Wolverines, wily animals that are the subjects of legend, have a healthy population in Arctic Alaska, but they need a lot of undisturbed habitat for their population to stay that way.
That was shown in a recently published study in the Journal of Wildlife Management, which gave the first estimate of North Slope wolverine numbers and densities in several decades.
The study, by Thomas Glass, a University of Alaska Fairbanks biologist, and Martin Robards, a Fairbank-based biologist with the Wildlife Conservation Society, tracked animals that were given radio collars after being lured by bait stations. The biologists observed animals through prepositioned cameras.
The combination of radio-dollar and camera data collected from 2017 to 2022 led to a mean estimate of 488 wolverines on the North Slope, with an estimated density of two wolverines per 1,000 square kilometers.
It is a healthy enough number to support the amount of hunting and trapping that occurs there, the study concludes. But it is much lower than the densities measured the last time such research was conducted to estimate North Slope populations, which was four decades ago, in the PhD dissertation by biologist Audrey J. Magoun. That earlier estimate was for a North Slope population of at least 821, with as many as 20 wolverines per 1,000 square kilometers.
Estimating wolverine population sizes and densities in Alaska is challenging, Glass said. It has to be done in winter, and since there are not many wolverines, scientists have to cover a lot of ground, he said.
The new study uses data from three areas on the central North Slope. The 1985 study that found a higher wolverine density focused on a slightly different part of northern Alaska.
“I think any time you try to study wolverines, it’s a huge logistical undertaking,” he said. “Fortunately, they are pretty responsive to bait once you do get out there.”
The differences could reflect an overall population decline. Wolverine populations go through cycles, as do those of other mammals, and those cycles are linked at least in part to abundance of prey, Glass and Robard said. Caribou make up a lot of the diet of North Slope wolverines, and the caribou population declines of recent years may have affected wolverines, they said.
Despite the difference in the new study’s numbers and the numbers calculated in the 1980s, the wolverine population on the North Slope is healthy, they said.
“The feeling right now is we’re in a reasonably good position. That doesn’t say that they can’t be overhunted,” Robards said.
The study’s information points to wolverines’ need for undisturbed habitat and space as an important consideration for management decisions.
Habitat degradation and fragmentation led the U.S. Fish and Wildlife last year to classify the Lower 48 wolverine population as threatened.
And in Canada’s Yukon Territory, biologists discovered that patterns of hunting and trapping – with some places that are intensely harvested and others skipped over – have produced areas that are serving as de facto safe refuges for wolverines.
For the wolverines in Arctic Alaska, the development concern that is “front and center” has been the proposed Ambler Access Project, Robards said. It would punch an approximately 200-mile road from the Dalton Highway through the southern Brooks Range foothills to the isolated Ambler mining district in Arctic Northwest Alaska.
“The more you open up this environment, the more at risk those refuges are for people to overexploit, either through trapping or hunting,” he said.
Though wolverines are important to Indigenous residents of the North Slope, they have been somewhat neglected in academic and agency science, Robards said. “Our own sort of western perspective on this is they haven’t been a priority species to study,” he said.
That lower priority status shows up in some pre-development studies for projects in known wolverine territory.
In the Trump administration’s 2020 record of decision that approved oil leasing in the Arctic National Wildlife Refuge, the word “wolverine” appeared just once. The Bureau of Land Management’s 2019 environmental impact statement on which that decision was based also had scant mention of the species. Most of it was in an appendix that identified wolverine data as a knowledge gap.
The supplemental environmental impact statement for the Ambler road project released earlier this year by the Biden administration’s BLM does include wording considering how the road would affect wolverines, Glass said – something he knows because he submitted information.
A passage in one of the document’s four volumes discusses road impacts to wolverine habitat and wolverine movement patterns. That study and those that preceded it, however, focused much more attention on the road’s potential impacts to caribou.
The Biden administration in June rejected the Alaska Industrial Development and Export Authority’s plan to build the Ambler road.
In addition to presenting a new estimate for numbers and densities, the study by Glass and Robards sheds more light on wolverine behavior.
The animals are not as solitary as they are reputed to be, Glass said. The idea that they are unsocial, they said, is changing, and their tracking produced evidence backing that change of thought. Males and females were spotted together on camera, as were adults playing their young, he said. “It’s not too rare to see a group of wolverines traveling together, usually a family group out on the landscape,” he said.
Wolverines, which are members of the weasel family and not related to wolves or bears, are the subject of intrigue beyond Alaska’s borders.
In Canadian Innu culture, the wolverines are clever tricksters. The Canadian Space Agency named one of its moonrovers Kapvik, the Innu word for wolverine, an animal known to be “pint-sized but powerful,” according to the agency’s website.
