Good News For Some Giant Weasels

North American wolverine | Photo: ucumari photography, some rights reserved

One of North America’s rarest carnivores — with just one individual known to exist in California — is getting a second chance to gain federal protection as an endangered or threatened species.

The North American wolverine, a large and feisty member of the weasel family, was proposed for listing under the federal Endangered Species Act in 2013. The U.S. Fish and Wildlife Service abandoned the attempt to protect the species in August 2014, against the urging of USFWS scientists. Environmental groups sued to overturn that decision two months later. In April of this year federal judge Dana Christensen found in favor of those groups, ruling that USFWS had improperly dismissed concerns that the wolverine is put in danger by climate change, genetic isolation and extremely small population size.

Climate change is an issue because female wolverines seem to require deep snow in order to raise their young. The animals dig birthing dens in deep, persistent snowpack in mountain conifer forests, and generally choose locations where the snow will still be five feet deep in May.

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We don’t know whether California’s mountains are among those used by breeding wolverines. A well-publicized camera trap sighting in the Tahoe National Forest in 2008 — the first California sighting since 1922 — and a more recent one in February 2016 are thought to be of the same male wolverine. There’s no evidence of female wolverines or breeding pairs in California, though scientists haven’t ruled it out.

Wolverine in Tahoe National Forest in February 2016 | Photo: CDFW

In California and elsewhere, as mountains warm along with the rest of the world, there’s a very good chance that five-foot-deep May snowbanks will themselves become an endangered species, and scientists don’t know whether wolverines will be able to adapt and learn to use different childrearing venues. The species’ low numbers — perhaps 300 left in the contiguous U.S. — add to the peril, as does the increasing loss of montane forest habitat to logging and development.

Despite these threats, Noreen Walsh, Regional Director for USFWS’ Mountain-Prairie region ordered her agency to drop the listing attempt in a May 2014 memo, which was leaked to the press two months later. In that memo, Walsh cast doubt on the certainty with which scientists could predict less snow in a warming world, and said the jury was still out on whether the wolverine would necessarily suffer from climate change.

Observers speculated that Walsh’s order came due to pressure from state wildlife agencies in Idaho, Montana and Wyoming, three states with viable remaining wolverine populations. In his ruling this past April, Judge Christensen echoed those sentiments:

Christensen ordered the USFWS to set aside the August 2014 decision and revisit listing the wolverine. Last week, on October 18, the agency did just that, reopening public comment on potentially listing the wolverine as either Threatened or Endangered.

Ahhhhh | Photo: Maia C, some rights reserved

The agency is accepting public comment until November 17, and expects a final ruling by 2018. That’s not soon enough for the wolverine’s advocates. “When it put out its order last April,” Andrea Santarsiere of plaintiff Center for Biological Diversity told Wyoming Public Media, “the court very clearly said to take action at the earliest possible defensible point in time, and the court said for the wolverine, that time is now. That time is not in two years.”

Banner: Sleepy wolverine. Photo: Mats Lindhsome rights reserved

For ongoing environmental coverage in March 2017 and afterward, please visit our show Earth Focus, or browse Redefine for historic material.
KCET's award-winning environment news project Redefine ran from July 2012 through February 2017.

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