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Know the West

What’s threatening the elusive wolverine?

As snowmobilers fight to preserve their pastime, scientists worry about the future of the species.


Just outside the tiny town of McCall, Idaho, in the sprawling Payette National Forest, Sandra Mitchell drove her snowmobile across a snowy pass. With the loud whine of the machine’s engine ripping through the chilly winter air, she rode between rows of fern, pine and spruce. Soon, the forest opened up to reveal West Mountain with its inviting slopes and sparse clusters of trees. Setting her sights on the summit, she held down the throttle and pointed the nose of her snowmobile upward, a fan of powdery snow spraying out behind her.

At the peak, Mitchell glided to a stop, turned off the engine and gazed out over the silent snow. “You get to see nature dressed in white,” she said. “It’s breathtaking.”

That was just the first of many times that Mitchell rode up West Mountain. Today, around 27 years later, she is director of public lands for the Idaho State Snowmobile Association. In her many years of snowmobiling, she has seen a lot of wildlife: a male moose with a rack of antlers, wolf tracks in the snow. But neither she nor any of her snowmobiler friends has ever seen the animal whose tenuous status could lead to the closure of backcountry areas to recreationists like herself: the elusive wolverine.

Jia Sung/High Country News

Wolverines require a lot of land and snow in order to survive, making places like the Payette National Forest in west-central Idaho a perfect home. But this forest is also a hub for winter sports, drawing backcountry enthusiasts from across the nation. In 2007, however, a team of Forest Service employees proposed closing approximately 15,000 acres — less than 1% of the entire forest — to snowmobilers, partly to protect the wolverine. When Mitchell heard this, she balked. “It was shocking when we saw the proposal,” she said. The Idaho State Snowmobile Association claimed that it wasn’t based on sound science. “We’ll do what the science tells us,” she said, “but once the land is closed, it’s always closed. We need to work for other management options.”

In 2010, Mitchell and her team joined forces with eight other groups, including the Idaho Department of Fish and Game and the Sawtooth National Forest in central Idaho, in a collaborative effort to study how backcountry sports, including snowmobiles and backcountry skiing, impact wolverines.

But instead of generating a clear answer on how to balance recreation and wildlife, the science may have simply bolstered past convictions. The research — which was published in February 2019 and concluded that winter recreation displaces wolverines — has fueled an ongoing lawsuit regarding a proposed closure in the Sawtooth National Forest. “People are interpreting the research based on their own agendas,” said Kimberly Heinemeyer, a lead scientist at the Round River Conservation Studies, the ecological research and education nonprofit that spearheaded the study.

Now, snowmobilers like Mitchell are responding by suing the U.S. Forest Service, hoping to preserve one of their most cherished pastimes. Meanwhile, researchers worry that if the Forest Service doesn’t take action soon to protect wolverine habitat, the animal may disappear from the Lower 48. 

FOR IDAHOANS LIKE MITCHELL, snowmobiling is woven into the cultural fabric of the state. In 1971, a group of nine snowmobilers rode into the woods near Pine, Idaho, one weekend and returned with the idea for the Idaho State Snowmobile Association. Around 20 years later, Mitchell became an integral part of the community and has since helped welcome thousands of new members. Today, snowmobiling generates millions of dollars within the state of Idaho. During the 2015-2016 winter season, snowmobile owners spent close to $200 million in lodging, food, equipment and more, and supported more than 4,000 retail and other jobs, according to a study by Boise State University.

Still, conservationists like the Idaho Conservation League’s Brad Smith believe that snowmobilers need to be more conscious of where they ride when they enter areas where sensitive species, like wolverines, are known to roam.

Wolverines are solitary animals that live in remote, cold places like Idaho, Montana and Alaska. Males can weigh up to 40 pounds — stocky creatures, with long, coarse fur, sharp claws and spectacular strength. By nature, they have very low-density populations with home ranges of up to 600 square miles. They’ve been known to travel up to 15 miles a day in search of food, which explains their scientific name, Gulo gulo, from the Latin word for “glutton.” Between February and May, in order to den and give birth, female wolverines require deep snow, which keeps their offspring safe from predators and buffers them from frigid winter temperatures. After a long history of fur trapping — a practice that is now banned in most states, including Idaho — there are only an estimated 250 to 300 wolverines left in the Lower 48. Today, wolverines have been reported in 77% of Idaho’s counties — most, if not all, of their in-state historic habitat — which includes snowy, mountainous areas where Mitchell and thousands of others snowmobile.

Today, wolverines have been reported in 77% of Idaho’s counties — most, if not all, of their in-state historic habitat — which includes snowy, mountainous areas where Mitchell and thousands of others snowmobile.

