The Royle's pika is sensitive to high temperatures (>15☌) that lead to thermal stress and limit overall activity (Bhattacharyya, Adhikari, & Rawat, 2014b). Furthermore, the interannual variation in population density of the Royle's pika is often influenced by snow melting pattern, food availability, and refuge from predation risk (rock cover) (Bhattacharyya et al., 2014a). The Royle's pika usually occurs at low population densities from 12.5 per ha in Nepal to 16.2 per ha in the western Himalaya in India (Bhattacharyya, Adhikari, & Rawat, 2014a). It is an asocial mammal (Bhattacharyya & Smith, 2018, Figure 1) and, unlike other talus-dwelling pika species (e.g., American pika Ochotona princeps, Collared pika Ochotona collaris), does not exhibit haying activity to store winter food resources (Bhattacharyya, Adhikari, & Rawat, 2013). The Royle's pika ( Ochotona roylei) is a widespread small herbivore, occupying much of the Himalayan arc-from northwestern Pakistan to India (Jammu and Kashmir, Himachal Pradesh, and Uttarakhand), Nepal, and adjacent Tibet (Bhattacharyya & Smith, 2018) and inhabits rocky boulder or talus habitat between 2,400 and 5,200 m elevation. While dispersal to higher elevation may allow pikas to persist in suitable microclimate, habitat fragmentation or non-availability of preferred food plants can impair their ability to cope with the changing environment and pose a threat to their survival and fitness (Bhattacharyya, Dawson, Hipperson, & Ishtiaq, 2018 Ray, Beever, & Loarie, 2012 Schloss, Nuñez, & Lawler, 2012 Walther et al., 2002). For example, climate-induced heat (Beever, Brussard, & Berger, 2003), cold, or nutritional stress (Wilkening, Ray, Beever, & Brussard, 2011) led to historical extinctions of local populations and recent range contraction. Among mountain-dwelling species, pikas ( Ochotona species), in particular, have experienced a significant contraction in their lower elevation range (Moritz et al. Over the past century, climate has been changing at a faster pace in alpine habitats than in other ecosystems, for which many species must either adapt or migrate to areas with optimal conditions (Naftz et al., 2002 Shrestha, Gautam, & Bawa, 2012). This is the first population genetics study on Royle's pika, which helps to address evolutionary consequences of climate change which are expected to significantly affect the distribution and population dynamics in this talus-dwelling species. Our results reveal significant evidence of isolation by distance in genetic differentiation ( F ST range = 0.04–0.19). We have found evidence of a recent population bottleneck, possibly due to effects of environmental disturbances (e.g., snow melting patterns or thermal stress).
PIKKA WINDOWS 8 KEYGEN
Pika showed low inbreeding coefficients ( F IS) and a high level of pairwise relatedness for individuals within 1 km suggesting low dispersal abilities of talus-dwelling pikas. The detected genetic structure could be primarily attributed to the landscape features in alpine habitat (e.g., wide lowland valleys, rivers) that may act as semipermeable barriers to gene flow and distribution of food plants, which are key determinants in spatial distribution of herbivores. Using four clustering approaches, we found the presence of significant contemporary genetic structure in Royle's pika populations. In this study, we used seven polymorphic microsatellite loci to detect evidence for recent changes in genetic diversity and population structure in Royle's pika across five locations sampled between 8 and 160 km apart in the western Himalaya. This is particularly important for Royle's pika (Lagomorpha: Ochotona roylei), a herbivorous talus-dwelling species in alpine ecosystem, which forms a major prey base for many carnivores in the Himalayan arc. Herbivore responses to the environment can have a strong indirect cascading effect on community structure.
Understanding population genetic structure of climate-sensitive herbivore species is important as it provides useful insights on how shifts in environmental conditions can alter their distribution and abundance.
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