Arctic Wolverine Surveys

In April of this year two Supercubs glided to a landing in Umiat, a lonely outpost on the North Slope of Alaska. It was decidedly not spring this far north as evidenced by the frozen Colville River and the snow-covered tundra all around. From one of the planes emerged Audrey Magoun, a pioneering wolverine biologist and her husband, pilot/wildlife biologist Pat Valkenburg. From the other airplane, Mark Keech, also a pilot/wildlife biologist, and his wife, geologist Tina Laird, also unfolded themselves from the cramped space they had been occupying for 6 hours and stretched their legs. They’d been flying these small airplanes back and forth across the top of the continent for weeks, at least on those days when they weren’t grounded by low-lying fog banks and blizzards. They had stopped at Umiat to re-fuel the airplanes for another pass across vast white expanses where they hoped to find tracks of wolverines and other species inhabiting the Arctic Slope, an area stretching from the Brooks Range to the Arctic Ocean. Sponsored by the Wildlife Conservation Society’s Arctic Beringia program, they were conducting the most comprehensive survey of wolverines on the Arctic Slope that has ever been done, in order to make a baseline map of wolverine distribution at its current population level. On a map of the Arctic Slope of Alaska they overlaid a grid of hexagons across a 62,000 square-mile study area and flew from the center of one hexagon to another recording wolverines and their tracks as well as signs of other wildlife, including wolves, caribou, muskox, and moose.

IMG_0538_cropped_den flyover_2

A wolverine den can be seen off of the right wing of the airplane shadow. Keen eyesight and attention to detail are necessary to conduct aerial tracking surveys.

Because they are superbly adapted to snowy environments, wolverines in the lower 48 states are thought to be vulnerable to climate change. In Canada they are considered a species of special concern because of increasing industrial activity and human access to its remote habitats via new roads and more snowmobiles. Very little is known about the potential effect of climate change and human developments on wolverines in Alaska, but their dependence on snowdrifts for sheltering their young and caching food in the tundra habitats of the Arctic Slope suggests that climate change could be a factor in the future of wolverines in the region.

A wolverine on the North Slope of Alaska as seen from the Super Cub during aerial tracking surveys in April 2015.

A wolverine on the North Slope of Alaska as seen from the Super Cub during aerial tracking surveys in April 2015.

Wolverines are solitary animals, members of the weasel family, with relatively large ranges, with some male wolverines occupying 150 square miles or more. One of the iconic species found in arctic Alaska, the wolverines is virtually proof of a true northern wilderness area. As Audrey says, “if an area doesn’t have wolverines, I don’t feel like I’m in the northern wilderness.” The airplanes used the long days of the arctic spring to fly nearly 14,000 miles, recording tracks, dens, and the occasional animal. Audrey and the crew spent time in the remote villages of Umiat, Barrow, and Atqasuk waiting for blizzards to pass and talking to locals who report that this year is a particularly good year for wolverines. Anecdotal information like that tells us basic information, that numbers of wolverines fluctuate between years, though we don’t yet know what affects wolverine numbers and distribution. Local trappers capture wolverines to use for fur ruffs and trim on their winter parkas and to sell to others in the villages who do not trap. At this time, there is little information on the number of wolverines trapped on the Arctic Slope or whether trapping is influencing distribution or numbers of wolverines in the study area. The Wildlife Conservation Society has recently secured funding from the Murdock Foundation to study the relationship of wolverines to snow, particularly snowdrifts that linger into spring and summer, and to conduct genetic and toxicological studies on Arctic Slope wolverines. This new work will build on our understanding of wolverines in the lower 48 States, Alaska, and Canada and particularly on Audrey’s work on wolverines in northwest Alaska in the 1980s. Understanding such factors as importance of snowdrifts, presence of other species, trapping pressure, and the health, size, and structure of the wolverine population will help guide future development location and practices and help this species thrive in the changing arctic environment.

WCS wolverine surveys

Flight lines flown during wolverine surveys. The intensity of color indicates number of times flown.

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