Note that the data published in the 2002 State of the Nation’s Ecosystems Report as well as the 2003 and 2005 Web-Only Updates have been superseded by the 2008 Report and thus should be used with caution. For the most recent data, purchase the 2008 Report from Island Press.

This technical note is also for the stream habitat indicator for the freshwater system.

The Indicator

The habitat quality of streams and rivers is dependent upon the presence of an appropriate, but changing, mix of habitat features. Key among these are the presence of riffles and pools, size distribution of streambed sediments and embeddedness (degree to which larger gravel and cobbles are buried in silt), amount of large woody debris, and bank stability, although different stream habitat rating methods may measure additional characteristics.

In addition, habitat quality is a relative value, meaning that it must be evaluated in relation to the habitat needs of the native flora and fauna in a region. Therefore, protocols to measure stream habitat quality generally provide for calibration according to a regional reference—that is, stream habitat quality is measured against the values that would be found in a relatively undisturbed or “natural” reference stream in that region. Finally, all stream habitat quality measurement protocols measure a variety of parameters, but not all combine these parameters into a single overall index.

Stream habitat quality measurement is an area of significant current research work. Following are references for four efforts that have or are developing regional or national protocols for this purpose.

References

Maryland Department of Natural Resources; Maryland Biological Stream Survey. http://www.dnr.state.md.us/streams/mbss/

U.S. Environmental Protection Agency. Rapid bioassessment protocol. Developed guidance to state agencies. http://www.epa.gov/owow/monitoring/rbp/

U.S. Environmental Protection Agency, Office of Research and Development, National Health & Environmental Effects Research Laboratory. May 2000. Biological indicators for monitoring riparian forest condition. Proceedings of a workshop. Corvallis, OR. EPA-600-R-00-048. COR-00-077.

U.S. Geological Survey. National Water Quality Assessment Program. Stream habitat monitoring protocol. http://water.usgs.gov/nawqa/protocols/OFR-93-408/habit1.html