Population subdivision and peripheral isolation in American badgers (Taxidea taxus) and implications for conservation planning in Canada

In Canada, three subspecies of American badgers (Taxidea taxus (Schreber, 1777)) traditionally are identified; two of which are listed as endangered because of their restricted geographic range and low population sizes. To verify their subspecific designations and genetic insularity, we analyzed mitochondrial control region sequences within and among badger subspecies (Taxidea taxus jacksoni Schantz, 1946, Taxidea taxus jeffersonii (Harlan, 1825), and Taxidea taxus taxus (Schreber, 1777)) from nine locations in Canada and bordering United States. Although subspecies designations were supported (a priori subspecific designations, n = 3, AMOVA: FST = 0.40, p < 0.001), insular populations also were found within subspecific ranges as shown by spatial analysis of molecular variation, which suggested that our sample set consisted of five genetic groups (FST = 0.39, p < 0.001). These five distinct groupings included the subdivision of T. t. jeffersonii on either side of the Selkirk Mountains, and of T. t. jacksoni in the western part of its range grouping more closely with T. t. taxus of Manitoba. These results indicate that endangered populations of badgers may be more segregated than previously identified using morphological characteristics as proxies for subspecific designation. These results have important implications for the conservation of badgers in Canada, particularly of the two endangered subspecies.