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Sample records for savanna landscape developing

  1. Ecological Thresholds in the Savanna Landscape: Developing a Protocol for Monitoring the Change in Composition and Utilisation of Large Trees

    PubMed Central

    Druce, Dave J.; Shannon, Graeme; Page, Bruce R.; Grant, Rina; Slotow, Rob

    2008-01-01

    Background Acquiring greater understanding of the factors causing changes in vegetation structure - particularly with the potential to cause regime shifts - is important in adaptively managed conservation areas. Large trees (≥5 m in height) play an important ecosystem function, and are associated with a stable ecological state in the African savanna. There is concern that large tree densities are declining in a number of protected areas, including the Kruger National Park, South Africa. In this paper the results of a field study designed to monitor change in a savanna system are presented and discussed. Methodology/Principal Findings Developing the first phase of a monitoring protocol to measure the change in tree species composition, density and size distribution, whilst also identifying factors driving change. A central issue is the discrete spatial distribution of large trees in the landscape, making point sampling approaches relatively ineffective. Accordingly, fourteen 10 m wide transects were aligned perpendicular to large rivers (3.0–6.6 km in length) and eight transects were located at fixed-point photographic locations (1.0–1.6 km in length). Using accumulation curves, we established that the majority of tree species were sampled within 3 km. Furthermore, the key ecological drivers (e.g. fire, herbivory, drought and disease) which influence large tree use and impact were also recorded within 3 km. Conclusions/Significance The technique presented provides an effective method for monitoring changes in large tree abundance, size distribution and use by the main ecological drivers across the savanna landscape. However, the monitoring of rare tree species would require individual marking approaches due to their low densities and specific habitat requirements. Repeat sampling intervals would vary depending on the factor of concern and proposed management mitigation. Once a monitoring protocol has been identified and evaluated, the next stage is to

  2. Fire in Australian Savannas: from leaf to landscape

    NASA Astrophysics Data System (ADS)

    Beringer, J.; Hutley, L. B.; Tapper, N. J.; Cernusak, L. A.; Lynch, A. H.; Görgen, K.; Abramson, D.; Uotila, P.

    2009-04-01

    of carbon to the atmosphere because of the continued ecosystem respiration. We present data from 2001-2005 on the Net Biome Productivity of these savannas estimated at 2.0 tCha-1 yr-1 which is much greater than previously thought. Fire subsequently increased the Bowen ratio of the landscape and generated large increases in sensible heat fluxes. These changes in surface energy exchange following fire, when applied at the landscape scale, may have impacts on larger scale climate. At the local scale, enhanced sensible heat fluxes over patches of burnt landscape could generate mesoscale circulation systems (Knowles 1993). Variations in atmospheric heating rates above burnt and unburnt savanna and associated horizontal pressure gradients will produce atmospheric motion at a range of scales. In order to examine these processes we performed a sensitivity analysis using a global climate model (CSIRO Conformal-Cubic Atmospheric Model (C-CAM)). We utilized a distributed computing approach that allowed the development of a challenging experimental design that permitted simultaneous variation of all fire attributes (intensity, spatial extent and time during the year). The experiment demonstrates that savanna burning could shape the monsoon through two mechanisms. Boundary-layer circulation and large-scale convergence is intensified monotonically through increasing fire intensity and area burned. However, thresholds of fire timing and area are evident in the consequent influence on monsoon rainfall. In the optimal band of late, high intensity fires with a somewhat limited extent, it is possible for the wet season to be significantly enhanced. As such, these results suggest that local-to-regional scale circulation changes associated with burning may modify patterns of precipitation and could potentially affect the strength of the Australian monsoon as suggested by Beringer et al. (2003).

  3. Fire in Australian Savannas: from leaf to landscape

    NASA Astrophysics Data System (ADS)

    Beringer, J.

    2015-12-01

    Savanna ecosystems comprise 22% of the global terrestrial surface and 25% of Australia (almost 1.9 million km2) and provide significant ecosystem services through carbon and water cycles and the maintenance of biodiversity. The current structure, composition and distribution of Australian savannas have co-evolved with fire, yet remain driven by the dynamic constraints of their bioclimatic niche. Fire in Australian savannas influences both the biophysical and biogeochemical processes at multiple scales from leaf to landscape. Here we present the latest emission estimates from Australian savanna biomass burning and their contribution to global greenhouse gas budgets. We then review our understanding of the impacts of fire on ecosystem function and local surface water and heat balances, which in turn influence regional climate. We show how savanna fires are coupled to the global climate through the carbon cycle and fire regimes. We present new research that climate change is likely to alter the structure and function of savannas through shifts in moisture availability and increases in atmospheric carbon dioxide (CO2), in turn altering fire regimes with further feedbacks to climate. We explore opportunities to reduce net greenhouse gas emissions from savanna ecosystems through changes in savanna fire management.

  4. Fire in Australian savannas: from leaf to landscape

    PubMed Central

    Beringer, Jason; Hutley, Lindsay B; Abramson, David; Arndt, Stefan K; Briggs, Peter; Bristow, Mila; Canadell, Josep G; Cernusak, Lucas A; Eamus, Derek; Edwards, Andrew C; Evans, Bradley J; Fest, Benedikt; Goergen, Klaus; Grover, Samantha P; Hacker, Jorg; Haverd, Vanessa; Kanniah, Kasturi; Livesley, Stephen J; Lynch, Amanda; Maier, Stefan; Moore, Caitlin; Raupach, Michael; Russell-Smith, Jeremy; Scheiter, Simon; Tapper, Nigel J; Uotila, Petteri

    2015-01-01

    Savanna ecosystems comprise 22% of the global terrestrial surface and 25% of Australia (almost 1.9 million km2) and provide significant ecosystem services through carbon and water cycles and the maintenance of biodiversity. The current structure, composition and distribution of Australian savannas have coevolved with fire, yet remain driven by the dynamic constraints of their bioclimatic niche. Fire in Australian savannas influences both the biophysical and biogeochemical processes at multiple scales from leaf to landscape. Here, we present the latest emission estimates from Australian savanna biomass burning and their contribution to global greenhouse gas budgets. We then review our understanding of the impacts of fire on ecosystem function and local surface water and heat balances, which in turn influence regional climate. We show how savanna fires are coupled to the global climate through the carbon cycle and fire regimes. We present new research that climate change is likely to alter the structure and function of savannas through shifts in moisture availability and increases in atmospheric carbon dioxide, in turn altering fire regimes with further feedbacks to climate. We explore opportunities to reduce net greenhouse gas emissions from savanna ecosystems through changes in savanna fire management. PMID:25044767

  5. Fire in Australian savannas: from leaf to landscape.

    PubMed

    Beringer, Jason; Hutley, Lindsay B; Abramson, David; Arndt, Stefan K; Briggs, Peter; Bristow, Mila; Canadell, Josep G; Cernusak, Lucas A; Eamus, Derek; Edwards, Andrew C; Evans, Bradley J; Fest, Benedikt; Goergen, Klaus; Grover, Samantha P; Hacker, Jorg; Haverd, Vanessa; Kanniah, Kasturi; Livesley, Stephen J; Lynch, Amanda; Maier, Stefan; Moore, Caitlin; Raupach, Michael; Russell-Smith, Jeremy; Scheiter, Simon; Tapper, Nigel J; Uotila, Petteri

    2015-01-01

    Savanna ecosystems comprise 22% of the global terrestrial surface and 25% of Australia (almost 1.9 million km2) and provide significant ecosystem services through carbon and water cycles and the maintenance of biodiversity. The current structure, composition and distribution of Australian savannas have coevolved with fire, yet remain driven by the dynamic constraints of their bioclimatic niche. Fire in Australian savannas influences both the biophysical and biogeochemical processes at multiple scales from leaf to landscape. Here, we present the latest emission estimates from Australian savanna biomass burning and their contribution to global greenhouse gas budgets. We then review our understanding of the impacts of fire on ecosystem function and local surface water and heat balances, which in turn influence regional climate. We show how savanna fires are coupled to the global climate through the carbon cycle and fire regimes. We present new research that climate change is likely to alter the structure and function of savannas through shifts in moisture availability and increases in atmospheric carbon dioxide, in turn altering fire regimes with further feedbacks to climate. We explore opportunities to reduce net greenhouse gas emissions from savanna ecosystems through changes in savanna fire management. © 2014 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

  6. A spatio-temporal analysis of landscape dynamics under changing environmental regimes in southern African savannas

    NASA Astrophysics Data System (ADS)

    Bunting, Erin L.

    The United Nations and Intergovernmental Panel on Climate Change (IPCC) deem many regions of southern Africa as vulnerable landscapes due to changing climatic regimes, ecological condition, and low adaptive capacity. The savanna ecosystems of southern Africa are of great ecological importance due to the high biodiversity they sustain, their high level of productivity, and the great role they play in the global carbon cycle. Given the dependence of humans on the lands it is essential to explore landscape level trends in patterns and processes in an effort to inform management practices. Even if climate change mitigation strategies were put in place, this is still a region heavily dependent on rain-fed agriculture and tourism of the biological diverse lands. Therefore analysis of climate variability, both interannual and intra-annual, and the changing role it plays on the landscape is critical. This body of research analyzes the role of climate variability and climate on environmental condition and socio-economic development via research on (1) spatial and temporal vegetation patterns, (2) the underlying processes that influence savanna ecosystem resilience, (3) local perception of risk to livelihood development, and (4) potential consequences of climate change on vegetation patterns. As a whole this demonstrates the key role that climate plays on savanna landscapes, which would be highly beneficial when developing conservation or mitigation strategies. Increased climate variability is occurring, but what is still open to debate is the resilience of savanna landscape and vulnerability of socio-economic development.

  7. Disentangling how landscape spatial and temporal heterogeneity affects Savanna birds.

    PubMed

    Price, Bronwyn; McAlpine, Clive A; Kutt, Alex S; Ward, Doug; Phinn, Stuart R; Ludwig, John A

    2013-01-01

    In highly seasonal tropical environments, temporal changes in habitat and resources are a significant determinant of the spatial distribution of species. This study disentangles the effects of spatial and mid to long-term temporal heterogeneity in habitat on the diversity and abundance of savanna birds by testing four competing conceptual models of varying complexity. Focussing on sites in northeast Australia over a 20 year time period, we used ground cover and foliage projected cover surfaces derived from a time series of Landsat Thematic Mapper imagery, rainfall data and site-level vegetation surveys to derive measures of habitat structure at local (1-100 ha) and landscape (100-1000s ha) scales. We used generalised linear models and an information theoretic approach to test the independent effects of spatial and temporal influences on savanna bird diversity and the abundance of eight species with different life-history behaviours. Of four competing models defining influences on assemblages of savanna birds, the most parsimonious included temporal and spatial variability in vegetation cover and site-scale vegetation structure, suggesting savanna bird species respond to spatial and temporal habitat heterogeneity at both the broader landscape scale and at the fine-scale. The relative weight, strength and direction of the explanatory variables changed with each of the eight species, reflecting their different ecology and behavioural traits. This study demonstrates that variations in the spatial pattern of savanna vegetation over periods of 10 to 20 years at the local and landscape scale strongly affect bird diversity and abundance. Thus, it is essential to monitor and manage both spatial and temporal variability in avian habitat to achieve long-term biodiversity outcomes.

  8. Disentangling How Landscape Spatial and Temporal Heterogeneity Affects Savanna Birds

    PubMed Central

    Price, Bronwyn; McAlpine, Clive A.; Kutt, Alex S.; Ward, Doug; Phinn, Stuart R.; Ludwig, John A.

    2013-01-01

    In highly seasonal tropical environments, temporal changes in habitat and resources are a significant determinant of the spatial distribution of species. This study disentangles the effects of spatial and mid to long-term temporal heterogeneity in habitat on the diversity and abundance of savanna birds by testing four competing conceptual models of varying complexity. Focussing on sites in northeast Australia over a 20 year time period, we used ground cover and foliage projected cover surfaces derived from a time series of Landsat Thematic Mapper imagery, rainfall data and site-level vegetation surveys to derive measures of habitat structure at local (1–100 ha) and landscape (100–1000s ha) scales. We used generalised linear models and an information theoretic approach to test the independent effects of spatial and temporal influences on savanna bird diversity and the abundance of eight species with different life-history behaviours. Of four competing models defining influences on assemblages of savanna birds, the most parsimonious included temporal and spatial variability in vegetation cover and site-scale vegetation structure, suggesting savanna bird species respond to spatial and temporal habitat heterogeneity at both the broader landscape scale and at the fine-scale. The relative weight, strength and direction of the explanatory variables changed with each of the eight species, reflecting their different ecology and behavioural traits. This study demonstrates that variations in the spatial pattern of savanna vegetation over periods of 10 to 20 years at the local and landscape scale strongly affect bird diversity and abundance. Thus, it is essential to monitor and manage both spatial and temporal variability in avian habitat to achieve long-term biodiversity outcomes. PMID:24066138

  9. Microbial properties and litter and soil nutrients after two prescribed fires in developing savannas in an upland Missouri Ozark Forest

    Treesearch

    Felix, Jr. Ponder; Mahasin Tadros; Edward F. Loewenstein

    2009-01-01

    On some landscapes periodic fire may be necessary to develop and maintain oak-dominated savannas. We studied the effects of two annual prescribed burns to determine their effect on microbial activity and soil and litter nutrients 1 year after the last burn. Surface litter and soil from the upper 0?5 cm soil layer in three developing savannas (oak-hickory, ...

  10. Climate and the landscape of fear in an African savanna.

    PubMed

    Riginos, Corinna

    2015-01-01

    Herbivores frequently have to make trade-offs between two basic needs: the need to acquire forage and the need to avoid predation. One manifestation of this trade-off is the 'landscape of fear' phenomenon - wherein herbivores avoid areas of high perceived predation risk even if forage is abundant or of high quality in those areas. Although this phenomenon is well established among invertebrates, its applicability to terrestrial large herbivores remains debated, in part because experimental evidence is scarce. This study was designed to (i) experimentally test the effects of tree density - a key landscape feature associated with predation risk for African ungulates - on herbivore habitat use and (ii) establish whether habitat use patterns could be explained by trade-offs between foraging opportunities and predation risk avoidance. In a Kenyan savanna system, replicate plots dominated by the tree Acacia drepanolobium were cleared, thinned or left intact. Ungulate responses were measured over four years, which included years of moderate rainfall as well as a severe drought. Under average rainfall conditions, most herbivores (primarily plains zebra, Grant's gazelle and hartebeest) favoured sites with fewer trees and higher visibility - regardless of grass production - while elephants (too large to be vulnerable to predation) favoured sites with many trees. During the drought, however, herbivores favoured sites that had high grass biomass, but not high visibility. Thus, during the drought, herbivores sought areas where food was more abundant, despite probable higher risk of predation. These results illustrate that the 'landscape of fear', and the associated interactions between top-down and bottom-up effects, is not static, but rather shifts markedly under different conditions. Climate thus has the potential to alter the strength and spatial dynamics of behaviourally mediated cascades in large herbivore systems.

  11. Opposing resonses to ecological gradients structure amphibian and reptile communities across a temperate grassland-savanna-forest landscape

    USGS Publications Warehouse

    Grundel, Ralph; Beamer, David; Glowacki, Gary A.; Frohnapple, Krystal; Pavlovic, Noel B.

    2014-01-01

    Temperate savannas are threatened across the globe. If we prioritize savanna restoration, we should ask how savanna animal communities differ from communities in related open habitats and forests. We documented distribution of amphibian and reptile species across an open-savanna–forest gradient in the Midwest U.S. to determine how fire history and habitat structure affected herpetofaunal community composition. The transition from open habitats to forests was a transition from higher reptile abundance to higher amphibian abundance and the intermediate savanna landscape supported the most species overall. These differences warn against assuming that amphibian and reptile communities will have similar ecological responses to habitat structure. Richness and abundance also often responded in opposite directions to some habitat characteristics, such as cover of bare ground or litter. Herpetofaunal community species composition changed along a fire gradient from infrequent and recent fires to frequent but less recent fires. Nearby (200-m) wetland cover was relatively unimportant in predicting overall herpetofaunal community composition while fire history and fire-related canopy and ground cover were more important predictors of composition, diversity, and abundance. Increased developed cover was negatively related to richness and abundance. This indicates the importance of fire history and fire related landscape characteristics, and the negative effects of development, in shaping the upland herpetofaunal community along the native grassland–forest continuum.

  12. Using conservation value to assess land restoration and management alternatives across a degraded oak savanna landscape

    USGS Publications Warehouse

    Grundel, R.; Pavlovic, N.B.

    2008-01-01

    1. Managers considering restoration of landscapes often face a fundamental challenge - what should be the habitat composition of the restored landscape? We present a method for evaluating an important conservation trade-off inherent in making that decision. 2. Oak savannas and grasslands were historically widespread across central North America but are now rare. Today, in north-west Indiana, USA, habitats spanning a range of woody vegetation density, from nearly treeless open habitats to forests, occur across the conserved landscape where savannas probably once dominated. To understand the benefits of different potential landscape compositions, we evaluated how different proportions of five habitats - open, savanna, woodland, scrub and forest - might affect the conservation value of the north-west Indiana landscape for birds. Two variables of potential conservation importance were examined: species diversity, a measure of avian community richness, and conservation index, the percentage of a bird species' global population occurring on a hectare of landscape, summed across all bird species present. Higher values of conservation index were associated with higher local densities of globally more rare and more threatened species. 3. Conservation index and species diversity were correlated negatively across hypothetical landscapes composed of different proportions of the five habitats. Therefore, a management trade-off existed between conservation index and species diversity because landscapes that maximized species diversity differed from landscapes that maximized conservation index. 4. A landscape of 50% open, 22% savanna, 15% scrub and 13% forest was predicted to represent a compromise at which conservation index and species diversity reached the same percentage of their maxima. In contrast, the current landscape is dominated by forest. 5. Synthesis and applications. We quantified the trade-off between two potential aspects of a landscape's conservation value for

  13. Local versus landscape-scale effects of savanna trees on grasses

    USGS Publications Warehouse

    Riginos, C.; Grace, J.B.; Augustine, D.J.; Young, T.P.

    2009-01-01

    1. Savanna ecosystems - defined by the coexistence of trees and grasses - cover more than one-fifth the world's land surface and harbour most of the world's rangelands, livestock and large mammal diversity. Savanna trees can have a variety of effects on grasses, with consequences for the wild and domestic herbivores that depend on them. 2.Studies of these effects have focused on two different spatial scales. At the scale of individual trees, many studies have shown net positive effects of trees on sub-canopy grass nutrient concentrations and biomass. At the landscape scale, other studies have shown negative effects of high tree densities on grass productivity. These disparate results have led to different conclusions about the effects of trees on forage quality and ungulate nutrition in savannas. 3.We integrate these approaches by examining the effects of trees on grasses at both spatial scales and across a range of landscape-scale tree densities. 4.We quantified grass biomass, species composition and nutrient concentrations in these different contexts in an Acacia drepanolobium savanna in Laikipia, Kenya. Individual trees had positive effects on grass biomass, most likely because trees enrich soil nitrogen. Grass leaf phosphorus in sub-canopy areas, however, was depressed. The effects of individual trees could explain the effects of increasing landscape-scale tree cover for the biomass of only two of the four dominant grass species. 5.The negative effects of trees on grass and soil phosphorus, combined with depressed grass productivity in areas of high tree cover, suggest that ungulate nutrition may be compromised in areas with many trees. 6.Synthesis. We conclude that few, isolated trees may have positive local effects on savanna grasses and forage, but in areas of high tree density the negative landscape-scale effects of trees are likely to outweigh these positive effects. In savannas and other patchy landscapes, attempts to predict the consequences of changes

  14. Relationships between bat occupancy and habitat and landscape structure along a savanna, woodland, forest gradient in the Missouri Ozarks

    Treesearch

    Clarissa A. Starbuck; Sybill K. Amelon; Frank R. III. Thompson

    2015-01-01

    Many land-management agencies are restoring savannas and woodlands using prescribed fire and forest thinning, and information is needed on how wildlife species respond to these management activities. Our objectives were to evaluate support for relationships of bat site occupancy with vegetation structure and management and landscape composition and structure across a...

  15. Seasonality of fire weather strongly influences fire regimes in South Florida savanna-grassland landscapes.

    PubMed

    Platt, William J; Orzell, Steve L; Slocum, Matthew G

    2015-01-01

    Fire seasonality, an important characteristic of fire regimes, commonly is delineated using seasons based on single weather variables (rainfall or temperature). We used nonparametric cluster analyses of a 17-year (1993-2009) data set of weather variables that influence likelihoods and spread of fires (relative humidity, air temperature, solar radiation, wind speed, soil moisture) to explore seasonality of fire in pine savanna-grassland landscapes at the Avon Park Air Force Range in southern Florida. A four-variable, three-season model explained more variation within fire weather variables than models with more seasons. The three-season model also delineated intra-annual timing of fire more accurately than a conventional rainfall-based two-season model. Two seasons coincided roughly with dry and wet seasons based on rainfall. The third season, which we labeled the fire season, occurred between dry and wet seasons and was characterized by fire-promoting conditions present annually: drought, intense solar radiation, low humidity, and warm air temperatures. Fine fuels consisting of variable combinations of pyrogenic pine needles, abundant C4 grasses, and flammable shrubs, coupled with low soil moisture, and lightning ignitions early in the fire season facilitate natural landscape-scale wildfires that burn uplands and across wetlands. We related our three season model to fires with different ignition sources (lightning, military missions, and prescribed fires) over a 13-year period with fire records (1997-2009). Largest wildfires originate from lightning and military ignitions that occur within the early fire season substantially prior to the peak of lightning strikes in the wet season. Prescribed ignitions, in contrast, largely occur outside the fire season. Our delineation of a pronounced fire season provides insight into the extent to which different human-derived fire regimes mimic lightning fire regimes. Delineation of a fire season associated with timing of

  16. Seasonality of Fire Weather Strongly Influences Fire Regimes in South Florida Savanna-Grassland Landscapes

    PubMed Central

    Platt, William J.; Orzell, Steve L.; Slocum, Matthew G.

    2015-01-01

    Fire seasonality, an important characteristic of fire regimes, commonly is delineated using seasons based on single weather variables (rainfall or temperature). We used nonparametric cluster analyses of a 17-year (1993–2009) data set of weather variables that influence likelihoods and spread of fires (relative humidity, air temperature, solar radiation, wind speed, soil moisture) to explore seasonality of fire in pine savanna-grassland landscapes at the Avon Park Air Force Range in southern Florida. A four-variable, three-season model explained more variation within fire weather variables than models with more seasons. The three-season model also delineated intra-annual timing of fire more accurately than a conventional rainfall-based two-season model. Two seasons coincided roughly with dry and wet seasons based on rainfall. The third season, which we labeled the fire season, occurred between dry and wet seasons and was characterized by fire-promoting conditions present annually: drought, intense solar radiation, low humidity, and warm air temperatures. Fine fuels consisting of variable combinations of pyrogenic pine needles, abundant C4 grasses, and flammable shrubs, coupled with low soil moisture, and lightning ignitions early in the fire season facilitate natural landscape-scale wildfires that burn uplands and across wetlands. We related our three season model to fires with different ignition sources (lightning, military missions, and prescribed fires) over a 13-year period with fire records (1997–2009). Largest wildfires originate from lightning and military ignitions that occur within the early fire season substantially prior to the peak of lightning strikes in the wet season. Prescribed ignitions, in contrast, largely occur outside the fire season. Our delineation of a pronounced fire season provides insight into the extent to which different human-derived fire regimes mimic lightning fire regimes. Delineation of a fire season associated with timing of

  17. Comparison of the driving forces of spring phenology among savanna landscapes by including combined spatial and temporal heterogeneity

    NASA Astrophysics Data System (ADS)

    Zhu, Likai; Southworth, Jane; Meng, Jijun

    2015-10-01

    Understanding spatial and temporal dynamics of land surface phenology (LSP) and its driving forces are critical for providing information relevant to short- and long-term decision making, particularly as it relates to climate response planning. With the third generation Global Inventory Monitoring and Modeling System (GIMMS3g) Normalized Difference Vegetation Index (NDVI) data and environmental data from multiple sources, we investigated the spatio-temporal changes in the start of the growing season (SOS) in southern African savannas from 1982 through 2010 and determined its linkage to environmental factors using spatial panel data models. Overall, the SOS occurs earlier in the north compared to the south. This relates in part to the differences in ecosystems, with northern areas representing high rainfall and dense tree cover (mainly tree savannas), whereas the south has lower rainfall and sparse tree cover (mainly bush and grass savannas). From 1982 to 2010, an advanced trend was observed predominantly in the tree savanna areas of the north, whereas a delayed trend was chiefly found in the floodplain of the north and bush/grass savannas of the south. Different environmental drivers were detected within tree- and grass-dominated savannas, with a critical division being represented by the 800 mm isohyet. Our results supported the importance of water as a driver in this water-limited system, specifically preseason soil moisture, in determining the SOS in these water-limited, grass-dominated savannas. In addition, the research pointed to other, often overlooked, effects of preseason maximum and minimum temperatures on the SOS across the entire region. Higher preseason maximum temperatures led to an advance of the SOS, whereas the opposite effects of preseason minimum temperature were observed. With the rapid increase in global change research, this work will prove helpful for managing savanna landscapes and key to predicting how projected climate changes will affect

  18. Comparison of the driving forces of spring phenology among savanna landscapes by including combined spatial and temporal heterogeneity.

    PubMed

    Zhu, Likai; Southworth, Jane; Meng, Jijun

    2015-10-01

    Understanding spatial and temporal dynamics of land surface phenology (LSP) and its driving forces are critical for providing information relevant to short- and long-term decision making, particularly as it relates to climate response planning. With the third generation Global Inventory Monitoring and Modeling System (GIMMS3g) Normalized Difference Vegetation Index (NDVI) data and environmental data from multiple sources, we investigated the spatio-temporal changes in the start of the growing season (SOS) in southern African savannas from 1982 through 2010 and determined its linkage to environmental factors using spatial panel data models. Overall, the SOS occurs earlier in the north compared to the south. This relates in part to the differences in ecosystems, with northern areas representing high rainfall and dense tree cover (mainly tree savannas), whereas the south has lower rainfall and sparse tree cover (mainly bush and grass savannas). From 1982 to 2010, an advanced trend was observed predominantly in the tree savanna areas of the north, whereas a delayed trend was chiefly found in the floodplain of the north and bush/grass savannas of the south. Different environmental drivers were detected within tree- and grass-dominated savannas, with a critical division being represented by the 800 mm isohyet. Our results supported the importance of water as a driver in this water-limited system, specifically preseason soil moisture, in determining the SOS in these water-limited, grass-dominated savannas. In addition, the research pointed to other, often overlooked, effects of preseason maximum and minimum temperatures on the SOS across the entire region. Higher preseason maximum temperatures led to an advance of the SOS, whereas the opposite effects of preseason minimum temperature were observed. With the rapid increase in global change research, this work will prove helpful for managing savanna landscapes and key to predicting how projected climate changes will affect

  19. Monitoring Contrasting Land Management in the Savanna Landscapes of Northern Australia

    NASA Astrophysics Data System (ADS)

    Franklin, Donald C.; Petty, Aaron M.; Williamson, Grant J.; Brook, Barry W.; Bowman, David M. J. S.

    2008-04-01

    We compared measures of ecosystem state across six adjacent land-tenure groups in the intact tropical savanna landscapes of northern Australia. Tenure groups include two managed by Aboriginal owners, two national parks, a cluster of pastoral leases, and a military training area. This information is of relevance to the debate about the role of indigenous lands in the Australian conservation estate. The timing and frequency of fire was determined by satellite imagery; the biomass and composition of the herb-layer and the abundance of large feral herbivores by field surveys; and weediness by analysis of a Herbarium database. European tenures varied greatly in fire frequencies but were consistently burnt earlier in the dry season than the two Aboriginal tenures, the latter having intermediate fire frequencies. Weeds were more frequent in the European tenures, whilst feral animals were most abundant in the Aboriginal tenures. This variation strongly implies a signature of current management and/or recent environmental history. We identify indices suitable for monitoring of management outcomes in an extensive and sparsely populated landscape. Aboriginal land offers a unique opportunity for the conservation of biodiversity through the maintenance of traditional fire regimes. However, without financial support, traditional practices may prove unsustainable both economically and because exotic weeds and feral animals will alter fire regimes. An additional return on investment in Aboriginal land management is likely to be improved livelihoods and health outcomes for these disadvantaged communities.

  20. Monitoring contrasting land management in the savanna landscapes of northern Australia.

    PubMed

    Franklin, Donald C; Petty, Aaron M; Williamson, Grant J; Brook, Barry W; Bowman, David M J S

    2008-04-01

    We compared measures of ecosystem state across six adjacent land-tenure groups in the intact tropical savanna landscapes of northern Australia. Tenure groups include two managed by Aboriginal owners, two national parks, a cluster of pastoral leases, and a military training area. This information is of relevance to the debate about the role of indigenous lands in the Australian conservation estate. The timing and frequency of fire was determined by satellite imagery; the biomass and composition of the herb-layer and the abundance of large feral herbivores by field surveys; and weediness by analysis of a Herbarium database. European tenures varied greatly in fire frequencies but were consistently burnt earlier in the dry season than the two Aboriginal tenures, the latter having intermediate fire frequencies. Weeds were more frequent in the European tenures, whilst feral animals were most abundant in the Aboriginal tenures. This variation strongly implies a signature of current management and/or recent environmental history. We identify indices suitable for monitoring of management outcomes in an extensive and sparsely populated landscape. Aboriginal land offers a unique opportunity for the conservation of biodiversity through the maintenance of traditional fire regimes. However, without financial support, traditional practices may prove unsustainable both economically and because exotic weeds and feral animals will alter fire regimes. An additional return on investment in Aboriginal land management is likely to be improved livelihoods and health outcomes for these disadvantaged communities.

  1. A multi-scale spatial analysis of native and exotic plant species richness within a mixed-disturbance oak savanna landscape.

    PubMed

    Schetter, Timothy A; Walters, Timothy L; Root, Karen V

    2013-09-01

    Impacts of human land use pose an increasing threat to global biodiversity. Resource managers must respond rapidly to this threat by assessing existing natural areas and prioritizing conservation actions across multiple spatial scales. Plant species richness is a useful measure of biodiversity but typically can only be evaluated on small portions of a given landscape. Modeling relationships between spatial heterogeneity and species richness may allow conservation planners to make predictions of species richness patterns within unsampled areas. We utilized a combination of field data, remotely sensed data, and landscape pattern metrics to develop models of native and exotic plant species richness at two spatial extents (60- and 120-m windows) and at four ecological levels for northwestern Ohio's Oak Openings region. Multiple regression models explained 37-77 % of the variation in plant species richness. These models consistently explained more variation in exotic richness than in native richness. Exotic richness was better explained at the 120-m extent while native richness was better explained at the 60-m extent. Land cover composition of the surrounding landscape was an important component of all models. We found that percentage of human-modified land cover (negatively correlated with native richness and positively correlated with exotic richness) was a particularly useful predictor of plant species richness and that human-caused disturbances exert a strong influence on species richness patterns within a mixed-disturbance oak savanna landscape. Our results emphasize the importance of using a multi-scale approach to examine the complex relationships between spatial heterogeneity and plant species richness.

  2. 23 CFR 752.4 - Landscape development.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 23 Highways 1 2011-04-01 2011-04-01 false Landscape development. 752.4 Section 752.4 Highways... ROADSIDE DEVELOPMENT § 752.4 Landscape development. (a) Landscape development, which includes landscaping... landscaping and environmental design. (b) Landscape development should have provisions for plant establishment...

  3. 23 CFR 752.4 - Landscape development.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 23 Highways 1 2012-04-01 2012-04-01 false Landscape development. 752.4 Section 752.4 Highways... ROADSIDE DEVELOPMENT § 752.4 Landscape development. (a) Landscape development, which includes landscaping... landscaping and environmental design. (b) Landscape development should have provisions for plant establishment...

  4. 23 CFR 752.4 - Landscape development.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 23 Highways 1 2014-04-01 2014-04-01 false Landscape development. 752.4 Section 752.4 Highways... ROADSIDE DEVELOPMENT § 752.4 Landscape development. (a) Landscape development, which includes landscaping... landscaping and environmental design. (b) Landscape development should have provisions for plant establishment...

  5. 23 CFR 752.4 - Landscape development.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Landscape development. 752.4 Section 752.4 Highways... ROADSIDE DEVELOPMENT § 752.4 Landscape development. (a) Landscape development, which includes landscaping... landscaping and environmental design. (b) Landscape development should have provisions for plant establishment...

  6. 23 CFR 752.4 - Landscape development.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 23 Highways 1 2013-04-01 2013-04-01 false Landscape development. 752.4 Section 752.4 Highways... ROADSIDE DEVELOPMENT § 752.4 Landscape development. (a) Landscape development, which includes landscaping... landscaping and environmental design. (b) Landscape development should have provisions for plant establishment...

  7. Spatial Patterns of Plant δ13C and δ15N Along a Topoedaphic Gradient in a Subtropical Savanna Landscape

    NASA Astrophysics Data System (ADS)

    Bai, E.; Boutton, T. W.; Liu, F.; Wu, B.; Archer, S. R.

    2005-12-01

    δ13C and δ15N values of plants are powerful tools in physiological ecology, ecosystem science, and global biogeochemistry, yet we know relatively little about their variation and controls at the landscape scale. In this study, we investigated landscape-scale spatial variations in the foliar isotopic composition of 3 woody plant species across a 308 m topoedaphic gradient, along which soil texture and plant resources (water and nitrogen availability) varied from upland (86 m) to lowland (84 m) portions of the landscape. The study was conducted in a subtropical savanna at the La Copita Research Area, approximately 60 km west of Corpus Christi, TX. Foliar δ13C, δ15N, leaf nitrogen concentration ([N]), and specific leaf area (SLA) were measured on all individuals of Prosopis glandulosa, Condalia hookeri, and Zanthoxylum fagara present within a belt transect 308 m long x 12 m wide. Soil texture, available soil moisture, and total N were measured at 1 m intervals along the center-line of the belt transect. Clay content, available soil moisture, and soil total N were all negatively correlated with elevation along the transect. Leaf δ13C and δ15N values for all 3 species increased by 1-4 o/oo with decreasing elevation along the transect. Contrary to theory and previous studies, δ13C values were highest where soil water was most available, suggesting that some other variable could be overriding or interacting with water availability. Foliar [N] appeared to exert the strongest control over landscape-level variation, and was positively correlated with δ13C of all species (R 2 = 0.58, p<0.0001). Since leaf [N] is positively related to photosynthetic capacity, plants with high [N] are likely to have low Ci/Ca ratios and therefore higher δ13C values. δ15N values of Zanthoxylum and Condalia were positively correlated with leaf [N] and soil water availability; however, these relationships were absent for Prosopis, an N-fixing tree legume. We speculate that the

  8. Elephant movement closely tracks precipitation-driven vegetation dynamics in a Kenyan forest-savanna landscape.

    PubMed

    Bohrer, Gil; Beck, Pieter Sa; Ngene, Shadrack M; Skidmore, Andrew K; Douglas-Hamilton, Ian

    2014-01-01

    This study investigates the ranging behavior of elephants in relation to precipitation-driven dynamics of vegetation. Movement data were acquired for five bachelors and five female family herds during three years in the Marsabit protected area in Kenya and changes in vegetation were mapped using MODIS normalized difference vegetation index time series (NDVI). In the study area, elevations of 650 to 1100 m.a.s.l experience two growth periods per year, while above 1100 m.a.s.l. growth periods last a year or longer. We find that elephants respond quickly to changes in forage and water availability, making migrations in response to both large and small rainfall events. The elevational migration of individual elephants closely matched the patterns of greening and senescing of vegetation in their home range. Elephants occupied lower elevations when vegetation activity was high, whereas they retreated to the evergreen forest at higher elevations while vegetation senesced. Elephant home ranges decreased in size, and overlapped less with increasing elevation. A recent hypothesis that ungulate migrations in savannas result from countervailing seasonally driven rainfall and fertility gradients is demonstrated, and extended to shorter-distance migrations. In other words, the trade-off between the poor forage quality and accessibility in the forest with its year-round water sources on the one hand and the higher quality forage in the low-elevation scrubland with its seasonal availability of water on the other hand, drives the relatively short migrations (the two main corridors are 20 and 90 km) of the elephants. In addition, increased intra-specific competition appears to influence the animals' habitat use during the dry season indicating that the human encroachment on the forest is affecting the elephant population.

  9. Burning, fire prevention and landscape productions among the Pemon, Gran Sabana, Venezuela: toward an intercultural approach to wildland fire management in Neotropical Savannas.

    PubMed

    Sletto, Bjørn; Rodriguez, Iokiñe

    2013-01-30

    Wildland fire management in savanna landscapes increasingly incorporates indigenous knowledge to pursue strategies of controlled, prescriptive burning to control fuel loads. However, such participatory approaches are fraught with challenges because of contrasting views on the role of fire and the practices of prescribed burning between indigenous and state fire managers. Also, indigenous and state systems of knowledge and meanings associated with fire are not monolithic but instead characterized by conflicts and inconsistencies, which require new, communicative strategies in order to develop successful, intercultural approaches to fire management. This paper is based on long-term research on indigenous Pemon social constructs, rules and regulations regarding fire use, and traditional system of prescribed burning in the Gran Sabana, Venezuela. The authors review factors that act as constraints against successful intercultural fire management in the Gran Sabana, including conflicting perspectives on fire use within state agencies and in indigenous communities, and propose strategies for research and communicative planning to guide future efforts for more participatory and effective fire management. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Landscape changes in a neotropical forest-savanna ecotone zone in central Brazil: The role of protected areas in the maintenance of native vegetation.

    PubMed

    Garcia, Andrea S; Sawakuchi, Henrique O; Ferreira, Manuel Eduardo; Ballester, Maria Victoria R

    2017-02-01

    In the Amazon-savanna ecotone in northwest Brazil, the understudied Araguaia River Basin contains high biodiversity and seasonal wetlands. The region is representative of tropical humid-dry ecotone zones, which have experienced intense land use and land cover (LULC) conversions. Here we assessed the LULC changes for the last four decades in the central portion of the Araguaia River Basin to understand the temporal changes in the landscape composition and configuration outside and inside protected areas. We conducted these analyzes by LULC mapping and landscape metrics based on patch classes. During this period, native vegetation was reduced by 26%. Forests were the most threatened physiognomy, with significant areal reduction and fragmentation. Native vegetation cover was mainly replaced by croplands and pastures. Such replacement followed spatial and temporal trends related to the implementation of protected areas and increases in population cattle herds. The creation of most protected areas took place between 1996 and 2007, the same period during which the conversion of the landscape matrix from natural vegetation to agriculture occurred. We observed that protected areas mitigate fragmentation, but their roles differ according to their location and level of protection. Still, we argue that landscape characteristics, such as suitability for agriculture, also influence landscape conversions and should be considered when establishing protected areas. The information provided in this study can guide new research on species conservation and landscape planning, as well as improve the understanding of the impacts of landscape composition and configuration changes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. [Landscape classification: research progress and development trend].

    PubMed

    Liang, Fa-Chao; Liu, Li-Ming

    2011-06-01

    Landscape classification is the basis of the researches on landscape structure, process, and function, and also, the prerequisite for landscape evaluation, planning, protection, and management, directly affecting the precision and practicability of landscape research. This paper reviewed the research progress on the landscape classification system, theory, and methodology, and summarized the key problems and deficiencies of current researches. Some major landscape classification systems, e. g. , LANMAP and MUFIC, were introduced and discussed. It was suggested that a qualitative and quantitative comprehensive classification based on the ideology of functional structure shape and on the integral consideration of landscape classification utility, landscape function, landscape structure, physiogeographical factors, and human disturbance intensity should be the major research directions in the future. The integration of mapping, 3S technology, quantitative mathematics modeling, computer artificial intelligence, and professional knowledge to enhance the precision of landscape classification would be the key issues and the development trend in the researches of landscape classification.

  12. Breeding bird response to habitat and landscape factors across a gradient of savanna, woodland, and forest in the Missouri Ozarks

    Treesearch

    Jennifer L. Reidy; Frank R. Thompson; Sarah W. Kendrick

    2014-01-01

    Savanna and woodland were once common in the Midwest, but land use changes have led to increasing scarcity of these communities. These transitional habitats are being restored across the Midwest, but few studies have evaluated the response of wildlife to restoration or the vegetative gradient created by management. We conducted point counts for 25 songbirds at sites...

  13. Development of grasslands and savannas in East Africa during the Neogene

    NASA Astrophysics Data System (ADS)

    Serling, T. E.

    1992-03-01

    The development of savanna-type grasslands is a relatively recent phenomena in East Africa. The stable carbon isotopic composition of paleosol carbonates from fossil localities in East Africa show that C 4 vegetation was present by amout 8-9 Ma but made up only a relatively small proportion of the total biomass. Although the proportion of C 4 vegetation increased in the Pliocene and Pleistocene there is no evidence for the development of virtually pure C 4 grasslands, as is characterized by tropical grasslands today, until Middle Pleistocene times. This has important implications concerning the evolution of mammals in Africa, including hominids.

  14. A Landscape-Scale, Applied Fire Management Experiment Promotes Recovery of a Population of the Threatened Gouldian Finch, Erythrura gouldiae, in Australia's Tropical Savannas.

    PubMed

    Legge, Sarah; Garnett, Stephen; Maute, Kim; Heathcote, Joanne; Murphy, Steve; Woinarski, John C Z; Astheimer, Lee

    2015-01-01

    Fire is an integral part of savanna ecology and changes in fire patterns are linked to biodiversity loss in savannas worldwide. In Australia, changed fire regimes are implicated in the contemporary declines of small mammals, riparian species, obligate-seeding plants and grass seed-eating birds. Translating this knowledge into management to recover threatened species has proved elusive. We report here on a landscape-scale experiment carried out by the Australian Wildlife Conservancy (AWC) on Mornington Wildlife Sanctuary in northwest Australia. The experiment was designed to understand the response of a key savanna bird guild to fire, and to use that information to manage fire with the aim of recovering a threatened species population. We compared condition indices among three seed-eating bird species--one endangered (Gouldian finch) and two non-threatened (long-tailed finch and double-barred finch)--from two large areas (> 2,830 km2) with initial contrasting fire regimes ('extreme': frequent, extensive, intense fire; versus 'benign': less frequent, smaller, lower intensity fires). Populations of all three species living with the extreme fire regime had condition indices that differed from their counterparts living with the benign fire regime, including higher haematocrit levels in some seasons (suggesting higher levels of activity required to find food), different seasonal haematocrit profiles, higher fat scores in the early wet season (suggesting greater food uncertainty), and then lower muscle scores later in the wet season (suggesting prolonged food deprivation). Gouldian finches also showed seasonally increasing stress hormone concentrations with the extreme fire regime. Cumulatively, these patterns indicated greater nutritional stress over many months for seed-eating birds exposed to extreme fire regimes. We tested these relationships by monitoring finch condition over the following years, as AWC implemented fire management to produce the 'benign' fire regime

  15. A Landscape-Scale, Applied Fire Management Experiment Promotes Recovery of a Population of the Threatened Gouldian Finch, Erythrura gouldiae, in Australia’s Tropical Savannas

    PubMed Central

    Legge, Sarah; Garnett, Stephen; Maute, Kim; Heathcote, Joanne; Murphy, Steve; Woinarski, John C. Z.; Astheimer, Lee

    2015-01-01

    Fire is an integral part of savanna ecology and changes in fire patterns are linked to biodiversity loss in savannas worldwide. In Australia, changed fire regimes are implicated in the contemporary declines of small mammals, riparian species, obligate-seeding plants and grass seed-eating birds. Translating this knowledge into management to recover threatened species has proved elusive. We report here on a landscape-scale experiment carried out by the Australian Wildlife Conservancy (AWC) on Mornington Wildlife Sanctuary in northwest Australia. The experiment was designed to understand the response of a key savanna bird guild to fire, and to use that information to manage fire with the aim of recovering a threatened species population. We compared condition indices among three seed-eating bird species–one endangered (Gouldian finch) and two non-threatened (long-tailed finch and double-barred finch)—from two large areas (> 2,830 km2) with initial contrasting fire regimes (‘extreme’: frequent, extensive, intense fire; versus ‘benign’: less frequent, smaller, lower intensity fires). Populations of all three species living with the extreme fire regime had condition indices that differed from their counterparts living with the benign fire regime, including higher haematocrit levels in some seasons (suggesting higher levels of activity required to find food), different seasonal haematocrit profiles, higher fat scores in the early wet season (suggesting greater food uncertainty), and then lower muscle scores later in the wet season (suggesting prolonged food deprivation). Gouldian finches also showed seasonally increasing stress hormone concentrations with the extreme fire regime. Cumulatively, these patterns indicated greater nutritional stress over many months for seed-eating birds exposed to extreme fire regimes. We tested these relationships by monitoring finch condition over the following years, as AWC implemented fire management to produce the

  16. Variations in net CO2 flux across a tropical savanna landscape due to spatial variations in hydrology and land use

    NASA Astrophysics Data System (ADS)

    Arruda, P. H. Z. D.; Vourlitis, G. L.; Santanna, F. B.; Lobo, F. D. A., Sr.; Nogueira, J. D. S.; Pinto-Jr, O. B.

    2016-12-01

    The savanna vegetation of Brazil (Cerrado) accounts for 20-25% of the land cover of Brazil; however, large spatial variations in vegetation type, hydrology, and land use presumably result in large spatial and temporal variations in ecosystem mass and energy exchange. We used eddy covariance to measure the net ecosystem CO2 exchange (NEE) of grass-dominated Cerrado (campo sujo) over three years and partitioned the flux footprint into three sectors that varied with respect to seasonal hydrology (flooded vs. upland) and land use (mowed vs. unmowed). We hypothesized that spatial variations in hydrology and land use would cause spatial variations in the direction and magnitude of net ecosystem CO2 exchange (NEE). Average daily NEE during the wet season for the flooded and unmowed upland sectors ranged between -0.75- -3.25 umol m-2 s-1, while NEE fluxes for the mowed sector ranged between -0.60- +1.50 umol m-2 s-1 (negative values indicate net ecosystem CO2 uptake). Thus, over the 3 year study period the mowed sector was a not source of CO2 to the atmosphere while the flooded and upland sectors were net CO2 sinks during the wet season. In contrast, both upland and flooded sectors were net sources of CO2 to the atmosphere during the dry season while the mowed sector was approximately in balance. Mowing savanna grasses during the dry season caused net daytime NEE (a proxy for net photosynthesis) to increase significantly compared to the flooded and upland surfaces; however, mowed areas had lower daytime NEE during the wet season compared to the other sectors. Nighttime rates of NEE (a proxy for ecosystem respiration) were similar for all sectors regardless of season and land use. Thus, differences in NEE due to seasonal variations in hydrology and land use acted to alter photosynthetic C gain rather than respiration. Our results indicate that the NEE of grass-dominated Cerrado is very sensitive to land management practices that alter leaf area index and photosynthetic C

  17. Deciphering the distribution of the savanna biome.

    PubMed

    Lehmann, Caroline E R; Archibald, Sally A; Hoffmann, William A; Bond, William J

    2011-07-01

    • We aimed to identify the limits of savanna across Africa, Australia and South America. We based our investigation on the rich history of hypotheses previously examined: that the limits of savanna are variously determined by rainfall, rainfall seasonality, soil fertility and disturbance. • We categorized vegetation on all continents as 'savanna' (open habitats with a C(4) grass layer) or 'not-savanna' (closed habitats with no C(4) grass layer) and used a combination of statistical approaches to examine how the presence of savanna varied as a function of five environmental correlates. • The presence of savanna is constrained by effective rainfall and rainfall seasonality. Soil fertility is regionally important, although the direction of its effect changes relative to rainfall. We identified three continental divergences in the limits of savanna that could not be explained by environment. • Climate and soils do not have a deterministic effect on the distribution of savanna. Over the range of savanna, some proportion of the land is always 'not-savanna'. We reconciled previous contradictory views of savanna limits by developing a new conceptual framework for understanding these limits by categorizing environmental factors into whether they had a positive or negative effect on woody growth and the frequency of disturbance.

  18. Linking remotely sensed forage quality estimates from WorldView-2 multispectral data with cattle distribution in a savanna landscape

    NASA Astrophysics Data System (ADS)

    Zengeya, Fadzai M.; Mutanga, Onisimo; Murwira, Amon

    2013-04-01

    Remote sensing has recently been used to map forage quality for rangeland management. However, the validity of the remotely sensed forage quality can best be assessed when it connects well with the animal unit. In this study we used the new WorldView-2 multispectral imagery to estimate and map forage quality (nitrogen concentration) as a step to explain GPS based cattle distribution in a rangeland of Southeastern Zimbabwe. Nitrogen concentration was successfully estimated and mapped (Rcv2 = 0.66, relative error = 0.13%) using partial least squares regression (PLSR). The integration of GPS based cattle distribution patterns with forage quality in a GIS showed that cattle locations significantly clustered in areas of high forage quality. The results of this study suggest that new multispectral data with unique band settings such as WorldView-2 improves the estimation and mapping of forage quality in rangelands at landscape level. In addition, our results indicate that remotely sensed forage quality can be used to explain herbivore distribution, particularly cattle grazing patterns in rangelands.

  19. Vocal development in a Waddington landscape

    PubMed Central

    Teramoto, Yayoi; Takahashi, Daniel Y; Holmes, Philip; Ghazanfar, Asif A

    2017-01-01

    Vocal development is the adaptive coordination of the vocal apparatus, muscles, the nervous system, and social interaction. Here, we use a quantitative framework based on optimal control theory and Waddington’s landscape metaphor to provide an integrated view of this process. With a biomechanical model of the marmoset monkey vocal apparatus and behavioral developmental data, we show that only the combination of the developing vocal tract, vocal apparatus muscles and nervous system can fully account for the patterns of vocal development. Together, these elements influence the shape of the monkeys’ vocal developmental landscape, tilting, rotating or shifting it in different ways. We can thus use this framework to make quantitative predictions regarding how interfering factors or experimental perturbations can change the landscape within a species, or to explain comparative differences in vocal development across species DOI: http://dx.doi.org/10.7554/eLife.20782.001 PMID:28092262

  20. Effects of fire on woody vegetation structure in African savanna.

    PubMed

    Smit, Izak P J; Asner, Gregory P; Govender, Navashni; Kennedy-Bowdoin, Ty; Knapp, David E; Jacobson, James

    2010-10-01

    Despite the importance of fire in shaping savannas, it remains poorly understood how the frequency, seasonality, and intensity of fire interact to influence woody vegetation structure, which is a key determinant of savanna biodiversity. We provide a comprehensive analysis of vertical and horizontal woody vegetation structure across one of the oldest savanna fire experiments, using new airborne Light Detection and Ranging (LiDAR) technology. We developed and compared high-resolution woody vegetation height surfaces for a series of large experimental burn plots in the Kruger National Park, South Africa. These 7-ha plots (total area approximately 1500 ha) have been subjected to fire in different seasons and at different frequencies, as well as no-burn areas, for 54 years. Long-term exposure to fire caused a reduction in woody vegetation up to the 5.0-7.5 m height class, although most reduction was observed up to 4 m. Average fire intensity was positively correlated with changes in woody vegetation structure. More frequent fires reduced woody vegetation cover more than less frequent fires, and dry-season fires reduced woody vegetation more than wet-season fires. Spring fires from the late dry season reduced woody vegetation cover the most, and summer fires from the wet season reduced it the least. Fire had a large effect on structure in the densely wooded granitic landscapes as compared to the more open basaltic landscapes, although proportionally, the woody vegetation was more reduced in the drier than in the wetter landscapes. We show that fire frequency and fire season influence patterns of vegetation three-dimensional structure, which may have cascading consequences for biodiversity. Managers of savannas can therefore use fire frequency and season in concert to achieve specific vegetation structural objectives.

  1. Woody overstorey effects on soil carbon and nitrogen pools in South African savanna

    Treesearch

    A. T. Hudak; C. A. Wessman; T. R. Seastedt

    2003-01-01

    Woody plant encroachment in savannas may alter carbon (C) and nitrogen (N) pools over the longterm, which could have regional or global biogeochemical implications given the widespread encroachment observed in the vast savanna biome. Soil and litter %C and %N were surveyed across four soil types in two encroached, semiarid savanna landscapes in northern South Africa....

  2. Urban landscape architecture design under the view of sustainable development

    NASA Astrophysics Data System (ADS)

    Chen, WeiLin

    2017-08-01

    The concept of sustainable development in modern city landscape design advocates landscape architecture, which is the main development direction in the field of landscape design. They are also effective measures to promote the sustainable development of city garden. Based on this, combined with the connotation of sustainable development and sustainable design, this paper analyzes and discusses the design of urban landscape under the concept of sustainable development.

  3. Fire history and age structure analysis in the Sherburne National Wildlife Refuge: Establishing reference conditions in a remnant oak savanna woodland

    Treesearch

    Kurt F. Kipfmueller; Tim Hepola

    2007-01-01

    Oak savanna woodlands were once a dominant ecotone throughout the upper Midwest. These ecosystems represented a transitional zone between prairie communities to the west that eventually graded into Big Woods forest. Most of the oak savanna landscapes of most of the Midwest were extensively homesteaded and farmed during the middle 1800s and few intact savanna landscapes...

  4. DNA Methylation Landscapes of Human Fetal Development.

    PubMed

    Slieker, Roderick C; Roost, Matthias S; van Iperen, Liesbeth; Suchiman, H Eka D; Tobi, Elmar W; Carlotti, Françoise; de Koning, Eelco J P; Slagboom, P Eline; Heijmans, Bastiaan T; Chuva de Sousa Lopes, Susana M

    2015-10-01

    Remodelling the methylome is a hallmark of mammalian development and cell differentiation. However, current knowledge of DNA methylation dynamics in human tissue specification and organ development largely stems from the extrapolation of studies in vitro and animal models. Here, we report on the DNA methylation landscape using the 450k array of four human tissues (amnion, muscle, adrenal and pancreas) during the first and second trimester of gestation (9,18 and 22 weeks). We show that a tissue-specific signature, constituted by tissue-specific hypomethylated CpG sites, was already present at 9 weeks of gestation (W9). Furthermore, we report large-scale remodelling of DNA methylation from W9 to W22. Gain of DNA methylation preferentially occurred near genes involved in general developmental processes, whereas loss of DNA methylation mapped to genes with tissue-specific functions. Dynamic DNA methylation was associated with enhancers, but not promoters. Comparison of our data with external fetal adrenal, brain and liver revealed striking similarities in the trajectory of DNA methylation during fetal development. The analysis of gene expression data indicated that dynamic DNA methylation was associated with the progressive repression of developmental programs and the activation of genes involved in tissue-specific processes. The DNA methylation landscape of human fetal development provides insight into regulatory elements that guide tissue specification and lead to organ functionality.

  5. Carbon Accumulation and Nitrogen Pool Recovery during Transitions from Savanna to Forest in Central Brazil

    NASA Astrophysics Data System (ADS)

    Pellegrini, A.; Hoffmann, W. A.; Franco, A. C.

    2014-12-01

    landscapes. In turn, the link between forest development and nitrogen pool recovery creates a framework for evaluating potential positive feedbacks on savanna-forest boundaries.

  6. Carbon accumulation and nitrogen pool recovery during transitions from savanna to forest in central Brazil.

    PubMed

    Pellegrini, Adam F A; Hoffmann, William A; Franco, Augusto C

    2014-02-01

    landscapes. In turn, the link between forest development and nitrogen pool recovery creates a framework for evaluating potential positive feedbacks on savanna-forest boundaries.

  7. Influence of Fire Mosaics, Habitat Characteristics and Cattle Disturbance on Mammals in Fire-Prone Savanna Landscapes of the Northern Kimberley

    PubMed Central

    Radford, Ian J.; Gibson, Lesley A.; Corey, Ben; Carnes, Karin; Fairman, Richard

    2015-01-01

    Patch mosaic burning, in which fire is used to produce a mosaic of habitat patches representative of a range of fire histories (‘pyrodiversity’), has been widely advocated to promote greater biodiversity. However, the details of desired fire mosaics for prescribed burning programs are often unspecified. Threatened small to medium-sized mammals (35 g to 5.5 kg) in the fire-prone tropical savannas of Australia appear to be particularly fire-sensitive. Consequently, a clear understanding of which properties of fire mosaics are most instrumental in influencing savanna mammal populations is critical. Here we use mammal capture data, remotely sensed fire information (i.e. time since last fire, fire frequency, frequency of late dry season fires, diversity of post-fire ages in 3 km radius, and spatial extent of recently burnt, intermediate and long unburnt habitat) and structural habitat attributes (including an index of cattle disturbance) to examine which characteristics of fire mosaics most influence mammals in the north-west Kimberley. We used general linear models to examine the relationship between fire mosaic and habitat attributes on total mammal abundance and richness, and the abundance of the most commonly detected species. Strong negative associations of mammal abundance and richness with frequency of late dry season fires, the spatial extent of recently burnt habitat (post-fire age <1 year within 3 km radius) and level of cattle disturbance were observed. Shrub cover was positively related to both mammal abundance and richness, and availability of rock crevices, ground vegetation cover and spatial extent of ≥4 years unburnt habitat were all positively associated with at least some of the mammal species modelled. We found little support for diversity of post-fire age classes in the models. Our results indicate that both a high frequency of intense late dry season fires and extensive, recently burnt vegetation are likely to be detrimental to mammals in the

  8. Influence of Fire Mosaics, Habitat Characteristics and Cattle Disturbance on Mammals in Fire-Prone Savanna Landscapes of the Northern Kimberley.

    PubMed

    Radford, Ian J; Gibson, Lesley A; Corey, Ben; Carnes, Karin; Fairman, Richard

    2015-01-01

    Patch mosaic burning, in which fire is used to produce a mosaic of habitat patches representative of a range of fire histories ('pyrodiversity'), has been widely advocated to promote greater biodiversity. However, the details of desired fire mosaics for prescribed burning programs are often unspecified. Threatened small to medium-sized mammals (35 g to 5.5 kg) in the fire-prone tropical savannas of Australia appear to be particularly fire-sensitive. Consequently, a clear understanding of which properties of fire mosaics are most instrumental in influencing savanna mammal populations is critical. Here we use mammal capture data, remotely sensed fire information (i.e. time since last fire, fire frequency, frequency of late dry season fires, diversity of post-fire ages in 3 km radius, and spatial extent of recently burnt, intermediate and long unburnt habitat) and structural habitat attributes (including an index of cattle disturbance) to examine which characteristics of fire mosaics most influence mammals in the north-west Kimberley. We used general linear models to examine the relationship between fire mosaic and habitat attributes on total mammal abundance and richness, and the abundance of the most commonly detected species. Strong negative associations of mammal abundance and richness with frequency of late dry season fires, the spatial extent of recently burnt habitat (post-fire age <1 year within 3 km radius) and level of cattle disturbance were observed. Shrub cover was positively related to both mammal abundance and richness, and availability of rock crevices, ground vegetation cover and spatial extent of ≥4 years unburnt habitat were all positively associated with at least some of the mammal species modelled. We found little support for diversity of post-fire age classes in the models. Our results indicate that both a high frequency of intense late dry season fires and extensive, recently burnt vegetation are likely to be detrimental to mammals in the

  9. The climatic sensitivity of the forest, savanna and forest-savanna transition in tropical South America.

    PubMed

    Hirota, Marina; Nobre, Carlos; Oyama, Marcos Daisuke; Bustamante, Mercedes M C

    2010-08-01

    *We used a climate-vegetation-natural fire (CVNF) conceptual model to evaluate the sensitivity and vulnerability of forest, savanna, and the forest-savanna transition to environmental changes in tropical South America. *Initially, under current environmental conditions, CVNF model results suggested that, in the absence of fires, tropical forests would extend c. 200 km into the presently observed savanna domain. *Environmental changes were then imposed upon the model in temperature, precipitation and lightning strikes. These changes ranged from 2 to 6 degrees C warming, +10 to -20% precipitation change and 0 to 15% increase in lightning frequency, which, in aggregate form, represent expected future climatic changes in response to global warming and deforestation. *The most critical vegetation changes are projected to take place over the easternmost portions of the basin, with a widening of the forest-savanna transition. The transition width would increase from 150 to c. 300 km, with tree cover losses ranging from 20 to 85%. This means that c. 6% of the areas currently covered by forests could potentially turn into grass-dominated savanna landscapes. The mechanism driving tree cover reduction consists of the combination of less favorable climate conditions for trees and more fire activity. In addition, this sensitivity analysis predicts that the current dry shrubland vegetation of northeast Brazil could potentially turn into a bare soil landscape.

  10. Drainage Network Development on a Porous Landscape

    NASA Astrophysics Data System (ADS)

    Jefferson, A.; Grant, G. E.

    2005-12-01

    Most landscape evolution models force drainage development using stream power laws, but this concept cannot be applied where a permeable substrate precludes surface runoff. Such a situation is common in volcanic landscapes throughout the world. Key processes and timescales that reduce the permeability of lava to the point where the stream power law can be applied are poorly documented. On Quaternary basaltic lava flows of the Oregon Cascades, surface drainage network development involves several stages. Measurements of soil depth show that lava <3000 years old is mostly bare rock, with no surface drainage. By ~15,000 years, soils are 5 to >30 cm deep and surface runoff may occur for short periods during peak snowmelt. We propose that, in this initial stage, permeability is reduced by void infilling from eolian or organic material as the soil mantle accumulates. GIS analysis and rock dating show that a second stage persists for several hundred thousand years, during which time drainage is primarily via groundwater, expressed in large springs at flow toes and valley walls. Incision during this stage is primarily the result of glaciation. Up slope of the springs, a low-density, ephemeral drainage network forms, often on glacial deposits. During this period, we hypothesize that lava permeability reduction occurs by weathering, secondary mineralization in voids, and compaction from overburden. In the third stage, permeability becomes low enough that surface runoff begins to dominate over groundwater. This handoff occurs between 680,000 and 2 million years, based on rock dates and drainage density. Beyond this point, further incision and drainage network expansion are stream power driven.

  11. Genomic Landscape of Developing Male Germ Cells

    PubMed Central

    Lee, Tin-Lap; Pang, Alan Lap-Yin; Rennert, Owen M.; Chan, Wai-Yee

    2010-01-01

    Spermatogenesis is a highly orchestrated developmental process by which spermatogonia develop into mature spermatozoa. This process involves many testis- or male germ cell-specific gene products whose expressions are strictly regulated. In the past decade the advent of high-throughput gene expression analytical techniques has made functional genomic studies of this process, particularly in model animals such as mice and rats, feasible and practical. These studies have just begun to reveal the complexity of the genomic landscape of the developing male germ cells. Over 50% of the mouse and rat genome are expressed during testicular development. Among transcripts present in germ cells, 40% – 60% are uncharacterized. A number of genes, and consequently their associated biological pathways, are differentially expressed at different stages of spermatogenesis. Developing male germ cells present a rich repertoire of genetic processes. Tissue-specific as well as spermatogenesis stage-specific alternative splicing of genes exemplifies the complexity of genome expression. In addition to this layer of control, discoveries of abundant presence of antisense transcripts, expressed psuedogenes, non-coding RNAs (ncRNA) including long ncRNAs, microRNAs (miRNAs) and Piwi-interacting RNAs (piRNAs), and retrogenes all point to the presence of multiple layers of expression and functional regulation in male germ cells. It is anticipated that application of systems biology approaches will further our understanding of the regulatory mechanism of spermatogenesis.† PMID:19306351

  12. Fire drives functional thresholds on the savanna-forest transition.

    PubMed

    Dantas, Vinícius de L; Batalha, Marco A; Pausas, Juli G

    2013-11-01

    In tropical landscapes, vegetation patches with contrasting tree densities are distributed as mosaics. However, the locations of patches and densities of trees within them cannot be predicted by climate models alone. It has been proposed that plant-fire feedbacks drive functional thresholds at a landscape scale, thereby maintaining open (savanna) and closed (forest) communities as two distinct stable states. However, there is little rigorous field evidence for this threshold model. Here we aim to provide support for such a model from a field perspective and to analyze the functional and phylogenetic consequences of fire in a Brazilian savanna landscape (Cerrado). We hypothesize that, in tropical landscapes, savanna and forest are two stable states maintained by plant-fire feedbacks. If so, their functional and diversity attributes should change abruptly along a community closure gradient. We set 98 plots along a gradient from open savanna to closed forest in the Brazilian Cerrado and tested for a threshold pattern in nine functional traits, five soil features, and seven diversity indicators. We then tested whether the threshold pattern was associated with different fire regimes. Most community attributes presented a threshold pattern on the savanna-forest transition with coinciding breakpoints. The thresholds separated two community states: (1) open environments with low-diversity communities growing in poor soils and dominated by plants that are highly resistant to high-intensity fires; and (2) closed environments with highly diverse plant communities growing in more fertile soils and dominated by shade-tolerant species that efficiently prevent light from reaching the understory. In addition, each state was associated with contrasting fire regimes. Our results are consistent with the hypothesis that forests and savannas are two coexisting stable states with contrasting patterns of function and diversity that are regulated by fire-plant feedbacks; our results also

  13. Landscape development modeling based on statistical framework

    NASA Astrophysics Data System (ADS)

    Pohjola, Jari; Turunen, Jari; Lipping, Tarmo; Ikonen, Ari T. K.

    2014-01-01

    Future biosphere modeling has an essential role in assessing the safety of a proposed nuclear fuel repository. In Finland the basic inputs needed for future biosphere modeling are the digital elevation model and the land uplift model because the surface of the ground is still rising due to the download stress caused by the last ice age. The future site-scale land uplift is extrapolated by fitting mathematical expressions to known data from past shoreline positions. In this paper, the parameters of this fitting have been refined based on information about lake and mire basin isolation and archaeological findings. Also, an alternative eustatic model is used in parameter refinement. Both datasets involve uncertainties so Monte Carlo simulation is used to acquire several realizations of the model parameters. The two statistical models, the digital elevation model and the refined land uplift model, were used as inputs to a GIS-based toolbox where the characteristics of lake projections for the future Olkiluoto nuclear fuel repository site were estimated. The focus of the study was on surface water bodies since they are the major transport channels for radionuclides in containment failure scenarios. The results of the study show that the different land uplift modeling schemes relying on alternative eustatic models, Moho map versions and function fitting techniques yield largely similar landscape development tracks. However, the results also point out some more improbable realizations, which deviate significantly from the main development tracks.

  14. The biosimilar insulin landscape: current developments.

    PubMed

    Lavalle-González, Fernando J; Khatami, Hootan

    2014-10-01

    Biosimilar insulins have the potential to increase access to treatment among patients with diabetes mellitus, reduce treatment costs, and expand market competition. The patents for several insulins are soon to expire, meaning there is room for copies of these products--or 'biosimilars'--to join the marketplace. It is vital that similar safety and efficacy to the innovator product is demonstrated for biosimilars. This presents many possible manufacturing and regulatory challenges. Complex manufacturing processes mean that even small differences between manufacturers can have a potential impact on the final product. Several companies are currently developing biosimilar insulins or are already producing these products in emerging markets with different regulatory requirements. For insulin biosimilars to be licensed in more established markets, manufacturers will need to meet the rigid criteria set out by agencies such as the European Medicines Agency and US Food and Drug Administration, and fulfill several pre-clinical, clinical, and pharmacovigilance surveillance criteria. As a result of differing regulatory requirements, there are possible gaps in the publically available clinical data to support the safety and efficacy of biosimilar insulins from around the world current as of July 2014. This review summarizes the current biosimilar insulin landscape.

  15. Oak savanna restoration: Oak response to fire and thinning through 28 years

    Treesearch

    Ronald E. Masters; Jack R. Waymire

    2012-01-01

    We used a small plot study on Pushmataha Wildlife Management Area in southeast Oklahoma to determine the efficacy of fire frequency and thinning as management tools for restoration of oak savanna, oak woodlands, pine-bluestem woodlands, and pine savanna for application on a landscape scale. On selected experimental units, we initially reduced stand density to favor...

  16. Textural analysis of historical aerial photography to characterize woody plant encroachment in South African savanna

    Treesearch

    Andrew T. Hudak; Carol A. Wessman

    1998-01-01

    Transitions from grassland to shrubland through woody plant encroachment result in potentially significant shifts in savanna ecosystem function. Given high resolution imagery, a textural index could prove useful for mapping woody plant densities and monitoring woody plant encroachment across savanna landscapes. Spatial heterogeneity introduced through mixtures of...

  17. EFFECTS OF PRESCRIBED FIRES ON NITROGEN FLUXES IN SAVANNA FORMATIONS OF CENTRAL BRAZIL

    EPA Science Inventory

    Savanna ecosystems are controlled by the interactions between water and nutrient availability. The savannas of Central Brazil (Cerrado) are the second most extensive plant formation in tropical South America with two million km2 of area. The Cerrado landscape contains different ...

