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Showing items 1 through 9 of 109.
  1. Library Resource
    Journal Articles & Books
    December, 2012

    1. Arctic vegetation tends to be spatially heterogeneous and can have large areas of mixed ‘transition zone’ vegetation between stands dominated by a single or few species. If plant photosynthesis and growth within these transition zones differs significantly from main vegetation stands, and if transition zones are not considered when extrapolating stand‐level findings to larger scales in space, then transition zones will provide considerable error to landscape‐level estimates of gross primary productivity (GPP).

  2. Library Resource
    Journal Articles & Books
    December, 2014
    United States of America, Northern America

    AIM: The geographical expansion of white‐winged doves (Zenaida asiatica) in North America has attracted the attention of biologists and sportsmen because of their recreational and aesthetic value; however, data on factors driving the spatial spread of this species are lacking. We examined spatial and temporal patterns of range expansion for white‐winged doves along the northern edge of their geographical range from 1979 to 2007 and used a dynamic occupancy model to estimate when and where doves would be found along an expansion gradient. LOCATION: Southern half of the USA.

  3. Library Resource
    Journal Articles & Books
    December, 2015
    Finland

    Quantifying landscape‐scale methane (CH₄) fluxes from boreal and arctic regions, and determining how they are controlled, is critical for predicting the magnitude of any CH₄ emission feedback to climate change. Furthermore, there remains uncertainty regarding the relative importance of small areas of strong methanogenic activity, vs. larger areas with net CH₄ uptake, in controlling landscape‐level fluxes.

  4. Library Resource
    Journal Articles & Books
    December, 2002
    Sweden, Italy, Europe

    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.

  5. Library Resource
    Journal Articles & Books
    December, 2014
    Iran

    Nabis pseudoferus Remane and N. palifer Seidenstucker are predators that feed on a wide range of insect pests. To reveal their current potential habitats, the effects of climate change and their future distribution in various areas of Iran we used maximum entropy modeling (Maxent). To produce the models, samples were collected from 218 areas of Iran resulting in discovering 271 points where the nabids were found. The accuracy and performance of distribution models were also evaluated by the area under receiver operating characteristic curve and jack‐knife analysis.

  6. Library Resource
    Journal Articles & Books
    December, 2015

    Land‐cover change and ecosystem degradation may lead to biotic homogenization, yet our understanding of this phenomenon over large spatial scales and different biotic groups remains weak. We used a multi‐taxa dataset from 335 sites and 36 heterogeneous landscapes in the Brazilian Amazon to examine the potential for landscape‐scale processes to modulate the cumulative effects of local disturbances.

  7. Library Resource
    Journal Articles & Books
    December, 2014
    Georgia

    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.

  8. Library Resource
    Journal Articles & Books
    December, 2014
    Germany

    The National Forest Soil Inventory (NFSI) provides the Greenhouse Gas Reporting in Germany with a quantitative assessment of organic carbon (C) stocks and changes in forest soils. Carbon stocks of the organic layer and the mineral topsoil (30� cm) were estimated on the basis of ca. 1.800 plots sampled from 1987 to 1992 and resampled from 2006 to 2008 on a nationwide grid of 8� � 8� km. Organic layer C stock estimates were attributed to surveyed forest stands and CORINE land cover data.

  9. Library Resource
    Journal Articles & Books
    December, 2016

    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.

  10. Library Resource
    Journal Articles & Books
    December, 2016

    Increasing community dissimilarity across geographic distance has been described for a wide variety of organisms and understanding its underlying causes is key to understanding mechanisms driving patterns of biodiversity. Both niche‐based and neutral processes may produce a distance decay relationship; however, disentangling their relative influence requires simultaneous examination of multiple potential drivers.

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