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Sample records for lowland rain forest

  1. Tropical Rain Forest and Climate Dynamics of the Atlantic Lowland, Southern Brazil, during the Late Quaternary

    NASA Astrophysics Data System (ADS)

    Behling, Hermann; Negrelle, Raquel R. B.

    2001-11-01

    Palynological analysis of a core from the Atlantic rain forest region in Brazil provides unprecedented insight into late Quaternary vegetational and climate dynamics within this southern tropical lowland. The 576-cm-long sediment core is from a former beach-ridge "valley," located 3 km inland from the Atlantic Ocean. Radio-carbon dates suggest that sediment deposition began prior to 35,000 14C yr B.P. Between ca. 37,500 and ca. 27,500 14C yr B.P. and during the last glacial maximum (LGM; ca. 27,500 to ca. 14,500 14C yr B.P.), the coastal rain forest was replaced by grassland and patches of cold-adapted forest. Tropical trees, such as Alchornea, Moraceae/Urticaceae, and Arecaceae, were almost completely absent during the LGM. Furthermore, their distributions were shifted at least 750 km further north, suggesting a cooling between 3°C and 7°C and a strengthening of Antarctic cold fronts during full-glacial times. A depauperate tropical rain forest developed as part of a successional sequence after ca. 12,300 14C yr B.P. There is no evidence that Araucaria trees occurred in the Atlantic lowland during glacial times. The rain forest was disturbed by marine incursions during the early Holocene period until ca. 6100 14C yr B.P., as indicated by the presence of microforaminifera. A closed Atlantic rain forest then developed at the study site.

  2. Interactions among nitrogen fixation and soil phosphorus acquisition strategies in lowland tropical rain forests.

    PubMed

    Nasto, Megan K; Alvarez-Clare, Silvia; Lekberg, Ylva; Sullivan, Benjamin W; Townsend, Alan R; Cleveland, Cory C

    2014-10-01

    Paradoxically, symbiotic dinitrogen (N2 ) fixers are abundant in nitrogen (N)-rich, phosphorus (P)-poor lowland tropical rain forests. One hypothesis to explain this pattern states that N2 fixers have an advantage in acquiring soil P by producing more N-rich enzymes (phosphatases) that mineralise organic P than non-N2 fixers. We assessed soil and root phosphatase activity between fixers and non-fixers in two lowland tropical rain forest sites, but also addressed the hypothesis that arbuscular mycorrhizal (AM) colonisation (another P acquisition strategy) is greater on fixers than non-fixers. Root phosphatase activity and AM colonisation were higher for fixers than non-fixers, and strong correlations between AM colonisation and N2 fixation at both sites suggest that the N-P interactions mediated by fixers may generally apply across tropical forests. We suggest that phosphatase enzymes and AM fungi enhance the capacity of N2 fixers to acquire soil P, thus contributing to their high abundance in tropical forests.

  3. Impact of logging on aboveground biomass stocks in lowland rain forest, Papua New Guinea.

    PubMed

    Bryan, Jane; Shearman, Phil; Ash, Julian; Kirkpatrick, J B

    2010-12-01

    Greenhouse-gas emissions resulting from logging are poorly quantified across the tropics. There is a need for robust measurement of rain forest biomass and the impacts of logging from which carbon losses can be reliably estimated at regional and global scales. We used a modified Bitterlich plotless technique to measure aboveground live biomass at six unlogged and six logged rain forest areas (coupes) across two approximately 3000-ha regions at the Makapa concession in lowland Papua New Guinea. "Reduced-impact logging" is practiced at Makapa. We found the mean unlogged aboveground biomass in the two regions to be 192.96 +/- 4.44 Mg/ha and 252.92 +/- 7.00 Mg/ha (mean +/- SE), which was reduced by logging to 146.92 +/- 4.58 Mg/ha and 158.84 +/- 4.16, respectively. Killed biomass was not a fixed proportion, but varied with unlogged biomass, with 24% killed in the lower-biomass region, and 37% in the higher-biomass region. Across the two regions logging resulted in a mean aboveground carbon loss of 35 +/- 2.8 Mg/ha. The plotless technique proved efficient at estimating mean aboveground biomass and logging damage. We conclude that substantial bias is likely to occur within biomass estimates derived from single unreplicated plots. PMID:21265444

  4. Tree fern trunks facilitate seedling regeneration in a productive lowland temperate rain forest.

    PubMed

    Gaxiola, Aurora; Burrows, Larry E; Coomes, David A

    2008-03-01

    Seedling regeneration on forest floors is often impaired by competition with established plants. In some lowland temperate rain forests, tree fern trunks provide safe sites on which tree species establish, and grow large enough to take root in the ground and persist. Here we explore the competitive and facilitative effects of two tree fern species, Cyathea smithii and Dicksonia squarrosa, on the epiphytic regeneration of tree species in nutrient-rich alluvial forests in New Zealand. The difficulties that seedlings have in establishing on vertical tree fern trunks were indicated by the following observations. First, seedling abundance was greatest on the oldest sections of tree fern trunks, near the base, suggesting that trunks gradually recruited more and more seedlings over time, but many sections of trunk were devoid of seedlings, indicating the difficulty of establishment on a vertical surface. Second, most seedlings were from small-seeded species, presumably because smaller seeds can easily lodge on tree fern trunks. Deer browsing damage was observed on 73% of epiphytic seedlings growing within 2 m of the ground, whereas few seedlings above that height were browsed. This suggests that tree ferns provide refugia from introduced deer, and may slow the decline in population size of deer-preferred species. We reasoned that tree ferns would compete with epiphytic seedlings for light, because below the tree fern canopy photosynthetically active radiation (PAR) was about 1% of above-canopy PAR. Frond removal almost tripled %PAR on the forest floor, leading to a significant increase in the height growth rate (HGR) of seedlings planted on the forest floor, but having no effects on the HGRs of epiphytic seedlings. Our study shows evidence of direct facilitative interactions by tree ferns during seedling establishment in plant communities associated with nutrient-rich soils.

  5. Degradation of Root Community Traits as Indicator for Transformation of Tropical Lowland Rain Forests into Oil Palm and Rubber Plantations.

    PubMed

    Sahner, Josephine; Budi, Sri Wilarso; Barus, Henry; Edy, Nur; Meyer, Marike; Corre, Marife D; Polle, Andrea

    2015-01-01

    Conversion of tropical forests into intensely managed plantations is a threat to ecosystem functions. On Sumatra, Indonesia, oil palm (Elaeis guineensis) plantations are rapidly expanding, displacing rain forests and extensively used rubber (Hevea brasiliensis) agro-forests. Here, we tested the influence of land use systems on root traits including chemical traits (carbon, nitrogen, mineral nutrients, potentially toxic elements [aluminium, iron] and performance traits (root mass, vitality, mycorrhizal colonization). Traits were measured as root community-weighed traits (RCWTs) in lowland rain forests, in rubber agro-forests mixed with rain forest trees, in rubber and oil palm plantations in two landscapes (Bukit Duabelas and Harapan, Sumatra). We hypothesized that RCWTs vary with land use system indicating increasing transformation intensity and loss of ecosystem functions. The main factors found to be related to increasing transformation intensity were declining root vitality and root sulfur, nitrogen, carbon, manganese concentrations and increasing root aluminium and iron concentrations as well as increasing spore densities of arbuscular mycorrhizas. Mycorrhizal abundance was high for arbuscular and low for ectomycorrhizas and unrelated to changes in RCWTs. The decline in RCWTs showed significant correlations with soil nitrogen, soil pH and litter carbon. Thus, our study uncovered a relationship between deteriorating root community traits and loss of ecosystem functionality and showed that increasing transformation intensity resulted in decreasing root nutrition and health. Based on these results we suggest that land management that improves root vitality may enhance the ecological functions of intense tropical production systems. PMID:26366576

  6. Degradation of Root Community Traits as Indicator for Transformation of Tropical Lowland Rain Forests into Oil Palm and Rubber Plantations.

    PubMed

    Sahner, Josephine; Budi, Sri Wilarso; Barus, Henry; Edy, Nur; Meyer, Marike; Corre, Marife D; Polle, Andrea

    2015-01-01

    Conversion of tropical forests into intensely managed plantations is a threat to ecosystem functions. On Sumatra, Indonesia, oil palm (Elaeis guineensis) plantations are rapidly expanding, displacing rain forests and extensively used rubber (Hevea brasiliensis) agro-forests. Here, we tested the influence of land use systems on root traits including chemical traits (carbon, nitrogen, mineral nutrients, potentially toxic elements [aluminium, iron] and performance traits (root mass, vitality, mycorrhizal colonization). Traits were measured as root community-weighed traits (RCWTs) in lowland rain forests, in rubber agro-forests mixed with rain forest trees, in rubber and oil palm plantations in two landscapes (Bukit Duabelas and Harapan, Sumatra). We hypothesized that RCWTs vary with land use system indicating increasing transformation intensity and loss of ecosystem functions. The main factors found to be related to increasing transformation intensity were declining root vitality and root sulfur, nitrogen, carbon, manganese concentrations and increasing root aluminium and iron concentrations as well as increasing spore densities of arbuscular mycorrhizas. Mycorrhizal abundance was high for arbuscular and low for ectomycorrhizas and unrelated to changes in RCWTs. The decline in RCWTs showed significant correlations with soil nitrogen, soil pH and litter carbon. Thus, our study uncovered a relationship between deteriorating root community traits and loss of ecosystem functionality and showed that increasing transformation intensity resulted in decreasing root nutrition and health. Based on these results we suggest that land management that improves root vitality may enhance the ecological functions of intense tropical production systems.

  7. Degradation of Root Community Traits as Indicator for Transformation of Tropical Lowland Rain Forests into Oil Palm and Rubber Plantations

    PubMed Central

    Edy, Nur; Meyer, Marike; Corre, Marife D.; Polle, Andrea

    2015-01-01

    Conversion of tropical forests into intensely managed plantations is a threat to ecosystem functions. On Sumatra, Indonesia, oil palm (Elaeis guineensis) plantations are rapidly expanding, displacing rain forests and extensively used rubber (Hevea brasiliensis) agro-forests. Here, we tested the influence of land use systems on root traits including chemical traits (carbon, nitrogen, mineral nutrients, potentially toxic elements [aluminium, iron] and performance traits (root mass, vitality, mycorrhizal colonization). Traits were measured as root community-weighed traits (RCWTs) in lowland rain forests, in rubber agro-forests mixed with rain forest trees, in rubber and oil palm plantations in two landscapes (Bukit Duabelas and Harapan, Sumatra). We hypothesized that RCWTs vary with land use system indicating increasing transformation intensity and loss of ecosystem functions. The main factors found to be related to increasing transformation intensity were declining root vitality and root sulfur, nitrogen, carbon, manganese concentrations and increasing root aluminium and iron concentrations as well as increasing spore densities of arbuscular mycorrhizas. Mycorrhizal abundance was high for arbuscular and low for ectomycorrhizas and unrelated to changes in RCWTs. The decline in RCWTs showed significant correlations with soil nitrogen, soil pH and litter carbon. Thus, our study uncovered a relationship between deteriorating root community traits and loss of ecosystem functionality and showed that increasing transformation intensity resulted in decreasing root nutrition and health. Based on these results we suggest that land management that improves root vitality may enhance the ecological functions of intense tropical production systems. PMID:26366576

  8. Holocene History of the Chocó Rain Forest from Laguna Piusbi, Southern Pacific Lowlands of Colombia

    NASA Astrophysics Data System (ADS)

    Behling, Hermann; Hooghiemstra, Henry; Negret, Alvaro José

    1998-11-01

    A high-resolution pollen record from a 5-m-long sediment core from the closed-lake basin Laguna Piusbi in the southern Colombian Pacific lowlands of Chocó, dated by 11 AMS 14C dates that range from ca. 7670 to 220 14C yr B.P., represents the first Holocene record from the Chocó rain forest area. The interval between 7600 and 6100 14C yr B.P. (500-265 cm), composed of sandy clays that accumulated during the initial phase of lake formation, is almost barren of pollen. Fungal spores and the presence of herbs and disturbance taxa suggest the basin was at least temporarily inundated and the vegetation was open. The closed lake basin might have formed during an earthquake, probably about 4400 14C yr B.P. From the interval of about 6000 14C yr B.P. onwards, 200 different pollen and spore types were identified in the core, illustrating a diverse floristic composition of the local rain forest. Main taxa are Moraceae/Urticaceae, Cecropia,Melastomataceae/Combretaceae, Acalypha, Alchornea,Fabaceae, Mimosa, Piper, Protium, Sloanea, Euterpe/Geonoma, Socratea,and Wettinia.Little change took place during that time interval. Compared to the pollen records from the rain forests of the Colombian Amazon basin and adjacent savannas, the Chocó rain forest ecosystem has been very stable during the late Holocene. Paleoindians probably lived there at least since 3460 14C yr B.P. Evidence of agricultural activity, shown by cultivation of Zea maissurrounding the lake, spans the last 1710 yr. Past and present very moist climate and little human influence are important factors in maintaining the stable ecosystem and high biodiversity of the Chocó rain forest.

  9. Importance of terrestrial arthropods as subsidies in lowland Neotropical rain forest stream ecosystems

    USGS Publications Warehouse

    Small, Gaston E.; Torres, Pedro J.; Schwizer, Lauren M.; Duff, John H.; Pringle, Catherine M.

    2013-01-01

    The importance of terrestrial arthropods has been documented in temperate stream ecosystems, but little is known about the magnitude of these inputs in tropical streams. Terrestrial arthropods falling from the canopy of tropical forests may be an important subsidy to tropical stream food webs and could also represent an important flux of nitrogen (N) and phosphorus (P) in nutrient-poor headwater streams. We quantified input rates of terrestrial insects in eight streams draining lowland tropical wet forest in Costa Rica. In two focal headwater streams, we also measured capture efficiency by the fish assemblage and quantified terrestrially derived N- and P-excretion relative to stream nutrient uptake rates. Average input rates of terrestrial insects ranged from 5 to 41 mg dry mass/m2/d, exceeding previous measurements of aquatic invertebrate secondary production in these study streams, and were relatively consistent year-round, in contrast to values reported in temperate streams. Terrestrial insects accounted for half of the diet of the dominant fish species, Priapicthys annectens. Although terrestrially derived fish excretion was found to be a small flux relative to measured nutrient uptake rates in the focal streams, the efficient capture and processing of terrestrial arthropods by fish made these nutrients available to the local stream ecosystem. This aquatic-terrestrial linkage is likely being decoupled by deforestation in many tropical regions, with largely unknown but potentially important ecological consequences.

  10. Monocot Leaves are Eaten Less than Dicot Leaves in Tropical Lowland Rain Forests: Correlations with Toughness and Leaf Presentation

    PubMed Central

    Grubb, Peter J.; Jackson, Robyn V.; Barberis, Ignacio M.; Bee, Jennie N.; Coomes, David A.; Dominy, Nathaniel J.; De La Fuente, Marie Ann S.; Lucas, Peter W.; Metcalfe, Daniel J.; Svenning, Jens-Christian; Turner, Ian M.; Vargas, Orlando

    2008-01-01

    Background and Aims In tropical lowland rain forest (TLRF) the leaves of most monocots differ from those of most dicots in two ways that may reduce attack by herbivores. Firstly, they are tougher. Secondly, the immature leaves are tightly folded or rolled until 50–100 % of their final length. It was hypothesized that (a) losses of leaf area to herbivorous invertebrates are generally greatest during leaf expansion and smaller for monocots than for dicots, and (b) where losses after expansion are appreciable any difference between monocots and dicots then is smaller than that found during expansion. Methods At six sites on four continents, estimates were made of lamina area loss from the four most recently mature leaves of focal monocots and of the nearest dicot shoot. Measurements of leaf mass per unit area, and the concentrations of water and nitrogen were made for many of the species. In Panama, the losses from monocots (palms) and dicots were also measured after placing fully expanded palm leaflets and whole dicot leaves on trails of leaf-cutter ants. Key Results At five of six sites monocots experienced significantly smaller leaf area loss than dicots. The results were not explicable in terms of leaf mass per unit area, or concentrations of water or nitrogen. At only one site was the increase in loss from first to fourth mature leaf significant (also large and the same in monocots and dicots), but the losses sustained during expansion were much smaller in the monocots. In the leaf-cutter ant experiment, losses were much smaller for palms than for dicots. Conclusions The relationship between toughness and herbivory is complex; despite the negative findings of some recent authors for dicots we hypothesize that either greater toughness or late folding can protect monocot leaves against herbivorous insects in tropical lowland rain forest, and that the relative importance varies widely with species. The difficulties of establishing unequivocally the roles of leaf

  11. The genetic population structure of wild western lowland gorillas (Gorilla gorilla gorilla) living in continuous rain forest.

    PubMed

    Fünfstück, Tillmann; Arandjelovic, Mimi; Morgan, David B; Sanz, Crickette; Breuer, Thomas; Stokes, Emma J; Reed, Patricia; Olson, Sarah H; Cameron, Ken; Ondzie, Alain; Peeters, Martine; Kühl, Hjalmar S; Cipolletta, Chloe; Todd, Angelique; Masi, Shelly; Doran-Sheehy, Diane M; Bradley, Brenda J; Vigilant, Linda

    2014-09-01

    To understand the evolutionary histories and conservation potential of wild animal species it is useful to assess whether taxa are genetically structured into different populations and identify the underlying factors responsible for any clustering. Landscape features such as rivers may influence genetic population structure, and analysis of structure by sex can further reveal effects of sex-specific dispersal. Using microsatellite genotypes obtained from noninvasively collected fecal samples we investigated the population structure of 261 western lowland gorillas (WLGs) (Gorilla gorilla gorilla) from seven locations spanning an approximately 37,000 km(2) region of mainly continuous rain forest within Central African Republic (CAR), Republic of Congo and Cameroon. We found our sample to consist of two or three significantly differentiated clusters. The boundaries of the clusters coincided with courses of major rivers. Moreover, geographic distance detoured around rivers better-explained variation in genetic distance than straight line distance. Together these results suggest that major rivers in our study area play an important role in directing WLG gene flow. The number of clusters did not change when males and females were analyzed separately, indicating a lack of greater philopatry in WLG females than males at this scale.

  12. The Genetic Population Structure of Wild Western Lowland Gorillas (Gorilla gorilla gorilla) Living in Continuous Rain Forest

    PubMed Central

    FÜNFSTÜCK, TILLMANN; ARANDJELOVIC, MIMI; MORGAN, DAVID B.; SANZ, CRICKETTE; BREUER, THOMAS; STOKES, EMMA J.; REED, PATRICIA; OLSON, SARAH H.; CAMERON, KEN; ONDZIE, ALAIN; PEETERS, MARTINE; KÜHL, HJALMAR S.; CIPOLLETTA, CHLOE; TODD, ANGELIQUE; MASI, SHELLY; DORAN-SHEEHY, DIANE M.; BRADLEY, BRENDA J.; VIGILANT, LINDA

    2014-01-01

    To understand the evolutionary histories and conservation potential of wild animal species it is useful to assess whether taxa are genetically structured into different populations and identify the underlying factors responsible for any clustering. Landscape features such as rivers may influence genetic population structure, and analysis of structure by sex can further reveal effects of sex-specific dispersal. Using microsatellite genotypes obtained from noninvasively collected fecal samples we investigated the population structure of 261 western lowland gorillas (WLGs) (Gorilla gorilla gorilla) from seven locations spanning an approximately 37,000km2 region of mainly continuous rain forest within Central African Republic (CAR), Republic of Congo and Cameroon. We found our sample to consist of two or three significantly differentiated clusters. The boundaries of the clusters coincided with courses of major rivers. Moreover, geographic distance detoured around rivers better-explained variation in genetic distance than straight line distance. Together these results suggest that major rivers in our study area play an important role in directing WLG gene flow. The number of clusters did not change when males and females were analyzed separately, indicating a lack of greater philopatry in WLG females than males at this scale. PMID:24700547

  13. The influence of habitat structure on bird species composition in lowland malaysian rain forests.

    PubMed

    Mansor, Mohammad Saiful; Sah, Shahrul Anuar Mohd

    2012-05-01

    Bird surveys were conducted in the Bukit Kepala Gajah limestone area in Lenggong, Perak from July 2010 to January 2011. The study area was divided into three zones: forest edge, forest intermediate and forest interior. A point-count distance sampling method was used in the bird surveys. The study recorded 7789 detections, representing 100 bird species belonging to 28 families. Pycnonotidae, Timaliidae and Nectariniidae were the dominant families overall and showed the highest number of observations recorded in the study area whereas Motacillidae showed the fewest observations. The bird species were grouped into three feeding guilds: insectivores, frugivores and others (omnivores, carnivores, nectarivores and granivores). The species richness of insectivorous birds differed significantly among the forest zones sampled (Kruskal-Wallis: α=0.05, H=10.979, d.f.=2, p=0.004), with more insectivorous birds occurring in the forest interior. No significant differences were found among the zones in the species richness of either the frugivore guild or the composite others guild.

  14. The Influence of Habitat Structure on Bird Species Composition in Lowland Malaysian Rain Forests

    PubMed Central

    Mansor, Mohammad Saiful; Sah, Shahrul Anuar Mohd

    2012-01-01

    Bird surveys were conducted in the Bukit Kepala Gajah limestone area in Lenggong, Perak from July 2010 to January 2011. The study area was divided into three zones: forest edge, forest intermediate and forest interior. A point-count distance sampling method was used in the bird surveys. The study recorded 7789 detections, representing 100 bird species belonging to 28 families. Pycnonotidae, Timaliidae and Nectariniidae were the dominant families overall and showed the highest number of observations recorded in the study area whereas Motacillidae showed the fewest observations. The bird species were grouped into three feeding guilds: insectivores, frugivores and others (omnivores, carnivores, nectarivores and granivores). The species richness of insectivorous birds differed significantly among the forest zones sampled (Kruskal-Wallis: α=0.05, H=10.979, d.f.=2, p=0.004), with more insectivorous birds occurring in the forest interior. No significant differences were found among the zones in the species richness of either the frugivore guild or the composite others guild. PMID:24575221

  15. Testing mixing models of old and young groundwater in a tropical lowland rain forest with environmental tracers

    USGS Publications Warehouse

    Solomon, D. Kip; Genereux, David P.; Plummer, L. Niel; Busenberg, Eurybiades

    2010-01-01

    We tested three models of mixing between old interbasin groundwater flow (IGF) and young, locally derived groundwater in a lowland rain forest in Costa Rica using a large suite of environmental tracers. We focus on the young fraction of water using the transient tracers CFC-11, CFC-12, CFC-113, SF6, 3H, and bomb 14C. We measured 3He, but 3H/3He dating is generally problematic due to the presence of mantle 3He. Because of their unique concentration histories in the atmosphere, combinations of transient tracers are sensitive not only to subsurface travel times but also to mixing between waters having different travel times. Samples fall into three distinct categories: (1) young waters that plot along a piston flow line, (2) old samples that have near-zero concentrations of the transient tracers, and (3) mixtures of 1 and 2. We have modeled the concentrations of the transient tracers using (1) a binary mixing model (BMM) of old and young water with the young fraction transported via piston flow, (2) an exponential mixing model (EMM) with a distribution of groundwater travel times characterized by a mean value, and (3) an exponential mixing model for the young fraction followed by binary mixing with an old fraction (EMM/BMM). In spite of the mathematical differences in the mixing models, they all lead to a similar conceptual model of young (0 to 10 year) groundwater that is locally derived mixing with old (>1000 years) groundwater that is recharged beyond the surface water boundary of the system.

  16. Testing mixing models of old and young groundwater in a tropical lowland rain forest with environmental tracers

    NASA Astrophysics Data System (ADS)

    Solomon, D. Kip; Genereux, David P.; Plummer, L. Niel; Busenberg, Eurybiades

    2010-04-01

    We tested three models of mixing between old interbasin groundwater flow (IGF) and young, locally derived groundwater in a lowland rain forest in Costa Rica using a large suite of environmental tracers. We focus on the young fraction of water using the transient tracers CFC-11, CFC-12, CFC-113, SF6, 3H, and bomb 14C. We measured 3He, but 3H/3He dating is generally problematic due to the presence of mantle 3He. Because of their unique concentration histories in the atmosphere, combinations of transient tracers are sensitive not only to subsurface travel times but also to mixing between waters having different travel times. Samples fall into three distinct categories: (1) young waters that plot along a piston flow line, (2) old samples that have near-zero concentrations of the transient tracers, and (3) mixtures of 1 and 2. We have modeled the concentrations of the transient tracers using (1) a binary mixing model (BMM) of old and young water with the young fraction transported via piston flow, (2) an exponential mixing model (EMM) with a distribution of groundwater travel times characterized by a mean value, and (3) an exponential mixing model for the young fraction followed by binary mixing with an old fraction (EMM/BMM). In spite of the mathematical differences in the mixing models, they all lead to a similar conceptual model of young (0 to 10 year) groundwater that is locally derived mixing with old (>1000 years) groundwater that is recharged beyond the surface water boundary of the system.

  17. In Tropical Lowland Rain Forests Monocots have Tougher Leaves than Dicots, and Include a New Kind of Tough Leaf

    PubMed Central

    Dominy, Nathaniel J.; Grubb, Peter J.; Jackson, Robyn V.; Lucas, Peter W.; Metcalfe, Daniel J.; Svenning, Jens-Christian; Turner, Ian M.

    2008-01-01

    Background and Aims There has been little previous work on the toughness of the laminae of monocots in tropical lowland rain forest (TLRF) despite the potential importance of greater toughness in inhibiting herbivory by invertebrates. Of 15 monocot families with >100 species in TLRF, eight have notably high densities of fibres in the lamina so that high values for toughness are expected. Methods In north-eastern Australia punch strength was determined with a penetrometer for both immature leaves (approx. 30 % final area on average) and fully expanded, fully toughened leaves. In Singapore and Panama, fracture toughness was determined with an automated scissors apparatus using fully toughened leaves only. Key Results In Australia punch strength was, on average, 7× greater in shade-tolerant monocots than in neighbouring dicots at the immature stage, and 3× greater at the mature stage. In Singapore, shade-tolerant monocots had, on average, 1·3× higher values for fracture toughness than neighbouring dicots. In Panama, both shade-tolerant and gap-demanding monocots were tested; they did not differ in fracture toughness. The monocots had markedly higher values than the dicots whether shade-tolerant or gap-demanding species were considered. Conclusions It is predicted that monocots will be found to experience lower rates of herbivory by invertebrates than dicots. The tough monocot leaves include both stiff leaves containing relatively little water at saturation (e.g. palms), and leaves which lack stiffness, are rich in water at saturation and roll readily during dry weather or even in bright sun around midday (e.g. gingers, heliconias and marants). Monocot leaves also show that it is possible for leaves to be notably tough throughout the expansion phase of development, something never recorded for dicots. The need to broaden the botanist's mental picture of a ‘tough leaf’ is emphasized. PMID:18387969

  18. Spatial and Temporal Patterns of Throughfall Amounts and Solutes in a Tropical Montane Forest - Comparisons with Findings From Lowland Rain Forests

    NASA Astrophysics Data System (ADS)

    Zimmermann, A.

    2007-05-01

    stability patterns of solute deposition were somewhat weaker than for concentrations for most of the solutes. Epiphytes strongly affected time stability patterns in that collectors situated below thick moss mats or arboreal bromeliads were in large part responsible for the extreme persistence with low throughfall amounts and high ion concentrations (H+ showed low concentrations). Rainfall solute concentrations were low compared with a variety of other tropical lowland and montane forest sites and showed a small temporal variability during the study period for both between and within-event dynamics, respectively. Throughfall solute concentrations were more within the range when compared with other sites and showed highly variable within-event dynamics. For most of the solutes, within-event concentrations did not reach low, constant concentrations in later event stages, rather concentrations fluctuated (e.g. Cl-) or increased (e.g. K and TOC). The within-event throughfall solute concentration dynamics in this lower montane rain forest contrast to recent observations from lowland tropical rain forests in Panama and Brazil. The observed within-event patterns are attributed (1) to the influence of epiphytes and associated canopy humus, and (2) to low rainfall intensities.

  19. Ecological distribution of leaf stomata and trichomes among tree species in a Malaysian lowland tropical rain forest.

    PubMed

    Ichie, Tomoaki; Inoue, Yuta; Takahashi, Narumi; Kamiya, Koichi; Kenzo, Tanaka

    2016-07-01

    The vertical structure of a tropical rain forest is complex and multilayered, with strong variation of micro-environment with height up to the canopy. We investigated the relation between morphological traits of leaf surfaces and tree ecological characteristics in a Malaysian tropical rain forest. The shapes and densities of stomata and trichomes on the abaxial leaf surfaces and their relation with leaf characteristics such as leaf area and leaf mass per area (LMA) were studied in 136 tree species in 35 families with different growth forms in the tropical moist forest. Leaf physiological properties were also measured in 50 canopy and emergent species. Most tree species had flat type (40.4 %) or mound type (39.7 %) stomata. In addition, 84 species (61.76 %) in 22 families had trichomes, including those with glandular (17.65 %) and non-glandular trichomes (44.11 %). Most leaf characteristics significantly varied among the growth form types: species in canopy and emergent layers and canopy gap conditions had higher stomatal density, stomatal pore index (SPI), trichome density and LMA than species in understory and subcanopy layers, though the relation of phylogenetically independent contrasts to each characteristic was not statistically significant, except for leaf stomatal density, SPI and LMA. Intrinsic water use efficiency in canopy and emergent tree species with higher trichome densities was greater than in species with lower trichome densities. These results suggest that tree species in tropical rain forests adapt to a spatial difference in their growth forms, which are considerably affected by phylogenetic context, by having different stomatal and trichome shapes and/or densities.

  20. Ecological distribution of leaf stomata and trichomes among tree species in a Malaysian lowland tropical rain forest.

    PubMed

    Ichie, Tomoaki; Inoue, Yuta; Takahashi, Narumi; Kamiya, Koichi; Kenzo, Tanaka

    2016-07-01

    The vertical structure of a tropical rain forest is complex and multilayered, with strong variation of micro-environment with height up to the canopy. We investigated the relation between morphological traits of leaf surfaces and tree ecological characteristics in a Malaysian tropical rain forest. The shapes and densities of stomata and trichomes on the abaxial leaf surfaces and their relation with leaf characteristics such as leaf area and leaf mass per area (LMA) were studied in 136 tree species in 35 families with different growth forms in the tropical moist forest. Leaf physiological properties were also measured in 50 canopy and emergent species. Most tree species had flat type (40.4 %) or mound type (39.7 %) stomata. In addition, 84 species (61.76 %) in 22 families had trichomes, including those with glandular (17.65 %) and non-glandular trichomes (44.11 %). Most leaf characteristics significantly varied among the growth form types: species in canopy and emergent layers and canopy gap conditions had higher stomatal density, stomatal pore index (SPI), trichome density and LMA than species in understory and subcanopy layers, though the relation of phylogenetically independent contrasts to each characteristic was not statistically significant, except for leaf stomatal density, SPI and LMA. Intrinsic water use efficiency in canopy and emergent tree species with higher trichome densities was greater than in species with lower trichome densities. These results suggest that tree species in tropical rain forests adapt to a spatial difference in their growth forms, which are considerably affected by phylogenetic context, by having different stomatal and trichome shapes and/or densities. PMID:26879931

  1. The Children's Rain Forest.

    ERIC Educational Resources Information Center

    Thornton, Carol A.; And Others

    1995-01-01

    Describes a unit on rain forests in which first graders studied about rain forests, built a classroom rain forest, and created a bulletin board. They also graphed rainfall, estimated body water, and estimated the number of newspapers that could be produced from one canopy tree. (MKR)

  2. Rain forest preservation

    SciTech Connect

    Weiner, R.F. )

    1989-01-01

    The author discusses the possible impact the destruction of the tropical rain forest in South America has had on the atmosphere. Slash-and-burn agricultural practices have caused laterization of the soils, because rain forest vegetation carries nutrients, rather than the soil. The fact that the vegetation of the rain forest can help metabolize the excess carbon dioxide in the atmosphere is also mentioned.

  3. Life in Tropical Rain Forests.

    ERIC Educational Resources Information Center

    NatureScope, 1989

    1989-01-01

    Discusses the diversity of rain forest life, the adaptations of rain forest plants and animals, and ways these organisms interact. Includes activities on canopy critters with a copyable sheet, rain forest revue, design a plant, and jungle sleuths. (RT)

  4. Rain Forest Murals

    ERIC Educational Resources Information Center

    Kleiner, Cheryl

    2010-01-01

    The rain forest murals in the author's school began as a request from her principal to have students decorate the cafeteria with their own paintings. She decided to brainstorm ideas with her eighth-grade students. Taking into consideration the architectural space and the environmental concerns they wanted to convey, students chose the rain forest…

  5. People & Tropical Rain Forests.

    ERIC Educational Resources Information Center

    NatureScope, 1989

    1989-01-01

    Discusses ways people who live in rain forests make a living and some of the products that enrich our lives. Provides activities covering forest people, tropical treats, jungle in the pantry, treetop explorers, and three copyable pages to accompany activities. (Author/RT)

  6. Rain Forests: Tropical Treasures.

    ERIC Educational Resources Information Center

    Braus, Judy, Ed.

    1989-01-01

    Ranger Rick's NatureScope is a creative education series dedicated to inspiring in children an understanding and appreciation of the natural world while developing the skills they will need to make responsible decisions about the environment. The topic of this issue is "Rain Forests: Tropical Treasures." Contents are organized into the following…

  7. Lessons from the Rain Forest.

    ERIC Educational Resources Information Center

    Phillips, Shelley

    2002-01-01

    Presents a first-grade art project after students learned about the rain forest and heard the story, "The Great Kapok Tree: A Tale of the Amazon Rain Forest" (Lynn Cherry). Explains that the students created pictures of the rain forest. (CMK)

  8. A long pollen record from lowland Amazonia: Forest and cooling in glacial times

    SciTech Connect

    Colinvaux, P.A.; Moreno, J.E.; Bush, M.B.

    1996-10-04

    A continuous pollen history of more than 40,000 years was obtained from a lake in the lowland Amazon rain forest. Pollen spectra demonstrate that tropical rain forest occupied the region continuously and that savannas or grasslands were not present during the last glacial maximum. The data suggest that the western Amazon forest was not fragmented into refugia in glacial times and that the lowlands were not a source of dust. Glacial age forests were comparable to modern forests but also included species now restricted to higher evaluations by temperature, suggesting a cooling of the order of 5{degrees} to 6{degrees}C. 23 refs., 22 tabs.

  9. Seven Guideposts for Tropical Rain Forest Education.

    ERIC Educational Resources Information Center

    Rillero, Peter

    1999-01-01

    Identifies seven guideposts for tropical rain forest education. Aids teachers in finding structure and creating educational experiences that promote more complete understanding of tropical rain forests. (CCM)

  10. An analysis of modern pollen rain from the Maya lowlands of northern Belize

    USGS Publications Warehouse

    Bhattacharya, T.; Beach, T.; Wahl, D.

    2011-01-01

    In the lowland Maya area, pollen records provide important insights into the impact of past human populations and climate change on tropical ecosystems. Despite a long history of regional paleoecological research, few studies have characterized the palynological signatures of lowland ecosystems, a fact which lowers confidence in ecological inferences made from palynological data. We sought to verify whether we could use pollen spectra to reliably distinguish modern ecosystem types in the Maya lowlands of Central America. We collected 23 soil and sediment samples from eight ecosystem types, including upland, riparian, secondary, and swamp (bajo) forests; pine savanna; and three distinct wetland communities. We analyzed pollen spectra with non-metric multidimensional scaling (NMDS), and found significant compositional differences in ecosystem types' pollen spectra. Forested sites had spectra dominated by Moraceae/Urticaceae pollen, while non-forested sites had significant portions of Poaceae, Asteraceae, and Amaranthaceae pollen. Upland, bajo, and riparian forest differed in representation of Cyperaceae, Bactris-type, and Combretaceae/Melastomataceae pollen. High percentages of pine (Pinus), oak (Quercus), and the presence of Byrsonima characterized pine savanna. Despite its limited sample size, this study provides one of the first statistical analyses of modern pollen rain in the Maya lowlands. Our results show that pollen assemblages can accurately reflect differences between ecosystem types, which may help refine interpretations of pollen records from the Maya area. ?? 2010 Elsevier B.V.

  11. A Walk in the Rain Forest.

    ERIC Educational Resources Information Center

    Gustafson, Glenn

    2001-01-01

    Presents a learning project in which students prepare a guided, multisensory rain forest tour representing its ecology. Develops five stop points presenting a theme or an important aspect of the rain forest. Includes a list of selected resources for rain forest studies. (YDS)

  12. Create a Rain Forest in the Gym.

    ERIC Educational Resources Information Center

    Kane, Karen

    1995-01-01

    Describes a creative interdisciplinary program for K-3 students that involves setting up a rain forest in the gymnasium to teach students gymnastic skills in the context of the Amazon rain forest. The paper describes how to set up the rain forest and teach a variety of classes. Rainforest resources are included. (SM)

  13. Environmental Education about the Rain Forest.

    ERIC Educational Resources Information Center

    Berkmuller, Klaus

    Designed to help in the development of an educational program about the value of rain forests, this handbook presents a condensation of issues, facts, and concepts. The handbook is divided into three parts. Part one introduces the rain forest ecosystem and provides conceptual background material needed in the determination of problems, the…

  14. Mercury in rain and throughfall in a tropical rain forest

    SciTech Connect

    Lindberg, S.E.; Harriss, R.C.

    1985-01-01

    The major hydrologic pathways from the atmosphere to the ground in a tropical rain forest were sampled to determine the wet deposition of mercury above and below the canopy. The concentrations of mercury in rain averaged 74 ng L/sup -1/ and were inversely proportional to rainfall amount. Concentrations in stemflow and throughfall were comparable, averaging approx.66 ng L/sup -1/. As a result of these lower concentrations and significant rainfall interception and evaporation in the canopy, the total wet fluxes below the canopy were lower than those above, suggesting in-canopy sorption of dissolved mercury. 7 refs., 1 fig., 2 tabs.

  15. Soil phosphorus and the ecology of lowland tropical forests

    NASA Astrophysics Data System (ADS)

    Turner, Ben

    2016-04-01

    In this presentation I will explore the extent to which phosphorus influences the productivity, diversity, and distribution of plant species in tropical forests. I will highlight the range of soils that occur in tropical forests and will argue that pedogenesis and associated phosphorus depletion is a primary driver of forest diversity over long timescales. I will draw on data from a regional-scale network of forest dynamics plots in Panama to show that tree species distributions are determined predominantly as a function of dry season intensity and soil phosphorus availability, and will suggest potential mechanistic explanations for this pattern in relation to phosphorus acquisition. Finally, I will present observational and experimental evidence from Panama to show how phosphorus, nitrogen, and potassium, limit plant productivity and microbial communities on strongly-weathered soils in the lowland tropics.

  16. Thermokarst rates intensify due to climate change and forest fragmentation in an Alaskan boreal forest lowland.

    PubMed

    Lara, Mark J; Genet, Hélène; McGuire, Anthony D; Euskirchen, Eugénie S; Zhang, Yujin; Brown, Dana R N; Jorgenson, Mark T; Romanovsky, Vladimir; Breen, Amy; Bolton, William R

    2016-02-01

    Lowland boreal forest ecosystems in Alaska are dominated by wetlands comprised of a complex mosaic of fens, collapse-scar bogs, low shrub/scrub, and forests growing on elevated ice-rich permafrost soils. Thermokarst has affected the lowlands of the Tanana Flats in central Alaska for centuries, as thawing permafrost collapses forests that transition to wetlands. Located within the discontinuous permafrost zone, this region has significantly warmed over the past half-century, and much of these carbon-rich permafrost soils are now within ~0.5 °C of thawing. Increased permafrost thaw in lowland boreal forests in response to warming may have consequences for the climate system. This study evaluates the trajectories and potential drivers of 60 years of forest change in a landscape subjected to permafrost thaw in unburned dominant forest types (paper birch and black spruce) associated with location on elevated permafrost plateau and across multiple time periods (1949, 1978, 1986, 1998, and 2009) using historical and contemporary aerial and satellite images for change detection. We developed (i) a deterministic statistical model to evaluate the potential climatic controls on forest change using gradient boosting and regression tree analysis, and (ii) a 30 × 30 m land cover map of the Tanana Flats to estimate the potential landscape-level losses of forest area due to thermokarst from 1949 to 2009. Over the 60-year period, we observed a nonlinear loss of birch forests and a relatively continuous gain of spruce forest associated with thermokarst and forest succession, while gradient boosting/regression tree models identify precipitation and forest fragmentation as the primary factors controlling birch and spruce forest change, respectively. Between 1950 and 2009, landscape-level analysis estimates a transition of ~15 km² or ~7% of birch forests to wetlands, where the greatest change followed warm periods. This work highlights that the vulnerability and resilience of

  17. Thermokarst rates intensify due to climate change and forest fragmentation in an Alaskan boreal forest lowland.

    PubMed

    Lara, Mark J; Genet, Hélène; McGuire, Anthony D; Euskirchen, Eugénie S; Zhang, Yujin; Brown, Dana R N; Jorgenson, Mark T; Romanovsky, Vladimir; Breen, Amy; Bolton, William R

    2016-02-01

    Lowland boreal forest ecosystems in Alaska are dominated by wetlands comprised of a complex mosaic of fens, collapse-scar bogs, low shrub/scrub, and forests growing on elevated ice-rich permafrost soils. Thermokarst has affected the lowlands of the Tanana Flats in central Alaska for centuries, as thawing permafrost collapses forests that transition to wetlands. Located within the discontinuous permafrost zone, this region has significantly warmed over the past half-century, and much of these carbon-rich permafrost soils are now within ~0.5 °C of thawing. Increased permafrost thaw in lowland boreal forests in response to warming may have consequences for the climate system. This study evaluates the trajectories and potential drivers of 60 years of forest change in a landscape subjected to permafrost thaw in unburned dominant forest types (paper birch and black spruce) associated with location on elevated permafrost plateau and across multiple time periods (1949, 1978, 1986, 1998, and 2009) using historical and contemporary aerial and satellite images for change detection. We developed (i) a deterministic statistical model to evaluate the potential climatic controls on forest change using gradient boosting and regression tree analysis, and (ii) a 30 × 30 m land cover map of the Tanana Flats to estimate the potential landscape-level losses of forest area due to thermokarst from 1949 to 2009. Over the 60-year period, we observed a nonlinear loss of birch forests and a relatively continuous gain of spruce forest associated with thermokarst and forest succession, while gradient boosting/regression tree models identify precipitation and forest fragmentation as the primary factors controlling birch and spruce forest change, respectively. Between 1950 and 2009, landscape-level analysis estimates a transition of ~15 km² or ~7% of birch forests to wetlands, where the greatest change followed warm periods. This work highlights that the vulnerability and resilience of

  18. Rain Forests: Do They Hold Up the Sky?

    ERIC Educational Resources Information Center

    Shaw, Donna Gail; Dybdahl, Claudia S.

    1992-01-01

    This paper uses the topic of rain forests to demonstrate how a meaningful and relevant Science, Technology, and Society program can be designed for intermediate-level students. Students create and immerse themselves in a tropical rain forest, explore the forest ecosystem and peoples, and consider solutions to the problem of deforestation. (JDD)

  19. Thermokarst Rates Intensify Due to Climate Change and Forest Fragmentation in an Alaskan Boreal Forest Lowland

    NASA Astrophysics Data System (ADS)

    Lara, M. J.; Genet, H.; McGuire, A. D.; Euskirchen, E. S.; Zhang, Y.; Brown, D. N.; Jorgenson, T.; Romanovsky, V. E.; Breen, A. L.; Bolton, W. R.

    2015-12-01

    Lowland boreal forest ecosystems in Alaska are dominated by wetlands comprised of a complex mosaic of fens, collapse scar-bogs, low shrub/scrub, and forests growing on elevated ice rich permafrost soils. Thermokarst has affected the lowlands of the Tanana Flats in central Alaska for centuries, as thawing permafrost collapses forests that transition to wetlands. Located within the discontinuous permafrost zone, this region has significantly warmed over the past half-century, and much of these carbon-rich permafrost soils are now within ~0.5o C of thawing. Increases in the collapse of lowland boreal forests in response to warming may have consequences for the climate system. This study evaluates the trajectories and potential drivers of 60 years of forest change in a landscape subjected to permafrost thaw in unburned dominant forest types (paper birch and black spruce) associated with location on elevated permafrost plateau and across multiple time periods (1949, 1978, 1986, 1998 and 2009) using historical and contemporary aerial and satellite images for change detection. We developed (i) a deterministic statistical model to evaluate the potential climatic controls on forest change using gradient boosting and regression tree analysis, and (ii) a 30x30 m land cover map of the Tanana Flats to estimate the potential landscape-level losses of forest area due to thermokarst from 1949 to 2009. Over the 60-year period, we observed a nonlinear loss of birch forests and a relatively continuous gain of spruce forest associated with thermokarst and forest succession, respectively. Gradient boosting and regression tree models identify precipitation and forest fragmentation as the primary factors controlling birch and spruce forest change, respectively. Between 1950-2009 landscape-level analysis estimates a transition of ~15 km² of birch forest area to wetlands on the Tanana Flats, where the greatest change followed warm periods. This work highlights the vulnerability of lowland

  20. Monitoring Fires in Southwestern Amazonia Rain Forests

    NASA Astrophysics Data System (ADS)

    Brown, I. Foster; Schroeder, Wilfrid; Setzer, Alberto; de Los Rios Maldonado, Monica; Pantoja, Nara; Duarte, Alejandro; Marengo, Jose

    2006-06-01

    From mid-July to mid-October 2005, an environmental disaster unfolded in the trinational region of Madre de Dios, Peru; Acre, Brazil; and Pando, Bolivia (the MAP region), in southwestern Amazonia. A prolonged dry season and human-initiated fires resulted in smoke pollution affecting more than 400,000 persons, fire damage to over 300,000 hectares of rain forest, and over US$50 million of direct economic losses. Indicators suggest that anomalous drought conditions could occur again this year.

  1. Quaternary forest associations in lowland tropical West Africa

    NASA Astrophysics Data System (ADS)

    Miller, Charlotte S.; Gosling, William D.

    2014-01-01

    Terrestrial fossil pollen records are frequently used to reveal the response of vegetation to changes in both regional and global climate. Here we present a fossil pollen record from sediment cores extracted from Lake Bosumtwi (West Africa). This record covers the last c. 520 thousand years (ka) and represents the longest terrestrial pollen record from Africa published to date. The fossil pollen assemblages reveal dynamic vegetation change which can be broadly characterized as indicative of shifts between savannah and forest. Savannah formations are heavily dominated by grass (Poaceae) pollen (>55%) typically associated with Cyperaceae, Chenopodiaceae-Amaranthaceae and Caryophyllaceae. Forest formations are palynologically more diverse than the savannah, with the key taxa occurring in multiple forest zones being Moraceae, Celtis, Uapaca, Macaranga and Trema. The fossil pollen data indicate that over the last c. 520 ka the vegetation of lowland tropical West Africa has mainly been savannah; however six periods of forest expansion are evident which most likely correspond to global interglacial periods. A comparison of the forest assemblage composition within each interglacial suggests that the Holocene (11-0 ka) forest occurred under the wettest climate, while the forest which occurred at the time of Marine Isotope Stage 7 probably occurred under the driest climate.

  2. Lowland forest loss in protected areas of Indonesian Borneo.

    PubMed

    Curran, L M; Trigg, S N; McDonald, A K; Astiani, D; Hardiono, Y M; Siregar, P; Caniago, I; Kasischke, E

    2004-02-13

    The ecology of Bornean rainforests is driven by El Niño-induced droughts that trigger synchronous fruiting among trees and bursts of faunal reproduction that sustain vertebrate populations. However, many of these species- and carbon-rich ecosystems have been destroyed by logging and conversion, which increasingly threaten protected areas. Our satellite, Geographic Information System, and field-based analyses show that from 1985 to 2001, Kalimantan's protected lowland forests declined by more than 56% (>29,000 square kilometers). Even uninhabited frontier parks are logged to supply international markets. "Protected" forests have become increasingly isolated and deforested and their buffer zones degraded. Preserving the ecological integrity of Kalimantan's rainforests requires immediate transnational management. PMID:14963327

  3. Relationships among net primary productivity, nutrients and climate in tropical rain forest: A pan-tropical analysis

    USGS Publications Warehouse

    Cleveland, Cory C.; Townsend, Alan R.; Taylor, Philip; Alvarez-Clare, Silvia; Bustamante, Mercedes M.C.; Chuyong, George; Dobrowski, Solomon Z.; Grierson, Pauline; Harms, Kyle E.; Houlton, Benjamin Z.; Marklein, Alison; Parton, William; Porder, Stephen; Reed, Sasha C.; Sierra, Carlos A.; Silver, Whendee L.; Tanner, Edmund V.J.; Wieder, William R.

    2011-01-01

    Tropical rain forests play a dominant role in global biosphere-atmosphere CO2 exchange. Although climate and nutrient availability regulate net primary production (NPP) and decomposition in all terrestrial ecosystems, the nature and extent of such controls in tropical forests remain poorly resolved. We conducted a meta-analysis of carbon-nutrient-climate relationships in 113 sites across the tropical forest biome. Our analyses showed that mean annual temperature was the strongest predictor of aboveground NPP (ANPP) across all tropical forests, but this relationship was driven by distinct temperature differences between upland and lowland forests. Within lowland forests (< 1000 m), a regression tree analysis revealed that foliar and soil-based measurements of phosphorus (P) were the only variables that explained a significant proportion of the variation in ANPP, although the relationships were weak. However, foliar P, foliar nitrogen (N), litter decomposition rate (k), soil N and soil respiration were all directly related with total surface (0–10 cm) soil P concentrations. Our analysis provides some evidence that P availability regulates NPP and other ecosystem processes in lowland tropical forests, but more importantly, underscores the need for a series of large-scale nutrient manipulations – especially in lowland forests – to elucidate the most important nutrient interactions and controls.

  4. Relationships among net primary productivity, nutrients and climate in tropical rain forest: a pan-tropical analysis.

    PubMed

    Cleveland, Cory C; Townsend, Alan R; Taylor, Philip; Alvarez-Clare, Silvia; Bustamante, Mercedes M C; Chuyong, George; Dobrowski, Solomon Z; Grierson, Pauline; Harms, Kyle E; Houlton, Benjamin Z; Marklein, Alison; Parton, William; Porder, Stephen; Reed, Sasha C; Sierra, Carlos A; Silver, Whendee L; Tanner, Edmund V J; Wieder, William R

    2011-09-01

    Tropical rain forests play a dominant role in global biosphere-atmosphere CO(2) exchange. Although climate and nutrient availability regulate net primary production (NPP) and decomposition in all terrestrial ecosystems, the nature and extent of such controls in tropical forests remain poorly resolved. We conducted a meta-analysis of carbon-nutrient-climate relationships in 113 sites across the tropical forest biome. Our analyses showed that mean annual temperature was the strongest predictor of aboveground NPP (ANPP) across all tropical forests, but this relationship was driven by distinct temperature differences between upland and lowland forests. Within lowland forests (< 1000 m), a regression tree analysis revealed that foliar and soil-based measurements of phosphorus (P) were the only variables that explained a significant proportion of the variation in ANPP, although the relationships were weak. However, foliar P, foliar nitrogen (N), litter decomposition rate (k), soil N and soil respiration were all directly related with total surface (0-10 cm) soil P concentrations. Our analysis provides some evidence that P availability regulates NPP and other ecosystem processes in lowland tropical forests, but more importantly, underscores the need for a series of large-scale nutrient manipulations - especially in lowland forests - to elucidate the most important nutrient interactions and controls.

  5. Branchfall dominates annual carbon flux across lowland Amazonian forests

    NASA Astrophysics Data System (ADS)

    Marvin, David C.; Asner, Gregory P.

    2016-09-01

    Tropical forests play an important role in the global carbon cycle, but knowledge of interannual variation in the total tropical carbon flux and constituent carbon pools is highly uncertain. One such pool, branchfall, is an ecologically important dynamic with links to nutrient cycling, forest productivity, and drought. Identifying and quantifying branchfall over large areas would reveal the role of branchfall in carbon and nutrient cycling. Using data from repeat airborne light detection and ranging campaigns across a wide array of lowland Amazonian forest landscapes totaling nearly 100 000 ha, we find that upper canopy gaps—driven by branchfall—are pervasive features of every landscape studied, and are seven times more frequent than full tree mortality. Moreover, branchfall comprises a major carbon source on a landscape basis, exceeding that of tree mortality by 21%. On a per hectare basis, branchfall and tree mortality result in 0.65 and 0.72 Mg C ha-1 yr-1 gross source of carbon to the atmosphere, respectively. Reducing uncertainties in annual gross rates of tropical forest carbon flux, for example by incorporating large-scale branchfall dynamics, is crucial for effective policies that foster conservation and restoration of tropical forests. Additionally, large-scale branchfall mapping offers ecologists a new dimension of disturbance monitoring and potential new insights into ecosystem structure and function.

  6. Invasive plants transform the three-dimensional structure of rain forests

    PubMed Central

    Asner, Gregory P.; Hughes, R. Flint; Vitousek, Peter M.; Knapp, David E.; Kennedy-Bowdoin, Ty; Boardman, Joseph; Martin, Roberta E.; Eastwood, Michael; Green, Robert O.

    2008-01-01

    Biological invasions contribute to global environmental change, but the dynamics and consequences of most invasions are difficult to assess at regional scales. We deployed an airborne remote sensing system that mapped the location and impacts of five highly invasive plant species across 221,875 ha of Hawaiian ecosystems, identifying four distinct ways that these species transform the three-dimensional (3D) structure of native rain forests. In lowland to montane forests, three invasive tree species replace native midcanopy and understory plants, whereas one understory invader excludes native species at the ground level. A fifth invasive nitrogen-fixing tree, in combination with a midcanopy alien tree, replaces native plants at all canopy levels in lowland forests. We conclude that this diverse array of alien plant species, each representing a different growth form or functional type, is changing the fundamental 3D structure of native Hawaiian rain forests. Our work also demonstrates how an airborne mapping strategy can identify and track the spread of certain invasive plant species, determine ecological consequences of their proliferation, and provide detailed geographic information to conservation and management efforts. PMID:18316720

  7. Thermokarst rates intensify due to climate change and forest fragmentation in an Alaskan boreal forest lowland

    USGS Publications Warehouse

    Lara, M.; Genet, Helene; McGuire, Anthony; Euskirchen, Eugénie S.; Zhang, Yujin; Brown, Dana R. N.; Jorgenson, M.T.; Romanovsky, V.; Breen, Amy L.; Bolton, W.R.

    2016-01-01

    Lowland boreal forest ecosystems in Alaska are dominated by wetlands comprised of a complex mosaic of fens, collapse-scar bogs, low shrub/scrub, and forests growing on elevated ice-rich permafrost soils. Thermokarst has affected the lowlands of the Tanana Flats in central Alaska for centuries, as thawing permafrost collapses forests that transition to wetlands. Located within the discontinuous permafrost zone, this region has significantly warmed over the past half-century, and much of these carbon-rich permafrost soils are now within ~0.5 °C of thawing. Increased permafrost thaw in lowland boreal forests in response to warming may have consequences for the climate system. This study evaluates the trajectories and potential drivers of 60 years of forest change in a landscape subjected to permafrost thaw in unburned dominant forest types (paper birch and black spruce) associated with location on elevated permafrost plateau and across multiple time periods (1949, 1978, 1986, 1998, and 2009) using historical and contemporary aerial and satellite images for change detection. We developed (i) a deterministic statistical model to evaluate the potential climatic controls on forest change using gradient boosting and regression tree analysis, and (ii) a 30 × 30 m land cover map of the Tanana Flats to estimate the potential landscape-level losses of forest area due to thermokarst from 1949 to 2009. Over the 60-year period, we observed a nonlinear loss of birch forests and a relatively continuous gain of spruce forest associated with thermokarst and forest succession, while gradient boosting/regression tree models identify precipitation and forest fragmentation as the primary factors controlling birch and spruce forest change, respectively. Between 1950 and 2009, landscape-level analysis estimates a transition of ~15 km² or ~7% of birch forests to wetlands, where the greatest change followed warm periods. This work highlights that the vulnerability and resilience of

  8. Humid tropical rain forest has expanded into eucalypt forest and savanna over the last 50 years

    PubMed Central

    Tng, David Y P; Murphy, Brett P; Weber, Ellen; Sanders, Gregor; Williamson, Grant J; Kemp, Jeanette; Bowman, David M J S

    2012-01-01

    Tropical rain forest expansion and savanna woody vegetation thickening appear to be a global trend, but there remains uncertainty about whether there is a common set of global drivers. Using geographic information techniques, we analyzed aerial photography of five areas in the humid tropics of northeastern Queensland, Australia, taken in the 1950s and 2008, to determine if changes in rain forest extent match those reported for the Australian monsoon tropics using similar techniques. Mapping of the 1950s aerial photography showed that of the combined study area (64,430 ha), 63% was classified as eucalypt forests/woodland and 37% as rain forest. Our mapping revealed that although most boundaries remained stable, there was a net increase of 732 ha of the original rain forest area over the study period, and negligible conversion of rain forest to eucalypt forest/woodland. Statistical modeling, controlling for spatial autocorrelation, indicated distance from preexisting rain forest as the strongest determinant of rain forest expansion. Margin extension had a mean rate across the five sites of 0.6 m per decade. Expansion was greater in tall open forest types but also occurred in shorter, more flammable woodland vegetation types. No correlations were detected with other local variables (aspect, elevation, geology, topography, drainage). Using a geographically weighted mean rate of rain forest margin extension across the whole region, we predict that over 25% of tall open forest (a forest type of high conservation significance) would still remain after 2000 years of rain forest expansion. This slow replacement is due to the convoluted nature of the rain forest boundary and the irregular shape of the tall open forest patches. Our analyses point to the increased concentration of atmospheric CO2 as the most likely global driver of indiscriminate rain forest expansion occurring in northeastern Australia, by increasing tree growth and thereby overriding the effects of fire

  9. Humid tropical rain forest has expanded into eucalypt forest and savanna over the last 50 years.

    PubMed

    Tng, David Y P; Murphy, Brett P; Weber, Ellen; Sanders, Gregor; Williamson, Grant J; Kemp, Jeanette; Bowman, David M J S

    2012-01-01

    Tropical rain forest expansion and savanna woody vegetation thickening appear to be a global trend, but there remains uncertainty about whether there is a common set of global drivers. Using geographic information techniques, we analyzed aerial photography of five areas in the humid tropics of northeastern Queensland, Australia, taken in the 1950s and 2008, to determine if changes in rain forest extent match those reported for the Australian monsoon tropics using similar techniques. Mapping of the 1950s aerial photography showed that of the combined study area (64,430 ha), 63% was classified as eucalypt forests/woodland and 37% as rain forest. Our mapping revealed that although most boundaries remained stable, there was a net increase of 732 ha of the original rain forest area over the study period, and negligible conversion of rain forest to eucalypt forest/woodland. Statistical modeling, controlling for spatial autocorrelation, indicated distance from preexisting rain forest as the strongest determinant of rain forest expansion. Margin extension had a mean rate across the five sites of 0.6 m per decade. Expansion was greater in tall open forest types but also occurred in shorter, more flammable woodland vegetation types. No correlations were detected with other local variables (aspect, elevation, geology, topography, drainage). Using a geographically weighted mean rate of rain forest margin extension across the whole region, we predict that over 25% of tall open forest (a forest type of high conservation significance) would still remain after 2000 years of rain forest expansion. This slow replacement is due to the convoluted nature of the rain forest boundary and the irregular shape of the tall open forest patches. Our analyses point to the increased concentration of atmospheric CO(2) as the most likely global driver of indiscriminate rain forest expansion occurring in northeastern Australia, by increasing tree growth and thereby overriding the effects of fire

  10. Plant mineral concentrations related to foraging preferences of western lowland gorilla in Central African forest clearings.

    PubMed

    Metsio Sienne, Julia; Buchwald, Rainer; Wittemyer, George

    2014-12-01

    In the Central African rain forest, mineral resources essential to organisms are distributed heterogeneously. Forest clearings, locally known as bais, attract numerous species presumably due to the mineral richness of these sites, though understanding of the factors drawing species to bais remains speculative. Western lowland gorillas (Gorilla g. gorilla) selectively feed on particular plant species and parts within bais, but studies of such feeding preferences have focused on one site. Here, we compared concentrations of minerals and macronutrients from plants gorillas consumed and those they did not in 16 bais to gain inference regarding drivers of resource selection within bais and bai use. The availability of gorilla feeding plants varied between surveyed bais, with some consumed species occurring only at a few bais. Regardless of bai specific species composition, significantly higher concentrations of Na, K, and Ca were found in consumed plants, and other trace minerals were more common in consumed plants. In contrast, macronutrients appeared to play no major role in feeding plant selectivity with consumed species often having lower concentrations than non-consumed species. We found evidence for seasonal differences in Mg and Na concentrations, but the concentrations of other minerals in consumed plants were consistent across time. These findings provide insight to the drivers of bai visitation by gorillas. The high variation in species across bais may elicit use of multiple bais, but the general increased mineral composition of consumed species across bais suggests metabolic requirements may be met through consumption of a variety of species.

  11. Plant mineral concentrations related to foraging preferences of western lowland gorilla in Central African forest clearings.

    PubMed

    Metsio Sienne, Julia; Buchwald, Rainer; Wittemyer, George

    2014-12-01

    In the Central African rain forest, mineral resources essential to organisms are distributed heterogeneously. Forest clearings, locally known as bais, attract numerous species presumably due to the mineral richness of these sites, though understanding of the factors drawing species to bais remains speculative. Western lowland gorillas (Gorilla g. gorilla) selectively feed on particular plant species and parts within bais, but studies of such feeding preferences have focused on one site. Here, we compared concentrations of minerals and macronutrients from plants gorillas consumed and those they did not in 16 bais to gain inference regarding drivers of resource selection within bais and bai use. The availability of gorilla feeding plants varied between surveyed bais, with some consumed species occurring only at a few bais. Regardless of bai specific species composition, significantly higher concentrations of Na, K, and Ca were found in consumed plants, and other trace minerals were more common in consumed plants. In contrast, macronutrients appeared to play no major role in feeding plant selectivity with consumed species often having lower concentrations than non-consumed species. We found evidence for seasonal differences in Mg and Na concentrations, but the concentrations of other minerals in consumed plants were consistent across time. These findings provide insight to the drivers of bai visitation by gorillas. The high variation in species across bais may elicit use of multiple bais, but the general increased mineral composition of consumed species across bais suggests metabolic requirements may be met through consumption of a variety of species. PMID:24865332

  12. Relationships among precipitation regime, nutrient availability, and carbon turnover in tropical rain forests.

    PubMed

    Posada, Juan M; Schuur, Edward A G

    2011-03-01

    The effect of high precipitation regime in tropical forests is poorly known despite indications of its potentially negative effects on nutrient availability and carbon (C) cycling. Our goal was to determine if there was an effect of high rainfall on nitrogen (N) and phosphorous (P) availability and indexes of C cycling in lowland tropical rain forests exposed to a broad range of mean annual precipitation (MAP). We predicted that C turnover time would increase with MAP while the availability of N and P would decrease. We studied seven Neotropical lowland forests covering a MAP range between 2,700 and 9,500 mm. We used radiocarbon (∆(14)C) from the atmosphere and respired from soil organic matter to estimate residence time of C in plants and soils. We also used C, N, and P concentrations and the stable isotope ratio of N (δ(15)N) in live and dead plant tissues and in soils as proxies for nutrient availability. Negative δ(15)N values indicated that the wettest forests had N cycles that did not exhibit isotope-fractionating losses and were potentially N-limited. Element ratios (N:P and C:P) in senescent leaves, litter, and live roots showed that P resorption increased considerably with MAP, which points towards increasing P-limitation under high MAP regimes. Soil C content increased with MAP but C turnover time only showed a weak relationship with MAP, probably due to variations in soil parent material and age along the MAP gradient. In contrast, comparing C turnover directly to nutrient availability showed strong relationships between C turnover time, N availability (δ(15)N), and P availability (N:P) in senescent leaves and litter. Thus, an effect of MAP on carbon cycling appeared to be indirectly mediated by nutrient availability. Our results suggest that soil nutrient availability plays a central role in the dynamic of C cycling in tropical rain forests.

  13. Can lowland dry forests represent a refuge from avian malaria for native Hawaiian birds?

    USGS Publications Warehouse

    Tucker-Mohl, Katherine; Hart, Patrick; Atkinson, Carter T.

    2010-01-01

    Hawaii's native birds have become increasingly threatened over the past century. Introduced mosquito borne diseases such as avian malaria may be responsible for the near absence of endemic Hawaiian forest birds in low-elevation habitats. The recent recognition that some native Hawaiian forest birds may be repopulating moist lowland habitats as a result of evolved resistance to this disease has increased the conservation value of these areas. Here, we investigate whether remnant low elevation dry forests on Hawaii Island provide natural 'refuges' from mosquito-transmitted malaria by nature of their low rainfall and absence of suitable natural sources of water for mosquito breeding. Unlike lowland wet forests where high rates of disease transmission may be selecting for disease resistance, lowland dry forests may provide some refuge for native forest birds without natural resistance to malaria. We mistnetted forest birds in two lowland dry forests and tested all native birds by microscopy and serology for avian malaria caused by the Plasmodium relictum parasite. We also conducted surveys for standing water and mosquito larvae. Overall prevalence of infections with Plasmodium relictum in the Hawaii Amakihi Hemignathus virens virens was 15%. Most infected birds had lowlevel parasitemias, suggesting chronic infections. Although avian malaria is present in these lowland dry forest Amakihi populations, infection rates are significantly lower than in wet forest populations at similar elevations. Sources of breeding mosquitoes in these forests appeared to be largely anthropogenic; thus, there is potential to manage dry forests as mosquito-free habitat for Hawaii Amakihi and other Hawaiian forest birds.

  14. Phylogeography of the genus Podococcus (Palmae/Arecaceae) in Central African rain forests: Climate stability predicts unique genetic diversity.

    PubMed

    Faye, A; Deblauwe, V; Mariac, C; Richard, D; Sonké, B; Vigouroux, Y; Couvreur, T L P

    2016-12-01

    The tropical rain forests of Central Africa contain high levels of species diversity. Paleovegetation or biodiversity patterns suggested successive contraction/expansion phases on this rain forest cover during the last glacial maximum (LGM). Consequently, the hypothesis of the existence of refugia e.g. habitat stability that harbored populations during adverse climatic periods has been proposed. Understory species are tightly associated to forest cover and consequently are ideal markers of forest dynamics. Here, we used two central African rain forest understory species of the palm genus, Podococcus, to assess the role of past climate variation on their distribution and genetic diversity. Species distribution modeling in the present and at the LGM was used to estimate areas of climatic stability. Genetic diversity and phylogeography were estimated by sequencing near complete plastomes for over 120 individuals. Areas of climatic stability were mainly located in mountainous areas like the Monts de Cristal and Monts Doudou in Gabon, but also lowland coastal forests in southeast Cameroon and northeast Gabon. Genetic diversity analyses shows a clear North-South structure of genetic diversity within one species. This divide was estimated to have originated some 500,000years ago. We show that, in Central Africa, high and unique genetic diversity is strongly correlated with inferred areas of climatic stability since the LGM. Our results further highlight the importance of coastal lowland rain forests in Central Africa as harboring not only high species diversity but also important high levels of unique genetic diversity. In the context of strong human pressure on coastal land use and destruction, such unique diversity hotspots need to be considered in future conservation planning. PMID:27521478

  15. Phylogeography of the genus Podococcus (Palmae/Arecaceae) in Central African rain forests: Climate stability predicts unique genetic diversity.

    PubMed

    Faye, A; Deblauwe, V; Mariac, C; Richard, D; Sonké, B; Vigouroux, Y; Couvreur, T L P

    2016-12-01

    The tropical rain forests of Central Africa contain high levels of species diversity. Paleovegetation or biodiversity patterns suggested successive contraction/expansion phases on this rain forest cover during the last glacial maximum (LGM). Consequently, the hypothesis of the existence of refugia e.g. habitat stability that harbored populations during adverse climatic periods has been proposed. Understory species are tightly associated to forest cover and consequently are ideal markers of forest dynamics. Here, we used two central African rain forest understory species of the palm genus, Podococcus, to assess the role of past climate variation on their distribution and genetic diversity. Species distribution modeling in the present and at the LGM was used to estimate areas of climatic stability. Genetic diversity and phylogeography were estimated by sequencing near complete plastomes for over 120 individuals. Areas of climatic stability were mainly located in mountainous areas like the Monts de Cristal and Monts Doudou in Gabon, but also lowland coastal forests in southeast Cameroon and northeast Gabon. Genetic diversity analyses shows a clear North-South structure of genetic diversity within one species. This divide was estimated to have originated some 500,000years ago. We show that, in Central Africa, high and unique genetic diversity is strongly correlated with inferred areas of climatic stability since the LGM. Our results further highlight the importance of coastal lowland rain forests in Central Africa as harboring not only high species diversity but also important high levels of unique genetic diversity. In the context of strong human pressure on coastal land use and destruction, such unique diversity hotspots need to be considered in future conservation planning.

  16. Nutrient additions to a tropical rain forest drive substantial soil carbon dioxide losses to the atmosphere

    PubMed Central

    Cleveland, Cory C.; Townsend, Alan R.

    2006-01-01

    Terrestrial biosphere–atmosphere carbon dioxide (CO2) exchange is dominated by tropical forests, where photosynthetic carbon (C) uptake is thought to be phosphorus (P)-limited. In P-poor tropical forests, P may also limit organic matter decomposition and soil C losses. We conducted a field-fertilization experiment to show that P fertilization stimulates soil respiration in a lowland tropical rain forest in Costa Rica. In the early wet season, when soluble organic matter inputs to soil are high, P fertilization drove large increases in soil respiration. Although the P-stimulated increase in soil respiration was largely confined to the dry-to-wet season transition, the seasonal increase was sufficient to drive an 18% annual increase in CO2 efflux from the P-fertilized plots. Nitrogen (N) fertilization caused similar responses, and the net increases in soil respiration in response to the additions of N and P approached annual soil C fluxes in mid-latitude forests. Human activities are altering natural patterns of tropical soil N and P availability by land conversion and enhanced atmospheric deposition. Although our data suggest that the mechanisms driving the observed respiratory responses to increased N and P may be different, the large CO2 losses stimulated by N and P fertilization suggest that knowledge of such patterns and their effects on soil CO2 efflux is critical for understanding the role of tropical forests in a rapidly changing global C cycle. PMID:16793925

  17. Valuation of consumption and sale of forest goods from a Central American rain forest

    PubMed

    Godoy; Wilkie; Overman; Cubas; Cubas; Demmer; McSweeney; Brokaw

    2000-07-01

    Researchers recognize that society needs accurate and comprehensive estimates of the economic value of rain forests to assess conservation and management options. Valuation of forests can help us to decide whether to implement policies that reconcile the value different groups attach to forests. Here we have measured the value of the rain forest to local populations by monitoring the foods, construction and craft materials, and medicines consumed or sold from the forest by 32 Indian households in two villages in Honduras over 2.5 years. We have directly measured the detailed, comprehensive consumption patterns of rain forest products by an indigenous population and the value of that consumption in local markets. The combined value of consumption and sale of forest goods ranged from US$17.79 to US$23.72 per hectare per year, at the lower end of previous estimates (between US$49 and US$1,089 (mean US$347) per hectare per year). Although outsiders value the rain forest for its high-use and non-use values, local people receive a small share of the total value. Unless rural people are paid for the non-local values of rain forests, they may be easily persuaded to deforest.

  18. Valuation of consumption and sale of forest goods from a Central American rain forest

    PubMed

    Godoy; Wilkie; Overman; Cubas; Cubas; Demmer; McSweeney; Brokaw

    2000-07-01

    Researchers recognize that society needs accurate and comprehensive estimates of the economic value of rain forests to assess conservation and management options. Valuation of forests can help us to decide whether to implement policies that reconcile the value different groups attach to forests. Here we have measured the value of the rain forest to local populations by monitoring the foods, construction and craft materials, and medicines consumed or sold from the forest by 32 Indian households in two villages in Honduras over 2.5 years. We have directly measured the detailed, comprehensive consumption patterns of rain forest products by an indigenous population and the value of that consumption in local markets. The combined value of consumption and sale of forest goods ranged from US$17.79 to US$23.72 per hectare per year, at the lower end of previous estimates (between US$49 and US$1,089 (mean US$347) per hectare per year). Although outsiders value the rain forest for its high-use and non-use values, local people receive a small share of the total value. Unless rural people are paid for the non-local values of rain forests, they may be easily persuaded to deforest. PMID:10894540

  19. Reproductive activity of ruffed lemurs (Varecia variegata variegata) in a Madagascar rain forest.

    PubMed

    Morland, H S

    1993-05-01

    Mating activity was observed during four breeding seasons in two groups of black and white ruffed lemurs (Varecia variegata variegata) living in lowland rain forest on Nosy Mangabe island, Madagascar. The onset of the May-July breeding season was signalled by behavioral changes in adult males. Males made forays outside their usual home ranges, were more aggressive to other males, and performed appetitive and other sex-specific behaviors more frequently. Females showed receptive and proceptive behaviors during a 1-2 day behavioral estrus. Ruffed lemurs mated monogamously, polyandrously, and polygynously. These observations do not support previous assertions that they live only in monogamous families. Limited evidence suggests females exercised mate choice and may have preferred familiar males.

  20. Seasonal Variation in Seed Dispersal by Tamarins Alters Seed Rain in a Secondary Rain Forest

    PubMed Central

    Muñoz Lazo, Fernando Julio João; Huynen, Marie-Claude; Poncin, Pascal; Heymann, Eckhard W.

    2010-01-01

    Reduced dispersal of large seeds into degraded areas is one of the major factors limiting rain forest regeneration, as many seed dispersers capable of transporting large seeds avoid these sites with a limited forest cover. However, the small size of tamarins allows them to use small trees, and hence to disperse seeds into young secondary forests. Seasonal variations in diet and home range use might modify their contribution to forest regeneration through an impact on the seed rain. For a 2-yr period, we followed a mixed-species group of tamarins in Peru to determine how their role as seed dispersers in a 9-yr-old secondary-growth forest varied across seasons. These tamarins dispersed small to large seeds of 166 tree species, 63 of which were into a degraded area. Tamarins’ efficiency in dispersing seeds from primary to secondary forest varied across seasons. During the late wet season, high dietary diversity and long forays in secondary forest allowed them to disperse large seeds involved in later stages of regeneration. This occurred precisely when tamarins spent a more equal amount of time eating a high diversity of fruit species in primary forest and pioneer species in secondary forest. We hypothesized that well-balanced fruit availability induced the movement of seed dispersers between these 2 habitats. The noteworthy number of large-seeded plant species dispersed by such small primates suggests that tamarins play an important, but previously neglected, role in the regeneration and maintenance of forest structure. Electronic supplementary material The online version of this article (doi:10.1007/s10764-010-9413-7) contains supplementary material, which is available to authorized users. PMID:20651905

  1. The Effects of Acid Rain on Forest Nutrient Status

    NASA Astrophysics Data System (ADS)

    Johnson, Dale W.; Turner, John; Kelly, J. M.

