Are American Pikas (Ochotona princeps) in the Canadian Rockies Vulnerable to Climate Change?

摘要

The American Pika (Ochotona princeps) is vulnerable to climate change as a result of its dependence on cool, moist conditions. Most research on climatic determinants of American Pika distribution has been done in the United States where conditions are different from those in the higher-latitude pika ranges of the Canadian Rockies. I examined recent (1980-2009) and future (2050s and 2080s) average and maximum mean summer temperatures for 114 current American Pika locations in Alberta to assess whether future conditions are likely to place these animals at risk. At all current sites, mean summer temperatures (MSTs) in the 2050s are expected to be below that chosen by the United States Fish and Wildlife Service as a threshold for at-risk status of O. princeps. By the 2050s, most current American Pika locations have sufficient elevation within 5 km to allow individuals to migrate vertically to reach habitat with MST similar to that of their current location. Even in the 2080s,almost all current sites have sufficient elevation within 5 km to maintain extreme single-year and average MSTs lower than the highest values recorded at those sites in the recent past （13.9℃ and 12.5℃ respectively）. However， by the 2080s under an extreme greenhouse gas emissions scenario, only 34% of current pika sites will allow for such migration. Although considerable uncertainty remains, particularly with respect to availability of habitat, these results suggest that American Pika populations in Alberta will likely be capable of persisting throughout this century, although their survival will depend increasingly on successful vertical migration.