The Ringed Crayfish, Orconectes neglectus neglectus, in Nebraska with a Revision of Its Distributional Range

摘要

Collections of crayfishes in Nebraska have yielded much new information on the distribution of the ringed crayfish, Orconectes neglectus neglectus. The distributional range of this species had been described as southwestern Missouri and northwestern Arkansas with extensions into Kansas and Oklahoma. Isolated, disjunct populations in northeastern Colorado, southwestern Nebraska, and northwestern and east-central Kansas were thought to be relict populations. Between 1995 and 2009, collections of crayfishes were made throughout Nebraska using various techniques including seining, trapping, dip-netting, and handgrabbing. To date, the ringed crayfish has been found in 56 streams in eight of Nebraska's 13 river basins. In the majority of Nebraska streams, they are found in clear, low-gradient, sand-bed streams where they utilize dense vegetative cover. In the Big Blue River basin, the streams are quite turbid and here they use rock riffles. The information collected during this work show that the previously known disjunct populations represent the edges of a much larger distribution centered in Nebraska. The data presented represents a significant revision of the range of distribution of this species.