A multilocus evaluation of ermine (Mustela erminea) across the Holarctic, testing hypotheses of Pleistocene diversification in response to climate change

Abstract

Aim We examined data for ermine (Mustela erminea) to test two sets of diversification hypotheses concerning the number and location of late Pleistocene refugia, the timing and mode of diversification, and the evolutionary influence of insularization.Location Temperate and sub-Arctic Northern Hemisphere. MethodsWe used up to two mitochondrial and four nuclear loci from 237 specimens for statistical phylogeographical and demographic analyses. Coalescent species-tree estimation used a Bayesian approach for clade divergence based on external mutation rate calibrations. Approximate Bayesian methods were used to assess population size, timing of divergence and gene flow.Results Limited structure coupled with evidence of population growth across broad regions, including previously ice-covered areas, indicated expansion from multiple centres of differentiation, but high endemism along the North Pacific coast (NPC). A bifurcating model of diversification with recent growth spanning three glacial cycles best explained the empirical data.Main conclusions A newly identified clade in North America indicated a fourth refugial area for ermine. The shallow coalescence of all extant ermine reflects a recent history of diversification overlying a deeper fossil record. Postglacial colonization has led to potential contact zones for multiple lineages in north-western North America. A model of diversification of ermine accompanied by recent gene flow was marginally less well supported than a model of divergence of major clades in response to the most recent glacial cycles.

The Beringian Coevolution Project: holistic collections of mammals and associated parasites reveal novel perspectives on evolutionary and environmental change in the North

“…Conversely, some species that show deep phylogeographic structure in northwestern North America occur naturally on the western islands of the Alexander Archipelago (e.g., Dawson et al 2014). Some of these distinctive lineages of mammals and associated parasites represent paleoendemics, meaning that their DNA signatures reflect long-term persistence and divergence in glacial refugia along the North Pacific Coast (Koehler et al 2009a;Hoberg et al 2012b;Sawyer and Cook 2016), and these signatures are consistent with the Coastal Refugium Hypothesis.…”

“…Phylogeographic analyses based on broad BCP sampling are revealing concordant zones of genetic differentiation (Fig. 5) that help interpret the impact of the boundaries of the Beringian refugium, such as the Upper Kolyma region of Siberia in the west (e.g., Galbreath and Cook 2004;Kohli et al 2015;Haukisalmi et al 2016) and near the YukonAlaska border in the east (Dawson et al 2014). In addition, the influence of smaller peripheral refugia in the Canadian Arctic (Fedorov and Stenseth 2002;Fedorov et al 2003;Cook et al 2016b), southeast Alaska Sawyer and Cook 2016), and in the periglacial zone south of the Laurentide and Cordilleran ice sheets ) is being explored.…”

“…1), depending on region being sampled and on particular collaborative projects with natural resource agencies and commercial trappers. Within most of the mammalian species examined using molecular genetic analyses, substantial phylogeographic structure and cryptic species have been identified (e.g., Dawson et al 2014;Sawyer and Cook 2016).…”

“…Another mustelid example from high latitudes hinges on a series of studies of ermine across the Holarctic that revealed four independent phylogenetic lineages with disparate demographic and evolutionary histories (Fleming and Cook 2002;Dawson et al 2014;Colella et al, unpublished data). Two ermine lineages are widely distributed across the Arctic and meet in south coastal Alaska.…”

Ways to be different: foraging adaptations that facilitate higher intake rates in a northerly-wintering shorebird compared to a low-latitude conspecific

“…The rock sandpiper is among several polymorphic Beringian endemic species (e.g. Abbott and Brochmann, 2003;Cook et al, 2005;Dawson et al, 2014;Pruett and Winker, 2005) whose polymorphy has been shaped by rapid, dynamic geologic processes throughout the region (Hopkins, 1959(Hopkins, , 1973. The final formation of Cook Inlet as a geographic feature is believed to have occurred ∼14,000 years ago (Reger et al, 2007;Schmoll et al, 1999) and fossil evidence indicates immediate colonization of the region thereafter by Macoma (Schmoll et al, 1972).…”