The objectives of the Environmental Monitoring and Assessment Program for Great River Ecosystems (EMAP-GRE) are to (1) develop and demonstrate, in collaboration with states, an assessment program yielding spatially unbiased estimates of the condition of mid-continent great rivers; (2) evaluate environmental indicators for assessing great rivers; and (3) assess the current condition of selected great river resources. The purpose of this paper is to describe EMAP-GRE using examples based on data collected in 2004-2006 with emphasis on an approach to determining reference conditions. EMAP-GRE includes the Upper Mississippi River, the Missouri River, and the Ohio River. Indicators include biotic assemblages (fish, macroinvertebrates, plankton, algae), water chemistry, and aquatic and riparian physical habitat. Reference strata (river reaches for which a single reference expectation is appropriate) were determined by ordination of the fish assemblage and examination of spatial variation in environmental variables. Least disturbed condition of fish assemblages for reference strata was determined by empirical modeling in which we related fish assemblage metrics to a multimetric stressor gradient. We inferred least disturbed condition from the y-intercept, the predicted condition when stress was least. Thresholds for dividing the resource into management-relevant condition classes for biotic indicators were derived using predicted least disturbed condition to set the upper bound on the least disturbed condition class. Also discussed are the outputs of EMAP-GRE, including the assessment document, multimetric indices of condition, and unbiased data supporting state and tribal Clean Water Act reporting, adaptive management, and river restoration.
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Acknowledgement We thank Marlys Cappaert, CSC Corporation, Corvallis, OR, and her data team for IM support. Tatiana Nawrocki, Matt Starry, Roger Meyer, and Jesse Adams, CSC Corporation, Duluth, MN, provided GIS support. Tony Olsen supervised the creation of the survey design. Discussions with John Van Sickle were useful. Comments by Greg Peterson, Thom Whittier, and Mary Ann Starus improved the manuscript. We are especially indebted to the field crews who collected the data and the laboratory staff that processed the samples. The research described herein has been funded wholly by the U.S. EPA. It has been subjected to review by the National Health and Environmental Effects Research Laboratory and approved for publication. Approval does not signify that the contents reflect the views of the agency, nor does mention of trade names or commercial products constitute endorsement or recommendation for use.
- Great rivers
- Least disturbed condition
- Missouri River
- Ohio River
- Reference condition
- Upper Mississippi River