Résultats de la recherche | Land Portal

Résultats de la recherche

Showing items 1 through 9 of 4.
  1. Library Resource
    Articles et Livres
    décembre, 2014
    Canada

    Arctic ecosystems at the forest-tundra ecotone are particularly sensitive to climate-driven vegetation changes. Many recent studies have observed shifts in vegetation cover, particularly an increase in shrub growth. Here, vegetation changes were assessed at the local scale near Umiujaq, northern Quebec (Canada, 56.55°N, 76.55°W) using colour aerial photographs (1994 and 2010). By applying semi-automated image classification methods and change-detection analysis, we were able to detect and map the dominant vegetation cover changes.

  2. Library Resource
    Articles et Livres
    décembre, 2012
    Canada

    Invasive species are especially problematic when introduced into ecosystems with native congeners. The extent to which niches overlap in space determines whether the introduced species threatens the native one or the native species can escape competition or the effect of control. We compared the spatial distribution in relation to landscape and land-use/ land-cover variables of introduced and native Phragmites australis (common reed) in a landscape of protected freshwater wetlands in Quebec, Canada. Results showed that the wetlands still serve as refuges for native P. australis.

  3. Library Resource
    Articles et Livres
    décembre, 2009
    Canada

    Forest harvesting is a major cause of habitat alteration negatively affecting forest-dwelling caribou (Rangifer tarandus caribou) in the boreal forest. In order to identify female caribou habitat requirements, we conducted a fine-scale habitat selection analysis in a managed forest of eastern Canada. Five land-cover types used by 8 female caribou during 2 periods (winter and snow-free) were considered to characterize structural attributes, ground cover, and lichen abundance at 320 GPS locations and at 200 random points within home ranges.

  4. Library Resource
    Articles et Livres
    décembre, 2009
    États-Unis d'Amérique

    The extent to which woody vegetation exhibits more expansive community structures and different relationships with environmental variables than herbaceous plants is poorly understood in savannas and barrens worldwide, especially those with shallow soils. We explored this question in oak barrens, which are savanna habitats characterized by shallow soils, in southern Ohio, USA. Groundcover plant aerial cover and environmental data were collected using 75 randomly located 1-m2 quadrats in 3 barrens.

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