In the dead of winter, female wolverines dig elaborate, multi-chambered dens to raise their young, choosing sites where snowpack lasts well into the spring. But snowpack in the Northern Rockies is almost certain to decline as the climate warms, jeopardizing their chances for successful reproduction. There are fewer than 300 wolverines in the Lower 48, and models show that they could lose 31 percent of their habitat by 2045 and 63 percent by 2085. And so, in February 2013, the U.S. Fish and Wildlife Service proposed adding the "mountain devils" to the endangered species list.
The science behind the proposal has not changed, but the agency's position on it has. Mountain-Prairie Regional Director Noreen Walsh advocated against a speculative listing in a memo released by environmentalists in July, citing uncertainty as to exactly why wolverines need a persistent snowpack to reproduce and how its loss would harm the animals. Though scientists recommended listing wolverines as threatened, agency leader Dan Ashe defended her position – a strong indication of which way the final decision, due in early August, will go.
Wolverines would have been the first species in the Lower 48 thrust onto the endangered species list by climate change. A listing would have helped validate the use of climate models to develop strategies to protect animals against future threats. And it would have been unusual because, unlike most of the species the act safeguards, wolverines, though rare, are not thought to be declining.
Idaho, Montana and Wyoming – the states that anchor the animal's range in the Lower 48 – dreaded the prospect of a listing and the public-land restrictions it could bring, while environmentalists cheered it on. In practical terms, though, would formal protections really help wolverines? Can a law that was designed to rescue species from discrete, localized threats also protect them from the more diffuse hazards of a warming world?