Fish Assemblage Structure Under Variable Environmental Conditions in the Ouachita Mountains

INTRODUCTION The Ouachita Mountains of Arkansas and Oklahoma contain a suite of river systems that ultimately drain into the Red and Arkansas River basins. The region supports a diverse fish fauna with several endemic species (Robison and Buchanan 1988). The implementation of the Ouachita Mountains Ecosystem Management Research Project (Phase III) by the USDA Forest Service provided us with the opportunity to study how environmental variability influences fish assemblage structure across a large spatial scale incorporating the four Phase III core watersheds.