    1982-06-01

    The effects of acidic atmospheric inputs on forest nutrient status must be assessed within the context of natural, internal acid production by carbonic and organic acids as well as the nutrient inputs and drains by management practices such as harvesting, fire, and fertilization. In all cases the anion associated with acid inputs must be mobile in the soil if leaching is to occur; immobilization of anions can effectively prevent cation leaching. Soil acidification will occur only if the often substantial buffering capacity of the soil in question is exceeded by acid inputs and if cation weathering from primary minerals is insufficient to offset cation losses by leaching. Such circumstances are rare but certainly could occur in theory, at least, given sufficiently large acid inputs on poorly buffered soils. Soils most sensitive to change are thought to be those of moderately acid pH and low cation exchange capacity. Neither very acid soils nor neutral, highly buffered soils are sensitive to acidification by acid rain. Given extremely high acid inputs, acid rain can cause temporary increases in nitrogen mineralization and nitritication as well as Al mobilization in soils. While temporary increases in N availability can cause increased forest growth in N-deficient forests, increased Al availability can cause toxic reactions in tree roots. Little is known about tree Al toxicity levels as yet, however. It must be emphasized that assessment of acid rain effects is a problem of quantification. Given sufficiently high inputs on sensitive sites, negative effects of acid rain must occur, as is true of inputs of any substance, including H2O. Acid rain inputs of sufficient magnitude to cause acute effects, such as growth increase due to N mobilization or growth decrease due to Al mobilization, are apparently very rare under ambient field conditions. Long-term effects on forest nutrient status can be either beneficial or adverse, depending on site nutrient status, silvicultural

  2. Leaf structural diversity is related to hydraulic capacity in tropical rain forest trees.

    PubMed

    Sack, Lawren; Frole, Kristen

    2006-02-01

    The hydraulic resistance of the leaf (R1) is a major bottleneck in the whole plant water transport pathway and may thus be linked with the enormous variation in leaf structure and function among tropical rain forest trees. A previous study found that R1 varied by an order of magnitude across 10 tree species of Panamanian tropical lowland rain forest. Here, correlations were tested between R1 and 24 traits relating to leaf venation and mesophyll structure, and to gross leaf form. Across species, R1 was related to both venation architecture and mesophyll structure. R1 was positively related to the theoretical axial resistivity of the midrib, determined from xylem conduit numbers and dimensions, and R1 was negatively related to venation density in nine of 10 species. R1 was also negatively related to both palisade mesophyll thickness and to the ratio of palisade to spongy mesophyll. By contrast, numerous leaf traits were independent of R1, including area, shape, thickness, and density, demonstrating that leaves can be diverse in gross structure without intrinsic trade-offs in hydraulic capacity. Variation in both R1-linked and R1-independent traits related strongly to regeneration irradiance, indicating the potential importance of both types of traits in establishment ecology.

  3. Stem and leaf hydraulic properties are finely coordinated in three tropical rain forest tree species.

    PubMed

    Nolf, Markus; Creek, Danielle; Duursma, Remko; Holtum, Joseph; Mayr, Stefan; Choat, Brendan

    2015-12-01

    Coordination of stem and leaf hydraulic traits allows terrestrial plants to maintain safe water status under limited water supply. Tropical rain forests, one of the world's most productive biomes, are vulnerable to drought and potentially threatened by increased aridity due to global climate change. However, the relationship of stem and leaf traits within the plant hydraulic continuum remains understudied, particularly in tropical species. We studied within-plant hydraulic coordination between stems and leaves in three tropical lowland rain forest tree species by analyses of hydraulic vulnerability [hydraulic methods and ultrasonic emission (UE) analysis], pressure-volume relations and in situ pre-dawn and midday water potentials (Ψ). We found finely coordinated stem and leaf hydraulic features, with a strategy of sacrificing leaves in favour of stems. Fifty percent of hydraulic conductivity (P50 ) was lost at -2.1 to -3.1 MPa in stems and at -1.7 to -2.2 MPa in leaves. UE analysis corresponded to hydraulic measurements. Safety margins (leaf P50 - stem P50 ) were very narrow at -0.4 to -1.4 MPa. Pressure-volume analysis and in situ Ψ indicated safe water status in stems but risk of hydraulic failure in leaves. Our study shows that stem and leaf hydraulics were finely tuned to avoid embolism formation in the xylem.

  4. Nitrate reduction in sediments of lowland tropical streams draining swamp forest in Costa Rica: An ecosystem perspective

    USGS Publications Warehouse

    Duff, J.H.; Pringle, C.M.; Triska, F.J.

    1996-01-01

    Nitrate reduction and denitrification were measured in swamp forest streams draining lowland rain forest on Costa Rica's Atlantic slope foothills using the C2H2-block assay and sediment-water nutrient fluxes. Denitrification assays using the C2H2-block technique indicated that the full suite of denitrifying enzymes were present in the sediment but that only a small fraction of the functional activity could be expressed without adding NO3/-. Under optimal conditions, denitrification enzyme activity averaged 15 nmoles cm-3 sediment h-1. Areal NO3/- reduction rates measured from NO3/- loss in the overlying water of sediment- water flux chambers ranged from 65 to 470 umoles m-2 h-1. Oxygen loss rates accompanying NO3/-depletion averaged 750 umoles m-2 h-1. Corrected for denitrification of NO3/- oxidized from NH4/+ in the sediment, gross NO3/- reduction rates increase by 130 umoles m-2 h-1, indicating nitrification may be the predominant source of NO3/- for NO3/- reduction in swamp forest stream sediments. Under field conditions approximately 80% of the increase in inorganic N mass along a 1250-m reach of the Salto River was in the form of NO3/- with the balance NH4/+. Scrutiny of potential inorganic N sources suggested that mineralized N released from the streambed was a major source of the inorganic N increase. Despite significant NO3/- reduction potential, swamp forest stream sediments appear to be a source of inorganic N to downstream communities.

  5. BIOGENIC VOLATILE ORGANIC COMPOUND EMISSIONS FROM A LOWLAND TROPICAL WET FOREST IN COSTA RICA

    EPA Science Inventory

    Twenty common plant species were screened for emissions of biogenic volatile organic compounds (BVOCS) at a lowland tropical wet forest site in Costa Rica. Ten of the species. examined emitted substantial quantities of isoprene. These species accounted for 35-50% of the total bas...

  6. Bird communities associated with succession and management of lowland conifer forests

    USGS Publications Warehouse

    Dawson, D.K.

    1979-01-01

    Data from published bird censuses were used to determine changes in avian communities in relation to plant succession, fire, type conversion, and timber management practices in lowland conifer forests in the northeastern United States. With modifications in current logging practices, habitat for the bird species that nest in undisturbed stands can be provided. Management guidelines are recommended.

  7. Current and Future Carbon Budgets of Tropical Rain Forest: A Cross Scale Analysis. Final Report

    SciTech Connect

    Oberbauer, S. F.

    2004-01-16

    The goal of this project was to make a first assessment of the major carbon stocks and fluxes and their climatic determinants in a lowland neotropical rain forest, the La Selva Biological Station, Costa Rica. Our research design was based on the concurrent use of several of the best available approaches, so that data could be cross-validated. A major focus of our effort was to combine meteorological studies of whole-forest carbon exchange (eddy flux), with parallel independent measurements of key components of the forest carbon budget. The eddy flux system operated from February 1998 to February 2001. To obtain field data that could be scaled up to the landscape level, we monitored carbon stocks, net primary productivity components including tree growth and mortality, litterfall, woody debris production, root biomass, and soil respiration in a series of replicated plots stratified across the major environmental gradients of the forest. A second major focus of this project was on the stocks and changes of carbon in the soil. We used isotope studies and intensive monitoring to investigate soil organic stocks and the climate-driven variation of soil respiration down the soil profile, in a set of six 4m deep soil shafts stratified across the landscape. We measured short term tree growth, climate responses of sap flow, and phenology in a suite of ten canopy trees to develop individual models of tree growth to daytime weather variables.

  8. Pennsylvanian tropical rain forests responded to glacial-interglacial rhythms

    NASA Astrophysics Data System (ADS)

    Falcon-Lang, Howard J.

    2004-08-01

    Pennsylvanian tropical rain forests flourished during an icehouse climate mode. Although it is well established that Milankovitch-band glacial-interglacial rhythms caused marked synchronous changes in Pennsylvanian tropical climate and sea level, little is known of vegetation response to orbital forcing. This knowledge gap has now been addressed through sequence- stratigraphic analysis of megafloral and palynofloral assemblages within the Westphalian D Cantabrian Sydney Mines Formation of eastern Canada. This succession was deposited in a low- accommodation setting where sequences can be attributed confidently to glacio-eustasy. Results show that long-lived, low-diversity peat mires dominated by lycopsids were initiated during deglaciation events, but were mostly drowned by rising sea level at maximum interglacial conditions. Only upland coniferopsid forests survived flooding without significant disturbance. Mid- to late interglacial phases witnessed delta-plain progradation and establishment of high-diversity, mineral-substrate rain forests containing lycopsids, sphenopsids, pteridosperms, cordaites, and tree ferns. Renewed glaciation resulted in sea-level fall, paleovalley incision, and the onset of climatic aridity. Glacial vegetation was dominated by cordaites, pteridosperms, and tree ferns; hydrophilic lycopsids and sphenopsids survived in paleovalley refugia. Findings clearly demonstrate the dynamic nature of Pennsylvanian tropical ecosystems and are timely given current debates about the impact of Quaternary glacial-interglacial rhythms on the biogeography of tropical rain forest.

  9. Dimethyl sulfide in the Amazon rain forest

    NASA Astrophysics Data System (ADS)

    Jardine, K.; Yañez-Serrano, A. M.; Williams, J.; Kunert, N.; Jardine, A.; Taylor, T.; Abrell, L.; Artaxo, P.; Guenther, A.; Hewitt, C. N.; House, E.; Florentino, A. P.; Manzi, A.; Higuchi, N.; Kesselmeier, J.; Behrendt, T.; Veres, P. R.; Derstroff, B.; Fuentes, J. D.; Martin, S. T.; Andreae, M. O.

    2015-01-01

    Surface-to-atmosphere emissions of dimethyl sulfide (DMS) may impact global climate through the formation of gaseous sulfuric acid, which can yield secondary sulfate aerosols and contribute to new particle formation. While oceans are generally considered the dominant sources of DMS, a shortage of ecosystem observations prevents an accurate analysis of terrestrial DMS sources. Using mass spectrometry, we quantified ambient DMS mixing ratios within and above a primary rainforest ecosystem in the central Amazon Basin in real-time (2010-2011) and at high vertical resolution (2013-2014). Elevated but highly variable DMS mixing ratios were observed within the canopy, showing clear evidence of a net ecosystem source to the atmosphere during both day and night in both the dry and wet seasons. Periods of high DMS mixing ratios lasting up to 8 h (up to 160 parts per trillion (ppt)) often occurred within the canopy and near the surface during many evenings and nights. Daytime gradients showed mixing ratios (up to 80 ppt) peaking near the top of the canopy as well as near the ground following a rain event. The spatial and temporal distribution of DMS suggests that ambient levels and their potential climatic impacts are dominated by local soil and plant emissions. A soil source was confirmed by measurements of DMS emission fluxes from Amazon soils as a function of temperature and soil moisture. Furthermore, light- and temperature-dependent DMS emissions were measured from seven tropical tree species. Our study has important implications for understanding terrestrial DMS sources and their role in coupled land-atmosphere climate feedbacks.

  10. The effects of acid rain on forest nutrient status

    SciTech Connect

    Johnson, D.W.; Turner, J.; Kelly, J.M.

    1982-06-01

    The effects of acidic atmospheric inputs on forest nutrient status must be assessed within the context of natural, internal acid production by carbonic and organic acids as well as the nutrient inputs and drains by management practices such as harvesting, fire, and fertilization. Soil acidification will occur only if the often substantial buffering capacity of the soil in question is exceeded by acid inputs and if cation weathering from primary minerals is insufficient to offset cation losses by leaching. Such circumstances are rare but certainly could occur given sufficiently large acid inputs on poorly buffered soils. Soils most sensitive to change are thought to be those of moderately acid pH and low cation exchange capacity. Neither very acid soils nor neutral, highly buffered soils are sensitive to acidification by acid rain. Given extremely high acid inputs, acid rain can cause temporary increases in nitrogen mineralization and nitrification as well as Al mobilization in soils. While temporary increases in N availability can cause increased forest growth in N-deficient forests, increased Al availability can cause toxic reactions in tree roots. Given sufficiently high inputs on sensitive sites, negative effects of acid rain must occur, as is true of inputs of any substance, including H/sub 2/O. Acid rain inputs of sufficient magnitude to cause acute effects, such as growth increase due to N mobilization or growth decrease due to Al mobilization, are apparently very rare under ambient field conditions. Long-term effects on forest nutrient status can be either beneficial or adverse, depending on site nutrient status, silvicultural practices, and amount of atmospheric inputs. (JMT)

  11. Protecting rain forests and forager's rights using LANDSAT imagery

    NASA Technical Reports Server (NTRS)

    Wilkie, David S.

    1991-01-01

    Creating rain forest reserves is vital given the global decline in biodiversity. Yet, the plants and animals that will be protected from untrammeled commercial exploitation within such reserves constitute essential resources for indigenous foragers and farmers. Balancing the needs of local subsistence level populations with the goals of national and international conservation agencies requires a thorough understanding of the mutual impacts that arise from the interaction of park and people. In the Ituri forest of Zaire, LANDSAT TM image analysis and GPS ground truth data were used to locate human settlements so that boundaries of the proposed Okapi Reserve could be chosen to minimize its impact on the subsistence practices of the local foragers and farmers. Using satellite imagery in conjunction with cultural information should help to ensure traditional resource exploitation rights of indigenous peoples whilst simultaneously protecting the largest contiguous area of undisturbed forest.

  12. Fungal community composition in neotropical rain forests: the influence of tree diversity and precipitation.

    PubMed

    McGuire, Krista L; Fierer, Noah; Bateman, Carling; Treseder, Kathleen K; Turner, Benjamin L

    2012-05-01

    Plant diversity is considered one factor structuring soil fungal communities because the diversity of compounds in leaf litter might determine the extent of resource heterogeneity for decomposer communities. Lowland tropical rain forests have the highest plant diversity per area of any biome. Since fungi are responsible for much of the decomposition occurring in forest soils, understanding the factors that structure fungi in tropical forests may provide valuable insight for predicting changes in global carbon and nitrogen fluxes. To test the role of plant diversity in shaping fungal community structure and function, soil (0-20 cm) and leaf litter (O horizons) were collected from six established 1-ha forest census plots across a natural plant diversity gradient on the Isthmus of Panama. We used 454 pyrosequencing and phospholipid fatty acid analysis to evaluate correlations between microbial community composition, precipitation, soil nutrients, and plant richness. In soil, the number of fungal taxa increased significantly with increasing mean annual precipitation, but not with plant richness. There were no correlations between fungal communities in leaf litter and plant diversity or precipitation, and fungal communities were found to be compositionally distinct between soil and leaf litter. To directly test for effects of plant species richness on fungal diversity and function, we experimentally re-created litter diversity gradients in litter bags with 1, 25, and 50 species of litter. After 6 months, we found a significant effect of litter diversity on decomposition rate between one and 25 species of leaf litter. However, fungal richness did not track plant species richness. Although studies in a broader range of sites is required, these results suggest that precipitation may be a more important factor than plant diversity or soil nutrient status in structuring tropical forest soil fungal communities.

  13. Fungal community composition in neotropical rain forests: the influence of tree diversity and precipitation.

    PubMed

    McGuire, Krista L; Fierer, Noah; Bateman, Carling; Treseder, Kathleen K; Turner, Benjamin L

    2012-05-01

    Plant diversity is considered one factor structuring soil fungal communities because the diversity of compounds in leaf litter might determine the extent of resource heterogeneity for decomposer communities. Lowland tropical rain forests have the highest plant diversity per area of any biome. Since fungi are responsible for much of the decomposition occurring in forest soils, understanding the factors that structure fungi in tropical forests may provide valuable insight for predicting changes in global carbon and nitrogen fluxes. To test the role of plant diversity in shaping fungal community structure and function, soil (0-20 cm) and leaf litter (O horizons) were collected from six established 1-ha forest census plots across a natural plant diversity gradient on the Isthmus of Panama. We used 454 pyrosequencing and phospholipid fatty acid analysis to evaluate correlations between microbial community composition, precipitation, soil nutrients, and plant richness. In soil, the number of fungal taxa increased significantly with increasing mean annual precipitation, but not with plant richness. There were no correlations between fungal communities in leaf litter and plant diversity or precipitation, and fungal communities were found to be compositionally distinct between soil and leaf litter. To directly test for effects of plant species richness on fungal diversity and function, we experimentally re-created litter diversity gradients in litter bags with 1, 25, and 50 species of litter. After 6 months, we found a significant effect of litter diversity on decomposition rate between one and 25 species of leaf litter. However, fungal richness did not track plant species richness. Although studies in a broader range of sites is required, these results suggest that precipitation may be a more important factor than plant diversity or soil nutrient status in structuring tropical forest soil fungal communities. PMID:22080256

  14. Leaf litter disappearance in a tropical montane rain forest

    SciTech Connect

    La Caro, F.

    1982-03-01

    The time course of leaf litter disappearance of six rain forest tree species was monitored for 32 weeks at the El Verde lower montane rain forest study site in northeastern Puerto Rico. Dacryodes excelsa, Sloanea berteriana and Drypetes glauca were chosen to represent primary climax species while Cecropia peltata, Inga vera and Ixora ferrea were selected to represent the secondary successional species for this forest. The string non-confined tethered leaf method was employed in this study. Dry weights and concentrations of nitrogen, phosphorus, potassium, calcium and magnesium were determined through seven segments of time. Leaf litter fall and standing crop were estimated and general soil characteristics were measured to provide background data. The secondary species Cecropia peltata and Inga vera were found to have slower rates than the primary species Dacryodes excelsa and Sloanea berteriana. The same pattern appeared to emerge between the understory secondary Ixora ferrea and the understory primary Drypetes glauca. The interacting effects of the leaf structural characteristics such as % lignin and % fiber were found to be best correlated with the observed decay rates. Nutrients were considered important in establishing resource quality factors but did not appear to influence decay rates. Instead, nutrient dynamics reflected intervals of element immobilization, mineralization and importation. 82 refs., 13 figs., 12 tabs.

  15. Modelling the Carbon Stocks Estimation of the Tropical Lowland Dipterocarp Forest Using LIDAR and Remotely Sensed Data

    NASA Astrophysics Data System (ADS)

    Zaki, N. A. M.; Latif, Z. A.; Suratman, M. N.; Zainal, M. Z.

    2016-06-01

    Tropical forest embraces a large stock of carbon in the global carbon cycle and contributes to the enormous amount of above and below ground biomass. The carbon kept in the aboveground living biomass of trees is typically the largest pool and the most directly impacted by the anthropogenic factor such as deforestation and forest degradation. However, fewer studies had been proposed to model the carbon for tropical rain forest and the quantification still remain uncertainties. A multiple linear regression (MLR) is one of the methods to define the relationship between the field inventory measurements and the statistical extracted from the remotely sensed data which is LiDAR and WorldView-3 imagery (WV-3). This paper highlight the model development from fusion of multispectral WV-3 with the LIDAR metrics to model the carbon estimation of the tropical lowland Dipterocarp forest of the study area. The result shown the over segmentation and under segmentation value for this output is 0.19 and 0.11 respectively, thus D-value for the classification is 0.19 which is 81%. Overall, this study produce a significant correlation coefficient (r) between Crown projection area (CPA) and Carbon stocks (CS); height from LiDAR (H_LDR) and Carbon stocks (CS); and Crown projection area (CPA) and height from LiDAR (H_LDR) were shown 0.671, 0.709 and 0.549 respectively. The CPA of the segmentation found to be representative spatially with higher correlation of relationship between diameter at the breast height (DBH) and carbon stocks which is Pearson Correlation p = 0.000 (p < 0.01) with correlation coefficient (r) is 0.909 which shown that there a good relationship between carbon and DBH predictors to improve the inventory estimates of carbon using multiple linear regression method. The study concluded that the integration of WV-3 imagery with the CHM raster based LiDAR were useful in order to quantify the AGB and carbon stocks for a larger sample area of the Lowland Dipterocarp forest.

  16. Forest structure and carbon dynamics in Amazonian tropical rain forests.

    PubMed

    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

    2004-08-01

    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

  17. Forest structure and carbon dynamics in Amazonian tropical rain forests.

    PubMed

    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

    2004-08-01

    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

  18. Ice-age rain forest found moist, cooler

    SciTech Connect

    Kerr, R.A.

    1996-10-04

    Climate researchers have argued for years about whether the tropics cooled a little or a lot during the height of the last ice age 18000 years ago. The answer will offer clues to the sensitivity of the Earth`s climate system to the strengthening greenhouse effect. On a different front, arguments have raged about how the Amazon flora and fauna became so divers. A single study of lake mud from deep in the Amazon rain forest sheds new light on both of these controveries by point toward a cool, but still wet ice age Amazon. This article goes on to discuss the background of the study, other view points, and the implications.

  19. Leaf herbivory and decomposability in a Malaysian tropical rain forest.

    PubMed

    Kurokawa, Hiroko; Nakashizuka, Tohru

    2008-09-01

    There is accumulating evidence that similar suites of plant traits may affect leaf palatability and leaf litter decomposability. However, the possible association between leaf herbivory and litter decomposition rates across species in species-diverse natural ecosystems such as tropical rain forests remains unexplored, despite its importance in estimating the herbivory effects on carbon and nutrient cycling of ecosystems. We found no strong association between leaf herbivory and litter decomposition rates across 40 tree species in a Malaysian tropical rain forest, even though the leaf and litter traits were tightly correlated. This is because the leaf and litter traits related to herbivory and decomposition rates in the field were inconsistent. Leaf toughness accounted for only a small part of the variation in the herbivory rate, whereas a number of litter traits (the leaf mass per area, lignin to nitrogen ratio, and condensed tannin concentration) accurately predicted the decomposition rate across species. These results suggest that herbivory rate across species may not be strongly related to single leaf traits, probably because plant-herbivore interactions in tropical rain forests are highly diverse; on the other hand, plant-decomposer interactions are less specific and can be governed by litter chemicals. We also investigated two factors, phylogeny and tree functional types, that could affect the relationship between herbivory and decomposition across species. Phylogenetic relatedness among the species did not affect the relationship between herbivory and decomposition. In contrast, when the plants were segregated according to their leaf emergence pattern, we found a significant positive relationship between herbivory and decomposition rates for continuous-leafing species. In these species, the condensed tannin to N ratios in leaves and litter were related to herbivory and decomposition rates, respectively. However, we did not observe a similar trend for

  20. Cytotoxic xanthones from Psorospermum molluscum from the Madagascar rain forest.

    PubMed

    Leet, John E; Liu, Xiaohong; Drexler, Dieter M; Cantone, Joseph L; Huang, Stella; Mamber, Stephen W; Fairchild, Craig R; Hussain, Raouf; Newman, David J; Kingston, David G I

    2008-03-01

    Two new cytotoxic xanthones were isolated from extracts of the Madagascar rain forest plant Psorospermum cf. molluscum using bioassay-guided fractionation with the Escherichia coli SOS chromotest. The structures of the new dihydrofuranoxanthones, designated 3',4'-deoxy-4'-chloropsoroxanthin-(3',5'-diol) ( 1) and psoroxanthin ( 4), were determined on the basis of 2D-NMR, MS, and UV spectroscopic data and are structurally related to the psorospermins, a known class of plant antitumor agents. A new hydroxyprenylated xanthone ( 5) is also described. Xanthones 1 and 4 showed selective in vitro cytotoxicity against ABAE cells (bovine endothelial cell line).

  1. Widespread Forest Vertebrate Extinctions Induced by a Mega Hydroelectric Dam in Lowland Amazonia.

    PubMed

    Benchimol, Maíra; Peres, Carlos A

    2015-01-01

    Mega hydropower projects in tropical forests pose a major emergent threat to terrestrial and freshwater biodiversity worldwide. Despite the unprecedented number of existing, under-construction and planned hydroelectric dams in lowland tropical forests, long-term effects on biodiversity have yet to be evaluated. We examine how medium and large-bodied assemblages of terrestrial and arboreal vertebrates (including 35 mammal, bird and tortoise species) responded to the drastic 26-year post-isolation history of archipelagic alteration in landscape structure and habitat quality in a major hydroelectric reservoir of Central Amazonia. The Balbina Hydroelectric Dam inundated 3,129 km2 of primary forests, simultaneously isolating 3,546 land-bridge islands. We conducted intensive biodiversity surveys at 37 of those islands and three adjacent continuous forests using a combination of four survey techniques, and detected strong forest habitat area effects in explaining patterns of vertebrate extinction. Beyond clear area effects, edge-mediated surface fire disturbance was the most important additional driver of species loss, particularly in islands smaller than 10 ha. Based on species-area models, we predict that only 0.7% of all islands now harbor a species-rich vertebrate assemblage consisting of ≥80% of all species. We highlight the colossal erosion in vertebrate diversity driven by a man-made dam and show that the biodiversity impacts of mega dams in lowland tropical forest regions have been severely overlooked. The geopolitical strategy to deploy many more large hydropower infrastructure projects in regions like lowland Amazonia should be urgently reassessed, and we strongly advise that long-term biodiversity impacts should be explicitly included in pre-approval environmental impact assessments.

  2. Widespread Forest Vertebrate Extinctions Induced by a Mega Hydroelectric Dam in Lowland Amazonia

    PubMed Central

    2015-01-01

    Mega hydropower projects in tropical forests pose a major emergent threat to terrestrial and freshwater biodiversity worldwide. Despite the unprecedented number of existing, under-construction and planned hydroelectric dams in lowland tropical forests, long-term effects on biodiversity have yet to be evaluated. We examine how medium and large-bodied assemblages of terrestrial and arboreal vertebrates (including 35 mammal, bird and tortoise species) responded to the drastic 26-year post-isolation history of archipelagic alteration in landscape structure and habitat quality in a major hydroelectric reservoir of Central Amazonia. The Balbina Hydroelectric Dam inundated 3,129 km2 of primary forests, simultaneously isolating 3,546 land-bridge islands. We conducted intensive biodiversity surveys at 37 of those islands and three adjacent continuous forests using a combination of four survey techniques, and detected strong forest habitat area effects in explaining patterns of vertebrate extinction. Beyond clear area effects, edge-mediated surface fire disturbance was the most important additional driver of species loss, particularly in islands smaller than 10 ha. Based on species-area models, we predict that only 0.7% of all islands now harbor a species-rich vertebrate assemblage consisting of ≥80% of all species. We highlight the colossal erosion in vertebrate diversity driven by a man-made dam and show that the biodiversity impacts of mega dams in lowland tropical forest regions have been severely overlooked. The geopolitical strategy to deploy many more large hydropower infrastructure projects in regions like lowland Amazonia should be urgently reassessed, and we strongly advise that long-term biodiversity impacts should be explicitly included in pre-approval environmental impact assessments. PMID:26132139

  3. Air pollution, acid rain, and the future of forests

    SciTech Connect

    Postel, S.

    1984-01-01

    The biosphere is not infinitely resilient. What is happening in the industrial world's fields and forests are signs that fossil-fuel combustion has ecological limits, and that exceeding them exacts a price. Unless energy and environmental strategies begin to reflect this, today's threats are bound to become tomorrow's catastrophes. Given the rapidity with which the forest destruction has unfolded, the relevant question is no longer whether proof of damage from air pollutants or acid rain is irrefutable, but whether the forests are sufficiently threatened to warrant action. Undoubtedly, German foresters would answer with an unequivocal yes. But the real test is whether nations so far spared severe losses will muster the political will to take action to avoid them. By encouraging energy efficiency, recycling, and the development of renewable energy sources, and by burning coal cleanly and only when necessary, nations will help protect their forests, crops, lakes, and people for generations. The connections are real, and so are the consequences of ignoring them.

  4. Fine-root responses to fertilization reveal multiple nutrient limitation in a lowland tropical forest.

    PubMed

    Wurzburger, Nina; Wright, S Joseph

    2015-08-01

    Questions remain as to which soil nutrients limit primary production in tropical forests. Phosphorus (P) has long been considered the primary limiting element in lowland forests, but recent evidence demonstrates substantial heterogeneity in response to nutrient addition, highlighting a need to understand and diagnose nutrient limitation across diverse forests. Fine-root characteristics including their abundance, functional traits, and mycorrhizal symbionts can be highly responsive to changes in soil nutrients and may help to diagnose nutrient limitation. Here, we document the response of fine roots to long-term nitrogen (N), P, and potassium (K) fertilization in a lowland forest in Panama. Because this experiment has demonstrated that N and K together limit tree growth and P limits fine litter production, we hypothesized that fine roots would also respond to nutrient addition. Specifically we hypothesized that N, P, and K addition would reduce the biomass, diameter, tissue density, and mycorrhizal colonization of fine roots, and increase nutrient concentration in root tissue. Most morphological root traits responded to the single addition of K and the paired addition of N and P, with the greatest response to all three nutrients combined. The addition of N, P, and K together reduced fine-root biomass, length, and tissue density, and increased specific root length, whereas root diameter remained unchanged. Nitrogen addition did not alter root N concentration, but P and K addition increased root P and K concentration, respectively. Mycorrhizal colonization of fine roots declined with N, increased with P, and was unresponsive to K addition. Although plant species composition remains unchanged after 14 years of fertilization, fine-root characteristics responded to N, P, and K addition, providing some of the strongest stand-level responses in this experiment. Multiple soil nutrients regulate fine-root abundance, morphological and chemical traits, and their association

  5. The food web of a tropical rain forest

    SciTech Connect

    Reagan, D.P.; Waide, R.B.

    1996-12-31

    This book summarizes the natural history and trophic dynamics of a relatively simple tropical rain forest community. The community consists of the plants and animals inhabiting a 40 ha area of forest around the El Verde Field Station in the Luquillo Experimental Forest of Puerto Rico. The understanding is based on three decades (1963 to 1993) of investigations conducted or coordinated by the biologists in the Terrestrial Ecology Division of the University of Puerto Rico (formerly the Center for Energy and Environment Research) and by many visiting scientists who have worked at El Verde. The authors construct a comprehensive food web documenting the relationships among species in this community as a means of organizing the information that`s been collected. Lay-people, students, academics, resource managers, professional scientists, and others interested in the natural history of tropical forests should find points of interest in this book. In addition, ecologists specializing in the study of trophic dynamics are provided with a detailed food web from a biome underrepresented in the available data base and with the interpretations of the importance of this web.

  6. Forest carbon in lowland Papua New Guinea: Local variation and the importance of small trees

    PubMed Central

    Vincent, John B; Henning, Bridget; Saulei, Simon; Sosanika, Gibson; Weiblen, George D

    2015-01-01

    Efforts to incentivize the reduction of carbon emissions from deforestation and forest degradation require accurate carbon accounting. The extensive tropical forest of Papua New Guinea (PNG) is a target for such efforts and yet local carbon estimates are few. Previous estimates, based on models of neotropical vegetation applied to PNG forest plots, did not consider such factors as the unique species composition of New Guinea vegetation, local variation in forest biomass, or the contribution of small trees. We analysed all trees >1 cm in diameter at breast height (DBH) in Melanesia's largest forest plot (Wanang) to assess local spatial variation and the role of small trees in carbon storage. Above-ground living biomass (AGLB) of trees averaged 210.72 Mg  ha−1 at Wanang. Carbon storage at Wanang was somewhat lower than in other lowland tropical forests, whereas local variation among 1-ha subplots and the contribution of small trees to total AGLB were substantially higher. We speculate that these differences may be attributed to the dynamics of Wanang forest where erosion of a recently uplifted and unstable terrain appears to be a major source of natural disturbance. These findings emphasize the need for locally calibrated forest carbon estimates if accurate landscape level valuation and monetization of carbon is to be achieved. Such estimates aim to situate PNG forests in the global carbon context and provide baseline information needed to improve the accuracy of PNG carbon monitoring schemes. PMID:26074730

  7. Air pollution, acid rain, and the future of forests. Part 3. Counting the costs

    SciTech Connect

    Postel, S.

    1984-09-01

    Economic losses are predicted due to the effects of acid rain on forests in Europe and the United States. Growth declines and tree damage on forest lands intensively managed for marketable timber are described. Forest industries which produce paper and other forest products which consume large amounts of energy are said to be reluctant to support acid rain control measures. Few studies have examined the effects of acid deposition combined with intensive forestry practices.

  8. The NASDA Global Rain Forest Mapping (GRFM) Project Releases First CD-ROM

    NASA Technical Reports Server (NTRS)

    Chapman, B.; Taylor, V.; Rosenqvist, A.

    1998-01-01

    The goal of the Global Rain Forest Mapping project (GRFM) is to acquire continuous, high resolution L-band Synthetic Aperture Radar (SAR) imagery of the major tropical rain forests of the world using the Japanese Earth Resources Satellite (JERS-1) SAR.

  9. Rainfall,bulk deposition of nutrients and their seasonal variation in two tropical lowland and montane forests in Borneo

    NASA Astrophysics Data System (ADS)

    Gomyo, M.; Kuraji, K.; Kitayama, K.; Suzuki, M.

    2008-12-01

    The Borneo Island, the third largest in the world, is experiencing rapid and extensive changes driven by population growth and economic expansion. This change has induced the tropical forest conversion to other land uses for subsistence cultivations, large-scale mono crop plantations and the irreversible loss of forest biodiversity. In this paper, we examine rainwater chemistry observed at two different national parks in Malaysian Borneo for 12 months. We present annual bulk nutrient input flux and its seasonality, and the results are compared with data obtained at a number of other locations in the tropics. The possible source of the atmospheric nutrients and factors determining the differences of the two sites in Borneo is discussed. Nutrient fluxes in rainfall were measured two times every week in natural tropical montane rain forest in Mount Kinabalu National Park (MK) and natural tropical lowland rain forest in Lambir Hills National Park (LH) in Malaysian Borneo. Annual rainfall in MK and LH were 3,232 and 2,978 mm yr-1 respectively. Three-month rainfall during the northeast monsoon season in LH was 1.6 times greater than that in MK, whereas the 3- month rainfall during the southwest monsoon season in MK was 2.8 times greater than that in LH. The difference of volume-weighed mean ion concentration of nutrients of rainwater between MK and LH is not significant except Mg and Ca. The correlation coefficient between Na and Cl concentration is greater in LH than in MK suggesting that the rainwater chemistry was affected by mainly marine origin in LH both marine and terrestrial origin in MK. From the comparison of annual flux of nutrients in MK and LH with the other sites in the other tropical sites, it was noted that the Na and Cl flux in LH, which is only 13.7 km from the coast, is relatively low compared with the other sites located less than 20 km from the coast. Classification of nutrients was done by cluster analysis of 3-month nutrient flux in MK and LH and

  10. Phosphorus limits Eucalyptus grandis seedling growth in an unburnt rain forest soil

    PubMed Central

    Tng, David Y. P.; Janos, David P.; Jordan, Gregory J.; Weber, Ellen; Bowman, David M. J. S.

    2014-01-01

    Although rain forest is characterized as pyrophobic, pyrophilic giant eucalypts grow as rain forest emergents in both temperate and tropical Australia. In temperate Australia, such eucalypts depend on extensive, infrequent fires to produce conditions suitable for seedling growth. Little is known, however, about constraints on seedlings of tropical giant eucalypts. We tested whether seedlings of Eucalyptus grandis experience edaphic constraints similar to their temperate counterparts. We hypothesized that phosphorous addition would alleviate edaphic constraints. We grew seedlings in a factorial experiment combining fumigation (to simulate nutrient release and soil pasteurization by fire), soil type (E. grandis forest versus rain forest soil) and phosphorus addition as factors. We found that phosphorus was the principal factor limiting E. grandis seedling survival and growth in rain forest soil, and that fumigation enhanced survival of seedlings in both E. grandis forest and rain forest soil. We conclude that similar to edaphic constraints on temperate giant eucalypts, mineral nutrient and biotic attributes of a tropical rain forest soil may hamper E. grandis seedling establishment. In rain forest soil, E. grandis seedlings benefited from conditions akin to a fire-generated ashbed (i.e., an “ashbed effect”). PMID:25339968

  11. How the formation of Indonesia destroyed Australia's rain forest

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2011-07-01

    A little more than 3 million years ago, a climatic upheaval forever changed Australia's western coast. Over the span of 200,000 years the southward flowing waters of the Leeuwin Current cooled by 2°-3°C, decreasing coastal precipitation and converting northwestern Australia's rain forests to semiarid grasslands. By measuring the isotope ratios and chemical composition of preserved shells left by ancient single-celled organisms, Karas et al. reconstructed the hydrologic signature of the geologic upheaval that triggered the sudden cooling. During the Pliocene (approximately 4-3 million years ago), tectonic activity led to the formation of a number of small islands in the Indonesian Archipelago. This protruding land restricted the Indonesian Throughflow (ITF), a current that carries warm, fresh, tropical Pacific water through the island chain and feeds the Leeuwin Current. (Paleoceanography, doi:10.1029/2010PA001949, 2011)

  12. Air pollution, acid rain, and the future of forests. Part 6. Looking beyond the forest

    SciTech Connect

    Postel, S.

    1984-12-01

    The emerging threat to the world's forests clearly raises the potential economic and ecological consequences of acid rain and air pollution. Because acid rain, ozone, and the buildup of carbon dioxide in the atmosphere are problems with a common origin, they can also have common solutions. Yet most existing and proposed strategies address isolated issues, rather than strive for the integrated solutions that are needed. Placing desulfurizing scrubbers on smokestacks, for example, will reduce sulfur dioxide and thereby control acid rain. But this technology will do nothing to help crops suffering from ozone, nothing to ensure that rain two decades from now will not be just as acidic from nitrogen oxides, and nothing to slow the rate at which carbon dioxide is increasing in the atmosphere. Technological controls for specific pollutants must be part of any plan to reduce emissions substantially in the immediate future. Yet funds are limited, and the time available for reversing these threatening trends grows ever shorter. These problems of common origin must be tackled simultaneously and at their core. Using energy more efficiently, recycling more paper and metals, and generating more power from alternative energy sources are rarely considered in strategies to reduce air pollution or acid rain. Yet they are among the most effective and least costly ways that exist.

  13. Quantifying above- and belowground biomass carbon loss with forest conversion in tropical lowlands of Sumatra (Indonesia).

    PubMed

    Kotowska, Martyna M; Leuschner, Christoph; Triadiati, Triadiati; Meriem, Selis; Hertel, Dietrich

    2015-10-01

    Natural forests in South-East Asia have been extensively converted into other land-use systems in the past decades and still show high deforestation rates. Historically, lowland forests have been converted into rubber forests, but more recently, the dominant conversion is into oil palm plantations. While it is expected that the large-scale conversion has strong effects on the carbon cycle, detailed studies quantifying carbon pools and total net primary production (NPPtotal ) in above- and belowground tree biomass in land-use systems replacing rainforest (incl. oil palm plantations) are rare so far. We measured above- and belowground carbon pools in tree biomass together with NPPtotal in natural old-growth forests, 'jungle rubber' agroforests under natural tree cover, and rubber and oil palm monocultures in Sumatra. In total, 32 stands (eight plot replicates per land-use system) were studied in two different regions. Total tree biomass in the natural forest (mean: 384 Mg ha(-1) ) was more than two times higher than in jungle rubber stands (147 Mg ha(-1) ) and >four times higher than in monoculture rubber and oil palm plantations (78 and 50 Mg ha(-1) ). NPPtotal was higher in the natural forest (24 Mg ha(-1)  yr(-1) ) than in the rubber systems (20 and 15 Mg ha(-1)  yr(-1) ), but was highest in the oil palm system (33 Mg ha(-1)  yr(-1) ) due to very high fruit production (15-20 Mg ha(-1)  yr(-1) ). NPPtotal was dominated in all systems by aboveground production, but belowground productivity was significantly higher in the natural forest and jungle rubber than in plantations. We conclude that conversion of natural lowland forest into different agricultural systems leads to a strong reduction not only in the biomass carbon pool (up to 166 Mg C ha(-1) ) but also in carbon sequestration as carbon residence time (i.e. biomass-C:NPP-C) was 3-10 times higher in the natural forest than in rubber and oil palm plantations. PMID:25980371

  14. Quantifying above- and belowground biomass carbon loss with forest conversion in tropical lowlands of Sumatra (Indonesia).

    PubMed

    Kotowska, Martyna M; Leuschner, Christoph; Triadiati, Triadiati; Meriem, Selis; Hertel, Dietrich

    2015-10-01

    Natural forests in South-East Asia have been extensively converted into other land-use systems in the past decades and still show high deforestation rates. Historically, lowland forests have been converted into rubber forests, but more recently, the dominant conversion is into oil palm plantations. While it is expected that the large-scale conversion has strong effects on the carbon cycle, detailed studies quantifying carbon pools and total net primary production (NPPtotal ) in above- and belowground tree biomass in land-use systems replacing rainforest (incl. oil palm plantations) are rare so far. We measured above- and belowground carbon pools in tree biomass together with NPPtotal in natural old-growth forests, 'jungle rubber' agroforests under natural tree cover, and rubber and oil palm monocultures in Sumatra. In total, 32 stands (eight plot replicates per land-use system) were studied in two different regions. Total tree biomass in the natural forest (mean: 384 Mg ha(-1) ) was more than two times higher than in jungle rubber stands (147 Mg ha(-1) ) and >four times higher than in monoculture rubber and oil palm plantations (78 and 50 Mg ha(-1) ). NPPtotal was higher in the natural forest (24 Mg ha(-1)  yr(-1) ) than in the rubber systems (20 and 15 Mg ha(-1)  yr(-1) ), but was highest in the oil palm system (33 Mg ha(-1)  yr(-1) ) due to very high fruit production (15-20 Mg ha(-1)  yr(-1) ). NPPtotal was dominated in all systems by aboveground production, but belowground productivity was significantly higher in the natural forest and jungle rubber than in plantations. We conclude that conversion of natural lowland forest into different agricultural systems leads to a strong reduction not only in the biomass carbon pool (up to 166 Mg C ha(-1) ) but also in carbon sequestration as carbon residence time (i.e. biomass-C:NPP-C) was 3-10 times higher in the natural forest than in rubber and oil palm plantations.

  15. Ecosystem Consequences of Tree Monodominance for Nitrogen Cycling in Lowland Tropical Forest

    PubMed Central

    Brookshire, E. N. Jack; Thomas, Steven A.

    2013-01-01

    Understanding how plant functional traits shape nutrient limitation and cycling on land is a major challenge in ecology. This is especially true for lowland forest ecosystems of the tropics which can be taxonomically and functionally diverse and rich in bioavailable nitrogen (N). In many tropical regions, however, diverse forests occur side-by-side with monodominant forest (one species >60% of canopy); the long-term biogeochemical consequences of tree monodominance are unclear. Particularly uncertain is whether the monodominant plant-soil system modifies nutrient balance at the ecosystem level. Here, we use chemical and stable isotope techniques to examine N cycling in old-growth Mora excelsa and diverse watershed rainforests on the island of Trinidad. Across 26 small watershed forests and 4 years, we show that Mora monodominance reduces bioavailable nitrate in the plant-soil system to exceedingly low levels which, in turn, results in small hydrologic and gaseous N losses at the watershed-level relative to adjacent N-rich diverse forests. Bioavailable N in soils and streams remained low and remarkably stable through time in Mora forests; N levels in diverse forests, on the other hand, showed high sensitivity to seasonal and inter-annual rainfall variation. Total mineral N losses from diverse forests exceeded inputs from atmospheric deposition, consistent with N saturation, while losses from Mora forests did not, suggesting N limitation. Our measures suggest that this difference cannot be explained by environmental factors but instead by low internal production and efficient retention of bioavailable N in the Mora plant-soil system. These results demonstrate ecosystem-level consequences of a tree species on the N cycle opposite to cases where trees enhance ecosystem N supply via N2 fixation and suggest that, over time, Mora monodominance may generate progressive N draw-down in the plant-soil system. PMID:23936215

  16. Slowed decomposition is biotically mediated in an ectomycorrhizal, tropical rain forest.

    PubMed

    McGuire, Krista L; Zak, Donald R; Edwards, Ivan P; Blackwood, Christopher B; Upchurch, Rima

    2010-11-01

    Bacteria and fungi drive the cycling of plant litter in forests, but little is known about their role in tropical rain forest nutrient cycling, despite the high rates of litter decay observed in these ecosystems. However, litter decay rates are not uniform across tropical rain forests. For example, decomposition can differ dramatically over small spatial scales between low-diversity, monodominant rain forests, and species-rich, mixed forests. Because the climatic patterns and soil parent material are identical in co-occurring mixed and monodominant forests, differences in forest floor accumulation, litter production, and decomposition between these forests may be biotically mediated. To test this hypothesis, we conducted field and laboratory studies in a monodominant rain forest in which the ectomycorrhizal tree Dicymbe corymbosa forms >80% of the canopy, and a diverse, mixed forest dominated by arbuscular mycorrhizal trees. After 2 years, decomposition was significantly slower in the monodominant forest (P < 0.001), but litter production was significantly greater in the mixed forest (P < 0.001). In the laboratory, we found microbial community biomass was greater in the mixed forest (P = 0.02), and the composition of fungal communities was distinct between the two rain forest types (P = 0.001). Sequencing of fungal rDNA revealed a significantly lower richness of saprotrophic fungi in the monodominant forest (19 species) relative to the species-rich forest (84 species); moreover, only 4% percent of fungal sequences occurred in both forests. These results show that nutrient cycling patterns in tropical forests can vary dramatically over small spatial scales, and that changes in microbial community structure likely drive the observed differences in decomposition.

  17. Bibliography on tropical rain forests and the global carbon cycle: Volume 2, South Asia

    SciTech Connect

    Flint, E.P.; Richards, J.F.

    1989-02-01

    This bibliography covers the literature on tropical rain forests,tropical deforestation, land-use change, tropical forest conversion, and shifting cultivation in South Asia (predominantly India, Pakistan, and Bangladesh but also including contributions in Burma, Ceylon, Malaysia, and Sri Lanka). It covers not only rain-forest ecosystems but also other ecosystems that border, derive from, or influence rain forests. The literature included was selected because of its contribution to understanding the global carbon cycle, changes in that cycle, and rain forests' role in that cycle. Journal articles, books, and reports from 1880 to 1988 are included. The more than 4200 entries of this bibliography are ordered alphabetically by author and are indexed by subject and author.

  18. The linkages between photosynthesis, productivity, growth and biomass in lowland Amazonian forests.

    PubMed

    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.

  19. Leaf and soil nitrogen and phosphorus availability in a neotropical rain forest of nutrient-rich soil.

    PubMed

    Martínez-Sánchez, José Luis

    2006-06-01

    The nitrogen and phosphorus supply in a lowland rain forest with a nutrient-rich soil was investigated by means of the leaf N/P quotient. It was hypothesised a high N and P supply to the forest ecosystem with a N and P rich soil. Total N and extractable P were determined in the surface (10 cm) soil of three plots of the forest. Total N was analysed by the Kjeldahl method, and P was extracted with HCI and NH4F. The leaf N/P quotient was evaluated from the senesced leaves of 11 dominant tree species from the mature forest. Samples of 5 g of freshly fallen leaves were collected from three trees of each species. Nitrogen was analysed by microkjeldahl digestion with sulphuric acid and distilled with boric acid, and phosphorus was analysed by digestion with nitric acid and perchloric acid, and determined by photometry. Concentrations of total N (0.50%, n = 30) and extractable P (4.11 microg g(-1), n = 30) in the soil were high. As expected, P supply was sufficient, but contrary to expected, N supply was low (N/P = 11.8, n = 11).

  20. Investigating Appropriate Sampling Design for Estimating Above-Ground Biomass in Bruneian Lowland Mixed Dipterocarp Forest

    NASA Astrophysics Data System (ADS)

    Lee, S.; Lee, D.; Abu Salim, K.; Yun, H. M.; Han, S.; Lee, W. K.; Davies, S. J.; Son, Y.

    2014-12-01

    Mixed tropical forest structure is highly heterogeneous unlike plantation or mixed temperate forest structure, and therefore, different sampling approaches are required. However, the appropriate sampling design for estimating the above-ground biomass (AGB) in Bruneian lowland mixed dipterocarp forest (MDF) has not yet been fully clarified. The aim of this study was to provide supportive information in sampling design for Bruneian forest carbon inventory. The study site was located at Kuala Belalong lowland MDF, which is part of the Ulu Tembulong National Park, Brunei Darussalam. Six 60 m × 60 m quadrats were established, separated by a distance of approximately 100 m and each was subdivided into quadrats of 10 m × 10 m, at an elevation between 200 and 300 m above sea level. At each plot all free-standing trees with diameter at breast height (dbh) ≥ 1 cm were measured. The AGB for all trees with dbh ≥ 10 cm was estimated by allometric models. In order to analyze changes in the diameter-dependent parameters used for estimating the AGB, different quadrat areas, ranging from 10 m × 10 m to 60 m × 60 m, were used across the study area, starting at the South-West end and moving towards the North-East end. The derived result was as follows: (a) Big trees (dbh ≥ 70 cm) with sparse distribution have remarkable contribution to the total AGB in Bruneian lowland MDF, and therefore, special consideration is required when estimating the AGB of big trees. Stem number of trees with dbh ≥ 70 cm comprised only 2.7% of all trees with dbh ≥ 10 cm, but 38.5% of the total AGB. (b) For estimating the AGB of big trees at the given acceptable limit of precision (p), it is more efficient to use large quadrats than to use small quadrats, because the total sampling area decreases with the former. Our result showed that 239 20 m × 20 m quadrats (9.6 ha in total) were required, while 15 60 m × 60 m quadrats (5.4 ha in total) were required when estimating the AGB of the trees

  1. Network of Environmental Sensors in Tropical Rain Forests

    NASA Astrophysics Data System (ADS)

    von Randow, C.; Dos Santos, R. D.; Da Rocha, H.

    2010-12-01

    The interaction between the Earth’s atmosphere and the terrestrial biosphere plays a fundamental role in the climate system and in biogeochemical and hydrological cycles, through the exchange of energy and mass (for example, water and carbon), between the vegetation and the atmospheric boundary layer, and the main focus of many environmental studies is to quantify this exchange over several terrestrial biomes. Over natural surfaces like the tropical forests, factors like spatial variations in topography or in the vegetation cover can significantly affect the air flow and pose big challenges for the monitoring of the regional carbon budget of terrestrial biomes. It is hardly possible to understand the air flow and reduce the uncertainties of flux measurements in complex terrains like tropical forests without an approach that recognizes the complexity of the spatial variability of the environmental variables. With this motivation, a partnership involving Microsoft Research, Johns Hopkins University, University of São Paulo and Instituto Nacional de Pesquisas Espaciais (INPE, the Brazilian national institute for space research) has been developing research activities to test the use of prototypes of environmental sensors (geosensors) in the Atlantic coastal and in the Amazonian rain forests in Brazil, forming sensor networks with high spatial and temporal resolution, and to develop software tools for data quality control and integration. The main premise is that the geosensors should have relatively low cost, what enables the formation of monitoring networks with a large number of sensors spatially distributed. A pilot study deployed 200+ sensors over the Atlantic coastal forest in Sao Paulo state, Brazil. Here we present the results from this study, highlighting the current discussions on applications of this type of measurements in studies of biosphere-atmosphere interaction in the tropics. Envisioning a possible wide deployment of geosensors in Amazonia in the

  2. Primers of glycosaminoglycan biosynthesis from Peruvian rain forest plants.

    PubMed

    Taylor, W H; Sinha, A; Khan, I A; McDaniel, S T; Esko, J D

    1998-08-28

    We have developed a rapid, high throughput screening assay for compounds that alter the assembly of glycosaminoglycan chains in Chinese hamster ovary cells. The assay uses autoradiography to measure the binding of newly synthesized [35S]proteoglycans and [35S]glycosaminoglycans to a positively charged membrane. Screening over 1000 extracts from a random plant collection obtained from the Amazon rain forest yielded five plants that stimulated glycosaminoglycan assembly in both wild-type cells and a mutant cell line defective in xylosyltransferase (the first committed enzyme involved in glycosaminoglycan biosynthesis). Fractionation of an extract of Maieta guianensis by silica gel and reverse-phase chromatography yielded two pure compounds with stimulatory activity. Spectroscopic analysis by NMR and mass spectrometry revealed that the active principles were xylosides of dimethylated ellagic acid. One of the compounds also contained a galloyl group at C-3 of the xylose moiety. These findings suggest that plants and other natural products may be a source of agents that can potentially alter glycosaminoglycan and proteoglycan formation in animal cells.

  3. Forest roadsides harbour less competitive habitats for a relict mountain plant (Pulsatilla vernalis) in lowlands

    NASA Astrophysics Data System (ADS)

    Zielińska, Katarzyna M.; Kiedrzyński, Marcin; Grzyl, Andrzej; Rewicz, Agnieszka

    2016-08-01

    The long-term survival of relict populations depends on the accessibility of appropriate sites (microrefugia). In recent times, due to the mass extinction of rare species that has resulted from the loss of natural habitats, the question is – Are there any human-made sites that can act as refugial habitats? We examined forest roadside populations of the mountain plant Pulsatilla vernalis in the last large lowland refugium in Central Europe. We compared the habitat conditions and community structure of roadsides with P. vernalis against the forest interior. Light availability and bryophyte composition were the main factors that distinguished roadsides. Pulsatilla occurred on sites that had more light than the forest interior, but were also more or less shaded by trees, so more light came as one-side illumination from the road. Roadsides had also a lower coverage of bryophytes that formed large, dense carpets. At the same time, they were characterised by a greater richness of vascular plants and ‘small’ bryophytes, which corresponds to a higher frequency of disturbances. In a warming and more fertile Anthropocene world, competition plays the main role in the transformation of forest communities, which is why relict populations have found refugia in extensively disturbed human-made habitats.

  4. Forest roadsides harbour less competitive habitats for a relict mountain plant (Pulsatilla vernalis) in lowlands

    PubMed Central

    Zielińska, Katarzyna M.; Kiedrzyński, Marcin; Grzyl, Andrzej; Rewicz, Agnieszka

    2016-01-01

    The long-term survival of relict populations depends on the accessibility of appropriate sites (microrefugia). In recent times, due to the mass extinction of rare species that has resulted from the loss of natural habitats, the question is – Are there any human-made sites that can act as refugial habitats? We examined forest roadside populations of the mountain plant Pulsatilla vernalis in the last large lowland refugium in Central Europe. We compared the habitat conditions and community structure of roadsides with P. vernalis against the forest interior. Light availability and bryophyte composition were the main factors that distinguished roadsides. Pulsatilla occurred on sites that had more light than the forest interior, but were also more or less shaded by trees, so more light came as one-side illumination from the road. Roadsides had also a lower coverage of bryophytes that formed large, dense carpets. At the same time, they were characterised by a greater richness of vascular plants and ‘small’ bryophytes, which corresponds to a higher frequency of disturbances. In a warming and more fertile Anthropocene world, competition plays the main role in the transformation of forest communities, which is why relict populations have found refugia in extensively disturbed human-made habitats. PMID:27534690

  5. Forest roadsides harbour less competitive habitats for a relict mountain plant (Pulsatilla vernalis) in lowlands.

    PubMed

    Zielińska, Katarzyna M; Kiedrzyński, Marcin; Grzyl, Andrzej; Rewicz, Agnieszka

    2016-08-18

    The long-term survival of relict populations depends on the accessibility of appropriate sites (microrefugia). In recent times, due to the mass extinction of rare species that has resulted from the loss of natural habitats, the question is - Are there any human-made sites that can act as refugial habitats? We examined forest roadside populations of the mountain plant Pulsatilla vernalis in the last large lowland refugium in Central Europe. We compared the habitat conditions and community structure of roadsides with P. vernalis against the forest interior. Light availability and bryophyte composition were the main factors that distinguished roadsides. Pulsatilla occurred on sites that had more light than the forest interior, but were also more or less shaded by trees, so more light came as one-side illumination from the road. Roadsides had also a lower coverage of bryophytes that formed large, dense carpets. At the same time, they were characterised by a greater richness of vascular plants and 'small' bryophytes, which corresponds to a higher frequency of disturbances. In a warming and more fertile Anthropocene world, competition plays the main role in the transformation of forest communities, which is why relict populations have found refugia in extensively disturbed human-made habitats.

  6. Forest roadsides harbour less competitive habitats for a relict mountain plant (Pulsatilla vernalis) in lowlands.

    PubMed

    Zielińska, Katarzyna M; Kiedrzyński, Marcin; Grzyl, Andrzej; Rewicz, Agnieszka

    2016-01-01

    The long-term survival of relict populations depends on the accessibility of appropriate sites (microrefugia). In recent times, due to the mass extinction of rare species that has resulted from the loss of natural habitats, the question is - Are there any human-made sites that can act as refugial habitats? We examined forest roadside populations of the mountain plant Pulsatilla vernalis in the last large lowland refugium in Central Europe. We compared the habitat conditions and community structure of roadsides with P. vernalis against the forest interior. Light availability and bryophyte composition were the main factors that distinguished roadsides. Pulsatilla occurred on sites that had more light than the forest interior, but were also more or less shaded by trees, so more light came as one-side illumination from the road. Roadsides had also a lower coverage of bryophytes that formed large, dense carpets. At the same time, they were characterised by a greater richness of vascular plants and 'small' bryophytes, which corresponds to a higher frequency of disturbances. In a warming and more fertile Anthropocene world, competition plays the main role in the transformation of forest communities, which is why relict populations have found refugia in extensively disturbed human-made habitats. PMID:27534690

  7. Calculation of Individual Tree Water Use in a Bornean Tropical Rain Forest Using Individual-Based Dynamic Vegetation Model SEIB-DGVM

    NASA Astrophysics Data System (ADS)

    Nakai, T.; Kumagai, T.; Saito, T.; Matsumoto, K.; Kume, T.; Nakagawa, M.; Sato, H.

    2015-12-01

    Bornean tropical rain forests are among the moistest biomes of the world with abundant rainfall throughout the year, and considered to be vulnerable to a change in the rainfall regime; e.g., high tree mortality was reported in such forests induced by a severe drought associated with the ENSO event in 1997-1998. In order to assess the effect (risk) of future climate change on eco-hydrology in such tropical rain forests, it is important to understand the water use of trees individually, because the vulnerability or mortality of trees against climate change can depend on the size of trees. Therefore, we refined the Spatially Explicit Individual-Based Dynamic Global Vegetation Model (SEIB-DGVM) so that the transpiration and its control by stomata are calculated for each individual tree. By using this model, we simulated the transpiration of each tree and its DBH-size dependency, and successfully reproduced the measured data of sap flow of trees and eddy covariance flux data obtained in a Bornean lowland tropical rain forest in Lambir Hills National Park, Sarawak, Malaysia.

  8. 1997 Canadian acid rain assessment. Volume 4: The effects on Canada`s forests

    SciTech Connect

    Hall, P.

    1997-12-31

    This report reviews the state of acid rain assessment related to Canadian forests as it has progressed since the last assessment carried out in 1990. The assessment also highlights key policy issues and the uncertainties associated with addressing them. Sections of the report cover the following: Acid rain and current forest decline in coastal birch, sugar maple, and high elevation forests; the effects of acid rain on tree physiology and soil chemistry; results of forest health monitoring in national, North American, Ontario, and Quebec networks; the critical loads or levels of acid deposition, with reference to case studies; and international involvement in acid rain research and abatement. Finally, research and information needs are identified.

  9. Tropical rain forest conservation and the twin challenges of diversity and rarity.

    PubMed

    Hubbell, Stephen P

    2013-09-01

    Data from a global network of large, permanent plots in lowland tropical forests demonstrate (1) that the phenomenon of tropical tree rarity is real and (2) that almost all the species diversity in such forests is due to rare species. Theoretical and empirically based reasoning suggests that many of these rare species are not as geographically widespread as previously thought. These findings suggest that successful strategies for conserving global tree diversity in lowland tropical forests must pay much more attention to the biogeography of rarity, as well as to the impact of climate change on the distribution and abundance of rare species. Because the biogeography of many tropical tree species is poorly known, a high priority should be given to documenting the distribution and abundance of rare tropical tree species, particularly in Amazonia, the largest remaining tropical forested region in the world.

  10. Tropical rain forest conservation and the twin challenges of diversity and rarity

    PubMed Central

    Hubbell, Stephen P

    2013-01-01

    Data from a global network of large, permanent plots in lowland tropical forests demonstrate (1) that the phenomenon of tropical tree rarity is real and (2) that almost all the species diversity in such forests is due to rare species. Theoretical and empirically based reasoning suggests that many of these rare species are not as geographically widespread as previously thought. These findings suggest that successful strategies for conserving global tree diversity in lowland tropical forests must pay much more attention to the biogeography of rarity, as well as to the impact of climate change on the distribution and abundance of rare species. Because the biogeography of many tropical tree species is poorly known, a high priority should be given to documenting the distribution and abundance of rare tropical tree species, particularly in Amazonia, the largest remaining tropical forested region in the world. PMID:24223266

  11. The Lethal Fungus Batrachochytrium dendrobatidis Is Present in Lowland Tropical Forests of Far Eastern Panamá

    PubMed Central

    Rebollar, Eria A.; Hughey, Myra C.; Harris, Reid N.; Domangue, Rickie J.; Medina, Daniel; Ibáñez, Roberto; Belden, Lisa K.

    2014-01-01

    The fungal disease chytridiomycosis, caused by Batrachochytrium dendrobatidis (Bd), is one of the main causes of amphibian population declines and extinctions all over the world. In the Neotropics, this fungal disease has caused catastrophic declines in the highlands as it has spread throughout Central America down to Panamá. In this study, we determined the prevalence and intensity of Bd infection in three species of frogs in one highland and four lowland tropical forests, including two lowland regions in eastern Panamá in which the pathogen had not been detected previously. Bd was present in all the sites sampled with a prevalence ranging from 15–34%, similar to other Neotropical lowland sites. The intensity of Bd infection on individual frogs was low, ranging from average values of 0.11–24 zoospore equivalents per site. Our work indicates that Bd is present in anuran communities in lowland Panamá, including the Darién province, and that the intensity of the infection may vary among species from different habitats and with different life histories. The population-level consequences of Bd infection in amphibian communities from the lowlands remain to be determined. Detailed studies of amphibian species from the lowlands will be essential to determine the reason why these species are persisting despite the presence of the pathogen. PMID:24740162

  12. Geologic mapping of Indonesian rain forest with analysis of multiple SIR-B incidence angles

    NASA Technical Reports Server (NTRS)

    Ford, J. P.; Sabins, F. F., Jr.; Asmoro, P., Jr.

    1984-01-01

    The discrimination and mapping capabilities are to be evaluated for shuttle imaging radar-B (SIR-B) images of geologic features in Indonesia that are covered by equatorial rain forest canopy. The SIR-B backscatter from the rain forest at L-band is to be compared to backscatter acquired by the SEASAT scatterometer system at Ku-band ever corresponding areas. The approach for data acquisition, handling, and analysis and the expected results of the investigation are discussed.

  13. Soil-calcium depletion linked to acid rain and forest growth in the eastern United States

    USGS Publications Warehouse

    Lawrence, Gregory B.; Huntington, T.G.

    1999-01-01

    Since the discovery of acid rain in the 1970's, scientists have been concerned that deposition of acids could cause depletion of calcium in forest soils. Research in the 1980's showed that the amount of calcium in forest soils is controlled by several factors that are difficult to measure. Further research in the 1990's, including several studies by the U.S. Geological Survey, has shown that (1) calcium in forest soils has decreased at locations in the northeastern and southeastern U.S., and (2) acid rain and forest growth (uptake of calcium from the soil by roots) are both factors contributing to calcium depletion.

  14. Cryptic diversity in Afro-tropical lowland forests: The systematics and biogeography of the avian genus Bleda.

    PubMed

    Huntley, Jerry W; Voelker, Gary

    2016-06-01

    Recent investigations of distributional patterns of Afro-tropical lowland forest species have demonstrated to some degree our overall lack of understanding involving historical diversification patterns. Traditionally, researchers have relied upon two hypotheses, each of which views the lowland forest of Africa in differing roles. The Pleistocene Forest Refuge Hypothesis (PFRH) posits that biogeographic patterns of avian lowland species are explained via allopatric speciation during forest fragmentation cycles in the Pleistocene epoch (c. 1.8Ma-11,700Ka). The Montane Speciation Hypothesis (MSH) countered by suggesting that lowland forests are "evolutionary museums" where species, which originally evolved in montane forest refuge centers, remained without further diversification. Furthermore, investigations have largely regarded widespread, avian species which lack phenotypic variability as biogeographically "uninformative", with regards to historical biogeographic patterns. To test the tenets of these ideas, we investigated the systematics and biogeography of the genus Bleda, whose constituent species are restricted to lowland forest and are lacking in phenotypic variation. Using extracted DNA from 179 individuals, we amplified two mitochondrial genes and three nuclear loci and utilized Bayesian phylogenetic methods and molecular clock dating to develop a time-calibrated phylogeny of Bleda. We used LaGrange to develop an ancestral area reconstruction for the genus. Haplotype networks for three species were generated using Network. We recovered the four currently recognized species of Bleda, plus a monophyletic B. ugandae, a current sub-species which may warrant full species status. We found that the origins of the genus Bleda are estimated to be in the Upper Guinean forests of West Africa, dating to the Miocene (c. 7.5Ma), while the speciation events for the rest of the genus are dated to the Pliocene (c. 5-1.8Ma). Our analyses recovered discrete and highly

  15. Influence of Fire on Permafrost in Lowland Forests of the Tanana Flats, Interior Alaska

    NASA Astrophysics Data System (ADS)

    Brown, D. N.; Jorgenson, T.; Douglas, T. A.; Romanovsky, V. E.; Kielland, K.; Euskirchen, E. S.; Ruess, R.

    2014-12-01

    The degradation of ice-rich permafrost in lowland ecosystems may have particularly strong ecological impacts due to the potential for thaw settlement and subsequent water impoundment. We examined the effects of fire disturbance on permafrost across a chronosequence of fire scars (1930-2010) in the forested areas of collapse-scar bog complexes in the Tanana Flats of Interior Alaska, and utilized a thermal permafrost model (GIPL) to assess the roles of soil physical properties and historic climate. Field-based calculations of potential thaw settlement following the loss of ice-rich permafrost ranged from 0.4 m to 0.9 m. This subsidence would cause the surface elevations of current day forests to drop, on average, to 0.1 m below the surface water level of adjacent collapse-scar bogs, likely resulting in water impoundment. However, the vulnerability of permafrost to deep thawing and talik formation was variable among fire scars due to heterogeneity in organic layer thickness, soil texture, moisture, and associated thermal properties. Simulated reductions in organic layer thickness predicted talik formation in peat and silt loam-dominated soils, but not in sandy loams. The vulnerability of permafrost to talik formation increased under the climatic conditions since 1970, which were characterized by higher air temperatures. Pronounced permafrost thawing occurred during periods of high snow accumulation, whereas periods of low snow accumulation appeared to facilitate permafrost recovery. Simulations of the complete removal of the organic layer (high severity fire) in silt loam-dominated sites suggested the long-term loss of permafrost under the climate of the last century. Overall, the influence of fire on permafrost in these lowland ecosystems appears to be dependent on soil physical properties, fire severity, and climatic conditions.

  16. Mineral content as a basis for food selection by western lowland gorillas in a forest clearing.

    PubMed

    Magliocca, Florence; Gautier-Hion, Annie

    2002-06-01

    The forests in northwest Republic of Congo contain a number of herbaceous swamp clearings that provide foraging sites for lowland gorillas (G.g. gorilla). A 10-month study at the Maya Nord clearing (Parc National d'Odzala) showed that feeding activities occupied 72% of the time visiting gorillas spent on the clearing. They fed on four plant species: Enydra fluctuans (Asteraceae), Cyperus sp., Pycreus mundtii, and Rhynchospora corymbosa (Cyperaceae) among the 45 species recorded on the clearing. These clearing food species have higher mineral contents (especially Na and Ca) than the dominant Marantaceae species (Haumania liebrechtsiana) that constituted a staple food plant for gorillas in this forest. They also have higher potassium contents and contain less lignin than non-eaten clearing items/species. Finally, the most actively searched for clearing food (Enydra fluctuans) was characterized by the highest amount of Na and Ca. These results suggest that the mineral content (especially in Na, Ca, and/or K) could determine the feeding selectivity of gorillas at the clearing. They also tend to confirm that the amount of fiber plays a deterrent role in food selectivity, as has been found by many authors. The high density of gorillas in that region could result from the combination of the large areas of Marantaceae forests that provide abundant though monotonous food, and the number of clearings that provide sufficient mineral supplies. Clearings should thus be considered as key habitats for the conservation of gorillas. PMID:12111682

  17. Root and arbuscular mycorrhizal mycelial interactions with soil microorganisms in lowland tropical forest.

    PubMed

    Nottingham, Andrew T; Turner, Benjamin L; Winter, Klaus; Chamberlain, Paul M; Stott, Andrew; Tanner, Edmund V J

    2013-07-01

    Tropical forests have high rates of soil carbon cycling, but little information is available on how roots, arbuscular mycorrhizal fungi (AMF), and free-living microorganisms interact and influence organic matter mineralization in these ecosystems. We used mesh ingrowth cores and isotopic tracers in phospholipid fatty acid biomarkers to investigate the effects of roots and AMF mycelia on (1) microbial community composition, microbial carbon utilization, and hydrolytic enzyme activities for large, potted tropical trees and (2) enzyme activities and litter mass loss in a lowland tropical forest. Under the tropical tree, plant-derived carbon was incorporated predominantly into bacterial groups in both rhizosphere and AMF-only soils. Gram-positive bacteria incorporated additional soil-derived carbon in rhizosphere soils, which also contained the highest microbial biomass. For hydrolytic enzymes, β-glucosidase and N-acetyl β-glucosaminidase activities were highest in rhizosphere soils, while phosphomonoesterase activity was highest in AMF-only soil. In the forest, leaf litter mass loss was increased by the presence of roots, but not by the presence of AMF mycelia only. Root-microbial interactions influenced organic matter cycling, with evidence for rhizosphere priming and accelerated leaf litter decomposition in the presence of roots. Although AMF mycelia alone did not stimulate organic matter mineralization, they were a conduit of carbon to other soil microorganisms. PMID:23406337

  18. Mineral content as a basis for food selection by western lowland gorillas in a forest clearing.

    PubMed

    Magliocca, Florence; Gautier-Hion, Annie

    2002-06-01

    The forests in northwest Republic of Congo contain a number of herbaceous swamp clearings that provide foraging sites for lowland gorillas (G.g. gorilla). A 10-month study at the Maya Nord clearing (Parc National d'Odzala) showed that feeding activities occupied 72% of the time visiting gorillas spent on the clearing. They fed on four plant species: Enydra fluctuans (Asteraceae), Cyperus sp., Pycreus mundtii, and Rhynchospora corymbosa (Cyperaceae) among the 45 species recorded on the clearing. These clearing food species have higher mineral contents (especially Na and Ca) than the dominant Marantaceae species (Haumania liebrechtsiana) that constituted a staple food plant for gorillas in this forest. They also have higher potassium contents and contain less lignin than non-eaten clearing items/species. Finally, the most actively searched for clearing food (Enydra fluctuans) was characterized by the highest amount of Na and Ca. These results suggest that the mineral content (especially in Na, Ca, and/or K) could determine the feeding selectivity of gorillas at the clearing. They also tend to confirm that the amount of fiber plays a deterrent role in food selectivity, as has been found by many authors. The high density of gorillas in that region could result from the combination of the large areas of Marantaceae forests that provide abundant though monotonous food, and the number of clearings that provide sufficient mineral supplies. Clearings should thus be considered as key habitats for the conservation of gorillas.

  19. Giant eucalypts - globally unique fire-adapted rain-forest trees?

    PubMed

    Tng, D Y P; Williamson, G J; Jordan, G J; Bowman, D M J S

    2012-11-01

    CONTENTS: Summary    1 I. Introduction    1 II. Giant eucalypts in a global context    2 III. Giant eucalypts - taxonomy and distribution    4 IV. Growth of giant eucalypts    6 V. Fire and regeneration of giant eucalypts    8 VI. Are giant eucalypts different from other rain-forest trees?    9 VII. Conclusions 10 Acknowledgements 11 References 11 SUMMARY: Tree species exceeding 70 m in height are rare globally. Giant gymnosperms are concentrated near the Pacific coast of the USA, while the tallest angiosperms are eucalypts (Eucalyptus spp.) in southern and eastern Australia. Giant eucalypts co-occur with rain-forest trees in eastern Australia, creating unique vegetation communities comprising fire-dependent trees above fire-intolerant rain-forest. However, giant eucalypts can also tower over shrubby understoreys (e.g. in Western Australia). The local abundance of giant eucalypts is controlled by interactions between fire activity and landscape setting. Giant eucalypts have features that increase flammability (e.g. oil-rich foliage and open crowns) relative to other rain-forest trees but it is debatable if these features are adaptations. Probable drivers of eucalypt gigantism are intense intra-specific competition following severe fires, and inter-specific competition among adult trees. However, we suggest that this was made possible by a general capacity of eucalypts for 'hyper-emergence'. We argue that, because giant eucalypts occur in rain-forest climates and share traits with rain-forest pioneers, they should be regarded as long-lived rain-forest pioneers, albeit with a particular dependence on fire for regeneration. These unique ecosystems are of high conservation value, following substantial clearing and logging over 150 yr.

  20. Giant eucalypts - globally unique fire-adapted rain-forest trees?

    PubMed

    Tng, D Y P; Williamson, G J; Jordan, G J; Bowman, D M J S

    2012-11-01

    CONTENTS: Summary    1 I. Introduction    1 II. Giant eucalypts in a global context    2 III. Giant eucalypts - taxonomy and distribution    4 IV. Growth of giant eucalypts    6 V. Fire and regeneration of giant eucalypts    8 VI. Are giant eucalypts different from other rain-forest trees?    9 VII. Conclusions 10 Acknowledgements 11 References 11 SUMMARY: Tree species exceeding 70 m in height are rare globally. Giant gymnosperms are concentrated near the Pacific coast of the USA, while the tallest angiosperms are eucalypts (Eucalyptus spp.) in southern and eastern Australia. Giant eucalypts co-occur with rain-forest trees in eastern Australia, creating unique vegetation communities comprising fire-dependent trees above fire-intolerant rain-forest. However, giant eucalypts can also tower over shrubby understoreys (e.g. in Western Australia). The local abundance of giant eucalypts is controlled by interactions between fire activity and landscape setting. Giant eucalypts have features that increase flammability (e.g. oil-rich foliage and open crowns) relative to other rain-forest trees but it is debatable if these features are adaptations. Probable drivers of eucalypt gigantism are intense intra-specific competition following severe fires, and inter-specific competition among adult trees. However, we suggest that this was made possible by a general capacity of eucalypts for 'hyper-emergence'. We argue that, because giant eucalypts occur in rain-forest climates and share traits with rain-forest pioneers, they should be regarded as long-lived rain-forest pioneers, albeit with a particular dependence on fire for regeneration. These unique ecosystems are of high conservation value, following substantial clearing and logging over 150 yr. PMID:23121314

  1. Biogenic volatile organic compound emissions from a lowland tropical wet forest in Costa Rica

    NASA Astrophysics Data System (ADS)

    Geron, Chris; Guenther, Alex; Greenberg, Jim; Loescher, Henry W.; Clark, Deborah; Baker, Brad

    Twenty common plant species were screened for emissions of biogenic volatile organic compounds (BVOCs) at a lowland tropical wet forest site in Costa Rica. Ten of the species examined emitted substantial quantities of isoprene. These species accounted for 35-50% of the total basal area of old-growth forest on the major edaphic site types, indicating that a high proportion of the canopy leaf area is a source of isoprene. A limited number of canopy-level BVOC flux measurements were also collected by relaxed eddy accumulation (REA). These measurements verify that the forest canopy in this region is indeed a significant source of isoprene. In addition, REA fluxes of methanol and especially acetone were also significant, exceeding model estimates and warranting future investigation at this site. Leaf monoterpene emissions were non-detectable or very low from the species surveyed, and ambient concentrations and REA fluxes likewise were very low. Although the isoprene emission rates reported here are largely consistent with phylogenetic relations found in other studies (at the family, genus, and species levels), two species in the family Mimosaceae, a group previously found to consist largely of non-isoprene emitters, emitted significant quantities of isoprene. One of these, Pentaclethra macroloba (Willd.) Kuntze, is by far the most abundant canopy tree species in the forests of this area, composing 30-40% of the total basal area. The other, Zygia longifolia ( Humb. & Bonpl.) Britton & Rose is a common riparian species. Our results suggest that the source strength of BVOCs is important not only to tropical atmospheric chemistry, but also may be important in determining net ecosystem carbon exchange.

