Alabama Strategic Habitat Units (SHUs) and Strategic River Reach Units (SRRUs)

These layers represent Strategic Habitat Units (SHUs) and Strategic River Reach Units (SRRUs) for federally listed and state imperiled species on GSA Special Map 248, "Strategic Habitat and River Reach Units for Aquatic Species of Conservation Concern in Alabama".   The U.S. Fish and Wildlife Service in conjunction with the Alabama Department of Conservation and Natural Resources and the Geological Survey of Alabama have selected watersheds and river segments in the five major HUC 4 subregions in Alabama to focus conservation activities for managing, recovering, and restoring populations of rare fishes, mussels, snails, and crayfishes. These Strategic Habitat Units (SHUs) and Strategic River Reach Units (SRRUs) include a substantial part of Alabama’s remaining high-quality water courses and reflect the variety of aquatic habitats occupied by these species historically and presently. The SHUs were selected based on the presence of federally listed and state imperiled species, potential threats to the species, designation of critical habitat, and the best available information about the essential habitat components required by these aquatic species to survive. This includes areas with: (1) geomorphically stable stream and river channels; (2) stream flow regimes that support normal behavior, growth, and survival of theanimals; (3)acceptable water-quality conditions necessary for normal behavior, growth, and viability of all life stages of the animals; (4) a diversity of channel substrate types, with minimal amounts of fine sediment and filamentous algae; (5) for mussels, the presence of fish hosts with adequate living, foraging, and spawning areas; and (6) few or no competitive or predaceous nonnative species. All of the SHUs currently support one or multiple federally and(or) state protected species and(or) critical habitat(s), as designated by the U.S. Fish and Wildlife Service.