  18. EFFECTS OF PRESCRIBED FIRES ON NITROGEN FLUXES IN SAVANNA FORMATIONS OF CENTRAL BRAZIL

    EPA Science Inventory

    Savanna ecosystems are controlled by the interactions between water and nutrient availability. The savannas of Central Brazil (Cerrado) are the second most extensive plant formation in tropical South America with two million km2 of area. The Cerrado landscape contains different ...

  19. Developing approaches for linear mixed modeling in landscape genetics through landscape-directed dispersal simulations

    USGS Publications Warehouse

    Row, Jeffrey R.; Knick, Steven T.; Oyler-McCance, Sara J.; Lougheed, Stephen C.; Fedy, Bradley C.

    2017-01-01

    Dispersal can impact population dynamics and geographic variation, and thus, genetic approaches that can establish which landscape factors influence population connectivity have ecological and evolutionary importance. Mixed models that account for the error structure of pairwise datasets are increasingly used to compare models relating genetic differentiation to pairwise measures of landscape resistance. A model selection framework based on information criteria metrics or explained variance may help disentangle the ecological and landscape factors influencing genetic structure, yet there are currently no consensus for the best protocols. Here, we develop landscape-directed simulations and test a series of replicates that emulate independent empirical datasets of two species with different life history characteristics (greater sage-grouse; eastern foxsnake). We determined that in our simulated scenarios, AIC and BIC were the best model selection indices and that marginal R2 values were biased toward more complex models. The model coefficients for landscape variables generally reflected the underlying dispersal model with confidence intervals that did not overlap with zero across the entire model set. When we controlled for geographic distance, variables not in the underlying dispersal models (i.e., nontrue) typically overlapped zero. Our study helps establish methods for using linear mixed models to identify the features underlying patterns of dispersal across a variety of landscapes.

  20. Developing approaches for linear mixed modeling in landscape genetics through landscape-directed dispersal simulations.

    PubMed

    Row, Jeffrey R; Knick, Steven T; Oyler-McCance, Sara J; Lougheed, Stephen C; Fedy, Bradley C

    2017-06-01

    Dispersal can impact population dynamics and geographic variation, and thus, genetic approaches that can establish which landscape factors influence population connectivity have ecological and evolutionary importance. Mixed models that account for the error structure of pairwise datasets are increasingly used to compare models relating genetic differentiation to pairwise measures of landscape resistance. A model selection framework based on information criteria metrics or explained variance may help disentangle the ecological and landscape factors influencing genetic structure, yet there are currently no consensus for the best protocols. Here, we develop landscape-directed simulations and test a series of replicates that emulate independent empirical datasets of two species with different life history characteristics (greater sage-grouse; eastern foxsnake). We determined that in our simulated scenarios, AIC and BIC were the best model selection indices and that marginal R(2) values were biased toward more complex models. The model coefficients for landscape variables generally reflected the underlying dispersal model with confidence intervals that did not overlap with zero across the entire model set. When we controlled for geographic distance, variables not in the underlying dispersal models (i.e., nontrue) typically overlapped zero. Our study helps establish methods for using linear mixed models to identify the features underlying patterns of dispersal across a variety of landscapes.

  1. Landscape development, forest fires, and wilderness management.

    PubMed

    Wright, H E

    1974-11-08

    Both the landforms and the vegetation of the earth develop to states that are maintained in dynamic equilibrium. Short-term equilibrium of a hillslope or river valley results from intersection between erosional and depositional tendencies, controlled by gravitational force and the efficiency of the transporting medium. Long-term equilibrium of major landforms depends on crustal uplift and the resistance of the rock to weathering. In most parts of the world landscape evolves toward a peneplain, but the reduction rate approaches zero as the cycle progresses, and the counteracting force of crustal uplift intercedes before the end form is reached. Davis described this theoretical model in elegant terms. Leopold and Hack have provided a new and quantitative understanding of short-range geomorphic interactions that tend to discredit the Davisian model in the eyes of many. However, the substitute models of quasi-equilibrium or dynamic equilibrium merely describe short-range situations in which this or that Davisian stage is maintained despite uplift or downwasting. Given crustal stability and an unchanging climate, landforms would presumably still evolve through Davisian stages. However, the Davis model cannot be tested, for despite tremendous inventions in geochronology and impressive advances in stratigraphic knowledge, we cannot yet establish the rates or even the fact of crustal uplift in most areas. We are left with an unresolvable problem, for the sedimentary records of erosional history are largely inaccessible, undatable, and indecipherable, at least in the detail necessary to describe long-term evolution of the landscape. We know more about the evolution and maintenance of vegetation assemblages than about landform evolution, for even long-term vegetation sequences are within the scope of radiocarbon dating, and the biostratigraphic record is detailed. Even here, however, distinctions between short-term and long-term situations must be made, so that Clements

  2. Lidar remote sensing of savanna biophysical attributes

    NASA Astrophysics Data System (ADS)

    Gwenzi, David

    plot level biomass into wall-to-wall maps that provide more ecological information. We evaluated the utility of three spatial modeling approaches to address this problem: deterministic methods, geostatistical methods and an image segmentation approach. Overall, the mean pixel biomass estimated by the 3 approaches did not differ significantly but the output maps showed marked differences in the estimation precision and ability of each model to mimic the primary variable's trend across the landscape. The results emphasized the need for future satellite lidar missions to consider increasing the sampling intensity across track so that biomass observations are made and characterized at the scale at which they vary. We used data from the Multiple Altimeter Beam Experimental Lidar (MABEL), an airborne photon counting lidar sensor developed by NASA Goddard to simulate ICESat-2 data. We segmented each transect into different block sizes and calculated canopy top and mean ground elevation based on the structure of the histogram of the block's aggregated photons. Our algorithm was able to compute canopy height and generate visually meaningful vegetation profiles at MABEL's signal and noise levels but a simulation of the expected performance of ICESat-2 by adjusting MABEL data's detected number of signal and noise photons to that predicted using ATLAS instrument model design cases indicated that signal photons will be substantially lower. The lower data resolution reduces canopy height estimation precision especially in areas of low density vegetation cover. Given the clear difficulties in processing simulated ATLAS data, it appears unlikely that it will provide the kind of data required for mapping of the biophysical properties of savanna vegetation. Rather, resources are better concentrated on preparing for the Global Ecosystem Dynamics Investigation (GEDI) mission, a waveform lidar mission scheduled to launch by the end of this decade. In addition to the full waveform technique

  3. Installation restoration general environmental technology development. Task 2. Incineration test of explosives contaminated soils at Savanna Army Depot activity, Savanna, Illinois. Final report Sep 82-Jan 84

    SciTech Connect

    Noland, J.W.; Marks, J.R.; Marks, P.J.

    1984-04-01

    This report presents the results of a comprehensive study which successfully demonstrates the effectiveness of incineration as a decontamination method for explosives contaminated soils. The project included: incineration equipment and test site selection, soil characterization and reactivity testing, development of a detailed test plan and site plan safety submission, environmental permitting, evaluation of materials handling procedures, incineration testing, and evaluation of results.

  4. Aridity, not fire, favors nitrogen-fixing plants across tropical savanna and forest biomes.

    PubMed

    Pellegrini, Adam F A; Staver, A Carla; Hedin, Lars O; Charles-Dominique, Tristan; Tourgee, Amy

    2016-09-01

    Tropical savannas are hypothesized to be hot spots of nitrogen-fixer diversity and activity because of the high disturbance and low nitrogen characteristic of savanna landscapes. Here we compare the abundances of nitrogen-fixing and non-fixing trees in both tropical savannas and tropical forests under climatically equivalent conditions, using plant inventory studies across 566 plots in South America and Africa. A single factor, aridity, explained 19-54% of the variance in fixer abundance, and unexpectedly was more important than fire frequency, biome, and continent. Nitrogen fixers were more abundant in arid environments; as a result, African savannas, which tend to be drier, were richer in nitrogen fixers than South American savannas. Fixer abundance converged on similar levels in forests in both continents. We conclude that climate plays a greater role than fire in determining the distribution of nitrogen fixers across tropical savanna and forest biomes.

  5. Trade-offs between savanna woody plant diversity and carbon storage in the Brazilian Cerrado.

    PubMed

    Pellegrini, Adam F A; Socolar, Jacob B; Elsen, Paul R; Giam, Xingli

    2016-10-01

    Incentivizing carbon storage can be a win-win pathway to conserving biodiversity and mitigating climate change. In savannas, however, the situation is more complex. Promoting carbon storage through woody encroachment may reduce plant diversity of savanna endemics, even as the diversity of encroaching forest species increases. This trade-off has important implications for the management of biodiversity and carbon in savanna habitats, but has rarely been evaluated empirically. We quantified the nature of carbon-diversity relationships in the Brazilian Cerrado by analyzing how woody plant species richness changed with carbon storage in 206 sites across the 2.2 million km(2) region at two spatial scales. We show that total woody plant species diversity increases with carbon storage, as expected, but that the richness of endemic savanna woody plant species declines with carbon storage both at the local scale, as woody biomass accumulates within plots, and at the landscape scale, as forest replaces savanna. The sharpest trade-offs between carbon storage and savanna diversity occurred at the early stages of carbon accumulation at the local scale but the final stages of forest encroachment at the landscape scale. Furthermore, the loss of savanna species quickens in the final stages of forest encroachment, and beyond a point, savanna species losses outpace forest species gains with increasing carbon accumulation. Our results suggest that although woody encroachment in savanna ecosystems may provide substantial carbon benefits, it comes at the rapidly accruing cost of woody plant species adapted to the open savanna environment. Moreover, the dependence of carbon-diversity trade-offs on the amount of savanna area remaining requires land managers to carefully consider local conditions. Widespread woody encroachment in both Australian and African savannas and grasslands may present similar threats to biodiversity. © 2016 John Wiley & Sons Ltd.

  6. Towards developing Kentucky's landscape change maps

    USGS Publications Warehouse

    Zourarakis, D.P.; Lambert, S.C.; Palmer, M.

    2003-01-01

    The Kentucky Landscape Snapshot Project, a NASA-funded project, was established to provide a first baseline land cover/land use map for Kentucky. Through this endeavor, change detection will be institutionalized, thus aiding in decision-making at the local, state, and federal planning levels. 2002 Landsat 7 imaginery was classified following and Anderson Level III scheme, providing an enhancement over the 1992 USGS National Land Cover Data Set. Also as part of the deliverables, imperviousness and canopy closure layers were produced with the aid of IKONOS high resolution, multispectral imagery.

  7. Nutrient limitation in tropical savannas across multiple scales and mechanisms.

    PubMed

    Pellegrini, Adam F A

    2016-02-01

    Nutrients have been hypothesized to influence the distribution of the savanna biome through two possible mechanisms. Low nutrient availability may restrict growth rates of trees, thereby allowing for intermittent fires to maintain low tree cover; alternatively, nutrient deficiency may even place an absolute constraint on the ability of forests to form, independent of fire. However, we have little understanding of the scales at which nutrient limitation operates, what nutrients are limiting, and the mechanisms that influence how nutrient limitation regulates savanna-forest transitions. Here, I review literature, synthesize existing data, and present a simple calculation of nutrient demand to evaluate how nutrient limitation may regulate the distribution of the savanna biome. The literature primarily supports the hypothesis that nutrients may interact dynamically with fire to restrict the transition of savanna into forest. A compilation of indirect metrics of nutrient limitation suggest that nitrogen and phosphorus are both in short supply and may limit plants. Nutrient demand calculations provided a number of insights. First, trees required high rates of nitrogen and phosphorus supply relative to empirically determined inputs. Second, nutrient demand increased as landscapes approached the transition point between savanna and forest. Third, the potential for fire-driven nutrient losses remained high throughout transitions, which may exaggerate limitation and could be a key feedback stabilizing the savanna biome. Fourth, nutrient limitation varied between functional groups, with fast-growing forest species having substantially greater nutrient demand and a higher susceptibility to fire-driven nutrient losses. Finally, African savanna trees required substantially larger amounts of nutrients supplied at greater rates, although this varied across plant functional groups. In summary, the ability of nutrients to control transitions emerges at individual and landscape

  8. The application of local measures of spatial autocorrelation for describing pattern in north Australian landscapes.

    PubMed

    Pearson, Diane M

    2002-01-01

    This paper tests the use of a spatial analysis technique, based on the calculation of local spatial autocorrelation, as a possible approach for modelling and quantifying structure in northern Australian savanna landscapes. Unlike many landscapes in the world, northern Australian savanna landscapes appear on the surface to be intact. They have not experienced the same large-scale land clearance and intensive land management as other landscapes across Australia. Despite this, natural resource managers are beginning to notice that processes are breaking down and declines in species are becoming more evident. With future declines of species looking more imminent it is particularly important that models are available that can help to assess landscape health, and quantify any structural change that takes place. GIS and landscape ecology provide a useful way of describing landscapes both spatially and temporally and have proved to be particularly useful for understanding vegetation structure or pattern in landscapes across the world. There are many measures that examine spatial structure in the landscape and most of these are now available in a GIS environment (e.g. FRAGSTATS* ARC, r.le, and Patch Analyst). All these methods depend on a landscape described in terms of patches, corridors and matrix. However, since landscapes in northern Australia appear to be relatively intact they tend to exist as surfaces of continuous variation rather than in clearly defined homogeneous units. As a result they cannot be easily described using entity-based models requiring patches and other essentially cartographic approaches. This means that more appropriate methods need to be developed and explored. The approach examined in this paper enables clustering and local pattern in the data to be identified and forms a generic method for conceptualising the landscape structure where patches are not obvious and where boundaries between landscape features are difficult to determine. Two sites

  9. Silviculture to restore oak savannas and woodlands

    Treesearch

    Daniel C. Dey; John M. Kabrick; Callie J. Schweitzer

    2017-01-01

    Variability in historic fire regimes in eastern North America resulted in an array of oak natural communities that were dominant across the region. In the past century, savannas and woodlands have become scarce because of conversion to agriculture or development of forest structure in the absence of fire. Their restoration is a primary goal for public agencies and...

  10. Climatic Limits on Landscape Development in the Northwestern Himalaya

    PubMed

    Brozović; Burbank; Meigs

    1997-04-25

    The interaction between tectonism and erosion produces rugged landscapes in actively deforming regions. In the northwestern Himalaya, the form of the landscape was found to be largely independent of exhumation rates, but regional trends in mean and modal elevations, hypsometry (frequency distribution of altitude), and slope distributions were correlated with the extent of glaciation. These observations imply that in mountain belts that intersect the snowline, glacial and periglacial processes place an upper limit on altitude, relief, and the development of topography irrespective of the rate of tectonic processes operating.

  11. a Cultural Landscape Information System Developed with Open Source Tools

    NASA Astrophysics Data System (ADS)

    Chudyk, C.; Müller, H.; Uhler, M.; Würriehausen, F.

    2013-07-01

    Since 2010, the state of Rhineland-Palatinate in Germany has developed a cultural landscape information system as a process to secure and further enrich aggregate data about its cultural assets. In an open dialogue between governing authorities and citizens, the intention of the project is an active cooperation of public and private actors. A cultural landscape information system called KuLIS was designed as a web platform, combining semantic wiki software with a geographic information system. Based on data sets from public administrations, the information about cultural assets can be extended and enhanced by interested participants. The developed infrastructure facilitates local information accumulation through a crowdsourcing approach. This capability offers new possibilities for e-governance and open data developments. The collaborative approach allows governing authorities to manage and supervise official data, while public participation enables affordable information acquisition. Gathered cultural heritage information can provide incentives for touristic valorisation of communities or concepts for strengthening regional identification. It can also influence political decisions in defining significant cultural regions worth of protecting from industrial influences. The presented cultural landscape information allows citizens to influence the statewide development of cultural landscapes in a democratic way.

  12. Career Development in Canada: A Changing Landscape.

    ERIC Educational Resources Information Center

    Kellett, Ralph

    In Canada, responsibility for the career development delivery system is divided among federal, provincial/territorial, and municipal levels of government. Education comes under provincial/territorial jurisdiction. Career development varies across provinces and often from school to school. There are eight transition points throughout the school…

  13. Career Development in Canada: A Changing Landscape.

    ERIC Educational Resources Information Center

    Kellett, Ralph

    In Canada, responsibility for the career development delivery system is divided among federal, provincial/territorial, and municipal levels of government. Education comes under provincial/territorial jurisdiction. Career development varies across provinces and often from school to school. There are eight transition points throughout the school…

  14. Determinants of woody encroachment and cover in African savannas.

    PubMed

    Devine, Aisling P; McDonald, Robbie A; Quaife, Tristan; Maclean, Ilya M D

    2017-04-01

    Savanna ecosystems are an integral part of the African landscape and sustain the livelihoods of millions of people. Woody encroachment in savannas is a widespread phenomenon but its causes are widely debated. We review the extensive literature on woody encroachment to help improve understanding of the possible causes and to highlight where and how future scientific efforts to fully understand these causes should be focused. Rainfall is the most important determinant of maximum woody cover across Africa, but fire and herbivory interact to reduce woody cover below the maximum at many locations. We postulate that woody encroachment is most likely driven by CO2 enrichment and propose a two-system conceptual framework, whereby mechanisms of woody encroachment differ depending on whether the savanna is a wet or dry system. In dry savannas, the increased water-use efficiency in plants relaxes precipitation-driven constraints and increases woody growth. In wet savannas, the increase of carbon allocation to tree roots results in faster recovery rates after disturbance and a greater likelihood of reaching sexual maturity. Our proposed framework can be tested using a mixture of experimental and earth observational techniques. At a local level, changes in precipitation, burning regimes or herbivory could be driving woody encroachment, but are unlikely to be the explanation of this continent-wide phenomenon.

  15. Tree and stand transpiration in a Midwestern bur oak savanna after elm encroachment and restoration thinning

    USGS Publications Warehouse

    Asbjornsen, H.; Tomer, M.D.; Gomez-Cardenas, M.; Brudvig, L.A.; Greenan, C.M.; Schilling, K.

    2007-01-01

    Oak savannas, once common in the Midwest, are now isolated remnants within agricultural landscapes. Savanna remnants are frequently encroached by invasive trees to become woodlands. Thinning and prescribed burning can restore savanna structure, but the ecohydrological effects of managing these remnants are poorly understood. In this study, we measured sap flow (Js) to quantify transpiration in an Iowa bur oak (Quercus macrocarpa) savanna woodland encroached by elms (Ulmus americana), and in an adjacent restored savanna after thinning to remove elms, during summer 2004. Savanna oaks had greater mean daily Js (35.9 L dm-2 day-1) than woodland oaks (20.7 L dm-2 day-1) and elms (12.4 L dm-2 day-1). The response of Js to vapor pressure deficit (D) was unexpectedly weak, although oaks in both stands showed negative correlation between daily Js and D for D > 0.4 kPa. An earlier daily peak in Js in the elm trees showed a possible advantage for water uptake. As anticipated, the woodland's stand transpiration was greater (1.23 mm day-1) than the savanna's (0.35 mm day-1), yet the savanna achieved 30% of the woodland's transpiration with only 11% of its sapwood area. The difference in transpiration influenced water table depths, which were 2 m in the savanna and 6.5 m in the woodland. Regionally, row-crop agriculture has increased groundwater recharge and raised water tables, providing surplus water that perhaps facilitated elm encroachment. This has implications for restoration of savanna remnants. If achieving a savanna ecohydrology is an aim of restoration, then restoration strategies may require buffers, or targeting of large or hydrologically isolated remnants. ?? 2007.

  16. The dynamic landscape of exceptional language development.

    PubMed

    Peltzer-Karpf, Annemarie

    2012-06-01

    Developmental neurocognitive studies have shown that the brain systems supporting the emergence of sensory and cognitive abilities display different profiles of neuroplasticity. The research question posed here is to what extent sensory deprivation influences the dynamics of language development. The findings reported are grounded in studies with vision-impaired children with sighted peers featured as controls (age range 18 months to 3 years). Their data are matched against findings on advanced language development in blind children (age range: from 6 to 10 years; N = 12) and hearing-impaired and deaf children (age range: from 5 to 11 years; N = 20). The data give evidence that language acquisition in sensory-impaired children follows the same overall developmental path with respect to macrostructural changes and the succession of phase-shifts. System-specific temporal discrepancies expressed in protracted phase-shifts and delayed increases of variability are most evident in the early phases. Self-organizing maps (SOMs) help to visualize individual and group-specific variation. The dynamic framework used (1) shows a higher sensibility to system-specific changes, (2) enhances the informative value of the data assessed, and (3) facilitates reliable prognoses concerning the child's cognitive and linguistic future.

  17. Beyond precipitation: physiographic gradients dictate the relative importance of environmental drivers on Savanna vegetation.

    PubMed

    Campo-Bescós, Miguel A; Muñoz-Carpena, Rafael; Kaplan, David A; Southworth, Jane; Zhu, Likai; Waylen, Peter R

    2013-01-01

    Understanding the drivers of large-scale vegetation change is critical to managing landscapes and key to predicting how projected climate and land use changes will affect regional vegetation patterns. This study aimed to improve our understanding of the role, magnitude and spatial distribution of the key environmental factors driving vegetation change in southern African savanna, and how they vary across physiographic gradients. We applied Dynamic Factor Analysis (DFA), a multivariate times series dimension reduction technique to ten years of monthly remote sensing data (MODIS-derived normalized difference vegetation index, NDVI) and a suite of environmental covariates: precipitation, mean and maximum temperature, soil moisture, relative humidity, fire and potential evapotranspiration. Monthly NDVI was described by cyclic seasonal variation with distinct spatiotemporal patterns in different physiographic regions. Results support existing work emphasizing the importance of precipitation, soil moisture and fire on NDVI, but also reveal overlooked effects of temperature and evapotranspiration, particularly in regions with higher mean annual precipitation. Critically, spatial distributions of the weights of environmental covariates point to a transition in the importance of precipitation and soil moisture (strongest in grass-dominated regions with precipitation<750 mm) to fire, potential evapotranspiration, and temperature (strongest in tree-dominated regions with precipitation>950 mm). We quantified the combined spatiotemporal effects of an available suite of environmental drivers on NDVI across a large and diverse savanna region. The analysis supports known drivers of savanna vegetation but also uncovers important roles of temperature and evapotranspiration. Results highlight the utility of applying the DFA approach to remote sensing products for regional analyses of landscape change in the context of global environmental change. With the dramatic increase in global

  18. Beyond Precipitation: Physiographic Gradients Dictate the Relative Importance of Environmental Drivers on Savanna Vegetation

    PubMed Central

    Campo-Bescós, Miguel A.; Muñoz-Carpena, Rafael; Kaplan, David A.; Southworth, Jane; Zhu, Likai; Waylen, Peter R.

    2013-01-01

    Background Understanding the drivers of large-scale vegetation change is critical to managing landscapes and key to predicting how projected climate and land use changes will affect regional vegetation patterns. This study aimed to improve our understanding of the role, magnitude and spatial distribution of the key environmental factors driving vegetation change in southern African savanna, and how they vary across physiographic gradients. Methodology/Principal Findings We applied Dynamic Factor Analysis (DFA), a multivariate times series dimension reduction technique to ten years of monthly remote sensing data (MODIS-derived normalized difference vegetation index, NDVI) and a suite of environmental covariates: precipitation, mean and maximum temperature, soil moisture, relative humidity, fire and potential evapotranspiration. Monthly NDVI was described by cyclic seasonal variation with distinct spatiotemporal patterns in different physiographic regions. Results support existing work emphasizing the importance of precipitation, soil moisture and fire on NDVI, but also reveal overlooked effects of temperature and evapotranspiration, particularly in regions with higher mean annual precipitation. Critically, spatial distributions of the weights of environmental covariates point to a transition in the importance of precipitation and soil moisture (strongest in grass-dominated regions with precipitation<750 mm) to fire, potential evapotranspiration, and temperature (strongest in tree-dominated regions with precipitation>950 mm). Conclusions/Significance We quantified the combined spatiotemporal effects of an available suite of environmental drivers on NDVI across a large and diverse savanna region. The analysis supports known drivers of savanna vegetation but also uncovers important roles of temperature and evapotranspiration. Results highlight the utility of applying the DFA approach to remote sensing products for regional analyses of landscape change in the context of

  19. Effects of restoring oak savannas on bird communities and populations.

    PubMed

    Brawn, Jeffrey D

    2006-04-01

    Efforts to restore and maintain oak savannas in North America, with emphasis on the use of prescribed fire, have become common. Little is known, however about how restoration affects animal populations, especially those of birds. I compared the breeding densities, community structure, and reproductive success of birds in oak savannas maintained by prescribed fire (12 sites) with those in closed-canopy forests (13 sites). All sampling was conducted in Illinois (U.S.A.). Of the 31 bird species analyzed, 12 were more common in savannas, 14 were not affected by habitat structure, and 5 were more common in forest habitat. The species favored by disturbance and restoration included Northern Bobwhites (Colinus virginianus), Mourning Doves (Zenaida macroura), Red-headed Woodpeckers (Melanerpes erythrocephalus), Indigo Buntings (Passerina cyanea), and Baltimore Orioles (Icterus galbula). Those more common in closed-canopy forest included Ovenbirds (Seiurus aurocapilla) and Wood Thrushes (Hylocichla mustelina). Few species were unique to one type of habitat, but overall avian community structure in oak savannas and closed-canopy forests was generally distinctive. Estimates of nesting success (derived from 785 nests) revealed that 6 of the 13 species considered experienced greater productivity in the savanna habitat. Rates of brood parasitism were unaffected by restoration and habitat structure. Within savannas, tract size had little effect on breeding abundances and reproductive success. My results illustrate that restoration techniques can significantly affect the ecology of constituent animal populations and communities and have key implications regarding avian conservation and the management of forest habitat in fragmented landscapes. Small patches of forest habitat that regularly function as population sinks may offer far better prospects for birds if they are subjected to disturbance and ecosystem restoration.

  20. From forest landscape to agricultural landscape in the developing tropical country of Malaysia: pattern, process, and their significance on policy.

    PubMed

    Abdullah, Saiful Arif; Hezri, Adnan A

    2008-11-01

    Agricultural expansion and deforestation are spatial processes of land transformation that impact on landscape pattern. In peninsular Malaysia, the conversion of forested areas into two major cash crops--rubber and oil palm plantations--has been identified as driving significant environmental change. To date, there has been insufficient literature studying the link between changes in landscape patterns and land-related development policies. Therefore, this paper examines: (i) the links between development policies and changes in land use/land cover and landscape pattern and (ii) the significance and implications of these links for future development policies. The objective is to generate insights on the changing process of land use/land cover and landscape pattern as a functional response to development policies and their consequences for environmental conditions. Over the last century, the development of cash crops has changed the country from one dominated by natural landscapes to one dominated by agricultural landscapes. But the last decade of the century saw urbanization beginning to impact significantly. This process aligned with the establishment of various development policies, from land development for agriculture between the mid 1950s and the 1970s to an emphasis on manufacturing from the 1980s onward. Based on a case study in Selangor, peninsular Malaysia, a model of landscape pattern change is presented. It contains three stages according to the relative importance of rubber (first stage: 1900--1950s), oil palm (second stage: 1960s--1970s), and urban (third stage: 1980s--1990s) development that influenced landscape fragmentation and heterogeneity. The environmental consequences of this change have been depicted through loss of biodiversity, geohazard incidences, and the spread of vector-borne diseases. The spatial ecological information can be useful to development policy formulation, allowing diagnosis of the country's "health" and sustainability. The

  1. From Forest Landscape to Agricultural Landscape in the Developing Tropical Country of Malaysia: Pattern, Process, and Their Significance on Policy

    NASA Astrophysics Data System (ADS)

    Abdullah, Saiful Arif; Hezri, Adnan A.

    2008-11-01

    Agricultural expansion and deforestation are spatial processes of land transformation that impact on landscape pattern. In peninsular Malaysia, the conversion of forested areas into two major cash crops—rubber and oil palm plantations—has been identified as driving significant environmental change. To date, there has been insufficient literature studying the link between changes in landscape patterns and land-related development policies. Therefore, this paper examines: (i) the links between development policies and changes in land use/land cover and landscape pattern and (ii) the significance and implications of these links for future development policies. The objective is to generate insights on the changing process of land use/land cover and landscape pattern as a functional response to development policies and their consequences for environmental conditions. Over the last century, the development of cash crops has changed the country from one dominated by natural landscapes to one dominated by agricultural landscapes. But the last decade of the century saw urbanization beginning to impact significantly. This process aligned with the establishment of various development policies, from land development for agriculture between the mid 1950s and the 1970s to an emphasis on manufacturing from the 1980s onward. Based on a case study in Selangor, peninsular Malaysia, a model of landscape pattern change is presented. It contains three stages according to the relative importance of rubber (first stage: 1900-1950s), oil palm (second stage: 1960s-1970s), and urban (third stage: 1980s-1990s) development that influenced landscape fragmentation and heterogeneity. The environmental consequences of this change have been depicted through loss of biodiversity, geohazard incidences, and the spread of vector-borne diseases. The spatial ecological information can be useful to development policy formulation, allowing diagnosis of the country’s “health” and sustainability

  2. Biodiversity effects on ecosystem function due to land use: The case of buffel savannas in the Sky Islands Seas in the central region of Sonora

    Treesearch

    A. E. Castellanos; H. Celaya; C. Hinojo; A. Ibarra; J. R. Romo

    2013-01-01

    Buffel savannas have been an important landscape on cattle grazing ranches in Sonora over the past 50 years or more. Changes in land use result in biodiversity changes that may produce ecosystem functional changes; however, these are less well documented. Although fire driven processes have been proposed for Buffel savannas, this is not generally the case, and other...

  3. Assessing the visual resource and visual development suitability values in metropolitanizing landscapes

    Treesearch

    Charles B. Yuill; Spencer A. Joyner Jr.

    1979-01-01

    In response to urbanization pressures on the New England landscape, researchers at the University of Massachusetts have developed and tested two visual landscape assessment procedures as part of a comprehensive research project in landscape planning. The first procedure identifies those visually significant and unique areas within a town or region that warrant public...

  4. The contribution of trees and grasses to productivity of an Australian tropical savanna

    NASA Astrophysics Data System (ADS)

    Moore, Caitlin E.; Beringer, Jason; Evans, Bradley; Hutley, Lindsay B.; McHugh, Ian; Tapper, Nigel J.

    2016-04-01

    Savanna ecosystems cover 20 % of the global land surface and account for 25 % of global terrestrial carbon uptake. They support one fifth of the world's human population and are one of the most important ecosystems on our planet. Savanna productivity is a product of the interplay between trees and grass that co-dominate savanna landscapes and are maintained through interactions with climate and disturbance (fire, land use change, herbivory). In this study, we evaluate the temporally dynamic partitioning of overstory and understory carbon dioxide fluxes in Australian tropical savanna using overstory and understory eddy covariance measurements. Over a 2-year period (September 2012 to October 2014) the overall net ecosystem productivity (NEP) of the savanna was 506.2 (±22 SE) g C m-2 yr-1. The total gross primary productivity (GPP) was 2267.1 (±80 SE) g C m-2 yr-1, of which the understory contributed 32 %. The understory contribution was strongly seasonal, with most GPP occurring in the wet season (40 % of total ecosystem in the wet season and 18 % in the dry). This study is the first to elucidate the temporal dynamics of savanna understory and overstory carbon flux components explicitly using observational information. Understanding grass productivity is crucial for evaluating fuel loads, as is tree productivity for quantifying the tree carbon sink. This information will contribute to a significant refinement of the representation of savannas in models, as well as improved understanding of relative tree-grass productivity and competition for resources.

  5. The contribution of trees and grasses to productivity of an Australian tropical savanna

    NASA Astrophysics Data System (ADS)

    Moore, C. E.; Beringer, J.; Evans, B.; Hutley, L. B.; McHugh, I.; Tapper, N. J.

    2015-12-01

    Savanna ecosystems cover 20 % of the global land surface and account for 25 % of global terrestrial carbon uptake. They support one fifth of the world's human population and are one of the most important ecosystems on our planet. Savanna productivity is a product of the interplay between trees and grass that co-dominate savanna landscapes and are maintained through interactions with climate and disturbance (fire, land use change, herbivory). In this study, we evaluate the temporally dynamic partitioning of overstory and understory carbon dioxide fluxes in Australian tropical savanna using overstory and understory eddy covariance measurements. Over a two year period (September 2012 to October 2014) the overall net ecosystem productivity (NEP) of the savanna was 506.2 (±22 SE) g C m-2 yr-1. The total gross primary productivity (GPP) was 2267.1 (±80 SE) g C m-2 yr-1, of which the understory contributed 32 %. The understory contribution was strongly seasonal, with most GPP occurring in the wet season (40 % of total ecosystem in the wet season and 18 % in the dry). This study is the first to elucidate the temporal dynamics of savanna understory and overstory carbon flux components explicitly using observational information. Understanding grass productivity is crucial for evaluating fuel loads, as is tree productivity for quantifying the tree carbon sink. This information will contribute to a significant refinement of the representation of savannas in models, as well as improved understanding of relative tree-grass productivity and competition for resources.

  6. Land use scenarios development and impacts assessment on vegetation carbon/nitrogen sequestration in the West African Sudan savanna watershed, Benin

    NASA Astrophysics Data System (ADS)

    Chabi, A.

    2015-12-01

    ackground: Reduced Emissions from Deforestation and Degradation (REDD+), being developed through the United Nations Framework Convention on Climate Change (UNFCCC) requires information on the carbon/nitrogen stocks in the plant biomass for predicting future climate under scenarios development. The development of land use scenarios in West Africa is needed to predict future impacts of change in the environment and the socio-economic status of rural communities. The study aims at developing land use scenario based on mitigation strategy to climate change as an issue of contributing for carbon and nitrogen sequestration, the condition 'food focused' as a scenario based crop production and 'financial investment' as scenario based on an economic development pathway, and to explore the possible future temporal and spatial impacts on vegetation carbon/nitrogen sequestration/emission and socio-economic status of rural communities. Preliminary results: BEN-LUDAS (Benin-Land Use DyNamic Simulator) model, carbon and nitrogen equations, remote sensing and socio-economic data were used to predict the future impacts of each scenario in the environment and human systems. The preliminary results which are under analysis will be presented soon. Conclusion: The proposed BEN-LUDAS models will help to contribute to policy decision making at the local and regional scale and to predict future impacts of change in the environment and socio-economic status of the rural communities. Keywords: Land use scenarios development, BEN-LUDAS, socio-economic status of rural communities, future impacts of change, assessment, West African Sudan savanna watershed, Benin

  7. Tectonic and Climatic Controls on Landscape Development of Puerto Rico

    NASA Astrophysics Data System (ADS)

    Rogers, R. D.; Salas, M.; Colon, A.

    2007-12-01

    The northeastern Caribbean island of Puerto Rico is an exhumed Cenozoic island arc situated between the inactive Muertos trench to the south and the highly oblique Puerto Rican Trench to the north that forms the left- lateral strike-slip plate margin with North America. The rectangular island's long axis of 175 km parallels the east trending strike of the trenches with a near constant width of between 50 and 60 km. Puerto Rico receives the NE trade winds and has a tropical monsoonal climate. Puerto Rico has a distinct midline asymmetry with north draining watershed about twice the length and five times as large as south draining watershed. This midline asymmetry is more pronounced along the islands eastern third than the central or western thirds. River outlet spacing, mountain front sinuosity, and comparative hypsometry display similar east to west variability consistent with greater denudation in the eastern parts of the island. The southwestern fifth of the island is underlain by serpentinized ocean crust that forms the large diapiric Monte del Estado uplift. Active diapirism is indicated by highly asymmetric watersheds of the surrounding rivers and tributaries. Stream length gradient index calculated from 1:20,000 scale map data and compared to fault locations show little correlation suggesting that active faults does not significantly control Puerto Rico's landscape. Quantified morphologic data from the eastern two-thirds of Puerto Rico are consistent with a landscape developed in response to the precipitation derived from NE trade winds while serpentinite diapirism dominates the western third of the island. Individual active faults of Puerto Rico do not control the landscape development.

  8. Transposon tools: worldwide landscape of intellectual property and technological developments.

    PubMed

    Palazzoli, Fabien; Testu, François-Xavier; Merly, Franck; Bigot, Yves

    2010-03-01

    DNA transposons are considered to be good candidates for developing tools for genome engineering, insertional mutagenesis and gene delivery for therapeutic purposes, as illustrated by the recent first clinical trial of a transposon. In this article we set out to highlight the interest of patent information, and to develop a strategy for the technological development of transposon tools, similar to what has been done in many other fields. We propose a patent landscape for transposon tools, including the changes in international patent applications, and review the leading inventors and applicants. We also provide an overview of the potential patent portfolio for the prokaryotic and eukaryotic transposons that are exploited by spin-off companies. Finally, we discuss the difficulties involved in tracing relevant state-of-the-art of articles and patent documents, based on the example of one of the most promising transposon systems, including all the impacts on the technological development of transposon tools.

  9. Unsustainable fuelwood extraction from South African savannas

    NASA Astrophysics Data System (ADS)

    Wessels, K. J.; Colgan, M. S.; Erasmus, B. F. N.; Asner, G. P.; Twine, W. C.; Mathieu, R.; van Aardt, J. A. N.; Fisher, J. T.; Smit, I. P. J.

    2013-03-01

    Wood and charcoal supply the majority of sub-Saharan Africa’s rural energy needs. The long-term supply of fuelwood is in jeopardy given high consumption rates. Using airborne light detection and ranging (LiDAR), we mapped and investigated savanna aboveground biomass across contrasting land uses, ranging from densely populated communal areas to highly protected areas in the Lowveld savannas of South Africa. We combined the LiDAR observations with socio-economic data, biomass production rates and fuelwood consumption rates in a supply-demand model to predict future fuelwood availability. LiDAR-based biomass maps revealed disturbance gradients around settlements up to 1.5 km, corresponding to the maximum distance walked to collect fuelwood. At current levels of fuelwood consumption (67% of households use fuelwood exclusively, with a 2% annual reduction), we calculate that biomass in the study area will be exhausted within thirteen years. We also show that it will require a 15% annual reduction in consumption for eight years to a level of 20% of households using fuelwood before the reduction in biomass appears to stabilize to sustainable levels. The severity of dwindling fuelwood reserves in African savannas underscores the importance of providing affordable energy for rural economic development.

  10. Regulated Noise in the Epigenetic Landscape of Development and Disease

    PubMed Central

    Pujadas, Elisabet; Feinberg, Andrew

    2012-01-01

    In this Perspective, we synthesize past and present observations in the field of epigenetics to propose a model in which the epigenome can modulate cellular plasticity in development and disease by regulating the effects of noise. In this model, the epigenome facilitates phase transitions in development and mediates robustness during cell fate commitment. After grounding our argument in a discussion of stochastic noise and non-genetic heterogeneity, we explore the hypothesis that distinct chromatin domains, which are known to be dysregulated in disease and remodeled during development, might underlie cellular plasticity more generally. We then present a modern portrayal of Waddington's epigenetic landscape through a mathematical formalism. We speculate that this new framework might impact how we approach the unraveling of disease mechanisms. In particular, it may help to explain the observation that the variability of DNA methylation and gene expression are increased in cancer, which leads to tumor cell heterogeneity. PMID:22424224

  11. Validation of BEHAVE fire behavior predictions in oak savannas using five fuel models

    Treesearch

    Keith Grabner; John Dwyer; Bruce Cutter

    1997-01-01

    Prescribed fire is a valuable tool in the restoration and management of oak savannas. BEHAVE, a fire behavior prediction system developed by the United States Forest Service, can be a useful tool when managing oak savannas with prescribed fire. BEHAVE predictions of fire rate-of-spread and flame length were validated using four standardized fuel models: Fuel Model 1 (...

  12. Contributions of woody and herbaceous vegetation to tropical savanna ecosystem productivity: a quasi-global estimate.

    PubMed

    Lloyd, Jon; Bird, Michael I; Vellen, Lins; Miranda, Antonio Carlos; Veenendaal, Elmar M; Djagbletey, Gloria; Miranda, Heloisa S; Cook, Garry; Farquhar, Graham D

    2008-03-01

    To estimate the relative contributions of woody and herbaceous vegetation to savanna productivity, we measured the 13C/12C isotopic ratios of leaves from trees, shrubs, grasses and the surface soil carbon pool for 22 savannas in Australia, Brazil and Ghana covering the full savanna spectrum ranging from almost pure grassland to closed woodlands on all three continents. All trees and shrubs sampled were of the C3 pathway and all grasses of the C4 pathway with the exception of Echinolaena inflexa (Poir.) Chase, a common C3 grass of the Brazilian cerrado. By comparing the carbon isotopic compositions of the plant and carbon pools, a simple model relating soil delta 13C to the relative abundances of trees + shrubs (woody plants) and grasses was developed. The model suggests that the relative proportions of a savanna ecosystem's total foliar projected cover attributable to grasses versus woody plants is a simple and reliable index of the relative contributions of grasses and woody plants to savanna net productivity. Model calibrations against woody tree canopy cover made it possible to estimate the proportion of savanna productivity in the major regions of the world attributable to trees + shrubs and grasses from ground-based observational maps of savanna woodiness. Overall, it was estimated that 59% of the net primary productivity (Np) of tropical savannas is attributable to C4 grasses, but that this proportion varies significantly within and between regions. The C4 grasses make their greatest relative contribution to savanna Np in the Neotropics, whereas in African regions, a greater proportion of savanna Np is attributable to woody plants. The relative contribution of C4 grasses in Australian savannas is intermediate between those in the Neotropics and Africa. These differences can be broadly ascribed to large scale differences in soil fertility and rainfall.

  13. Relationship between tourism development and vegetated landscapes in Luya Mountain Nature Reserve, Shanxi, China.

    PubMed

    Cheng, Zhan-Hong; Zhang, Jin-Tun

    2005-09-01

    The relationship between tourism development and vegetated landscapes is analyzed for the Luya Mountain Nature Reserve (LMNR), Shanxi, China, in this study. Indices such as Sensitive Level (SL), Landscape Importance Value (LIV), information index of biodiversity (H'), Shade-tolerant Species Proportion (SSP), and Tourism Influencing Index (TII) are used to characterize vegetated landscapes, the impact of tourism, and their relationship. Their relationship is studied by Two-Way Indicator Species Analysis (TWINSPAN) and Detrended Correspondence Analysis (DCA). TWINSPAN gives correct and rapid partition to the classification, and DCA ordination shows the changing tendency of all vegetation types based on tourism development. These results reflect the ecological relationship between tourism development and vegetated landscapes. In Luya Mountain Nature Reserve, most plant communities are in good or medium condition, which shows that these vegetated landscapes can support more tourism. However, the occurrence of the bad condition shows that there is a severe contradiction between tourism development and vegetated landscapes.

  14. Cis-regulatory landscapes in development and evolution.

    PubMed

    Maeso, Ignacio; Acemel, Rafael D; Gómez-Skarmeta, José Luis

    2017-04-01

    The recent advances in our understanding of the 3D organization of the chromatin together with an almost unlimited ability to detect cis-regulatory elements genome-wide using different biochemical signatures has provided us with an unprecedented power to study gene regulation. It is now possible to profile the complete regulatory apparatus controlling the spatio-temporal expression of any given gene, the so-called gene Regulatory Landscapes (RLs). Here we review several studies over the last two years demonstrating the functional consequences of altering RL structure in development, disease and evolution. These works clearly show that a deep understanding of transcriptional regulation is no longer conceivable without considering the 3D modular organization of animal genomes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Tissue landscape alters adjacent cell fates during Drosophila egg development

    PubMed Central

    Manning, Lathiena; Weideman, Ann Marie; Peercy, Bradford; Starz-Gaiano, Michelle

    2015-01-01

    Extracellular signaling molecules control many biological processes, but the influence of tissue architecture on the local concentrations of these factors is unclear. Here we examine this issue in the Drosophila egg chamber, where two anterior cells secrete Unpaired (Upd) to activate Signal Transducer and Activator of Transcription (STAT) signaling in the epithelium. High STAT signaling promotes cell motility. Genetic analysis shows that all cells near the Upd source can respond. However, using upright imaging, we show surprising asymmetries in STAT activation patterns, suggesting that some cells experience different Upd levels than predicted by their location. We develop a three-dimensional mathematical model to characterize the spatio-temporal distribution of the activator. Simulations show that irregular tissue domains can produce asymmetric distributions of Upd, consistent with results in vivo. Mutant analysis substantiates this idea. We conclude that cellular landscape can heavily influence the effect of diffusible activators and should be more widely considered. PMID:26082073

  16. Critical Influences on Carbon Balances and Production in the Man-made Montado Savanna of Portugal

    NASA Astrophysics Data System (ADS)

    Pereira, J.; Tenhunen, J.; Dinh, N. Q.; Reichstein, M.; Ribeiro, N.

    2005-12-01

    The "montado savanna" of Portugal provides ecosystem services in the form of cork from Quercus suber trees and understory forage for grazing animals. The production system is controlled directly by physical factors along regional climate and hydrological gradients as well as by human influences on fire, grazing and tree population dynamics (planting and plowing for fire control). We present an analysis of carbon and water exchange at montado savanna sites that is based on long-term eddy covariance measurements, ecophysiological field studies and process-based modelling. A pixel-oriented model set up for spatial simulations, estimates gas fluxes between vegetation and the atmosphere separately for the tree and understory compartments (subsequently combining these), allows for herbage growth and LAI development, and predicts physiological gas exchange restrictions (stomatal regulation) and herb dieback in response to reduced water availability over annual courses. Model validation has been carried out via comparisons with eddy covariance observations at the MITRA II site in Evora, Portugal. Ground level observations of ecosystem structure (LAI and tree cover), aerial photography, Landsat images, and MODIS remotely sensed data are utilized to apply the modelling and to estimate fluxes at landscape, regional and continental scales (Mediterranean basin) for similar vegetation. Potential links to tree growth models and socio-economic models are discussed.

  17. Spatial patterns in the effects of fire on savanna vegetation three-dimensional structure.

    PubMed

    Levick, Shaun R; Asner, Gregory P; Smit, Izak P J

    2012-12-01

    Spatial variability in the effects of fire on savanna vegetation structure is seldom considered in ecology, despite the inherent heterogeneity of savanna landscapes. Much has been learned about the effects of fire on vegetation structure from long-term field experiments, but these are often of limited spatial extent and do not encompass different hillslope catena elements. We mapped vegetation three-dimensional (3-D) structure over 21 000 ha in nine savanna landscapes (six on granite, three on basalt), each with contrasting long-term fire histories (higher and lower fire frequency), as defined from a combination of satellite imagery and 67 years of management records. Higher fire frequency areas contained less woody canopy cover than their lower fire frequency counterparts in all landscapes, and woody cover reduction increased linearly with increasing difference in fire frequency (r2 = 0.58, P = 0.004). Vegetation height displayed a more heterogeneous response to difference in fire frequency, with taller canopies present in the higher fire frequency areas of the wetter sites. Vegetation 3-D structural differences between areas of higher and lower fire frequency differed between geological substrates and varied spatially across hillslopes. Fire had the greatest relative impact on vegetation structure on nutrient-rich basalt substrates, and it imparted different structural responses upon vegetation in upland, midslope, and lowland topographic positions. These results highlight the complexity of fire vegetation relationships in savanna systems, and they suggest that underlying landscape heterogeneity needs more explicit incorporation into fire management policies.

  18. Review of forest landscape models: types, methods, development and applications

    Treesearch

    Weimin Xi; Robert N. Coulson; Andrew G. Birt; Zong-Bo Shang; John D. Waldron; Charles W. Lafon; David M. Cairns; Maria D. Tchakerian; Kier D. Klepzig

    2009-01-01

    Forest landscape models simulate forest change through time using spatially referenced data across a broad spatial scale (i.e. landscape scale) generally larger than a single forest stand. Spatial interactions between forest stands are a key component of such models. These models can incorporate other spatio-temporal processes such as...

  19. Development of spatial database on intact forest landscapes of India

    NASA Astrophysics Data System (ADS)

    Sudhakar Reddy, C.; Singh, Jyoti; Jha, C. S.; Diwakar, P. G.; Dadhwal, V. K.

    2017-01-01

    There is an increased interest in identifying the status of biodiversity in different spatial and temporal scales. The objective of the current research is to prepare a consistent spatial database of intact forest landscapes of India. The intact forest landscapes are located in the Himalayas, Andaman & Nicobar Islands, Western Ghats and Sunderbans. At national level 237 forest landscapes and 5.4% of the total natural forest remained as intact in India. Current intact forest landscapes of India consists of blocks larger than 10 km2 covering an area of 34,061 km2. Of the total area under intact forest landscapes, Eastern Himalayas represent 76.7% of the area, followed by Western Himalayas (8.8%), Andaman & Nicobar Islands (6.2%) and Western Ghats (5.7%). The largest intact forest landscape block occupies an area of 3342.9 km2 (9.8%) is found in western Arunachal Pradesh. Temperate forest zone represents the highest intactness (56.6%), followed by subtropical zone (19.2%), tropical zone (18.6%) and alpine zone (5.6%). Himalayan moist temperate forests represent the highest area (39.1%) of intact forest landscapes followed by subtropical broad-leaved hill forests, wet evergreen forests, and montane wet temperate forests. It is estimated that 4.4% of the area of intact forest landscapes fall inside the existing 47 protected areas. The results of the analysis best suited as input for the process of identification of new protected areas. The study recommends fine-scale mapping of biodiversity within the intact forest landscapes and to prepare efficient conservation plans.

  20. Landscape development in the context of soil distribution in Jordan

    NASA Astrophysics Data System (ADS)

    Lucke, Bernhard

    2016-04-01

    Processes of landscape change can be assessed by studying the distribution of soil types and their connection to climate, the geology, and land use. In this context, even in areas where no virgin soils are available, paleosols pre-dating the introduction of agriculture can be utilized for estimating potential soil development without human impact. Soil distribution in Jordan follows closely the climate and topography: specific soil orders can be found within the dry and hot subtropical, subhumid-semiarid, semiarid-arid, and arid regions. The pattern of soil and paleosol distribution in Jordan points to an important role of the geology (bedrock and relief), and of climate in their formation, both locally such as in the vicinity of the ancient site of Abila, and regionally in the whole country. In contrast, the impact of land use appears relatively limited: overall erosion has been estimated not to exceed the expected geological rate, and Jordan is considered to be in the stable state of completed geologic erosion. This is further supported by strongly varying soil properties and archaeological material on agricultural fields, which suggests that overall erosion processes during historical periods were limited. The presence of a quite uniform 4 m thick loess cover around the site of Umm el-Jimal in north-east Jordan suggests that aeolian deposits are probably the by far dominating parent material of current soils in northern Jordan. In this context, an apparent division of some soil profiles into subsoil and topsoil could correspond to dominant in-situ soil formation out of bedrock weathering at the bottom, while the upper part of the profiles could correspond to aeolian dust as main parent material. A stone line or lithological discontinuity separating these two parts of the profile might refer to a major erosion event. If true, this could indicate that current soils in Jordan might represent a mixture of at least two phases of soil development with probably

  1. Savanna-Bush Environments Research.

    DTIC Science & Technology

    The savanna is a plant formation of tropical regions, comprising a virtually continuous ecologically dominant stratum of more or less xeromorphic plants ... of which herbaceous plants, especially grasses and sedges, are frequently the principal, and occasionally the only, components, although woody

  2. Model development based on a landscape oriented catchment unit concept

    NASA Astrophysics Data System (ADS)

    Cárdenas Gaudry, María.; Gutknecht, Dieter

    2010-05-01

    This paper is a companion paper to our project proposal "Hydrologic model framework for river basins with a range of hydroclimatic and bioclimatic conditions" (HS4.1). It intends to present a few ideas of how to bridge available concepts of landscape classification (as an example the Holdridge Life Zones classification scheme will be used) and hydrological approaches related to the Dominant Process Concept. The focus is on the development of landscape related indices that consider water balance characteristics (e.g.: the relationship ET/P), seasonality measures, and/or runoff generation process signatures at the landscape scale. Methods applied to consider runoff generation in hydrological modelling are commonly based on concepts such as the Hydrological Response Unit (HRU) concept (e.g. Flügel, 1995), the "hydrotop" concept (e.g. Reszler et al., 2006) and the Dominant Runoff Processes concept (DRP, e.g. Schmocker-Fackel and Scherrer, 2007). They are best suited to smaller scale catchment description. It is hypothesized here that additional/new concepts are necessary if the mechanismus that control runoff generation on a larger, i.e. regional scale should be captured. Hydrological reasoning and first results from regional studies indicate that appropiately chosen "signatures" can be found to characterise differences in the control of the runoff processes in different catchments situations. Examples might be "indicators" which include the soil moisture state of a basin or the event runoff coefficient derived from hydrological model simulatons or from runoff observations, respectly (e.g. Samuel et al. 2008; Merz & Blöschl, 2009a). The presentation will demostrate a few results from first studies on the above outlined concept. The study uses data from a set of Austrian catchments prepared for the studies reported in Merz & Blöschl (2009a). References: Flügel, W.-A. (1995): Delineating hydrological response units by geographical information system analyses for

  3. Recent developments in computer modeling add ecological realism to landscape genetics

    EPA Science Inventory

    Background / Question / Methods A factor limiting the rate of progress in landscape genetics has been the shortage of spatial models capable of linking life history attributes such as dispersal behavior to complex dynamic landscape features. The recent development of new models...

  4. Recent developments in computer modeling add ecological realism to landscape genetics

    EPA Science Inventory

    Background / Question / Methods A factor limiting the rate of progress in landscape genetics has been the shortage of spatial models capable of linking life history attributes such as dispersal behavior to complex dynamic landscape features. The recent development of new models...

  5. The ongoing development of a pragmatic and adaptive fire management policy in a large African savanna protected area.

    PubMed

    van Wilgen, Brian W; Govender, Navashni; Smit, Izak P J; MacFadyen, Sandra

    2014-01-01

    This paper describes recent changes to the fire management policy of the 1.9 million ha Kruger National Park in South Africa. It provides a real-life example of adaptive learning in an environment where understanding is incomplete, but where management nonetheless has to proceed. The previous policy called for the application of fire to meet burnt area targets that were set for administrative subdivisions, and that were assessed at the scale of the entire park. This was problematic because the park is large and heterogeneous, and because sound ecological motivations that could link burning prescriptions to ecological objectives were missing. The new policy divides the park into five fire management zones on the basis of differences in mean annual rainfall, historic fire return periods, and geology. In addition, it proposes fire management actions designed to achieve specified ecological objectives in each zone, and includes fire-regime related thresholds and associated ecological outcomes against which to assess the effectiveness of management. The new policy is an improvement over previous iterations, but several challenges remain. Most important among these would be to continually improve the understanding of the effects of fire, and to develop frameworks for assessing the impacts of fire together with other ecosystem drivers that interact strongly with fire to influence the attainment of ecological objectives.

  6. The SLMTA programme: Transforming the laboratory landscape in developing countries

    PubMed Central

    Yao, Katy; Maruta, Talkmore; Luman, Elizabeth T.; Nkengasong, John N.

    2015-01-01

    Background Efficient and reliable laboratory services are essential to effective and well-functioning health systems. Laboratory managers play a critical role in ensuring the quality and timeliness of these services. However, few laboratory management programmes focus on the competencies required for the daily operations of a laboratory in resource-limited settings. This report provides a detailed description of an innovative laboratory management training tool called Strengthening Laboratory Management Toward Accreditation (SLMTA) and highlights some challenges, achievements and lessons learned during the first five years of implementation (2009–2013) in developing countries. Programme SLMTA is a competency-based programme that uses a series of short courses and work-based learning projects to effect immediate and measurable laboratory improvement, while empowering laboratory managers to implement practical quality management systems to ensure better patient care. A SLMTA training programme spans from 12 to 18 months; after each workshop, participants implement improvement projects supported by regular supervisory visits or on-site mentoring. In order to assess strengths, weaknesses and progress made by the laboratory, audits are conducted using the World Health Organization’s Regional Office for Africa (WHO AFRO) Stepwise Laboratory Quality Improvement Process Towards Accreditation (SLIPTA) checklist, which is based on International Organization for Standardization (ISO) 15189 requirements. These internal audits are conducted at the beginning and end of the SLMTA training programme. Conclusion Within five years, SLMTA had been implemented in 617 laboratories in 47 countries, transforming the laboratory landscape in developing countries. To our knowledge, SLMTA is the first programme that makes an explicit connection between the performance of specific management behaviours and routines and ISO 15189 requirements. Because of this close relationship, SLMTA is

  7. Prospects of photon counting lidar for savanna ecosystem structural studies

    NASA Astrophysics Data System (ADS)

    Gwenzi, D.; Lefsky, M. A.

    2014-11-01

    Discrete return and waveform lidar have demonstrated a capability to measure vegetation height and the associated structural attributes such as aboveground biomass and carbon storage. Since discrete return lidar (DRL) is mainly suitable for small scale studies and the only existing spaceborne lidar sensor (ICESat-GLAS) has been decommissioned, the current question is what the future holds in terms of large scale lidar remote sensing studies. The earliest planned future spaceborne lidar mission is ICESat-2, which will use a photon counting technique. To pre-validate the capability of this mission for studying three dimensional vegetation structure in savannas, we assessed the potential of the measurement approach to estimate canopy height in a typical savanna landscape. We used data from the Multiple Altimeter Beam Experimental Lidar (MABEL), an airborne photon counting lidar sensor developed by NASA Goddard. MABEL fires laser pulses in the green (532 nm) and near infrared (1064 nm) bands at a nominal repetition rate of 10 kHz and records the travel time of individual photons that are reflected back to the sensor. The photons' time of arrival and the instrument's GPS positions and Inertial Measurement Unit (IMU) orientation are used to calculate the distance the light travelled and hence the elevation of the surface below. A few transects flown over the Tejon ranch conservancy in Kern County, California, USA were used for this work. For each transect we extracted the data from one near infrared channel that had the highest number of photons. We segmented each transect into 50 m, 25 m and 10 m long blocks and aggregated the photons in each block into a histogram based on their elevation values. We then used an expansion window algorithm to identify cut off points where the cumulative density of photons from the highest elevation resembles the canopy top and likewise where such cumulative density from the lowest elevation resembles mean ground elevation. These cut off

  8. LORICA - A new model for linking landscape and soil profile evolution: Development and sensitivity analysis

    NASA Astrophysics Data System (ADS)

    Temme, Arnaud J. A. M.; Vanwalleghem, Tom

    2016-05-01

    Soils and landscapes evolve in tandem. Landscape position is a strong determinant of vertical soil development, which has often been formalized in the catena concept. At the same time, soil properties are strong determinants of geomorphic processes such as overland erosion, landsliding and creep. We present a new soilscape evolution model; LORICA, to study these numerous interactions between soil and landscape development. The model is based on the existing landscape evolution model LAPSUS and the soil formation model MILESD. The model includes similar soil formation processes as MILESD, but the main novelties include the consideration of more layers and the dynamic adaption of the number of layers as a function of the soil profile's heterogeneity. New processes in the landscape evolution component include a negative feedback of vegetation and armouring and particle size selectivity of the erosion-deposition process. In order to quantify these different interactions, we present a full sensitivity analysis of the input parameters. First results show that the model successfully simulates various soil-landscape interactions, leading to outputs where the surface changes in the landscape clearly depend on soil development, and soil changes depend on landscape location. Sensitivity analysis of the model confirms that soil and landscape interact: variables controlling amount and position of fine clay have the largest effect on erosion, and erosion variables control among others the amount of chemical weathering. These results show the importance of particle size distribution, and especially processes controlling the presence of finer clay particles that are easily eroded, both for the resulting landscape form as for the resulting soil profiles. Further research will have to show whether this is specific to the boundary conditions of this study or a general phenomenon.

  9. Development of a catchment/landscape erosion prediction model (MINErosion 4) for post-mining landscapes in Central Queensland, Australia.

    NASA Astrophysics Data System (ADS)

    Khalifa, Ashraf; Yu, Bofu; Ghadiri, Hossain; Carroll, Chris; So, Hwat-Bing

    2010-05-01

    Open-cut coal mining in Central Queensland involves the breaking up of overburden that overlies the coal seams using explosives, followed by removal with draglines which results in the formation of extensive overburden spoil-piles with steep slopes at the angle of repose (approximately 75 % or 37o). These spoil-piles are found in long multiple rows, with heights of up to 60 or 70 m above the original landscapes. They are generally highly saline and dispersive and hence highly erosive. Legislation requires that these spoil-piles be rehabilitated into a stable self sustaining ecosystem with no off-site pollution. The first stage in the rehabilitation of these landscapes is the lowering of slopes to create a landscape that is stable against geotechnical failure and erosion. This is followed by revegetation generally with grasses as pioneer vegetation to further reduce erosion and a mixture of native shrubs and trees. Minimizing erosion and excessive on-site discharges of sediment into the working areas may result in the temporary cessation of mining operation with significant financial consequences, while off site discharges may breach the mining lease conditions. The average cost of rehabilitation is approximately 22,000 per ha. With more than 50,000 ha of such spoil-piles in Queensland at present, the total cost of rehabilitation facing the industry is very high. Most of this comprised the cost of reshaping the landscape, largely associated with the amount of material movement necessary to achieve the desired landscape. Since soil and spoil-piles vary greatly in their erodibilities, a hillslope erosion model MINErosion 3 (this conference) was developed to determine a cost effective combination of slope length, slope gradient and vegetation that will result in acceptable rates of erosion. This model was useful to determine the design parameters for the construction of a suitable post-mining landscape that meets the required erosion criteria. However, the mining

  10. Developing an ecosystem diversity framework for landscape assessment

    Treesearch

    Robert D. Pfister; Michael D. Sweet

    2000-01-01

    Ecological diversity is being addressed in various research and management efforts, but a common foundation is not explicitly defined or displayed. A formal Ecosystem Diversity Framework (EDF) would improve landscape analysis and communication across multiple scales. The EDF represents a multiple-component vegetation classification system with inherent flexibility for...

  11. EXTINCTION DEBT OF PROTECTED AREAS IN DEVELOPING LANDSCAPES

    EPA Science Inventory

    To conserve biological diversity, protected-area networks must be based not only upon current species distributions but also the landscape's long-term capacity to support populations. We used spatially-explicit population models requiring detailed habitat and demographic data to ...

  12. EXTINCTION DEBT OF PROTECTED AREAS IN DEVELOPING LANDSCAPES

    EPA Science Inventory

    To conserve biological diversity, protected-area networks must be based not only upon current species distributions but also the landscape's long-term capacity to support populations. We used spatially-explicit population models requiring detailed habitat and demographic data to ...

  13. Implications of the spatial dynamics of fire spread for the bistability of savanna and forest.

    PubMed

    Schertzer, E; Staver, A C; Levin, S A

    2015-01-01

    The role of fire in expanding the global distribution of savanna is well recognized. Empirical observations and modeling suggest that fire spread has a threshold response to fuel-layer continuity, which sets up a positive feedback that maintains savanna-forest bistability. However, modeling has so far failed to examine fire spread as a spatial process that interacts with vegetation. Here, we use simple, well-supported assumptions about fire spread as an infection process and its effects on trees to ask whether spatial dynamics qualitatively change the potential for savanna-forest bistability. We show that the spatial effects of fire spread are the fundamental reason that bistability is possible: because fire spread is an infection process, it exhibits a threshold response to fuel continuity followed by a rapid increase in fire size. Other ecological processes affecting fire spread may also contribute including temporal variability in demography or fire spread. Finally, including the potential for spatial aggregation increases the potential both for savanna-forest bistability and for savanna and forest to coexist in a landscape mosaic.

  14. Abandoned pastoral settlements provide concentrations of resources for savanna birds

    NASA Astrophysics Data System (ADS)

    Söderström, Bo; Reid, Robin S.

    2010-03-01

    Knowledge is poor of how fertilization affects birds in grasslands. We investigated the impact on birds of abandoned pastoral settlements that historically received very high levels of livestock dung. A total of 28 abandoned settlements and 74 landscape controls - in Koyake Group Ranch and Maasai Mara National Reserve in Kenya - were surveyed for birds during the wet and/or dry season. Our results showed that bird species richness and total abundance increased within 200 m of abandoned pastoral settlements, particularly during the dry season when foraging resources on the savanna are limited. The high concentrations of nutrients inside abandoned settlements favoured the abundance of Diptera and Coleoptera, as shown by invertebrate surveys performed during the dry season on a subset of 32 sites. Both total numbers and dry biomass of these two invertebrate orders were higher on abandoned settlements in comparison with the surrounding landscape. We conclude that higher fertilization levels cause a temporal and spatial redistribution of birds on the savanna. Livestock fertilization and bird abundance are probably linked through an increase in abundance of invertebrate food upon which birds feed in an opportunistic fashion.

  15. Landscape development during a glacial cycle: modeling ecosystems from the past into the future.

    PubMed

    Lindborg, Tobias; Brydsten, Lars; Sohlenius, Gustav; Strömgren, Mårten; Andersson, Eva; Löfgren, Anders

    2013-05-01

    Understanding how long-term abiotic and biotic processes are linked at a landscape level is of major interest for analyzing future impact on humans and the environment from present-day societal planning. This article uses results derived from multidisciplinary work at a coastal site in Sweden, with the aim of describing future landscape development. First, based on current and historical data, we identified climate change, shoreline displacement, and accumulation/erosion processes as the main drivers of landscape development. Second, site-specific information was combined with data from the Scandinavian region to build models that describe how the identified processes may affect the site development through time. Finally, the process models were combined to describe a whole interglacial period. With this article, we show how the landscape and ecosystem boundaries are affected by changing permafrost conditions, peat formation, sedimentation, human land use, and shoreline displacement.

  16. Spatial pattern enhances ecosystem functioning in an African savanna.

    PubMed

    Pringle, Robert M; Doak, Daniel F; Brody, Alison K; Jocqué, Rudy; Palmer, Todd M

    2010-05-25

    The finding that regular spatial patterns can emerge in nature from local interactions between organisms has prompted a search for the ecological importance of these patterns. Theoretical models have predicted that patterning may have positive emergent effects on fundamental ecosystem functions, such as productivity. We provide empirical support for this prediction. In dryland ecosystems, termite mounds are often hotspots of plant growth (primary productivity). Using detailed observations and manipulative experiments in an African savanna, we show that these mounds are also local hotspots of animal abundance (secondary and tertiary productivity): insect abundance and biomass decreased with distance from the nearest termite mound, as did the abundance, biomass, and reproductive output of insect-eating predators. Null-model analyses indicated that at the landscape scale, the evenly spaced distribution of termite mounds produced dramatically greater abundance, biomass, and reproductive output of consumers across trophic levels than would be obtained in landscapes with randomly distributed mounds. These emergent properties of spatial pattern arose because the average distance from an arbitrarily chosen point to the nearest feature in a landscape is minimized in landscapes where the features are hyper-dispersed (i.e., uniformly spaced). This suggests that the linkage between patterning and ecosystem functioning will be common to systems spanning the range of human management intensities. The centrality of spatial pattern to system-wide biomass accumulation underscores the need to conserve pattern-generating organisms and mechanisms, and to incorporate landscape patterning in efforts to restore degraded habitats and maximize the delivery of ecosystem services.

  17. A Crown Cover Chart for Oak Savannas

    Treesearch

    Jay Law; Paul Johnson; Gary Houf

    1994-01-01

    Although oak savannas have been defined in many ways, they are characterized by scattered trees, largely comprised of oaks, and a sparse ground layer rich in grasses and forbs (Haney and Apfelbaum 1990). Nuzzo (1986, p. 11) more specifically defined oak savannas as plant communities "...dominated by oaks having between 10 and 80 percent canopy, with or without a...

  18. Forest landscape analysis and design: a process for developing and implementing land management objectives for landscape patterns.

    Treesearch

    Nancy Diaz; Dean. Apostol

    1992-01-01

    This publication presents a Landscape Design and Analysis Process, along with some simple methods and tools for describing landscapes and their function. The information is qualitative in nature and highlights basic concepts, but does not address landscape ecology in great depth. Readers are encouraged to consult the list of selected references in Chapter 2 if they...

  19. An overview of nitrogen cycling in a semiarid savanna: some implications for management and conservation in a large African park.

    PubMed

    Coetsee, Corli; Jacobs, Shayne; Govender, Navashni

    2012-02-01

    Nitrogen (N) is a major control on primary productivity and hence on the productivity and diversity of secondary producers and consumers. As such, ecosystem structure and function cannot be understood without a comprehensive understanding of N cycling and dynamics. This overview describes the factors that govern N distribution and dynamics and the consequences that variable N dynamics have for structure, function and thresholds of potential concern (TPCs) for management of a semiarid southern African savanna. We focus on the Kruger National Park (KNP), a relatively intact savanna, noted for its wide array of animal and plant species and a prized tourist destination. KNP's large size ensures integrity of most ecosystem processes and much can be learned about drivers of ecosystem structure and function using this park as a baseline. Our overview shows that large scale variability in substrates exists, but do not necessarily have predictable consequences for N cycling. The impact of major drivers such as fire is complex; at a landscape scale little differences in stocks and cycling were found, though at a smaller scale changes in woody cover can lead to concomitant changes in total N. Contrasting impacts of browsers and grazers on N turnover has been recorded. Due to the complexity of this ecosystem, we conclude that it will be complicated to draw up TPCs for most transformations and pools involved with the N cycle. However, we highlight in which cases the development of TPCs will be possible.