  2. Recovery of forest structure and spectral properties after selective logging in lowland Bolivia.

    PubMed

    Broadbent, Eben N; Zarin, Daniel J; Asner, Gregory P; Peña-Claros, Marielos; Cooper, Amanda; Littell, Ramon

    2006-06-01

    Effective monitoring of selective logging from remotely sensed data requires an understanding of the spatial and temporal thresholds that constrain the utility of those data, as well as the structural and ecological characteristics of forest disturbances that are responsible for those constraints. Here we assess those thresholds and characteristics within the context of selective logging in the Bolivian Amazon. Our study combined field measurements of the spatial and temporal dynamics of felling gaps and skid trails ranging from <1 to 19 months following reduced-impact logging in a forest in lowland Bolivia with remote-sensing measurements from simultaneous monthly ASTER satellite overpasses. A probabilistic spectral mixture model (AutoMCU) was used to derive per-pixel fractional cover estimates of photosynthetic vegetation (PV), non-photosynthetic vegetation (NPV), and soil. Results were compared with the normalized difference in vegetation index (NDVI). The forest studied had considerably lower basal area and harvest volumes than logged sites in the Brazilian Amazon where similar remote-sensing analyses have been performed. Nonetheless, individual felling-gap area was positively correlated with canopy openness, percentage liana coverage, rates of vegetation regrowth, and height of remnant NPV. Both liana growth and NPV occurred primarily in the crown zone of the felling gap, whereas exposed soil was limited to the trunk zone of the gap. In felling gaps >400 m2, NDVI, and the PV and NPV fractions, were distinguishable from unlogged forest values for up to six months after logging; felling gaps <400 m2 were distinguishable for up to three months after harvest, but we were entirely unable to distinguish skid trails from our analysis of the spectral data. PMID:16827009

  3. Recovery of trailside vegetation from trampling in a tropical rain forest

    NASA Astrophysics Data System (ADS)

    Boucher, Douglas H.; Aviles, Jeannette; Chepote, Rafael; Domínguez Gil, Oscar E.; Vilchez, Braulio

    1991-03-01

    Practically no information exists on the impact of human trampling on tropical rain forest vegetation. We studied three trails with varying periods of use and recovery in a tropical rain forest in Costa Rica. Human impact on trailside plants was curvilinearly related to use, as found by other workers in temperate zone vegetation. Recovery in a period of two years and eight months had been rapid, and herbs and seedlings were more abundant along the recovering trail than in undisturbed forest. The results imply that a shifting mosaic of trails, analogous to the mosaic created by light gaps, may be the best management technique to minimize the impact of human visitors in tropical rain forests.

  4. Watering up After Clear-Cutting on Forested Wetlands of the St. Lawrence Lowland

    NASA Astrophysics Data System (ADS)

    Dubé, StéPhane; Plamondon, André P.; Rothwell, Richard L.

    1995-07-01

    Clear-cutting on wetlands of the St. Lawrence lowlands raised the water table levels on seven of the eight studied sites encompassing five forest types and four soil subgroups. Water table levels dropped 3 cm after clear-cutting on the eighth site, which was the wettest site with precut water levels within the top 10 cm. This was explained by evaporation from exposed water surfaces. The magnitude of the water table rises increased with the depth of the precut water table. The seasonal mean and maximum rise were respectively 20 and 52 cm on a poorly drained mineral soil which had the lowest precut water table levels. The smallest rises, with means around 7 cm, were associated with high precut water table on bogs and on fens. The watering up was not reduced on fens where a lateral flow occurs. This study indicated that transition sites between the bogs or fens and the uplands were most susceptible to hydrologic changes after clear-cutting. Watering up was caused by reduced evapotranspiration, of which the major component was interception. The rise of the water table observed in the clear-cut and the bordering forest indicates that clear-cutting in narrow strips is not an effective solution to avoid water table rise. Silvicultural treatments to maintain interception and transpiration by leaving logging debris, small trees, and preestablished regeneration would be more effective.

  5. Convective Draft Structure and Transport Over the Amazonian Rain Forest

    NASA Astrophysics Data System (ADS)

    Scala, John Richard

    1990-01-01

    Field observations acquired during two expeditions to the Amazon rain forest of Brazil (ABLE-2A, ABLE-2B), and two-dimensional moist cloud model simulations are used to determine: (1) the vertical structure of convective up- and downdrafts, (2) the major levels of entrainment and detrainment, and (3) the role of temperature and moisture in convective scale transport over the continental tropics. The thermodynamic and kinematic structure of the convective troposphere is obtained from aircraft surveys flown during the dry season and a surface-based network triangle designed for wet season multi-instrumental sampling. Dry season deep convection develops in an environment marked by a mid-tropospheric minimum in equivalent potential temperature. The available supply of cool, dry air supports penetrating downdrafts which feed propagating gust fronts at the surface. Model results indicate the existence of organized cloud fields characterized by multiple updraft cores. The upward vertical transport of air from the subcloud layer to a broad anvil is accomplished without extensive mid-level detrainment. Undilute cores are required to perform the vertical exchange in the presence of mid-tropospheric heat and moisture sinks. Marked moisture gradients are absent in the well -mixed environment of the wet season. Model predicted column heating budgets suggest the evaporation of rainwater into a rear inflow is insufficient to sustain strong downdrafts or an extensive surface cool pool. Complex mid-tropospheric circulations, particularly the existence of a rotor, account for the observed redistribution of a conservative tracer. Undilute transport of boundary layer air to the upper troposphere is markedly reduced by multiple levels of detrainment. In one case, greater than 50% of the air transported to the anvil region originated at or above 6 km rather than directly from the boundary layer. The vertical distribution of boundary layer aerosols in the presence of convection is

  6. Response of soil respiration to acid rain in forests of different maturity in southern China.

    PubMed

    Liang, Guohua; Liu, Xingzhao; Chen, Xiaomei; Qiu, Qingyan; Zhang, Deqiang; Chu, Guowei; Liu, Juxiu; Liu, Shizhong; Zhou, Guoyi

    2013-01-01

    The response of soil respiration to acid rain in forests, especially in forests of different maturity, is poorly understood in southern China despite the fact that acid rain has become a serious environmental threat in this region in recent years. Here, we investigated this issue in three subtropical forests of different maturity [i.e. a young pine forest (PF), a transitional mixed conifer and broadleaf forest (MF) and an old-growth broadleaved forest (BF)] in southern China. Soil respiration was measured over two years under four simulated acid rain (SAR) treatments (CK, the local lake water, pH 4.5; T1, water pH 4.0; T2, water pH 3.5; and T3, water pH 3.0). Results indicated that SAR did not significantly affect soil respiration in the PF, whereas it significantly reduced soil respiration in the MF and the BF. The depressed effects on both forests occurred mostly in the warm-wet seasons and were correlated with a decrease in soil microbial activity and in fine root biomass caused by soil acidification under SAR. The sensitivity of the response of soil respiration to SAR showed an increasing trend with the progressive maturity of the three forests, which may result from their differences in acid buffering ability in soil and in litter layer. These results indicated that the depressed effect of acid rain on soil respiration in southern China may be more pronounced in the future in light of the projected change in forest maturity. However, due to the nature of this field study with chronosequence design and the related pseudoreplication for forest types, this inference should be read with caution. Further studies are needed to draw rigorous conclusions regarding the response differences among forests of different maturity using replicated forest types.

  7. Response of soil respiration to acid rain in forests of different maturity in southern China.

    PubMed

    Liang, Guohua; Liu, Xingzhao; Chen, Xiaomei; Qiu, Qingyan; Zhang, Deqiang; Chu, Guowei; Liu, Juxiu; Liu, Shizhong; Zhou, Guoyi

    2013-01-01

    The response of soil respiration to acid rain in forests, especially in forests of different maturity, is poorly understood in southern China despite the fact that acid rain has become a serious environmental threat in this region in recent years. Here, we investigated this issue in three subtropical forests of different maturity [i.e. a young pine forest (PF), a transitional mixed conifer and broadleaf forest (MF) and an old-growth broadleaved forest (BF)] in southern China. Soil respiration was measured over two years under four simulated acid rain (SAR) treatments (CK, the local lake water, pH 4.5; T1, water pH 4.0; T2, water pH 3.5; and T3, water pH 3.0). Results indicated that SAR did not significantly affect soil respiration in the PF, whereas it significantly reduced soil respiration in the MF and the BF. The depressed effects on both forests occurred mostly in the warm-wet seasons and were correlated with a decrease in soil microbial activity and in fine root biomass caused by soil acidification under SAR. The sensitivity of the response of soil respiration to SAR showed an increasing trend with the progressive maturity of the three forests, which may result from their differences in acid buffering ability in soil and in litter layer. These results indicated that the depressed effect of acid rain on soil respiration in southern China may be more pronounced in the future in light of the projected change in forest maturity. However, due to the nature of this field study with chronosequence design and the related pseudoreplication for forest types, this inference should be read with caution. Further studies are needed to draw rigorous conclusions regarding the response differences among forests of different maturity using replicated forest types. PMID:23626790

  8. Molecular phylogenetics reveal multiple tertiary vicariance origins of the African rain forest trees

    PubMed Central

    Couvreur, Thomas LP; Chatrou, Lars W; Sosef, Marc SM; Richardson, James E

    2008-01-01

    Background Tropical rain forests are the most diverse terrestrial ecosystems on the planet. How this diversity evolved remains largely unexplained. In Africa, rain forests are situated in two geographically isolated regions: the West-Central Guineo-Congolian region and the coastal and montane regions of East Africa. These regions have strong floristic affinities with each other, suggesting a former connection via an Eocene pan-African rain forest. High levels of endemism observed in both regions have been hypothesized to be the result of either 1) a single break-up followed by a long isolation or 2) multiple fragmentation and reconnection since the Oligocene. To test these hypotheses the evolutionary history of endemic taxa within a rain forest restricted African lineage of the plant family Annonaceae was studied. Molecular phylogenies and divergence dates were estimated using a Bayesian relaxed uncorrelated molecular clock assumption accounting for both calibration and phylogenetic uncertainties. Results Our results provide strong evidence that East African endemic lineages of Annonaceae have multiple origins dated to significantly different times spanning the Oligocene and Miocene epochs. Moreover, these successive origins (c. 33, 16 and 8 million years – Myr) coincide with known periods of aridification and geological activity in Africa that would have recurrently isolated the Guineo-Congolian rain forest from the East African one. All East African taxa were found to have diversified prior to Pleistocene times. Conclusion Molecular phylogenetic dating analyses of this large pan-African clade of Annonaceae unravels an interesting pattern of diversification for rain forest restricted trees co-occurring in West/Central and East African rain forests. Our results suggest that repeated reconnections between the West/Central and East African rain forest blocks allowed for biotic exchange while the break-ups induced speciation via vicariance, enhancing the levels of

  9. Interactive effects of wildfire and climate on permafrost degradation in Alaskan lowland forests

    NASA Astrophysics Data System (ADS)

    Brown, Dana R. N.; Jorgenson, M. Torre; Douglas, Thomas A.; Romanovsky, Vladimir E.; Kielland, Knut; Hiemstra, Christopher; Euskirchen, Eugenie S.; Ruess, Roger W.

    2015-08-01

    We examined the effects of fire disturbance on permafrost degradation and thaw settlement across a series of wildfires (from ~1930 to 2010) in the forested areas of collapse-scar bog complexes in the Tanana Flats lowland of interior Alaska. Field measurements were combined with numerical modeling of soil thermal dynamics to assess the roles of fire severity and climate history in postfire permafrost dynamics. Field-based calculations of potential thaw settlement following the loss of remaining ice-rich permafrost averaged 0.6 m. This subsidence would cause the surface elevations of forests to drop on average 0.1 m below the surface water level of adjacent collapse-scar features. Up to 0.5 m of thaw settlement was documented after recent fires, causing water impoundment and further thawing along forest margins. Substantial heterogeneity in soil properties (organic layer thickness, texture, moisture, and ice content) was attributed to differing site histories, which resulted in distinct soil thermal regimes by soil type. Model simulations showed increasing vulnerability of permafrost to deep thawing and thaw settlement with increased fire severity (i.e., reduced organic layer thickness). However, the thresholds of fire severity that triggered permafrost destabilization varied temporally in response to climate. Simulated permafrost dynamics underscore the importance of multiyear to multidecadal fluctuations in air temperature and snow depth in mediating the effects of fire on permafrost. Our results suggest that permafrost is becoming increasingly vulnerable to substantial thaw and collapse after moderate to high-severity fire, and the ability of permafrost to recover is diminishing as the climate continues to warm.

  10. Microbial carbon mineralization in tropical lowland and montane forest soils of Peru

    PubMed Central

    Whitaker, Jeanette; Ostle, Nicholas; McNamara, Niall P.; Nottingham, Andrew T.; Stott, Andrew W.; Bardgett, Richard D.; Salinas, Norma; Ccahuana, Adan J. Q.; Meir, Patrick

    2014-01-01

    Climate change is affecting the amount and complexity of plant inputs to tropical forest soils. This is likely to influence the carbon (C) balance of these ecosystems by altering decomposition processes e.g., “positive priming effects” that accelerate soil organic matter mineralization. However, the mechanisms determining the magnitude of priming effects are poorly understood. We investigated potential mechanisms by adding 13C labeled substrates, as surrogates of plant inputs, to soils from an elevation gradient of tropical lowland and montane forests. We hypothesized that priming effects would increase with elevation due to increasing microbial nitrogen limitation, and that microbial community composition would strongly influence the magnitude of priming effects. Quantifying the sources of respired C (substrate or soil organic matter) in response to substrate addition revealed no consistent patterns in priming effects with elevation. Instead we found that substrate quality (complexity and nitrogen content) was the dominant factor controlling priming effects. For example a nitrogenous substrate induced a large increase in soil organic matter mineralization whilst a complex C substrate caused negligible change. Differences in the functional capacity of specific microbial groups, rather than microbial community composition per se, were responsible for these substrate-driven differences in priming effects. Our findings suggest that the microbial pathways by which plant inputs and soil organic matter are mineralized are determined primarily by the quality of plant inputs and the functional capacity of microbial taxa, rather than the abiotic properties of the soil. Changes in the complexity and stoichiometry of plant inputs to soil in response to climate change may therefore be important in regulating soil C dynamics in tropical forest soils. PMID:25566230

  11. Microbial carbon mineralization in tropical lowland and montane forest soils of Peru.

    PubMed

    Whitaker, Jeanette; Ostle, Nicholas; McNamara, Niall P; Nottingham, Andrew T; Stott, Andrew W; Bardgett, Richard D; Salinas, Norma; Ccahuana, Adan J Q; Meir, Patrick

    2014-01-01

    Climate change is affecting the amount and complexity of plant inputs to tropical forest soils. This is likely to influence the carbon (C) balance of these ecosystems by altering decomposition processes e.g., "positive priming effects" that accelerate soil organic matter mineralization. However, the mechanisms determining the magnitude of priming effects are poorly understood. We investigated potential mechanisms by adding (13)C labeled substrates, as surrogates of plant inputs, to soils from an elevation gradient of tropical lowland and montane forests. We hypothesized that priming effects would increase with elevation due to increasing microbial nitrogen limitation, and that microbial community composition would strongly influence the magnitude of priming effects. Quantifying the sources of respired C (substrate or soil organic matter) in response to substrate addition revealed no consistent patterns in priming effects with elevation. Instead we found that substrate quality (complexity and nitrogen content) was the dominant factor controlling priming effects. For example a nitrogenous substrate induced a large increase in soil organic matter mineralization whilst a complex C substrate caused negligible change. Differences in the functional capacity of specific microbial groups, rather than microbial community composition per se, were responsible for these substrate-driven differences in priming effects. Our findings suggest that the microbial pathways by which plant inputs and soil organic matter are mineralized are determined primarily by the quality of plant inputs and the functional capacity of microbial taxa, rather than the abiotic properties of the soil. Changes in the complexity and stoichiometry of plant inputs to soil in response to climate change may therefore be important in regulating soil C dynamics in tropical forest soils. PMID:25566230

  12. Arbuscular-mycorrhizal networks inhibit Eucalyptus tetrodonta seedlings in rain forest soil microcosms.

    PubMed

    Janos, David P; Scott, John; Aristizábal, Catalina; Bowman, David M J S

    2013-01-01

    Eucalyptus tetrodonta, a co-dominant tree species of tropical, northern Australian savannas, does not invade adjacent monsoon rain forest unless the forest is burnt intensely. Such facilitation by fire of seedling establishment is known as the "ashbed effect." Because the ashbed effect might involve disruption of common mycorrhizal networks, we hypothesized that in the absence of fire, intact rain forest arbuscular mycorrhizal (AM) networks inhibit E. tetrodonta seedlings. Although arbuscular mycorrhizas predominate in the rain forest, common tree species of the northern Australian savannas (including adult E. tetrodonta) host ectomycorrhizas. To test our hypothesis, we grew E. tetrodonta and Ceiba pentandra (an AM-responsive species used to confirm treatments) separately in microcosms of ambient or methyl-bromide fumigated rain forest soil with or without severing potential mycorrhizal fungus connections to an AM nurse plant, Litsea glutinosa. As expected, C. pentandra formed mycorrhizas in all treatments but had the most root colonization and grew fastest in ambient soil. E. tetrodonta seedlings also formed AM in all treatments, but severing hyphae in fumigated soil produced the least colonization and the best growth. Three of ten E. tetrodonta seedlings in ambient soil with intact network hyphae died. Because foliar chlorosis was symptomatic of iron deficiency, after 130 days we began to fertilize half the E. tetrodonta seedlings in ambient soil with an iron solution. Iron fertilization completely remedied chlorosis and stimulated leaf growth. Our microcosm results suggest that in intact rain forest, common AM networks mediate belowground competition and AM fungi may exacerbate iron deficiency, thereby enhancing resistance to E. tetrodonta invasion. Common AM networks-previously unrecognized as contributors to the ashbed effect-probably help to maintain the rain forest-savanna boundary.

  13. Sustainable Harvest and marketing of rain forest products

    SciTech Connect

    Plotkin, M.J.; Famolare, L.M.

    1992-01-01

    The economics of nontimber rainforest products often make a strong case for forest protection and prevention of deforestation. This book contains 33 diverse papers falling into three catagories: tropical rainforests are underutilized sources of new plant products; increased use of tropical forest products should benefit human inhabitants of the rainforest; nontimber forest products many not be the panacea that some suggest.

  14. Topography-specific seed dispersal by Japanese macaques in a lowland forest on Yakushima Island, Japan.

    PubMed

    Tsujino, Riyou; Yumoto, Takakazu

    2009-01-01

    1. We investigated patterns of seed dispersal (i.e. dispersal distances and topography of seed-deposition sites) via the cheek pouches of Japanese macaques (Macaca fuscata yakui) during three seasons in a lowland forest on Yakushima Island, Japan. 2. The mean seed-dispersal distances were 16.7, 26.1, 41.8, and 32.4 m from the trunks of mother trees of Myrica rubra, Persea thunbergii, Neolitsea sericea, and Litsea acuminata, respectively. 3. We assessed the possible effect of macaque foraging patterns and the spatial distribution of fruiting trees on topography-specific seed dispersal. The topography of the locations of macaques differed across seasons, likely because the spatial distribution of fruiting trees determined the seasonal foraging patterns of macaques. 4. In early summer, macaques foraged on a ridge and fed on fruits of M. rubra and P. thunbergii, which were primarily distributed and dispersed within this area. In contrast, during the winter, macaques foraged within a valley and fed on fruits of L. acuminata, which were chiefly distributed and dispersed within the valley. 5. Seeds of M. rubra, P. thunbergii, and L. acuminata were directly dispersed to the specific topographic areas in which adult trees were distributed and in which juveniles have a predictably high probability of survival relative to random sites.

  15. Bd on the beach: high prevalence of Batrachochytrium dendrobatidis in the lowland forests of Gorgona Island (Colombia, South America).

    PubMed

    Flechas, Sandra Victoria; Sarmiento, Carolina; Amézquita, Adolfo

    2012-09-01

    The amphibian chytrid fungus, Batrachochytrium dendrobatidis, Bd, has been implicated in the decimation and extinction of many amphibian populations worldwide, especially at mid and high elevations. Recent studies have demonstrated the presence of the pathogen in the lowlands from Australia and Central America. We extend here its elevational range by demonstrating its presence at the sea level, in the lowland forests of Gorgona Island, off the Pacific coast of Colombia. We conducted two field surveys, separated by four years, and diagnosed Bd by performing polymerase chain reactions on swab samples from the skin of five amphibian species. All species, including the Critically Endangered Atelopus elegans, tested positive for the pathogen, with prevalences between 3.9 % in A. elegans (in 2010) and 52 % in Pristimantis achatinus. Clinical signs of chytridiomycosis were not detected in any species. To our knowledge, this is the first report of B. dendrobatidis in tropical lowlands at sea level, where temperatures may exceed optimal growth temperatures of this pathogen. This finding highlights the need to understand the mechanisms allowing the interaction between frogs and pathogen in lowland ecosystems. PMID:22669408

  16. Foliar temperature tolerance of temperate and tropical evergreen rain forest trees of Australia.

    PubMed

    Cunningham, S C; Read, J

    2006-11-01

    Australian rain forests extend from tropical climates in the north to temperate climates in the south, providing an opportunity to investigate physiological responses to temperature of both temperate and tropical species within the same forest type. Eight, rain forest canopy tree species were selected to cover the 33 degrees latitudinal range of rain forests in eastern Australia. Temperature tolerance was measured in 6-year-old plants grown in a common environment, by exposing leaves to a series of high temperatures during late summer and a series of freezing temperatures during midwinter. Damage was evaluated based on chlorophyll fluorescence measurements made 2 h after exposure and by visual assessment of leaf damage made a week after exposure. Leaves of the tropical species were more heat tolerant and less frost tolerant than leaves of the temperate species, which is consistent with their climate distributions. In contrast, the temperature tolerance of the photosynthetic apparatus was unrelated to climate in a species' native habitat. However, the tropical species underwent significant photoinhibition during winter. All species maintained the integrity of the photosynthetic apparatus and avoided tissue damage over a similar span of temperatures (about 60 degrees C), reflecting the similar annual temperature ranges in Australia's temperate and tropical rain forests. Chlorophyll fluorescence measurements and visual assessment of leaf damage provided different estimates of the absolute and relative temperature tolerances of the species, thus emphasizing the importance of a direct assessment of tissue damage for determining a species' temperature tolerance.

  17. Diurnal raptors in the fragmented rain forest of the Sierra Imataca, Venezuela

    USGS Publications Warehouse

    Alvarez, E.; Ellis, D.H.; Smith, D.G.; LaRue, C.T.; Bird, David M.; Varland, Daniel E.; Negro, Juan Jose

    1996-01-01

    The rain forest of the Sierra Imataca in eastern Venezuela has been subjected to extensive deforestation for pastures and agricultural settlements. In the last decade the opening of access roads combined with intensified logging and mining activities have fragmented a significant portion of the remaining forest. We noted local distribution and habitat use for 42 species of diurnal raptors observed in affected areas in this region. We observed some raptors considered as forest interior species and other open country species foraging and roosting in man-made openings inside the forest.

  18. Diurnal raptors in the fragmented rain forest of the Sierra Imataca, Venezuela

    USGS Publications Warehouse

    Alvarez, E.; Ellis, D.H.; Smith, D.G.; LaRue, C.T.

    1994-01-01

    The rain forest of the Sierra Imataca in eastern Venezuela has been subjected to extensive deforestation for pastures and agricultural settlements. In the last decade the opening of access roads combined with intensified logging and mining activities have fragmented a significant portion of the remaining forest. We noted local distribution and habitat use for 40 species of diurnal raptors observed in ten affected areas, including raptors considered as forest interior species and some open country species utilizing the man-made openings inside the forest for roosting and foraging.

  19. Behavioral Ecology of Euglossine Bees of the Atlantic Rain Forest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Before the colonization of Brazil, the Atlantic Forest extended from Rio Grande do Norte to Rio Grande do Sul. As recently as 1832, Charles Darwin described it as "a forest which in the grandeur of all its parts could not be exceeded." It is now highly fragmented and only 8% of its former size, wi...

  20. Low-diversity tropical rain forests: Some possible mechanisms for their existence

    SciTech Connect

    Connell, J.H. ); Lowman, M.D. )

    1989-07-01

    The occurrence and characteristics of low-diversity forests are described, and compared with high-diversity ones and some hypotheses about possible mechanisms for their existence are discussed. The author suggest that after a single (EM) ectomycorrhizal tree species achieves dominance in a type-I forest, other species in the same family are more likely to invade than are those of a different family. Thus, a many-species (VAM) vesicular-arbuscular mycorrhizal rain forest might gradually shift to one with a single EM species dominant, leading to a forest of higher diversity dominated by several species from a few families that associate with EM fungi (e.g., as found in dipterocarp forests in southeastern Asia). The latter forests should tend to maintain their diversity because, like VAM forests, EM species in the same family may be nearly equivalent in competitive ability.

  1. Nutrient leaching losses in lowland forests converted to oil palm and rubber plantations in Sumatra, Indonesia

    NASA Astrophysics Data System (ADS)

    Kurniawan, Syahrul; Corre, Marife D.; Rahayu Utami, Sri; Veldkamp, Edzo

    2015-04-01

    In the last two decades, Sumatra, Indonesia is experiencing rapid expansion of oil palm and rubber plantations by conversion of rainforest. This is evident from the 2.9 thousand km2 decrease in forest area in this region over the last 15 years. Such rapid land-use change necessitates assessment of its environmental impacts. Our study was aimed to assess the impact of forest conversion to oil palm and rubber plantations on nutrient leaching losses. Land-use conversion increases nutrient leaching losses due to changes in vegetation litter input, rooting depth, nutrient cycling and management (e.g. fertilization) practices. Our study area was in Jambi Province, Sumatra, Indonesia. We selected two soil landscapes in this region: loam and clay Acrisol soils. At each soil landscape, we investigated four land-use systems: lowland secondary rainforest, secondary forest with regenerating rubber (referred here as jungle rubber), rubber (7-17 years old) and oil palm plantations (9-16 years old). Each land use in each soil landscape was represented by four sites as replicates, totaling to 32 sites. We measured leaching losses using suction lysimeters installed at 1.5-m soil depth, which was well below the rooting depth, with bi-weekly to monthly sampling from February to December 2013. In general, the loam Acrisol landscape, particularly the forest and oil palm plantations, had lower soil solution pH and higher leaching fluxes of dissolved organic N, Na, Ca, Mg, total Al, total S and Cl than the clay Acrisol of the same land uses (all P ≤ 0.05). Among land uses in the loam Acrisol landscape, oil palm had lower soil solution pH and higher leaching fluxes of NH4+, NO3-, dissolved organic C, total P, total S and Cl than rubber plantation whereas forest and jungle rubber showed intermediate fluxes (all P ≤ 0.05, except P ≤ 0.09 for total P); oil palm had also higher Na, Ca, Mg and total Al leaching fluxes than all the other land uses (all P ≤ 0.05, except P ≤ 0.09 for Na

  2. Deforestation history of the eastern rain forests of Madagascar from satellite images

    SciTech Connect

    Green, G.M.; Sussman, R.W. )

    1990-04-13

    Madagascar is biologically one of the richest areas on Earth, and its plants and animals are among the most endangered. Satellite images and vegetation maps based on earlier aerial photographs were used to determine the extent of eastern rain forests in Madagascar and to monitor the rate of deforestation over a 35-year period. In 1985, 3.8 million hectares of rain forest remained, representing only 50% of the 7.6 million hectares existing in 1950 and 34% of the estimated original extent (11.2 million hectares). Between 1950 and 1985, the rate of deforestation averaged 111,000 hectares per year. Deforestation was most rapid in areas with low topographic relief and high population density. If cutting of forests continues at the same pace, only forests on the steepest slopes will survive the next 35 years.

  3. Tracing the Sources of Atmospheric Phosphorus Deposition to a Tropical Rain Forest in Panama Using Stable Oxygen Isotopes.

    PubMed

    Gross, A; Turner, B L; Goren, T; Berry, A; Angert, A

    2016-02-01

    Atmospheric dust deposition can be a significant source of phosphorus (P) in some tropical forests, so information on the origins and solubility of atmospheric P is needed to understand and predict patterns of forest productivity under future climate scenarios. We characterized atmospheric dust P across a seasonal cycle in a tropical lowland rain forest on Barro Colorado Nature Monument (BCNM), Republic of Panama. We traced P sources by combining remote sensing imagery with the first measurements of stable oxygen isotopes in soluble inorganic phosphate (δ(18)OP) in dust. In addition, we measured soluble inorganic and organic P concentrations in fine (<1 μm) and coarse (>1 μm) aerosol fractions and used this data to estimate the contribution of P inputs from dust deposition to the forest P budget. Aerosol dry mass was greater in the dry season (December to April, 5.6-15.7 μg m(-3)) than the wet season (May to November, 3.1-7.1 μg m(-3)). In contrast, soluble P concentrations in the aerosols were lower in the dry season (980-1880 μg P g(-1)) than the wet season (1170-3380 μg P g(-1)). The δ(18)OP of dry-season aerosols resembled that of nearby forest soils (∼19.5‰), suggesting a local origin. In the wet season, when the Trans-Atlantic Saharan dust belt moves north close to Panama, the δ(18)OP of aerosols was considerably lower (∼15.5‰), suggesting a significant contribution of long-distance dust P transport. Using satellite retrieved aerosol optical depth (AOD) and the P concentrations in aerosols we sampled in periods when Saharan dust was evident we estimate that the monthly P input from long distance dust transport during the period with highest Saharan dust deposition is 88 ± 31 g P ha(-1) month(-1), equivalent to between 10 and 29% of the P in monthly litter fall in nearby forests. These findings have important implications for our understanding of modern nutrient budgets and the productivity of tropical forests in the region under future

  4. Tracing the Sources of Atmospheric Phosphorus Deposition to a Tropical Rain Forest in Panama Using Stable Oxygen Isotopes.

    PubMed

    Gross, A; Turner, B L; Goren, T; Berry, A; Angert, A

    2016-02-01

    Atmospheric dust deposition can be a significant source of phosphorus (P) in some tropical forests, so information on the origins and solubility of atmospheric P is needed to understand and predict patterns of forest productivity under future climate scenarios. We characterized atmospheric dust P across a seasonal cycle in a tropical lowland rain forest on Barro Colorado Nature Monument (BCNM), Republic of Panama. We traced P sources by combining remote sensing imagery with the first measurements of stable oxygen isotopes in soluble inorganic phosphate (δ(18)OP) in dust. In addition, we measured soluble inorganic and organic P concentrations in fine (<1 μm) and coarse (>1 μm) aerosol fractions and used this data to estimate the contribution of P inputs from dust deposition to the forest P budget. Aerosol dry mass was greater in the dry season (December to April, 5.6-15.7 μg m(-3)) than the wet season (May to November, 3.1-7.1 μg m(-3)). In contrast, soluble P concentrations in the aerosols were lower in the dry season (980-1880 μg P g(-1)) than the wet season (1170-3380 μg P g(-1)). The δ(18)OP of dry-season aerosols resembled that of nearby forest soils (∼19.5‰), suggesting a local origin. In the wet season, when the Trans-Atlantic Saharan dust belt moves north close to Panama, the δ(18)OP of aerosols was considerably lower (∼15.5‰), suggesting a significant contribution of long-distance dust P transport. Using satellite retrieved aerosol optical depth (AOD) and the P concentrations in aerosols we sampled in periods when Saharan dust was evident we estimate that the monthly P input from long distance dust transport during the period with highest Saharan dust deposition is 88 ± 31 g P ha(-1) month(-1), equivalent to between 10 and 29% of the P in monthly litter fall in nearby forests. These findings have important implications for our understanding of modern nutrient budgets and the productivity of tropical forests in the region under future

  5. Prolonged acid rain facilitates soil organic carbon accumulation in a mature forest in Southern China.

    PubMed

    Wu, Jianping; Liang, Guohua; Hui, Dafeng; Deng, Qi; Xiong, Xin; Qiu, Qingyan; Liu, Juxiu; Chu, Guowei; Zhou, Guoyi; Zhang, Deqiang

    2016-02-15

    With the continuing increase in anthropogenic activities, acid rain remains a serious environmental threat, especially in the fast developing areas such as southern China. To detect how prolonged deposition of acid rain would influence soil organic carbon accumulation in mature subtropical forests, we conducted a field experiment with simulated acid rain (SAR) treatments in a monsoon evergreen broadleaf forest at Dinghushan National Nature Reserve in southern China. Four levels of SAR treatments were set by irrigating plants with water of different pH values: CK (the control, local lake water, pH ≈ 4.5), T1 (water pH=4.0), T2 (water pH=3.5), and T3 (water pH=3.0). Results showed reduced pH measurements in the topsoil exposed to simulated acid rains due to soil acidification. Soil respiration, soil microbial biomass and litter decomposition rates were significantly decreased by the SAR treatments. As a result, T3 treatment significantly increased the total organic carbon by 24.5% in the topsoil compared to the control. Furthermore, surface soil became more stable as more recalcitrant organic matter was generated under the SAR treatments. Our results suggest that prolonged acid rain exposure may have the potential to facilitate soil organic carbon accumulation in the subtropical forest in southern China. PMID:26657252

  6. Prolonged acid rain facilitates soil organic carbon accumulation in a mature forest in Southern China.

    PubMed

    Wu, Jianping; Liang, Guohua; Hui, Dafeng; Deng, Qi; Xiong, Xin; Qiu, Qingyan; Liu, Juxiu; Chu, Guowei; Zhou, Guoyi; Zhang, Deqiang

    2016-02-15

    With the continuing increase in anthropogenic activities, acid rain remains a serious environmental threat, especially in the fast developing areas such as southern China. To detect how prolonged deposition of acid rain would influence soil organic carbon accumulation in mature subtropical forests, we conducted a field experiment with simulated acid rain (SAR) treatments in a monsoon evergreen broadleaf forest at Dinghushan National Nature Reserve in southern China. Four levels of SAR treatments were set by irrigating plants with water of different pH values: CK (the control, local lake water, pH ≈ 4.5), T1 (water pH=4.0), T2 (water pH=3.5), and T3 (water pH=3.0). Results showed reduced pH measurements in the topsoil exposed to simulated acid rains due to soil acidification. Soil respiration, soil microbial biomass and litter decomposition rates were significantly decreased by the SAR treatments. As a result, T3 treatment significantly increased the total organic carbon by 24.5% in the topsoil compared to the control. Furthermore, surface soil became more stable as more recalcitrant organic matter was generated under the SAR treatments. Our results suggest that prolonged acid rain exposure may have the potential to facilitate soil organic carbon accumulation in the subtropical forest in southern China.

  7. Differences in seed rain composition in small and large fragments in the northeast Brazilian Atlantic Forest.

    PubMed

    Knörr, U C; Gottsberger, G

    2012-09-01

    Tropical forests are seriously threatened by fragmentation and habitat loss. The impact of fragment size and forest configuration on the composition of seed rain is insufficiently studied. For the present study, seed rain composition of small and large forest fragments (8-388 ha) was assessed in order to identify variations in seed abundance, species richness, seed size and dispersal mode. Seed rain was documented during a 1-year period in three large and four small Atlantic Forest fragments that are isolated by a sugarcane matrix. Total seed rain included 20,518 seeds of 149 species of trees, shrubs, palms, lianas and herbs. Most species and seeds were animal-dispersed. A significant difference in the proportion of seeds and species within different categories of seed size was found between small and large fragments. Small fragments received significantly more very small-sized seeds (<0.3 cm) and less large-seeded species (>1.5 cm) that were generally very rare, with only one species in small and eight in large fragments. We found a negative correlation between the inflow of small-sized seeds and the percentage of forest cover. Species richness was lower in small than in large fragments, but the difference was not very pronounced. Given our results, we propose changing plant species pools through logging, tree mortality and a high inflow of pioneer species and lianas, especially in small forest fragments and areas with low forest cover. Connecting forest fragments through corridors and reforestation with local large-seeded tree species may facilitate the maintenance of species diversity.

  8. Differences in seed rain composition in small and large fragments in the northeast Brazilian Atlantic Forest.

    PubMed

    Knörr, U C; Gottsberger, G

    2012-09-01

    Tropical forests are seriously threatened by fragmentation and habitat loss. The impact of fragment size and forest configuration on the composition of seed rain is insufficiently studied. For the present study, seed rain composition of small and large forest fragments (8-388 ha) was assessed in order to identify variations in seed abundance, species richness, seed size and dispersal mode. Seed rain was documented during a 1-year period in three large and four small Atlantic Forest fragments that are isolated by a sugarcane matrix. Total seed rain included 20,518 seeds of 149 species of trees, shrubs, palms, lianas and herbs. Most species and seeds were animal-dispersed. A significant difference in the proportion of seeds and species within different categories of seed size was found between small and large fragments. Small fragments received significantly more very small-sized seeds (<0.3 cm) and less large-seeded species (>1.5 cm) that were generally very rare, with only one species in small and eight in large fragments. We found a negative correlation between the inflow of small-sized seeds and the percentage of forest cover. Species richness was lower in small than in large fragments, but the difference was not very pronounced. Given our results, we propose changing plant species pools through logging, tree mortality and a high inflow of pioneer species and lianas, especially in small forest fragments and areas with low forest cover. Connecting forest fragments through corridors and reforestation with local large-seeded tree species may facilitate the maintenance of species diversity. PMID:22372687

  9. Below- and above-ground controls on tree water use in lowland tropical forests

    NASA Astrophysics Data System (ADS)

    Meinzer, F. C.; Woodruff, D.; McCulloh, K.; Domec, J.

    2012-12-01

    Even in moist tropical forests, fluctuations in soil water availability and atmospheric evaporative demand can constrain tree water use. Our research in three lowland tropical forest sites in Panama over the past two decades has identified a series of tree biophysical and functional traits related to daily and seasonal patterns of uptake, transport and loss of water. Studies combining measurements of sap flow and natural abundance of hydrogen isotopes in soil and xylem water during the dry season show considerable variation in depth of soil water uptake among co-occurring species. Trees able to exploit progressively deeper sources of soil water during the dry season, as indicated by increasingly negative xylem water hydrogen isotope ratios, were also able to maintain constant or even increased rates of water use. Injections of a stable isotope tracer (deuterated water) into tree trunks revealed a considerable range of water transit and residence times among co-occurring, similarly-sized trees. Components of tree hydraulic architecture were also strong determinants of patterns of water use. Sapwood hydraulic capacitance, the amount of water released per unit change in tissue water potential, was a strong predictor of several tree water use and water relations traits, including sap velocity, water residence time, daily maximum branch xylem tension, and the time of day at which stomata began to increasingly restrict transpiration. Among early and late successional species, hydraulic traits such as trunk-to-branch tapering of xylem vessels, branch sap flux, branch sapwood specific conductivity and whole-tree leaf area-specific hydraulic conductance scaled uniformly with branch wood density. Consistent with differences in trunk-to-branch tapering of vessels between early and late successional species, the ratio of branch to trunk sap flux was substantially greater in early successional species. Among species, stomatal conductance and transpiration per unit leaf area

  10. Effects of canopy tree species on belowground biogeochemistry in a lowland wet tropical forest

    USGS Publications Warehouse

    Keller, Adrienne B.; Reed, Sasha C.; Townsend, Alan R.; Cleveland, Cory C.

    2013-01-01

    Tropical rain forests are known for their high biological diversity, but the effects of plant diversity on important ecosystem processes in this biome remain unclear. Interspecies differences in both the demand for nutrients and in foliar and litter nutrient concentrations could drive variations in both the pool sizes and fluxes of important belowground resources, yet our understanding of the effects and importance of aboveground heterogeneity on belowground biogeochemistry is poor, especially in the species-rich forests of the wet tropics. To investigate the effects of individual tree species on belowground biogeochemical processes, we used both field and laboratory studies to examine how carbon (C), nitrogen (N), and phosphorus (P) cycles vary under nine different canopy tree species – including three legume and six non-legume species – that vary in foliar nutrient concentrations in a wet tropical forest in southwestern Costa Rica. We found significant differences in belowground C, N and P cycling under different canopy tree species: total C, N and P pools in standing litter varied by species, as did total soil and microbial C and N pools. Rates of soil extracellular acid phosphatase activity also varied significantly among species and functional groups, with higher rates of phosphatase activity under legumes. In addition, across all tree species, phosphatase activity was significantly positively correlated with litter N/P ratios, suggesting a tight coupling between relative N and P inputs and resource allocation to P acquisition. Overall, our results suggest the importance of aboveground plant community composition in promoting belowground biogeochemical heterogeneity at relatively small spatial scales.

  11. Primary forest dynamics in lowland dipterocarp forest at Danum Valley, Sabah, Malaysia, and the role of the understorey.

    PubMed

    Newbery, D M; Kennedy, D N; Petol, G H; Madani, L; Ridsdale, C E

    1999-11-29

    Changes in species composition in two 4-ha plots of lowland dipterocarp rainforest at Danum, Sabah, were measured over ten years (1986-1996) for trees > or = 10 cm girth at breast height (gbh). Each included a lower-slope to ridge gradient. The period lay between two drought events of moderate intensity but the forest showed no large lasting responses, suggesting that its species were well adapted to this regime. Mortality and recruitment rates were not unusual in global or regional comparisons. The forest continued to aggrade from its relatively (for Sabah) low basal area in 1986 and, together with the very open upper canopy structure and an abundance of lianas, this suggests a forest in a late stage of recovery from a major disturbance, yet one continually affected by smaller recent setbacks. Mortality and recruitment rates were not related to population size in 1986, but across subplots recruitment was positively correlated with the density and basal area of small trees (10-< 50cm gbh) forming the dense understorey. Neither rate was related to topography. While species with larger mean gbh had greater relative growth rates (rgr) than smaller ones, subplot mean recruitment rates were correlated with rgr among small trees. Separating understorey species (typically the Euphorbiaceae) from the overstorey (Dipterocarpaceae) showed marked differences in change in mortality with increasing gbh: in the former it increased, in the latter it decreased. Forest processes are centred on this understorey quasi-stratum. The two replicate plots showed a high correspondence in the mortality, recruitment, population changes and growth rates of small trees for the 49 most abundant species in common to both. Overstorey species had higher rgrs than understorey ones, but both showed considerable ranges in mortality and recruitment rates. The supposed trade-off in traits, viz slower rgr, shade tolerance and lower population turnover in the understorey group versus faster potential

  12. Data Quality of the JERS-1 SAR Global Rain Forest Mapping (GRFM) Project

    NASA Technical Reports Server (NTRS)

    Chapman, B.; Alves, M.; Shimada, M.; Freeman, T.; Rosenqvist, A.; Siqueira, P.

    1998-01-01

    The National Space Development Agency of Japan's (NASDA) JERS-1 SAR began collecting data in 1995 for the Global Rain Forest Mapping Project (GRFM). The GRFM data quality has been examined for products resulting from both the NASDA and Alaska SAR facility's (ASF) processing facilities.

  13. Disturbance regimes, gap-demanding trees and seed mass related to tree height in warm temperate rain forests worldwide.

    PubMed

    Grubb, Peter J; Bellingham, Peter J; Kohyama, Takashi S; Piper, Frida I; Valido, Alfredo

    2013-08-01

    For tropical lowland rain forests, Denslow (1987) hypothesized that in areas with large-scale disturbances tree species with a high demand for light make up a larger proportion of the flora; results of tests have been inconsistent. There has been no test for warm temperate rain forests (WTRFs), but they offer a promising testing ground because they differ widely in the extent of disturbance. WTRF is dominated by microphylls sensu Raunkiaer and has a simpler structure and range of physiognomy than tropical or subtropical rain forests. It occurs in six parts of the world: eastern Asia, New Zealand, Chile, South Africa, SE Australia and the Azores. On the Azores it has been mostly destroyed, so we studied instead the subtropical montane rain forest (STMRF) on the Canary Islands which also represents a relict of the kind of WTRF that once stretched across southern Eurasia. We sought to find whether in these six regions the proportion of tree species needing canopy gaps for establishment reflects the frequency and/or extent of canopy disturbance by wind, landslide, volcanic eruptions (lava flow and ash fall), flood or fire. We used standard floras and ecological accounts to draw up lists of core tree species commonly reaching 5 m height. We excluded species which are very rare, very localized in distribution, or confined to special habitats, e.g. coastal forests or rocky sites. We used published accounts and our own experience to classify species into three groups: (1) needing canopy gaps for establishment; (2) needing either light shade throughout or a canopy gap relatively soon (a few months or years) after establishment; and (3) variously more shade-tolerant. Group 1 species were divided according the kind of canopy opening needed: tree-fall gap, landslide, lava flow, flood or fire. Only some of the significant differences in proportion of Group 1 species were consistent with differences in the extent of disturbance; even in some of those cases other factors seem

  14. Disturbance regimes, gap-demanding trees and seed mass related to tree height in warm temperate rain forests worldwide.

    PubMed

    Grubb, Peter J; Bellingham, Peter J; Kohyama, Takashi S; Piper, Frida I; Valido, Alfredo

    2013-08-01

    For tropical lowland rain forests, Denslow (1987) hypothesized that in areas with large-scale disturbances tree species with a high demand for light make up a larger proportion of the flora; results of tests have been inconsistent. There has been no test for warm temperate rain forests (WTRFs), but they offer a promising testing ground because they differ widely in the extent of disturbance. WTRF is dominated by microphylls sensu Raunkiaer and has a simpler structure and range of physiognomy than tropical or subtropical rain forests. It occurs in six parts of the world: eastern Asia, New Zealand, Chile, South Africa, SE Australia and the Azores. On the Azores it has been mostly destroyed, so we studied instead the subtropical montane rain forest (STMRF) on the Canary Islands which also represents a relict of the kind of WTRF that once stretched across southern Eurasia. We sought to find whether in these six regions the proportion of tree species needing canopy gaps for establishment reflects the frequency and/or extent of canopy disturbance by wind, landslide, volcanic eruptions (lava flow and ash fall), flood or fire. We used standard floras and ecological accounts to draw up lists of core tree species commonly reaching 5 m height. We excluded species which are very rare, very localized in distribution, or confined to special habitats, e.g. coastal forests or rocky sites. We used published accounts and our own experience to classify species into three groups: (1) needing canopy gaps for establishment; (2) needing either light shade throughout or a canopy gap relatively soon (a few months or years) after establishment; and (3) variously more shade-tolerant. Group 1 species were divided according the kind of canopy opening needed: tree-fall gap, landslide, lava flow, flood or fire. Only some of the significant differences in proportion of Group 1 species were consistent with differences in the extent of disturbance; even in some of those cases other factors seem

  15. Effects of simulated acid rain on glucose mineralization and some physicochemical properties of forest soils

    SciTech Connect

    Strayer, R.F.; Alexander, M.

    1981-10-01

    To study the effects of acid rain, samples of forest soils were exposed to a continuous application of 100 cm of simulated acid rain (pH 3.2-4.1) at 5 cm/hour, or to intermittent 1-hour applications of 5 cm of simulated acid rain three times per week for 7 weeks. The major effects of the simulated acid rain were localized at the top of the soil and included lower pH values and glucose mineralization rates, and higher exchangeable Al and total and exchange acidity. The acidity penetrated further in the more acid soils. The mineralization of /sup 14/C-glucose was measured at concentrations of 1.5-54 ..mu..g glucose/g of soil. Glucose mineralization in the test soils (pH values of 4.4-7.1) was inhibited by the continuous exposure to simulated acid rain at pH 3.2 but not a pH 4.1. The extent of inhibition depended on the soil and the initial glucose concentration. Exposure of one soil to 7 weeks of intermittent applications of simulated acid rain at pH 3.2 reduced the mineralization rate at the three glucose concentrations tested. These data suggest that acid rain may have a significant impact on microbial activity.

  16. Effect of simulated acid rain on nitrification and nitrogen mineralization in forest soils

    SciTech Connect

    Strayer, R.F.; Lin, C.J.; Alexander, M.

    1981-01-01

    To determine the possible microbiological changes in soil resulting from acid rain, columns containing samples of forest soils were leached with either a continuous application of 100cm of simulated acid rain (pH3.2-4.1) at 5 cm/hour or an intermittent 1.5-hour application of 1.2 cm of simulated acid rain twice weekly for 19 weeks. The upper 1.0- to 1.5-cm portions of soil from treated columns were used to determine the changes in inorganic N levels in the soil. Nitrification of added ammonium (NH4(+)) was inhibited following continuous exposure of soil to simulated acid rain of pH 4.1-3.2. The extent of the inhibition was directly related to the acidity of the simulated rain solutions. The production of inorganic N in the absence of added NH(+) was either stimulated or unaffected following continuous treatment of soils with pH 3.2 simulated acid rain. The addition of nitrapyrine, an inhibitor of autotrophic nitrification, caused a decrease in nitrification in water-treated soil but had little effect on nitrification in soil treated with pH 3.2 simulated acid rain.

  17. How does tree age influence damage and recovery in forests impacted by freezing rain and snow?

    PubMed

    Zhu, LiRong; Zhou, Ting; Chen, BaoMing; Peng, ShaoLin

    2015-05-01

    The response and recovery mechanisms of forests to damage from freezing rain and snow events are a key topic in forest research and management. However, the relationship between the degree of damage and tree age, i.e., whether seedlings, young trees, or adult trees are most vulnerable, remains unclear and is rarely reported. We investigated the effect of tree age on the degrees of vegetation damage and subsequent recovery in three subtropical forest types-coniferous, mixed, and broad-leaved-in the Tianjing Mountains, South China, after a series of rare icy rain and freezing snow events in 2008. The results showed that damage and recovery rates were both dependent on tree age, with the proportion of damaged vegetation increasing with age (estimated by diameter at breast height, DBH) in all three forest types and gradually plateauing. Significant variation occurred among forest types. Young trees in the coniferous forest were more vulnerable than those in the broad-leaved forest. The type of damage also varied with tree age in different ways in the three forest types. The proportion of young seedlings that were uprooted (the most severe type of damage) was highest in the coniferous forest. In the mixed forest, young trees were significantly more likely to be uprooted than seedlings and adult trees, while in the broad-leaved forest, the proportion of uprooted adult trees was significantly higher than that of seedlings and young trees. There were also differences among forest types in how tree age affected damage recovery. In the coniferous forest, the recovery rate of trees with broken trunks or crowns (DBH > 2.5 cm) increased with tree age. However, in the mixed and broad-leaved forests, no obvious correlation between the recovery rate of trees with broken trunks or crowns and tree age was observed. Trees with severe root damage did not recover; they were uprooted and died. In these forests, vegetation damage and recovery showed tree age dependencies, which varied

  18. How does tree age influence damage and recovery in forests impacted by freezing rain and snow?

    PubMed

    Zhu, LiRong; Zhou, Ting; Chen, BaoMing; Peng, ShaoLin

    2015-05-01

    The response and recovery mechanisms of forests to damage from freezing rain and snow events are a key topic in forest research and management. However, the relationship between the degree of damage and tree age, i.e., whether seedlings, young trees, or adult trees are most vulnerable, remains unclear and is rarely reported. We investigated the effect of tree age on the degrees of vegetation damage and subsequent recovery in three subtropical forest types-coniferous, mixed, and broad-leaved-in the Tianjing Mountains, South China, after a series of rare icy rain and freezing snow events in 2008. The results showed that damage and recovery rates were both dependent on tree age, with the proportion of damaged vegetation increasing with age (estimated by diameter at breast height, DBH) in all three forest types and gradually plateauing. Significant variation occurred among forest types. Young trees in the coniferous forest were more vulnerable than those in the broad-leaved forest. The type of damage also varied with tree age in different ways in the three forest types. The proportion of young seedlings that were uprooted (the most severe type of damage) was highest in the coniferous forest. In the mixed forest, young trees were significantly more likely to be uprooted than seedlings and adult trees, while in the broad-leaved forest, the proportion of uprooted adult trees was significantly higher than that of seedlings and young trees. There were also differences among forest types in how tree age affected damage recovery. In the coniferous forest, the recovery rate of trees with broken trunks or crowns (DBH > 2.5 cm) increased with tree age. However, in the mixed and broad-leaved forests, no obvious correlation between the recovery rate of trees with broken trunks or crowns and tree age was observed. Trees with severe root damage did not recover; they were uprooted and died. In these forests, vegetation damage and recovery showed tree age dependencies, which varied

  19. Geomorphology Drives Amphibian Beta Diversity in Atlantic Forest Lowlands of Southeastern Brazil

    PubMed Central

    Luiz, Amom Mendes; Leão-Pires, Thiago Augusto; Sawaya, Ricardo J.

    2016-01-01

    Beta diversity patterns are the outcome of multiple processes operating at different scales. Amphibian assemblages seem to be affected by contemporary climate and dispersal-based processes. However, historical processes involved in present patterns of beta diversity remain poorly understood. We assess and disentangle geomorphological, climatic and spatial drivers of amphibian beta diversity in coastal lowlands of the Atlantic Forest, southeastern Brazil. We tested the hypothesis that geomorphological factors are more important in structuring anuran beta diversity than climatic and spatial factors. We obtained species composition via field survey (N = 766 individuals), museum specimens (N = 9,730) and literature records (N = 4,763). Sampling area was divided in four spatially explicit geomorphological units, representing historical predictors. Climatic descriptors were represented by the first two axis of a Principal Component Analysis. Spatial predictors in different spatial scales were described by Moran Eigenvector Maps. Redundancy Analysis was implemented to partition the explained variation of species composition by geomorphological, climatic and spatial predictors. Moreover, spatial autocorrelation analyses were used to test neutral theory predictions. Beta diversity was spatially structured in broader scales. Shared fraction between climatic and geomorphological variables was an important predictor of species composition (13%), as well as broad scale spatial predictors (13%). However, geomorphological variables alone were the most important predictor of beta diversity (42%). Historical factors related to geomorphology must have played a crucial role in structuring amphibian beta diversity. The complex relationships between geomorphological history and climatic gradients generated by the Serra do Mar Precambrian basements were also important. We highlight the importance of combining spatially explicit historical and contemporary predictors for understanding

  20. Geomorphology Drives Amphibian Beta Diversity in Atlantic Forest Lowlands of Southeastern Brazil.

    PubMed

    Luiz, Amom Mendes; Leão-Pires, Thiago Augusto; Sawaya, Ricardo J

    2016-01-01

    Beta diversity patterns are the outcome of multiple processes operating at different scales. Amphibian assemblages seem to be affected by contemporary climate and dispersal-based processes. However, historical processes involved in present patterns of beta diversity remain poorly understood. We assess and disentangle geomorphological, climatic and spatial drivers of amphibian beta diversity in coastal lowlands of the Atlantic Forest, southeastern Brazil. We tested the hypothesis that geomorphological factors are more important in structuring anuran beta diversity than climatic and spatial factors. We obtained species composition via field survey (N = 766 individuals), museum specimens (N = 9,730) and literature records (N = 4,763). Sampling area was divided in four spatially explicit geomorphological units, representing historical predictors. Climatic descriptors were represented by the first two axis of a Principal Component Analysis. Spatial predictors in different spatial scales were described by Moran Eigenvector Maps. Redundancy Analysis was implemented to partition the explained variation of species composition by geomorphological, climatic and spatial predictors. Moreover, spatial autocorrelation analyses were used to test neutral theory predictions. Beta diversity was spatially structured in broader scales. Shared fraction between climatic and geomorphological variables was an important predictor of species composition (13%), as well as broad scale spatial predictors (13%). However, geomorphological variables alone were the most important predictor of beta diversity (42%). Historical factors related to geomorphology must have played a crucial role in structuring amphibian beta diversity. The complex relationships between geomorphological history and climatic gradients generated by the Serra do Mar Precambrian basements were also important. We highlight the importance of combining spatially explicit historical and contemporary predictors for understanding

  1. Geomorphology Drives Amphibian Beta Diversity in Atlantic Forest Lowlands of Southeastern Brazil.

    PubMed

    Luiz, Amom Mendes; Leão-Pires, Thiago Augusto; Sawaya, Ricardo J

    2016-01-01

    Beta diversity patterns are the outcome of multiple processes operating at different scales. Amphibian assemblages seem to be affected by contemporary climate and dispersal-based processes. However, historical processes involved in present patterns of beta diversity remain poorly understood. We assess and disentangle geomorphological, climatic and spatial drivers of amphibian beta diversity in coastal lowlands of the Atlantic Forest, southeastern Brazil. We tested the hypothesis that geomorphological factors are more important in structuring anuran beta diversity than climatic and spatial factors. We obtained species composition via field survey (N = 766 individuals), museum specimens (N = 9,730) and literature records (N = 4,763). Sampling area was divided in four spatially explicit geomorphological units, representing historical predictors. Climatic descriptors were represented by the first two axis of a Principal Component Analysis. Spatial predictors in different spatial scales were described by Moran Eigenvector Maps. Redundancy Analysis was implemented to partition the explained variation of species composition by geomorphological, climatic and spatial predictors. Moreover, spatial autocorrelation analyses were used to test neutral theory predictions. Beta diversity was spatially structured in broader scales. Shared fraction between climatic and geomorphological variables was an important predictor of species composition (13%), as well as broad scale spatial predictors (13%). However, geomorphological variables alone were the most important predictor of beta diversity (42%). Historical factors related to geomorphology must have played a crucial role in structuring amphibian beta diversity. The complex relationships between geomorphological history and climatic gradients generated by the Serra do Mar Precambrian basements were also important. We highlight the importance of combining spatially explicit historical and contemporary predictors for understanding

  2. Economic incentives for rain forest conservation across scales.

    PubMed

    Kremen, C; Niles, J O; Dalton, M G; Daily, G C; Ehrlich, P R; Fay, J P; Grewal, D; Guillery, R P

    2000-06-01

    Globally, tropical deforestation releases 20 to 30% of anthropogenic greenhouse gases. Conserving forests could reduce emissions, but the cost-effectiveness of this mechanism for mitigation depends on the associated opportunity costs. We estimated these costs from local, national, and global perspectives using a case study from Madagascar. Conservation generated significant benefits over logging and agriculture locally and globally. Nationally, however, financial benefits from industrial logging were larger than conservation benefits. Such differing economic signals across scales may exacerbate tropical deforestation. The Kyoto Protocol could potentially overcome this obstacle to conservation by creating markets for protection of tropical forests to mitigate climate change.

  3. [Effect of acid rain on mercury leaching from forest yellow soil in Jinyun Mountain].

    PubMed

    Li, Jing; Wei, Shiqiang; Yang, Xuechun

    2004-09-01

    Forest yellow soil and arable yellow soil in Jinyun Mountain were collected to study the effect of simulated acid rain(adjusted to pH 2.0, 3.0, 4.0 and 5.0) on the Hg leaching from soils by the methods of static extraction and dynamic leaching. The results showed that in forest yellow soils, surface accumulation of Hg occurred, and the accumulated Hg was easier to be leached out than that in arable yellow soil by acid rain. The amount of leached Hg was the largest at pH 4.0. To abate the risk of Hg pollution in water bodies by the Hg leaching from this forest soil, the Mountain should be closed, and timber-felling should be forbidden.

  4. Effects of acid rain on forest nutrient status

    SciTech Connect

    Johnson, D.W.; Turner, J.; Kelly, J.M.

    1982-06-01

    The paper presents an extensive literature review that deals with the assessment of the effects of acidic atmospheric inputs on forest nutrient status within the context of natural, internal acid production by carbonic and organic acids as well as the nutrient inputs and drains by management practices such as harvesting, fire and fertilization. 123 refs.

  5. Primary seed shadow generated by gibbons in the rain forests of Barito Ulu, central Borneo.

    PubMed

    McConkey, K R

    2000-09-01

    Gibbons are one of the main frugivores in the forests of Southeast Asia, and consequently have long been considered to be good seed dispersers. This is the first study in which the primary seed shadow they create by their ranging and foraging activities is evaluated in detail. I studied two gibbon groups over 12 months in lowland dipterocarp forest in central Borneo. The gibbons dispersed up to 81% of the species they consumed and destroyed the seeds of only 12%. Fruit with elongated seeds (up to 20 mm wide) were more likely to be dispersed than round seeds. Considering that the survival rate of seeds in the forest to one year was 8%, the gibbons effectively dispersed 13 seedlings ha(-1) group(-1) year(-1). Their effect on germination was very variable, although most species did eventually germinate. Most seeds were deposited along their major ranging routes and close to or under feeding trees. PMID:10993135

  6. Amazon Rain Forest Classification Using J-ERS-1 SAR Data

    NASA Technical Reports Server (NTRS)

    Freeman, A.; Kramer, C.; Alves, M.; Chapman, B.

    1994-01-01

    The Amazon rain forest is a region of the earth that is undergoing rapid change. Man-made disturbance, such as clear cutting for agriculture or mining, is altering the rain forest ecosystem. For many parts of the rain forest, seasonal changes from the wet to the dry season are also significant. Changes in the seasonal cycle of flooding and draining can cause significant alterations in the forest ecosystem.Because much of the Amazon basin is regularly covered by thick clouds, optical and infrared coverage from the LANDSAT and SPOT satellites is sporadic. Imaging radar offers a much better potential for regular monitoring of changes in this region. In particular, the J-ERS-1 satellite carries an L-band HH SAR system, which via an on-board tape recorder, can collect data from almost anywhere on the globe at any time of year.In this paper, we show how J-ERS-1 radar images can be used to accurately classify different forest types (i.e., forest, hill forest, flooded forest), disturbed areas such as clear cuts and urban areas, and river courses in the Amazon basin. J-ERS-1 data has also shown significant differences between the dry and wet season, indicating a strong potential for monitoring seasonal change. The algorithm used to classify J-ERS-1 data is a standard maximum-likelihood classifier, using the radar image local mean and standard deviation of texture as input. Rivers and clear cuts are detected using edge detection and region-growing algorithms. Since this classifier is intended to operate successfully on data taken over the entire Amazon, several options are available to enable the user to modify the algorithm to suit a particular image.

  7. Effects of acid rain on mycorrhizal infection and N cycling in forest soils

    SciTech Connect

    Stroo, H.F.

    1986-01-01

    Increasing the acidity of simulated rain from pH 5.6 to 3.0 reduced the number of mycorrhizal roots on white pine seedlings by 20% after 16 weeks of exposure. Mycorrhizal infection of red oaks was 25% less at a rain pH of 3.5 than at pH 5.6. Simulated acid rain also caused increases in the N contents, net photosynthesis, and growth of seedlings, as well as decreases in root:shoot ratios and in the concentration of sucrose in the roots. To measure the effects of acid rain on N mineralization, nitrification, and total inorganic N, columns containing samples from the surface horizons of 12 forest soils were exposed to simulated rain at 3 times ambient deposition rates for 16 weeks. The effects on N mineralization varied between soils, with the greatest inhibitions being observed in soils with low organic matter contents. The apparent protection by organic matter was associated with an increase in short-term buffering capacity. The average amount of N mineralized after exposure was not significantly affected by rain pH. Similarly, nitrification was inhibited during exposure to simulated rain at pH 3.5, but was unaffected after exposure. Enrichments from an acid forest soil failed to show the presence of autotrophic nitrifiers, and the effects of temperature and selective inhibitors indicated that fungi were primarily responsible for nitrification in this soil. A fungus capable of heterotrophic nitrification at pH 4.0 was isolated and identified as Absidia cylindrospora Hagem.

  8. Rainfall estimates for hydrological models: Comparing rain gauge, radar and microwave link data as input for the Wageningen Lowland Runoff Simulator (WALRUS)

    NASA Astrophysics Data System (ADS)

    Brauer, Claudia; Overeem, Aart; Uijlenhoet, Remko

    2015-04-01

    Several rainfall measurement techniques are available for hydrological applications, each with its own spatial and temporal resolution. We investigated the effect of differences in rainfall estimates on discharge simulations in a lowland catchment by forcing a novel rainfall-runoff model (WALRUS) with rainfall data from gauges, radars and microwave links. The hydrological model used for this analysis is the recently developed Wageningen Lowland Runoff Simulator (WALRUS). WALRUS is a rainfall-runoff model accounting for hydrological processes relevant to areas with shallow groundwater (e.g. groundwater-surface water feedback). Here, we used WALRUS for case studies in the Hupsel Brook catchment. We used two automatic rain gauges with hourly resolution, located inside the catchment (the base run) and 30 km northeast. Operational (real-time) and climatological (gauge-adjusted) C-band radar products and country-wide rainfall maps derived from microwave link data from a cellular telecommunication network were also used. Discharges simulated with these different inputs were compared to observations. Traditionally, the precipitation research community places emphasis on quantifying spatial errors and uncertainty, but for hydrological applications, temporal errors and uncertainty should be quantified as well. Its memory makes the hydrologic system sensitive to missed or badly timed rainfall events, but also emphasizes the effect of a bias in rainfall estimates. Systematic underestimation of rainfall by the uncorrected operational radar product leads to very dry model states and an increasing underestimation of discharge. Using the rain gauge 30 km northeast of the catchment yields good results for climatological studies, but not for forecasting individual floods. Simulating discharge using the maps derived from microwave link data and the gauge-adjusted radar product yields good results for both events and climatological studies. This indicates that these products can be

  9. Fine-Scale Vertical Stratification and Guild Composition of Saproxylic Beetles in Lowland and Montane Forests: Similar Patterns despite Low Faunal Overlap

    PubMed Central

    Weiss, Matthias; Procházka, Jiří; Schlaghamerský, Jiří; Cizek, Lukas

    2016-01-01

    Objective The finer scale patterns of arthropod vertical stratification in forests are rarely studied and poorly understood. Further, there are no studies investigating whether and how altitude affects arthropod vertical stratification in temperate forests. We therefore investigated the fine-scale vertical stratification of diversity and guild structure of saproxylic beetles in temperate lowland and montane forests and compared the resulting patterns between the two habitats. Methods The beetles were sampled with flight intercept traps arranged into vertical transects (sampling heights 0.4, 1.2, 7, 14, and 21 m). A triplet of such transects was installed in each of the five sites in the lowland and in the mountains; 75 traps were used in each forest type. Results 381 species were collected in the lowlands and 236 species in the mountains. Only 105 species (21%) were found at both habitats; in the montane forest as well as in the lowlands, the species richness peaked at 1.2 m, and the change in assemblage composition was most rapid near the ground. The assemblages clearly differed between the understorey (0.4 m, 1.2 m) and the canopy (7 m, 14 m, 21 m) and between the two sampling heights within the understorey, but less within the canopy. The stratification was better pronounced in the lowland, where canopy assemblages were richer than those near the forest floor (0.4 m). In the mountains the samples from 14 and 21 m were more species poor than those from the lower heights. The guild structure was similar in both habitats. Conclusions The main patterns of vertical stratification and guild composition were strikingly similar between the montane and the lowland forest despite the low overlap of their faunas. The assemblages of saproxylic beetles were most stratified near ground. The comparisons of species richness between canopy and understorey may thus give contrasting results depending on the exact sampling height in the understorey. PMID:26978783

  10. Aboveground Biomass Modeling from Field and LiDAR Data in Brazilian Amazon Tropical Rain Forest

    NASA Astrophysics Data System (ADS)

    Silva, C. A.; Hudak, A. T.; Vierling, L. A.; Keller, M. M.; Klauberg Silva, C. K.

    2015-12-01

    Tropical forests are an important component of global carbon stocks, but tropical forest responses to climate change are not sufficiently studied or understood. Among remote sensing technologies, airborne LiDAR (Light Detection and Ranging) may be best suited for quantifying tropical forest carbon stocks. Our objective was to estimate aboveground biomass (AGB) using airborne LiDAR and field plot data in Brazilian tropical rain forest. Forest attributes such as tree density, diameter at breast height, and heights were measured at a combination of square plots and linear transects (n=82) distributed across six different geographic zones in the Amazon. Using previously published allometric equations, tree AGB was computed and then summed to calculate total AGB at each sample plot. LiDAR-derived canopy structure metrics were also computed at each sample plot, and random forest regression modelling was applied to predict AGB from selected LiDAR metrics. The LiDAR-derived AGB model was assessed using the random forest explained variation, adjusted coefficient of determination (Adj. R²), root mean square error (RMSE, both absolute and relative) and BIAS (both absolute and relative). Our findings showed that the 99th percentile of height and height skewness were the best LiDAR metrics for AGB prediction. The AGB model using these two best predictors explained 59.59% of AGB variation, with an Adj. R² of 0.92, RMSE of 33.37 Mg/ha (20.28%), and bias of -0.69 (-0.42%). This study showed that LiDAR canopy structure metrics can be used to predict AGC stocks in Tropical Forest with acceptable precision and accuracy. Therefore, we conclude that there is good potential to monitor carbon sequestration in Brazilian Tropical Rain Forest using airborne LiDAR data, large field plots, and the random forest algorithm.

  11. Effect of simulated acid rain on nitrification and nitrogen mineralization in forest soils

    SciTech Connect

    Strayer, R.F.; Lin, C.J.; Alexander, M.

    1981-10-01

    To determine the possible microbiological changes in soil resulting from acid rain, columns containing samples of forest soils were leached with either a continuous application of 100 cm of simulated acid rain (pH 3.2-4.1) at 5 cm/hour or an intermittent 1.5-hour application of 1.2 cm of simulated acid rain twice weekly for 19 weeks. The upper 1.0- to 1.5-cm portions of soil from treated columns were used to determine the changes in inorganic N levels in the soil. Nitrification of added ammonium (NH/sub 4//sup +/) was inhibited following continuous exposure of soil to simulated acid rain of pH 4.1-3.2. The extent of the inhibition was directly related to the acidity of the simulated rain solutions. The production of inorganic N in the absence of added NH/sub 4//sup +/ was either stimulated or unaffected following continuous treatment of soils with pH 3.2 simulated acid rain. The addition of nitrapyrin (2-chloro-6-(trichloromethyl)pyridine), an inhibitor of autotrophic nitrification, caused a decrease in nitrification in water-treated soil but had little effect on nitrification in soil treated with pH 3.2 simulated acid rain. Intermittent applications of simulated acid rain (pH 3.5-4.1) for 19 weeks partially inhibited nitrate (NO/sub 3//sup -/) production in soil amended with NH/sub 4//sup +/ following the exposure period, but NO/sub 3//sup -/ production in unamended soil was either unaffected or stimulated.

  12. Land-use systems and resilience of tropical rain forests in the Tehuantepec Isthmus, Mexico.

    PubMed

    García-Romero, Arturo; Oropeza-Orozco, Oralia; Galicia-Sarmiento, Leopoldo

    2004-12-01

    Land-cover types were analyzed for 1970, 1990 and 2000 as the bases for determining land-use systems and their influence on the resilience of tropical rain forests in the Tehuantepec Isthmus, Mexico. Deforestation (DR) and mean annual transformation rates were calculated from land-cover change data; thus, the classification of land-use change processes was determined according to their impact on resilience: a) Modification, including land-cover conservation and intensification, and b) Conversion, including disturbance and regeneration processes. Regeneration processes, from secondary vegetation under extensive use, cultivated vegetation under intensive use, and cultivated or induced vegetation under extensive use to mature or secondary vegetation, have high resilience capacity. In contrast, cattle-raising is characterized by rapid expansion, long-lasting change, and intense damages; thus, recent disturbance processes, which include the conversion to cattle-raising, provoke the downfall of the traditional agricultural system, and nullify the capacity of resilience of tropical rain forest. The land-use cover change processes reveal a) the existence of four land-use systems (forestry, extensive agriculture, extensive cattle-raising, and intensive uses) and b) a trend towards the replacement of agricultural and forestry systems by extensive cattle-raising, which was consolidated during 1990-2000 (DR of evergreen tropical rain forest = 4.6%). Only the forestry system, which is not subject to deforestation, but is affected by factors such as selective timber, extraction, firewood collection, grazing, or human-induced fire, is considered to have high resilience (2 years), compared to agriculture (2-10 years) or cattle-raising (nonresilient). It is concluded that the analysis of land-use systems is essential for understanding the implications of land-use cover dynamics on forest recovery and land degradation in tropical rain forests.

  13. Tropical rain forest conversion to pasture: Changes in vegetation and soil properties

    SciTech Connect

    Reiners, W.A. ); Bouwman, A.F. ); Parsons, W.F.J. Institute of Marine and Coastal Sciences, Rugers Univ., New Brunswick, NJ ); Keller, M. )

    1994-05-01

    The effect of converting lowland tropical rainforest to pasture, and of subsequent succession of pasture lands to secondary forest, were examined in the Atlantic Zone of Costa Rica. Three replicate sites of each of four land-use types representing this disturbance-recovery sequence were sampled for changes in vegetation, pedological properties, and potential nitrogen mineralization and nitrification. The four land-use types included primary forest, actively grazed pasture (10-36 yr old), abandoned pasture (abandoned 4-10 yr) and secondary forest (abandoned 10-20 yr). Conversion and succession had obvious and significant effects on canopy cover, canopy height, species composition, and species richness; it appeared that succession of secondary forests was proceeding toward a floristic composition like that of the primary forests. Significant changes in soil properties associated with conversion of forest to pasture included: (1) a decrease in acidity and increase in some base exchange properties, (2) and increase in bulk density and a concomitant decrease in porosity, (3) higher concentrations of NH[sub 4][sup +], (4) lower concentrations of NO[sub 3][sup [minus

  14. Modern pollen-rain characteristics of tall terra firme moist evergreen forest, southern Amazonia

    NASA Astrophysics Data System (ADS)

    Gosling, William D.; Mayle, Francis E.; Tate, Nicholas J.; Killeen, Timothy J.

    2005-11-01

    The paucity of modern pollen-rain data from Amazonia constitutes a significant barrier to understanding the Late Quaternary vegetation history of this globally important tropical forest region. Here, we present the first modern pollen-rain data for tall terra firme moist evergreen Amazon forest, collected between 1999 and 2001 from artificial pollen traps within a 500 × 20 m permanent study plot (14°34'50″S, 60°49'48″W) in Noel Kempff Mercado National Park (NE Bolivia). Spearman's rank correlations were performed to assess the extent of spatial and inter-annual variability in the pollen rain, whilst statistically distinctive taxa were identified using Principal Components Analysis (PCA). Comparisons with the floristic and basal area data of the plot (stems ≥10 cm d.b.h.) enabled the degree to which taxa are over/under-represented in the pollen rain to be assessed (using R-rel values). Moraceae/Urticaceae dominates the pollen rain (64% median abundance) and is also an important constituent of the vegetation, accounting for 16% of stems ≥10 cm d.b.h. and ca. 11% of the total basal area. Other important pollen taxa are Arecaceae (cf. Euterpe), Melastomataceae/Combretaceae, Cecropia, Didymopanax, Celtis, and Alchornea. However, 75% of stems and 67% of the total basal area of the plot ≥10 cm d.b.h. belong to species which are unidentified in the pollen rain, the most important of which are Phenakospermum guianensis (a banana-like herb) and the key canopy-emergent trees, Erisma uncinatum and Qualea paraensis.

  15. Richness and Abundance of Ichneumonidae in a Fragmented Tropical Rain Forest.

    PubMed

    Ruiz-Guerra, B; Hanson, P; Guevara, R; Dirzo, R

    2013-10-01

    Because of the magnitude of land use currently occurring in tropical regions, the local loss of animal species due to habitat fragmentation has been widely studied, particularly in the case of vertebrates. Many invertebrate groups and the ichneumonid wasps in particular, however, have been poorly studied in this context, despite the fact that they are one of the most species-rich groups and play an important role as regulators of other insect populations. Here, we recorded the taxonomic composition of ichneumonid parasitoids and assessed their species richness, abundance, similarity, and dominance in the Los Tuxtlas tropical rain forest, Mexico. We compared two forest types: a continuous forest (640 ha) and a forest fragment (19 ha). We sampled ichneumonids using four malaise traps in both forest types during the dry (September-October) and rainy (March-April) seasons. A total of 104 individuals of Ichneumonidae belonging to 11 subfamilies, 18 genera, and 42 species were collected in the continuous forest and 11 subfamilies, 15 genera, and 24 species were collected in the forest fragment. Species richness, abundance, and diversity of ichneumonids were greater in the continuous forest than in the forest fragment. We did not detect differences between seasons. Species rank/abundance curves showed that the ichneumonid community between the forest types was different. Species similarity between forest types was low. The most dominant species in continuous forest was Neotheronia sp., whereas in the forest fragment, it was Orthocentrus sp. Changes in the ichneumonid wasp community may compromise important tropical ecosystem processes.

