New research, published in late August in the Journal of Mammalogy, tracks how pika populations have disappeared completely from areas where they had previously been found. The U.S. Geological Survey (USGS) researchers studied areas within the Great Basin, southern Utah, and northeastern California and identified climate variables and suitable habitat as being indicators of whether pika populations would persist. In the Great Basin, pikas were no longer found in five of the nine areas where pikas had historically been present. They were also absent in 11 of the 29 historical sites in northeastern California, and they were no longer found in any of the study sites where they had previously been found in Zion National Park and Cedar Breaks National Monument in southern Utah. In the Great Basin and southern Utah, temperature and precipitation were closely correlated with the presence of pika, but in northeastern California the limiting variable appeared to be suitable talus habitat.

?It is certainly clear that changes we have observed in pika distribution are primarily governed by climate, given that nearly all of our climate-related predictions have been borne out,? said Erik Beever, USGS research ecologist, and lead author of the study. ?However, we are still refining our understanding of the exact combination of direct and indirect pathways by which climate is bringing about change.?