When I first started walking in the alpine regions of the Sierra and Cascades, it was common to encounter the American pika, an adorable alpine cousin of the rabbit. You may recognize them unless you are confined to a large area of the Sierra Nevada north of Lake Tahoe where they have completely died out. As of yet, pikas have not been designated an ‘endangered species’ although there is grave concern about the level of decline in their population.
This edited story looks specifically at the population north of Tahoe but explains the vulnerability of the species to climate change.
Pikas are related to rabbits and live at high elevations in the mountains of North America. Climate change is shrinking the areas where they can live. With high metabolic rates and thick fur, pikas are well adapted to the cold temperatures at high elevations, but these same adaptations make them vulnerable to global warming.
Pikas spend the summer gathering grasses and wildflowers to store in "haypiles" for winter subsistence. When summer temperatures are too high, they are forced to stay underground.
The American pika, a small mammal adapted to high altitudes and cold temperatures, has died out from a 64-square-mile span of habitat in California’s northern Sierra Nevada mountains, and the cause appears to be climate change.
“The loss of pikas from this large area of otherwise suitable habitat echoes prehistoric range collapses that happened when temperatures increased after the last ice age,” said lead author Joseph Stewart, a Ph.D. candidate at UC Santa Cruz. “This time, however, we’re seeing the effects of climate change unfold on a scale of decades as opposed to millennia.”
Hikers and backpackers can still see pikas in the mountains surrounding the area of extinction. “Mount Rose and Desolation Wilderness are still great places to see pikas,” Stewart said. But not for long—the study forecasts that by 2050 climate change will cause a 97 percent decline in suitable climate conditions for pikas in the Lake Tahoe area.
Pikas spend their summers carrying mouthfuls of grass and wildflowers from mountain meadows to “haypiles” tucked away in the rocky habitat they call home.
“The classic image of a pika is one hopping from rock to rock with a little ‘bouquet’ of wildflowers in its mouth,” said coauthor David Wright, recently retired from the California Department of Fish and Wildlife.
Pikas don’t hibernate, but rather use their furnace-like metabolism and thick coat of fur to stay warm during winters under the snow. “A larger haypile acts as insurance policy against winter starvation,” explained Stewart. “But the same adaptations that allow them to stay warm during winter make them vulnerable to overheating in the summer, and when summer temperatures are too hot, they can’t gather enough food to survive and reproduce.”
The local pika extinction opens a large gap in the species distribution north of Lake Tahoe, and [researchers] believe this gap indicates the complete loss of population and genetic connectivity between pikas to the east and west.
The authors note that while management actions such as habitat protection, restoration, or assisted migration may be helpful for some climate-imperiled species, management options for the pika appear to be limited.
“Our hope is that simply getting the word out there that climate change is causing iconic wildlife to disappear will get people talking and contribute toward political will to reign in and reverse climate change,” Stewart said. “There’s still time to prevent the worst impacts of climate change. We need our leaders to take bold action now.”
