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Conservation Groups Sue Federal Agency to Protect Wolverines

Climate change has led to loss of spring snowpack, endangering feisty predator

After more than a century of trapping and habitat loss, wolverines in the lower 48 have been reduced to small, fragmented populations in Idaho, Montana, Washington, Wyoming and northeast Oregon.

Erik Mandre/Shutterstock
October 13, 2014
Missoula, MT —

Eight conservation groups joined forces today in a legal challenge of the U.S. Fish and Wildlife Service’s decision to abandon proposed protections for the wolverine, a rare and elusive mountain-dwelling species with fewer than 300 individuals remaining in the lower 48. 

In February 2013, the Fish and Wildlife Service proposed to list the wolverine as a threatened species under the Endangered Species Act after the agency’s biologists concluded global warming was reducing the deep spring snowpack pregnant females require for denning.

But after state wildlife managers in Montana, Idaho and Wyoming objected, arguing that computer models about climate change impact are too uncertain to justify the proposed listing, in May 2014 the Service’s Regional Director Noreen Walsh ordered her agency to withdraw the listing, ignoring the recommendations of her own scientists. The reversal came despite confirmation by a panel of outside experts that deep snow is crucial to the ability of wolverines to reproduce successfully. The agency formalized that withdrawal in a final decision issued Aug. 13.

The coalition of eight conservation groups, represented by Earthjustice, is suing to overturn that decision filed the lawsuit today in federal district court in Missoula, Mont.

“The wolverine is a famously tough creature that doesn’t back down from anything, but even the wolverine can’t overcome a changing climate by itself,” said Earthjustice attorney Adrienne Maxwell. “To survive, the wolverine needs the protections that only the Endangered Species Act can provide.”

The groups bringing the lawsuit are the Center for Biological Diversity, Conservation Northwest, Friends of the Clearwater, Greater Yellowstone Coalition, Idaho Conservation League, Jackson Hole Conservation Alliance, Klamath-Siskiyou Wildlands Center, and Rocky Mountain Wild.

“The denial of protection for the wolverine is yet another unfortunate example of politics entering into what should be a purely scientific decision,” said Noah Greenwald, endangered species director at the Center for Biological Diversity. “All of the science and the agency’s own scientists say the wolverine is severely endangered by loss of spring snowpack caused by climate change, yet the agency denied protection anyway.”

"The best available science shows climate change will significantly reduce available wolverine habitat over the next century, and imperil the species,” said Jackson Hole Conservation Alliance’s Siva Sundaresan. “As an agency responsible for protecting our wildlife, FWS should not ignore science and should make their decisions based on facts and data.”

“Wolverines in the Clearwater region are particularly vulnerable because the elevations here are less than those elsewhere in the Northern Rockies,” said Gary Macfarlane of Friends of the Clearwater. “It would be a great loss if this fearless critter were to disappear from the wild Clearwater country.”.

“One of the most important things that we can do to get wolverines on the road to recovery in the face of a warming climate is to get them back on the ground in mountain ranges where they once lived,” said Megan Mueller, senior conservation biologist with Rocky Mountain Wild. “We are disappointed by the Service’s decision not to list wolverines under the Endangered Species Act as protections would have helped to facilitate such efforts in Colorado and beyond.”

“The remote, rugged, and snowy North Cascades are ideal wolverine habitat,” said Dave Werntz, Science and Conservation Director with Conservation Northwest. “Protection under the Endangered Species Act will help wolverine survive a warming climate, shrinking snowpack, and increasingly fragmented habitat.”

Read the legal document.


The wolverine, the largest land-dwelling member of the weasel family, once roamed across the northern tier of the United States and as far south as New Mexico in the Rockies and Southern California in the Sierra Nevada range. After more than a century of trapping and habitat loss, wolverines in the lower 48 have been reduced to small, fragmented populations in Idaho, Montana, Washington, Wyoming and northeast Oregon.

With no more than 300 wolverines remaining in these regions, the species is at direct risk from climate change because wolverines depend on areas that maintain deep snow through late spring, when pregnant females dig their dens into the snowpack to birth and raise their young. Snowpack is already in decline in the western mountains, a trend that is predicted to worsen. Wolverine populations also are threatened by trapping, human disturbance, extremely low population numbers resulting in low genetic diversity, and fragmentation of habitat.

The groups challenging the Service’s determination pointed out that the agency disregarded well-established scientific evidence, including the recommendations of its own scientists, in speculating that the wolverine might be capable of withstanding the projected loss of 63 percent of its snowy habitat in the lower 48 by the year 2085. Contrary to the Service’s speculation, every one of the 562 verified wolverine den sites in North America and Scandinavia occurred in snow; 95 percent of worldwide summer wolverine observations and 89 percent of year-round wolverine observations fell within areas characterized by persistent spring snowpack. Elimination of this snowy habitat due to warming temperatures presents a direct threat to the wolverine’s survival — a danger compounded by the increasing isolation and fragmentation of wolverine habitats that threatens remaining populations with localized extinctions and inbreeding.

On May 17, the assistant director for the Fish and Wildlife Service’s Rocky Mountain region recommended protection for the wolverine, concluding that the agency's scientists had not found “any other peer-reviewed literature or other bodies of evidence that would lead us to a different conclusion. While we recognize there is uncertainty associated with when population effects may manifest themselves, any conclusion that there will not be population effects appears to be based on opinion and speculation. In our opinion that would not represent the best available scientific or commercial data available.” Despite these strong conclusions, the Fish and Wildlife Service reversed course and withdrew proposed protection for the wolverine.


Adrienne Maxwell, Earthjustice, (406) 586-9699