Montana

Brown bear populations in the lower to 48 states have been greatly reduced in numbers and their habitat has been fragmented by human development.

There are three major large 'islands' of bear habitat in the United States and adjacent Canada. These have been designated as the Northern Continental Divide Ecosystem (NCDE on map), Bitterroot (or Salmon-Selway) Ecosystem (SSE on map), and Yellowstone Grizzly Bear Ecosystem (or Greater Yellowstone Ecosystem; GYE on map) Recovery Zones by the U.S. Fish and Wildlife Service (USFWS 1993).

The cores of these areas are protected as National Parks (in both the U.S. and Canada) and Wilderness Areas. Additional lands around these cores are designated as grizzly bear recovery areas where maintaining viable grizzly bear populations is a management priority. Surrounding the recovery zones are some National Forest lands. Much of the National Forests are at present undeveloped. Some areas contain grizzly bear habitat and may support a few bears, other areas are only occasionally visited by grizzly bears.

Smaller islands of habitat exist, largely in Canada but extending over the U.S. border in the Cabinet Yaak Ecosystem (CYE), and Selkirk Mountains Ecosystem (SE).

These areas of habitat have been designated as Recovery Zones by the U.S. Fish and Wildlife Service. They have been determined to be sufficient to support a minimum brown bear population size recovery goal) deemed large enough to be self sustaining (USFWS 1993).

Between the three large 'islands' there are small 'stepping stones' of habitat that could possibly serve as corridors for movement.

Brown bear numbers are not known with certainty even in the Lower 48 States; different agencies often have different estimates. These estimates vary for the NCDE from 549 to 813 brown bears estimated by the Montana Department of Fish, Wildlife, and Parks (a density of about 22.1 bears per 1000 square kilometers) [Dood et. al. 1986] to a minimum of 306 bears (87 adult females) estimated by the U.S. Fish and Wildlife Service USFWS (1993) with a recovery goal of 391 bears.

The northernmost portion of the Greater Yellowstone Ecosystem (including the Yellowstone Grizzly Bear Recovery Zone) extends into Montana. Approximately 25-30 grizzly bears are estimated in the Gallatin National Forest. In the GYE at least 236 bears (67 adult females) are estimated for with a recovery target of 15 females with cubs per year; a density of about 11.2 bears per 1000 square kilometers (USFWS 1993). In 1994 there were 11 known mortalities in the Yellowstone Ecosystem (including 2 adult females and one subadult female). In 1995 there were 18 known mortalities (including 3 adult females, 3 subadult females, and one female cub).

In a recent publication, Eberhard and Knight (J. Wildl. Manage. 60(2):416-421) derive a variety of population estimates for the YGBE: A population review committee in 1994 estimated a minimum total population of 245 grizzly bears. An estimate based on ages of all bears handled and identified gives an absolute minimum of 133 bears. An estimate using females in a Petersen Index with Chapman's bias corrected equation suggests a total population of 390 bears. An estimate from distinct family records yields 339 bears (for which the 90 percent confidence interval is 280 to 610 bears).

Analysis of genetic samples of 667 grizzlies, 72 of which were from Yellowstone, demonstrated a significantly lower H (55%) for Yellowstone grizzlies compared to a high of 78% in the Kluane sample (n=50) and a low of 26% in the Kodiak sample. Estimates of Ne ("genetic effective size" ) for the total Greater Yellowstone Ecosystem population are only 15-54 effective grizzly bears however (Paetkau D., L. Waits, L. Craighead, E. Vyse, R. Ward, and C. Strobeck. 1997. Dramatic variation in genetic diversity in brown bears across North America: implications for conservation. In Review, Cons. Bio.)

Eberhard and Knight's current estimates show a 2 to 5 percent increase. Other researchers (Mattson and Pease, 10th IBA proceedings, in press) question these findings.

Only 15 to 20 bears (density of about 2.2 bears per 1000 square kilometers) are estimated as a minimum population for the Cabinet Yaak (within the U.S.) with a recovery goal of 106 for the area on both sides of the border (USFWS 1993). Grizzly bear numbers on the Canadian side are also low.

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