Associated habitat and population characteristics of the Hiwassee headwater crayfish, Cambarus parrishi, in north Georgia

Cambarus parrishi is a rare, stream-dwelling crayfish endemic to the upper Hiwassee River watershed in northeastern Georgia and western North Carolina. A two year survey of C. parrishi at 22 sites across 4 streams was conducted to identify microhabitat associations and population characteristics, and represents the most comprehensive study of this species within Georgia. Field sampling expanded the range of C. parrishi to four separate streams in Georgia and resulted in the capture of 141 individuals. Generalized linear modeling of C. parrishi density demonstrated strong associations near stream banks with rough substrates composed of abundant cobbles and small boulders. Cambarus parrishi were reproductively active from September through October and reached sexual maturity earlier than indicated by historical data. Five possible age classes were defined with an unbalanced 1.7:1 (females:males) sex ratio. Cambarus parrishi exists mostly on federally-managed lands at high elevations. However, development activities that introduce fine substrates and eliminate heterogeneous habitats preferred by most stream-dwelling crayfishes could threaten this species. Although this study increased knowledge of the range of C. parrishi, additional data on population, habitat use, life history, and occurrences in other tributaries within the watershed are still needed.