  16. A direct test of nitrogen and phosphorus limitation to net primary productivity in a lowland tropical wet forest.

    PubMed

    Alvarez-Clare, S; Mack, M C; Brooks, M

    2013-07-01

    Experimental evidence for limitation of net primary productivity (NPP) by nitrogen (N) or phosphorus (P) in lowland tropical forests is rare, and the results from the few existing studies have been inconclusive. To directly test if N or P limit NPP in a lowland tropical wet forest in Costa Rica, we conducted a full factorial fertilization experiment (4 treatments x 6 replicates in 30 x 30 m plots). We focused on the influence of tree size and taxa on nutrient limitation, because in these forests a wide variety of tree functional traits related to nutrient acquisition and use are likely to regulate biogeochemical processes. After 2.7 years, a higher percentage of trees per plot increased basal area (BA) with P additions (66.45% +/- 3.28% without P vs. 76.88% +/- 3.28% with P), but there were no other community-level responses to N or P additions on BA increase, litterfall productivity, or root growth. Phosphorus additions resulted in doubled stem growth rates in small trees (5-10 cm diameter at breast height (dbh); [P < or = 0.01]) but had no effect on intermediate (10-30 cm dbh) or large trees (> 30 cm dbh). Phosphorus additions also increased the percentage of seedling survival from 59% to 78% (P < 0.01), as well as the percentage of seedlings that grew (P = 0.03), and increased leaf number (P = 0.02). Trees from Pentaclethra macroloba, the most abundant species, did not increase growth rates with fertilization (P = 0.40). In contrast, the most abundant palms (Socratea exorrhiza) had more than two times higher stem growth rates with P additions (P = 0.01). Our experiment reiterates that P availability is a significant driver of plant processes in these systems, but highlights the importance of considering different aspects of the plant community when making predictions concerning nutrient limitation. We postulate that in diverse, lowland tropical forests "heterogeneous nutrient limitation" occurs, not only driven by variability in nutrient responses among taxa

  17. Rain forest promotes trophic interactions and diversity of trap-nesting Hymenoptera in adjacent agroforestry.

    PubMed

    Klein, Alexandra-Maria; Steffan-Dewenter, Ingolf; Tscharntke, Teja

    2006-03-01

    1. Human alteration of natural ecosystems to agroecosystems continues to accelerate in tropical countries. The resulting world-wide decline of rain forest causes a mosaic landscape, comprising simple and complex agroecosystems and patchily distributed rain forest fragments of different quality. Landscape context and agricultural management can be expected to affect both species diversity and ecosystem services by trophic interactions. 2. In Central Sulawesi, Indonesia, 24 agroforestry systems, differing in the distance to the nearest natural forest (0-1415 m), light intensity (37.5-899.6 W/m(-2)) and number of vascular plant species (7-40 species) were studied. Ten standardized trap nests for bees and wasps, made from reed and knotweed internodes, were exposed in each study site. Occupied nests were collected every month, over a period totalling 15 months. 3. A total of 13,617 brood cells were reared to produce adults of 14 trap-nesting species and 25 natural enemy species, which were mostly parasitoids. The total number of species was affected negatively by increasing distance from forest and increased with light intensity of agroforestry systems. The parasitoids in particular appeared to benefit from nearby forests. Over a 500-m distance, the number of parasitoid species decreased from eight to five, and parasitism rates from 12% to 4%. 4. The results show that diversity and parasitism, as a higher trophic interaction and ecosystem service, are enhanced by (i) improved connectivity of agroecosystems with natural habitats such as agroforestry adjacent to rain forest and (ii) management practices to increase light availability in agroforestry, which also enhances richness of flowering plants in the understorey.

  18. The biological diversity conservation district: A rain forest conservation tool for the future

    SciTech Connect

    Simons, M.

    1995-12-01

    Over the next twenty years, the Earth`s rain forests may decrease by forty percent! This paper presents a revolutionary corporate entity for the protection of those forests, the biological diversity conservation district (biodistricts). The underlying cause of rain forest destruction is unfettered competition for limited resources. The competitors are many: farmers, business, local and national governments, the biotechnology and ecotourism industries, multinational companies, public utilities, and indigenous groups. To varying degrees, all compete within the marketplace. biodistricts will bring together two forces once thought to be antithetical: conservation an development. They will be set up in corporate form, owned and controlled by groups claiming access to the forest resources. Because the various groups will fight for the same resources habitats, ecosystems, and genetic diversity-each will prevent the others from destroying them. The district members will ensure that all businesses maintain sustainable development practices because the economic success of the district depends upon the area`s natural beauty and biological diversity. This paper analyzes the effects on the culture, politics, economy and conservation there. It will conclude that the comprehensive approach taken by biodistricts is the only method for solving the problem of rain forest destruction; that it is economically feasible, culturally viable, and ethically defensible. By March 1, 1995, the paper will represent not only the culmination of eighteen months of research, writing and interviews regarding biological diversity conservation, but also the impetus to push the thinking of environmentalists and business persons in a new direction, perhaps the only direction that will allow the nations of the world to protect their forests for the next twenty years and beyond.

  19. Ozone measurements in the troposphere of an Amazonian rain forest environment

    NASA Technical Reports Server (NTRS)

    Kirchhoff, V. W. J. H.; Browell, E. V.; Gregory, G. L.

    1988-01-01

    Ozone concentration profiles from the ground to above the stratospheric peak were obtained in an equatorial rain forest environment near Manaus in the Amazon Basin between July and August of 1985. The peak ozone concentration (4.4 x 10 to the 22 molecules/cu cm) was found at 20 mbar (26.6 km). A major pollution (biomass-burning) event which occurred near the end of the experiment was responsible for large changes in ozone concentration.

  20. PAR (photosynthetically active radiation) conversion efficiencies of a tropical rain forest

    SciTech Connect

    Luxmoore, R.J.; Saldarriaga, J.G.

    1988-01-01

    The mean annual quantities of photosynthetically active radiation (PAR) absorbed during various stage of regeneration of a tropical rain forest in the upper Rio Negro region of Colombia and Venezuela were estimated for the intervals between clearcut and 1, 3, 10, 20, 35, 60, 80, and 200 years of growth. The forest phytomass and litterfall at each storage were from previous studies, and the data were used to calculate the mean annual quantity of net dry matter production per unit of absorbed PAR, the PAR conversion efficiency. 7 refs., 2 figs., 1 tab.

  1. Degraded tropical rain forests possess valuable carbon storage opportunities in a complex, forested landscape.

    PubMed

    Alamgir, Mohammed; Campbell, Mason J; Turton, Stephen M; Pert, Petina L; Edwards, Will; Laurance, William F

    2016-07-20

    Tropical forests are major contributors to the terrestrial global carbon pool, but this pool is being reduced via deforestation and forest degradation. Relatively few studies have assessed carbon storage in degraded tropical forests. We sampled 37,000 m(2) of intact rainforest, degraded rainforest and sclerophyll forest across the greater Wet Tropics bioregion of northeast Australia. We compared aboveground biomass and carbon storage of the three forest types, and the effects of forest structural attributes and environmental factors that influence carbon storage. Some degraded forests were found to store much less aboveground carbon than intact rainforests, whereas others sites had similar carbon storage to primary forest. Sclerophyll forests had lower carbon storage, comparable to the most heavily degraded rainforests. Our findings indicate that under certain situations, degraded forest may store as much carbon as intact rainforests. Strategic rehabilitation of degraded forests could enhance regional carbon storage and have positive benefits for tropical biodiversity.

  2. Degraded tropical rain forests possess valuable carbon storage opportunities in a complex, forested landscape.

    PubMed

    Alamgir, Mohammed; Campbell, Mason J; Turton, Stephen M; Pert, Petina L; Edwards, Will; Laurance, William F

    2016-01-01

    Tropical forests are major contributors to the terrestrial global carbon pool, but this pool is being reduced via deforestation and forest degradation. Relatively few studies have assessed carbon storage in degraded tropical forests. We sampled 37,000 m(2) of intact rainforest, degraded rainforest and sclerophyll forest across the greater Wet Tropics bioregion of northeast Australia. We compared aboveground biomass and carbon storage of the three forest types, and the effects of forest structural attributes and environmental factors that influence carbon storage. Some degraded forests were found to store much less aboveground carbon than intact rainforests, whereas others sites had similar carbon storage to primary forest. Sclerophyll forests had lower carbon storage, comparable to the most heavily degraded rainforests. Our findings indicate that under certain situations, degraded forest may store as much carbon as intact rainforests. Strategic rehabilitation of degraded forests could enhance regional carbon storage and have positive benefits for tropical biodiversity. PMID:27435389

  3. Degraded tropical rain forests possess valuable carbon storage opportunities in a complex, forested landscape

    NASA Astrophysics Data System (ADS)

    Alamgir, Mohammed; Campbell, Mason J.; Turton, Stephen M.; Pert, Petina L.; Edwards, Will; Laurance, William F.

    2016-07-01

    Tropical forests are major contributors to the terrestrial global carbon pool, but this pool is being reduced via deforestation and forest degradation. Relatively few studies have assessed carbon storage in degraded tropical forests. We sampled 37,000 m2 of intact rainforest, degraded rainforest and sclerophyll forest across the greater Wet Tropics bioregion of northeast Australia. We compared aboveground biomass and carbon storage of the three forest types, and the effects of forest structural attributes and environmental factors that influence carbon storage. Some degraded forests were found to store much less aboveground carbon than intact rainforests, whereas others sites had similar carbon storage to primary forest. Sclerophyll forests had lower carbon storage, comparable to the most heavily degraded rainforests. Our findings indicate that under certain situations, degraded forest may store as much carbon as intact rainforests. Strategic rehabilitation of degraded forests could enhance regional carbon storage and have positive benefits for tropical biodiversity.

  4. Degraded tropical rain forests possess valuable carbon storage opportunities in a complex, forested landscape

    PubMed Central

    Alamgir, Mohammed; Campbell, Mason J.; Turton, Stephen M.; Pert, Petina L.; Edwards, Will; Laurance, William F.

    2016-01-01

    Tropical forests are major contributors to the terrestrial global carbon pool, but this pool is being reduced via deforestation and forest degradation. Relatively few studies have assessed carbon storage in degraded tropical forests. We sampled 37,000 m2 of intact rainforest, degraded rainforest and sclerophyll forest across the greater Wet Tropics bioregion of northeast Australia. We compared aboveground biomass and carbon storage of the three forest types, and the effects of forest structural attributes and environmental factors that influence carbon storage. Some degraded forests were found to store much less aboveground carbon than intact rainforests, whereas others sites had similar carbon storage to primary forest. Sclerophyll forests had lower carbon storage, comparable to the most heavily degraded rainforests. Our findings indicate that under certain situations, degraded forest may store as much carbon as intact rainforests. Strategic rehabilitation of degraded forests could enhance regional carbon storage and have positive benefits for tropical biodiversity. PMID:27435389

  5. Pervasive canopy dynamics produce short-term stability in a tropical rain forest landscape.

    PubMed

    Kellner, James R; Clark, David B; Hubbell, Stephen P

    2009-02-01

    A fundamental property of all forest landscapes is the size frequency distribution of canopy gap disturbances. But characterizing forest structure and changes at large spatial scales has been challenging and most of our understanding is from permanent inventory plots. Here we report the first application of light detection and ranging remote sensing to measurements of canopy disturbance and regeneration in an old-growth tropical rain forest landscape. Pervasive local height changes figure prominently in the dynamics of this forest. Although most canopy gaps recruited to higher positions during 8.5 years, size frequency distributions were similar at two points in time and well-predicted by power-laws. At larger spatial scales (hundreds of ha), height increases and decreases occurred with similar frequency and changes to canopy height that were analysed using a height transition matrix suggest that the distribution of canopy height at the beginning of the study was close to the projected steady-state equilibrium under the recent disturbance regime. Taken together, these findings show how widespread local height changes can produce short-term stability in a tropical rain forest landscape.

  6. Brazilian rain forest security - environment - development. Study project report

    SciTech Connect

    Arruda, P.A.

    1993-03-25

    The Amazon region has been intensely discussed in the recent years. Most of these discussions have been highly influenced by interests groups. To understand the Amazon area we need to specify what the Amazon is, to describe the forest, to evaluate its mineral and biological resources, and to study the people living in the region. A security analysis reveals that there are no main threats to Brazilian Amazon. Nevertheless, narco guerrillas, acting in neighboring countries, can cross the borders and challenge regional authorities. First World interests may disturb Brazilian policies to the region. To face these threats, Brazilian armed forces maintain a well trained military sharing with other native people the security and the routes towards progress. Brazilian government is also implementing some programs to achieve a well balanced development. The new concepts of sustainable development are applied to keep the region's natural resources available for future generations. Among these programs this paper addresses the ecological economic zoning, Calha Norte Program and Amazon Protection System (SIPAM/SIVAM). In synthesis it demonstrates the Brazilian commitment to integrate, develop and preserve this rich and exotic region.

  7. Precipitation signal in pollen rain from tropical forests, South India.

    PubMed

    Barboni, D; Bonnefille, R

    2001-04-01

    We have analyzed the pollen content of 51 surface soil samples collected in tropical evergreen and deciduous forests from the Western Ghats of South India sampled along a west to east gradient of decreasing rainfall (between 11 degrees 30-13 degrees 20'N and 75 degrees 30-76 degrees 30'E). Values of mean annual precipitation (Pann, mm/yr) have been calculated at each of the 51 sampling sites from a great number of meteorological stations in South India, using a method of data interpolation based on artificial neural network. Interpolated values at the pollen sites of Pann range from 1200 to 5555mm/yr, while mean temperature of the coldest month (MTCO) remains >15 degrees C and humidity factor (AET/PET, the actual evapotranspiration to potential evapotranspiration ratio) remains also included between 65 and 72%.Results are presented in the form of percentage pollen diagrams where samples are arranged according to increasing values of annual precipitation. They indicate that the climatic signal of rainfall is clearly evidenced by distinct pollen associations. Numerical analyses show that annual precipitation is an important parameter explaining the modern distribution of pollen taxa in this region. Pollen taxa markers of high rainfall (Pann >2500mm/yr) are Mallotus type, Elaeocarpus, Syzygium type, Olea dioica, Gnetum ula, and Hopea type, associated with Ixora type and Caryota. Pollen taxa markers of low rainfall (Pann <2500mm/yr) are Melastomataceae/Combretaceae, Maytenus type, Lagerstroemia and Grewia. The proportions of evergreen taxa and of arboreal taxa vary according to rainfall values. Indeed, when rainfall is <2500mm/yr, percentage of arboreal pollen (AP) is <50% and proportion of evergreen taxa is <20%. When rainfall exceeds 2500mm/yr, AP values average 70%, and proportion of evergreen taxa increases from 60 to 90%. Moreover, a good correlation between precipitation and proportion of evergreen taxa (0.85) presumes that precipitation can be estimated from

  8. Within community patch dynamics in a tropical montane rain forest of Hainan Island, South China

    NASA Astrophysics Data System (ADS)

    Zang, Runguo; Tao, Jianping; Li, Chunyang

    2005-07-01

    According to the forest-growth-cycle theory, forest communities are dynamic, mosaic systems composed of patches in different developmental phases. Based on an investigation in a sample of tropical montane rain forest of Hainan Island in South China, four distinct growth phases or patch types were recognized and patterns of patch mosaics and changes in tree species diversity were studied. Diurnal changes in light and temperature regimes in different patch types of the forest growth cycle were measured and analysed. Our results were as follows: (1) The percentages of different patch types within the sampled forest community were for the gap phase 38.5%, building phase 28.5%, mature phase 27.0% and degenerate phase 6.0%; (2) The change of densities (number of individuals/ha) of trees in the forest growth cycle was mainly caused by the larger sized trees; (3) The changes of species diversity with the forest growth cycle showed a humpback pattern; (4) The average DBH, average height, average basal area at DBH, and average volume of each individual and stand volume all increased with the forest cycle process; (5) Tree species richness and tree density at each phase of the forest cycle were positively correlated; (6) The environmental factors changed significantly, both diurnally and with progress of the forest cycle. Light intensity and soil surface temperature changed more in the gap phase than the other three phases. A framework to explain the mechanism for maintaining biological diversity within the tropical montane forest of Hainan Island is described.

  9. [Seed rain, soil seed bank, and natural regeneration of natural Toona ciliata var. pubescens forest].

    PubMed

    Huang, Hong-Lan; Zhang, Lu; Liao, Cheng-Kai

    2012-04-01

    Taking the natural Toona ciliata var. pubescens forest in the Jiujiangshan National Nature Reserve in Jiangxi Province of China as test object, an investigation was conducted on the seed rain, soil seed bank, and seedlings number in 2008-2011. The seed rain of the forest was dispersed from late October to the end of December. In 2010, the seed rain intensity in different sampling plots was in the order of Xiagongtang observatory (320.3 +/- 23.5 seeds x m(-2)) > Xiagongtang protection station (284.7 +/- 24.2 seeds x m(-2)) > Daqiutian protection station (251.6 +/- 24.7 seeds x m(-2)), and the quantity of the intact seeds in soil supplied for seed germination and regeneration was 222.0, 34.3, and 22.6 seeds x m(-2), respectively. The seed bank reserves was affected by the seed production amount, bird feeding, and seed viability, etc., of which, bird feeding was the prime factor for the substantial drop of the seed bank reserves. Due to the low resistance against storage and a large number of rot during storage, the seeds in soil could hardly be effectively stored beyond one month. The seedlings germinated in December were averagely less than 2 stands x m(-2), and the soil seed reserves in the next January was the least (6.7-11.8 seeds x m(-2)), with the germinated seedlings averagely 0.4-0.6 stands x m(-2), which was consistent with the rare distribution of natural seedlings in the forest. It was concluded that the small seed rain reserves, low seed vigor of soil seed bank, and low seedling establishment were the important factors impacting the natural regeneration of T. ciliata var. pubescens.

  10. The influence of mature oak stands and spruce plantations on soil-dwelling click beetles in lowland plantation forests

    PubMed Central

    Loskotová, Tereza

    2016-01-01

    Most European forests have been converted into forest plantations that are managed for timber production. The main goal of this paper was to determine the difference between mature native sessile oak (Quercus petraea) stands and non-indigenous Norway spruce (Picea abies) plantations, with respect to communities of Athous click beetles in approximately 6,500 ha of lowland plantation forest area in the Czech Republic. Athous subfuscus was the most abundant and widespread species, followed by A. zebei and A. haemorrhoidalis, while A. vittatus was considered rare. Spatial analysis of environmental variables inside studied patches showed that the species composition of Athous beetles best responded to a 20 m radius surrounding traps. The species’ responses to the environment showed that A. vittatus and A. haemorrhoidalis preferred oak stands, while A. zebei and A. subfuscus were associated with spruce plantations. In addition, oak stands showed higher diversity of beetle communities. The studied species are important for their ecosystem services (e.g. predation on pests or bioturbation) and seem to tolerate certain degrees of human disturbances, which is especially beneficial for forest plantations managed for timber production. PMID:26793425

  11. Using biodiversity methods to assess the impacts of oil and gas development in tropical rain forests

    SciTech Connect

    Reagan, D.P.; Silva del Poso, X. |

    1995-06-01

    Oil and gas development in tropical rain forests has attracted international attention because of the potentially adverse effects on the forest ecosystems. Biodiversity is a topic of particular concern, but is difficult to assess for small areas of disturbance. In July 1992 we used light traps to compare insect diversity at canopy and ground level as a means of detecting the impacts of an exploratory well site and related facilities within mature Amazonian rain forest in the Oriente Province of Ecuador. Replicate samples were collected at the well site, in a nearby area of agricultural development, and in a reference site within mature forest. Species richness was determined, and diversity indices were calculated for each set of samples. Results indicated that changes in diversity could be detected in the canopy and at ground level at the well site, but that the reduction in diversity was small. Biological diversity was substantially reduced in the area of agricultural development. Limitations and possible applications of this approach are discussed.

  12. Effects of Bromelia pinguin (Bromeliaceae) on soil ecosystem function and fungal diversity in the lowland forests of Costa Rica

    PubMed Central

    2014-01-01

    Background Bromelia pinguin (Bromeliaceae) is a terrestrial bromeliad commonly found under forest stands throughout the Neotropics that has been shown to have antifungal activity in vitro. We have hypothesized that this bromeliad would also have an effect on the fungal populations in nearby soil by decreasing fungaldiversity and negatively impacting C and N cycle-related activities. A previous study in the lowland forest of Costa Rica showed the soil beneath these bromeliads had decreased fungal ITS DNA and differences in C and N levels compared to adjacent primary forest soils. Results In this follow-up study, we found that the bromeliad soils had lower rates of C and N biomass development and lower phenol oxidase activity (suggesting less decreased fungal decomposition activity). The results of T-RFLP and cloning-based taxonomic analyses showed the community level diversity and abundance of fungal ITS DNA was less in bromeliad soils. Sequence analysis of fungal ITS DNA clones showed marked differences in fungal community structure between habitats of Basidiomycota (Tremellales, Agricales, Thelephorales), Ascomycota (Helotiales), and Zycomycota populations. Conclusions The data show there to be differences in the soil nutrient dynamics and fungal community structure and activity associated with these bromeliads, as compared to the adjacent primary forest. This suggests the possibility that the anti-fungal activity of the bromeliad extends into the soil. The bromeliad-dense regions of these primary forest habitats provide a unique natural micro-habitat within the forests and the opportunity to better identify the role of fungal communities in the C and N cycles in tropical soils. PMID:24885984

  13. Height-related changes in leaf photosynthetic traits in diverse Bornean tropical rain forest trees.

    PubMed

    Kenzo, Tanaka; Inoue, Yuta; Yoshimura, Mitsunori; Yamashita, Megumi; Tanaka-Oda, Ayumi; Ichie, Tomoaki

    2015-01-01

    Knowledge of variations in morphophysiological leaf traits with forest height is essential for quantifying carbon and water fluxes from forest ecosystems. Here, we examined changes in leaf traits with forest height in diverse tree species and their role in environmental acclimation in a tropical rain forest in Borneo that does not experience dry spells. Height-related changes in leaf physiological and morphological traits [e.g., maximum photosynthetic rate (Amax), stomatal conductance (gs), dark respiration rate (Rd), carbon isotope ratio (δ(13)C), nitrogen (N) content, and leaf mass per area (LMA)] from understory to emergent trees were investigated in 104 species in 29 families. We found that many leaf area-based physiological traits (e.g., A(max-area), Rd, gs), N, δ(13)C, and LMA increased linearly with tree height, while leaf mass-based physiological traits (e.g., A(max-mass)) only increased slightly. These patterns differed from other biomes such as temperate and tropical dry forests, where trees usually show decreased photosynthetic capacity (e.g., A(max-area), A(max-mass)) with height. Increases in photosynthetic capacity, LMA, and δ(13)C are favored under bright and dry upper canopy conditions with higher photosynthetic productivity and drought tolerance, whereas lower R d and LMA may improve shade tolerance in lower canopy trees. Rapid recovery of leaf midday water potential to theoretical gravity potential during the night supports the idea that the majority of trees do not suffer from strong drought stress. Overall, leaf area-based photosynthetic traits were associated with tree height and the degree of leaf drought stress, even in diverse tropical rain forest trees.

  14. The Influence Of Variability Of Water Resources In Lowland Forests On Selected Parameters Describing The Condition Of Trees

    NASA Astrophysics Data System (ADS)

    Tyszka, Jan; Stolarek, Andrzej; Fronczak, Ewa

    2014-01-01

    The influence of water conditions on the condition and growth of tree stands has been analysed in the context of the climatic and hydrological functions forest plays. Long observational series obtained for precipitation, outflow and depths below the surface of the water table have been put together with measured increases in the breast-height diameters of Scots pines and the severity of crown defoliation observable in selected tree species growing on the Polish Lowland, in order to determine the overall scope to the reaction stand condition manifests in the face of ongoing variability of water conditions within forest. An overall improvement in the condition of stands over the last 20 years does not disguise several-year cyclicity to changes capable of shaping the situation, i.a. departures from long-term mean values for precipitation totals and groundwater levels. The condition of stands is seen to worsen in both dry and wet years. Analysis of the degree to which pine, spruce and broadleaved stands experience defoliation points to spruce stands responding most to extreme hydro-climatic conditions. Extreme situations as regards water resources were seen to involve a response over two-year time intervals in the case of coniferous stands. Unsurprisingly, optimal growing-season (June-September) precipitation totals correspond with long-term average figures, while being slightly higher for spruce (at 384 mm), than for Scots pine or broadleaved species (375 mm). The relationships reported gain confirmation in analysis of periodic change in breast-height diameter increments characterising Scots pines, whose growth is seen to depend closely, not only on precipitation, but also above all on the depth of the water table in the summer half-year. Optimal depths of the water table proved to be different, being around 20 cm below ground in the case of marshy coniferous forest, 80 cm in wet habitats, and 135 cm in fresh habitats. Depending on the possibilities for water to soak

  15. Atmospheric salt deposition in a tropical mountain rain forest at the eastern Andean slopes of South Ecuador - Pacific or Atlantic origin?

    NASA Astrophysics Data System (ADS)

    Makowski Giannoni, S.; Trachte, K.; Rollenbeck, R.; Lehnert, L.; Fuchs, J.; Bendix, J.

    2015-10-01

    Salt (NaCl) is recently proven to be of highest importance for ecosystem functioning of the Amazon lowland forests because of its importance for herbivory, litter decomposition and thus, carbon cycling. Salt deposition should generally decline with distance from its marine sources. For tropical South America, a negative east-west salt availability gradient is assumed in the Amazon as a consequence of the barrier effect of the Andes for Pacific air masses. However, this generalized pattern may not hold for the tropical mountain rain forest in the Andes of southern Ecuador. To analyze salt availability, we investigate the deposition of Na+ and Cl- which are good proxies of sea spray aerosol. Because of the complexity of the terrain and related cloud and rain formation processes, salt deposition was analyzed from both, rain and occult precipitation (OP) water along an altitudinal gradient over a period from 2004 to 2009. To assess the influence of Atlantic and Pacific air masses on the locally observed deposition of sodium and chloride, sea-salt aerosol concentration data from the Monitoring Atmospheric Composition and Climate (MACC) reanalysis dataset and back-trajectory statistical methods were combined. Our results based on deposition time series and 2192 generated trajectories show a clear difference in the temporal variation of sodium and chloride concentration due to height and exposure to winds. The sea-salt transport was highly seasonal where higher locations revealed a stronger seasonality. Although the influence of the easterlies were predominant regarding atmospheric circulation, the statistical analysis of trajectories and hybrid receptor models revealed a stronger impact of the Pacific sea-salt sources on the deposition at the study area. The highest concentration in rain and cloud water was found between September and February originating from both, the equatorial Pacific and Atlantic. However, the Pacific sources contributed with up to 25 % to the

  16. The impact of rain on ice nuclei populations at a forested site in Colorado

    NASA Astrophysics Data System (ADS)

    Prenni, A. J.; Tobo, Y.; Garcia, E.; Demott, P. J.; Huffman, J. A.; McCluskey, C. S.; Kreidenweis, S. M.; Prenni, J. E.; PöHlker, C.; PöSchl, U.

    2013-01-01

    It has long been known that precipitation can impact atmospheric aerosol, altering number concentrations and size-dependent composition. Such effects result from competing mechanisms: precipitation can remove particles through wet deposition, or precipitation can lead to the emission of particles through mechanical ejection, biological processes, or re-suspension from associated wind gusts. These particles can feed back into the hydrologic cycle by serving as cloud nuclei. In this study, we investigated how precipitation at a forested site impacted the concentration and composition of ice nuclei (IN). We show that ground level IN concentrations were enhanced during rain events, with concentrations increasing by up to a factor of 40 during rain. We also show that a fraction of these IN were biological, with some of the IN identified using DNA sequencing. As these particles get entrained into the outflow of the storm, they may ultimately reach cloud levels, impacting precipitation of subsequent storms.

  17. Vegetation and fire in lowland dry forest at Wa’ahila Ridge on O’ahu, Hawai’i

    PubMed Central

    Lu, Pei-Luen; DeLay, John K.

    2016-01-01

    Abstract Long-term ecological studies are critical for providing key insights in ecology, environmental change, natural resource management and biodiversity conservation. However, island fire ecology is poorly understood. No previous studies are available that analyze vegetative changes in burned and unburned dry forest remnants on Wa’ahila Ridge, Hawai’i. This study investigates vegetation succession from 2008 to 2015, following a fire in 2007 which caused significant differences in species richness, plant density, and the frequency of woody, herb, grass, and lichens between burned and unburned sites. These findings infer that introduced plants have better competitive ability to occupy open canopy lands than native plants after fire. This study also illustrates the essential management need to prevent alien plant invasion, and to restore the native vegetation in lowland areas of the Hawaiian Islands by removing invasive species out-planting native plants after fire.

  18. Vegetation and fire in lowland dry forest at Wa’ahila Ridge on O’ahu, Hawai’i

    PubMed Central

    Lu, Pei-Luen; DeLay, John K.

    2016-01-01

    Abstract Long-term ecological studies are critical for providing key insights in ecology, environmental change, natural resource management and biodiversity conservation. However, island fire ecology is poorly understood. No previous studies are available that analyze vegetative changes in burned and unburned dry forest remnants on Wa’ahila Ridge, Hawai’i. This study investigates vegetation succession from 2008 to 2015, following a fire in 2007 which caused significant differences in species richness, plant density, and the frequency of woody, herb, grass, and lichens between burned and unburned sites. These findings infer that introduced plants have better competitive ability to occupy open canopy lands than native plants after fire. This study also illustrates the essential management need to prevent alien plant invasion, and to restore the native vegetation in lowland areas of the Hawaiian Islands by removing invasive species out-planting native plants after fire. PMID:27698574

  19. Replacing rubber plantations by rain forest in Southwest China--who would gain and how much?

    PubMed

    Ahlheim, Michael; Börger, Tobias; Frör, Oliver

    2015-02-01

    The cultivation of rubber trees in Xishuangbanna Prefecture in China's Yunnan Province has triggered an unprecedented economic development but it is also associated with severe environmental problems. Rubber plantations are encroaching the indigenous rain forests at a large scale and a high speed in Xishuangbanna. Many rare plant and animal species are endangered by this development, the natural water management is disturbed, and even the microclimate in this region has changed over the past years. The present study aims at an assessment of the environmental benefits accruing from a reforestation project partly reversing the deforestation that has taken place over the past years. To this end, a Contingent Valuation survey has been conducted in Xishuangbanna to elicit local residents' willingness to pay for this reforestation program that converts existing rubber plantations back into forest. It is shown that local people's awareness of the environmental problems caused by increasing rubber plantation is quite high and that in spite of the economic advantages of rubber plantation there is a positive willingness among the local population to contribute financially to a reduction of existing rubber plantations for the sake of a partial restoration of the local rain forest. These results could be used for the practical implementation of a Payments for Eco-System Services system for reforestation in Xishuangbanna.

  20. Bibliography on tropical rain forests and the global carbon cycle: Volume 1, An introduction to the literature

    SciTech Connect

    Hall, C.A.S.; Brown, S.; O'Hara, F.M. Jr.; Bogdonoff, P.B.; Barshaw, D.; Kaufman, E.; Underhill, S.

    1988-05-01

    This bibliography covers the world literature on tropical rain forests, tropical deforestation, land-use change in the tropics, tropical forest conversion, and swidden agriculture as related to the global carbon cycle. Historic papers and books are included, but comprehensive coverage was only sought for 1980 through 1987. This compendium of nearly 2000 entries forms the point of departure for a series of bibliographies on this topic. Other works in this series will be on the global carbon cycle and rain forests in specific geographic areas, whereas this volume includes references to literature about the global carbon cycle and rain forests anywhere in the world. The bibliography is ordered alphabetically by author and is indexed by subject and author.

  1. Detection of large above-ground biomass variability in lowland forest ecosystems by airborne LiDAR

    NASA Astrophysics Data System (ADS)

    Jubanski, J.; Ballhorn, U.; Kronseder, K.; Franke, J.; Siegert, F.

    2013-06-01

    Quantification of tropical forest above-ground biomass (AGB) over large areas as input for Reduced Emissions from Deforestation and forest Degradation (REDD+) projects and climate change models is challenging. This is the first study which attempts to estimate AGB and its variability across large areas of tropical lowland forests in Central Kalimantan (Indonesia) through correlating airborne light detection and ranging (LiDAR) to forest inventory data. Two LiDAR height metrics were analysed, and regression models could be improved through the use of LiDAR point densities as input (R2 = 0.88; n = 52). Surveying with a LiDAR point density per square metre of about 4 resulted in the best cost / benefit ratio. We estimated AGB for 600 km of LiDAR tracks and showed that there exists a considerable variability of up to 140% within the same forest type due to varying environmental conditions. Impact from logging operations and the associated AGB losses dating back more than 10 yr could be assessed by LiDAR but not by multispectral satellite imagery. Comparison with a Landsat classification for a 1 million ha study area where AGB values were based on site-specific field inventory data, regional literature estimates, and default values by the Intergovernmental Panel on Climate Change (IPCC) showed an overestimation of 43%, 102%, and 137%, respectively. The results show that AGB overestimation may lead to wrong greenhouse gas (GHG) emission estimates due to deforestation in climate models. For REDD+ projects this leads to inaccurate carbon stock estimates and consequently to significantly wrong REDD+ based compensation payments.

  2. Diaspore bank of bryophytes in tropical rain forests: the importance of breeding system, phylum and microhabitat.

    PubMed

    Maciel-Silva, Adaíses S; Válio, Ivany Ferraz Marques; Rydin, Håkan

    2012-02-01

    Diaspore banks are crucial for the maintenance and resilience of plant communities, but diaspore banks of bryophytes remain poorly known, especially from tropical ecosystems. This is the first study to focus on the role of diaspore banks of bryophytes in tropical rain forests. Our aim was to test whether microhabitat (substrate type) and species traits (breeding system, phylum) are important in explaining the diaspore bank composition. Using samples cultivated in the laboratory, we assessed the number of species and shoots emerging from bark, decaying wood and soil from two sites of the Atlantic rain forest (montane and sea level) in Brazil by comparing the contribution of species by phylum (mosses, liverworts) and breeding system (monoicous, dioicous). More species emerged from bark (68) and decaying wood (55) than from soil (22). Similar numbers of species were found at both sites. Mosses were more numerous in terms of number of species and shoots, and monoicous species dominated over dioicous species. Substrate pH had only weak effects on shoot emergence. Species commonly producing sporophytes and gemmae had a high contribution to the diaspore banks. These superficial diaspore banks represented the extant vegetation rather well, but held more monoicous species (probably short-lived species) compared to dioicous ones. We propose that diaspore bank dynamics are driven by species traits and microhabitat characteristics, and that short-term diaspore banks of bryophytes in tropical rain forests contribute to fast (re)establishment of species after disturbances and during succession, particularly dioicous mosses investing in asexual reproduction and monoicous mosses investing in sexual reproduction.

  3. Interplay between Amazonia Tropical Rain Forest Fires (Mesoscale distribution) and global carbon cycle

    NASA Astrophysics Data System (ADS)

    Cordeiro, R. C.; Turcq, B.; Sifeddine, A.

    2009-12-01

    Soil samples were collected at 9 different depths, from zero to 100 cm at six points distributed along a transect of 1700 m in upland and lowland areas of the Km 41 reserve near Manaus in Central Brazilian Amazonia, in order to compare the frequency, dimension and extension of past fires in different topographic environmental situations. The average charcoal mass distribution is higher in uplands than in lowlands. This distribution shows a gradient with a high correlation between the two topographic levels, demonstrating a characteristic depth distribution pattern. The highest charcoal concentrations were found at a depth of 20-50 cm in all the six profiles. These fires have affected the upland areas more severely than the lowlands, probably allowing the survival of the vegetation along the small streams.. Two periods of intense fire activity were identified through the distribution of the biomass of charcoal: from around 1320 cal yr BP (ca 1400 14C yr BP) to 1050 cal yr BP (ca 1100 14C yr BP), and between 610 cal yr BP (ca 600 14C yr BP) to 330 cal yr BP (ca 300 yr 14C yr BP). These forest fire phases were probably favored by dry climate which is recorded in other regions of Amazonia and South America by archaeological and palaeoecological data.. Observe that the data found in this article related to the disturbances of fire events in the Central Amazon region appear to be synchronous with events of disruption of populations and vegetation changes and background to the development of indigenous people. Thus it seems plausible that these disturbance phenomena may have an origin presumably climatic than anthropogenic. This possible relationship between climate and forest, ecosystems of high productivity and biomass, and humans should be look carefully in relation to the carbon cycle dynamics demonstrated by the air bubbles extracted of the ice core records.. Increase is observed in the CO2 concentration of the Taylor Dome record just after the increase in frequency

  4. Variability within the 10-year pollen rain of a seasonal neotropical forest and its implications for paleoenvironmental and phenological research.

    PubMed

    Haselhorst, Derek S; Moreno, J Enrique; Punyasena, Surangi W

    2013-01-01

    Tropical paleoecologists use a combination of mud-water interface and modern pollen rain samples (local samples of airborne pollen) to interpret compositional changes within fossil pollen records. Taxonomic similarities between the composition of modern assemblages and fossil samples are the basis of reconstructing paleoclimates and paleoenvironments. Surface sediment samples reflect a time-averaged accumulation of pollen spanning several years or more. Due to experimental constraints, modern pollen rain samples are generally collected over shorter timeframes (1-3 years) and are therefore less likely to capture the full range of natural variability in pollen rain composition and abundance. This potentially biases paleoenvironmental interpretations based on modern pollen rain transfer functions. To determine the degree to which short-term environmental change affects the composition of the aerial pollen flux of Neotropical forests, we sampled ten years of the seasonal pollen rain from Barro Colorado Island, Panama and compared it to climatic and environmental data over the same ten-year span. We establish that the pollen rain effectively captured the strong seasonality and stratification of pollen flow within the forest canopy and that individual taxa had variable sensitivity to seasonal and annual changes in environmental conditions, manifested as changes in pollen productivity. We conclude that modern pollen rain samples capture the reproductive response of moist tropical plants to short-term environmental change, but that consequently, pollen rain-based calibrations need to include longer sampling periods (≥7 years) to reflect the full range of natural variability in the pollen output of a forest and simulate the time-averaging present in sediment samples. Our results also demonstrate that over the long-term, pollen traps placed in the forest understory are representative samples of the pollen output of both canopy and understory vegetation. Aerial pollen traps

  5. Three new cecidogenous species of Palaeomystella Fletcher (Lepidoptera, Momphidae) from the Brazilian Atlantic Rain Forest

    PubMed Central

    Luz, Fernando A.; Gonçalves, Gislene L.; Moreira, Gilson R. P.; Becker, Vitor O.

    2014-01-01

    Abstract Three new cecidogenous species of Palaeomystella Fletcher (Lepidoptera, Momphidae) from the Brazilian Atlantic Rain Forest are described. Larvae of P. fernandesi Moreira & Becker, sp. n., P. rosaemariae Moreira & Becker, sp. n. and P. tavaresi Becker & Moreira, sp. n. induce galls, respectively, on Tibouchina sellowiana (Cham.) Cogn., T. asperior (Cham.) Cogn. and T. fissinervia (Schrank & Mart. ex DC.) Cogn. (Melastomataceae). Adults, immature stages and galls are illustrated, and data on life history and a preliminary analysis of mitochondrial DNA sequences, including related species, are also provided. PMID:25152676

  6. Applications of a hand-held GPS receiver in South American rain forests

    NASA Technical Reports Server (NTRS)

    Baksh, Michael

    1991-01-01

    A hand-held Global Positioning System receiver was used to determine the precise locations of villages, houses, gardens, and other cultural and environmental features in poorly mapped South American rain forests. The Magellan NAV 1000 unit profides extremely accurate latitude and longitude information, but determination of altitude is problematical. Overall, the receiver effectively allows anthropologists to obtain essential locational data useful for categorizing land uses, mapping tribal boundaries, and other applications in regions where environmental conditions are harsh and/or accessibility is difficult.

  7. Isolation of fecal coliforms from pristine sites in a tropical rain forest.

    PubMed

    Rivera, S C; Hazen, T C; Toranzos, G A

    1988-02-01

    Samples collected from water accumulated in leaf axilae of bromeliads (epiphytic flora) in a tropical rain forest were found to harbor fecal coliforms. Random identification of fecal coliform-positive isolates demonstrated the presence of Escherichia coli. This bacterium was also isolated from bromeliad leaf surfaces. These data indicate that E. coli may be part of the phyllosphere microflora and not simply a transient bacterium of this habitat. The isolation of fecal coliforms from these sites was unexpected and raises questions as to the validity of using fecal coliforms as indicators of biological water quality in the tropics. PMID:3281583

  8. Carbon dioxide uptake by an undisturbed tropical rain forest in southwest Amazonia, 1992 to 1993

    SciTech Connect

    Grace, J.; McIntyre, J.; Meir, P.

    1995-11-03

    Measurements of carbon dioxide flux over undisturbed tropical rain forest in Brazil for 55 days in the wet and dry seasons of 1992 to 1993 show that this ecosystem is a net absorber of carbon dioxide. Photosynthetic gains of carbon dioxide exceeded respiratory losses irrespective of the season. These gains cannot be attributed to measurement error, nor to loss of carbon dioxide by drainage of cold air at night. A process-based model, fitted to the data, enabled estimation of the carbon absorbed by the ecosystem over the year as 8.5 {plus_minus} 2.0 moles per square meter per year. 27 refs., 4 figs.

  9. Seed rain dynamics following disturbance exclusion in a secondary tropical dry forest in Morelos, Mexico.

    PubMed

    Ceccon, Eliane; Hernández, Patricia

    2009-01-01

    In most of the legally protected areas in Mexico local inhabitants use natural resources, such as fire wood or cattle grazing. These frequent but low-intensity disturbances have consequences at various levels of the tropical ecosystems and strongly impact forest structure and its regeneration capacity. Despite their importance, the effects of these perturbations in many aspects of tropical forest ecology and in the forest's capacity to recover after disturbance exclusion remain poorly understood. Understanding the impact of these processes on tropical forests is necessary for rehabilitating these forests and enhancing their productivity. In this study, we evaluate the impact of twelve years of exclusion (E) of cattle grazing and fire wood extraction in the composition and dynamics of seed rain, and compare this assessment to a similar analysis in an area where these perturbations continued (without exclusion, WE). We found a strong seasonality in seed rain (96% of seeds fell in the dry season) in both areas. There were no significant differences between E and WE sites in relation to overall seed density, species richness and diversity. However, the distribution along the year of seed species density was significantly different among the E and WE sites. The Jaccard's similarity index between E and WE sites was relatively low (0.57). Barochory was the most common dispersal mode observed among the 23 species in terms of seed species density (48%), followed by anemochory (39%) and zoochory (13%). In relation to seed density, anemochory was the most frequent dispersal mode (88%). Most species in the zone were categorized as small seeds (92%), and there were no significant differences in the distribution of seed size between E and WE. The spatial pattern of dispersal of the four species with the highest relative importance value index, in both areas, was aggregated. Twelve years of disturbance exclusion were not enough to fully restore the seed rain of the area; some

  10. Seed rain dynamics following disturbance exclusion in a secondary tropical dry forest in Morelos, Mexico.

    PubMed

    Ceccon, Eliane; Hernández, Patricia

    2009-01-01

    In most of the legally protected areas in Mexico local inhabitants use natural resources, such as fire wood or cattle grazing. These frequent but low-intensity disturbances have consequences at various levels of the tropical ecosystems and strongly impact forest structure and its regeneration capacity. Despite their importance, the effects of these perturbations in many aspects of tropical forest ecology and in the forest's capacity to recover after disturbance exclusion remain poorly understood. Understanding the impact of these processes on tropical forests is necessary for rehabilitating these forests and enhancing their productivity. In this study, we evaluate the impact of twelve years of exclusion (E) of cattle grazing and fire wood extraction in the composition and dynamics of seed rain, and compare this assessment to a similar analysis in an area where these perturbations continued (without exclusion, WE). We found a strong seasonality in seed rain (96% of seeds fell in the dry season) in both areas. There were no significant differences between E and WE sites in relation to overall seed density, species richness and diversity. However, the distribution along the year of seed species density was significantly different among the E and WE sites. The Jaccard's similarity index between E and WE sites was relatively low (0.57). Barochory was the most common dispersal mode observed among the 23 species in terms of seed species density (48%), followed by anemochory (39%) and zoochory (13%). In relation to seed density, anemochory was the most frequent dispersal mode (88%). Most species in the zone were categorized as small seeds (92%), and there were no significant differences in the distribution of seed size between E and WE. The spatial pattern of dispersal of the four species with the highest relative importance value index, in both areas, was aggregated. Twelve years of disturbance exclusion were not enough to fully restore the seed rain of the area; some

  11. Physiological characteristics of tropical rain forest tree species: a basis for the development of silvicultural technology.

    PubMed

    Sasaki, Satohiko

    2008-01-01

    The physiological characteristics of the dominant tree species in the tropical rain forest mainly belonging to dipterocarps as well as the environmental conditions especially for the light in the forest were studied to establish the silvicultural system for the forest regeneration in the tropical South Asia. The flowering patterns of the dipterocarp trees are usually irregular and unpredictable, which make difficult to collect sufficient seeds for raising the seedlings. The field survey revealed the diverged features of the so-called gregarious or simultaneous flowering of various species of this group. Appropriate conditions and methods for the storage of the seeds were established according to the detailed analyses of the morphological and physiological characteristics of the seeds such as the low temperature tolerance and the moisture contents. The intensity and spectra of the light in the forest primarily determine the growth and the morphological development of the seedlings under the canopy. Based on the measurements of the diffused light at the sites in the tropical forest in the varying sunlight, the parameters such as "the steady state of the diffuse light" and "the turning point" were defined, which were useful to evaluate the light conditions in the forest. To improve the survival of the transplanted seedlings, a planting method of "the bare-root seedlings", the seedlings easy to be handled by removal of all leaves, soil and pots, was developed. Its marked efficiency was proved with various dipterocarps and other tropical trees by the field trial in the practical scale. Tolerance of the various species to the extreme environmental conditions such as fires, acid soils and drought were examined by the experiments and the field survey, which revealed marked adaptability of Shorea roxburghii as a potential species for regeneration of the tropical forests.

  12. Physiological characteristics of tropical rain forest tree species: A basis for the development of silvicultural technology

    PubMed Central

    SASAKI, Satohiko

    2008-01-01

    The physiological characteristics of the dominant tree species in the tropical rain forest mainly belonging to dipterocarps as well as the environmental conditions especially for the light in the forest were studied to establish the silvicultural system for the forest regeneration in the tropical South Asia. The flowering patterns of the dipterocarp trees are usually irregular and unpredictable, which make difficult to collect sufficient seeds for raising the seedlings. The field survey revealed the diverged features of the so-called gregarious or simultaneous flowering of various species of this group. Appropriate conditions and methods for the storage of the seeds were established according to the detailed analyses of the morphological and physiological characteristics of the seeds such as the low temperature tolerance and the moisture contents. The intensity and spectra of the light in the forest primarily determine the growth and the morphological development of the seedlings under the canopy. Based on the measurements of the diffused light at the sites in the tropical forest in the varying sunlight, the parameters such as “the steady state of the diffuse light” and “the turning point” were defined, which were useful to evaluate the light conditions in the forest. To improve the survival of the transplanted seedlings, a planting method of “the bare-root seedlings”, the seedlings easy to be handled by removal of all leaves, soil and pots, was developed. Its marked efficiency was proved with various dipterocarps and other tropical trees by the field trial in the practical scale. Tolerance of the various species to the extreme environmental conditions such as fires, acid soils and drought were examined by the experiments and the field survey, which revealed marked adaptability of Shorea roxburghii as a potential species for regeneration of the tropical forests. PMID:18941286

  13. Cruising the rain forest floor: butterfly wing shape evolution and gliding in ground effect.

    PubMed

    Cespedes, Ann; Penz, Carla M; DeVries, Philip J

    2015-05-01

    Flight is a key innovation in the evolutionary success of insects and essential to dispersal, territoriality, courtship and oviposition. Wing shape influences flight performance and selection likely acts to maximize performance for conducting essential behaviours that in turn results in the evolution of wing shape. As wing shape also contributes to fitness, optimal shapes for particular flight behaviours can be assessed with aerodynamic predictions and placed in an ecomorphological context. Butterflies in the tribe Haeterini (Nymphalidae) are conspicuous members of understorey faunas in lowland Neotropical forests. Field observations indicate that the five genera in this clade differ in flight height and behaviour: four use gliding flight at the forest floor level, and one utilizes flapping flight above the forest floor. Nonetheless, the association of ground level gliding flight behaviour and wing shape has never been investigated in this or any other butterfly group. We used landmark-based geometric morphometrics to test whether wing shapes in Haeterini and their close relatives reflected observed flight behaviours. Four genera of Haeterini and some distantly related Satyrinae showed significant correspondence between wing shape and theoretical expectations in performance trade-offs that we attribute to selection for gliding in ground effect. Forewing shape differed between sexes for all taxa, and male wing shapes were aerodynamically more efficient for gliding flight than corresponding females. This suggests selection acts differentially on male and female wing shapes, reinforcing the idea that sex-specific flight behaviours contribute to the evolution of sexual dimorphism. Our study indicates that wing shapes in Haeterini butterflies evolved in response to habitat-specific flight behaviours, namely gliding in ground effect along the forest floor, resulting in ecomorphological partitions of taxa in morphospace. The convergent flight behaviour and wing morphology

  14. Threshold Responses to Soil Moisture Deficit by Trees and Soil in Tropical Rain Forests: Insights from Field Experiments

    PubMed Central

    Meir, Patrick; Wood, Tana E.; Galbraith, David R.; Brando, Paulo M.; Da Costa, Antonio C. L.; Rowland, Lucy; Ferreira, Leandro V.

    2015-01-01

    Many tropical rain forest regions are at risk of increased future drought. The net effects of drought on forest ecosystem functioning will be substantial if important ecological thresholds are passed. However, understanding and predicting these effects is challenging using observational studies alone. Field-based rainfall exclusion (canopy throughfall exclusion; TFE) experiments can offer mechanistic insight into the response to extended or severe drought and can be used to help improve model-based simulations, which are currently inadequate. Only eight TFE experiments have been reported for tropical rain forests. We examine them, synthesizing key results and focusing on two processes that have shown threshold behavior in response to drought: (1) tree mortality and (2) the efflux of carbon dioxdie from soil, soil respiration. We show that: (a) where tested using large-scale field experiments, tropical rain forest tree mortality is resistant to long-term soil moisture deficit up to a threshold of 50% of the water that is extractable by vegetation from the soil, but high mortality occurs beyond this value, with evidence from one site of increased autotrophic respiration, and (b) soil respiration reaches its peak value in response to soil moisture at significantly higher soil moisture content for clay-rich soils than for clay-poor soils. This first synthesis of tropical TFE experiments offers the hypothesis that low soil moisture–related thresholds for key stress responses in soil and vegetation may prove to be widely applicable across tropical rain forests despite the diversity of these forests. PMID:26955085

  15. Off-nadir antenna bias correction using Amazon rain forest sigma deg data. [Brazil

    NASA Technical Reports Server (NTRS)

    Birrer, I. J.; Bracalente, E. M.; Dome, G. J.; Sweet, J.; Berthold, G.; Moore, R. K. (Principal Investigator)

    1981-01-01

    The radar response from the Amazon rain forest was studied to determine the suitability of this region for use as a standard target to calibrate a scatterometer like that proposed for the National Ocean Satellite System (NOSS). Backscattering observations made by the SEASAT-1 scatterometer system show the Amazon rain forest to be a homogeneous, azimuthally-isotropic, radar target which is insensitive to polarization. The variation with angle of incidence may be adequately modeled as sigma deg (dB) = alpha theta + beta with typical values for the incidence-angle coefficient from 0.07 dB deg to 0.15 dB/deg. A small diurnal effect occurs, with measurements at sunrise being 0.5 dB to 1 dB higher than the rest of the day. Maximum likelihood estimation algorithms are presented which permit determination of relative bias and true pointing angle for each beam. Specific implementation of these algorithms for the proposed NOSS scatterometer system is also discussed.

  16. Comparative study of understorey birds diversity inhabiting lowland rainforest virgin jungle reserve and regenerated forest.

    PubMed

    Nor Hashim, Ezyan; Ramli, Rosli

    2013-01-01

    A comparative study of understorey birds inhabiting different habitats, that is, virgin jungle reserve (VJR) and regenerated forest (RF), was conducted in Ulu Gombak Forest Reserve and Selangor and Triang Forest Reserve, Negeri Sembilan, Peninsular Malaysia. The objective of this study was to assess the diversity of understorey birds in both habitats and the effects of forest regeneration on the understorey bird community. The mist-netting method was used to capture understorey birds inhabiting both habitats in both locations. Species composition and feeding guild indicated that understorey bird populations were similar in the two habitats. However, the number of secondary forest species such as Little spiderhunter (Arachnothera longirostra) in VJR is increasing due to its proximity to RF. This study discovered that RFs in both study areas are not yet fully recovered. However, based on the range of species discovered, the RFs have conservation value and should be maintained because they harbour important forest species such as babblers and flycatchers. The assessment of the community structure of understorey birds in VJR and RF is important for forest management and conservation, especially where both habitats are intact.

  17. Effects of fire on the thermal stability of permafrost in lowland and upland black spruce forests of interior Alaska in a changing climate

    USGS Publications Warehouse

    Jafarov, Elchin E.; Romanovsky, Vladimir E.; Genet, Helene; McGuire, Anthony David; Marchenko, Sergey S.

    2013-01-01

    Fire is an important factor controlling the composition and thickness of the organic layer in the black spruce forest ecosystems of interior Alaska. Fire that burns the organic layer can trigger dramatic changes in the underlying permafrost, leading to accelerated ground thawing within a relatively short time. In this study, we addressed the following questions. (1) Which factors determine post-fire ground temperature dynamics in lowland and upland black spruce forests? (2) What levels of burn severity will cause irreversible permafrost degradation in these ecosystems? We evaluated these questions in a transient modeling–sensitivity analysis framework to assess the sensitivity of permafrost to climate, burn severity, soil organic layer thickness, and soil moisture content in lowland (with thick organic layers, ~80 cm) and upland (with thin organic layers, ~30 cm) black spruce ecosystems. The results indicate that climate warming accompanied by fire disturbance could significantly accelerate permafrost degradation. In upland black spruce forest, permafrost could completely degrade in an 18 m soil column within 120 years of a severe fire in an unchanging climate. In contrast, in a lowland black spruce forest, permafrost is more resilient to disturbance and can persist under a combination of moderate burn severity and climate warming.

  18. Nitrogen and phosphorus resorption in a neotropical rain forest of a nutrient-rich soil.

    PubMed

    Martínez-Sánchez, José Luis

    2005-01-01

    In tropical forests with nutrient-rich soil tree's nutrient resorption from senesced leaves has not always been observed to be low. Perhaps this lack of consistence is partly owing to the nutrient resorption methods used. The aim of the study was to analyse N and P resorption proficiency from tropical rain forest trees in a nutrient-rich soil. It was hypothesised that trees would exhibit low nutrient resorption in a nutrient-rich soil. The soil concentrations of total N and extractable P, among other physical and chemical characteristics, were analysed in 30 samples in the soil surface (10 cm) of three undisturbed forest plots at 'Estaci6n de Biologia Los Tuxtlas' on the east coast of Mexico (18 degrees 34' - 18 degrees 36' N, 95 degrees 04' - 95 degrees 09' W). N and P resorption proficiency were determined from senescing leaves in 11 dominant tree species. Nitrogen was analysed by microkjeldahl digestion with sulphuric acid and distilled with boric acid, and phosphorus was analysed by digestion with nitric acid and perchloric acid. Soil was rich in total N (0.50%, n = 30) and extractable P (4.11 microg g(-1) n = 30). As expected, trees showed incomplete N (1.13%, n = 11) and P (0.11%, n = 1) resorption. With a more accurate method of nutrient resorption assessment, it is possible to prove that a forest community with a nutrient-rich soil can have low levels of N and P resorption.

  19. Seasonal trends of dry and bulk concentration of nitrogen compounds over a rain forest in Ghana

    NASA Astrophysics Data System (ADS)

    Fattore, F.; Bertolini, T.; Materia, S.; Gualdi, S.; Thongo M'Bou, A.; Nicolini, G.; Valentini, R.; De Grandcourt, A.; Tedesco, D.; Castaldi, S.

    2014-06-01

    African tropical forests of the equatorial belt might receive significant input of extra nitrogen derived from biomass burning occurring in the north savanna belt and transported equatorward by northeastern winds. In order to test this hypothesis an experiment was set up in a tropical rain forest in the Ankasa Game Reserve and Nini-Suhien National Park (Ghana) aimed at quantifying magnitude and seasonal variability of concentrations of N compounds, present as gas and aerosol (dry nitrogen) or in the rainfall (bulk nitrogen), over the studied forest; and relating their seasonal variability to trends of local and regional winds and rainfall and to variations of fire events in the region. Three DELTA systems, implemented for monthly measurements of NO2, were mounted over a tower at 45 m height, 20 m above forest canopy to sample gas (NH3, NO2, HNO3, HCl, SO2) and aerosol (NH4+, NO3-, and several ions), together with three tanks for bulk rainfall collection (to analyze NH4+, NO3- and ion concentration). The tower was provided with a sonic anemometer to estimate local wind data. The experiment started in October 2011 and data up to October 2012 are presented. To interpret the observed seasonal trends of measured compounds, local and regional meteo data and regional satellite fire data were analyzed. The concentration of N compounds significantly increased from December to April, during the drier period, peaking from December to February when NE winds (the Harmattan) were moving dry air masses over the west-central African region, and the Intertropical Convergence Zone (ITCZ) was at its minimum latitude over the Equator. This period also coincided with fire peaks in the whole region. On the contrary, N concentration in gas, aerosol and rain decreased from May to October when prevalent winds arrived from the sea (southeast), during the monsoon period. Both ionic compositions of rain and analysis of local wind direction showed a significant and continuous presence of see

  20. Biomass Burning:Significant Source of Nitrate and Sulfate for the Andean Rain Forest in Ecuador

    NASA Astrophysics Data System (ADS)

    Fabian, P.; Rollenbeck, R.; Spichtinger, N.

    2009-04-01

    Forest fires are significant sources of carbon, sulfur and nitrogen compounds which, along with their photochemically generated reaction products, can be transported over very long distances, even traversing oceans. Chemical analyses of rain and fogwater samples collected on the wet eastern slopes of the Ecuadorian Andes show frequent episodes of high sulfate and nitrate concentration, from which annual deposition rates of about14 kg/ha and 7 kg/ha ,respectively, are derived. These are comparable to those observed in polluted central Europe. Regular rain and fogwater sampling along an altitude profile between 1800 and 3185 m, has been carried out since 2002.The research area located at 30 58'S ,790 5' W is dominated by trade winds from easterly directions. The samples, generally accumulated over 1-week intervals, were analysed for pH, conductivity and major ions(K+,Na+,NH4+,Ca2+,Mg 2+,SO42-,NO3-,PO43-).For all components a strong seasonal variation is observed, while the altitudinal gradient is less pronounced. About 65 % of the weekly samples were significantly loaded with cations and anions, with pH often as low 3.5 to 4.0 and conductivity up to 50 uS/cm. Back trajectories (FLEXTRA) showed that respective air masses had passed over areas of intense biomass burning, sometimes influenced by volcanoes, ocean spray, or even episodic Sahara and/or Namib desert dust interference not discussed here. Enhanced SO4 2-and NO3- were identified, by combining satellite-based fire pixels with back trajectories, as predominantly resulting from biomass burning. For most cases, by using emission inventories, anthropogenic precursor sources other than forest fires play a minor role, thus leaving biomass burning as the main source of nitrate and sulphate in rain and fogwater. Some SO4 2- , about 10 % of the total input, could be identified to originate from active volcanoes, whose plumes were sometimes encountered by the respective back trajectories. While volcanic, oceanic and

  1. Variation in forest structure and carbon dynamics in tropical rain forests of Amazonia

    NASA Astrophysics Data System (ADS)

    Vieira, S.; Selhorst, D.; Hutyra, L.; da Silva, R.; Camargo, P.; Chambers, J. Q.; Brown, I. F.; Higuchi, N.; Dos Santos, J.; Martinelli, L. A.; Trumbore, S.

    2002-12-01

    A better understanding of the variations in the dynamics and structure of trees in tropical forests is necessary for predicting the potential for these ecosystems to lose or store carbon. Data from forest inventory plotsshow large differences in forest structure, biomass, and tree growth rates among plots in three location. The number of stems (g.t. 10cm diameter)per hectare is higher in the Manaus site (626 ha-1) than in the Rio Branco (466 ha-1) or Santrem (460 ha-1) sites. Stocks of C in above-ground biomass in the three areas were 180.1 (Manaus), 122.1 (Rio Branco), and 140.6 (Santarem) MgC ha-1. Estimates of mean annual accumulation of C in living trees based on monthly dendrometer band measurements ranged from 1.6 (Manaus), 2.5 (Rio Branco), to 2.8 (Santarem) MgC ha-1 yr-1. Our results showed marked seasonality to growth, with highest growth rates in the wet and lowest rates in the dry season. This effect was most pronounced for trees with diameter g. t. 50cm. Comparing the three areas investigated suggests that forests experiencing a longer dry season have larger annual diameter growth increments for individual trees, and more of the forest biomass in the largest trees.

  2. Variations of ice nuclei concentration induced by rain and snowfall within a local forested site in Japan

    NASA Astrophysics Data System (ADS)

    Hara, Kazutaka; Maki, Teruya; Kobayashi, Fumihisa; Kakikawa, Makiko; Wada, Masashi; Matsuki, Atsushi

    2016-02-01

    Biological ice nuclei (IN) such as certain species of bacteria and fungi are believed to have impacts on ice nucleation in mixed-phase clouds at temperatures warmer than -15 °C. Recent studies have indicated that rain is closely related to increases of biological IN in the near-surface atmosphere. However, variations of IN concentrations during rain and snowfall have not been compared. In the present study, field measurements of atmospheric IN were carried out under fine, cloudy, rain and snow at a local forested site in Japan. IN concentrations at -7 °C in spring were dramatically increased by rain, and concentrations associated with rain (0.86-2.2 m-3) were greater than 2.6 times higher than the mean concentration during fine weather (0.33 m-3). In winter, concentrations associated with rain (1.6 to >5.7 m-3) were also higher than those under cloudy sky (1.1 m-3), but increases were not observed during snowfall (0.21-0.4 m-3). Detectable IN concentrations associated with rain considerably decreased after heat treatment at 90 °C, indicating that IN increased during rain were likely biological substances such as heat-sensitive ice nucleation active proteins. Consequently, different types of precipitation may have varying effects on IN concentration associated with biological substances.

  3. Characterizing the Phylogenetic Tree Community Structure of a Protected Tropical Rain Forest Area in Cameroon

    PubMed Central

    Munoz, François; Couteron, Pierre; Hardy, Olivier J.; Sonké, Bonaventure

    2014-01-01

    Tropical rain forests, the richest terrestrial ecosystems in biodiversity on Earth are highly threatened by global changes. This paper aims to infer the mechanisms governing species tree assemblages by characterizing the phylogenetic structure of a tropical rain forest in a protected area of the Congo Basin, the Dja Faunal Reserve (Cameroon). We re-analyzed a dataset of 11538 individuals belonging to 372 taxa found along nine transects spanning five habitat types. We generated a dated phylogenetic tree including all sampled taxa to partition the phylogenetic diversity of the nine transects into alpha and beta components at the level of the transects and of the habitat types. The variation in phylogenetic composition among transects did not deviate from a random pattern at the scale of the Dja Faunal Reserve, probably due to a common history and weak environmental variation across the park. This lack of phylogenetic structure combined with an isolation-by-distance pattern of taxonomic diversity suggests that neutral dispersal limitation is a major driver of community assembly in the Dja. To assess any lack of sensitivity to the variation in habitat types, we restricted the analyses of transects to the terra firme primary forest and found results consistent with those of the whole dataset at the level of the transects. Additionally to previous analyses, we detected a weak but significant phylogenetic turnover among habitat types, suggesting that species sort in varying environments, even though it is not predominating on the overall phylogenetic structure. Finer analyses of clades indicated a signal of clustering for species from the Annonaceae family, while species from the Apocynaceae family indicated overdispersion. These results can contribute to the conservation of the park by improving our understanding of the processes dictating community assembly in these hyperdiverse but threatened regions of the world. PMID:24936786

  4. Characterizing the phylogenetic tree community structure of a protected tropical rain forest area in Cameroon.

    PubMed

    Manel, Stéphanie; Couvreur, Thomas L P; Munoz, François; Couteron, Pierre; Hardy, Olivier J; Sonké, Bonaventure

    2014-01-01

    Tropical rain forests, the richest terrestrial ecosystems in biodiversity on Earth are highly threatened by global changes. This paper aims to infer the mechanisms governing species tree assemblages by characterizing the phylogenetic structure of a tropical rain forest in a protected area of the Congo Basin, the Dja Faunal Reserve (Cameroon). We re-analyzed a dataset of 11538 individuals belonging to 372 taxa found along nine transects spanning five habitat types. We generated a dated phylogenetic tree including all sampled taxa to partition the phylogenetic diversity of the nine transects into alpha and beta components at the level of the transects and of the habitat types. The variation in phylogenetic composition among transects did not deviate from a random pattern at the scale of the Dja Faunal Reserve, probably due to a common history and weak environmental variation across the park. This lack of phylogenetic structure combined with an isolation-by-distance pattern of taxonomic diversity suggests that neutral dispersal limitation is a major driver of community assembly in the Dja. To assess any lack of sensitivity to the variation in habitat types, we restricted the analyses of transects to the terra firme primary forest and found results consistent with those of the whole dataset at the level of the transects. Additionally to previous analyses, we detected a weak but significant phylogenetic turnover among habitat types, suggesting that species sort in varying environments, even though it is not predominating on the overall phylogenetic structure. Finer analyses of clades indicated a signal of clustering for species from the Annonaceae family, while species from the Apocynaceae family indicated overdispersion. These results can contribute to the conservation of the park by improving our understanding of the processes dictating community assembly in these hyperdiverse but threatened regions of the world.

  5. Contrasting structure and composition of the understory in species-rich tropical rain forests.

    PubMed

    LaFrankie, James V; Ashton, Peter S; Chuyong, George B; Co, Leonardo; Condit, Richard; Davies, Stuart J; Foster, Robin; Hubbell, Stephen P; Kenfack, David; Lagunzad, Daniel; Losos, Elizabeth C; Nor, Noor Supardi Md; Tan, Sylvester; Thomas, Duncan W; Valencia, Renato; Villa, Gorky

    2006-09-01

    In large samples of trees > or = 1 cm dbh (more than 1 million trees and 3000 species), in six lowland tropical forests on three continents, we assigned species with >30 individuals to one of six classes of stature at maturity (SAM). We then compared the proportional representation of understory trees (1-2 cm dbh) among these classes. The understory of the three Asian sites was predominantly composed of the saplings of large-canopy trees whereas the African and American sites were more richly stocked with trees of the smaller SAM classes. Differences in class representation were related to taxonomic families that were present exclusively in one continent or another. Families found in the Asian plots but not in the American plot (e.g., Dipterocarpaceae, Fagaceae) were predominantly species of the largest SAM classes, whereas families exclusive to the American plots (e.g., Melastomataceae sensu stricto, Piperaceae, and Malvaceae [Bombacacoidea]) were predominantly species of small classes. The African plot was similar to Asia in the absence of those American families rich in understory species, while similar to America in lacking the Asian families rich in canopy species. The numerous understory species of Africa were chiefly derived from families shared with Asia and/or America. The ratio of saplings (1-2 cm dbh) to conspecific canopy trees (>40 cm dbh) was lower in American plots than in the Asian plots. Possible explanations for these differences include phenology, moisture and soil fertility regimes, phyletic constraints, and the role of early successional plants in forest development. These results demonstrate that tropical forests that appear similar in tree number, basal area, and the family taxonomy of canopy trees nonetheless differ in ecological structure in ways that may impact the ecology of pollinators, dispersers, and herbivores and might reflect fundamental differences in canopy tree regeneration. PMID:16995630

  6. On the potential of long wavelength imaging radars for mapping vegetation types and woody biomass in tropical rain forests

    NASA Technical Reports Server (NTRS)

    Rignot, Eric J.; Zimmermann, Reiner; Oren, Ram

    1995-01-01

    In the tropical rain forests of Manu, in Peru, where forest biomass ranges from 4 kg/sq m in young forest succession up to 100 kg/sq m in old, undisturbed floodplain stands, the P-band polarimetric radar data gathered in June of 1993 by the AIRSAR (Airborne Synthetic Aperture Radar) instrument separate most major vegetation formations and also perform better than expected in estimating woody biomass. The worldwide need for large scale, updated biomass estimates, achieved with a uniformly applied method, as well as reliable maps of land cover, justifies a more in-depth exploration of long wavelength imaging radar applications for tropical forests inventories.

  7. The Effect of the Landscape Matrix on the Distribution of Dung and Carrion Beetles in a Fragmented Tropical Rain Forest

    PubMed Central

    Díaz, Alfonso; Galante, Eduardo; Favila, Mario E.

    2010-01-01

    Understanding the response of species to anthropogenic landscape modification is essential to design effective conservation programs. Recently, insects have been used in empirical studies to evaluate the impact of habitat modification and landscape fragmentation on biological diversity because they are often affected rapidly by changes in land use. In this study, the use of the landscape matrix by dung and carrion beetles in a fragmented tropical rain forest in the Los Tuxtlas Biosphere Reserve was analyzed. Fragments of tropical rain forest, forest-pasture edges, pastures, isolated trees, living fences (trees connected with barbed wire) and barbed wire fences were studied both near and far from forest fragments. Forest fragments had the highest abundance values, but pastures had the highest dung and carrion beetle biomass. Habitat specificity was high for the beetles in the most dissimilar habitats. Forest fragments and forest-pasture edges had and shared the highest number of species, but they shared only two species with pastures, barbed wire fences and isolated trees. Only one forest species was found within living fences far from the forest fragments. However, approximately 37% of the forest species were caught within living fences near the forest fragments. Therefore, forest-pasture edges function as hard edges and prevent movement among forest fragments, but living fences seem to act as continuous habitat corridors when connected to forest fragments, allowing forest beetles to move between the fragments. Further studies are necessary to determine the minimum width of living fences necessary to provide good corridors for these beetles and other species. PMID:20673066

  8. Mosquito (Diptera: Culicidae) diversity of a forest-fragment mosaic in the Amazon rain forest.

    PubMed

    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.

  9. Effects of termite activities on coarse woody debris decomposition in an intact lowland mixed dipterocarp forest of Brunei Darussalam

    NASA Astrophysics Data System (ADS)

    Lee, Sohye; Kim, Seungjun; Roh, Yujin; Abu Salim, Kamariah; Lee, Woo-Kyun; Davies, Stuart; Son, Yowhan

    2016-04-01

    Tropical forests have been considered important ecosystems in terms of carbon cycle and climate change, because they sequester carbon more than any other terrestrial ecosystems. In addition, coarse woody debris is one of the main carbon storages, accounting for 10 - 40% of the tropical forest carbon. Carbon in coarse woody debris is released by various activities of organisms, and particularly termite's feeding activities are known to be main process in tropical forests. Therefore, investigating the effects of termite activities on coarse woody debris decomposition is important to understanding carbon cycles of tropical forests. This study was conducted in an intact lowland mixed dipterocarp forest (MDF) of Brunei Darussalam, and three main MDF tree species (Dillenia beccariana, Macaranga bancana, and Elateriospermum tapos) were selected. Coarse woody debris samples of both 10 cm diameter and length were prepared, and half of samples were covered twice with nylon net (mesh size 1.5 mm × 1.5 mm) to prevent termite's approach. Three 2 m × 11 m permanent plots were installed in January, 2015 and eighteen samples per plot (3 species × 2 treatments × 3 repetitions) were placed at the soil surface. Weights of each sample were recorded at initial time, and weighed again in August, 2015. On average, uncovered and covered samples lost 18.9 % and 3.3 % of their initial weights, respectively. Weight loss percentage was highest in uncovered samples of M. bancana (23.9 %), and lowest in covered samples of E. tapos (7.8 %). Two-way ANOVA showed that tree species and termite exclusion treatment had statistically significant effects on coarse woody debris decomposition (P = 0.0001). The effect of species and termite exclusion treatment interaction was also statistically significant (P = 0.0001). The result reveals that termite activities promote the coarse woody debris decomposition and they influence differently along the wood species. However, many samples of D. beccariana

  10. Effects of termite activities on coarse woody debris decomposition in an intact lowland mixed dipterocarp forest of Brunei Darussalam

    NASA Astrophysics Data System (ADS)

    Lee, Sohye; Kim, Seungjun; Roh, Yujin; Abu Salim, Kamariah; Lee, Woo-Kyun; Davies, Stuart; Son, Yowhan

    2016-04-01

    Tropical forests have been considered important ecosystems in terms of carbon cycle and climate change, because they sequester carbon more than any other terrestrial ecosystems. In addition, coarse woody debris is one of the main carbon storages, accounting for 10 ‑ 40% of the tropical forest carbon. Carbon in coarse woody debris is released by various activities of organisms, and particularly termite's feeding activities are known to be main process in tropical forests. Therefore, investigating the effects of termite activities on coarse woody debris decomposition is important to understanding carbon cycles of tropical forests. This study was conducted in an intact lowland mixed dipterocarp forest (MDF) of Brunei Darussalam, and three main MDF tree species (Dillenia beccariana, Macaranga bancana, and Elateriospermum tapos) were selected. Coarse woody debris samples of both 10 cm diameter and length were prepared, and half of samples were covered twice with nylon net (mesh size 1.5 mm × 1.5 mm) to prevent termite's approach. Three 2 m × 11 m permanent plots were installed in January, 2015 and eighteen samples per plot (3 species × 2 treatments × 3 repetitions) were placed at the soil surface. Weights of each sample were recorded at initial time, and weighed again in August, 2015. On average, uncovered and covered samples lost 18.9 % and 3.3 % of their initial weights, respectively. Weight loss percentage was highest in uncovered samples of M. bancana (23.9 %), and lowest in covered samples of E. tapos (7.8 %). Two-way ANOVA showed that tree species and termite exclusion treatment had statistically significant effects on coarse woody debris decomposition (P = 0.0001). The effect of species and termite exclusion treatment interaction was also statistically significant (P = 0.0001). The result reveals that termite activities promote the coarse woody debris decomposition and they influence differently along the wood species. However, many samples of D. beccariana

  11. Strategies for reducing carbon emissions on the tropical rain forest: The case of the Brazilian Amazon

    SciTech Connect

    Freitas, M.A.V. de; Rosa, L.P.

    1995-11-01

    Forests systems are renewable resources that can be used by present generations and that should be available to future generations if they are exploited on a sustainable basis. The tropical forest is still an immense and unknown field. The issues are: What means a sustainable basis in the tropical rain forests? What are the means of harmonising an economic development with an environmental equilibrium in tropical regions? One way to meet this requirement is to analyse the potentially {open_quotes}no regrets{close_quotes} options on which it is possible to agree upon despite controversies about what will be the true long run costs and benefits of various courses of actions. In the case of the Brazilian Amazon, in the last thirty years, the use of biomass and land has increased rapidly. Therefore, environmental and social problems have emerged with some intensity and have had repercussions on local and global scales. In relation to the recent global environmental changes, the Brazilian Amazon is considered as a key region for biodiversity conservation and preserving a carbon sink. In this paper, the main methodological option is to conceive a set of {open_quotes}no-regret{close_quotes} options, related with the land uses and biomass valorisation, which are analysed through the same framework. The options considered here are: decrease of the great cattle ranching and of the predatory timber extraction; the increase of forest management (harvest of timber and nontimber extractive products) and forest plantations in the degraded lands. The aims to focus on three elements: job creation, technico-economic adequation and environmental impacts, with special regards concerning the limitation of the atmospheric emissions of greenhouse gases (carbon flow).

