Rare mammals found in North Cascades
High in the mountains above the Methow Valley lives a small population of rare wolverines, one of the most elusive mammals in North America.
The North Cascades are one of the few areas in the United States where wolverines are still found. But their snowy alpine habitat in the North Cascades and elsewhere in the West is becoming increasingly fragmented and degraded due to human activity and climate change.
The imperiled species will gain new protections with a recent decision by the U.S. Fish and Wildlife Service (FWS) to designate the wolverine as a threatened species under the Endangered Species Act (ESA) in the lower 48 states.
The decision by FWS comes after decades of considering the wolverine (Gulo gulo luscus) for protection as a threatened or endangered species, and will provide a recovery plan for wolverines, which rely on high-elevation mountain snowpack for their survival.
“Current and increasing impacts of climate change and associated habitat degradation and fragmentation are imperiling the North American wolverine,” said Hugh Morrison, FWS Pacific regional director.
“Based on the best available science, this listing determination will help to stem the long-term impact and enhance the viability of wolverines in the contiguous United Sates,” Morrison said in an announcement of the decision.
With the listing decision on Nov. 29, FWS also issued an interim rule under a section of the ESA that allows the agency to establish special regulations for a threatened species.
The ESA prohibits the “take” (harming or killing) of threatened species. The interim 4(d) rule issued by FWS exempts certain activities from the prohibition on harming or killing wolverines.
Those activities include research, lawful trapping for other species, and forest management actions undertaken to reduce wildfire risk. FWS has opened a 60-day comment period through Jan. 29, 2024, on the rule.
A coalition of conservation groups originally petitioned to list the wolverine as threatened almost 30 years ago, in 1994, and again in 2000. For decades, FWS has been see-sawing on protections for wolverines, sometimes recommending protections and sometimes deciding they are not necessary.
Earthjustice and the groups it represents won every case they filed on behalf of the wolverine, either through judicial rulings in their favor or through favorable settlement agreements.
The most recent ruling by a federal judge in June of 2022 invalidated a Trump administration decision to deny protections, and gave FWS 18 months to determine whether wolverines deserve to be listed as threatened or endangered. The agency’s Nov. 29 decision came just before that deadline.
“This long-awaited decision gives the wolverine a fighting chance at survival,” said Timothy Preso, an Earthjustice attorney who represented conservation groups in the long-running legal campaign to protect the wolverine. “There is now hope for this icon of our remaining wilderness,” Preso said in a news release from the conservation organizations.
“I’m thrilled that the Fish and Wildlife Service finally followed the science and granted wolverines the federal protections they need to survive and recover,” said Andrea Zaccardi, of the Center for Biological Diversity. “Like so many other species, wolverines waited far too long for federal protections, but I’m overjoyed that they’re finally on the path to recovery.”
Female wolverines dig dens in the snow to give birth and raise their young, and rely on deep, high-elevation snowpack that lasts into spring and summer. Scientists predict climate change will increasingly affect snowfall patterns throughout wolverine range in coming years, significantly reducing snowpack and available wolverine habitat.
In September of this year, FWS updated a species status assessment for wolverines to reflect new information since a previous assessment in 2018, and to inform the decision on listing the wolverine as threatened.
The new assessment emphasized wolverines’ dependence as a “snow-adapted species” on persistent spring snow for survival, including denning and raising their young.
The assessment found that fewer wolverines are dispersing from the southern Canadian Rockies into the U.S. than in the past, due to barriers caused by major highways, and “unsustainable trapping levels in Southern Canada” that reduced the population.
Connectivity with wolverine populations in Canada is “essential to long-term viability of wolverines in the lower 48 states,” and loss of that connectivity has reduced the genetic diversity and adaptive capacity in the U.S. population of wolverines, according to FWS.
The updated assessment found that human development in valley bottoms between core wolverine habitats limits dispersal and connectivity between wolverine populations.
In addition, winter recreation negatively affects wolverines and their habitat, and is “likely to increase and become more concentrated in the future as snow-covered areas decline due to climate change,” the status assessment said.
Candidate species in Washington
The largest terrestrial member of the weasel family, wolverines can weigh up to 35 pounds and are notoriously fierce and powerful for their size.
Wolverines 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, only about 300 wolverines are believed to live in the lower 48 states today as small, fragmented populations in Washington, Idaho, Montana, Wyoming, and northeast Oregon.
In Washington, wolverines are considered a candidate species for listing as threatened or endangered under state law, according to Washington Department of Fish and Wildlife. They are found in high-elevation landscapes from North Cascades National Park and Okanogan-Wenatchee National Forest (including the Methow Valley Ranger District), south to Mount Adams on the Gifford Pinchot National Forest.
Wolverines were extirpated from Washington in the mid-1900s as a result of hunting and trapping, however they became reestablished in the North Cascades beginning in the 1990s and in the South Cascades by 2008.
A 10-year study from 2005-2015 conducted by wildlife biologists based in the Methow Valley trapped and placed radio collars on about 14 wolverines in the North Cascades to learn more about their behavior and habitat. Scott Fitkin, a wildlife biologist with the Washington Department of Fish and Wildlife (WDFW), was part of the research team that included John Rohrer, a U.S. Forest Service biologist and field coordinator for the study.
The population in the Cascades is estimated by state wildlife officials to be less than 25 wolverines.
With wolverines now listed as a threatened species, federal agencies like the U.S. Forest Service must confer with FWS on any action they take that might harm wolverines. The health and safety of wolverines and their habitat must also be considered in planning decisions that could destroy or degrade their critical habitat.
However, critical habitat designation for wolverines is not part of the recent FWS listing decision. FWS said it has an additional year from publication of the listing to designate critical habitat.
FWS said the interim 4(d) rule allows protections to be “tailored to the wolverine’s conservation needs” while “reducing undue regulatory burden.” The rule is intended to “streamline ESA compliance for actions that result in low levels of take but do not threaten a species’ continued existence.”
The agency said the species’ conservation would not likely be harmed by exempting take related to scientific research, forest management activities to reduce the risk or severity of wildfire, and wolverines trapped and killed incidental to legal trapping for other species.
The decision on the wolverine’s listing status is final, but FWS is asking for public comment on the prohibitions and exceptions provided by the interim 4(d) rule before making the rule final.
Information on the rule and how to submit comments can be found at www.regulations.gov/ by searching under docket number FWS-R6-ES-2012-0107. The 60-day comment period opened Nov. 30 and comments must be received by Jan. 29.
For more information, a frequently asked questions document is available at: www.fws.gov/question-answer/us-fish-and-wildlife-service-announces-final-rule-list-north-american-wolverine.