. If confirmed, these results would increase the number of threatened plant species on Earth by 22%. We show that the trends observed in Amazonia apply to trees throughout the tropics, and we predict that most of the world’s >40,000 tropical tree species now qualify as globally threatened. A gap analysis suggests that existing Amazonian protected areas and indigenous territories will protect viable populations of most threatened species if these areas suffer no further degradation, highlighting the key roles that protected areas, indigenous peoples, and improved governance can play in preventing large-scale extinctions in the tropics in this century. PMID:26702442</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3521737','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3521737"><span>Distinct Microbial Limitations in Litter and Underlying Soil Revealed by Carbon and Nutrient Fertilization in a Tropical Rainforest</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Fanin, Nicolas; Barantal, Sandra; Fromin, Nathalie; Schimann, Heidy; Schevin, Patrick; Hättenschwiler, Stephan</p> <p>2012-01-01</p> <p>Human-caused alterations of the carbon and nutrient cycles are expected to impact tropical ecosystems in the near future. Here we evaluated how a combined change in carbon (C), nitrogen (N) and phosphorus (P) availability affects soil and litter microbial respiration and litter decomposition in an undisturbed Amazonian rainforest in French Guiana. In a fully factorial C (as cellulose), N (as urea), and P (as phosphate) fertilization experiment we analyzed a total of 540 litterbag-soil pairs after a 158-day exposure in the field. Rates of substrate-induced respiration (SIR) measured in litter and litter mass loss were similarly affected by fertilization showing the strongest stimulation when N and P were added simultaneously. The stimulating NP effect on litter SIR increased considerably with increasing initial dissolved organic carbon (DOC) concentrations in litter, suggesting that the combined availability of N, P, and a labile C source has a particularly strong effect on microbial activity. Cellulose fertilization, however, did not further stimulate the NP effect. In contrast to litter SIR and litter mass loss, soil SIR was reduced with N fertilization and showed only a positive effect in response to P fertilization that was further enhanced with additional C fertilization. Our data suggest that increased nutrient enrichment in the studied Amazonian rainforest can considerably change microbial activity and litter decomposition, and that these effects differ between the litter layer and the underlying soil. Any resulting change in relative C and nutrient fluxes between the litter layer and the soil can have important consequences for biogeochemical cycles in tropical forest ecosystems. PMID:23272052</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017E%26PSL.479...50H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017E%26PSL.479...50H"><span>Response of the Amazon rainforest to late Pleistocene climate variability</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Häggi, Christoph; Chiessi, Cristiano M.; Merkel, Ute; Mulitza, Stefan; Prange, Matthias; Schulz, Michael; Schefuß, Enno</p> <p>2017-12-01</p> <p>Variations in Amazonian hydrology and forest cover have major consequences for the global carbon and hydrological cycles as well as for biodiversity. Yet, the climate and vegetation history of the lowland Amazon basin and its effect on biogeography remain debated due to the scarcity of suitable high-resolution paleoclimate records. Here, we use the isotopic composition (δD and δ13C) of plant-waxes from a high-resolution marine sediment core collected offshore the Amazon River to reconstruct the climate and vegetation history of the integrated lowland Amazon basin for the period from 50,000 to 12,800 yr before present. Our results show that δD values from the Last Glacial Maximum were more enriched than those from Marine Isotope Stage (MIS) 3 and the present-day. We interpret this trend to reflect long-term changes in precipitation and atmospheric circulation, with overall drier conditions during the Last Glacial Maximum. Our results thus suggest a dominant glacial forcing of the climate in lowland Amazonia. In addition to previously suggested thermodynamic mechanisms of precipitation change, which are directly related to temperature, we conclude that changes in atmospheric circulation are crucial to explain the temporal evolution of Amazonian rainfall variations, as demonstrated in climate model experiments. Our vegetation reconstruction based on δ13C values shows that the Amazon rainforest was affected by intrusions of savannah or more open vegetation types in its northern sector during Heinrich Stadials, while it was resilient to glacial drying. This suggests that biogeographic patterns in tropical South America were affected by Heinrich Stadials in addition to glacial-interglacial climate variability.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25002502','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25002502"><span>Environmental impact of geometric earthwork construction in pre-Columbian Amazonia.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Carson, John Francis; Whitney, Bronwen S; Mayle, Francis E; Iriarte, José; Prümers, Heiko; Soto, J Daniel; Watling, Jennifer</p> <p>2014-07-22</p> <p>There is considerable controversy over whether pre-Columbian (pre-A.D. 1492) Amazonia was largely "pristine" and sparsely populated by slash-and-burn agriculturists, or instead a densely populated, domesticated landscape, heavily altered by extensive deforestation and anthropogenic burning. The discovery of hundreds of large geometric earthworks beneath intact rainforest across southern Amazonia challenges its status as a pristine landscape, and has been assumed to indicate extensive pre-Columbian deforestation by large populations. We tested these assumptions using coupled local- and regional-scale paleoecological records to reconstruct land use on an earthwork site in northeast Bolivia within the context of regional, climate-driven biome changes. This approach revealed evidence for an alternative scenario of Amazonian land use, which did not necessitate labor-intensive rainforest clearance for earthwork construction. Instead, we show that the inhabitants exploited a naturally open savanna landscape that they maintained around their settlement despite the climatically driven rainforest expansion that began ∼2,000 y ago across the region. Earthwork construction and agriculture on terra firme landscapes currently occupied by the seasonal rainforests of southern Amazonia may therefore not have necessitated large-scale deforestation using stone tools. This finding implies far less labor--and potentially lower population density--than previously supposed. Our findings demonstrate that current debates over the magnitude and nature of pre-Columbian Amazonian land use, and its impact on global biogeochemical cycling, are potentially flawed because they do not consider this land use in the context of climate-driven forest-savanna biome shifts through the mid-to-late Holocene.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4496080','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4496080"><span>Diverse Early Life-History Strategies in Migratory Amazonian Catfish: Implications for Conservation and Management</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hegg, Jens C.; Giarrizzo, Tommaso; Kennedy, Brian P.