Benthic Macroinvertebrate Habitat Associations of the Channelized Middle Missouri River

Benthic macroinvertebrates associated with navigation structures (dikes, dike pools, revetted banks) and abandoned channels on the Missouri River at the Iowa-Nebraska border were sampled in June, August, and October 1983 to determine the invertebrate community structure of these habitats. Invertebrate densities were greatest in the abandoned channel habitat (to over 13,000/m2), while diversities were greatest in the dike and revetment habitats. Greater habitat diversity contributed to greater organism diversity in the dike and revetment habitats while sediment homogeneity and stability presumably contributed to greater organism densities in the abandoned channel habitat. Dike pools had turbulent eddy currents, which constantly stirred bottom sediments and provided a marginal habitat for invertebrate colonization. Burrowing aquatic worms, midges, and mayflies characterized abandoned channels, whereas dikes and revetments were dominated by clinging caddisflies, mayflies, and Hydra, although worms and midges were associated with interstitial sediments. Dike pools were depauperate areas dominated by immature worms