  12. Temperate pine barrens and tropical rain forests are both rich in undescribed fungi.

    PubMed

    Luo, Jing; Walsh, Emily; Naik, Abhishek; Zhuang, Wenying; Zhang, Keqin; Cai, Lei; Zhang, Ning

    2014-01-01

    Most of fungal biodiversity on Earth remains unknown especially in the unexplored habitats. In this study, we compared fungi associated with grass (Poaceae) roots from two ecosystems: the temperate pine barrens in New Jersey, USA and tropical rain forests in Yunnan, China, using the same sampling, isolation and species identification methods. A total of 426 fungal isolates were obtained from 1600 root segments from 80 grass samples. Based on the internal transcribed spacer (ITS) sequences and morphological characteristics, a total of 85 fungal species (OTUs) belonging in 45 genera, 23 families, 16 orders, and 6 classes were identified, among which the pine barrens had 38 and Yunnan had 56 species, with only 9 species in common. The finding that grass roots in the tropical forests harbor higher fungal species diversity supports that tropical forests are fungal biodiversity hotspots. Sordariomycetes was dominant in both places but more Leotiomycetes were found in the pine barrens than Yunnan, which may play a role in the acidic and oligotrophic pine barrens ecosystem. Equal number of undescribed fungal species were discovered from the two sampled ecosystems, although the tropical Yunnan had more known fungal species. Pine barrens is a unique, unexplored ecosystem. Our finding suggests that sampling plants in such unexplored habitats will uncover novel fungi and that grass roots in pine barrens are one of the major reservoirs of novel fungi with about 47% being undescribed species. PMID:25072783

  13. Temperate Pine Barrens and Tropical Rain Forests Are Both Rich in Undescribed Fungi

    PubMed Central

    Luo, Jing; Walsh, Emily; Naik, Abhishek; Zhuang, Wenying; Zhang, Keqin; Cai, Lei; Zhang, Ning

    2014-01-01

    Most of fungal biodiversity on Earth remains unknown especially in the unexplored habitats. In this study, we compared fungi associated with grass (Poaceae) roots from two ecosystems: the temperate pine barrens in New Jersey, USA and tropical rain forests in Yunnan, China, using the same sampling, isolation and species identification methods. A total of 426 fungal isolates were obtained from 1600 root segments from 80 grass samples. Based on the internal transcribed spacer (ITS) sequences and morphological characteristics, a total of 85 fungal species (OTUs) belonging in 45 genera, 23 families, 16 orders, and 6 classes were identified, among which the pine barrens had 38 and Yunnan had 56 species, with only 9 species in common. The finding that grass roots in the tropical forests harbor higher fungal species diversity supports that tropical forests are fungal biodiversity hotspots. Sordariomycetes was dominant in both places but more Leotiomycetes were found in the pine barrens than Yunnan, which may play a role in the acidic and oligotrophic pine barrens ecosystem. Equal number of undescribed fungal species were discovered from the two sampled ecosystems, although the tropical Yunnan had more known fungal species. Pine barrens is a unique, unexplored ecosystem. Our finding suggests that sampling plants in such unexplored habitats will uncover novel fungi and that grass roots in pine barrens are one of the major reservoirs of novel fungi with about 47% being undescribed species. PMID:25072783

  14. Temperate pine barrens and tropical rain forests are both rich in undescribed fungi.

    PubMed

    Luo, Jing; Walsh, Emily; Naik, Abhishek; Zhuang, Wenying; Zhang, Keqin; Cai, Lei; Zhang, Ning

    2014-01-01

    Most of fungal biodiversity on Earth remains unknown especially in the unexplored habitats. In this study, we compared fungi associated with grass (Poaceae) roots from two ecosystems: the temperate pine barrens in New Jersey, USA and tropical rain forests in Yunnan, China, using the same sampling, isolation and species identification methods. A total of 426 fungal isolates were obtained from 1600 root segments from 80 grass samples. Based on the internal transcribed spacer (ITS) sequences and morphological characteristics, a total of 85 fungal species (OTUs) belonging in 45 genera, 23 families, 16 orders, and 6 classes were identified, among which the pine barrens had 38 and Yunnan had 56 species, with only 9 species in common. The finding that grass roots in the tropical forests harbor higher fungal species diversity supports that tropical forests are fungal biodiversity hotspots. Sordariomycetes was dominant in both places but more Leotiomycetes were found in the pine barrens than Yunnan, which may play a role in the acidic and oligotrophic pine barrens ecosystem. Equal number of undescribed fungal species were discovered from the two sampled ecosystems, although the tropical Yunnan had more known fungal species. Pine barrens is a unique, unexplored ecosystem. Our finding suggests that sampling plants in such unexplored habitats will uncover novel fungi and that grass roots in pine barrens are one of the major reservoirs of novel fungi with about 47% being undescribed species.

  15. Diversity and composition of understory vegetation in the tropical seasonal rain forest of Xishuangbanna, SW China.

    PubMed

    Lü, Xiao-Tao; Yin, Jiang-Xia; Tang, Jian-Wei

    2011-03-01

    Tropical forests vegetation and community research have tended to focus on the tree component, and limited attention has been paid to understory vegetation. Species diversity and composition of the understory of tropical seasonal rain forest were inventoried in a 625 m2 area (for sapling layer) and a 100 m2 area (for herb/seedling layer) in three 1 ha plots. We found 3068 individuals belonging to 309 species, 192 genera and 89 families. The most important family as determined by the Family Importance Value (FIV) was Rubiaceae in both sapling and herb/seedling layers. In terms of Importance Value Index (IVI), the shrub Mycetia gracilis (Rubiaceae) was the most important species in the sapling layer and the pteridophyte Selaginella delicatula (Selaginellaceae) was the most ecological significant species in the herb/seedling layer. Much more vascular plant species were registered in the understory than in the tree layer totaled among the three plots. The species diversity did not differ significantly among the tree layer, sapling layer and herb/seedling layer. Given that we still know little about the understory plant community for growth forms other than trees, the results from the present study indicate that more attention should be paid to the understory vegetation during the decision-making process for biodiversity conservation in the tropical forests. PMID:21513205

  16. Primate community of the tropical rain forests of Saracá-Taqüera National Forest, Pará, Brazil.

    PubMed

    Oliveira, L C; Loretto, D; Viana, L R; Silva-Jr, J S; Fernandes, W G

    2009-11-01

    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

  17. Development of a succession model for subtropical rain forest and its application to assess the effects of timber harvest at Wiangaree State Forest, New South Wales

    SciTech Connect

    Shugart, H.H. Jr.; Hopkins, M.S.; Burgess, I.P.; Mortlock, A.T.

    1980-11-01

    The KIAMBRAM model, a computer model of complex notophyll vine forest (subtropical rain forest) in Australia near the New South Wales/Queensland border, is documented and results of the model are presented. The model simulates a 1/20-ha forest stand by considering explicitly the birth, death, and growth of each tree in the stand. The model also allows the selective harvest of any of the 125 species considered at any desired frequency. The model is tested on its ability to simulate species dynamics following disturbance and to predict the composition of mature forest. The model is used to assess the consequences of the harvest of commercial species from the complex notophyll vine forest both in terms of a single harvest and of a repeated harvest. The KIAMBRAM model predicts that repeated logging on a 30-year cycle would lead to rain forest in which cover was maintained but species composition altered. The composition would shift toward species of earlier successional stages, of lower value as logs. The volume available for harvest would be smaller. Application of the model to other tropical rain forests in discussed.

  18. Enigmatic declines in bird numbers in lowland forest of eastern Ecuador may be a consequence of climate change.

    PubMed

    Blake, John G; Loiselle, Bette A

    2015-01-01

    Bird populations have declined in many parts of the world but most of those declines can be attributed to effects of human activities (e.g., habitat fragmentation); declines in areas unaffected by human activities are not common. We have been sampling bird populations at an undisturbed site in lowland forest of eastern Ecuador annually since 2001 using a combination of mist nets and direct observations on two 100-ha plots. Bird numbers fluctuated on both plots during the first 8 years but did not show a consistent pattern of change. Since about 2008, numbers of birds on both plots have declined; capture rates in 2014 were ∼40% less than at the start of the study and observation rates were ∼50% less. Both understory and canopy species declined in abundance. Overall, insectivores showed the most pronounced declines but declines varied among trophic groups. The period from 2008 onward also was a period of stronger La Niña events which, at this study site, are associated with increased rainfall. The mechanism for the declines is not known but likely reflects a combination of reduced reproductive success coupled with reduced survival associated with changing climate. PMID:26339554

  19. Enigmatic declines in bird numbers in lowland forest of eastern Ecuador may be a consequence of climate change

    PubMed Central

    Loiselle, Bette A.

    2015-01-01

    Bird populations have declined in many parts of the world but most of those declines can be attributed to effects of human activities (e.g., habitat fragmentation); declines in areas unaffected by human activities are not common. We have been sampling bird populations at an undisturbed site in lowland forest of eastern Ecuador annually since 2001 using a combination of mist nets and direct observations on two 100-ha plots. Bird numbers fluctuated on both plots during the first 8 years but did not show a consistent pattern of change. Since about 2008, numbers of birds on both plots have declined; capture rates in 2014 were ∼40% less than at the start of the study and observation rates were ∼50% less. Both understory and canopy species declined in abundance. Overall, insectivores showed the most pronounced declines but declines varied among trophic groups. The period from 2008 onward also was a period of stronger La Niña events which, at this study site, are associated with increased rainfall. The mechanism for the declines is not known but likely reflects a combination of reduced reproductive success coupled with reduced survival associated with changing climate. PMID:26339554

  20. In situ survival of Vibrio cholerae and Escherichia coli in a tropical rain forest watershed.

    PubMed

    Pérez-Rosas, N; Hazen, T C

    1989-02-01

    For 12 months, Vibrio cholerae and fecal coliform densities were monitored along with nine other water quality parameters at 12 sites in a rain forest watershed in Puerto Rico. Densities of V. cholerae and fecal coliforms were not significantly correlated, even though the highest densities of both bacteria were found at a sewage outfall. High densities of V. cholerae were also found at pristine sites at the highest point in the watershed. The density of Escherichia coli and V. cholerae in membrane diffusion chambers did not change significantly during the course of two such studies. Physiological activity, as measured by electron transport system activity and relative nucleic acid composition, indicated that both E. coli and V. cholerae remained active. This study suggests that V. cholerae is indigenous to tropical fresh waters and that assays other than those that detect fecal coliforms or E. coli must be used for assessing public health risk in tropical waters.

  1. Multiple antibiotic resistant Escherichia coli from a tropical rain forest stream

    SciTech Connect

    Carrasco, C.E.; Alvarez, H.J.; Ortiz, N.; Bisbal, M.; Arias, W.; Baerga, C.; Hazen, T.C.

    1988-12-31

    High densities of fecal coliforms were obtained from a pristine site and sewage contaminated site in a tropical rain forest watershed in Puerto Rico. Confirmation of fecal coliform isolates as Escherichia coli was significantly lower than for temperate waters. Antibiotic resistance and multiple antibiotic resistance were common for isolates at both sites; however, the site receiving sewage effluent had a greater proportion of multiple antibiotic resistant isolates. R. plasmids were recovered from 4 MAR isolates, 2 from each site. All recovered plasmids were approximately 1 kilobase. The recovered plasmid were also capable of transforming E. coli HB101 in vitro. The high concentrations of enterobacteriaceae, small R-plasmid size, R-plasmid transformability, and long term survival of fecal origin bacteria in tropical freshwater environments give increasing importance to adequate sewage treatment, and better indicator monitoring methods for tropical areas.

  2. Yeast communities in two Atlantic rain Forest fragments in Southeast Brazil

    PubMed Central

    Pimenta, Raphael S.; Alves, Priscila D. D.; Almeida, Gabriel M. F.; Silva, Juliana F.M; Morais, Paula B.; Corrêa Jr., Ary; Rosa, Carlos A.

    2009-01-01

    We studied the yeast communities associated with fruits, mushrooms, tree exudates, and flies of the genus Drosophila, in two Atlantic Rain Forest fragments in state of Minas Gerais, Brazil. A total of 456 samples were collected from Rio Doce State Park and 142 from Ecological Station of Universidade Federal de Minas Gerais. From these samples, 608 yeast isolates were obtained, belonging to 71 different species. Among the yeasts isolated from Rio Doce State Park, 17 isolates were recovered from fruits, 12 from mushrooms, 13 from tree exudates, and 299 from Drosophila spp. In the Ecological Station of Universidade Federal de Minas Gerais, 24 isolates were recovered from fruits and 243 from Drosophila spp. Distinct communities of yeast were observed in Drosophila flies, fruits, mushrooms and tree exudates. The highest number of yeast species was recovered from Drosophila flies suggesting that flies are the natural vectors of these microorganisms. PMID:24031324

  3. In situ survival of Vibrio cholerae and Escherichia coli in a tropical rain forest watershed.

    PubMed Central

    Pérez-Rosas, N; Hazen, T C

    1989-01-01

    For 12 months, Vibrio cholerae and fecal coliform densities were monitored along with nine other water quality parameters at 12 sites in a rain forest watershed in Puerto Rico. Densities of V. cholerae and fecal coliforms were not significantly correlated, even though the highest densities of both bacteria were found at a sewage outfall. High densities of V. cholerae were also found at pristine sites at the highest point in the watershed. The density of Escherichia coli and V. cholerae in membrane diffusion chambers did not change significantly during the course of two such studies. Physiological activity, as measured by electron transport system activity and relative nucleic acid composition, indicated that both E. coli and V. cholerae remained active. This study suggests that V. cholerae is indigenous to tropical fresh waters and that assays other than those that detect fecal coliforms or E. coli must be used for assessing public health risk in tropical waters. PMID:2655536

  4. Assessment of organochlorine pesticide residues in Atlantic Rain Forest fragments, Rio de Janeiro, Brazil.

    PubMed

    Quinete, Natalia Soares; de Oliveira, Elba dos Santos; Fernandes, Daniella R; Avelar, Andre de Souza; Santelli, Ricardo Erthal

    2011-12-01

    A superficial water quality survey in a watershed of the Paraíba do Sul River, the main water supply for the most populated cities of southeastern Brazil, was held in order to assess the impact of the expansion of agricultural activity in the near border of the Atlantic Rain Forest. The aim of this study was to investigate the presence of priority organochlorine pollutants in soils and superficial waters of Atlantic rainforest fragments in Teresópolis, Rio de Janeiro State. Soil sample preparations were compared by using ultrasound, microwave assisted extraction and Soxhlet extraction. Recoveries of matrix spiked samples ranged from 70 to 130%. Analysis of a certified soil material showed recoveries ranging from 71 to 234%. Although low concentrations of organochlorine residues were found in water and soil samples, this area is of environmental importance and concern, thus demanding a monitoring program of its compartments. PMID:21864959

  5. Los Arboles Hablan: A Spanish Language Curriculum Unit Based on the Study of Latin American Rain Forests.

    ERIC Educational Resources Information Center

    Zuman, John P.

    "Los Arboles Hablan," a video-based curriculum that promotes the learning of Spanish as a second language through study of the Latin American rain forests is described. The 12-session unit was designed for use at the middle school level and integrates science, social science, and environmental education with content focusing on the Amazon rain…

  6. Do foliar, litter, and root nitrogen and phosphorus concentrations reflect nutrient limitation in a lowland tropical wet forest?

    PubMed

    Alvarez-Clare, Silvia; Mack, Michelle C

    2015-01-01

    Understanding nutrient limitation of net primary productivity (NPP) is critical to predict how plant communities will respond to environmental change. Foliar nutrients, especially nitrogen and phosphorus concentrations ([N] and [P]) and their ratio, have been used widely as indicators of plant nutritional status and have been linked directly to nutrient limitation of NPP. In tropical systems, however, a high number of confounding factors can limit the ability to predict nutrient limitation--as defined mechanistically by NPP responses to fertilization--based on the stoichiometric signal of the plant community. We used a long-term full factorial N and P fertilization experiment in a lowland tropical wet forest in Costa Rica to explore how tissue (foliar, litter and root) [N] and [P] changed with fertilization, how different tree size classes and taxa influenced the community response, and how tissue nutrients related to NPP. Consistent with NPP responses to fertilization, there were no changes in community-wide foliar [N] and [P], two years after fertilization. Nevertheless, litterfall [N] increased with N additions and root [P] increased with P additions. The most common tree species (Pentaclethra macroloba) had 9% higher mean foliar [N] with NP additions and the most common palm species (Socratea exohrriza) had 15% and 19% higher mean foliar [P] with P and NP additions, respectively. Moreover, N:P ratios were not indicative of NPP responses to fertilization, either at the community or at the taxa level. Our study suggests that in these diverse tropical forests, tissue [N] and [P] are driven by the interaction of multiple factors and are not always indicative of the nutritional status of the plant community. PMID:25901750

  7. Do Foliar, Litter, and Root Nitrogen and Phosphorus Concentrations Reflect Nutrient Limitation in a Lowland Tropical Wet Forest?

    PubMed Central

    Alvarez-Clare, Silvia; Mack, Michelle C.

    2015-01-01

    Understanding nutrient limitation of net primary productivity (NPP) is critical to predict how plant communities will respond to environmental change. Foliar nutrients, especially nitrogen and phosphorus concentrations ([N] and [P]) and their ratio, have been used widely as indicators of plant nutritional status and have been linked directly to nutrient limitation of NPP. In tropical systems, however, a high number of confounding factors can limit the ability to predict nutrient limitation —as defined mechanistically by NPP responses to fertilization— based on the stoichiometric signal of the plant community. We used a long-term full factorial N and P fertilization experiment in a lowland tropical wet forest in Costa Rica to explore how tissue (foliar, litter and root) [N] and [P] changed with fertilization, how different tree size classes and taxa influenced the community response, and how tissue nutrients related to NPP. Consistent with NPP responses to fertilization, there were no changes in community-wide foliar [N] and [P], two years after fertilization. Nevertheless, litterfall [N] increased with N additions and root [P] increased with P additions. The most common tree species (Pentaclethra macroloba) had 9 % higher mean foliar [N] with NP additions and the most common palm species (Socratea exohrriza) had 15% and 19% higher mean foliar [P] with P and NP additions, respectively. Moreover, N:P ratios were not indicative of NPP responses to fertilization, either at the community or at the taxa level. Our study suggests that in these diverse tropical forests, tissue [N] and [P] are driven by the interaction of multiple factors and are not always indicative of the nutritional status of the plant community. PMID:25901750

  8. Do foliar, litter, and root nitrogen and phosphorus concentrations reflect nutrient limitation in a lowland tropical wet forest?

    PubMed

    Alvarez-Clare, Silvia; Mack, Michelle C

    2015-01-01

    Understanding nutrient limitation of net primary productivity (NPP) is critical to predict how plant communities will respond to environmental change. Foliar nutrients, especially nitrogen and phosphorus concentrations ([N] and [P]) and their ratio, have been used widely as indicators of plant nutritional status and have been linked directly to nutrient limitation of NPP. In tropical systems, however, a high number of confounding factors can limit the ability to predict nutrient limitation--as defined mechanistically by NPP responses to fertilization--based on the stoichiometric signal of the plant community. We used a long-term full factorial N and P fertilization experiment in a lowland tropical wet forest in Costa Rica to explore how tissue (foliar, litter and root) [N] and [P] changed with fertilization, how different tree size classes and taxa influenced the community response, and how tissue nutrients related to NPP. Consistent with NPP responses to fertilization, there were no changes in community-wide foliar [N] and [P], two years after fertilization. Nevertheless, litterfall [N] increased with N additions and root [P] increased with P additions. The most common tree species (Pentaclethra macroloba) had 9% higher mean foliar [N] with NP additions and the most common palm species (Socratea exohrriza) had 15% and 19% higher mean foliar [P] with P and NP additions, respectively. Moreover, N:P ratios were not indicative of NPP responses to fertilization, either at the community or at the taxa level. Our study suggests that in these diverse tropical forests, tissue [N] and [P] are driven by the interaction of multiple factors and are not always indicative of the nutritional status of the plant community.

  9. Soil Nitrogen-Cycling Responses to Conversion of Lowland Forests to Oil Palm and Rubber Plantations in Sumatra, Indonesia.

    PubMed

    Allen, Kara; Corre, Marife D; Tjoa, Aiyen; Veldkamp, Edzo

    2015-01-01

    Rapid deforestation in Sumatra, Indonesia is presently occurring due to the expansion of palm oil and rubber production, fueled by an increasing global demand. Our study aimed to assess changes in soil-N cycling rates with conversion of forest to oil palm (Elaeis guineensis) and rubber (Hevea brasiliensis) plantations. In Jambi Province, Sumatra, Indonesia, we selected two soil landscapes - loam and clay Acrisol soils - each with four land-use types: lowland forest and forest with regenerating rubber (hereafter, "jungle rubber") as reference land uses, and rubber and oil palm as converted land uses. Gross soil-N cycling rates were measured using the 15N pool dilution technique with in-situ incubation of soil cores. In the loam Acrisol soil, where fertility was low, microbial biomass, gross N mineralization and NH4+ immobilization were also low and no significant changes were detected with land-use conversion. The clay Acrisol soil which had higher initial fertility based on the reference land uses (i.e. higher pH, organic C, total N, effective cation exchange capacity (ECEC) and base saturation) (P≤0.05-0.09) had larger microbial biomass and NH4+ transformation rates (P≤0.05) compared to the loam Acrisol soil. Conversion of forest and jungle rubber to rubber and oil palm in the clay Acrisol soil decreased soil fertility which, in turn, reduced microbial biomass and consequently decreased NH4+ transformation rates (P≤0.05-0.09). This was further attested by the correlation of gross N mineralization and microbial biomass N with ECEC, organic C, total N (R=0.51-0. 76; P≤0.05) and C:N ratio (R=-0.71 - -0.75, P≤0.05). Our findings suggest that the larger the initial soil fertility and N availability, the larger the reductions upon land-use conversion. Because soil N availability was dependent on microbial biomass, management practices in converted oil palm and rubber plantations should focus on enriching microbial biomass.

  10. Soil Nitrogen-Cycling Responses to Conversion of Lowland Forests to Oil Palm and Rubber Plantations in Sumatra, Indonesia.

    PubMed

    Allen, Kara; Corre, Marife D; Tjoa, Aiyen; Veldkamp, Edzo

    2015-01-01

    Rapid deforestation in Sumatra, Indonesia is presently occurring due to the expansion of palm oil and rubber production, fueled by an increasing global demand. Our study aimed to assess changes in soil-N cycling rates with conversion of forest to oil palm (Elaeis guineensis) and rubber (Hevea brasiliensis) plantations. In Jambi Province, Sumatra, Indonesia, we selected two soil landscapes - loam and clay Acrisol soils - each with four land-use types: lowland forest and forest with regenerating rubber (hereafter, "jungle rubber") as reference land uses, and rubber and oil palm as converted land uses. Gross soil-N cycling rates were measured using the 15N pool dilution technique with in-situ incubation of soil cores. In the loam Acrisol soil, where fertility was low, microbial biomass, gross N mineralization and NH4+ immobilization were also low and no significant changes were detected with land-use conversion. The clay Acrisol soil which had higher initial fertility based on the reference land uses (i.e. higher pH, organic C, total N, effective cation exchange capacity (ECEC) and base saturation) (P≤0.05-0.09) had larger microbial biomass and NH4+ transformation rates (P≤0.05) compared to the loam Acrisol soil. Conversion of forest and jungle rubber to rubber and oil palm in the clay Acrisol soil decreased soil fertility which, in turn, reduced microbial biomass and consequently decreased NH4+ transformation rates (P≤0.05-0.09). This was further attested by the correlation of gross N mineralization and microbial biomass N with ECEC, organic C, total N (R=0.51-0. 76; P≤0.05) and C:N ratio (R=-0.71 - -0.75, P≤0.05). Our findings suggest that the larger the initial soil fertility and N availability, the larger the reductions upon land-use conversion. Because soil N availability was dependent on microbial biomass, management practices in converted oil palm and rubber plantations should focus on enriching microbial biomass. PMID:26222690

  11. Interspecific variation in leaf litter tannins drives decomposition in a tropical rain forest of French Guiana.

    PubMed

    Coq, Sylvain; Souquet, Jean-Marc; Meudec, Emmanuelle; Cheynier, Véronique; Hättenschwiler, Stephan

    2010-07-01

    Tannins are believed to be particularly abundant in tropical tree foliage and are mainly associated with plant herbivore defense. Very little is known of the quantity, variation, and potential role of tannins in tropical leaf litter. Here we report on the interspecific variability of litter condensed tannin (CT) concentration among 16 co-occurring tropical rain forest tree species of French Guiana and explore the functional significance of variable litter CT concentration for litter decomposition. We compared some classical methods in the ecological literature to a method based on high-performance liquid chromatography (HPLC), coupled with CT degradation by phloroglucinolysis. The same litter was allowed to decompose in the field in the presence or absence of soil fauna. We found large interspecific differences in the average polymerization degree (2.7 to 21.3, for non-extractable CT) and concentration of litter CT (0-3.7% dry mass, for total CT) determined by HPLC, which did not correlate with Folin total phenolics but correlated reasonably well with acid butanol CT. The concentration and polymerization degree of HPLC-determined CT were the only variables of the multitude of measured initial litter quality parameters that explained a significant amount of variation in litter mass loss among species, irrespective of animal presence. However, animal presence increased mean litter mass loss by a factor of 1.5, and the fauna effect on decomposition was best explained by a negative correlation with total HPLC CT and by a positive correlation with hemicellulose. Our results suggest that the commonly used acid butanol assay yields a reliable estimate of interspecific variation in CT concentration. However, the chemical structure of CTs, such as the polymerization degree, adds important information for the understanding of the functional role of CTs in litter decomposition. We conclude that the wide variation in structure and concentration of leaf litter CTs among

  12. A framework for assessment and monitoring of small mammals in a lowland tropical forest.

    PubMed

    Solari, Sergio; Rodriguez, Juan José; Vivar, Elena; Velazco, Paul M

    2002-05-01

    Development projects in tropical forests can impact biodiversity. Assessment and monitoring programs based on the principles of adaptive management assist managers to identify and reduce such impacts. The small mammal community is one important component of a forest ecosystem that may be impacted by development projects. In 1996, a natural gas exploration project was initiated in a Peruvian rainforest. The Smithsonian Institution's Monitoring and Assessment of Biodiversity program cooperated with Shell Prospecting and Development Peru to establish an adaptive management program to protect the region's biodiversity. In this article, we discuss the role of assessing and monitoring small mammals in relation to the natural gas project. We outline the conceptual issues involved in establishing an assessment and monitoring program, including setting objectives, evaluating the results and making appropriate decisions. We also summarize the steps taken to implement the small mammal assessment, provide results from the assessment and discuss protocols to identify appropriate species for monitoring. PMID:12125752

  13. Tiger density in a tropical lowland forest in the Eastern Himalayan Mountains.

    PubMed

    Singh, Randeep; Chauhan, Devendra Singh; Mishra, Sudhanshu; Krausman, Paul R; Goyal, Surendra Prakash

    2014-01-01

    Tropical evergreen forests in northeast India are a biological hot spot for conservation of flora and fauna. Little is known, however, about tiger abundance, which is a flagship species for tropical evergreen forests. Our objective was to document the capture rate and population density of tigers based on spatial explicit capture-recapture (SECR) approaches using camera trap data in an intensive study area (ISA) of 158 km(2) in Pakke Tiger Reserve (PTR) during March to May 2006. The Reserve lies in the foothills of the Eastern Himalayan Mountains, northeast India. We monitored 38 camera traps in ISA for 70 days and documented 10 photo-captures of tigers (5 left and 5 right flanks) with an average trap success rate of 1.3 captures/100 trap days. The overall capture probability was 0.05. The tiger density estimated using a SECR model was 0.97 ± 0.23 individuals/100 km(2). This is the first systematic sampling study in tropical semi evergreen forests of India, and information on capture rate and population density of tigers provides baseline data from which to determining changes in the future to assist conservation. PMID:25187884

  14. Nitrogen cycling in a northern forest: Gases to clouds to rain

    NASA Astrophysics Data System (ADS)

    Hill, Kimberly Ann

    In a forest environment, many processes alter the amount and type of nitrogen that deposits by wet and dry deposition to the forest floor. Gas-phase chemistry changes what compounds are available to be scavenged by cloud and rain droplets as well as to dry-deposit to the leaves. Cloud chemistry and microbes in the cloud water alter which compounds may go back into the gas-phase or wet deposit to the surface. Processing of dry-deposited nitrogen species on leaf surfaces changes the nitrogen washed off by rainwater as it passes through the forest canopy. In this thesis, measurements of the inorganic and organic nitrogen composition of precipitation both under the forest canopy and in an open field at the University of Michigan Biological Station are described. The data collected showed that the nitrate and organic nitrogen concentrations were substantially enhanced by interaction with the forest canopy, while ammonium concentrations were slightly decreased. Wash off of dry-deposited nitric acid and particulate nitrate was determined to be the likely source of the enhanced nitrate concentration, although some of the deposited nitric acid was either taken up by the canopy or revolatilized back into the atmosphere. Cloud water collected over the forested area of the northern section of the lower peninsula of Michigan and analyzed for inorganic and organic nitrogen content showed a significant fraction of the nitrogen was organic. Although relatively large concentrations of bacteria existed in the clouds, they contributed insignificant amounts of nitrogen to the cloud water. However, the bacteria have the potential to alter the nitrogen composition, as nitrifiers were identified in the samples. Finally, the development of an NO chemiluminescence analyzer with NO2 and NOy inlets and thermal dissociation inlets to study total reactive odd-nitrogen (NO y) and the individual species that compose NOy(NOx, organic nitrates, peroxyacyl nitrates, and nitric acid) are described

  15. [Relationships between soil moisture and needle-fall in Masson pine forests in acid rain region of Chongqing, Southwest China].

    PubMed

    Wang, Yi-Hao; Wang, Yan-Hui; Li, Zhen-Hua; Yu, Peng-Tao; Xiong, Wei; Hao, Jia; Duan, Jian

    2012-10-01

    From March 2009 to November 2011, an investigation was conducted on the spatiotemporal variation of soil moisture and its effects on the needle-fall in Masson pine (Pinus massoniana) forests in acid rain region of Chongqing, Southeast China, with the corresponding soil moisture thresholds determined. No matter the annual precipitation was abundant, normal or less than average, the seasonal variation of soil moisture in the forests could be obviously divided into four periods, i.e., sufficient (before May), descending (from June to July), drought (from August to September), and recovering (from October to November). With increasing soil depth, the soil moisture content increased after an initial decrease, but the difference of the soil moisture content among different soil layers decreased with decreasing annual precipitation. The amount of monthly needle-fall in the forests in growth season was significantly correlated with the water storage in root zone (0-60 cm soil layer), especially in the main root zone (20-50 cm soil layer). Soil field capacity (or capillary porosity) and 82% of field capacity (or 80% of capillary porosity) were the main soil moisture thresholds affecting the litter-fall. It was suggested that in acid rain region, Masson pine forest was easily to suffer from water deficit stress, especially in dry-summer period. The water deficit stress, together with already existed acid rain stress, would further threaten the health of the Masson forest.

  16. OH observations in a tropical rain forest environment using a chemical ionization mass spectrometry technique during GOAmazon intensive campaigns

    NASA Astrophysics Data System (ADS)

    Kim, S.; Seco, R.; Park, J. H.; Sjostedt, S. J.; Guenther, A. B.; Smith, J. N.; Liu, Y.; Bustillos, J. O. V.; Souza, R. A. F. D.; Tota, J.; Martin, S. T.

    2015-12-01

    We will present observed OH in the Amazon rain forest using a chemical ionization mass spectrometer (CIMS). The observation was conducted at the T3 site in Manacapuru, Amazonas Brazil. It had been accepted almost as an axiom that very low OH is expected in low NO environments such as a pristine rain forest. However, recent studies in the pristine rain forest environments consistently reported significantly higher than expected OH levels. This sparked extensive and intensive studies to explore any possibility of OH regeneration from isoprene photo-oxidation processes in the low NO condition. Four OH regeneration processes related with isoprene photochemistry have been proposed since 2008. However, the levels of the expected OH enhancement vary greatly among the proposed OH regeneration processes mediated by the isoprene oxidation processes. As all enhanced OH observations from the pristine areas with high isoprene conditions have used the laser induced fluorescence (LIF) technique, the possibilities of potential positive artifacts have also been explored. In this context, the first tropical forest CIMS OH dataset will be discussed in the context of 1) comparisons with previously reported OH using the LIF technique, 2) comparisons with box model calculated OH with different isoprene oxidation scenarios to reconcile measured and calculated OH, and 3) comparisons with regional model calculated OH. The CIMS observational dataset along with a comprehensive trace gas dataset provides a constraint to assess current uncertainty in oxidation capacity of the pristine forested region, which has tremendous implications towards global fates of short lived climate forcers.

  17. [Relationships between soil moisture and needle-fall in Masson pine forests in acid rain region of Chongqing, Southwest China].

    PubMed

    Wang, Yi-Hao; Wang, Yan-Hui; Li, Zhen-Hua; Yu, Peng-Tao; Xiong, Wei; Hao, Jia; Duan, Jian

    2012-10-01

    From March 2009 to November 2011, an investigation was conducted on the spatiotemporal variation of soil moisture and its effects on the needle-fall in Masson pine (Pinus massoniana) forests in acid rain region of Chongqing, Southeast China, with the corresponding soil moisture thresholds determined. No matter the annual precipitation was abundant, normal or less than average, the seasonal variation of soil moisture in the forests could be obviously divided into four periods, i.e., sufficient (before May), descending (from June to July), drought (from August to September), and recovering (from October to November). With increasing soil depth, the soil moisture content increased after an initial decrease, but the difference of the soil moisture content among different soil layers decreased with decreasing annual precipitation. The amount of monthly needle-fall in the forests in growth season was significantly correlated with the water storage in root zone (0-60 cm soil layer), especially in the main root zone (20-50 cm soil layer). Soil field capacity (or capillary porosity) and 82% of field capacity (or 80% of capillary porosity) were the main soil moisture thresholds affecting the litter-fall. It was suggested that in acid rain region, Masson pine forest was easily to suffer from water deficit stress, especially in dry-summer period. The water deficit stress, together with already existed acid rain stress, would further threaten the health of the Masson forest. PMID:23359920

  18. Seedling mortality in Hawaiian rain forest: The role of small-scale physical disturbance

    USGS Publications Warehouse

    Drake, D.R.; Pratt, L.W.

    2001-01-01

    Most montane rain forests on the island of Hawaii consist of a closed canopy formed by Cibotium spp. tree ferns beneath an open canopy of emergent Metrosideros polymorpha trees. We used artificial seedlings to assess the extent to which physical disturbance caused by the senescing fronds of tree ferns and the activities of feral pigs might limit tree regeneration. Artificial seedlings were established terrestrially (N = 300) or epiphytically (N = 300) on tree fern stems. Half of the seedlings on each substrate were in an exclosure lacking feral pigs and half were in forest with pigs present. After one year, the percentage of seedlings damaged was significantly greater among terrestrial seedlings (25.7%) than epiphytic seedlings (11.3%). Significantly more terrestrial seedlings were damaged in the presence of pigs (31.3%) than in the absence of pigs (20.0%). Senescing fronds of tree ferns were responsible for 60.3 percent of the damaged seedlings. Physical disturbance is potentially a major cause of seedling mortality and may reduce the expected half-life of a seedling cohort to less than two years.

  19. Connectivity of overland flow by drainage network expansion in a rain forest catchment

    NASA Astrophysics Data System (ADS)

    Zimmermann, Beate; Zimmermann, Alexander; Turner, Benjamin L.; Francke, Till; Elsenbeer, Helmut

    2014-02-01

    Soils in various places of the Panama Canal Watershed feature a low saturated hydraulic conductivity (Ks) at shallow depth, which promotes overland-flow generation and associated flashy catchment responses. In undisturbed forests of these areas, overland flow is concentrated in flow lines that extend the channel network and provide hydrological connectivity between hillslopes and streams. To understand the dynamics of overland-flow connectivity, as well as the impact of connectivity on catchment response, we studied an undisturbed headwater catchment by monitoring overland-flow occurrence in all flow lines and discharge, suspended sediment, and total phosphorus at the catchment outlet. We find that connectivity is strongly influenced by seasonal variation in antecedent wetness and can develop even under light rainfall conditions. Connectivity increased rapidly as rainfall frequency increased, eventually leading to full connectivity and surficial drainage of entire hillslopes. Connectivity was nonlinearly related to catchment response. However, additional information on factors such as overland-flow volume would be required to constrain relationships between connectivity, stormflow, and the export of suspended sediment and phosphorus. The effort to monitor those factors would be substantial, so we advocate applying the established links between rain event characteristics, drainage network expansion by flow lines, and catchment response for predictive modeling and catchment classification in forests of the Panama Canal Watershed and in similar regions elsewhere.

  20. Patch network criteria for dispersal-limited endemic birds of South American temperate rain forest.

    PubMed

    Castellón, Traci D; Sieving, Kathryn E

    2007-12-01

    We developed a set of simple empirically based criteria for distinguishing forest patch configurations that we expected to support persistent populations of two endemic Tapaculo species with limited dispersal ability (Chucao Tapaculos [Scelorchilus rubecula] and Black-throated Huet-huets [Pteroptochos tarnii]) in South American temperate rain forest. The criteria address sustainable population sizes (tested using population viability analysis), habitat area needed to support sustainable populations, and measures of functional connectivity derived from radiotelemetry data and patch occupancy models. We then applied the criteria in three real-world demonstration landscapes, first, to predict numbers of breeding territories potentially accommodated within patch configurations and, second, to evaluate increases that might be achieved if landscape connections among isolated patches were restored (e.g., using corridors). The best connected of the three demonstration landscapes was predicted to support large sustainable populations without intervention to restore connectivity, whereas none of the patch configurations was sustainable in the most fragmented landscape, with or without corridor restoration. Notably, however, corridor restoration in the landscape with an intermediate fragmentation level was expected to quadruple the sustainable Chucao population and potentially prevent regional Huet-huet extinction. Thus, our network criteria provide a simple approach for developing and evaluating spatially explicit prescriptions for conservation planning in this highly endangered biome. The criteria may be especially useful for discriminating among landscapes where restoration of connectivity is, or is not, an appropriate course of action.

  1. Effect of Forest Age on Rainwater Infiltration in the Lowland Humid Tropics

    NASA Astrophysics Data System (ADS)

    Kempema, E. W.; Mojica, A.; Litt, G.; Carey, A. M.; Ogden, F. L.

    2015-12-01

    We are working in the headwaters of the Rio Agua Salud catchment in central Panama to test the hypothesis that varying land uses, including time since afforestation, have significant impacts on rainfall infiltration, runoff generation and groundwater recharge. Increased infiltration and groundwater recharge during the wet season may result in increased groundwater flow during the dry season, the "sponge effect hypothesis". We irrigate a 6m by 2m test plot with slightly saline water at varying applied rainfall intensities using an ARS-type rainfall simulator, which has an oscillating boom mounted 2m above the forest floor, and four spray nozzles. We install 10cm tall lawn edging at the bottom of the test plot to direct surface water runoff to a small flume where runoff rates are recorded over time. In addition, we use time lapse ERI (electrical resistivity imaging) to map the vertical and downslope flow paths. We add NaCl to the applied water at a concentration of 200 mg/l, tagged with 10 mg/l LiBr as a salinity/conductivity contrast. Because ERI is highly sensitivity to changes in the electrical conductivity of soils and solute, we obtain a clear time-lapse image of flow path and bulk flow velocities. In this presentation we compare and contrast results of observations collected in an actively grazed cattle pasture adjacent ~10-12 year and >25 year old secondary forest plots using data collected during the 2015 wet season.

  2. Influence of lowland forests on subsurface salt accumulation in shallow groundwater areas

    PubMed Central

    Tóth, Tibor; Balog, Kitti; Szabó, András; Pásztor, László; Jobbágy, Esteban G.; Nosetto, Marcelo D.; Gribovszki, Zoltán

    2013-01-01

    In flat sedimentary plains in areas with a sub-humid climate, tree planting on grasslands and arable lands creates strong hydrological shifts. As a result of deep rooting and high water uptake of trees, groundwater levels drop and subsurface salt accumulation increases. Tree planting has expanded globally and in Hungary it reached rates of 15 000 ha year−1, being focused mainly in the Great Hungarian Plain where forests replace grasslands and crops in a region with widespread shallow groundwater. We performed soil and groundwater observations in 31 pairs of forest and control plots in the region, including gradients of initial water table depth and salinity, soil layering, and tree species and age. Accumulated tree biomass was positively correlated with soil salinization rates following tree planting, being also affected by species (poplar > common oak > black locust) and stand age. Differences among tree species effects appeared to be related to their growth rates. Due to downward deep percolation and salt leaching episodes during the Hungarian winters, the observed salt accumulation rates were lower than those described under similar settings in the warmer Argentine Pampas. PMID:25228311

  3. Variation in photosynthetic light-use efficiency in a mountainous tropical rain forest in Indonesia.

    PubMed

    Ibrom, Andreas; Oltchev, Alexander; June, Tania; Kreilein, Heiner; Rakkibu, Golam; Ross, Thomas; Panferov, Oleg; Gravenhorst, Gode

    2008-04-01

    Photosynthetically active radiation (Q)-use efficiency (epsilon) is an important parameter for deriving carbon fluxes between forest canopies and the atmosphere from meteorological ground and remote sensing data. A common approach is to assume gross primary production (P(g)) and net primary production (P(n)) are proportional to Q absorbed by vegetation (Q(abs)) by defining the proportionality constants epsilon(Pg) and epsilon(Pn) (for P(g) and P(n), respectively). Although remote sensing and climate monitoring provide Q(abs) and other meteorological data at the global scale, information on epsilon is particularly scarce in remote tropical areas. We used a 16-month continuous CO(2) flux and meteorological dataset from a mountainous tropical rain forest in central Sulawesi, Indonesia to derive values of epsilon(Pg) and to investigate the relationship between P(g) and Q(abs). Absorption was estimated with a 1D SVAT model from measured canopy structure and short wave radiation. The half-hourly P(g) data showed a saturation response to Q(abs). The amount of Q(abs) required to saturate P(g) was reduced when water vapor saturation deficit (D) was high. Light saturation of P(g) was still evident when shifting from half-hourly to daily and monthly time scales. Thus, for a majority of observations, P(g) was insensitive to changes in Q(abs). A large proportion of the observed seasonal variability in P(g) could not be attributed to changes in Q(abs) or D. Values of epsilon(Pg) varied little around the long-term mean of 0.0179 mol CO(2) (mol photon)(-1) or 0.99 g C MJ(-1) (the standard deviations were +/- 0.006 and +/- 0.0018 mol CO(2) (mol photon)(-1) for daily and monthly means, respectively). In both cases, epsilon(Pg) values were more sensitive to Q(abs) than to daytime D. These findings show that the current epsilon-approaches fail to predict P(g) at our tropical rain forest site for two reasons: (1) they neglect saturation of P(g) when Q(abs) is high; and (2) they do not

  4. Optimal Wavelength Selection on Hyperspectral Data with Fused Lasso for Biomass Estimation of Tropical Rain Forest

    NASA Astrophysics Data System (ADS)

    Takayama, T.; Iwasaki, A.

    2016-06-01

    Above-ground biomass prediction of tropical rain forest using remote sensing data is of paramount importance to continuous large-area forest monitoring. Hyperspectral data can provide rich spectral information for the biomass prediction; however, the prediction accuracy is affected by a small-sample-size problem, which widely exists as overfitting in using high dimensional data where the number of training samples is smaller than the dimensionality of the samples due to limitation of require time, cost, and human resources for field surveys. A common approach to addressing this problem is reducing the dimensionality of dataset. Also, acquired hyperspectral data usually have low signal-to-noise ratio due to a narrow bandwidth and local or global shifts of peaks due to instrumental instability or small differences in considering practical measurement conditions. In this work, we propose a methodology based on fused lasso regression that select optimal bands for the biomass prediction model with encouraging sparsity and grouping, which solves the small-sample-size problem by the dimensionality reduction from the sparsity and the noise and peak shift problem by the grouping. The prediction model provided higher accuracy with root-mean-square error (RMSE) of 66.16 t/ha in the cross-validation than other methods; multiple linear analysis, partial least squares regression, and lasso regression. Furthermore, fusion of spectral and spatial information derived from texture index increased the prediction accuracy with RMSE of 62.62 t/ha. This analysis proves efficiency of fused lasso and image texture in biomass estimation of tropical forests.

  5. Low abundance of long-tongued pollinators leads to pollen limitation in four specialized hawkmoth-pollinated plants in the Atlantic Rain forest, Brazil

    NASA Astrophysics Data System (ADS)

    Amorim, Felipe W.; Wyatt, Graham E.; Sazima, Marlies

    2014-09-01

    Long-tubed hawkmoth-pollinated species present some of the most remarkable examples of floral specialization depending exclusively on long-tongued hawkmoths for sexual reproduction. Nonetheless, long-tongued hawkmoths do not rely exclusively on specialized plants as nectar sources, which may limit sexual reproduction through pollen limitation. However, very few studies have quantified the level of pollen limitation in plants with highly specialized floral traits in tropical regions. In this context, we studied four sympatric hawkmoth-pollinated species in a highland Atlantic Rain forest and assessed pollen limitation and their dependence on pollinators by analyzing the floral biology, breeding system, pollination mechanisms, and abundance of long-tongued pollinators. We showed that the four species are self-compatible, but are completely dependent on long-tongued hawkmoths to set fruits, and that flower visitation was infrequent in all plant species. Pollen limitation indices ranged from 0.53 to 0.96 showing that fruit set is highly limited by pollen receipt. Long-tongued moths are much less abundant and comprise only one sixth of the hawkmoth fauna. Pollen analyses of 578 sampled moths revealed that hawkmoths visited ca. 80 plant species in the community, but only two of the four species studied. Visited plants included a long-tubed hawkmoth-pollinated species endemic to the lowland forest ca. 15-20 km away from the study site. Specialization index (H 2 ' = 0.20) showed that community-level interactions between hawkmoths and plants are generalized. We suggest that sexual reproduction of these highly specialized hawkmoth-pollinated species is impaired by competition among plants for pollinators, in conjunction with the low abundance and diversity of long-tongued pollinators.

  6. Low abundance of long-tongued pollinators leads to pollen limitation in four specialized hawkmoth-pollinated plants in the Atlantic Rain forest, Brazil

    NASA Astrophysics Data System (ADS)

    Amorim, Felipe W.; Wyatt, Graham E.; Sazima, Marlies

    2014-11-01

    Long-tubed hawkmoth-pollinated species present some of the most remarkable examples of floral specialization depending exclusively on long-tongued hawkmoths for sexual reproduction. Nonetheless, long-tongued hawkmoths do not rely exclusively on specialized plants as nectar sources, which may limit sexual reproduction through pollen limitation. However, very few studies have quantified the level of pollen limitation in plants with highly specialized floral traits in tropical regions. In this context, we studied four sympatric hawkmoth-pollinated species in a highland Atlantic Rain forest and assessed pollen limitation and their dependence on pollinators by analyzing the floral biology, breeding system, pollination mechanisms, and abundance of long-tongued pollinators. We showed that the four species are self-compatible, but are completely dependent on long-tongued hawkmoths to set fruits, and that flower visitation was infrequent in all plant species. Pollen limitation indices ranged from 0.53 to 0.96 showing that fruit set is highly limited by pollen receipt. Long-tongued moths are much less abundant and comprise only one sixth of the hawkmoth fauna. Pollen analyses of 578 sampled moths revealed that hawkmoths visited ca. 80 plant species in the community, but only two of the four species studied. Visited plants included a long-tubed hawkmoth-pollinated species endemic to the lowland forest ca. 15-20 km away from the study site. Specialization index ( H 2 ' = 0.20) showed that community-level interactions between hawkmoths and plants are generalized. We suggest that sexual reproduction of these highly specialized hawkmoth-pollinated species is impaired by competition among plants for pollinators, in conjunction with the low abundance and diversity of long-tongued pollinators.

  7. Low abundance of long-tongued pollinators leads to pollen limitation in four specialized hawkmoth-pollinated plants in the Atlantic Rain forest, Brazil.

    PubMed

    Amorim, Felipe W; Wyatt, Graham E; Sazima, Marlies

    2014-11-01

    Long-tubed hawkmoth-pollinated species present some of the most remarkable examples of floral specialization depending exclusively on long-tongued hawkmoths for sexual reproduction. Nonetheless, long-tongued hawkmoths do not rely exclusively on specialized plants as nectar sources, which may limit sexual reproduction through pollen limitation. However, very few studies have quantified the level of pollen limitation in plants with highly specialized floral traits in tropical regions. In this context, we studied four sympatric hawkmoth-pollinated species in a highland Atlantic Rain forest and assessed pollen limitation and their dependence on pollinators by analyzing the floral biology, breeding system, pollination mechanisms, and abundance of long-tongued pollinators. We showed that the four species are self-compatible, but are completely dependent on long-tongued hawkmoths to set fruits, and that flower visitation was infrequent in all plant species. Pollen limitation indices ranged from 0.53 to 0.96 showing that fruit set is highly limited by pollen receipt. Long-tongued moths are much less abundant and comprise only one sixth of the hawkmoth fauna. Pollen analyses of 578 sampled moths revealed that hawkmoths visited ca. 80 plant species in the community, but only two of the four species studied. Visited plants included a long-tubed hawkmoth-pollinated species endemic to the lowland forest ca. 15-20 km away from the study site. Specialization index (H 2 ' = 0.20) showed that community-level interactions between hawkmoths and plants are generalized. We suggest that sexual reproduction of these highly specialized hawkmoth-pollinated species is impaired by competition among plants for pollinators, in conjunction with the low abundance and diversity of long-tongued pollinators.

  8. Low abundance of long-tongued pollinators leads to pollen limitation in four specialized hawkmoth-pollinated plants in the Atlantic Rain forest, Brazil.

    PubMed

    Amorim, Felipe W; Wyatt, Graham E; Sazima, Marlies

    2014-11-01

    Long-tubed hawkmoth-pollinated species present some of the most remarkable examples of floral specialization depending exclusively on long-tongued hawkmoths for sexual reproduction. Nonetheless, long-tongued hawkmoths do not rely exclusively on specialized plants as nectar sources, which may limit sexual reproduction through pollen limitation. However, very few studies have quantified the level of pollen limitation in plants with highly specialized floral traits in tropical regions. In this context, we studied four sympatric hawkmoth-pollinated species in a highland Atlantic Rain forest and assessed pollen limitation and their dependence on pollinators by analyzing the floral biology, breeding system, pollination mechanisms, and abundance of long-tongued pollinators. We showed that the four species are self-compatible, but are completely dependent on long-tongued hawkmoths to set fruits, and that flower visitation was infrequent in all plant species. Pollen limitation indices ranged from 0.53 to 0.96 showing that fruit set is highly limited by pollen receipt. Long-tongued moths are much less abundant and comprise only one sixth of the hawkmoth fauna. Pollen analyses of 578 sampled moths revealed that hawkmoths visited ca. 80 plant species in the community, but only two of the four species studied. Visited plants included a long-tubed hawkmoth-pollinated species endemic to the lowland forest ca. 15-20 km away from the study site. Specialization index (H 2 ' = 0.20) showed that community-level interactions between hawkmoths and plants are generalized. We suggest that sexual reproduction of these highly specialized hawkmoth-pollinated species is impaired by competition among plants for pollinators, in conjunction with the low abundance and diversity of long-tongued pollinators. PMID:25204723

  9. Aboveground and belowground effects of single-tree removals in New Zealand rain forest.

    PubMed

    Wardle, David A; Wiser, Susan K; Allen, Robert B; Doherty, James E; Bonner, Karen I; Williamson, Wendy M

    2008-05-01

    There has been considerable recent interest in how human-induced species loss affects community and ecosystem properties. These effects are particularly apparent when a commercially valuable species is harvested from an ecosystem, such as occurs through single-tree harvesting or selective logging of desired timber species in natural forests. In New Zealand mixed-species rain forests, single-tree harvesting of the emergent gymnosperm Dacrydium cupressinum, or rimu, has been widespread. This harvesting has been contentious in part because of possible ecological impacts of Dacrydium removal on the remainder of the forest, but many of these effects remain unexplored. We identified an area where an unintended 40-year "removal experiment" had been set up that involved selective extraction of individual Dacrydium trees. We measured aboveground and belowground variables at set distances from both individual live trees and stumps of trees harvested 40 years ago. Live trees had effects both above and below ground by affecting diversity and cover of several components of the vegetation (usually negatively), promoting soil C sequestration, enhancing ratios of soil C:P and N:P, and affecting community structure of soil microflora. These effects extended to 8 m from the tree base and were likely caused by poor-quality litter and humus produced by the trees. Measurements for the stumps revealed strong legacy effects of prior presence of trees on some properties (e.g., cover by understory herbs and ferns, soil C sequestration, soil C:P and N:P ratios), but not others (e.g., soil fungal biomass, soil N concentration). These results suggest that the legacy of prior presence of Dacrydium may remain for several decades or centuries, and certainly well over 40 years. They also demonstrate that, while large Dacrydium individuals (and their removal) may have important effects in their immediate proximity, within a forest, these effects should only be important in localized patches

  10. Health assessment of wild lowland tapir (Tapirus terrestris) populations in the Atlantic Forest and Pantanal biomes, Brazil (1996-2012).

    PubMed

    Medici, Emília Patrícia; Mangini, Paulo Rogerio; Fernandes-Santos, Renata Carolina

    2014-10-01

    Abstract The lowland tapir (Tapirus terrestris) is found in South America and is listed as Vulnerable to Extinction by the International Union for Conservation of Nature, Red List of Threatened Species. Health issues, particularly infectious diseases, are potential threats for the species. Health information from 65 wild tapirs from two Brazilian biomes, Atlantic Forest (AF) and Pantanal (PA), were collected during a long-term study (1996-2012). The study included physic, hematologic and biochemical evaluations, microbiologic cultures, urinalysis, and serologic analyses for antibodies against 13 infectious agents (viral and bacterial). The AF and PA tapirs were significantly different for several hematologic and biochemical parameters. Ten bacteria taxa were identified in the AF and 26 in the PA. Antibodies against five viruses were detected: Bluetongue virus, eastern equine encephalitis virus, western equine encephalitis virus, infectious bovine rhinotracheitis virus, and porcine parvovirus. A high prevalence of exposure to Leptospira interrogans (10 serovars: Autumnalis, Bratislava, Canicola, Copenhageni, Grippotyphosa, Hardjo, Hebdomadis, Icterohaemorrhagiae, Pomona, and Pyrogenes) was detected in both the AF and PA sites. A greater diversity of serovars and higher antibody titers were found in the PA. Statistically significant differences between sites were found for L. interrogans, equine encephalitis virus, and porcine parvovirus. Based on physical evaluations, both AF and PA populations were healthy. The differences in the overall health profile of the AF and PA tapir populations appear to be associated with environmental factors and infectious diseases ecology. The extensive datasets on hematology, biochemistry, urinalysis, and microbiology results from this paper can be used as reference values for wild tapirs. PMID:25105810

  11. Health assessment of wild lowland tapir (Tapirus terrestris) populations in the Atlantic Forest and Pantanal biomes, Brazil (1996-2012).

    PubMed

    Medici, Emília Patrícia; Mangini, Paulo Rogerio; Fernandes-Santos, Renata Carolina

    2014-10-01

    Abstract The lowland tapir (Tapirus terrestris) is found in South America and is listed as Vulnerable to Extinction by the International Union for Conservation of Nature, Red List of Threatened Species. Health issues, particularly infectious diseases, are potential threats for the species. Health information from 65 wild tapirs from two Brazilian biomes, Atlantic Forest (AF) and Pantanal (PA), were collected during a long-term study (1996-2012). The study included physic, hematologic and biochemical evaluations, microbiologic cultures, urinalysis, and serologic analyses for antibodies against 13 infectious agents (viral and bacterial). The AF and PA tapirs were significantly different for several hematologic and biochemical parameters. Ten bacteria taxa were identified in the AF and 26 in the PA. Antibodies against five viruses were detected: Bluetongue virus, eastern equine encephalitis virus, western equine encephalitis virus, infectious bovine rhinotracheitis virus, and porcine parvovirus. A high prevalence of exposure to Leptospira interrogans (10 serovars: Autumnalis, Bratislava, Canicola, Copenhageni, Grippotyphosa, Hardjo, Hebdomadis, Icterohaemorrhagiae, Pomona, and Pyrogenes) was detected in both the AF and PA sites. A greater diversity of serovars and higher antibody titers were found in the PA. Statistically significant differences between sites were found for L. interrogans, equine encephalitis virus, and porcine parvovirus. Based on physical evaluations, both AF and PA populations were healthy. The differences in the overall health profile of the AF and PA tapir populations appear to be associated with environmental factors and infectious diseases ecology. The extensive datasets on hematology, biochemistry, urinalysis, and microbiology results from this paper can be used as reference values for wild tapirs.

  12. Taxonomic identity determines N2 fixation by canopy trees across lowland tropical forests.

    PubMed

    Wurzburger, Nina; Hedin, Lars O

    2016-01-01

    Legumes capable of fixing atmospheric N2 are abundant and diverse in many tropical forests, but the factors determining ecological patterns in fixation are unresolved. A long-standing idea is that fixation depends on soil nutrients (N, P or Mo), but recent evidence shows that fixation may also differ among N2-fixing species. We sampled canopy-height trees across five species and one species group of N2-fixers along a landscape P gradient, and manipulated P and Mo to seedlings in a shadehouse. Our results identify taxonomy as the major determinant of fixation, with P (and possibly Mo) only influencing fixation following tree-fall disturbances. While 44% of trees did not fix N2, other trees fixed at high rates, with two species functioning as superfixers across the landscape. Our results raise the possibility that fixation is determined by biodiversity, evolutionary history and species-specific traits (tree growth rate, canopy stature and response to disturbance) in the tropical biome.

  13. Ground-Vegetation Clutter Affects Phyllostomid Bat Assemblage Structure in Lowland Amazonian Forest.

    PubMed

    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.

  14. The impact of rise of the Andes and Amazon landscape evolution on diversification of lowland terra-firme forest birds

    NASA Astrophysics Data System (ADS)

    Aleixo, A.; Wilkinson, M. J.

    2011-12-01

    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

  15. Aerosol Fluxes over Amazon Rain Forest Measured with the Eddy Covariance Method

    NASA Astrophysics Data System (ADS)

    Ahlm, L.; Nilsson, E. D.; Krejci, R.; Mårtensson, E. M.; Vogt, M.; Artaxo, P.

    2008-12-01

    We present measurements of vertical aerosol fluxes over the Amazon carried out on top of K34, a 50 meter high tower in the Cuieiras Reserve about 50 km north of Manaus in northern Brazil. The turbulent fluxes were measured with the eddy covariance method. The covariance of vertical wind speed from a sonic anemometer Gill Windmaster and total aerosol number concentration from a condensation particle counter (CPC) TSI 3010 provided the total number flux (diameter >0.01 μm). The covariance of vertical wind speed and size resolved number concentrations from an optical particle counter (OPC) Grimm 1.109 provided size resolved number fluxes in 15 bins from 0.25 μm to 2.5 μm diameter. Additionally fluxes of CO2 and H2O were derived from Li-7500 observations. The observational period, from early March to early August, includes both wet and dry season. OPC fluxes generally show net aerosol deposition both during wet and dry season with the largest downward fluxes during midday. CPC fluxes show different patterns in wet and dry season. During dry season, when number concentrations are higher, downward fluxes clearly dominate. In the wet season however, when number concentrations are lower, our data indicates that upward and downward fluxes are quite evenly distributed during course of a day. On average there is a peak in upward flux during late morning and another peak during the afternoon. Since the OPC fluxes in the same time show net deposition, there is an indication of net source of primary aerosol particles with diameters between 10 and 250 nm emitted from the rain forest. Future data analysis will hopefully shed light on origin and formation mechanism of these particles and thus provide a deeper insight in the rain forest - atmosphere interactions. The aerosol flux measurements were carried out as a part of the AMAZE project in collaboration with University of Sao Paulo, Brazil, and financial support was provided by Swedish International Development Cooperation

  16. Ground-Vegetation Clutter Affects Phyllostomid Bat Assemblage Structure in Lowland Amazonian Forest

    PubMed Central

    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. PMID:26066654

  17. A Method to Infer Interception Evaporation Using Eddy Covariance Measurements: Application Over an Eastern Amazon Old-growth Rain Forest

    NASA Astrophysics Data System (ADS)

    Czikowsky, M. J.; Fitzjarrald, D. R.; Sakai, R. K.; Moraes, O.; Acevedo, O.; Medeiros, L. E.

    2009-05-01

    We develop a general methodology to estimate rainfall interception using eddy covariance data that are available at a large number of worldwide flux tower sites. This method is then demonstrated using data from an old-growth rain forest site in the eastern Amazon. The approach is to estimate the 'excess' evaporation that occurs during and following individual precipitation events, using baseline evaporation time series obtained from long time series of flux data and creating ensemble averages from these precipitation events and base- state dry days. One advantage of this method over the traditional techniques of estimating interception using rain gauges alone is that the interception evaporation is directly measured and not determined as the residual of incident precipitation and throughfall. This method would also be useful in cases where rain gauge measures of precipitation are suspect, such as in fog or wind-driven conditions. Furthermore, the large differences in interception that can occur on a site due to varying forest canopy density, structure and the appearance of canopy gaps is smoothed out using the eddy covariance method as the size of the flux footprint area incorporates these variations, and provides an average interception value over the flux footprint area. Identification of light rainfall events not detected by an on-site tipping bucket rain gauge was aided by the use of a ceilometer. Results from an eastern Amazon old-growth rain forest site (the km67 site in LBA-ECO) show that for daytime events, interception percentages decrease with rainfall intensity, with mean interception for light (0-2 mm/hr), moderate (2-16 mm/hr), and heavy (greater than 16 mm/hr) rainfall-rate events being 18.0, 9.9, and 7.8 percent of incoming precipitation respectively. The mean interception for all events in the study (daytime and nighttime) was 11.6 %. Energy balance comparisons between dry and afternoon rain-days show an approximately 15 % increase of evaporative

  18. Phylogenetic Analysis of Local-Scale Tree Soil Associations in a Lowland Moist Tropical Forest

    PubMed Central

    Schreeg, Laura A.; Kress, W. John; Erickson, David L.; Swenson, Nathan G.

    2010-01-01

    Background Local plant-soil associations are commonly studied at the species-level, while associations at the level of nodes within a phylogeny have been less well explored. Understanding associations within a phylogenetic context, however, can improve our ability to make predictions across systems and can advance our understanding of the role of evolutionary history in structuring communities. Methodology/Principal Findings Here we quantified evolutionary signal in plant-soil associations using a DNA sequence-based community phylogeny and several soil variables (e.g., extractable phosphorus, aluminum and manganese, pH, and slope as a proxy for soil water). We used published plant distributional data from the 50-ha plot on Barro Colorado Island (BCI), Republic of Panamá. Our results suggest some groups of closely related species do share similar soil associations. Most notably, the node shared by Myrtaceae and Vochysiaceae was associated with high levels of aluminum, a potentially toxic element. The node shared by Apocynaceae was associated with high extractable phosphorus, a nutrient that could be limiting on a taxon specific level. The node shared by the large group of Laurales and Magnoliales was associated with both low extractable phosphorus and with steeper slope. Despite significant node-specific associations, this study detected little to no phylogeny-wide signal. We consider the majority of the ‘traits’ (i.e., soil variables) evaluated to fall within the category of ecological traits. We suggest that, given this category of traits, phylogeny-wide signal might not be expected while node-specific signals can still indicate phylogenetic structure with respect to the variable of interest. Conclusions Within the BCI forest dynamics plot, distributions of some plant taxa are associated with local-scale differences in soil variables when evaluated at individual nodes within the phylogenetic tree, but they are not detectable by phylogeny-wide signal. Trends

  19. Soil carbon dioxide and methane fluxes from lowland forests converted to oil palm and rubber plantations in Sumatra, Indonesia

    NASA Astrophysics Data System (ADS)

    Preuss, Evelyn; Corre, Marife D.; Damris, Muhammad; Tjoa, Aiyen; Rahayu Utami, Sri; Veldkamp, Edzo

    2015-04-01

    Demand for palm oil has increased strongly in recent decades. Global palm oil production quadrupled between 1990 and 2009, and although almost half of the global supply is already produced in Indonesia, a doubling of current production is planned for the next ten years. This agricultural expansion is achieved by conversion of rainforest. Land-use conversion affects soil carbon dioxide (CO2) and methane (CH4) fluxes through changes in nutrient availability and soil properties which, in turn, influence plant productivity, microbial activity and gas diffusivity. Our study was aimed to assess changes in soil CO2 and CH4 fluxes with forest conversion to oil palm and rubber plantations. Our study area was Jambi Province, Sumatra, Indonesia. We selected two soil landscapes in this region: loam and clay Acrisol soils. At each landscape, we investigated four land-use systems: lowland secondary rainforest, secondary forest with regenerating rubber (referred here as jungle rubber), rubber (7-17 years old) and oil palm plantations (9-16 years old). Each land use in each soil landscape was represented by four sites as replicates, totaling to 32 sites. We measured soil-atmosphere CH4 and CO2 fluxes using vented static chamber method with monthly sampling from November 2012 to December 2013. There were no differences in soil CO2 and CH4 fluxes (all P > 0.05) between soil landscapes for each land-use type. For soil CO2 fluxes, in both clay and loam Acrisol soil landscapes oil palm were lower compared to the other land uses (P < 0.007). In the clay Acrisol, soil CO2 fluxes were 107.2 ± 7.2 mg C m-2 h-1 for oil palm, and 195.9 ± 13.5 mg C m-2 h-1for forest, 185.3 ± 9.4 mg C m-2 h-1for jungle rubber and 182.8 ± 16.2 mg C m2 h-1for rubber. In the loam Acrisol, soil CO2 fluxes were 115.7 ± 11.0 mg CO2-C m2 h-1 for oil palm, and 186.6 ± 13.7, 178.7 ± 11.2, 182.9 ± 14.5 mg CO2-C m-2 h-1 for forest, jungle rubber and rubber, respectively. The seasonal patterns of soil CO2 fluxes

  20. Coordinated changes in photosynthesis, water relations and leaf nutritional traits of canopy trees along a precipitation gradient in lowland tropical forest.

    PubMed

    Santiago, Louis S; Kitajima, Kaoru; Wright, S Joseph; Mulkey, Stephen S

    2004-05-01

    We investigated leaf physiological traits of dominant canopy trees in four lowland Panamanian forests with contrasting mean annual precipitation (1,800, 2,300, 3,100 and 3,500 mm). There was near complete turn-over of dominant canopy tree species among sites, resulting in greater dominance of evergreen species with long-lived leaves as precipitation increased. Mean structural and physiological traits changed along this gradient as predicted by cost-benefit theories of leaf life span. Nitrogen content per unit mass (Nmass) and light- and CO2-saturated photosynthetic rates per unit mass (Pmass) of upper canopy leaves decreased with annual precipitation, and these changes were partially explained by increasing leaf thickness and decreasing specific leaf area (SLA). Comparison of 1,800 mm and 3,100 mm sites, where canopy access was available through the use of construction cranes, revealed an association among extended leaf longevity, greater structural defense, higher midday leaf water potential, and lower Pmass, Nmass, and SLA at wetter sites. Shorter leaf life spans and more enriched foliar delta15N values in drier sites suggest greater resorption and re-metabolism of leaf N in drier forest. Greater dominance of short-lived leaves with relatively high Pmass in drier sites reflects a strategy to maximize photosynthesis when water is available and to minimize water loss and respiration costs during rainless periods. Overall, our study links coordinated change in leaf functional traits that affect productivity and nutrient cycling to seasonality in lowland tropical forests.

  1. Dispersal of Culex quinquefasciatus (Diptera: Culicidae) in a Hawaiian rain forest.

    PubMed

    Lapointe, D A

    2008-07-01

    Introduced mosquito-borne pathogens avian malaria (Plasmodium relictum Grassi and Feletti) and avian pox virus (Avipoxvirus) have been implicated in the past extinctions and declines of Hawaiian avifauna and remain significant obstacles to the recovery and restoration of endemic Hawaiian birds. Effective management of avian disease will require extensive mosquito control efforts that are guided by the local ecology of the vector Culex quinquefasciatus Say (Diptera: Culicidae). During October and November 1997 and September through November 1998 five mark-release-recapture experiments with laboratory-reared Cx. quinquefasciatus were conducted in a native rain forest on Hawaii Island. Of the overall 66,047 fluorescent dye-marked and released females, 1,192 (1.8%) were recaptured in 43-52 CO2-baited traps operated for 10-12-d trapping periods. Recaptured mosquitoes were trapped in all directions and at distances up to 3 km from the release site. The cumulative mean distance traveled (MDTs) over the trapping period ranged from a high of 1.89 km after 11 d (September 1998) to a low of 0.81 km after 11 d (November 1998). Released mosquitoes moved predominately in a downwind direction and they seemed to use forestry roads as dispersal corridors. Applying an estimated MDT of 1.6 km to a geographical information system-generated map of the Hakalau Forest National Wildlife Refuge clearly demonstrated that the effective refuge area could be reduced 60% by mosquitoes infiltrating into managed refuge lands. These findings should have significant implications for the design of future refuges and development of effective mosquito-borne avian disease control strategies.

  2. Dispersal of Culex quinquefasciatus (Diptera: Culicidae) in a Hawaiian rain forest

    USGS Publications Warehouse

    Lapointe, D.A.

    2008-01-01

    Introduced mosquito-borne pathogens avian malaria (Plasmodium relictum Grassi and Feletti) and avian pox virus (Avipoxvirus) have been implicated in the past extinctions and declines of Hawaiian avifauna and remain significant obstacles to the recovery and restoration of endemic Hawaiian birds. Effective management of avian disease will require extensive mosquito control efforts that are guided by the local ecology of the vector Culex quinquefasciatus Say (Diptera: Culicidae). During October and November 1997 and September through November 1998 five mark-release-recapture experiments with laboratory-reared Cx. quinquefasciatus were conducted in a native rain forest on Hawaii Island. Of the overall 66,047 fluorescent dye-marked and released females, 1,192 (1.8%) were recaptured in 43-52 CO2-baited traps operated for 10-12-d trapping periods. Recaptured mosquitoes were trapped in all directions and at distances up to 3 km from the release site. The cumulative mean distance traveled (MDTs) over the trapping period ranged from a high of 1.89 km after 11 d (September 1998) to a low of 0.81 km after 11 d (November 1998). Released mosquitoes moved predominately in a downwind direction and they seemed to use forestry roads as dispersal corridors. Applying an estimated MDT of 1.6 km to a geographical information system-generated map of the Hakalau Forest National Wildlife Refuge clearly demonstrated that the effective refuge area could be reduced 60% by mosquitoes infiltrating into managed refuge lands. These findings should have significant implications for the design of future refuges and development of effective mosquito-borne avian disease control strategies.

  3. Carbon isotope fractionation by methane-oxidizing bacteria intropical rain forest soils

    SciTech Connect

    Teh, Yit Arn; Silver, Whendee L.; Conrad, Mark E.; Borglin,Sharon E.; Carlson, Charlotte M.

    2005-05-12

    Humid tropical forests have the potential to be significantsources or sinks of atmospheric methane (CH4), a radiatively importanttrace gas. Methane oxidation can consume a large fraction of the CH4produced in tropical soils, although controls on this process are poorlyunderstood. Using soil incubation experiments, we investigated theeffects of CH4 and oxygen (O2) concentrations on C isotope fractionationand CH4 oxidation in tropical rain forest soils. We also explored theeffects of these environmental variables on the isotope fractionationfactor for CH4 oxidation (alpha), which is widely used to evaluate therelative contributions of CH4 production and oxidation to the atmosphericCH4 pool. Methane oxidation was sensitive to CH4 at lower CH4concentrations (<850 ppmv) and insensitive to O2 concentrationsbetween 3 and 21 percent. Maximum rates of CH4 oxidation were between 8.2+- 1.2 and 11.3 +- 1.5 nmol CH4 hour-1 g dry soil-1. Measured values foralpha were sensitive to both CH4 oxidation rate and CH4 concentration.Alpha was inversely proportional to CH4 oxidation rate (r2 = 0.86, P<0.001) and positively correlated with CH4 concentration (r2 = 0.52, P<0.01). A multiple regression model that included CH4 oxidation rate,CH4 concentration, and the interaction of the two terms explained a highproportion of the variability in alpha (r2 = 0.94, P<0.0001). Thesedata suggest that it is possible to accurately determine alpha, allowingfor more precise estimates of CH4 oxidation by isotope massbalance.

  4. Experimental drought in a tropical rain forest increases soil carbon dioxide losses to the atmosphere.

    PubMed

    Cleveland, Cory C; Wieder, William R; Reed, Sasha C; Townsend, Alan R

    2010-08-01

    Climate models predict precipitation changes for much of the humid tropics, yet few studies have investigated the potential consequences of drought on soil carbon (C) cycling in this important biome. In wet tropical forests, drought could stimulate soil respiration via overall reductions in soil anoxia, but previous research suggests that litter decomposition is positively correlated with high rainfall fluxes that move large quantities of dissolved organic matter (DOM) from the litter layer to the soil surface. Thus, reduced rainfall could also limit C delivery to the soil surface, reducing respiration rates. We conducted a throughfall manipulation experiment to investigate how 25% and 50% reductions in rainfall altered both C movement into soils and the effects of those DOM fluxes on soil respiration rates. In response to the experimental drought, soil respiration rates increased in both the -25% and -50% treatments. Throughfall fluxes were reduced by 26% and 55% in the -25% and -50% treatments, respectively. However, total DOM fluxes leached from the litter did not vary between treatments, because the concentrations of leached DOM reaching the soil surface increased in response to the simulated drought. Annual DOM concentrations averaged 7.7 +/- 0.8, 11.2 +/- 0.9, and 15.8 +/- 1.2 mg C/L in the control, -25%, and -50% plots, respectively, and DOM concentrations were positively correlated with soil respiration rates. A laboratory incubation experiment confirmed the potential importance of DOM concentration on soil respiration rates, suggesting that this mechanism could contribute to the increase in CO2 fluxes observed in the reduced rainfall plots. Across all plots, the data suggested that soil CO2 fluxes were partially regulated by the magnitude and concentration of soluble C delivered to the soil, but also by soil moisture and soil oxygen availability. Together, our data suggest that declines in precipitation in tropical rain forests could drive higher CO2

  5. Survival and distribution of Vibrio cholerae in a tropical rain forest stream

    SciTech Connect

    Perez-Rosas, N.; Hazen, T.C.

    1988-12-31

    For 12 months Vibrio cholerae and fecal coliforms were monitored along with 9 other water quality parameters at 12 sites in a rain forest watershed in Puerto Rico. Densities of V. cholerae and fecal coliforms were not significantly correlated even though the highest densities of both bacteria were found at a sewage outfall. High densities of V. cholerae were also found at pristine sites high in the watershed. V. cholerae and Escherichia coli were inoculated into membrane diffusion chambers, placed at two sites and monitored for 5 days on two different occasions. Two different direct count methods indicated that the density of E. coli and V. cholerae did not change significantly during the course of either study. Physiological activity, as measured by INT-reduction and relative nucleic acid composition declined for E. coli during the first 12 h then increased and remained variable during the remainder of the study. V. cholerae activity, as measured by relative nucleic acid concentrations, remained high and unchanged for the entire study. INT-reduction in V. cholerae declined initially but regained nearly all of it`s original activity within 48 h. This study suggests that V. cholerae is an indigenous organism in tropical freshwaters and that assays other than fecal coliforms or E. coli must be used for assessing public health risk in tropical waters.