  20. An Overview of Nitrogen Cycling in a Semiarid Savanna: Some Implications for Management and Conservation in a Large African Park

    NASA Astrophysics Data System (ADS)

    Coetsee, Corli; Jacobs, Shayne; Govender, Navashni

    2012-02-01

    Nitrogen (N) is a major control on primary productivity and hence on the productivity and diversity of secondary producers and consumers. As such, ecosystem structure and function cannot be understood without a comprehensive understanding of N cycling and dynamics. This overview describes the factors that govern N distribution and dynamics and the consequences that variable N dynamics have for structure, function and thresholds of potential concern (TPCs) for management of a semiarid southern African savanna. We focus on the Kruger National Park (KNP), a relatively intact savanna, noted for its wide array of animal and plant species and a prized tourist destination. KNP's large size ensures integrity of most ecosystem processes and much can be learned about drivers of ecosystem structure and function using this park as a baseline. Our overview shows that large scale variability in substrates exists, but do not necessarily have predictable consequences for N cycling. The impact of major drivers such as fire is complex; at a landscape scale little differences in stocks and cycling were found, though at a smaller scale changes in woody cover can lead to concomitant changes in total N. Contrasting impacts of browsers and grazers on N turnover has been recorded. Due to the complexity of this ecosystem, we conclude that it will be complicated to draw up TPCs for most transformations and pools involved with the N cycle. However, we highlight in which cases the development of TPCs will be possible.

  1. Plot-level aboveground woody biomass modeling using canopy height and auxiliary remote sensing data in a heterogeneous savanna

    NASA Astrophysics Data System (ADS)

    Gwenzi, David; Lefsky, Michael Andrew

    2016-01-01

    Remote sensing studies aiming at assessing woody biomass have demonstrated a strong relationship between canopy height and plot-level aboveground biomass, but most of these studies focused on closed canopy forests. To date, a few studies have examined the strength and reliability of this relationship using large footprint lidar in savannas. Furthermore, there have been few studies of appropriate methods for the comparison of models that relate aboveground biomass to canopy height metrics without consideration of variation in species composition (generic models) to models developed for individual species composition or vegetation types. We developed generic models using the classical least-squares regression modeling approach to relate selected canopy height metrics to aboveground woody biomass in a savanna landscape. Hierarchical Bayesian analysis (HBA) was then used to explore the implications of using generic or composition-specific models. Our study used the estimates of aboveground biomass from field data, canopy height estimates from airborne discrete return lidar, and a proxy for canopy cover (the Normalized Difference Vegetation Index) from Landsat 5 Thematic Mapper data, collected from the oak savannas of Tejon Ranch Conservancy in Kern County, California. Models were developed and analyzed using estimates of canopy height and aboveground biomass calculated at the level of 50-m diameter plots, comparable with footprint diameter of existing large footprint spaceborne lidar data. The two generic models that incorporated canopy cover proxies performed better than one model that did not use canopy cover information. From the HBA, we found out that for all models both the intercept and slope had interspecific variability. The valley oak dominated plots consistently had higher slopes and intercepts, whereas the plots dominated by blue oaks had the lowest. However, the intercept and slope values of the composition-specific models did not differ much from the

  2. Forecasting spatial plant dynamics under future climate change in a semiarid savanna ecosystem with complex topography

    NASA Astrophysics Data System (ADS)

    Zhou, X.; Fatichi, S.; Istanbulluoglu, E.; Vivoni, E. R.

    2011-12-01

    The space and time dynamics of savanna ecosystems in semiarid regions is tightly related to fluctuations and changes in the climate, and the competition strategies of individual plants for resources. In most parts of the southwest U.S., various General Circulation Models (GCMs) predict general warming trends with reduced annual precipitation amounts, and increased frequency of extreme droughts and wet periods in the 21st century. Despite the potential risks posed by climate change on vegetation patterns and hydrology, our ability to predict such changes at the catchment and regional scales is limited. In this study, we used a recently developed spatially explicit Cellular Automata Tree-Grass-Shrub Simulator (CATGraSS) to investigate the impacts of climate change on plant dynamics in a semiarid catchment (>3km2) located in the Sevilleta National Wildlife Refuge (SNWR) in central New Mexico, USA. In the catchment north-facing slopes are characterized by a juniper-grass savanna, and south-facing slopes by creosote bush and grass species. Initialized by LIDAR-derived tree locations and simulated grass and shrub patterns obtained from model calibration, CATGraSS is forced by a weather generator, AWE-GEN, used to downscale an ensemble of eight different GCM outputs at the study basin, producing multiple stochastic realizations of a transient climate scenario for the next hundred years. The ensemble simulations are used to examine the uncertainty in vegetation response and develop probabilistic plant distribution maps in relation to landscape morphology. This study highlights the importance of understanding local scale plant-to-plant interactions and the role of climate variability in determining climate change impacts on vegetation dynamics at varying spatial scales.

  3. Patterns in woody vegetation structure across African savannas

    NASA Astrophysics Data System (ADS)

    Axelsson, Christoffer R.; Hanan, Niall P.

    2017-07-01

    Vegetation structure in water-limited systems is to a large degree controlled by ecohydrological processes, including mean annual precipitation (MAP) modulated by the characteristics of precipitation and geomorphology that collectively determine how rainfall is distributed vertically into soils or horizontally in the landscape. We anticipate that woody canopy cover, crown density, crown size, and the level of spatial aggregation among woody plants in the landscape will vary across environmental gradients. A high level of woody plant aggregation is most distinct in periodic vegetation patterns (PVPs), which emerge as a result of ecohydrological processes such as runoff generation and increased infiltration close to plants. Similar, albeit weaker, forces may influence the spatial distribution of woody plants elsewhere in savannas. Exploring these trends can extend our knowledge of how semi-arid vegetation structure is constrained by rainfall regime, soil type, topography, and disturbance processes such as fire. Using high-spatial-resolution imagery, a flexible classification framework, and a crown delineation method, we extracted woody vegetation properties from 876 sites spread over African savannas. At each site, we estimated woody cover, mean crown size, crown density, and the degree of aggregation among woody plants. This enabled us to elucidate the effects of rainfall regimes (MAP and seasonality), soil texture, slope, and fire frequency on woody vegetation properties. We found that previously documented increases in woody cover with rainfall is more consistently a result of increasing crown size than increasing density of woody plants. Along a gradient of mean annual precipitation from the driest (< 200 mm yr-1) to the wettest (1200-1400 mm yr-1) end, mean estimates of crown size, crown density, and woody cover increased by 233, 73, and 491 % respectively. We also found a unimodal relationship between mean crown size and sand content suggesting that maximal

  4. Savanna burning methodology for fire management and emissions reduction: a critical review of influencing factors.

    PubMed

    Maraseni, Tek Narayan; Reardon-Smith, Kathryn; Griffiths, Greg; Apan, Armando

    2016-12-01

    Savanna fire is a major source of global greenhouse gas (GHG) emissions. In Australia, savanna fire contributes about 3% of annual GHG emissions reportable to the Kyoto Protocol. In order to reduce GHG emissions from savanna burning, the Australian government has developed and approved a Kyoto compliant savanna controlled burning methodology-the first legal instrument of this kind at a global level-under its Emission Reduction Fund. However, this approved methodology is currently only applicable to nine vegetation fuel types across northern parts of Australia in areas which receive on average over 600 mm rainfall annually, covering only 15.4% of the total land area in Australia. Savanna ecosystems extend across a large proportion of mainland Australia. This paper provides a critical review of ten key factors that need to be considered in developing a savanna burning methodology applicable to the other parts of Australia. It will also inform discussion in other countries intent on developing similar emissions reduction strategies.

  5. Nesting success of grassland and savanna birds on reclaimed surface coal mines of the midwestern United States

    SciTech Connect

    Galligan, E.W.; DeVault, T.L.; Lima, S.L.

    2006-12-15

    Reclaimed surface coal mines in southwestern Indiana support many grassland and shrub/savanna bird species of conservation concern. We examined the nesting success of birds on these reclaimed mines to assess whether such 'unnatural' places represent productive breeding habitats for such species. We established eight study sites on two large, grassland-dominated mines in southwestern Indiana and classified them into three categories (open grassland, shrub/savanna, and a mixture of grassland and shrub/savanna) based on broad vegetation and landscape characteristics. During the 1999 and 2000 breeding seasons, we found and monitored 911 nests of 31 species. Daily nest survival for the most commonly monitored grassland species ranged from 0.903 (Dickcissel, Spiza americana) to 0.961 (Grasshopper Sparrow, Ammodramus savannarum). Daily survival estimates for the dominant shrub/savanna nesting species ranged from 0.932 (Brown Thrasher, Toxostoma rufum) to 0.982 (Willow Flycatcher, Empidonax traillii). Vegetation and landscape effects on nesting success were minimal, and only Eastern Meadowlarks (Sturnella magna) showed a clear time-of-season effect, with greater nesting success in the first half of the breeding season. Rates of Brown-headed Cowbird (Molothrus ater) parasitism were only 2.1% for grassland species and 12.0% for shrub/savanna species. The nesting success of birds on reclaimed mine sites was comparable to that in other habitats, indicating that reclaimed habitats on surface mines do not necessarily represent reproductive traps for birds.

  6. Development of a Shoreline Environmental Impact Index (SEII): An analysis of landscape pattern and structure metrics

    NASA Astrophysics Data System (ADS)

    Jackson, Mark Wadley

    The goal of this study was to develop a Shoreline Environmental Impact Index (SEII) based upon landscape ecology pattern and structure metrics calculated from high resolution remotely sensed imagery This SEII would provide a tool for monitoring freshwater lakes and reservoirs in areas of rapid development. The land use/land cover information for the study was derived from National Aerial Photography Program (NAPP) imagery of a portion of Lake Murray, South Carolina shoreline scanned to simulate high resolution remotely sensed imagery. The shoreline in the study area was divided into 400 landscape units. Common landscape ecology metrics were calculated for these landscape units. They were also rated on a scale from 1 to 10 by expert visual interpretation with a rating of 1 indicating no environmental impact and 10 meaning the shoreline had been severely impacted and was in need of in situ monitoring. Factor analysis of the landscape metrics calculated support previous work indicating a small number of independent, orthogonal factors are being measured by the landscape metrics (Riitters et al., 1995, Cain et al., 1997). Methods of combining landscape ecology metrics to create a meaningful Shoreline Environmental Impact Index (SEII) included multiple linear regression, multiple discriminant analysis, genetic neural networks, standard feed forward back propagation neural networks and manual combination. The ratings produced by the SEII's generated using these methods were then compared to the ratings by the experts. There was very little difference in the performance of several SEII's generated despite some differences in metrics and weighting chosen by the different methods. The ratings from all methods showed their ability to reflect the expert ratings in general. Conclusions indicate that the ability of the landscape metrics to discriminate between levels of shoreline degradation is contained within a relatively few metrics. In any of the current forms the SEII is

  7. Implementing landscape fragmentation as an indicator in the Swiss Monitoring System Of Sustainable Development (Monet).

    PubMed

    Jaeger, Jochen A G; Bertiller, René; Schwick, Christian; Müller, Kalin; Steinmeier, Charlotte; Ewald, Klaus C; Ghazoul, Jaboury

    2008-09-01

    There is an increasing need and interest in including indicators of landscape fragmentation in monitoring systems of sustainable landscape management. Landscape fragmentation due to transportation infrastructure and urban development threatens human and environmental well-being by noise and pollution from traffic, reducing the size and viability of wildlife populations, facilitating the spread of invasive species, and impairing the scenic and recreational qualities of the landscape. This paper provides the rationale, method, and data for including landscape fragmentation in monitoring systems, using as an example the Swiss Monitoring System of Sustainable Development (Monet). We defined and compared four levels of fragmentation analysis, or fragmentation geometries (FGs), each based on different fragmenting elements, e.g., only anthropogenic, or combinations of anthropogenic and natural elements. As each FG has specific strengths and weaknesses, the most appropriate choice of FG depends on the context and objectives of a study. We present data on the current degree of landscape fragmentation for the five ecoregions and 26 cantons in Switzerland for all four FGs. Our results show that the degree of landscape fragmentation as quantified by the effective mesh size method is strongly supported by the postulates and indicator selection criteria of Monet, and we identify the most suitable FG focusing on the land area below 2,100 m (e.g., excluding lakes) and allowing for an equitable comparison of fragmentation degrees among regions that differ in area covered by lakes and high mountains. For a more detailed analysis of landscape fragmentation in the context of environmental impact assessments and strategic environmental assessments, a combination of all four FGs may provide a more informative tool than any single FG.

  8. Impact of savanna conversion to oil palm plantations on C stocks dynamics and soil fertility

    NASA Astrophysics Data System (ADS)

    Quezada, Juan Carlos; Guillaume, Thomas; Buttler, Alexandre; Ruegg, Johanna

    2017-04-01

    Large-scale expansion of oil palm cultivation on forested land in South-East Asia during the last decades lead to high negative environmental impacts. Because rainforests store high amount of C, their conversion to oil palm plantations results in large net CO2 emissions. Oil palm cultivation in tropical ecosystems such as savanna that store less C than forests is seen as an alternative to reduce greenhouse gas emissions of future oil palm development. While this option is more and more frequently mentioned, few data are available on the effective gain in C storage. Furthermore negative impact on soil organic carbon and soil fertility could offset gains of C storage in oil palm biomass. Here, we present results on aboveground and belowground C stocks and soil nutrient dynamics over a full rotation cycle of oil palm plantations established on tropical savanna grasslands. Three natural savanna grasslands as reference sites and 9 oil palm plantations ranging from two to twenty-seven years old were selected in the Llanos in Colombia. Oxisols were sampled down to 70 cm in each management zones of oil palm plantations (weeded circle, interrow, frond piles and harvesting path). Taking advantages of a shift from C4 to C3 vegetation, we quantified savanna-derived soil organic carbon (SOC) decomposition and oil palm-derived SOC stabilization rates and how they were affected by management practices (mineral fertilization, organic amendments, etc.). Results show that, in opposite to forest conversion, C storage increases when savannas are converted to oil palm plantations. Because soil C storage was very low in natural conditions, SOC changes had little effects on overall C storage. Substitution of savanna-derived SOC by oil palm-derived SOC was very fast in the topsoil and highest under frond pile and weeded circle where C and nutrients inputs are highest. However, stabilization of oil palm-derived SOC compensated loss of savanna-derived SOC rather than increased SOC stocks

  9. The characterisation and management of greenhouse gas emissions from fires in northern Australian savannas

    NASA Astrophysics Data System (ADS)

    Cook, G. D.; Liedloff, A. C.; Richards, A. E.; Meyer, M.

    2016-12-01

    Australia is the only OECD country with a significant area of tropical savannas within it borders. Approximately 220 000 km2 of these savannas burn every year releasing 2 to 4 % of Australia's accountable greenhouse gas emissions. Reduction in uncertainty in the quantification of these emissions of methane and nitrous has been fundamental to improving both the national GHG inventory and developing approaches to better manage land to reduce these emissions. Projects to reduce pyrogenic emissions have been adopted across 30% of Australia's high rainfall savannas. Recent work has focussed on quantifying the additional benefit of increased carbon stocks in fine fuel and coarse woody debris (CWD) resulting from improvements in fire management. An integrated set of equations have been developed to enable seemless quantification of emissions and sequestration in these frequently burnt savannas. These show that increases in carbon stored in fine fuel and CWD comprises about 3 times the emissions abatement from improvements in fire management that have been achieved in a project area of 28 000 km2. Future work is focussing on improving the understanding of spatial and temporal variation in fire behaviour across Australia's savanna biome, improvements in quantification of carbon dynamics of CWD and improved quantification of the effects of fire on carbon dynamics in soils of the savannas.

  10. Long-term variability and rainfall control of savanna fire regimes in equatorial East Africa.

    PubMed

    Nelson, David M; Verschuren, Dirk; Urban, Michael A; Hu, Feng Sheng

    2012-10-01

    Fires burning the vast grasslands and savannas of Africa significantly influence the global carbon cycle. Projecting the impacts of future climate change on fire-mediated biogeochemical processes in these dry tropical ecosystems requires understanding of how various climate factors influence regional fire regimes. To examine climate-vegetation-fire linkages in dry savanna, we conducted macroscopic and microscopic charcoal analysis on the sediments of the past 25 000 years from Lake Challa, a deep crater lake in equatorial East Africa. The charcoal-inferred shifts in local and regional fire regimes were compared with previously published reconstructions of temperature, rainfall, seasonal drought severity, and vegetation dynamics to evaluate millennial-scale drivers of fire occurrence. Our charcoal data indicate that fire in the dry lowland savanna of southeastern Kenya was not fuel-limited during the Last Glacial Maximum (LGM) and Late Glacial, in contrast to many other regions throughout the world. Fire activity remained high at Lake Challa probably because the relatively high mean-annual temperature (~22 °C) allowed productive C4 grasses with high water-use efficiency to dominate the landscape. From the LGM through the middle Holocene, the relative importance of savanna burning in the region varied primarily in response to changes in rainfall and dry-season length, which were controlled by orbital insolation forcing of tropical monsoon dynamics. The fuel limitation that characterizes the region's fire regime today appears to have begun around 5000-6000 years ago, when warmer interglacial conditions coincided with prolonged seasonal drought. Thus, insolation-driven variation in the amount and seasonality of rainfall during the past 25 000 years altered the immediate controls on fire occurrence in the grass-dominated savannas of eastern equatorial Africa. These results show that climatic impacts on dry-savanna burning are heterogeneous through time, with

  11. Forests, savannas, and grasslands: bridging the knowledge gap between ecology and Dynamic Global Vegetation Models

    NASA Astrophysics Data System (ADS)

    Baudena, M.; Dekker, S. C.; van Bodegom, P. M.; Cuesta, B.; Higgins, S. I.; Lehsten, V.; Reick, C. H.; Rietkerk, M.; Scheiter, S.; Yin, Z.; Zavala, M. A.; Brovkin, V.

    2015-03-01

    The forest, savanna, and grassland biomes, and the transitions between them, are expected to undergo major changes in the future due to global climate change. Dynamic global vegetation models (DGVMs) are very useful for understanding vegetation dynamics under the present climate, and for predicting its changes under future conditions. However, several DGVMs display high uncertainty in predicting vegetation in tropical areas. Here we perform a comparative analysis of three different DGVMs (JSBACH, LPJ-GUESS-SPITFIRE and aDGVM) with regard to their representation of the ecological mechanisms and feedbacks that determine the forest, savanna, and grassland biomes, in an attempt to bridge the knowledge gap between ecology and global modeling. The outcomes of the models, which include different mechanisms, are compared to observed tree cover along a mean annual precipitation gradient in Africa. By drawing on the large number of recent studies that have delivered new insights into the ecology of tropical ecosystems in general, and of savannas in particular, we identify two main mechanisms that need improved representation in the examined DGVMs. The first mechanism includes water limitation to tree growth, and tree-grass competition for water, which are key factors in determining savanna presence in arid and semi-arid areas. The second is a grass-fire feedback, which maintains both forest and savanna presence in mesic areas. Grasses constitute the majority of the fuel load, and at the same time benefit from the openness of the landscape after fires, since they recover faster than trees. Additionally, these two mechanisms are better represented when the models also include tree life stages (adults and seedlings), and distinguish between fire-prone and shade-tolerant forest trees, and fire-resistant and shade-intolerant savanna trees. Including these basic elements could improve the predictive ability of the DGVMs, not only under current climate conditions but also and

  12. Tropical Forests, Savannas and Grasslands: Bridging the Knowledge Gap Between Ecology and Dynamic Global Vegetation Models

    NASA Astrophysics Data System (ADS)

    Baudena, M.; Dekker, S. C.; van Bodegom, P. M.; Cuesta, B.; Higgins, S. I.; Lehsten, V.; Reick, C. H.; Rietkerk, M.; Scheiter, S.; Yin, Z.; Zavala, M. A.; Brovkin, V.

    2014-12-01

    Due to global climate change, tropical forest, savanna, and grassland biomes, and the transitions between them, are expected to undergo major changes in the future. Dynamic Global Vegetation Models (DGVMs) are largely used to understand vegetation dynamics under present climate, and to predict its changes under future conditions. However, several DGVMs display high uncertainty in predicting vegetation in tropical areas. Here we present the results of a comparative analysis of three different DGVMs (JSBACH, LPJ-GUESS-SPITFIRE and aDGVM) with regard to their different representations of the ecological mechanisms and feedbacks that determine the forest, savanna and grassland biomes, in an attempt to bridge the knowledge gap between ecology and global modelling. We compared model outcomes to observed tree cover along a mean annual precipitation gradient in Africa. Through these comparisons, and by drawing on the large number of recent studies that have delivered new insights into the ecology of tropical ecosystems in general, and of savannas in particular, we identify two main mechanisms that need an improved representation in the DGVMs. The first mechanism encompasses water limitation to tree growth, and tree-grass competition for water, which are key factors in determining savanna occurrence in arid and semi-arid areas. The second is a grass-fire feedback, which maintains both forest and savannas in mesic areas. Grasses constitute the majority of the fuel load, and at the same time benefit from the openness of the landscape after fires, since they recover faster than trees. Additionally, these two mechanisms are better represented when the models also include tree life stages (adults and seedlings), and distinguish between fire-prone and shade-tolerant savanna trees, and fire-resistant and shade-intolerant forest trees. Including these basic elements could improve the predictive ability of the DGVMs, not only under current climate conditions but also and especially

  13. Using remote sensing and biogeographic modeling to understand the oak savannas of the Sheyenne National Grassland, North Dakota, USA

    NASA Astrophysics Data System (ADS)

    SigdelPhuyal, Mandira

    Oak savannas are valuable and complex ecosystems that provide multiple ecosystem goods and services, including grazing for livestock, watershed regulation, and recreation. These ecosystems of the woodland-prairie ecoregion of the Midwestern United States are, however, in danger of disappearing. The Sheyenne National Grassland, North Dakota, a protected Prairie grassland-savanna, is a representative of such rare habitats, where oak savanna is found at the landscape scale. In this research, I map the distribution patterns of oak savanna in the Sheyenne using a combination of remote sensing and geospatial datasets, including landscape topography, soils, and fire disturbance. Further, I interpret the performance of a suite of advanced Species Distribution Modeling approaches including Maximum Entropy, Random Forest, Generalized Boosted Model, and Classification Tree to analyze the primary environmental and management factors influencing oak distributions at landscape scales. Woody canopy cover was estimated with high classification accuracy (80-95%) for two study areas of the Sheyenne National Grassland. Among the four species distribution modeling approaches tested, the Random Forest (RF) approach provided the best predictive model. RF model parameters indicate that oak trees favor gently sloping locations, on well-drained upland and sandy soils, with north-facing aspect. While no direct data on water relationships were possible in this research, the importance of the topographic and soil variables in the SDM presumably reflect oak preference for locations and soils that are not prone to water saturation, with milder summer temperatures (i.e. northern aspects), providing conditions suitable for seedling establishment and growth. This research increases our understanding of the biogeography of Midwestern tall-grass oak savannas and provides a decision-support tool for oak savanna management.

  14. Mapping Brazilian savanna vegetation gradients with Landsat time series

    NASA Astrophysics Data System (ADS)

    Schwieder, Marcel; Leitão, Pedro J.; da Cunha Bustamante, Mercedes Maria; Ferreira, Laerte Guimarães; Rabe, Andreas; Hostert, Patrick

    2016-10-01

    Global change has tremendous impacts on savanna systems around the world. Processes related to climate change or agricultural expansion threaten the ecosystem's state, function and the services it provides. A prominent example is the Brazilian Cerrado that has an extent of around 2 million km2 and features high biodiversity with many endemic species. It is characterized by landscape patterns from open grasslands to dense forests, defining a heterogeneous gradient in vegetation structure throughout the biome. While it is undisputed that the Cerrado provides a multitude of valuable ecosystem services, it is exposed to changes, e.g. through large scale land conversions or climatic changes. Monitoring of the Cerrado is thus urgently needed to assess the state of the system as well as to analyze and further understand ecosystem responses and adaptations to ongoing changes. Therefore we explored the potential of dense Landsat time series to derive phenological information for mapping vegetation gradients in the Cerrado. Frequent data gaps, e.g. due to cloud contamination, impose a serious challenge for such time series analyses. We synthetically filled data gaps based on Radial Basis Function convolution filters to derive continuous pixel-wise temporal profiles capable of representing Land Surface Phenology (LSP). Derived phenological parameters revealed differences in the seasonal cycle between the main Cerrado physiognomies and could thus be used to calibrate a Support Vector Classification model to map their spatial distribution. Our results show that it is possible to map the main spatial patterns of the observed physiognomies based on their phenological differences, whereat inaccuracies occurred especially between similar classes and data-scarce areas. The outcome emphasizes the need for remote sensing based time series analyses at fine scales. Mapping heterogeneous ecosystems such as savannas requires spatial detail, as well as the ability to derive important

  15. Hydraulic lift as a determinant of tree-grass coexistence on savannas.

    PubMed

    Yu, Kailiang; D'Odorico, Paolo

    2015-09-01

    The coexistence of woody plants and grasses in savannas is determined by a complex set of interacting factors that determine access to resources and demographic dynamics, under the control of external drivers and vegetation feedbacks with the physical environment. Existing theories explain coexistence mainly as an effect of competitive relations and/or disturbances. However, theoretical studies on the way facilitative interactions resulting from hydraulic lift affect tree-grass coexistence and the range of environmental conditions in which savannas are stable are still lacking. We investigated the role of hydraulic lift in the stability of tree-grass coexistence in savannas. To that end, we developed a new mechanistic model that accounts for both competition for soil water in the shallow soil and fire-induced disturbance. We found that hydraulic lift favors grasses, which scavenge the water lifted by woody plants. Thus, hydraulic lift expands (at the expenses of woodlands) the range of environmental conditions in which savannas are stable. These results indicate that hydraulic lift can be an important mechanism responsible for the coexistence of woody plants and grasses in savannas. Grass facilitation by trees through the process of hydraulic lift could allow savannas to persist stably in mesic regions that would otherwise exhibit a forest cover.

  16. Overdeepening development in a glacial landscape evolution model with quarrying

    NASA Astrophysics Data System (ADS)

    Ugelvig, S. V.; Egholm, D. L.; Brædstrup, C. F.; Iverson, N. R.

    2013-12-01

    In glacial landscape evolution models, subglacial erosion rates are often related to basal sliding or ice discharge by a power-law. This relation can be justified when considering bed abrasion, where rock debris transported in the basal ice drives erosion. However, the relation is not well supported when considering models for quarrying of rock blocks from the bed. Field observations indicate that the principal mechanism of glacial erosion is quarrying, which emphasize the importance of a better way of implementing erosion by quarrying in glacial landscape evolution models. Iverson (2012) introduced a new model for subglacial erosion by quarrying that operates from the theory of adhesive wear. The model is based on the fact that cavities, with a high level of bedrock differential stress, form in the lee of bed obstacles when the sliding velocity is too high to allow for the ice to creep around the obstacles. The erosion rate is quantified by considering the likelihood of rock fracturing on topographic bumps. The model includes a statistical treatment of the bedrock weakness, which is neglected in previous quarrying models. Sliding rate, effective pressure, and average bedslope are the primary factors influencing the erosion rate of this new quarrying model [Iverson, 2012]. We have implemented the quarrying model in a depth-integrated higher-order ice-sheet model [Egholm et al. 2011], coupled to a model for glacial hydrology. In order to also include the effects of cavitation on the subglacial sliding rate, we use a sliding law proposed by Schoof (2005), which includes an upper limit for the stress that can be supported at the bed. Computational experiments show that the combined influence of pressure, sliding rate and bed slope leads to realistically looking landforms such as U-shaped valleys, cirques, hanging valleys and overdeepenings. The influence of the effective pressure leads naturally to overdeepenings. However, in contrast to previously used erosion models

  17. Effects of exurban development on trophic interactions in a desert landscape

    USDA-ARS?s Scientific Manuscript database

    Context Mechanisms of ecosystem change in urbanizing landscapes are poorly understood, especially in exurban areas featuring residential or commercial development set in a matrix of modified and natural vegetation. We asked how development altered trophic interactions and ecosystem processes in the ...

  18. Design-with-nature for multifunctional landscapes: environmental benefits and social barriers in community development.

    PubMed

    Yang, Bo; Li, Ming-Han; Li, Shujuan

    2013-10-28

    Since the early 1970s, Ian McHarg's design-with-nature concept has been inspiring landscape architects, community and regional planners, and liked-minded professionals to create designs that take advantage of ecosystem services and promote environmental and public health. This study bridges the gap in the literature that has resulted from a lack of empirical examinations on the multiple performance benefits derived through design-with-nature and the under-investigated social aspect emanated from McHarg's Ecological Determinism design approach. The Woodlands, TX, USA, an ecologically designed community development under McHarg's approach, is compared with two adjacent communities that follow the conventional design approach. Using national environmental databases and multiple-year residents' survey information, this study assesses three landscape performance metrics of McHarg's approach: stormwater runoff, urban heat island effect, and social acceptance. Geographic Information Systems (GIS) was used to assess the development extent and land surface temperature distribution. Results show that McHarg's approach demonstrates benefits in reducing runoff and urban heat island effect, whereas it confronts challenges with the general acceptance of manicured landscapes and thus results in a low safety perception level when residents interact with naturally designed landscapes. The authors argue that design-with-nature warrants multifunctionality because of its intrinsic interdisciplinary approach. Moreover, education and dissemination of successful examples can achieve a greater level of awareness among the public and further promote multifunctional design for landscape sustainability.

  19. Design-with-Nature for Multifunctional Landscapes: Environmental Benefits and Social Barriers in Community Development

    PubMed Central

    Yang, Bo; Li, Ming-Han; Li, Shujuan

    2013-01-01

    Since the early 1970s, Ian McHarg’s design-with-nature concept has been inspiring landscape architects, community and regional planners, and liked-minded professionals to create designs that take advantage of ecosystem services and promote environmental and public health. This study bridges the gap in the literature that has resulted from a lack of empirical examinations on the multiple performance benefits derived through design-with-nature and the under-investigated social aspect emanated from McHarg’s Ecological Determinism design approach. The Woodlands, TX, USA, an ecologically designed community development under McHarg’s approach, is compared with two adjacent communities that follow the conventional design approach. Using national environmental databases and multiple-year residents’ survey information, this study assesses three landscape performance metrics of McHarg’s approach: stormwater runoff, urban heat island effect, and social acceptance. Geographic Information Systems (GIS) was used to assess the development extent and land surface temperature distribution. Results show that McHarg’s approach demonstrates benefits in reducing runoff and urban heat island effect, whereas it confronts challenges with the general acceptance of manicured landscapes and thus results in a low safety perception level when residents interact with naturally designed landscapes. The authors argue that design-with-nature warrants multifunctionality because of its intrinsic interdisciplinary approach. Moreover, education and dissemination of successful examples can achieve a greater level of awareness among the public and further promote multifunctional design for landscape sustainability. PMID:24169408

  20. Landscape ecological assessment and eco-tourism development in the South Dongting Lake Wetland, China.

    PubMed

    He, Ping; Wang, Bao-zhong

    2003-03-01

    As an important resource and the living environment of mankind, wetland has become gradually a highlight, strongly concerned and intensively studied by scientists and sociologists. The governments in the world and the whole society have been paying more and more attention on it. The Dongting Lake of China is regarded as an internationally important wetland. For a rational development and protection of the wetland, an investigation and studied on its resources and its value to tourism in the South Dongting Lake was conducted, to create an assessment system of the ecological landscapes, and to evaluate qualitatively and quantitatively the value of wetland landscape to the ecotourism. The results showed that the scenic value of the South Dongting Lake Wetland satisfied the criterion of AAAA grade of China national scenic attraction. The eco-tourism value of the landscape cultures in the South Dongting Lake Wetland was discussed with emphasis. It were formulated that a principle and frame of sustainable exploitation of the wetland landscapes and it was proposed as well that establishing a Wetland Park and developing eco-tourism in the South Dongting Lake Wetland is a fragile ecosystem with low resistance to the impact of the exploitation. Thus, we must pay intensively attention to the influence of exploitation on the landscape, take the ecological risk in account to employ a right countermeasure and avoid the negative affection.

  1. New concept of aging care architecture landscape design based on sustainable development

    NASA Astrophysics Data System (ADS)

    Xu, Ying

    2017-05-01

    As the aging problem becoming serious in China, Aging care is now one of the top issuer in front of all of us. Lots of private and public aging care architecture and facilities have been built. At present, we only pay attention to the architecture design and interior design scientific, ecological and sustainable design on aged care architecture landscape. Based on the social economy, population resources, mutual coordination and development of the environment, taking the elderly as the special group, this paper follows the principles of the sustainable development, conducts the comprehensive design planning of aged care landscape architecture and makes a deeper understanding and exploration through changing the form of architectural space, ecological landscape planting, new materials and technology, ecological energy utilization.

  2. The extent of burning in African savanna

    NASA Technical Reports Server (NTRS)

    Cahoon, D. R. JR.; Levine, J. S.; Cofer, W. R. Iii; Stocks, B. J.

    1994-01-01

    The temporal and spatial distribution of African savanna grassland fires has been examined, and the areal extent of these fires has been estimated for the subequatorial African continent. African savanna fires have been investigated using remote sensing techniques and imagery collected by low-light sensors on Defense Meteorological Satellite Program (DMSP) satellites and by the Advanced Very High Resolution Radiometer (AVHRR) which is aboard polar orbiting National Oceanic and Atmospheric Administration (NOAA) satellites. DMSP imagery has been used to map the evolution of savanna burning over all of the African continent and the analysis of AVHRR imagery has been used to estimate the areal extent of the burning in the southern hemispheric African savannas. The work presented primarily reflects the analysiscompleted for the year 1987. However, comparisons have been made with other years and the representativeness of the 1987 analysis is discussed.

  3. Inferences of Present and Past Changes at Isolated Enclaves and Matrix of Savannas by Carbon Isotopes in a Transitional Forest-Savanna Area in Northern Amazonia

    NASA Astrophysics Data System (ADS)

    Couto-Santos, F. R.; Luizao, F. J.; Camargo, P. B.

    2013-12-01

    The evolutionary history of savannas influenced by short term climate cycles, during the Quaternary Period, could prompt variations in forest cover often related to movements of the forest-savanna boundary. In this study we investigated current and past changes in the structure of vegetation and the origins of savannas of different natures in a biogeographically and climatic transitional forest-savanna area in northern Amazonia. Variations in the isotopic composition of soil organic matter (δ13C) from surface soils (0-10 cm) along forest-savanna boundaries, detected by a sigmoidal non-linear function, were used to identify current changes in vegetation, while past changes were inferred by discontinuities in the evolution of δ13C with soil depth using piecewise regression associated with radiocarbon dating (14C). By comparing small isolated savanna enclaves inside a strictly protected nature reserve (ESEC Maracá) with its outskirts unprotected continuous savanna matrix, we found that origins and the patterns of dynamics were distinct between these areas and did not respond in the same way to climate change and fire events, either in the last decades or during the Holocene. The stability of the present boundaries of the surrounding savanna matrix reflects the resilience of the transitional forests under a recent intensified fire regime and favorable climate, while the deep forest soil isotopic signal indicated a forest shrinkage of at least 70 m occurring since its origin in early Holocene until 780 years BP associated with a climate drier than the current one. Contrarily, the protected enclaves inside ESEC Maracá, remained stable since the middle Holocene, suggesting a non-anthropogenic origin related to soil edaphic conditions, but with recent dynamics of advancing forest by 8 m century-1 favored by current climate and lacking fire events. A detailed understanding of the origins of savannas of distinct natures and the way they are affected by climate and fire

  4. Disaggregating tree and grass phenology in tropical savannas

    NASA Astrophysics Data System (ADS)

    Zhou, Qiang

    Savannas are mixed tree-grass systems and as one of the world's largest biomes represent an important component of the Earth system affecting water and energy balances, carbon sequestration and biodiversity as well as supporting large human populations. Savanna vegetation structure and its distribution, however, may change because of major anthropogenic disturbances from climate change, wildfire, agriculture, and livestock production. The overstory and understory may have different water use strategies, different nutrient requirements and have different responses to fire and climate variation. The accurate measurement of the spatial distribution and structure of the overstory and understory are essential for understanding the savanna ecosystem. This project developed a workflow for separating the dynamics of the overstory and understory fractional cover in savannas at the continental scale (Australia, South America, and Africa). Previous studies have successfully separated the phenology of Australian savanna vegetation into persistent and seasonal greenness using time series decomposition, and into fractions of photosynthetic vegetation (PV), non-photosynthetic vegetation (NPV) and bare soil (BS) using linear unmixing. This study combined these methods to separate the understory and overstory signal in both the green and senescent phenological stages using remotely sensed imagery from the MODIS (MODerate resolution Imaging Spectroradiometer) sensor. The methods and parameters were adjusted based on the vegetation variation. The workflow was first tested at the Australian site. Here the PV estimates for overstory and understory showed best performance, however NPV estimates exhibited spatial variation in validation relationships. At the South American site (Cerrado), an additional method based on frequency unmixing was developed to separate green vegetation components with similar phenology. When the decomposition and frequency methods were compared, the frequency

  5. Determinants of woody cover in African savannas

    USGS Publications Warehouse

    Sankaran, M.; Hanan, N.P.; Scholes, R.J.; Ratnam, J.; Augustine, D.J.; Cade, B.S.; Gignoux, J.; Higgins, S.I.; Le, Roux X.; Ludwig, F.; Ardo, J.; Banyikwa, F.; Bronn, A.; Bucini, G.; Caylor, K.K.; Coughenour, M.B.; Diouf, A.; Ekaya, W.; Feral, C.J.; February, E.C.; Frost, P.G.H.; Hiernaux, P.; Hrabar, H.; Metzger, K.L.; Prins, H.H.T.; Ringrose, S.; Sea, W.; Tews, J.; Worden, J.; Zambatis, N.

    2005-01-01

    Savannas are globally important ecosystems of great significance to human economies. In these biomes, which are characterized by the co-dominance of trees and grasses, woody cover is a chief determinant of ecosystem properties 1-3. The availability of resources (water, nutrients) and disturbance regimes (fire, herbivory) are thought to be important in regulating woody cover1,2,4,5, but perceptions differ on which of these are the primary drivers of savanna structure. Here we show, using data from 854 sites across Africa, that maximum woody cover in savannas receiving a mean annual precipitation (MAP) of less than ???650 mm is constrained by, and increases linearly with, MAP. These arid and semi-arid savannas may be considered 'stable' systems in which water constrains woody cover and permits grasses to coexist, while fire, herbivory and soil properties interact to reduce woody cover below the MAP-controlled upper bound. Above a MAP of ???650 mm, savannas are 'unstable' systems in which MAP is sufficient for woody canopy closure, and disturbances (fire, herbivory) are required for the coexistence of trees and grass. These results provide insights into the nature of African savannas and suggest that future changes in precipitation 6 may considerably affect their distribution and dynamics. ?? 2005 Nature Publishing Group.

  6. Determinants of woody cover in African savannas.

    PubMed

    Sankaran, Mahesh; Hanan, Niall P; Scholes, Robert J; Ratnam, Jayashree; Augustine, David J; Cade, Brian S; Gignoux, Jacques; Higgins, Steven I; Le Roux, Xavier; Ludwig, Fulco; Ardo, Jonas; Banyikwa, Feetham; Bronn, Andries; Bucini, Gabriela; Caylor, Kelly K; Coughenour, Michael B; Diouf, Alioune; Ekaya, Wellington; Feral, Christie J; February, Edmund C; Frost, Peter G H; Hiernaux, Pierre; Hrabar, Halszka; Metzger, Kristine L; Prins, Herbert H T; Ringrose, Susan; Sea, William; Tews, Jörg; Worden, Jeff; Zambatis, Nick

    2005-12-08

    Savannas are globally important ecosystems of great significance to human economies. In these biomes, which are characterized by the co-dominance of trees and grasses, woody cover is a chief determinant of ecosystem properties. The availability of resources (water, nutrients) and disturbance regimes (fire, herbivory) are thought to be important in regulating woody cover, but perceptions differ on which of these are the primary drivers of savanna structure. Here we show, using data from 854 sites across Africa, that maximum woody cover in savannas receiving a mean annual precipitation (MAP) of less than approximately 650 mm is constrained by, and increases linearly with, MAP. These arid and semi-arid savannas may be considered 'stable' systems in which water constrains woody cover and permits grasses to coexist, while fire, herbivory and soil properties interact to reduce woody cover below the MAP-controlled upper bound. Above a MAP of approximately 650 mm, savannas are 'unstable' systems in which MAP is sufficient for woody canopy closure, and disturbances (fire, herbivory) are required for the coexistence of trees and grass. These results provide insights into the nature of African savannas and suggest that future changes in precipitation may considerably affect their distribution and dynamics.

  7. Large carnivores make savanna tree communities less thorny.

    PubMed

    Ford, Adam T; Goheen, Jacob R; Otieno, Tobias O; Bidner, Laura; Isbell, Lynne A; Palmer, Todd M; Ward, David; Woodroffe, Rosie; Pringle, Robert M

    2014-10-17

    Understanding how predation risk and plant defenses interactively shape plant distributions is a core challenge in ecology. By combining global positioning system telemetry of an abundant antelope (impala) and its main predators (leopards and wild dogs) with a series of manipulative field experiments, we showed that herbivores' risk-avoidance behavior and plants' antiherbivore defenses interact to determine tree distributions in an African savanna. Well-defended thorny Acacia trees (A. etbaica) were abundant in low-risk areas where impala aggregated but rare in high-risk areas that impala avoided. In contrast, poorly defended trees (A. brevispica) were more abundant in high- than in low-risk areas. Our results suggest that plants can persist in landscapes characterized by intense herbivory, either by defending themselves or by thriving in risky areas where carnivores hunt.

  8. A model inter-comparison study to examine limiting factors in modelling Australian tropical savannas

    NASA Astrophysics Data System (ADS)

    Whitley, R.; Beringer, J.; Hutley, L.; Abramowitz, G.; De Kauwe, M. G.; Duursma, R.; Evans, B.; Haverd, V.; Li, L.; Ryu, Y.; Smith, B.; Wang, Y.-P.; Williams, M.; Yu, Q.

    2015-12-01

    Savanna ecosystems are one of the most dominant and complex terrestrial biomes that derives from a distinct vegetative surface comprised of co-dominant tree and grass populations. While these two vegetation types co-exist functionally, demographically they are not static, but are dynamically changing in response to environmental forces such as annual fire events and rainfall variability. Modelling savanna environments with the current generation of terrestrial biosphere models (TBMs) has presented many problems, particularly describing fire frequency and intensity, phenology, leaf biochemistry of C3 and C4 photosynthesis vegetation, and root water uptake. In order to better understand why TBMs perform so poorly in savannas, we conducted a model inter-comparison of 6 TBMs and assessed their performance at simulating latent energy (LE) and gross primary productivity (GPP) for five savanna sites along a rainfall gradient in northern Australia. Performance in predicting LE and GPP was measured using an empirical benchmarking system, which ranks models by their ability to utilise meteorological driving information to predict the fluxes. On average, the TBMs performed as well as a multi-linear regression of the fluxes against solar radiation, temperature and vapour pressure deficit, but were outperformed by a more complicated nonlinear response model that also included the leaf area index (LAI). This identified that the TBMs are not fully utilising their input information effectively in determining savanna LE and GPP, and highlights that savanna dynamics cannot be calibrated into models and that there are problems in underlying model processes. We identified key weaknesses in a model's ability to simulate savanna fluxes and their seasonal variation, related to the representation of vegetation by the models and root water uptake. We underline these weaknesses in terms of three critical areas for development. First, prescribed tree-rooting depths must be deep enough

  9. A model inter-comparison study to examine limiting factors in modelling Australian tropical savannas

    NASA Astrophysics Data System (ADS)

    Whitley, Rhys; Beringer, Jason; Hutley, Lindsay B.; Abramowitz, Gab; De Kauwe, Martin G.; Duursma, Remko; Evans, Bradley; Haverd, Vanessa; Li, Longhui; Ryu, Youngryel; Smith, Benjamin; Wang, Ying-Ping; Williams, Mathew; Yu, Qiang

    2016-06-01

    The savanna ecosystem is one of the most dominant and complex terrestrial biomes, deriving from a distinct vegetative surface comprised of co-dominant tree and grass populations. While these two vegetation types co-exist functionally, demographically they are not static but are dynamically changing in response to environmental forces such as annual fire events and rainfall variability. Modelling savanna environments with the current generation of terrestrial biosphere models (TBMs) has presented many problems, particularly describing fire frequency and intensity, phenology, leaf biochemistry of C3 and C4 photosynthesis vegetation, and root-water uptake. In order to better understand why TBMs perform so poorly in savannas, we conducted a model inter-comparison of six TBMs and assessed their performance at simulating latent energy (LE) and gross primary productivity (GPP) for five savanna sites along a rainfall gradient in northern Australia. Performance in predicting LE and GPP was measured using an empirical benchmarking system, which ranks models by their ability to utilise meteorological driving information to predict the fluxes. On average, the TBMs performed as well as a multi-linear regression of the fluxes against solar radiation, temperature and vapour pressure deficit but were outperformed by a more complicated nonlinear response model that also included the leaf area index (LAI). This identified that the TBMs are not fully utilising their input information effectively in determining savanna LE and GPP and highlights that savanna dynamics cannot be calibrated into models and that there are problems in underlying model processes. We identified key weaknesses in a model's ability to simulate savanna fluxes and their seasonal variation, related to the representation of vegetation by the models and root-water uptake. We underline these weaknesses in terms of three critical areas for development. First, prescribed tree-rooting depths must be deep enough

  10. 36 CFR 219.12 - Collaboration and cooperatively developed landscape goals.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Collaborative Planning for Sustainability § 219.12 Collaboration and cooperatively developed landscape goals. (a) Collaboration. To promote sustainability, the responsible official must actively engage the American public... and foster understanding of the nation's declaration of environmental policy as set forth in...

  11. 36 CFR 219.12 - Collaboration and cooperatively developed landscape goals.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Collaborative Planning for Sustainability § 219.12 Collaboration and cooperatively developed landscape goals. (a) Collaboration. To promote sustainability, the responsible official must actively engage the American public... and foster understanding of the nation's declaration of environmental policy as set forth in...

  12. Developing a predictive understanding of landscape importance to the Punan-Pelancau of East Kalimantan, Borneo.

    PubMed

    Cunliffe, Robert N; Lynam, Timothy J P; Sheil, Douglas; Wan, Meilinda; Salim, Agus; Basuki, Imam; Priyadi, Hari

    2007-11-01

    In order for local community views to be incorporated into new development initiatives, their perceptions need to be clearly understood and documented in a format that is readily accessible to planners and developers. The current study sought to develop a predictive understanding of how the Punan Pelancau community, living in a forested landscape in East Kalimantan, assigns importance to its surrounding landscapes and to present these perceptions in the form of maps. The approach entailed the iterative use of a combination of participatory community evaluation methods and more formal modeling and geographic information system techniques. Results suggest that landscape importance is largely dictated by potential benefits, such as inputs to production, health, and houses. Neither land types nor distance were good predictors of landscape importance. The grid-cell method, developed as part of the study, appears to offer a simple technique to capture and present the knowledge of local communities, even where their relationship to the land is highly complex, as was the case for this particular community.

  13. Development of methods for the restoration of the American elm in forested landscapes

    Treesearch

    James M. Slavicek

    2013-01-01

    A project was initiated in 2003 to establish test sites to develop methods to reintroduce the American elm (Ulmus americana L.) in forested landscapes. American elm tree strains with high levels of tolerance to Dutch elm disease (DED) were established in areas where the trees can naturally regenerate and spread. The process of regeneration will...

  14. Initial landscape changes associated with Marcellus shale development—implications for forests and wildlife

    Treesearch

    Margaret Brittingham; Patrick Drohan; Joseph. Bishop

    2013-01-01

    Marcellus shale development is occurring rapidly across Pennsylvania. We conducted a geographic information system (GIS) analysis using available Pennsylvania Department of Environmental Protection permit data, before and after photos, ground-truthing, and fi eld measurements to describe landscape change within the fi rst 3 years of active Marcellus exploration and...

  15. The challenges associated with developing science-based landscape scale management plans.

    Treesearch

    Robert C. Szaro; Douglas A. Jr. Boyce; Thomas. Puchlerz

    2005-01-01

    Planning activities over large landscapes poses a complex of challenges when trying to balance the implementation of a conservation strategy while still allowing for a variety of consumptive and nonconsumptive uses. We examine a case in southeast Alaska to illustrate the breadth of these challenges and an approach to developing a science-based resource plan. Not only...

  16. Birds in a Developing Area: The Need for Habitat Protection at the Landscape Scale

    Treesearch

    Jane A. Fitzgerald; Jonathan Bart; Harold D. Brown; Kathy Lee

    2005-01-01

    We used fixed-distance point counts to monitor bird populations from 1994-1998 in a rapidly urbanizing region of southwestern Missouri. Prior to the early 1990s, the rural landscape was a mosaic of forest, dolomite glades, and pasture but development proceeded rapidly in the 1990s with increased promotion of Branson, Missouri as a vacation and retirement destination....

  17. Understanding landscape change in open space neighborhoods: views from developers and residents

    Treesearch

    Christine A. Vogt; Robert W. Marans

    2003-01-01

    The landscape is changing across the country, particularly in outlying areas of US cities. These fringe areas, often called exurbia, continue to move further from the city core. Their growth is largely created by new residential, commercial, and industrial development. Dramatic land use and land cover changes in these areas from agricultural or forested to buildings...

  18. Understanding Landscape Change in Open Space Neighborhoods: Views from Developers and Residents

    Treesearch

    Christine A. Vogt; Robert W. Marans

    2002-01-01

    The landscape is changing across the country, particularly in outlying areas of US cities. These fringe areas, often called exurbia, continue to move further from the city core. Their growth is largely created by new residential, commercial ,and industrial development. Dramatic land use and land cover changes in these areas from agricultural or forested to buildings...

  19. Landscape pattern analysis for assessing ecosystem condition: Development of a multi-resolution method and application to watershed-delineated landscapes in Pennsylvania

    NASA Astrophysics Data System (ADS)

    Johnson, Glen D.

    Protection of ecological resources requires the study and management of whole landscape-level ecosystems. The subsequent need for characterizing landscape structure has led to a variety of measurements for assessing different aspects of spatial patterns; however, most of these measurements are known to depend on both the spatial extent of a specified landscape and the measurement grain; therefore, multi-scale measurements would be more informative. In response, a new method is developed for obtaining a multi-resolution characterization of fragmentation patterns in land cover raster maps within a fixed geographic extent. The concept of conditional entropy is applied to quantify landscape fragmentation as one moves from larger "parent" land cover pixels to smaller "child" pixels that are hierarchically nested within the parent pixels. When applied over a range of resolutions, one obtains a "conditional entropy profile" that can be defined by three parameters. A method for stochastically simulating landscapes is also developed which allows evaluation of the expected behavior of conditional entropy profiles under known landscape generating mechanisms. This modeling approach also allows for determining sample distributions of different landscape measurements via Monte Carlo simulations. Using an eight-category raster map that was based on 30-meter resolution LANDSAT TM images, a suite of landscape measurements was obtained for each of 102 Pennsylvania watersheds (a complete tessellation of the state). This included conditional entropy profiles based on the random filter for degrading raster map resolutions. For these watersheds, the conditional entropy profiles are quite sensitive to changing pattern, and together with the readily-available marginal land cover proportions, appear to be very valuable for categorizing landscapes with respect to common types. These profiles have the further appeal of presenting multi-scale fragmentation patterns in a way that can be easily

  20. Untangling human development and natural gradients: implications of underlying correlation structure for linking landscapes and riverine ecosystems

    Treesearch

    Yasmin Lucero; E. Ashley Steel; Kelly M. Burnett; Kelly. Christiansen

    2011-01-01

    Increasingly, ecologists seek to identify and quantify relationships between landscape gradients and aquatic ecosystems. Considerable statistical challenges emerge in this effort, some of which are attributable to multicollinearity between human development and landscape gradients. In this paper, we measure the covariation between human development—such as agriculture...

  1. From Understanding the Development Landscape of the Canonical Fate-Switch Pair to Constructing a Dynamic Landscape for Two-Step Neural Differentiation

    PubMed Central

    2012-01-01

    Abstract Recent progress in stem cell biology, notably cell fate conversion, calls for novel theoretical understanding for cell differentiation. The existing qualitative concept of Waddington’s “epigenetic landscape” has attracted particular attention because it captures subsequent fate decision points, thus manifesting the hierarchical (“tree-like”) nature of cell fate diversification. Here, we generalized a recent work and explored such a developmental landscape for a two-gene fate decision circuit by integrating the underlying probability landscapes with different parameters (corresponding to distinct developmental stages). The change of entropy production rate along the parameter changes indicates which parameter changes can represent a normal developmental process while other parameters’ change can not. The transdifferentiation paths over the landscape under certain conditions reveal the possibility of a direct and reversible phenotypic conversion. As the intensity of noise increases, we found that the landscape becomes flatter and the dominant paths more straight, implying the importance of biological noise processing mechanism in development and reprogramming. We further extended the landscape of the one-step fate decision to that for two-step decisions in central nervous system (CNS) differentiation. A minimal network and dynamic model for CNS differentiation was firstly constructed where two three-gene motifs are coupled. We then implemented the SDEs (Stochastic Differentiation Equations) simulation for the validity of the network and model. By integrating the two landscapes for the two switch gene pairs, we constructed the two-step development landscape for CNS differentiation. Our work provides new insights into cellular differentiation and important clues for better reprogramming strategies. PMID:23300518

  2. A LANDSCAPE DEVELOPMENT INTENSITY MAP OF MARYLAND, USA

    EPA Science Inventory

    We present a map of human development intensity for central and eastern Maryland using an index derived from energy systems principles. Brown and Vivas developed a measure of the intensity of human development based on the nonrenewable energy use per unit area as an index to exp...

  3. A LANDSCAPE DEVELOPMENT INTENSITY MAP OF MARYLAND, USA

    EPA Science Inventory

    We present a map of human development intensity for central and eastern Maryland using an index derived from energy systems principles. Brown and Vivas developed a measure of the intensity of human development based on the nonrenewable energy use per unit area as an index to exp...

  4. Electricity, policy and landscape: An integrated geographic approach to renewable electric energy development

    NASA Astrophysics Data System (ADS)

    Serralles, Roberto Juan

    The development of a centralized electric energy infrastructure in industrialized areas of the world has significantly impacted the character and nature of local and regional landscapes. Since their development at the beginning of the 20th century, electric energy networks have become one of the most distinctive and visible landscape features found in industrialized regions today. At the same time, our perceptual relationship with the electric energy infrastructure, along with the meanings we ascribe to these electricity-related landscape features, has shifted dramatically over the last century. The early stages of the historical development of the electric energy infrastructure in the United States and Europe were marked by an optimistic popular perception that celebrated electricity's vast potential as an economic and social transformative agent. However, by the end of the 20th century, concerns in these industrialized regions over environmental degradation and resource scarcity significantly altered these popularized political and aesthetic judgments. Ironically, the recent growth of renewable energy projects, in particular large-scale wind energy facilities, while seeking to ameliorate the industrial causes of environmental degradation, has sparked an intense public debate over the visual impacts of these projects on local landscapes. To understand this shifting perceptual relationship between industrialized societies and the electricity landscapes found in these regions, in this dissertation I analyze the evolving social, economic and political milieu underlying the creation and reproduction of meanings ascribed to the visual landscape modifications spawned by the electricity network. In addition, I describe the political conditions and trends that are shaping and contextualizing the role of renewable electric energy facilities in the future electricity budgets of the United States and the EU. To address the concerns over negative visual impacts of renewable

  5. Deriving Multiple Benefits from Carbon Market-Based Savanna Fire Management: An Australian Example.

    PubMed

    Russell-Smith, Jeremy; Yates, Cameron P; Edwards, Andrew C; Whitehead, Peter J; Murphy, Brett P; Lawes, Michael J

    2015-01-01

    Carbon markets afford potentially useful opportunities for supporting socially and environmentally sustainable land management programs but, to date, have been little applied in globally significant fire-prone savanna settings. While fire is intrinsic to regulating the composition, structure and dynamics of savanna systems, in north Australian savannas frequent and extensive late dry season wildfires incur significant environmental, production and social impacts. Here we assess the potential of market-based savanna burning greenhouse gas emissions abatement and allied carbon biosequestration projects to deliver compatible environmental and broader socio-economic benefits in a highly biodiverse north Australian setting. Drawing on extensive regional ecological knowledge of fire regime effects on fire-vulnerable taxa and communities, we compare three fire regime metrics (seasonal fire frequency, proportion of long-unburnt vegetation, fire patch-size distribution) over a 15-year period for three national parks with an indigenously (Aboriginal) owned and managed market-based emissions abatement enterprise. Our assessment indicates improved fire management outcomes under the emissions abatement program, and mostly little change or declining outcomes on the parks. We attribute improved outcomes and putative biodiversity benefits under the abatement program to enhanced strategic management made possible by the market-based mitigation arrangement. For these same sites we estimate quanta of carbon credits that could be delivered under realistic enhanced fire management practice, using currently available and developing accredited Australian savanna burning accounting methods. We conclude that, in appropriate situations, market-based savanna burning activities can provide transformative climate change mitigation, ecosystem health, and community benefits in northern Australia, and, despite significant challenges, potentially in other fire-prone savanna settings.

  6. Deriving Multiple Benefits from Carbon Market-Based Savanna Fire Management: An Australian Example

    PubMed Central

    Russell-Smith, Jeremy; Yates, Cameron P.; Edwards, Andrew C.; Whitehead, Peter J.; Murphy, Brett P.; Lawes, Michael J.

    2015-01-01

    Carbon markets afford potentially useful opportunities for supporting socially and environmentally sustainable land management programs but, to date, have been little applied in globally significant fire-prone savanna settings. While fire is intrinsic to regulating the composition, structure and dynamics of savanna systems, in north Australian savannas frequent and extensive late dry season wildfires incur significant environmental, production and social impacts. Here we assess the potential of market-based savanna burning greenhouse gas emissions abatement and allied carbon biosequestration projects to deliver compatible environmental and broader socio-economic benefits in a highly biodiverse north Australian setting. Drawing on extensive regional ecological knowledge of fire regime effects on fire-vulnerable taxa and communities, we compare three fire regime metrics (seasonal fire frequency, proportion of long-unburnt vegetation, fire patch-size distribution) over a 15-year period for three national parks with an indigenously (Aboriginal) owned and managed market-based emissions abatement enterprise. Our assessment indicates improved fire management outcomes under the emissions abatement program, and mostly little change or declining outcomes on the parks. We attribute improved outcomes and putative biodiversity benefits under the abatement program to enhanced strategic management made possible by the market-based mitigation arrangement. For these same sites we estimate quanta of carbon credits that could be delivered under realistic enhanced fire management practice, using currently available and developing accredited Australian savanna burning accounting methods. We conclude that, in appropriate situations, market-based savanna burning activities can provide transformative climate change mitigation, ecosystem health, and community benefits in northern Australia, and, despite significant challenges, potentially in other fire-prone savanna settings. PMID:26630453

  7. The epigenetic landscape of mammary gland development and functional differentiation

    USDA-ARS?s Scientific Manuscript database

    Most of the development and functional differentiation in the mammary gland occur after birth. Epigenetics is defined as the stable alterations in gene expression potential that arise during development and proliferation. Epigenetic changes are mediated at the biochemical level by the chromatin conf...

  8. Fire and home range expansion: a behavioral response to burning among savanna dwelling vervet monkeys (Chlorocebus aethiops).

    PubMed

    Herzog, Nicole M; Parker, Christopher H; Keefe, Earl R; Coxworth, James; Barrett, Alan; Hawkes, Kristen

    2014-08-01

    The behavioral adaptations of primates to fire-modified landscapes are of considerable interest to anthropologists because fire is fundamental to life in the African savanna-the setting in which genus Homo evolved. Here we report the behavioral responses of a savanna-dwelling primate, vervet monkeys (Chlorocebus aethiops), to fire-induced ecological change. Using behavioral and spatial data to characterize ranging patterns prior to and postburn and between burn and nonburn years, we show that these primates inhabiting small, spatially bound, riverine habitats take advantage of newly burned savanna landscapes. When subjects encountered controlled fires, they did not flee but instead avoided the path of the fire seemingly unbothered by its approach. After fire, the primates' home range expanded into newly burned but previously unused areas. These results contribute to understanding the response of non-human primates to fire-modified landscapes and can shed light on the nature and scope of opportunities and constraints posed by the emergence of fire-affected landscapes in the past. Results also expose deficiencies in our knowledge of fire-related behavioral responses in the primate lineage and highlight the need for further investigation of these responses as they relate to foraging opportunities, migration, resource use, and especially fire-centric adaptations in our own genus.

  9. Estimating Vegetation Structure in African Savannas using High Spatial Resolution Imagery

    NASA Astrophysics Data System (ADS)

    Axelsson, C.; Hanan, N. P.

    2016-12-01

    High spatial resolution satellite imagery allows for detailed mapping of trees in savanna landscapes, including estimates of woody cover, tree densities, crown sizes, and the spatial pattern of trees. By linking these vegetation parameters to rainfall and soil properties we gain knowledge of how the local environment influences vegetation. A thorough understanding of the underlying ecosystem processes is key to assessing the future productivity and stability of these ecosystems. In this study, we have processed and analyzed hundreds of sites sampled from African savannas across a wide range of rainfall and soil conditions. The vegetation at each site is classified using unsupervised classification with manual assignment into woody, herbaceous and bare cover classes. A crown delineation method further divides the woody areas into individual tree crowns. The results show that rainfall, soil, and topography interactively influence vegetation structure. We see that both total rainfall and rainfall seasonality play important roles and that soil type influences woody cover and the sizes of tree crowns.

  10. Seasonal Distribution of African Savanna Fires

    NASA Technical Reports Server (NTRS)

    Cahoon, Donald R.; Stocks, Brian J.; Levine, Joel S.; Cofer, Wesley R., III; O'Neill, Katherine P.

    1992-01-01

    Savannas consist of a continuous layer of grass interspersed with scattered trees or shrubs, and cover approx. 10 million square kilometers of tropical Africa. African savanna fires, almost all resulting from human activities, may produce as much as a third of the total global emissions from biomass burning. Little is known, however, about the frequency and location of these fires, and the area burned each year. Emissions from African savanna burning are known to be transported over the mid-Atlantic, south Pacific and Indian oceans; but to study fully the transport of regional savanna burning and the seasonality of the atmospheric circulation must be considered simultaneously. Here we describe the temporal and spatial distribution of savanna fires over the entire African continent, as determined from night-time satellite imagery. We find that, contrary to expectations, most fires are left to burn uncontrolled, so that there is no strong diurnal cycle in the fire frequency. The knowledge gained from this study regarding the distribution and variability of fires will aid monitoring of the climatically important trace gases emitted from burning biomass.

  11. Agroforestry for landscape restoration and livelihood development in Central Asia.

    Treesearch

    U. Djanibekov; Klara Dzhakypbekova; James Chamberlain; Horst Weyerhaeuser; Robert Zomer; G. Villamor; J. Xu

    2016-01-01

    This paper discusses how the adoption of agroforestry for ecosystem and livelihood improvement in Central Asian countries can be enhanced. First, it describes how previous and current developments lead to changing environmental conditions, and how these changing conditions consequently affected the welfare of people. Environmental issues on a global level, such as...

  12. Soil development on stable landforms and implications for landscape studies

    USGS Publications Warehouse

    Harden, J.W.

    1990-01-01

    Soil development parameters include a wide variety of morphological, chemical, and mineralogical parameters, but some of the best indicators of time and surface stability are derived from field morphology. Over long time-spans, the most common time function for soil development is exponential or logarithmic, in which rates decrease with increasing age. Over shorter time-spans in semi-arid and moister climates, Holocene and Pleistocene soil development functions appear as linear segments, with Holocene rates about 10 to 50 times those of Pleistocene rates. In contrast to significant temporal variation in rates, geographical variation in rates within (a) the southern Great Basin and (b) the east Central Valley of California is on the order of 2 or 3 times. When comparing soil development indices of the semi-arid Great Basin to those of moister central California, Holocene rates are similar, but Pleistocene rates are more than 10 times slower in the Great Basin. In a range of climatic settings, the reasons for declining rates over time are several and are complexly related to erosional history, fluxes in water and dust related to climatic changes, rates of primary mineral dissolution, and intrinsic soil processes. ?? 1990.

  13. Landscape development and mule deer habitat in Central Oregon

    Treesearch

    James A. Duncan; Theresa Burcsu

    2012-01-01

    This research explored the ecological consequences of rural residential development and different management regimes on a tract of former industrial timberland in central Oregon known as the Bull Springs. Forage quality and habitat suitability models for mule deer (Odocoileus hemionus) winter range were joined to the outputs of a spatially explicit...

  14. Design, development, and application of LANDIS-II, a spatial landscape simulation model with flexible temporal and spatial resolution

    Treesearch

    Robert M. Scheller; James B. Domingo; Brian R. Sturtevant; Jeremy S. Williams; Arnold Rudy; Eric J. Gustafson; David J. Mladenoff

    2007-01-01

    We introduce LANDIS-II, a landscape model designed to simulate forest succession and disturbances. LANDIS-II builds upon and preserves the functionality of previous LANDIS forest landscape simulation models. LANDIS-II is distinguished by the inclusion of variable time steps for different ecological processes; our use of a rigorous development and testing process used...

  15. Development of a Digital Aquifer Permeability Map for the Pacific Southwest in Support of Hydrologic Landscape Classification: Methods

    EPA Science Inventory

    Researchers at the U.S. Environmental Protection Agency’s Western Ecology Division have been developing hydrologic landscape maps for selected U.S. states in an effort to create a method to identify the intrinsic watershed attributes of landscapes in regions with little dat...

  16. Development of a Digital Aquifer Permeability Map for the Pacific Southwest in Support of Hydrologic Landscape Classification: Methods

    EPA Science Inventory

    Researchers at the U.S. Environmental Protection Agency’s Western Ecology Division have been developing hydrologic landscape maps for selected U.S. states in an effort to create a method to identify the intrinsic watershed attributes of landscapes in regions with little dat...

  17. Effects of residential development and landscape composition on the breeding birds of Placer county's foothill oak woodlands

    Treesearch

    Diana Stralberg; Brian Williams

    2002-01-01

    This study examines the effect of rural residential development and landscape composition on breeding birds in Placer County’s foothill oak woodlands. Point count survey data were used to construct generalized linear models for individual species' abundance or probability of occurrence, based on two sets of variables: GIS-derived landscape characteristics,...

  18. Anticipating forest and range land development in central Oregon (USA) for landscape analysis, with an example application involving mule deer

    Treesearch

    Jeffrey D. Kline; Alissa Moses; Theresa Burcsu

    2010-01-01

    Forest policymakers, public lands managers, and scientists in the Pacific Northwest (USA) seek ways to evaluate the landscape-level effects of policies and management through the multidisciplinary development and application of spatially explicit methods and models. The Interagency Mapping and Analysis Project (IMAP) is an ongoing effort to generate landscape-wide...

  19. Development of a reproducible method for determining quantity of water and its configuration in a marsh landscape

    USGS Publications Warehouse

    Suir, Glenn M.; Evers, D. Elaine; Steyer, Gregory D.; Sasser, Charles E.

    2013-01-01

    Coastal Louisiana is a dynamic and ever-changing landscape. From 1956 to 2010, over 3,734 km2 of Louisiana's coastal wetlands have been lost due to a combination of natural and human-induced activities. The resulting landscape constitutes a mosaic of conditions from highly deteriorated to relatively stable with intact landmasses. Understanding how and why coastal landscapes change over time is critical to restoration and rehabilitation efforts. Historically, changes in marsh pattern (i.e., size and spatial distribution of marsh landmasses and water bodies) have been distinguished using visual identification by individual researchers. Difficulties associated with this approach include subjective interpretation, uncertain reproducibility, and laborious techniques. In order to minimize these limitations, this study aims to expand existing tools and techniques via a computer-based method, which uses geospatial technologies for determining shifts in landscape patterns. Our method is based on a raster framework and uses landscape statistics to develop conditions and thresholds for a marsh classification scheme. The classification scheme incorporates land and water classified imagery and a two-part classification system: (1) ratio of water to land, and (2) configuration and connectivity of water within wetland landscapes to evaluate changes in marsh patterns. This analysis system can also be used to trace trajectories in landscape patterns through space and time. Overall, our method provides a more automated means of quantifying landscape patterns and may serve as a reliable landscape evaluation tool for future investigations of wetland ecosystem processes in the northern Gulf of Mexico.

  20. LANDSCAPE STRUCTURE AND ESTUARINE CONDITION IN THE MID-ATLANTIC REGION OF THE UNITED STATES: I. DEVELOPING QUANTITATIVE RELATIONSHIPS

    EPA Science Inventory

    In a previously published study, quantitative relationships were developed between landscape metrics and sediment contamination for 25 small estuarine systems within Chesapeake Bay. Nonparametric statistical analysis (rank transformation) was used to develop an empirical relation...

