Anthropogenic refugia ameliorate the severe climate-related decline of a montane mammal along its trailing edge

Abstract

We conducted detailed resurveys of a montane mammal, Urocitellus beldingi , to examine the effects of climate change on persistence along the trailing edge of its range. Of 74 California sites where U. beldingi were historically recorded (1902–1966), 42 per cent were extirpated, with no evidence for colonization of previously unoccupied sites. Increases in both precipitation and temperature predicted site extirpations, potentially owing to snowcover loss. Surprisingly, human land-use change buffered climate change impacts, leading to increased persistence and abundance. Excluding human-modified sites, U. beldingi has shown an upslope range retraction of 255 m. Generalized additive models of past distribution were predictive of modern range contractions (AUC = 0.76) and projected extreme reductions (52% and 99%, respectively) of U. beldingi's southwestern range to 2080 climates (Hadley and CCCMA A2). Our study suggests the strong impacts of climate change on montane species at their trailing edge and how anthropogenic refugia may mitigate these effects.