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EVALUATING THE INTEGRITY OF SALT MARSHES IN NARRAGANSETT BAY SUB-ESTUARIES USING A WATERSHED APPROACH
Citation:
Wigand, C, R A. McKinney, M Chintala, M Charpentier, AND G B. Thursby. EVALUATING THE INTEGRITY OF SALT MARSHES IN NARRAGANSETT BAY SUB-ESTUARIES USING A WATERSHED APPROACH. Presented at 5th Annual NHEERL Symposium: Indicators in Health and Environmental Risk Assessment, Research Triangle Park, NC, June 6-8, 2000.
Description:
A watershed approach to examine measures of structure and function in salt marshes of similar geomorphology and hydrology in Narragansett Bay is being used to develop a reference system for evaluating salt marsh integrity. We describe integrity as the capability of a salt marsh to provide key ecosystem services including water quality maintenance, wildlife habitat, food production, erosion control, and recreation/cultural use. Indicators of these services are being developed from measures of ecosystem structure and function in marshes of varying anthropogenic stress based on watershed. land patterns (i.e., percent residential, industrial, agricultural, and natural lands) and nutrient inputs from discharge streams. Significant correlations between the watershed characterization, nutrient concentrations, and stable nitrogen isotopic signatures of mussels were found. We also examine patterns of water transit and how various natural lands (i.e., forests, inland wetlands, and brush lands) act as nutrient sinks. The sink % transit and the discharge stream nutrient concentrations were significantly correlated. The landscape structure of the marsh including the number of plant zones and the extent of dominant plant species were significantly correlated with the watershed indicators. In addition, denitrification enzyme activity in the high marsh sediments was significantly correlated with land use and soil drainage class in a 200m buffer zone associated with the salt marsh. We are working towards developing indicators of salt marsh condition, and the marsh landscape structure appears to be one variable that links with two key services: erosion control and wildlife habitat. This abstract does not necessarily reflect US EPA policy.