Shrinking range of pikas in California mountains linked to climate change

http://www.eurekalert.org/pub_releases/2015-02/uoc--sro020215.php

Public Release: 2-Feb-2015
University of California - Santa Cruz

The American pika, a small animal with a big personality that has long delighted hikers and backpackers, is disappearing from low-elevation sites in California mountains, and the cause appears to be climate change, according to a new study.

Researchers surveyed 67 locations with historical records of pikas and found that the animals have disappeared from ten of them (15 percent of the sites surveyed). Pika populations were most likely to go locally extinct at sites with high summer temperatures and low habitat area, said Joseph Stewart, a graduate student at UC Santa Cruz and first author of a paper reporting the new findings, published January 29 in the Journal of Biogeography.

"This same pattern of extinctions at sites with high summer temperatures has also been observed in the Great Basin region," Stewart said.

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Backpackers and hikers often see pikas scurrying back and forth across the rocks, gathering little bouquets of wildflowers in their mouths," Stewart said. "They are uniquely adapted to cold temperatures, but these same adaptations make the species vulnerable to global warming."

When summer temperatures are too high, pikas are forced to stay underground to avoid overheating. Less time spent foraging means they don't have as much food to eat, which increases the likelihood of local extinction.

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"It looks like we're going to lose pikas from many areas where people have been used to seeing them. It's a loss not just for the pikas but also for future generations who won't get to have that experience," Stewart said.

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Pikas and other high-elevation species can respond to warming temperatures by moving upslope to higher elevations. But in many locations the mountains just aren't high enough to provide a refuge from warming temperatures for high-elevation species. The study predicts that only the highest peaks of the southern Sierra Nevada, Mt. Shasta, and the White Mountains are likely to remain suitable for pikas through the end of the 21st century.