Rising Temperatures and the Extirpation of Pika in California

by Kyle Jensen

The American pika, a cousin of rabbits and hares found in the mountains of western North America, may serve as a model organism for examining the effects of global warming on montane species. Pikas tend to live on talus slopes at higher elevations, and as their lower elevation limits are relatively high they may be especially vulnerable to climate change. Having adapted to colder climates pika are susceptible to hyperthermia in the summer, with a lethal upper body temperature occurring at only 3°C above their resting body temperature. During times of high temperature pikas reduce their foraging time to keep their body temperatures low, which also reduces their energy intake. Prolonged periods of high temperature can lead to reduced reproduction and death. Summer temperatures can thus place serious limits on the pika’s distribution. Stewart et al (2015) created a model to assess the potential risk posed to piks and other climate-sensitive mammals by climate change. Their model matched previous findings and predicted high levels of extirpation of pikas in study sites across California, with the size of talus area and summer temperatures being the best predictors of range. Continue reading