Spatial scaling in northern landscapes : habitat selection by small mammals

Abstract

I examined a series of simple and repeated northern landscapes in the Hudson Bay Lowland of Ontario to document regional and local patterns of population abundance of red-backed voles {Clethrionomys gapperi). I tested whether a spatially-explicit ecological process, density-dependent habitat selection, could account for population regulation of voles across a range of spatial scales. Over a large regional scale, multiple regression analysis indicated that population density of voles was primarily predicted by location of sampling and measures of microhabitat. Regional abundance patterns, therefore, appear to be independent of nonadditive landscape effects and probably result from large-scale biogeographic influences or differences in average habitat quality between sites. At a local scale, my analysis identified density-dependent habitat selection as a universal process structuring abundance patterns, regardless of regional differences in population density. Habitat selection, at the dispersal and perhaps microhabitat scales, thereby provides a feasible mechanism linking landscape structure directly to population regulation.