  1. Ecosystem management can mitigate vegetation shifts induced by climate change in African savannas

    NASA Astrophysics Data System (ADS)

    Scheiter, Simon; Savadogo, Patrice

    2017-04-01

    The welfare of people in the tropics and sub-tropics strongly depends on goods and services that ecosystems supply. Flows of these ecosystem services are strongly influenced by interactions between climate change and land use. A prominent example are savannas, covering approximately 20% of the Earth's land surface. Key ecosystem services in these areas are fuel wood for cooking and heating, food production and livestock. Changes in the structure and dynamics of savanna vegetation may strongly influence local people's living conditions, as well as the climate system and biogeochemical cycles. We used a dynamic vegetation model to explore interactive effects of climate and land use on the vegetation structure, distribution and carbon cycling of African savannas under current and future conditions. More specifically, we simulate long term impacts of fire management, grazing and fuel wood harvesting. The model projects that under future climate without human land use impacts, large savanna areas would shift towards more wood dominated vegetation due to CO2 fertilization effects and changes in water use efficiency. However, land use activities can mitigate climate change impacts on vegetation to maintain desired ecosystem states that ensure fluxes of important ecosystem services. We then use optimization algorithms to identify sustainable land use strategies that maximize the utility of people managing savannas while preserving a stable vegetation state. Our results highlight that the development of land use policy for tropical and sub-tropical areas needs to account for climate change impacts on vegetation.

  2. Oak savanna restoration in central Iowa: Assessing indicators of forest health for ecological monitoring (PROJECT NC-F-04-02)

    Treesearch

    Heidi Asbjornsen; Lars Brudvig

    2013-01-01

    Savanna ecosystems were once a dominant feature of the Midwestern Corn Belt Plains ecoregion, occurring within the dynamic boundary between prairies to the west and forests to the east, and maintained in the landscape by complex interactions between fire, climate, topography, and human activities (Anderson 1998). Characterized by their continuous understory layer and...

  3. The Holocene landscape development of the Gareja region in eastern Georgia (Caucasus region) - an interdisciplinary approach

    NASA Astrophysics Data System (ADS)

    Elashvili, M.; Sukhishvili, L.; Navrozashvili, L.; Kikvadze, B.; Janelidze, Z.; von Suchodoletz, H.

    2014-12-01

    Recognizing the fact that we are living in a constantly changing world became actual during the last decades, and promoted numerous studies related to the environmental consequences of climate change and human impact. In this context, the study of human- and naturally-triggered palaeoenvironmental changes leads to a better understanding of possible changes during the future. Human impact became progressively important during the last millenia, and caused dramatic changes of the natural environment especially in fragile landscapes. The semi-arid Gareja region in the Iori Highland in the eastern part of the Republic of Georgia is characterized by an annual precipitation < 600 mm and shows an open steppic landscape today. As is known from historical sources, the landscape showed the same character already during the 6th century AD when the Gareja monastery located in the center of the region was founded by Assyrian monks. However, archaeological research carried out during the Soviet Period showed the existence of numerous settlements of bronze and iron age in this region almost devoid of water resources today, hinting to some sources of fresh water allowing people to live there during those periods. Furthermore, former archaeo-botanical studies assume that the region was covered by forests instead of steppes during the past, although there is no final proof yet. The goal of this study is to shed light on the development of the Gareja landscape during the prehistoric period and thus to address some of the issues described above. To do so, our work is based on the spatial pattern of prehistoric settlements derived from archaeologic data of the Soviet period, GIS stream modelling and the analysis of fluvial and slope deposits from the area using a multi-proxy approach. Altogether, these data indicate a dramatic palaeoenvironmental change in the Gareja region ca. 3 ka ago, leading to the recent steppe and almost unpopulated character of the landscape.

  4. Cumulative effects of developed road network on woodland--a landscape approach.

    PubMed

    Hosseini Vardei, Mahla; Salmanmahiny, Abdolrasoul; Monavari, Seyed Masoud; Kheirkhah Zarkesh, Mir Masoud

    2014-11-01

    Population growth, during the twentieth century, has increased demand for new farmlands. Accordingly, road networks have rapidly been developed to facilitate and accelerate human access to the essential resources resulted in extensive land use changes. The present study aims at assessing cumulative effects of developed road network on tree cover of Golestan Province in northern Iran. In order to detect changes over the study period of 1987-2002, the LULC map of the study area was initially prepared from the satellite images of Landsat TM (1987) and ETM+ (2002) using maximum likelihood supervised classification method. Afterwards, a total number of seven landscape matrices were selected to detect cumulative effects of the developed road network on woodland cover. The obtained results indicated that the fragile patches are mainly located at a distance of 171-342 m from the roadside. Furthermore, the majority of the patches affected by cumulative effects of development activities are situated at a distance of 342-684 m from the roadside, over an approximate area of 55 ha. The analysis of landscape metrics revealed that the developed road network has increased the landscape metrics of "the number of patches" and "patches perimeter-area ratio". It has also followed by a decrease in metrics such as "patches area", "Euclidean nearest neighbor distance", "patches proximity", "shape index", "contiguity", and "mean patches fractal dimension". The road network has also increased the "number of patches" and decreased the "mean patches area" representing further fragmentation of the landscape. With identification of highly affected wooldland cover patches, it would be possible to apply adaptive environmental management strategies to preserve and rehabilitate high-priority patches.

  5. Nonclinical development of a biosimilar: the current landscape.

    PubMed

    O'Connor, Anita; Rogge, Mark

    2013-03-01

    Preclinical studies have always been a critical component in the development program of a biopharmaceutical. With the advent of biosimilars the traditional preclinical program has changed to a new paradigm that integrates the concept of comparability with existing knowledge of the biopharmaceutical reference drug. Recently, the recommended preclinical program espoused by the European Medicines Agency has been modified to an abbreviated one that now emphasizes in vitro studies in lieu of in vivo for monoclonal antibody biosimilars. Likewise, the US FDA guidance on biosimilars suggests a flexible approach rather than the 28-day comparative toxicology studies that have historically been conducted for worldwide marketing. For now, structure and function studies will continue to be the foundation of the overall analytical assessment of biosimilarity. Traditional, comparative animal safety assessments will have limited value in determination of biosimilarity and in an abbreviated design they may have most value in providing assurance of safety in first-in-human trials when structural attributes are not indistinguishable. Unless this value can be proven, particularly as analytical technology improves in sensitivity, accuracy and precision, the need for these animal safety studies will diminish. Thus, the future lies in the ever evolving and sophisticated analytical studies that will replace the current in vivo studies for biosimilar products.

  6. Upper Middle Pleistocene climate and landscape development of Northern Germany

    NASA Astrophysics Data System (ADS)

    Urban, B.

    2009-04-01

    and the margin of a 286 m deep channel, subglacially eroded during the Elsterian, have recently been investigated by 9 counter flash or cored drillings (Stephan et al., in press). Studies focussed on the uppermost 50 m, made up of a series of approximately 9 m thick fluviatile sediments ("Leck-Folge") with intercalations of organic sand layers and a gyttja band, up to 1.5 m thick. This sequence is overlain by several metres of mainly decalcified groundmoraine, that, itself, is overlain by glaciofluvial and periglacial sediments. The palynological investigations of the gyttja reveal a floral development of interglacial character ("Leck-Thermomer"). Compared to other Middle Pleistocene warm periods in North Germany, correlations of the Leck-Thermomer with the Holsteinian and with the warm periods of the Reinsdorf and Wacken (Dömnitz) interglacials are precluded or appear rather implausible. The Leck-Thermomer is most likely a correlative of the marine oxigen isotope stage 7 c (MIS 7). Stephan, H.-J., Urban, B., Lüttig, G., Menke, B. und M. Sierralta: Palynologische, petrographische und geochronologische Untersuchungen der Leck-Warmzeit (spätes Mittelpleistozän) und ihrer begleitenden Sedimente.- [Palynological, petrographical, and geochronological investigations of deposits of the "Leck-Thermomer" and accompanying sediments].- Geologisches Jahrbuch, in press. Thieme, H., 1997. Lower Paleolithic hunting spears from Germany. Nature 385, 807-810. Urban, B. 1995. Palynological evidence of younger Middle Pleistocene Interglacials (Holsteinian, Reinsdorf, Schöningen) in the Schöningen open cast lignite mine (eastern Lower Saxony/Germany). Mededelingen Rijks Geologische Dienst 52, 175-186. Urban, B. 2006. Interglacial pollen records from Schöningen, north Germany.- In: THE CLIMATE OF PAST INTERGLACIALS. Sirocko, F., Litt, T., Claussen, M., Sanchez-Goni, M.F. (eds.), Springer Verlag; in press.

  7. A landscape ecology approach to assessing development impacts in the tropics: A geothermal energy example in Hawaii

    USGS Publications Warehouse

    Griffith, J.A.; Trettin, C.C.; O'Neill, R. V.

    2002-01-01

    Geographic information systems (GIS) are increasingly being used in environmental impact assessments (EIA) because GIS is useful for analysing spatial impacts of various development scenarios. Spatially representing these impacts provides another tool for landscape ecology in environmental and geographical investigations by facilitating analysis of the effects of landscape patterns on ecological processes and examining change over time. Landscape ecological principles are applied in this study to a hypothetical geothermal development project on the Island of Hawaii. Some common landscape pattern metrics were used to analyse dispersed versus condensed development scenarios and their effect on landscape pattern. Indices of fragmentation and patch shape did not appreciably change with additional development. The amount of forest to open edge, however, greatly increased with the dispersed development scenario. In addition, landscape metrics showed that a human disturbance had a greater simplifying effect on patch shape and also increased fragmentation than a natural disturbance. The use of these landscape pattern metrics can advance the methodology of applying GIS to EIA.

  8. Development of two landscape-scale arctic observatories in northern Alaska

    NASA Astrophysics Data System (ADS)

    Jones, B. M.; Arp, C. D.; Whitman, M. S.; Grosse, G.

    2016-12-01

    Lake-rich arctic lowland landscapes are particularly sensitive to changes occurring in both summer and winter climate. In northern Alaska, lakes may account for more than 20% of the land surface cover and thus factor prominently in the arctic system. However, long-term, integrated observations from lake-rich arctic landscapes are relatively sparse. During the past decade, we have developed two new landscape-scale arctic observatories in northern Alaska - the Teshekpuk Lake Observatory (TLO) and the Fish Creek Watershed Observatory (FCWO) to help fill critical data gaps associated with these prominent components of the arctic system. The TLO focuses on the largest arctic lake in Alaska and the ice-rich permafrost terrain between it and the Beaufort Sea coast to the north. The FCWO focuses on a 4,500 sq. km. watershed where lakes occupy 19% of the surface cover. Combined, the TLO and FCWO capture the diverse mosaic of terrain units and aquatic habitats that occur on the Arctic Coastal Plain of northern Alaska including deep dune trough lakes, shallow thermokarst lakes, drained thermokarst lake basins, thermokarst pits, beaded streams, both sand and gravel bedded rivers, rapidly eroding coastlines, and deltaic habitats. The TLO and FCWO are also ideal locations for long-term observations as these landscapes are responding rapidly to climate change and are also subject to land use changes associated with petroleum development. Here we provide an overview of the research infrastructure available at the TLO and FCWO and present data and findings from sensor networks, field studies, remotely sensed image analysis, models, limnological surveys, and paleoecological analyses. Ongoing projects at both observatories include establishment of automated and near-real time data transmission stations, detailed field studies, analysis of remotely sensed datasets to quantify regional landscape changes, climatic and hydrologic modeling, and analysis of paleoecological archives that

  9. Steady state, erosional continuity, and the topography of landscapes developed in layered rocks

    NASA Astrophysics Data System (ADS)

    Perne, Matija; Covington, Matthew D.; Thaler, Evan A.; Myre, Joseph M.

    2017-01-01

    The concept of topographic steady state has substantially informed our understanding of the relationships between landscapes, tectonics, climate, and lithology. In topographic steady state, erosion rates are equal everywhere, and steepness adjusts to enable equal erosion rates in rocks of different strengths. This conceptual model makes an implicit assumption of vertical contacts between different rock types. Here we hypothesize that landscapes in layered rocks will be driven toward a state of erosional continuity, where retreat rates on either side of a contact are equal in a direction parallel to the contact rather than in the vertical direction. For vertical contacts, erosional continuity is the same as topographic steady state, whereas for horizontal contacts it is equivalent to equal rates of horizontal retreat on either side of a rock contact. Using analytical solutions and numerical simulations, we show that erosional continuity predicts the form of flux steady-state landscapes that develop in simulations with horizontally layered rocks. For stream power erosion, the nature of continuity steady state depends on the exponent, n, in the erosion model. For n = 1, the landscape cannot maintain continuity. For cases where n ≠ 1, continuity is maintained, and steepness is a function of erodibility that is predicted by the theory. The landscape in continuity steady state can be quite different from that predicted by topographic steady state. For n < 1 continuity predicts that channels incising subhorizontal layers will be steeper in the weaker rock layers. For subhorizontal layered rocks with different erodibilities, continuity also predicts larger slope contrasts than in topographic steady state. Therefore, the relationship between steepness and erodibility within a sequence of layered rocks is a function of contact dip. For the subhorizontal limit, the history of layers exposed at base level also influences the steepness-erodibility relationship. If uplift rate

  10. The influence of different environmental and climatic conditions on vegetated aeolian dune landscape development and response

    NASA Astrophysics Data System (ADS)

    Nield, Joanna M.; Baas, Andreas C. W.

    2008-11-01

    Aeolian dune field development in coastal and semi-arid environments is a function of complex ecogeomorphic interactions which are sensitive to fluctuations in climatic and environmental conditions. We explore the relationships between ecological and geomorphic processes in the development of these landscape patterns and speculate on their response to variations in vegetation vitality and sediment transport capacity, indicating possible consequences of climate and land use change, using the Discrete ECogeomorphic Aeolian Landscape (DECAL) cellular automaton algorithm. This algorithm models dune field behaviour that reflects long-term trends prevalent in palaeo-records, but also elucidates possible evolutionary progressions, relaxation period sequences and threshold sensitivities. The landscape response is sensitive both to the perturbation itself and the state of the system when the disturbance occurs. Response amplitude decreases in simulated systems with reduced mobility unless an external disturbance mimicking fire or land clearance is applied concurrently with a reduction in growth vigour triggering a threshold type response when sufficient vegetation is removed. The model demonstrates that the relative response characteristics of the multiple vegetation types and their mutual feedback with geomorphic processes impart a significant influence on landscape equilibrium or attractor states. Fast growing vegetation enables the formation of hairpin (long-walled) parabolic dune systems, which eventually become sediment starved and stabilise, whereas inhospitable conditions inhibiting vegetation growth contribute to the development of active transgressive transverse dune fields. This simple vegetated dune model illustrates the power and versatility of a cellular automaton approach for exploring thresholds, sensitivities and possible evolutionary trajectories associated with the interactions between ecology, geomorphology and climatic conditions in complex earth surface

  11. The impact of industrial oil development on a protected area landscape: A case study on human population growth and landscape level change in Murchison Falls Conservation Area, Uganda.

    NASA Astrophysics Data System (ADS)

    Dowhaniuk, Nicholas; Hartter, Joel; Congalton, Russell G.; Palace, Michael W.; Ryan, Sadie J.

    2016-04-01

    Protected areas in Sub-Saharan Africa are sanctuaries for rich biodiversity and are important economic engines for African nations, but they are becoming increasingly threatened by discoveries of mineral deposits within and nearby their boundaries. In 2006, viable oil reserves were discovered in Murchison Falls Conservation Area (MFCA) in northern Uganda. Exploratory and appraisal activities concluded in 2014, and production is expected to begin in 2016. The oil development is associated with a substantial increase in human population outside MFCA, with people seeking jobs, land, and economic opportunity. Concomitant with this change is increased truck traffic, a sprawling and denser road network, and infrastructure within the park, which could have large impacts on both the flora and fauna. We examined the broader protected area landscape and the potential feedbacks from resource development on the ecosystem and local livelihoods. Our analysis combines a land cover analysis using Object Based Image Analysis of Landsat data (2002 and 2014), migration patterns and population change (1959-2014), and qualitative interview data. Our results suggest that most of the larger-scale impacts on the landscape and people are occurring in the western and northern sections, both inside and outside of the park. Additionally, oil development is not the only factor in the region influencing population growth and landscape change. Post conflict regrowth in the north, sugarcane production in the south, and migration to this region from conflict-ridden neighboring countries are also playing a vital role in human migration shaping the MFCA Landscape. Understanding the social and environmental changes and impacts in the MFCA and its surrounding areas will add to limited literature on the impacts of resource extraction on local, subsistence communities and landscape level change, which will be important as access and pressure for oil and minerals within protected areas continues to rise.

  12. Prospects of the ICESat-2 laser altimetry mission for savanna ecosystem structural studies based on airborne simulation data

    NASA Astrophysics Data System (ADS)

    Gwenzi, David; Lefsky, Michael A.; Suchdeo, Vijay P.; Harding, David J.

    2016-08-01

    The next planned spaceborne lidar mission is the Ice, Cloud and land Elevation Satellite 2 (ICESat-2), which will use the Advanced Topographic Laser Altimeter System (ATLAS) sensor, a photon counting technique. To pre-validate the capability of this mission for studying three dimensional vegetation structure in savannas, we assessed the potential of the measurement approach to estimate canopy height in an oak savanna landscape. We used data from the Multiple Altimeter Beam Experimental Lidar (MABEL), an airborne photon counting lidar sensor developed by NASA's Goddard Space Flight Center. ATLAS-like data was generated using the MATLAS simulator, which adjusts MABEL data's detected number of signal and noise photons to that expected from the ATLAS instrument. Transects flown over the Tejon ranch conservancy in Kern County, California, USA were used for this work. For each transect we chose to use data from the near infrared channel that had the highest number of photons. We segmented each transect into 50 m, 25 m and 14 m long blocks and aggregated the photons in each block into a histogram based on their elevation values. We then used an automated algorithm to identify cut off points where the cumulative density of photons from the highest elevation indicates the presence of the canopy top and likewise where such cumulative density from the lowest elevation indicates the mean terrain elevation. MABEL derived height metrics were moderately correlated to discrete return lidar (DRL) derived height metrics (r2 and RMSE values ranging from 0.60 to 0.73 and 2.9 m to 4.4 m respectively) but MATLAS simulation resulted in more modest correlations with DRL indices (r2 ranging from 0.5 to 0.64 and RMSE from 3.6 m to 4.6 m). Simulations also indicated that the expected number of signal photons from ATLAS will be substantially lower, a situation that reduces canopy height estimation precision especially in areas of low density vegetation cover. On the basis of the simulated

  13. Prospects of the ICESat-2 Laser Altimetry Mission for Savanna Ecosystem Structural Studies Based on Airborne Simulation Data

    NASA Technical Reports Server (NTRS)

    Gwenzi, David; Lefsky, Michael A.; Suchdeo, Vijay P.; Harding, David J.

    2016-01-01

    The next planned spaceborne lidar mission is the Ice, Cloud and land Elevation Satellite 2 (ICESat-2), which will use the Advanced Topographic Laser Altimeter System (ATLAS) sensor, a photon counting technique. To pre-validate the capability of this mission for studying three dimensional vegetation structure in savannas, we assessed the potential of the measurement approach to estimate canopy height in an oak savanna landscape. We used data from the Multiple Altimeter Beam Experimental Lidar (MABEL), an airborne photon counting lidar sensor developed by NASA's Goddard Space Flight Center. ATLAS-like data was generated using the MATLAS simulator, which adjusts MABEL data's detected number of signal and noise photons to that expected from the ATLAS instrument. Transects flown over the Tejon ranch conservancy in Kern County, California, USA were used for this work. For each transect we chose to use data from the near infrared channel that had the highest number of photons. We segmented each transect into 50 m, 25 m and 14 m long blocks and aggregated the photons in each block into a histogram based on their elevation values. We then used an automated algorithm to identify cut off points where the cumulative density of photons from the highest elevation indicates the presence of the canopy top and likewise where such cumulative density from the lowest elevation indicates the mean terrain elevation. MABEL derived height metrics were moderately correlated to discrete return lidar (DRL) derived height metrics r(sub 2) and RMSE values ranging from 0.60 to 0.73 and 2.9 m to 4.4 m respectively) but MATLAS simulation resulted in more modest correlations with DRL indices r(sub 2) ranging from 0.5 to 0.64 and RMSE from 3.6 m to 4.6 m). Simulations also indicated that the expected number of signal photons from ATLAS will be substantially lower, a situation that reduces canopy height estimation precision especially in areas of low density vegetation cover. On the basis of the

  14. The Development of the Sacred Landscape of Saqqara in the Old Kingdom

    NASA Astrophysics Data System (ADS)

    Magli, Giulio

    2015-05-01

    Saqqara is one of the most important Necropolis in Egypt. In the course of the third millennium BC many Pharaohs choose Saqqara for their tombs. As a consequence the landscape constantly grew with the addition of new monuments, from the mastaba tombs of the first dynasty to the last pyramid of the Old Kingdom, that of Pepi II. The monuments were constructed respecting a series of topographical constraints which are not due to the morphology of the area but rather reflect symbolic - dynastic or astronomical - motivations. The analysis of these connections gives a better understanding of the choices made by the kings' architects in order to keep Maat - order - in the development of the site. Further, the way in which the sacred landscape came to be structured at the end of the Old Kingdom allows us to formulate a proposal for the possible location of the unique pyramid of the sixth dynasty which is still to be found: that of Userkare.

  15. Broad-scale assessments of ecological landscapes: developing methods and applications

    USGS Publications Warehouse

    Carr, Natasha B.; Wood, David J. A.; Bowen, Zachary H.; Haby, Travis S.

    2015-01-01

    A major component of the BLM Landscape Approach is the Rapid Ecoregional Assessment (REA) program. REAs identify important ecosystems and wildlife habitats at broad spatial scales and determine where these resources are at risk from environmental stressors that can affect the integrity of ecological systems. Building on the lessons learned from completed or current REAs, the BLM, in partnership with the U.S. Geological Survey, will perform systematic comparisons of REA methods to identify the most promising suite of landscape-level analysis tools. In addition, the BLM and USGS will develop practical applications that demonstrate how to incorporate assessment information to address existing management issues, such as cumulative effects of proposed management actions. The outcome of these efforts will be a set of comprehensive technical guidance documents for conducting and applying broad-scale assessments.

  16. The potential of computed crystal energy landscapes to aid solid-form development.

    PubMed

    Price, Sarah L; Reutzel-Edens, Susan M

    2016-06-01

    Solid-form screening to identify all solid forms of an active pharmaceutical ingredient (API) has become increasingly important in ensuring the quality by design of pharmaceutical products and their manufacturing processes. However, despite considerable enlargement of the range of techniques that have been shown capable of producing novel solid forms, it is possible that practically important forms might not be found in the short timescales currently allowed for solid-form screening. Here, we report on the state-of-the-art use of computed crystal energy landscapes to complement pharmaceutical solid-form screening. We illustrate how crystal energy landscapes can help establish molecular-level understanding of the crystallization behavior of APIs and enhance the ability of solid-form screening to facilitate pharmaceutical development.

  17. Origin and dynamics of the northern South American coastal savanna belt during the Holocene - the role of climate, sea-level, fire and humans

    NASA Astrophysics Data System (ADS)

    Alizadeh, Kamaleddin; Cohen, Marcelo; Behling, Hermann

    2015-08-01

    Presence of a coastal savanna belt expanding from British Guiana to northeastern Brazil cannot be explained by present-day climate. Using pollen and charcoal analyses on an 11.6 k old sediment core from a coastal depression in the savanna belt near the mouth of the Amazon River we investigated the paleoenvironmental history to shed light on this question. Results indicate that small areas of savanna accompanied by a forest type composed primarily by the genus Micropholis (Sapotaceae) that has no modern analog existed at the beginning of the Holocene. After 11,200 cal yr BP, savanna accompanied by few trees replaced the forest. In depressions swamp forest developed and by ca 10,000 cal yr BP replaced by Mauritia swamps. Between 8500 and 5600 cal yr BP gallery forest (composed mainly of Euphorbiaceae) and swamp forest succeeded the treeless savanna. The modern vegetation with alternating gallery forest and savanna developed after 5600 cal yr BP. We suggest that the early Holocene no-analog forest is a relict of previously more extensive forest under cooler and moister Lateglacial conditions. The early Holocene savanna expansion indicates a drier phase probably related to the shift of the Intertropical Convergence Zone (ITCZ) towards its northernmost position. The mid-Holocene forest expansion is probably a result of the combined influence of equatorwards shift of ITCZ joining the South Atlantic Convergence Zone (SACZ). The ecosystem variability during the last 5600 cal yr BP, formed perhaps under influence of intensified ENSO condition. High charcoal concentrations, especially during the early Holocene, indicate that natural and/or anthropogenic fires may have maintained the savanna. However, our results propose that climate change is the main driving factor for the formation of the coastal savanna in this region. Our results also show that the early Holocene sea level rise established mangroves near the study site until 7500 cal yr BP and promoted swamp formation in

  18. Advancing Environmental Flow Science: Developing Frameworks for Altered Landscapes and Integrating Efforts Across Disciplines

    DOE PAGES

    Brewer, Shannon; McManamay, Ryan A.; Miller, Andrew D.; ...

    2016-05-13

    Environmental flows represent a legal mechanism to balance existing and future water uses and sustain non-use values. Here, we identify current challenges, provide examples where they are important, and suggest research advances that would benefit environmental flow science. Specifically, environmental flow science would benefit by (1) developing approaches to address streamflow needs in highly modified landscapes where historic flows do not provide reasonable comparisons, (2) integrating water quality needs where interactions are apparent with quantity but not necessarily the proximate factor of the ecological degradation, especially as frequency and magnitudes of inflows to bays and estuaries, (3) providing a bettermore » understanding of the ecological needs of native species to offset the often unintended consequences of benefiting non-native species or their impact on flows, (4) improving our understanding of the non-use economic value to balance consumptive economic values, and (5) increasing our understanding of the stakeholder socioeconomic spatial distribution of attitudes and perceptions across the landscape. Environmental flow science is still an emerging interdisciplinary field and by integrating socioeconomic disciplines and developing new frameworks to accommodate our altered landscapes, we should help advance environmental flow science and likely increase successful implementation of flow standards.« less

  19. Advancing Environmental Flow Science: Developing Frameworks for Altered Landscapes and Integrating Efforts Across Disciplines

    SciTech Connect

    Brewer, Shannon; McManamay, Ryan A.; Miller, Andrew D.; Mollenhauer, Robert; Worthington, Thomas A.; Arsuffi, Tom

    2016-05-13

    Environmental flows represent a legal mechanism to balance existing and future water uses and sustain non-use values. Here, we identify current challenges, provide examples where they are important, and suggest research advances that would benefit environmental flow science. Specifically, environmental flow science would benefit by (1) developing approaches to address streamflow needs in highly modified landscapes where historic flows do not provide reasonable comparisons, (2) integrating water quality needs where interactions are apparent with quantity but not necessarily the proximate factor of the ecological degradation, especially as frequency and magnitudes of inflows to bays and estuaries, (3) providing a better understanding of the ecological needs of native species to offset the often unintended consequences of benefiting non-native species or their impact on flows, (4) improving our understanding of the non-use economic value to balance consumptive economic values, and (5) increasing our understanding of the stakeholder socioeconomic spatial distribution of attitudes and perceptions across the landscape. Environmental flow science is still an emerging interdisciplinary field and by integrating socioeconomic disciplines and developing new frameworks to accommodate our altered landscapes, we should help advance environmental flow science and likely increase successful implementation of flow standards.

  20. Advancing environmental flow science: Developing frameworks for altered landscapes and integrating efforts across disciplines.

    USGS Publications Warehouse

    Brewer, Shannon K.; McManamay, Ryan A.; Miller, Andrew D.; Mollenhauer, Robert; Worthington, Thomas A.; Arsuffi, Tom

    2016-01-01

    Environmental flows represent a legal mechanism to balance existing and future water uses and sustain non-use values. Here, we identify current challenges, provide examples where they are important, and suggest research advances that would benefit environmental flow science. Specifically, environmental flow science would benefit by (1) developing approaches to address streamflow needs in highly modified landscapes where historic flows do not provide reasonable comparisons, (2) integrating water quality needs where interactions are apparent with quantity but not necessarily the proximate factor of the ecological degradation, especially as frequency and magnitudes of inflows to bays and estuaries, (3) providing a better understanding of the ecological needs of native species to offset the often unintended consequences of benefiting non-native species or their impact on flows, (4) improving our understanding of the non-use economic value to balance consumptive economic values, and (5) increasing our understanding of the stakeholder socioeconomic spatial distribution of attitudes and perceptions across the landscape. Environmental flow science is still an emerging interdisciplinary field and by integrating socioeconomic disciplines and developing new frameworks to accommodate our altered landscapes, we should help advance environmental flow science and likely increase successful implementation of flow standards.

  1. Advancing Environmental Flow Science: Developing Frameworks for Altered Landscapes and Integrating Efforts Across Disciplines.

    PubMed

    Brewer, Shannon K; McManamay, Ryan A; Miller, Andrew D; Mollenhauer, Robert; Worthington, Thomas A; Arsuffi, Tom

    2016-08-01

    Environmental flows represent a legal mechanism to balance existing and future water uses and sustain non-use values. Here, we identify current challenges, provide examples where they are important, and suggest research advances that would benefit environmental flow science. Specifically, environmental flow science would benefit by (1) developing approaches to address streamflow needs in highly modified landscapes where historic flows do not provide reasonable comparisons, (2) integrating water quality needs where interactions are apparent with quantity but not necessarily the proximate factor of the ecological degradation, especially as frequency and magnitudes of inflows to bays and estuaries, (3) providing a better understanding of the ecological needs of native species to offset the often unintended consequences of benefiting non-native species or their impact on flows, (4) improving our understanding of the non-use economic value to balance consumptive economic values, and (5) increasing our understanding of the stakeholder socioeconomic spatial distribution of attitudes and perceptions across the landscape. Environmental flow science is still an emerging interdisciplinary field and by integrating socioeconomic disciplines and developing new frameworks to accommodate our altered landscapes, we should help advance environmental flow science and likely increase successful implementation of flow standards.

  2. Effects of climate and landscape development on the terrestrial phosphorus cycle

    NASA Astrophysics Data System (ADS)

    Filippelli, Gabriel M.; Souch, Catherine

    1999-02-01

    Past variations in the terrestrial cycle of phosphorus (P), a biolimiting nutrient, are poorly understood. Detailed geochemical analysis of P in lake-sediment cores spanning the late Pleistocene to the present from the western Appalachian Plateau, the Coast Mountains of British Columbia, and the San Bernardino Mountains of southern California reveal large changes in terrestrial P cycling. P is transformed from a mineralized form to more bioavailable forms with increased soil development and landscape stability in the catchments. This process occurs relatively rapidly (i.e., within 3000 5000 yr) and can be reset quickly; the degree of transformation depends on local climate and the starting point of the soil system. The release of solid-phase P from these landscapes follows modeled patterns of high rates during the initial stages of soil development and low rates upon soil and landscape stabilization. Changes in weathering style were confirmed for the southern California catchment by analysis of Ge/Si ratios of lake diatoms, which revealed substantially higher values during an interval of high P release and low values at present. These records point to significant variability in the terrestrial P mass balance on glacial time scales, a feature that needs to be incorporated into models of nutrient and carbon cycling in the past.

  3. Advancing Environmental Flow Science: Developing Frameworks for Altered Landscapes and Integrating Efforts Across Disciplines

    NASA Astrophysics Data System (ADS)

    Brewer, Shannon K.; McManamay, Ryan A.; Miller, Andrew D.; Mollenhauer, Robert; Worthington, Thomas A.; Arsuffi, Tom

    2016-08-01

    Environmental flows represent a legal mechanism to balance existing and future water uses and sustain non-use values. Here, we identify current challenges, provide examples where they are important, and suggest research advances that would benefit environmental flow science. Specifically, environmental flow science would benefit by (1) developing approaches to address streamflow needs in highly modified landscapes where historic flows do not provide reasonable comparisons, (2) integrating water quality needs where interactions are apparent with quantity but not necessarily the proximate factor of the ecological degradation, especially as frequency and magnitudes of inflows to bays and estuaries, (3) providing a better understanding of the ecological needs of native species to offset the often unintended consequences of benefiting non-native species or their impact on flows, (4) improving our understanding of the non-use economic value to balance consumptive economic values, and (5) increasing our understanding of the stakeholder socioeconomic spatial distribution of attitudes and perceptions across the landscape. Environmental flow science is still an emerging interdisciplinary field and by integrating socioeconomic disciplines and developing new frameworks to accommodate our altered landscapes, we should help advance environmental flow science and likely increase successful implementation of flow standards.

  4. Advancing Environmental Flow Science: Developing Frameworks for Altered Landscapes and Integrating Efforts Across Disciplines

    SciTech Connect

    Brewer, Shannon; McManamay, Ryan A.; Miller, Andrew D.; Mollenhauer, Robert; Worthington, Thomas A.; Arsuffi, Tom

    2016-05-13

    Environmental flows represent a legal mechanism to balance existing and future water uses and sustain non-use values. Here, we identify current challenges, provide examples where they are important, and suggest research advances that would benefit environmental flow science. Specifically, environmental flow science would benefit by (1) developing approaches to address streamflow needs in highly modified landscapes where historic flows do not provide reasonable comparisons, (2) integrating water quality needs where interactions are apparent with quantity but not necessarily the proximate factor of the ecological degradation, especially as frequency and magnitudes of inflows to bays and estuaries, (3) providing a better understanding of the ecological needs of native species to offset the often unintended consequences of benefiting non-native species or their impact on flows, (4) improving our understanding of the non-use economic value to balance consumptive economic values, and (5) increasing our understanding of the stakeholder socioeconomic spatial distribution of attitudes and perceptions across the landscape. Environmental flow science is still an emerging interdisciplinary field and by integrating socioeconomic disciplines and developing new frameworks to accommodate our altered landscapes, we should help advance environmental flow science and likely increase successful implementation of flow standards.

  5. Basement Fracturing and Weathering On- and Offshore Norway - Genesis, Age, and Landscape Development

    NASA Astrophysics Data System (ADS)

    Knies, J.; van der Lelij, R.; Faust, J.; Scheiber, T.; Broenner, M.; Fredin, O.; Mueller, A.; Viola, G.

    2014-12-01

    Saprolite remnants onshore Scandinavia have been investigated only sporadically. The nature and age of the deeply weathered material thus remains only loosely constrained. The type and degree of weathering of in situ weathered soils are indicative of the environmental conditions during their formation. When external forcing changes, properties related to previous weathering conditions are usually preserved, for example in clay mineral assemblages. By constraining the age and rate of weathering onshore and by isotopically dating selected faults determined to be intimately linked to weathered basement blocks, the influence of climate development, brittle deformation and landscape processes on weathering can be quantified. The "BASE" project aims to establish a temporal and conceptual framework for brittle tectonics, weathering patterns and landscape evolution affecting the basement onshore and offshore Norway. We will study the formation of saprolite in pre-Quaternary times, the influence of deep weathering on landscape development and establish a conceptual structural template of the evolution of the brittle deformational features that are exposed on onshore (weathered) basement blocks. Moreover, saprolitic material may have been eroded and preserved along the Norwegian continental margin during Cenozoic times. By studying both the onshore remnants and offshore erosional products deposited during periods of extreme changes of climate and tectonic boundary conditions (e..g Miocene-Pliocene), new inferences on the timing and controlling mechanisms of denudation, and on the relevance of deep weathering on Late Cenozoic global cooling can be drawn.

  6. Fuel model selection for BEHAVE in midwestern oak savannas

    USGS Publications Warehouse

    Grabner, K.W.; Dwyer, J.P.; Cutter, B.E.

    2001-01-01

    BEHAVE, a fire behavior prediction system, can be a useful tool for managing areas with prescribed fire. However, the proper choice of fuel models can be critical in developing management scenarios. BEHAVE predictions were evaluated using four standardized fuel models that partially described oak savanna fuel conditions: Fuel Model 1 (Short Grass), 2 (Timber and Grass), 3 (Tall Grass), and 9 (Hardwood Litter). Although all four models yielded regressions with R2 in excess of 0.8, Fuel Model 2 produced the most reliable fire behavior predictions.

  7. Caves, Carbonates and Climate: Karst Landscape Development through Environmental Forcing, Little Cayman Island

    NASA Astrophysics Data System (ADS)

    Hsia, S.; Ouellette, G., Jr.; Manfrino, C.

    2016-12-01

    The Cayman Islands are situated in the west-central Caribbean Sea, between Cuba and the Yucatan Peninsula. Little Cayman Island (LCI) is relatively underdeveloped and understudied in comparison to its sister islands, Grand Cayman and Cayman Brac, and hosts less than 200 permanent residents over a 30 square kilometer area. However, like its sister islands, LCI is a small carbonate platform derived from reef building during the Oligocene, Miocene, and Quaternary. The shared geologic history of the Cayman Islands along with minimal human disturbance makes LCI an ideal site to study an island karst landscape. Conduction of field surveys, stratigraphic and petrologic comparisons between primary lithologic formations, and compilation of a geospatial inventory of karst features and lithology of LCI using GIS revealed novel insights into landscape evolution on LCI. In addition to surface karst surveys, several caves on the island were mapped. Cave morphologies suggest that evolution of LCI karst features have been driven by both hydroclimate, as well as salt and freshwater mixing, modulated by sea level fluctuations. These findings are mirrored in the lithology of partially dolomitized Miocene carbonates, which contain paleo-karst fill features and reveal hydroclimate influence, as well as enhanced resistance to dissolution in the present day, ostensibly from submersion in Mg-rich sea waters prior to the Quaternary. These findings shed light on the complex relationship of climate, geology, and karst landscape development on this particular carbonate island. This information is critical in anticipating structural and hydrogeological integrity on LCI under future climate change scenarios and serves as an example of the interplay linking climate and geologic processes to karst landscape development on small carbonate islands.

  8. Eddy Flux and Leaf-level Measurements of Biogenic VOC Emissions from two Savannas in Southern Africa

    NASA Astrophysics Data System (ADS)

    Greenberg, J.; Guenther, A.; Harley, P.; Otter, L.; Veenendaal, E.; Hewitt, N.; James, T.; Owens, S.

    2001-12-01

    Biogenic volatile organic compound (BVOC) emissions of isoprene and terpenes were measured in 2 savannas of southern Africa: a mopane woodland (>95% Colophospermum mopane), near Maun, Botswana and a Combretum savanna (45% Combretum apiculatum, the remainder mostly Acacia nilotica, Zizphus mucronata, Sclerocarya birrea, Grewia bicolor, and Acacia nigrescens), near Skukuza, Republic of South Africa. These 2 landscapes contain most of the dominant woody plant species found in southern Africa; mopane woodlands are a monospecific landscape occurring over a large area across southern Africa. These studies were made in January-February 2001 as part of SAFARI 2000. Over 100 species were examined at the leaf level using cuvette techniques. In addition, relaxed eddy accumulation measurements of BVOC fluxes were made on towers in each location. Large, light dependent emissions of terpenes (mostly alpha-pinene) were observed from mopane. Of the major species in the Combretum savanna, only Acacia nigrescens emitted significant amounts of isoprene; none emitted terpenes. However, several minor species (Lonchocarpus capassa, Spirostachys africana) emitted isoprene. Net CO2 emissions were measured simultaneously on each tower; the diurnal BVOC emissions were integrated and compared with net CO2 flux measurements made simultaneously on the same tower. The contribution of these and other BVOC emissions to net ecosystem carbon exchange will be discussed. In addition, the implications of these emissions to regional atmospheric chemistry and landscape change will be examined.

  9. Restoration of temperate savannas and woodlands

    Treesearch

    Brice B. Hanberry; John M. Kabrick; Peter W. Dunwiddie; Tibor Hartel; Theresa B. Jain; Benjamin O. Knapp

    2017-01-01

    Savannas and woodlands are open forest phases that occur along a gradient between grasslands and closed canopy forests. These ecosystems are characterized by open to nearly closed canopies of overstorey trees, relatively sparse midstorey and understorey woody vegetation, and dense, species-rich ground flora. In contrast to closed forests, the dominant and codominant...

  10. Restoration of midwestern oak woodlands and savannas

    Treesearch

    Dan C. Dey; John M. Kabrick

    2015-01-01

    There are various definitions for savanna and woodland in the ecological literature. Characteristic elements of each community are broadly defined and often overlap according to the authorities (Curtis 1959; Nuzzo 1986; Nelson 2010). Some confusion is inevitable when categorizing what is in reality a continuum of states from prairie to forest in which there can be much...

  11. Tree-grass competition for soil water in arid and semiarid savannas: The role of rainfall intermittency

    NASA Astrophysics Data System (ADS)

    D'Onofrio, Donatella; Baudena, Mara; D'Andrea, Fabio; Rietkerk, Max; Provenzale, Antonello

    2015-01-01

    Arid and semiarid savannas are characterized by the coexistence of trees and grasses in water limited conditions. As in all dry lands, also in these savannas rainfall is highly intermittent. In this work, we develop and use a simple implicit-space model to conceptually explore how precipitation intermittency influences tree-grass competition and savanna occurrence. The model explicitly includes soil moisture dynamics, and life-stage structure of the trees. Assuming that water availability affects the ability of both plant functional types to colonize new space and that grasses outcompete tree seedlings, the model is able to predict the expected sequence of grassland, savanna, and forest along a range of mean annual rainfall. In addition, rainfall intermittency allows for tree-grass coexistence at lower mean annual rainfall values than for constant precipitation. Comparison with observations indicates that the model, albeit very simple, is able to capture some of the essential dynamical processes of natural savannas. The results suggest that precipitation intermittency affects savanna occurrence and structure, indicating a new point of view for reanalyzing observational data from the literature.

  12. The water relations of two evergreen tree species in a karst savanna.

    PubMed

    Schwinning, Susanne

    2008-12-01

    The ecohydrology of karst has not received much attention, despite the disproportionally large contribution of karst aquifers to freshwater supplies. Karst savannas, like many savannas elsewhere, are encroached by woody plants, with possibly negative consequences on aquifer recharge. However, the role of savanna tree species in hydrological processes remains unclear, not least because the location and water absorption zones of tree roots in the spatially complex subsurface strata are unknown. This study examined the water sources and water relations of two savanna trees, Quercus fusiformis (Small) and Juniperus ashei (Buchholz) in the karst region of the eastern Edwards Plateau, Texas (USA). Stable isotope analysis of stem water revealed that both species took up evaporatively enriched water during the warm season, suggesting a relatively shallow water source in the epikarst, the transition zone between soil and bedrock. Q. fusiformis had consistently higher predawn water potentials than J. ashei during drought, and thus was probably deeper-rooted and less capable of maintaining gas exchange at low water potentials. Although the water potential of both species recovered after drought-breaking spring and summer rain events, associated shifts in stem water isotope ratios did not indicate significant uptake of rainwater from the shallow soil. A hypothesis is developed to explain this phenomenon invoking a piston-flow mechanism that pushes water stored in macropores into the active root zones of the trees. Epikarst structure varied greatly with parent material and topography, and had strong effects on seasonal fluctuations in plant water status. The study suggests that tree species of the Edwards Plateau do not commonly reduce aquifer recharge by tapping directly into perched water tables, but more likely by reducing water storage in the epikarst. A more general conclusion is that models of savanna water relations based on Walter's two-layer model may not apply

  13. Predicted avian responses to bioenergy development scenarios in an intensive agricultural landscape

    USGS Publications Warehouse

    Uden, Daniel R.; Allen, Craig R.; Mitchell, Rob B.; McCoy, Tim D.; Guan, Qingfeng

    2015-01-01

    Conversion of native prairie to agriculture has increased food and bioenergy production but decreased wildlife habitat. However, enrollment of highly erodible cropland in conservation programs has compensated for some grassland loss. In the future, climate change and production of second-generation perennial biofuel crops could further transform agricultural landscapes and increase or decrease grassland area. Switchgrass (Panicum virgatum) is an alternative biofuel feedstock that may be economically and environmentally superior to maize (Zea mays) grain for ethanol production on marginally productive lands. Switchgrass could benefit farmers economically and increase grassland area, but there is uncertainty as to how conversions between rowcrops, switchgrass monocultures and conservation grasslands might occur and affect wildlife. To explore potential impacts on grassland birds, we developed four agricultural land-use change scenarios for an intensively cultivated landscape, each driven by potential future climatic changes and ensuing irrigation limitations, ethanol demand, commodity prices, and continuation of a conservation program. For each scenario, we calculated changes in area for landcover classes and predicted changes in grassland bird abundances. Overall, birds responded positively to the replacement of rowcrops with switchgrass and negatively to the conversion of conservation grasslands to switchgrass or rowcrops. Landscape context and interactions between climate, crop water use, and irrigation availability could influence future land-use, and subsequently, avian habitat quality and quantity. Switchgrass is likely to provide higher quality avian habitat than rowcrops but lower quality habitat than conservation grasslands, and therefore, may most benefit birds in heavily cultivated, irrigation dependent landscapes under warmer and drier conditions, where economic profitability may also encourage conversions to drought tolerant bioenergy feedstocks.

  14. Inhabiting the sexual landscape: toward an interpretive theory of the development of sexual orientation and identity.

    PubMed

    Gordon, Liahna E; Silva, Tony J

    2015-01-01

    Building on Paula Rust's (1996) concept of a sexual landscape, we propose an interpretive theory of the development of both sexual orientation and sexual identity. We seek to reconcile human agency with active and shifting influences in social context and to recognize the inherent complexity of environmental factors while acknowledging the role that biological potential plays. We ground our model in the insights of three compatible and related theoretical perspectives: social constructionism, symbolic interactionism, and scripting theory. Within this framework, we explain how sexual orientation and sexual identities develop and potentially change.

  15. Bud protection: a key trait for species sorting in a forest-savanna mosaic.

    PubMed

    Charles-Dominique, Tristan; Beckett, Heath; Midgley, Guy F; Bond, William J

    2015-09-01

    Contrasting fire regimes maintain patch mosaics of savanna, thicket and forest biomes in many African subtropical landscapes. Species dominating each biome are thus expected to display distinct fire-related traits, commonly thought to be bark related. Recent Australian savanna research suggests that bud position, not bark protection alone, determines fire resilience via resprouting. We tested first how bud position influences resprouting ability in 17 tree species. We then compared the effect of both bark-related protection and bud position on the distribution of 63 tree species in 253 transects in all three biomes. Tree species with buds positioned deep under bark had a higher proportion of post-fire aboveground shoot resprouting. Species with low bud protection occurred in fire-prone biomes only if they could root-sucker. The effect of bud protection was supported by a good relationship between species bud protection and distribution across a gradient of fire frequency. Bud protection and high bark production are required to survive frequent fires in savanna. Forests are fire refugia hosting species with little or no bud protection and thin bark. Root-suckering species occur in the three biomes, suggesting that fire is not the only factor filtering this functional type.

  16. Modeling the Distribution of Migratory Bird Stopovers to Inform Landscape-Scale Siting of Wind Development

    PubMed Central

    Pocewicz, Amy; Estes-Zumpf, Wendy A.; Andersen, Mark D.; Copeland, Holly E.; Keinath, Douglas A.; Griscom, Hannah R.

    2013-01-01

    Conservation of migratory birds requires understanding the distribution of and potential threats to their migratory habitats. However, although migratory birds are protected under international treaties, few maps have been available to represent migration at a landscape scale useful to target conservation efforts or inform the siting of wind energy developments that may affect migratory birds. To fill this gap, we developed models that predict where four groups of birds concentrate or stopover during their migration through the state of Wyoming, USA: raptors, wetland, riparian and sparse grassland birds. The models were based on existing literature and expert knowledge concerning bird migration behavior and ecology and validated using expert ratings and known occurrences. There was significant agreement between migratory occurrence data and migration models for all groups except raptors, and all models ranked well with experts. We measured the overlap between the migration concentration models and a predictive model of wind energy development to assess the potential exposure of migratory birds to wind development and illustrate the utility of migratory concentration models for landscape-scale planning. Wind development potential is high across 15% of Wyoming, and 73% of this high potential area intersects important migration concentration areas. From 5.2% to 18.8% of each group’s important migration areas was represented within this high wind potential area, with the highest exposures for sparse grassland birds and the lowest for riparian birds. Our approach could be replicated elsewhere to fill critical data gaps and better inform conservation priorities and landscape-scale planning for migratory birds. PMID:24098379

  17. Modeling the distribution of migratory bird stopovers to inform landscape-scale siting of wind development.

    PubMed

    Pocewicz, Amy; Estes-Zumpf, Wendy A; Andersen, Mark D; Copeland, Holly E; Keinath, Douglas A; Griscom, Hannah R

    2013-01-01

    Conservation of migratory birds requires understanding the distribution of and potential threats to their migratory habitats. However, although migratory birds are protected under international treaties, few maps have been available to represent migration at a landscape scale useful to target conservation efforts or inform the siting of wind energy developments that may affect migratory birds. To fill this gap, we developed models that predict where four groups of birds concentrate or stopover during their migration through the state of Wyoming, USA: raptors, wetland, riparian and sparse grassland birds. The models were based on existing literature and expert knowledge concerning bird migration behavior and ecology and validated using expert ratings and known occurrences. There was significant agreement between migratory occurrence data and migration models for all groups except raptors, and all models ranked well with experts. We measured the overlap between the migration concentration models and a predictive model of wind energy development to assess the potential exposure of migratory birds to wind development and illustrate the utility of migratory concentration models for landscape-scale planning. Wind development potential is high across 15% of Wyoming, and 73% of this high potential area intersects important migration concentration areas. From 5.2% to 18.8% of each group's important migration areas was represented within this high wind potential area, with the highest exposures for sparse grassland birds and the lowest for riparian birds. Our approach could be replicated elsewhere to fill critical data gaps and better inform conservation priorities and landscape-scale planning for migratory birds.

  18. Methods for the quantification of GHG emissions at the landscape level for developing countries in smallholder contexts

    NASA Astrophysics Data System (ADS)

    Milne, Eleanor; Neufeldt, Henry; Rosenstock, Todd; Smalligan, Mike; Cerri, Carlos Eduardo; Malin, Daniella; Easter, Mark; Bernoux, Martial; Ogle, Stephen; Casarim, Felipe; Pearson, Timothy; Bird, David Neil; Steglich, Evelyn; Ostwald, Madelene; Denef, Karolien; Paustian, Keith

    2013-03-01

    Landscape scale quantification enables farmers to pool resources and expertise. However, the problem remains of how to quantify these gains. This article considers current greenhouse gas (GHG) quantification methods that can be used in a landscape scale analysis in terms of relevance to areas dominated by smallholders in developing countries. In landscape scale carbon accounting frameworks, measurements are an essential element. Sampling strategies need careful design to account for all pools/fluxes and to ensure judicious use of resources. Models can be used to scale-up measurements and fill data gaps. In recent years a number of accessible models and calculators have been developed which can be used at the landscape scale in developing country areas. Some are based on the Intergovernmental Panel on Climate Change (IPCC) method and others on dynamic ecosystem models. They have been developed for a range of different purposes and therefore vary in terms of accuracy and usability. Landscape scale assessments of GHGs require a combination of ground sampling, use of data from census, remote sensing (RS) or other sources and modelling. Fitting of all of these aspects together needs to be performed carefully to minimize uncertainties and maximize the use of scarce resources. This is especially true in heterogeneous landscapes dominated by smallholders in developing countries.

  19. Wyoming Landscape Conservation Initiative—A case study in partnership development

    USGS Publications Warehouse

    D'Erchia, Frank

    2016-10-21

    The Wyoming Landscape Conservation Initiative (WLCI) is a successful example of collaboration between science and natural resource management at the landscape scale. In southwestern Wyoming, expanding energy and mineral development, urban growth, and other changes in land use over recent decades, combined with landscape-scale drivers such as climate change and invasive species, have presented compelling challenges to resource managers and a diverse group of Federal, State, industry, and non-governmental organizations, as well as citizen stakeholders. To address these challenges, the WLCI was established as a collaborative forum and interagency partnership to develop and implement science-based conservation actions. About a decade after being established, this report documents the establishment and history of the WLCI, focusing on the path to success of the initiative and providing insights and details that may be useful in developing similar partnerships in other locations. Not merely retrospective, the elements of the WLCI that are presented herein are still in play, still evolving, and still contributing to the resolution of compelling conservation challenges in the Western United States.The U.S. Geological Survey has developed many successful longstanding partnerships, of which the WLCI is one example.“As the Nation’s largest water, earth, and biological science and civilian mapping agency, the U.S. Geological Survey collects, monitors, analyzes, and provides scientific understanding about natural resource conditions, issues, and problems. The diversity of our scientific expertise enables us to carry out large-scale, multi-disciplinary investigations and provide impartial scientific information to resource managers, planners, and other customers” (U.S. Geological Survey, 2016).

  20. Field Investigations of Landscape Development in southeast Spain for use in Modeling Holocene (8,000 - 1,500 yr) Agropastoral Landuse and Landscape Interactions

    NASA Astrophysics Data System (ADS)

    Dimaggio, E. N.; La Roca, N.; Arrowsmith, J. R.; Diez-Castillo, A.; Bernabeu, J.; Barton, C. M.

    2007-12-01

    Dramatic changes in land use were associated with the rise of agriculture in the mid Holocene in the Mediterranean region. Both the surface properties and the drainage networks were changed. Along with the direct modifications to surface properties (vegetation removal and change, sediment liberation and compaction) and consequent drainage alteration (terracing, canals), up and downstream responses in the watersheds communicated these changes throughout the landscape. The magnitude, rate, and feedbacks with the growing human populations are critical questions in our effort to assess human-landscape interactions. To investigate these relationships, recent field work in the Penaguila Valley in southeast Spain included landform mapping, alluvial deposit description, and sample collection emphasizing areas of active erosion, remnant land surfaces and their relation to archaeological sites. We have updated our geomorphic maps by refining the delineation of alluvial terraces, steep-walled (40m deep) drainages ("barrancos"), and hollows ("barrancos de fondo plano"). Hollows are curved, elongate, flat-bottomed gullies with steep walls (2-30m tall) and extend headward from the main barrancos. This work enables more accurate terrace correlations necessary for both landscape evolution modeling and interpretation of the development history of the basin. Alluvial terraces are crucial to this research because they record periods of past stable topography. In the Penaguila, sites dating back to late Mesolithic and early Neolithic (around 6600 BP) and subsequent periods (Chalcolithic and Bronze Age) are exposed on a prominent terrace surface mapped as Terrace A. This broad low relief surface is scarred by deep barrancos and hollow formation that expose bedrock marls and overlying alluvial deposits. Stratigraphic profiles and texture analyses of Terrace A deposits reveal overland flow facies and channel networks in reworked and CaCO3-encrusted marls, and several organic

  1. Grassland, shrubland and savanna stewardship: where do we go from here?

    USDA-ARS?s Scientific Manuscript database

    Scientific efforts to understand grasslands, shrublands and savannas and thereby develop sustainable management practices are roughly 100 years old. What have we learned in that time? Several assumptions made by scientists and policymakers early in the 20th century have proved mistaken, resulting in...

  2. Ecological Restoration Through Silviculture--A Savanna Management Demonstration Area, Sinkin Experimental Forest, Missouri

    Treesearch

    Edward F. Loewenstein; Kenneth R. Davidson

    2002-01-01

    In 1998, a project was initiated to demonstrate techniques and evaluate the efficacy of reducing overstory tree density and reintroducing fire in order to develop the tree composition, structure, and herbaceous complex typical of a savanna. On three study areas, two dominated by oak and one by shortleaf pine, the total basal area of all trees = 1.6 inches DBH was...

  3. Analytical tool for risk assessment of landscape and urban planning: Spatial development impact assessment

    NASA Astrophysics Data System (ADS)

    Rehak, David; Senovsky, Michail; Balog, Karol; Dvorak, Jiri

    2011-06-01

    This article covers the issue of preventive protection of population, technical infrastructure, and the environment against adverse impacts of careless spatial development. In the first section, we describe the relationship between sustainable development and spatial development. This discussion is followed by a review of the current state of spatial development security, primarily at a national level in the Czech Republic. The remainder of the paper features our original contribution which is a tool for risk assessment in landscape and urban planning, the Spatial Development Impact Assessment (SDIA) tool. We briefly review the most significant semi-quantitative methods of risk analysis that were used as a starting point in implementing the tool, and we discuss several of SDIA's salient features, namely, the assessment process algorithm, the catalogue of hazard and asset groups, and the spatial development impact matrix.

  4. Relationships between brittle deformation, weathering and landscape development during the Mesozoic in Scandinavia

    NASA Astrophysics Data System (ADS)

    Viola, Giulio; Fredin, Ola; Scheiber, Thomas; Brönner, Marco; Zwingmann, Horst; Knies, Jochen

    2015-04-01

    Pre-Quaternary weathering is generally considered responsible for the formation of rather common, yet poorly constrained, saprolite remnants onshore Scandinavia. Understanding the genesis of these weathering products and placing them into an adequate tectonic and climatic framework is currently of great interest for two reasons. First, the origin of the landscape in Scandinavia, where deep weathering is thought to have played a fundamental role, is the subject of a lively debate hinged around the number and age of episodes of regional uplift and denudation. Second, there have been recent discoveries of major hydrocarbon reserves within weathered basement highs in the North Sea immediately offshore Norway. Invariably, these basement highs are also severely fractured and faulted and a genetic relationship between brittle deformation, weathering and landscape development is suggested by a number of observations. Within the recently launched BASE project, we aim to establish a temporal and conceptual framework for brittle tectonics, weathering patterns and landscape evolution by constraining the age and rate of weathering and by isotopically dating selected faults intimately linked to weathered basement blocks. Initial efforts have focused on fractured and weathered granitoid rocks of Caledonian age exposed in western Norway. There, saprolites are found as small pockets within a joint valley landscape, which was likely stripped by Quaternary glaciations. Saprolite distribution is mostly structurally controlled as deep weathering and alteration occur predominantly in association with fractures and along faulted corridors. Structural analysis has allowed the geometric and kinematic interpretation of the exposed fracture and fault patterns and we could assign them to a number of distinct brittle deformation episodes characterised by robust paleostress tensors. The K-Ar dating of illites separated from structurally constrained faults indicates a long strain localization

  5. Ranking Landscape Development Scenarios Affecting Natterjack Toad (Bufo calamita) Population Dynamics in Central Poland

    PubMed Central

    Franz, Kamila W.; Romanowski, Jerzy; Johst, Karin; Grimm, Volker

    2013-01-01

    When data are limited it is difficult for conservation managers to assess alternative management scenarios and make decisions. The natterjack toad (Bufo calamita) is declining at the edges of its distribution range in Europe and little is known about its current distribution and abundance in Poland. Although different landscape management plans for central Poland exist, it is unclear to what extent they impact this species. Based on these plans, we investigated how four alternative landscape development scenarios would affect the total carrying capacity and population dynamics of the natterjack toad. To facilitate decision-making, we first ranked the scenarios according to their total carrying capacity. We used the software RAMAS GIS to determine the size and location of habitat patches in the landscape. The estimated carrying capacities were very similar for each scenario, and clear ranking was not possible. Only the reforestation scenario showed a marked loss in carrying capacity. We therefore simulated metapopulation dynamics with RAMAS taking into account dynamical processes such as reproduction and dispersal and ranked the scenarios according to the resulting species abundance. In this case, we could clearly rank the development scenarios. We identified road mortality of adults as a key process governing the dynamics and separating the different scenarios. The renaturalisation scenario clearly ranked highest due to its decreased road mortality. Taken together our results suggest that road infrastructure development might be much more important for natterjack toad conservation than changes in the amount of habitat in the semi-natural river valley. We gained these insights by considering both the resulting metapopulation structure and dynamics in the form of a PVA. We conclude that the consideration of dynamic processes in amphibian conservation management may be indispensable for ranking management scenarios. PMID:23734223

  6. Ranking landscape development scenarios affecting natterjack toad (Bufo calamita) population dynamics in Central Poland.

    PubMed

    Franz, Kamila W; Romanowski, Jerzy; Johst, Karin; Grimm, Volker

    2013-01-01

    When data are limited it is difficult for conservation managers to assess alternative management scenarios and make decisions. The natterjack toad (Bufo calamita) is declining at the edges of its distribution range in Europe and little is known about its current distribution and abundance in Poland. Although different landscape management plans for central Poland exist, it is unclear to what extent they impact this species. Based on these plans, we investigated how four alternative landscape development scenarios would affect the total carrying capacity and population dynamics of the natterjack toad. To facilitate decision-making, we first ranked the scenarios according to their total carrying capacity. We used the software RAMAS GIS to determine the size and location of habitat patches in the landscape. The estimated carrying capacities were very similar for each scenario, and clear ranking was not possible. Only the reforestation scenario showed a marked loss in carrying capacity. We therefore simulated metapopulation dynamics with RAMAS taking into account dynamical processes such as reproduction and dispersal and ranked the scenarios according to the resulting species abundance. In this case, we could clearly rank the development scenarios. We identified road mortality of adults as a key process governing the dynamics and separating the different scenarios. The renaturalisation scenario clearly ranked highest due to its decreased road mortality. Taken together our results suggest that road infrastructure development might be much more important for natterjack toad conservation than changes in the amount of habitat in the semi-natural river valley. We gained these insights by considering both the resulting metapopulation structure and dynamics in the form of a PVA. We conclude that the consideration of dynamic processes in amphibian conservation management may be indispensable for ranking management scenarios.

  7. Shifts on reproductive phenology of tropical cerrado savanna trees and climate changes

    NASA Astrophysics Data System (ADS)

    Morellato, Patricia

    2010-05-01

    Phenology is the study of cyclic biological events and its relationship to abiotic factors. Timing of flowering, fruiting and leafing is highly correlated to environmental factors such as temperature, precipitation, irradiance and isolation. Accordingly, any change in these factors may have a direct effect on the initiation, intensity and duration of different phenophases. Tropical phenology has not contributed much for climatic change research since historical data sets are scarce and the absence of sharp seasons and distinct factors driving phenology makes difficult the detection of changes over time. One way to have insights on climate driven phenology shifts on tropical plants is through the comparison of plant phenology under different environmental conditions. Fragmentation of natural landscape has exposed plants to edge effects - the interaction between two adjacent ecosystems, when the two are separated by an abrupt transition - the edge, including both abiotic and biological changes on environmental conditions that likely affect plant phenology. The microclimatic conditions along edges have important direct biological effects on the reproductive phenology and fitness of plant species. One can expected that the abiotic edge effects on plant phenology may be similar to some extent to certain effects induced by climate change on plant phenology since both involve shifts on environmental conditions. Due to the threatened status and rich biodiversity of Brazilian Neotropical savanna, or the Brazilian Cerrado, the present study aimed to understand edge effects on cerrado savanna species. We compared micro environmental factors and phenology of several species on the edge and in the interior of cerrado savanna. Our first results indicated that shifts on the micro environmental condition may have driven changes in time, duration and intensity of species phenology and may give us insights on savanna responses to climate changes.

  8. Window area and development drive spatial variation in bird-window collisions in an urban landscape.

    PubMed

    Hager, Stephen B; Cosentino, Bradley J; McKay, Kelly J; Monson, Cathleen; Zuurdeeg, Walt; Blevins, Brian

    2013-01-01

    Collisions with windows are an important human-related threat to birds in urban landscapes. However, the proximate drivers of collisions are not well understood, and no study has examined spatial variation in mortality in an urban setting. We hypothesized that the number of fatalities at buildings varies with window area and habitat features that influence avian community structure. In 2010 we documented bird-window collisions (BWCs) and characterized avian community structure at 20 buildings in an urban landscape in northwestern Illinois, USA. For each building and season, we conducted 21 daily surveys for carcasses and nine point count surveys to estimate relative abundance, richness, and diversity. Our sampling design was informed by experimentally estimated carcass persistence times and detection probabilities. We used linear and generalized linear mixed models to evaluate how habitat features influenced community structure and how mortality was affected by window area and factors that correlated with community structure. The most-supported model was consistent for all community indices and included effects of season, development, and distance to vegetated lots. BWCs were related positively to window area and negatively to development. We documented mortalities for 16/72 (22%) species (34 total carcasses) recorded at buildings, and BWCs were greater for juveniles than adults. Based on the most-supported model of BWCs, the median number of annual predicted fatalities at study buildings was 3 (range = 0-52). These results suggest that patchily distributed environmental resources and levels of window area in buildings create spatial variation in BWCs within and among urban areas. Current mortality estimates place little emphasis on spatial variation, which precludes a fundamental understanding of the issue. To focus conservation efforts, we illustrate how knowledge of the structural and environmental factors that influence bird-window collisions can be used to

  9. Window Area and Development Drive Spatial Variation in Bird-Window Collisions in an Urban Landscape

    PubMed Central

    Hager, Stephen B.; Cosentino, Bradley J.; McKay, Kelly J.; Monson, Cathleen; Zuurdeeg, Walt; Blevins, Brian

    2013-01-01

    Collisions with windows are an important human-related threat to birds in urban landscapes. However, the proximate drivers of collisions are not well understood, and no study has examined spatial variation in mortality in an urban setting. We hypothesized that the number of fatalities at buildings varies with window area and habitat features that influence avian community structure. In 2010 we documented bird-window collisions (BWCs) and characterized avian community structure at 20 buildings in an urban landscape in northwestern Illinois, USA. For each building and season, we conducted 21 daily surveys for carcasses and nine point count surveys to estimate relative abundance, richness, and diversity. Our sampling design was informed by experimentally estimated carcass persistence times and detection probabilities. We used linear and generalized linear mixed models to evaluate how habitat features influenced community structure and how mortality was affected by window area and factors that correlated with community structure. The most-supported model was consistent for all community indices and included effects of season, development, and distance to vegetated lots. BWCs were related positively to window area and negatively to development. We documented mortalities for 16/72 (22%) species (34 total carcasses) recorded at buildings, and BWCs were greater for juveniles than adults. Based on the most-supported model of BWCs, the median number of annual predicted fatalities at study buildings was 3 (range = 0–52). These results suggest that patchily distributed environmental resources and levels of window area in buildings create spatial variation in BWCs within and among urban areas. Current mortality estimates place little emphasis on spatial variation, which precludes a fundamental understanding of the issue. To focus conservation efforts, we illustrate how knowledge of the structural and environmental factors that influence bird-window collisions can be used

  10. Disturbance Frequency Determines Morphology and Community Development in Multi-Species Biofilm at the Landscape Scale

    PubMed Central

    Milferstedt, Kim; Santa-Catalina, Gaëlle; Godon, Jean-Jacques; Escudié, Renaud; Bernet, Nicolas

    2013-01-01

    Many natural and engineered biofilm systems periodically face disturbances. Here we present how the recovery time of a biofilm between disturbances (expressed as disturbance frequency) shapes the development of morphology and community structure in a multi-species biofilm at the landscape scale. It was hypothesized that a high disturbance frequency favors the development of a stable adapted biofilm system while a low disturbance frequency promotes a dynamic biofilm response. Biofilms were grown in laboratory-scale reactors over a period of 55-70 days and exposed to the biocide monochloramine at two frequencies: daily or weekly pulse injections. One untreated reactor served as control. Biofilm morphology and community structure were followed on comparably large biofilm areas at the landscape scale using automated image analysis (spatial gray level dependence matrices) and community fingerprinting (single-strand conformation polymorphisms). We demonstrated that a weekly disturbed biofilm developed a resilient morphology and community structure. Immediately after the disturbance, the biofilm simplified but recovered its initial complex morphology and community structure between two biocide pulses. In the daily treated reactor, one organism largely dominated a morphologically simple and stable biofilm. Disturbances primarily affected the abundance distribution of already present bacterial taxa but did not promote growth of previously undetected organisms. Our work indicates that disturbances can be used as lever to engineer biofilms by maintaining a biofilm between two developmental states. PMID:24303024

  11. Management and development of land in the name of the Green Economy: planning, landscape, efficiency, biodiversity

    NASA Astrophysics Data System (ADS)

    Benvenuti, Paolo

    2016-04-01

    Promoting sustainable economic development is the basis of the Green Economy: a new vision of Agriculture, Environmental and Regional policy, shared by the wine sector, especially on some crucial issues, such as reducing the consumption of agricultural land, recognition as economically important of the green agricultural production space, spreading of organic farming, adoption of good agricultural practices. Sustainability, in fact , is not just about the use of analysis tools (carbonfoot print, Waterfoot print, etc .) but is about innovations to be introduced in the entire production process, protection of biodiversity, ethic work in the vineyard and winery. It means to disseminate as much as possible all those practices that can enable a more efficient land management also considering the recent climate changes: introduction of agro-energy and precision agriculture, rational use of water resources, creation of an observatory on temperatures and an interactive mapping system, viticultural zoning and municipal planning to make concrete balance between vitality in agronomic sector and landscape quality. Realizing such a regional geopedological mapping about agricultural soil, will allow companies to display a real-time access to all the data needed for a sustainable management of the funds, not only it would be an important tool to support the technical choices of farmers, enhancing their potential and optimizing production in relation to the current climate crisis, but would have a strong impact in terms of managing and saving water and energy resources. A strong efficacy in this context should be recognized at the "Urban Regulation Plans of the Wine Cities", which have developed since 2007 on the base of the guidelines promoted by the Italian Association Città del Vino, in order to enhance the quality of wine districts. The foundations of this multidisciplinary tool are based on: • in-depth knowledge of the characteristics of the wine territory; • unity and

  12. Examining cultural drifts in artworks through history and development: cultural comparisons between Japanese and western landscape paintings and drawings

    PubMed Central

    Nand, Kristina; Masuda, Takahiko; Senzaki, Sawa; Ishii, Keiko

    2014-01-01

    Research on cultural products suggest that there are substantial cultural variations between East Asian and European landscape masterpieces and contemporary members' landscape artwork (Masuda et al., 2008c), and that these cultural differences in drawing styles emerge around the age of 8 (Senzaki et al., 2014b). However, culture is not static. To explore the dynamics of historical and ontogenetic influence on artistic expressions, we examined (1) 17–20th century Japanese and Western landscape masterpieces, and (2) cross-sectional adolescent data in landscape artworks alongside previous findings of elementary school-aged children, and undergraduates. The results showed cultural variations in artworks and masterpieces as well as substantial “cultural drifts” (Herskovits, 1948) where at certain time periods in history and in development, people's expressions deviated from culturally default patterns but occasionally returned to its previous state. The bidirectional influence of culture and implications for furthering the discipline of cultural psychology will be discussed. PMID:25285085

  13. Examining cultural drifts in artworks through history and development: cultural comparisons between Japanese and western landscape paintings and drawings.