</p> <p>2015-01-01</p> <p>Animal migrations provide important ecological functions and can allow for increased biodiversity through habitat and niche diversification. However, aquatic migrations in general, and those of the world’s largest fish in particular, are imperiled worldwide and are often poorly understood. Several species of large Amazonian catfish carry out some of the longest freshwater fish migrations in the world, travelling from the Amazon River estuary to the Andes foothills. These species are important apex predators in the main stem rivers of the Amazon Basin and make up the region’s largest fishery. They are also the only species to utilize the entire Amazon Basin to complete their life cycle. Studies indicate both that the fisheries may be declining due to overfishing, and that the proposed and completed dams in their upstream range threaten spawning migrations. Despite this, surprisingly little is known about the details of these species’ migrations, or their life history. Otolith microchemistry has been an effective method for quantifying and reconstructing fish migrations worldwide across multiple spatial scales and may provide a powerful tool to understand the movements of Amazonian migratory catfish. Our objective was to describe the migratory behaviors of the three most populous and commercially important migratory catfish species, Dourada (Brachyplatystoma rousseauxii), Piramutaba (Brachyplatystoma vaillantii), and Piraíba (Brachyplatystoma filamentosum). We collected fish from the mouth of the Amazon River and the Central Amazon and used strontium isotope signatures (87Sr/86Sr) recorded in their otoliths to determine the location of early rearing and subsequent. Fish location was determined through discriminant function classification, using water chemistry data from the literature as a training set. Where water chemistry data was unavailable, we successfully in predicted 87Sr/86Sr isotope values using a regression-based approach that related the geology of the upstream watershed to the Sr isotope ratio. Our results provide the first reported otolith microchemical reconstruction of Brachyplatystoma migratory movements in the Amazon Basin. Our results indicate that juveniles exhibit diverse rearing strategies, rearing in both upstream and estuary environments. This contrasts with the prevailing understanding that juveniles rear in the estuary before migrating upstream; however, it is supported by some fisheries data that has indicated the presence of alternate spawning and rearing life-histories. The presence of alternate juvenile rearing strategies may have important implications for conservation and management of the fisheries in the region. PMID:26153984</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19860019071','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19860019071"><span>Origin and evolution of the Amazonian craton</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gibbs, A. K.; Wirth, K. R.</p> <p>1986-01-01</p> <p>The Amazonian craton appears to be formed and modifed by processes much like those of the better-known Precambrian cratons, but the major events did not always follow conventional sequences nor did they occur synchronously with those of other cratons. Much of the craton's Archean style continental crust formation, recorded in granite-greenstone and high-grade terranes, occurred in the Early Proterozoic: a period of relative quiescence in many other Precambrian regions. The common Archean to Proterozoic transition in geological style did not occur here, but an analogous change from abundant marine volcanism to dominantly continental sedimentary and eruptive styles occurred later. Amazonian geology is summarized, explaining the evolution of the craton.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=Change+AND+climate&pg=5&id=EJ1124316','ERIC'); return false;" href="https://eric.ed.gov/?q=Change+AND+climate&pg=5&id=EJ1124316"><span>Southern Foresters' Perceptions of Climate Change: Implications for Educational Program Development</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Boby, Leslie; Hubbard, William; Megalos, Mark; Morris, Hilary L. C.</p> <p>2016-01-01</p> <p>An understanding of foresters' perceptions of climate change is important for developing effective educational programs on adaptive forest management. We surveyed 1,398 foresters in the southern United States regarding their perceptions of climate change, observations and concerns about climatic and forest conditions, and knowledge of and interest…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/32462','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/32462"><span>Forest structure and downed woody debris in boreal temperate, and tropical forest fragments</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>William A. Gould; Grizelle Gonzalez; Andrew T. Hudak; Teresa Nettleton Hollingsworth; Jamie Hollingsworth</p> <p>2008-01-01</p> <p>Forest fragmentation affects the heterogeneity of accumulated fuels by increasing the diversity of forest types and by increasing forest edges. This heterogeneity has implications in how we manage fuels, fire, and forests. Understanding the relative importance of fragmentation on woody biomass within a single climatic regime, and along climatic gradients, will improve...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/27196','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/27196"><span>Forest environmental investments and implications for climate change mitigation.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Ralph J. Alig; Lucas S. Bair</p> <p>2006-01-01</p> <p>Forest environmental conditions are affected by climate change, but investments in forest environmental quality can be used as part of the climate change mitigation strategy. A key question involving the potential use of forests to store more carbon as part of climate change mitigation is the impact of forest investments on the timing and quantity of forest volumes...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16922310','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16922310"><span>The growth-defense trade-off and habitat specialization by plants in Amazonian forests.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fine, Paul V A; Miller, Zachariah J; Mesones, Italo; Irazuzta, Sebastian; Appel, Heidi M; Stevens, M Henry H; Sääksjärvi, Ilari; Schultz, Jack C; Coley, Phyllis D</p> <p>2006-07-01</p> <p>Tropical forests include a diversity of habitats, which has led to specialization in plants. Near Iquitos, in the Peruvian Amazon, nutrient-rich clay forests surround nutrient-poor white-sand forests, each harboring a unique composition of habitat specialist trees. We tested the hypothesis that the combination of impoverished soils and herbivory creates strong natural selection for plant defenses in white-sand forest, while rapid growth is favored in clay forests. Recently, we reported evidence from a reciprocal-transplant experiment that manipulated the presence of herbivores and involved 20 species from six genera, including phylogenetically independent pairs of closely related white-sand and clay specialists. When protected from herbivores, clay specialists exhibited faster growth rates than white-sand specialists in both habitats. But, when unprotected, white-sand specialists outperformed clay specialists in white-sand habitat, and clay specialists outperformed white-sand specialists in clay habitat. Here we test further the hypothesis that the growth defense trade-off contributes to habitat specialization by comparing patterns of growth, herbivory, and defensive