Report: Shrinking snowy areas may not be enough for both wolverines, outdoorsmen

Idaho’s backcountry skiers, snowmobilers and wolverine population could be competing for territory on the same shrinking snowfields in years to come, research compiled by the state suggests.

Some climate models project that Idaho will lose 40 percent of its spring snow by 2060 and about 80 percent by the century’s end. Given wolverines’ dependence on cold, snowy habitat, and a growing demand for winter recreation, conflicts could develop, according to the Idaho Department of Fish and Game’s draft wolverine conservation plan.

Wolverines are adapted to harsh mountain environments, with frost-free hair and a metabolic rate that can’t tolerate temperatures above 70 degrees, said Beth Waterbury, team leader for the draft plan. The species is thinly distributed across North America’s arctic, boreal and alpine forests. The fierce-looking critters resemble small bears, but they’re actually members of the weasel family, along with otter and mink.

Between 250 and 300 wolverines are believed to inhabit the Rocky Mountains of Idaho, Montana and Wyoming, and Washington’s North Cascade Range. Wolverine numbers have rebounded since the early 1900s, but they remain candidates for federal endangered species listing. In Idaho, wolverines from Canada and large wilderness areas have helped sustain the state’s wolverine population, according to the draft plan.

But climate change is expected to alter the landscape wolverines need for survival. Of particular interest to researchers are the secluded, high-elevation sites where female wolverines den in late February, Waterbury said. They pick sites where the snow lingers until mid-May.

“People are still kind of speculating on what’s driving that,” she said. Among the theories: The isolation may protect wolverine kits from predators, and the snow provides insulation from frigid temperatures.

A smaller snowpack is likely to drive wolverines and backcountry recreationists to the same sites, so it’s imperative to know how wolverines react to winter recreational use, the state’s draft plan said.

Some of that field research has begun in central Idaho through studies conducted by the U.S. Forest Service and Round River Conservation Studies with various partners, including the state of Idaho and the Idaho State Snowmobile Association. But more work is needed to understand how recreation influences wolverine distribution and reproductive success, the draft plan said.

Given the small numbers of wolverines, it will take at least several more years of data collection before researchers have enough data to draw conclusions, Waterbury said.

The draft plan supports continuation of that work, along with cooperative efforts among Western states to identify the travel corridors that far-flung wolverine populations need to maintain genetic diversity.

Public comments will be accepted through June 9 on the draft plan, which also recommends:

• Working to reduce the number of wolverines accidentally taken through trapping and increasing hunters’ ability to identify wolverines, which are sometimes mistaken for badgers.

• Providing safe highway crossing sites for wolverines and other wildlife.