Goats and Glaciers

The second part of the narrative about F3 will be forthcoming, but in the meantime here are a couple of articles peripherally related to wolverine habitat and, possibly, diet.

Glacier National Park has lost two more of its namesake features, leaving it with just 25 glaciers, a paltry remnant of the 150 or so that were there when the park was formed . The remaining glaciers are predicted to melt within the next decade. Glacier Park is the heart of the Lower 48’s wolverine population; if the Rockies south of Glacier are considered an archipelago of high altitude islands between which wolverines must ‘swim’ to maintain a healthy population, Glacier itself is a mainland of sorts, with its own robust population that may (or may not?) send out dispersers to help maintain the population to the south. The Glacier wolverine study captured an animal, on average, every 11 trap nights. By comparison, the Absaroka-Beartooth Project has a capture rate of something like one animal every 45 traps nights (that number is not precise) with equivalent coverage of known occupied wolverine habitat. Wolverine home ranges are smaller in Glacier, perhaps indicating a greater concentration of food resources. On the whole, for a wolverine in the Lower 48, Glacier is probably the place to be. Given the links between successful wolverine denning and deep spring snowpack (Copeland et al, 2010), not to mention the role that the glaciers play in engineering a high altitude ecosystem, the loss of these features – or, more accurately, the climate trends that they illustrate – will have some implications for wolverines in what has been a stronghold of the population.

Mountain goats are another iconic species of Glacier National Park, but biologists don’t believe that these animals were present in the Greater Yellowstone region until they were introduced to parts of southern Montana by sportsmen in the 20th century. Reports that mountain goats are now making their way into Grand Teton National Park are presenting a problem for park managers, since the goats are invasive and may threaten the Tetons’ struggling bighorn sheep herd. On the other hand, who wants to be caught killing off cute, picturesque, and charismatic large ungulates in the name of cold-hearted scientific management? This kind of thing does not sit well with the public, even though it could be necessary to protect another population of cute, picturesque, and charismatic large ungulates.

Wolverines might be just as happy at the new arrivals as camera-wielding tourists, since mountain goats are an important food source in much of wolverine range. The Teton wolverines appear to be doing well even sans goats, but an influx of large, edible animals specially adapted to hang out on high craggy peaks where nothing else can comfortably live wouldn’t be a bad thing. Unless it interferes with the sheep, which wolverines might also be eating.

Wolverines can survive without mountain goats, so the presence of wolverines shouldn’t be taken as an argument against controlling the goats. But goats seem to be among gulo’s favored foods, so it’s simply an interesting ecological situation.


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