Lake Index of Biological Integrity Assessments
Source:Clean Water Fund
Activity Type:Assessment/Evaluation, Monitoring, Research
The Index of Biological Integrity (IBI) is a tool that can identify water pollution problems based on how the type and abundance of certain species in a biological community vary from expected conditions. The Minnesota Pollution Control Agency currently uses IBIs for fish and macroinvertebrates (stream-dwelling insects and other critters) to help determine whether streams and rivers are impacted by water pollution. DNR is developing similar tools, using fish and aquatic plants, to identify lakes that may be impacted to support Legacy Amendment assessment efforts. The development of an IBI involves sampling a wide range of lakes, from high-quality systems to those with significant water quality impacts, plus detailed statistical analysis. The DNR's current effort is focused on collecting information about the entire fish community including non-game fish that have not been traditionally sampled by fishery managers and are often more sensitive to watershed and shoreline disturbance. In addition, DNR is beginning work on development of a plant IBI, especially important for assessing shallower wildlife lakes.
About the Issue
Water pollution problems in lakes have traditionally been identified with water chemistry or water clarity samples, which give a brief snap-shot in time for a limited number of pollutants. An IBI tells more about the water's ability to support plant and animal species over the long term. For example, the absence of certain "indicator species," which are sensitive to pollution, points to stress factors that may require further study. Hopefully, the IBI approach can provide an alternative to expensive chemical sampling and can be established using data already being collected for fishery and aquatic plant management purposes.
Start Date:July 2009
Project Details by Fiscal Year
Minnesota Department of Natural Resources
1601 Minneosta Drive