Skiers, snowmobilers and hikers traveling in the Sawtooth National Recreation Area this winter may never spot a wolverine, but that doesn't mean they aren't disturbing the animals.
Backcountry recreationists in the mountains through late February may interrupt female wolverines' search for den sites in which to give birth. As wolverines have been proposed for protection under the Endangered Species Act, any disturbance of these animals naturally comes under scrutiny.
To that end, the U.S. Forest Service hopes to enlist the help of local backcountry skiers and snowmobilers in the Sawtooth National Recreation Area this winter in a study to correlate their movements with that of denning wolverines.
The South Central Idaho Resource Advisory Committee has approved $40,000 over the next two years to partially fund the study.
The committee doles out federal funds to projects in Blaine, Camas, Cassia and Twin Falls counties. The money comes from the federal Secure Rural Schools and Community Self-Determination Act of 2008. The law compensates counties for reduced tax revenue because of federal land within their boundaries.
The study is awaiting additional funding from the U.S. Forest Service. SNRA wildlife biologist Robin Garwood said she is "hopeful" it will come through.
The study began in the Payette National Forest last year with the tracking of three female wolverines, and could expand into the Sawtooth National Forest as early as this fall.
Kim Heinmeyer, project co-leader for the Idaho Wolverine Project, said her staff trapped six wolverines in the Payette National Forest last season, three of which were denning females. Recreationists were asked to wear GPS monitors to track their movements and locations. This data was compared with the wolverine data to see if the female wolverines had moved their den sites after humans had been nearby.
Garwood said the purpose of expanding the study into the SNRA is to gain a more reliable sample size. She said that though both she and Heinmeyer are unsure of the sample size required, she hopes to capture at least three females in the SNRA during each year of the study.
"More is always better," Heinmeyer said, as larger sample sizes lead to more accurate data.
A study of wolverines is also expected to start in the Boise National Forest this fall.
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Garwood said the results of this larger study are expected to be reliable enough to help the SNRA make "better travel management decisions." Heinmeyer said that with improved equipment, skiers and snowmobilers are traveling to higher elevations and more remote locations where wolverines are normally found.
Heinmeyer said there is evidence that female wolverines are sensitive to disturbance, but anecdotal evidence as to whether recreationists constitute a serious disturbance is contradictory. A scientific study would provide more data, she said.
Wolverines mate from June to August, but females don't begin to seek out natal dens until late February or early March. Though the animals are normally wide-ranging, Garwood said den-seeking females tend to stay in a smaller area and are therefore easy to spot.
Ideally, Garwood said, she hopes to trap and collar the wolverines in January 2011. She said some log live traps will need to be built this fall, but the SNRA has traps left from other studies that could be retrofitted.
Researchers in the Payette National Forest collared some males last winter, but Garwood said the SNRA will put GPS and radio collars on females only.
Though wolverines have proven to be adept collar-slippers during past studies, Heinmeyer said new technology has allowed radio collars to be lighter and less bothersome to the animal. Up-to-date radio collars also record animals' locations every 20 minutes.
"We needed that kind of accuracy," Heinmeyer said.
Still, two of the six animals captured in 2010 slipped their collars. Both were recaptured and re-collared with minimal data loss.
Garwood and her staff will begin distributing GPS armbands on trailheads throughout the SNRA in January. Garwood wasn't certain which trailheads they would use, as this study is still mostly in the planning stages, but recreationists in the Galena, Smiley Creek and Stanley areas will most likely be able to participate.
Heinmeyer said her staff saw remarkable public participation in the Payette National Forest, with 90 percent of recreationists returning their GPS units and the accompanying data. Some local merchants provided incentives for people to return the devices, offering discounts or free merchandise in exchange.
Heinmeyer said she was surprised by the amount of data collected and the public participation in the study.
"We were successful beyond our expectations, for sure," she said, adding that she has high hopes for this year as well.
Conservationists have petitioned the U.S. Fish and Wildlife Service to list the wolverine under the Endangered Species Act. They claim that as few as 550 wolverines could still survive in the lower 48 states, though Garwood said that number is difficult to determine.
Garwood said that this study will also receive some funding from the U.S. Fish and Wildlife Service.
"They're as interested in [this study] as we are," she said, adding that the locally based study is part of a larger effort to preserve wolverines.
Katherine Wutz: kwutz@mtexpress.com
Potential Timeline
The study of wolverine response to winter recreation occurs over two years. Here's what the SNRA staff hope to accomplish in the first year.
Summer 2010: secure full funding for study, including $40,000 from the South Central Idaho Resource Advisory Committee.
September-December 2010: Build and retrofit live traps, hire additional personnel.
January 2011: Begin trapping and monitoring female wolverines. Begin distribution of GPS monitors to winter recreationists.
February-March 2011: Wolverines seek natal dens; crucial data-gathering period.
April-May 2011: Wolverines give birth, then move kits out of natal dens several weeks later. Data-gathering should be completed at this time.
A wolverine is photographed by a remote camera in February as part of an SNRA study of wolverine relatedness and genetic exchange. The animal may be trapped again this winter through the SNRA’s upcoming study of wolverine denning habits. Photo by
