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In 1989, the U.S. Environmental Protection Agency (EPA) initiated the Environmental Monitoring and Assessment Program (EMAP). Part of the program (EMAP-Wetlands) is intended to provide quantitative assessments of the status and long-term trends in the ecological "health" of wetland resources on both regional and national scales. Short-term goals of EMAP-Wetlands are to develop standardized protocols to measure and describe the environmental quality of wetlands, report estimates of wetland quality in selected regions, and develop formats for reporting program results. Longer-term goals include trend detection and diagnostic analyses to identify plausible causes for degraded or improved wetland quality.

EMAP-Wetlands will implement its program using a phased approach in high-priority regions. The program selected prairie wetlands as a national priority. These wetlands are of high value to waterfowl and other wildlife but suffer losses due to agricultural drainage and flood control projects. These losses are of concern to public and private conservation agencies. In 1992, the EPA and the U.S. Fish and Wildlife Service's Northern Prairie Wildlife Research Center jointly initiated a pilot project designed to test indicators of wetland quality in the PPR. A major objective of the project was to test selected landscape- and field-level indicators of environmental quality of wetlands by discriminating between wetlands in highly disturbed (agricultural) and less disturbed (grassland) landscapes. Wetland quality is difficult to define a priori, so the approach was to select study wetlands within these landscapes as a proxy for wetlands within "impaired" and "healthy" landscapes. A panel of individuals with regional experience in wetland research proposed a list of wetland attributes to test. These attributes included those at the landscape level as well as those related to the wetland fauna, vegetation, hydrology, pedology, water and soil chemistry, and anthropogenic and climatic stressors.

Here we report the results of tests dealing with vegetation in wetlands lying in extremely-disturbed and slightly-disturbed landscapes. Extreme disturbance of prairie wetlands is almost entirely attributable to agriculture, where over half the wetland basins can be cultivated, even in a wet year (Stewart & Kantrud, 1973). We tested the indicator value of abundance and species richness of vascular hydrophytes, amounts of standing dead vegetation, litter, open water. and unvegetated bottom. We also tested the area of plant communities and the average water depth in those communities within selected wetland zones.