  6. A survey of pig production systems in the rain forest of the Pacific coast Colombia.

    PubMed

    Ocampo, L M; Leterme, P; Buldgen, A

    2005-05-01

    A questionnaire-based survey was conducted in small-scale pig farms in the rain forest of the Colombian Pacific coast in order to study aspects of reproduction, nutrition and productivity. A total of 124 farmers was interviewed. They owned, on average, 13.6 pigs, including 2.3 sows, mainly of the Zungo breed. Pigs are reared in extensive systems and are allowed to wander freely in search of food. The sows produce, on average, 9.6 piglets/litter but, owing to poor sanitary conditions, 1.5 are born dead and only 6.3 are weaned alive. Two-thirds of the sows have five litters or more and the boars are also kept for a long time. This leads to high consanguinity rates within the herd and low productivity. Diets are based on maize, banana, tubers (taro, cassava) and fruits (peach palm, among others), and are rich in energy but poor in protein and minerals. The lack of protein and mineral sources appears to be the main limiting factor of these extensive production systems. Tree forages could partially solve the problem but are used by only 2% of the farmers. It is concluded that decreasing inbreeding, better piglet management and provision of balanced diets are areas that require immediate improvement. PMID:15934639

  7. Structure and dynamics of mixed-species flocks in a Hawaiian rain forest

    USGS Publications Warehouse

    Hart, P.J.; Freed, L.A.

    2003-01-01

    Mixed-species flocks of native and introduced birds were studied for four years in an upper elevation Hawaiian rain forest. Those flocks were characterized by strong seasonality, large size, low species richness, high intraspecific abundance, a lack of migrants, and a general lack of territoriality or any sort of dominance hierarchy. There was high variability among years in patterns of occurrence at the species level, and high variability within years at the individual level. These flocks are loosely structured social groupings with apparently open membership. The fluid, unstable movement patterns, high degree of variability in size and composition, and lack of positive interspecific associations are not consistent with the "foraging enhancement" hypothesis for flocking. Two resident, endangered insectivores, the Akepa (Loxops coccineus) and Hawaii Creeper (Oreomystis mana) served as "nuclear" species. Flock composition was compared between two study sites that differed significantly in density of these two nuclear species. Flock size was similar at the two sites, primarily because the nuclear species were over-represented relative to their density. This observation suggests that birds are attempting to achieve a more optimal flock size at the lower density site.

  8. The neurotropic black yeast Exophiala dermatitidis has a possible origin in the tropical rain forest

    PubMed Central

    Sudhadham, M.; Prakitsin, S.; Sivichai, S.; Chaiyarat, R.; Dorrestein, G. M.; Menken, S.B.J.; de Hoog, G.S.

    2008-01-01

    The black yeast Exophiala dermatitidis is known as a rare etiologic agent of neurotropic infections in humans, occurring particularly in East and Southeast Asia. In search of its natural habitat, a large sampling was undertaken in temperate as well as in tropical climates. Sampling sites were selected on the basis of the origins of previously isolated strains, and on the basis of physiological properties of the species, which also determined a selective isolation protocol. The species was absent from outdoor environments in the temperate climate, but present at low abundance in comparable habitats in the tropics. Positive outdoor sites particularly included faeces of frugivorous birds and bats, in urban as well as in natural areas. Tropical fruits were found E. dermatitidis positive at low incidence. Of the human-made environments sampled, railway ties contaminated by human faeces and oily debris in the tropics were massively positive, while the known abundance of the fungus in steam baths was confirmed. On the basis of the species' oligotrophy, thermotolerance, acidotolerance, moderate osmotolerance, melanization and capsular yeast cells a natural life cycle in association with frugivorous animals in foci in the tropical rain forest, involving passage of living cells through the intestinal tract was hypothesized. The human-dominated environment may have become contaminated by ingestion of wild berries carrying fungal propagules PMID:19287537

  9. Global transcriptome response to ionic liquid by a tropical rain forest soil bacterium, Enterobacter lignolyticus.

    PubMed

    Khudyakov, Jane I; D'haeseleer, Patrik; Borglin, Sharon E; Deangelis, Kristen M; Woo, Hannah; Lindquist, Erika A; Hazen, Terry C; Simmons, Blake A; Thelen, Michael P

    2012-08-01

    To process plant-based renewable biofuels, pretreatment of plant feedstock with ionic liquids has significant advantages over current methods for deconstruction of lignocellulosic feedstocks. However, ionic liquids are often toxic to the microorganisms used subsequently for biomass saccharification and fermentation. We previously isolated Enterobacter lignolyticus strain SCF1, a lignocellulolytic bacterium from tropical rain forest soil, and report here that it can grow in the presence of 0.5 M 1-ethyl-3-methylimidazolium chloride, a commonly used ionic liquid. We investigated molecular mechanisms of SCF1 ionic liquid tolerance using a combination of phenotypic growth assays, phospholipid fatty acid analysis, and RNA sequencing technologies. Potential modes of resistance to 1-ethyl-3-methylimidazolium chloride include an increase in cyclopropane fatty acids in the cell membrane, scavenging of compatible solutes, up-regulation of osmoprotectant transporters and drug efflux pumps, and down-regulation of membrane porins. These findings represent an important first step in understanding mechanisms of ionic liquid resistance in bacteria and provide a basis for engineering microbial tolerance.

  10. A survey of pig production systems in the rain forest of the Pacific coast Colombia.

    PubMed

    Ocampo, L M; Leterme, P; Buldgen, A

    2005-05-01

    A questionnaire-based survey was conducted in small-scale pig farms in the rain forest of the Colombian Pacific coast in order to study aspects of reproduction, nutrition and productivity. A total of 124 farmers was interviewed. They owned, on average, 13.6 pigs, including 2.3 sows, mainly of the Zungo breed. Pigs are reared in extensive systems and are allowed to wander freely in search of food. The sows produce, on average, 9.6 piglets/litter but, owing to poor sanitary conditions, 1.5 are born dead and only 6.3 are weaned alive. Two-thirds of the sows have five litters or more and the boars are also kept for a long time. This leads to high consanguinity rates within the herd and low productivity. Diets are based on maize, banana, tubers (taro, cassava) and fruits (peach palm, among others), and are rich in energy but poor in protein and minerals. The lack of protein and mineral sources appears to be the main limiting factor of these extensive production systems. Tree forages could partially solve the problem but are used by only 2% of the farmers. It is concluded that decreasing inbreeding, better piglet management and provision of balanced diets are areas that require immediate improvement.

  11. Genetic structure and conservation of Mountain Lions in the South-Brazilian Atlantic Rain Forest.

    PubMed

    Castilho, Camila S; Marins-Sá, Luiz G; Benedet, Rodrigo C; Freitas, Thales R O

    2012-01-01

    The Brazilian Atlantic Rain Forest, one of the most endangered ecosystems worldwide, is also among the most important hotspots as regards biodiversity. Through intensive logging, the initial area has been reduced to around 12% of its original size. In this study we investigated the genetic variability and structure of the mountain lion, Puma concolor. Using 18 microsatellite loci we analyzed evidence of allele dropout, null alleles and stuttering, calculated the number of allele/locus, PIC, observed and expected heterozygosity, linkage disequilibrium, Hardy-Weinberg equilibrium, F(IS), effective population size and genetic structure (MICROCHECKER, CERVUS, GENEPOP, FSTAT, ARLEQUIN, ONESAMP, LDNe, PCAGEN, GENECLASS software), we also determine whether there was evidence of a bottleneck (HYBRIDLAB, BOTTLENECK software) that might influence the future viability of the population in south Brazil. 106 alleles were identified, with the number of alleles/locus ranging from 2 to 11. Mean observed heterozygosity, mean number of alleles and polymorphism information content were 0.609, 5.89, and 0.6255, respectively. This population presented evidence of a recent bottleneck and loss of genetic variation. Persistent regional poaching constitutes an increasing in the extinction risk. PMID:22481876

  12. The neurotropic black yeast Exophiala dermatitidis has a possible origin in the tropical rain forest.

    PubMed

    Sudhadham, M; Prakitsin, S; Sivichai, S; Chaiyarat, R; Dorrestein, G M; Menken, S B J; de Hoog, G S

    2008-01-01

    The black yeast Exophiala dermatitidis is known as a rare etiologic agent of neurotropic infections in humans, occurring particularly in East and Southeast Asia. In search of its natural habitat, a large sampling was undertaken in temperate as well as in tropical climates. Sampling sites were selected on the basis of the origins of previously isolated strains, and on the basis of physiological properties of the species, which also determined a selective isolation protocol. The species was absent from outdoor environments in the temperate climate, but present at low abundance in comparable habitats in the tropics. Positive outdoor sites particularly included faeces of frugivorous birds and bats, in urban as well as in natural areas. Tropical fruits were found E. dermatitidis positive at low incidence. Of the human-made environments sampled, railway ties contaminated by human faeces and oily debris in the tropics were massively positive, while the known abundance of the fungus in steam baths was confirmed. On the basis of the species' oligotrophy, thermotolerance, acidotolerance, moderate osmotolerance, melanization and capsular yeast cells a natural life cycle in association with frugivorous animals in foci in the tropical rain forest, involving passage of living cells through the intestinal tract was hypothesized. The human-dominated environment may have become contaminated by ingestion of wild berries carrying fungal propagules.

  13. Characteristics and formation of rain forest soils derived from late Quaternary basaltic rocks in Leyte, Philippines

    NASA Astrophysics Data System (ADS)

    Navarrete, Ian A.; Tsutsuki, Kiyoshi; Asio, Victor B.; Kondo, Renzo

    2009-09-01

    This study was conducted to evaluate the physical, chemical, and mineralogical characteristics of rain forest soils derived from late Quaternary basaltic rocks in Leyte, Philippines. Four sites along a catena were selected at an elevation of 75-112 m above sea level with an average annual rainfall of 3,000 mm and an average temperature of 28°C. Results indicate that the soils are deep, clayey, and reddish in color, which is indicative of the advanced stage of soil development. They also posses excellent physical condition (friable and highly porous) although they are plastic and sticky when wet as is usual for clayey soils. In terms of chemical characteristics, the soils are acidic with low CEC values and generally low in organic matter and nutrient contents. The clay mineralogy of the soils is dominated by halloysite and kaolinite with minor amounts of goethite and hematite, and they also have generally high dithionite-extractable Fe contents confirming the advanced stage of their development. The soils in the more stable slope positions (PL-1, PL-2, and PL-4) have generally similar characteristics and appeared more developed than the one in the less stable position (PL-3). The most important pedogenic processes that formed the soils appear to be weathering, loss of bases and acidification, desilification, ferrugination, clay formation and translocation, and structure formation. The nature of the parent rock and climatic conditions prevailing in the area as well as slope position appear to have dominant effects on the development of the soils.

  14. Global transcriptome response to ionic liquid by a tropical rain forest soil bacterium, Enterobacter lignolyticus.

    PubMed

    Khudyakov, Jane I; D'haeseleer, Patrik; Borglin, Sharon E; Deangelis, Kristen M; Woo, Hannah; Lindquist, Erika A; Hazen, Terry C; Simmons, Blake A; Thelen, Michael P

    2012-08-01

    To process plant-based renewable biofuels, pretreatment of plant feedstock with ionic liquids has significant advantages over current methods for deconstruction of lignocellulosic feedstocks. However, ionic liquids are often toxic to the microorganisms used subsequently for biomass saccharification and fermentation. We previously isolated Enterobacter lignolyticus strain SCF1, a lignocellulolytic bacterium from tropical rain forest soil, and report here that it can grow in the presence of 0.5 M 1-ethyl-3-methylimidazolium chloride, a commonly used ionic liquid. We investigated molecular mechanisms of SCF1 ionic liquid tolerance using a combination of phenotypic growth assays, phospholipid fatty acid analysis, and RNA sequencing technologies. Potential modes of resistance to 1-ethyl-3-methylimidazolium chloride include an increase in cyclopropane fatty acids in the cell membrane, scavenging of compatible solutes, up-regulation of osmoprotectant transporters and drug efflux pumps, and down-regulation of membrane porins. These findings represent an important first step in understanding mechanisms of ionic liquid resistance in bacteria and provide a basis for engineering microbial tolerance. PMID:22586090

  15. Measurement of heat and moisture fluxes at the top of the rain forest during ABLE

    NASA Technical Reports Server (NTRS)

    Fitzjarrald, David R.

    1987-01-01

    Observations are presented of turbulent heat, moisture, and momentum transport made at two levels, approximately 5 and 10 m above the Amazon rain forest canopy. Data acquired at 10 Hz included variances and some mixed third moments of vertical velocity, temperature, and humidity. Two features of the data appear to question the displacement height hypothesis: (1) The characteristic dissipation length scale in the near-canopy layer varied between 20 m in stable conditions to approximately 150 m during afternoon convective conditions, generally larger scales than would be expected; and (2) No appreciable difference in dissipation scales was seen at the two observed levels. Observed peaks in vertical velocity-temperature cospectra lead to similar length scale estimates for dominant eddies. Heat budgets on selected days show that frequent periods with negative heat flux concurrent with continuing positive moisture flux occur in early afternoon, and this is believed to indicate the patchy nature of canopy-atmosphere coupling. Vertical velocity skewness was observed to be negative on three successive days and exhibited a sharp positive gradient.

  16. Snaring to control feral pigs sus scrofa in a remote Hawaiian rain forest

    USGS Publications Warehouse

    Anderson, Stephen J.; Stone, Charles P.

    1993-01-01

    Feral pig Sus scrofa control in Kipahulu Valley, a remote rain forest in Haleakala National Park, Maui, Hawaiian Islands, has been achieved with snares over a 45-month period. Initial pig densities in fenced management units of 6·2 km2 and 7·8 km2were estimated at 6 animals/km2 and 14·3 animals/km2 for the two units, based on population reconstruction from animals killed and aged. During the 45 months of the study, 1978 snares were set, and 1·6 million snare nights were logged. Snare density reached 96/km2 and 200/km2 for the two management units by the end of the study. A mean effort of 43 worker hours/pig was used to remove 53 pigs from the upper management unit, and a mean of 7 worker hours/pig to remove 175 animals from the more densely populated lower unit. Pig activity monitoring along transects provided a good measure of control effectiveness until densities of about 1 pig/km2 were achieved, after which transects became less useful than scouting for determining pig activity.

  17. Genetic structure and conservation of Mountain Lions in the South-Brazilian Atlantic Rain Forest

    PubMed Central

    Castilho, Camila S.; Marins-Sá, Luiz G.; Benedet, Rodrigo C.; Freitas, Thales R.O.

    2012-01-01

    The Brazilian Atlantic Rain Forest, one of the most endangered ecosystems worldwide, is also among the most important hotspots as regards biodiversity. Through intensive logging, the initial area has been reduced to around 12% of its original size. In this study we investigated the genetic variability and structure of the mountain lion, Puma concolor. Using 18 microsatellite loci we analyzed evidence of allele dropout, null alleles and stuttering, calculated the number of allele/locus, PIC, observed and expected heterozygosity, linkage disequilibrium, Hardy-Weinberg equilibrium, FIS, effective population size and genetic structure (MICROCHECKER, CERVUS, GENEPOP, FSTAT, ARLEQUIN, ONESAMP, LDNe, PCAGEN, GENECLASS software), we also determine whether there was evidence of a bottleneck (HYBRIDLAB, BOTTLENECK software) that might influence the future viability of the population in south Brazil. 106 alleles were identified, with the number of alleles/locus ranging from 2 to 11. Mean observed heterozygosity, mean number of alleles and polymorphism information content were 0.609, 5.89, and 0.6255, respectively. This population presented evidence of a recent bottleneck and loss of genetic variation. Persistent regional poaching constitutes an increasing in the extinction risk. PMID:22481876

  18. Genetic structure and conservation of Mountain Lions in the South-Brazilian Atlantic Rain Forest.

    PubMed

    Castilho, Camila S; Marins-Sá, Luiz G; Benedet, Rodrigo C; Freitas, Thales R O

    2012-01-01

    The Brazilian Atlantic Rain Forest, one of the most endangered ecosystems worldwide, is also among the most important hotspots as regards biodiversity. Through intensive logging, the initial area has been reduced to around 12% of its original size. In this study we investigated the genetic variability and structure of the mountain lion, Puma concolor. Using 18 microsatellite loci we analyzed evidence of allele dropout, null alleles and stuttering, calculated the number of allele/locus, PIC, observed and expected heterozygosity, linkage disequilibrium, Hardy-Weinberg equilibrium, F(IS), effective population size and genetic structure (MICROCHECKER, CERVUS, GENEPOP, FSTAT, ARLEQUIN, ONESAMP, LDNe, PCAGEN, GENECLASS software), we also determine whether there was evidence of a bottleneck (HYBRIDLAB, BOTTLENECK software) that might influence the future viability of the population in south Brazil. 106 alleles were identified, with the number of alleles/locus ranging from 2 to 11. Mean observed heterozygosity, mean number of alleles and polymorphism information content were 0.609, 5.89, and 0.6255, respectively. This population presented evidence of a recent bottleneck and loss of genetic variation. Persistent regional poaching constitutes an increasing in the extinction risk.

  19. Nutrient cycling in a tropical seasonal rain forest of Xishuangbanna, Southwest China. Part 1: tree species: nutrient distribution and uptake.

    PubMed

    Shanmughavel, P; Sha, L; Zheng, Z; Cao, M

    2001-12-01

    Tropical rain forests are characterized by large numbers of the species with diverse growth habits. The objective of the present study was to determine the distribution of nutrient content in the major trees of the tropical rain forests in Xishuangbanna. This will improve the understanding of the nutrient losses from such sites that result from harvesting and flow of nutrients within the ecosystem and lead to the development of effective and rational forest management strategies. Based on the results in this study, the distribution of nutrients among biomass components of trees varied: The ordering of major elements concentrations was K > N > Mg > Ca > P in branch, stem and root tissues but was N > K > Mg > Ca > P in leaves. The maximum amount of all nutrients per ha occurred in the stems followed by branches, roots and leaves. Of the total uptake of 6167.7 kg ha(-1) of all nutrients, the contribution of various nutrients was found to be N (2010.6 t ha(-1)), P (196.3 t ha(-1)), K (2123.8 kg ha(-1)), Ca (832 kg ha(-1)) and Mg (1005 kg ha(-1)). However, comparing the nutrient uptake of other tropical and sub tropical forests, the results indicated that rates for the Xishuangbanna forests were 20-35% lower than previously reported values.

  20. Nutrient limitation in three lowland tropical forests in southern China receiving high nitrogen deposition: insights from fine root responses to nutrient additions.

    PubMed

    Zhu, Feifei; Yoh, Muneoki; Gilliam, Frank S; Lu, Xiankai; Mo, Jiangming

    2013-01-01

    Elevated nitrogen (N) deposition to tropical forests may accelerate ecosystem phosphorus (P) limitation. This study examined responses of fine root biomass, nutrient concentrations, and acid phosphatase activity (APA) of bulk soil to five years of N and P additions in one old-growth and two younger lowland tropical forests in southern China. The old-growth forest had higher N capital than the two younger forests from long-term N accumulation. From February 2007 to July 2012, four experimental treatments were established at the following levels: Control, N-addition (150 kg N ha(-1) yr(-1)), P-addition (150 kg P ha(-1) yr(-1)) and N+P-addition (150 kg N ha(-1) yr(-1) plus 150 kg P ha(-1) yr(-1)). We hypothesized that fine root growth in the N-rich old-growth forest would be limited by P availability, and in the two younger forests would primarily respond to N additions due to large plant N demand. Results showed that five years of N addition significantly decreased live fine root biomass only in the old-growth forest (by 31%), but significantly elevated dead fine root biomass in all the three forests (by 64% to 101%), causing decreased live fine root proportion in the old-growth and the pine forests. P addition significantly increased live fine root biomass in all three forests (by 20% to 76%). The combined N and P treatment significantly increased live fine root biomass in the two younger forests but not in the old-growth forest. These results suggest that fine root growth in all three study forests appeared to be P-limited. This was further confirmed by current status of fine root N:P ratios, APA in bulk soil, and their responses to N and P treatments. Moreover, N addition significantly increased APA only in the old-growth forest, consistent with the conclusion that the old-growth forest was more P-limited than the younger forests.

  1. Habitat fragmentation and haemoparasites in the common fruit bat, Artibeus jamaicensis (Phyllostomidae) in a tropical lowland forest in Panamá.

    PubMed

    Cottontail, V M; Wellinghausen, N; Kalko, E K V

    2009-09-01

    Anthropogenic influence on ecosystems, such as habitat fragmentation, impacts species diversity and interactions. There is growing evidence that degradation of habitats favours disease and hence affects ecosystem health. The prevalence of haemoparasites in the Common Fruit Bat (Artibeus jamaicensis) in a tropical lowland forest in Panamá was studied. We assessed the relation of haemoparasite to the general condition of the animals and tested for possible association of haemoparasite prevalence to habitat fragmentation, with special focus on trypanosomes. Overall, a total of 250 A. jamaicensis sampled from fragmented sites, here man-made, forested islands in Lake Gatùn, and sites in the adjacent, continuous forest in and around the Barro Colorado Nature Monument were examined. Using microscopy and DNA-sequencing 2 dominant types of haemoparasite infections, trypanosomes and Litomosoides (Nematoda) were identified. Trypanosome prevalence was significantly higher in bats from forest fragments, than in bats captured in continuous forest. We attribute this to the loss of species richness in forest fragments and specific characteristics of the fragments favouring trypanosome transmission, in particular changes in vegetation cover. Interestingly, the effect of habitat fragmentation on the prevalence of trypanosomes as multi-host parasites could not be observed in Litomosoides which probably has a higher host specificity and might be affected less by overall diversity loss.

  2. Peat initiation, soil carbon accumulation, fire, and vegetation changes in north-central Canadian arctic lowland forest peatlands during the Holocene

    NASA Astrophysics Data System (ADS)

    Camill, P.; Umbanhowar, C. E., Jr.; Edlund, M. B.; Geiss, C. E.

    2015-12-01

    Peat-forming regions are significant components of the earth system in terms of carbon exchange between the atmosphere and biosphere. While attention has been given to processes controlling carbon accumulation in major peatland/lowland regions at high latitudes, less is known about the processes controlling soil carbon accumulation rates in other globally abundant peat-forming ecosystems, such as lowland arctic forests. These systems are potentially important for two reasons: (1) Many lowland forest peatlands exist at the interface between uplands and aquatic systems; the onset and rate of peat accumulation, as well as the composition of peat mosses, may therefore alter the biogeochemical properties of lakes and streams; (2) soil carbon accumulation might differ from rates observed from the larger open peatlands, offering additional insights to the vulnerability of high-latitude peat to climatic change. We collected and dated 25 peat cores from eight lake sites in an 18,000-km2 low-arctic region of Manitoba Canada and measured areal carbon accumulation rates, charcoal concentration (as a proxy for fire severity), and plant macrofossils (as a proxy for vegetation change). The distribution of basal radiocarbon dates indicates that the oldest peat initiation occurred 7,000-8,000 B.P. in post-glacial landscapes, but peak peat formation occurred < 3,000 B.P., presumably as landscape paludification rose with increased net moisture during Neoglacial cooling. In locations where peat initiation occurred before 6,000 B.P., the initial communities were variable (bog-poor fen-moderate rich fen), whereas most sites initiating after 6,000 B.P. formed (and remained) as bogs, suggesting increasing dominance of Sphagnum peatmosses as paludification progressed. Carbon accumulation rates were consistently low (10-30 gm-2y-1), with no clear correlation to fire. Also absent was rapid accumulation early in the peatland development characteristic of early successional fens. These results

  3. Modelling the Distribution of Forest-Dependent Species in Human-Dominated Landscapes: Patterns for the Pine Marten in Intensively Cultivated Lowlands

    PubMed Central

    Balestrieri, Alessandro; Bogliani, Giuseppe; Boano, Giovanni; Ruiz-González, Aritz; Saino, Nicola; Costa, Stefano; Milanesi, Pietro

    2016-01-01

    In recent years, the “forest-specialist” pine marten Martes martes has been reported to also occur also in largely fragmented, lowland landscapes of north-western Italy. The colonization of such an apparently unsuitable area provided the opportunity for investigating pine marten ecological requirements and predicting its potential south- and eastwards expansion. We collected available pine marten occurrence data in the flood plain of the River Po (N Italy) and relate them to 11 environmental variables by developing nine Species Distribution Models. To account for inter-model variability we used average ensemble predictions (EP). EP predicted a total of 482 suitable patches (8.31% of the total study area) for the pine marten. The main factors driving pine marten occurrence in the western River Po plain were the distance from watercourses and the distance from woods. EP suggested that the pine marten may further expand in the western lowland, whilst the negligible residual wood cover of large areas in the central and eastern plain makes the habitat unsuitable for the pine marten, except for some riparian corridors and the pine wood patches bordering the Adriatic coast. Based on our results, conservation strategies should seek to preserve remnant forest patches and enhance the functional connectivity provided by riparian corridors. PMID:27368056

  4. Modelling the Distribution of Forest-Dependent Species in Human-Dominated Landscapes: Patterns for the Pine Marten in Intensively Cultivated Lowlands.

    PubMed

    Balestrieri, Alessandro; Bogliani, Giuseppe; Boano, Giovanni; Ruiz-González, Aritz; Saino, Nicola; Costa, Stefano; Milanesi, Pietro

    2016-01-01

    In recent years, the "forest-specialist" pine marten Martes martes has been reported to also occur also in largely fragmented, lowland landscapes of north-western Italy. The colonization of such an apparently unsuitable area provided the opportunity for investigating pine marten ecological requirements and predicting its potential south- and eastwards expansion. We collected available pine marten occurrence data in the flood plain of the River Po (N Italy) and relate them to 11 environmental variables by developing nine Species Distribution Models. To account for inter-model variability we used average ensemble predictions (EP). EP predicted a total of 482 suitable patches (8.31% of the total study area) for the pine marten. The main factors driving pine marten occurrence in the western River Po plain were the distance from watercourses and the distance from woods. EP suggested that the pine marten may further expand in the western lowland, whilst the negligible residual wood cover of large areas in the central and eastern plain makes the habitat unsuitable for the pine marten, except for some riparian corridors and the pine wood patches bordering the Adriatic coast. Based on our results, conservation strategies should seek to preserve remnant forest patches and enhance the functional connectivity provided by riparian corridors.

  5. Nutrient allocation among plant organs across 13 tree species in three Bornean rain forests with contrasting nutrient availabilities.

    PubMed

    Aoyagi, Ryota; Kitayama, Kanehiro

    2016-07-01

    Allocation of nitrogen (N) and phosphorus (P) among plant organs is an important factor regulating growth rate, which is a key ecological process associated with plant life-history strategies. However, few studies have explored how N and P investment in photosynthetic (leaves) and non-photosynthetic (stems and roots) organs changes in relation to depletion of each element. We investigated nutrient concentrations of plant organs in relation to whole-plant nutrient concentration (total nutrient weight per total biomass) as an index of nutrient status of each individual using the saplings of the 13 species in three tropical rain forests with contrasting N and P availabilities (tropical evergreen forests and tropical heath forests). We found a steeper decrease in foliar N concentration than foliar P concentration with decreasing whole-plant nutrient concentration. Moreover, the steeper decrease in foliar N concentration was associated with relatively stable N concentration in stems, and vice versa for P. We suggest that the depletion of N is associated with a rapid dilution of foliar N because the cell walls in non-photosynthetic organs function as an N sink. On the other hand, these species can maintain foliar P concentration by decreasing stem P concentrations despites the depletion of P. Our results emphasize the significance of non-photosynthetic organs as an N sink for understanding the variation of foliar nutrient concentrations for the tree species in the three Bornean rain forests with different N and P availabilities.

  6. Spatial distribution and interspecific associations of tree species in a tropical seasonal rain forest of China.

    PubMed

    Lan, Guoyu; Getzin, Stephan; Wiegand, Thorsten; Hu, Yuehua; Xie, Guishui; Zhu, Hua; Cao, Min

    2012-01-01

    Studying the spatial pattern and interspecific associations of plant species may provide valuable insights into processes and mechanisms that maintain species coexistence. Point pattern analysis was used to analyze the spatial distribution patterns of twenty dominant tree species, their interspecific spatial associations and changes across life stages in a 20-ha permanent plot of seasonal tropical rainforest in Xishuangbanna, China, to test mechanisms maintaining species coexistence. Torus-translation tests were used to quantify positive or negative associations of the species to topographic habitats. The results showed: (1) fourteen of the twenty tree species were negatively (or positively) associated with one or two of the topographic variables, which evidences that the niche contributes to the spatial pattern of these species. (2) Most saplings of the study species showed a significantly clumped distribution at small scales (0-10 m) which was lost at larger scales (10-30 m). (3) The degree of spatial clumping deceases from saplings, to poles, to adults indicates that density-dependent mortality of the offspring is ubiquitous in species. (4) It is notable that a high number of positive small-scale interactions were found among the twenty species. For saplings, 42.6% of all combinations of species pairs showed positive associations at neighborhood scales up to five meters, but only 38.4% were negative. For poles and adults, positive associations at these distances still made up 45.5% and 29.5%, respectively. In conclusion, there is considerable evidence for the presence of positive interactions among the tree species, which suggests that species herd protection may occur in our plot. In addition, niche assembly and limited dispersal (likely) contribute to the spatial patterns of tree species in the tropical seasonal rain forest in Xishuangbanna, China. PMID:23029394

  7. Carbon delivery to deep mineral horizons in Hawaiian rain forest soils

    NASA Astrophysics Data System (ADS)

    Marin-Spiotta, Erika; Chadwick, Oliver A.; Kramer, Marc; Carbone, Mariah S.

    2011-09-01

    This study aimed to better understand the mechanisms for soil organic matter delivery to and accumulation in mineral horizons of tropical rain forest, volcanic soils. We used soil morphology, lysimetry, isotopes, and spectroscopy to investigate the role of preferential flow paths in the delivery of carbon (C) to the subsoil. High rainfall, high primary productivity, and the dominance of highly reactive, short-range-order minerals combine to sequester substantial stocks of soil C with long mean residence times. The soils have large peds, separated by wide cracks, which form a network of channels propagating downward through the top 40 to 60 cm, facilitating macropore flow. The channel infillings and crack surfaces were enriched in organic material (OM) with lower C:N ratios, and had higher ammonium oxalate-extractable Al, and lower ammonium oxalate-extractable Fe than the adjacent mineral bulk soil. CP MAS 13C-NMR spectra of OM accumulating at depth showed strong signal intensities in the carboxyl and carbonyl C regions, indicative of organic acids, while decaying roots showed greater contributions of aromatic and O-alkyl C. The ratios of alkyl-to-O-alkyl C in the organic infillings were more similar to those of the bulk Bh and to dissolved organic matter than to those of decaying roots. Radiocarbon-based ages of OM infillings at >50 cm depth were significantly younger than the mineral soil (2000 years versus 7000 years). Respired CO2 from incubated soils showed that OM accumulating at depth is a mixture of modern and much older C, providing further evidence for the downward movement of fresh C.

  8. Spatial distribution and interspecific associations of tree species in a tropical seasonal rain forest of China.

    PubMed

    Lan, Guoyu; Getzin, Stephan; Wiegand, Thorsten; Hu, Yuehua; Xie, Guishui; Zhu, Hua; Cao, Min

    2012-01-01

    Studying the spatial pattern and interspecific associations of plant species may provide valuable insights into processes and mechanisms that maintain species coexistence. Point pattern analysis was used to analyze the spatial distribution patterns of twenty dominant tree species, their interspecific spatial associations and changes across life stages in a 20-ha permanent plot of seasonal tropical rainforest in Xishuangbanna, China, to test mechanisms maintaining species coexistence. Torus-translation tests were used to quantify positive or negative associations of the species to topographic habitats. The results showed: (1) fourteen of the twenty tree species were negatively (or positively) associated with one or two of the topographic variables, which evidences that the niche contributes to the spatial pattern of these species. (2) Most saplings of the study species showed a significantly clumped distribution at small scales (0-10 m) which was lost at larger scales (10-30 m). (3) The degree of spatial clumping deceases from saplings, to poles, to adults indicates that density-dependent mortality of the offspring is ubiquitous in species. (4) It is notable that a high number of positive small-scale interactions were found among the twenty species. For saplings, 42.6% of all combinations of species pairs showed positive associations at neighborhood scales up to five meters, but only 38.4% were negative. For poles and adults, positive associations at these distances still made up 45.5% and 29.5%, respectively. In conclusion, there is considerable evidence for the presence of positive interactions among the tree species, which suggests that species herd protection may occur in our plot. In addition, niche assembly and limited dispersal (likely) contribute to the spatial patterns of tree species in the tropical seasonal rain forest in Xishuangbanna, China.

  9. Spatial Distribution and Interspecific Associations of Tree Species in a Tropical Seasonal Rain Forest of China

    PubMed Central

    Lan, Guoyu; Getzin, Stephan; Wiegand, Thorsten; Hu, Yuehua; Xie, Guishui; Zhu, Hua; Cao, Min

    2012-01-01

    Studying the spatial pattern and interspecific associations of plant species may provide valuable insights into processes and mechanisms that maintain species coexistence. Point pattern analysis was used to analyze the spatial distribution patterns of twenty dominant tree species, their interspecific spatial associations and changes across life stages in a 20-ha permanent plot of seasonal tropical rainforest in Xishuangbanna, China, to test mechanisms maintaining species coexistence. Torus-translation tests were used to quantify positive or negative associations of the species to topographic habitats. The results showed: (1) fourteen of the twenty tree species were negatively (or positively) associated with one or two of the topographic variables, which evidences that the niche contributes to the spatial pattern of these species. (2) Most saplings of the study species showed a significantly clumped distribution at small scales (0–10 m) which was lost at larger scales (10–30 m). (3) The degree of spatial clumping deceases from saplings, to poles, to adults indicates that density-dependent mortality of the offspring is ubiquitous in species. (4) It is notable that a high number of positive small-scale interactions were found among the twenty species. For saplings, 42.6% of all combinations of species pairs showed positive associations at neighborhood scales up to five meters, but only 38.4% were negative. For poles and adults, positive associations at these distances still made up 45.5% and 29.5%, respectively. In conclusion, there is considerable evidence for the presence of positive interactions among the tree species, which suggests that species herd protection may occur in our plot. In addition, niche assembly and limited dispersal (likely) contribute to the spatial patterns of tree species in the tropical seasonal rain forest in Xishuangbanna, China. PMID:23029394

  10. Coexistence and community structure of tropical trees in a Hawaiian montane rain forest

    USGS Publications Warehouse

    Hatfield, J.S.; Link, W.A.; Dawson, D.K.; Lindquist, E.L.

    1996-01-01

    We measured the diameter at breast height of all trees and shrubs > 5 meters in height, including standing dead trees, on 68 0.04-hectare study plots in a montane, subtropical rain forest on Mauna Loa, Hawai`i. The canopy species consisted of 88 percent Metrosideros polymorpha (ohia) and 12 percent Acacia koa (koa). Negative associations were found between the densities of koa and ohia, the density of koa and the total basal area of ohia, and the total basal areas of koa and ohia. The two-species lottery competition model, a stochastic model in which the coexistence of two species in a space-limited community results from temporal variation in recruitment and death rates, predicts a quadratic-beta distribution for the proportion of space occupied by each species. A discrete version of the quadratic-beta distribution, the quadratic-beta binomial distribution, was fit to the live koa and ohia densities and assessed with goodness-of-fit tests. Likelihood ratio tests provided evidence that the mean adult death rates of the two species were equal but that the relative competitive abilities of the two species favored ohia. These tests were corroborated by a contingency table analysis of death rates based on standing dead trees and growth rate studies which report that koa grows much faster than ohia. The lottery model predicts a positive covariance between death rates and ohia recruitment when mean death rates are equal and koa has a higher growth rate than ohia. We argue that the competitive advantage of ohia is due to its superior dispersal ability into large gaps, which would yield the positive covariance described above, and it is this positive covariance term that skews the occupation of space in favor of ohia.

  11. Experimental drought in a tropical rain forest increases soil carbon dioxide losses to the atmosphere

    USGS Publications Warehouse

    Cleveland, C.C.; Wieder, W.R.; Reed, S.C.; Townsend, A.R.

    2010-01-01

    Climate models predict precipitation changes for much of the humid tropics, yet few studies have investigated the potential consequences of drought on soil carbon (C) cycling in this important biome. In wet tropical forests, drought could stimulate soil respiration via overall reductions in soil anoxia, but previous research suggests that litter decomposition is positively correlated with high rainfall fluxes that move large quantities of dissolved organic matter (DOM) from the litter layer to the soil surface. Thus, reduced rainfall could also limit C delivery to the soil surface, reducing respiration rates. We conducted a throughfall manipulation experiment to investigate how 25% and 50% reductions in rainfall altered both C movement into soils and the effects of those DOM fluxes on soil respiration rates. In response to the experimental drought, soil respiration rates increased in both the -25% and -50% treatments. Throughfall fluxes were reduced by 26% and 55% in the-25% and-50% treatments, respectively. However, total DOM fluxes leached from the litter did not vary between treatments, because the concentrations of leached DOM reaching the soil surface increased in response to the simulated drought. Annual DOM concentrations averaged 7.7 ?? 0.8, 11.2 ?? 0.9, and 15.8 ?? 1.2 mg C/L in the control, -25%, and -50% plots, respectively, and DOM concentrations were positively correlated with soil respiration rates. A laboratory incubation experiment confirmed the potential importance of DOM concentration on soil respiration rates, suggesting that this mechanism could contribute to the increase in CO2 fluxes observed in the reduced rainfall plots. Across all plots, the data suggested that soil CO2 fluxes were partially regulated by the magnitude and concentration of soluble C delivered to the soil, but also by soil moisture and soil oxygen availability. Together, our data suggest that declines in precipitation in tropical rain forests could drive higher CO2 fluxes to

  12. Experimental drought in a tropical rain forest increases soil carbon dioxide losses to the atmosphere

    USGS Publications Warehouse

    Cleveland, Cory C.; Wieder, William R.; Reed, Sasha C.; Townsend, Alan R.

    2010-01-01

    Climate models predict precipitation changes for much of the humid tropics, yet few studies have investigated the potential consequences of drought on soil carbon (C) cycling in this important biome. In wet tropical forests, drought could stimulate soil respiration via overall reductions in soil anoxia, but previous research suggests that litter decomposition is positively correlated with high rainfall fluxes that move large quantities of dissolved organic matter (DOM) from the litter layer to the soil surface. Thus, reduced rainfall could also limit C delivery to the soil surface, reducing respiration rates. We conducted a throughfall manipulation experiment to investigate how 25% and 50% reductions in rainfall altered both C movement into soils and the effects of those DOM fluxes on soil respiration rates. In response to the experimental drought, soil respiration rates increased in both the -25% and -50% treatments. Throughfall fluxes were reduced by 26% and 55% in the -25% and -50% treatments, respectively. However, total DOM fluxes leached from the litter did not vary between treatments, because the concentrations of leached DOM reaching the soil surface increased in response to the simulated drought. Annual DOM concentrations averaged 7.7 ± 0.8, 11.2 ± 0.9, and 15.8 ± 1.2 mg C/L in the control, -25%, and -50% plots, respectively, and DOM concentrations were positively correlated with soil respiration rates. A laboratory incubation experiment confirmed the potential importance of DOM concentration on soil respiration rates, suggesting that this mechanism could contribute to the increase in CO2 fluxes observed in the reduced rainfall plots. Across all plots, the data suggested that soil CO2 fluxes were partially regulated by the magnitude and concentration of soluble C delivered to the soil, but also by soil moisture and soil oxygen availability. Together, our data suggest that declines in precipitation in tropical rain forests could drive higher CO2 fluxes

  13. Conversion of tropical lowland forest reduces nutrient return through litterfall, and alters nutrient use efficiency and seasonality of net primary production.

    PubMed

    Kotowska, Martyna M; Leuschner, Christoph; Triadiati, Triadiati; Hertel, Dietrich

    2016-02-01

    Tropical landscapes are not only rapidly transformed by ongoing land-use change, but are additionally confronted by increasing seasonal climate variation. There is an increasing demand for studies analyzing the effects and feedbacks on ecosystem functioning of large-scale conversions of tropical natural forest into intensively managed cash crop agriculture. We analyzed the seasonality of aboveground litterfall, fine root litter production, and aboveground woody biomass production (ANPP(woody)) in natural lowland forests, rubber agroforests under natural tree cover ("jungle rubber"), rubber and oil palm monocultures along a forest-to-agriculture transformation gradient in Sumatra. We hypothesized that the temporal fluctuation of litter production increases with increasing land-use intensity, while the associated nutrient fluxes and nutrient use efficiency (NUE) decrease. Indeed, the seasonal variation of aboveground litter production and ANPP(woody) increased from the natural forest to the plantations, while aboveground litterfall generally decreased. Nutrient return through aboveground litter was mostly highest in the natural forest; however, it was significantly lower only in rubber plantations. NUE of N, P and K was lowest in the oil palm plantations, with natural forest and the rubber systems showing comparably high values. Root litter production was generally lower than leaf litter production in all systems, while the root-to-leaf ratio of litter C flux increased along the land-use intensity gradient. Our results suggest that nutrient and C cycles are more directly affected by climate seasonality in species-poor agricultural systems than in species-rich forests, and therefore might be more susceptible to inter-annual climate fluctuation and climate change. PMID:26546083

  14. Conversion of tropical lowland forest reduces nutrient return through litterfall, and alters nutrient use efficiency and seasonality of net primary production.

    PubMed

    Kotowska, Martyna M; Leuschner, Christoph; Triadiati, Triadiati; Hertel, Dietrich

    2016-02-01

    Tropical landscapes are not only rapidly transformed by ongoing land-use change, but are additionally confronted by increasing seasonal climate variation. There is an increasing demand for studies analyzing the effects and feedbacks on ecosystem functioning of large-scale conversions of tropical natural forest into intensively managed cash crop agriculture. We analyzed the seasonality of aboveground litterfall, fine root litter production, and aboveground woody biomass production (ANPP(woody)) in natural lowland forests, rubber agroforests under natural tree cover ("jungle rubber"), rubber and oil palm monocultures along a forest-to-agriculture transformation gradient in Sumatra. We hypothesized that the temporal fluctuation of litter production increases with increasing land-use intensity, while the associated nutrient fluxes and nutrient use efficiency (NUE) decrease. Indeed, the seasonal variation of aboveground litter production and ANPP(woody) increased from the natural forest to the plantations, while aboveground litterfall generally decreased. Nutrient return through aboveground litter was mostly highest in the natural forest; however, it was significantly lower only in rubber plantations. NUE of N, P and K was lowest in the oil palm plantations, with natural forest and the rubber systems showing comparably high values. Root litter production was generally lower than leaf litter production in all systems, while the root-to-leaf ratio of litter C flux increased along the land-use intensity gradient. Our results suggest that nutrient and C cycles are more directly affected by climate seasonality in species-poor agricultural systems than in species-rich forests, and therefore might be more susceptible to inter-annual climate fluctuation and climate change.

  15. Effects of seasonality and girdling on the age of stem CO2 in mature tropical lowland forest trees (Scleronema micranthum)

    NASA Astrophysics Data System (ADS)

    Muhr, Jan; Kunert, Norbert; Angert, Alon; Higuchi, Niro; Trumbore, Susan E.

    2014-05-01

    Little is known about the use of carbon (C) that was assimilated more than 1 year previously in trees. As a tree's lifetime is measured in decades to centuries, and trees are known to be able to build up essential nonstructural C reserves, it is possible that years elapse between fixation and later metabolic return of C to the atmosphere. We will refer to this elapsed time here as the 'age' of CO2, and we measure it by comparing the radiocarbon (14C) signature of CO2 emitted by trees with the observed rate of decline in atmospheric 14C-CO2. Here, we report data from Scleronema micranthum trees from a tropical lowland forest near Manaus, Brazil. Starting with 7 trees in 2012, we looked for seasonal changes in the age of CO2 emitted from the tree stem surface into the surrounding atmosphere as well as CO2 extracted from several depths (4, 8, and 12 cm) within the tree stem. We found no clear seasonality, but instead found that almost all samples were influenced by CO2 originating from sources fixed up to several years previously, suggesting that trees make use of storage C pools on a regular basis. There was a clear pattern of CO2 samples getting older the deeper from the stem they were extracted. The oldest samples, extracted from 12 cm depth, were made up of C fixed up to 30 years previously in some cases. The CO2 that is emitted into the atmosphere at the stem surface presumably represents a mixture of CO2 produced at various depths within the stem, and hence on average was substantially younger than these old samples, but still had an average age between 0-6 years. These findings of trees regularly using previously fixed C contradict the widespread assumption that trees mainly rely on recent assimilates for respiration unless forced to mobilize C from older pools due to environmental conditions limiting assimilation rates. In April 2013, we increased the number of investigated trees from 7 to 12. Initially, we kept the original sampling design, measuring seasonal

  16. The Impact of Rise of the Andes and Amazon Landscape Evolution on Diversification of Lowland terra-firme Forest Birds

    NASA Technical Reports Server (NTRS)

    Aleixo, Alexandre; Wilkinson, M. Justin

    2011-01-01

    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

  17. Fine roots, arbuscular mycorrhizal hyphae and soil nutrients in four neotropical rain forests: patterns across large geographic distances.

    PubMed

    Powers, Jennifer S; Treseder, Kathleen K; Lerdau, Manuel T

    2005-03-01

    * It is commonly hypothesized that stand-level fine root biomass increases as soil fertility decreases both within and among tropical forests, but few data exist to test this prediction across broad geographic scales. This study investigated the relationships among fine roots, arbuscular mycorrhizal (AM) fungi and soil nutrients in four lowland, neotropical rainforests. * Within each forest, samples were collected from plots that differed in fertility and above-ground biomass, and fine roots, AM hyphae and total soil nutrients were measured. * Among sites, total fine root mass varied by a factor of three, from 237+/-19 g m-2 in Costa Rica to 800+/-116 g m-2 in Brazil (0-40 cm depth). Both root mass and length were negatively correlated to soil nitrogen and phosphorus, but AM hyphae were not related to nutrients, root properties or above-ground biomass. * These results suggest that understanding how soil fertility affects fine roots is an additional factor that may improve the representation of root functions in global biogeochemical models or biome-wide averages of root properties in tropical forests. PMID:15720702

  18. Retrieval of Vertical LAI Profiles Over Tropical Rain Forests using Waveform Lidar at La Selva, Costa Rica

    NASA Technical Reports Server (NTRS)

    Tang, Hao; Dubayah, Ralph; Swatantra, Anu; Hofton, Michelle; Sheldon, Sage; Clark, David B.; Blair, Bryan

    2012-01-01

    This study explores the potential of waveform lidar in mapping the vertical and spatial distributions of leaf area index (LAI) over the tropical rain forest of La Selva Biological Station in Costa Rica. Vertical profiles of LAI were derived at 0.3 m height intervals from the Laser Vegetation Imaging Sensor (LVIS) data using the Geometric Optical and Radiative Transfer (GORT) model. Cumulative LAI profiles obtained from LVIS were validated with data from 55 ground to canopy vertical transects using a modular field tower to destructively sample all vegetation. Our results showed moderate agreement between lidar and field derived LAI (r2=0.42, RMSE=1.91, bias=-0.32), which further improved when differences between lidar and tower footprint scales (r2=0.50, RMSE=1.79, bias=0.27) and distance of field tower from lidar footprint center (r2=0.63, RMSE=1.36, bias=0.0) were accounted for. Next, we mapped the spatial distribution of total LAI across the landscape and analyzed LAI variations over different land cover types. Mean values of total LAI were 1.74, 5.20, 5.41 and 5.62 over open pasture, secondary forests, regeneration forests after selective-logging and old-growth forests respectively. Lastly, we evaluated the sensitivities of our LAI retrieval model to variations in canopy/ground reflectance ratio and to waveform noise such as induced by topographic slopes. We found for both, that the effects were not significant for moderate LAI values (about 4). However model derivations of LAI might be inaccurate in areas of high-slope and high LAI (about 8) if ground return energies are low. This research suggests that large footprint waveform lidar can provide accurate vertical LAI profile estimates that do not saturate even at the high LAI levels in tropical rain forests and may be a useful tool for understanding the light transmittance within these canopies.

  19. Optical properties of aerosols over a tropical rain forest in Xishuangbanna, South Asia

    NASA Astrophysics Data System (ADS)

    Ma, Yongjing; Xin, Jinyuan; Zhang, Wenyu; Wang, Yuesi

    2016-09-01

    Observation and analysis of the optical properties of atmospheric aerosols in a South Asian tropical rain forest showed that the annual mean aerosol optical depth (AOD) and aerosol Ångström exponent (α) at 500 nm were 0.47 ± 0.30 (± value represents the standard deviation) and 1.35 ± 0.32, respectively, from 2012 to 2014, similar with that of Amazon region. Aerosol optical properties in this region varied significantly between the dry and wet seasons. The mean AOD and α were 0.50 ± 0.32 and 1.41 ± 0.28, respectively, in the dry season and 0.41 ± 0.20 and 1.13 ± 0.41 in the wet season. Because of the combustion of the rich biomass in the dry season, fine modal smoke aerosols increased, which led to a higher AOD and smaller aerosol control mode than in the wet season. The average atmospheric humidity in the wet season was 85.50%, higher than the 79.67% during the dry season. In the very damp conditions of the wet season, the aerosol control mode was relatively larger, while AOD appeared to be lower because of the effect of aerosol hygroscopic growth and wet deposition. The trajectories were similar both in dry and wet, but with different effects on the aerosol concentration. The highest AOD values 0.66 ± 0.34 (in dry) and 0.45 ± 0.21 (in wet) both occurred in continental air masses, while smaller (0.38-0.48 in dry and 0.30-0.35 in wet) in oceanic air masses. The range of AOD values during the wet season was relatively narrow (0.30-0.45), but the dry season range was wider (0.38-0.66). For the Ångström exponent, the range in the wet season (0.74-1.34) was much greater than that in the dry season (1.33-1.54).

  20. Contrasting cost-benefit strategy between lianas and trees in a tropical seasonal rain forest in southwestern China.

    PubMed

    Zhu, Shi-Dan; Cao, Kun-Fang

    2010-07-01

    Lianas are an important component of tropical forests and often abundant in open habitats, such as tree-fall gaps, forest edges, and disturbed forests. The abundance of lianas in tropical forests has been increasing as a result of global environmental change and increasing forest fragmentation. In order to understand this phenomenon in terms of leaf functional traits and to evaluate their competitive potential, we conducted a cost-benefit analysis of leaves from 18 liana species and 19 tree species in a tropical seasonal rain forest. The results revealed that lianas were scattered in a group distinct from trees along the first axis of a principal component analysis using 15 leaf ecophysiological traits, being located at the quick-return end of the leaf economics spectrum, with higher specific leaf area and photosynthetic rates (A), higher photosynthetic nitrogen (N) and phosphorus (P) use efficiencies, a lower leaf construction cost per unit leaf area (CC) and cost-benefit ratio (CC/A), and a shorter leaf life span (LLS). Trees showed the opposite trends. The results indicate that lianas can grow faster and capture resources more efficiently than trees in disturbed, open habitats. The positive relationship between LLS and CC/A revealed a trade-off between leaf construction cost and benefit over time. The 37 species analyzed had a mean foliar N/P ratio of 20, indicating that the forest was characterized by a P deficit. With an increasing atmospheric CO(2) concentration, the higher nutrient use efficiency could benefit lianas more than trees in terms of productivity, possibly also contributing to the increasing abundance of lianas in nutrient-limited tropical forests.

  1. Comparative seed ecophysiology of wild and cultivated Carica papaya trees from a tropical rain forest region in Mexico.

    PubMed

    Paz, Leoncio; Vázquez-Yanes, Carlos

    1998-04-01

    To ascertain the effects of centuries of cultivation practices on seed behavior and dormancy mechanisms, we compared seed size and germination characteristics of wild and cultivated (domesticated) populations of Carica papaya L. Germination experiments were carried out under various conditions of temperature, light, seed soaking and gibberellic acid treatments. Wild papaya seeds showed responses to treatment that are characteristic of seeds of many rain forest pioneer trees. Seeds were small and light sensitive, whereas cultivated papaya seeds were 33% larger and their light responses as well as other physiological traits indicated that cultivation had resulted in a lessening in the importance of specific environmental conditions for dormancy breaking and germination.

  2. Effect of simulated acid rain on the litter decomposition of Quercus acutissima and Pinus massoniana in forest soil microcosms and the relationship with soil enzyme activities.

    PubMed

    Wang, Congyan; Guo, Peng; Han, Guomin; Feng, Xiaoguang; Zhang, Peng; Tian, Xingjun

    2010-06-01

    With the continuing increase in human activities, ecologists are increasingly interested in understanding the effects of acid rain on litter decomposition. Two dominant litters were chosen from Zijin Mountain in China: Quercus acutissima from a broad-leaved forest and Pinus massoniana from a coniferous forest. The litters were incubated in microcosms and treated with simulated acid rain (gradient pH levels). During a six-month incubation, changes in chemical composition (i.e., lignin, total carbohydrate, and nitrogen), litter mass losses, soil pH values, and activities of degradative enzymes were determined. Results showed that litter mass losses were depressed after exposure to acid rain and the effects of acid rain on the litter decomposition rates of needles were higher than on those of leaves. Results also revealed that simulated acid rain restrained the activities of cellulase, invertase, nitrate reductase, acid phosphatase, alkaline phosphatase, polyphenol oxidase, and urease, while it enhanced the activities of catalase in most cases during the six-month decomposition process. Catalase and polyphenol oxidase were primarily responsible for litter decomposition in the broad-leaved forest, while invertase, nitrate reductase, and urease were primarily responsible for litter decomposition in the coniferous forest. The results suggest acid rain-restrained litter decomposition may be due to the depressed enzymatic activities. According to the results of this study, soil carbon in subtropical forests would accumulate as a long-term consequence of continued acid rain. This may presumably alter the balance of ecosystem carbon flux, nutrient cycling, and humus formation, which may, in turn, have multiple effects on forest ecosystems.

  3. Effect of simulated acid rain on the litter decomposition of Quercus acutissima and Pinus massoniana in forest soil microcosms and the relationship with soil enzyme activities.

    PubMed

    Wang, Congyan; Guo, Peng; Han, Guomin; Feng, Xiaoguang; Zhang, Peng; Tian, Xingjun

    2010-06-01

    With the continuing increase in human activities, ecologists are increasingly interested in understanding the effects of acid rain on litter decomposition. Two dominant litters were chosen from Zijin Mountain in China: Quercus acutissima from a broad-leaved forest and Pinus massoniana from a coniferous forest. The litters were incubated in microcosms and treated with simulated acid rain (gradient pH levels). During a six-month incubation, changes in chemical composition (i.e., lignin, total carbohydrate, and nitrogen), litter mass losses, soil pH values, and activities of degradative enzymes were determined. Results showed that litter mass losses were depressed after exposure to acid rain and the effects of acid rain on the litter decomposition rates of needles were higher than on those of leaves. Results also revealed that simulated acid rain restrained the activities of cellulase, invertase, nitrate reductase, acid phosphatase, alkaline phosphatase, polyphenol oxidase, and urease, while it enhanced the activities of catalase in most cases during the six-month decomposition process. Catalase and polyphenol oxidase were primarily responsible for litter decomposition in the broad-leaved forest, while invertase, nitrate reductase, and urease were primarily responsible for litter decomposition in the coniferous forest. The results suggest acid rain-restrained litter decomposition may be due to the depressed enzymatic activities. According to the results of this study, soil carbon in subtropical forests would accumulate as a long-term consequence of continued acid rain. This may presumably alter the balance of ecosystem carbon flux, nutrient cycling, and humus formation, which may, in turn, have multiple effects on forest ecosystems. PMID:20382410

  4. First direct landscape-scale measurement of tropical rain forest Leaf Area Index, a key driver of global primary productivity.

    PubMed

    Clark, David B; Olivas, Paulo C; Oberbauer, Steven F; Clark, Deborah A; Ryan, Michael G

    2008-02-01

    Leaf Area Index (leaf area per unit ground area, LAI) is a key driver of forest productivity but has never previously been measured directly at the landscape scale in tropical rain forest (TRF). We used a modular tower and stratified random sampling to harvest all foliage from forest floor to canopy top in 55 vertical transects (4.6 m(2)) across 500 ha of old growth in Costa Rica. Landscape LAI was 6.00 +/- 0.32 SEM. Trees, palms and lianas accounted for 89% of the total, and trees and lianas were 95% of the upper canopy. All vertical transects were organized into quantitatively defined strata, partially resolving the long-standing controversy over canopy stratification in TRF. Total LAI was strongly correlated with forest height up to 21 m, while the number of canopy strata increased with forest height across the full height range. These data are a benchmark for understanding the structure and functional composition of TRF canopies at landscape scales, and also provide insights for improving ecosystem models and remote sensing validation.

  5. [Spatial heterogeneity of soil moisture after raining at forest-grassland landscape boundary in hilly area of Loess Plateau].

    PubMed

    You, Wenzhong; Zeng, Dehui; Liu, Mingguo; Song, Xide; Ye, Yaohui; Zhang, Yong

    2005-09-01

    Soil moisture is a main factor limiting vegetation restoration in semi-arid region. In this paper, the spatial variability of different layers soil moisture after raining at the forest-grassland boundary in hilly area of Loess Plateau were studied by traditional and geostatistical analysis methods. The results showed that the moisture content in surface (0 - 10 cm) and subsurface soil layer (10 - 20 cm) of grassland was higher than that of forestland. The two layers soil moisture content at forest-grassland boundary showed a small variation but an obvious ecological distribution. By using moving split-window techniques, it was obtained that the width of edge influence in surface and subsurface layer was 8 and 6 m, respectively. Geostatistical analyses showed that the spatial distribution of two layers soil moisture had a pure nugget effect in grassland, linear model in forestland, and spherical model in forest-grassland boundary. The spatial heterogeneity of two layers soil moisture was higher at forest-grassland boundary than at forestland and grassland, which had a stronger spatial dependence and autorelation. Kriging maps expressed the spatial structural characters. The distribution of soil moisture in two layers showed a strip shape near forest edge, and a patch shape far from the edge.

  6. Tree diversity, composition, forest structure and aboveground biomass dynamics after single and repeated fire in a Bornean rain forest.

    PubMed

    Slik, J W Ferry; Bernard, Caroline S; Van Beek, Marloes; Breman, Floris C; Eichhorn, Karl A O

    2008-12-01

    Forest fires remain a devastating phenomenon in the tropics that not only affect forest structure and biodiversity, but also contribute significantly to atmospheric CO2. Fire used to be extremely rare in tropical forests, leaving ample time for forests to regenerate to pre-fire conditions. In recent decades, however, tropical forest fires occur more frequently and at larger spatial scales than they used to. We studied forest structure, tree species diversity, tree species composition, and aboveground biomass during the first 7 years since fire in unburned, once burned and twice burned forest of eastern Borneo to determine the rate of recovery of these forests. We paid special attention to changes in the tree species composition during burned forest regeneration because we expect the long-term recovery of aboveground biomass and ecosystem functions in burned forests to largely depend on the successful regeneration of the pre-fire, heavy-wood, species composition. We found that forest structure (canopy openness, leaf area index, herb cover, and stem density) is strongly affected by fire but shows quick recovery. However, species composition shows no or limited recovery and aboveground biomass, which is greatly reduced by fire, continues to be low or decline up to 7 years after fire. Consequently, large amounts of the C released to the atmosphere by fire will not be recaptured by the burned forest ecosystem in the near future. We also observed that repeated fire, with an inter-fire interval of 15 years, does not necessarily lead to a huge deterioration in the regeneration potential of tropical forest. We conclude that burned forests are valuable and should be conserved and that long-term monitoring programs in secondary forests are necessary to determine their recovery rates, especially in relation to aboveground biomass accumulation.

  7. A new rain-operated seed dispersal mechanism in Bertolonia mosenii (Melastomataceae), a Neotropical rainforest herb.

    PubMed

    Pizo, Marco A; Morellato, L Patrícia C

    2002-01-01

    Although widespread among fungi, lichens, liverworts, and mosses, seed dispersal mechanisms operated by rain are unusual among flowering plants. Generally speaking, two mechanisms are involved in seed dispersal by rains: the splash-cup and the springboard. Here we describe a new seed dispersal mechanism operated by rain in a Neotropical rainforest herb Bertolonia mosenii Cogniaux (Melastomataceae). The study was carried out at the lowland Atlantic rainforest, southeastern Brazil. We experimentally demonstrate that rain is necessary to release the seeds from the capsules through what we call "squirt-corner" seed dispersal mechanism: when a raindrop strikes the mature fruit, the water droplet forces the seeds outward to the angles (corners) of the triangular capsule and the seeds are released. As far as we know squirt-corner represents a new rain-operated seed dispersal mechanism, and a novel seed dispersal mode both for Melastomataceae and for flowering plants from Neotropical forests.

  8. Acid rain mitigation experiment shifts a forested watershed from a net sink to a net source of nitrogen.

    PubMed

    Rosi-Marshall, Emma J; Bernhardt, Emily S; Buso, Donald C; Driscoll, Charles T; Likens, Gene E

    2016-07-01

    Decades of acid rain have acidified forest soils and freshwaters throughout montane forests of the northeastern United States; the resulting loss of soil base cations is hypothesized to be responsible for limiting rates of forest growth throughout the region. In 1999, an experiment was conducted that reversed the long-term trend of soil base cation depletion and tested the hypothesis that calcium limits forest growth in acidified soils. Researchers added 1,189 kg Ca(2+) ha(-1) as the pelletized mineral wollastonite (CaSiO3) to a 12-ha forested watershed within the Hubbard Brook Experimental Forest in the White Mountains of New Hampshire. Significant increases in the pH and acid-neutralizing capacity of soils and streamwater resulted, and the predicted increase in forest growth occurred. An unanticipated consequence of this acidification mitigation experiment began to emerge a decade later, with marked increases in dissolved inorganic nitrogen (DIN) exports in streamwater from the treated watershed. By 2013, 30-times greater DIN was exported from this base-treated watershed than from adjacent reference watersheds, and DIN exports resulting from this experiment match or exceed earlier reports of inorganic N losses after severe ice-storm damage within the study watershed. The discovery that CaSiO3 enrichment can convert a watershed from a sink to a source of N suggests that numerous potential mechanisms drive watershed N dynamics and provides new insights into the influence of acid deposition mitigation strategies for both carbon cycling and watershed N export. PMID:27335456

  9. Acid rain mitigation experiment shifts a forested watershed from a net sink to a net source of nitrogen.

    PubMed

    Rosi-Marshall, Emma J; Bernhardt, Emily S; Buso, Donald C; Driscoll, Charles T; Likens, Gene E

    2016-07-01

    Decades of acid rain have acidified forest soils and freshwaters throughout montane forests of the northeastern United States; the resulting loss of soil base cations is hypothesized to be responsible for limiting rates of forest growth throughout the region. In 1999, an experiment was conducted that reversed the long-term trend of soil base cation depletion and tested the hypothesis that calcium limits forest growth in acidified soils. Researchers added 1,189 kg Ca(2+) ha(-1) as the pelletized mineral wollastonite (CaSiO3) to a 12-ha forested watershed within the Hubbard Brook Experimental Forest in the White Mountains of New Hampshire. Significant increases in the pH and acid-neutralizing capacity of soils and streamwater resulted, and the predicted increase in forest growth occurred. An unanticipated consequence of this acidification mitigation experiment began to emerge a decade later, with marked increases in dissolved inorganic nitrogen (DIN) exports in streamwater from the treated watershed. By 2013, 30-times greater DIN was exported from this base-treated watershed than from adjacent reference watersheds, and DIN exports resulting from this experiment match or exceed earlier reports of inorganic N losses after severe ice-storm damage within the study watershed. The discovery that CaSiO3 enrichment can convert a watershed from a sink to a source of N suggests that numerous potential mechanisms drive watershed N dynamics and provides new insights into the influence of acid deposition mitigation strategies for both carbon cycling and watershed N export.

  10. Atmospheric deposition and canopy exchange of anions and cations in two plantation forests under acid rain influence

    NASA Astrophysics Data System (ADS)

    Shen, Weijun; Ren, Huili; Darrel Jenerette, G.; Hui, Dafeng; Ren, Hai

    2013-01-01

    Acid deposition as a widely concerned environmental problem in China has been less studied in plantation forests compared to urban and secondary forests, albeit they constitute 1/3 of the total forested areas of the country. We measured the rainwater amount and chemistry outside and beneath the canopies of two widely distributed plantations (Acacia mangium and Dimocarpus longan) in the severe acid rain influenced Pearl River Delta region of southeastern China for two years. Our results showed that the frequency of acid rain was 96% on the basis of pH value <5.6. The volume-weighted mean (vwm) pH was 4.62 and higher in the dry (Oct.-Mar.) than in the wet (Apr.-Sep.) seasons. The major acidic anion was sulfate with vwm concentration of 140 μeq l-1 and annual deposition flux of 110.3 kg ha-1 yr-1. The major neutralizing cations were calcium (94.8 μeq l-1 and 28 kg ha-1 yr-1) and ammonium (41.2 μeq l-1 and 11.7 kg ha-1 yr-1). Over 95% of these major acidic anions and neutralizing cations were derived from anthropogenic and terrestrial sources as a result of industrial, agricultural and forestry activities. Plantation canopy had marked impacts on rainwater chemistry, with the measured anion and cation concentrations being significantly enriched in throughfall (TF) and stemflow (SF) rainwater by 1.4 (for NO) to 20-fold (for K+) compared to those in bulk precipitation (BP). Dry deposition generally contributed about 13-22% of the total deposition while canopy leaching mainly occurred for K+ (>88%) and NH (10-38%). The two tree species showed distinct impacts on rainfall redistribution and rainwater chemistry due to their differences in canopy architecture and leaf/bark texture, suggesting that species-specific effects should not be overlooked while assessing the acid deposition in forested areas.

  11. Acid rain

    SciTech Connect

    Not Available

    1985-01-01

    This report has four parts: they discuss acid rain in relation to acid soils, agriculture, forests, and aquatic ecosystems. Among findings: modern sources of acid deposition from the atmosphere for all the acid soils in the world, nor even chiefly responsible for those of northern U.S. Agriculture has its problems, but acid precipitation is probably not one of them. More research is needed to determine to what extent acid precipitation is responsible for forest declines and for smaller detrimental effects on forest growth where no damage to the foliage is evident. Many lakes and streams are extremely sensitive to added acids.

  12. Interspecific variation of photosynthesis and leaf characteristics in canopy trees of five species of Dipterocarpaceae in a tropical rain forest.

    PubMed

    Kenzo, Tanaka; Ichie, Tomoaki; Yoneda, Reiji; Kitahashi, Yoshinori; Watanabe, Yoko; Ninomiya, Ikuo; Koike, Takayoshi

    2004-10-01

    Photosynthetic rate, nitrogen concentration and morphological properties of canopy leaves were studied in 18 trees, comprising five dipterocarp species, in a tropical rain forest in Sarawak, Malaysia. Photosynthetic rate at light saturation (Pmax) differed significantly across species, varying from 7 to 18 micro mol m(-2) s(-1). Leaf nitrogen concentration and morphological properties, such as leaf blade and palisade layer thickness, leaf mass per area (LMA) and surface area of mesophyll cells per unit leaf area (Ames/A), also varied significantly across species. Among the relationships with leaf characteristics, Pmax had the strongest correlation with leaf mesophyll parameters, such as palisade cell layer thickness (r2 = 0.76, P < 0.001) and Ames/A (r2 = 0.73, P < 0.001). Leaf nitrogen concentration and Pmax per unit area also had a significant but weaker correlation (r2 = 0.46, P < 0.01), whereas Pmax had no correlation, or only weakly significant correlations, with leaf blade thickness and LMA. Shorea beccariana Burck, which had the highest P(max) of the species studied, also had the thickest palisade layer, with up to five or more layers. We conclude that interspecific variation in photosynthetic capacity in tropical rain forest canopies is influenced more by leaf mesophyll structure than by leaf thickness, LMA or leaf nitrogen concentration.

  13. Can extractive reserves save the rain forest: A ecological and socioeconomic comparison of non-timber forest product extraction systems in Peten, Guatemala, and West Kalimantan, Indonesia

    SciTech Connect

    Salafsky, N.; Dugelby, B.L.; Terborgh, J.W.

    1992-04-01

    Extractive reserves in tropical rain forests, in which only non-timber products are harvested, have been heralded by some conservationists as a means of maintaining biodiversity while providing income for local people. The study of extraction systems in Peten, Guatemala, and in West Kalimantan, Indonesia, leads to a more tempered conclusion, for while the Peten program was quite successful, the Kalimantan program was not. The study finds the success of an extractive reserve to be contingent on: (1) ecological conditions, and (2) socioeconomic and political factors. Although the study focuses on market-oriented extractive reserves, many of the issues discussed apply as well to other land uses such as the collection of non-timber forest products for household consumption or small-scale timber extraction.

  14. Alternatives to deforestation: Steps toward sustainable use of the Amazon Rain Forest

    SciTech Connect

    Anderson, A.B.

    1990-01-01

    The high rate of deforestation of the Brazilian Amazon over the past two decades has jeopardized genetic diversity, contributed to regional and global climate change, caused erosion and flooding, destroyed forest resources, spread disease, and increased poverty. This book presents a selection of papers from an international conference that explored alternatives to deforestation of tropical forests. The alternatives described include natural forest management, agroforestry systems, and forest reestablishment on degraded pastures. The book should be useful to scientists, regional planners, and the broad scientific audience.

  15. The importance of epiphytes to total rainfall interception by a tropical montane rain forest in Costa Rica

    NASA Astrophysics Data System (ADS)

    Hölscher, Dirk; Köhler, Lars; van Dijk, Albert I. J. M.; Bruijnzeel, L. A.(Sampurno)

    2004-06-01

    The abundant epiphyte vegetation of upper montane tropical rain forests, which in terms of biomass is mainly composed of non-vascular plants (mosses, liverworts and lichens), can be expected to influence the magnitude of canopy water fluxes such as rainfall interception. The objects of this study were to: (i) estimate stand canopy water storage characteristics, (ii) determine rainfall interception by the canopy as a whole, and (iii) adapt an analytical model of rainfall interception, to enable the quantification of the contribution by non-vascular epiphytes to total interception. The studied old-growth forest in the Cordillera de Talamanca, Costa Rica, was 35 m tall, dominated by oaks, and little affected by fog. The estimated leaf area index of the trees was 7.7 m 2 m -2, which combined with results from a leaf wetting experiment gave a tree leaf water storage capacity of 1.08 mm at the stand level. The biomass of non-vascular epiphytes amounted to 1.9 t ha -1 dry weight. Monthly moss water contents measured in situ ranged between 24 and 406% of moss dry weight, corresponding to a maximum moss water storage of 0.81 mm at stand level. Seasonal variation in moss water contents was reproduced satisfactorily by a running water balance model. A modified analytical interception model, which incorporated the moss water balance model, was applied. Weekly sums of observed throughfall, stemflow and interception measurements were available for comparison and amounted to 70, 2 and 28% of the associated 2150 mm of rain. The model predicted the observed values quite well and suggested that mosses contributed about 6% to the modelled interception total. Hence, the hydrological importance of epiphytes in the studied forest was rather limited despite their considerable maximum water storage capacity. This is thought to reflect the fact that under the prevailing rainfall conditions only a fraction of the potential storage is actually available.

  16. Come Rain or Shine: A Whole School Approach to Forest School

    ERIC Educational Resources Information Center

    Vandewalle, Martyn

    2010-01-01

    This article begins by describing a typical Forest School session that takes place in every class every week at The Wroxham School in Potters Bar. It goes on to outline a brief history of Forest School from its inception, its aims and ethos, and how it has been adapted for the ethos and needs of the children at Wroxham. The article also looks at…

  17. Air Pollution, Acid Rain, and the Future of Forests. Worldwatch Paper 58.

    ERIC Educational Resources Information Center

    Postel, Sandra

    This book traces centuries of human use and abuse of forest ecosystems by discussing past decades of intense burning, grazing, and timber cutting that added to the natural acidification of the soil. Air pollutants and acids generated by industrial activities worldwide are also considered. Many forests in Europe and North America now receive as…

  18. Logging impacts on forest structure and seedling dynamics in a Prioria copaifera (Fabaceae) dominated tropical rain forest (Talamanca, Costa Rica).

    PubMed

    Valverde-Barrantes, Oscar J; Rocha, Oscar J

    2014-03-01

    The factors that determine the existence of tropical forests dominated by a single species (monodominated forests) have been the subject of debate for a long time. It has been hypothesized that the low frequency of disturbances in monodominated forests and the tolerance to shade of the monodominant species are two important factors explaining the prolonged dominance of a single species. We determined the role of these two factors by examining the effects of logging activities on the floristic composition and seedling dynamics in a Prioria copaifera dominated forest in Southeastern Costa Rica. We determined the floristic composition for trees > or = 2.5cm DBH and the associated recruitment, survival and mortality of tree canopy seedlings in two sites logged two (L-02) and 12 years (L-12) prior to sampling and an unlogged forest (ULF). Our results showed that L-02 stands had lower species richness (25 species) than the L-12 and ULF stands (49 and 46 species, respectively). As expected, we found significant logging effects on the canopy structure of the altered forests, particularly when comparing the L-02 and the ULF stands. Seedling density was higher in ULF (0.96 seedlings/ m2) than in the L-02 and L-12 stands (0.322 and 0.466 seedlings/m2, respectively). However, seedling mortality was higher in the ULF stands (54%) than in the L-02 (26%) and L-12 (15%) stands. P. macroloba in L-02 was the only species with abundant regeneration under P. copaifera in L-02 stand, where it accounted for 35% of the seedlings. Despite the reduction in seedling abundance observed after logging, P. copaifera seems to maintain large seedling populations in these forests, suggesting that this species maintains its dominance after logging disturbances. Our findings challenge the hypothesis that the regeneration of monodominant species is not likely to occur under heavily disturbed canopy conditions. PMID:24912364

  19. Logging impacts on forest structure and seedling dynamics in a Prioria copaifera (Fabaceae) dominated tropical rain forest (Talamanca, Costa Rica).

    PubMed

    Valverde-Barrantes, Oscar J; Rocha, Oscar J

    2014-03-01

    The factors that determine the existence of tropical forests dominated by a single species (monodominated forests) have been the subject of debate for a long time. It has been hypothesized that the low frequency of disturbances in monodominated forests and the tolerance to shade of the monodominant species are two important factors explaining the prolonged dominance of a single species. We determined the role of these two factors by examining the effects of logging activities on the floristic composition and seedling dynamics in a Prioria copaifera dominated forest in Southeastern Costa Rica. We determined the floristic composition for trees > or = 2.5cm DBH and the associated recruitment, survival and mortality of tree canopy seedlings in two sites logged two (L-02) and 12 years (L-12) prior to sampling and an unlogged forest (ULF). Our results showed that L-02 stands had lower species richness (25 species) than the L-12 and ULF stands (49 and 46 species, respectively). As expected, we found significant logging effects on the canopy structure of the altered forests, particularly when comparing the L-02 and the ULF stands. Seedling density was higher in ULF (0.96 seedlings/ m2) than in the L-02 and L-12 stands (0.322 and 0.466 seedlings/m2, respectively). However, seedling mortality was higher in the ULF stands (54%) than in the L-02 (26%) and L-12 (15%) stands. P. macroloba in L-02 was the only species with abundant regeneration under P. copaifera in L-02 stand, where it accounted for 35% of the seedlings. Despite the reduction in seedling abundance observed after logging, P. copaifera seems to maintain large seedling populations in these forests, suggesting that this species maintains its dominance after logging disturbances. Our findings challenge the hypothesis that the regeneration of monodominant species is not likely to occur under heavily disturbed canopy conditions.

