Three strategies guide stream restoration projects: natural channel design (NCD), ecological function, and a hybrid combining NCD and ecological function. The strategy used for a given project is chosen based on individual stream restoration needs. Stream macroinvertebrates are used to indicate stream health and assess stream restoration projects due to the range in tolerance of macroinvertebrate families and their placement into functional feeding groups. However, previous studies have shown that projects focused on improving stream banks did not necessarily result in ecological improvement. Our objective was to determine how the NCD restoration at Cow Creek, Stillwater, OK, affected macroinvertebrates by identifying differences in community structure, functional feeding groups, and abundances between the restored and unrestored reaches of Cow Creek.
Results/Conclusions
While the restoration increased stream bank stability, it also reduced the canopy cover leading to greater sunlight and warmer water temperatures. Based on these differences, we hypothesized that macroinvertebrate densities would be higher in covered, unrestored areas, populations of shredders would be greater in the upstream and downstream covered sections, and populations of grazers would be greater in the restored section than the unrestored due to greater algal densities from the reduced canopy cover. However, macroinvertebrates did not differ between the stream in restored or unrestored sections, regardless of differences in canopy or temperature. Combined, our results are consistent with previous research showing that stream bank restoration does not also improve instream characteristics. As such, restoration efforts designed for one aspect of the stream do not always cause improvement in others.