traits in these same six genera of white-sand and clay specialists. While the probability of herbivore attack did not differ between the two habitats, an artificial defoliation experiment showed that the impact of herbivory on plant mortality was significantly greater in white-sand forests. We quantified the amount of terpenes, phenolics, leaf toughness, and available foliar protein for the plants in the experiment. Different genera invested in different defensive strategies, and we found strong evidence for phylogenetic constraint in defense type. Overall, however, we found significantly higher total defense investment for white-sand specialists, relative to their clay specialist congeners. Furthermore, herbivore resistance consistently exhibited a significant trade-off against growth rate in each of the six phylogenetically independent species-pairs. These results confirm theoretical predictions that a trade-off exists between growth rate and defense investment, causing white-sand and clay specialists to evolve divergent strategies. We propose that the growth-defense trade-off is universal and provides an important mechanism by which herbivores govern plant distribution patterns across resource gradients.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.B11G0128K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.B11G0128K"><span>Public policies and communication affecting forest cover in the Amazon</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kawakami Savaget, E.; Batistella, M.; Aguiar, A. P. D.</p> <p>2014-12-01</p> <p>The research program Amazalert was based on information delivered by the IPCC through its 2007 report, which indicates forest degradation processes in the Amazonian region as a consequence of anthropogenic actions. Such processes affecting the structural and functional characteristics of ecosystems would harm environmental services that guarantee, for example, the regulation of climate and the provision of fresh water. A survey was organized, through a multidisciplinary perspective, on the main policies and programs that can affect forest cover in the Amazon. These rules and norms seek to regulate societal actions by defining a developmental model for the region. Although deforestation rates in the Brazilian Amazon have decreased significantly since 2004, some locations maintain high levels of deforestation. In 2013, for example, the municipalities of Monte Alegre, Óbidos, Alenquer, Oriximiná, Curuá and Almeirin, in the northern region of the state of Para, showed the highest rates of deforestation in the Amazon. Managers and stakeholders within these areas are being interviewed to provide insights on how policies are interpreted and applied locally. There is an understanding delay between discourses normalized by federal governmental institutions and claims of local societies. The possible lack of clarity in official discourses added to the absence of a local communicative dynamics cause the phenomenon of incomplete information. Conflicts often occur in local institutional arenas resulting in violence and complex social and historical dissonances, enhanced by other public policies idealized in different temporal and spatial conditions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.B33G0692K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.B33G0692K"><span>Glacial/Interglacial climate and vegetation history of North-East of Brazil during the last 1.5 Ma and their connection to the Amazonian rainforest</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kern, A.; Baker, P. A.; Cruz, F. W., Sr.; Dwyer, G. S.; Silva, C. G.; Oliveira, A. S.; Willard, D. A.</p> <p>2016-12-01</p> <p>Northeastern (NE) Brazil is characterized today by a dry climate and vegetation, which separate the humid forests of the Amazonia from those along the Atlantic coast. Species composition and molecular genetics suggest phases of exchange between these forests in the past and the NE region is the most likely corridor for migration. However, the vegetation history of the NE is largely unknown, leaving questions on the impact of glacial stages on the forest composition and the timing of cyclic transitions from tropical rainforest to semi-arid vegetation or vice versa. Here, we present preliminary results from a marine record recovered from the equatorial Brazilian continental margin covering the last 1.5 Ma. Pollen-based reconstructions across several glacial and interglacial stages provide data on vegetation expansion and retraction of these different biomes. Vegetation changes during drying/cooling events in the NE, which may be linked to movements of the Inter Tropical Convergence Zone or/and intensities of the South American Monsoon System. Increases in terrestrial input to the core site during these climatic events may be of NE origin or Amazon origin. In the latter case, these increases would mark a decrease or reversal of the strength of the North Brazil Current. This study is funded by FAPESP projects 2015/18314-7, 2014/05582-0 and the FAPESPBIOTA/NSF-Dimensions project 2012/50260-6).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4234539','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4234539"><span>Vegetation dynamics and rainfall sensitivity of the Amazon</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hilker, Thomas; Lyapustin, Alexei I.; Tucker, Compton J.; Hall, Forrest G.; Myneni, Ranga B.; Wang, Yujie; Bi, Jian; Mendes de Moura, Yhasmin; Sellers, Piers J.</p> <p>2014-01-01</p> <p>We show that the vegetation canopy of the Amazon rainforest is highly sensitive to changes in precipitation patterns and that reduction in rainfall since 2000 has diminished vegetation greenness across large parts of Amazonia. Large-scale directional declines in vegetation greenness may indicate decreases in carbon uptake and substantial changes in the energy balance of the Amazon. We use improved estimates of surface reflectance from satellite data to show a close link between reductions in annual precipitation, El Niño southern oscillation events, and photosynthetic activity across tropical and subtropical Amazonia. We report that, since the year 2000, precipitation has declined across 69% of the tropical evergreen forest (5.4 million km2) and across 80% of the subtropical grasslands (3.3 million km2). These reductions, which coincided with a decline in terrestrial water storage, account for about 55% of a satellite-observed widespread decline in the normalized difference vegetation index (NDVI). During El Niño events, NDVI was reduced about 16.6% across an area of up to 1.6 million km2 compared with average conditions. Several global circulation models suggest that a rise in equatorial sea surface temperature and related displacement of the intertropical convergence zone could lead to considerable drying of tropical forests in the 21st century. Our results provide evidence that persistent drying could degrade Amazonian forest canopies, which would have cascading effects on global carbon and climate dynamics. PMID:25349419</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170003716','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170003716"><span>Scaling Estimates of Vegetation Structure in Amazonian Tropical Forests Using Multi-Angle MODIS Observations</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mendes De Moura, Yhasmin; Hilker, Thomas; Goncalves, Fabio Guimaraes; Galvao, Lenio Soares; Roberto dos Santos, Joao; Lyapustin, Alexei; Maeda, Eduardo Eiji; de Jesus Silva, Camila Valeria</p> <p>2016-01-01</p> <p>Detailed knowledge of vegetation structure