Griz mortality remained steady, but what's sustainable?

Recorded grizzly bear mortality in the Northern Continental Divide Ecosystem in 2016 was the same the year before, with 22 total bears killed, primarily by human means.

Removal by wildlife biologists due to human conflicts was the leading cause of death, at nine. One bear, a male, was removed as part of an augmentation program to move grizzly bears from the NCDE to the Cabinet-Yaak ecosystem.

Of the 22 deaths in 2016, 12 were females. Two were unknown sex. Two bears were poached and two were killed by property owners illegally. Three were hit by cars and two deaths were determined to be natural causes, one was accidentally poisoned and one was shot by a hunter who mistook it for a black bear.

In 2015, biologists removed four bears, four were poached, two were hit by vehicles, two were killed by people acting in self defense, one was killed by a hunter who mistook its identity and two were undetermined.

The NCDE is an 8 million acre swath of land along the Continental Divide from Canada south to Ovando. It includes all of Glacier National Park, The Bob Marshall Wilderness and the Rocky Mountain Front.

Despite having nearly 3 million visitors come to Glacier in 2016, it did not have a grizzly bear death, though a bear did bite a Park employee who was picking huckleberries in Many Glacier.

Overall, a new demographic study of the bear population by Montana Fish, Wildlife and Parks estimates that with a bear population of 1,000, the sustainable mortality threshold is about 53 independent bears and a little higher — 60 bears, if more of the bears taken are males.

An “independent bear” is one that is not a cub or a yearling, the study notes. The mortality rate includes all forms of death, including an estimate of unknown or natural mortality.

Grizzlies, once they’re adults, generally don’t die of natural causes until later in life, or if they don’t have a conflict with humans, studies have found.

The sustainable mortality is an important number if bears are delisted from the Endangered Species Act and a hunting season is enacted.

Since the bears were listed in 1979, they have essentially doubled their range, the study found, from 23,000 square kilometers to 53,000 square kilometers today.

While the population has been on the upswing, the report also cautions bear managers in the future, noting that “the consequence of error in population management is high, as grizzly bears reproduce slowly and reduced populations will require many years to recover.”

One potential caveat in setting a future hunting season, is whether or not to include the grizzlies living in Glacier National Park as part of the huntable population.

About 300 grizzlies live in the Park, some leave and enter, others spend their whole lives there. But Glacier doesn’t allow hunting, so whether the bears should be included as part of the overall huntable population hasn’t been determined yet, noted FWP biologist Cecily Costello, who co-authored the demographic report.

If Glacier bears are excluded from the huntable population, the overall sustainable mortality would drop to about 37 independent bears based on one scenario and about 42 independent bears based on a scenario with more male mortality.

Delisting bears is a long and politically-charged process. Last week, the U.S. Fish and Wildlife Service announced it was delaying delisting grizzly bears in the Greater Yellowstone Ecosystem. Many Native American Tribes, including teh Blackfeet Tribe east of Glacier Park oppose hunting grizzlies. Last summer, tribes held a ceremony in Glacier recognizing the grizzly and its importance to their culture.