Stoneflies (Plecoptera) of the Black Hills of South Dakota and Wyoming, USA: Distribution and zoogeographic affinities

The Black Hills of South Dakota and Wyoming are an insular mountain range c ompletely surrounded by the Great Plains. The stonefly (Plecoptera) fauna o f the Black Hills was surveyed and zoogeographic affinities examined. Twent y-seven species representing 22 genera and 6 families were found. Fifteen n ew state records for South Dakota and 2 for Wyoming are presented. Two spec ies are removed from the South Dakota list. An analysis of the North Americ an distribution of each species showed a strong relationship between the Bl ack Hills and the Pocky Mountains, with much weaker relationships between t he Black Hills and eastern and northern regions. Results of a logistic regr ession analysis comparing factors contributing to long-distance dispersal a bility against presence/absence in the Black Hills were inconclusive. Howev er, other evidence suggests that the Black Hills fauna is a result of expan sion and subsequent vicariance of stonefly populations during Pleistocene c limatic oscillations.