U.S. Fish and Wildlife Service (FWS) Director Dan Ashe announced on August 12 that the agency was withdrawing a proposal to list wolverines as a threatened species under the Endangered Species Act (ESA), according to the Wildlife Management Institute. Agency leadership determined that the effects of climate change were uncertain on the species at this time and therefore did not warrant federal listing. However, the decision countered recommendations by agency biologists and conclusions of an expert panel of biologists convened in April.

"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."

Wolverines are highly elusive predators found in high elevation forests in the Mountain West including the North Cascades in Washington and the Northern Rocky Mountains of Idaho, Montana, Oregon and Wyoming; individuals have also been seen in Colorado and California but have not established breeding populations. Currently there are about 300 known individuals but the species has been slowly recovering since facing near extirpation early in the last century. In February 2013, the FWS proposed the species for listing under the ESA due to the anticipated loss of snowpack within the wolverine's range resulting in reduced denning habitat.

The agency proceeded with public comment periods and public hearings in 2013. Last fall, the Western Association of Fish and Wildlife Agencies requested a delay in the listing decision and state biologists expressed concerns about listing the species based on climate models, citing the current historically high population levels. In February 2014, the FWS extended the deadline for the final listing decision and convened an expert panel with an objective to "better understand the strength of the relationships between climate change, wolverine habitat, and future wolverine population trends through dialogue with an expert panel." That panel expressed "cautious optimism" that the species might expand its range in the short term, however all nine panelists "expressed pessimism" for the species over the rest of the century due to the impacts of climate change on habitat.

Agency regional leadership then proceeded with reviewing the breadth of available scientific studies and climate models. During that review, director of the FWS' Mountain-Prairie region, Noreen Walsh, expressed uncertainties "about the degree to which we can reliably predict impacts to wolverine populations from climate change." The final listing decision concluded that climate change models are unable to reliably predict snowfall amounts or snow-cover persistence in denning locations. That decision led to the withdrawal of the listing petition.

In late July, the Society for Conservation Biology and the American Society of Mammalogists commented on Walsh's determination. The organizations' comments "identify serious flaws in the Fish and Wildlife Service's listing determination process. They also highlight a troubling pattern of disregard for the best available science in making these decisions." In addition, a number of environmental organizations have already signaled their intent to file suit to challenge the FWS decision.

The FWS decision leaves management of wolverines to the state fish and wildlife agencies, some of which are expressing their support of the decision. Bill Bates, wildlife section chief for the Utah Division of Wildlife Resources (DWR) was quoted in the Salt Lake Tribune stating: "We brought up issues during meetings here in Salt Lake and we appreciate [the FWS] being able to take a look at those points and reevaluate their decision. We appreciate the fact they are willing to put trust in the states and allow us to manage wolverines? It allows us to look more in depth what might be out there and allows us to begin the process of a management plan." (jas)