Den selection by grizzly bears on a managed landscape

Den selection by grizzly bears on a managed landscape

Mama Grizzly and the polar bears.

A recent paper on the matrilineal population history of two sister species, Ursus maritimus (polar bears) and Ursus arctos (brown bears), based on mtDNA sequence analysis, reveals a comparatively recent introgression. The authors propose that it represents a signature of environ mental stress in marginal habitats [1]. In a nutshell, it means that all modern polar bears probably belong to a mate...

Despotism and Risk of Infanticide Influence Grizzly Bear Den-Site Selection

Given documented social dominance and intraspecific predation in bear populations, the ideal despotic distribution model and sex hypothesis of sexual segregation predict adult female grizzly bears (Ursus arctos) will avoid areas occupied by adult males to reduce risk of infanticide. Under ideal despotic distribution, juveniles should similarly avoid adult males to reduce predation risk. Den-sit...

Trophic cascades from wolves to grizzly bears in Yellowstone.

We explored multiple linkages among grey wolves (Canis lupus), elk (Cervus elaphus), berry-producing shrubs and grizzly bears (Ursus arctos) in Yellowstone National Park. We hypothesized competition between elk and grizzly bears whereby, in the absence of wolves, increases in elk numbers would increase browsing on berry-producing shrubs and decrease fruit availability to grizzly bears. After wo...

Trophic cascades from wolves to grizzly bears or changing abundance of bears and alternate foods?

This is a Forum article commenting on: Ripple, W. J., Beschta, R. L., Fortin, J. K., & Robbins, C. T. (2014) Trophic cascades from wolves to grizzly bears in Yellowstone. Journal of Animal Ecology, 83, 223-233. Comparisons Ripple et al. (2014) used to demonstrate increased fruit availability and consumption by grizzly bears post-wolf reintroduction are flawed and tenuous at best. Importantly, a...