  20. Biodiversity assessment in incomplete inventories: leaf litter ant communities in several types of Bornean rain forest.

    PubMed

    Pfeiffer, Martin; Mezger, Dirk

    2012-01-01

    Biodiversity assessment of tropical taxa is hampered by their tremendous richness, which leads to large numbers of singletons and incomplete inventories in survey studies. Species estimators can be used for assessment of alpha diversity, but calculation of beta diversity is hampered by pseudo-turnover of species in undersampled plots. To assess the impact of unseen species, we investigated different methods, including an unbiased estimator of Shannon beta diversity that was compared to biased calculations. We studied alpha and beta diversity of a diverse ground ant assemblage from the Southeast Asian island of Borneo in different types of tropical forest: diperocarp forest, alluvial forest, limestone forest and heath forests. Forests varied in plant composition, geology, flooding regimes and other environmental parameters. We tested whether forest types differed in species composition and if species turnover was a function of the distance between plots at different spatial scales. As pseudo-turnover may bias beta diversity we hypothesized a large effect of unseen species reducing beta diversity. We sampled 206 ant species (25% singletons) from ten subfamilies and 55 genera. Diversity partitioning among the four forest types revealed that whereas alpha species richness and alpha Shannon diversity were significantly smaller than expected, beta-diversity for both measurements was significantly higher than expected by chance. This result was confirmed when we used the unbiased estimation of Shannon diversity: while alpha diversity was much higher, beta diversity differed only slightly from biased calculations. Beta diversity as measured with the Chao-Sørensen or Morisita-Horn Index correlated with distance between transects and between sample points, indicating a distance decay of similarity between communities. We conclude that habitat heterogeneity has a high influence on ant diversity and species turnover in tropical sites and that unseen species may have only

  1. Biodiversity Assessment in Incomplete Inventories: Leaf Litter Ant Communities in Several Types of Bornean Rain Forest

    PubMed Central

    Pfeiffer, Martin; Mezger, Dirk

    2012-01-01

    Biodiversity assessment of tropical taxa is hampered by their tremendous richness, which leads to large numbers of singletons and incomplete inventories in survey studies. Species estimators can be used for assessment of alpha diversity, but calculation of beta diversity is hampered by pseudo-turnover of species in undersampled plots. To assess the impact of unseen species, we investigated different methods, including an unbiased estimator of Shannon beta diversity that was compared to biased calculations. We studied alpha and beta diversity of a diverse ground ant assemblage from the Southeast Asian island of Borneo in different types of tropical forest: diperocarp forest, alluvial forest, limestone forest and heath forests. Forests varied in plant composition, geology, flooding regimes and other environmental parameters. We tested whether forest types differed in species composition and if species turnover was a function of the distance between plots at different spatial scales. As pseudo-turnover may bias beta diversity we hypothesized a large effect of unseen species reducing beta diversity. We sampled 206 ant species (25% singletons) from ten subfamilies and 55 genera. Diversity partitioning among the four forest types revealed that whereas alpha species richness and alpha Shannon diversity were significantly smaller than expected, beta-diversity for both measurements was significantly higher than expected by chance. This result was confirmed when we used the unbiased estimation of Shannon diversity: while alpha diversity was much higher, beta diversity differed only slightly from biased calculations. Beta diversity as measured with the Chao-Sørensen or Morisita-Horn Index correlated with distance between transects and between sample points, indicating a distance decay of similarity between communities. We conclude that habitat heterogeneity has a high influence on ant diversity and species turnover in tropical sites and that unseen species may have only

  2. The Study Commission on the Rain Forest. 9th Grade Lesson. Schools of California Online Resources for Education (SCORE): Connecting California's Classrooms to the World.

    ERIC Educational Resources Information Center

    Erickson, Toby

    In this interdisciplinary curriculum unit intended for ninth grade students, students explore in groups in a role playing format public policy questions related to rain forests. Examined in the lessons are political, economic, and ecological issues from which students are expected to make recommendations on what policy course should be followed.…

  3. El Niño droughts and their effects on tree species composition and diversity in tropical rain forests.

    PubMed

    Slik, J W F

    2004-09-01

    In this study I investigated the effects of the extreme, 1997/98 El Niño related drought on tree mortality and understorey light conditions of logged and unlogged tropical rain forest in the Indonesian province of East Kalimantan (Borneo). My objectives were to test (1) whether drought had a significant effect on tree mortality and understorey light conditions, (2) whether this effect was greater in logged than in undisturbed forest, (3) if the expected change in tree mortality and light conditions had an effect on Macaranga pioneer seedling and sapling densities, and (4) which (a)biotic factors influenced tree mortality during the drought. The 1997/1998 drought led to an additional tree mortality of 11.2, 18.1, and 22.7% in undisturbed, old logged and recently logged forest, respectively. Mortality was highest in logged forests, due to extremely high mortality of pioneer Macaranga trees (65.4%). Canopy openness was significantly higher during the drought than during the non-drought year (6.0, 8.6 and 10.4 vs 3.7, 3.8 and 3.7 in undisturbed, old logged and recently logged forest, respectively) and was positively correlated with the number of dead standing trees. The increase in light in the understorey was accompanied by a 30 to 300-fold increase in pioneer Macaranga seedling densities. Factors affecting tree mortality during drought were (1) tree species successional status, (2) tree size, and (3) tree location with respect to soil moisture. Tree density and basal area per surface unit had no influence on tree mortality during drought. The results of this study show that extreme droughts, such as those associated with El Niño events, can affect the tree species composition and diversity of tropical forests in two ways: (1) by disproportionate mortality of certain tree species groups and tree size classes, and (2) by changing the light environment in the forest understorey, thereby affecting the recruitment and growth conditions of small and immature trees. PMID

  4. HIV type 1 group M clades infecting subjects from rural villages in equatorial rain forests of Cameroon.

    PubMed

    Zhong, Ping; Burda, Sherri; Urbanski, Mateusz; Kenfack, Henriette; Tongo, Marcel; Heyndrickx, Leo; Nanfack, Aubin; Shang, Judith; Agyingi, Lucy; Zolla-Pazner, Susan; Zekeng, Leopold; Nyambi, Phillipe

    2002-12-15

    Though the HIV-1 subtypes infecting patients living in urban and semi-urban areas in Cameroon have been reported, information on the subtypes infecting patients in rural villages is lacking. To begin to understand the diversity of the HIV-1 group M subtypes infecting persons living in rural villages in the equatorial rain forest regions of Cameroon, 49 plasma samples from 14 rural villages in four provinces of Cameroon were analyzed using heteroduplex mobility analysis (HMA), DNA sequencing, and phylogenetic tree analysis on the basis of env C2V5, gag, or pol regions. Sixty-one percent of the group M infections were clade A or CRF02_AG-like as subtyped by env and gag. Of the remaining group M infections, 12% were either A or CRF02_AG-like or CRF01_AE-like in recombination with other clades; 25% were infections that were entirely non-A or non-CRF02_AG-like; and 2% were CRF11_cpx. The HIV-1 group M clades identified included A, D, F (F2), G, and H. The CRF strains identified were CRF02_AG-like, CRF01_AE-like, and CRF11_cpx. Two new intersubtype recombinant infections, H/G and A/F2, were identified. This study suggests that the HIV-1 diversity in rural villages in the equatorial rain forest of Cameroon is at least as broad as has been observed in major cities of Cameroon and that multiple HIV-1 group M subtypes are infecting persons living in the countryside of Cameroon.

  5. Complex Spatial Structure in a Population of Didymopanax pittieri, A Tree of Wind-Exposed Lower Montane Rain Forest

    NASA Technical Reports Server (NTRS)

    Lawton, Robert M.; Lawton, Robert O.

    2010-01-01

    Didymopanax pittieri is a common shade-intolerant tree colonizing treefall gaps in the elfin forests on windswept ridgecrests in the lower montane rain forests of the Cordillera de Tilarain, Costa Rica. All D. pittieri taller than > 0.5 m in a 5.2-ha elfin forested portion of a gridded study watershed in the Monteverde Cloud Forest Preserve were located, mapped, and measured. This local population of D. pittieri is spatially inhomogeneous, in that density increases with increasing wind exposure; D. pittieri are more abundant near ridge crests than lower on windward slopes. The important and ubiquitous phenomenon of spatial inhomogeneity in population density is addressed and corrected for in spatial analyses by the application of the inhomogeneous version of Ripley's K. The spatial patterns of four size classes of D. pittieri (<5 cm dbh, 5-10 cm dbh, 10-20 cm dbh, and> 20 cm dbh) were investigated. Within the large-scale trend in density driven by wind exposure, D. pittieri saplings are clumped at the scale of treefall gaps and at the scale of patches of aggregated gaps. D. pittieri 5-10 cm dbh are randomly distributed, apparently due to competitive thinning of sapling clumps during the early stages of gap-phase regeneration. D. pittieri larger than 10 cm dbh are overdispersed at a scale larger than that of patches of gaps. Natural disturbance can influence the distribution of shade intolerant tree populations at several different spatial scales, and can have discordant effects at different life history stages.

  6. Tropical Rain Forest Structure, Tree Growth and Dynamics along a 2700-m Elevational Transect in Costa Rica

    PubMed Central

    Clark, David B.; Hurtado, Johanna; Saatchi, Sassan S.

    2015-01-01

    Rapid biological changes are expected to occur on tropical elevational gradients as species migrate upslope or go extinct in the face of global warming. We established a series of 9 1-ha plots in old-growth tropical rainforest in Costa Rica along a 2700 m relief elevational gradient to carry out long-term monitoring of tropical rain forest structure, dynamics and tree growth. Within each plot we mapped, identified, and annually measured diameter for all woody individuals with stem diameters >10 cm for periods of 3-10 years. Wood species diversity peaked at 400-600 m and decreased substantially at higher elevations. Basal area and stem number varied by less than two-fold, with the exception of the 2800 m cloud forest summit, where basal area and stem number were approximately double that of lower sites. Canopy gaps extending to the forest floor accounted for <3% of microsites at all elevations. Height of highest crowns and the coefficient of variation of crown height both decreased with increasing elevation. Rates of turnover of individuals and of stand basal area decreased with elevation, but rates of diameter growth and stand basal area showed no simple relation to elevation. We discuss issues encountered in the design and implementation of this network of plots, including biased sampling, missing key meteorological and biomass data, and strategies for improving species-level research. Taking full advantage of the major research potential of tropical forest elevational transects will require sustaining and extending ground based studies, incorporation of new remotely-sensed data and data-acquisition platforms, and new funding models to support decadal research on these rapidly-changing systems. PMID:25856163

  7. Tropical rain forest structure, tree growth and dynamics along a 2700-m elevational transect in Costa Rica.

    PubMed

    Clark, David B; Hurtado, Johanna; Saatchi, Sassan S

    2015-01-01

    Rapid biological changes are expected to occur on tropical elevational gradients as species migrate upslope or go extinct in the face of global warming. We established a series of 9 1-ha plots in old-growth tropical rainforest in Costa Rica along a 2700 m relief elevational gradient to carry out long-term monitoring of tropical rain forest structure, dynamics and tree growth. Within each plot we mapped, identified, and annually measured diameter for all woody individuals with stem diameters >10 cm for periods of 3-10 years. Wood species diversity peaked at 400-600 m and decreased substantially at higher elevations. Basal area and stem number varied by less than two-fold, with the exception of the 2800 m cloud forest summit, where basal area and stem number were approximately double that of lower sites. Canopy gaps extending to the forest floor accounted for <3% of microsites at all elevations. Height of highest crowns and the coefficient of variation of crown height both decreased with increasing elevation. Rates of turnover of individuals and of stand basal area decreased with elevation, but rates of diameter growth and stand basal area showed no simple relation to elevation. We discuss issues encountered in the design and implementation of this network of plots, including biased sampling, missing key meteorological and biomass data, and strategies for improving species-level research. Taking full advantage of the major research potential of tropical forest elevational transects will require sustaining and extending ground based studies, incorporation of new remotely-sensed data and data-acquisition platforms, and new funding models to support decadal research on these rapidly-changing systems.

  8. Tropical rain forest structure, tree growth and dynamics along a 2700-m elevational transect in Costa Rica.

    PubMed

    Clark, David B; Hurtado, Johanna; Saatchi, Sassan S

    2015-01-01

    Rapid biological changes are expected to occur on tropical elevational gradients as species migrate upslope or go extinct in the face of global warming. We established a series of 9 1-ha plots in old-growth tropical rainforest in Costa Rica along a 2700 m relief elevational gradient to carry out long-term monitoring of tropical rain forest structure, dynamics and tree growth. Within each plot we mapped, identified, and annually measured diameter for all woody individuals with stem diameters >10 cm for periods of 3-10 years. Wood species diversity peaked at 400-600 m and decreased substantially at higher elevations. Basal area and stem number varied by less than two-fold, with the exception of the 2800 m cloud forest summit, where basal area and stem number were approximately double that of lower sites. Canopy gaps extending to the forest floor accounted for <3% of microsites at all elevations. Height of highest crowns and the coefficient of variation of crown height both decreased with increasing elevation. Rates of turnover of individuals and of stand basal area decreased with elevation, but rates of diameter growth and stand basal area showed no simple relation to elevation. We discuss issues encountered in the design and implementation of this network of plots, including biased sampling, missing key meteorological and biomass data, and strategies for improving species-level research. Taking full advantage of the major research potential of tropical forest elevational transects will require sustaining and extending ground based studies, incorporation of new remotely-sensed data and data-acquisition platforms, and new funding models to support decadal research on these rapidly-changing systems. PMID:25856163

  9. Changes in seed rain across Atlantic Forest fragments in Northeast Brazil

    NASA Astrophysics Data System (ADS)

    Freitas, Cíntia Gomes; Dambros, Cristian; Camargo, José Luís Campana

    2013-11-01

    The objectives of this study were to characterize the distribution of seeds in remnant fragments of the Atlantic Coastal Forest and to determine whether the species diversity, seed weight, and species composition of plant communities are altered by forest fragmentation. A transect of 100 m was established in the core of each of nine fragments of Atlantic Coastal Forest in a private sugarcane plantation in the state of Alagoas, NE Brazil, and ten seed-traps were distributed at intervals of 10 m each along the transects. For 12 consecutive months seeds were collected, dried, counted, weighed, and identified to species. Seeds were assigned to categories according to their size, dispersal mode, and shade tolerance. Multiple regression models and Mantel correlation tests were used to detect the effects of fragment size, percent forest cover nearby, distance from the source area, and distance from the nearest fragment on species diversity, mean seed weight, and species similarity. Analyses were carried out for all species and for subsets corresponding to each seed category. A total of 21,985 diaspores of 190 species were collected. Most seeds were small, shade-intolerant, and zoochoric, which corroborates other studies of fragmented forest landscapes and reflects the high disturbance levels in isolated forest remnants. Our data indicate that fragmentation processes such as habitat loss can alter species diversity and species composition by reducing habitat availability and increasing fragment isolation. We also found that large-seeded species are more affected by fragment isolation, possibly because their seed dispersers rarely cross non-forested areas between fragments, while zoochoric species are more strongly affected by fragment size and apparently more strongly associated with local edaphic conditions than with distance from seed sources.

  10. Guatemalan forest synthesis after Pleistocene aridity

    PubMed Central

    Leyden, Barbara W.

    1984-01-01

    Sediments from two lakes in the Peten Department, Guatemala, provide palynological evidence from Central America of late Pleistocene aridity and subsequent synthesis of mesic forests. Late Glacial vegetation consisted of marsh, savanna, and juniper scrub. An early Holocene temperate forest preceded a mesic tropical forest with Brosimum (ramon). Thus “primeval” rain forests of Guatemala are no older than 10,000 to 11,000 years and are considerably younger in the Peten due to Mayan disturbances. Among dated Neotropical sites, the Peten has the most mesic vegetation yet shown to have supplanted xeric vegetation present during the Pleistocene. The arid late Glacial-humid early Holocene transition appears to have been pantropical in the lowlands. The Peten was not a Pleistocene refugium for mesophytic taxa, as has been suggested. Thus genesis of extant rain forests in northern Central America and southern Mexico remains unexplained. Images PMID:16593498

  11. Using IKONOS and Aerial Videography to Validate Landsat Land Cover Maps of Central African Tropical Rain Forests

    NASA Astrophysics Data System (ADS)

    Lin, T.; Laporte, N. T.

    2003-12-01

    Compared to the traditional validation methods, aerial videography is a relatively inexpensive and time-efficient approach to collect "field" data for validating satellite-derived land cover map over large areas. In particular, this approach is valuable in remote and inaccessible locations. In the Sangha Tri-National Park region of Central Africa, where road access is limited to industrial logging sites, we are using IKONOS imagery and aerial videography to assess the accuracy of Landsat-derived land cover maps. As part of a NASA Land Cover Land Use Change project (INFORMS) and in collaboration with the Wildlife Conservation Society in the Republic of Congo, over 1500km of aerial video transects were collected in the Spring of 2001. The use of MediaMapper software combined with a VMS 200 video mapping system enabled the collection of aerial transects to be registered with geographic locations from a Geographic Positioning System. Video frame were extracted, visually interpreted, and compared to land cover types mapped by Landsat. We addressed the limitations of accuracy assessment using aerial-base data and its potential for improving vegetation mapping in tropical rain forests. The results of the videography and IKONOS image analysis demonstrate the utility of very high resolution imagery for map validation and forest resource assessment.

  12. Effects of liming on forage availability and nutrient content in a forest impacted by acid rain.

    PubMed

    Pabian, Sarah E; Ermer, Nathan M; Tzilkowski, Walter M; Brittingham, Margaret C

    2012-01-01

    Acidic deposition and subsequent forest soil acidification and nutrient depletion can affect negatively the growth, health and nutrient content of vegetation, potentially limiting the availability and nutrient content of forage for white-tailed deer (Odocoileus virginianus) and other forest herbivores. Liming is a mitigation technique that can be used to restore forest health in acidified areas, but little is known about how it affects the growth or nutrient content of deer forage. We examined the effects of dolomitic limestone application on the growth and chemical composition of understory plants in an acidified forest in central Pennsylvania, with a focus on vegetative groups included as white-tailed deer forage. We used a Before-After-Control-Impact study design with observations 1 year before liming and up to 5 years post-liming on 2 treated and 2 untreated 100-ha sites. Before liming, forage availability and several nutrients were below levels considered optimal for white-tailed deer, and many vegetative characteristics were related to soil chemistry. We observed a positive effect of liming on forb biomass, with a 2.7 fold increase on limed sites, but no biomass response in other vegetation groups. We observed positive effects of liming on calcium and magnesium content and negative effects on aluminum and manganese content of several plant groups. Responses to liming by forbs and plant nutrients show promise for improving vegetation health and forage quality and quantity for deer.

  13. Effects of Liming on Forage Availability and Nutrient Content in a Forest Impacted by Acid Rain

    PubMed Central

    Pabian, Sarah E.; Ermer, Nathan M.; Tzilkowski, Walter M.; Brittingham, Margaret C.

    2012-01-01

    Acidic deposition and subsequent forest soil acidification and nutrient depletion can affect negatively the growth, health and nutrient content of vegetation, potentially limiting the availability and nutrient content of forage for white-tailed deer (Odocoileus virginianus) and other forest herbivores. Liming is a mitigation technique that can be used to restore forest health in acidified areas, but little is known about how it affects the growth or nutrient content of deer forage. We examined the effects of dolomitic limestone application on the growth and chemical composition of understory plants in an acidified forest in central Pennsylvania, with a focus on vegetative groups included as white-tailed deer forage. We used a Before-After-Control-Impact study design with observations 1 year before liming and up to 5 years post-liming on 2 treated and 2 untreated 100-ha sites. Before liming, forage availability and several nutrients were below levels considered optimal for white-tailed deer, and many vegetative characteristics were related to soil chemistry. We observed a positive effect of liming on forb biomass, with a 2.7 fold increase on limed sites, but no biomass response in other vegetation groups. We observed positive effects of liming on calcium and magnesium content and negative effects on aluminum and manganese content of several plant groups. Responses to liming by forbs and plant nutrients show promise for improving vegetation health and forage quality and quantity for deer. PMID:22761890

  14. Effects of liming on forage availability and nutrient content in a forest impacted by acid rain.

    PubMed

    Pabian, Sarah E; Ermer, Nathan M; Tzilkowski, Walter M; Brittingham, Margaret C

    2012-01-01

    Acidic deposition and subsequent forest soil acidification and nutrient depletion can affect negatively the growth, health and nutrient content of vegetation, potentially limiting the availability and nutrient content of forage for white-tailed deer (Odocoileus virginianus) and other forest herbivores. Liming is a mitigation technique that can be used to restore forest health in acidified areas, but little is known about how it affects the growth or nutrient content of deer forage. We examined the effects of dolomitic limestone application on the growth and chemical composition of understory plants in an acidified forest in central Pennsylvania, with a focus on vegetative groups included as white-tailed deer forage. We used a Before-After-Control-Impact study design with observations 1 year before liming and up to 5 years post-liming on 2 treated and 2 untreated 100-ha sites. Before liming, forage availability and several nutrients were below levels considered optimal for white-tailed deer, and many vegetative characteristics were related to soil chemistry. We observed a positive effect of liming on forb biomass, with a 2.7 fold increase on limed sites, but no biomass response in other vegetation groups. We observed positive effects of liming on calcium and magnesium content and negative effects on aluminum and manganese content of several plant groups. Responses to liming by forbs and plant nutrients show promise for improving vegetation health and forage quality and quantity for deer. PMID:22761890

  15. Potential and Limitations of Satellite Data to Identify Deaths of Individual Trees in a Central American Tropical Rain Forest

    NASA Astrophysics Data System (ADS)

    Thomas, R. Q.; Kellner, J. R.; Peart, D. R.

    2005-12-01

    Logistical constraints on sample size and spatial scale limit individual-based field research on tropical trees. With remote sensing data, we may escape these limitations if fates of individuals can be tracked rigorously. We assessed the potential of readily available, commercial satellite data (QuickBird, 0.7 m pixels) obtained in 2003, to track the fate of individual crowns (> 40 m height) in tropical rain forest at La Selva, Costa Rica. The positions and shapes of these crowns in 1997 had been established using small-footprint LiDAR data with field verification. We focused first on a subset (n=180) of trees monitored in the field over the period 1997-2003. For the 60% of those trees whose crown positions and shapes could be tracked with confidence in the satellite image, we correctly recorded all 3 actual deaths. But we also incorrectly assigned 4 additional deaths to living individuals, due to the abundance of dark pixels in their crown areas. For the 40% of field-monitored trees for which our tracking in the satellite data was less confident (due to lack of image clarity), we correctly identified the one real death event, but incorrectly assigned 6 additional deaths to living trees. Thus, for the field-monitored trees, we grossly overestimated mortality in the satellite image (by 350%). Although currently available high resolution satellite imagery was not adequate for reliable monitoring of individuals, even for the largest forest trees, time series satellite data, rather than time series LiDAR to satellite data, might provide unbiased estimates of overall tree mortality rates if errors compensate. Satellite data may be also be useful as a labor and time saving complement to fieldwork on individual forest trees.

  16. Carbon budget of Nyungwe Tropical Montane Rain Forest in Central Africa

    NASA Astrophysics Data System (ADS)

    Nyirambangutse, B.; Zibera, E.; Uwizeye, F. K.; Hansson, L.; Nsabimana, D.; Pleijel, H.; Uddling, J.; Wallin, G.

    2015-12-01

    African tropical rainforests host rich biodiversity and play many roles at different scales such as local, regional and global, in the functioning of the earth system. Despite that the African tropical forests are the world's second largest, it has been neglected in terms of understanding the storage and fluxes of carbon and other nutrients. The question of whether this biome is a net sink or source of atmospheric CO2 is still not answered, and little is known concerning the climate change response. Tropical montane forests are even more poorly sampled compared with their importance. Deeper understanding of these ecosystems is required to provide insights on how they might react under global change. To answer questions related to these issues for African tropical montane forests, 15 permanent 0.5 ha plots were established in 2011 in Nyungwe tropical montane rainforest gazetted as a National Park to protect its extensive floral and faunal diversity. The plots are arranged along an east-westerly transect and includes both primary and secondary forest communities. The study is connected to the global ecosystem monitoring network (GEM, http://gem.tropicalforests.ox.ac.uk/). The aim is to characterize spatial and temporal heterogeneity of carbon and nutrient dynamics processes. The role of microclimate, topography, human disturbances, and plant species to the variability of these pools and processes will be explored. We compare stocks and fluxes of carbon and nutrients of the secondary and primary forest communities. The carbon stock are determined by an inventory of height and diameter at breast height (dbh) of all trees with a dbh above 5 cm, wood density, biomass of understory vegetation, leaf area index, standing and fallen dead wood, fine root biomass and organic content of various soil layers (litter, organic and mineral soil down to 45 cm depth). The carbon fluxes are determined by measurements of photosynthesis and respiration of leaves, above and below ground

  17. Methyl chloride and isoprene emissions from tropical rain forest in Southeast Asia

    NASA Astrophysics Data System (ADS)

    Saito, Takuya; Yokouchi, Yoko; Kosugi, Yoshiko; Tani, Makoto; Philip, Elizabeth; Okuda, Toshinori

    2008-10-01

    Methyl chloride (CH3Cl) fluxes were investigated at leaf and forest-canopy scales in tropical forests in Malaysia. Screening of CH3Cl-emitting species showed that 21% of 117 tree species were CH3Cl emitters; the percentage was markedly higher for dipterocarps (66%) than non-dipterocarps (6%). The dipterocarp-derived CH3Cl was characterized by high emissions (median: 0.03 μg g-1 h-1) and low stable carbon isotope ratios (mean: -88.9 +/- 11.0‰). Measurements of CH3Cl above the canopy showed a slight decrease in the mixing ratios with increasing height. These values were used to estimate the canopy-scale flux of about 14 μg m-2 h-1, comparable to that extrapolated from the leaf-scale emissions. Using the canopy-scale flux, global CH3Cl emission by tropical forests was estimated to be 1.3 Tg yr-1, representing approximately 30% of the global emissions. Above-canopy measurements were also made for isoprene, with a mean flux of 1.2 mg m-2 h-1.

  18. On the relationships between leaf-litter lignin and net primary productivity in tropical rain forests.

    PubMed

    Kitayama, Kanehiro; Suzuki, Shizuo; Hori, Masato; Takyu, Masaaki; Aiba, Shin-Ichiro; Majalap-Lee, Noreen; Kikuzawa, Kihachiro

    2004-07-01

    We investigated if tropical rainforest trees produced more-lignified leaves in less productive environments using forests on Mount Kinabalu, Borneo. Our investigation was based on two earlier suggestions that slower litter decomposition occurs under less productive forests and that trees under resource limitation invest a large amount of carbon as lignin as a defense substance to minimize the loss from herbivores. When nine forests at different altitudes (700-3100 m) and soil conditions (derived from sedimentary or ultrabasic rocks) but with the same gentle relief position were compared, the concentrations of leaf-litter lignin were positively correlated with litterfall rates and leaf-litter nitrogen concentrations. These patterns would be reinforced in intact leaves if the effects of resorption at the time of leaf shedding were taken into account, because greater magnitude of resorption of mobile elements but not of lignin would occur in less productive environments (i.e. dilution of lignin in intact leaves). These results did not support earlier suggestions to explain the variation of leaf-litter lignin. Instead, we suggest that lower lignin contents are adaptive to recycle minerals without retarding decomposition in less productive environments.

  19. Direct damage to vegetation caused by acid rain and polluted cloud: definition of critical levels for forest trees.

    PubMed

    Cape, J N

    1993-01-01

    The concept of critical levels was developed in order to define short-term and long-term average concentrations of gaseous pollutants above which plants may be damaged. Although the usual way in which pollutants in precipitation (wet deposition) influence vegetation is by affecting soil processes, plant foliage exposed to fog and cloud, which often contain much greater concentrations of pollutant ions than rain, may be damaged directly. The idea of a critical level has been extended to define concentrations of pollutants in wet deposition above which direct damage to plants is likely. Concentrations of acidity and sulphate measured in mountain and coastal cloud are summarised. Vegetation at risk of injury is identified as montane forest growing close to the cloud base, where ion concentrations are highest. The direct effects of acidic precipitation on trees are reviewed, based on experimental exposure of plants to simulated acidic rain, fog or mist. Although most experiments have reported results in terms of pH (H(+) concentration), the accompanying anion is important, with sulphate being more damaging than nitrate. Both conifers and broadleaved tree seedlings showing subtle changes in the structural characteristics of leaf surfaces after exposure to mist or rain at or about pH 3.5, or sulphate concentration of 150 micromol litre(-1). Visible lesions on leaf surfaces occur at around pH 3 (500 micromol litre(-1) sulphate), broadleaved species tending to be more sensitive than conifers. Effects on photosynthesis and water relations, and interactions with other stresses (e.g. frost), have usually been observed only for treatments which have also caused visible injury to the leaf surface. Few experiments on the direct effects of polluted cloud have been conducted under field conditions with mature trees, which unlike seedlings in controlled conditions, may suffer a growth reduction in the absence of visible injury. Although leaching of cations (Ca(2+), Mg(2+), K(+)) is

  20. Direct damage to vegetation caused by acid rain and polluted cloud: definition of critical levels for forest trees.

    PubMed

    Cape, J N

    1993-01-01

    The concept of critical levels was developed in order to define short-term and long-term average concentrations of gaseous pollutants above which plants may be damaged. Although the usual way in which pollutants in precipitation (wet deposition) influence vegetation is by affecting soil processes, plant foliage exposed to fog and cloud, which often contain much greater concentrations of pollutant ions than rain, may be damaged directly. The idea of a critical level has been extended to define concentrations of pollutants in wet deposition above which direct damage to plants is likely. Concentrations of acidity and sulphate measured in mountain and coastal cloud are summarised. Vegetation at risk of injury is identified as montane forest growing close to the cloud base, where ion concentrations are highest. The direct effects of acidic precipitation on trees are reviewed, based on experimental exposure of plants to simulated acidic rain, fog or mist. Although most experiments have reported results in terms of pH (H(+) concentration), the accompanying anion is important, with sulphate being more damaging than nitrate. Both conifers and broadleaved tree seedlings showing subtle changes in the structural characteristics of leaf surfaces after exposure to mist or rain at or about pH 3.5, or sulphate concentration of 150 micromol litre(-1). Visible lesions on leaf surfaces occur at around pH 3 (500 micromol litre(-1) sulphate), broadleaved species tending to be more sensitive than conifers. Effects on photosynthesis and water relations, and interactions with other stresses (e.g. frost), have usually been observed only for treatments which have also caused visible injury to the leaf surface. Few experiments on the direct effects of polluted cloud have been conducted under field conditions with mature trees, which unlike seedlings in controlled conditions, may suffer a growth reduction in the absence of visible injury. Although leaching of cations (Ca(2+), Mg(2+), K(+)) is

  1. Photosynthesis and growth of two rain forest species in simulated gaps under elevated CO{sub 2}

    SciTech Connect

    Roden, J.S.; Wiggins, D.J.; Ball, M.C.

    1997-03-01

    Two species common to the temperate rain forests of New South Wales, Australia (Doryphora sassafras and Acmena smithii) were grown for 2 wk in either ambient (350 {mu}L/L) or elevated (700 {mu}L/L) CO{sub 2} concentrations and low light (30 {mu}mol photons{center_dot}m{sup {minus}2}{center_dot}s{sup {minus}1}) after which the seedlings were exposed for over 9 wk to a midday 2-h highlight period (1250 {mu}mol photons{center_dot}m{sup {minus}2}{center_dot}s{sup {minus}1}, maximum) to simulate a tree fall gap. For both species, plants grown in elevated CO{sub 2} had greater biomass than plants grown in ambient CO{sub 2}. However, relative increases in biomass were greater in Acmena, an early-successional species, than Doryphora, a late-successional species. Recovery in quantum efficiencies over time was observed for Doryphora, implying physiological acclimation to the new light environment. Doryphora plants grown in elevated CO{sub 2} had lower values of F{sub v}/F{sub m} than plants grown in ambient CO{sub 2}. Although exposure to the simulated tree fall gap dramatically increased the conversion of pigments of the xanthophyll cycle, as well as increased the total pool size of xanthophyll cycle pigments relative to total chlorophyll concentration, there were no differences in either parameter between co{sub 2} treatments. Leaves of Doryphora and those seedlings grown in elevated CO{sub 2} had greater starch concentrations than Acmena and those seedlings grown in elevated CO{sub 2} had greater starch concentrations than Acmena and those seedlings grown in ambient CO{sub 2}, respectively. The reduction in quantum efficiencies for plants grown in elevated CO{sub 2} and exposed to a simulated tree fall gap is discussed in the context of the importance of gap phase regeneration for species in rain forest ecosystems and the potential effects of global change on those processes. 37 refs., 4 figs., 2 tabs.

  2. High population density of black-handed spider monkeys (Ateles geoffroyi) in Costa Rican lowland wet forest.

    PubMed

    Weghorst, Jennifer A

    2007-04-01

    The main objective of this study was to estimate the population density and demographic structure of spider monkeys living in wet forest in the vicinity of Sirena Biological Station, Corcovado National Park, Costa Rica. Results of a 14-month line-transect survey showed that spider monkeys of Sirena have one of the highest population densities ever recorded for this genus. Density estimates varied, however, depending on the method chosen to estimate transect width. Data from behavioral monitoring were available to compare density estimates derived from the survey, providing a check of the survey's accuracy. A combination of factors has most probably contributed to the high density of Ateles, including habitat protection within a national park and high diversity of trees of the fig family, Moraceae. Although natural densities of spider monkeys at Sirena are substantially higher than those recorded at most other sites and in previous studies at this site, mean subgroup size and age ratios were similar to those determined in previous studies. Sex ratios were similar to those of other sites with high productivity. Although high densities of preferred fruit trees in the wet, productive forests of Sirena may support a dense population of spider monkeys, other demographic traits recorded at Sirena fall well within the range of values recorded elsewhere for the species.

  3. High population density of black-handed spider monkeys (Ateles geoffroyi) in Costa Rican lowland wet forest.

    PubMed

    Weghorst, Jennifer A

    2007-04-01

    The main objective of this study was to estimate the population density and demographic structure of spider monkeys living in wet forest in the vicinity of Sirena Biological Station, Corcovado National Park, Costa Rica. Results of a 14-month line-transect survey showed that spider monkeys of Sirena have one of the highest population densities ever recorded for this genus. Density estimates varied, however, depending on the method chosen to estimate transect width. Data from behavioral monitoring were available to compare density estimates derived from the survey, providing a check of the survey's accuracy. A combination of factors has most probably contributed to the high density of Ateles, including habitat protection within a national park and high diversity of trees of the fig family, Moraceae. Although natural densities of spider monkeys at Sirena are substantially higher than those recorded at most other sites and in previous studies at this site, mean subgroup size and age ratios were similar to those determined in previous studies. Sex ratios were similar to those of other sites with high productivity. Although high densities of preferred fruit trees in the wet, productive forests of Sirena may support a dense population of spider monkeys, other demographic traits recorded at Sirena fall well within the range of values recorded elsewhere for the species. PMID:17265010

  4. Measurements of soil and canopy exchange rates in the Amazon rain forest using Rn-222

    NASA Technical Reports Server (NTRS)

    Trumbore, S. E.; Keller, M.; Wofsy, S. C.; Da Costa, J. M.

    1990-01-01

    Measurements were taken of the emission of Rn-222 from Amazon forest rocks and soils and used as a tracer of ventilation of the forest canopy layer at night. It was determined that the greatest resistance to transfer of trace gases from the soil to the atmosphere lies in the soil air space. Profiles of Rn-222 and CO2 showed steepest concentration gradients in the layer between 0 and 3 m above soil surface. Aerodynamic resistances calculated for this layer from Rn-222 and CO2 varied from 1.6 to 18 s/cm, with greater resistance during the afternoon than at night. The resistance to exchange with air from the entire 41 m layer below the canopy averaged 4.8 s/cm during 13 nights of CO2 profiles. The calculated average time to flush the layer below 41 m is 5.5 hr, and it is concluded that this indicates that significant exchange occurs despite nocturnal stratification.

  5. Distribution of bioluminescent fungi across old-growth and secondary tropical rain forest in Costa Rica.

    PubMed

    Seas-Carvajal, Carolina; Avalos, Gerardo

    2013-06-01

    Most research on bioluminescent fungi is concentrated on their taxonomic relationships, while the basics of their natural history and ecological relationships are poorly understood. In this study, we compared the distribution of bioluminescent fungi between old-growth and secondary forest as related to four different soil types at the tropical rainforest of La Selva Biological Station in Costa Rica. The study was conducted during the wet season of 2009. Bioluminescent fungi were sought following eight different transects distributed evenly in old-growth and secondary forests across four different soil types, covering an area of 9 420m2. We found fungi in four different substrates: litter, fallen branches, dead trunks, and roots, for a total of 61 samples. Correspondence analysis showed that the occurrence of fungi and soil types were related (inertia = 0.21, p = 0.071). We found a significant relationship between the presence of fungi and the distribution of soil types (X2 = 18.89, df = 9, p = 0.026). We found only three samples with fruiting bodies, two of which had Mycena and the other had one fungus of the order Xylariales (possibly Hypoxylon sp., Kretzschmariella sp., Xylaria sp.). Future work will concentrate on exploring other aspects of their ecology, such as their dispersal and substrate preference. This information will facilitate field identification and will foster more research on the distribution, seasonality, reproductive phenology and ecological requirements of this group of Fungi.

  6. An instrument design and sample strategy for measuring soil respiration in the coastal temperate rain forest

    NASA Astrophysics Data System (ADS)

    Nay, S. M.; D'Amore, D. V.

    2009-12-01

    The coastal temperate rainforest (CTR) along the northwest coast of North America is a large and complex mosaic of forests and wetlands located on an undulating terrain ranging from sea level to thousands of meters in elevation. This biome stores a dynamic portion of the total carbon stock of North America. The fate of the terrestrial carbon stock is of concern due to the potential for mobilization and export of this store to both the atmosphere as carbon respiration flux and ocean as dissolved organic and inorganic carbon flux. Soil respiration is the largest export vector in the system and must be accurately measured to gain any comprehensive understanding of how carbon moves though this system. Suitable monitoring tools capable of measuring carbon fluxes at small spatial scales are essential for our understanding of carbon dynamics at larger spatial scales within this complex assemblage of ecosystems. We have adapted instrumentation and developed a sampling strategy for optimizing replication of soil respiration measurements to quantify differences among spatially complex landscape units of the CTR. We start with the design of the instrument to ease the technological, ergonomic and financial barriers that technicians encounter in monitoring the efflux of CO2 from the soil. Our sampling strategy optimizes the physical efforts of the field work and manages for the high variation of flux measurements encountered in this difficult environment of rough terrain, dense vegetation and wet climate. Our soil respirometer incorporates an infra-red gas analyzer (LiCor Inc. LI-820) and an 8300 cm3 soil respiration chamber; the device is durable, lightweight, easy to operate and can be built for under $5000 per unit. The modest unit price allows for a multiple unit fleet to be deployed and operated in an intensive field monitoring campaign. We use a large 346 cm2 collar to accommodate as much micro spatial variation as feasible and to facilitate repeated measures for tracking

  7. Effects of calcium on seed germination, seedling growth and photosynthesis of six forest tree species under simulated acid rain.

    PubMed

    Liu, Ting-Wu; Wu, Fei-Hua; Wang, Wen-Hua; Chen, Juan; Li, Zhen-Ji; Dong, Xue-Jun; Patton, Janet; Pei, Zhen-Ming; Zheng, Hai-Lei

    2011-04-01

    We selected six tree species, Pinus massoniana Lamb., Cryptomeria fortunei Hooibr. ex Otto et Dietr., Cunninghamia lanceolata (Lamb.) Hook., Liquidambar formosana Hance, Pinus armandii Franch. and Castanopsis chinensis Hance, which are widely distributed as dominant species in the forest of southern China where acid deposition is becoming more and more serious in recent years. We investigated the effects and potential interactions between simulated acid rain (SiAR) and three calcium (Ca) levels on seed germination, radicle length, seedling growth, chlorophyll content, photosynthesis and Ca content in leaves of these six species. We found that the six species showed different responses to SiAR and different Ca levels. Pinus armandii and C. chinensis were very tolerant to SiAR, whereas the others were more sensitive. The results of significant SiAR × Ca interactions on different physiological parameters of the six species demonstrate that additional Ca had a dramatic rescue effect on the seed germination and seedling growth for the sensitive species under SiAR. Altogether, we conclude that the negative effects of SiAR on seed germination, seedling growth and photosynthesis of the four sensitive species could be ameliorated by Ca addition. In contrast, the physiological processes of the two tolerant species were much less affected by both SiAR and Ca treatments. This conclusion implies that the degree of forest decline caused by long-term acid deposition may be attributed not only to the sensitivity of tree species to acid deposition, but also to the Ca level in the soil.

  8. Effects of land clearing techniques and tillage systems on runoff and soil erosion in a tropical rain forest in Nigeria.

    PubMed

    Ehigiator, O A; Anyata, B U

    2011-11-01

    This work reports runoff and soil loss from each of 14 sub-watersheds in a secondary rain forest in south-western Nigeria. The impact of methods of land clearing and post-clearing management on runoff and soil erosion under the secondary forest is evaluated. These data were acquired eighteen years after the deforestation of primary vegetation during the ' West bank' project of the International Institute for Tropical Agriculture (IITA). These data are presented separately for each season; however, statistical analyses for replicates were not conducted due to differences in their past management. Soil erosion was affected by land clearing and tillage methods. The maximum soil erosion was observed on sub-watersheds that were mechanically cleared with tree-pusher/root-rake attachments and tilled conventionally. A high rate of erosion was observed even when graded-channel terraces were constructed to minimize soil erosion. In general there was much less soil erosion on manually cleared than on mechanically cleared sub-watersheds (2.5 t ha(-1) yr(-1) versus 13.8 t ha(-1) yr(-1)) and from the application of no-tillage methods than from conventionally plowed areas (6.5 t ha(-1) yr(-1) versus 12.1 t ha(-1) yr(-1)). The data indicate that tillage methods and appropriate management of soils and crops play an important role in soil and water conservation and in decreasing the rate of decline of soil quality.

  9. Effects of calcium on seed germination, seedling growth and photosynthesis of six forest tree species under simulated acid rain.

    PubMed

    Liu, Ting-Wu; Wu, Fei-Hua; Wang, Wen-Hua; Chen, Juan; Li, Zhen-Ji; Dong, Xue-Jun; Patton, Janet; Pei, Zhen-Ming; Zheng, Hai-Lei

    2011-04-01

    We selected six tree species, Pinus massoniana Lamb., Cryptomeria fortunei Hooibr. ex Otto et Dietr., Cunninghamia lanceolata (Lamb.) Hook., Liquidambar formosana Hance, Pinus armandii Franch. and Castanopsis chinensis Hance, which are widely distributed as dominant species in the forest of southern China where acid deposition is becoming more and more serious in recent years. We investigated the effects and potential interactions between simulated acid rain (SiAR) and three calcium (Ca) levels on seed germination, radicle length, seedling growth, chlorophyll content, photosynthesis and Ca content in leaves of these six species. We found that the six species showed different responses to SiAR and different Ca levels. Pinus armandii and C. chinensis were very tolerant to SiAR, whereas the others were more sensitive. The results of significant SiAR × Ca interactions on different physiological parameters of the six species demonstrate that additional Ca had a dramatic rescue effect on the seed germination and seedling growth for the sensitive species under SiAR. Altogether, we conclude that the negative effects of SiAR on seed germination, seedling growth and photosynthesis of the four sensitive species could be ameliorated by Ca addition. In contrast, the physiological processes of the two tolerant species were much less affected by both SiAR and Ca treatments. This conclusion implies that the degree of forest decline caused by long-term acid deposition may be attributed not only to the sensitivity of tree species to acid deposition, but also to the Ca level in the soil. PMID:21470980

  10. A forensic entomology case from the Amazon rain forest of Brazil.

    PubMed

    Pujol-Luz, José R; Marques, Helder; Ururahy-Rodrigues, Alexandre; Rafael, José Albertino; Santana, Fernando H A; Arantes, Luciano C; Constantino, Reginaldo

    2006-09-01

    The first case of application of forensic entomology in the Brazilian Amazonia is described. The corpses of 26 men were found in the rainforest in Rondonia State, Brazil. Fly larvae collected on the bodies during autopsy were identified as Paralucilia fulvinota (Diptera, Calliphoridae). No data or specimens were collected at the crime scene. At the laboratory, the larvae developed into pupae in 58 h and into adults in 110.5 h. The total development time for P. fulvinota was measured in field experiments inside the forest. The age of the larvae when collected from the bodies was estimated as the difference between the time required for them to become adults and the total development time for this species. The estimated age of the maggots and the minimum postmortem interval was 5.7 days.

  11. Relating tree growth to rainfall in Bolivian rain forests: a test for six species using tree ring analysis.

    PubMed

    Brienen, Roel J W; Zuidema, Pieter A

    2005-11-01

    Many tropical regions show one distinct dry season. Often, this seasonality induces cambial dormancy of trees, particularly if these belong to deciduous species. This will often lead to the formation of annual rings. The aim of this study was to determine whether tree species in the Bolivian Amazon region form annual rings and to study the influence of the total amount and seasonal distribution of rainfall on diameter growth. Ring widths were measured on stem discs of a total of 154 trees belonging to six rain forest species. By correlating ring width and monthly rainfall data we proved the annual character of the tree rings for four of our study species. For two other species the annual character was proved by counting rings on trees of known age and by radiocarbon dating. The results of the climate-growth analysis show a positive relationship between tree growth and rainfall in certain periods of the year, indicating that rainfall plays a major role in tree growth. Three species showed a strong relationship with rainfall at the beginning of the rainy season, while one species is most sensitive to the rainfall at the end of the previous growing season. These results clearly demonstrate that tree ring analysis can be successfully applied in the tropics and that it is a promising method for various research disciplines.

  12. Composition of soil testate amoebae communities: their structure and modifications in the temperate rain forests of New Zealand and Tasmania.

    PubMed

    Bamforth, Stuart S

    2015-01-01

    A study of the temperate rain forests of New Zealand and Tasmania showed that their soil testate amoebae communities are composed of five groups of taxa: (1) seven taxa characteristic of wet acidic soils and Sphagnum peatlands (i.e., Amphitemidae, Apodera, Alcodera, Certesella, Cyphoderia, Placocista); (2) a group of 16 species of predatory Nebelids and Heleopera spp., characteristic of Sphagnum and rainforests; (3) a group of 17 species of litter and soil Euglypha, excluding the smallest ones; (4) a diverse population of other morphotypes common in other biomes; and (5) a population of small euryoecious taxa - Cryptodifflugia and Pseudodifflugia spp., Euglypha rotunda, E. laevis, Corythion and Trinema spp. This fifth group, with other r-selected protists (e.g., colpodid ciliates) appears in all habitats. Soil testate communities of other rainforests are composed of the same five groups and are distinguished by the first three assemblages. The fourth and fifth groups, often supplemented with a few Euglypha species, comprise the soil testate amoebae of other biomes. Nebelids and Heleopera, incorporating prey idiosomes into their shells, add an additional link to the role of Euglyphids in the silica cycle. Three Gondwanan Nebelid genera, Apodera, Alcodera, and Certesella were frequently observed, and the discovery of Alcodera cockayni in Tasmania extends its recorded distribution in the Southern Hemisphere.

  13. A new species of small-eared shrew (Mammalia, Eulipotyphla, Cryptotis) from the Lacandona rain forest, Mexico

    USGS Publications Warehouse

    Guevara, Lázaro; Sánchez-Cordero, Víctor; León-Paniagua, Livia; Woodman, Neal

    2014-01-01

    The diversity and distribution of mammals in the American tropics remain incompletely known. We describe a new species of small-eared shrew (Soricidae, Cryptotis) from the Lacandona rain forest, Chiapas, southern Mexico. The new species is distinguished from other species of Cryptotis on the basis of a unique combination of pelage coloration, size, dental, cranial, postcranial, and external characters, and genetic distances. It appears most closely related to species in the Cryptotis nigrescens species group, which occurs from southern Mexico to montane regions of Colombia. This discovery is particularly remarkable because the new species is from a low-elevation habitat (approximately 90 m), whereas most shrews in the region are restricted to higher elevations, typically > 1,000 m. The only known locality for the new shrew is in one of the last areas in southern Mexico where relatively undisturbed tropical vegetation is still found. The type locality is protected by the Mexican government as part of the Yaxchilán Archaeological Site on the border between Mexico and Guatemala.

  14. Vertical Accretion of the Rain Forest Floodplains and Levees: the Formation of Rias from Interaction of Black and White River Types in the Amazon River System.

    NASA Astrophysics Data System (ADS)

    Ori, G.; Franzinelli, E.

    2006-12-01

    The Amazon river system is dominated by the presence of rias, that is plaeovalleys paretially filled by sediment and harbouring almost standing bodies of water. Since the seminal work of Harald Sioli, it has been clear the paleovalleys have been formed in rivers (black type) poor in sediment and rich in organic matter during low stand periods of the sea level. Subsequently, the rivers rich in sediment (white type) damming of their mouths by the vertical accretion of the rivers rich in sediments (white type). This pattern is present in other rain forest fluvial systems and a good example is the Murray Lake in Papua New Guinea. These relations show that of the flood plain in tropical rain forest systems is strongly dominated by vertical accretion. This fact is also confirmed by the ubiquitous presence of levees inside channels (e.g. Rio Trombettas). Levees accrete vertically by the addition of single layers of sediment mostly entrapped by vegetation. The formation of permanent crevasse splays is also contributing to the levee accretion. Secondary channels are perched over the floodplain interface and totally bounded by levees. Consequently, the floodplain is dominated by lakes, permanent crevasse splays and levees assembled in vertical stacked bodies. The geological record shows examples of rain forest floodplains with similar facies and stratigraphic patterns..

  15. Evidence for coal forest refugia in the seasonally dry Pennsylvanian tropical lowlands of the Illinois Basin, USA

    PubMed Central

    Stevenson, Robert A.; Van Hoof, Thomas B.; Mander, Luke

    2014-01-01

    The Moscovian plant macroflora at Cottage Grove southeastern Illinois, USA, is a key example of Pennsylvanian (323–299 Million years ago) dryland vegetation. There is currently no palynological data from the same stratigraphic horizons as the plant macrofossils, leaves and other vegetative and reproductive structures, at this locality. Consequently, reconstructions of the standing vegetation at Cottage Grove from these sediments lack the complementary information and a more regional perspective that can be provided by sporomorphs (prepollen, pollen, megaspores and spores). In order to provide this, we have analysed the composition of fossil sporomorph assemblages in two rock samples taken from macrofossil-bearing inter-coal shale at Cottage Grove. Our palynological data differ considerably in composition and in the dominance-diversity profile from the macrofossil vegetation at this locality. Walchian conifers and pteridosperms are common elements in the macroflora, but are absent in the sporomorph assemblages. Reversely, the sporomorph assemblages at Cottage Grove comprise 17 spore taxa (∼16% and ∼63% of the total assemblages) that are known from the lycopsid orders Isoetales, Lepidodendrales and Selaginallales, while Cottage Grove’s macrofloral record fails to capture evidence of a considerable population of coal forest lycopsids. We interpret our results as evidence that the Pennsylvanian dryland glacial landscape at Cottage Grove included fragmented populations of wetland plants living in refugia. PMID:25392752

  16. Impact of lowland forests in England on water resources: Application of the Hydrological Land Use Change (HYLUC) model

    NASA Astrophysics Data System (ADS)

    Calder, Ian R.; Reid, Ian; Nisbet, Thomas R.; Green, Julian C.

    2003-11-01

    The U.K. Government's 1995 White Paper on Rural England [, 1995] proposed a doubling of the area of woodland within England by the year 2045. Questions were later raised concerning the possible impacts on water resources of such a large change in land use. This paper presents results of field study investigations of the water use of grass, heath, oak, and pine vegetation at Clipstone Forest, Nottinghamshire, United Kingdom, which were used to calibrate the water use model HYLUC and derive predictions of the impact of different vegetation types on recharge in this locality. Average annual recharge plus runoff (millimeters) over a 32.5 year period and the uncertainties due to spatial sampling, calculated with the HYLUC model, were 136 ± 11 for the grass site, 122 ± 3 for the heath site, 76 ± 5 for the oak site, and 34 ± 8 and 38 ± 3 for two pine sites. In this region of Britain the long-term recharge beneath pine is approximately one quarter that under grass and essentially only occurs in years of above average rainfall. Oak woodland is also predicted to have a significant impact by reducing recharge plus runoff by almost one half as compared with grassland.

  17. Interception and attenuation of atmospheric pollution in a lowland ash forested site, Old Pond Close, Northamptonshire, UK.

    PubMed

    Neal, Colin

    2002-01-23

    A study of interception of chemicals at an ash plantation forest in southern-central England shows the modification of acidic pollution as it passes from precipitation, through the vegetation cover and the soil to generate surface runoff. Precipitation is highly acidic (pH 3.7-4.8, alkalinity -16 to -200 microEq/l) and it is enriched in the strong acid anions associated with acidification (sulfate and nitrate) as well as ammonium and the trace elements aluminium and zinc. The concentration of both sea-salt and pollutant components varies considerably over time and this is linked to washout from the atmosphere during precipitation events as marked by an inverse relationship between concentration and volume of catch. The catchment is also supplied by sea-salt and pollutant additions as dry deposition: gaseous inputs of SO(x) may also increase sulfate deposition. Through the vegetation, much of the acidity is neutralised and, particularly during the growth period, calcium, magnesium and potassium is cycled, while sodium and nitrate are partially removed. Within the catchment, weathering ensures that further base cation production occurs leading to enhanced neutralisation of acidity and the generation of positive alkalinities. As a result, surface runoff becomes buffered with alkalinity approximately 490 microEq/l and pH approximately 7.9. Thus, although the acidification input from the atmosphere is high, this does not translate to acidic runoff due to within-canopy and within-soil processes.

  18. Rebuilding after collapse: evidence for long-term cohort dynamics in the native Hawaiian rain forest

    USGS Publications Warehouse

    Boehmer, Hans Juergen; Wagner, Helene H.; Jacobi, James D.; Gerrish, Grant C.; Mueller-Dombois, Dieter

    2013-01-01

    Questions: Do long-term observations in permanent plots confirm the conceptual model of Metrosideros polymorpha cohort dynamics as postulated in 1987? Do regeneration patterns occur independently of substrate age, i.e. of direct volcanic disturbance impact? Location: The windward mountain slopes of the younger Mauna Loa and the older Mauna Kea volcanoes (island of Hawaii, USA). Methods: After widespread forest decline (dieback), permanent plots were established in 1976 in 13 dieback and 13 non-dieback patches to monitor the population structure of M. polymorpha at ca. 5-yr intervals. Within each plot of 20 × 20 m, all trees with DBH >2.5 cm were individually tagged, measured and tree vigour assessed; regeneration was quantified in 16 systematically placed subplots of 3 × 5 m. Data collected in the subplots included the total number of M. polymorpha seedlings and saplings (five stem height classes). Here we analyse monitoring data from six time steps from 1976 to 2003 using repeated measures ANOVA to test specific predictions derived from the 1987 conceptual model. Results: Regeneration was significantly different between dieback and non-dieback plots. In dieback plots, the collapse in the 1970s was followed by a ‘sapling wave’ that by 2003 led to new cohort stands of M. polymorpha. In non-dieback stands, seedling emergence did not result in sapling waves over the same period. Instead, a ‘sapling gap’ (i.e. very few or no M. polymorpha saplings) prevailed as typical for mature stands. Canopy dieback in 1976, degree of recovery by 2003 and the number of living trees in 2003 were unrelated to substrate age. Conclusions: Population development of M. polymorpha supports the cohort dynamics model, which predicts rebuilding of the forest with the same canopy species after dieback. The lack of association with substrate age suggests that the long-term maintenance of cohort structure in M. polymorpha does not depend on volcanic disturbance but may be related to

  19. Canopy structure of tropical and sub-tropical rain forests in relation to conifer dominance analysed with a portable LIDAR system

    PubMed Central

    Aiba, Shin-ichiro; Akutsu, Kosuke; Onoda, Yusuke

    2013-01-01

    Background and Aims Globally, conifer dominance is restricted to nutient-poor habitats in colder, drier or waterlogged environments, probably due to competition with angiosperms. Analysis of canopy structure is important for understanding the mechanism of plant coexistence in relation to competition for light. Most conifers are shade intolerant, and often have narrow, deep, conical crowns. In this study it is predicted that conifer-admixed forests have less distinct upper canopies and more undulating canopy surfaces than angiosperm-dominated forests. Methods By using a ground-based, portable light detection and ranging (LIDAR) system, canopy structure was quantified for old-growth evergreen rainforests with varying dominance of conifers along altitudinal gradients (200–3100 m a.s.l.) on tropical and sub-tropical mountains (Mount Kinabalu, Malaysian Borneo and Yakushima Island, Japan) that have different conifer floras. Key Results Conifers dominated at higher elevations on both mountains (Podocarpaceae and Araucariaceae on Kinabalu and Cupressaceae and Pinaceae on Yakushima), but conifer dominance also varied with soil/substrate conditions on Kinabalu. Conifer dominance was associated with the existence of large-diameter conifers. Forests with higher conifer dominance showed a canopy height profile (CHP) more skewed towards the understorey on both Kinabalu and Yakushima. In contrast, angiosperm-dominated forests had a CHP skewed towards upper canopy, except for lowland dipterocarp forests and a sub-alpine scrub dominated by small-leaved Leptospermum recurvum (Myrtaceae) on Kinabalu. Forests with a less dense upper canopy had more undulating outer canopy surfaces. Mixed conifer–angiosperm forests on Yakushima and dipterocarp forests on Kinabalu showed similar canopy structures. Conclusions The results generally supported the prediction, suggesting that lower growth of angiosperm trees (except L. recurvum on Kinabalu) in cold and nutrient-poor environments

  20. Converging migration routes of Eurasian hobbies Falco subbuteo crossing the African equatorial rain forest.

    PubMed

    Strandberg, Roine; Klaassen, Raymond H G; Hake, Mikael; Olofsson, Patrik; Alerstam, Thomas

    2009-02-22

    Autumn migration of adult Eurasian hobbies Falco subbuteo from Europe to southern Africa was recorded by satellite telemetry and observed routes were compared with randomly simulated routes. Two non-random features of observed routes were revealed: (i) shifts to more westerly longitudes than straight paths to destinations and (ii) strong route convergence towards a restricted area close to the equator (1 degree S, 15 degrees E). The birds migrated south or southwest to approximately 10 degrees N, where they changed to south-easterly courses. The maximal spread between routes at 10 degrees N (2134 km) rapidly decreased to a minimum (67 km) close to the equator. We found a striking relationship between the route convergence and the distribution of continuous rainforest, suggesting that hobbies minimize flight distance across the forest, concentrating in a corridor where habitat may be more suitable for travelling and foraging. With rainforest forming a possible ecological barrier, many migrants may cross the equator either at 15 degrees E, similar to the hobbies, or at 30-40 degrees E, east of the rainforest where large-scale migration is well documented. Much remains to be understood about the role of the rainforest for the evolution and future of the trans-equatorial Palaearctic-African bird migration systems.

  1. Airborne and spaceborne radar images for geologic and environmental mapping in the Amazon rain forest, Brazil

    NASA Technical Reports Server (NTRS)

    Ford, John P.; Hurtak, James J.

    1986-01-01

    Spaceborne and airborne radar image of portions of the Middle and Upper Amazon basin in the state of Amazonas and the Territory of Roraima are compared for purposes of geological and environmental mapping. The contrasted illumination geometries and imaging parameters are related to terrain slope and surface roughness characteristics for corresponding areas that were covered by each of the radar imaging systems. Landforms range from deeply dissected mountain and plateau with relief up to 500 m in Roraima, revealing ancient layered rocks through folded residual mountains to deeply beveled pediplain in Amazonas. Geomorphic features provide distinct textural signatures that are characteristic of different rock associations. The principle drainages in the areas covered are the Rio Negro, Rio Branco, and the Rio Japura. Shadowing effects and low radar sensitivity to subtle linear fractures that are aligned parallel or nearly parallel to the direction of radar illumination illustrate the need to obtain multiple coverage with viewing directions about 90 degrees. Perception of standing water and alluvial forest in floodplains varies with incident angle and with season. Multitemporal data sets acquired over periods of years provide an ideal method of monitoring environmental changes.

  2. Acclimation of seedlings of Gnetum leyboldii Tul. (Gnetaceae) to light changes in a tropical rain forest.

    PubMed

    Celis, Gerardo; Avalos, Gerardo

    2013-12-01

    The neotropical liana Gnetum leyboldii (Gnetaceae) is a gymnosperm that resembles angiosperms in wood anatomy, overall morphology, and seed dispersal mechanism. Like other woody lianas, seedlings germinate in the shaded forest understory and start climbing towards the canopy, being exposed to sites with extreme differences in light conditions. However, the extent of physiological and structural adjustment to contrasting light conditions in the early regeneration stages of Gnetum is unknown. To answer this question, we analyzed seedling growth and photosynthetic responses using a common garden experiment with two light regimes: full sun and low light (20% of full sun) at La Selva Biological Station, Costa Rica. We also characterized the germination pattern of this species. We monitored one and half-month old seedlings for four months. Leaf structure finely adapted to light treatments, but gas exchange properties were buffered by large seed reserves, which dominated biomass distribution (about 50% of the total biomass), followed by stem (27%), leaf (16%) and root biomass (6%) across light conditions. The presence of large seeds and the low photosynthetic rates of seedlings in both environments show that G. leyboldii is specialized to exploit deep shade. More research is needed to determine if the patterns found in G. leyboldii are typical of similar lianas that initially exploit deep-shaded understories in their accession to the canopy. PMID:24432539

  3. Seasonal variation in the feeding behavior and diet of Japanese macaques (Macaca fuscata yakui) in lowland forest of Yakushima.

    PubMed

    Hill, D A

    1997-01-01

    The feeding behavior of the southern subspecies of Japanese macaque (Macaca fuscata yakui) was studied over a period of 18 months in warm temperate broad-leaved forest on the island of Yakushima, Japan. Focal animal data were collected for the eight adults in the troop. Over a full annual cycle, 35.0% of foraging on identified foods was on leaves and shoots, 30.2% on fleshy fruit, 13.2% on seeds, and 5.5% on flowers. Invertebrates and other animal matter accounted for 10.3% of foraging and fungi for 4.6%. There was marked seasonal variation in the use of different food categories, and seeds, leaves, fleshy fruit, and animal matter were each predominant at different times of year. There was also evidence of annual cyclicity in patterns of foraging on all major food types. The monkeys spent less time moving and ate a greater variety of foods when feeding on leaves than when feeding on fruit and seeds, or on insects. Time spent foraging was positively correlated with diversity of the diet, but there was no simple relationship between time spent foraging and the predominant food type. This suggests that a wide variety of foods takes longer to harvest and process, irrespective of the food type. The diet of the study troop was flexible and could not be assigned to a simple dietary category, such as frugivorous or folivorous. If these data are representative of the subspecies, the Yakushima macaque is much more of a dietary generalist than most primates for which there are adequate data.

  4. Spatial scale and sampling resolution affect measures of gap disturbance in a lowland tropical forest: implications for understanding forest regeneration and carbon storage.

    PubMed

    Lobo, Elena; Dalling, James W

    2014-03-01

    Treefall gaps play an important role in tropical forest dynamics and in determining above-ground biomass (AGB). However, our understanding of gap disturbance regimes is largely based either on surveys of forest plots that are small relative to spatial variation in gap disturbance, or on satellite imagery, which cannot accurately detect small gaps. We used high-resolution light detection and ranging data from a 1500 ha forest in Panama to: (i) determine how gap disturbance parameters are influenced by study area size, and the criteria used to define gaps; and (ii) to evaluate how accurately previous ground-based canopy height sampling can determine the size and location of gaps. We found that plot-scale disturbance parameters frequently differed significantly from those measured at the landscape-level, and that canopy height thresholds used to define gaps strongly influenced the gap-size distribution, an important metric influencing AGB. Furthermore, simulated ground surveys of canopy height frequently misrepresented the true location of gaps, which may affect conclusions about how relatively small canopy gaps affect successional processes and contribute to the maintenance of diversity. Across site comparisons need to consider how gap definition, scale and spatial resolution affect characterizations of gap disturbance, and its inferred importance for carbon storage and community composition. PMID:24452032

  5. Spatial scale and sampling resolution affect measures of gap disturbance in a lowland tropical forest: implications for understanding forest regeneration and carbon storage.

    PubMed

    Lobo, Elena; Dalling, James W

    2014-03-01

    Treefall gaps play an important role in tropical forest dynamics and in determining above-ground biomass (AGB). However, our understanding of gap disturbance regimes is largely based either on surveys of forest plots that are small relative to spatial variation in gap disturbance, or on satellite imagery, which cannot accurately detect small gaps. We used high-resolution light detection and ranging data from a 1500 ha forest in Panama to: (i) determine how gap disturbance parameters are influenced by study area size, and the criteria used to define gaps; and (ii) to evaluate how accurately previous ground-based canopy height sampling can determine the size and location of gaps. We found that plot-scale disturbance parameters frequently differed significantly from those measured at the landscape-level, and that canopy height thresholds used to define gaps strongly influenced the gap-size distribution, an important metric influencing AGB. Furthermore, simulated ground surveys of canopy height frequently misrepresented the true location of gaps, which may affect conclusions about how relatively small canopy gaps affect successional processes and contribute to the maintenance of diversity. Across site comparisons need to consider how gap definition, scale and spatial resolution affect characterizations of gap disturbance, and its inferred importance for carbon storage and community composition.

  6. Variation in pH optima of hydrolytic enzyme activities in tropical rain forest soils.

    PubMed

    Turner, Benjamin L

    2010-10-01

    Extracellular enzymes synthesized by soil microbes play a central role in the biogeochemical cycling of nutrients in the environment. The pH optima of eight hydrolytic enzymes involved in the cycles of carbon, nitrogen, phosphorus, and sulfur, were assessed in a series of tropical forest soils of contrasting pH values from the Republic of Panama. Assays were conducted using 4-methylumbelliferone-linked fluorogenic substrates in modified universal buffer. Optimum pH values differed markedly among enzymes and soils. Enzymes were grouped into three classes based on their pH optima: (i) enzymes with acidic pH optima that were consistent among soils (cellobiohydrolase, β-xylanase, and arylsulfatase), (ii) enzymes with acidic pH optima that varied systematically with soil pH, with the most acidic pH optima in the most acidic soils (α-glucosidase, β-glucosidase, and N-acetyl-β-glucosaminidase), and (iii) enzymes with an optimum pH in either the acid range or the alkaline range depending on soil pH (phosphomonoesterase and phosphodiesterase). The optimum pH values of phosphomonoesterase were consistent among soils, being 4 to 5 for acid phosphomonoesterase and 10 to 11 for alkaline phosphomonoesterase. In contrast, the optimum pH for phosphodiesterase activity varied systematically with soil pH, with the most acidic pH optima (3.0) in the most acidic soils and the most alkaline pH optima (pH 10) in near-neutral soils. Arylsulfatase activity had a very acidic optimum pH in all soils (pH ≤3.0) irrespective of soil pH. The differences in pH optima may be linked to the origins of the enzymes and/or the degree of stabilization on solid surfaces. The results have important implications for the interpretation of hydrolytic enzyme assays using fluorogenic substrates.

  7. Variation in pH Optima of Hydrolytic Enzyme Activities in Tropical Rain Forest Soils ▿

    PubMed Central

    Turner, Benjamin L.

    2010-01-01

    Extracellular enzymes synthesized by soil microbes play a central role in the biogeochemical cycling of nutrients in the environment. The pH optima of eight hydrolytic enzymes involved in the cycles of carbon, nitrogen, phosphorus, and sulfur, were assessed in a series of tropical forest soils of contrasting pH values from the Republic of Panama. Assays were conducted using 4-methylumbelliferone-linked fluorogenic substrates in modified universal buffer. Optimum pH values differed markedly among enzymes and soils. Enzymes were grouped into three classes based on their pH optima: (i) enzymes with acidic pH optima that were consistent among soils (cellobiohydrolase, β-xylanase, and arylsulfatase), (ii) enzymes with acidic pH optima that varied systematically with soil pH, with the most acidic pH optima in the most acidic soils (α-glucosidase, β-glucosidase, and N-acetyl-β-glucosaminidase), and (iii) enzymes with an optimum pH in either the acid range or the alkaline range depending on soil pH (phosphomonoesterase and phosphodiesterase). The optimum pH values of phosphomonoesterase were consistent among soils, being 4 to 5 for acid phosphomonoesterase and 10 to 11 for alkaline phosphomonoesterase. In contrast, the optimum pH for phosphodiesterase activity varied systematically with soil pH, with the most acidic pH optima (3.0) in the most acidic soils and the most alkaline pH optima (pH 10) in near-neutral soils. Arylsulfatase activity had a very acidic optimum pH in all soils (pH ≤3.0) irrespective of soil pH. The differences in pH optima may be linked to the origins of the enzymes and/or the degree of stabilization on solid surfaces. The results have important implications for the interpretation of hydrolytic enzyme assays using fluorogenic substrates. PMID:20709838

  8. Spatial analysis of charcoal kiln remains in the former royal forest district Tauer (Lower Lusatia, North German Lowlands)

    NASA Astrophysics Data System (ADS)

    Raab, Alexandra; Schneider, Anna; Bonhage, Alexander; Takla, Melanie; Hirsch, Florian; Müller, Frank; Rösler, Horst; Heußner, Karl-Uwe

    2016-04-01

    Archaeological excavations have revealed more than thousand charcoal kiln remains (CKRs) in the prefield of the active opencast lignite mine Jänschwalde, situated about 150 km SE of Berlin (SE Brandenburg, Germany). The charcoal was mainly produced for the ironwork Peitz nearby, which operated from the 16th to the mid-19th centuries. In a first approach, to estimate the dimension of the charcoal production, CKRs were mapped on shaded-relief maps (SRMs) derived from high-resolution LiDAR data (Raab et al. 2015). Subsequently, for a selected test area, identified CKRs on the SRMs were compared with archaeologically excavated CKRs in the field. This survey showed a considerably number of falsely detected sites. Therefore, the data was critically re-evaluated using additional relief visualisations. Further, we extended the CKR mapping to areas which are not archaeologically investigated. The study area, the former royal forest district Tauer, consists of two separate areas: the Tauersche Heide (c. 96 km2 area) N of Peitz and the area Jänschwalde (c. 32 km2 area) NE of Peitz. The study area is characterized by a flat topography. Different former and current anthropogenic uses (e.g., military training, solar power plant, forestry measures) have affected the study area, resulting in extensive disturbances of the terrain surface. The revised CKR abundance in the study area Jänschwalde was considerably smaller than the numbers produced by our first approach. Further, the CKR mapping revealed, that a total record of the CKRs is not possible for various reasons. Despite these limitations, a solid database can be provided for a much larger area than before. Basic statistic parameters of the CKR diameters and all comparative statistical tests were calculated using SPSS. To detect underlying spatial relationships in the CKR site distribution, we applied the Getis-Ord Gi* statistic, a method to test for local spatial autocorrelation between neighbouring sites. The test is

  9. Functional trait trade-offs for the tropical montane rain forest species responding to light from simulating experiments.

    PubMed

    Mao, Peili; Zang, Runguo; Shao, Hongbo; Yu, Junbao

    2014-01-01

    Differences among tropical tree species in survival and growth to light play a key role in plant competition and community composition. Two canopy species with contrasting functional traits dominating early and late successional stages, respectively, in a tropical montane rain forest of Hainan Island, China, were selected in a pot experiment under 4 levels of light intensity (full, 50%, 30%, and 10%) in order to explore the adaptive strategies of tropical trees to light conditions. Under each light intensity level, the pioneer species, Endospermum chinense (Euphorbiaceae), had higher relative growth rate (RGR), stem mass ratio (SMR), specific leaf area (SLA), and morphological plasticity while the shade tolerant climax species, Parakmeria lotungensis (Magnoliaceae), had higher root mass ratio (RMR) and leaf mass ratio (LMR). RGR of both species was positively related to SMR and SLA under each light level but was negatively correlated with RMR under lower light (30% and 10% full light). The climax species increased its survival by a conservative resource use strategy through increasing leaf defense and root biomass investment at the expense of growth rate in low light. In contrast, the pioneer increased its growth by an exploitative resource use strategy through increasing leaf photosynthetic capacity and stem biomass investment at the expense of survival under low light. There was a trade-off between growth and survival for species under different light conditions. Our study suggests that tree species in the tropical rainforest adopt different strategies in stands of different successional stages. Species in the earlier successional stages have functional traits more advantageous to grow faster in the high light conditions, whereas species in the late successional stages have traits more favorable to survive in the low light conditions.