    PubMed

    Nand, Kristina; Masuda, Takahiko; Senzaki, Sawa; Ishii, Keiko

    2014-01-01

    Research on cultural products suggest that there are substantial cultural variations between East Asian and European landscape masterpieces and contemporary members' landscape artwork (Masuda et al., 2008c), and that these cultural differences in drawing styles emerge around the age of 8 (Senzaki et al., 2014b). However, culture is not static. To explore the dynamics of historical and ontogenetic influence on artistic expressions, we examined (1) 17-20th century Japanese and Western landscape masterpieces, and (2) cross-sectional adolescent data in landscape artworks alongside previous findings of elementary school-aged children, and undergraduates. The results showed cultural variations in artworks and masterpieces as well as substantial "cultural drifts" (Herskovits, 1948) where at certain time periods in history and in development, people's expressions deviated from culturally default patterns but occasionally returned to its previous state. The bidirectional influence of culture and implications for furthering the discipline of cultural psychology will be discussed.

  14. Environmental resource management on the Munduruku savanna

    NASA Astrophysics Data System (ADS)

    Sheffler, E. Margaret; Southwick, Edward E.

    1984-05-01

    For 13 years, the Munduruku were observed living in the savanna region located in South America in the Brazilian state of Pará. The area is near the point where the states of Pará, Amazonas, and Mato Grosso join their borders, and is utilized by about 200 300 Munduruku Amerindians. Their subsistence staple is manioc (a cassava), with fruits and meat included in the diet. Gold mining by Brazilians is a disruptive element in the resource management of the savanna habitat on the rim of the Amazon Basin. Direct and indirect results of mining interference are described. A study of the manner in which the Munduruku on the Cururu River (a tributary of the Tapajós) have handled the potentially disruptive rubber tapping suggests possible ways of reversing the interference. Several courses of action are discussed.

  15. Environmental resource management of the Munduruku savanna

    SciTech Connect

    Sheffler, E.M.; Southwick, E.E.

    1984-05-01

    For 13 years, the Munduruku were observed living in the savanna region located in South America in the Brazilian state of Para. The area is near the point where the states of Para, Amazonas, and Mato Grosso join their borders, and is utilized by about 200-300 Munduruku Amerindians. Their subsistence staple is manioc (a cassava), with fruits and meat included in the diet. Gold mining by Brazilians is a disruptive element in the resource management of the savanna habitat on the rim of the Amazon Basin. Direct and indirect results of mining interference are described. A study of the manner in which the Munduruku on the Cururu River (a tributary of the Tapajos) have handled the potentially disruptive rubber tapping suggests possible ways of reversing the interference. Several courses of action are discussed. 14 references, 3 figures, 2 tables.

  16. Detecting animals in African Savanna with UAVs and the crowds

    NASA Astrophysics Data System (ADS)

    Rey, Nicolas; Volpi, Michele; Joost, Stéphane; Tuia, Devis

    2017-10-01

    Unmanned aerial vehicles (UAVs) offer new opportunities for wildlife monitoring, with several advantages over traditional field-based methods. They have readily been used to count birds, marine mammals and large herbivores in different environments, tasks which are routinely performed through manual counting in large collections of images. In this paper, we propose a semi-automatic system able to detect large mammals in semi-arid Savanna. It relies on an animal-detection system based on machine learning, trained with crowd-sourced annotations provided by volunteers who manually interpreted sub-decimeter resolution color images. The system achieves a high recall rate and a human operator can then eliminate false detections with limited effort. Our system provides good perspectives for the development of data-driven management practices in wildlife conservation. It shows that the detection of large mammals in semi-arid Savanna can be approached by processing data provided by standard RGB cameras mounted on affordable fixed wings UAVs.

  17. Crown cover chart for oak savannas. Forest Service technical brief

    SciTech Connect

    Law, J.R.; Johnson, P.S.; Houf, G.

    1994-07-01

    Although oak savannas have been defined in many ways, they are characterized by scattered trees, largely comprised of oaks, and a sparse ground layer rich in grasses and forbs. The crown cover chart can be used to estimate the crown cover of trees as a percent of total area. Potential applications of the chart include monitoring changes in savanna crown cover, determining needed reductions in crown cover, and defining the savanna state. in restoring savannas that have grown into closed canopy stands, one can use the chart to estimate initial crown cover before restoration work is begun and again after crown cover has been reduced.

  18. Seasonal distribution of African savanna fires

    NASA Technical Reports Server (NTRS)

    Cahoon, Donald R., Jr.; Stocks, Brian J.; Levine, Joel S.; Cofer, Wesley R., III; O'Neill, Katherine P.

    1992-01-01

    The temporal and spatial distribution of savanna fires over the entire African continent, as determined from nighttime satellite imagery, is described. It is found that, contrary to expectations, most fires are left to burn uncontrolled, so that there is no strong diurnal cycle in the fire frequency. The knowledge gained from this study regarding the distribution and variability of fires is helpful in the monitoring of climatically important trace gases emitted from burning biomass.

  19. The Cellular and Molecular Landscapes of the Developing Human Central Nervous System

    PubMed Central

    Silbereis, John C.; Pochareddy, Sirisha; Zhu, Ying; Li, Mingfeng; Sestan, Nenad

    2016-01-01

    Summary The human central nervous system follows a pattern of development typical of all mammals, but certain neurodevelopmental features are highly derived. Building the human CNS requires the precise orchestration and coordination of myriad molecular and cellular processes across a staggering array of cell types and over a long period of time. Dysregulation of these processes affects the structure and function of the CNS and can lead to neurological or psychiatric disorders. Recent technological advances and increased focus on human neurodevelopment have enabled a more comprehensive characterization of the human CNS and its development in both health and disease. The aim of this review is to highlight recent advancements in our understanding of the molecular and cellular landscapes of the developing human CNS, with focus on the cerebral neocortex, and the insights these findings provide into human neural evolution, function, and dysfunction. PMID:26796689

  20. Dynamic metropolitan landscapes: Residential development and vegetation change in the U.S

    NASA Astrophysics Data System (ADS)

    Jantz, Patrick Arthur

    Residential development is now a major contributor to land surface change in the U.S. From 1990 - 2000, over thirteen million housing units were added to the nation's housing stock which stood at 102.3 million in 1990. Another 15.8 million housing units were added from 2000 - 2010. Of particular concern is the ongoing increase in low-density residential development because of its large resource footprint and biodiversity impacts. In this dissertation I pose three broad questions 1) What were the trends in residential development in the U.S. from 1990 - 2000? 2) What were the trends in rural conversion to low-density residential use from 1990 - 2000 in the Mid-Atlantic and the Pacific Northwest and what social and environmental factors help explain these trends? 3) What were the effects of rural conversion to residential use on vegetation productivity in the Mid-Atlantic and the Pacific Northwest from 2000 - 2010? To answer these questions I created a database derived from U.S. Census blocks that allows for interdecadal comparison of recent housing density change in support of spatial demographic research. In a series of GIS based analyses I used the database to map changes in metropolitan housing density distributions in the Mid-Atlantic and western Washington regions and used a satellite derived index of vegetation productivity to assess the impacts of housing growth on vegetation carbon uptake. Results indicate that residential housing growth is more dynamic than previously thought and established approaches for mapping housing density tend to underestimate the local intensity of residential change. In the Mid-Atlantic and western Washington, low-density residential development is affecting large fractions of rural landscapes in metropolitan areas. The strongest correlates of low-density conversion of rural landscapes were population growth and extent of protected lands, suggesting future directions for modeling the drivers of rural conversion. Residential

  1. Methane emissions from northern Amazon savanna wetlands and Balbina Reservoir

    NASA Astrophysics Data System (ADS)

    Kemenes, A.; Belger, L.; Forsberg, B.; Melack, J. M.

    2006-12-01

    To improve estimates of methane emission for the Amazon basin requires information from aquatic environments not represented in the central basin near the Solimoes River, where most of the current data were obtained. We have combined intensive, year-long measurements of methane emission and water levels made in interfluvial wetlands located in the upper Negro basin with calculations of inundation based on a time series of Radarsat synthetic aperature radar images. These grass-dominated savannas emitted methane at an average rate of 18 mg C per m squared per day, a low rate compared to the habitats with floating grasses the occur in the Solimoes floodplains. Reservoirs constructed in the Amazon typically flood forested landscapes and lead to conditions conducive for methane production. The methane is released to the atmosphere from the reservoir and as the water exits the turbines and from the downstream river. Balbina Reservoir near Manaus covers about 2400 km squared along the Uatuma River. Annual averages of measurements of methane emission from the various habitats in the reservoir range from 23 to 64 mg C per m squared per day. Total annual emission from the reservoir is about 58 Gg C. In addition, about 39 Gg C per year are released below the dam, about 50 percent of which is released as the water passes through the turbines. On an annual areal basis, Balbina Reservoir emits 40 Mg C km squared, in contrast to 30 Mg km squared for the Solimoes mainstem floodplain

  2. Groundwater uptake by woody vegetation in a semiarid oak savanna

    NASA Astrophysics Data System (ADS)

    Miller, Gretchen R.; Chen, Xingyuan; Rubin, Yoram; Ma, Siyan; Baldocchi, Dennis D.

    2010-10-01

    Groundwater can serve as an important resource for woody vegetation in semiarid landscapes, particularly when soil water is functionally depleted and unavailable to plants. This study examines the uptake of groundwater by deciduous blue oak trees (Quercus douglasii) in a California oak savanna. Here we present a suite of direct and indirect methods that demonstrate its occurrence and quantify its rates. The study site is underlain by a thin soil layer and fractured metavolcanic bedrock. Typical depth to groundwater is approximately 8 m. A variety of water storage and flux measurements were collected from 2005 to 2008, including groundwater levels, soil moisture contents, sap flows, and latent heat fluxes. During the dry season, groundwater uptake rates ranged from 4 to 25 mm month-1 and approximately 80% of total ET during June, July, and August came from groundwater. Leaf and soil water potentials supported these results, indicating that groundwater uptake was thermodynamically favorable over soil water uptake for key portions of the growing season. These findings strongly suggest that blue oaks should be considered obligate phreatophytes and that groundwater reserves provide a buffer to rapid changes in their hydroclimate, if these assets are not otherwise depleted by prolonged drought or human consumption. While groundwater uptake may provide for short-term protection, it should be viewed not as a mechanism for continued plant growth. It allows the woody vegetation to subsist during the summer but not to flourish.

  3. Modeling Gross Primary Production of Savanna Woodlands in Southern Africa Using MODIS Imagery and CO2 Flux Tower Data

    NASA Astrophysics Data System (ADS)

    Jin, C.; Xiao, X.; Merbold, L.; Arneth, A.; Veenendaal, E.; Kutsch, W.

    2012-12-01

    Accurate estimation of gross primary production (GPP) of savanna ecosystem is valuable for evaluating the role of Africa in the global carbon cycle. An eddy flux observation network has been established to continuously measure the net CO2 fluxes (NEE) across various savanna vegetation types in Africa (CarboAfrica). Several publications have reported the seasonal dynamics and interannual variation of GPP for the savanna vegetation through partitioning of the measured NEE data. The satellite-based Production Efficiency Models (PEM), which calculate GPP as the product of absorbed photosynthetically active radiation (PAR) and light use efficiency (LUE), have been developed to scale up in situ GPP estimation from the eddy flux towers to regional scale. In this study, the Vegetation Photosynthesis Model (VPM) and the Moderate Resolution Imaging Spectroradiometer (MODIS) data were evaluated for their capacity to model GPP for savanna woodlands at two eddy flux towers in Botswana and Zambia, respectively. These two sites have different woodland types and precipitation pattern (Mopane woodlands vs. Miombo woodlands, semi-arid vs. semi-humid). In the VPM model, GPP is simulated as the product of photosynthetically active radiation (PAR), air temperature, Enhanced Vegetation Index (EVI), and Land Surface Water Index (LSWI). The results show that the simulated GPP by the VPM track well the temporal dynamic of GPP estimated from the eddy covariance measurements at these two sites. In addition, the land surface phenology of savanna woodlands, described by the satellite vegetation indices, especially the water-sensitive satellite indices-LSWI, are proved to match the phenology based on vegetation physiology activity measured by eddy covariance towers. The information of the timing and duration of vegetation growing season is useful for assisting the VPM modeling. Further evaluation of VPM simulations for and other savanna ecosystems is necessary before the VPM model is applied to

  4. Evaluation of urban sprawl and urban landscape pattern in a rapidly developing region.

    PubMed

    Lv, Zhi-Qiang; Dai, Fu-Qiang; Sun, Cheng

    2012-10-01

    Urban sprawl is a worldwide phenomenon happening particularly in rapidly developing regions. A study on the spatiotemporal characteristics of urban sprawl and urban pattern is useful for the sustainable management of land management and urban land planning. The present research explores the spatiotemporal dynamics of urban sprawl in the context of a rapid urbanization process in a booming economic region of southern China from 1979 to 2005. Three urban sprawl types are distinguished by analyzing overlaid urban area maps of two adjacent study years which originated from the interpretation of remote sensed images and vector land use maps. Landscape metrics are used to analyze the spatiotemporal pattern of urban sprawl for each study period. Study results show that urban areas have expanded dramatically, and the spatiotemporal landscape pattern configured by the three sprawl types changed obviously. The different sprawl type patterns in five study periods have transformed significantly, with their proportions altered both in terms of quantity and of location. The present research proves that urban sprawl quantification and pattern analysis can provide a clear perspective of the urbanization process during a long time period. Particularly, the present study on urban sprawl and sprawl patterns can be used by land use and urban planners.

  5. Circumpolar patterns of ground-fast lake ice and landscape development

    NASA Astrophysics Data System (ADS)

    Bartsch, Annett; Pointner, Georg; Leibmann, Marina; Dvornikov, Yuri; Khomutov, Artem

    2017-04-01

    Shallow lakes in the Arctic are often associated with thermokarst processes which are characteristic for permafrost environments. They partially or completely freeze-up during winter time what can be observed from space using Synthetic Aperture Radar (SAR) data. Spatial patterns of ground-fast and floating ice relate to geomorphological and hydrological processes, but no circumpolar account of this phenomenon is currently available due to challenges when dealing with the varying observation geometry typical for SAR. An approach using ENVISAT ASAR Wide Swath data (approximately 120 m resolution) has been developed supported by bathymetric measurements in Siberia and eventually applied across the entire Arctic for late winter 2008. In total about 2 Million lake objects have been analyzed considering the boundaries of the Last Glacial Maximum, permafrost zones and soil organic carbon content. Distinct patterns of ground-fast lake ice fraction can be found across the Arctic. Clusters of variable fractions of ground-fast ice occur especially in Yedoma regions of Eastern Siberia and Alaska. This reflects the nature of thaw lake dynamics. Analyses of lake depth measurements from several sites (Alaskan North Slope, Richards Island in Canada, Yamal Peninsula and Lena Delta) suggest that the used method yields the potential to utilize ground-fast lake ice information over larger areas with respect to landscape development, but results need to be treated with care, specifically for larger lakes and along river courses. A combination of general lake features and ground-fast ice fraction may lead to an advanced understanding of landscape patterns and development. Ground-fast ice fraction information may support to some extent the identification of landscape units, for example areas of adjacent lakes with similar patterns (terraces) or areas with mixed ground-fast fractions which indicate different lake development stages. This work was supported by the Austrian Science Fund

  6. Comparing the Ecological Impacts of Wind and Oil & Gas Development: A Landscape Scale Assessment

    PubMed Central

    Jones, Nathan F.; Pejchar, Liba

    2013-01-01

    Energy production in the United States is in transition as the demand for clean and domestic power increases. Wind energy offers the benefit of reduced emissions, yet, like oil and natural gas, it also contributes to energy sprawl. We used a diverse set of indicators to quantify the ecological impacts of oil, natural gas, and wind energy development in Colorado and Wyoming. Aerial imagery was supplemented with empirical data to estimate habitat loss, fragmentation, potential for wildlife mortality, susceptibility to invasion, biomass carbon lost, and water resources. To quantify these impacts we digitized the land-use footprint within 375 plots, stratified by energy type. We quantified the change in impacts per unit area and per unit energy produced, compared wind energy to oil and gas, and compared landscapes with and without energy development. We found substantial differences in impacts between energy types for most indicators, although the magnitude and direction of the differences varied. Oil and gas generally resulted in greater impacts per unit area but fewer impacts per unit energy compared with wind. Biologically important and policy-relevant outcomes of this study include: 1) regardless of energy type, underlying land-use matters and development in already disturbed areas resulted in fewer total impacts; 2) the number and source of potential mortality varied between energy types, however, the lack of robust mortality data limits our ability to use this information to estimate and mitigate impacts; and 3) per unit energy produced, oil and gas extraction was less impactful on an annual basis but is likely to have a much larger cumulative footprint than wind energy over time. This rapid evaluation of landscape-scale energy development impacts could be replicated in other regions, and our specific findings can help meet the challenge of balancing land conservation with society’s demand for energy. PMID:24312296

  7. Comparing the ecological impacts of wind and oil & gas development: a landscape scale assessment.

    PubMed

    Jones, Nathan F; Pejchar, Liba

    2013-01-01

    Energy production in the United States is in transition as the demand for clean and domestic power increases. Wind energy offers the benefit of reduced emissions, yet, like oil and natural gas, it also contributes to energy sprawl. We used a diverse set of indicators to quantify the ecological impacts of oil, natural gas, and wind energy development in Colorado and Wyoming. Aerial imagery was supplemented with empirical data to estimate habitat loss, fragmentation, potential for wildlife mortality, susceptibility to invasion, biomass carbon lost, and water resources. To quantify these impacts we digitized the land-use footprint within 375 plots, stratified by energy type. We quantified the change in impacts per unit area and per unit energy produced, compared wind energy to oil and gas, and compared landscapes with and without energy development. We found substantial differences in impacts between energy types for most indicators, although the magnitude and direction of the differences varied. Oil and gas generally resulted in greater impacts per unit area but fewer impacts per unit energy compared with wind. Biologically important and policy-relevant outcomes of this study include: 1) regardless of energy type, underlying land-use matters and development in already disturbed areas resulted in fewer total impacts; 2) the number and source of potential mortality varied between energy types, however, the lack of robust mortality data limits our ability to use this information to estimate and mitigate impacts; and 3) per unit energy produced, oil and gas extraction was less impactful on an annual basis but is likely to have a much larger cumulative footprint than wind energy over time. This rapid evaluation of landscape-scale energy development impacts could be replicated in other regions, and our specific findings can help meet the challenge of balancing land conservation with society's demand for energy.

  8. Drivers of Intensity and Prevalence of Flea Parasitism on Small Mammals in East African Savanna Ecosystems.

    PubMed

    Young, Hillary S; Dirzo, Rodolfo; McCauley, Douglas J; Agwanda, Bernard; Cattaneo, Lia; Dittmar, Katharina; Eckerlin, Ralph P; Fleischer, Robert C; Helgen, Lauren E; Hintz, Ashley; Montinieri, John; Zhao, Serena; Helgen, Kristofer M

    2015-06-01

    The relative importance of environmental factors and host factors in explaining variation in prevalence and intensity of flea parasitism in small mammal communities is poorly established. We examined these relationships in an East African savanna landscape, considering multiple host levels: across individuals within a local population, across populations within species, and across species within a landscape. We sampled fleas from 2,672 small mammals of 27 species. This included a total of 8,283 fleas, with 5 genera and 12 species identified. Across individual hosts within a site, both rodent body mass and season affected total intensity of flea infestation, although the explanatory power of these factors was generally modest (<10%). Across host populations in the landscape, we found consistently positive effects of host density and negative effects of vegetation cover on the intensity of flea infestation. Other factors explored (host diversity, annual rainfall, anthropogenic disturbance, and soil properties) tended to have lower and less consistent explanatory power. Across host species in the landscape, we found that host body mass was strongly positively correlated with both prevalence and intensity of flea parasitism, while average robustness of a host species to disturbance was not correlated with flea parasitism. Cumulatively, these results provide insight into the intricate roles of both host and environmental factors in explaining complex patterns of flea parasitism across landscape mosaics.

  9. Development on drought-stressed host plants affects life history, flight morphology and reproductive output relative to landscape structure.

    PubMed

    Gibbs, Melanie; Van Dyck, Hans; Breuker, Casper J

    2012-01-01

    With global climate change, rainfall is becoming more variable. Predicting the responses of species to changing rainfall levels is difficult because, for example in herbivorous species, these effects may be mediated indirectly through changes in host plant quality. Furthermore, species responses may result from a simultaneous interaction between rainfall levels and other environmental variables such as anthropogenic land use or habitat quality. In this eco-evolutionary study, we examined how male and female Pararge aegeria (L.) from woodland and agricultural landscape populations were affected by the development on drought-stressed host plants. Compared with individuals from woodland landscapes, when reared on drought-stressed plants agricultural individuals had longer development times, reduced survival rates and lower adult body masses. Across both landscape types, growth on drought-stressed plants resulted in males and females with low forewing aspect ratios and in females with lower wing loading and reduced fecundity. Development on drought-stressed plants also had a landscape-specific effect on reproductive output; agricultural females laid eggs that had a significantly lower hatching success. Overall, our results highlight several potential mechanisms by which low water availability, via changes in host plant quality, may differentially influence P. aegeria populations relative to landscape structure.

  10. Water economy of neotropical savanna trees: six paradigms revisited.

    Treesearch

    Guillermo Goldstein; Fredrick C. Meinzer; Sandra J. Bucci

    2008-01-01

    Biologists have long been puzzled by the striking morphological and anatomical characteristics of Neotropical savanna trees which have large scleromorphic leaves, allocate more than half of their total biomass to belowground structures and produce new leaves during the peak of the dry season. Based on results of ongoing interdisciplinary projects in the savannas of...

  11. Regional variations in biomass distribution in Brazilian savanna woodland

    Treesearch

    S.d.C. de Miranda; M. Bustamente; M. Palace; S. Hagen; M. Keller; L.G. Ferreira

    2014-01-01

    The Cerrado, the savanna biome in central Brazil, mostly comprised of woodland savanna, is experiencing intense and fast land use changes. To understand the changes in Cerrado carbon stocks, we present an overview of biomass distribution in different Cerrado vegetation types (i.e., grasslands, shrublands and forestlands). We surveyed 26 studies including 170 Cerrado...

  12. Development of new Dutch Elm disease-tolerant selections for restoration of the American Elm in urban and forested landscapes

    Treesearch

    C.C. Pinchot; C.E. Flower; K.S. Knight; C. Marks; R. Minocha; D. Lesser; K. Woeste; P.G. Schaberg; B. Baldwin; D.M. Delatte; T.D. Fox; N. Hayes-Plazolles; B. Held; K. Lehtoma; S. Long; S. Mattix; A. Sipes; J.M. Slavicek

    2017-01-01

    The goal of our research and development efforts is to restore American elm (Ulmus americana) as a species in both natural and urban landscapes. Accomplishing this goal requires identification/generation of additional American elm cultivars that are tolerant to Dutch elm disease (DED) caused by Ophiostoma ulmi and O. novo-ulmi, and development of methods to reintroduce...

  13. Anticipating Forest and Range Land Development in Central Oregon (USA) for Landscape Analysis, with an Example Application Involving Mule Deer

    NASA Astrophysics Data System (ADS)

    Kline, Jeffrey D.; Moses, Alissa; Burcsu, Theresa

    2010-05-01

    Forest policymakers, public lands managers, and scientists in the Pacific Northwest (USA) seek ways to evaluate the landscape-level effects of policies and management through the multidisciplinary development and application of spatially explicit methods and models. The Interagency Mapping and Analysis Project (IMAP) is an ongoing effort to generate landscape-wide vegetation data and models to evaluate the integrated effects of disturbances and management activities on natural resource conditions in Oregon and Washington (USA). In this initial analysis, we characterized the spatial distribution of forest and range land development in a four-county pilot study region in central Oregon. The empirical model describes the spatial distribution of buildings and new building construction as a function of population growth, existing development, topography, land-use zoning, and other factors. We used the model to create geographic information system maps of likely future development based on human population projections to inform complementary landscape analyses underway involving vegetation, habitat, and wildfire interactions. In an example application, we use the model and resulting maps to show the potential impacts of future forest and range land development on mule deer ( Odocoileus hemionus) winter range. Results indicate significant development encroachment and habitat loss already in 2000 with development located along key migration routes and increasing through the projection period to 2040. The example application illustrates a simple way for policymakers and public lands managers to combine existing data and preliminary model outputs to begin to consider the potential effects of development on future landscape conditions.

  14. Anticipating forest and range land development in central Oregon (USA) for landscape analysis, with an example application involving mule deer.

    PubMed

    Kline, Jeffrey D; Moses, Alissa; Burcsu, Theresa

    2010-05-01

    Forest policymakers, public lands managers, and scientists in the Pacific Northwest (USA) seek ways to evaluate the landscape-level effects of policies and management through the multidisciplinary development and application of spatially explicit methods and models. The Interagency Mapping and Analysis Project (IMAP) is an ongoing effort to generate landscape-wide vegetation data and models to evaluate the integrated effects of disturbances and management activities on natural resource conditions in Oregon and Washington (USA). In this initial analysis, we characterized the spatial distribution of forest and range land development in a four-county pilot study region in central Oregon. The empirical model describes the spatial distribution of buildings and new building construction as a function of population growth, existing development, topography, land-use zoning, and other factors. We used the model to create geographic information system maps of likely future development based on human population projections to inform complementary landscape analyses underway involving vegetation, habitat, and wildfire interactions. In an example application, we use the model and resulting maps to show the potential impacts of future forest and range land development on mule deer (Odocoileus hemionus) winter range. Results indicate significant development encroachment and habitat loss already in 2000 with development located along key migration routes and increasing through the projection period to 2040. The example application illustrates a simple way for policymakers and public lands managers to combine existing data and preliminary model outputs to begin to consider the potential effects of development on future landscape conditions.

  15. A model of late quaternary landscape development in the Delaware Valley, New Jersey and Pennsylvania

    USGS Publications Warehouse

    Ridge, J.C.; Evenson, E.B.; Sevon, W.D.

    1992-01-01

    In the Delaware Valley of New Jersey and eastern Pennsylvania the late Quaternary history of colluviation, fluvial adjustment, and soil formation is based on the ages of pre-Wisconsinan soils and glacial deposits which are indicated by feld relationships and inferred from mid-latitude climate changes indicated by marine oxygen-isotope records. The area is divided into four terranes characterized by sandstone, gneiss, slate and carbonate rocks. Since the last pre-Wisconsinan glaciation (> 130 ka, inferred to be late Illinoian), each terrane responded differently to chemical and mechanical weathering. During the Sangamon interglacial stage (??? 130-75 ka) in situ weathering is inferred to have occurred at rates greater than transportation of material which resulted in the formation of deep, highly weathered soil and saprolite, and dissolution of carbonate rocks. Cold climatic conditions during the Wisconsinan, on the other hand, induced erosion of the landscape at rates faster than soil development. Upland erosion during the Wisconsinan removed pre-Wisconsinan soil and glacial sediment and bedrock to produce muddy to blocky colluvium, gre??zes lite??es, and alluvial fans on footslopes. Fluvial gravel and overlying colluvium in the Delaware Valley, both buried by late Wisconsinan outwash, are inferred to represent episodes of early and middle Wisconsinan (??? 75-25 ka) upland erosion and river aggradiation followed by river degradation and colluvium deposition. Early-middle Wisconsinan colluvium is more voluminous than later colluvium despite colder, possibly permafrost conditions during the late Wisconsinan ??? 25-10 ka). Extensive colluviation during the early and middle Wisconsinan resulted from a longer (50 kyr), generally cold interval of erosion with a greater availability of easily eroded pre-Wisconsinan surficial materials on uplands than during the late Wisconsinan. After recession of late Wisconsinan ice from its terminal position, soil formation and

  16. Fire-free land use in pre-1492 Amazonian savannas.

    PubMed

    Iriarte, José; Power, Mitchell J; Rostain, Stéphen; Mayle, Francis E; Jones, Huw; Watling, Jennifer; Whitney, Bronwen S; McKey, Doyle B

    2012-04-24

    The nature and scale of pre-Columbian land use and the consequences of the 1492 "Columbian Encounter" (CE) on Amazonia are among the more debated topics in New World archaeology and paleoecology. However, pre-Columbian human impact in Amazonian savannas remains poorly understood. Most paleoecological studies have been conducted in neotropical forest contexts. Of studies done in Amazonian savannas, none has the temporal resolution needed to detect changes induced by either climate or humans before and after A.D. 1492, and only a few closely integrate paleoecological and archaeological data. We report a high-resolution 2,150-y paleoecological record from a French Guianan coastal savanna that forces reconsideration of how pre-Columbian savanna peoples practiced raised-field agriculture and how the CE impacted these societies and environments. Our combined pollen, phytolith, and charcoal analyses reveal unexpectedly low levels of biomass burning associated with pre-A.D. 1492 savanna raised-field agriculture and a sharp increase in fires following the arrival of Europeans. We show that pre-Columbian raised-field farmers limited burning to improve agricultural production, contrasting with extensive use of fire in pre-Columbian tropical forest and Central American savanna environments, as well as in present-day savannas. The charcoal record indicates that extensive fires in the seasonally flooded savannas of French Guiana are a post-Columbian phenomenon, postdating the collapse of indigenous populations. The discovery that pre-Columbian farmers practiced fire-free savanna management calls into question the widely held assumption that pre-Columbian Amazonian farmers pervasively used fire to manage and alter ecosystems and offers fresh perspectives on an emerging alternative approach to savanna land use and conservation that can help reduce carbon emissions.

  17. Fire-free land use in pre-1492 Amazonian savannas

    PubMed Central

    Iriarte, José; Power, Mitchell J.; Rostain, Stéphen; Mayle, Francis E.; Jones, Huw; Watling, Jennifer; Whitney, Bronwen S.; McKey, Doyle B.

    2012-01-01

    The nature and scale of pre-Columbian land use and the consequences of the 1492 “Columbian Encounter” (CE) on Amazonia are among the more debated topics in New World archaeology and paleoecology. However, pre-Columbian human impact in Amazonian savannas remains poorly understood. Most paleoecological studies have been conducted in neotropical forest contexts. Of studies done in Amazonian savannas, none has the temporal resolution needed to detect changes induced by either climate or humans before and after A.D. 1492, and only a few closely integrate paleoecological and archaeological data. We report a high-resolution 2,150-y paleoecological record from a French Guianan coastal savanna that forces reconsideration of how pre-Columbian savanna peoples practiced raised-field agriculture and how the CE impacted these societies and environments. Our combined pollen, phytolith, and charcoal analyses reveal unexpectedly low levels of biomass burning associated with pre-A.D. 1492 savanna raised-field agriculture and a sharp increase in fires following the arrival of Europeans. We show that pre-Columbian raised-field farmers limited burning to improve agricultural production, contrasting with extensive use of fire in pre-Columbian tropical forest and Central American savanna environments, as well as in present-day savannas. The charcoal record indicates that extensive fires in the seasonally flooded savannas of French Guiana are a post-Columbian phenomenon, postdating the collapse of indigenous populations. The discovery that pre-Columbian farmers practiced fire-free savanna management calls into question the widely held assumption that pre-Columbian Amazonian farmers pervasively used fire to manage and alter ecosystems and offers fresh perspectives on an emerging alternative approach to savanna land use and conservation that can help reduce carbon emissions. PMID:22493248

  18. Managing the matrix: decadal responses of eucalypt-dominated savanna to ambient fire regimes.

    PubMed

    Russell-Smith, Jeremy; Price, Owen F; Murphy, Brett P

    2010-09-01

    Much of our understanding of the response of savanna systems to fire disturbance relies on observations derived from manipulative fire plot studies. Equivocal findings from both recent Australian and African savanna fire plot assessments have significant implications for informing conservation management and reliable estimation of biomass stocks and dynamics. Influential northern Australian replicated fire plot studies include the 24-year plot-scale Munmarlary and the five-year catchment-scale Kapalga, mesic savanna (> 1000 mm/yr of rainfall) experiments in present-day Kakadu National Park. At Munmarlary, under low-to-moderate-intensity fire treatments, woody vegetation dominated by mature eucalypts was found to be structurally stable. At Kapalga, substantial declines in woody biomass were observed under more intense fire treatments, and modeling assessments implicate early-season fires as having adverse effects on longer-term tree recruitment. Given these contrasting perspectives, here we take advantage of a landscape-scale fire response monitoring program established on three major northern Australian conservation reserves (Kakadu, Litchfield, and Nitmiluk National Parks). Using statistical modeling we assess the decadal effects of ambient fire regime parameters (fire frequency, severity, seasonality, time since fire) on 32 vegetation structure components and abundance of 21 tree and 16 grass species from 122 monitoring plots. Over the study period the mean annual frequency of burning of plots was 0.53, comprising mostly early-dry-season, low-severity fires. Structural and species responses were variable but often substantial, notably resulting in stem recruitment and declines in juveniles, but only weakly explained by fire regime and habitat variables. Modeling of these observations under three realistic scenarios (increased fire severity under projected worsening climate change; modest and significant reductions in fire frequency to meet conservation criteria

  19. Modeling soil moisture memory in savanna ecosystems

    NASA Astrophysics Data System (ADS)

    Gou, S.; Miller, G. R.

    2011-12-01

    Antecedent soil conditions create an ecosystem's "memory" of past rainfall events. Such soil moisture memory effects may be observed over a range of timescales, from daily to yearly, and lead to feedbacks between hydrological and ecosystem processes. In this study, we modeled the soil moisture memory effect on savanna ecosystems in California, Arizona, and Africa, using a system dynamics model created to simulate the ecohydrological processes at the plot-scale. The model was carefully calibrated using soil moisture and evapotranspiration data collected at three study sites. The model was then used to simulate scenarios with various initial soil moisture conditions and antecedent precipitation regimes, in order to study the soil moisture memory effects on the evapotranspiration of understory and overstory species. Based on the model results, soil texture and antecedent precipitation regime impact the redistribution of water within soil layers, potentially causing deeper soil layers to influence the ecosystem for a longer time. Of all the study areas modeled, soil moisture memory of California savanna ecosystem site is replenished and dries out most rapidly. Thus soil moisture memory could not maintain the high rate evapotranspiration for more than a few days without incoming rainfall event. On the contrary, soil moisture memory of Arizona savanna ecosystem site lasts the longest time. The plants with different root depths respond to different memory effects; shallow-rooted species mainly respond to the soil moisture memory in the shallow soil. The growing season of grass is largely depended on the soil moisture memory of the top 25cm soil layer. Grass transpiration is sensitive to the antecedent precipitation events within daily to weekly timescale. Deep-rooted plants have different responses since these species can access to the deeper soil moisture memory with longer time duration Soil moisture memory does not have obvious impacts on the phenology of woody plants

  20. Trade-offs between biodiversity conservation and economic development in five tropical forest landscapes.

    PubMed

    Sandker, Marieke; Ruiz-Perez, Manuel; Campbell, Bruce M

    2012-10-01

    This study explores how conservation and development are interlinked and quantifies their reciprocal trade-offs. It identifies interventions which hold a promise to improve both conservation and development outcomes. The study finds that development trajectories can either be at the cost of conservation or can benefit conservation, but in all cases sustained poverty negatively affects conservation in the long term. Most scenarios with better outcomes for conservation come at a cost for development and the financial benefits of payments for environmental services (PES) are not sufficient to compensate for lost opportunities to earn cash. However, implementation of strategies for reducing emissions from deforestation and forest degradation in locations with low population densities come close to overcoming opportunity costs. Environmental services and subsistence income enhance the attractiveness of conservation scenarios to local people and in situations where these benefits are obvious, PES may provide the extra cash incentive to tip the balance in favor of such a scenario. The paper stresses the importance of external factors (such as industrial investments and the development of the national economy) in determining landscape scale outcomes, and suggests a negotiating and visioning role for conservation agencies.

  1. Trade-Offs Between Biodiversity Conservation and Economic Development in Five Tropical Forest Landscapes

    NASA Astrophysics Data System (ADS)

    Sandker, Marieke; Ruiz-Perez, Manuel; Campbell, Bruce M.

    2012-10-01

    This study explores how conservation and development are interlinked and quantifies their reciprocal trade-offs. It identifies interventions which hold a promise to improve both conservation and development outcomes. The study finds that development trajectories can either be at the cost of conservation or can benefit conservation, but in all cases sustained poverty negatively affects conservation in the long term. Most scenarios with better outcomes for conservation come at a cost for development and the financial benefits of payments for environmental services (PES) are not sufficient to compensate for lost opportunities to earn cash. However, implementation of strategies for reducing emissions from deforestation and forest degradation in locations with low population densities come close to overcoming opportunity costs. Environmental services and subsistence income enhance the attractiveness of conservation scenarios to local people and in situations where these benefits are obvious, PES may provide the extra cash incentive to tip the balance in favor of such a scenario. The paper stresses the importance of external factors (such as industrial investments and the development of the national economy) in determining landscape scale outcomes, and suggests a negotiating and visioning role for conservation agencies.

  2. Nitrous oxide emissions from agricultural landscapes: quantification tools, policy development, and opportunities for improved management

    NASA Astrophysics Data System (ADS)

    Tonitto, C.; Gurwick, N. P.

    2012-12-01

    Policy initiatives to reduce greenhouse gas emissions (GHG) have promoted the development of agricultural management protocols to increase SOC storage and reduce GHG emissions. We review approaches for quantifying N2O flux from agricultural landscapes. We summarize the temporal and spatial extent of observations across representative soil classes, climate zones, cropping systems, and management scenarios. We review applications of simulation and empirical modeling approaches and compare validation outcomes across modeling tools. Subsequently, we review current model application in agricultural management protocols. In particular, we compare approaches adapted for compliance with the California Global Warming Solutions Act, the Alberta Climate Change and Emissions Management Act, and by the American Carbon Registry. In the absence of regional data to drive model development, policies that require GHG quantification often use simple empirical models based on highly aggregated data of N2O flux as a function of applied N - Tier 1 models according to IPCC categorization. As participants in development of protocols that could be used in carbon offset markets, we observed that stakeholders outside of the biogeochemistry community favored outcomes from simulation modeling (Tier 3) rather than empirical modeling (Tier 2). In contrast, scientific advisors were more accepting of outcomes based on statistical approaches that rely on local observations, and their views sometimes swayed policy practitioners over the course of policy development. Both Tier 2 and Tier 3 approaches have been implemented in current policy development, and it is important that the strengths and limitations of both approaches, in the face of available data, be well-understood by those drafting and adopting policies and protocols. The reliability of all models is contingent on sufficient observations for model development and validation. Simulation models applied without site-calibration generally

  3. Modeling the epigenetic attractors landscape: toward a post-genomic mechanistic understanding of development

    PubMed Central

    Davila-Velderrain, Jose; Martinez-Garcia, Juan C.; Alvarez-Buylla, Elena R.

    2015-01-01

    Robust temporal and spatial patterns of cell types emerge in the course of normal development in multicellular organisms. The onset of degenerative diseases may result from altered cell fate decisions that give rise to pathological phenotypes. Complex networks of genetic and non-genetic components underlie such normal and altered morphogenetic patterns. Here we focus on the networks of regulatory interactions involved in cell-fate decisions. Such networks modeled as dynamical non-linear systems attain particular stable configurations on gene activity that have been interpreted as cell-fate states. The network structure also restricts the most probable transition patterns among such states. The so-called Epigenetic Landscape (EL), originally proposed by C. H. Waddington, was an early attempt to conceptually explain the emergence of developmental choices as the result of intrinsic constraints (regulatory interactions) shaped during evolution. Thanks to the wealth of molecular genetic and genomic studies, we are now able to postulate gene regulatory networks (GRN) grounded on experimental data, and to derive EL models for specific cases. This, in turn, has motivated several mathematical and computational modeling approaches inspired by the EL concept, that may be useful tools to understand and predict cell-fate decisions and emerging patterns. In order to distinguish between the classical metaphorical EL proposal of Waddington, we refer to the Epigenetic Attractors Landscape (EAL), a proposal that is formally framed in the context of GRNs and dynamical systems theory. In this review we discuss recent EAL modeling strategies, their conceptual basis and their application in studying the emergence of both normal and pathological developmental processes. In addition, we discuss how model predictions can shed light into rational strategies for cell fate regulation, and we point to challenges ahead. PMID:25954305

  4. Modeling the epigenetic attractors landscape: toward a post-genomic mechanistic understanding of development.

    PubMed

    Davila-Velderrain, Jose; Martinez-Garcia, Juan C; Alvarez-Buylla, Elena R

    2015-01-01

    Robust temporal and spatial patterns of cell types emerge in the course of normal development in multicellular organisms. The onset of degenerative diseases may result from altered cell fate decisions that give rise to pathological phenotypes. Complex networks of genetic and non-genetic components underlie such normal and altered morphogenetic patterns. Here we focus on the networks of regulatory interactions involved in cell-fate decisions. Such networks modeled as dynamical non-linear systems attain particular stable configurations on gene activity that have been interpreted as cell-fate states. The network structure also restricts the most probable transition patterns among such states. The so-called Epigenetic Landscape (EL), originally proposed by C. H. Waddington, was an early attempt to conceptually explain the emergence of developmental choices as the result of intrinsic constraints (regulatory interactions) shaped during evolution. Thanks to the wealth of molecular genetic and genomic studies, we are now able to postulate gene regulatory networks (GRN) grounded on experimental data, and to derive EL models for specific cases. This, in turn, has motivated several mathematical and computational modeling approaches inspired by the EL concept, that may be useful tools to understand and predict cell-fate decisions and emerging patterns. In order to distinguish between the classical metaphorical EL proposal of Waddington, we refer to the Epigenetic Attractors Landscape (EAL), a proposal that is formally framed in the context of GRNs and dynamical systems theory. In this review we discuss recent EAL modeling strategies, their conceptual basis and their application in studying the emergence of both normal and pathological developmental processes. In addition, we discuss how model predictions can shed light into rational strategies for cell fate regulation, and we point to challenges ahead.

  5. Re-evaluating functional landscape of the cardiovascular system during development.

    PubMed

    Takada, Norio; Omae, Madoka; Sagawa, Fumihiko; Chi, Neil C; Endo, Satsuki; Kozawa, Satoshi; Sato, Thomas N

    2017-10-05

    The cardiovascular system facilitates body-wide distribution of oxygen, a vital process for development and survival of virtually all vertebrates. However, zebrafish, a vertebrate model organism, appears to form organs and survive mid-larval periods without the functional cardiovascular system. Despite such dispensability, it is the first organ to develop. Such enigma prompted us to hypothesize yet other cardiovascular functions that are important for developmental and/or physiological processes. Hence, systematic cellular ablations and functional perturbations are performed on zebrafish cardiovascular system to gain comprehensive and body-wide understanding of such functions and to elucidate underlying mechanisms. This approach identifies a set of organ-specific genes, each implicated for important functions. The study also unveils distinct cardiovascular mechanisms, each differentially regulating their expressions in organ-specific and oxygen-independent manners. Such mechanisms are mediated by organ-vessel interactions, circulation-dependent signals, and circulation-independent beating-heart-derived signals. Hence, a comprehensive and body-wide functional landscape of the cardiovascular system reported herein may provide a clue as to why it is the first organ to develop. Furthermore, the dataset herein could serve as a resource for the study of organ development and function. © 2017. Published by The Company of Biologists Ltd.

  6. Mitigating the effects of landscape development on streams in urbanizing watersheds

    USGS Publications Warehouse

    Hogan, Dianna M.; Jarnagin, S. Taylor; Loperfido, John V.; Van Ness, Keith

    2013-01-01

    This collaborative study examined urbanization and impacts on area streams while using the best available sediment and erosion control (S&EC) practices in developing watersheds in Maryland, United States. During conversion of the agricultural and forested watersheds to urban land use, land surface topography was graded and vegetation was removed creating a high potential for sediment generation and release during storm events. The currently best available S&EC facilities were used during the development process to mitigate storm runoff water quality, quantity, and timing before entering area streams. Detailed Geographic Information System (GIS) maps were created to visualize changing land use and S&EC practices, five temporal collections of LiDAR (light detection and ranging) imagery were used to map the changing landscape topography, and streamflow, physical geomorphology, and habitat data were used to assess the ability of the S&EC facilities to protect receiving streams during development. Despite the use of the best available S&EC facilities, receiving streams experienced altered flow, geomorphology, and decreased biotic community health. These impacts on small streams during watershed development affect sediment and nutrient loads to larger downstream aquatic ecosystems such as the Chesapeake Bay.

  7. Long-term development of the Czech landscape studied on the basis of old topographic maps

    NASA Astrophysics Data System (ADS)

    Skokanová, H.; Havlíček, M.

    2009-04-01

    The paper deals with long-term land use changes in the Czech Republic with the help of old topographic maps. Departments of Landscape Ecology and GIS Applications from the Silva Tarouca Research Institute for Landscape and Ornamental Gardening, v.v.i. study these changes mainly in the research project MSM 6293359101 Research into sources and indicators of biodiversity in cultural landscape in the context of its fragmentation dynamics, the subpart Quantitative analysis of the dynamics of the Czech landscape development. In this paper, the authors concentrate mainly on map sources, which were acquired for the purpose of the project and also introduce partial results. Maps, which are the sources for the analyses, are following: maps from 2nd Austrian military survey in the scale 1:28 800 (created for the territory of the Czech Republic in the period 1836-1852), maps from 3rd Austrian military survey in the scale 1:25 000 (created for the Czech Republic in the period 1876-1880), Czechoslovak military topographic maps in the scale 1:25 000 from 1950s and 1990s, and Czech topographic base maps in the scale 1:10 000 from 2002-2006. It is necessary to complete maps of the 2nd and 3rd Austrian military survey thanks to their incompleteness, mainly along state borders. Also maps from 1nd Austrian military survey in the scale 1:28 800 (created for the Czech Republic in the period 1764-1783) are available; however, their usage for the accurate analyses in the GIS environment is restricted by their poor cartographic accuracy. Apart of the above mentioned maps, there has been progress in collecting maps from the interwar and war period (revised maps of the 3rd Austrian military survey maps, maps of the provisional military survey from 1923-1933, maps of definitive military survey from 1934-1938 and maps from survey of Moravian part of the Protectorate of Bohemia and Moravia, so called Messtischblätter from 1939-1945). Maps from five periods are manually vectorised in the GIS

  8. Governing Portable Conservation and Development Landscapes: Reconsidering Evidence in the Context of the Mbaracayú Biosphere Reserve

    ERIC Educational Resources Information Center

    Elgert, Laureen

    2014-01-01

    Conservation-with-development landscapes, such as UNESCO's Man and Biosphere Reserves, differentiate between areas of "nature" and "society". In Paraguay's Mbaracayú Biosphere Reserve, as elsewhere, this model has been used to support governance that focuses on conservation in the "core area" and sustainable…

  9. Developing and testing a landscape habitat suitability model for fisher (Martes pennanti) in forests of interior northern California

    Treesearch

    W.J. Zielinski; J. R. Dunk; J. S. Yaeger; D. W. LaPlante

    2010-01-01

    The fisher is warranted for protection under the Endangered Species Act in the western United States and, as such, it is especially important that conservation and management actions are based on sound scientific information. We developed a landscape-scale suitability model for interior northern California to predict the probability of detecting fishers and to identify...

  10. Chapter 1: A Framework for the Development and Application of INLAS: the Interior Northwest Landscape Analysis System

    Treesearch

    R. James Barbour; Alan A. Ager; Jane L. Hayes

    2004-01-01

    The Interior Northwest Landscape Analysis System is a partnership among researchers and natural resource managers from both the public and private sectors. The project is an effort to increase our understanding of the role of vegetative succession, natural disturbance, and management actions at the watershed scale. The effort will advance the development and...

  11. Developing and testing a landscape habitat suitability model for the American marten (Martes americana) in the Cascades mountains of California

    Treesearch

    Thomas A. Kirk; William J. Zielinski

    2009-01-01

    We used field surveys and Geographic Information System data to identify landscape-scale habitat associations of American martens (Martes americana) and to develop a model to predict their occurrence in northeastern California. Systematic surveys using primarily enclosed track plates, with 10-km spacing, were conducted across a 27,700 km

  12. Evaluating governance for sustainable development - Insights from experiences in the Dutch fen landscape.

    PubMed

    den Uyl, Roos M; Driessen, Peter P J

    2015-11-01

    Prominent strands of discussion in the literature on governance for sustainable development debate how change can be induced to enhance sustainability, and how to evaluate the interventions aimed at prompting such change. Strikingly, there are few contributions about how prominent ideas of inducing change deal with multiple governance criteria for pursuing sustainable development. Moreover, the way ideas about inducing change relate to criteria of governance for sustainable development is not yet studied in an empirical context. This paper therefore comparatively analyses how three prominent modes of sustainable development governance - adaptive management, transition management and payments for environmental services - relate to a set of five prominent criteria reported in the literature, namely: equity, democracy, legitimacy, the handling of scale issues and the handling of uncertainty issues. It finds that the academic debates on these three modes address these criteria with varying attention and rather fragmented, while in the empirical setting of the Dutch fen landscape several aspects relating to the studied criteria were present and substantially influenced the functioning of the three modes of sustainable development. Together, the analysis of the literature debate and the empirical data are able to show that a narrow evaluation perspective may fail to diagnose and capture relevant struggles and complexities coming along with governance for sustainable development relevant issues. The study shows that in order to advance our understanding of governance for sustainable development, it is indeed important to include multiple criteria in studying these modes. Moreover, the study shows the importance of including empirical experiences which manifest when different modes for sustainable development are applied in real-world settings.

  13. Do "savanna" chimpanzees consume C4 resources?

    PubMed

    Sponheimer, M; Loudon, J E; Codron, D; Howells, M E; Pruetz, J D; Codron, J; de Ruiter, D J; Lee-Thorp, J A

    2006-08-01

    Several stable carbon isotopic studies have shown that South African australopiths consumed significant quantities of C(4) resources (tropical grasses, sedges, or animals that eat those foods), but relatively little is known about the consumption of such resources by chimpanzees. Here, we present stable carbon isotopic data for 36 chimpanzee hair samples from Fongoli, one of the driest and most open areas inhabited by chimpanzees. These data suggest that the Fongoli chimpanzees consume little in the way of C(4) vegetation or animals that eat such vegetation, even though these resources are locally abundant and preferred fruits are more widely scattered than at most chimpanzee study sites. The homogeneity of the Fongoli results is especially striking and recalls the narrow isotopic distribution of stenotopic savanna mammals. This is in stark contrast to what has been observed for australopiths, which had highly variable diets and consumed about 35% C(4) vegetation on average. Carbon isotope data for modern and fossil Papio depict a dietarily variable genus with a tendency to consume C(4) vegetation. This trophic flexibility, or willingness to consume C(4) savanna resources, may make Papio a more profitable ecological analog for australopiths than chimpanzees.

  14. Termites facilitate and ungulates limit savanna tree regeneration.

    PubMed

    Støen, Ole-Gunnar; Okullo, Paul; Eid, Tron; Moe, Stein R

    2013-08-01

    Both large herbivores and termites are key functional groups in savanna ecosystems, and in many savanna areas, large termite mounds (termitaria) are associated with distinct woody clusters. Studies on the effect of large mammals on tree regeneration are few, and the results are conflicting. Large herbivores have been found to be important seedling predators in some areas, but facilitate tree regeneration by outcompeting small mammals and reducing grass cover in other areas. Through the use of the experimental fencing of termite mounds and adjacent savanna areas in this study, we investigated how termites and large herbivores influence tree regeneration. Termite mounds had a higher number of seedlings, more species richness, more alpha diversity (OD) and lower evenness (E) than savanna plots. Large herbivores did not significantly affect overall seedling density, species richness, OD or E. Beta diversity was higher in savanna areas than on termitaria, and beta diversity decreased in savanna areas when herbivores were excluded. Herbivore exclusion increased the density of the 12 (40%) most common seedling species, representing 79% of all seedlings, and fenced plots had relatively taller seedlings than open plots. Thus, termites were the main determinants of tree regeneration in our study area, but large mammals regulated the most common species. Although our study confirms previous work suggesting that large herbivores affect tree regeneration, we found that termites were an even more important determinant. Termite impacts on tree regeneration deserve increased attention by savanna ecologists.

  15. Expert-based versus habitat-suitability models to develop resistance surfaces in landscape genetics.

    PubMed

    Milanesi, Pietro; Holderegger, R; Caniglia, R; Fabbri, E; Galaverni, M; Randi, E

    2017-01-01

    Landscape genetics aims to investigate functional connectivity among wild populations by evaluating the impact of landscape features on gene flow. Genetic distances among populations or individuals are generally better explained by least-cost path (LCP) distances derived from resistance surfaces than by simple Euclidean distances. Resistance surfaces reflect the cost for an organism to move through particular landscape elements. However, determining the effects of landscape types on movements is challenging. Because of a general lack of empirical data on movements, resistance surfaces mostly rely on expert knowledge. Habitat-suitability models potentially provide a more objective method to estimate resistance surfaces than expert opinions, but they have rarely been applied in landscape genetics so far. We compared LCP distances based on expert knowledge with LCP distances derived from habitat-suitability models to evaluate their performance in landscape genetics. We related all LCP distances to genetic distances in linear mixed effect models on an empirical data set of wolves (Canis lupus) from Italy. All LCP distances showed highly significant (P ≤ 0.0001) standardized β coefficients and R (2) values, but LCPs from habitat-suitability models generally showed higher values than those resulting from expert knowledge. Moreover, all LCP distances better explained genetic distances than Euclidean distances, irrespective of the approaches used. Considering our results, we encourage researchers in landscape genetics to use resistance surfaces based on habitat suitability which performed better than expert-based LCPs in explaining patterns of gene flow and functional connectivity.

  16. The influence of landscape features on road development in a loess region, China.

    PubMed

    Bi, Xiaoli; Wang, Hui; Zhou, Rui

    2011-10-01

    Many ecologists focus on the effects of roads on landscapes, yet few consider how landscapes affect road systems. In this study, therefore, we quantitatively evaluated how land cover, topography, and building density affected the length density, node density, spatial pattern, and location of roads in Dongzhi Yuan, a typical loess region in China. Landscape factors and roads were mapped using images from SPOT satellite (Système Probatoire d'Observation de la Terre), initiated by the French space agency and a digital elevation model (DEM). Detrended canonical correspondence analysis (DCCA), a useful ordination technique to explain species-environment relations in community ecology, was applied to evaluate the ways in which landscapes may influence roads. The results showed that both farmland area and building density were positively correlated with road variables, whereas gully density and the coefficient of variation (CV of DEM) showed negative correlations. The CV of DEM, farmland area, grassland area, and building density explained variation in node density, length density, and the spatial pattern of roads, whereas gully density and building density explained variation in variables representing road location. In addition, node density, rather than length density, was the primary road variable affected by landscape variables. The results showed that the DCCA was effective in explaining road-landscape relations. Understanding these relations can provide information for landscape managers and transportation planners.

  17. The Influence of Landscape Features on Road Development in a Loess Region, China

    NASA Astrophysics Data System (ADS)

    Bi, Xiaoli; Wang, Hui; Zhou, Rui

    2011-10-01

    Many ecologists focus on the effects of roads on landscapes, yet few consider how landscapes affect road systems. In this study, therefore, we quantitatively evaluated how land cover, topography, and building density affected the length density, node density, spatial pattern, and location of roads in Dongzhi Yuan, a typical loess region in China. Landscape factors and roads were mapped using images from SPOT satellite (Système Probatoire d'Observation de la Terre), initiated by the French space agency and a digital elevation model (DEM). Detrended canonical correspondence analysis (DCCA), a useful ordination technique to explain species-environment relations in community ecology, was applied to evaluate the ways in which landscapes may influence roads. The results showed that both farmland area and building density were positively correlated with road variables, whereas gully density and the coefficient of variation (CV of DEM) showed negative correlations. The CV of DEM, farmland area, grassland area, and building density explained variation in node density, length density, and the spatial pattern of roads, whereas gully density and building density explained variation in variables representing road location. In addition, node density, rather than length density, was the primary road variable affected by landscape variables. The results showed that the DCCA was effective in explaining road-landscape relations. Understanding these relations can provide information for landscape managers and transportation planners.

  18. Threshold Responses of Forest Birds to Landscape Changes around Exurban Development

    PubMed Central

    Suarez-Rubio, Marcela; Wilson, Scott; Leimgruber, Peter; Lookingbill, Todd

    2013-01-01

    Low-density residential development (i.e., exurban development) is often embedded within a matrix of protected areas and natural amenities, raising concern about its ecological consequences. Forest-dependent species are particularly susceptible to human settlement even at low housing densities typical of exurban areas. However, few studies have examined the response of forest birds to this increasingly common form of land conversion. The aim of this study was to assess whether, how, and at what scale forest birds respond to changes in habitat due to exurban growth. We evaluated changes in habitat composition (amount) and configuration (arrangement) for forest and forest-edge species around North America Breeding Bird Survey (BBS) stops between 1986 and 2009. We used Threshold Indicator Taxa Analysis to detect change points in species occurrence at two spatial extents (400-m and 1-km radius buffer). Our results show that exurban development reduced forest cover and increased habitat fragmentation around BBS stops. Forest birds responded nonlinearly to most measures of habitat loss and fragmentation at both the local and landscape extents. However, the strength and even direction of the response changed with the extent for several of the metrics. The majority of forest birds’ responses could be predicted by their habitat preferences indicating that management practices in exurban areas might target the maintenance of forested habitats, for example through easements or more focused management for birds within existing or new protected areas. PMID:23826325

  19. Revealing the pace of river landscape evolution during the Quaternary: recent developments in numerical dating methods

    NASA Astrophysics Data System (ADS)

    Rixhon, Gilles; Briant, Rebecca M.; Cordier, Stéphane; Duval, Mathieu; Jones, Anna; Scholz, Denis

    2017-06-01

    During the last twenty years, several technical developments have considerably intensified the use of numerical dating methods for the Quaternary. The study of fluvial archives has greatly benefited from these enhancements, opening new dating horizons for a range of archives at distinct time scales and thereby providing new insights into previously unanswered questions. In this contribution, we separately present the state of the art of five numerical dating methods that are frequently used in the fluvial context: radiocarbon, Luminescence, Electron Spin Resonance (ESR), 230Th/U and terrestrial cosmogenic nuclides (TCN) dating. We focus on the major recent developments for each technique that are most relevant for new dating applications in diverse fluvial environments and on explaining these for non-specialists. Therefore, essential information and precautions about sampling strategies in the field and/or laboratory procedures are provided. For each method, new and important implications for chronological reconstructions of Quaternary fluvial landscapes are discussed and, where necessary, exemplified by key case studies. A clear statement of the current technical limitations of these methods is included and forthcoming developments, which might possibly open new horizons for dating fluvial archives in the near future, are summarised.

  20. Change in the forested and developed landscape of the Lake Tahoe basin, California and Nevada, USA, 1940-2002

    USGS Publications Warehouse

    Raumann, C.G.; Cablk, Mary E.

    2008-01-01

    The current ecological state of the Lake Tahoe basin has been shaped by significant landscape-altering human activity and management practices since the mid-1850s; first through widespread timber harvesting from the 1850s to 1920s followed by urban development from the 1950s to the present. Consequences of landscape change, both from development and forest management practices including fire suppression, have prompted rising levels of concern for the ecological integrity of the region. The impacts from these activities include decreased water quality, degraded biotic communities, and increased fire hazard. To establish an understanding of the Lake Tahoe basin's landscape change in the context of forest management and development we mapped, quantified, and described the spatial and temporal distribution and variability of historical changes in land use and land cover in the southern Lake Tahoe basin (279 km2) from 1940 to 2002. Our assessment relied on post-classification change detection of multi-temporal land-use/cover and impervious-surface-area data that were derived through manual interpretation, image processing, and GIS data integration for four dates of imagery: 1940, 1969, 1987, and 2002. The most significant land conversion during the 62-year study period was an increase in developed lands with a corresponding decrease in forests, wetlands, and shrublands. Forest stand densities increased throughout the 62-year study period, and modern thinning efforts resulted in localized stand density decreases in the latter part of the study period. Additionally forests were gained from succession, and towards the end of the study period extensive tree mortality occurred. The highest rates of change occurred between 1940 and 1969, corresponding with dramatic development, then rates declined through 2002 for all observed landscape changes except forest density decrease and tree mortality. Causes of landscape change included regional population growth, tourism demands

  1. Savanna vegetation-fire-climate relationships differ among continents.

    PubMed

    Lehmann, Caroline E R; Anderson, T Michael; Sankaran, Mahesh; Higgins, Steven I; Archibald, Sally; Hoffmann, William A; Hanan, Niall P; Williams, Richard J; Fensham, Roderick J; Felfili, Jeanine; Hutley, Lindsay B; Ratnam, Jayashree; San Jose, Jose; Montes, Ruben; Franklin, Don; Russell-Smith, Jeremy; Ryan, Casey M; Durigan, Giselda; Hiernaux, Pierre; Haidar, Ricardo; Bowman, David M J S; Bond, William J

    2014-01-31

    Ecologists have long sought to understand the factors controlling the structure of savanna vegetation. Using data from 2154 sites in savannas across Africa, Australia, and South America, we found that increasing moisture availability drives increases in fire and tree basal area, whereas fire reduces tree basal area. However, among continents, the magnitude of these effects varied substantially, so that a single model cannot adequately represent savanna woody biomass across these regions. Historical and environmental differences drive the regional variation in the functional relationships between woody vegetation, fire, and climate. These same differences will determine the regional responses of vegetation to future climates, with implications for global carbon stocks.

  2. Unveiling changes in the landscape of patient populations in cancer early drug development.

    PubMed

    Hierro, Cinta; Azaro, Analía; Argilés, Guillem; Elez, Elena; Gómez, Patricia; Carles, Joan; Rodon, Jordi

    2016-11-09

    The introduction of new Molecularly Targeted Agents (MTA) has changed the landscape in Early Drug Development (EDD) over the last two decades, leading to an improvement in clinical trial design. Previous Phase 1 (Ph1) studies with cytotoxics focused on safety objectives, only recruiting heavily pre-treated cancer patients, have been left behind. In this review, we will illustrate the slow although unstoppable change that has increasingly been observed in those populations candidate to participate in EDD trials with the advent of MTA. As more evidence regarding oncogene addiction becomes available, molecular-biomarker driven selection has been implemented among Molecularly-Selected Population (MSP) studies. New Window-Of-Opportunity (WOO) and Phase 0 (Ph0) studies have been developed in order to assess whether a MTA produces the hypothetical proposed biological effect. The rising need of getting early pharmacokinetics and pharmacodynamics data has led to the conduction of Healthy Volunteer (HV) studies, in part favoured for the particular and different toxicity profile of these MTA. However, several challenges will need to be addressed in order to boost the implementation of these new clinical trial designs in the forthcoming years. Among the problems to overcome, we would highlight a better coordination effort between centers for ensuring adequate patient accrual among small patient populations and a deepening into the ethics implied in enrolling patients in studies with no therapeutic intent. However, these tribulations will be certainly compensated by the possibility of opening a new horizon of treatment for diseases with dismal prognosis.

  3. Development of a landscape unit delineation framework for ecoy-hydrologic models

    USDA-ARS?s Scientific Manuscript database

    A spatially distributed representation of basin hydrology and transport processes in eco-hydrological models facilitates the identification of critical source areas and the placement of management and conservation measures. Especially floodplains are critical landscape features that differ from nei...

  4. Forest ecosystem development in post-mining landscapes: a case study of the Lusatian lignite district

    NASA Astrophysics Data System (ADS)

    Hüttl, Reinhard F.; Weber, Edwin

    2001-08-01

    The restoration of surface mining landscapes requires the (re)creation of ecosystems. In Lusatia (eastern Germany), large-scale open-cast lignite mining operations generated spoil dumps widely consisting of acidified, phytotoxic substrates. Amelioration and rehabilitation measures have been developed and applied to these substrates since the 1950s. However, it is still not clear whether these approaches are sustainable. This paper reports on collaborative research work into the ecological potential of forest ecosystem development on typical minesites in the Lusatian lignite district. At first sight, pine stands on minesites along a chronosequence comprising about 35 years did not show differences when compared with stands on non-mined sites of the general region. Furthermore, with some modification, conceptual models for flora and fauna succession in forest stands on non-mined sites seem to be applicable, at least for the early stages of forest ecosystem development. For example, soil organism abundance and activity at minesites had already reached levels typical of non-mined sites after about 20-30 years. In contrast, mine soils are very different from non-mined soils of the test region. Chemically, mine soil development is dominated by processes originating from pyrite oxidation. Geogenic, i.e. lignitic, soil organic carbon was shown to substitute for some functions of pedogenic soil organic matter. Rooting was hampered but not completely impeded in strongly acidified soil compartments. Roots and mycorrhizae are apparently able to make use of the characteristic heterogeneity of young mine soils. Considering these recent results and the knowledge accumulated during more than 30 years of research on minesite rehabilitation internationally, it can be stated that minesite restoration might be used as an ideal case study for forest ecosystem development starting at "point zero" on " terra nova".

  5. Assessing the Impact of Landscape Development on Ecosystem Services Value in Tropical Watershed

    NASA Astrophysics Data System (ADS)

    Foo, Y. S.; Hashim, M.

    2014-02-01

    As development increases with demand, more forest lands are replaced with cropland, commercial plantation, and infrastructures for being able to accommodate the excessive growth in world's population. Environments were destroyed without considering their values in sustaining life on Earth.This phenomenon is still an ongoing scenario in most of the developing countries in the tropical region including Malaysia. Such unrestricted conversion may cause food or water crisis along with irreparable consequences to local and regional climate as the natural ecosystem is not only the main resources generator but also the climate stabilizer. Contrary to this, a study was conducted in Pahang Watershed, the largest watershed in Peninsular Malaysia with forest as the dominant land cover, to investigate the effect of landscape development on the ecosystem in terms of the erosion and ecosystem service value. Results of soil loss based on USLE indicated a direct relationship between development and total soil loss where total annual soil loss in year 2005 and 2010 showed a significant increase compare to year 2000. Meanwhile, developed and agricultural lands were discovered to be the main contributor whereas forest land produce the least soil loss (<10ton/ ha/yr). Apart from this, this study also reports a degrading trend in the overall ecological service value and goods (ESVG). Although oil palm had become the main commercial plantation in current years, the commercial profit brought by oil palm still insufficient to cover losses referring to overall estimated ESVG due to the forest clearance and soil degradation. In addition, for a destroyed ecosystem to be equilibrium again requires years. Therefore, ESVG of the tropical forest are expected to increase continuously in future which mean that the roles of the forest in conserving the environment stabilization and sustainability of life are getting more critical.

  6. From the Field to the Classroom: A Web-Based Teaching Tool on Depositional Environments and Landscape Development

    NASA Astrophysics Data System (ADS)

    Krzic, M.; Watson, K.; Grand, S.; Crowley, C.; Dyanatkar, S.; Bomke, A.; Smith, S.

