The State of Arkansas has been subdivided into six ecoregions based on the homogeneity of land surface forms, potential natural vegetation, soil types and land uses. Reference streams of various sizes, excluding the large rivers, and with the least amount of point source and non-point source disturbances were selected for intensive physical, chemical and biological sampling. These data are to be used to characterize the streams and establish water quality criteria which will protect all stream uses. Fish communities of the reference streams were distinctively different among the ecoregions and can easily be used to characterize the waters of different ecoregions. Although composed of different species, the composition of trophic feeding levels of the fish community was very similar among the ecoregions. The average number of species collected per sample site was similar among the ecoregions; however, the Arkansas River Valley and the Gulf Coastal ecoregions had the greatest species richness and the Delta ecoregion was the lowest in species richness. Species of fish sensitive to environmental change comprised near 50% or more of the community relative abundance in the Boston Mountains, Ozark Highlands and Ouachita Mountains ecoregions. Delta ecoregion fish populations contained less than 1% sensitive species. Comparisons of the ten most abundant species from each ecoregion by use of a similarity index shows very little similarity among the ecoregions. The Ouachita Mountains and Boston Mountains communities were most similar and the Ozark Highlands community versus Delta and Ozark Highlands versus Gulf Coastal were least similar.
Keith, William E.
"Distribution of Fishes in Reference Streams Within Arkansas' Ecoregions,"
Journal of the Arkansas Academy of Science: Vol. 41
, Article 16.
Available at: http://scholarworks.uark.edu/jaas/vol41/iss1/16