Genetic analysis of the black bear (Ursus americanus ) in Ontario.

摘要

Black bears have been adversely affected by human expansion and development through habitat loss and fragmentation. In order to investigate the genetic connectivity of the black bear across Ontario, 468 bears from eight localities were profiled at 15 microsatellite DNA loci. In addition, a novel gender determination method was performed on 183 bears and a sub-set profiled at the mitochondrial DNA control region (n = 88). Assignment of individuals into genetic clusters provided support for three groups of bears in Ontario. High levels of genetic variation and moderate levels of gene flow (H o = 0.74--0.75, FST = 0.02) were observed between two clusters located in central and northern Ontario. However, a third cluster associated with the Bruce Peninsula had low levels of variation and was genetically isolated (Ho = 0.54, FST = 0.14--0.15). Gene flow appears to be maintained by short distance dispersal of males. In addition, road density was significantly correlated to the observed level of genetic structuring. Fine scale analyses of bears sampled from the Bruce Peninsula revealed bears from another isolated population may have recently immigrated into the upper portion of the peninsula. As the human population continues to increase in Ontario, habitat fragmentation will likely reduce migration and decrease connectivity, leading to the isolation of additional populations. Management efforts should be concentrated on facilitating and maintaining connectivity especially among protected areas.