Background
Figure 1. Range of collared and American pikas.
Collared pikas are found in northwestern North America, primarily in mountainous areas in Alaska and the Yukon territory (Figure 1). They occur in small and isolated populations at high latitudes and elevations under environmental conditions that are extreme and highly changeable from year to year. Despite their ability to persist in these environments, there are concerns that pikas, with their restricted ranges and habitat requirements, will be particularly vulnerable to climate change (Bruggeman 2010; Beever et al 2010; Beever et al 2003).
While species at low elevations have been shown to move upslope as their ideal habitats shift (Moritz et al 2008), pikas live high in the mountains where there are few upslope alternatives. They are also considered unlikely disperse over long distances to adjacent alpine meadows (Smith 1974). In part, this is due to the challenges of translocating long distances and across elevations. Additionally, pikas are very sensitive to high ambient temperatures (MacArthur and Wang 1973) , which may prevent them from moving too far from areas where they can escape from the heat of the day.
While species at low elevations have been shown to move upslope as their ideal habitats shift (Moritz et al 2008), pikas live high in the mountains where there are few upslope alternatives. They are also considered unlikely disperse over long distances to adjacent alpine meadows (Smith 1974). In part, this is due to the challenges of translocating long distances and across elevations. Additionally, pikas are very sensitive to high ambient temperatures (MacArthur and Wang 1973) , which may prevent them from moving too far from areas where they can escape from the heat of the day.
Pika collecting haypile vegetation
Climate change may have positive as well as negative consequences for collared pikas. Longer growing seasons and earlier spring snowmelt are thought to provide pikas with additional time to gain good body condition and build a haypile that will sustain them over the winter (Morrison and Hik 2007). At the same time, it is feared that decreased snow accumulation will mean that the haypiles will not be adequately insulated and that pikas, who do not hibernate, will be more exposed to winter climate, including freezing rain called by increased winter temperatures (Morrison et al. 2009; Morrison and Hik 2007).
The quality of habitat is speculated to be another key factor in pika survival (Franken 2002). A talus patch may consist of several haypiles, with each haypile representing the territory of a single pika who will tend to use the site year after year (Smith 1978). Young of the year disperse from their natal territories shortly after weaning and must find and establish a territory and gather a haypile in the few short snow-free months in order to survive the winter (Franken and Hik 2004). Talus boulders provide shelter from heat and rain in summer, a place to nest in winter, and an escape from most predators. The location of a haypile needs to be close enough to vegetation to provide a source of food and the materials for haypile construction, while allowing the animal a quick escape if a predator appears (Morrison et al. 2004).
The quality of habitat is speculated to be another key factor in pika survival (Franken 2002). A talus patch may consist of several haypiles, with each haypile representing the territory of a single pika who will tend to use the site year after year (Smith 1978). Young of the year disperse from their natal territories shortly after weaning and must find and establish a territory and gather a haypile in the few short snow-free months in order to survive the winter (Franken and Hik 2004). Talus boulders provide shelter from heat and rain in summer, a place to nest in winter, and an escape from most predators. The location of a haypile needs to be close enough to vegetation to provide a source of food and the materials for haypile construction, while allowing the animal a quick escape if a predator appears (Morrison et al. 2004).
Collared pika
Pika populations have been declining throughout their ranges in North America. The Canadian Committee on the Status of Endangered Wildlife in Canada (COSEWIC) has recently identified the collared pika as one of its highest priorities for status assessment due to declining populations and vulnerability to warming winter temperatures(http://www.cosewic.gc.ca/eng/sct3/index_e.cfm).
