History of the IGBST

Science Center Objects

A heated debate began in the 1960s and 1970s and grew to a national scope concerning the grizzly bears in the GYE. For decades, grizzly bears were allowed to rummage through garbage dumps searching for food. As early as the 1940s, some researchers suggested closing the open-pit dumps within Yellowstone National Park. In 1963, the Advisory Board on Wildlife Management in the National Parks released the “Leopold Report” which recommended that natural ecosystems should be recreated, including predator/prey relationships.

Grizzly bear standing on hind legs while garbage truck is unloading garbage at the Trout Creek dump in Yellowstone National Park
Grizzly bear standing on hind legs while garbage truck is unloading garbage at the Trout Creek dump in Yellowstone National Park; Photographer unknown; 1970 
(Public domain.)

In the early 1900s grizzly bears were allowed, and often encouraged, to feed on garbage in Yellowstone National Park.  By 1967, Yellowstone National Park’s Superintendent Anderson began to implement recommendations of the 1963 Leopold Report, a document written by the Advisory Board on Wildlife Management in the National Parks that recommended that natural ecosystems should be recreated, including predator/prey relationships. The Park began closing the open-pit dumps to wean bears off garbage. Some researchers recommended gradually phasing out the dumps, but Park staff chose to close Park dumps abruptly to prevent behaviors of reliance on human foods being passed on to another generation of bears. This caused controversy because conflicts with humans increased substantially as dumps were closed, causing many grizzly bear mortalities. Between 1967 and 1972, a minimum of 229 Yellowstone ecosystem grizzlies died. Higher mortality was anticipated and the decision was rationalized based on the assumption that there were enough backcountry bears that did not use dumps to sustain the mortality.

In 1973, as a direct result of this controversy and lack of information regarding the status of the Yellowstone grizzly bear population, the Department of Interior formed a group of scientists known as the Interagency Grizzly Bear Study Team or IGBST.   The high mortality that followed the dump closures and concerns for the population’s future were also factors that contributed to the decision to list grizzly bears in the lower 48 states as Threatened under the Endangered Species Act in 1975.  Early research by the IGBST indicated that following listing, the population continued to decline into the 1980s. This information was the foundation and impetus for the formation of the Interagency Grizzly Bear Committee (IGBC) in 1983. The IGBC, represented by administrators from federal and state agencies, implemented regulations on federal lands designed to reduce human-caused grizzly bear mortality.   These included food-storage orders on federal lands designed to reduce availability of human foods to bears, and reduction of sheep grazing allotments within the designated grizzly bear recovery zone, as well as actions by Yellowstone National Park that increased the abundance of natural foods, such as cessation of culling elk and bison herds. These management policies likely halted the population’s decline.  Since the mid-1980s grizzly bear numbers have increased and today the population once again occupies historical range approximately 7 times the size of Yellowstone National Park.