Deep barriers, shallow divergences: reduced phylogeographical structure in the collared pika (Mammalia:Lagomorpha:Ochotona collaris)

Abstract

Aim Pikas (Ochotona spp.) are alpine specialists that show considerable morphological and genetic variation structured along latitudinal and elevational gradients. Recent studies of North American and Asian pikas have uncovered phylogeographical partitioning among separate mountain ranges and drainages, driven by Quaternary climate fluctuations. We tested the prediction that collared pikas (O. collaris) exhibit lower genetic diversity and less structure than other species of pika due to lower long‐term habitat stability. Location Eastern Beringia (Alaska and north‐western Canada). Methods We examined phylogeographical variation in the collared pika (O. collaris) throughout much of its known range using the mitochondrial cytochrome b gene. Population divergence and genetic diversity were compared within and between mountain ranges. Genetic diversity was contrasted with current and Pleistocene habitat fragmentation inferred from ecological niche models. Results Low but significant differentiation was evident between most populations of O. collaris, with little haplotype sharing among populations and a single phylogeographical break separating a genetically distinct haplogroup in the south‐eastern part of its range. Variation was mostly structured within populations (as opposed to between populations or mountain ranges). When within‐species nucleotide diversity in O. collaris, O. princeps and O. curzoniae was compared, genetic diversity was found to decline with increasing latitude. Main conclusions Populations of O. collaris are less geographically structured and exhibit less variability than populations of either O. princeps or O. curzoniae. This pattern is better explained by the amount of available Pleistocene habitat predicted for each species than by current predicted habitat or population discontinuity. Collared pikas are currently considered to be a common species at low risk of extinction, but their habitat specificity, population subdivision, and low genetic variation may have consequences for their continued viability in a warming world.

Genetic structure and differentiation of four populations of Afghan Pika (Ochotona rufescens) in Iran based on mitochondrial cytochrome b gene

“…It seems that there is not a major discontinuity between populations of Afghan Pika based on cyt-b mitochondrial gene. This result is in agreement with those of populations of collared Pikas that are less geographically structured and their haplotypes more closely related to one another (Lanier & Olson, 2012).…”

“…The result of Fu's F s analysis for the Salouk population is in agreement with negative and significant value of Fu's F s , high haplotype and low nucleotide diversity in four populations of the rare species Ochotona koslowi in a small area of eastern China (Lin, Ci, Thirgood, Zhang, & Su, 2010). The two other species of Pikas, Ochotona collaris (Lanier & Olson, 2012) and Ochotona curzoniae (Ci et al, 2009), showed the same result of expansion based on negative value of Fu's F s test, high haplotype diversity and low nucleotide diversity in most of the populations.…”

“…The nucleotide diversity (0.28 %) was less than that performed with the same locus for O. koslowi (0.53 %) (Lin et al, 2010), O. collaris (0.7 %) (Lanier & Olson, 2012) and O. curzoniae (2.6 %) (Ci et al, 2009;Yu et al, 2012) Intraspecific genetic variation is related to historic and current evolutionary processes (Avise et al, 1987). Current gene flow could be a main evolutionary process for shaping variation when there is a strong relationship between genetic and geographic distance, especially in species with low dispersal ability (Miller, 1997;Peterson & Denno, 1998;Darling, Reitzel, & Finnerty, 2004).…”

Colonization from divergent ancestors: glaciation signatures on contemporary patterns of genomic variation in Collared Pikas (Ochotona collaris)

“…Samples of 58 Collared Pikas from nine populations were collected, and their DNA was extracted as described previously (Lanier & Olson ; Table S1, Supporting information). Localities were chosen to broadly represent the species' range (Fig.…”

“…Studies of historical biogeography of Collared Pikas have concluded that population differentiation has been in part driven by Pleistocene population distributions (Lanier & Olson ). Two mitochondrial lineages are present, corresponding to inferred western (Beringian) and eastern Pleistocene refugia (Lanier & Olson ). Studies of mountain goats (Shafer et al .…”