    2012-04-01

    The relationship between sedimentary deposits, landforms and soil profile development is difficult for students to grasp in a conventional classroom setting. The ideal way to solve this is to take the students on extended field trips; however, field trips are expensive, have to be conducted during specific time periods, and can only handle a limited number of students. The objective of this project was to bring the field to the classroom via a virtual, dynamic web-based teaching tool illustrating common depositional environments and associated landforms and soils. The teaching tool was largely based on video footage obtained in the Canadian Rocky Mountains and in the grasslands of the southern interior of British Columbia. The Canadian Rockies are undergoing rapid deglaciation and provided excellent examples of new glacial deposits and early landscape development processes. On the other hand, British Columbia's grasslands became ice-free about 10,000 years ago and were used to illustrate landscape evolution and post-glaciation soil profile development. To bring these two environments together, video footage of corresponding landforms was shot at both locations and edited into a series of short video clips illustrating the link between depositional processes, resulting landforms and soils and their post-glacial evolution. Soil scientists, survey specialists and geomorphologists provided live commentary. The teaching tool (http://soilweb.landfood.ubc.ca/landscape/) is an open-access website merging video clips, sound recordings, text, photos and graphics intended to help students situate landforms within their geomorphologic context. This online teaching resource allows students to observe, on their own time, conditions under which sediments are deposited and soils are formed, and to witness the transformation of a barren, glacial landscape into a vegetated soil landscape. The tool can be used in various geomorphology, soil, agriculture, forestry, and natural

  7. Evaluation of multi-level social learning for sustainable landscapes: perspective of a development initiative in Bergslagen, Sweden.

    PubMed

    Axelsson, Robert; Angelstam, Per; Myhrman, Lennart; Sädbom, Stefan; Ivarsson, Milis; Elbakidze, Marine; Andersson, Kenneth; Cupa, Petr; Diry, Christian; Doyon, Frederic; Drotz, Marcus K; Hjorth, Arne; Hermansson, Jan Olof; Kullberg, Thomas; Lickers, F Henry; McTaggart, Johanna; Olsson, Anders; Pautov, Yurij; Svensson, Lennart; Törnblom, Johan

    2013-03-01

    To implement policies about sustainable landscapes and rural development necessitates social learning about states and trends of sustainability indicators, norms that define sustainability, and adaptive multi-level governance. We evaluate the extent to which social learning at multiple governance levels for sustainable landscapes occur in 18 local development initiatives in the network of Sustainable Bergslagen in Sweden. We mapped activities over time, and interviewed key actors in the network about social learning. While activities resulted in exchange of experiences and some local solutions, a major challenge was to secure systematic social learning and make new knowledge explicit at multiple levels. None of the development initiatives used a systematic approach to secure social learning, and sustainability assessments were not made systematically. We discuss how social learning can be improved, and how a learning network of development initiatives could be realized.

  8. Developing strategies to initialize landscape-scale vegetation maps from FIA data to enhance resolution of individual species-size cohort representation in the landscape disturbance model SIMPPLLE

    Treesearch

    Jacob John Muller

    2014-01-01

    The ability of forest resource managers to understand and anticipate landscape-scale change in composition and structure relies upon an adequate characterization of the current forest composition and structure of various patches (or stands), along with the capacity of forest landscape models (FLMs) to predict patterns of growth, succession, and disturbance at multiple...

  9. Transformation of a landscape in the upper mid-west, USA: The history of the St. Croix river valley, 1830 to present

    Treesearch

    Osh (Barbara) Andersen; Thomas R. Crow; Sue M. Lietz; Forest Stearns

    1996-01-01

    Learning the history of a landscape is critical to understanding present land-use patterns. We document the history of landscape change in the lower St. Croix River valley from 1830 to the present. Significant changes in land use and cover have occurred during this time. Because of the convergence of prairie, savanna and forest vegetation in this area, and because of...

  10. Contesting authority: China and the new landscape of power sector governance in the developing world

    NASA Astrophysics Data System (ADS)

    Hannam, Phillip Matthew

    development sovereignty among recipients, it can cause backsliding on safeguards and rules among established donors with consequences for power sector outcomes, making fragile movement away from carbon-intensive development even more tenuous. By characterizing this new and uncertain landscape of power sector governance, the thesis contributes to theorization on discord in international governance and to policy development for mitigating climate change.

  11. The interactions of fire regimes, land management, vegetation dynamics and the atmosphere in northern Australian savannas

    NASA Astrophysics Data System (ADS)

    Cook, Garry; Meyer, Mick

    2014-05-01

    The Australian tropical savannas burn with frequencies ranging from one in five to one in two years. Uniquely for an OECD country, these fires contribute substantially to accountable national greenhouse gas emissions. Concern about those emissions has led to the development of approaches to imprive fire management to reduce emissions and increase carbon sequestration. Savanna dyanmics are however, also determined by interactions with rainfall regimes. In this paper, we present an overview of fire regimes in northern Australia, their effects on the greenhouse gas emissions and how management of those fires interacts with climatic variability and likely climate change. Data will be presented from on-ground measurements of emissions, vegetation dyanamics as well as interpretation of satellite imagery of fire scars.

  12. The challenges associated with developing science-based landscape scale management plans

    USGS Publications Warehouse

    Szaro, R.C.; Boyce, D.A.; Puchlerz, T.

    2005-01-01

    Planning activities over large landscapes poses a complex of challenges when trying to balance the implementation of a conservation strategy while still allowing for a variety of consumptive and nonconsumptive uses. We examine a case in southeast Alaska to illustrate the breadth of these challenges and an approach to developing a science-based resource plan. Not only was the planning area, the Tongass National Forest, USA, exceptionally large (approximately 17 million acres or 6.9 million ha), but it also is primarily an island archipelago environment. The water system surrounding and going through much of the forest provides access to facilitate the movement of people, animals, and plants but at the same time functions as a barrier to others. This largest temperate rainforest in the world is an exceptional example of the complexity of managing at such a scale but also illustrates the role of science in the planning process. As we enter the 21st century, the list of questions needing scientific investigation has not only changed dramatically, but the character of the questions also has changed. Questions are contentious, cover broad scales in space and time, and are highly complex and interdependent. The provision of unbiased and objective information to all stakeholders is an important step in informed decision-making.

  13. Spectral-analysis-based extraction of land disturbances arising from oil and gas development in diverse landscapes

    NASA Astrophysics Data System (ADS)

    Zhang, Ying; Lantz, Nicholas; Guindon, Bert; Jiao, Xianfen

    2017-01-01

    Accurate and frequent monitoring of land surface changes arising from oil and gas exploration and extraction is a key requirement for the responsible and sustainable development of these resources. Petroleum deposits typically extend over large geographic regions but much of the infrastructure required for oil and gas recovery takes the form of numerous small-scale features (e.g., well sites, access roads, etc.) scattered over the landscape. Increasing exploitation of oil and gas deposits will increase the presence of these disturbances in heavily populated regions. An object-based approach is proposed to utilize RapidEye satellite imagery to delineate well sites and related access roads in diverse complex landscapes, where land surface changes also arise from other human activities, such as forest logging and agriculture. A simplified object-based change vector approach, adaptable to operational use, is introduced to identify the disturbances on land based on red-green spectral response and spatial attributes of candidate object size and proximity to roads. Testing of the techniques has been undertaken with RapidEye multitemporal imagery in two test sites located at Alberta, Canada: one was a predominant natural forest landscape and the other landscape dominated by intensive agricultural activities. Accuracies of 84% and 73%, respectively, have been achieved for the identification of well site and access road infrastructure of the two sites based on fully automated processing. Limited manual relabeling of selected image segments can improve these accuracies to 95%.

  14. Methane emission from tropical savanna Trachypogon sp. grasses

    NASA Astrophysics Data System (ADS)

    Sanhueza, E.; Donoso, L.

    2006-11-01

    Methane flux measurements from the soil-grass system were made during the wet season in unperturbed plots and plots where standing dry and green Trachypogon sp. grasses were clipped to just above the soil surface. Results support the surprising discovery that vegetation emits methane. The results of this work allows to infer that the savanna dry/green mixture of grasses produce methane at a rate of ~10 ng m-2 s-1, which is in agreement with early published soil-grass system fluxes. An extrapolation of this flux to the global savanna produces an annual emission much lower than the CH4 production recently suggested in the literature. On the other hand, during the wet season savanna soil consume CH4 at a rate of ~4.7 ng m-2 s-1. Therefore, the tropical savanna soil-grass system would make a modest contribution to the global budget of methane.

  15. Acceptability of residential development in a regional landscape: Potential effects on wildlife occupancy patterns

    USGS Publications Warehouse

    Bettigole, Charles A.; Donovan, Therese; Manning, Robert; Austin, John; Long, Robert

    2014-01-01

    The conversion of natural lands to developed uses may pose the single greatest human threat to global terrestrial biodiversity. Continued human growth and development over the next century will further exacerbate these effects of habitat loss and fragmentation. Natural resource managers are tasked with managing wildlife as a public trust, yet often have little say in land use decisions. Generally speaking, decision makers could benefit from an understanding of what different regulations mean in terms of wildlife distribution. In a previous paper (Bettigole et al., 2013), we surveyed town residents throughout Vermont to measure how respondents feel about a range of development levels within their town boundaries. We estimated the “social carrying capacity for development” – orSKd – for 251 towns in Vermont. SKd provides an estimate of the level of developed land cover classes that town residents deem “acceptable” within their town boundaries. In this paper, we design a framework for linking the town-specific SKd estimates with the wildlife distribution patterns for three wide-ranging mammalian species: American black bear (Ursus americanus), fisher (Martes pennanti), and bobcat (Lynx rufus). We simulated landscape conditions at SKd for each town in Vermont, and then used existing occupancy models for the three target species to spatially map and compare occupancy rates in the baseline year 2000 with occupancy rates at SKd. With nearly 90% of Vermont towns willing to increase developed landcover classes within town boundaries compared to baseline levels, significant state-wide changes in occupancy rates were predicted for all three focal species. Average occupancy rates declined by −15.9% and −3.1% for black bear and bobcats, respectively. Average occupancy rates for fisher increased by 9.0%. This study provides a method for linking development standards within a town with wildlife occurrence. Across towns, the methodology spatially identifies

  16. Emissions from Miombo Woodland and Dambo Grassland Savanna Fires

    NASA Technical Reports Server (NTRS)

    Sinha, Parikhit; Hobbs, Peter V.; Yokelson, Robert J.; Blake, Donald R.; Gao, Song; Kirchstetter, Thomas W.

    2004-01-01

    Airborne measurements of trace gases and particles over and downwind of two prescribed savanna fires in Zambia are described. The measurements include profiles through the smoke plumes of condensation nucleus concentrations and normalized excess mixing ratios of particles and gases, emission factors for 42 trace gases and seven particulate species, and vertical profiles of ambient conditions. The fires were ignited in plots of miombo woodland savanna, the most prevalent savanna type in southern Africa, and dambo grassland savanna, an important enclave of miombo woodland ecosystems. Emission factors for the two fires are combined with measurements of fuel loading, combustion factors, and burned area (derived from satellite burn scar retrievals) to estimate the emissions of trace gases and particles from woodland and grassland savanna fires in Zambia and southern Africa during the dry season (May-October) of 2000. It is estimated that the emissions of CO2, CO, total hydrocarbons, nitrogen oxides (NOx as NO), sulfur dioxide (SO2), formaldehyde, methyl bromide, total particulate matter, and black carbon from woodland and grassland savanna fires during the dry season of 2000 in southern Africa contributed 12.3%, 12.6%, 5.9%, 10.3%, 7.5%, 24.2%, 2.8%, 17.5%, and 11.1%, respectively, of the average annual emissions from all types of savanna fires worldwide. In 2000 the average annual emissions of methane, ethane, ethene, acetylene, propene, formaldehyde, methanol, and acetic acid from the use of biofuels in Zambia were comparable to or exceeded dry season emissions of these species from woodland and grassland savanna fires in Zambia.

  17. Landscape as a predictor of wetland condition: an evaluation of the Landscape Development Index (LDI) with a large reference wetland dataset from Ohio.

    PubMed

    Mack, John J

    2006-09-01

    Recent approaches to wetland assessment have advocated a multilevel approach which incorporates assessments based on landscape (remote sensing) data, on-site but "rapid" methods, and intensive methods where quantitative data is collected. Brown and Vivas (2004) recently pro- posed an assessment method that uses remote sensing information (Landscape Development Index or LDI) and propose that it may also be usable as a quantified human disturbance gradient. The LDI was evaluated using a large reference wetland data set from Ohio using land use percentages within a 1 km radius circle of the wetlands. The LDI had interpretable and significant relationships with another human disturbance gradient (the Ohio Rapid Assessment Method for Wetlands or ORAM) and with most metrics and scores from the Vegetation Index of Biotic Integrity (VIBI) developed for use in the State of Ohio. Metrics from emergent wetlands had the most significant correlations with the LDI (10 of 10 metrics), followed by forested wetlands (8 of 10 metrics) and shrub wetlands (4 of 10). Poor correlation for VIBI scores and metrics of shrub wetlands was due to differences in attainable LDI scores based on ecoregion and natural buffers shielding the wetland from otherwise intensive land uses. The ORAM and VIBI were developed for use in wetlands in Ohio completely independent of the LDI. It is an important test of the LDI concept that so many interpretable and significant relationships occurred between the VIBI scores, VIBI metric values, and the ORAM scores. For the purposes of VIBI development, the LDI is an independent, quantified disturbance gradient that has provided an additional test of the VIBI. Given its theoretical underpinnings and the fact that it uses quantified land use percentages, the LDI has many advantages over more qualitative human disturbance gradients. Using land use percentages from increasingly smaller distances from the wetland edge (100-200 m) may improve the resolution of the LDI

  18. Spiny plants, mammal browsers, and the origin of African savannas.

    PubMed

    Charles-Dominique, Tristan; Davies, T Jonathan; Hempson, Gareth P; Bezeng, Bezeng S; Daru, Barnabas H; Kabongo, Ronny M; Maurin, Olivier; Muasya, A Muthama; van der Bank, Michelle; Bond, William J

    2016-09-20

    Savannas first began to spread across Africa during the Miocene. A major hypothesis for explaining this vegetation change is the increase in C4 grasses, promoting fire. We investigated whether mammals could also have contributed to savanna expansion by using spinescence as a marker of mammal herbivory. Looking at the present distribution of 1,852 tree species, we established that spinescence is mainly associated with two functional types of mammals: large browsers and medium-sized mixed feeders. Using a dated phylogeny for the same tree species, we found that spinescence evolved at least 55 times. The diversification of spiny plants occurred long after the evolution of Afrotherian proboscideans and hyracoids. However, it is remarkably congruent with diversification of bovids, the lineage including the antelope that predominantly browse these plants today. Our findings suggest that herbivore-adapted savannas evolved several million years before fire-maintained savannas and probably, in different environmental conditions. Spiny savannas with abundant mammal herbivores occur in drier climates and on nutrient-rich soils, whereas fire-maintained savannas occur in wetter climates on nutrient-poor soils.

  19. Spiny plants, mammal browsers, and the origin of African savannas

    PubMed Central

    Charles-Dominique, Tristan; Davies, T. Jonathan; Hempson, Gareth P.; Bezeng, Bezeng S.; Kabongo, Ronny M.; Maurin, Olivier; Muasya, A. Muthama; van der Bank, Michelle; Bond, William J.

    2016-01-01

    Savannas first began to spread across Africa during the Miocene. A major hypothesis for explaining this vegetation change is the increase in C4 grasses, promoting fire. We investigated whether mammals could also have contributed to savanna expansion by using spinescence as a marker of mammal herbivory. Looking at the present distribution of 1,852 tree species, we established that spinescence is mainly associated with two functional types of mammals: large browsers and medium-sized mixed feeders. Using a dated phylogeny for the same tree species, we found that spinescence evolved at least 55 times. The diversification of spiny plants occurred long after the evolution of Afrotherian proboscideans and hyracoids. However, it is remarkably congruent with diversification of bovids, the lineage including the antelope that predominantly browse these plants today. Our findings suggest that herbivore-adapted savannas evolved several million years before fire-maintained savannas and probably, in different environmental conditions. Spiny savannas with abundant mammal herbivores occur in drier climates and on nutrient-rich soils, whereas fire-maintained savannas occur in wetter climates on nutrient-poor soils. PMID:27601649

  20. Landscape assessment for tourism

    Treesearch

    Clare A. Gunn

    1979-01-01

    Increased development of landscapes for tourism now creates problems of integrating the many parts. Accomplishments at the site scale have not been matched with equal progress at the regional scale. This concept, and its example of application, shows promise of assisting regions in assessing their potential of landscapes before development. With such a concept, not...

  1. From landscape to domain: Soils role in landscape classifications

    USDA-ARS?s Scientific Manuscript database

    Soil landscape classifications are designed to divide landscapes into units with significance for the provisioning and regulating of ecosystem services and the development of conservation plans for natural resources. More specifically, such classifications serve as the basis for stratifying manageme...

  2. Seasonality of semi-arid and savanna-type ecosystems in an Earth system model

    NASA Astrophysics Data System (ADS)

    Dahlin, K.; Swenson, S. C.; Lombardozzi, D.; Kamoske, A.

    2016-12-01

    Recent work has identified semi-arid and savanna-type (SAST) ecosystems as a critical component of interannual variability in the Earth system (Poulter et al. 2014, Ahlström et al. 2015), yet our understanding of the spatial and temporal patterns present in these systems remains limited. There are three major factors that contribute to the complex behavior of SAST ecosystems, globally. First is leaf phenology, the timing of the appearance, presence, and senescence of plant leaves. Plants grow and drop their leaves in response to a variety of cues, including soil moisture, rainfall, day length, and relative humidity, and alternative phenological strategies might often co-exist in the same location. The second major factor in savannas is soil moisture. The complex nature of soil behavior under extremely dry, then extremely wet conditions is critical to our understanding of how savannas function. The third factor is fire. Globally, virtually all savanna-type ecosystems operate with some non-zero fire return interval. Here we compare model output from the Community Land Model (CLM5-BGC) in SAST regions to remotely sensed data on these three variables - phenology (MODIS LAI), soil moisture (SMAP), and fire (GFED4) - assessing both annual spatial patterns and intra-annual variability, which is critical in these highly variable systems. We present new SAST-specific first- and second-order benchmarks, including numbers of annual LAI peaks (often >1 in SAST systems) and correlations between soil moisture, LAI, and fire. Developing a better understanding of how plants respond to seasonal patterns is a critical first step in understanding how SAST ecosystems will respond to and influence climate under future scenarios.

  3. Surficial Geology and Landscape Development in Northern Frenchman Flat, Interim Summary and Soil Data

    SciTech Connect

    Raytheon Services Nevada Environmental Restoration and Waste Management Division

    1995-09-01

    This report summarizes geologic studies by Raytheon Services Nevada near the Area 5 Radioactive Waste Management Site at the Nevada Test Site. These studies are part of a program to satisfy data needs of (1) the Greater Confinement Disposal (GCD) Program Performance Assessment (PA), (2) the low-level waste (LLW) PA, and (3) the Resource Conservation and Recovery Act (RCRA) permit application. The geologic studies were integrated into a single program that worked toward a landscape evolution model of northern Frenchman Flat, with more detailed geologic studies of particular topics as needed. Only the Holocene tectonism and surficial geology components of the landscape model are presented in this report.

  4. Disentangling fragmentation effects on herbivory in understory plants of longleaf pine savanna.

    PubMed

    Levey, Douglas J; Caughlin, T Trevor; Brudvig, Lars A; Haddad, Nick M; Damschen, Ellen I; Tewksbury, Joshua J; Evans, Daniel M

    2016-09-01

    Habitat fragmentation affects species and their interactions through intertwined mechanisms that include changes to fragment area, shape, connectivity and distance to edge. Disentangling these pathways is a fundamental challenge of landscape ecology and will help identify ecological processes important for management of rare species or restoration of fragmented habitats. In a landscape experiment that manipulated connectivity, fragment shape, and distance to edge while holding fragment area constant, we examined how fragmentation impacts herbivory and growth of nine plant species in longleaf pine savanna. Probability of herbivory in open habitat was strongly dependent on proximity to forest edge for every species, increasing with distance to edge in six species (primarily grasses and annual forbs) and decreasing in three species (perennial forbs and a shrub). In the two species of perennial forbs, these edge effects were dependent on fragment shape; herbivory strongly decreased with distance to edge in fragments of two shapes, but not in a third shape. For most species, however, probability of herbivory was unrelated to connectivity or fragment shape. Growth was generally determined more strongly by leaf herbivory than by distance to edge, fragment shape, or connectivity. Taken together, these results demonstrate consistently strong edge effects on herbivory, one of the most important biotic factors determining plant growth and demography. Our results contrast with the generally inconsistent results of observational studies, likely because our experimental approach enabled us to tease apart landscape processes that are typically confounded. © 2016 by the Ecological Society of America.

  5. Studying Wildlife at Local and Landscape Scales: Bachman's Sparrow at the Savannah River Site

    SciTech Connect

    Dunning, J.B.; Danielson, B.J.; Watts, B.D.; Liu, J.; Krementz, D.R.

    2000-10-01

    Mutual interests between land managers at SRS and scientists resulted in a landscape ecology study of Bachman's sparrow. The species is declining throughout it's range. The distribution of suitable habitats across the landscape may provide an explanation. The species occupies early successional and late successional savanna habitat. Modeling was closely linked to field observations to demonstrate how the species demographics change with the distribution and dynamics of habitats.

  6. The chromatin landscape of the moss Physcomitrella patens and its dynamics during development and drought stress.

    PubMed

    Widiez, Thomas; Symeonidi, Aikaterini; Luo, Chongyuan; Lam, Eric; Lawton, Michael; Rensing, Stefan A

    2014-07-01

    The moss Physcomitrella patens is an important model organism for evo-devo studies. Here, we determined the genome-wide chromatin landscape of five important histone three (H3) modifications (H3K4me3, H3K27me3, H3K27Ac, H3K9Ac and H3K9me2) and describe the changes to these histone marks in two contrasted situations, developmental transition and abiotic (drought) stress. Integrative analysis of these histone H3 modifications revealed their preferential association into 15 chromatin states (CS) in genic regions of the P. patens genome. Synergistic relationships that influence expression levels were revealed for the three activating marks H3K4me3, H3K27Ac and H3K9Ac, while an antagonistic relationship was found between CS containing the H3K27me3 and H3K27Ac marks, suggesting that H3K27 is a key indexing residue regarding transcriptional output. Concerning the alteration of histone marks in response to developmental transition (juvenile to adult) and drought stress, the three activating marks H3K4me3, H3K27Ac and H3K9Ac show significant changes in both situations. However, changes to H3K27me3 are central only for genes differentially expressed during development. Interestingly, genes induced during drought stress show significant histone mark toggling during developmental transition. This situation suggests that drought induced adult (gametophore expressed) genes are primed to respond to this stress during the juvenile to adult transition.

  7. Late Quaternary landscape development at the margin of the Pomeranian phase (MIS 2) near Lake Wygonin (Northern Poland)

    NASA Astrophysics Data System (ADS)

    Hirsch, Florian; Schneider, Anna; Nicolay, Alexander; Błaszkiewicz, Mirosław; Kordowski, Jarosław; Noryskiewicz, Agnieszka M.; Tyszkowski, Sebastian; Raab, Alexandra; Raab, Thomas

    2015-04-01

    In Central Europe, Late Quaternary landscapes experienced multiple phases of geomorphologic activity. In this study,we used a combined geomorphological, pedological, sedimentological and palynological approach to characterize landscape development after the Last Glacial Maximum (LGM) near Lake Wygonin in Northern Poland. The pedostratigraphical findings from soil pits and drillings were extrapolated using ground-penetrating radar (GPR) and electric resistivity tomography (ERT). During the Pomeranian phase, glacial and fluvioglacial processes dominated the landscape near Lake Wygonin. At the end of the glacial period, periglacial processes became relevant and caused the formation of ventifacts and coversands containing coated sand grains. At approximately 15,290-14,800 cal yr BP, a small pond formed in a kettle hole (profile BWI2). The lacustrine sediments lack eolian sand components and therefore indicate the decline of eolian processes during that time. The increase of Juniperus and rock-rose (Helianthemum) in the pollen diagram is a prominent marker of the Younger Dryas. At the end of the Younger Dryas, a partial reshaping of the landscape is indicated by abundant charcoal fragments in disturbed lake sediments. No geomorphologic activity since the beginning of the Holocene is documented in the terrestrial and wetland archives. The anthropogenic impact is reflected in the pollen diagram by the occurrence of rye pollen grains (Cerealia type, Secale cereale) and translocated soil sediments dated to 1560-1410 cal yr BP, proving agricultural use of the immediate vicinity. With the onset of land use, gully incision and the accumulation of colluvial fans reshaped the landscape locally. Since 540-460 cal yr BP, further gully incision in the steep forest tracks has been associated with the intensification of forestry. Outside of the gully catchments, the weakly podzolized Rubic Brunic Arenosols show no features of Holocene soil erosion. Reprinted from CATENA, Volume 124

  8. Development of hydrologic landscape regions for classifying hydrologic permanace and hydrological-ecological interactions

    EPA Science Inventory

    In a 2001 paper, Winter proposed the concept of the hydrologic landscape unit as a fundamental unit composed of an upland and lowland separated by a steeper slope. Winter suggested that this concept could be useful for hydrologic research, data analysis, and comparing hydrologic...

  9. Development of hydrologic landscape regions for classifying hydrologic permanace and hydrological-ecological interactions

    EPA Science Inventory

    In a 2001 paper, Winter proposed the concept of the hydrologic landscape unit as a fundamental unit composed of an upland and lowland separated by a steeper slope. Winter suggested that this concept could be useful for hydrologic research, data analysis, and comparing hydrologic...

  10. Developing a Spatial Perspective: Using the Local Landscape To Teach Students to Think Geographically.

    ERIC Educational Resources Information Center

    Hermann, Dan

    1996-01-01

    Summarizes methods from a high school geography class that used examples from local geography to teach basic geographic concepts. Maintains that these illustrative examples can be used even in courses where the content is not local geography. Provides examples of local landscapes illustrating concepts applicable to the Brazilian rain forest. (MJP)

  11. The Singapore Global Schoolhouse: An Analysis of the Development of the Tertiary Education Landscape in Singapore

    ERIC Educational Resources Information Center

    Ng, Pak Tee; Tan, Charlene

    2010-01-01

    Purpose: This paper seeks to analyse the Singapore government's recent attempt to make Singapore a "Global Schoolhouse" by transforming its tertiary education sector. It aims to examine the government's attempt to promote greater diversity and autonomy in the tertiary education landscape; it also aims to examine the government's systems…

  12. The Singapore Global Schoolhouse: An Analysis of the Development of the Tertiary Education Landscape in Singapore

    ERIC Educational Resources Information Center

    Ng, Pak Tee; Tan, Charlene

    2010-01-01

    Purpose: This paper seeks to analyse the Singapore government's recent attempt to make Singapore a "Global Schoolhouse" by transforming its tertiary education sector. It aims to examine the government's attempt to promote greater diversity and autonomy in the tertiary education landscape; it also aims to examine the government's systems…

  13. Development of a technique for classification of integumentary elements of a landscape

    NASA Astrophysics Data System (ADS)

    Voloshyn, V. I.; Bushuyev, Ye. I.; Parshyna, O. I.

    Methodical maintenance for classification of integumentary elements of a landscape is considered on the basis of data of the Earth's remote sensing as the primary goal of management of territory. The classes of integumentary elements and technological operations of satellite data processing are listed.

  14. Soil-landscape development and late Quaternary environmental change in coastal Estremadura, Portugal

    NASA Astrophysics Data System (ADS)

    Daniels, Michael; Haws, Jonathan; Benedetti, Michael; Bicho, Nuno

    2015-04-01

    This poster integrates soil-landscape analysis with archaeological survey and paleoenvironmental reconstruction. Soils in surface and buried contexts in Estremadura, Portugal, provide evidence of landscape stability and instability, relative age relationships between landforms, and general paleoenvironmental conditions during the late Quaternary. These factors provide insight into the distribution and condition of Paleolithic archaeological sites and help understand the record of human settlement in the region. Late Pleistocene and Holocene dunes extend inland approximately 10 km from coastal source regions. Surface soils in Holocene dunes under maritime pine (Pinus pinaster) forest exhibit A, E, C/Bh and A, C horizon sequences and classify as Quartzipsamments. Surface soils in late Pleistocene dunes exhibit A, E, Bh, Bhs, Bs horizon sequences and classify as Haplorthods. Both Pleistocene and Holocene dunes commonly bury a heavily weathered soil formed in calcareous sandstone. The boundary between underlying buried soils and overlying surface soils is characterized by a lag deposit of medium to coarse, moderately-rounded gravels, underlain immediately by subsurface Bt and Bss horizons. The lag deposit and absence of buried A horizons both indicate intense and/or prolonged surface erosion prior to burial by late Quaternary dunes. Soil-geomorphic relationships therefore suggest at least two distinct episodes of dune emplacement and subsequent landscape stability following an extensive episode late Pleistocene landscape instability and soil erosion. A conceptual model of soil-landscape evolution through the late Quaternary and Holocene results from the integration of soil profile data, proxy paleoenvironmental data, and the partial record of human settled as revealed in the archaeological record.

  15. An improved neutral landscape model for recreating real landscapes and generating landscape series for spatial ecological simulations.

    PubMed

    van Strien, Maarten J; Slager, Cornelis T J; de Vries, Bauke; Grêt-Regamey, Adrienne

    2016-06-01

    Many studies have assessed the effect of landscape patterns on spatial ecological processes by simulating these processes in computer-generated landscapes with varying composition and configuration. To generate such landscapes, various neutral landscape models have been developed. However, the limited set of landscape-level pattern variables included in these models is often inadequate to generate landscapes that reflect real landscapes. In order to achieve more flexibility and variability in the generated landscapes patterns, a more complete set of class- and patch-level pattern variables should be implemented in these models. These enhancements have been implemented in Landscape Generator (LG), which is a software that uses optimization algorithms to generate landscapes that match user-defined target values. Developed for participatory spatial planning at small scale, we enhanced the usability of LG and demonstrated how it can be used for larger scale ecological studies. First, we used LG to recreate landscape patterns from a real landscape (i.e., a mountainous region in Switzerland). Second, we generated landscape series with incrementally changing pattern variables, which could be used in ecological simulation studies. We found that LG was able to recreate landscape patterns that approximate those of real landscapes. Furthermore, we successfully generated landscape series that would not have been possible with traditional neutral landscape models. LG is a promising novel approach for generating neutral landscapes and enables testing of new hypotheses regarding the influence of landscape patterns on ecological processes. LG is freely available online.

  16. Soil Development Over Mud-rich Rocks Produces Landscape-scale Erosional Instabilities in the Northern Gabilan Mesa

    NASA Astrophysics Data System (ADS)

    Johnstone, S. A.; Miguel, F.; Hilley, G. E.

    2015-12-01

    Whether landscapes respond to climatic and tectonic perturbations through steady, continuous adjustment or by short-lived, transiently unstable acceleration of erosion rates is fundamental to understanding landscape dynamics and the impact that land-use change may have on watershed sediment budgets. We document the geomorphic response of catchments in the Northern Gabilan Mesa (NGM), where it appears that over geomorphic timescales, well-developed soils may provide more resistance to incision than the mudstones from which they were derived. While measures of tensile strength reveal that intact mudstone is stronger than overlying soils, slaking removes the internal strength of these mudstones. This produces materials in the critical zone that are weaker than the overlying soils. This local configuration appears to impact large-scale landscape dynamics in the NGM, in that once the cohesive soils are locally removed, gullies that incise into the underlying, weaker slaked rock undermine the cohesive soil mantle and propagate headward as a series of arroyos predominantly hosted on south-facing slopes. These arroyos are more frequent in landscapes underlain by shallow marine mudstones and sandstones than sandstones and conglomerates. On the walls of arroyos, the development of relief and the exposure of rapidly disintegrating bedrock is accompanied by the dominance of transport by granular flows. Finally, arroyos often extend farther upslope than do channels without bedrock exposures, ultimately causing an increase in drainage density. Therefore in a situation where cohesive soils overlie a zone of weaker weathered material, incision through the cohesive layer represents a threshold that initiates a transient wave of incision that rapidly undermines and removes large volumes of bedrock and soil. This conceptual model is affirmed by simple one-dimensional geomorphic models that explore the conditions under which such features may be produced.

  17. Aerosol emissions by tropical forest and savanna biomass burning: Characteristic trace elements and fluxes

    SciTech Connect

    Echalar, F.; Gaudichet, A.; Cachier, H.

    1995-11-15

    This report characterizes and compares trace element emissions from fires of three different types of savannas and from the southwestern amazonian rain forest. This study tries to verify a fingerprint that may characterize savanna fires or tropical biomass burning.

  18. Application of Unsupervised Clustering using Sparse Representations on Learned Dictionaries to develop Land Cover Classifications in Arctic Landscapes

    NASA Astrophysics Data System (ADS)

    Rowland, J. C.; Moody, D. I.; Brumby, S.; Gangodagamage, C.

    2012-12-01

    Techniques for automated feature extraction, including neuroscience-inspired machine vision, are of great interest for landscape characterization and change detection in support of global climate change science and modeling. Successful application of novel unsupervised feature extraction and clustering algorithms for use in Land Cover Classification requires the ability to determine what landscape attributes are represented by automated clustering. A closely related challenge is learning how to precondition the input data streams to the unsupervised classification algorithms in order to obtain clusters that represent Land Cover category of relevance to landsurface change and modeling applications. We present results from an ongoing effort to apply novel clustering methodologies developed primarily for neuroscience machine vision applications to the environmental sciences. We use a Hebbian learning rule to build spectral-textural dictionaries that are adapted to the data. We learn our dictionaries from millions of overlapping image patches and then use a pursuit search to generate sparse classification features. These sparse representations of pixel patches are used to perform unsupervised k-means clustering. In our application, we use 8-band multispectral Worldview-2 data from three arctic study areas: Barrow, Alaska; the Selawik River, Alaska; and a watershed near the Mackenzie River delta in northwest Canada. Our goal is to develop a robust classification methodology that will allow for the automated discretization of the landscape into distinct units based on attributes such as vegetation, surface hydrological properties (e.g. soil moisture and inundation), and topographic/geomorphic characteristics. The challenge of developing a meaningful land cover classification includes both learning how optimize the clustering algorithm and successfully interpreting the results. In applying the unsupervised clustering, we have the flexibility of selecting both the window

  19. Similar alpha and beta diversity changes in tropical ant communities, comparing savannas and rainforests in Brazil and Indonesia.

    PubMed

    Schmidt, Fernando A; Ribas, Carla R; Sobrinho, Tathiana G; Ubaidillah, Rosichon; Schoereder, José H; Clough, Yann; Tscharntke, Teja

    2017-10-04

    Local biodiversity can be expected to be similar worldwide if environmental conditions are similar. Here, we hypothesize that tropical ant communities with different types of regional species pools but at similar habitat types in Brazil and Indonesia show similar diversity patterns at multiple spatial scales, when comparing (1) the relative contribution of alpha and beta diversity to gamma diversity; (2) the number of distinct communities (community differentiation); and (3) the drivers of β-diversity (species replacement or species loss/gain) at each spatial scale. In both countries, rainforests and savannas (biome scale) were represented by three landscapes (landscape scale), each with four transects (site scale) and each transect with 10 pitfall traps (local scale). At the local scale, α-diversity was higher and β-diversity lower than expected from null models. Hence, we observed a high coexistence of species across biomes. The replacement of species seemed the most important factor for β-diversity among sites and among landscapes across biomes. Species sorting, landscape-moderated species distribution and neutral drift are potential mechanisms for the high β-diversity among sites within landscapes. At the biome scale, different evolutionary histories produced great differences in ant community composition, so the replacement of species is, at this scale, the most important driver of beta diversity. According to these key findings, we conclude that distinct regional ant species pools from similar tropical habitat types are similarly constrained across several spatial scales, regardless of the continent considered.

  20. Quantifying the relative importance of greenhouse gas emissions from current and future savanna land use change across northern Australia

    NASA Astrophysics Data System (ADS)

    Bristow, Mila; Hutley, Lindsay B.; Beringer, Jason; Livesley, Stephen J.; Edwards, Andrew C.; Arndt, Stefan K.

    2016-11-01

    The clearing and burning of tropical savanna leads to globally significant emissions of greenhouse gases (GHGs); however there is large uncertainty relating to the magnitude of this flux. Australia's tropical savannas occupy the northern quarter of the continent, a region of increasing interest for further exploitation of land and water resources. Land use decisions across this vast biome have the potential to influence the national greenhouse gas budget. To better quantify emissions from savanna deforestation and investigate the impact of deforestation on national GHG emissions, we undertook a paired site measurement campaign where emissions were quantified from two tropical savanna woodland sites; one that was deforested and prepared for agricultural land use and a second analogue site that remained uncleared for the duration of a 22-month campaign. At both sites, net ecosystem exchange of CO2 was measured using the eddy covariance method. Observations at the deforested site were continuous before, during and after the clearing event, providing high-resolution data that tracked CO2 emissions through nine phases of land use change. At the deforested site, post-clearing debris was allowed to cure for 6 months and was subsequently burnt, followed by extensive soil preparation for cropping. During the debris burning, fluxes of CO2 as measured by the eddy covariance tower were excluded. For this phase, emissions were estimated by quantifying on-site biomass prior to deforestation and applying savanna-specific emission factors to estimate a fire-derived GHG emission that included both CO2 and non-CO2 gases. The total fuel mass that was consumed during the debris burning was 40.9 Mg C ha-1 and included above- and below-ground woody biomass, course woody debris, twigs, leaf litter and C4 grass fuels. Emissions from the burning were added to the net CO2 fluxes as measured by the eddy covariance tower for other post-deforestation phases to provide a total GHG emission from

  1. Landscape development in Southern Peninsular India from 10Be denudation rates in river sands

    NASA Astrophysics Data System (ADS)

    Mandal, Sanjay; Lupker, Maarten; Haghipour, Negar; Burg, Jean-Pierre; Christl, Marcus

    2014-05-01

    The persistence of high elevation and topography observed along many passive margins remains one of the outstanding problems in landscape evolution. In Southern Peninsular India, this question revolves around the understanding of whether the observed high relief and pronounced topography results from equilibrium with contemporaneous external forcing or whether the relief was acquired during the late Cenozoic and conserved over several tens of millions years. Modern denudation rates dictating the current landscape evolution are ruled by the interactions between climate, tectonics and rock strength. We used detrital cosmogenic 10Be from 43 drainage basins ranging in size from 4 to 68768 km2, to infer millennial averaged denudation rates along and across the Western Ghat Mountains in Southern India and to understand if the present landscape is still actively evolving or not. The Western Ghat is characterized by a W-E gradient in relief and rainfall with only minor variations in lithology allowing to isolate the relationship between erosion rates and topographic indices. Cosmogenic-derived erosion rates are spatially variable, ranging from ~8 to 77 mm/ka on the western side and 8 to 51 mm/ka on the eastern side. The rugged topography of Western Ghats and Nilgiri Mountains exhibit pronounced topography in conjunction with low denudation rates. This represents an exception to the often-cited general coupling of topography and denudation rates and suggests that steep slopes and high relief in passive margin settings are not associated to high denudation. Nevertheless, locally the differences in denudation rates along and across the Western Ghats are well correlated with local relief, which suggests that the inherited topography still controls current denudation rates. Even though the catchments in Western Ghats receive a mean annual precipitation ~ 5 m, due to the SW Indian monsoon, precipitation shows only a minor control on denudation rates. This suggests that in the

  2. Descriptive approaches to landscape analysis

    Treesearch

    R. Burton Litton Jr.

    1979-01-01

    Descriptive landscape analyses include various procedures used to document visual/scenic resources. Historic and regional examples of landscape description represent desirable insight for contemporary professional inventory work. Routed and areal landscape inventories are discussed as basic tools. From them, qualitative and quantitative evaluations can be developed...

  3. A Forest Landscape Visualization System

    Treesearch

    Tim McDonald; Bryce Stokes

    1998-01-01

    A forest landscape visualization system was developed and used in creating realistic images depicting how an area might appear if harvested. The system uses a ray-tracing renderer to draw model trees on a virtual landscape. The system includes components to create landscape surfaces from digital elevation data, populate/cut trees within (polygonal) areas, and convert...

  4. Characterization of hundreds of regulatory landscapes in developing limbs reveals two regimes of chromatin folding.

    PubMed

    Andrey, Guillaume; Schöpflin, Robert; Jerković, Ivana; Heinrich, Verena; Ibrahim, Daniel M; Paliou, Christina; Hochradel, Myriam; Timmermann, Bernd; Haas, Stefan; Vingron, Martin; Mundlos, Stefan

    2017-02-01

    Complex regulatory landscapes control the pleiotropic transcriptional activities of developmental genes. For most genes, the number, location, and dynamics of their associated regulatory elements are unknown. In this work, we characterized the three-dimensional chromatin microarchitecture and regulatory landscape of 446 limb-associated gene loci in mouse using Capture-C, ChIP-seq, and RNA-seq in forelimb, hindlimb at three developmental stages, and midbrain. The fine mapping of chromatin interactions revealed a strong preference for functional genomic regions such as repressed or active domains. By combining chromatin marks and interaction peaks, we annotated more than 1000 putative limb enhancers and their associated genes. Moreover, the analysis of chromatin interactions revealed two regimes of chromatin folding, one producing interactions stable across tissues and stages and another one associated with tissue and/or stage-specific interactions. Whereas stable interactions associate strongly with CTCF/RAD21 binding, the intensity of variable interactions correlates with changes in underlying chromatin modifications, specifically at the viewpoint and at the interaction site. In conclusion, this comprehensive data set provides a resource for the characterization of hundreds of limb-associated regulatory landscapes and a framework to interpret the chromatin folding dynamics observed during embryogenesis.

  5. Implication of Forest-Savanna Dynamics on Biomass and Carbon Stock: Effectiveness of an Amazonian Ecological Station

    NASA Astrophysics Data System (ADS)

    Couto-Santos, F. R.; Luizao, F. J.

    2014-12-01

    The forests-savanna advancement/retraction process seems to play an important role in the global carbon cycle and in the climate-vegetation balance maintenance in the Amazon. To contribute with long term carbon dynamics and assess effectiveness of a protected area in reduce carbon emissions in Brazilian Amazon transitional areas, variations in forest-savanna mosaics biomass and carbon stock within Maraca Ecological Station (MES), Roraima/Brazil, and its outskirts non-protected areas were compared. Composite surface soil samples and indirect methods based on regression models were used to estimate aboveground tree biomass accumulation and assess vegetation and soil carbon stock along eleven 0.6 ha transects perpendicular to the forest-savanna limits. Aboveground biomass and carbon accumulation were influenced by vegetation structure, showing higher values within protected area, with great contribution of trees above 40 cm in diameter. In the savanna environments of protected areas, a higher tree density and carbon stock up to 30 m from the border confirmed a forest encroachment. This pointed that MES acts as carbon sink, even under variations in soil fertility gradient, with a potential increase of the total carbon stock from 9 to 150 Mg C ha-1. Under 20 years of fire and disturbance management, the results indicated the effectiveness of this protected area to reduce carbon emissions and mitigate greenhouse and climate change effects in a forest-savanna transitional area in Brazilian Northern Amazon. The contribution of this study in understanding rates and reasons for biomass and carbon variation, under different management strategies, should be considered the first approximation to assist policies of reducing emissions from deforestation and forest degradation (REDD) from underresearched Amazonian ecotone; despite further efforts in this direction are still needed. FINANCIAL SUPPORT: Boticário Group Foundation (Fundação Grupo Boticário); National Council for

  6. Seasonal, inter-annual and decadal drivers of tree and grass productivity in an Australian tropical savanna.

    NASA Astrophysics Data System (ADS)

    Moore, C.; Beringer, J.; Hutley, L. B.; Evans, B. J.; Tapper, N. J.; Donohue, R. J.; Exbrayat, J. F.

    2016-12-01

    Tree-grass savannas are a widespread biome and are highly valued for their ecosystem services. Natural or anthropogenic shifts in the savanna tree-grass ratio have wide-reaching implications for food production, timber harvesting, biodiversity, the water cycle and carbon sequestration. It is important to understand the long-term dynamics and drivers of both tree and grass productivity separately, in order to successfully manage savannas in the future. This study investigates the inter-annual variability (IAV) of tree (overstory) and grass (understory) productivity at the Howard Springs OzFlux/Fluxnet site by combining a long-term (15 year) eddy covariance flux record and DIFFUSE model estimates of tree and grass productivity inferred from satellite remote sensing. On a seasonal basis, the primary drivers of overstory and understory productivity were solar radiation in the wet season and soil moisture in the dry season, with deeper soil layers becoming more important as the dry season progressed. On an inter-annual basis, variability in the amount of annual rainfall and length of the rainy season determined soil water availability, which had a positive effect on overstory productivity and a negative effect on understory productivity. No linear trend in the tree-grass ratio was observed over the 15-year study period, indicating that woody encroachment was not occurring to a significant degree at the study site. However, the tree-grass ratio was well correlated with modes of climate variability, namely the Southern Oscillation Index. This study has provided important insight into the long-term contributions of trees and grasses to savanna productivity, along with the respective drivers of IAV. The results will contribute towards model development and building better links with remote sensing techniques in order to more comprehensively monitor savanna structure and function across space and time.

  7. The role of savannas in the terrestrial Si cycle: A case-study from Lamto, Ivory Coast

    NASA Astrophysics Data System (ADS)

    Alexandre, A. E.; Abbadie, L.

    2011-12-01

    Savannas currently occupy a fifth of the earth's land surface and are predicted to expand in the next few centuries at the expense of tropical forests, mainly as a result of deforestation and human fires. Can such a vegetation trend impact, through changes in plant Si cycling, the lithogenic silicon (LSi) release into soils (through chemical weathering) and the net dissolved Si (DSi) outputs from soils to stream water (through chemical denudation)? The first step of an investigation requires quantifying the net Si fluxes involved in the plant/soil system. Here, a schematic steady-state Si cycle, established for a tropical humid savanna (Lamto, Ivory Coast) that developed on a ferruginous soil and is subjected to annual fires, is presented. Erosion was assumed to be insignificant. LSi and biogenic Si (BSi under the form of phytoliths) pools were measured, and Si fluxes were estimated from Si concentrations and mass balance calculation. Identification of plant and soil phytoliths indicated that the soil BSi pool is in equilibrium with the current BSi input by the savanna. In the soil column, mixing between a young rapidly recycled BSi pool and an old stable BSi pool is attested by a mixing line equation. Storage of the old BSi pool is assimilated as a BSi output from the plant/soil system. A BSi output additionally occurs after annual fires, when ashes are exported. Both BSi outputs decrease as much the BSi dissolution. In order to uptake constant DSi flux, the savanna increases by three to eight times the net LSi release, depending upon the post-fire ash exportation scenario. A comparison between savanna and rainforest Si cycles that maximizes the differences in plant/soil systems and minimizes differences in climate is presented. The comparison revealed that BSi storage is higher in the savanna soil than in the rainforest soil, mainly due to BSi production that is twice higher in the savanna (127 vs 67 kg/ha/yr). The resulting LSi release that is enhanced by plant

  8. The role of savannas in the terrestrial Si cycle: A case-study from Lamto, Ivory Coast

    NASA Astrophysics Data System (ADS)

    Alexandre, Anne; Bouvet, Mickael; Abbadie, Luc

    2011-08-01

    Savannas currently occupy a fifth of the earth's land surface and are predicted to expand in the next few centuries at the expense of tropical forests, mainly as a result of deforestation and human fires. Can such a vegetation trend impact, through changes in plant Si cycling, the lithogenic silicon (LSi) release into soils (through chemical weathering) and the net dissolved Si (DSi) outputs from soils to stream water (through chemical denudation)? The first step of an investigation requires quantifying the net Si fluxes involved in the plant/soil system. Here, a schematic steady-state Si cycle, established for a tropical humid savanna (Lamto, Ivory Coast) that developed on a ferruginous soil and is subjected to annual fires, is presented. Erosion was assumed to be insignificant. LSi and biogenic Si (BSi under the form of phytoliths) pools were measured, and Si fluxes were estimated from Si concentrations and mass balance calculation. Identification of plant and soil phytoliths indicated that the soil BSi pool is in equilibrium with the current BSi input by the savanna. In the soil column, mixing between a young rapidly recycled BSi pool and an old stable BSi pool is attested by a mixing line equation. Storage of the old BSi pool is assimilated as a BSi output from the plant/soil system. A BSi output additionally occurs after annual fires, when ashes are exported. Both BSi outputs decrease as much the BSi dissolution. In order to uptake constant DSi flux, the savanna increases by three to eight times the net LSi release, depending upon the post-fire ash exportation scenario. A comparison between savanna and rainforest Si cycles that maximizes the differences in plant/soil systems and minimizes differences in climate is presented. The comparison revealed that BSi storage is higher in the savanna soil than in the rainforest soil, mainly due to BSi production that is twice higher in the savanna (127 vs 67 kg/ha/yr). The resulting LSi release that is enhanced by plant

  9. A new symbol-and-GIS based detailed geomorphological mapping system: Renewal of a scientific discipline for understanding landscape development

    NASA Astrophysics Data System (ADS)

    Gustavsson, Marcus; Kolstrup, Else; Seijmonsbergen, Arie C.

    2006-07-01

    This paper presents a comprehensive and flexible new geomorphological combination legend that expands the possibilities of current geomorphological mapping concepts. The new legend is presented here at scale of 1:10,000 and it combines symbols for hydrography, morphometry/morphography, lithology and structure with colour variations for process/genesis and geologic age. The piece-by-piece legend forms a "geomorphological alphabet" that offers a high diversity of geomorphological information and a possibility for numerous combinations of information. This results in a scientific map that is rich in data and which is more informative than most previous maps but is based on a simple legend. The system is developed to also be used as a basis for applications in GIS. The symbol-based information in the geomorphological maps can be digitally stored as a powerful database with thematic layers and attribute tables. By combining and further developing aspects of different classical mapping systems and techniques into expanded data combinations, new possibilities of presentation and storage are developed and thus a strong scientific tool is provided for landscape configuration and the reconstruction of its development; in turn the combination paves the way for specific thematic applications. The new system is illustrated for two contrasting landscape types: the first is located on the border of Vorarlberg, western Austria, and Liechtenstein in a glacially influenced, high altitude alpine setting that is strongly modified by various degradation processes; the second area represents a formerly glaciated region in Dalarna, central Sweden near Mora, an area that is characterized by a variety of aeolian, fluvial, glaciofluvial and lacustrine depositional and erosional landforms and also reflects isostatic uplift. The new method functions well for both areas and results in detailed scientific outlines of both landscape types.

  10. Anthelmintic activity of plant extracts from Brazilian savanna.

    PubMed

    Oliveira, Andreia F; Costa Junior, Livio M; Lima, Aldilene S; Silva, Carolina R; Ribeiro, Maria N S; Mesquista, José W C; Rocha, Cláudia Q; Tangerina, Marcelo M P; Vilegas, Wagner

    2017-03-15

    Helminth infections represent a serious problem for the production of small ruminants that is currently aggravated by resistance to anthelmintic products and has induced a search for control alternatives, such as natural products. In this study, extracts of Turnera ulmifolia L. (leaves and roots), Parkia platycephala Benth. (leaves and seeds) and Dimorphandra gardneriana Tul. (leaves and bark), which have been cited in ethnoveterinary studies and selected naturally by goats in the cerrado (Brazilian savanna), were tested in vitro against Haemonchus contortus. Hydroacetonic (ACT) and hydroalcoholic (ETH) extracts were evaluated using an Egg Hatching Assay (EHA), a Larval Exsheathment Inhibition Assay (LEIA) and a Larval Development Assay (LDA). A second set of incubations was performed using polyvinylpolypyrrolidone (PVPP) to determine the influence of polyphenols on the anthelmintic effects of EHA and LEIA. Data from each extract were used to calculate inhibition concentrations (IC50). All tested extracts showed activity against at least one life stage of H. contortus. The use of PVPP revealed that the tannins are not the only extracts of secondary metabolites responsible for the anthelmintic effects. The results showed clear in vitro anthelmintic activities against H. contortus at different stages and indicated the potential use of these species as a promising alternative approach to control helminthic infections of small ruminants.

  11. Landscape disturbance from unconventional and conventional oil and gas development in the Marcellus Shale region of Pennsylvania, USA

    USGS Publications Warehouse

    Slonecker, Terry E.; Milheim, Lesley E.

    2015-01-01

    The spatial footprint of unconventional (hydraulic fracturing) and conventional oil and gas development in the Marcellus Shale region of the State of Pennsylvania was digitized from high-resolution, ortho-rectified, digital aerial photography, from 2004 to 2010. We used these data to measure the spatial extent of oil and gas development and to assess the exposure of the extant natural resources across the landscape of the watersheds in the study area. We found that either form of development: (1) occurred in ~50% of the 930 watersheds that defined the study area; (2) was closer to streams than the recommended safe distance in ~50% of the watersheds; (3) was in some places closer to impaired streams and state-defined wildland trout streams than the recommended safe distance; (4) was within 10 upstream kilometers of surface drinking water intakes in ~45% of the watersheds that had surface drinking water intakes; (5) occurred in ~10% of state-defined exceptional value watersheds; (6) occurred in ~30% of the watersheds with resident populations defined as disproportionately exposed to pollutants; (7) tended to occur at interior forest locations; and (8) had >100 residents within 3 km for ~30% of the unconventional oil and gas development sites. Further, we found that exposure to the potential effects of landscape disturbance attributable to conventional oil and gas development was more prevalent than its unconventional counterpart.

  12. Methane emission from tropical savanna Trachypogon sp. grasses

    NASA Astrophysics Data System (ADS)

    Sanhueza, E.; Donoso, L.

    2006-07-01

    Methane flux measurements from the soil-grass system were made during the wet season in unperturbed plots and plots where standing dry and green Trachypogon sp. grasses were clipped to just above the soil surface. Results support the surprising discovery that vegetation emits methane. The dry/green mixture of grasses produce methane at a rate of ~10 ng m-2 s-1, which extrapolated to the global savanna would produce an annual emission of ~5 Tg, much lower than the production recently suggested in the literature. On the other hand, during the wet season savanna soil consume CH4 at a rate of ~4.7 ng m-2 s-1, producing a global sink of ~1.3 Tg yr-1. Therefore, the tropical savanna soil-grass system would make a modest contribution to the global budget of methane.

  13. Eco-hydrology driven fire regime in savanna.

    PubMed

    Ursino, Nadia

    2014-08-21

    Fire is an important evolutionary force and ecosystem consumer that shapes savanna composition. However, ecologists have not comprehensively explained the functioning and maintenance of flammable savannas. A new minimal model accounting for the interdependence between soil saturation, biomass growth, fuel availability and fire has been used to predict the increasing tree density and fire frequency along a Mean Annual Rainfall (MAR) gradient for a typical savanna. Cyclic fire recurrence is reproduced using a predator prey approach in which fire is the "predator" and vegetation is the "prey". For the first time, fire frequency is not defined a priori but rather arises from the composition of vegetation, which determines fuel availability and water limitation. Soil aridity affects fuel production and fuel composition, thus indirectly affecting the ecosystem vulnerability to fire and fire frequency. The model demonstrates that two distinct eco-hydrological states correspond to different fire frequencies: (i) at low MAR, grass is abundant and the impact of fire on the environment is enhanced by the large fuel availability, (ii) at higher MAR, tree density progressively increases and provides less fuel for fire, leading to more frequent and less destructive fires, and (iii) the threshold MAR that determines the transition between the two states and the fire frequency at high MAR are affected by the vulnerability of trees to grass fire. The eco-hydrology-driven predator-prey model originally predicts that the transition between dry and wet savanna is characterized by a shift in wildfire frequency driven by major differences in soil moisture available for plants and savanna structure. The shift and the role of fire in conserving savanna ecosystems could not have been predicted if fire was considered as an external forcing rather than an intrinsic property of the ecosystem.

  14. Erosion and landscape development decouple strontium and sulfur in the transition to dominance by atmospheric inputs

    USGS Publications Warehouse

    Bern, C.R.; Porder, S.; Townsend, A.R.

    2007-01-01

    Weathering and leaching can progressively deplete the pools of soluble, rock-derived elements in soils and ecosystems over millennial time-scales, such that productivity increasingly relies on inputs from atmospheric deposition. This transition has been explored using strontium isotopes, which have been widely assumed to be a proxy for the provenance of other rock-derived elements. We compared rock versus atmospheric proportions of strontium to those for sulfur, a plant macronutrient, at several tropical forest sites in Hawaii and Costa Rica. Isotopic analyses reveal that sulfur is often decoupled from strontium in the transition to atmospheric dependence. Decoupling is likely the result of differences in chemical factors such as atmospheric input rates, mobility in the soil environment, and mineral weathering susceptibility. Strontium and sulfur decoupling appears to be accentuated by the physical process of erosion. Erosion rates are presumed to be high on the Osa Peninsula of Costa Rica, where the recent onset of rapid tectonic uplift has placed the landscape in a transient state. Decoupling is strong there, as erosion has rejuvenated the supply of rock-derived strontium but not sulfur. The landscape response to changes in tectonic uplift on the Osa Peninsula has produced decoupling at the landscape scale. Decoupling is more variable along a Hawaiian catena, presumably due to smaller scale variations in erosion rates and their influence on rejuvenation of rock-strontium inputs. These results illustrate how chemical and physical processes can interact to produce contrasting origins for different nutrient elements in soils and the ecosystems they support. ?? 2007 Elsevier B.V. All rights reserved.

  15. Phytolith analysis as a tool for palaeo-environmental studies: a case study of the reconstruction of the historical extent of oak savanna in the Willamette Valley, Oregon

    NASA Astrophysics Data System (ADS)

    Kirchholtes, Renske; van Mourik, Jan; Johnson, Bart

    2014-05-01

    Landscape-level restorations can be costly, so the effectiveness of the approach and the objectives of the restoration should be supported by a comprehensive investigation. The goal of the research presented here is to provide the basis for such a restoration effort using phytolith analyses. Fire suppression and loss of indigenous burning in the Willamette Valley, Oregon (USA) has led to near disappearance of the Oregon white oak savanna. Under suppressed fire regimes the shade-intolerant Garry oaks (Quercus garryana) are outcompeted by Douglas-fir (Pseudotsuga menziesii). As a consequence, the Oregon white oak savanna has been reduced to <5% of its former extent. This range contraction has had significant impacts on regional biodiversity due to habitat loss and fragmentation of the many savanna-dependent plant and animal species. Landscape-level restorations of oak savannas are needed to conserve biodiversity. Creating a more open landscape in which wildfires play a vital role, ties in with efforts to reduce fuel loads. Under a warming climate and changing precipitation patterns, reducing fire risk, fire intensity and fuel loading is critical. Frequent, low-intensity burning of both natural and Native American origin created open spaces in the otherwise densely forested hills and mountains of the Cascade Range. Thus, determining an appropriate "restoration point" (estimate of percent forest cover,) requires a pre-settlement paleoenvironmental reconstruction. However, the conventional indicators used in floristic reconstructions (pollen and spores) are seldom preserved in the dry, oxidized sediments of savannahs, meaning an alternative line of evidence is required for their historical study. Phytoliths are small yet robust silica particles produced by most plants. Many phytoliths take on cell shapes diagnostic of specific plant lineages, acting as indicators of their past presence. Unlike pollen grains, phytoliths readily preserve in well-drained soils during

  16. Seasonal Habitat Use by Greater Sage-Grouse (Centrocercus urophasianus) on a Landscape with Low Density Oil and Gas Development.

    PubMed

    Rice, Mindy B; Rossi, Liza G; Apa, Anthony D

    2016-01-01

    Fragmentation of the sagebrush (Artemisia spp.) ecosystem has led to concern about a variety of sagebrush obligates including the greater sage-grouse (Centrocercus urophasianus). Given the increase of energy development within greater sage-grouse habitats, mapping seasonal habitats in pre-development populations is critical. The North Park population in Colorado is one of the largest and most stable in the state and provides a unique case study for investigating resource selection at a relatively low level of energy development compared to other populations both within and outside the state. We used locations from 117 radio-marked female greater sage-grouse in North Park, Colorado to develop seasonal resource selection models. We then added energy development variables to the base models at both a landscape and local scale to determine if energy variables improved the fit of the seasonal models. The base models for breeding and winter resource selection predicted greater use in large expanses of sagebrush whereas the base summer model predicted greater use along the edge of riparian areas. Energy development variables did not improve the winter or the summer models at either scale of analysis, but distance to oil/gas roads slightly improved model fit at both scales in the breeding season, albeit in opposite ways. At the landscape scale, greater sage-grouse were closer to oil/gas roads whereas they were further from oil/gas roads at the local scale during the breeding season. Although we found limited effects from low level energy development in the breeding season, the scale of analysis can influence the interpretation of effects. The lack of strong effects from energy development may be indicative that energy development at current levels are not impacting greater sage-grouse in North Park. Our baseline seasonal resource selection maps can be used for conservation to help identify ways of minimizing the effects of energy development.

  17. Seasonal Habitat Use by Greater Sage-Grouse (Centrocercus urophasianus) on a Landscape with Low Density Oil and Gas Development

    PubMed Central

    2016-01-01

    Fragmentation of the sagebrush (Artemisia spp.) ecosystem has led to concern about a variety of sagebrush obligates including the greater sage-grouse (Centrocercus urophasianus). Given the increase of energy development within greater sage-grouse habitats, mapping seasonal habitats in pre-development populations is critical. The North Park population in Colorado is one of the largest and most stable in the state and provides a unique case study for investigating resource selection at a relatively low level of energy development compared to other populations both within and outside the state. We used locations from 117 radio-marked female greater sage-grouse in North Park, Colorado to develop seasonal resource selection models. We then added energy development variables to the base models at both a landscape and local scale to determine if energy variables improved the fit of the seasonal models. The base models for breeding and winter resource selection predicted greater use in large expanses of sagebrush whereas the base summer model predicted greater use along the edge of riparian areas. Energy development variables did not improve the winter or the summer models at either scale of analysis, but distance to oil/gas roads slightly improved model fit at both scales in the breeding season, albeit in opposite ways. At the landscape scale, greater sage-grouse were closer to oil/gas roads whereas they were further from oil/gas roads at the local scale during the breeding season. Although we found limited effects from low level energy development in the breeding season, the scale of analysis can influence the interpretation of effects. The lack of strong effects from energy development may be indicative that energy development at current levels are not impacting greater sage-grouse in North Park. Our baseline seasonal resource selection maps can be used for conservation to help identify ways of minimizing the effects of energy development. PMID:27788202

  18. Climatic changes can drive the loss of genetic diversity in a Neotropical savanna tree species.

    PubMed

    Lima, Jacqueline S; Ballesteros-Mejia, Liliana; Lima-Ribeiro, Matheus S; Collevatti, Rosane G

    2017-03-13

    The high rates of future climatic changes, compared with the rates reported for past changes, may hamper species adaptation to new climates or the tracking of suitable conditions, resulting in significant loss of genetic diversity. Trees are dominant species in many biomes and because they are long-lived, they may not be able to cope with ongoing climatic changes. Here, we coupled Ecological Niche Modelling (ENM) and genetic simulations to forecast the effects of climatic changes on the genetic diversity and the structure of genetic clusters. Genetic simulations were conditioned to climatic variables and restricted to plant dispersal and establishment. We used a Neotropical savanna tree as species model that shows a preference for hot and drier climates, but with low temperature seasonality. The ENM predicts a decreasing range size along the more severe future climatic scenario. Additionally, genetic diversity and allelic richness also decrease with range retraction and climatic genetic clusters are lost for both future scenarios, which will lead genetic variability to homogenize throughout the landscape. Besides, climatic genetic clusters will spatially reconfigure on the landscape following displacements of climatic conditions. Our findings indicate that climate change effects will challenge population adaptation to new environmental conditions because of the displacement of genetic ancestry clusters from their optimal conditions. This article is protected by copyright. All rights reserved.

  19. Multiple ecosystem services in a working landscape

    PubMed Central

    Eastburn, Danny J.; O’Geen, Anthony T.; Tate, Kenneth W.; Roche, Leslie M.

    2017-01-01

    Policy makers and practitioners are in need of useful tools and models for assessing ecosystem service outcomes and the potential risks and opportunities of ecosystem management options. We utilize a state-and-transition model framework integrating dynamic soil and vegetation properties to examine multiple ecosystem services—specifically agricultural production, biodiversity and habitat, and soil health—across human created vegetation states in a managed oak woodland landscape in a Mediterranean climate. We found clear tradeoffs and synergies in management outcomes. Grassland states maximized agricultural productivity at a loss of soil health, biodiversity, and other ecosystem services. Synergies existed among multiple ecosystem services in savanna and woodland states with significantly larger nutrient pools, more diversity and native plant richness, and less invasive species. This integrative approach can be adapted to a diversity of working landscapes to provide useful information for science-based ecosystem service valuations, conservation decision making, and management effectiveness assessments. PMID:28301475

  20. Multiple ecosystem services in a working landscape.

    PubMed

    Eastburn, Danny J; O'Geen, Anthony T; Tate, Kenneth W; Roche, Leslie M

    2017-01-01

    Policy makers and practitioners are in need of useful tools and models for assessing ecosystem service outcomes and the potential risks and opportunities of ecosystem management options. We utilize a state-and-transition model framework integrating dynamic soil and vegetation properties to examine multiple ecosystem services-specifically agricultural production, biodiversity and habitat, and soil health-across human created vegetation states in a managed oak woodland landscape in a Mediterranean climate. We found clear tradeoffs and synergies in management outcomes. Grassland states maximized agricultural productivity at a loss of soil health, biodiversity, and other ecosystem services. Synergies existed among multiple ecosystem services in savanna and woodland states with significantly larger nutrient pools, more diversity and native plant richness, and less invasive species. This integrative approach can be adapted to a diversity of working landscapes to provide useful information for science-based ecosystem service valuations, conservation decision making, and management effectiveness assessments.

  1. Oil and Gas Development in Southwestern Wyoming - Energy Data and Services for the Wyoming Landscape Conservation Initiative (WLCI)

    USGS Publications Warehouse

    Biewick, Laura R.H.

    2009-01-01

    The purpose of this report is to explore current oil and gas energy development in the area encompassing the Wyoming Landscape Conservation Initiative. The Wyoming Landscape Conservation Initiative is a long-term science-based effort to ensure southwestern Wyoming's wildlife and habitat remain viable in areas facing development pressure. Wyoming encompasses some of the highest quality wildlife habitats in the Intermountain West. At the same time, this region is an important source of natural gas. Using Geographic Information System technology, energy data pertinent to the conservation decision-making process have been assembled to show historical oil and gas exploration and production in southwestern Wyoming. In addition to historical data, estimates of undiscovered oil and gas are included from the 2002 U.S. Geological Survey National Assessment of Oil and Gas in the Southwestern Wyoming Province. This report is meant to facilitate the integration of existing data with new knowledge and technologies to analyze energy resources development and to assist in habitat conservation planning. The well and assessment data can be accessed and shared among many different clients including, but not limited to, an online web-service for scientists and resource managers engaged in the Initiative.

  2. Development of a Remotely-sensed Soil Heat Flux Parameterization for Natural Landscapes in Semi-arid Regions

    NASA Astrophysics Data System (ADS)

    Kim, J.; Scott, R.; Hogue, T.

    2007-12-01

    Due to the difficulties in directly measuring soil heat flux (G), research on empirical estimation has moved toward use of a strong association between soil heat flux and net radiation (Rnet). The majority of these studies are concentrated on the estimation of soil heat flux from mature agricultural areas in semi-arid regions due to the high demand for irrigation water. However, natural land surfaces, the largest fraction of semi-arid and arid regions, have not been well studied with regards to soil heat flux estimation. Therefore, application of the previously developed empirical equations to natural land surfaces results in large uncertainty in soil heat flux estimates. This study explores development of an empirical relationship that is well-suited for natural landscapes within semi-arid areas in order to provide a more thorough assessment of regional evaporation (i.e. water consumption) in water-limited regions. Particularly, we seek to develop an empirical relationship between soil heat flux and net radiation when observations from the mid-day polar orbiting satellites (i.e. Terra/Aqua) are available. MODIS-derived components such as vegetation indices, albedo and surface temperature are being used to characterize this relationship over a set of flux tower sites in southern Arizona. Evaluation of existing soil heat flux schemes as well as results from validation of a new formulation suitable for use in natural landscapes within semi-arid regions will be presented.

  3. Effects of tree harvest on the stable-state dynamics of savanna and forest.

    PubMed

    Tredennick, Andrew T; Hanan, Niall P

    2015-05-01

    Contemporary theory on the maintenance and stability of the savanna biome has focused extensively on how climate and disturbances interact to affect tree growth and demography. In particular, the role of fire in reducing tree cover from climatic maxima is now well appreciated, and in certain cases, herbivory also strongly affects tree cover. However, in African savannas and forests, harvest of trees by humans for cooking and heating is an oft overlooked disturbance. Thus, we incorporate tree harvest into a population dynamic model of grasses, savanna saplings, savanna trees, and forest trees. We use assumptions about the differential demographic responses of savanna trees and forest trees to harvest to show how tree harvest influences tree cover, demography, and community composition. Tree harvest can erode the intrinsic basin of attraction for forest and make a state transition via fire to savanna more likely. The savanna state is generally resilient to all but high levels of tree harvest because of the resprouting abilities of savanna trees. In the absence of active fire suppression, our analysis suggests that we can expect to see large and potentially irreversible shifts from forest to savanna as demand increases for charcoal in sub-Saharan Africa. On the other hand, savanna tree species' traits promote savanna stability in the face of low to moderate harvest pressure.

