Current and Recent Historical Freshwater Mussel Assemblages in the Gulf Coastal Plains

This study qualitatively surveyed freshwater mussel assemblages at 24 sites in the Choctawhatchee, Yellow, and Conecuh-Escambia river drainages of southeastern Alabama and northwest Florida in 2004. A specific focus of the study was to determine the current status of seven narrowly endemic candidate species: Margaritifera marrianae, Fusconaia escambia, Hamiota australis, Pleurobema strodeanum, Ptychobranchus jonesi, Quincuncina burkei, and Villosa choctawensis. Presence-absence analysis was used to compare 2004 data to recent historical records from the 1990s. There was no significant difference between the number of taxa found in the 1990s and in 2004. There was, however, a significant decrease from the 1990s to 2004 in the number of candidate species found at a site and the number of sites at which candidate species were found.