DNA study tallies 545 grizzlies

The Daily Inter Lake

A massive DNA-based population study has identified 545 individual grizzly bears roaming the 7.8 million-acre Northern Continental Divide Ecosystem when the study was conducted in summer 2004.

That reflects the minimum number of bears in the study area that summer, based on genetic analysis of 33,000 hair samples that were collected.

Information about the individual bears will be applied to a series of statistical models to generate an unprecedented population estimate that will be larger than the minimum count of 545.

That estimate is scheduled for a peer review and publication sometime next summer, said Jeff Stetz, a wildlife biologist working on the project with U.S. Geological Survey researcher Kate Kendall.

Stetz on Wednesday briefed a committee of state, federal and tribal land and wildlife managers in Kalispell on the latest news about the Northern Divide Grizzly Bear Research Project.

Stetz told the Northern Continental Divide Ecosystem Subcommittee that the integrity of the research has proven to be extremely high, judging from results of "blind" samples correctly sorted out by the Canadian genetics laboratory that has processed the hair samples over the last couple of years.

The project's protocol for processing samples and evaluating data also passed the muster of a highly respected French researcher, Stetz said.

The project methods are being taken up for similar research around the world, he added.

"The project represents the state of the art in this type of work," Stetz said.

During summer 2004, 210 people went to work across the massive study area, collecting samples from scent-baited sites surrounded by barbed wire that snagged hair from bears that entered the sites. Hair samples also were collected from trees, telephone poles and other "rub sites" where bears routinely stopped to scratch their backs.

The analysis of the hair samples involved sorting black bears from grizzly bears.

Of the 545 individual grizzlies that were identified, 307 were female and 238 were male.

Largely because the field work produced more usable samples than originally expected, and because samples were collected using two methods, the modeled population estimate will have a higher level of statistical confidence, Stetz said.

"I think we are going to exceed what we set out to do," he said.

But the project will produce only a "snapshot in time" picture of the bear population. Bears have died and been born since then.

To account for population trends, Montana Fish, Wildlife and Parks has been leading a companion study across the same study area that involves monitoring female grizzly bears fitted with radio or satellite positioning collars.

That work, led by state research biologist Rick Mace, got under way in 2004.

Mace told the committee that the goal is to have at least 25 female bears fitted with collars every year through 2009, when the study is expected to produce a statistically reliable indication of whether the bear population is increasing or declining.

The DNA study has revealed that there is a higher density of grizzly bears in the northern end of the ecosystem - basically in and around Glacier National Park - than there is at the southern end in the Bob Marshall Wilderness Complex.

The trend study has been aimed at trying to catch and collar bears in a fashion that matches that distribution, Mace said.

Since the study started in 2004, 88 research bears have been captured, but not all have been fitted with collars, some collars have since dropped off and some bears have died, Mace said. This year's capture efforts were successful, maintaining 26 females with radio collars, Mace said.

The population estimate, combined with results from the trend study, are likely to have a profound influence on many aspects of grizzly bear management.

The studies could change habitat management, and they likely will play a part in any proposals to change the status of grizzlies as a "threatened" population under the Endangered Species Act.

Reporter Jim Mann may be reached at 758-4407 or by e-mail at jmann@dailyinterlake.com.