Multiscale Habitat‐Use Patterns For An Imperilled Crayfish, Faxonius wrighti

Faxonius wrighti , Hardin Crayfish, is an imperilled crayfish patchily distributed throughout five small tributaries entering the Tennessee River in southwestern Tennessee and northeastern Mississippi. Past field observations suggest that channelization and sedimentation contributed to its patchy distribution; however, this assumption has not been explicitly tested. We conducted 219 mesohabitat surveys across 22 stream reaches within the range of F. wrighti to characterize species–habitat patterns of F. wrighti presence at segment‐, reach‐ and mesohabitat‐scales. Raw detection was low across mesohabitat surveys, with F. wrighti only being detected at 30 of 219 mesohabitats (raw detection = 14%). Despite low detection, F. wrighti was observed in 10 reaches (naïve occurrence = 45%), with the highest rate in the Beason Creek tributary system with four occupied reaches. Several historic localities in three tributary systems yielded no detections, but a new locality was documented within Shiloh National Battlefield Park. At the segment scale, F. wrighti presence was positively associated with stream slope and soils that allow infiltration and reduce sediment delivery from runoff, and negatively associated with increased landscape disturbance. At the reach scale, presence was negatively associated with both silt depth and proportion of the reach covered by silt. At the mesohabitat scale, water depth, silt depth, and the presence of another stream‐dwelling crayfish, F. etnieri , were top predictors associated with F. wrighti presence. These findings support a link between F. wrighti presence and sediment‐related variables across spatial scales, confirming past anecdotal survey observations. Conservation actions aimed at reducing sedimentation and restoring channel complexity are likely to enhance the long‐term viability of F. wrighti and facilitate recolonization of historically occupied reaches.