Volume 11, Number 2
Summer 1999

New Report Shows Wilderness Habitat Essential To Grizzly Bear and Bull Trout Preservation
By Mike Bader, AWR Executive Director

I presented a research report at the Wilderness Science in a Time of Change conference in Missoula in late May. The new study describes the high value of wilderness habitat for grizzly bear and bull trout recovery.

Analysis of grizzly bear mortality data found that of all grizzly deaths from all causes, approximately twice as many grizzly bears in the Yellowstone and Northern Continental Divide Ecosystems died on non-wilderness lands as in wilderness. Approximately 64% of all mortalities occurred within 2 km of roads and 4 km of major developed areas. Wilderness is a "source" habitat for grizzly bears and bull trout, while the roaded landbase of non-wilderness lands are a "sink" habitat, meaning more bears die there than the local population can replace. Nearly 80% of the area inhabited by strong populations of bull trout is comprised of wilderness habitats. Wilderness habitat was defined as: designated wilderness areas; inventoried roadless areas; and roadless national park lands. For grizzly bears this definition was modified by buffering roads 2 km on either side, and major developments were buffered to a 4 km radius. The report's conclusion is that de-listing and resumption of hunting for grizzly bears could destabilize the Yellowstone and Northern Continental Divide Ecosystem (NCDE) populations, further threatening their status.

Core Habitat is Vulnerable
Moreover, the study found the density of mortalities has shifted from wilderness to non-wilderness lands following the end of legal hunting seasons for grizzly bears. While about twice as many grizzlies died on non-wilderness lands compared to wilderness in the Yellowstone area when legal hunting was allowed, the ratio increased to approximately 2.5 times after hunting was stopped. In the NCDE this shift was even more pronounced, with the ratio increasing from about 1.2 to approximately 4.5 times as many grizzlies dying on non-wilderness habitat compared to wilderness habitats after hunting seasons ended. De-listing of grizzly bears from the list of threatened and endangered species has been proposed and the states of Wyoming and Montana have indicated they wish to resume legal hunting for grizzly bears. Most legal hunting kills occurred in wilderness habitat. If hunting were resumed, it could shift the density of mortalities back into the core habitat. Taking bears from the core habitat could be similar to deficit spending: it robs from the "principle" rather than harvesting the "interest." This could "bankrupt" grizzly bear populations. Some have claimed hunting is compensatory mortality, removing unwary, problem bears from the ecosystems, and reducing the need for costly and management-intensive control actions. However, the report found that the mean annual mortalities decreased after hunting ended from 25.0 to 10.4 in the Greater Yellowstone Ecosystem and from 19.1 to 13.0 in the Northern Continental Divide Ecosystem in northwest Montana, indicating that many hunting mortalities are additive. Since most hunting kills occurred in remote wilderness backcountry areas, hunting targets wary bears, while human-habituated bears in non-wilderness frontcountry areas continue to face high mortality rates, particularly in poor food years like 1998, when 23 grizzly bears died in the NCDE.

Increase in Conflicts Likely
The study also found that the spatial distribution of grizzly bear mortalities is linked to the presence of roads, trails, and major developments. These "corridors of death" are a major limiting factor on grizzly populations. As more people move into grizzly bear country and human use of grizzly bear habitat increases, bear-human conflicts are likely to continue rising. Therefore, the value of the wilderness source habitat is becoming even more important to grizzly bear survival. Habitat continues to be altered or lost around the fringes of the population areas. Hunting in core wilderness source habitats would be at least partially additive, and increases the chances that overall mortality will rise and annual mortalities exceed the ability of the population to absorb these losses without negative population growth. While Alliance for the Wild Rockies is pro-hunting in general, we oppose hunting of grizzly bears in the lower 48 states on biological grounds. Grizzly bears have been diminished to less than 2% of their original numbers and habitat. Every extra mortality is a threat to these fragile populations.

Wilderness Fragmentation
The study also found that populations of 50 or more grizzly bears in the Northern Rockies occur only in association with large blocks of wilderness habitat. Wilderness habitat in the Northern Rockies may already be too small and fragmented to prevent excessive grizzly bear mortality, especially in poor food crop years, noting that mortality quotas for grizzly bears have been exceeded in the NCDE in 1992, 1995, 1997, and 1998 and were exceeded in the Yellowstone area in four of the last five years. "What grizzly bears really need is habitat security and wilderness habitat is the most secure for grizzly bears ... It's pretty clear that without wilderness, we will not have grizzly bears in the future," the report concludes. Wilderness habitat areas also contain the cleanest, coldest waters essential to bull trout populations.

Key recommendations from the report include:

• Wilderness habitat needs greater protection. Less than 50% of the wilderness habitat in the Northern Rockies has official legal protection and remains vulnerable to degradation. The Northern Rockies Ecosystem Protection Act is put forth as a plan that would do a lot for grizzly bear and bull trout habitat protection.
• More road closures are necessary to adequately protect grizzly bear populations and increase the "source" habitat area.
• Wilderness habitat is fragmented, and must be linked together with a system of linkage corridors.
• Greater hunter education effort is needed to reduce mistaken identity kills during black bear hunting seasons. Managers may wish to consider restricting black bear hunting seasons within occupied grizzly bear habitat, particularly during the spring and use of baits should be permanently prohibited.
• Much of the existing wilderness habitat is located at higher elevations. More wilderness habitat at lower elevations is needed to benefit both grizzly bears and bull trout.