Contemporary genetic structure of the northern bobwhite west of the Mississippi River

We used mitochondrial DNA to study the population structure and genetic diversity of the northern bobwhite (Colinus virginianus) west of the Mississippi River. We observed a lack of phylogeographic structure, high haplotype diversity, and low nucleotide diversity for northern bobwhites in this part of their geographic range. Despite the discordance between geographic patterns of mtDNA diversity and subspecies designations, we detected significant genetic differentiation among 4 subspecies, the plains (C. v. taylori), eastern (C. v. virginianus), Texas (C. v. texanus), and masked (C. v. ridgwayi) bobwhites. Evidence of significant isolation by distance and a latitudinal gradient with regard to the geographic distribution of haplotypes was also apparent. Neutrality tests, Bayesian skyline plots, and test of spatial expansion provided evidence of demographic and range expansion following the end of the last Pleistocene glaciation. Lack of phylogeographic structure indicates that morphological differences that are the basis of subspecies designations are of recent origin. Ecoregions may provide a better basis for management units than subspecies taxonomy for northern bobwhites in the western part of their geographic range. Our results indicate that much of the northern bobwhite's geographic range in the United States is the result of relatively recent colonization, which was a response to climate and habitat changes at the close of the Pleistocene. The northern bobwhite may be as vulnerable to fluctuations in climate as it has been to habitat and landscape changes during the past century. (c) 2014 The Wildlife Society.