David Etnier
Friday, October 17, 2008 - 8:30-9:00
Biodiversity associated with aquatic habitats in the southeastern United States has been noted by many authors to be extremely high, rivaling or exceeding that of other temperate zones in the world. That this biodiversity is highly imperiled is reflected in numbers of imperiled species in groups with which I am familiar. The Southeast has about 500 species of native freshwater fishes; approximately 100 of these (20%) are jeopardized, 2 are conceded to be extinct, and an additional 3 are likely extinct. Bivalve mussels have fared even more poorly, with 39% (104/269) of southeastern species and subspecies extinct, federally listed, or being evaluated for imperiled status. Freshwater gastropods, with 170 of 313 (54%) southeastern taxa extinct, federally listed, or candidates for listing, are even more jeopardized than the bivalves. Crayfishes, with 338 taxa in North America north of Mexico, have 162 taxa (48%) extinct, endangered, threatened, or of special concern status; most of these occur in the Southeast. Authors responsible for the above information uniformly list alteration of habitats (mostly from the dam-building era) and non-pointsource pollution (= siltation) as co-dominant, causative, anthropogenic factors. High natural rates of endemism, especially in gastropods and crayfishes, exacerbate imperilment problems. We are just beginning to assess these impacts on aquatic insects and other benthic macroinvertebrates.
Keywords: AQUATIC BIODIVERSITY, SOUTHEASTERN UNITED STATES, IMPERILMENT CAUSES