Multiyear synthesis of the macroinvertebrate component from 1992 to 2002 for the Long Term Resource Monitoring Program
Dates
Publication Date
2004-12
Summary
In 1992, macroinvertebrate sampling was begun in Pools 4, 8, 13, and 26; the Open River Reach of the Mississippi River; and La Grange Pool of the Illinois River as part of the Long Term Resource Monitoring Program. Long-term monitoring is needed to detect population trends and local changes in aquatic ecosystems. We selected mayflies (Ephemeroptera), fingernail clams (Pisidiidae), and the exotic Corbicula species for monitoring. Midges (Chironomidae) were added to the sampling design in 1993 and zebra mussels (Dreissena polymorpha) were added in 1995. Sampling was based on a stratified random design and conducted at approximately 125 sites per study area. Mean densities of taxa were weighted by strata for extrapolation. The poolwide [...]
Summary
In 1992, macroinvertebrate sampling was begun in Pools 4, 8, 13, and 26; the Open River Reach of the Mississippi River; and La Grange Pool of the Illinois River as part of the Long Term Resource Monitoring Program. Long-term monitoring is needed to detect population trends and local changes in aquatic ecosystems. We selected mayflies (Ephemeroptera), fingernail clams (Pisidiidae), and the exotic Corbicula species for monitoring. Midges (Chironomidae) were added to the sampling design in 1993 and zebra mussels (Dreissena polymorpha) were added in 1995. Sampling was based on a stratified random design and conducted at approximately 125 sites per study area. Mean densities of taxa were weighted by strata for extrapolation. The poolwide estimated mean densities of mayflies, fingernail clams, and midges were all within the range of variation observed historically. Over the last 11 years of sampling, the northern study areas supported the highest densities of the target organisms.
Final report submitted to U.S. Army Corps of Engineers from the U.S. Geological Survey, Upper Midwest Environmental Sciences Center, La Crosse, Wisconsin