  4. Indirect effects of domestic and wild herbivores on butterflies in an African savanna

    PubMed Central

    Wilkerson, Marit L; Roche, Leslie M; Young, Truman P

    2013-01-01

    Indirect interactions driven by livestock and wild herbivores are increasingly recognized as important aspects of community dynamics in savannas and rangelands. Large ungulate herbivores can both directly and indirectly impact the reproductive structures of plants, which in turn can affect the pollinators of those plants. We examined how wild herbivores and cattle each indirectly affect the abundance of a common pollinator butterfly taxon, Colotis spp., at a set of long-term, large herbivore exclosure plots in a semiarid savanna in central Kenya. We also examined effects of herbivore exclusion on the main food plant of Colotis spp., which was also the most common flowering species in our plots: the shrub Cadaba farinosa. The study was conducted in four types of experimental plots: cattle-only, wildlife-only, cattle and wildlife (all large herbivores), and no large herbivores. Across all plots, Colotis spp. abundances were positively correlated with both Cadaba flower numbers (adult food resources) and total Cadaba canopy area (larval food resources). Structural equation modeling (SEM) revealed that floral resources drove the abundance of Colotis butterflies. Excluding browsing wildlife increased the abundances of both Cadaba flowers and Colotis butterflies. However, flower numbers and Colotis spp. abundances were greater in plots with cattle herbivory than in plots that excluded all large herbivores. Our results suggest that wild browsing herbivores can suppress pollinator species whereas well-managed cattle use may benefit important pollinators and the plants that depend on them. This study documents a novel set of ecological interactions that demonstrate how both conservation and livelihood goals can be met in a working landscape with abundant wildlife and livestock. PMID:24198932

  5. Fuels and fire behavior dynamics on large-scale savanna fires in Kruger National Park, South Africa

    NASA Astrophysics Data System (ADS)

    Stocks, B. J.; van Wilgen, B. W.; Trollope, W. S. W.; McRae, D. J.; Mason, J. A.; Weirich, F.; Potgieter, A. L. F.

    1996-10-01

    Biomass characterization and fire behavior documentation were carried out on two large (>2000 ha) experimental fires conducted in arid savanna fuels in Kruger National Park in September 1992. Prefire fuel loads, fuel consumption, spread rates, flame zone characteristics, and in-fire and perimeter wind field dynamics were measured in order to determine overall energy release rates for each fire. Convection column dynamics were also measured in support of airborne trace gas and particulate measurements. Energy release rates varied significantly between the two fires, and this was strongly reflected in convection column development. The lower-intensity fire produced a weak, poorly defined smoke plume, while a well-developed column with a capping cumulus top developed during the higher intensity fire. Further experimental burning studies, in savannas with higher fuel loads, are recommended to further explore the fire behavior-convection column dynamics relationship investigated in this study.

  6. Post-Gondwana geomorphic evolution of southwestern Africa: Implications for hte controls on landscape development from observations and numerical experiments

    NASA Technical Reports Server (NTRS)

    Gilchrist, Alan R.; Kooi, Henk; Beaumont, Christopher

    1994-01-01

    The relationship between morphology and surficial geology is used to quantify the denudation that has occurred across southwestern Africa sicne the fragmentation of Gondwana during the Early Mesozoic. Two main points emerge. Signficant denudation, of the order of kilometers, is widespread except in the Kalahari region of the continental interior. The denudation is systematically distributed so that the continental exterior catchment, draining directly to the Cape basin, is denuded to a greater depth than the interior catchment inland of the Great Escarpment. The analysis also implies tha the majority of the denudation occurred before the beginning of the Cenozoic for both teh exerior and interior catchments. Existing models of landscape development are reviewed, and implications of the denudation chronology are incorporated into a revised conceptual model. This revision implies tha thte primary effect of rifting on the subsequent landscape evolution is that it generates two distinct drainage regimes. A marginal upwarp, or rift flank uplift, separates rejuvenated rivers that drain into the subsiding rift from rivers in the continetal interior that are deflected but not rejuvenated. The two catchments evolve independently unless they are integrated by breaching of hte marginal upwarp. If this occurs, the exterior baselevel is communicated to the interior catchment that is denuded accordingly. Denudation rates generally decrease as the margin evolves, and this decrease is reinforced by the exposure of substrate that is resistant to denudation and/or a change to a more arid climate. The observations do not reveal a particular style of smaller-scale landscape evolution, sucha s escarpment retreat, that is responsible for the differential denudation across the region. It is proposed that numerical model experiments, which reflect the observational insights at the large scale, may identify the smaller-scale controls on escarpment development if the model and natural

  7. Post-Gondwana geomorphic evolution of southwestern Africa: Implications for hte controls on landscape development from observations and numerical experiments

    NASA Technical Reports Server (NTRS)

    Gilchrist, Alan R.; Kooi, Henk; Beaumont, Christopher

    1994-01-01

    The relationship between morphology and surficial geology is used to quantify the denudation that has occurred across southwestern Africa sicne the fragmentation of Gondwana during the Early Mesozoic. Two main points emerge. Signficant denudation, of the order of kilometers, is widespread except in the Kalahari region of the continental interior. The denudation is systematically distributed so that the continental exterior catchment, draining directly to the Cape basin, is denuded to a greater depth than the interior catchment inland of the Great Escarpment. The analysis also implies tha the majority of the denudation occurred before the beginning of the Cenozoic for both teh exerior and interior catchments. Existing models of landscape development are reviewed, and implications of the denudation chronology are incorporated into a revised conceptual model. This revision implies tha thte primary effect of rifting on the subsequent landscape evolution is that it generates two distinct drainage regimes. A marginal upwarp, or rift flank uplift, separates rejuvenated rivers that drain into the subsiding rift from rivers in the continetal interior that are deflected but not rejuvenated. The two catchments evolve independently unless they are integrated by breaching of hte marginal upwarp. If this occurs, the exterior baselevel is communicated to the interior catchment that is denuded accordingly. Denudation rates generally decrease as the margin evolves, and this decrease is reinforced by the exposure of substrate that is resistant to denudation and/or a change to a more arid climate. The observations do not reveal a particular style of smaller-scale landscape evolution, sucha s escarpment retreat, that is responsible for the differential denudation across the region. It is proposed that numerical model experiments, which reflect the observational insights at the large scale, may identify the smaller-scale controls on escarpment development if the model and natural

  8. Landscape alterations influence differential habitat use of nesting buteos and ravens within sagebrush ecosystem: implications for transmission line development

    USGS Publications Warehouse

    Coates, Peter S.; Howe, Kristy B.; Casazza, Michael L.; Delehanty, David J.

    2014-01-01

    A goal in avian ecology is to understand factors that influence differences in nesting habitat and distribution among species, especially within changing landscapes. Over the past 2 decades, humans have altered sagebrush ecosystems as a result of expansion in energy production and transmission. Our primary study objective was to identify differences in the use of landscape characteristics and natural and anthropogenic features by nesting Common Ravens (Corvus corax) and 3 species of buteo (Swainson's Hawk [Buteo swainsoni], Red-tailed Hawk [B. jamaicensis], and Ferruginous Hawk [B. regalis]) within a sagebrush ecosystem in southeastern Idaho. During 2007–2009, we measured multiple environmental factors associated with 212 nest sites using data collected remotely and in the field. We then developed multinomial models to predict nesting probabilities by each species and predictive response curves based on model-averaged estimates. We found differences among species related to nesting substrate (natural vs. anthropogenic), agriculture, native grassland, and edge (interface of 2 cover types). Most important, ravens had a higher probability of nesting on anthropogenic features (0.80) than the other 3 species (Artemisia spp.), favoring increased numbers of nesting ravens and fewer nesting Ferruginous Hawks. Our results indicate that habitat alterations, fragmentation, and forthcoming disturbances anticipated with continued energy development in sagebrush steppe ecosystems can lead to predictable changes in raptor and raven communities.

  9. A New Application to Facilitate Post-Fire Recovery and Rehabilitation in Savanna Ecosystems

    NASA Technical Reports Server (NTRS)

    Carroll, Mark L.; Schnase, John L.; Weber, Keith T.; Brown, Molly E.; Gill, Roger L.; Haskett, George W.; Gardner, Tess A.

    2013-01-01

    The U.S. government spends an estimated $3billion per year to fight forest fires in the United States. Post-fire rehabilitation activities represent a small but essential portion of that total. The Rehabilitation Capability Convergence for Ecosystem Recovery (RECOVER) system is currently under development for Savanna ecosystems in the western U.S. The prototype of this system has been built and will have realworld testing during the summer 2013 fire season. When fully deployed, the RECOVER system will provide the emergency rehabilitation teams with critical and timely information for management decisions regarding stabilization and rehabilitation strategies.

  10. Seasonal changes of water carbon relations in savanna ecosystems

    NASA Astrophysics Data System (ADS)

    Kutsch, W. L.; Merbold, L.; Archibald, S.

    2011-12-01

    During evolution plant species have developed different strategies to optimize the water carbon relations. These stratgies summarize to ecosystem properties. As an example we show how tropical and subtropical savannas and woodlands can respond flexibly to changes in temperature and water availability and thus optimize carbon and water fluxes between land surface and atmosphere. Several phenomena are presented and discussed in this overview from African flux sites in Zambia, Burkina Faso and South Africa: Pre-rain leaf development: Many trees developed new leaves before the first rain appeared. As a consequence of this early timing of leaf flush, the phenological increase of photosynthetic capacity (Amax) was steeper than in temperate forests. Mid-term response of conductance and photosynthesis to soil water relations: The regulation of canopy conductance was temporally changing in two ways: changes due to phenology during the course of the growing season and short-term (hours to days) acclimation to soil water conditions. The most constant parameter was water use efficiency. It was influenced by water vapour pressure deficit (VPD) during the day, but the VPD response curve of water usage only changed slightly during the course of the growing season, and decreased by about 30% during the transition from wet to dry season. The regulation of canopy conductance and photosynthetic capacity were closely related. This observation meets recent leaf-level findings that stomatal closure triggers down-regulation of Rubisco during drought. Our results may show the effects of these processes on the ecosystem scale. Furthermore, we observed that the close relationship between stomatal conductance and photosynthesis resulted in different temperature optima of GPP that were close to the average daytime temperature. Adaptation of respiration to rain pulses: Finally, the response of respiration to rain pulses showed changes throughout the growing season. The first rain events early

  11. Developing Aesthetically Compelling Visualizations for Documenting and Communicating Alaskan Glacier and Landscape Change

    NASA Astrophysics Data System (ADS)

    Molnia, B. F.

    2016-12-01

    For 50 years I have investigated glacier dynamics and attempted to convey this information to others. Since 2000, my focus has been on capturing and documenting decadal and century-scale Alaskan glacier and landscape change using precision repeat photography and on broadly communicate these results through simple, aesthetically compelling, unambiguous visualizations. As a young geologist, I spent the summer of 1968 on the Juneau Icefield, photographing its surface features and margins. Since then, I have taken 150,000 photographs of Alaskan glaciers and collected 5,000 historical Alaskan photographs taken by other, the earliest dating back to 1883. This database and my passion for photographing glaciers became the basis for an on-going investigation aimed at visually documenting glacier and landscapes change at more than 200 previously photographed Alaskan locations in Glacier Bay and Kenai Fjords National Parks, Prince William Sound, and the Coast Mountains. Repeat photography is a technique in which a historical and a modern photograph, both having similar fields of view, are compared and contrasted to quantitatively and qualitatively determine their similarities and differences. In precision repeat photography, both photographs have the same field of view, ideally being photographed from the identical location. Since 2000, I have conducted nearly 20 field campaigns to systematically revisit and re-photograph more than 225 fields of view previously captured in the historical photographs. As aesthetics are important in successfully communicating what has changed, substantial time and effort is invested in capturing new, comparable, generally cloud free photographs at each revisited site. The resulting modern images are then paired with similar field-of-view historical images to produce compelling, aesthetic photo pairs which depict long-term glacier, landscape, and ecosystem changes. As a few sites have multiple historical images, photo triplets or quadruplets are

  12. Restoring a disappearing ecosystem: the longleaf pine savanna

    Treesearch

    Tim Harrington; Karl Miller; Noreen. Parks

    2013-01-01

    Longleaf pine (Pinus palustris) savannas of the southeastern United States contain some of the world’s most diverse plant communities, along with a unique complement of wildlife. Their traditionally open canopy structure and rich understory of grasses and herbs were critical to their vigor. However, a long history of land-use practices such as...

  13. Restoring a disappearing ecosystem: the Longleaf Pine Savanna.

    SciTech Connect

    Harrington, Timothy B.; Miller, Karl V.; Park, Noreen

    2013-05-01

    Longleaf pine (Pinus palustris) savannas of the southeastern United States contain some of the worlds most diverse plant communities, along with a unique complement of wildlife. Their traditionally open canopy structure and rich understory of grasses and herbs were critical to their vigor. However, a long history of land-use practices such as logging, farming, and fire exclusion have reduced this once-widespread ecosystem to only 3 percent of its original range. At six longleaf pine plantations in South Carolina, Tim Harrington with the Pacific Northwest Research Station and collaborators with the Southern Research Station used various treatments (including prescribed burns, tree thinning, and herbicide applications) to alter the forest structure and tracked how successful each one was in advancing savanna restoration over a 14-year period. They found that typical planting densities for wood production in plantations create dense understory shade that excludes many native herbaceous species important to savannas and associated wildlife. The scientists found that although tree thinning alone did not result in sustained gains, a combination of controlled burning, thinning, and herbicide treatments to reduce woody plants was an effective strategy for recovering the savanna ecosystem. The scientists also found that these efforts must be repeated periodically for enduring benefits.

  14. Community-Based Ecological Restoration: The Wingra Oak Savanna Project.

    ERIC Educational Resources Information Center

    Bader, Brian J.; Egan, Dave

    1999-01-01

    The University of Wisconsin-Madison Arboretum, a pioneer in ecological restoration, is involving the local community in restoring a site to its presettlement condition as an oak savanna. Besides providing the manual labor of restoration, volunteers learn about the land and the ecological processes that tie nature and culture together. A 60-hour…

  15. Hydraulic redistribution of soil water by neotropical savanna trees.

    Treesearch

    Fabian G. Scholz; Sandra J. Bucci; Guillermo Goldstein; et al.

    2002-01-01

    The magnitude and direction of water transport by the roots of eight dominant Brazilian savanna (Cerrado) allowed bidirectional measurements of sap flow. The patterns of sap flow observed during the dry season in species with dimorphic roots systems were consistent with the occurrence of hydraulic redistribution of soil water, the movement of water from moist to drier...

  16. Restoration of temperate savannas and woodlands [Chapter 11

    Treesearch

    Brice B. Hanberry; John M. Kabrick; Peter W. Dunwiddie; Tibor Hartel; Theresa B. Jain; Benjamin O. Knapp

    2017-01-01

    Savannas and woodlands are open forest phases that occur along a gradient between grasslands and closed canopy forests. These ecosystems are characterized by open to nearly closed canopies of overstorey trees, relatively sparse midstorey and understorey woody vegetation, and dense, species-rich ground flora. In contrast to closed forests, the dominant and codominant...

  17. Nitrogen deposition in tropical forests from deforestation and savanna fires

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Randerson, J. T.; van der Werf, G.; Morton, D. C.; Kasibhatla, P. S.

    2009-12-01

    Tropical forests account for nearly half of global net primary production (NPP) and may contribute substantially to contemporary and future land carbon (C) sinks. We used satellite-derived estimates of global fire emissions and a chemical transport model to estimate atmospheric nitrogen (N) fluxes from deforestation and savanna fires in tropical ecosystems. N emissions and deposition led to a substantial net transport of N equatorward, from savannas and areas undergoing deforestation to tropical forests. On average, N emissions from fires were equivalent to approximately 28% of biological N fixation (BNF) in savannas (4.8 kg N ha-1 yr-1) and 38% of BNF from ecosystems at the deforestation frontier (9.1 kg N ha-1 yr-1). N deposition occurred in interior tropical forests at a rate equivalent to 4% of their BNF (1.1 kg N ha-1 yr-1). This percentage was highest for African tropical forests in the Congo Basin (16%; 3.7 kg N ha-1 yr-1) owing to equatorward transport from northern and southern savannas. These results suggest that land use change, including deforestation fires, may be enhancing nutrient availability and carbon sequestration in nearby tropical forest ecosystems.

  18. Community-Based Ecological Restoration: The Wingra Oak Savanna Project.

    ERIC Educational Resources Information Center

    Bader, Brian J.; Egan, Dave

    1999-01-01

    The University of Wisconsin-Madison Arboretum, a pioneer in ecological restoration, is involving the local community in restoring a site to its presettlement condition as an oak savanna. Besides providing the manual labor of restoration, volunteers learn about the land and the ecological processes that tie nature and culture together. A 60-hour…

  19. Soil microbial communities following bush removal in a Namibian savanna

    USDA-ARS?s Scientific Manuscript database

    Savanna ecosystems are subject to desertification and bush encroachment, which reduce the grazing value of the land and hence the carrying capacity for wildlife and livestock. In this study we examined the soil microbial communities under bush and grass in Namibia. We analyzed the soil at a chronose...

  20. Contrasting long-term records of biomass burning in wet and dry savannas of equatorial East Africa.

    PubMed

    Colombaroli, Daniele; Ssemmanda, Immaculate; Gelorini, Vanessa; Verschuren, Dirk

    2014-09-01

    Rainfall controls fire in tropical savanna ecosystems through impacting both the amount and flammability of plant biomass, and consequently, predicted changes in tropical precipitation over the next century are likely to have contrasting effects on the fire regimes of wet and dry savannas. We reconstructed the long-term dynamics of biomass burning in equatorial East Africa, using fossil charcoal particles from two well-dated lake-sediment records in western Uganda and central Kenya. We compared these high-resolution (5 years/sample) time series of biomass burning, spanning the last 3800 and 1200 years, with independent data on past hydroclimatic variability and vegetation dynamics. In western Uganda, a rapid (<100 years) and permanent increase in burning occurred around 2170 years ago, when climatic drying replaced semideciduous forest by wooded grassland. At the century time scale, biomass burning was inversely related to moisture balance for much of the next two millennia until ca. 1750 ad, when burning increased strongly despite regional climate becoming wetter. A sustained decrease in burning since the mid20th century reflects the intensified modern-day landscape conversion into cropland and plantations. In contrast, in semiarid central Kenya, biomass burning peaked at intermediate moisture-balance levels, whereas it was lower both during the wettest and driest multidecadal periods of the last 1200 years. Here, burning steadily increased since the mid20th century, presumably due to more frequent deliberate ignitions for bush clearing and cattle ranching. Both the observed historical trends and regional contrasts in biomass burning are consistent with spatial variability in fire regimes across the African savanna biome today. They demonstrate the strong dependence of East African fire regimes on both climatic moisture balance and vegetation, and the extent to which this dependence is now being overridden by anthropogenic activity. © 2014 John Wiley & Sons Ltd.

  1. Wavelet-based detection of bush encroachment in a savanna using multi-temporal aerial photographs and satellite imagery

    NASA Astrophysics Data System (ADS)

    Shekede, Munyaradzi D.; Murwira, Amon; Masocha, Mhosisi

    2015-03-01

    Although increased woody plant abundance has been reported in tropical savannas worldwide, techniques for detecting the direction and magnitude of change are mostly based on visual interpretation of historical aerial photography or textural analysis of multi-temporal satellite images. These techniques are prone to human error and do not permit integration of remotely sensed data from diverse sources. Here, we integrate aerial photographs with high spatial resolution satellite imagery and use a discrete wavelet transform to objectively detect the dynamics in bush encroachment at two protected Zimbabwean savanna sites. Based on the recently introduced intensity-dominant scale approach, we test the hypotheses that: (1) the encroachment of woody patches into the surrounding grassland matrix causes a shift in the dominant scale. This shift in the dominant scale can be detected using a discrete wavelet transform regardless of whether aerial photography and satellite data are used; and (2) as the woody patch size stabilises, woody cover tends to increase thereby triggering changes in intensity. The results show that at the first site where tree patches were already established (Lake Chivero Game Reserve), between 1972 and 1984 the dominant scale of woody patches initially increased from 8 m before stabilising at 16 m and 32 m between 1984 and 2012 while the intensity fluctuated during the same period. In contrast, at the second site, which was formely grass-dominated site (Kyle Game Reserve), we observed an unclear dominant scale (1972) which later becomes distinct in 1985, 1996 and 2012. Over the same period, the intensity increased. Our results imply that using our approach we can detect and quantify woody/bush patch dynamics in savanna landscapes.

  2. Development of Sustainable Landscape Designs for Improved Biomass Production in the U.S. Corn Belt

    NASA Astrophysics Data System (ADS)

    Bonner, Ian J.

    Demand for renewable and sustainable energy options has resulted in a significant commitment by the US Government to research pathways for fuel production from biomass. The research presented in this thesis describes one potential pathway to increase the amount of biomass available for biofuel production by integrating dedicated energy crops into agricultural fields. In the first chapter an innovative landscape design method based on subfield placement of an energy crop into row crop fields in central Iowa is used to reduce financial loss for farmers, increase and diversify biomass production, and improve soil resources. The second chapter explores how subfield management decisions may be made using high fidelity data and modeling to balance concerns of primary crop production and economics. This work provides critical forward looking support to agricultural land managers and stakeholders in the biomass and bioenergy industry for pathways to improving land stewardship and energy security.

  3. Landscape development under human influence - a case study from the low mountain range Spessart

    NASA Astrophysics Data System (ADS)

    Kranz, Annegret; Bork, Hans-Rudolf; Nelle, Oliver; Müller, Ulrich; Fuchs, Markus; Fülling, Alexander

    2010-05-01

    Little is known about human settlement in prehistoric times in the low mountain ranges in central Germany. One of these ranges, the Spessart mountains, are known from written sources of the 1850s to have been a very poor area, where people suffered from starvation and numerous diseases. New interdisciplinary research in one catchment provides evidence that the region has first been settled during Neolithic times and provided a much higher soil fertility until early / high medieval times. Soil erosion due to extreme rainfall events and agricultural land use removed the thin fertile loess cover from the slopes of the catchment combined with gully incision. At the intersection of the catchment fan and the alluvial plain of the Elsava River, a high to late medieval archaeological moated site was excavated in 2008 and 2009. Detailed stratigraphy of the sediments in the moat enabled an environmental reconstruction of the area and in particular showed the beginnings of instability within the catchment. This instability continued presumably until ~ 1900 AD, and this persistence was caused by different land use techniques that could be reconstructed from various geomorphological features. Initial results indicate a rotating wood - pasture - agriculture cultivation system that was used within the catchment on slopes with a north west aspect. The intense charcoal production associated with this cultivation system enables anthracological investigations which provides the opportunity for reconstruction of the vegetation composition on a local scale at a high temporal and spatial resolution. This is then combined with paleobotanical macro remains and pollen analysis to enable a comprehensive palaeoenvironmental context for this poorly studied archaeological landscape. By quantifiying sediment flux, these landscape reconstruction results provide a foundation for archaeological and geomorphological research in a wider context throughout central Germany.

  4. Planetary Landscape Geography

    NASA Astrophysics Data System (ADS)

    Hargitai, H.

    INTRODUCTION Landscape is one of the most often used category in physical ge- ography. The term "landshap" was introduced by Dutch painters in the 15-16th cen- tury. [1] The elements that build up a landscape (or environment) on Earth consists of natural (biogenic and abiogenic - lithologic, atmospheric, hydrologic) and artificial (antropogenic) factors. Landscape is a complex system of these different elements. The same lithology makes different landscapes under different climatic conditions. If the same conditions are present, the same landscape type will appear. Landscapes build up a hierarchic system and cover the whole surface. On Earth, landscapes can be classified and qualified according to their characteristics: relief forms (morphology), and its potential economic value. Aesthetic and subjective parameters can also be considered. Using the data from landers and data from orbiters we can now classify planetary landscapes (these can be used as geologic mapping units as well). By looking at a unknown landscape, we can determine the processes that created it and its development history. This was the case in the Pathfinder/Sojourner panoramas. [2]. DISCUSSION Planetary landscape evolution. We can draw a raw landscape develop- ment history by adding the different landscape building elements to each other. This has a strong connection with the planet's thermal evolution (age of the planet or the present surface materials) and with orbital parameters (distance from the central star, orbit excentricity etc). This way we can build a complex system in which we use differ- ent evolutional stages of lithologic, atmospheric, hydrologic and biogenic conditions which determine the given - Solar System or exoplanetary - landscape. Landscape elements. "Simple" landscapes can be found on asteroids: no linear horizon is present (not differentiated body, only impact structures), no atmosphere (therefore no atmospheric scattering - black sky as part of the landscape) and no

  5. [Landscape and ecological genomics].

    PubMed

    Tetushkin, E Ia

    2013-10-01

    Landscape genomics is the modern version of landscape genetics, a discipline that arose approximately 10 years ago as a combination of population genetics, landscape ecology, and spatial statistics. It studies the effects of environmental variables on gene flow and other microevolutionary processes that determine genetic connectivity and variations in populations. In contrast to population genetics, it operates at the level of individual specimens rather than at the level of population samples. Another important difference between landscape genetics and genomics and population genetics is that, in the former, the analysis of gene flow and local adaptations takes quantitative account of landforms and features of the matrix, i.e., hostile spaces that separate species habitats. Landscape genomics is a part of population ecogenomics, which, along with community genomics, is a major part of ecological genomics. One of the principal purposes of landscape genomics is the identification and differentiation of various genome-wide and locus-specific effects. The approaches and computation tools developed for combined analysis of genomic and landscape variables make it possible to detect adaptation-related genome fragments, which facilitates the planning of conservation efforts and the prediction of species' fate in response to expected changes in the environment.

  6. Projected changes in distributions of Australian tropical savanna birds under climate change using three dispersal scenarios.

    PubMed

    Reside, April E; Vanderwal, Jeremy; Kutt, Alex S

    2012-04-01

    Identifying the species most vulnerable to extinction as a result of climate change is a necessary first step in mitigating biodiversity decline. Species distribution modeling (SDM) is a commonly used tool to assess potential climate change impacts on distributions of species. We use SDMs to predict geographic ranges for 243 birds of Australian tropical savannas, and to project changes in species richness and ranges under a future climate scenario between 1990 and 2080. Realistic predictions require recognition of the variability in species capacity to track climatically suitable environments. Here we assess the effect of dispersal on model results by using three approaches: full dispersal, no dispersal and a partial-dispersal scenario permitting species to track climate change at a rate of 30 km per decade. As expected, the projected distributions and richness patterns are highly sensitive to the dispersal scenario. Projected future range sizes decreased for 66% of species if full dispersal was assumed, but for 89% of species when no dispersal was assumed. However, realistic future predictions should not assume a single dispersal scenario for all species and as such, we assigned each species to the most appropriate dispersal category based on individual mobility and habitat specificity; this permitted the best estimates of where species will be in the future. Under this "realistic" dispersal scenario, projected ranges sizes decreased for 67% of species but showed that migratory and tropical-endemic birds are predicted to benefit from climate change with increasing distributional area. Richness hotspots of tropical savanna birds are expected to move, increasing in southern savannas and southward along the east coast of Australia, but decreasing in the arid zone. Understanding the complexity of effects of climate change on species' range sizes by incorporating dispersal capacities is a crucial step toward developing adaptation policies for the conservation of

  7. Projected changes in distributions of Australian tropical savanna birds under climate change using three dispersal scenarios

    PubMed Central

    Reside, April E; VanDerWal, Jeremy; Kutt, Alex S

    2012-01-01

    Identifying the species most vulnerable to extinction as a result of climate change is a necessary first step in mitigating biodiversity decline. Species distribution modeling (SDM) is a commonly used tool to assess potential climate change impacts on distributions of species. We use SDMs to predict geographic ranges for 243 birds of Australian tropical savannas, and to project changes in species richness and ranges under a future climate scenario between 1990 and 2080. Realistic predictions require recognition of the variability in species capacity to track climatically suitable environments. Here we assess the effect of dispersal on model results by using three approaches: full dispersal, no dispersal and a partial-dispersal scenario permitting species to track climate change at a rate of 30 km per decade. As expected, the projected distributions and richness patterns are highly sensitive to the dispersal scenario. Projected future range sizes decreased for 66% of species if full dispersal was assumed, but for 89% of species when no dispersal was assumed. However, realistic future predictions should not assume a single dispersal scenario for all species and as such, we assigned each species to the most appropriate dispersal category based on individual mobility and habitat specificity; this permitted the best estimates of where species will be in the future. Under this “realistic” dispersal scenario, projected ranges sizes decreased for 67% of species but showed that migratory and tropical-endemic birds are predicted to benefit from climate change with increasing distributional area. Richness hotspots of tropical savanna birds are expected to move, increasing in southern savannas and southward along the east coast of Australia, but decreasing in the arid zone. Understanding the complexity of effects of climate change on species’ range sizes by incorporating dispersal capacities is a crucial step toward developing adaptation policies for the conservation of

  8. Effects of controlled fire and livestock grazing on bird communities in East African savannas.

    PubMed

    Gregory, Nathan C; Sensenig, Ryan L; Wilcove, David S

    2010-12-01

    In East Africa fire and grazing by wild and domestic ungulates maintain savannas, and pastoralists historically set fires and herded livestock through the use of temporary corrals called bomas. In recent decades traditional pastoral practices have declined, and this may be affecting biodiversity. We investigated the effects of prescribed fires and bomas on savanna bird communities in East Africa during the first and second dry seasons of the year (respectively before and after the rains that mark the onset of breeding for most birds). We compared abundance, richness, and community composition on 9-ha burned plots, recently abandoned bomas, and control plots in the undisturbed matrix habitat over a 3-year period. Generally, recently burned areas and abandoned bomas attracted greater densities of birds and had different community assemblages than the surrounding matrix. The effects of disturbances were influenced by interactions between primary productivity, represented by the normalized difference vegetation index, and time. Bird densities were highest and a greater proportion of species was observed on burned plots in the months following the fires. Drought conditions equalized bird densities across treatments within 1 year, and individuals from a greater proportion of species were more commonly observed on abandoned bomas. Yearly fluctuations in abundance were less pronounced on bomas than on burns, which indicate that although fire may benefit birds in the short term, bomas may have a more-lasting positive effect and provide resources during droughts. Several Palearctic migrants were attracted to burned plots regardless of rainfall, which indicates continued fire suppression may threaten their already-declining populations. Most notably, the paucity of birds observed on the controls suggests that the current structure of the matrix developed as a result of fire suppression. Traditional pastoralism appears critical to the maintenance of avian diversity in these

  9. Effect of Suburban Development and Landscape Position on Water Quality in Three Small Watersheds Within the Croton System, New York.

    NASA Astrophysics Data System (ADS)

    Hassett, J. M.; Endreny, T. A.; Wolosoff, S.; Adam, M.; Mitchell, M. J.

    2003-12-01

    Internal hydrological processes in suburban watersheds and their effects on water quality warrant investigation. Instrument clusters (throughfall collectors, suction lysimeters, monitoring wells, and shallow and deep piezometers) were installed at several locations within three small (50 - 70 ha) watersheds (one forested, two with different degrees of suburban development) in the Croton Watershed, southeastern New York. Biweekly and storm samples were analyzed for base cations, selected anions, and DOC over a one-year period. The topographic index (TI) quantified landscape position; flowpath analyses determined degree of development at each cluster, using % impervious cover as the metric. Water quality degradation was observed in sites with medium and high TI values; no such effect was observed along the ridges, i.e., low TI values. At medium TI values, areas with more than 5% impervious had degraded water quality. At high TI values, the water chemistry degradation appeared at 10% or greater impervious surface

  10. Grassland structural heterogeneity in a savanna is driven more by productivity differences than by consumption differences between lawn and bunch grasses.

    PubMed

    Veldhuis, Michiel P; Fakkert, Heleen F; Berg, Matty P; Olff, Han

    2016-11-01

    Savanna grasslands are characterized by high spatial heterogeneity in vegetation structure, aboveground biomass and nutritional quality, with high quality short-grass grazing lawns forming mosaics with patches of tall bunch grasses of lower quality. This heterogeneity can arise because of local differences in consumption, because of differences in productivity, or because both processes enforce each other (more production and consumption). However, the relative importance of both processes in maintaining mosaics of lawn and bunch grassland types has not been measured. Also their interplay been not been assessed across landscape gradients. In a South African savanna, we, therefore, measured the seasonal changes in primary production, nutritional quality and herbivore consumption (amount and percentage) of grazing lawns and adjacent bunch grass patches across a rainfall gradient. We found both higher amounts of primary production and, to a smaller extent, consumption for bunch grass patches. In addition, for bunch grasses primary production increased towards higher rainfall while foliar nitrogen concentrations decreased. Foliar nitrogen concentrations of lawn grasses decreased much less with increasing rainfall. Consequently, large herbivores targeted the biomass produced on grazing lawns with on average 75 % of the produced biomass consumed. We conclude that heterogeneity in vegetation structure in this savanna ecosystem is better explained by small-scale differences in productivity between lawn and bunch grass vegetation types than by local differences in consumption rates. Nevertheless, the high nutritional quality of grazing lawns is highly attractive and, therefore, important for the maintenance of the heterogeneity in species composition (i.e. grazing lawn maintenance).

  11. Forest-savanna- morichal dynamics in relation to fire and human occupation in the southern Gran Sabana (SE Venezuela) during the last millennia

    NASA Astrophysics Data System (ADS)

    Montoya, Encarni; Rull, Valentí; Stansell, Nathan D.; Abbott, Mark B.; Nogué, Sandra; Bird, Broxton W.; Díaz, Wilmer A.

    2011-11-01

    The southern Gran Sabana (SE Venezuela) holds a particular type of neotropical savanna characterized by the local occurrence of morichales ( Mauritia palm swamps) , in a climate apparently more suitable for rain forests. We present a paleoecological analysis of the last millennia of Lake Chonita (4°39'N-61°0'W, 884 m elevation), based on biological and physico-chemical proxies. Savannas dominated the region during the last millennia, but a significant vegetation replacement occurred in recent times. The site was covered by a treeless savanna with nearby rainforests from 3640 to 2180 cal yr BP. Water levels were higher than today until about 2800 cal yr BP. Forests retreated since about 2180 cal yr BP onwards, likely influenced by a higher fire incidence that facilitated a dramatic expansion of morichales. The simultaneous appearance of charcoal particles and Mauritia pollen around 2000 cal yr BP supports the potential pyrophilous nature of this palm and the importance of fire for its recent expansion. The whole picture suggests human settlements similar to today - in which fire is an essential element - since around 2000 yr ago. Therefore, present-day southern Gran Sabana landscapes seem to have been the result of the synergy between biogeographical, climatic and anthropogenic factors, mostly fire.

  12. Developing a postglacial rockfall chronology in the mountainous fjord landscape of western Norway

    NASA Astrophysics Data System (ADS)

    Laute, Katja; Beylich, Achim A.; Winkler, Stefan

    2015-04-01

    Large areas of glacially sculpted mountain landscapes worldwide exhibit a high spatial density of postglacial rockfalls and rock-slope failures. However, the temporal patterns of rock-slope failure frequencies after Deglaciation are still fairly unknown. The mountainous fjord landscape in western Norway represents a suitable study area as it exhibits a high number of rockfalls and rock-slope failures within a region with a well known Deglaciation history. Two steep, parabolic-shaped and glacier-connected neighbouring drainage basins, Erdalen (79.5 km2) and Bødalen (60.1 km2), located on the western side of the Jostedalsbreen ice cap in western Norway are selected as study areas. The focus of this study is on (i) the temporal reconstruction of rockfalls and rock-slope failures within the two defined and nearly lithologically homogenous study areas and (ii) the identification and explanation of possible triggering and controlling factors of the investigated rock-slope failures. First investigations have started by applying Schmidt-hammer exposure-age dating (SHD) at seven larger rockfall deposits as well as at five moraines of known age within both study areas. During the sampling 50 to 100 impacts using a mechanical Proceq N-type instrument were taken from the surface of 5 to 50 single rockfall boulders located at the outer margin of the rockfall deposits. In order to avoid sampling of more recent rockfalls or redistributed debris material the sampling strategy selected preferred a larger number of individual boulders sampled with few impacts over sampling just a small number of boulders with a high number of multiple impacts. First results show that the mean rebound (R-) values measured at the seven rockfall deposits fall into recognizably different age categories. Based on the SHD measurements obtained from the moraines of known age, the determined rockfall age categories are situated between the Preboral and Little Ice Age period. The chronology and possible

  13. Aquaculture in artificially developed wetlands in urban areas: an application of the bivariate relationship between soil and surface water in landscape ecology.

    PubMed

    Paul, Abhijit

    2011-01-01

    Wetlands show a strong bivariate relationship between soil and surface water. Artificially developed wetlands help to build landscape ecology and make built environments sustainable. The bheries, wetlands of eastern Calcutta (India), utilize the city sewage to develop urban aquaculture that supports the local fish industries and opens a new frontier in sustainable environmental planning research.

  14. Differentiation of developing olfactory neurons analysed in terms of coupled epigenetic landscapes

    PubMed Central

    Alsing, Anne Katrine; Sneppen, Kim

    2013-01-01

    The olfactory system integrates signals from receptors expressed in olfactory sensory neurons. Each sensory neuron expresses only one of many similar olfactory receptors (ORs). The choice of receptor is made stochastically early in the differentiation process and is maintained throughout the life of the neuron. The underlying mechanism of this stochastic commitment to one of multiple similar OR genes remains elusive. We present a theoretical analysis of a mechanism that invokes important epigenetic properties of the system. The proposed model combines nucleosomes and associated read–write enzymes as mediators of a cis-acting positive feedback with a trans-acting negative feedback, thereby coupling the local epigenetic landscape of the individual OR genes in a way that allow one and only one gene to be active at any time. The model pinpoint that singular gene selection does not require transient mechanisms, enhancer elements or transcription factors to separate choice from maintenance. In addition, our hypothesis allow us to combine all reported characteristics of singular OR gene selection, in particular that OR genes are silenced from OR transgenes. Intriguingly, it predicts that OR transgenes placed in close proximity should always be expressed simultaneously, though rarely. PMID:23519617

  15. Differentiation of developing olfactory neurons analysed in terms of coupled epigenetic landscapes.

    PubMed

    Alsing, Anne Katrine; Sneppen, Kim

    2013-05-01

    The olfactory system integrates signals from receptors expressed in olfactory sensory neurons. Each sensory neuron expresses only one of many similar olfactory receptors (ORs). The choice of receptor is made stochastically early in the differentiation process and is maintained throughout the life of the neuron. The underlying mechanism of this stochastic commitment to one of multiple similar OR genes remains elusive. We present a theoretical analysis of a mechanism that invokes important epigenetic properties of the system. The proposed model combines nucleosomes and associated read-write enzymes as mediators of a cis-acting positive feedback with a trans-acting negative feedback, thereby coupling the local epigenetic landscape of the individual OR genes in a way that allow one and only one gene to be active at any time. The model pinpoint that singular gene selection does not require transient mechanisms, enhancer elements or transcription factors to separate choice from maintenance. In addition, our hypothesis allow us to combine all reported characteristics of singular OR gene selection, in particular that OR genes are silenced from OR transgenes. Intriguingly, it predicts that OR transgenes placed in close proximity should always be expressed simultaneously, though rarely.

  16. Late Tertiary and Quaternary landscape development in the western Grand Canyon and western Arizona strip

    SciTech Connect

    Billingsley, G.H. ); Wenrich, K.J. . Federal Center); Blackerby, B. )

    1993-04-01

    New geologic mapping of the western Grand Canyon and the Arizona Strip region, northwest Arizona, reveals young fault scarps on all faults, horsts, and graben structures. Tectonic activity here was previously thought to be at least Miocene age and older. New K-Ar age data for basalt flows in this region provide a basis for determining the age of surficial deposits in relation to elevated structural landforms. The basalts range in age from middle Miocene to late Pleistocene (17 Ma to 0.14 Ma). The Miocene basalts are found in the western Grand Canyon area and are progressively younger in a northeast direction onto the Shivwits and Uinkaret Plateaus, a distance of about 100 km. The older basalts are generally petrographically and chemically distinct from younger basalts. Those younger than one million years have less olivine and are chemically more iron- and titanium-rich suggesting they are from less primitive magmas. Basalt flows in this region older than 1 million years, are cut by faults showing equal displacement of the underlying strata and the flows. Basalt flows younger than 1 million years show offsets as much as 12 to 100 m, less than two-thirds the offset of underlying strata, implying that most tectonic activity occurred within the last 1 to 2 million years. Late Pliocene and Pleistocene faulting has extensively modified the landscape by elevated parts of the terrain resulting in young surficial deposits in lowland areas and rejuvenation of drainages in upthrown fault blocks.

  17. Significance of Epigenetic Landscape in Cartilage Regeneration from the Cartilage Development and Pathology Perspective

    PubMed Central

    Li, Jingting; Ohliger, James

    2014-01-01

    Regenerative therapies for cartilage defects have been greatly advanced by progress in both the stem cell biology and tissue engineering fields. Despite notable successes, significant barriers remain including shortage of autologous cell sources and generation of a stable chondrocyte phenotype using progenitor cells. Increasing demands for the treatment of degenerative diseases, such as osteoarthritis and rheumatoid arthritis, highlight the importance of epigenetic remodeling in cartilage regeneration. Epigenetic regulatory mechanisms, such as microRNAs, DNA methylation, and histone modifications, have been intensively studied due to their direct regulatory role on gene expression. However, a thorough understanding of the environmental factors that initiate these epigenetic events may provide greater insight into the prevention of degenerative diseases and improve the efficacy of treatments. In other words, if we could identify a specific factor from the environment and its downstream signaling events, then we could stop or retard degradation and enhance cartilage regeneration. A more operational definition of epigenetic remodeling has recently been proposed by categorizing the signals during the epigenetic process into epigenators, initiators, and maintainers. This review seeks to compile and reorganize the existing literature pertaining to epigenetic remodeling events placing emphasis on perceiving the landscape of epigenetic mechanisms during cartilage regeneration with the new operational definition, especially from the environmental factors' point of view. Progress in understanding epigenetic regulatory mechanisms could benefit cartilage regeneration and engineering on a larger scale and provide more promising therapeutic applications. PMID:24555773

  18. Significance of epigenetic landscape in cartilage regeneration from the cartilage development and pathology perspective.

    PubMed

    Li, Jingting; Ohliger, James; Pei, Ming

    2014-06-01

    Regenerative therapies for cartilage defects have been greatly advanced by progress in both the stem cell biology and tissue engineering fields. Despite notable successes, significant barriers remain including shortage of autologous cell sources and generation of a stable chondrocyte phenotype using progenitor cells. Increasing demands for the treatment of degenerative diseases, such as osteoarthritis and rheumatoid arthritis, highlight the importance of epigenetic remodeling in cartilage regeneration. Epigenetic regulatory mechanisms, such as microRNAs, DNA methylation, and histone modifications, have been intensively studied due to their direct regulatory role on gene expression. However, a thorough understanding of the environmental factors that initiate these epigenetic events may provide greater insight into the prevention of degenerative diseases and improve the efficacy of treatments. In other words, if we could identify a specific factor from the environment and its downstream signaling events, then we could stop or retard degradation and enhance cartilage regeneration. A more operational definition of epigenetic remodeling has recently been proposed by categorizing the signals during the epigenetic process into epigenators, initiators, and maintainers. This review seeks to compile and reorganize the existing literature pertaining to epigenetic remodeling events placing emphasis on perceiving the landscape of epigenetic mechanisms during cartilage regeneration with the new operational definition, especially from the environmental factors' point of view. Progress in understanding epigenetic regulatory mechanisms could benefit cartilage regeneration and engineering on a larger scale and provide more promising therapeutic applications.

  19. Impact of flow routing on catchment area calculations, slope estimates, and numerical simulations of landscape development

    NASA Astrophysics Data System (ADS)

    Shelef, Eitan; Hilley, George E.

    2013-12-01

    Flow routing across real or modeled topography determines the modeled discharge and wetness index and thus plays a central role in predicting surface lowering rate, runoff generation, likelihood of slope failure, and transition from hillslope to channel forming processes. In this contribution, we compare commonly used flow-routing rules as well as a new routing rule, to commonly used benchmarks. We also compare results for different routing rules using Airborne Laser Swath Mapping (ALSM) topography to explore the impact of different flow-routing schemes on inferring the generation of saturation overland flow and the transition between hillslope to channel forming processes, as well as on location of saturation overland flow. Finally, we examined the impact of flow-routing and slope-calculation rules on modeled topography produced by Geomorphic Transport Law (GTL)-based simulations. We found that different rules produce substantive differences in the structure of the modeled topography and flow patterns over ALSM data. Our results highlight the impact of flow-routing and slope-calculation rules on modeled topography, as well as on calculated geomorphic metrics across real landscapes. As such, studies that use a variety of routing rules to analyze and simulate topography are necessary to determine those aspects that most strongly depend on a chosen routing rule.

  20. Mediterranean savanna system: understanding and modeling of olive orchard.

    NASA Astrophysics Data System (ADS)

    Brilli, Lorenzo; Moriondo, Marco; Bindi, Marco

    2013-04-01

    Nowadays most of the studies on C and N exchange were focused on forest ecosystems and crop systems, while only few studies have been focused on so called "savanna systems". They are long-term agro-ecosystems (fruit trees, grapevines and olive trees, etc.) usually characterized by two different layers (ground vegetation and trees). Generally, there is a lack of knowledge about these systems due to their intrinsic structural complexity (different eco-physiological characteristics so as agricultural practices). However, given their long-term carbon storage capacity, these systems can play a fundamental role in terms of global C cycle. Among all of them, the role that olive trees can play in C sequestration should not be neglected, especially in Mediterranean areas where they typify the rural landscape and are widely cultivated (Loumou and Giourga, 2003). It is therefore fundamental modelling the C-fluxes exchanges coming from these systems through a tool able to well reproduce these dynamics in one of the most exposed areas to the risk of climate change (IPCC, 2007). In this work, 2 years of Net CO2 Ecosystem Exchange (NEE) measures from eddy covariance were used to test the biogeochemistry model DayCent. The study was conducted in a rain-fed olive orchard situated in Follonica, South Tuscany, Italy (42 ° 55'N, 10 ° 45'E), in an agricultural area near the coast. The instrumentation for flux measurement was placed 1.9 m above the canopy top (6.5 m from the ground) so that the footprint area, expressed as the area containing 90% of the observed flux, was almost entirely contained within the olive orchard limits (Brilli et al., in press). Ancillary slow sensors have included soil temperature profiles, global radiation, air temperature and humidity, rain gauge. Fluxes of sensible heat, latent heat, momentum and CO2 as well as ancillary data were derived at half-hourly time resolution. Specific soil (texture, current and historical land use and vegetation cover) and

  1. Mars Landscapes

    NASA Image and Video Library

    Spacecraft have studied the Martian surface for decades, giving Earthlings insights into the history, climate and geology of our nearest neighbor, Mars. These images are from "Mars Landscapes," a v...

  2. Sequence landscapes.

    PubMed Central

    Clift, B; Haussler, D; McConnell, R; Schneider, T D; Stormo, G D

    1986-01-01

    We describe a method for representing the structure of repeating sequences in nucleic-acids, proteins and other texts. A portion of the sequence is presented at the bottom of a CRT screen. Above the sequence is its landscape, which looks like a mountain range. Each mountain corresponds to a subsequence of the sequence. At the peak of every mountain is written the number of times that the subsequence appears. A data structure called a DAWG, which can be built in time proportional to the length of the sequence, is used to construct the landscape. For the 40 thousand bases of bacteriophage T7, the DAWG can be built in 30 seconds. The time to display any portion of the landscape is less than a second. Using sequence landscapes, one can quickly locate significant repeats. PMID:3753762

  3. Human induced prehistoric and historical soil erosion and landscape development in Southwestern USA

    NASA Astrophysics Data System (ADS)

    Dotterweich, Markus; Ivester, Andrew H.; Hanson, Paul R.; Daniel, Larsen; Dye, David H.; Foster, Thomas H., II

    2015-04-01

    gathered data will be used to i) compare the spatial extent of prehistoric and historic erosion and the short-term and long-term pedological and geomorphological effects of subtle soil erosion against extreme events, ii) assess the feedback-mechanisms of soil erosion on soil fertility and measurable land use changes in prehistorical and historical times, and (iii) estimate the long term effects of soil erosion and sediment deposition on archaeological features. The outcome will provide a decisive step forward to gather new qualitative and quantitative information on soil erosion during the Native American land use period to be able to achieve a better understanding of the long-term human induced landscape evolution in the uplands of the Southeastern USA and deliver data for a better predicting of landscape evolution to future climatic shifts in precipitation regimes.

  4. The MCH training program: developing MCH leaders that are equipped for the changing health care landscape.

    PubMed

    Kavanagh, Laura; Menser, Michelle; Pooler, Jennifer; Mathis, Sheryl; Ramos, Lauren Raskin

    2015-02-01

    This article examines the success of the Maternal and Child Health (MCH) Bureau's MCH Training Program in producing the next generation of MCH leaders, equipped with interdisciplinary, leadership skills necessary for the changing health care landscape. A secondary data analysis of performance measure data (2007-2011) collected through the discretionary grant information system was performed. Grantees were grouped by grant program (n = 10) for this analysis. Outcomes of interest 5 years post-program completion included: (1) the percentage of long-term training program graduates who demonstrate field leadership; (2) the percentage of long-term trainees (LTT) who remain in MCH, work with underserved and/or vulnerable populations, or work in a public health agency/organization; and (3) the percentage of LTT working in an interdisciplinary manner to serve the MCH population. Summary output data on the number of LTT reached was also calculated. The number of LTT participating in the MCH Training Program increased between 2007 and 2011. Over 84% of LTT demonstrate field leadership 5 years after program completion, while 78.2% of LTT remain in MCH work and 83% are working with underserved or vulnerable populations. At 5-years post-program completion, over 75% of LTT are working in an interdisciplinary manner to serve the MCH population. The MCH Training Program has produced well-positioned leaders. Continued investment in the MCH Training Program is critical to ensure a well-trained pipeline of health professionals equipped to address the special health needs of MCH populations in an evolving health system.

  5. Landscape Builder: software for the creation of initial landscapes for LANDIS from FIA data

    Treesearch

    William. Dijak

    2013-01-01

    I developed Landscape Builder to create spatially explicit landscapes as starting conditions for LANDIS Pro 7.0 and LANDIS II landscape forest simulation models from classified satellite imagery and Forest Inventory and Analysis (FIA) data collected over multiple years. LANDIS Pro and LANDIS II models project future landscapes by simulating tree growth, tree species...

  6. REMOTE SENSING AND SPATIALLY EXPLICIT LANDSCAPE-BASED NITROGEN MODELING METHODS DEVELOPMENT IN THE NEUSE RIVER BASIN, NC

    EPA Science Inventory

    The objective of this research was to model and map the spatial patterns of excess nitrogen (N) sources across the landscape within the Neuse River Basin (NRB) of North
    Carolina. The process included an initial land cover characterization effort to map landscape "patches" at ...

  7. REMOTE SENSING AND SPATIALLY EXPLICIT LANDSCAPE-BASED NITROGEN MODELING METHODS DEVELOPMENT IN THE NEUSE RIVER BASIN, NC

    EPA Science Inventory

    The objective of this research was to model and map the spatial patterns of excess nitrogen (N) sources across the landscape within the Neuse River Basin (NRB) of North
    Carolina. The process included an initial land cover characterization effort to map landscape "patches" at ...

  8. Landscape evolution (A Review)

    PubMed Central

    Sharp, Robert P.

    1982-01-01

    Landscapes are created by exogenic and endogenic processes acting along the interface between the lithosphere and the atmosphere and hydrosphere. Various landforms result from the attack of weathering and erosion upon the highly heterogeneous lithospheric surface. Landscapes are dynamic, acutely sensitive to natural and artificial perturbation. Undisturbed, they can evolve through a succession of stages to a plain of low relief. Often, the progression of an erosion cycle is interrupted by tectonic or environmental changes; thus, many landscapes preserve vestiges of earlier cycles useful in reconstructing the recent history of Earth's surface. Landforms are bounded by slopes, so their evolution is best understood through study of slopes and the complex of factors controlling slope character and development. The substrate, biosphere, climatic environment, and erosive processes are principal factors. Creep of the disintegrated substrate and surface wash by water are preeminent. Some slopes attain a quasisteady form and recede parallel to themselves (backwearing); others become ever gentler with time (downwearing). The lovely convex/rectilinear/concave profile of many debris-mantled slopes reflects an interplay between creep and surface wash. Landscapes of greatest scenic attraction are usually those in which one or two genetic factors have strongly dominated or those perturbed by special events. Nature has been perturbing landscapes for billions of years, so mankind can learn about landscape perturbation from natural examples. Images

  9. In situ development of high-elevation, low-relief landscapes via duplex deformation in the Eastern Himalayan hinterland, Bhutan

    NASA Astrophysics Data System (ADS)

    Adams, B. A.; Whipple, K. X.; Hodges, K. V.; Heimsath, A. M.

    2016-02-01

    Prior studies have proposed tectonic and climatic mechanisms to explain surface uplift throughout the Bhutan Himalaya. While the resulting enigmatic, low-relief landscapes, elevated above deeply incised canyons, are a popular setting to test ideas of interacting tectonic and climatic forces, when and why these landscapes formed is still debated. We test the idea that these landscapes were created by a spatially variable and recent increase in rock uplift rate associated with the formation of structural duplexes at depth. We utilize a new suite of erosion rates derived from detrital cosmogenic nuclide techniques, geomorphic observations, and a landscape evolution model to demonstrate the viability of this hypothesis. Low-relief landscapes in Bhutan are eroding at a rate of ~70 m/Ma, while basins from surrounding steep landscapes yield erosion rates of ~950 m/Ma, demonstrating that this portion of the range is in a transient period of increasing relief. Applying insights from our erosion rates, we explore the influence of an active duplex on overlying topography using a landscape evolution model by imposing a high rock uplift rate in the middle of a mountain range. Our simulations show that low-relief landscapes with thick alluvial fills form upstream of convex knickpoints as rivers adjust to higher uplift rates downstream, a pattern consistent with geologic, geomorphic, and thermochronometric data from Bhutan. With our new erosion rates, reconstructed paleo-river profiles, and landscape evolution simulations, we show that the low-relief landscapes were formed in situ as they were uplifted ~800 m in the past ~0.8-1 Ma.

  10. The development and application of landscape evolution models to coupled coast-estuarine environments

    NASA Astrophysics Data System (ADS)

    Morris, Chloe; Coulthard, Tom; Parsons, Daniel R.; Manson, Susan; Barkwith, Andrew

    2017-04-01

    Landscape Evolution Models (LEMs) are proven to be useful tools in understanding the morphodynamics of coast and estuarine systems. However, perhaps owing to the lack of research in this area, current models are not capable of simulating the dynamic interactions between these systems and their co-evolution at the meso-scale. Through a novel coupling of numerical models, this research is designed to explore coupled coastal-estuarine interactions, controls on system behaviour and the influence that environmental change could have. This will contribute to the understanding of the morphodynamics of these systems and how they may behave and evolve over the next century in response to climate changes, with the aim of informing management practices. This goal is being achieved through the modification and coupling of the one-line Coastline Evolution Model (CEM) with the hydrodynamic LEM CAESAR-Lisflood (C-L). The major issues faced with coupling these programs are their differing complexities and the limited graphical visualisations produced by the CEM that hinder the dissemination of results. The work towards overcoming these issues and reported here, include a new version of the CEM that incorporates a range of more complex geomorphological processes and boasts a graphical user interface that guides users through model set-up and projects a live output during model runs. The improved version is a stand-alone tool that can be used for further research projects and for teaching purposes. A sensitivity analysis using the Morris method has been completed to identify which key variables, including wave climate, erosion and weathering values, dominate the control of model behaviour. The model is being applied and tested using the evolution of the Holderness Coast, Humber Estuary and Spurn Point on the east coast of England (UK), which possess diverse geomorphologies and complex, co-evolving sediment pathways. Simulations using the modified CEM are currently being completed to

  11. Fuel management in the Subtropical and Savanna divisions

    Treesearch

    Kenneth W. Outcalt

    2012-01-01

    The Subtropical Division (230) and Savanna Division (410), both based on Bailey’s (1996) ecoregions, are found in the Southern United States (http://www.na.fs.fed.us/fire/cwedocs/map%20new_divisions.pdf). The Subtropical Division occupies the southern Atlantic and Gulf coastal areas. It is characterized by a humid subtropical climate with hot humid summers (chapter 3...

  12. African Savanna-Forest Boundary Dynamics: A 20-Year Study.

    PubMed

    Cuni-Sanchez, Aida; White, Lee J T; Calders, Kim; Jeffery, Kathryn J; Abernethy, Katharine; Burt, Andrew; Disney, Mathias; Gilpin, Martin; Gomez-Dans, Jose L; Lewis, Simon L

    2016-01-01

    Recent studies show widespread encroachment of forest into savannas with important consequences for the global carbon cycle and land-atmosphere interactions. However, little research has focused on in situ measurements of the successional sequence of savanna to forest in Africa. Using long-term inventory plots we quantify changes in vegetation structure, above-ground biomass (AGB) and biodiversity of trees ≥10 cm diameter over 20 years for five vegetation types: savanna; colonising forest (F1), monodominant Okoume forest (F2); young Marantaceae forest (F3); and mixed Marantaceae forest (F4) in Lopé National Park, central Gabon, plus novel 3D terrestrial laser scanning (TLS) measurements to assess forest structure differences. Over 20 years no plot changed to a new stage in the putative succession, but F1 forests strongly moved towards the structure, AGB and diversity of F2 forests. Overall, savanna plots showed no detectable change in structure, AGB or diversity using this method, with zero trees ≥10 cm diameter in 1993 and 2013. F1 and F2 forests increased in AGB, mainly as a result of adding recruited stems (F1) and increased Basal Area (F2), whereas F3 and F4 forests did not change substantially in structure, AGB or diversity. Critically, the stability of the F3 stage implies that this stage may be maintained for long periods. Soil carbon was low, and did not show a successional gradient as for AGB and diversity. TLS vertical plant profiles showed distinctive differences amongst the vegetation types, indicating that this technique can improve ecological understanding. We highlight two points: (i) as forest colonises, changes in biodiversity are much slower than changes in forest structure or AGB; and (ii) all forest types store substantial quantities of carbon. Multi-decadal monitoring is likely to be required to assess the speed of transition between vegetation types.

  13. African Savanna-Forest Boundary Dynamics: A 20-Year Study

    PubMed Central

    Cuni-Sanchez, Aida; White, Lee J. T.; Calders, Kim; Jeffery, Kathryn J.; Abernethy, Katharine; Burt, Andrew; Disney, Mathias; Gilpin, Martin; Gomez-Dans, Jose L.; Lewis, Simon L.

    2016-01-01

    Recent studies show widespread encroachment of forest into savannas with important consequences for the global carbon cycle and land-atmosphere interactions. However, little research has focused on in situ measurements of the successional sequence of savanna to forest in Africa. Using long-term inventory plots we quantify changes in vegetation structure, above-ground biomass (AGB) and biodiversity of trees ≥10 cm diameter over 20 years for five vegetation types: savanna; colonising forest (F1), monodominant Okoume forest (F2); young Marantaceae forest (F3); and mixed Marantaceae forest (F4) in Lopé National Park, central Gabon, plus novel 3D terrestrial laser scanning (TLS) measurements to assess forest structure differences. Over 20 years no plot changed to a new stage in the putative succession, but F1 forests strongly moved towards the structure, AGB and diversity of F2 forests. Overall, savanna plots showed no detectable change in structure, AGB or diversity using this method, with zero trees ≥10 cm diameter in 1993 and 2013. F1 and F2 forests increased in AGB, mainly as a result of adding recruited stems (F1) and increased Basal Area (F2), whereas F3 and F4 forests did not change substantially in structure, AGB or diversity. Critically, the stability of the F3 stage implies that this stage may be maintained for long periods. Soil carbon was low, and did not show a successional gradient as for AGB and diversity. TLS vertical plant profiles showed distinctive differences amongst the vegetation types, indicating that this technique can improve ecological understanding. We highlight two points: (i) as forest colonises, changes in biodiversity are much slower than changes in forest structure or AGB; and (ii) all forest types store substantial quantities of carbon. Multi-decadal monitoring is likely to be required to assess the speed of transition between vegetation types. PMID:27336632

  14. Microbial Diversity in Cerrado Biome (Neotropical Savanna) Soils

    PubMed Central

    Pereira de Castro, Alinne; Sartori da Silva, Maria Regina Silveira; Quirino, Betania Ferraz; da Cunha Bustamante, Mercedes Maria; Krüger, Ricardo Henrique

    2016-01-01

    The Cerrado, the largest savanna region in South America, is located in central Brazil. Cerrado physiognomies, which range from savanna grasslands to forest formations, combined with the highly weathered, acidic clay Cerrado soils form a unique ecoregion. In this study, high-throughput sequencing of ribosomal RNA genes was combined with shotgun metagenomic analysis to explore the taxonomic composition and potential functions of soil microbial communities in four different vegetation physiognomies during both dry and rainy seasons. Our results showed that changes in bacterial, archaeal, and fungal community structures in cerrado denso, cerrado sensu stricto, campo sujo, and gallery forest soils strongly correlated with seasonal patterns of soil water uptake. The relative abundance of AD3, WPS-2, Planctomycetes, Thermoprotei, and Glomeromycota typically decreased in the rainy season, whereas the relative abundance of Proteobacteria and Ascomycota increased. In addition, analysis of shotgun metagenomic data revealed a significant increase in the relative abundance of genes associated with iron acquisition and metabolism, dormancy, and sporulation during the dry season, and an increase in the relative abundance of genes related to respiration and DNA and protein metabolism during the rainy season. These gene functional categories are associated with adaptation to water stress. Our results further the understanding of how tropical savanna soil microbial communities may be influenced by vegetation covering and temporal variations in soil moisture. PMID:26849674

  15. Regional insight into savanna hydrogeomorphology from termite mounds.

    PubMed

    Levick, Shaun R; Asner, Gregory P; Chadwick, Oliver A; Khomo, Lesego M; Rogers, Kevin H; Hartshorn, Anthony S; Kennedy-Bowdoin, Ty; Knapp, David E

    2010-09-07

    Global vegetation models predict the spread of woody vegetation in African savannas and grasslands under future climate scenarios, but they operate too broadly to consider hillslope-scale variations in tree-grass distribution. Topographically linked hydrology-soil-vegetation sequences, or catenas, underpin a variety of ecological processes in savannas, including responses to climate change. In this study, we explore the three-dimensional structure of hillslopes and vegetation, using high-resolution airborne LiDAR (Light Detection And Ranging), to understand the long-term effects of mean annual precipitation (MAP) on catena pattern. Our results reveal that the presence and position of hillslope hydrological boundaries, or seeplines, vary as a function of MAP through its long-term influence on clay redistribution. We suggest that changes in climate will differentially alter the structure of savannas through hydrological changes to the seasonally saturated grasslands downslope of seeplines. The mechanisms underlying future woody encroachment are not simply physiological responses to elevated temperatures and CO(2) levels but also involve hydrogeomorphological processes at the hillslope scale.

  16. Microbial Diversity in Cerrado Biome (Neotropical Savanna) Soils.

    PubMed

    de Castro, Alinne Pereira; Sartori da Silva, Maria Regina Silveira; Quirino, Betania Ferraz; da Cunha Bustamante, Mercedes Maria; Krüger, Ricardo Henrique

    2016-01-01

    The Cerrado, the largest savanna region in South America, is located in central Brazil. Cerrado physiognomies, which range from savanna grasslands to forest formations, combined with the highly weathered, acidic clay Cerrado soils form a unique ecoregion. In this study, high-throughput sequencing of ribosomal RNA genes was combined with shotgun metagenomic analysis to explore the taxonomic composition and potential functions of soil microbial communities in four different vegetation physiognomies during both dry and rainy seasons. Our results showed that changes in bacterial, archaeal, and fungal community structures in cerrado denso, cerrado sensu stricto, campo sujo, and gallery forest soils strongly correlated with seasonal patterns of soil water uptake. The relative abundance of AD3, WPS-2, Planctomycetes, Thermoprotei, and Glomeromycota typically decreased in the rainy season, whereas the relative abundance of Proteobacteria and Ascomycota increased. In addition, analysis of shotgun metagenomic data revealed a significant increase in the relative abundance of genes associated with iron acquisition and metabolism, dormancy, and sporulation during the dry season, and an increase in the relative abundance of genes related to respiration and DNA and protein metabolism during the rainy season. These gene functional categories are associated with adaptation to water stress. Our results further the understanding of how tropical savanna soil microbial communities may be influenced by vegetation covering and temporal variations in soil moisture.

  17. Landscape-scale observations of plant water use using continuous stable isotope monitoring

    NASA Astrophysics Data System (ADS)

    Wang, L.; Caylor, K. K.; Good, S. P.; Villegas, J. C.; Breshears, D. D.

    2009-12-01

    Water vapor isotopes (δ2H and δ18O) are useful for resolving the dynamics of the near-surface atmospheric water cycle across a range of temporal and spatial scales. Previously, insight was limited by the temporal resolution of available measurement and sampling techniques. In recent years, with the development of laser-based spectroscopy techniques, continuous monitoring of δ2H and δ18O compositions in water vapor has become feasible. In this study, we reported two experiments, one conducted within a sealed mega-scale chamber (Biosphere 2) and another in an African savanna ecosystem. These studies were conducted to examine the feasibility of continuously monitoring the isotopic composition of surface evapotranspiration by coupling isotope and eddy covariance techniques. Results from the Biosphere 2 glasshouse facility provided clear evidence of the method’s ability to track the impact of diurnal cycles in plant transpiration on atmospheric isotope composition. In addition, patterns of isotopic vapor composition were well-correlated to experimental manipulations of vegetation cover, which we related to changes in the relative amounts of evaporation and transpiration. Preliminary results for the field experiment conducted in a Kenyan savanna revealed a rapid, dramatic shift in the isotopic composition of near-surface water vapor after a very small rainfall event (~1 mm), which was likely caused by the canopy/soil evaporation. Our field observations also indicated that soil moisture/potential may play a role in determining the evaporation signals. Taken as a whole, these experiments confirm the potential of laser based continuous isotope monitoring as a means for greatly expanding the use of isotope flux measurements to address a wide range of research topics related to landscape-scale plant water use in drylands.

  18. Edge-effect interactions in fragmented and patchy landscapes.

    PubMed

    Porensky, Lauren M; Young, Truman P

    2013-06-01

    Ecological edges are increasingly recognized as drivers of landscape patterns and ecosystem processes. In fragmented and patchy landscapes (e.g., a fragmented forest or a savanna with scattered termite mounds), edges can become so numerous that their effects pervade the entire landscape. Results of recent studies in such landscapes show that edge effects can be altered by the presence or proximity of other nearby edges. We considered the theoretical significance of edge-effect interactions, illustrated various landscape configurations that support them and reviewed existing research on this topic. Results of studies from a variety of locations and ecosystem types show that edge-effect interactions can have significant consequences for ecosystems and conservation, including higher tree mortality rates in tropical rainforest fragments, reduced bird densities in grassland fragments, and bush encroachment and reduced wildlife densities in a tropical savanna. To clarify this underappreciated concept and synthesize existing work, we devised a conceptual framework for edge-effect interactions. We first worked to reduce terminological confusion by clarifying differences among terms such as edge intersection and edge interaction. For cases in which nearby edge effects interact, we proposed three possible forms of interaction: strengthening (presence of a second edge causes stronger edge effects), weakening (presence of a second edge causes weaker edge effects), and emergent (edge effects change completely in the presence of a second edge). By clarifying terms and concepts, this framework enables more precise descriptions of edge-effect interactions and facilitates comparisons of results among disparate study systems and response variables. A better understanding of edge-effect interactions will pave the way for more appropriate modeling, conservation, and management in complex landscapes. © 2013 Society for Conservation Biology.

  19. Identifying Greater Sage-Grouse source and sink habitats for conservation planning in an energy development landscape.

