Changes in the Distribution of Stream-Dwelling Crayfishes in the Schoharie Creek System, Eastern New York State

Changes in the distribution of crayfishes in the Schoharie Creek drainage, eastern New York State, are assessed, based on historical records and surveys conducted in 1982-83 and 1996. The native crayfish assemblage in this region probably consisted of only three species: Cambarus bartonii, C. robustus, and Orconectes propinquus. In 1982-83, six crayfishes (C. bartonii, C. robustus, O. immunis, O. obscurus, O. propinquus, and O. rusticus) were collected in the drainage. In 1996, all the crayfishes except O. obscurus were found again, and an additional species (O. virilis) was captured at one site. Between the two survey periods, O. rusticus markedly expanded its range, while the range of O. propinquus decreased and the relative abundance of other species declined. The habitat use of each species is examined.