Résultats de la recherche | Land Portal

Résultats de la recherche

Showing items 1 through 9 of 15.
  1. Library Resource
    Articles et Livres
    août, 2014
    France, Royaume-Uni, Kenya, États-Unis d'Amérique, Afrique orientale, Amérique septentrionale, Europe septentrionale, Europe occidentale

    Biodiversity continues to decline in the face of increasing anthropogenic pressures such as habitat destruction, exploitation, pollution and introduction of alien species. Existing global databases of species’ threat status or population time series are dominated by charismatic species. The collation of datasets with broad taxonomic and biogeographic extents, and that support computation of a range of biodiversity indicators, is necessary to enable better understanding of historical declines and to project – and avert – future declines.

  2. Library Resource
    Articles et Livres
    décembre, 2014
    Canada

    Flows from river basins in northwestern Canada have been rising in the last two decades as a result of climate warming. In the wetland‐dominated basins that characterise the southern margin of permafrost, permafrost thaw and disappearance, and resulting land‐cover change, is occurring at an unprecedented rate. The impact of this thaw on runoff generation in headwater basins is poorly understood.

  3. Library Resource
    Articles et Livres
    décembre, 2014
    États-Unis d'Amérique

    BACKGROUND: Recent evidence indicates that some populations of European corn borer (ECB), Ostrinia nubilalis (Hübner), have declined to historic lows owing to widespread adoption of Bt corn hybrids. To understand current ECB populations in Pennsylvania field corn, the authors assessed larval damage in Bt and non‐Bt corn hybrids at 29 sites over 3 years. The influence of Bt adoption rates, land cover types and moth activity on levels of ECB damage was also considered.

  4. Library Resource
    Articles et Livres
    décembre, 2014
    Canada

    The hydrology of boreal regions is strongly influenced by seasonal snow accumulation and melt. In this study, we compare simulations of snow water equivalent (SWE) and streamflow by using the hydrological model HYDROTEL with two contrasting approaches for snow modelling: a mixed degree‐day/energy balance model (small number of inputs, but several calibration parameters needed) and the thermodynamic model CROCUS (large number of inputs, but no calibration parameter needed).

  5. Library Resource
    Articles et Livres
    décembre, 2016
    États-Unis d'Amérique

    One challenge in the effort to conserve biodiversity is identifying where to prioritize resources for active land management. Cost–benefit analyses have been used successfully as a conservation tool to identify sites that provide the greatest conservation benefit per unit cost. Our goal was to apply cost–benefit analysis to the question of how to prioritize land management efforts, in our case the application of prescribed fire to natural landscapes in Wisconsin, USA.

  6. Library Resource
    Articles et Livres
    décembre, 2014
    Canada

    Mining disturbs large forested areas around the world, including boreal forests after oil sands mining in Canada. Industrial companies are expected to reclaim degraded land to ecosystems with equivalent land capability. This research showed the value of woody debris for reclamation of dramatically disturbed landscapes with a forest ecosystem end land use. Adding woody debris during reclamation can facilitate recovery of flora, soil nutrient cycling and water and nutrient holding capacity.

  7. Library Resource
    Articles et Livres
    décembre, 2016
    États-Unis d'Amérique, Amérique septentrionale

    Understanding how landscape, host, and pathogen traits contribute to disease exposure requires systematic evaluations of pathogens within and among host species and geographic regions. The relative importance of these attributes is critical for management of wildlife and mitigating domestic animal and human disease, particularly given rapid ecological changes, such as urbanization.

  8. Library Resource
    Articles et Livres
    décembre, 2015
    Canada

    The Abbotsford‐Sumas Aquifer is arguably the most studied case in Canada of groundwater nitrate contamination associated with agricultural production. Underlying some of the most productive agricultural land in Canada, this highly vulnerable trans‐boundary aquifer provides a unique case study on the opportunities and challenges of addressing water quality issues. A groundwater monitoring program initiated in the early 1990s has been important in tracking spatial and temporal variation in groundwater nitrate concentration.

  9. Library Resource
    Articles et Livres
    décembre, 2015
    États-Unis d'Amérique

    Stream water temperature (tₛ) is a critical water quality parameter for aquatic ecosystems. However, tₛrecords are sparse or nonexistent in many river systems. In this work, we present an empirical model to predict tₛat the site scale across the USA. The model, derived using data from 171 reference sites selected from the Geospatial Attributes of Gages for Evaluating Streamflow database, describes the linear relationship between monthly mean air temperature (tₐ) and tₛ.

  10. Library Resource
    Articles et Livres
    décembre, 2016
    États-Unis d'Amérique

    A complete, spatially explicit dataset illustrating the 21st century mining footprint for the conterminous United States does not exist. To address this need, we developed a semi‐automated procedure to map the country's mining footprint (30‐m pixel) and establish a baseline to monitor changes in mine extent over time. The process uses mine seed points derived from the U.S. Energy Information Administration (EIA), U.S.

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