An Ozark and a deltaic stream in northeastern Arkansas were studied to compare physicochemical and aquatic macroinvertebrate parameters and to determine whether the number and kind of organisms increase downstream. Janes Creek, the Ozark-type stream, is clear, spring-fed and alkaline with a steep gradient and high flow velocity; dissolved oxygen values are not limiting. Big Creek, the deltaic stream, is turbid, low in alkalinity and has a slight gradient and low stream velocity. These streams comprise distinct habitats created by differences in substrate, watershed and land use. A total of 122 taxa were collected in both streams, 62 of which were identified to species. Of the total taxa, 100 were found in Janes Creek and 55 were found in Big Creek. Only 33 taxa were common to both streams. Species diversity indices for Janes and Big Creek stations ranged from 3.272 to 4.454 and 1.822 to 2.905, respectively. Snails which fed on algal film of submerged rocks in pools were characteristic of Janes Creek, whereas oligochaetes which fed on organic detritus were characteristic of Big Creek. Mean numerical standing crop of Big Creek was almost three times that of Janes Creek (726 organisms vs. 265 organisms/m²). Longitudinal zonation was characterized in each stream by an increase in numbers and kinds of aquatic macroinvertebrates downstream. Diversity index values did not completely support this observation, however.
Cather, Mary R. and Harp, George L.
"Aquatic Macroinvertebrate Fauna of an Ozark and a Deltaic Stream,"
Journal of the Arkansas Academy of Science: Vol. 29
, Article 11.
Available at: https://scholarworks.uark.edu/jaas/vol29/iss1/11