is required for accurate modelling of terrestrial ecosystems, but direct measurements of the three dimensional distribution of canopy elements, for instance from LiDAR, are not widely available. We investigate the potential for modelling vegetation roughness, a key parameter for climatological models, from directional scattering of visible and near-infrared (NIR) reflectance acquired from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS). We compare our estimates across different tropical forest types to independent measures obtained from: (1) airborne laser scanning (ALS), (2) spaceborne Geoscience Laser Altimeter System (GLAS)/ICESat, and (3) the spaceborne SeaWinds/QSCAT. Our results showed linear correlation between MODIS-derived anisotropy to ALS-derived entropy (r(exp 2)= 0.54, RMSE= 0.11), even in high biomass regions. Significant relationships were also obtained between MODIS-derived anisotropy and GLAS-derived entropy(0.52 less than or equal to r(exp 2) less than or equal to 0.61; p less than 0.05), with similar slopes and offsets found throughout the season, and RMSE between 0.26 and 0.30 (units of entropy). The relationships between the MODIS-derived anisotropy and backscattering measurements (sigma(sup 0)) from SeaWinds/QuikSCAT presented an r(exp 2) of 0.59 and a RMSE of 0.11. We conclude that multi-angular MODIS observations are suitable to extrapolate measures of canopy entropy across different forest types, providing additional estimates of vegetation structure in the Amazon.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..1413778S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..1413778S"><span>Response of Tropical Forests to Intense Climate Variability and Rainfall Anomaly over the Last Decade</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saatchi, S.; Asefi, S.</p> <p>2012-04-01</p> <p>During the last decade, strong precipitation anomalies resulted from increased sea surface temperature in the tropical Atlantic, have caused extensive drying trends in rainforests of western Amazonia, exerting water stress, tree mortality, biomass loss, and large-scale fire disturbance. In contrast, there have been no reports on large-scale disturbance in rainforests of west and central Africa, though being exposed to similar intensity of climate variability. Using data from Tropical Rainfall Mapping Mission (TRMM) (1999-2010), and time series of rainfall observations from meteorological stations (1971-2000), we show that both Amazonian and African rainforest experienced strong precipitation anomalies from 2005-2010. We monitored the response of forest to the climate variability by analyzing the canopy water content observed by SeaWinds Ku-band Scatterometer (QSCAT) (1999-2009) and found that more than 70 million ha of forests in western Amazonia experienced a strong water deficit during the dry season of 2005 and a closely corresponding decline in canopy backscatter that persisted until the next major drought in 2010. This decline in backscatter has been attributed to loss of canopy water content and large-scale tree mortality corroborated by ground and airborne observations. However, no strong impacts was observed on tropical forests of Africa, suggesting that the African rainforest may have more resilience to droughts. We tested this hypothesis by examining the seasonal rainfall patterns, maximum water deficit, and the surface temperature variations. Results show that there is a complex pattern of low annual rainfall, moderate seasonality, and lower surface temperature in Central Africa compared to Amazonia, indicating potentially a lower evapotranspiration circumventing strong water deficits</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.B23C0442S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.B23C0442S"><span>Response of Tropical Forests to Intense Climate Variability and Rainfall Anomaly of Last Decade</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saatchi, S. S.; Asefi Najafabady, S.</p> <p>2011-12-01</p> <p>During the last decade, strong precipitation anomalies resulted from increased sea surface temperature in the tropical Atlantic, have caused extensive drying trends in rainforests of western Amazonia, exerting water stress, tree mortality, biomass loss, and large-scale fire disturbance. In contrast, there have been no reports on large-scale disturbance in rainforests of west and central Africa, though being exposed to similar intensity of climate variability. Using data from Tropical Rainfall Mapping Mission (TRMM) (1999-2010), and time series of rainfall observations from meteorological stations (1971-2000), we show that both Amazonian and African rainforest experienced strong precipitation anomalies from 2005-2010. We monitored the response of forest to the climate variability by analyzing the canopy water content observed by SeaWinds Ku-band Scatterometer (QSCAT) (1999-2009) and found that more than 70 million ha of forests in western Amazonia experienced a strong water deficit during the dry season of 2005 and a closely corresponding decline in canopy backscatter that persisted until the next major drought in 2010. This decline in backscatter has been attributed to loss of canopy water content and large-scale tree mortality corroborated by ground and airborne observations. However, no strong impacts was observed on tropical forests of Africa, suggesting that the African rainforest may have more resilience to droughts. We tested this hypothesis by examining the seasonal rainfall patterns, maximum water deficit, and the surface temperature variations. Results show that there is a complex pattern of low annual rainfall, moderate seasonality, and lower surface temperature in Central Africa compared to Amazonia, indicating potentially a lower evapotranspiration circumventing strong water deficits.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.B11A0397M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.B11A0397M"><span>Isotopic analysis of Bothrops atrox in Amazonian forest</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Martinez, M. G.; Silva, A. M.; Chalkidis, H.; de Oliveira Júnior, R. C.; Camargo, P. B.</p> <p>2012-12-01</p> <p>The poisoning of snakes is considered a public health problem, especially in populations from rural areas of tropical and subtropical countries. In Brazil, the 26,000 snakebites, 90% are of the genus Bothrops, and Bothrops atrox species predominant in the Amazon region including all the Brazilian Amazon. Research shows that using stable isotopes, we can verify the isotopic composition of tissues of animals that depend mainly on food, water ingested and inhaled gases. For this study, samples taken from Bothrops atrox (B. atrox), in forest using pitfall traps and fall ("Pitt-fall traps with drift fence"). The analyzes were performed by mass spectrometry, where the analytical error is 0.3‰ for carbon and 0.5‰ to nitrogen. The results of the forest animals are significantly different from results of animal vivarium. The average values of the tissues and venoms of snakes of the forest for carbon-13 and nitrogen-15 are: δ13C = -24.68‰ and δ15N = 14.22‰ and mean values of tissue and poisons snakes vivarium (Instituto Butantan) to carbon-13 and nitrogen-15 are δ13C = -20.47‰ and δ15N = 8.36‰, with a significantly different due to different sources of food animals. Based on all results isotopic δ13C and δ15N, we can suggest that changes as the power of the serpent, (nature and captivity), changes occur in relation to diet and environment as the means of the isotopic data are quite distinct, showing that these changes can also cause metabolic changes in the body of the animal itself and the different periods of turnover of each tissue analyzed.