Genetic structure of North American wolverine (Gulo gulo) populations

Wolverines (Gulo gulo) are found in low densities throughout their circumpo lar distribution. They are also potentially susceptible to human-caused pop ulation fragmentation (development, recreation and fur harvesting). The com bination of these factors has contributed to this species being listed as h aving either vulnerable or endangered status across much of its current ran ge. The effects of inherently low densities and anthropogenic pressures on the genetic structure and variation of wolverine populations are, as yet, u nknown. In this study, 461 individuals were typed at 12 microsatellite loci to investigate the population genetic structure of wolverines from north-w estern Alaska to eastern Manitoba. Levels of gene flow and population diffe rentiation among the sampled regions were estimated via a genotype assignme nt test, pairwise F-ST, and two genetic distance measures. Our results sugg est that wolverine populations from southernmost regions, in which anthropo genic factors are strongest, revealed more genetic structuring than did nor thern populations. Furthermore, these results suggest that reductions in th is species' range may have led to population fragmentation in the extreme r eaches of its southern distribution. The continued reduction of suitable ha bitat for this species may lead to more populations becoming isolated remna nts of a larger distribution of northern wolverines, as documented in other North American carnivore species.