Credit: ©iStockphoto/Jeff Goulden

Recent climate change in the American West has substantially increased the rate of local extinctions of one small, mountain-dwelling mammal and has spurred surviving populations to move to cooler spots upslope, a study suggests.

Erik Beever, an ecologist formerly at the University of Nevada, Reno, and colleagues compared the modern and historical ranges of the American pika within a 38-million-hectare area centred on Nevada1. Surveys taken between 1994 and 1999 revealed that pikas were missing from six of the 25 study sites where they had been recorded from 1898 to 1956. But tallies taken at the same sites between 2003 and 2008 revealed another four extirpations, generating a nearly five-fold jump in local extinction rate.

The most recent surveys revealed that the low-altitude edge of the pikas' range had moved upslope about 145 metres since the 1990s, about 11 times the rate of retreat seen during the twentieth century. Because pikas don't migrate and are generally faithful to their locale, the researchers speculate that rising temperatures have driven the heat-sensitive creatures from many sites they formerly inhabited.