Prehistoric and modern freshwater mussel (mollusca: bivalvia: unionoidea) faunas of the Tennessee River: Alabama, Kentucky, and Tennessee

Abstract

The Tennessee River, approximately 1050 km in length, originates with the confluence of the French Broad and Holston rivers at Knoxville, Knox County, Tennessee, USA. It flows southwest to about Huntsville, Alabama, where the mainstem changes to a north-westerly direction across northern Alabama, then flows north along the western edge of Middle Tennessee toward its confluence with the Ohio River in Kentucky. Approximately 159 450 specimens of freshwater mussels recovered from 15 prehistoric aboriginal sites, reported in the literature and/or identified by the authors, represent at least 75 species. At least 24 of these species occurred throughout the entire length of the mainstem Tennessee River. Collections from the 1800s and throughout the major dam construction era (1920s–mid 1940s) showed a distinct reduction in the distribution and diversity of mussels from the prehistoric period. Today, the river, now a series of impounded reservoirs along its entire length, shows a further reduction in species diversity coupled with significant changes in assemblages from those of prehistoric and pre-impoundment periods. Several populations of indigenous mussel taxa, once abundant throughout the river, are now reduced to a few isolated and functionally extinct (non-reproducing) relict individuals. The majority of species adapted to shoal areas were extirpated or became extinct as a result of impoundment or other detrimental anthropogenic factors. Copyright © 1999 John Wiley & Sons, Ltd.