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H31F1473G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H31F1473G"><span>The Effect of Drought on Stomatal Conductance in the Biosphere 2 Rainforest</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gay, J. D.; Van Haren, J. L. M.</p> <p>2015-12-01</p> <p>Drought is a major climate change concern for the Earth's rainforests; however little is currently known about how these forests and individual plants will respond to water stress. At the individual level, the ability of plants to regulate their stomatal conductance is an important preservation mechanism that helps to cool leaves, regulate water loss, and uptake carbon dioxide. At the ecosystem level, transpiration in rainforests is a major contributor to the positive feedback loop that returns moisture to the atmosphere for continued precipitation cycles. Nearly 60% of atmospheric moisture in the Amazon rain forests has been traced back to origins of transpiration from its plants. In relation to current climatic conditions, stomatal conductance rates are highly variable across rainforest species and environmental conditions. It is still unknown to what extent these rates will decrease at leaf and forest level in response to periods of drought. The University of Arizona's Biosphere 2 (B2) served as the study site for a simulated 4-week long drought because of its ability to mimic the micrometeorology of an Amazonian rainforest. Three species of plants were chosen at various levels in the canopy: Clitoria racemosa, Cissus sicyoides, and Hibiscus elatus. These plants were selected based on their relative abundance and distribution in the B2 forest. It was revealed that two out of the three species exhibited decreases in H20 efflux at each elevation, while one species (C. racemosa) proved much more resistant, at each elevation, to H20 loss. These results may be useful for future integrative modeling of how individual leaf level responses extend to entire ecosystem scales. It will be important to better understand how rainforests conserve, recycle, and lose water to gauge their response to warming climate, and increased periods of drought in the tropics.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25809788','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25809788"><span>Soil microbiome responses to the short-term effects of Amazonian deforestation.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Navarrete, Acacio A; Tsai, Siu M; Mendes, Lucas W; Faust, Karoline; de Hollander, Mattias; Cassman, Noriko A; Raes, Jeroen; van Veen, Johannes A; Kuramae, Eiko E</p> <p>2015-05-01</p> <p>Slash-and-burn clearing of forest typically results in increase in soil nutrient availability. However, the impact of these nutrients on the soil microbiome is not known. Using next generation sequencing of 16S rRNA gene and shotgun metagenomic DNA, we compared the structure and the potential functions of bacterial community in forest soils to deforested soils in the Amazon region and related the differences to soil chemical factors. Deforestation decreased soil organic matter content and factors linked to soil acidity and raised soil pH, base saturation and exchangeable bases. Concomitant to expected changes in soil chemical factors, we observed an increase in the alpha diversity of the bacterial microbiota and relative abundances of putative copiotrophic bacteria such as Actinomycetales and a decrease in the relative abundances of bacterial taxa such as Chlamydiae, Planctomycetes and Verrucomicrobia in the deforested soils. We did not observe an increase in genes related to microbial nutrient metabolism in deforested soils. However, we did observe changes in community functions such as increases in DNA repair, protein processing, modification, degradation and folding functions, and these functions might reflect adaptation to changes in soil characteristics due to forest clear-cutting and burning. In addition, there were changes in the composition of the bacterial groups associated with metabolism-related functions. Co-occurrence microbial network analysis identified distinct phylogenetic patterns for forest and deforested soils and suggested relationships between Planctomycetes and aluminium content, and Actinobacteria and nitrogen sources in Amazon soils. The results support taxonomic and functional adaptations in the soil bacterial community following deforestation. We hypothesize that these microbial adaptations may serve as a buffer to drastic changes in soil fertility after slash-and-burning deforestation in the Amazon region. © 2015 John Wiley & Sons Ltd.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24061084','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24061084"><span>Assessing the extent of "conflict of use" in multipurpose tropical forest trees: a regional view.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Herrero-Jáuregui, Cristina; Guariguata, Manuel R; Cárdenas, Dairon; Vilanova, Emilio; Robles, Marco; Licona, Juan Carlos; Nalvarte, Walter</p> <p>2013-11-30</p> <p>In the context of multiple forest management, multipurpose tree species which provide both timber and non-timber forest products (NTFP), present particular challenges as the potential of conflicting use for either product may be high. One key aspect is that the magnitude of conflict of use can be location specific, thus adding complexity to policy development. This paper focuses on the extent to which the potential for conflict of use in multipurpose tree species varies across the Amazonian lowland forests shared by Peru, Bolivia, Colombia, Ecuador and Venezuela, emphasizing the economic dimension of conflict. Based on a review of the current normative and regulatory aspects of timber and NTFP extraction in the five countries, the paper also briefly discusses the opportunities and constraints for harmonization of timber and NTFP management of multipurpose species across the region. It was found that about half of the 336 timber species reviewed across the five countries also have non-timber uses. Eleven timber species are multipurpose in all five countries: Calophyllum brasiliense, Cedrela odorata, Ceiba pentandra, Clarisia racemosa, Ficus insipida, Jacaranda copaia, Schefflera morototoni, Simarouba amara and Terminalia amazonia. Seven other multipurpose species occurred only in either Venezuela (Tabebuia impetiginosa, Spondias mombin, Pentaclethra macroloba, Copaifera officinalis, Chlorophora tinctoria, Carapa guianensis) or Ecuador (Tabebuia chrysantha). Four multipurpose tree species presented the highest potential of conflict of use across the region: Dipteryx odorata, Tabebuia serratifolia, Hymenaea courbaril and Myroxylon balsamum yet these were not evenly distributed across all five countries. None of the five studied countries have specific legislation to promote sustainable use of any of the multipurpose species reported here and thus mitigate potential conflict of use; nor documented management options for integration or else segregation of both their timber and NTFP values. Copyright © 2013 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.B54C..05N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.B54C..05N"><span>Fine-Scale Relief in the Amazon Drives Large Scale Ecohydrological Processes</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nobre, A. D.; Cuartas, A.; Hodnett, M.; Saleska, S. R.