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Comparative Wetland Monitoring and Assessment of Coastal Wetlands
Using a 3-tiered approach, the coastal wetlands in southern New England are assessed with:
- a landscape analysis
- a field, rapid method, and
- a detailed field evaluation for some targeted, reference sites.
The landscape analysis (tier 1) uses available inventory maps of intertidal, emergent and associated wetlands, aerial photography, and a Geographic Information System to assess condition of the wetlands and disturbances (e.g., ditching, fragmentation, barriers to landward migration) at a coarse scale. In the second assessment tier, the condition of the marsh is described through a field evaluation using measures of hydrology, plants, and soil. The plant metrics include descriptions of communities, species, and percent cover. Soil metrics include measures of penetration resistance and macro-organic matter or peat fragment content in the surface layer of the soil. Area of disturbances such as tidal restrictions, outfalls, and invasive species are also observed on-site. In the final tier, detailed biological (e.g., avifauna, infauna, plants, fish) and geochemical measurements are made at a targeted subset of reference sites of low to high watershed disturbance as indicated by land use development and watershed nitrogen inputs. The marsh landscape stressors (i.e., hydrological alterations, ditching, fill and fragmentation, barriers to landward migration, point sources) were significantly related to the percent development (i.e., residential, industrial, urban) in a 150 meter buffer surrounding the wetland units. There were significant relationships between the rapid assessment plant metrics and the marsh landscape stressors. In addition, the more detailed (tier 3) plant measurements were significantly correlated with the rapid assessment (tier 2) plant measures at a subset of reference sites, verifying the utility of the more rapid measures. A reference-based evaluating scheme is under development to describe the relative condition of the coastal wetlands.
EPA Scientists Developing Rapid Methods to Assess Coastal Wetlands
Some peer-reviewed references related to the project
McKinney, R.A., and Wigand, C. 2006. A framework for the assessment of the wildlife habitat value of New England salt marshes. EPA/600/R-06/132. Office of Research and Development. Washington, DC 20460.
Chintala, M, Wigand, C, and Thursby, G. 2006. Comparison of Geukensia demissa populations in Rhode Island fringe salt marshes with varying nitrogen loads. Marine Ecology Progress Series, 320: 101 - 108.
Wigand, C. McKinney, R.A., Chintala, M., Charpentier, M., and Grofman, P. 2004. Denitrification enzyme activity of fringe salt marshes in New England (USA). Journal of Environmental Quality 33, 1144-1151.
Wigand, C. McKinney, R.A., Charpentier, M.C., Chintala, M., Thursby, G. 2003. Relationships of nitrogen loadings, residential development, and physical characteristics with plant in New England salt marshes. Estuaries 26, 1494-1504.
Thursby, G, B. and Abdelrhman, M. A. 2004. Growth of the Marsh Elder Iva frutescens in Relation to Duration of Tidal Flooding. Estuaries. 27(2):217-224.
McKinney, R.A., W.S. Nelson, M. Charpentier, and C. Wigand 2001. Ribbed mussel nitrogen isotope signatures reflect nitrogen sources in coastal salt marshes. Ecological Applications 11 (1), 203-214.
Wigand, C., R. Comeleo, R. McKinney, G. Thursby, M. Chintala, and M. Charpentier 2001. Outline of a new approach to evaluate ecological integrity of salt marshes. Human and Ecological Risk Assessment 7 (5), 1541-1554.