THE BEAR NECESSITIES: ECOLOGICAL EFFECTS OF THE WORLD'S LARGEST TERRESTRIAL OMNIVORE, URSUS ARCTOS.
Sean M. Denny; Bren School, University of California, Santa Barbara; Bren Hall, 2400 University of California, Santa Barbara, Santa Barbara, CA, 93117; (858) 847-8647; smdenny@bren.ucsb.edu; Molly Hardesty-Moore, Alexis M. Mychajliw, Ian M. McCullough, Scott D. Cooper, William J. Ripple, Thomas M. Newsome, Peter S. Alagona
Large mammals have declined dramatically in the last 500 years, mirroring a larger trend in anthropogenic megafaunal loss that extends back to the late Pleistocene. Concurrently, there has been a diminishment in the ecosystem roles played by large mammals, with consequences for ecosystem function, integrity, and resilience. In response, conservationists are working to stem these declines and facilitate large mammal recovery, with some success in North America and Europe. A delineation of the ecosystem impacts of large mammals is needed to predict and plan for repercussions of such extinctions and recoveries. The brown bear (Ursus arctos), the world's largest terrestrial omnivore, illustrates the ecological consequences of both large mammal loss and recovery. During the last two centuries, brown bear ranges have contracted across three continents, but specific North American and European populations have recovered. We review the ecological effects of brown bears, both past and present, direct and indirect, to illuminate the broader ecological consequences of changing densities and distributions of this iconic omnivore. We also discuss how human activities and climate change are altering brown bear ecology, and identify research priorities in the context of rapid, global change.
The Anthropocene: Decline & Extinction II   Student Paper