Wetland Ecological Integrity: An Assessment Approach

Study Area: Waquoit Bay watershed, southeastern Cape Cod
Period: 1996-1998
Funds: National Oceanic and Atmospheric Administration (NOAA) and NOAA's Coastal Services Center, with in-kind match and support form various non-Federal partners

Download 1995-1997: Waquoit Bay Wetland Assessment Project Report (PDF, 8.22M)

The goal of the Waquoit Bay Pilot Wetland Assessment Project was to develop, test, and refine a transferable approach for wetlands evaluation to determine the effects of adjacent land uses and nonpoint sources (NPS) of pollution on the condition of these aquatic resources. Thirteen wetland study sites were selected to: 1) represent the three dominant types of wetlands in the watershed (salt marshes, bordering riverine wetlands, and isolated depressional wetlands), 2) reflect the major land use types present (residential and commercial development, transportation, agriculture, and recreation). At each site, biological, chemical, and hydrological measurements were made to assess the relative ecological health and functioning of these wetlands. In addition, several rapid assessment methods and techniques were used and the results were examined in light of actual on-site measurements. Through the development and implementation of this pilot project, project investigators were able to evaluate the accuracy and effectiveness of an array of rapid wetland evaluation methods and promote their inclusion in a transferable assessment approach.

Based on the analysis of the onsite biological, hydrological, and chemical measurements, there is discernable variation between study sites. The data indicate a pattern of ecological condition associated with certain land uses and land use practices. Compared to control (or reference) study sites, wetlands with a higher degree and intensity of proximate land uses show a marked shift in biological species and community composition; dissimilar hydrology; and increased concentrations of nutrients, sediments, and pathogenic bacteria. Statistical analysis revealed very close correlations between the results of the rapid assessment methods and the field-based indicators. This assessment has enabled the investigators to identify which wetland sites are exhibiting signs of ecological and functional impairment, to characterize what the adverse effects are, and to infer the potential sources or causes of impairment. This information can be utilized to guide decision-makers as they attempt to address NPS pollution and implement measures to mitigate existing problems and prevent future ones. The wetlands assessment approach has valuable applications for wetlands management, protection, and restoration.