Accession Number : ADA323646
Title : Annual Status Report, 1993: Macroinvertebrate Sampling
Descriptive Note : Annual rept.,
Corporate Author : GEOLOGICAL SURVEY ONALASKA WI ENVIRONMENTAL MANAGEMENT TECHNICAL CENTER
Personal Author(s) : Sauer, Jennifer S.
PDF Url : ADA323646
Report Date : FEB 1997
Pagination or Media Count : 26
Abstract : In 1992, macroinvertebrate sampling was initiated in Pools 4, 8, 13, 26, and 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. Mayflies (Ephemeridae), fingernail clams (Sphaeriidae), and the exotic Corbicula species were selected for monitoring. Midges (Chironomidae) were added to the sampling design in 1993. Mayflies, fingernail clams, and midges, members of the soft-substrate community were chosen because they play an important ecological role in the Upper Mississippi River System. Sampling was based on a stratified random design and was conducted at about 125 sites per study area. Mean densities of organisms were weighted by strata for pool or reachwide estimates. Pool 13 had the highest mean number of mayflies (155 sq m), fingernail clams (2,596 sq m), and midges (509 sq m ). The lowest mean number of mayflies, fingernail clams, and midges (7, 1, and 10 sq m, respectively) was encountered in Pool 26. Overall, the impounded areas, including Lake Pepin, tended to support the highest densities of mayflies, fingernail clams, and midges. Substrates with predominantly a silt clay constituent supported the highest mean densities of mayflies, fingernail clams, and midges.
Descriptors : *ECOSYSTEMS, *INVERTEBRATES, *AQUATIC BIOLOGY, *CLAMS, *AQUATIC INSECTS, DENSITY, MONITORING, NATURAL RESOURCES, SUBSTRATES, POPULATION, SAMPLING, CLAY, PATTERNS, RIVERS, MISSISSIPPI RIVER, DIPTERA, ECOLOGY, ILLINOIS, SILT, MUSCIDAE.
Subject Categories : Ecology
Distribution Statement : APPROVED FOR PUBLIC RELEASE