BOISE, Idaho — Researcher Erik Beever has watched the effects of climate change play out in front of his eyes.
The U.S. Geological Survey research biologist from Bozeman, Mont., studies American pikas, which are disappearing from the Great Basin that stretches from Idaho to California and where Beever and other researchers found them just a decade ago.
A new study published in the journal Ecology says less winter snowpack and summer rain are the major factors in the small mammal’s disappearance, even where good habitat is available.
The size of pika populations did not correlate with the extent of habitat, in either the 1990s or 2000s, according to the researchers who visited sites where pikas have been recorded in surveys going back more than a century. In other words, precipitation is the deciding factor in the health of the American pika in the Great Basin, no matter how much good habitat is available.
“Precipitation appears to be important because it can influence the amount of food available for pikas in the summer, and an insulating snowpack can minimize exposure of pikas to extreme cold-stress,” Beever said.
The results suggested that climate change may be creating a new factor in the suitability of habitat.
Snowpacks have been declining since the 1930s across the West at the same time that temperatures have been rising, the U.S. Geological Survey said.
Most surprising to the researchers was that smaller pika populations didn’t necessarily put them at higher risk for extinction.
“We were surprised to find that sites with higher extinction risk in 1999 had larger populations in 2003 to 2008,” Beever said.
Most of the remaining habitat is in alpine areas, such as Idaho’s Sawtooths and other mountain ranges.