Grizzlies in the Yellowstone Ecosystem
The Yellowstone ecosystem is comprised of 2.2 million acres in the Park and about 4 million acres of surrounding wilderness areas, and is home to the largest remaining grizzly bear population in the lower forty- eight states. Yellowstone grizzlies were given endangered species status in the mid seventies and management programs were put in place to reduce their interactions with humans, the main cause of bear mortality.
The actual number of bears in the Yellowstone population and the rate of increase of the population are a matter of fierce contention. The Fish and Wildlife Service is under political pressure to remove the grizzly bear from the endangered species list, and has said that the grizzly population has grown at 5 percent per year since the mid eighties. However, Craig Pease and David Mattson’s demographic analysis of the Yellowstone grizzly population found that its size has changed little from 1975 when the bear was listed, to 1995 when some managers were claiming successful recovery. We spoke with David about his twenty years of work on grizzly bears.