Résultats de la recherche | Land Portal

Résultats de la recherche

Showing items 1 through 9 of 5.
  1. Library Resource
    Publication évaluée par des pairs
    mai, 2015
    Fédération de Russie, Groenland, Suède

    The upper treeline of Scots pine (Pinus sylvestris L.) is renowned as a sensitive indicator of climate change and variability. By use of megafossil tree remains, preserved exposed on the ground surface, treeline shift over the past millennium was investigated at multiple sites along the Scandes in northern Sweden. Difference in thermal level between the present and the Medieval period, about AD 1000-1200, is a central, although controversial, aspect concerning the detection and attribution of anthropogenic climate warming.

  2. Library Resource
    Publication évaluée par des pairs
    septembre, 2009
    États-Unis d'Amérique

    The effects of landscape context on habitat quality are receiving increased attention in conservation biology. The objective of this research is to demonstrate a landscape-level approach to mapping and evaluating the anthropogenic risks of grassland and forest habitat degradation by examining habitat context as defined by intensive anthropogenic land uses at multiple spatial scales.

  3. Library Resource
    Publication évaluée par des pairs
    octobre, 2012
    Europe, Amérique septentrionale

    Wild herbivorous mammals may damage treeline vegetation an cause soil erosion at a local scale. In many high
    mountain areas of Europe and North America, large numbers of red deer have become a threat to the maintenance
    of high-elevation forests and attempts to restore the climatic treeline. In northern Fennoscandia, overgrazing by
    reindeer in combination with mass outbreaks of the autumnal moth are influencing treeline dynamics. Moose are
    also increasingly involved damaging treeline forest. In the Alps, the re-introduction of ibex is causing local damage

  4. Library Resource
    Publication évaluée par des pairs
    octobre, 2012
    États-Unis d'Amérique

    Peninsula effects - decreasing richness with increasing distance along peninsula lobes - have been identified for
    many taxa on large peninsulas. Peninsula effects are caused by differences in colonization and extinction predicted
    by island biogeography or by environmental gradients along the peninsula. We compared species-area regressions
    for cove patches (i.e., mainland) to regressions for lobe patches (i.e., on peninsula tips) for wet meadow birds
    along a highly interdigitated shoreline (northern Lake Huron, USA). We conducted analysis both with and without

  5. Library Resource
    Publication évaluée par des pairs
    octobre, 2008
    États-Unis d'Amérique

    The Conservation Reserve Program (CRP) is a voluntary set-aside program in the United States designed to amelioratesoil erosion, control crop overproduction, enhance water quality, and provide wildlife habitat by replacing crops with other forms of land cover. Because CRP includes primarily grass habitats, it has great potential to benefitdeclining North American grassland bird populations. We looked at the change in national and state population trends of grassland birds and related changes to cover-specific CRP variables (previous research grouped all CRP practices).

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