</p> <p>2014-12-01</p> <p>Access to soil water by roots is a key ecophysiological factor for plant productivity in natural systems. Periodically during dry seasons or critically during episodic climate droughts, shortage of water supply can reduce or severely impair plant life. At the other extreme persistent soil waterlogging will limit root respiration and restrict local establishment to adapted species, usually leading to stunted and less productive communities. Soil-water availability is therefore a very important climate variable controlling plant physiology and ecosystem dynamics. Terra-firme, the non-seasonally floodable terrain that covers 82% of the landscape in Amazonia,[1] supports the most massive part of the rainforest ecosystem. The availability of soil water data for terra-firme is scant and very coarse. This lack of data has hampered observational and modeling studies aiming to develop a large-scale integrative ecohydrological picture of Amazonia and its vulnerability to climate change. We have mapped the Amazon basin with a new terrain model developed in our group (HAND, Height Above the Nearest drainage[2]), delineating soil water environments using topographical data from the SRTM digital elevation model (250 m horizontal interpolated resolution). The preliminary results show that more than 50% of Terra-firme has the water table very close to the surface (up to 2 m deep), while the remainder of the upland landscape has variable degree of dependence on non-saturated soil (vadose layer). The mapping also shows extremely heterogeneous patterns of fine-scale relief across the basin, which implies complex ecohydrological regional forcing on the forest physiology. Ecoclimate studies should therefore take into account fine-scale relief and its implications for soil-water availability to plant processes. [1] Melack, J. M., & Hess, L. L. (2011). Remote sensing of the distribution and extent of wetlands in the Amazon basin. In W. J. Junk & M. Piedade (Eds.), Amazonian floodplain forests: Ecophysiology, ecology, biodiversity and sustainable management (pp. 1-28). Ecological Studies-Springer. [2] Nobre, A. D., Cuartas, L. A., Hodnett, M., … Saleska, S. (2011). Height Above the Nearest Drainage - a hydrologically relevant new terrain model. Journal of Hydrology, 404(1-2), 13-29</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1569459','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1569459"><span>Tropical forest cover change in the 1990s and options for future monitoring</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Mayaux, Philippe; Holmgren, Peter; Achard, Frédéric; Eva, Hugh; Stibig, Hans-Jürgen; Branthomme, Anne</p> <p>2005-01-01</p> <p>Despite the importance of the world's humid tropical forests, our knowledge concerning their rates of change remains limited. Two recent programmes (FAO 2000 Forest Resources Assessment and TREES II), exploiting the global imaging capabilities of Earth observing satellites, have recently been completed to provide information on the dynamics of tropical forest cover. The results from these independent studies show a high degree of conformity and provide a good understanding of trends at the pan-tropical level. In 1990 there were some 1150 million ha of tropical rain forest with the area of the humid tropics deforested annually estimated at 5.8 million ha (approximately twice the size of Belgium). A further 2.3 million ha of humid forest is apparently degraded annually through fragmentation, logging and/or fires. In the sub-humid and dry tropics, annual deforestation of tropical moist deciduous and tropical dry forests comes to 2.2 and 0.7 million ha, respectively. Southeast Asia is the region where forests are under the highest pressure with an annual change rate of −0.8 to −0.9%. The annual area deforested in Latin America is large, but the relative rate (−0.4 to −0.5%) is lower, owing to the vast area covered by the remaining Amazonian forests. The humid forests of Africa are being converted at a similar rate to those of Latin America (−0.4 to −0.5% per year). During this period, secondary forests have also been established, through re-growth on abandoned land and forest plantations, but with different ecological, biophysical and economic characteristics compared with primary forests. These trends are significant in all regions, but the extent of new forest cover has proven difficult to establish. These results, as well as the lack of more detailed knowledge, clearly demonstrate the need to improve sound scientific evidence to support policy. The two projects provide useful guidance for future monitoring efforts in the context of multilateral environmental agreements and of international aid, trade and development partnerships. Methodologically, the use of high-resolution remote sensing in representative samples has been shown to be cost-effective. Close collaboration between tropical institutions and inter-governmental organizations proved to be a fruitful arrangement in the different projects. To properly assist decision-making, monitoring and assessments should primarily be addressed at the national level, which also corresponds to the ratification level of the multilateral environmental agreements. The Forest Resources Assessment 2000 deforestation statistics from countries are consistent with the satellite-based estimates in Asia and America, but are significantly different in Africa, highlighting the particular need for long-term capacity-building activities in this continent. PMID:15814351</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15814351','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15814351"><span>Tropical forest cover change in the 1990s and options for future monitoring.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mayaux, Philippe; Holmgren, Peter; Achard, Frédéric; Eva, Hugh; Stibig, Hans-Jürgen; Branthomme, Anne</p> <p>2005-02-28</p> <p>Despite the importance of the world's humid tropical forests, our knowledge concerning their rates of change remains limited. Two recent programmes (FAO 2000 Forest Resources Assessment and TREES II), exploiting the global imaging capabilities of Earth observing satellites, have recently been completed to provide information on the dynamics of tropical forest cover. The results from these independent studies show a high degree of conformity and provide a good understanding of trends at the pan-tropical level. In 1990 there were some 1150 million ha of tropical rain forest with the area of the humid tropics deforested annually estimated at 5.8 million ha (approximately twice the size of Belgium). A further 2.3 million ha of humid forest is apparently degraded annually through fragmentation, logging and/or fires. In the sub-humid and dry tropics, annual deforestation of tropical moist deciduous and tropical dry forests comes to 2.2 and 0.7 million ha, respectively. Southeast Asia is the region where forests are under the highest pressure with an annual change rate of -0.8 to -0.9%. The annual area deforested in Latin America is large, but the relative rate (-0.4 to -0.5%) is lower, owing to the vast area covered by the remaining Amazonian forests. The humid forests of Africa are being converted at a similar rate to those of Latin America (-0.4 to -0.5% per year). During this period, secondary forests have also been established, through re-growth on abandoned land and forest plantations, but with different ecological, biophysical and economic characteristics compared with primary forests. These trends are significant in all regions, but the extent of new forest cover has proven difficult to establish. These results, as well as the lack of more detailed knowledge, clearly demonstrate the need to improve sound scientific evidence to support policy. The two projects provide useful guidance for future monitoring efforts in the context of multilateral environmental agreements and of international aid, trade and development partnerships. Methodologically, the use of high-resolution remote sensing in representative samples has been shown to be cost-effective. Close collaboration between tropical institutions and inter-governmental organizations proved to be a fruitful arrangement in the different projects. To properly assist decision-making, monitoring and assessments should primarily be addressed at the national level, which also corresponds to the ratification level of the multilateral environmental agreements. The Forest Resources Assessment 2000 deforestation statistics from countries are consistent with the satellite-based estimates in Asia and America, but are significantly different in Africa, highlighting the particular need for long-term capacity-building activities in this continent.