How Many Habitats do Landscapes Contain?

The successful integration of theories of habitat selection into landscape ecology depends upon the proper identification of habitat. Habitats must be distinguished at appropriate spatial scales, and evidence must be provided that individuals recognize and respond to the habitat classification. We use evolutionary theories to document how density- dependent habitat selection and habitat variation can be applied to identify habitats in landscapes. We apply our protocol to small-mammal (Clethrionomys gapperi) populations across a series of repeated landscapes in the Hudson Bay Lowland of Ontario, Canada. We postulated initially that the landscapes were composed of two easily distinguishable habitats, but our protocol demonstrated three habitat types influencing density-dependent habitat selection by C. gapperi. The third habitat has profound implications for population regu- lation in the lowland and highlights the importance of proper habitat identification.