This interaction between winter recreationists and wolverines may harm the species, according to the study in the journal Ecosphere. Over the span of six winters, researchers investigated the responses of GPS-tagged wolverines in Idaho, Wyoming and Montana to snowmobilers and backcountry skiers. They found that wolverines avoided areas used by recreationists, with females being particularly sensitive to backcountry activity. Bit by bit, they were losing their habitat.

Reactions to the research have been mixed. Hilary Eisan, the policy director for the nonprofit Winter Wildlands Alliance, which represents backcountry skiers and outdoor recreation on public lands, argues that the study provides clear evidence that winter sports threaten wolverine habitat. Mitchell, on the other hand, claims the study only shows the need for more studies. “Overall, we were disappointed that there were not more conclusive results,” she said. “Wolverines move all the time, so them changing their habitat due to snowmobiles is not necessarily conclusive.”

“I’m concerned if we don’t pay attention to it now, we could lose wolverines before we even really know them.”

However, the species may not have time to wait for more research. Climate change is already hurting wolverines by reducing spring snowpack and female denning areas, said Jeffrey Copeland, a former researcher for the U.S. Department of Agriculture and one of the study’s authors. “I’m concerned if we don’t pay attention to it now, we could lose wolverines before we even really know them,” he said.   

It was this conflict that led to the current lawsuit in the district court of Idaho. Using an earlier published version of the study, the Fairfield Ranger District in the Sawtooth National Forest closed 72,447 acres of land — 17% of the Fairfield Ranger District and approximately 3% of the entire forest — to snowmobilers December 2018. The area was routinely used by snowmobilers, thus prompting the Idaho State Snowmobile Association to sue the Sawtooth and the Forest Service. The association argued that the decision “assumes that snowmobiling in these closed areas will have adverse environmental impacts without any solid scientific evidence.” Oral arguments for the case are expected to begin as early as this spring. 

To strengthen their case, snowmobilers asked Mike Schlegel, a retired wildlife research biologist for the Idaho Department of Fish and Game, to review the land closure proposal. Schlegel believes the Forest Service is being too conservative in its management plan and that there is no direct evidence that winter recreationists directly harm wolverines. Instead, he recommends mapping out female denning sites and educating snowmobilers to avoid those critical areas.


Mitchell and Heinemeyer, the lead author on the wolverine study, are also working with backcountry groups to create land-management recommendations that can be used by both the Forest Service and recreationists. The process, still in its early stages, aims to publish a proposal that mitigates any harm to wolverines. “I don’t want the wolverine to be the cause of lawsuits and a bunch of fights over land use,” said Heinemeyer. 

But Mitchell fears there may be more disputes ahead. “I’m worried that other national forests will close to snowmobilers,” she said. “We’ll have to take it one forest at a time.” And given the changing winter landscape, such conflicts may become more frequent. With warmer winters, later snowfall and earlier spring rain, snowy areas for winter recreationists are shrinking, and there’s a higher chance of disturbing wildlife.

With this in mind, conservationists worry about future protections for the wolverine, which is currently in the midst of another legal battle as to whether it will be listed under the Endangered Species Act. Last November, the U.S. Fish and Wildlife Service failed to meet its deadline for a listing decision. Subsequently, a group of nine conservation groups have threatened to sue the Trump administration.     

“In the snowmobiling community, there is a great respect for wildlife.”

Yet even scientists who have spent their careers studying the animal say the wolverine remains an enigma. This is echoed by backcountry enthusiasts like Mitchell, who has never seen a wolverine, and likely never will. “I would be thrilled to death to see one,” Mitchell said. “What an amazing little critter.”

When I asked if the new research on wolverines has changed how she interacts with the landscape while snowmobiling, she responded immediately, “It does. I definitely am more conscious of animals.” Now, Mitchell says that she tries to stay away from areas where they may reside. “In the snowmobiling community, there is a great respect for wildlife,” she said. 

So far, though, that respect has not translated to action in the broader community of snowmobilers, and it is unlikely to be enough to protect the wolverine. Snowmobilers like Mitchell still plan to spend their winters trekking out to desolate places far away from marked trails, and, according to the science, this means riding through wolverine habitat.

For a species already under threat, this may be the breaking point. “The stakes are higher,” Eisan said. “We can’t just sit back and let it be a free-for-all.”   

Helen Santoro is an HCN fellow based in Gunnison, Colorado, who covers science and wildlife. She enjoys backcountry skiing and, when she has the time, camping in the frigid winter temperatures. Email her at [email protected] or submit a letter to the editor.