Patterns of Imperilment of Southern Appalachian Fishes

Noel M. Burkhead, Stephen J. Walsh, and Robert M. Dorazio
U.S. Geological Survey, Biological Resources Division
Florida Caribbean Science Center, Gainesville, FL

North America north of Mexico has the richest temperate fish fauna in the world. Most of the diversity-about 350 species or 44% of the North American ichthyofauna-occurs in the southeastern United States in the unglaciated highlands of southern Appalachia. Comprised of four physiographic provinces, southern Appalachia is a geologically and environmentally complex area that has and continues to be a major center of evolution in the North American fish Fauna.

The broad impact of southern economic and population growth on aquatic biodiversity is the basis for the Southeast being recognized as a global freshwater conservation hot spot. Imperilment of southeastern freshwater fishes is increasing and has been recently estimated to be as high as 25%. Imperilment in southern Appalachian fishes was examined by comparing the imperiled fraction of the fauna to the nonimperiled across the following attributes: Physiographic province, range size, macrohabitat, vertical orientation in water column, trophic guild, spawning guild, body size, longevity, and fecundity. The resultant matrix of ~350 species by 48 categorical variables was analyzed by running 10,000-iteration randomized sampling of the matrix to construct a statistical model unique to the data set. The data closely approximated a chi-square distribution.

Significant differences were detected between the imperiled and nonimperiled southern Appalachian fishes. In general, small, short lived, benthic-adapted fishes with low-to-moderate fecundity and small-to-moderate ranges were disproportionally imperiled. This pattern of imperilment suggests that degradation of benthic habitats in creeks and rivers is correlated with decline of benthic fishes.