FALLS CHURCH, Va. - The U.S. Fish and Wildlife Service announced Tuesday that it is withdrawing a proposal to list the North American wolverine in the contiguous United States as a threatened species under the Endangered Species Act.
The wolverine, a large but elusive member of the weasel family found in the Mountain West, has made a steady recovery in the past half century after hunting, trapping and poisoning nearly extirpated the species from the lower 48 states in the early 1900s.
"While it is clear that the climate is warming, after carefully considering the best available science, the service has determined that the effects of climate change are not likely to place the wolverine in danger of extinction now or in the foreseeable future," the agency said.
As a result, the wolverine does not meet the statutory definition of either a "threatened species" or an "endangered species" and does not warrant protection under the ESA.
Service Director Dan Ashe's decision to withdraw the listing proposal was informed by the consensus recommendation of the agency's three regional directors for the regions encompassing the wolverine's known range in the contiguous United States—the Mountain Prairie, Pacific Northwest and Pacific Southwest regions.
The three directors made the recommendation based on a synthesis of the entire body of scientific evidence. The Service had previously extended the listing deadline by six months due to substantial disagreement regarding the sufficiency or accuracy of the available data relevant to the determination, as allowed by the ESA.
"Climate change is a reality, the consequences of which the Service deals with on a daily basis. While impacts to many species are clear and measurable, for others the consequences of a warming planet are less certain. This is particularly true in the Mountain West, where differences in elevation and topography make fine-scale prediction of climate impacts ambiguous," said Ashe.
"In this case, based on all the information available, we simply do not know enough about the ecology of the wolverine and when or how it will be affected by a changing climate to conclude at this time that it is likely to be in danger of extinction within the foreseeable future."
The Service initially proposed to list the wolverine based on climate-change-model forecasts showing overall loss of spring snow across the range of the species.
However, upon conducting a more thorough review and gathering additional information, the Service said it found that climate change models are unable to reliably predict snowfall amounts and snow-cover persistence in wolverine denning locations.
Additionally, they said, evidence suggests that wolverine populations grew and expanded in the second half of the last century and may continue to expand into suitable, unoccupied habitat.
For example, wolverine sightings outside formerly known habitat occurred in the Sierra Nevada range in California in 2008 and in Colorado in 2012. And in April 2014, a wolverine was seen in the Uinta Range of Utah — the first confirmed sighting of the species in that state in some 30 years.
Currently, the agency said, there is insufficient evidence to conclude that wolverine habitat impacts due to the effects of climate change will affect the population in the foreseeable future.
"While we concluded that the wolverine does not merit Endangered Species Act protection at this time, this does not end our involvement in wolverine conservation," said Ashe. "We will continue to work with our state partners as they manage for healthy and secure wolverine populations and monitor their status. If new information emerges that suggests we should take another look at listing, we will not hesitate to do that."
Wolverine populations currently occur within the contiguous United States in the North Cascades Range in Washington and the Northern Rockies of Montana, Idaho, Wyoming and a small portion of Oregon (Wallowa Range). Populations once existed in the Sierra Nevada of California and the southern Rocky Mountains in the states of Colorado, Wyoming and New Mexico.
Simultaneous with the withdrawal of the listing proposal, the Service is withdrawing a proposed special rule under Section 4(d) of the Act that would have tailored protections to those needed for the conservation of the species, and a proposed nonessential-experimental-population designation for the southern Rocky Mountains of Colorado, New Mexico and Wyoming.
The U.S. Fish and Wildlife Service works with others to conserve, protect, and enhance fish, wildlife, plants, and their habitats for the continuing benefit of the American people. For more information, visit www.fws.gov,