The Long Term Resource Monitoring Program (LTRMP) is conducting the most comprehensive monitoring of macroinvertebrates in the Upper Mississippi River System (UMRS). The LTRMP began monitoring benthic macroinvertebrates in the UMRS in 1992 and continues today with more than 5,500 samples having been collected.

The main objective of the work is to document spatial and temporal trends in selected benthic macroinvertebrates from samples collected by staff at the six LTRMP field stations.

• Pool 4
• Pool 8
• Pool 13
• La Grange Pool
• Pool 26
• Open River

Macroinvertebrates are an important component of the UMRS because they are an important food source for a variety of fish and waterfowl.

Researchers have traditionally used macroinvertebrates as biological indicators of river water quality. An indicator species is defined as a species that has particular requirements with regard to a known set of physical or chemical parameters.

Macroinvertebrates also perform an important ecological function by digesting organic material and recycling nutrients, making them available to plants and animals. Long-term monitoring is intended to provide a better understanding of the conditions needed to support viable macroinvertebrate populations at levels adequate to sustain native fish and waterfowl. This work is an essential ingredient to maintaining a healthy and functional river system.

Benthic samples are collected with a winch-mounted standard Ponar grab sampler. All mayflies, fingernail clams, midges, Asiatic clams, and zebra mussels collected in a Ponar sample are counted in the field. The presence or absence of data are also collected for a variety of other freshwater macroinvertebrates.

The macroinvertebrate database includes information on organism numbers, site descriptions, and habitat information. The database can be accessed via the Upper Midwest Environmental Sciences Center's Web site (http://www.umesc.usgs.gov/data_library/macroinvertebrate/invert_page.html).

Project terminated in September 2001.

Principal Investigator: Jennie Sauer