Abstract
Endemic species with narrow ranges are vulnerable to extirpation, and understanding their habitat needs is fundamental to effective management. The Etowah Bridled Darter, Percina freemanorum , is a recently described fish species endemic to the Upper Etowah River in Georgia. Little is known about how its habitat requirements differ from its sister taxon, P. kusha, with which it was previously synonymous . Our objectives were to quantify the effects of watershed characteristics on P. freemanorum ’s distribution on the landscape and to characterize its microhabitat use and selection using snorkel surveys. We created a random forest species distribution model to assess watershed characteristics using a long-term occurrence database. We snorkeled 19 sites in the Upper Etowah River basin with previously known occurrences, recording microhabitat use and availability. The species distribution model indicated that P. freemanorum presence was negatively associated with historical agriculture, historical urbanization, and dams, and positively associated with 3rd–4th order streams between 400 and 500 m in elevation. In our snorkel surveys, we found that P. freemanorum used all available substrate types, depths between 15 and 100 cm, velocities between − 0.03 m/s and 0.83 m/s, and areas with and without wood, but disproportionately selected depths of 45–75 cm, velocities of 0.25–0.50 m/s, and sand, cobble, and bedrock substrates. Our results support previous assumptions that the species uses habitats with moderate velocity, shallow depths, and sandy substrates, but expands upon our previous understanding of the species’ preferences for certain microhabitats when available. Assessing habitat requirements at multiple scales provides essential information for guiding species conservation and management.