Not enough evidence of climate harm to list wolverines, says Fish and Wildlife
Climate change is a real force disrupting wildlife populations. But for the 300 or so wolverines living in the lower 48, there’s still not enough evidence of present or future danger to protect them under the Endangered Species Act, the U.S. Fish and Wildlife Service announced Tuesday.
In February 2013, the agency proposed to list wolverines as threatened because climate change is eating away at spring snowpack in the northern Rockies, which in turn will harm wolverines since they raise their young in snowy dens. After more than a year of analysis, the agency officially withdrew its proposal this week.
It’s an important listing decision, not only for dictating future wolverine management, but also for gauging the Fish and Wildlife Service’s tolerance for using climate models to list species.
Most ESA listings result from threats that are already happening, such as habitat loss from human development. But the proposal to list wolverines was based largely on predictions of how future snowpack will shrink in their high-alpine denning regions. While the agency has always used ecological models to evaluate risks to sensitive species, climate predictions that play into the wolverine proposal add yet another layer of uncertainty.
Listing decisions based primarily on the threats of climate change also attract a new level of scrutiny since there have been so few. Thus far, polar bears, ringed seals and bearded seals are the only species listings primarily based on warming threats to their habitat.
If Tuesday’s decision is any indication, the challenge of predicting highly specific, small-scale climate impacts may prove a major roadblock to endangered species protection for other animals as well. For example, a judge in Alaska recently ruled that bearded seals, which were considered threatened because of melting sea ice, should not have been listed.
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The wolverine proposal was also out of the ordinary because these animals are not currently declining, as far as anyone knows. In addition to facing climate-related threats, wolverines were trapped and poisoned, wiping them out over much of the West in the early 20th century. Now they may even be recovering and some biologists think they could be expanding their range into places like Utah and Colorado.
While climate models predict spring snow cover loss across the wolverine’s range by the end of the century, “we don’t know that this loss of snow will equate to a commensurate loss of wolverine habitat or when it might limit wolverine populations,” said U.S. Fish and Wildlife Service director Dan Ashe during a teleconference with reporters on Tuesday. The problem, from the agency’s perspective, is that there’s not enough specific information about how and why wolverines choose their snowy den sites to predict how devastated their habitat will be as the Earth continues to warm.
Ashe framed the agency’s reversal as a case of two sets of scientists evaluating the same body of research and reaching different, yet reasoned, conclusions – which isn’t that unusual. But environmental groups and some scientists see the agency’s reversal as a bow to political pressure, namely from the states of Montana, Wyoming and Idaho, all of which opposed a listing.
“In this case the Service is using uncertainty as an excuse to override the expert judgment of its owns scientists and that’s a really bad precedent,” Shaye Wolf, climate science director for the Tucson-based Center for Biological Diversity, said in an interview last month. CBD is one of the environmental groups involved in the legal settlement that spurred the U.S. Fish and Wildlife Service to propose listing wolverines last year. Nine organizations, including CBD, are now planning to challenge the listing decision in court.
Sarah Jane Keller is a High Country News correspondent based in Bozeman, Montana. She tweets @sjanekeller.
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