    PubMed

    Kirol, Christopher P; Beck, Jeffrey L; Huzurbazar, Snehalata V; Holloran, Matthew J; Miller, Scott N

    2015-06-01

    Conserving a declining species that is facing many threats, including overlap of its habitats with energy extraction activities, depends upon identifying and prioritizing the value of the habitats that remain. In addition, habitat quality is often compromised when source habitats are lost or fragmented due to anthropogenic development. Our objective was to build an ecological model to classify and map habitat quality in terms of source or sink dynamics for Greater Sage-Grouse (Centrocercus urophasianus) in the Atlantic Rim Project Area (ARPA), a developing coalbed natural gas field in south-central Wyoming, USA. We used occurrence and survival modeling to evaluate relationships between environmental and anthropogenic variables at multiple spatial scales and for all female summer life stages, including nesting, brood-rearing, and non-brooding females. For each life stage, we created resource selection functions (RSFs). We weighted the RSFs and combined them to form a female summer occurrence map. We modeled survival also as a function of spatial variables for nest, brood, and adult female summer survival. Our survival-models were mapped as survival probability functions individually and then combined with fixed vital rates in a fitness metric model that, when mapped, predicted habitat productivity (productivity map). Our results demonstrate a suite of environmental and anthropogenic variables at multiple scales that were predictive of occurrence and survival. We created a source-sink map by overlaying our female summer occurrence map and productivity map to predict habitats contributing to population surpluses (source habitats) or deficits (sink habitat) and low-occurrence habitats on the landscape. The source-sink map predicted that of the Sage-Grouse habitat within the ARPA, 30% was primary source, 29% was secondary source, 4% was primary sink, 6% was secondary sink, and 31% was low occurrence. Our results provide evidence that energy development and avoidance of

  20. The initial phase of a Longleaf Pine-Wiregrass Savanna restoration: species establishment and community responses.

    SciTech Connect

    Aschenbach, Todd, A; Foster, Bryan, L.; Imm, Donald, W.

    2010-09-01

    AbstractAbstract The significant loss of the longleaf pine-wiregrass ecosystem in the southeastern United States has serious implications for biodiversity and ecosystem functioning. In response to this loss, we have initiated a long-term and landscape-scale restoration experiment at the 80,125 ha (310 mi2) Department of Energy Savannah River Site (SRS) located near Aiken, South Carolina. Aristida beyrichiana (wiregrass), an important and dominant grass (i.e., a “matrix” species) of the longleaf pine savanna understory, and 31 other herbaceous “non-matrix” species were planted at six locations throughout SRS in 2002 and 2003. Of the 36,056 transplanted seedlings, 75% were still alive in June 2004, while mean 1–2 year survival across all planted species was 48%. Lespedeza hirta (hairy lespedeza) exhibited the greatest overall survival per 3 ×3 m cell at 95%, whereas Schizachyrium spp. (little bluestem) exhibited the greatest mean cover among individual species at 5.9%. Wiregrass survival and cover were significantly reduced when planted with non-matrix species. Aggregate cover of all planted species in restored cells averaged 25.9% in 2006. High rates of survival and growth of the planted species resulted in greater species richness (SR), diversity, and vegetative cover in restored cells. Results suggest that the loss of the longleaf pine-wiregrass ecosystem may be ameliorated through restoration efforts and illustrate the positive impact of restoration plantings on biodiversity and vegetative cover.

  1. More than carbon sequestration: Biophysical climate benefits of restored savanna woodlands

    PubMed Central

    Syktus, Jozef I.; McAlpine, Clive A.

    2016-01-01

    Deforestation and climate change are interconnected and represent major environmental challenges. Here, we explore the capacity of regional-scale restoration of marginal agricultural lands to savanna woodlands in Australia to reduce warming and drying resulting from increased concentration of greenhouse gases. We show that restoration triggers a positive feedback loop between the land surface and the atmosphere, characterised by increased evaporative fraction, eddy dissipation and turbulent mixing in the boundary-layer resulting in enhanced cloud formation and precipitation over the restored regions. The increased evapotranspiration results from the capacity deep-rooted woody vegetation to access soil moisture. As a consequence, the increase in precipitation provides additional moisture to soil and trees, thus reinforcing the positive feedback loop. Restoration reduced the rate of warming and drying under the transient increase in the radiative forcing of greenhouse gas emissions (RCP8.5). At the continental scale, average summer warming for all land areas was reduced by 0.18 oC from 4.1 oC for the period 2056–2075 compared to 1986–2005. For the restored regions (representing 20% of Australia), the averaged surface temperature increase was 3.2 °C which is 0.82 °C cooler compared to agricultural landscapes. Further, there was reduction of 12% in the summer drying of the near-surface soil for the restored regions. PMID:27373738

  2. More than carbon sequestration: Biophysical climate benefits of restored savanna woodlands

    NASA Astrophysics Data System (ADS)

    Syktus, Jozef I.; McAlpine, Clive A.

    2016-07-01

    Deforestation and climate change are interconnected and represent major environmental challenges. Here, we explore the capacity of regional-scale restoration of marginal agricultural lands to savanna woodlands in Australia to reduce warming and drying resulting from increased concentration of greenhouse gases. We show that restoration triggers a positive feedback loop between the land surface and the atmosphere, characterised by increased evaporative fraction, eddy dissipation and turbulent mixing in the boundary-layer resulting in enhanced cloud formation and precipitation over the restored regions. The increased evapotranspiration results from the capacity deep-rooted woody vegetation to access soil moisture. As a consequence, the increase in precipitation provides additional moisture to soil and trees, thus reinforcing the positive feedback loop. Restoration reduced the rate of warming and drying under the transient increase in the radiative forcing of greenhouse gas emissions (RCP8.5). At the continental scale, average summer warming for all land areas was reduced by 0.18 oC from 4.1 oC for the period 2056–2075 compared to 1986–2005. For the restored regions (representing 20% of Australia), the averaged surface temperature increase was 3.2 °C which is 0.82 °C cooler compared to agricultural landscapes. Further, there was reduction of 12% in the summer drying of the near-surface soil for the restored regions.

  3. More than carbon sequestration: Biophysical climate benefits of restored savanna woodlands.

    PubMed

    Syktus, Jozef I; McAlpine, Clive A

    2016-07-04

    Deforestation and climate change are interconnected and represent major environmental challenges. Here, we explore the capacity of regional-scale restoration of marginal agricultural lands to savanna woodlands in Australia to reduce warming and drying resulting from increased concentration of greenhouse gases. We show that restoration triggers a positive feedback loop between the land surface and the atmosphere, characterised by increased evaporative fraction, eddy dissipation and turbulent mixing in the boundary-layer resulting in enhanced cloud formation and precipitation over the restored regions. The increased evapotranspiration results from the capacity deep-rooted woody vegetation to access soil moisture. As a consequence, the increase in precipitation provides additional moisture to soil and trees, thus reinforcing the positive feedback loop. Restoration reduced the rate of warming and drying under the transient increase in the radiative forcing of greenhouse gas emissions (RCP8.5). At the continental scale, average summer warming for all land areas was reduced by 0.18 (o)C from 4.1 (o)C for the period 2056-2075 compared to 1986-2005. For the restored regions (representing 20% of Australia), the averaged surface temperature increase was 3.2 °C which is 0.82 °C cooler compared to agricultural landscapes. Further, there was reduction of 12% in the summer drying of the near-surface soil for the restored regions.

  4. A LANDSCAPE DEVELOPMENT INTENSITY MAP OF MARYLAND, USA - 4/07

    EPA Science Inventory

    We present a map of human development intensity for central and eastern Maryland using an index derived from energy systems principles. Brown and Vivas developed a measure of the intensity of human development based on the nonrenewable energy use per unit area as an index to exp...

  5. A LANDSCAPE DEVELOPMENT INTENSITY MAP OF MARYLAND, USA - 4/07

    EPA Science Inventory

    We present a map of human development intensity for central and eastern Maryland using an index derived from energy systems principles. Brown and Vivas developed a measure of the intensity of human development based on the nonrenewable energy use per unit area as an index to exp...

  6. A novel approach for the development of tiered use biological criteria for rivers and streams in an ecologically diverse landscape.

    PubMed

    Bouchard, R William; Niemela, Scott; Genet, John A; Yoder, Chris O; Sandberg, John; Chirhart, Joel W; Feist, Mike; Lundeen, Benjamin; Helwig, Dan

    2016-03-01

    Water resource protection goals for aquatic life are often general and can result in under protection of some high quality water bodies and unattainable expectations for other water bodies. More refined aquatic life goals known as tiered aquatic life uses (TALUs) provide a framework to designate uses by setting protective goals for high quality water bodies and establishing attainable goals for water bodies altered by legally authorized legacy activities (e.g., channelization). Development of biological criteria or biocriteria typically requires identification of a set of least- or minimally-impacted reference sites that are used to establish a baseline from which goals are derived. Under a more refined system of stream types and aquatic life use goals, an adequate set of reference sites is needed to account for the natural variability of aquatic communities (e.g., landscape differences, thermal regime, and stream size). To develop sufficient datasets, Minnesota employed a reference condition approach in combination with an approach based on characterizing a stream's response to anthropogenic disturbance through development of a Biological Condition Gradient (BCG). These two approaches allowed for the creation of ecologically meaningful and consistent biocriteria within a more refined stream typology and solved issues related to small sample sizes and poor representation of minimally- or least-disturbed conditions for some stream types. Implementation of TALU biocriteria for Minnesota streams and rivers will result in consistent and protective goals that address fundamental differences among waters in terms of their potential for restoration.

  7. Advancements in Hydrology and Erosion Process Understanding and Post-Fire Hydrologic and Erosion Model Development for Semi-Arid Landscapes

    NASA Astrophysics Data System (ADS)

    Williams, C. Jason; Pierson, Frederick B.; Al-Hamdan, Osama Z.; Robichaud, Peter R.; Nearing, Mark A.; Hernandez, Mariano; Weltz, Mark A.; Spaeth, Kenneth E.; Goodrich, David C.

    2017-04-01

    Fire activity continues to increase in semi-arid regions around the globe. Private and governmental land management entities are challenged with predicting and mitigating post-fire hydrologic and erosion responses on these landscapes. For more than a decade, a team of scientists with the US Department of Agriculture has collaborated on extensive post-fire hydrologic field research and the application of field research to development of post-fire hydrology and erosion predictive technologies. Experiments funded through this research investigated the impacts of fire on vegetation and soils and the effects of these fire-induced changes on infiltration, runoff generation, erodibility, and soil erosion processes. The distribution of study sites spans diverse topography across grassland, shrubland, and woodland landscapes throughout the western United States. Knowledge gleaned from the extensive field experiments was applied to develop and enhance physically-based models for hillslope- to watershed-scale runoff and erosion prediction. Our field research and subsequent data syntheses have identified key knowledge gaps and challenges regarding post-fire hydrology and erosion modeling. Our presentation details some consistent trends across a diverse domain and varying landscape conditions based on our extensive field campaigns. We demonstrate how field data have advanced our understanding of post-fire hydrology and erosion for semi-arid landscapes and highlight remaining key knowledge gaps. Lastly, we briefly show how our well-replicated experimental methodologies have contributed to advancements in hydrologic and erosion model development for the post-fire environment.

  8. Structural, physiognomic and above-ground biomass variation in savanna-forest transition zones on three continents - how different are co-occurring savanna and forest formations?

    NASA Astrophysics Data System (ADS)

    Veenendaal, E. M.; Torello-Raventos, M.; Feldpausch, T. R.; Domingues, T. F.; Gerard, F.; Schrodt, F.; Saiz, G.; Quesada, C. A.; Djagbletey, G.; Ford, A.; Kemp, J.; Marimon, B. S.; Marimon-Junior, B. H.; Lenza, E.; Ratter, J. A.; Maracahipes, L.; Sasaki, D.; Sonke, B.; Zapfack, L.; Villarroel, D.; Schwarz, M.; Yoko Ishida, F.; Gilpin, M.; Nardoto, G. B.; Affum-Baffoe, K.; Arroyo, L.; Bloomfield, K.; Ceca, G.; Compaore, H.; Davies, K.; Diallo, A.; Fyllas, N. M.; Gignoux, J.; Hien, F.; Johnson, M.; Mougin, E.; Hiernaux, P.; Killeen, T.; Metcalfe, D.; Miranda, H. S.; Steininger, M.; Sykora, K.; Bird, M. I.; Grace, J.; Lewis, S.; Phillips, O. L.; Lloyd, J.

    2015-05-01

    Through interpretations of remote-sensing data and/or theoretical propositions, the idea that forest and savanna represent "alternative stable states" is gaining increasing acceptance. Filling an observational gap, we present detailed stratified floristic and structural analyses for forest and savanna stands located mostly within zones of transition (where both vegetation types occur in close proximity) in Africa, South America and Australia. Woody plant leaf area index variation was related to tree canopy cover in a similar way for both savanna and forest with substantial overlap between the two vegetation types. As total woody plant canopy cover increased, so did the relative contribution of middle and lower strata of woody vegetation. Herbaceous layer cover declined as woody cover increased. This pattern of understorey grasses and herbs progressively replaced by shrubs as the canopy closes over was found for both savanna and forests and on all continents. Thus, once subordinate woody canopy layers are taken into account, a less marked transition in woody plant cover across the savanna-forest-species discontinuum is observed compared to that inferred when trees of a basal diameter > 0.1 m are considered in isolation. This is especially the case for shrub-dominated savannas and in taller savannas approaching canopy closure. An increased contribution of forest species to the total subordinate cover is also observed as savanna stand canopy closure occurs. Despite similarities in canopy-cover characteristics, woody vegetation in Africa and Australia attained greater heights and stored a greater amount of above-ground biomass than in South America. Up to three times as much above-ground biomass is stored in forests compared to savannas under equivalent climatic conditions. Savanna-forest transition zones were also found to typically occur at higher precipitation regimes for South America than for Africa. Nevertheless, consistent across all three continents coexistence

  9. Effects of Urban Development on Water Quality in the Piedmont of North Carolina: Association of Landscape Variables With Water Quality

    NASA Astrophysics Data System (ADS)

    Harned, D. A.; Cuffney, T. F.

    2005-12-01

    An assessment of effects of urban development on water quality in the Piedmont of North Carolina is part of the U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program. Thirty sites along a gradient of undeveloped to fully urbanized basins were selected using geographic information analysis to control variability in natural factors that influence water quality. Data collected include nutrient, pesticide, ion, and dissolved-oxygen concentrations, temperature, pH, specific conductance, streamflow, stage, habitat characteristics, and algal, benthic invertebrate, and fish communities. Sampling for water chemistry ranged from two samples (at 20 sites) to six samples (at 10 sites) per year from October 2002 to September 2003. Geomorphic and biological data were collected once in each basin. An index that integrates information on human influences, including land cover, population, and socioeconomic characteristics was used to define the urban gradient and to select sites. Relations among landscape, streamflow, temperature, and water-chemistry variables were analyzed to define urban effects on water quality. Distinct patterns of association occurred between landscape variables and water quality. An increase in urban index is associated with increases in pH (r=0.60), specific conductance (0.72), sulfate (0.68), a multiple-constituent chemical index (0.91), and a pesticide index (0.76). Landscape characteristics correlated with water quality in a similar manner. Increasing basin population density is associated with higher pH (0.55, 1990; 0.56, 2000), specific conductance (0.71, 1990), chloride (0.66, 1990), sulfate (0.72), and pesticides (0.71, 1990; 0.68, 2000). This pattern also is reflected in household density (pH (0.60), chemical index (0.87), and pesticide index (0.68)); in the total percentage of developed land in the basin (specific conductance (0.85), chloride (0.77), sulfate (0.81), total nitrogen (0.50), chemical index (0.84), and pesticide

  10. Exploring water cycle dynamics by sampling multiple stable water isotope pools in a developed landscape in Germany

    NASA Astrophysics Data System (ADS)

    Orlowski, Natalie; Kraft, Philipp; Pferdmenges, Jakob; Breuer, Lutz

    2016-09-01

    A dual stable water isotope (δ2H and δ18O) study was conducted in the developed (managed) landscape of the Schwingbach catchment (Germany). The 2-year weekly to biweekly measurements of precipitation, stream, and groundwater isotopes revealed that surface and groundwater are isotopically disconnected from the annual precipitation cycle but showed bidirectional interactions between each other. Apparently, snowmelt played a fundamental role for groundwater recharge explaining the observed differences to precipitation δ values. A spatially distributed snapshot sampling of soil water isotopes at two soil depths at 52 sampling points across different land uses (arable land, forest, and grassland) revealed that topsoil isotopic signatures were similar to the precipitation input signal. Preferential water flow paths occurred under forested soils, explaining the isotopic similarities between top- and subsoil isotopic signatures. Due to human-impacted agricultural land use (tilling and compression) of arable and grassland soils, water delivery to the deeper soil layers was reduced, resulting in significant different isotopic signatures. However, the land use influence became less pronounced with depth and soil water approached groundwater δ values. Seasonally tracing stable water isotopes through soil profiles showed that the influence of new percolating soil water decreased with depth as no remarkable seasonality in soil isotopic signatures was obvious at depths > 0.9 m and constant values were observed through space and time. Since classic isotope evaluation methods such as transfer-function-based mean transit time calculations did not provide a good fit between the observed and calculated data, we established a hydrological model to estimate spatially distributed groundwater ages and flow directions within the Vollnkirchener Bach subcatchment. Our model revealed that complex age dynamics exist within the subcatchment and that much of the runoff must has been stored

  11. Simulating Groundwater-Plant-Atmosphere Interactions in a Semiarid Savanna

    NASA Astrophysics Data System (ADS)

    Gou, S.; Miller, G. R.

    2013-12-01

    Groundwater serves as one of the main water sources for deep rooted phreatophytic vegetation. Such vegetation acts as the linkage between groundwater, land surface and atmosphere. Through plant groundwater uptake and hydraulic redistribution (HR), the dynamics of relatively deep groundwater can influence ET and soil moisture of top soil layers. In this work, we first developed a plant scale model to simulate groundwater uptake and HR driven by the potential gradients along the groundwater-soil-plant-atmosphere continuum (GSPAC). The model included a new plant water stress function based on the 'vulnerability curve' theory in order to integrate the influences of both soil water and groundwater on transpiration. The model was calibrated and validated with measured ET, soil moisture, and leaf water potential data and was able to capture both energy and water dynamics along the GSPAC. We then coupled this plant scale model into a spatial distributed groundwater-land surface model (ParFlow.CLM). The revisions to ParFlow.CLM allow it to explicitly describe root water uptake and HR of different species, allowing for the study of how plant groundwater use and HR influence regional water budget and climate. This new uptake formulation was applied to simulate a heterogeneous savanna system at an AmeriFlux site in California. The site is dominated by blue oaks which can access both soil water and groundwater and grasses which only depend on soil water. The results match previous field measurements indicating that the oaks use most soil water during wet season and switch to groundwater use in dry season to buffer the impacts of drought. Therefore, the water and energy dynamics at this site showed the soil moisture controlled pattern in wet season, and the vegetation and groundwater controlled pattern in dry season. With HR, the rainfall is distributed into deeper soil in wet season by hydraulic descent. Such water will be lifted into shallower soil to promote transpiration in

  12. Clinical development of gene- and cell-based therapies: overview of the European landscape

    PubMed Central

    de Wilde, Sofieke; Guchelaar, Henk-Jan; Zandvliet, Maarten Laurens; Meij, Pauline

    2016-01-01

    In the last decade, many clinical trials with gene- and cell-based therapies were performed and increasing interest in the development was established by (national) authorities, academic developers, and commercial companies. However, until now only eight products have received marketing authorization (MA) approval. In this study, a comprehensive overview of the clinical development of gene- and cell-based therapies in Europe is presented, with a strong focus on product-technical aspects. Public data regarding clinical trials with gene- and cell-based therapies, obtained from the European Union (EU) clinical trial database (EudraCT) between 2004 and 2014 were analyzed, including product-technical variables as potential determinants affecting development. 198 unique gene and cell therapy products were identified, which were studied in 278 clinical trials, mostly in phase 1/2 trials and with cell therapies as major group. Furthermore, most products were manufactured from autologous starting material mostly manufactured from stem cells. The majority of the trials were sponsored by academia, whereas phase 3 trials mostly by large companies. Academia dominated early-stage development by mainly using bone marrow derived products and stem cells. Conversely, commercial sponsors were more actively pursuing in vivo gene therapy medicinal product development, and cell therapies derived from differentiated tissue in later-stage development. PMID:27990447

  13. Clinical development of gene- and cell-based therapies: overview of the European landscape.

    PubMed

    de Wilde, Sofieke; Guchelaar, Henk-Jan; Zandvliet, Maarten Laurens; Meij, Pauline

    2016-01-01

    In the last decade, many clinical trials with gene- and cell-based therapies were performed and increasing interest in the development was established by (national) authorities, academic developers, and commercial companies. However, until now only eight products have received marketing authorization (MA) approval. In this study, a comprehensive overview of the clinical development of gene- and cell-based therapies in Europe is presented, with a strong focus on product-technical aspects. Public data regarding clinical trials with gene- and cell-based therapies, obtained from the European Union (EU) clinical trial database (EudraCT) between 2004 and 2014 were analyzed, including product-technical variables as potential determinants affecting development. 198 unique gene and cell therapy products were identified, which were studied in 278 clinical trials, mostly in phase 1/2 trials and with cell therapies as major group. Furthermore, most products were manufactured from autologous starting material mostly manufactured from stem cells. The majority of the trials were sponsored by academia, whereas phase 3 trials mostly by large companies. Academia dominated early-stage development by mainly using bone marrow derived products and stem cells. Conversely, commercial sponsors were more actively pursuing in vivo gene therapy medicinal product development, and cell therapies derived from differentiated tissue in later-stage development.

  14. Effects of landscape-based green infrastructure on stormwater runoff in suburban developments

    EPA Science Inventory

    The development of impervious surfaces in urban and suburban catchments affects their hydrological behavior by decreasing infiltration, increasing peak hydrograph response following rainfall events, and ultimately increasing the total volume of water and mass of pollutants reachi...

  15. Pathology Residency Programme of a Developing Country--Landscape of Last 25 Years

    ERIC Educational Resources Information Center

    Siddiqui, Imran; Ali, Natasha; Kayani, Naila

    2016-01-01

    We report the evolution of a residency programme in Pathology from a developing country. This article highlights the historical perspective of our application procedure, the number of inductions, the programme framework, acheivements and limitations.

  16. Effects of landscape-based green infrastructure on stormwater runoff in suburban developments

    EPA Science Inventory

    The development of impervious surfaces in urban and suburban catchments affects their hydrological behavior by decreasing infiltration, increasing peak hydrograph response following rainfall events, and ultimately increasing the total volume of water and mass of pollutants reachi...

  17. Rill development, headcut migration, and sediment efflux from an evolving experimental landscape

    USDA-ARS?s Scientific Manuscript database

    Experiments were conducted using a soil-mantled flume subjected to simulated rain and downstream baselevel lowering to quantify the growth, development, and evolution of rills and rill networks. Digital elevation models constructed using photogrammetric techniques greatly facilitated data acquisiti...

  18. Landscapes, tourism, and conservation

    PubMed

    Burger

    2000-04-17

    One key aspect of global change is a decrease in ecological integrity as more and more landscapes are developed, leaving a mosaic of intact refuges and degraded patches that may not be sufficient for conserving biodiversity. While increases in human population and shifts in the distribution of people affect land use, the temporary movement of people can have major implications for conservation and biodiversity. Three examples are presented where recreation/tourism can enhance the conservation of land on a landscape scale, leading to habitat protection and biodiversity preservation: (1) Shorebirds often require a matrix of different habitat types during migratory stopovers, and ecotourism can serve as a catalyst for landscape scale protection of habitat. (2) Riparian habitats can serve as corridors to link diverse habitat patches, as well as serving as biodiversity hotspots. (3) Remediation and rehabilitation of contaminated lands, such as those of the US Department of Energy, aimed at developing recreational activities on the uncontaminated portions, can be the most economical form of re-development with no increase in human or ecological risk. Since large areas on many DOE sites have been undisturbed since the Second World War, when they were acquired, they contain unique or valuable ecosystems that serve an important role within their regional landscapes. In all three cases the judicious development of recreational/tourist interests can encourage both the conservation of habitats and the wise management of habitats on a landscape scale. While some species or habitats are too fragile for sustained tourism, many can be managed so that species, ecosystems and ecotourists flourish. By contributing to the economic base of regions, ecotourists/recreationists can influence the protection of land and biodiversity on a landscape scale, contributing to ecosystem management. The human dimensions of land preservation and biodiversity protection are key to long

  19. Disposable Landscapes

    Treesearch

    Kevin T. Smith

    2008-01-01

    Whether we are a traditionalist or on the cutting edge of landscape care, we need to take a deep breath and think about what we are trying to achieve, before we select a specific treatment or practice for tree care. We should measure that treatment or practice against what we know about the tree system. I say "system" because the recent years of Modern...

  20. Hillslope soil movement in the oak savannas of the Southwestern Borderlands Region

    Treesearch

    Aaron Kauffman

    2009-01-01

    Oak woodlands and savannas comprise more than 31,000 square miles (80,290 square kilometers) in the southwestern United States and northern Mexico and provide various resources including forage for livestock, wildlife habitat, fuelwood, and recreational areas. Increased woody-plant encroachment into the more open savanna ecosystems has presented a problem to managers...

  1. Songbirds in managed and non-managed savannas and woodlands in the central hardwoods region

    Treesearch

    Frank R., III Thompson; Jennifer L. Reidy; Sarah W. Kendrick; Jane A. Fitzgerald

    2012-01-01

    We know little about the response of birds to savanna and woodland restoration in the Ozarks or how important such habitats are to birds of conservation concern. Bird species such as red-headed woodpecker, prairie warbler, field sparrow, and blue-winged warbler are species of regional concern, and declines of these species may be due to historical declines in savannas...

  2. Spatial vegetation patterns and neighborhood competition among woody plants in an East African savanna

    USDA-ARS?s Scientific Manuscript database

    The majority of research on savanna vegetation dynamics has focused on the coexistence of woody and herbaceous vegetation; interactions among woody plants in savannas are relatively poorly understood. We present data from a 10-year longitudinal study of spatially explicit growth patterns of woody ve...

  3. Plant composition in oak savanna and woodland restoration at Prairie Fork Conservation Area in Missouri

    Treesearch

    Nadia E. Navarrete-Tindall; J.W. Van Sambeek; Jamie Coe; Warren. Taylor

    2007-01-01

    The wooded areas of the Prairie Fork Conservation Area in central Missouri are typical of the oak/hickory forest/prairie transition zone that will require active management to restore pre-settlement, grass dominated savannas and open woodlands to improve habitat for wildlife. We initiated a management program to restore savannas and woodlands by reducing the midstory (...

  4. Plant diversity and invasives in blue oak savannas of the southern Sierra Nevada

    Treesearch

    Jon E. Keeley

    2002-01-01

    Blue oak savannas were found to be substantially more diverse at all scales from localized point diversity to the community scale, than higher elevation shrubland and coniferous forests in the southern Sierra Nevada. Also, alien plants were more diverse and represented a substantial fraction of the understory flora in these blue oak savannas, comprising three-fourths...

  5. Stem and leaf hydraulics of congeneric tree species from adjacent tropical savanna and forest ecosystems

    Treesearch

    Guang You Hao; William A. Hoffmann; Fabian G. Scholz; Sandra J. Bucci; Frederick C. Meinzer; Augusto C. Franco; Kun Fang Cao; Guillermo Goldstein

    2008-01-01

    Leaf and stem functional traits related to plant water relations were studied for six congeneric species pairs, each composed of one tree species typical of savanna habitats and another typical of adjacent forest habitats, to determine whether there were intrinsic differences in plant hydraulics between these two functional types. Only individuals growing in savanna...

  6. Determinants of flammability in savanna grass species.

    PubMed

    Simpson, Kimberley J; Ripley, Brad S; Christin, Pascal-Antoine; Belcher, Claire M; Lehmann, Caroline E R; Thomas, Gavin H; Osborne, Colin P

    2016-01-01

    Tropical grasses fuel the majority of fires on Earth. In fire-prone landscapes, enhanced flammability may be adaptive for grasses via the maintenance of an open canopy and an increase in spatiotemporal opportunities for recruitment and regeneration. In addition, by burning intensely but briefly, high flammability may protect resprouting buds from lethal temperatures. Despite these potential benefits of high flammability to fire-prone grasses, variation in flammability among grass species, and how trait differences underpin this variation, remains unknown.By burning leaves and plant parts, we experimentally determined how five plant traits (biomass quantity, biomass density, biomass moisture content, leaf surface-area-to-volume ratio and leaf effective heat of combustion) combined to determine the three components of flammability (ignitability, sustainability and combustibility) at the leaf and plant scales in 25 grass species of fire-prone South African grasslands at a time of peak fire occurrence. The influence of evolutionary history on flammability was assessed based on a phylogeny built here for the study species.Grass species differed significantly in all components of flammability. Accounting for evolutionary history helped to explain patterns in leaf-scale combustibility and sustainability. The five measured plant traits predicted components of flammability, particularly leaf ignitability and plant combustibility in which 70% and 58% of variation, respectively, could be explained by a combination of the traits. Total above-ground biomass was a key driver of combustibility and sustainability with high biomass species burning more intensely and for longer, and producing the highest predicted fire spread rates. Moisture content was the main influence on ignitability, where species with higher moisture contents took longer to ignite and once alight burnt at a slower rate. Biomass density, leaf surface-area-to-volume ratio and leaf effective heat of combustion

  7. Reconciling Agricultural Needs with Biodiversity and Carbon Conservation in a Savanna Transformation Frontier

    NASA Astrophysics Data System (ADS)

    Spiegel, M. P.; Estes, L. D.; Caylor, K. K.; Searchinger, T.

    2015-12-01

    Zambia is a major hotspot for agricultural development in the African savannas, which will be targeted for agricultural expansion to relieve food shortages and economic insecurity in the next few decades. Recent scholarship rejects the assumption that the large reserves of arable land in the African savannas could be converted to cropland with low ecological costs. In light of these findings, the selection of land for agricultural expansion must consider not only its potential productivity, but also the increase in greenhouse gas emissions and biodiversity loss that would result from the land conversion. To examine these tradeoffs, we have developed a multi-objective optimization technique to seek scenarios for agricultural development in Zambia that simultaneously achieve production targets and minimize carbon, biodiversity, and economic cost constraints, while factoring in the inter-annual variability in crop production in this highly uncertain climate. Potential production is determined from well-characterized yield potential estimates while robust metrics of biodiversity and high resolution mapping of carbon storage provide fine scale estimates of ecological impact. We draw production targets for individual crops from potential development pathways, primarily export, commodity-crop driven expansion and identify ecologically responsible agricultural development scenarios that are resilient to climate change and meet these demands. In order to achieve a doubling of production of nine key crops, assuming a modest 20% overall increase in yield potential, we find a range of scenarios that use less than 1600 km2 of new land without infringing on any protected areas or exceeding 6.7 million tons of carbon emissions.

  8. Landscape development in an hyperarid sandstone environment along the margins of the Dead Sea fault: Implications from dated rock falls

    USGS Publications Warehouse

    Matmon, A.; Shaked, Y.; Porat, N.; Enzel, Y.; Finkel, R.; Lifton, N.; Boaretto, E.; Agnon, A.

    2005-01-01

    In this study, we explored the spatial and temporal relations between boulders and their original in-situ locations on sandstone bedrock cliffs. This was accomplished by combining field observations with dating methods using cosmogenic isotopes (10Be and 14C) and optically stimulated luminescence (OSL). Our conclusions bear both on the landscape evolution and cliff retreat process in the hyperarid region of Timna and on the methodology of estimating exposure ages using cosmogenic isotopes. We recognize three discrete rock fall events, at 31 ka, 15 ka, and 4 ka. In this hyperarid region, the most plausible triggering mechanism for rock fall events is strong ground acceleration caused by earthquakes generated by the nearby Dead Sea fault (DSF). Our record, however, under represents the regional earthquake record implying that ongoing development of detachment cracks prior to the triggering event might be slower than the earthquake cycle. Cliff retreat rates calculated using the timing of rock fall events and estimated thickness of rock removed in each event range between 0.14 m ky-1 and 2 m ky-1. When only full cycles are considered, we derive a more realistic range of 0.4 m ky-1 to 0.7 m ky-1. These rates are an order of magnitude faster than the calculated rate of surface lowering in the area. We conclude that sandstone cliffs at Timna retreat through episodic rock fall events that preserve the sharp, imposing, landscape characteristic to this region and that ongoing weathering of the cliff faces is minor. A 10%-20% difference in the 10Be concentrations in samples from matching boulder and cliff faces that have identical exposure histories and are located only a few meters apart indicates that cosmogenic nuclide production rates are sensitive to shielding and vary spatially over short distances. However, uncertainties associated with age calculations yielded boulder and matching cliff face ages that are similar within 1 ??. The use of external constraints in the

  9. Obstacles to Enhancing Professional Development with Digital Tools in Rural Landscapes

    ERIC Educational Resources Information Center

    Hunt-Barron, Sarah; Tracy, Kelly N.; Howell, Emily; Kaminski, Rebecca

    2015-01-01

    This case study examines the use of online tools, including blogs, as a means of enhancing face-to-face professional development in writing instruction for teachers in rural districts. Since many rural districts serve large physical areas that are geographically distant from larger metropolitan areas and/or colleges and universities, teachers in…

  10. MID-ATLANTIC COASTAL STREAMS STUDY: STATISTICAL DESIGN FOR REGIONAL ASSESSMENT AND LANDSCAPE MODEL DEVELOPMENT

    EPA Science Inventory

    A network of stream-sampling sites was developed for the Mid-Atlantic Coastal Plain (New Jersey through North Carolina) as part of collaborative research between the U.S. Environmental Protection Agency and the U.S. Geological Survey. A stratified random sampling with unequal wei...

  11. The Federal Policy Landscape: A Look at How Legislation Affects Professional Development

    ERIC Educational Resources Information Center

    Islas, M. Rene

    2010-01-01

    Four years ago, Learning Forward established "affecting the policy context" as the first of five strategic priorities that would guide its efforts through 2011. Learning Forward believes that good policy promotes good practice and that laws and policies that promote and support effective professional development are needed to achieve the…

  12. Developing probabilistic models to predict amphibian site occupancy in a patchy landscape

    Treesearch

    R. A. Knapp; K.R. Matthews; H. K. Preisler; R. Jellison

    2003-01-01

    Abstract. Human-caused fragmentation of habitats is threatening an increasing number of animal and plant species, making an understanding of the factors influencing patch occupancy ever more important. The overall goal of the current study was to develop probabilistic models of patch occupancy for the mountain yellow-legged frog (Rana muscosa). This once-common species...

  13. The Federal Policy Landscape: A Look at How Legislation Affects Professional Development

    ERIC Educational Resources Information Center

    Islas, M. Rene

    2010-01-01

    Four years ago, Learning Forward established "affecting the policy context" as the first of five strategic priorities that would guide its efforts through 2011. Learning Forward believes that good policy promotes good practice and that laws and policies that promote and support effective professional development are needed to achieve the…

  14. Development of a Multi-Hazard Landscape for Exposure and Risk Interpretation

    EPA Science Inventory

    A complete accounting of potential hazard exposures is critical in the development of any model meant to depict the resilience of a system. This allows for a clear ledger to both assess current risk status along with potential ways to improve resilience. The US EPA is currently...

  15. MID-ATLANTIC COASTAL STREAMS STUDY: STATISTICAL DESIGN FOR REGIONAL ASSESSMENT AND LANDSCAPE MODEL DEVELOPMENT

    EPA Science Inventory

    A network of stream-sampling sites was developed for the Mid-Atlantic Coastal Plain (New Jersey through North Carolina) a collaborative study between the U.S. Environmental Protection Agency and the U.S. Geological Survey. A stratified random sampling with unequal weighting was u...

  16. The social aspects of landscape change: protecting open space under the pressure of development

    Treesearch

    Paul H. Gobster; Susan I. Stewart; David N. Bengston

    2004-01-01

    The extent of developed land in many parts of the world has increased rapidly in recent decades, posing significant challenges to the protection of forests, agricultural lands, and other natural and culturally modified green areas in urban and rural settings. Sustaining these open spaces has long been seen as a critical issue economically, and it is now increasingly...

  17. Development of a Multi-Hazard Landscape for Exposure and Risk Interpretation

    EPA Science Inventory

    A complete accounting of potential hazard exposures is critical in the development of any model meant to depict the resilience of a system. This allows for a clear ledger to both assess current risk status along with potential ways to improve resilience. The US EPA is currently...

  18. MID-ATLANTIC COASTAL STREAMS STUDY: STATISTICAL DESIGN FOR REGIONAL ASSESSMENT AND LANDSCAPE MODEL DEVELOPMENT

    EPA Science Inventory

    A network of stream-sampling sites was developed for the Mid-Atlantic Coastal Plain (New Jersey through North Carolina) as part of collaborative research between the U.S. Environmental Protection Agency and the U.S. Geological Survey. A stratified random sampling with unequal wei...

  19. MID-ATLANTIC COASTAL STREAMS STUDY: STATISTICAL DESIGN FOR REGIONAL ASSESSMENT AND LANDSCAPE MODEL DEVELOPMENT

    EPA Science Inventory

    A network of stream-sampling sites was developed for the Mid-Atlantic Coastal Plain (New Jersey through North Carolina) a collaborative study between the U.S. Environmental Protection Agency and the U.S. Geological Survey. A stratified random sampling with unequal weighting was u...

  20. Geomorpho-Landscapes

    NASA Astrophysics Data System (ADS)

    Farabollini, Piero; Lugeri, Francesca; Amadio, Vittorio

    2014-05-01

    Landscape is the object of human perceptions, being the image of spatial organization of elements and structures: mankind lives the first approach with the environment, viewing and feeling the landscape. Many definitions of landscape have been given over time: in this case we refer to the Landscape defined as the result of interaction among physical, biotic and anthropic phenomena acting in a different spatial-temporal scale (Foreman & Godron) Following an Aristotelic approach in studying nature, we can assert that " Shape is synthesis": so it is possible to read the land features as the expression of the endogenous and exogenous processes that mould earth surfaces; moreover, Landscape is the result of the interaction of natural and cultural components, and conditions the spatial-temporal development of a region. The study of the Landscape offers results useful in order to promote sustainable development, ecotourism, enhancement of natural and cultural heritage, popularization of the scientific knowledge. In Italy, a very important GIS-based tool to represent the territory is the "Carta della Natura" ("Map of Nature", presently coordinated by the ISPRA) that aims at assessing the state of the whole Italian territory, analyzing Landscape. The methodology follows a holistic approach, taking into consideration all the components of a landscape and then integrating the information. Each individual landscape, studied at different scales, shows distinctive elements: structural, which depend on physical form and specific spatial organization; functional, which depend on relationships created between biotic and abiotic elements, and dynamic, which depend on the successive evolution of the structure. The identification of the landscape units, recognized at different scales of analysis, allows an evaluation of the state of the land, referring to the dual risk/resource which characterizes the Italian country. An interesting opportunity is to discover those areas of unusual

  1. Creating a fuels baseline and establishing fire frequency relationships to develop a landscape management strategy at the Savannah River Site.

    SciTech Connect

    Parresol, Bernard R; Shea, Dan; Ottmar, Roger

    2006-03-15

    USDA Forest Service Proceedings RMRS-P-41. pp 351-366. Abstract—The Savannah River Site is a Department of Energy Nuclear Defense Facility and a National Environmental Research Park located in the upper coastal plain of South Carolina. Prescribed burning is conducted on 15,000 to 20,000 ac annually. We modifi ed standard forest inventory methods to incorporate a complete assessment of fuel components on 622 plots, assessing coarse woody debris, ladder fuels, and the litter and duff layers. Because of deficiencies in south-wide data on litter-duff bulk densities, which are the fuels most often consumed in prescribed fires, we developed new bulk density relationships. Total surface fuel loading across the landscape ranged from 0.8 to 48.7 tons/ac. The variables basal area, stand age, and site index were important in accounting for variability in ladder fuel, coarse woody debris, and litter-duff for pine types. For a given pine stand condition, litter-duff loading decreased in direct proportion to the number of burns in the preceding thirty years. Ladder fuels for loblolly and longleaf increased in direct proportion to the years since the last prescribed burn. The pattern of fuel loading on the SRS reflects stand dynamics, stand management and fire management. It is suggested that the Forest Inventory and Analysis Program can easily modify sampling protocols to incorporate collection of fuels data.

  2. Emotional learning, stress, and development: An ever-changing landscape shaped by early-life experience.

    PubMed

    Pattwell, Siobhan S; Bath, Kevin G

    2017-09-01

    The capacity to learn to associate cues with negative outcomes is a highly adaptive process that appears to be conserved across species. However, when the cue is no longer a valid predictor of danger, but the emotional response persists, this can result in maladaptive behaviors, and in humans contribute to debilitating emotional disorders. Over the past several decades, work in neuroscience, psychiatry, psychology, and biology have uncovered key processes underlying, and structures governing, emotional responding and learning, as well as identified disruptions in the structural and functional integrity of these brain regions in models of pathology. In this review, we highlight some of this elegant body of work as well as incorporate emerging findings from the field of developmental neurobiology to emphasize how development contributes to changes in the ability to learn and express emotional responses, and how early experiences, such as stress, shape the development and functioning of these circuits. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Combining laser microdissection and RNA-seq to chart the transcriptional landscape of fungal development

    PubMed Central

    2012-01-01

    Background During sexual development, filamentous ascomycetes form complex, three-dimensional fruiting bodies for the protection and dispersal of sexual spores. Fruiting bodies contain a number of cell types not found in vegetative mycelium, and these morphological differences are thought to be mediated by changes in gene expression. However, little is known about the spatial distribution of gene expression in fungal development. Here, we used laser microdissection (LM) and RNA-seq to determine gene expression patterns in young fruiting bodies (protoperithecia) and non-reproductive mycelia of the ascomycete Sordaria macrospora. Results Quantitative analysis showed major differences in the gene expression patterns between protoperithecia and total mycelium. Among the genes strongly up-regulated in protoperithecia were the pheromone precursor genes ppg1 and ppg2. The up-regulation was confirmed by fluorescence microscopy of egfp expression under the control of ppg1 regulatory sequences. RNA-seq analysis of protoperithecia from the sterile mutant pro1 showed that many genes that are differentially regulated in these structures are under the genetic control of transcription factor PRO1. Conclusions We have generated transcriptional profiles of young fungal sexual structures using a combination of LM and RNA-seq. This allowed a high spatial resolution and sensitivity, and yielded a detailed picture of gene expression during development. Our data revealed significant differences in gene expression between protoperithecia and non-reproductive mycelia, and showed that the transcription factor PRO1 is involved in the regulation of many genes expressed specifically in sexual structures. The LM/RNA-seq approach will also be relevant to other eukaryotic systems in which multicellular development is investigated. PMID:23016559

  4. Research needs for our national landscapes

    Treesearch

    Elwood L. Shafer

    1979-01-01

    The prevailing research problem for our national landscapes is: How shall we organize, control, and coordinate public and private development so as to protect, maintain, improve, and manage those landscape features that we value most? Research questions discussed include: environmental/political conflicts, taxation and zoning, landscape classification, public...

  5. Ecosystem services in changing landscapes: An introduction

    Treesearch

    Louis Iverson; Cristian Echeverria; Laura Nahuelhual; Sandra. Luque

    2014-01-01

    The concept of ecosystem services from landscapes is rapidly gaining momentum as a language to communicate values and benefits to scientists and lay alike. Landscape ecology has an enormous contribution to make to this field, and one could argue, uniquely so. Tools developed or adapted for landscape ecology are being increasingly used to assist with the quantification...

  6. Understory plant communities and the functional distinction between savanna trees, forest trees, and pines.

    PubMed

    Veldman, Joseph W; Mattingly, W Brett; Brudvig, Lars A

    2013-02-01

    Although savanna trees and forest trees are thought to represent distinct functional groups with different effects on ecosystem processes, few empirical studies have examined these effects. In particular, it remains unclear if savanna and forest trees differ in their ability to coexist with understory plants, which comprise the majority of plant diversity in most savannas. We used structural equation modeling (SEM) and data from 157 sites across three locations in the southeastern United States to understand the effects of broadleaf savanna trees, broadleaf forest trees, and pine trees on savanna understory plant communities. After accounting for underlying gradients in fire frequency and soil moisture, abundances (i.e., basal area and stem density) of forest trees and pines, but not savanna trees, were negatively correlated with the cover and density (i.e., local-scale species richness) of C4 graminoid species, a defining savanna understory functional group that is linked to ecosystem flammability. In analyses of the full understory community, abundances of trees from all functional groups were negatively correlated with species density and cover. For both the C4 and full communities, fire frequency promoted understory plants directly, and indirectly by limiting forest tree abundance. There was little indirect influence of fire on the understory mediated through savanna trees and pines, which are morefire tolerant than forest trees. We conclude that tree functional identity is an important factor that influences overstory tree relationships with savanna understory plant communities. In particular, distinct relationships between trees and C4 graminoids have implications for grass-tree coexistence and vegetation-fire feedbacks that maintain savanna environments and their associated understory plant diversity.

  7. Understory plant communities and the functional distinction between savanna trees, forest trees, and pines

    SciTech Connect

    Veldman, Joseph W.; Mattingly, W. Brett; Brudvig, Lars A.

    2013-02-01

    Although savanna trees and forest trees are thought to represent distinct functional groups with different effects on ecosystem processes, few empirical studies have examined these effects. In particular, it remains unclear if savanna and forest trees differ in their ability to coexist with understory plants, which comprise the majority of plant diversity in most savannas. We used structural equation modeling (SEM) and data from 157 sites across three locations in the southeastern United States to understand the effects of broadleaf savanna trees, broadleaf forest trees, and pine trees on savanna understory plant communities. After accounting for underlying gradients in fire frequency and soil moisture, abundances (i.e., basal area and stem density) of forest trees and pines, but not savanna trees, were negatively correlated with the cover and density (i.e., local-scale species richness) of C4 graminoid species, a defining savanna understory functional group that is linked to ecosystem flammability. In analyses of the full understory community, abundances of trees from all functional groups were negatively correlated with species density and cover. For both the C4 and full communities, fire frequency promoted understory plants directly, and indirectly by limiting forest tree abundance. There was little indirect influence of fire on the understory mediated through savanna trees and pines, which are more fire tolerant than forest trees. We conclude that tree functional identity is an important factor that influences overstory tree relationships with savanna understory plant communities. In particular, distinct relationships between trees and C4 graminoids have implications for grass-tree coexistence and vegetation-fire feedbacks that maintain savanna environments and their associated understory plant diversity.

  8. The Impact of Fire on Energy Balance in Southern African Savanna Ecosystems: Implications of Climate Change

    NASA Astrophysics Data System (ADS)

    Dintwe, K.; Okin, G. S.; Saha, M.; Scanlon, T. M.; D'Odorico, P.; De Sales, F.; Xue, Y.

    2015-12-01

    Savannas are the most fire prone ecosystems in the world accounting for more than 75% of annual global fires. Wildfires in savannas consume large quantities of biomass releasing CO2 and aerosols while leaving ash and char residues. The residues form black-grey patches on the soil surface, and together with newly exposed bare soil patches, they play a significant role in altering surface reflectance and vegetation condition. We investigated the impact of fire on savanna albedo and vegetation greenness (from Enhanced Vegetation Index, EVI) from 2000-2014 using data from the Moderate Resolution Imaging Spectrometer (MODIS) for Africa south of the Equator. Preliminary results indicate that more mesic savannas near the Equator have the highest fire frequencies, with fire frequency generally decreasing with aridity. Immediately after fires, the average change in albedo and EVI is -5% and -10%, respectively, with the magnitude of the change increasing with aridity. The time for albedo to recover to values similar to unburned areas varied by latitude, with more mesic savannas recovering much faster (24 days vs. 65 days for dry savannas). The time for vegetation condition to recover did not vary strongly by latitude (about 65 days). The upward shortwave energy in burnt areas in mesic savannas is 53 W m-2 compared to 95 W m-2 for unburnt areas, indicating a positive forcing of about 42 W m-2 associated with mesic savanna fires locally. Approximately 7% of the (primarily savanna) land in southern Africa burns each year, suggesting an overall forcing in Africa south of the Equator of ~1-2 W m-2 associated with savanna fires. This large forcing indicates clearly the important interplay between ecosystem processes (fire) and climate (radiative forcing) in this region. With changing climate, this region is expected to become significantly drier, suggesting that the forcing due to fire might decrease in the coming decades and indicating that fire-induced albedo changes potentially

  9. Development and evolution of the amniote integument: current landscape and future horizon.

    PubMed

    Chuong, Cheng-Ming; Homberger, Dominique G

    2003-08-15

    This special issue on the development and evolution of the amniote integument begins with a discussion of the adaptations to terrestrial conditions, the acquisition of water-impermeability of the reptilian integument, and the initial formation of filamentous integumentary appendages that prepare the way towards avian flight. Recent feather fossils are reviewed, and a definition of feathers is developed. Hierarchical models are proposed for the formation of complex structures, such as feathers. Molecular signals that alter the phenotype of integumentary appendages at different levels of the hierarchy are presented. Tissue interactions and the roles of keratins in evolution are discussed and linked to their bio-mechanical properties. The role of mechanical forces on patterning is explored. Elaborate extant feather variants are introduced. The regeneration/gene mis-expression protocol for the chicken feather is established as a testable model for the study of biological structures. The adaptations of the mammalian distal limb end organs to terrestrial, arboreal and aquatic conditions are discussed. The development and cycling of hair are reviewed from a molecular perspective. These contributions reveal that the structure and function of diverse integumentary appendages are variations that are superimposed on a common theme, and that their formation is modular, hierarchical and cyclical. They further reveal that these mechanisms can be understood at the molecular level, and that an integrative and organismal approach to studying integumentary appendages is called for. We propose that future research should foster interdisciplinary approaches, pursue understanding at the cellular and molecular level, analyze interactions between the environment and genome, and recognize the contributions of variation in morphogenesis and evolution. Copyright 2003 Wiley-Liss, Inc.

  10. Development and Evolution of the Amniote Integument: Current Landscape and Future Horizon

    PubMed Central

    CHUONG, CHENG-MING; HOMBERGER, DOMINIQUE G.

    2015-01-01

    This special issue on the development and evolution of the amniote integument begins with a discussion of the adaptations to terrestrial conditions, the acquisition of water-impermeability by the reptilian integument, and the initial formation of filamentous integumentary appendages that pave the way towards avian flight. Recent feather fossils are reviewed and a definition of feathers is developed. Hierarchical models are proposed for the formation of complex structures, such as feathers. Molecular signals that alter the phenotype of integumentary appendages at different levels of the hierarchy are presented. Tissue interactions and the roles of keratins in evolution are discussed and linked to their bio-mechanical properties. The role of mechanical forces on patterning is explored. Elaborate extant feather variants are introduced. The regeneration/gene mis-expression protocol for the chicken feather is established as a testable model for the study of biological structures. The adaptations of the mammalian distal limb end organs to terrestrial, arboreal and aquatic conditions are discussed. The development and cycling of hair are reviewed from a molecular perspective. These contributions reveal that the structure and function of diverse integumentary appendages are variations superimposed on a common theme, and that their formation is modular, hierarchical, and cyclical. They further reveal that these mechanisms can be understood at the molecular level, and that an integrative and organismal approach to studying integumentary appendages is needed. We propose that future research should foster interdisciplinary approaches, pursue understanding at the cellular and molecular level, analyze interactions between the environment and genome, and recognize the contributions of variation in morphogenesis and evolution. PMID:12949766

  11. The changing landscape of membrane protein structural biology through developments in electron microscopy

    PubMed Central

    Rawson, Shaun; Davies, Simon; Lippiat, Jonathan D.; Muench, Stephen P.

    2016-01-01

    Abstract Membrane proteins are ubiquitous in biology and are key targets for therapeutic development. Despite this, our structural understanding has lagged behind that of their soluble counterparts. This review provides an overview of this important field, focusing in particular on the recent resurgence of electron microscopy (EM) and the increasing role it has to play in the structural studies of membrane proteins, and illustrating this through several case studies. In addition, we examine some of the challenges remaining in structural determination, and what steps are underway to enhance our knowledge of these enigmatic proteins. PMID:27608730

  12. 2015 RAD-AID Conference on International Radiology for Developing Countries: The Evolving Global Radiology Landscape.

    PubMed

    Kesselman, Andrew; Soroosh, Garshasb; Mollura, Daniel J

    2016-09-01

    Radiology in low- and middle-income (developing) countries continues to make progress. Research and international outreach projects presented at the 2015 annual RAD-AID conference emphasize important global themes, including (1) recent slowing of emerging market growth that threatens to constrain the advance of radiology, (2) increasing global noncommunicable diseases (such as cancer and cardiovascular disease) needing radiology for detection and management, (3) strategic prioritization for pediatric radiology in global public health initiatives, (4) continuous expansion of global health curricula at radiology residencies and the RAD-AID Chapter Network's participating institutions, and (5) technologic innovation for recently accelerated implementation of PACS in low-resource countries. Published by Elsevier Inc.

  13. Landscape analysis software tools

    Treesearch

    Don Vandendriesche

    2008-01-01

    Recently, several new computer programs have been developed to assist in landscape analysis. The “Sequential Processing Routine for Arraying Yields” (SPRAY) program was designed to run a group of stands with particular treatment activities to produce vegetation yield profiles for forest planning. SPRAY uses existing Forest Vegetation Simulator (FVS) software coupled...

  14. Landscape Management: Field Operator.

    ERIC Educational Resources Information Center

    Smith, Carole A.

    These materials for a six-unit course were developed to prepare secondary and postsecondary students for entry-level positions in landscape management. The six units are on orientation, hand tools, light power equipment, water and watering techniques, planting and maintaining plant beds, and establishing and maintaining turf. The first section is…

  15. A landscape analysis plan

    Treesearch

    Nancy E. Fleenor

    2002-01-01

    A Landscape Analysis Plan (LAP) sets out broad guidelines for project development within boundaries of the Kings River Sustainable Forest Ecosystems Project. The plan must be a dynamic, living document, subject to change as new information arises over the course of this very long-term project (several decades). Two watersheds, each of 32,000 acres, were dedicated to...

  16. Performance Technology Landscape.

    ERIC Educational Resources Information Center

    Addison, Roger M.

    2003-01-01

    Describes a performance technology landscape that has been developed for performance improvement institutes. Defines performance technology, including identification of value; definition of outcomes; performance analysis; valuation of effectiveness; focusing on results; systemic approach; adding value; aligning workers, activity, the organization,…

  17. Landscapes of Learning.

    ERIC Educational Resources Information Center

    Greene, Maxine

    The commitment of educators to human development goals is a major theme of the booklet's 17 essays. Compiled from lectures written by the author during 1974-77, the essays explore individual potential, the cultural significance of various life situations, and personal fulfillment within each individual's particular landscape of work, experience,…

  18. The changing landscape of functional brain networks for face processing in typical development

    PubMed Central

    Joseph, Jane E.; Swearingen, Joshua E.; Clark, Jonathan D.; Benca, Chelsie E.; Collins, Heather R.; Corbly, Christine R.; Gathers, Ann D.; Bhatt, Ramesh S.

    2012-01-01

    Greater expertise for faces in adults than in children may be achieved by a dynamic interplay of functional segregation and integration of brain regions throughout development. The present study examined developmental changes in face network functional connectivity in children (5–12 years) and adults (18–43 years) during face-viewing using a graph-theory approach. A face-specific developmental change involved connectivity of the right occipital face area (ROFA). During childhood, this node increased in strength and within-module clustering based on positive connectivity. These changes reflect an important role of the ROFA in segregation of function during childhood. In addition, strength and diversity of connections within a module that included primary visual areas (left and right calcarine) and limbic regions (left hippocampus and right inferior orbitofrontal cortex) increased from childhood to adulthood, reflecting increased visuo-limbic integration. This integration was pronounced for faces but also emerged for natural objects. Taken together, the primary face-specific developmental changes involved segregation of a posterior visual module during childhood, possibly implicated in early stage perceptual face processing, and greater integration of visuo-limbic connections from childhood to adulthood, which may reflect processing related to development of perceptual expertise for individuation of faces and other visually homogenous categories. PMID:22906788

  19. Comparison of Infiltrability Measurements in the Thornbush Savanna, Namibia

    NASA Astrophysics Data System (ADS)

    Classen, Nikolaus; Gröngröft, Alexander; Eschenbach, Annette

    2010-05-01

    Large proportions of Namibian Savannas are affected by strong bush encroachment leading to a reduction in grazing capacity. Especially woody plant encroachment is expected to have an impact on hydrology by increasing plant transpiration, bare soil evaporation and reducing soil water availability (HUXMAN et al. 2005). Although the processes are not fully understood, the role of soil water balance is highlighted by many studies. Especially the small-scale interactions of vegetation and soil are of high relevance. To characterize the water balance of different sites in the Namibian thornbush savanna long-term studies were conducted. In addition we applied three methods to quantify the infiltration rate (IR) at four central Namibian thornbush savanna sites differing in soil texture and vegetation type: a single ring (own construction, 14 cm inner diameter), a disc-infiltrometer (Eijkelkamp Agrisearch Equipment BV) and a hood infiltrometer (UGT Umwelt-Geräte-Technik GmbH). At each site, the measurements we conducted along short transect lines (15 m) in positions with differing plant influence (canopy of Acacia trees and shrubs, grass and dwarf-shrub tussocks, bare soil, termitaria). All three methods resulted in different mean IR as well as spatial distribution patterns. Using statistical analysis by ANOVA, dominant controlling variables were elaborated. The poster will demonstrate which of the methods is defensible with respect to the research question. References : HUXMAN, T. E., B. P. WILCOX, et al. (2005): Ecohydrological implications of woody plant encroachment. Ecology 86(2): 308-319. Acknowledgment: The work was founded by BMBF within the Project Biota South (support code 01LC 0624 A2).

  20. North African savanna fires and atmospheric carbon dioxide

    SciTech Connect

    Iacobellis, S.F.; Frouni, Razafimpaniolo, H.

    1994-04-20

    The effect of north African savanna fires on atmospheric CO{sub 2} is investigated using a tracer transport model. The model uses winds from operational numerical weather prediction analyses and provides CO{sub 2} concentrations as a function of space and time. After a spin-up period of several years, biomass-burning sources are added, and model experiments are run for an additional year, utilizing various estimates of CO{sub 2} sources. The various model experiments show that biomass burning in the north African savannas significantly affects CO{sub 2} concentrations in South America. The effect is more pronounced during the period from January through March, when biomass burning in South America is almost nonexistent. During this period, atmospheric CO{sub 2} concentrations in parts of South America typically may increase by 0.5 to 0.75 ppm at 970 mbar, the average pressure of the lowest model layer. These figures are above the probable uncertainty level, as model runs with biomass-burning sources estimated from independent studies using distinct data sets and techniques indicate. From May through September, when severe biomass burning occurs in South America, the effect of north African savanna fires over South America has become generally small at 970 mbar, but north of the equator it may be of the same magnitude or larger than the effect of South American fires. The CO{sub 2} concentration increase in the extreme northern and southern portions of South America, however, is mostly due to southern African fires, whose effect may be 2-3 times larger than the effect of South American fires at 970 mbar. Even in the central part of the continent, where local biomass-burning emissions are maximum, southern African fires contribute to at least 15% of the CO{sub 2} concentration increase at 970 mbar. 20 refs., 15 figs., 1 tab.

  1. Size characterization of dissolved metals and organic matter in source waters to streams in developed landscapes.

    PubMed

    Luan, Hongwei; Vadas, Timothy M

    2015-02-01

    Individual and mixed water samples from wastewater treatment plant effluents, stormwater runoff, streams from developed areas were characterized with respect to organic matter concentration and spectral properties and metal concentration and size distribution. In addition, asymmetric flow-field flow fractionation coupled to inductively coupled plasma mass spectrometry was used to measure concentration, size distribution and association of metals in the colloidal size range. Results reveal that Fe, Cu, Zn and Pb in the colloidal size range were mainly associated with the less than 5 nm, or less than 10 kDa size range. Cu was most strongly associated with organic matter, while Zn and Pb were mixed between Fe and organic matter. Effluent showed higher binding capacity for metals, while stormwater, even with higher organic matter concentrations showed more exchangeable metals. Upon mixing of source waters, colloidal metal concentrations and size distributions were conserved.

  2. Landscape Analysis of Nutrition-sensitive Agriculture Policy Development in Senegal.

    PubMed

    Lachat, Carl; Nago, Eunice; Ka, Abdoulaye; Vermeylen, Harm; Fanzo, Jessica; Mahy, Lina; Wüstefeld, Marzella; Kolsteren, Patrick

    2015-06-01

    Unlocking the agricultural potential of Africa offers a genuine opportunity to address malnutrition and drive development of the continent. Using Senegal as a case study, to identify gaps and opportunities to strengthen agricultural policies with nutrition-sensitive approaches. We carried out a systematic analysis of 13 policy documents that related to food production, agriculture, food security, or nutrition. Next, we collected data during a participatory analysis with 32 national stakeholders and in-depth interviews with 15 national experts of technical directorates of the different ministries that deal with agriculture and food production. The current agricultural context has various elements that are considered to enhance its nutrition sensitivity. On average, 8.3 of the 17 Food and Agriculture Organization guiding principles for agriculture programming for nutrition were included in the policies reviewed. Ensuring food security and increasing dietary diversity were considered to be the principal objectives of agricultural policies. Although there was considerable agreement that agriculture can contribute to nutrition, current agricultural programs generally do not target communities on the basis of their nutritional vulnerability. Agricultural programs were reported to have specific components to target female beneficiaries but were generally not used as delivery platforms for nutritional interventions. The findings of this study indicate the need for a coherent policy environment across the food system that aligns recommendations at the national level with local action on the ground. In addition, specific activities are needed to develop a shared understanding of nutrition and public health nutrition within the agricultural community in Senegal. © The Author(s) 2015.

  3. Age and dynamics of the Namib Sand Sea: A review of chronological evidence and possible landscape development models

    NASA Astrophysics Data System (ADS)

    Stone, A. E. C.

    2013-06-01

    The Namib Sand Sea constitutes a major physiographic feature of the Namib Desert on the west of Namibia, covering a 50-160 km wide region of the coast between Lüderitz and Walvis Bay. It is widely considered to be one of the oldest desert regions, with a Tertiary-aged fossil desert underlying the modern sand sea. The sand sea has been well studied, benefiting from the presence of the Gobabeb Training and Research Centre during the past 50 years. Whilst much is understood about its sediments and geomorphology, it is only recently that new chronological information, using cosmogenic-nuclide burial dating and optically stimulated luminescence dating have offered new insights, and this calls for an updated review of the age and landscape development of the sand sea. This assessment of the geomorphological and Quaternary dynamics of the region is complemented by developments in the description and analysis of sediment composition. New age control from cosmogenic dating indicates that the sand sea is in excess of a million years old. Initial data from luminescence dating yields depositional ages for dune sediments from three broad areas of the sand sea that include MIS 5, later in the Pleistocene around the Last Glacial Maximum and the Holocene, although it is not expected that these will be the only, or discrete age groupings. Detailed dating and application of ground penetrating radar in the far northern reaches reveals extensive dune migration and deposition during the Holocene. It is important to stress that the upper limit of luminescence dating here is about ˜200 ka (depending on the environmental dose rate of the site) and that migration and reworking of dunes resets the luminescence signal (so what is recorded is(are) the last phase(s) of preserved sediment accumulation). Whilst there are three potential sources of material for the Namib Sand Sea (reworked Tsondab Sandstone (TSS), material from the Great Escarpment derived by rivers and water and wind

  4. Effectiveness of scat-detection dogs in determining species presence in a tropical savanna landscape.

    PubMed

    Vynne, Carly; Skalski, John R; Machado, Ricardo B; Groom, Martha J; Jácomo, Anah T A; Marinho-Filho, Jader; Ramos Neto, Mario B; Pomilla, Cristina; Silveira, Leandro; Smith, Heath; Wasser, Samuel K

    2011-02-01

    Most protected areas are too small to sustain populations of wide-ranging mammals; thus, identification and conservation of high-quality habitat for those animals outside parks is often a high priority, particularly for regions where extensive land conversion is occurring. This is the case in the vicinity of Emas National Park, a small protected area in the Brazilian Cerrado. Over the last 40 years the native vegetation surrounding the park has been converted to agriculture, but the region still supports virtually all of the animals native to the area. We determined the effectiveness of scat-detection dogs in detecting presence of five species of mammals threatened with extinction by habitat loss: maned wolf (Chrysocyon brachyurus), puma (Puma concolor), jaguar (Panthera onca), giant anteater (Myrmecophaga tridactyla), and giant armadillo (Priodontes maximus). The probability of scat detection varied among the five species and among survey quadrats of different size, but was consistent across team, season, and year. The probability of occurrence, determined from the presence of scat, in a randomly selected site within the study area ranged from 0.14 for jaguars, which occur primarily in the forested areas of the park, to 0.91 for maned wolves, the most widely distributed species in our study area. Most occurrences of giant armadillos in the park were in open grasslands, but in the agricultural matrix they tended to occur in riparian woodlands. At least one target species occurred in every survey quadrat, and giant armadillos, jaguars, and maned wolves were more likely to be present in quadrats located inside than outside the park. The effort required for detection of scats was highest for the two felids. We were able to detect the presence for each of five wide-ranging species inside and outside the park and to assign occurrence probabilities to specific survey sites. Thus, scat dogs provide an effective survey tool for rare species even when accurate detection likelihoods are required. We believe the way we used scat-detection dogs to determine the presence of species can be applied to the detection of other mammalian species in other ecosystems.

  5. Fires in tropical savanna ecosystems -- The need for mitigation?

    SciTech Connect

    Ward, D.E.; Shea, R.; Hao, W.M.

    1994-12-31

    Fires in savanna ecosystems are usually considered to be ``natural`` in that the ecosystems where fire is present generally have evolved in the presence of fire. In the past several decades, with large increases in population in most of the tropical countries, there has been an accelerated demand for fuel wood, charcoal, building materials, and agriculture. The overall effect has been to reduce the above-ground biomass and to cycle the carbon more frequently. The authors discuss the mitigation strategies for reducing the release of carbon from charcoal production and shifting cultivation.

  6. North African savanna fires and atmospheric carbon dioxide

    NASA Technical Reports Server (NTRS)

    Iacobellis, Sam F.; Frouin, Robert; Razafimpanilo, Herisoa; Somerville, Richard C. J.; Piper, Stephen C.

    1994-01-01

    The effect of north African savanna fires on atmospheric CO2 is investigated using a tracer transport model. The model uses winds from operational numerical weather prediction analyses and provides CO2 concentrations as a function of space and time. After a spin-up period of several years, biomass-burning sources are added, and model experiments are run for an additional year, utilizing various estimates of CO2 sources. The various model experiments show that biomass burning in the north African savannas significantly affects CO2 concentrations in South America. The effect is more pronounced during the period from January through March, when biomass burning in South America is almost nonexistent. During this period, atmospheric CO2 concentrations in parts of South America typically may increase by 0.5 to 0.75 ppm at 970 mbar, the average pressure of the lowest model layer. These figures are above the probable uncertainty level, as model runs with biomass-burning sources estimated from independent studies using distinct data sets and techniques indicate. From May through September, when severe biomass burning occurs in South America, the effect of north African savanna fires over South America has become generally small at 970 mbar, but north of the equator it may be of the same magnitude or larger than the effect of South American fires. The CO2 concentration increase in the extreme northern and southern portions of South America, however, is mostly due to southern African fires, whose effect may be 2-3 times larger than the effect of South American fires at 970 mbar. Even in the central part of the continent, where local biomass-burning emissions are maximum, southern African fires contribute to at least 15% of the CO2 concentration increase at 970 mbar. At higher levels in the atmosphere, less CO2 emitted by north African savanna fires reaches South America, and at 100 mbar no significant amount of CO2 is transported across the Atlantic Ocean. The vertical

  7. North African savanna fires and atmospheric carbon dioxide

    NASA Technical Reports Server (NTRS)

    Iacobellis, Sam F.; Frouin, Robert; Razafimpanilo, Herisoa; Somerville, Richard C. J.; Piper, Stephen C.

    1994-01-01

    The effect of north African savanna fires on atmospheric CO2 is investigated using a tracer transport model. The model uses winds from operational numerical weather prediction analyses and provides CO2 concentrations as a function of space and time. After a spin-up period of several years, biomass-burning sources are added, and model experiments are run for an additional year, utilizing various estimates of CO2 sources. The various model experiments show that biomass burning in the north African savannas significantly affects CO2 concentrations in South America. The effect is more pronounced during the period from January through March, when biomass burning in South America is almost nonexistent. During this period, atmospheric CO2 concentrations in parts of South America typically may increase by 0.5 to 0.75 ppm at 970 mbar, the average pressure of the lowest model layer. These figures are above the probable uncertainty level, as model runs with biomass-burning sources estimated from independent studies using distinct data sets and techniques indicate. From May through September, when severe biomass burning occurs in South America, the effect of north African savanna fires over South America has become generally small at 970 mbar, but north of the equator it may be of the same magnitude or larger than the effect of South American fires. The CO2 concentration increase in the extreme northern and southern portions of South America, however, is mostly due to southern African fires, whose effect may be 2-3 times larger than the effect of South American fires at 970 mbar. Even in the central part of the continent, where local biomass-burning emissions are maximum, southern African fires contribute to at least 15% of the CO2 concentration increase at 970 mbar. At higher levels in the atmosphere, less CO2 emitted by north African savanna fires reaches South America, and at 100 mbar no significant amount of CO2 is transported across the Atlantic Ocean. The vertical

  8. Late Quaternary fluvial terrace development and changing landscape connectivity in the Great Karoo, South Africa.

    NASA Astrophysics Data Sy