Population monitoring of Illinois’ state endangered enigmatic cavesnail (Hydrobiidae) [presentation]

The Enigmatic Cavesnail, Fontigens antroecetes Hubricht (Gastropoda: Hydrobiidae) is known from only a single site in Illinois, Stemler Cave (St. Clair County). Other populations current identified as belonging to this species occur in Missouri. We initiated population monitoring in September 2009, and this monitoring continues through the present. We present findings thus far on snail densities and substrate preferences as determined by our sampling. We have also surveyed other sites in Missouri and Illinois to establish occupancy rates. No additional populations have been found in Illinois, and material from Missouri was confirmed at least to the generic level, with some material collected for comparative molecular analyses. The snail is threatened by declines in water quality, which likely are associated with changing land use practices accompanying urban sprawl in the greater St. Louis metropolitan area. The Enigmatic Cavesnail receives some protection in Illinois, both as a state-endangered species and because its range overlaps with that of the Illinois Cave Amphipod, federally listed as endangered. Within the drainage basin of Stemler Cave, the Illinois Department of Natural Resources, Illinois Nature Preserves Commission, and a variety of private groups, have been working to acquire natural areas upstream of the cave to help protect watershed integrity. Long-term protection of this species will require acquisition of better scientific data as well as vigilant and thoughtful land management.;