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Klutsch C.F.C.,Trent University | Manseau M.,Northern and Western Service Center | Manseau M.,University of Manitoba | Wilson P.J.,Trent University
PLoS ONE | Year: 2012

Glacial refugia considerably shaped the phylogeographical structure of species and may influence intra-specific morphological, genetic, and adaptive differentiation. However, the impact of the Quaternary ice ages on the phylogeographical structure of North American temperate mammalian species is not well-studied. Here, we surveyed ~1600 individuals of the widely distributed woodland caribou (Rangifer tarandus caribou) using mtDNA control region sequences to investigate if glacial refugia contributed to the phylogeographical structure in this subspecies. Phylogenetic tree reconstruction, a median-joining network, and mismatch distributions supported postglacial expansions of woodland caribou from three glacial refugia dating back to 13544-22005 years. These three lineages consisted almost exclusively of woodland caribou mtDNA haplotypes, indicating that phylogeographical structure was mainly shaped by postglacial expansions. The putative centres of these lineages are geographically separated; indicating disconnected glacial refugia in the Rocky Mountains, east of the Mississippi, and the Appalachian Mountains. This is in congruence with the fossil record that caribou were distributed in these areas during the Pleistocene. Our results suggest that the last glacial maximum substantially shaped the phylogeographical structure of this large mammalian North American species that will be affected by climatic change. Therefore, the presented results will be essential for future conservation planning in woodland caribou. © 2012 Klütsch et al.

Petersen S.D.,Trent University | Petersen S.D.,University of Winnipeg | Petersen S.D.,Northern and Western Service Center | Petersen S.D.,University of Manitoba | And 8 more authors.
Journal of Mammalogy | Year: 2010

During his expeditions to the North Pole Robert Peary harvested at least 233 Peary caribou (Rangifer tarandus pearyi) from the northeast (NE) portion of Ellesmere Island, Nunavut, Canada. To assess the impact of this intensive local harvest we compared historic and contemporary samples. We explored 2 models of repopulation for this region. In the recovery model animals not hunted by Peary were the source of the current population. In the recolonization model animals from adjacent regions contributed to the current population. A genetic assessment of mitochondrial DNA (mtDNA) diversity comparing historic specimens (n = 12) to contemporary samples from the same region (n = 22) indicates the loss of 1 major mtDNA haplogroup. In this region historic and contemporary samples were significantly differentiated from one another. Combined mtDNA (n = 121) and 9 nuclear DNA loci (n = 151) indicate that the contemporary NE animals are most similar to those in adjacent regions to the south. We interpret this as supporting our recolonization model and suggest that, following Peary, animals dispersed north from central Ellesmere. Animals from the region to the west (NW) of NE showed the greatest differentiation from all other regions, suggesting that although proximate in distance, movement between the NW and NE might always have been limited. The NW region was unique in that it contained 1 predominant mtDNA haplotype at high frequency (0•88), the lowest observed heterozygosity (Ho = 0•50), and the highest mean relatedness (R = 0•063). Our combined results highlight the sensitivity of populations at the range limit to stochastic events and the potential limits to recovery following significant perturbations. © 2010 American Society of Mammalogists.

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