Abstract
The maritime shrew, Sorex maritimensis, is a Canadian endemic species with a limited distribution in two provinces in eastern Canada. Phylogeographic analysis of mitochondrial DNA control region and cytochrome b sequences revealed two clades, one found in New Brunswick and the other primarily in Nova Scotia, Canada. We propose that these clades have come back into secondary contact following the Wisconsin glaciation via wetlands on the narrow Isthmus of Chigneto that connects these provinces. Despite evidence of an historic separation of maritime shrew subpopulations in Nova Scotia and New Brunswick, we conclude that shrews in these two regions should be considered a single evolutionary significant unit but separate, semi-isolated management units that should be recognized as such for conservation purposes. The susceptibility of this stenotopic species with limited dispersal capabilities raises concerns about its long-term persistence if climate-change induced habitat fragmentation increases. Maintenance of contiguous wetland habitats is needed to ensure connectivity and gene flow among populations of the maritime shrew.
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Acknowledgements
We are grateful for in-kind support from Colin McKinnon of the Canadian Wildlife Service, Eric Tremblay of Kouchibouguac National Park, and Joe Kennedy of the New Brunswick Department of Natural Resources and Energy (Hampton). We also thank Margaret Wheaton and the many landowners for the use of their property. Julie Read, Patrick McCamphill, Owen Thompson, and Roxanne Struk provided great field and lab assistance and Sara Good-Avila offered helpful statistical advice. Funding for this project came from a Nova Scotia Museum Rare Species Grant, the Nova Scotia Habitat Conservation Fund, the New Brunswick Wildlife Trust Fund, and a National Sciences and Engineering Research Council of Canada Discovery Grant to DTS. KLD was supported by Acadia University Teaching Fellowships, the IUGB Wildlife Research Award, the Margaret McCarthy Research Scholarship, and the New Brunswick Museum Florence M. Christie Research Fellowship in Zoology.
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Dawe, K.L., Shafer, A.B.A., Herman, T.B. et al. Diffusion of nuclear and mitochondrial genes across a zone of secondary contact in the maritime shrew, Sorex maritimensis: implications for the conservation of a Canadian endemic mammal. Conserv Genet 10, 851–857 (2009). https://doi.org/10.1007/s10592-008-9645-7
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DOI: https://doi.org/10.1007/s10592-008-9645-7