  10. Functional Trait Trade-Offs for the Tropical Montane Rain Forest Species Responding to Light from Simulating Experiments

    PubMed Central

    Mao, Peili; Zang, Runguo; Shao, Hongbo; Yu, Junbao

    2014-01-01

    Differences among tropical tree species in survival and growth to light play a key role in plant competition and community composition. Two canopy species with contrasting functional traits dominating early and late successional stages, respectively, in a tropical montane rain forest of Hainan Island, China, were selected in a pot experiment under 4 levels of light intensity (full, 50%, 30%, and 10%) in order to explore the adaptive strategies of tropical trees to light conditions. Under each light intensity level, the pioneer species, Endospermum chinense (Euphorbiaceae), had higher relative growth rate (RGR), stem mass ratio (SMR), specific leaf area (SLA), and morphological plasticity while the shade tolerant climax species, Parakmeria lotungensis (Magnoliaceae), had higher root mass ratio (RMR) and leaf mass ratio (LMR). RGR of both species was positively related to SMR and SLA under each light level but was negatively correlated with RMR under lower light (30% and 10% full light). The climax species increased its survival by a conservative resource use strategy through increasing leaf defense and root biomass investment at the expense of growth rate in low light. In contrast, the pioneer increased its growth by an exploitative resource use strategy through increasing leaf photosynthetic capacity and stem biomass investment at the expense of survival under low light. There was a trade-off between growth and survival for species under different light conditions. Our study suggests that tree species in the tropical rainforest adopt different strategies in stands of different successional stages. Species in the earlier successional stages have functional traits more advantageous to grow faster in the high light conditions, whereas species in the late successional stages have traits more favorable to survive in the low light conditions. PMID:25019095

  11. Anti-Streptococcal activity of Brazilian Amazon Rain Forest plant extracts presents potential for preventive strategies against dental caries

    PubMed Central

    da SILVA, Juliana Paola Corrêa; de CASTILHO, Adriana Lígia; SARACENI, Cíntia Helena Couri; DÍAZ, Ingrit Elida Collantes; PACIÊNCIA, Mateus Luís Barradas; SUFFREDINI, Ivana Barbosa

    2014-01-01

    Caries is a global public health problem, whose control requires the introduction of low-cost treatments, such as strong prevention strategies, minimally invasive techniques and chemical prevention agents. Nature plays an important role as a source of new antibacterial substances that can be used in the prevention of caries, and Brazil is the richest country in terms of biodiversity. Objective In this study, the disk diffusion method (DDM) was used to screen over 2,000 Brazilian Amazon plant extracts against Streptococcus mutans. Material and Methods Seventeen active plant extracts were identified and fractionated. Extracts and their fractions, obtained by liquid-liquid partition, were tested in the DDM assay and in the microdilution broth assay (MBA) to determine their minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs). The extracts were also subjected to antioxidant analysis by thin layer chromatography. Results EB271, obtained from Casearia spruceana, showed significant activity against the bacterium in the DDM assay (20.67±0.52 mm), as did EB1129, obtained from Psychotria sp. (Rubiaceae) (15.04±2.29 mm). EB1493, obtained from Ipomoea alba, was the only extract to show strong activity against Streptococcus mutans (0.08 mg/mLrain forest, show potential as sources of new antibacterial agents for use as chemical coadjuvants in prevention strategies to treat caries. PMID:24676578

  12. Seasonal patterns of leaf gas exchange and water relations in dry rain forest trees of contrasting leaf phenology.

    PubMed

    Choat, Brendan; Ball, Marilyn C; Luly, Jon G; Donnelly, Christine F; Holtum, Joseph A M

    2006-05-01

    Diurnal and seasonal patterns of leaf gas exchange and water relations were examined in tree species of contrasting leaf phenology growing in a seasonally dry tropical rain forest in north-eastern Australia. Two drought-deciduous species, Brachychiton australis (Schott and Endl.) A. Terracc. and Cochlospermum gillivraei Benth., and two evergreen species, Alphitonia excelsa (Fenzal) Benth. and Austromyrtus bidwillii (Benth.) Burret. were studied. The deciduous species had higher specific leaf areas and maximum photosynthetic rates per leaf dry mass in the wet season than the evergreens. During the transition from wet season to dry season, total canopy area was reduced by 70-90% in the deciduous species and stomatal conductance (g(s)) and assimilation rate (A) were markedly lower in the remaining leaves. Deciduous species maintained daytime leaf water potentials (Psi(L)) at close to or above wet season values by a combination of stomatal regulation and reduction in leaf area. Thus, the timing of leaf drop in deciduous species was not associated with large negative values of daytime Psi(L) (greater than -1.6 MPa) or predawn Psi(L) (greater than -1.0 MPa). The deciduous species appeared sensitive to small perturbations in soil and leaf water status that signalled the onset of drought. The evergreen species were less sensitive to the onset of drought and g(s) values were not significantly lower during the transitional period. In the dry season, the evergreen species maintained their canopies despite increasing water-stress; however, unlike Eucalyptus species from northern Australian savannas, A and g(s) were significantly lower than wet season values. PMID:16452079

  13. Seasonal patterns of leaf gas exchange and water relations in dry rain forest trees of contrasting leaf phenology.

    PubMed

    Choat, Brendan; Ball, Marilyn C; Luly, Jon G; Donnelly, Christine F; Holtum, Joseph A M

    2006-05-01

    Diurnal and seasonal patterns of leaf gas exchange and water relations were examined in tree species of contrasting leaf phenology growing in a seasonally dry tropical rain forest in north-eastern Australia. Two drought-deciduous species, Brachychiton australis (Schott and Endl.) A. Terracc. and Cochlospermum gillivraei Benth., and two evergreen species, Alphitonia excelsa (Fenzal) Benth. and Austromyrtus bidwillii (Benth.) Burret. were studied. The deciduous species had higher specific leaf areas and maximum photosynthetic rates per leaf dry mass in the wet season than the evergreens. During the transition from wet season to dry season, total canopy area was reduced by 70-90% in the deciduous species and stomatal conductance (g(s)) and assimilation rate (A) were markedly lower in the remaining leaves. Deciduous species maintained daytime leaf water potentials (Psi(L)) at close to or above wet season values by a combination of stomatal regulation and reduction in leaf area. Thus, the timing of leaf drop in deciduous species was not associated with large negative values of daytime Psi(L) (greater than -1.6 MPa) or predawn Psi(L) (greater than -1.0 MPa). The deciduous species appeared sensitive to small perturbations in soil and leaf water status that signalled the onset of drought. The evergreen species were less sensitive to the onset of drought and g(s) values were not significantly lower during the transitional period. In the dry season, the evergreen species maintained their canopies despite increasing water-stress; however, unlike Eucalyptus species from northern Australian savannas, A and g(s) were significantly lower than wet season values.

  14. Description of FORICO: a tropical gap dynamics model of the lower montane rain forest of Puerto Rico. Environmental Sciences Division Publication No. 1875

    SciTech Connect

    Doyle, T.W.

    1982-09-01

    The FORICO model, a gap dynamics model of the lower montane rain forest in Puerto Rico, is documented. It simulates gap formation and replacement of a 1/30 ha forest stand. The model increments the growth of individual trees, introduces new seedlings, and considers the death of trees on a per annum basis. This stochastic gap model also simulates the return frequency and stand damage effects of hurricanes common to West Indian forests. Key autecological parameters of 36 common tree species are used as input to the model. Model subroutines are illustrated and described in their order and function. A listing of the FORICO model and a sample of model output is included.

  15. Acid rain: Reign of controversy

    SciTech Connect

    Kahan, A.M.

    1986-01-01

    Acid Rain is a primer on the science and politics of acid rain. Several introductory chapters describe in simple terms the relevant principles of water chemistry, soil chemistry, and plant physiology and discuss the demonstrated or postulated effects of acid rain on fresh waters and forests as well as on statuary and other exposed objects. There follow discussions on the economic and social implications of acid rain (for example, possible health effects) and on the sources, transport, and distribution of air pollutants.

  16. New methodology for quantifying the relative impacts on hydrological ecosystem services of tropical rain forest disturbance for long-term timber production or oil palm production

    NASA Astrophysics Data System (ADS)

    Chappell, N. A.; Sinun, W.

    2010-12-01

    The principal aim of our new methodology is a demonstration of the hydrological or water resources value of disturbed natural forest (e.g., selectively-harvested rain forest) versus other land uses, e.g., oil palm plantation. The first stage of the methodology is to list well-defined, hydrological attributes that characterise the response of experimental catchments in the humid tropics (e.g., flood peak, Q95 low-flows, suspended sediment load, pesticide load). Each hydrological attribute (i.e., ‘hydrological ecosystem service’) is defined by state-of-the-art understanding of tropical hydrological processes. Secondly, to quantify the difference between the responses of catchments covered by undisturbed natural forest and those covered by disturbed natural forest and introduced covers (e.g., oil palm plantation, vegetable farming). These are values of absolute and relative change (from field research, not simply classes of +/- change), specific to the year post change introduction. Lastly, the potential economic cost (+/-) of returning each hydrological attribute back to those states seen in undisturbed (and distributed) natural forest is then quantified, and all costs summed. These figures specific to the year post change introduction (i.e., 1-year and 20-years), can be used to compare the overall hydrological impact (on community and state economics) of different land cover changes. The methodology is implemented within the new esHYDRO model running under Matlab®, using research data from the chosen case study area and elsewhere. The case study area is within Sabah, Malaysian Borneo, and the two changes being illustrated at 1- and 20-years post introduction are the hydrological service impacts resulting from a change to either selectively-harvested rain forest or oil palm plantation. Uncertainties are quantified throughout, and principal uncertainties highlighted.

  17. Reliable rain rates from optical satellite sensors - a random forests-based approach for the hourly retrieval of rainfall rates from Meteosat SEVIRI

    NASA Astrophysics Data System (ADS)

    Kühnlein, Meike; Appelhans, Tim; Thies, Boris; Nauss, Thomas

    2013-04-01

    Many ecological and biodiversity-oriented projects require area-wide precipitation information and satellite-based rainfall retrievals are often the only option. Using optical and microphysical cloud property retrievals, area-wide information about the distribution of precipitating clouds can generally be provided from optical sensors aboard geostationary (GEO) weather satellites. However, the retrieval of spatio-temporal high resolution rainfall amounts from such sensors bears large uncertainties. In existing optical retrievals, the rainfall rate is generally retrieved as a function of the cloud-top temperature which leads to sufficient results for deep-convective systems but such a concept is inappropriate for any kind of advective/stratiform precipitation formation processes. To overcome this drawback, several authors suggest to use optical and microphysical cloud parameters not only for the rain-area delineation but also for the rain rate retrieval. In the present study, a method has been developed to estimate hourly rainfall rates using cloud physical properties retrieved from MSG SEVIRI data. The rainfall rate assignment is realized by using an ensemble classification and regression technique, called random forests. This method is already widely established in other disciplines, but has not yet been utilized extensively by climatologists. Random forests is used to assign rainfall rates to already identified rain areas in a two-step approach. First, the rain area is separated into areas of precipitation processes. Next, rainfall rates are assigned to these areas. For the development and validation of the new technique, radar-based precipitation data of the German Weather Service is used. The so-called RADOLAN RW product provide gauge-adjusted hourly precipitation amounts at a temporal resolution of one hour. Germany is chosen as the study area of the new technique. The region can be regarded as sufficiently representative for mid-latitudes precipitation

  18. Ranking the Rain Forests.

    ERIC Educational Resources Information Center

    Roberts, Leslie

    1991-01-01

    Described is the Rapid Assessment Program (RAP) in which a team of tropical biologists are able to get to remote, uncharted sites in the tropics and conduct surveys very quickly. The team uses satellite imagery, aerial reconnaissance, and field surveys to produce an inventory of species found in these areas. (KR)

  19. Researching the Rain Forest.

    ERIC Educational Resources Information Center

    Chazdon, Robin L.

    1995-01-01

    An autobiography of a female ecologist working in the Costa Rican rainforest is provided as an inspiration for girls. The scientist briefly tells her life story and describes her research activities. (LZ)

  20. Effects of simulated acid rain on soil respiration and its components in a subtropical mixed conifer and broadleaf forest in southern China.

    PubMed

    Liang, Guohua; Hui, Dafeng; Wu, Xiaoying; Wu, Jianping; Liu, Juxiu; Zhou, Guoyi; Zhang, Deqiang

    2016-02-01

    Soil respiration is a major pathway in the global carbon cycle and its response to environmental changes is an increasing concern. Here we explored how total soil respiration (RT) and its components respond to elevated acid rain in a mixed conifer and broadleaf forest, one of the major forest types in southern China. RT was measured twice a month in the first year under four treatment levels of simulated acid rain (SAR: CK, the local lake water, pH 4.7; T1, water pH 4.0; T2, water pH 3.25; and T3, water pH 2.5), and in the second year, RT, litter-free soil respiration (RS), and litter respiration (RL) were measured simultaneously. The results indicated that the mean rate of RT was 2.84 ± 0.20 μmol CO2 m(-2) s(-1) in the CK plots, and RS and RL contributed 60.7% and 39.3% to RT, respectively. SAR marginally reduced (P = 0.08) RT in the first year, but significantly reduced RT and its two components in the second year (P < 0.05). The negative effects were correlated with the decrease in soil microbial biomass and fine root biomass due to soil acidification under the SAR. The temperature coefficients (Q10) of RT and its two components generally decreased with increasing levels of the SAR, but only the decrease of RT and RL was significant (P < 0.05). In addition, the contribution of RL to RT decreased significantly under the SAR, indicating that RL was more sensitive to the SAR than RS. In the context of elevated acid rain, the decline trend of RT in the forests in southern China appears to be attributable to the decline of soil respiration in the litter layer. PMID:26755128

  1. Effects of simulated acid rain on soil respiration and its components in a subtropical mixed conifer and broadleaf forest in southern China.

    PubMed

    Liang, Guohua; Hui, Dafeng; Wu, Xiaoying; Wu, Jianping; Liu, Juxiu; Zhou, Guoyi; Zhang, Deqiang

    2016-02-01

    Soil respiration is a major pathway in the global carbon cycle and its response to environmental changes is an increasing concern. Here we explored how total soil respiration (RT) and its components respond to elevated acid rain in a mixed conifer and broadleaf forest, one of the major forest types in southern China. RT was measured twice a month in the first year under four treatment levels of simulated acid rain (SAR: CK, the local lake water, pH 4.7; T1, water pH 4.0; T2, water pH 3.25; and T3, water pH 2.5), and in the second year, RT, litter-free soil respiration (RS), and litter respiration (RL) were measured simultaneously. The results indicated that the mean rate of RT was 2.84 ± 0.20 μmol CO2 m(-2) s(-1) in the CK plots, and RS and RL contributed 60.7% and 39.3% to RT, respectively. SAR marginally reduced (P = 0.08) RT in the first year, but significantly reduced RT and its two components in the second year (P < 0.05). The negative effects were correlated with the decrease in soil microbial biomass and fine root biomass due to soil acidification under the SAR. The temperature coefficients (Q10) of RT and its two components generally decreased with increasing levels of the SAR, but only the decrease of RT and RL was significant (P < 0.05). In addition, the contribution of RL to RT decreased significantly under the SAR, indicating that RL was more sensitive to the SAR than RS. In the context of elevated acid rain, the decline trend of RT in the forests in southern China appears to be attributable to the decline of soil respiration in the litter layer.

  2. One-year delayed effect of fog on malaria transmission: a time-series analysis in the rain forest area of Mengla County, south-west China

    PubMed Central

    Tian, Linwei; Bi, Yan; Ho, Suzanne C; Liu, Wenjie; Liang, Song; Goggins, William B; Chan, Emily YY; Zhou, Shuisen; Sung, Joseph JY

    2008-01-01

    Background Malaria is a major public health burden in the tropics with the potential to significantly increase in response to climate change. Analyses of data from the recent past can elucidate how short-term variations in weather factors affect malaria transmission. This study explored the impact of climate variability on the transmission of malaria in the tropical rain forest area of Mengla County, south-west China. Methods Ecological time-series analysis was performed on data collected between 1971 and 1999. Auto-regressive integrated moving average (ARIMA) models were used to evaluate the relationship between weather factors and malaria incidence. Results At the time scale of months, the predictors for malaria incidence included: minimum temperature, maximum temperature, and fog day frequency. The effect of minimum temperature on malaria incidence was greater in the cool months than in the hot months. The fog day frequency in October had a positive effect on malaria incidence in May of the following year. At the time scale of years, the annual fog day frequency was the only weather predictor of the annual incidence of malaria. Conclusion Fog day frequency was for the first time found to be a predictor of malaria incidence in a rain forest area. The one-year delayed effect of fog on malaria transmission may involve providing water input and maintaining aquatic breeding sites for mosquitoes in vulnerable times when there is little rainfall in the 6-month dry seasons. These findings should be considered in the prediction of future patterns of malaria for similar tropical rain forest areas worldwide. PMID:18565224

  3. Stable isotopes in nitrous oxide emitted from tropical rain forest soils and agricultural fields: Implications for the global atmospheric nitrous oxide budget

    NASA Astrophysics Data System (ADS)

    Perez, Tibisay Josefina

    Nitrous oxide (N2O) is an important greenhouse gas and is the primary source of NOx in the stratosphere. Large uncertainties exist in the global N2O budget, mainly due to the high uncertainty associated with source estimates. Recently, stable isotopes of 15N and 18O have been proposed as a tool to better constrain the N2O global budget. This thesis develops analytical methods for constraining and measuring stable isotopes in N2O emitted from soils and reports initial investigations of N2O isotopes from the largest sources in the global N2O budget: tropical rain forest soils and agricultural fields. We found significant differences in the isotopic composition of N 2O emitted from tropical rain forest soils and fertilized agricultural fields. Differences were largest for 15N. Emission-weighted δ 15N-N2O were -26 +/- 2.5‰ s.d., n = 3 (Costa Rican forest), -6.6 +/- 11.3‰ s.d. n = 14 (Brazilian forest) and -36.7 +/- 9.2‰ s.d. n = 19 (Mexican agricultural field and Costa Rican Papaya plantation). We attribute the large range in δ 15N from tropical rain forests, where denitrification is the main source of N2O, to differences in the degree of N2O to N2 reduction. We attribute the very light δ15N values in fertilized agricultural fields to the enhanced nitrogen availability in the soils which facilitates higher fractionation between substrates and products. Similarly, in the Brazilian tropical forest lighter δ 15N-N2O from a local area of enhanced emission is attributed to locally more abundant N- substrate in that particular soil site. If the increase of N2O in the troposphere over the past 100 years is attributable to increased use of N fertilizer, and assuming that light δ 15N- N2O isotopic values are associated with agricultural practices, we expect the δ15N-N2O in the troposphere to have decreased since pre-industrial times. Theoretically, comparison of 15N and 18O signature of emitted N2O with precursors species (NO3 -, NH4+, H2O and O 2) should uniquely

  4. Origin and global diversification patterns of tropical rain forests: inferences from a complete genus-level phylogeny of palms

    PubMed Central

    2011-01-01

    Background Understanding how biodiversity is shaped through time is a fundamental question in biology. Even though tropical rain forests (TRF) represent the most diverse terrestrial biomes on the planet, the timing, location and mechanisms of their diversification remain poorly understood. Molecular phylogenies are valuable tools for exploring these issues, but to date most studies have focused only on recent time scales, which minimises their explanatory potential. In order to provide a long-term view of TRF diversification, we constructed the first complete genus-level dated phylogeny of a largely TRF-restricted plant family with a known history dating back to the Cretaceous. Palms (Arecaceae/Palmae) are one of the most characteristic and ecologically important components of TRF worldwide, and represent a model group for the investigation of TRF evolution. Results We provide evidence that diversification of extant lineages of palms started during the mid-Cretaceous period about 100 million years ago. Ancestral biome and area reconstructions for the whole family strongly support the hypothesis that palms diversified in a TRF-like environment at northern latitudes. Finally, our results suggest that palms conform to a constant diversification model (the 'museum' model or Yule process), at least until the Neogene, with no evidence for any change in diversification rates even through the Cretaceous/Paleogene mass extinction event. Conclusions Because palms are restricted to TRF and assuming biome conservatism over time, our results suggest the presence of a TRF-like biome in the mid-Cretaceous period of Laurasia, consistent with controversial fossil evidence of the earliest TRF. Throughout its history, the TRF biome is thought to have been highly dynamic and to have fluctuated greatly in extent, but it has persisted even during climatically unfavourable periods. This may have allowed old lineages to survive and contribute to the steady accumulation of diversity over

  5. Community-wide assessment of pollen limitation in hummingbird-pollinated plants of a tropical montane rain forest

    PubMed Central

    Wolowski, Marina; Ashman, Tia-Lynn; Freitas, Leandro

    2013-01-01

    Background and Aims Although pollen limitation of reproduction (PL) has been widely studied, our understanding of its occurrence in tropical communities, especially for bird-pollinated plants, is underdeveloped. In addition, inclusion of both quantity and quality aspects in studies of PL are generally lacking. Within hummingbird-pollinated plants, a prediction was made for higher PL for the quality than quantity aspects and a minor effect of temporal variation because hummingbirds are constant and efficient pollen vectors but they may transfer low quality pollen. Methods Field hand and open pollination experiments were conducted on 21 species in a tropical montane rain forest over 2 years. The quantity (fruit set and seeds per fruit) and quality (seed weight and germination) aspects of reproduction were assessed as the response to open pollination relative to outcross hand pollination. The relationships between the effect size of quantity and quality aspects of reproduction and predictive plant features (self-incompatibility, autogamy, density and pollinator specialization level) were assessed with phylogenetic generalized linear models. Key Results Just over half of all the species expressed PL for one or more response variables. On average, the severity of PL was strong for one quality variable (seed germination; 0·83), but insignificant for another (seed weight; –0·03), and low to moderate for quantity variables (0·31 for seeds per fruit and 0·39 for fruit set). There was only a minor contribution of temporal variation to PL within the studied species. Common predictors of PL, i.e. phylogenetic relatedness, self-incompatibility, autogamy, plant density and pollinator specialization level, did not adequately explain variation in PL within this community. Conclusions Despite the measurable degree of PL within these hummingbird-pollinated plants, the causes of pollen quality and quantity insufficiency are not clear. Variables other than those tested may

  6. The emergence of modern type rain forests and mangroves and their traces in the palaeobotanical record during the Late Cretaceous and early Tertiary

    NASA Astrophysics Data System (ADS)

    Mohr, Barbara; Coiffard, Clément

    2014-05-01

    The origin of modern rain forests is still very poorly known. This ecosystem could have potentially fully evolved only after the development of relatively high numbers of flowering plant families adapted to rain forest conditions. During the early phase of angiosperm evolution in the early Cretaceous the palaeo-equatorial region was located in a seasonally dry climatic belt, so that during this phase, flowering plants often show adaptations to drought, rather than to continuously wet climate conditions. Therefore it is not surprising that except for the Nymphaeales, the most basal members of extant angiosperm families have members that do not necessarily occur in the continuously wet tropics today. However, during the late Early Cretaceous several clades emerged that later would give rise to families that are typically found today mostly in (shady) moist places in warmer regions. This is especially seen among the monocotyledons, a group of the mesangiosperms, that developed in many cases large leaves often with very specific venation patterns that make these leaves very unique and well recognizable. Especially members of three groups are here of interest: the arum family (Araceae), the palms (Arecaceae) and the Ginger and allies (Zingiberales). The earliest fossil of Araceae are restricted to low latitudes during the lower Cretaceous. Arecaceae and Zingiberales do not appear in the fossil record before the early late Cretaceous and occur at mid latitudes. During the Late Cretaceous, Araceae are represented at mid latitudes by non-tropical early diverging members and at low latitudes by derived rainforest members. Palms became widespread during the Late Cretataceous and also Nypa, a typical element of tropical to subtropical mangrove environments evolved during this time period. During the Paleocene Arecaceae appear to be restricted to lower latitudes as well as Zingiberales. All three groups are again widespread during the Eocene, reaching higher latitudes and

  7. Acid rain

    SciTech Connect

    Sweet, W.

    1980-06-20

    Acid precipitation includes not only rain but also acidified snow, hail and frost, as well as sulfur and nitrogen dust. The principal source of acid precipitation is pollution emitted by power plants and smelters. Sulfur and nitrogen compounds contained in the emissions combine with moisture to form droplets with a high acid content - sometimes as acidic as vinegar. When sufficiently concentrated, these acids can kill fish and damage material structures. Under certain circumstances they may reduce crop and forest yields and cause or aggravate respiratory diseases in humans. During the summer, especially, pollutants tend to collect over the Great Lakes in high pressure systems. Since winds typically are westerly and rotate clockwise around high pressure systems, the pollutants gradually are dispersed throughout the eastern part of the continent.

  8. After the Rain: Rain.

    ERIC Educational Resources Information Center

    Old Elk, Arlene; Stoklas, Jackie

    The Heard Museum (Phoenix, Arizona) has developed and updated an integrated curriculum for use in grades K-3. The goals for this curriculum are to: (1) share museum resources with schools; (2) promote cross-cultural understanding through a focus on rain, a universal requirement for life; (3) help students understand that Native Americans are…

  9. Seed rain, soil seed bank, seed loss and regeneration of Castanopsis fargesii (Fagaceae) in a subtropical evergreen broad-leaved forest

    USGS Publications Warehouse

    Du, X.; Guo, Q.; Gao, X.; Ma, K.

    2007-01-01

    Understanding the seed rain and seed loss dynamics in the natural condition has important significance for revealing the natural regeneration mechanisms. We conducted a 3-year field observation on seed rain, seed loss and natural regeneration of Castanopsis fargesii Franch., a dominant tree species in evergreen broad-leaved forests in Dujiangyan, southwestern China. The results showed that: (1) there were marked differences in (mature) seed production between mast (733,700 seeds in 2001) and regular (51,200 and 195,600 seeds in 2002 and 2003, respectively) years for C. fargesii. (2) Most seeds were dispersed in leaf litter, humus and 0-2 cm depth soil in seed bank. (3) Frequency distributions of both DBH and height indicated that C. fargesii had a relatively stable population. (4) Seed rain, seed ground density, seed loss, and leaf fall were highly dynamic and certain quantity of seeds were preserved on the ground for a prolonged time due to predator satiation in both the mast and regular years so that the continuous presence of seed bank and seedling recruitments in situ became possible. Both longer time observations and manipulative experiments should be carried out to better understand the roles of seed dispersal and regeneration process in the ecosystem performance. ?? 2006 Elsevier B.V. All rights reserved.

  10. The effects of ice storm on seed rain and seed limitation in an evergreen broad-leaved forest in east China

    NASA Astrophysics Data System (ADS)

    Du, Yanjun; Mi, Xiangcheng; Liu, Xiaojuan; Ma, Keping

    2012-02-01

    Extreme climatic events almost universally play a major role in influencing the composition and structure of plant and animal communities, and thus could influence seed production, seed dispersal and seedling recruitment. We explored the effects of ice storm damage on seed rain and seed limitation in a 24-ha permanent forest plot in an evergreen broad-leaved forest in east China. We compared seed production before and after the storm in 2008. We evaluated the following hypotheses: 1) seed production after the ice storm was less than that before the storm; 2) seed limitation after the storm was more severe than before the storm. The results showed that seeds from one species, Eurya muricata, dominated the seed rain after the storm, accounting for more than half of the total seeds. Post-ice storm seed production of species other than E. muricata was only one fifth of that before the storm. Seed production in the second year after the ice storm recovered to pre-storm levels. The results indicate large inter-specific variation in response to the ice storm. Disturbance caused by the ice storm greatly increased seed diversity. The Jaccard similarity of species before and after the ice storm was 58%. There was no significant difference in seed limitation or dispersal limitation before and after the storm, but there was a significant difference in source limitation. Neither seed limitation nor dispersal limitation was correlated with dispersal modes. Only source limitation for rodent dispersed species increased after the ice storm.

  11. Simulation of water available for runoff in clearcut forest openings during rain-on-snow events in the western Cascade Range of Oregon and Washington

    USGS Publications Warehouse

    van Heeswijk, Marijke; Kimball, J.S.; Marks, Danny

    1996-01-01

    Rain-on-snow events are common on mountain slopes within the transient-snow zone of the Pacific Northwest. These events make more water available for runoff than does precipitation alone by melting the snowpack and by adding a small amount of condensate to the snowpack. In forest openings (such as those resulting from clearcut logging), the amount of snow that accumulates and the turbulent- energy input to the snowpack are greater than below forest stands. Both factors are believed to contribute to a greater amount of water available for runoff during rain-on-snow events in forest openings than forest stands. Because increased water available for runoff may lead to increased downstream flooding and erosion, knowledge of the amount of snowmelt that can occur during rain on snow and the processes that control snowmelt in forest openings is useful when making land-use decisions. Snow accumulation and melt were simulated for clearcut conditions only, using an enery- balance approach that accounts for the most important energy and mass exchanges between a snowpack and its environment. Meteorological measurements provided the input for the simulations. Snow accumulation and melt were not simulated in forest stands because interception of precipitation processes are too complex to simulate with a numerical model without making simplifying assumptions. Such a model, however, would need to be extensively tested against representative observations, which were not available for this study. Snowmelt simulated during three rain-on-snow events (measured in a previous study in a clearcut in the transient-snow zone of the H.J. Andrews Experimental Forest in Oregon) demonstrated that melt generation is most sensitive to turbulent- energy exchanges between the air and the snowpack surface. As a result, the most important climate variable that controls snowmelt is wind speed. Air temperature, however, is a significant variable also. The wind speeds were light, with a maximum of 3

  12. The Ecological basis of hunter-gatherer subsistence in African Rain Forests: the Mbuti of eastern Zaire

    SciTech Connect

    Hart, T.B.; Hart, J.A.

    1986-03-01

    The Mbuti pygmies, hunter-gathers of the Ituri Forest of Zaire, trade forest products and labor for agricultural foods. It has been assumed that the Mbuti lived independently in the equatorial forest prior to its penetration by shifting cultivators. We assessed forest food resources (plant and animal) to determine their adequacy to support a hunting and gathering economy. For five months of the year, essentially none of the calorically important forest fruits and seeds are available. Honey is not abundant during this season of scarcity. Wild game meat is available year round, but the main animals caught have low fat content. This makes them a poor substitute for starch-dense agricultural foods, now staples in Mbuti diet. In general, in the closed evergreen forest zone, edible wild plant species are more abundant in agriculturally derived secondary forest than in primary forest. Similarly, they are more common at the savanna ecotone and in gallery forests. We suggest that it is unlikely that hunter-gatherers would have lived independently in the forest interior with its precarious resource base, when many of the food species they exploit are more abundant toward the savanna border.

  13. Histochemical enzyme variation in Onchocerca volvulus microfilariae from rain-forest and Sudan-savanna areas of the Onchocerciasis Control Programme in West Africa.

    PubMed

    Omar, M S; Prost, A; Marshall, T F

    1982-01-01

    Histochemical staining methods for acid phosphatase were used to study the differences among microfilariae of various West African strains of Onchocerca volvulus in both forest and Sudan-savanna onchocerciasis zones. The results have shown statistically significant differences in the staining patterns of microfilarial populations in the two zones. In the rain-forest areas, where onchocerciasis is transmitted by Simulium yahense, S. sanctipauli, S. soubrense and S. squamosum, there were no significant differences of microfilarial staining patterns in patients, by age and sex, between the three Simulium-Onchocerca complexes studied. There was a close relationship between the "strain differences", as revealed morphoenzymatically, and the clinical picture of the disease in both the forest and the Sudan-savanna zones. The present findings are in favour of the hypothesis that there are intrinsic differences in the strains of the parasite occurring in the two areas. The application of the histochemical means of parasite characterization appears to be a useful tool in differentiating strains of O. volvulus and could contribute towards a better understanding of the epidemiology of human onchocerciasis in different bioclimatic zones where the disease is endemic.

  14. Water flow pathway and the organic carbon discharge during rain storm events in a coniferous forested head watershed, Tokyo, central Japan

    NASA Astrophysics Data System (ADS)

    Moriizumi, Mihoko; Terajima, Tomomi

    2010-05-01

    The current intense discussion of the green house effect, that has been one of the main focuses on the carbon cycle in environmental systems of the earth, seems to be weakened the importance related to the effect of carbonic materials on substance movement in the aquatic environments; though it has just begun to be referred recently. Because dissolved organic carbon (DOC) in stream flows believes to play a main role of the carbon cycle in the fresh water environment, seasonal changes in DOC discharge were investigated in catchments with various scale and land use, especially in forested catchments which are one of the important sources of DOC. In order to understand the fundamental characteristics of the discharge of dissolved organic materials, stream flows, DOC, and fulvic acid like materials (FA) included in stream flows were measured in a coniferous forested head watershed. The watershed is located at the southeast edge of the Kanto mountain and is 40 km west of Tokyo with the elevation from 720 to 820 m and mean slope gradient of 38 degrees. Geology of the watershed is underlain by the sequence of mud and sand stones in Jurassic and the soil in the watershed is Cambisol (Inceptisols). The watershed composes of a dense cypress and cedar forest of 45 years old with poor understory vegetation. Observations were carried out for 6 rain storms of which the total precipitations ranged between 16.2 and 117.4 mm. The magnitude of the storms was classified into small, middle, and big events on the basis of the total precipitation of around 20, 40, and more than 70 mm. Stream flows were collected during the storm events by 1 hour interval and were passed through the 0.45 μm filters, and then the DOC concentrations in the flows were measured with a total organic carbon analyzer. The relative concentrations of fulvic acid (FA) in the flows were monitored with three dimensional excitations emission matrix fluorescence spectroscopy, because fulvic acid shows distinctive

  15. Candida riodocensis and Candida cellae, two new yeast species from the Starmerella clade associated with solitary bees in the Atlantic rain forest of Brazil.

    PubMed

    Pimentel, Mariana R C; Antonini, Yasmine; Martins, Rogério P; Lachance, Marc-André; Rosa, Carlos A

    2005-06-01

    Two new ascomycetous yeast species belonging to the Starmerella clade were discovered in nests of two solitary bee species in the Atlantic rain forest of Brazil. Candida riodocensis was isolated from pollen-nectar provisions, larvae and fecal pellets of nests of Megachile sp., and Candida cellae was found in pollen-nectar provisions of Centris tarsata. Analysis of the sequences of the D1/D2 large-subunit ribosomal DNA showed that C. riodocensis is phylogenetically related to C. batistae, and the closest relative of C. cellae is C. etchellsii. The type strains are C. riodocensis UFMG-MG02 (=CBS 10087(T) = NRRL Y-27859(T)) and C. cellae UFMG-PC04 (=CBS 10086(T) = NRRL Y-27860(T)). PMID:15925316

  16. Catastrophic bifurcations in a second-order dynamical system with application to acid rain and forest collapse

    SciTech Connect

    Muratori, S.; Rinaldi, S. )

    1989-12-01

    A second-order nonlinear dynamical system modelling the interactions of threes and damaging insects in a forest is used to analyze the influence of acidic deposition, an increase of which can cause sudden insect infestations and the collapse of the forest ecosystem. The analysis is carried out by finding the bifurcations of the system and by proving that under suitable conditions, such bifurcations can be catastrophic. In particular, the model explains the case in which the damaging insects are present only at an endemic level as well as the case in which the forest is periodically infested by insects. In the case in which predisposition of forest trees to insect infestation is enhanced by acidic deposition, it is shown that the point at which the first impacts on tree biomass are detectable can be easily quantified by a simple formula which says that the forest that should be affected first are those that have a large carrying capacity of the trees, a large maximum birth rate and a low death rate of the insects, and a low pressure of the predators on the insects. The analysis can also distinguish between smooth impacts (decline of tree biomass) and dramatic impacts (collapse of the forest).

  17. Expression pattern of four storage xyloglucan mobilization-related genes during seedling development of the rain forest tree Hymenaea courbaril L.

    PubMed

    Brandão, A D; Del Bem, L E V; Vincentz, M; Buckeridge, M S

    2009-01-01

    During seedling establishment, cotyledons of the rain forest tree Hymenaea courbaril mobilize storage cell wall xyloglucan to sustain growth. The polysaccharide is degraded and its products are transported to growing sink tissues. Auxin from the shoot controls the level of xyloglucan hydrolytic enzymes. It is not yet known how important the expression of these genes is for the control of storage xyloglucan degradation. In this work, partial cDNAs of the genes xyloglucan transglycosylase hydrolase (HcXTH1) and beta-galactosidase (HcBGAL1), both related to xyloglucan degradation, and two other genes related to sucrose metabolism [alkaline invertase (HcAlkIN1) and sucrose synthase (HcSUS1)], were isolated. The partial sequences were characterized by comparison with sequences available in the literature, and phylogenetic trees were assembled. Gene expression was evaluated at intervals of 6 h during 24 h in cotyledons, hypocotyl, roots, and leaves, using 45-d-old plantlets. HcXTH1 and HcBGAL1 were correlated to xyloglucan degradation and responded to auxin and light, being down-regulated when transport of auxin was prevented by N-1-naphthylphthalamic acid (NPA) and stimulated by constant light. Genes related to sucrose metabolism, HcAlkIN1 and HcSUS1, responded to inhibition of auxin transport in consonance with storage mobilization in the cotyledons. A model is proposed suggesting that auxin and light are involved in the control of the expression of genes related to storage xyloglucan mobilization in seedlings of H. courbaril. It is concluded that gene expression plays a role in the control of the intercommunication system of the source-sink relationship during seeding growth, favouring its establishment in the shaded environment of the rain forest understorey.

  18. Expression pattern of four storage xyloglucan mobilization-related genes during seedling development of the rain forest tree Hymenaea courbaril L.

    PubMed Central

    Brandão, A. D.; Del Bem, L. E. V.; Vincentz, M.; Buckeridge, M. S.

    2009-01-01

    During seedling establishment, cotyledons of the rain forest tree Hymenaea courbaril mobilize storage cell wall xyloglucan to sustain growth. The polysaccharide is degraded and its products are transported to growing sink tissues. Auxin from the shoot controls the level of xyloglucan hydrolytic enzymes. It is not yet known how important the expression of these genes is for the control of storage xyloglucan degradation. In this work, partial cDNAs of the genes xyloglucan transglycosylase hydrolase (HcXTH1) and β-galactosidase (HcBGAL1), both related to xyloglucan degradation, and two other genes related to sucrose metabolism [alkaline invertase (HcAlkIN1) and sucrose synthase (HcSUS1)], were isolated. The partial sequences were characterized by comparison with sequences available in the literature, and phylogenetic trees were assembled. Gene expression was evaluated at intervals of 6 h during 24 h in cotyledons, hypocotyl, roots, and leaves, using 45-d-old plantlets. HcXTH1 and HcBGAL1 were correlated to xyloglucan degradation and responded to auxin and light, being down-regulated when transport of auxin was prevented by N-1-naphthylphthalamic acid (NPA) and stimulated by constant light. Genes related to sucrose metabolism, HcAlkIN1 and HcSUS1, responded to inhibition of auxin transport in consonance with storage mobilization in the cotyledons. A model is proposed suggesting that auxin and light are involved in the control of the expression of genes related to storage xyloglucan mobilization in seedlings of H. courbaril. It is concluded that gene expression plays a role in the control of the intercommunication system of the source–sink relationship during seeding growth, favouring its establishment in the shaded environment of the rain forest understorey. PMID:19221141

  19. Does simulated acid rain increase the leaching of cadmium from wood ash to toxic levels to coniferous forest humus microbes?

    PubMed

    Perkiömäki, Jonna; Fritze, Hannu

    2003-05-01

    Abstract Wood ash contains Cd in concentrations not permitted for fertilization use in agriculture (>3 mg kg(-1)). It has been shown that spiking ash with Cd to concentrations of 1000 mg kg(-1) induced no further changes in humus microbial activity and community structure as ash alone. To accelerate the weathering process and thus to liberate the spiked Cd from the ash, three treatments - wood ash (A), Cd spiked wood ash (ACd, 1000 mg Cd kg(-1) ash), both applied at a fertilization rate of 5000 kg ha(-1), together with a control (C) - were performed in microcosms and incubated in field condition under two types of irrigation - water and simulated acid rain. During the incubation period of one growing season the simulated acid rain plots received a sulfur load of 3.64 g S m(-2), which was 15 times more than the S deposition on the water irrigated plots. The treatments resulted in a mean Cd increase of the humus from 0.23 mg kg(-1) of the C treatment to 0.52 and 39.5 mg kg(-1) of the A and ACd treatments, respectively. The irrigation had no further effect on the result. The microbial activity, measured as soil basal respiration, and the microbial community structure, measured as humus phospholipid fatty acid and 16S and 18S polymerase chain reaction/denaturing gradient gel electrophoresis patterns, changed only due to the ash (A and ACd treatments) fertilization irrespective of the irrigation. The bacterial biosensor, emitting light in the presence of bioavailable Cd, did not react to any of the treatments. This result shows that Cd in ash was not leached into the humus due to increased deposition of acidified rain.

  20. White-lipped peccary (Tayassu pecari, Artiodactyla: Tayassuidae) diet and fruit availability in a Costa Rican rain forest.

    PubMed

    Altrichter, M; Carrillo, E; Sáenz, J; Fuller, T K

    2001-01-01

    We studied fruit availability, diet and habitat use by white-lipped peccary (Tayassu pecari) in Corcovado National Park, southwest Costa Rica, from July 1996 to April 1997. The results show that the availability of important fruits for the white-lipped peccary differs between habitats and climatic seasons. Fruit availability was highest in the primary forest than secondary and coastal forest. There was a period of shortage of fruits to ends of the wet season, during which the consumption of not seasonal resources like leaves and shafts increased. The important fruits during this period of shortage were Ficus sp and Licania operculipetala. The several types of forest were used according to the fruit availability, and it was a direct relation between the consumption and the fruit availability.

  1. Drivers of aboveground wood production in a lowland tropical forest of West Africa: teasing apart the roles of tree density, tree diversity, soil phosphorus, and historical logging.

    PubMed

    Jucker, Tommaso; Sanchez, Aida Cuni; Lindsell, Jeremy A; Allen, Harriet D; Amable, Gabriel S; Coomes, David A

    2016-06-01

    Tropical forests currently play a key role in regulating the terrestrial carbon cycle and abating climate change by storing carbon in wood. However, there remains considerable uncertainty as to whether tropical forests will continue to act as carbon sinks in the face of increased pressure from expanding human activities. Consequently, understanding what drives productivity in tropical forests is critical. We used permanent forest plot data from the Gola Rainforest National Park (Sierra Leone) - one of the largest tracts of intact tropical moist forest in West Africa - to explore how (1) stand basal area and tree diversity, (2) past disturbance associated with past logging, and (3) underlying soil nutrient gradients interact to determine rates of aboveground wood production (AWP). We started by statistically modeling the diameter growth of individual trees and used these models to estimate AWP for 142 permanent forest plots. We then used structural equation modeling to explore the direct and indirect pathways which shape rates of AWP. Across the plot network, stand basal area emerged as the strongest determinant of AWP, with densely packed stands exhibiting the fastest rates of AWP. In addition to stand packing density, both tree diversity and soil phosphorus content were also positively related to productivity. By contrast, historical logging activities negatively impacted AWP through the removal of large trees, which contributed disproportionately to productivity. Understanding what determines variation in wood production across tropical forest landscapes requires accounting for multiple interacting drivers - with stand structure, tree diversity, and soil nutrients all playing a key role. Importantly, our results also indicate that logging activities can have a long-lasting impact on a forest's ability to sequester and store carbon, emphasizing the importance of safeguarding old-growth tropical forests.

  2. Drivers of aboveground wood production in a lowland tropical forest of West Africa: teasing apart the roles of tree density, tree diversity, soil phosphorus, and historical logging.

    PubMed

    Jucker, Tommaso; Sanchez, Aida Cuni; Lindsell, Jeremy A; Allen, Harriet D; Amable, Gabriel S; Coomes, David A

    2016-06-01

    Tropical forests currently play a key role in regulating the terrestrial carbon cycle and abating climate change by storing carbon in wood. However, there remains considerable uncertainty as to whether tropical forests will continue to act as carbon sinks in the face of increased pressure from expanding human activities. Consequently, understanding what drives productivity in tropical forests is critical. We used permanent forest plot data from the Gola Rainforest National Park (Sierra Leone) - one of the largest tracts of intact tropical moist forest in West Africa - to explore how (1) stand basal area and tree diversity, (2) past disturbance associated with past logging, and (3) underlying soil nutrient gradients interact to determine rates of aboveground wood production (AWP). We started by statistically modeling the diameter growth of individual trees and used these models to estimate AWP for 142 permanent forest plots. We then used structural equation modeling to explore the direct and indirect pathways which shape rates of AWP. Across the plot network, stand basal area emerged as the strongest determinant of AWP, with densely packed stands exhibiting the fastest rates of AWP. In addition to stand packing density, both tree diversity and soil phosphorus content were also positively related to productivity. By contrast, historical logging activities negatively impacted AWP through the removal of large trees, which contributed disproportionately to productivity. Understanding what determines variation in wood production across tropical forest landscapes requires accounting for multiple interacting drivers - with stand structure, tree diversity, and soil nutrients all playing a key role. Importantly, our results also indicate that logging activities can have a long-lasting impact on a forest's ability to sequester and store carbon, emphasizing the importance of safeguarding old-growth tropical forests. PMID:27516859

  3. Cocoa Intensification Scenarios and Their Predicted Impact on CO2 Emissions, Biodiversity Conservation, and Rural Livelihoods in the Guinea Rain Forest of West Africa

    NASA Astrophysics Data System (ADS)

    Gockowski, Jim; Sonwa, Denis

    2011-08-01

    The Guinean rain forest (GRF) of West Africa, identified over 20 years ago as a global biodiversity hotspot, had reduced to 113,000 km2 at the start of the new millennium which was 18% of its original area. The principal driver of this environmental change has been the expansion of extensive smallholder agriculture. From 1988 to 2007, the area harvested in the GRF by smallholders of cocoa, cassava, and oil palm increased by 68,000 km2. Field results suggest a high potential for significantly increasing crop yields through increased application of seed-fertilizer technologies. Analyzing land-use change scenarios, it was estimated that had intensified cocoa technology, already developed in the 1960s, been pursued in Cote d'Ivoire, Ghana, Nigeria and Cameroon that over 21,000 km2 of deforestation and forest degradation could have been avoided along with the emission of nearly 1.4 billion t of CO2. Addressing the low productivity of agriculture in the GRF should be one of the principal objectives of REDD climate mitigation programs.

  4. High CO2 concentration increases relative leaf carbon gain under dynamic light in Dipterocarpus sublamellatus seedlings in a tropical rain forest, Malaysia.

    PubMed

    Tomimatsu, Hajime; Iio, Atsuhiro; Adachi, Minaco; Saw, Leng-Guan; Fletcher, Christine; Tang, Yanhong

    2014-09-01

    Understory plants in tropical forests often experience a low-light environment combined with high CO2 concentration. We hypothesized that the high CO2 concentration may compensate for leaf carbon loss caused by the low light, through increasing light-use efficiency of both steady-state and dynamic photosynthetic properties. To test the hypothesis, we examined CO2 gas exchange in response to an artificial lightfleck in Dipterocarpus sublamellatus Foxw. seedlings under contrasting CO2 conditions: 350 and 700 μmol CO2 mol(-1) air in a tropical rain forest, Pasoh, Malaysia. Total photosynthetic carbon gain from the lightfleck was about double when subjected to the high CO2 when compared with the low CO2 concentration. The increase of light-use efficiency in dynamic photosynthesis contributed 7% of the increased carbon gain, most of which was due to reduction of photosynthetic induction to light increase under the high CO2. The light compensation point of photosynthesis decreased by 58% and the apparent quantum yield increased by 26% at the high CO2 compared with those at the low CO2. The study suggests that high CO2 increases photosynthetic light-use efficiency under both steady-state and fluctuating light conditions, which should be considered in assessing the leaf carbon gain of understory plants in low-light environments.

  5. Cocoa intensification scenarios and their predicted impact on CO₂ emissions, biodiversity conservation, and rural livelihoods in the Guinea rain forest of West Africa.

    PubMed

    Gockowski, Jim; Sonwa, Denis

    2011-08-01

    The Guinean rain forest (GRF) of West Africa, identified over 20 years ago as a global biodiversity hotspot, had reduced to 113,000 km² at the start of the new millennium which was 18% of its original area. The principal driver of this environmental change has been the expansion of extensive smallholder agriculture. From 1988 to 2007, the area harvested in the GRF by smallholders of cocoa, cassava, and oil palm increased by 68,000 km². Field results suggest a high potential for significantly increasing crop yields through increased application of seed-fertilizer technologies. Analyzing land-use change scenarios, it was estimated that had intensified cocoa technology, already developed in the 1960s, been pursued in Cote d'Ivoire, Ghana, Nigeria and Cameroon that over 21,000 km² of deforestation and forest degradation could have been avoided along with the emission of nearly 1.4 billion t of CO₂. Addressing the low productivity of agriculture in the GRF should be one of the principal objectives of REDD climate mitigation programs.

  6. Whither acid rain?

    PubMed

    Brimblecombe, P

    2001-04-01

    Acid rain, the environmental cause célèbre of the 1980s seems to have vanished from popular conscience. By contrast, scientific research, despite funding difficulties, has continued to produce hundreds of research papers each year. Studies of acid rain taught much about precipitation chemistry, the behaviour of snow packs, long-range transport of pollutants and new issues in the biology of fish and forested ecosystems. There is now evidence of a shift away from research in precipitation and sulfur chemistry, but an impressive theoretical base remains as a legacy.

  7. Soil Changes Induced by Rubber and Tea Plantation Establishment: Comparison with Tropical Rain Forest Soil in Xishuangbanna, SW China

    NASA Astrophysics Data System (ADS)

    Li, Hongmei; Ma, Youxin; Liu, Wenjie; Liu, Wenjun

    2012-11-01

    Over the past thirty years, Xishuangbanna in Southwestern China has seen dramatic changes in land use where large areas of tropical forest and fallow land have been converted to rubber and tea plantations. In this study we evaluated the effects of land use and slope on soil properties in seven common disturbed and undisturbed land-types. Results indicated that all soils were acidic, with pH values significantly higher in the 3- and 28-year-old rubber plantations. The tropical forests had the lowest bulk densities, especially significantly lower from the top 10 cm of soil, and highest soil organic matter concentrations. Soil moisture content at topsoil was highest in the mature rubber plantation. Soils in the tropical forests and abandoned cultivated land had inorganic N (IN) concentrations approximately equal in NH4 +-N and NO3 --N. However, soil IN pools were dominated by NH4 +-N in the rubber and tea plantations. This trend suggests that conversion of tropical forest to rubber and tea plantations increases NH4 +-N concentration and decreases NO3 --N concentration, with the most pronounced effect in plantations that are more frequently fertilized. Soil moisture content, IN, NH4 +-N and NO3 --N concentrations within all sites were higher in the rainy season than in the dry season. Significant differences in the soil moisture content, and IN, NH4 +-N and NO3 --N concentration was detected for both land uses and sampling season effects, as well as interactions. Higher concentrations of NH4 +-N were measured at the upper slopes of all sites, but NO3 --N concentrations were highest at the lower slope in the rubber plantations and lowest at the lower slopes at all other. Thus, the conversion of tropical forests to rubber and tea plantations can have a profound effect on soil NH4 +-N and NO3 --N concentrations. Options for improved soil management in plantations are discussed.

  8. Soil changes induced by rubber and tea plantation establishment: comparison with tropical rain forest soil in Xishuangbanna, SW China.

    PubMed

    Li, Hongmei; Ma, Youxin; Liu, Wenjie; Liu, Wenjun

    2012-11-01

    Over the past thirty years, Xishuangbanna in Southwestern China has seen dramatic changes in land use where large areas of tropical forest and fallow land have been converted to rubber and tea plantations. In this study we evaluated the effects of land use and slope on soil properties in seven common disturbed and undisturbed land-types. Results indicated that all soils were acidic, with pH values significantly higher in the 3- and 28-year-old rubber plantations. The tropical forests had the lowest bulk densities, especially significantly lower from the top 10 cm of soil, and highest soil organic matter concentrations. Soil moisture content at topsoil was highest in the mature rubber plantation. Soils in the tropical forests and abandoned cultivated land had inorganic N (IN) concentrations approximately equal in NH(4) (+)-N and NO(3) (-)-N. However, soil IN pools were dominated by NH(4) (+)-N in the rubber and tea plantations. This trend suggests that conversion of tropical forest to rubber and tea plantations increases NH(4) (+)-N concentration and decreases NO(3) (-)-N concentration, with the most pronounced effect in plantations that are more frequently fertilized. Soil moisture content, IN, NH(4) (+)-N and NO(3) (-)-N concentrations within all sites were higher in the rainy season than in the dry season. Significant differences in the soil moisture content, and IN, NH(4) (+)-N and NO(3) (-)-N concentration was detected for both land uses and sampling season effects, as well as interactions. Higher concentrations of NH(4) (+)-N were measured at the upper slopes of all sites, but NO(3) (-)-N concentrations were highest at the lower slope in the rubber plantations and lowest at the lower slopes at all other. Thus, the conversion of tropical forests to rubber and tea plantations can have a profound effect on soil NH(4) (+)-N and NO(3) (-)-N concentrations. Options for improved soil management in plantations are discussed.

  9. Soil changes induced by rubber and tea plantation establishment: comparison with tropical rain forest soil in Xishuangbanna, SW China.

    PubMed

    Li, Hongmei; Ma, Youxin; Liu, Wenjie; Liu, Wenjun

    2012-11-01

    Over the past thirty years, Xishuangbanna in Southwestern China has seen dramatic changes in land use where large areas of tropical forest and fallow land have been converted to rubber and tea plantations. In this study we evaluated the effects of land use and slope on soil properties in seven common disturbed and undisturbed land-types. Results indicated that all soils were acidic, with pH values significantly higher in the 3- and 28-year-old rubber plantations. The tropical forests had the lowest bulk densities, especially significantly lower from the top 10 cm of soil, and highest soil organic matter concentrations. Soil moisture content at topsoil was highest in the mature rubber plantation. Soils in the tropical forests and abandoned cultivated land had inorganic N (IN) concentrations approximately equal in NH(4) (+)-N and NO(3) (-)-N. However, soil IN pools were dominated by NH(4) (+)-N in the rubber and tea plantations. This trend suggests that conversion of tropical forest to rubber and tea plantations increases NH(4) (+)-N concentration and decreases NO(3) (-)-N concentration, with the most pronounced effect in plantations that are more frequently fertilized. Soil moisture content, IN, NH(4) (+)-N and NO(3) (-)-N concentrations within all sites were higher in the rainy season than in the dry season. Significant differences in the soil moisture content, and IN, NH(4) (+)-N and NO(3) (-)-N concentration was detected for both land uses and sampling season effects, as well as interactions. Higher concentrations of NH(4) (+)-N were measured at the upper slopes of all sites, but NO(3) (-)-N concentrations were highest at the lower slope in the rubber plantations and lowest at the lower slopes at all other. Thus, the conversion of tropical forests to rubber and tea plantations can have a profound effect on soil NH(4) (+)-N and NO(3) (-)-N concentrations. Options for improved soil management in plantations are discussed. PMID:22986585

  10. Convergent structural responses of tropical forests to diverse disturbance regimes.

    PubMed

    Kellner, James R; Asner, Gregory P

    2009-09-01

    Size frequency distributions of canopy gaps are a hallmark of forest dynamics. But it remains unknown whether legacies of forest disturbance are influencing vertical size structure of landscapes, or space-filling in the canopy volume. We used data from LiDAR remote sensing to quantify distributions of canopy height and sizes of 434,501 canopy gaps in five tropical rain forest landscapes in Costa Rica and Hawaii. The sites represented a wide range of variation in structure and natural disturbance history, from canopy gap dynamics in lowland Costa Rica and Hawaii, to stages and types of stand-level dieback on upland Mauna Kea and Kohala volcanoes. Large differences in vertical canopy structure characterized these five tropical rain forest landscapes, some of which were related to known disturbance events. Although there were quantitative differences in the values of scaling exponents within and among sites, size frequency distributions of canopy gaps followed power laws at all sites and in all canopy height classes. Scaling relationships in gap size at different heights in the canopy were qualitatively similar at all sites, revealing a remarkable similarity despite clearly defined differences in species composition and modes of prevailing disturbance. These findings indicate that power-law gap-size frequency distributions are ubiquitous features of these five tropical rain forest landscapes, and suggest that mechanisms of forest disturbance may be secondary to other processes in determining vertical and horizontal size structure in canopies. PMID:19614757

  11. Convergent structural responses of tropical forests to diverse disturbance regimes.

    PubMed

    Kellner, James R; Asner, Gregory P

    2009-09-01

    Size frequency distributions of canopy gaps are a hallmark of forest dynamics. But it remains unknown whether legacies of forest disturbance are influencing vertical size structure of landscapes, or space-filling in the canopy volume. We used data from LiDAR remote sensing to quantify distributions of canopy height and sizes of 434,501 canopy gaps in five tropical rain forest landscapes in Costa Rica and Hawaii. The sites represented a wide range of variation in structure and natural disturbance history, from canopy gap dynamics in lowland Costa Rica and Hawaii, to stages and types of stand-level dieback on upland Mauna Kea and Kohala volcanoes. Large differences in vertical canopy structure characterized these five tropical rain forest landscapes, some of which were related to known disturbance events. Although there were quantitative differences in the values of scaling exponents within and among sites, size frequency distributions of canopy gaps followed power laws at all sites and in all canopy height classes. Scaling relationships in gap size at different heights in the canopy were qualitatively similar at all sites, revealing a remarkable similarity despite clearly defined differences in species composition and modes of prevailing disturbance. These findings indicate that power-law gap-size frequency distributions are ubiquitous features of these five tropical rain forest landscapes, and suggest that mechanisms of forest disturbance may be secondary to other processes in determining vertical and horizontal size structure in canopies.

  12. An ant-plant by-product mutualism is robust to selective logging of rain forest and conversion to oil palm plantation.

    PubMed

    Fayle, Tom M; Edwards, David P; Foster, William A; Yusah, Kalsum M; Turner, Edgar C

    2015-06-01

    Anthropogenic disturbance and the spread of non-native species disrupt natural communities, but also create novel interactions between species. By-product mutualisms, in which benefits accrue as side effects of partner behaviour or morphology, are often non-specific and hence may persist in novel ecosystems. We tested this hypothesis for a two-way by-product mutualism between epiphytic ferns and their ant inhabitants in the Bornean rain forest, in which ants gain housing in root-masses while ferns gain protection from herbivores. Specifically, we assessed how the specificity (overlap between fern and ground-dwelling ants) and the benefits of this interaction are altered by selective logging and conversion to an oil palm plantation habitat. We found that despite the high turnover of ant species, ant protection against herbivores persisted in modified habitats. However, in ferns growing in the oil palm plantation, ant occupancy, abundance and species richness declined, potentially due to the harsher microclimate. The specificity of the fern-ant interactions was also lower in the oil palm plantation habitat than in the forest habitats. We found no correlations between colony size and fern size in modified habitats, and hence no evidence for partner fidelity feedbacks, in which ants are incentivised to protect fern hosts. Per species, non-native ant species in the oil palm plantation habitat (18 % of occurrences) were as important as native ones in terms of fern protection and contributed to an increase in ant abundance and species richness with fern size. We conclude that this by-product mutualism persists in logged forest and oil palm plantation habitats, with no detectable shift in partner benefits. Such persistence of generalist interactions in novel ecosystems may be important for driving ecosystem functioning. PMID:25575674

  13. An ant-plant by-product mutualism is robust to selective logging of rain forest and conversion to oil palm plantation.

    PubMed

    Fayle, Tom M; Edwards, David P; Foster, William A; Yusah, Kalsum M; Turner, Edgar C

    2015-06-01

    Anthropogenic disturbance and the spread of non-native species disrupt natural communities, but also create novel interactions between species. By-product mutualisms, in which benefits accrue as side effects of partner behaviour or morphology, are often non-specific and hence may persist in novel ecosystems. We tested this hypothesis for a two-way by-product mutualism between epiphytic ferns and their ant inhabitants in the Bornean rain forest, in which ants gain housing in root-masses while ferns gain protection from herbivores. Specifically, we assessed how the specificity (overlap between fern and ground-dwelling ants) and the benefits of this interaction are altered by selective logging and conversion to an oil palm plantation habitat. We found that despite the high turnover of ant species, ant protection against herbivores persisted in modified habitats. However, in ferns growing in the oil palm plantation, ant occupancy, abundance and species richness declined, potentially due to the harsher microclimate. The specificity of the fern-ant interactions was also lower in the oil palm plantation habitat than in the forest habitats. We found no correlations between colony size and fern size in modified habitats, and hence no evidence for partner fidelity feedbacks, in which ants are incentivised to protect fern hosts. Per species, non-native ant species in the oil palm plantation habitat (18 % of occurrences) were as important as native ones in terms of fern protection and contributed to an increase in ant abundance and species richness with fern size. We conclude that this by-product mutualism persists in logged forest and oil palm plantation habitats, with no detectable shift in partner benefits. Such persistence of generalist interactions in novel ecosystems may be important for driving ecosystem functioning.

  14. Highly local environmental variability promotes intrapopulation divergence of quantitative traits: an example from tropical rain forest trees

    PubMed Central

    Brousseau, Louise; Bonal, Damien; Cigna, Jeremy; Scotti, Ivan

    2013-01-01

    Background and Aims In habitat mosaics, plant populations face environmental heterogeneity over short geographical distances. Such steep environmental gradients can induce ecological divergence. Lowland rainforests of the Guiana Shield are characterized by sharp, short-distance environmental variations related to topography and soil characteristics (from waterlogged bottomlands on hydromorphic soils to well-drained terra firme on ferralitic soils). Continuous plant populations distributed along such gradients are an interesting system to study intrapopulation divergence at highly local scales. This study tested (1) whether conspecific populations growing in different habitats diverge at functional traits, and (2) whether they diverge in the same way as congeneric species having different habitat preferences. Methods Phenotypic differentiation was studied within continuous populations occupying different habitats for two congeneric, sympatric, and ecologically divergent tree species (Eperua falcata and E. grandiflora, Fabaceae). Over 3000 seeds collected from three habitats were germinated and grown in a common garden experiment, and 23 morphological, biomass, resource allocation and physiological traits were measured. Key Results In both species, seedling populations native of different habitats displayed phenotypic divergence for several traits (including seedling growth, biomass allocation, leaf chemistry, photosynthesis and carbon isotope composition). This may occur through heritable genetic variation or other maternally inherited effects. For a sub-set of traits, the intraspecific divergence associated with environmental variation coincided with interspecific divergence. Conclusions The results indicate that mother trees from different habitats transmit divergent trait values to their progeny, and suggest that local environmental variation selects for different trait optima even at a very local spatial scale. Traits for which differentiation within species

  15. Do epigeal termite mounds increase the diversity of plant habitats in a tropical rain forest in peninsular Malaysia?

    PubMed

    Beaudrot, Lydia; Du, Yanjun; Rahman Kassim, Abdul; Rejmánek, Marcel; Harrison, Rhett D

    2011-01-01

    The extent to which environmental heterogeneity can account for tree species coexistence in diverse ecosystems, such as tropical rainforests, is hotly debated, although the importance of spatial variability in contributing to species co-existence is well recognized. Termites contribute to the micro-topographical and nutrient spatial heterogeneity of tropical forests. We therefore investigated whether epigeal termite mounds could contribute to the coexistence of plant species within a 50 ha plot at Pasoh Forest Reserve, Malaysia. Overall, stem density was significantly higher on mounds than in their immediate surroundings, but tree species diversity was significantly lower. Canonical correspondence analysis showed that location on or off mounds significantly influenced species distribution when stems were characterized by basal area. Like studies of termite mounds in other ecosystems, our results suggest that epigeal termite mounds provide a specific microhabitat for the enhanced growth and survival of certain species in these species-rich tropical forests. However, the extent to which epigeal termite mounds facilitate species coexistence warrants further investigation.

  16. Acid rain

    SciTech Connect

    Elsworth, S.

    1985-01-01

    This book was written in a concise and readable style for the lay public. It's purpose was to make the public aware of the damage caused by acid rain and to mobilize public opinion to favor the elimination of the causes of acid rain.

  17. Acid rain

    SciTech Connect

    White, J.C. )

    1988-01-01

    This book presents the proceedings of the third annual conference sponsored by the Acid Rain Information Clearinghouse (ARIC). Topics covered include: Legal aspects of the source-receptor relationship: an energy perspective; Scientific uncertainty, agency inaction, and the courts; and Acid rain: the emerging legal framework.

  18. Acid Rain.

    ERIC Educational Resources Information Center

    Openshaw, Peter

    1987-01-01

    Provides some background information on acid deposition. Includes a historical perspective, describes some effects of acid precipitation, and discusses acid rain in the United Kingdom. Contains several experiments that deal with the effects of acid rain on water quality and soil. (TW)

  19. Air pollution and changes in forest nitrogen status: Fog and rain deposition and nitrogen losses from forested watersheds in the San Bernardino Mountains. Final report

    SciTech Connect

    Fenn, M.E.; Poth, M.A.

    1998-08-01

    The primary objective of this project was to examine the effects of N deposition on mixed conifer forests in southern California. Studies were conducted at selected sites an air pollution gradient in the San Bernardino Mountains (SBM). The main tasks were: (1) to measure N deposition to the forest in fog and throughfall, (2) to determine spatial and temporal patterns of nitrate export in stream water, and (3) to quantify trace gas fluxes from soil at sites with high and low N deposition. Fog was found to be an important N source at the western end of the SMB due to his high frequency and presence at elevated concentrations. N deposition from throughfall was found to be similar to levels in forests where adverse effects have occurred. Annual fluxes of N from soil were 18-times higher at the western end of the SBM than at the eastern end. The data provide evidence of forest nitrogen saturation caused by the deposition of anthropogenic pollutants over a multi-decade period in the SBM.

  20. Phyllosphere nitrogen relations: reciprocal transfer of nitrogen between epiphyllous liverworts and host plants in the understorey of a lowland tropical wet forest in Costa Rica.

    PubMed

    Wanek, Wolfgang; Pörtl, Katja

    2005-05-01

    Epiphyllous bryophytes on tropical rainforest plants acquire nutrients from throughfall and free-living N2-fixing organisms, but may also depend directly on host leaf leachates. By contrast, after drying events bryophytes lose significant quantities of nutrients through leaching that can be taken up by host leaves. To assess a potential nutritional interdependency, nitrogen fluxes between epiphyllous liverworts and their host leaves (Carludovica drudei, Costus laevis, Dieffenbachia concinna, Pentagonia wendlandii) were quantified by in situ15N-labelling techniques in a lowland rainforest, Piedras Blancas National Park, Costa Rica. Depending on host species, epiphyllous bryophytes met between 1 and 57% of their N demand from host leaf leachates. Externally supplied 15N was taken up both by epiphylls and host leaves, but N from epiphyll leachates accounted for < 2.5% of host leaf N after 14 d. Long-term observations (180 d) demonstrated the highly dynamic nature of phyllosphere N of the investigated tropical rainforest understorey and an intermittent sink capacity of epiphyllous bryophytes.

  1. Functional Diversity of Photosynthetic Light Use of 16 Vascular Epiphyte Species Under Fluctuating Irradiance in the Canopy of a Giant Virola michelii (Myristicaceae) Tree in the Tropical Lowland Forest of French Guyana

    PubMed Central

    Rascher, Uwe; Freiberg, Martin; Lüttge, Ulrich

    2011-01-01

    Here we present the first study, in which a large number of different vascular epiphyte species were measured for their photosynthetic performance in the natural environment of their phorophyte in the lowland rainforest of French Guyana. More than 70 epiphyte species covered the host tree in a dense cover. Of these, the photosynthesis of 16 abundant species was analyzed intensely over several months. Moreover, the light environment was characterized with newly developed light sensors that recorded continuously and with high temporal resolution light intensity next to the epiphytes. Light intensity was highly fluctuating and showed great site specific spatio-temporal variations of photosynthetic photon flux. Using a novel computer routine we quantified the integrated light intensity the epiphytes were exposed to in a 3 h window and we related this light intensity to measurements of the actual photosynthetic status. It could be shown that the photosynthetic apparatus of the epiphytes was well adapted to the quickly changing light conditions. Some of the epiphytes were chronically photoinhibited at predawn and significant acute photoinhibition, expressed by a reduction of potential quantum efficiency (Fv/Fm)30′, was observed during the day. By correlating (Fv/Fm)30′ to the integrated and weighted light intensity perceived during the previous 3 h, it became clear that acute photoinhibition was related to light environment prior to the measurements. Additionally photosynthetic performance was not determined by rain events, with the exception of an Aechmea species. This holds true for all the other 15 species of this study and we thus conclude that actual photosynthesis of these tropical epiphytes was determined by the specific and fluctuating light conditions of their microhabitat and cannot be simply attributed to light-adapted ancestors. PMID:22629271

  2. Conversion of lowland tropical forests to tree cash crop plantations loses up to one-half of stored soil organic carbon

    PubMed Central

    van Straaten, Oliver; Corre, Marife D.; Wolf, Katrin; Tchienkoua, Martin; Cuellar, Eloy; Matthews, Robin B.; Veldkamp, Edzo

    2015-01-01

    Tropical deforestation for the establishment of tree cash crop plantations causes significant alterations to soil organic carbon (SOC) dynamics. Despite this recognition, the current Intergovernmental Panel on Climate Change (IPCC) tier 1 method has a SOC change factor of 1 (no SOC loss) for conversion of forests to perennial tree crops, because of scarcity of SOC data. In this pantropic study, conducted in active deforestation regions of Indonesia, Cameroon, and Peru, we quantified the impact of forest conversion to oil palm (Elaeis guineensis), rubber (Hevea brasiliensis), and cacao (Theobroma cacao) agroforestry plantations on SOC stocks within 3-m depth in deeply weathered mineral soils. We also investigated the underlying biophysical controls regulating SOC stock changes. Using a space-for-time substitution approach, we compared SOC stocks from paired forests (n = 32) and adjacent plantations (n = 54). Our study showed that deforestation for tree plantations decreased SOC stocks by up to 50%. The key variable that predicted SOC changes across plantations was the amount of SOC present in the forest before conversion—the higher the initial SOC, the higher the loss. Decreases in SOC stocks were most pronounced in the topsoil, although older plantations showed considerable SOC losses below 1-m depth. Our results suggest that (i) the IPCC tier 1 method should be revised from its current SOC change factor of 1 to 0.6 ± 0.1 for oil palm and cacao agroforestry plantations and 0.8 ± 0.3 for rubber plantations in the humid tropics; and (ii) land use management policies should protect natural forests on carbon-rich mineral soils to minimize SOC losses. PMID:26217000

  3. Conversion of lowland tropical forests to tree cash crop plantations loses up to one-half of stored soil organic carbon.

    PubMed

    van Straaten, Oliver; Corre, Marife D; Wolf, Katrin; Tchienkoua, Martin; Cuellar, Eloy; Matthews, Robin B; Veldkamp, Edzo

    2015-08-11

    Tropical deforestation for the establishment of tree cash crop plantations causes significant alterations to soil organic carbon (SOC) dynamics. Despite this recognition, the current Intergovernmental Panel on Climate Change (IPCC) tier 1 method has a SOC change factor of 1 (no SOC loss) for conversion of forests to perennial tree crops, because of scarcity of SOC data. In this pantropic study, conducted in active deforestation regions of Indonesia, Cameroon, and Peru, we quantified the impact of forest conversion to oil palm (Elaeis guineensis), rubber (Hevea brasiliensis), and cacao (Theobroma cacao) agroforestry plantations on SOC stocks within 3-m depth in deeply weathered mineral soils. We also investigated the underlying biophysical controls regulating SOC stock changes. Using a space-for-time substitution approach, we compared SOC stocks from paired forests (n = 32) and adjacent plantations (n = 54). Our study showed that deforestation for tree plantations decreased SOC stocks by up to 50%. The key variable that predicted SOC changes across plantations was the amount of SOC present in the forest before conversion--the higher the initial SOC, the higher the loss. Decreases in SOC stocks were most pronounced in the topsoil, although older plantations showed considerable SOC losses below 1-m depth. Our results suggest that (i) the IPCC tier 1 method should be revised from its current SOC change factor of 1 to 0.6 ± 0.1 for oil palm and cacao agroforestry plantations and 0.8 ± 0.3 for rubber plantations in the humid tropics; and (ii) land use management policies should protect natural forests on carbon-rich mineral soils to minimize SOC losses. PMID:26217000

  4. Conversion of lowland tropical forests to tree cash crop plantations loses up to one-half of stored soil organic carbon.

    PubMed

    van Straaten, Oliver; Corre, Marife D; Wolf, Katrin; Tchienkoua, Martin; Cuellar, Eloy; Matthews, Robin B; Veldkamp, Edzo

    2015-08-11

    Tropical deforestation for the establishment of tree cash crop plantations causes significant alterations to soil organic carbon (SOC) dynamics. Despite this recognition, the current Intergovernmental Panel on Climate Change (IPCC) tier 1 method has a SOC change factor of 1 (no SOC loss) for conversion of forests to perennial tree crops, because of scarcity of SOC data. In this pantropic study, conducted in active deforestation regions of Indonesia, Cameroon, and Peru, we quantified the impact of forest conversion to oil palm (Elaeis guineensis), rubber (Hevea brasiliensis), and cacao (Theobroma cacao) agroforestry plantations on SOC stocks within 3-m depth in deeply weathered mineral soils. We also investigated the underlying biophysical controls regulating SOC stock changes. Using a space-for-time substitution approach, we compared SOC stocks from paired forests (n = 32) and adjacent plantations (n = 54). Our study showed that deforestation for tree plantations decreased SOC stocks by up to 50%. The key variable that predicted SOC changes across plantations was the amount of SOC present in the forest before conversion--the higher the initial SOC, the higher the loss. Decreases in SOC stocks were most pronounced in the topsoil, although older plantations showed considerable SOC losses below 1-m depth. Our results suggest that (i) the IPCC tier 1 method should be revised from its current SOC change factor of 1 to 0.6 ± 0.1 for oil palm and cacao agroforestry plantations and 0.8 ± 0.3 for rubber plantations in the humid tropics; and (ii) land use management policies should protect natural forests on carbon-rich mineral soils to minimize SOC losses.

  5. Territorial organization of the lowland classic maya.

    PubMed

    Marcus, J

    1973-06-01

    Thus far I have discussed ancient Maya sociopolitical structure from the upper levels of the hierarchy downward. Let me now summarize their territorial organization from the bottom upward, starting at the hamlet level (Fig. 8). The smallest unit of settlement-one usually overlooked by archeological surveys in the lowland rain forest-was probably a cluster of thatched huts occupied by a group of related families; larger clusters may have been divided into four quadrants along the lines suggested by Coe (26). Because of the long fallow period (6 to 8 years) characteristic of slash-and-burn agriculture in the Petén, these small hamlets are presumed to have changed location over the years, although they probably shifted in a somewhat circular fashion around a tertiary ceremonial-civic center for whose maintenance they were partly responsible. These tertiary centers were spaced at fairly regular intervals around secondary ceremonial-civic centers with pyramids, carved monuments, and palace-like residences. In turn, the secondary centers occurred at such regular intervals as to form hexagonal patterns around primary centers, which were still larger, with acropolises, multiple ceremonial plazas, and greater numbers of monuments. In some cases, the distance between secondary centers was roughly twice the distance between secondary and tertiary centers, creating a lattice of nested hexagonal cells. This pattern, which conforms to a Western theoretical construct, was presumably caused by factors of service function, travel, and transport. The pattern was not recognized by the Maya at all. They simply recognized that a whole series of smaller centers were dependent on a primary center and therefore mentioned its emblem glyph. Linking the centers of the various hexagons were marriage alliances between members of royal dynasties, who had no kinship ties with the farmers in the hamlets. Out of the large number of primary centers available to them, the Maya selected four as

  6. Wild Pigs (Sus scrofa) Mediate Large-Scale Edge Effects in a Lowland Tropical Rainforest in Peninsular Malaysia

    PubMed Central

    Fujinuma, Junichi; Harrison, Rhett D.

    2012-01-01

    Edge-effects greatly extend the area of tropical forests degraded through human activities. At Pasoh, Peninsular Malaysia, it has been suggested that soil disturbance by highly abundant wild pigs (Sus scrofa), which feed in adjacent Oil Palm plantations, may have mediated the invasion of Clidemia hirta (Melastomataceae) into the diverse tropical lowland rain forest. To investigate this hypothesis, we established three 1 km transects from the forest/Oil Palm plantation boundary into the forest interior. We recorded the distribution of soil disturbance by wild pigs, C. hirta abundance, and environmental variables. These data were analyzed using a hierarchical Bayesian model that incorporated spatial auto-correlation in the environmental variables. As predicted, soil disturbance by wild pigs declined with distance from forest edge and C. hirta abundance was correlated with the level of soil disturbance. Importantly there was no effect of distance on C. hirta abundance, after controlling for the effect of soil disturbance. Clidemia hirta abundance was also correlated with the presence of canopy openings, but there was no significant association between the occurrence of canopy openings and distance from the edge. Increased levels of soil disturbance and C. hirta abundance were still detectable approximately 1 km from the edge, demonstrating the potential for exceptionally large-scale animal mediated edge effects. PMID:22615977

  7. Rainfall-soil moisture relations in landslide-prone areas of a tropical rain forest, Puerto Rico

    USGS Publications Warehouse

    Larsen, Matthew C.; Torres-Sanchez, Angel J.; Krishna, J.H.; Quinones-Aponte, Vicente; Gomez-Gomez, Fernando; Morris, G.L.

    1990-01-01

    Detailed studies of the relation between rainfall and soil moisture are underway at two forested sites on slopes in the CNF. Soil at the sites is characterized by a layer of silty-clay colluvial soil about 1 m thick, which is underlain by up to 10 m of saprolite, and overlies weathered volcaniclastic or quartz-diorite bedrock. Although considerable surface runoff has been observed at the study sites, data show moderate to rapid increases in pore pressure in repsonse to short duration storm events. Pore-pressure increases are greatest in the lower sections of concave slopes apparently due to convergent flow. It is anticipated that these pore-pressure data will provide a means of assessing rainfall characteristics leading to landslide initiation as well as insight to the mechanics of shallow landslides

  8. Environmental factors affecting the distribution of land snails in the Atlantic Rain Forest of Ilha Grande, Angra dos Reis, RJ, Brazil.

    PubMed

    Nunes, G K M; Santos, S B

    2012-02-01

    The distribution and abundance of terrestrial molluscs are affected by environmental factors, but data are lacking for Brazilian land snails. The aim of this study was to understand the relationship between measured environmental factors and the land-snail species composition of two hillsides covered with Atlantic Rain Forest on Ilha Grande. On each hillside, five plots located at 100 m intervals between 100 to 500 m asl were chosen. Each plot was sampled by carrying out timed searches and collecting and sorting litter samples from ten quadrats of 25 × 75 cm. A range of environmental data was measured for each of the quadrats in a plot. A Cluster Analysis was carried out for the richness and abundance data. The environmental variables were analysed using a Pearson Correlation Matrix and Discriminant Analysis. Our re