Biodiversity, or biological diversity, may be defined as the variety of living organisms inhabiting an area. Biologists usually divide 'biodiversity' into three levels: genetic, species and community. Our study is primarily concerned with taxonomic or species diversity, that is we want to know what species occur at the different sites in the rivers we are surveying. However, we are collecting samples so that others can examine the genetic diversity of mussels. Mussel tissue is being deposited with several genetics laboratories where it will be available to other researchers for genetic and systematic studies.

Our study is documenting the number of species and their abundance at riverine sites throughout the Ouachita Uplands. We are examining four groups of aquatic organisms: mussels, benthic macroinvertebrates, meiofauna, and fishes. Benthic macroinvertebrates are organisms such as snails and larval insects that live on the stream bottom. Meiofauna are very small organisms, such as some worms and crustaceans, that live in the spaces between sand and gravel particles under the stream.