Thursday, August 9, 2007 - 10:30 AM

COS 102-8: Inferring the role of climate change in the accelerating decline of the American pika (Ochotona princeps)

Erik A. Beever, NPS Great Lakes Network and Chris Ray, University of Colorado-Boulder.

We report new evidence that the local extinction rate for American pikas in the Great Basin has continued to accelerate over the past decade, and new analyses inferring the role of climate change in these extinctions.  Existing populations are also ‘moving uphill’ at an accelerating rate that now far outpaces other elevational range-shifts reported in the literature.  We estimate that the minimum elevation occupied by populations persisting in the Great Basin has risen more than 100 m over the past decade, representing over 70% of the uphill movement evidenced during the past century.  Given the remote locations occupied by this species, there are a limited number of stressors hypothesized to affect such dramatic changes in its distribution.  Climate change, in the form of higher summer temperatures, is one stressor that had been implicated in a previous model-selection analysis.  We confronted several of the best models from this previous analysis with our new data on local extinctions.  This process of model updating has confirmed the support for climate change as a predictor of local extinctions, and provides a basis for tracking temporal changes in the relative importance of climate as a predictor.