Influence de l'échelle spatiale sur les relations oiseaux-habitat

Authors: Renaud, Christine
Advisor: Desrochers, André
Abstract: Songbird presence is often associated with the area of habitat in the surrounding landscape. However, the extent of landscape for which habitat area is assessed is generally unknown. Studies have already demonstrated that some species are associated with the amount of habitat at the regional scale and that for certain species, measures of area-sensitivity vary depending on the spatial scale used. My goal was to demonstrate the influence of spatial scale on apparent area-sensitivity of forest songbirds. I tested the response of forest songbirds to habitat area measured inside nine radii from 100 m to 24 km, based on Ontario’s Forest Bird Monitoring Program, a long-term project initiated in 1987 by the Canadian Wildlife Service. Songbird occurrence was obtained from point counts distributed across southern and northwestern Ontario. Area of coniferous, deciduous and mixed forest was derived from landsat-TM satellite imagery. I used species-specific measures of habitat area to account for differences in preferred forest stand types among species. Forty-nine of the 52 species studied were area-sensitive for at least one radius. For most species, area-sensitivity varied depending on the extent of landscape considered. The radius at which area-sensitivity was strongest also varied greatly among species, making generalizations across species difficult. As a result, interspecific comparisons of area-sensitivity were strongly dependent on the choice of spatial extent. This study shows that the amount of habitat should be measured not only at the local and landscape scale, but also at the regional scale before attempting to draw conclusions on the association between a species’ presence and the area of habitat.
Document Type: Mémoire de maîtrise
Issue Date: 2005
Open Access Date: 11 April 2018
Grantor: Université Laval
Collection:Thèses et mémoires

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