Climate change and genetic isolation threaten famously tough predator
April 4, 2016
MISSOULA, Mont.— Describing the wolverine as a “snow-dependent species standing squarely in the path of global climate change,” a federal judge today overturned an August 2014 decision by the U.S. Fish and Wildlife Service refusing to grant this rare and elusive species any protection under the Endangered Species Act (ESA).
The ruling by U.S. District Court Judge Dana Christensen rejected the Service’s determinations that climate change, an extremely small population size—there are only approximately 300 wolverines left in the northern Rockies and north Cascades—and genetic isolation do not threaten the wolverine’s survival in the lower-48 states.
“This decision gives the wolverine a fighting chance at survival,” said Earthjustice attorney Timothy Preso, who represented eight conservation groups in the case before Judge Christensen. “There is now hope for this icon of our remaining wilderness.”
Today’s ruling passes a harsh judgment on the Fish and Wildlife Service for an eleventh-hour reversal in considering new legal protections for the wolverine. In February 2013 the Fish and Wildlife Service proposed to list the wolverine as a threatened species under the ESA after the agency’s biologists concluded global warming was reducing the deep spring snowpack pregnant females require for denning.
But 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. Then, 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 agency formalized that withdrawal in a final decision issued in August 2014.
In today’s ruling, Judge Christensen addressed the question of why the Service flip-flopped on this key conservation issue: “[T]he Court suspects that a possible answer to this question can be found in the immense political pressure that was brought to bear on this issue, particularly by a handful of western states. The listing decision in this case involves climate science, and climate science evokes strong reactions.”
The judge also directed the Service to act promptly to correct its erroneous findings: “It has taken us twenty years to get to this point. It is the undersigned’s view that if there is one thing required of the Service under the ESA, it is to take action at the earliest possible, defensible point in time to protect against the loss of biodiversity within our reach as a nation. For the wolverine, that time is now.”
The groups represented by Earthjustice in the wolverine case 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. They praised today’s court decision.
“Wolverines are the mountain devils of the west and they require snow,” said Tanya Sanerib an attorney with the Center for Biological Diversity, “The court rebuffed the Fish and Wildlife Service’s rejection of climate change threats to wolverines as ‘bordering on the absurd.’”
“Today’s decision restores scientific integrity to wolverine management,” said Caroline Byrd, Executive Director of Greater Yellowstone Coalition. “This increasingly rare and elusive animal represents the wildness that is still found today in Greater Yellowstone and we are committed to ensuring wolverines receive the protections they deserve.”
“We are pleased that the court sided with us,” said Brad Smith of the Idaho Conservation League. “The wolverine is one of Idaho’s rarest animals. Now we need to work toward the protections that are needed to recover wolverines.”
“This decision is great news for wolverines in the Clearwater Basin. Because elevations here are not as high as much of the rest of the Rockies, wolverines in the Clearwater are particularly threatened by climate change and other human impacts,” said Gary Macfarlane of Friends of the Clearwater.
“Today’s decision is welcome news for anyone wishing to observe wolverine in remote, rugged and snowy mountain landscapes,” said Dave Werntz, Science and Conservation Director with Conservation Northwest. “The future of wolverine in the North Cascades and elsewhere is now a bit brighter.”
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 that challenged 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.