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Springsnails are numerically dominant members of benthic communities in many springs of western North America and Australia. Several studies have shown the influence of water chemistry on their abundance and distribution within springs, but little information exists regarding their use of physical aspects of spring environments. Habitat preferences, niche breadth and overlap, and environmental factors influencing the structure of an assemblage of native springsnails (Pyrgulopsis avernalis, P. carinifera, and Tryonia clathrata) and the non-native red-rimmed melania (Melanoides turberculata) gastropod are described in a southern Nevada, USA, thermal spring province. Water temperature, current velocity, and substrate type were the most important physical factors structuring the assemblage. Springbrook wetted width, presence of armored and incised banks, and location of sample sites across the wetted width were also statistically significant, but less important factors. Each species occupied a wide diversity of habitats, but each species also exhibited habitat preferences for a range of depths, velocities, temperatures, or substrates. Niche overlap varied among species and habitats were partitioned among species for a minimum of two environmental resources. Competitive interactions appeared to minimally influence the structure and distributions of species belonging to this assemblage.

Findings suggest that springsnails are restricted to portions of a spring that provide suitable physicochemical conditions, and that each springsnail taxon may exhibit specific habitat requirements. Springsnail extinctions and declines in abundance in western North America and Australia can be attributed to human activities altering the discharge and water depth, substrate composition, current velocity, and water temperature of springs. Novel approaches are required to alter human uses and facilitate restoration, and protect the integrity of these unique and land aquatic systems.