Pikas, Gulos, and Climate Change

A small but notable mention of wolverines appears in an article about climate change impacts on North American pikas. These small, talus-dwelling, temperature-sensitive members of the rabbit family are dying out of colony sites where temperatures rise above 24º C in the summer, and where decreasing snowpack leaves them less insulated in the winter. In the past decade, pikas in the Great Basin have migrated uphill an average 475 ft, compared to an average of 40 ft per decade through the 20th century. In the same alarming vein, pika colonies blinked out every 10.7 years, on average, throughout the 20th century; in the past eleven years, colonies have been going extinct every 2.2 years. These trends appear to extend beyond the Great Basin, encompassing the rest of the Rockies as well.

How does this relate to wolverines? Anecdotes suggest that gulos sometimes prey on pikas, so the loss of a food source is an issue. But more importantly, pikas and wolverines share habitat, and the same things that limit pikas – temperature and snowpack – also limit wolverines. Pikas are easy to study; there are a lot of them, and they have tiny little legs, so they can’t go very far. Keeping track of them is easy. Wolverines, on the other hand, are rare, and move constantly and quickly, so keeping track of them – and figuring out what is going on at a population level – is much more complicated. (Pika biologist Erik Beever, whose research is the subject of the article above, implied at a March 2010 pika conference that people who want to study wolverines are the masochists of the wildlife biology world, neatly summarizing the issue by pointing out that it takes only one individual to observe many pikas, but many individuals to observe a single wolverine. Which is probably true, but who wants life to be easy?) What happens to pikas is probably an indicator of the challenges that wolverines will face over time. Obviously it’s not a one-to-one substitution, but the parallels are clear.

I’m also interested in this mention of wolverines and pikas because our project in Mongolia includes a pika component, for precisely the reasons that Beever refers to in this article. Wolverines in the old and the new world are the same species; American pikas and Mongolian pikas are in the same genus, Ochotona, with two species in the US and four in Mongolia. Both of the North American species are talus-obligate, which means that they are found only in the mountains. Two of Mongolia’s pikas are burrowing species, living in the steppe. The remaining two are montane-dwelling, and one, the alpine pika (O. alpina) appears to be talus-obligate. We aren’t entirely sure, because scientists have done little research on Mongolia’s mountain pikas. Our fieldwork in Mongolia last year included surveys for alpine pikas in three of Mongolia’s mountain ranges, and we hope to set up longer-term monitoring sites to determine whether alpine pikas are responding to climate change in the same way that North American pikas are responding. We will use methodologies similar to those used in the US, generating a globally comparable dataset.

I haven’t dedicated nearly enough space to the topic of the broader context of the Mongolia project; this is, after all, The Wolverine Blog, not the Wolverine and Other Interesting Animals Blog. But as Erik Beever also pointed out at that same conference, ultimately it’s more efficient, from a conservation point of view, to care about all of the species in mountain ecosystems instead of intensively focusing efforts on only one. He is absolutely right. We need broad solutions for the entire suite of high altitude species, before it’s too late.

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