An intensive DNA study will help wildlife managers design better recovery strategies for the threatened bears.
To snag a grizzly bear, a mixture of decomposed fish guts and aged cattle blood works quite nicely, Kate Kendall has found. Kendall, a U.S. Geological Survey research ecologist, isn't interested in capturing entire animals, just snatches of hair for DNA studies. The gory concoction is applied on piles of forest debris, and barbed wire is stapled to surrounding trees. Tufts of fur catch when the enormous omnivores—males stand seven feet tall and top out at 600 pounds—investigate the alluring scent.
Kendall will be using this non-invasive sampling approach in northwestern Montana and northern Idaho this summer as part of a three-year study that began last year. The goal is to gain a more precise estimate of the grizzly population in the 1.7-million-acre Cabinet-Yaak ecosystem, one of six federally designated recovery zones for grizzlies, listed as threatened since 1975.
During the past three decades biologists have radio-collared a handful of bears in the Cabinet-Yaak ecosystem, and the U.S. Fish and Wildlife Service estimates that 40-45 grizzlies live in its recovery zone. Using a DNA-based approach should paint a clearer picture, not only by giving a more accurate count but also by providing the gender breakdown and genetic diversity within the population.
two Grizzlies in the Winter woods in the Yaak
Kendall spearheaded a similar study in Montana's Northern Continental Divide ecosystem, collecting some 34,000 samples from 765 grizzlies—a number that turned out to be more than twice the previous population estimate.
"Grizzly bear recovery in the Cabinet-Yaak ecosystem is one of our highest priorities," says Paul Bradford, chair of the Selkirk/Cabinet-Yaak subcommittee of the Interagency Grizzly Bear Committee and supervisor of Montana's Kootenai National Forest. Other recovery zones, like the Northern Continental Divide and Yellowstone, have benefited from intensive, multimillion-dollar studies. "I think [this] DNA study will provide needed additional data that help us better understand the existing situation of the population, and help us design better recovery strategies," he says.
road closures reduce Griz mortality caused by humans
It's not just wildlife managers who are anxious to get a solid population number—local communities have a vested interest, too. "It's a huge management and economic question," says Kendall. "That's why it's so important to find out with certainty what the population status is right now, to have a good measure of trend, and to figure out if we're managing bears as well as we can to promote recovery."
Because of the bear's threatened status, some U.S. Forest Service roads have been closed to protect grizzly habitat, and logging and mining operations limited. In fact, many of the corporations, communities, and individuals affected by the restrictions are pitching in to fund the $1.7 million study, along with federal and state agencies.
The Cabinet-Yaak ecoregion
"We think the numbers are higher than currently estimated—we're hearing from our friends and neighbors that they're running into grizzly bears more than they ever have," says Lincoln County commissioner Tony Berget. "We'd like to know how many are really out there so we can move forward and set a plan in motion to get these grizzlies recovered.
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Besides setting up 395 baited hair traps in 790 different locations, Kendall's team is putting barbed wire on natural bear rubs—trees and structures that the animals regularly shimmy up against, giving their backs and sides a good scratch.
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Cabinet-Yaak Grizzly Bear Project
Principal Investigator
Katherine C. Kendall, USGS Glacier Field Station, Glacier National Park, West Glacier, MT 59936-0128 kkendall@usgs.govObjectives
- Estimate of Population Size: Use sign surveys and systematic hair snag stations to obtain an estimate of the number of grizzly bears in the Cabinet-Yaak Ecosystem (CYE) in northwest Montana and northeast Idaho.
- Genetic Library: Develop a genetic database for grizzly bears in the CYE to assess genetic diversity and degree of relatedness of the CYE grizzly bear population.
Background
Grizzly bears (Ursus arctos horribilis) once roamed most of the North American continent. Habitat destruction and direct conflicts with humans have reduced their range by 99% in the lower 48 states (right, click on map for larger version). In 1975 grizzly bears were listed as threatened under the Endangered Species Act. The Cabinet-Yaak Ecosystem (CYE) in northwest Montana and northeast Idaho is one of six recovery zones defined in the Grizzly Bear Recovery Plan (U.S. Fish and Wildlife Service 1993).The CYE is the fourth largest in area and contiguous to a small Canadian population. Estimates place the total number of grizzlies that remain south of the Canadian border at fewer than 1100. It is thought there are between 30-40 animals within the 2,600 square-mile Cabinet-Yaak recovery zone. For more information about grizzly bear recovery, visit the U.S. F&WS Grizzly Bear Recovery Office webpage.
Related Materials
- Cabinet-Yaak Grizzly Bear Project Information Sheet (pdf format): A study to estimate the grizzly bear population size in the Cabinet-Yaak Ecosystem
Related Projects
- Northern Divide Bear Project (2003-2008): project website
- Greater Glacier Bear DNA Project (1997-2002): project website
- Use of Remote Camera Systems: Remote video and still cameras were used to: investigate how grizzly bears, black bears, and other wildlife species respond to baited, barbed wire hair traps; bear use of naturally-occurring bear rubs, bear marking behavior, and effects of putting barbed wire on bear rubs to facilitate hair collection; how hair traps may be modified to improve detection probabilities. Use of remote camera systems to investigate efficiency of DNA-based sampling methods
Keywords
grizzly bear, black bear, DNA finger printing, mark-recapture, wildlife, population, landscape scale, non-invasive sampling, conservation genetics, hair, microsatellites, polymerase chain reaction, Ursus arctos, Ursus americanus, hair snag, sign survey, genetics, Kootenai National Forest, Cabinet-Yaak Ecosystem, Montana, Idaho
Geographic Distribution
Cabinet-Yaak Ecosystem, Northwest Montana
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