Chilton, J., A.E. Rosenberger, and R.J. DiStefano. 2020. Habitat associations and distributions of two endemic crayfishes, Cambarus (Erebicambarus) maculatus (Hobbs & Pflieger, 1988) and Faxonius (Billecambarus) harrisonii (Faxon, 1884) (Decapoda: Astacoidea: Cambaridae), in the Meramec River drainage, Missouri, USA. Journal of Crustacean Biology. https://doi.org/10.1093/jcbiol/ruaa033
Understanding the habitat associations and distributions of rare species is important to inform management and policy decisions. Cambarus (Erebicambarus) maculatus (Freckled Crayfish; Hobbs & Pflieger, 1988) and Faxonius (Billecambarus) harrisonii (Belted Crayfish; Faxon, 1884) are two of Missouri’s narrowly endemic crayfish species. Their distributional overlap offers an opportunity for multi-species research to address gaps in information required for conservation. Both species are listed as Vulnerable (S3) on Missouri’s Species and Communities of Conservation Concern Checklist due to their limited range within the Meramec River drainage (MRD) and the impact of anthropogenic activities therein. During the summers of 2017 and 2018, we sampled 140 sites throughout the MRD for crayfishes and associated habitat variables, which we related to crayfish presence in an occupancy modeling framework. We found C. maculatus occupancy was associated with larger stream orders, boulder substrate, dolomite geology, aquatic vegetation beds, dissolved oxygen, and pool mesohabitat. Faxonius harrisonii occupancy increased with boulder substrate, aquatic vegetation beds, the presence of C. maculatus, and decreased in 3rd order streams. We also expanded the known range for both species within the MRD. This study represents the opportunity for simultaneous assessment of multiple species with overlapping distributions to inform future management and policy decisions regarding them.