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/50796','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/50796"><span>Echohydrological implications of drought for forests in the United States</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>James M. Vose; Chelcy Ford Miniat; Charles H. Luce; Heidi Asbjornsen; Peter V. Caldwell; John L. Campbell; Gordon E. Grant; Daniel J. Isaak; Steven P. Loheide; Ge Sun</p> <p>2016-01-01</p> <p>The relationships among drought, surface water flow, and groundwater recharge are not straightforward for most forest ecosystems due to the strong role that vegetation plays in the forest water balance. Hydrologic responses to drought can be either mitigated or exacerbated by forest vegetation depending upon vegetation water use and how forest population dynamics...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/34967','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/34967"><span>Predicting forest successional stages using mutitemporal Landsat imagery with forest inventory and analysis data</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Weiguo Liu; Conghe Song; Todd A. Schroeder; Warren B. Cohen</p> <p>2008-01-01</p> <p>Forest succession is an important ecological process that has profound biophysical, biological and biogeochemical implications in terrestrial ecosystems. Therefore, information on forest successional stages over an extensive forested landscape is crucial for us to understand ecosystem processes, such as carbon assimilation and energy interception. This study explored...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/26956','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/26956"><span>Fire in Siberian boreal forests -- implications for global climate and air quality</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Eduard P. Davidenko</p> <p>1998-01-01</p> <p>Boreal forests and woodlands comprise about 29 percent of the world's forest cover. About 70 percent of this forest is in Eurasia, mostly in the Russian Federation. Boreal forests contain about 45 percent of the world's growing stock and are an increasingly important part of global timber production. Fire impacts large areas of boreal forest annually in...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26280812','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26280812"><span>The Tsimane' Amazonian Panel Study (TAPS): Nine years (2002-2010) of annual data available to the public.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Leonard, William R; Reyes-García, Victoria; Tanner, Susan; Rosinger, Asher; Schultz, Alan; Vadez, Vincent; Zhang, Rebecca; Godoy, Ricardo</p> <p>2015-12-01</p> <p>This brief communication contains a description of the 2002-2010 annual panel collected by the Tsimane' Amazonian Panel Study team. The study took place among the Tsimane', a native Amazonian society of forager-horticulturalists. The team tracked a wide range of socio-economic and anthropometric variables from all residents (633 adults ≥16 years; 820 children) in 13 villages along the Maniqui River, Department of Beni. The panel is ideally suited to examine how market exposure and modernization affect the well-being of a highly autarkic population and to examine human growth in a non-Western rural setting. Copyright © 2015 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/6240','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/6240"><span>Non-timber forest products enterprises in the south: perceived distribution and implications for sustainable forest management</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>J.L. Chamberlain; M. Predny</p> <p>2003-01-01</p> <p>Forests of the southern United States are the source of a great diversity of flora, much of which is gathered to produce non-timber forest products (NTFPs). These products are made from resources that grow under the forest canopy as trees, herbs, shrubs, vines, moss and even lichen. They occur naturally in forests or may be cultivated under the forest canopy or in...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/40783','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/40783"><span>Site productivity and forest carbon stocks in the United States: Analysis and implications for forest offset project planning</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Coeli M. Hoover; James E. Smith</p> <p>2012-01-01</p> <p>The documented role of United States forests in sequestering carbon, the relatively low cost of forest-based mitigation, and the many co-benefits of increasing forest carbon stocks all contribute to the ongoing trend in the establishment of forest-based carbon offset projects. We present a broad analysis of forest inventory data using site quality indicators to provide...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26312742','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26312742"><span>Litter mercury deposition in the Amazonian rainforest.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fostier, Anne Hélène; Melendez-Perez, José Javier; Richter, Larissa</p> <p>2015-11-01</p> <p>The objective of this work was to assess the flux of atmospheric mercury transferred to the soil of the Amazonian rainforest by litterfall. Calculations were based on a large survey of published and unpublished data on litterfall and Hg concentrations in litterfall samples from the Amazonian region. Litterfall based on 65 sites located in the Amazon rainforest averaged 8.15 ± 2.25 Mg ha(-1) y(-1). Average Hg concentrations were calculated from nine datasets for fresh tree leaves and ten datasets for litter, and a median concentration of 60.5 ng Hg g(-1) was considered for Hg deposition in litterfall, which averaged 49 ± 14 μg m(-2) yr(-1). This value was used to estimate that in the Amazonian rainforest, litterfall would be responsible for the annual removing of 268 ± 77 Mg of Hg, approximately 8% of the total atmospheric Hg deposition to land. The impact of the Amazon deforestation on the Hg biogeochemical cycle is also discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28095487','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28095487"><span>DNA Metabarcoding of Amazonian Ichthyoplankton Swarms.