PHENOTYPIC VARIATION IN REMNANT POPULATIONS OF NORTH-AMERICAN BISON

Eight external characters distinguishing plains bison (Bos bison bison) and wood bison (B. b. athabascae) were analyzed in six extant populations of plains bison and five populations of animals with ancestry of wood bison to test whether panmixis occurred in Wood Buffalo National Park following the introduction of plains bison and to test whether the variation is ecophenotypic. Character states were polarized from wood to plains bison and scored numerically. Frequencies of individual scores and indices were analyzed by a series of tests, and populations were ranked according to phenotype. Analysis of overall phenotypic variation based on all eight characters revealed three significantly different groups: plains bison; the subpopulation from Pine Lake; the other subpopulations from Wood Buffalo National Park. Results indicate that panmixis has not occurred since the 1925-1928 introduction of plains bison to the Park and that the characters studied are genetically based.