Alpine species are among the plants and animals most threatened by climatic shifts because of their physiological and geographic constraints, said Erb. In 2010, the U.S. government denied endangered species listing for the American pika in part because there was insufficient data on its distribution and abundance across western North America. The American pika lives in mountainous regions including British Columbia, Washington, Oregon, Idaho, Montana, Utah, Wyoming, Colorado, Nevada, California and New Mexico.
Surprisingly, most of the pikas that have disappeared from Great Basin sites under study in recent years were from sites that experienced extremely cold temperatures and may be related to a lack of winter snowpack insulation, said Ray, who has participated in several Great Basin pika studies including the 2011 study. Ray suspects pikas may reduce summer foraging activities to avoid heat stress caused by rising temperatures, leading to smaller winter food caches that can't sustain them during extreme cold snaps.
Guralnick, also curator of invertebrate zoology for the University of Colorado Museum of Natural History, said pikas are becoming a "bellwether" species for mountain ecosystems, primarily due to their recent Great Basin declines. Prior to the new CU survey, population trends of pikas in the Rockies were relatively unknown, he said.
"Many have assumed that warming temperatures would be the primary signal affecting North American pikas," said Guralnick. "This study shows it is more complicated than that, and that drier conditions could affect the persistence of pikas across the West."
The CU-Boulder study team initially looked at about 800 historical records of pika sighti
|Contact: Liesl Erb|
University of Colorado at Boulder