Intraspecific variation in home range overlap with habitat quality: A comparison among brown bear populations

We developed a conceptual model of spatial organization in vertebrates base d upon changes in home range overlap with habitat quality. We tested the mo del using estimates of annual home ranges of adult females and densities fo r 30 populations of brown bears (Ursus arctos) in North America. We used se asonality as a surrogate of habitat quality, measured as the coefficient of variation among monthly actual evapotranspiration values for areas in whic h study populations were located. We calculated home range overlap for each population as the product of the average home range size for adult females and the estimated population density of adult females. Home range size var ied positively with seasonality; however, home range overlap varied with se asonality in a nonlinear manner. Areas of low and high seasonality supporte d brown bears with considerable home range overlap, but areas of moderate s easonality supported brown bears with low home range overlap. These results are consistent with behavioural theory predicting a nonlinear relationship between food availability and territoriality.