An Index of Environmental Integrity Approach for the US Mid-Atlantic Region

John F. Paul

US Environmental Protection Agency, NHEERL (B205-01), Research Triangle Park, NC 27711

Environmental conditions in the Mid-Atlantic region of the United States have been documented in a series of reports that use "environmental report cards" to summarize the condition of individual natural resources (e.g., estuaries, streams, forests, and landscapes) over the entire region and within major subregions. An "index of environmental integrity" (IEI) approach has been developed and is illustrated using the information content of these report cards to evaluate the overall condition throughout the region. The development of the index builds upon the concepts underlying the development of the index of biotic integrity (IBI): index is simple summation of individual metric values, individual metrics respond in monotonic fashion to environmental stress, uniform scaling for metrics, and application of index doesn't lose information contained in the individual metrics. The index relies upon the validity of information that went into the individual resource environmental report cards. The IEI approach is a four-step process: (1) select individual components for the index, (2) calculate subindex values for each of the individual components, (3) aggregate the subindex values into the overall index, and (4) interpret the index values. The IEI approach is illustrated by applying to the Mid-Atlantic estuaries and wadeable streams in the Mid-Atlantic Highlands. Because the IEI approach is new, application should not be made without considering issues such as evaluation of the selection of the indicators, weighting scheme, uncertainties, and appropriate way to interpret the values.

Keywords: Mid-Atlantic United States, multiresource assessment, environmental integrity, ecological index, environmental report card, estuaries, streams

An Index of Environmental Integrity Approach for the US Mid-Atlantic Region

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