Biologically Significant Illinois Streams: An Evaluation of the Streams of211 Illinois Based on Aquatic Biodiversity

摘要

The objective of the authors' study was to identify the state's most biologically211u001esignificant streams so that protection efforts can be concentrated on a 211u001ereasonable number of streams and the objective of protecting 100% of Illinois' 211u001estream-dependent biodiversity can be realized. The identification of the 211u001ebiologically most significant streams will provide a basis for decisions by 211u001egovernmental and other organizations as to which streams should be protected for 211u001etheir biodiversity and which will be used for transportation, industrial, or 211u001eother consumptive uses. The recognition of outstanding streams will affect 211u001edecisions made by lawmakers and governmental agencies. It is anticipated that the 211u001eNature Preserves Commission, The Nature Conservancy, and other conservation 211u001eorganizations will purchase easements, dedicate preserves, and otherwise protect 211u001ethe identified outstanding aquatic ecosystems. Efforts at stream management for 211u001esport fishes and other forms of recreation will be enhanced through the 211u001eidentification of the least degraded streams in Illinois. An earlier and 211u001econtinuing study to identify biologically significant streams is the Biological 211u001eStream Characterization (BSC). The BSC is a stream-quality index developed by the 211u001eIllinois Department of Conservation and Environmental Protection Agency to 211u001ecategorize streams and is based largely on fish populations, water quality, and 211u001eaquatic macroinvertebrates. In the BSC, stream segments are categorized from 'A' 211u001e(highest quality) to 'E' (lowest). Twenty-four stream segments currently are 211u001econsidered to be in the 'A' category, and 50 in the 'B' category (next highest). 211u001eBecause of the high diversity of fishes they support, the authors consider all 211u001e'A' streams to be among the most biologically significant streams in Illinois.