On the generality of a climate-mediated shift in the distribution of the American pika (Ochotona princeps)

Abstract

Abstract. Alpine species are among those most threatened by climatic shifts due to their physiological and geographic constraints. The American pika (Ochotona princeps), a small mammal found in mountainous, rocky habitats throughout much of western North America, has experienced recent population extirpations in the Great Basin linked to climatic drivers. It remains unclear whether these patterns of climate-related loss extend to other portions of the species' range. We investigated the distribution of the American pika and the climatic processes shaping this distribution within the Southern Rocky Mountain region. Results from a survey of 69 sites historically occupied by pikas indicate that only four populations have been extirpated within this region over the past few decades. Despite relatively few extirpations, low annual precipitation is implicated as a limiting factor for pika persistence in the Southern Rockies. Extirpations occurred only at sites that were consistently dry over the last century. While there was no climate change signal in our results, these data provide valuable insight into the potential future effects of climate change on O. princeps throughout its range.

Microrefuges and the occurrence of thermal specialists: implications for wildlife persistence amidst changing temperatures

“…Although some populations of pikas have experienced climate-related range contractions [35] and extirpations as a result of climate change [31,36,37], these patterns are not consistent across the species' range [38][39][40]. Whereas low-elevation populations in the southern Great Basin recently have shown significant upslope range retractions in response to warming temperatures [36,41], populations in the nearby eastern Sierra Nevada mountains persist despite marginal climatic conditions, atypical habitat and low-quality vegetation [42].…”

“…Haypiles are caches of vegetation that pikas harvest during the summer months and primarily consume when green vegetation is no longer available [56]. We did not classify plots as occupied based only on fresh scat because of challenges in confidently ageing scat [40,53] and the length of time that scat can persist in the environment [54]. Two observers conducted surveys at a subset of plots (n = 59) to estimate detection probabilities.…”

“…We recorded plot-level characteristics known to influence pika occurrence, including slope, aspect and elevation at each survey location [40,49,50,56]. Slope and aspect were measured at the center of each plot using a hand-held compass equipped with a clinometer.…”

Are American Pikas (<em>Ochotona princeps</em>) in the Canadian Rockies vulnerable to climate change?

“…Concerns over the effects of climate change on pikas arise from several sources including observations of population disappearance (Beever et al 2003(Beever et al , 2011stewart et al 2015), elevational retreat (Beever et al 2003(Beever et al , 2011Grayson 2005;Millar and Westfall 2010), susceptibility to acute (MacArthur and Wang 1974;smith 1974a) and chronic heat stress (Beever et al 2010;Wilkening et al 2011;stewart et al 2015), increasing frequency of low precipitation and snowpack (erb et al 2011;Beever et al 2013;Jeffress et al 2013), limited dispersal ability (seppänen et al 2012;Beever and smith 2013), restriction to areas of permafrost (hafner 1993, 1994Millar and Westfall 2010;Wilkening et al 2015), dependence on higher elevations (Rodhouse et al 2010), and habitat change (CoseWiC 2011).…”

“…Recent efforts to establish a climatic envelope have used extensive data sets and sophisticated statistical techniques (erb et al 2011;Calkins et al 2012;Ray et al 2012;Jeffress et al 2013;erb et al 2014;stewart et al 2015), but a clear understanding of the factors limiting pika distribution remains elusive. suggestions from one or more authors have included elevation, aspect, mean annual temperature, acute heat stress, acute cold stress, chronic heat stress, precipitation, and snowpack.…”