BILLINGS, Mont. -- A top federal wildlife official said there’s too much uncertainty about climate change to prove it threatens the snow-loving wolverine -- overruling agency scientists who warned of impending habitat loss for the "mountain devil."
There’s no doubt the high-elevation range of wolverines is getting warmer, U.S. Fish and Wildlife Service Regional Director Noreen Walsh said. But any assumption about how that will change snowfall patterns is "speculation," she said.
Walsh told her staff to prepare to withdraw a proposal to protect the animals under the Endangered Species Act.
Wildlife advocates said the move was a bow to pressure from Western states that don’t want wolverines protected. Walsh said her stance "has not been influenced in any way by a state representative."
More broadly, it points to the potential limitations in the use of long-range climate forecasts to predict what will happen to individual plant and animal species as global temperatures rise.
Walsh’s comments were contained in a May 30 memo obtained by the Center for Biological Diversity, an environmental group. Fish and Wildlife Service spokesman Chris Tollefson confirmed that Walsh authored the document.
Agency Director Dan Ashe will have the final say, with a decision due Aug. 4.
Wolverines max out at 40 pounds and are tough enough to stand up to grizzly bears.
Federal biologists last year proposed protections for an estimated 300 wolverines in the Lower 48 states. At that time, Walsh said "scientific evidence suggests that a warming climate will greatly reduce the wolverine’s snowpack habitat."
In the recent memo, she expressed the opposite view: "Due to the uncertainty of climate models, I cannot accept the conclusion about wolverine habitat loss that forms the basis of our recommendation to list the species."
Walsh, also a biologist, said she reached that conclusion after reviewing the latest science on wolverines and consulting with other agency officials.
Most of that science already was available when protections were first proposed, leading the Center for Biological Diversity to criticize the about-face.
The likelihood of climate change harming wolverines was too great to delay action because of any lingering uncertainties, said the group’s climate science director, Shaye Wolf.
The government already has declared that global warming imperils other species, including polar bears, ringed seals and bearded seals.
"Climate change is driving some iconic species toward extinction, and many species are in trouble," Wolf said. "It’s a very bad turn of events that the Fish and Wildlife Service has chosen to ignore the expertise of its own scientists" on wolverines.
Agency officials said Monday that Walsh’s memo was just one step in its deliberations on the animal.
Once found throughout the Rocky Mountains and in California’s Sierra Nevada mountain range, wolverines were wiped out across most of the U.S. by the 1930s due to unregulated trapping and poisoning campaigns. In the decades since, they have largely recovered in the Northern Rockies but not in other parts of their historical range.
In some areas, such as central Idaho, researchers have said suitable habitat could disappear entirely.
Wolverines are found in the North Cascades in Washington and the Northern Rocky Mountains in Idaho, Montana, Oregon and Wyoming. Individual wolverines have also moved into California and Colorado but have not established breeding populations. Larger populations persist in Alaska and Canada.
Officials from states including Montana, Utah and Idaho have objected to more protections, saying the animal’s population has been increasing in some areas.
Two members of an independent peer review panel also raised questions about the science behind last year’s proposal. They suggested that no direct link could be made between warming temperatures and less habitat.
Panelist Audrey Magoun, a researcher based in Alaska, said shifting weather patterns could mean more snowfall, not less, in the mountains where most wolverines den. She said Monday that she was not taking a position on whether protections were needed and that there was enough time to determine that through additional research before any long-range threats come to pass.
Wolverines were twice denied protections under the Bush administration. In 2010, the Obama administration delayed action and said other imperiled animals and plants had priority over wolverines.