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Mostrando ítems 1 a 9 de 64.
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Wetlands are important providers of ecosystem services and key regulators of climate change. They positively contribute to global warming through their greenhouse gas emissions, and negatively through the accumulation of organic material in histosols, particularly in peatlands. Our understanding of wetlands’ services is currently constrained by limited knowledge on their distribution, extent, volume, interannual flood variability and disturbance levels.
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Offsets (also known as mitigation banks, compensatory habitat, set-asides) is a policy instrument recently introduced in several States in Australia to permit some land clearing while striving for no net loss in the extent and condition of native vegetation overall. Offsetting is criticized with respect to the amount of gain required to compensate for losses from clearing, the equivalence of losses and gains, the time lag between losses and gains and a poor record of compliance.
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Estimates of the percent of Earth's land surface that has either been transformed or degraded by human activity range between 39 and 50 percent, with agriculture accounting for the vast majority of these changes. Although much of the focus of research on land use and cover change in the tropics has been on deforestation, ongoing socioeconomic changes both locally and globally have made land transitions in the tropics extremely fluid. In addition, feedbacks between land cover change and human behavior constrain the extent and trajectories of land transitions.
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Projections of the response of crop yield to climate change at different spatial scales are known to vary. However, understanding of the causes of systematic differences across scale is limited. Here, we hypothesize that heterogeneous cropping intensity is one source of scale dependency. Analysis of observed global data and regional crop modelling demonstrate that areas of high vs. low cropping intensity can have systematically different yields, in both observations and simulations.
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Organic carbon (OC) sequestration in degraded semi‐arid environments by improved soil management is assumed to contribute substantially to climate change mitigation. However, information about the soil organic carbon (SOC) sequestration potential in steppe soils and their current saturation status remains unknown. In this study, we estimated the OC storage capacity of semi‐arid grassland soils on the basis of remote, natural steppe fragments in northern China. Based on the maximum OC saturation of silt and clay particles
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Europe is characterized not only by large geomorphological variability but also by a long history of land use. This resulted in a highly variegated landscape. Based on the IGBP‐transect initiative, a north south transect was established across Europe ranging from north Sweden to central Italy in order to study effects of global change. Mainly process oriented studies were established on plots along the transect, and these were used to establish functional relationships as basis for landscape integration.
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AIM: To disentangle whether long‐range periphery‐to‐core gradient of forest understorey plants could be attributed to past forest landscape and/or to current environmental filtering processes.
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This study assesses and characterizes the vulnerability of unregulated groundwater systems to microbial contamination in 18 counties in the state of Georgia using a contamination risk screening strategy based on watershed characteristics and elements of the Safe Drinking Water Act's Wellhead Protection program. Environmental data sources analyzed include septic systems, elevation, land use and land cover data, soil, vegetation coverage, demographics, and livestock.
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Artículos de revistas y libros
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Artículos de revistas y libros
Although agriculture is amongst the world's most widespread land uses, studies of its effects on stream ecosystems are often limited in spatial extent. National monitoring data could extend spatial coverage and increase statistical power, but present analytical challenges where covarying environmental variables confound relationships of interest. Propensity modelling is used widely outside ecology to control for confounding variables in observational data.
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