Fecal Pellets of American Pikas (Ochotona princeps) Provide a Crude Chronometer for Dating Patch Occupancy

Lyle B. Nichols
2011 Western North American Naturalist  
American pikas (Ochotona princeps Richardson) are small (130-g), diurnal alpine lagomorphs that inhabit talus patches in the mountains of western North America (Smith and Weston 1990) . Pikas are relatively easy to detect because they are diurnally active, highly vocal, and individually territorial, and because they leave behind obvious and distinctive sign, mainly hay piles and fecal pellets (Ray and Beever 2007, Beever et al. 2008, E.A. Beever personal communication). In addition, pikas have
more » ... combination of characteristics that may make them especially vulnerable to rapid climate change: intolerance to high ambient temperatures (MacArthur and Wang 1973, Smith 1974b), extreme specificity to talus, limited dispersal ability (Smith 1974a, Smith and Ivins 1983 ; but see Peacock 1997), and social intolerance (Smith and Ivins 1984). As such, pikas may be susceptible to local extirpation in the face of global warming (Beever 2002). Recent concern over pika adaptability to rapid climate change has led to research that examines ongoing changes in pika distribution in western North America (Beever 2002 , Beever et al. 2003 , Simpson 2009) . Because of their sensitivity to climate change (Morrison and Hik 2008), pikas may be an ideal indicator species to monitor the effects of climate change. Recently, a petition was filed to list pikas as threatened in the state of California, primarily because of deleterious impacts of global warming (Wolf et al. 2007 ). This petition was rejected, in part, for lack of evidence of range contractions in California (Carlson 2008) . In fact, few published studies describe recent changes of pika distributions in California (see Beever 2002 , Moritz et al. 2008 ). However, serious range contractions and local extirpations have been documented across Great Basin mountain ranges, immediately adjacent to the Sierra Nevada (Beever et al. 2003 . Great Basin pika distributions are known for the entire Holocene Epoch because fossilized pika remains and pellets found in woodrat middens and other paleontological and archaeological sites extend back to the late Wisconsinan Glacial Episode (Grayson 2005). Even so, incomplete historical information regarding location of pika populations limits biologists' ability to accurately track distributional changes. Recent pika distributions can be inferred from
doi:10.3398/064.070.0410 fatcat:bpfde2ofi5ehfkjjrqqwtqjxce