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Imperiled Aquatic Species Index


The Indicator

Maryland DNR's Wildlife and Heritage Division lists particular species, including some species of amphibians, fish, crayfish and mussels, as rare, threatened or endangered. Information on where these aquatic animals have been found is also maintained to help assure their habitats are disturbed as little as possible by human activities.

To develop the index mapped in this indicator, distributions of these aquatic animals within the 8-digit watersheds were determined using Maryland Biological Stream Survey data and were scored from 0 - 10, based on the number of sites with rare species, their status (endangered, rare...), and the diversity of aquatic animals. The indicator, which points primarily to the condition of natural resources might also be considered to suggest vulnerability to human- induced adverse impacts; it was used in the Unified Watershed Assessment to help determine watersheds classified for conservation.

The presence of rare, threatened or endangered species indicates the presence of suitable habitat, usually unmodified or minimally modified by human activity. Species are conserved by preserving their habitat. It should be noted that while an 8-digit watershed may score poorly according to several of the criteria used in this indicator, there may be a small pocket or stream where rare, threatened or endangered animals live, also that some threatened or rare species can live in an area that suffers from several types of pollution.

Indicator Use

The preservation of biological diversity is a policy of the State of Maryland. Watersheds highly rated for this indicator offer additional opportunities to protect the State's biological diversity.

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