HYDROLOGY, HABITAT, AND HUMANS--CREATING RISK ASSESSMENTS FOR ALABAMA’S ENDANGERED URBAN FISH

Aquatic species face imperilment and are experiencing rapid rates of extinction at a disproportionate rate compared to terrestrial organisms. For aquatic organisms, diverse and dynamic hydrogeological processes as well as anthropogenic stressors can influence the suitability of local habitats over short and long timescales, often restricting species distributions. Connecting hydrogeological processes to local habitat requirements and understanding the impacts of natural and human-induced disturbance on those systems is paramount to creating effective conservation plans for imperiled aquatic species. The Black Warrior River system in Alabama is home to three federally listed species of fish, Watercress Darter (Etheostoma nuchale), Vermilion Darter (Etheostoma chermocki), and Rush Darter (Etheostoma phytophilum), that rely on groundwater-surface water interactions to complete life history requirements. Year-round groundwater inputs from springs and other baseflow sources provide habitat stability by buffering changes in surface water temperatures, yet spring locations restrict these species to areas that have long been subjected to development pressures and industrial perturbations. Potential changes to the natural hydrologic system from climate change may also compromise species survival. More intense and more frequent precipitation events could result in increased runoff and reduced aquifer recharge, potentially altering the groundwater-surface water system, leading to habitat modification or loss in spring habitats that rely on constant and consistent groundwater inputs. Ongoing monitoring efforts by the Geological Survey of Alabama focus on the physical variables that affect this conjunctive system as well as species distributions and habitat characteristics in the face of drought, flooding, and population growth to inform species conservation efforts. Habitat assessments and geospatial analyses increase our understanding of the effect of hydrology on habitat suitability and aid in creating risk assessments that incorporate multiple anthropogenic stressors and natural system controls. This multidisciplinary approach will help protect and enhance these fragmented habitats and better inform species recovery plans.