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A Bayesian approach to conservation genetics of Blanding’s turtle (Emys blandingii) in Ontario, Canada

Davy, Christina M., Bernardo, Pedro H., Murphy, Robert W.
Conservation genetics 2014 v.15 no.2 pp. 319-330
endangered species, gene flow, genetic variation, population structure, species dispersal, turtles, Great Lakes, Ontario
Blanding’s turtle, Emys blandingii, is a globally endangered species with a range centred on the Great Lakes of North America. Several disjunct populations also occur along the East Coast of North America. Previous studies suggest that the Great Lakes portion of the species’ range exhibits panmixia. However, E. blandingii is restricted to relatively small populations in many areas around the Great Lakes. Therefore, panmixia across large geographic distances in this area is unlikely. Here, we apply Bayesian analyses of population structure to samples collected across southern Ontario (N = 97) to test a null hypothesis of panmixia and assess possible management units (MUs), and to estimate rates of gene flow across the study area. Sampled sites in Ontario represent a minimum of four distinct genetic clusters of E. blandingii, which we recommend should be considered as independent MUs. Preliminary evidence suggests that further structure may be present in less robustly sampled areas, which deserve further consideration. Genetic diversity at sampled sites is comparable to that reported for other freshwater turtles. Our comparison between this study and previous work confirms that genetic diversity in E. blandingii is reduced in disjunct eastern populations compared to populations centred on the Great Lakes. Genetic diversity in E. blandingii is not correlated with latitude, and instead may reflect post-glacial dispersal of this species from multiple Pleistocene glacial refugia.