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Maggia, M E; Vigouroux, Y; Renno, J F; Duponchelle, F; Desmarais, E; Nunez, J; García-Dávila, C; Carvajal-Vallejos, F M; Paradis, E; Martin, J F; Mariac, C</p> <p>2017-01-01</p> <p>Tropical rainforests harbor extraordinary biodiversity. The Amazon basin is thought to hold 30% of all river fish species in the world. Information about the ecology, reproduction, and recruitment of most species is still lacking, thus hampering fisheries management and successful conservation strategies. One of the key understudied issues in the study of population dynamics is recruitment. Fish larval ecology in tropical biomes is still in its infancy owing to identification difficulties. Molecular techniques are very promising tools for the identification of larvae at the species level. However, one of their limits is obtaining individual sequences with large samples of larvae. To facilitate this task, we developed a new method based on the massive parallel sequencing capability of next generation sequencing (NGS) coupled with hybridization capture. We focused on the mitochondrial marker cytochrome oxidase I (COI). The results obtained using the new method were compared with individual larval sequencing. We validated the ability of the method to identify Amazonian catfish larvae at the species level and to estimate the relative abundance of species in batches of larvae. Finally, we applied the method and provided evidence for strong temporal variation in reproductive activity of catfish species in the Ucayalí River in the Peruvian Amazon. This new time and cost effective method enables the acquisition of large datasets, paving the way for a finer understanding of reproductive dynamics and recruitment patterns of tropical fish species, with major implications for fisheries management and conservation.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15847912','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15847912"><span>Diurnal biting periodicity of parous Simulium (Diptera: Simuliidae) vectors in the onchocerciasis Amazonian focus.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Grillet, M-E; Villamizar, N J; Cortez, J; Frontado, H L; Escalona, M; Vivas-Martínez, S; Basáñez, M-G</p> <p>2005-05-01</p> <p>We describe the hourly patterns of parous biting activity of the three main simuliid vectors of human onchocerciasis in the Amazonian focus straddling between Venezuela and Brazil, namely, Simulium guianense s.l. Wise; S. incrustatum Lutz, and S. oyapockense s.l. Floch and Abonnenc. Time series of the hourly numbers of host-seeking parous flies caught in five Yanomami villages during dry, rainy, and their transition periods from 1995 to 2001 were investigated using harmonic analysis (assuming an underlying circadian rhythm) and periodic correlation (based on Spearman's r). Parous S guianense s.l. showed a bimodal activity pattern, with a minor peak in mid-morning and a major peak at 16:00 h. S. incrustatum exhibited mainly unimodal activity during either early morning or midday according to locality. S. oyapockense s.l. bit humans throughout the day mainly between 10:00 and 16:00 h but also showed bimodal periodicity in some localities. Superimposed on the endogenous, species-specific daily cycles, parous activity showed variation according to locality, season, air temperature and relative humidity, with biting being promoted by warmer and drier hours during wet seasons/periods and reduced during hotter times in dry seasons or transitions. The results are discussed in terms of their implications for blackfly biology and ecology as well as onchocerciasis epidemiology and control.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27884213','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27884213"><span>Regional variation in Ascaris lumbricoides and Trichuris trichiura infections by age cohort and sex: effects of market integration among the indigenous Shuar of Amazonian Ecuador.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gildner, Theresa E; Cepon-Robins, Tara J; Liebert, Melissa A; Urlacher, Samuel S; Madimenos, Felicia C; Snodgrass, J Josh; Sugiyama, Lawrence S</p> <p>2016-11-24</p> <p>Soil-transmitted helminth (STH) infection peaks during childhood and varies by sex. The impact of market integration (MI) (increasing production for and consumption from a market-based economy) on these infection patterns, however, is unclear. In this study, STH infection is examined by sex and age among indigenous Shuar inhabiting two regions of Amazonian Ecuador: (1) the modestly market-integrated Upano Valley (UV) and (2) the more traditional Cross-Cutucú (CC) region. Kato-Katz fecal smears were examined for parasite presence and infection intensity. Factorial ANOVAs and post hoc simple effects analyses were performed by sex to compare infection intensity between regions and age categories (infant/child, juvenile/adolescent, adult). Significant age and regional differences in Ascaris lumbricoides and Trichuris trichiura infection were detected. Overall, infants/children and juveniles/adolescents displayed higher parasite loads than adults. CC females exhibited higher A. lumbricoides loads than UV females, while the opposite pattern was observed for T. trichiura infection in males. Regional infection patterns varied by sex and parasite species, perhaps due to MI-linked environmental and lifestyle changes. These results have public health implications for the identification of individuals at risk for infection and contribute to ongoing efforts to track changes and alleviate STH infection in indigenous populations undergoing MI.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2852522','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2852522"><span>Effect of Parathion-Methyl on Amazonian Fish and Freshwater Invertebrates: A Comparison of Sensitivity with Temperate Data</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Geber-Corrêa, Rachel; Campos, Paola S.; Garcia, Marcos V. B.; Waichman, Andrea V.; van den Brink, Paul J.</p> <p>2009-01-01</p> <p>Parathion-methyl is an organophosphorous insecticide that is widely used in agricultural production sites in the Amazon. The use of this pesticide might pose a potential risk for the biodiversity and abundance of fish and invertebrate species inhabiting aquatic ecosystems adjacent to the agricultural fields. Due to a lack of toxicity data for Amazonian species, safe environmental concentrations used to predict the ecological risks of parathion-methyl in the Amazon are based on tests performed with temperate species, although it is unknown whether the sensitivity of temperate species is representative for those of Amazonian endemic species. To address this issue, the acute toxic effect (LC50–96 h) of parathion-methyl was assessed on seven fish and five freshwater invertebrate species endemic to the Amazon. These data were used to compare their pesticide sensitivity with toxicity data for temperate species collected from the literature. The interspecies sensitivity was compared using the Species Sensitivity Distribution (SSD) concept. The results of this study suggest that Amazonian species are no more, or less, sensitive to parathion-methyl than their temperate counterparts, with LC50 values ranging from 2900 to 7270 μg/L for fish and from 0.3 to 319 μg/L for freshwater arthropods. Consequently, this evaluation supports the initial use of toxicity data of temperate fish and freshwater invertebrate species for assessing the effects of parathion-methyl on Amazonian freshwater ecosystems. PMID:19847472</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <div class="footer-extlink text-muted" style="margin-bottom:1rem; text-align:center;">Some links on this page may take you to non-federal websites. 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