Implementation and Evaluation of a Rapid Assessment Technique for New England Salt Marshes


Debora Fillis

Advisor: Shimon Anisfeld


Historically thousands of species of fish, wildlife and plants indigenous to wetlands have been threatened by development. Agriculture, transportation facilities (including highways, ports and air terminals) and all manner of industrial, commercial and residential buildings have invaded former wetlands. Although legislation designed to protect wetlands from this type of destruction has been enacted, remaining wetlands are being further degraded through non-point pollution sources, toxic spills, and invasive species. Since there is no specific federal legislation to protect wetlands, several coastal states, including Connecticut, have adopted policies to curb the elimination of wetlands.

The Tidal Wetland Act, passed by the Connecticut legislature in 1969, strictly limits marsh destruction. Unlike current federal regulations, this law explicitly protects wetlands, limiting direct losses to 100 square meters per year, an area less than half the size of a basketball court. It requires additional compensation for these losses through mitigation or restoration projects. The shortfall of this legislation lies in the fact that indirect losses are not considered. The ambient conditions of marshes are not systematically monitored, so managers don't know how to address alterations from non-point sources, invasive species, sea level rise and hydrologic modification.

It is understandable that state agencies have not approached this problem. The current federal assessment methods are complicated, expensive and often too unwieldy for small state agencies or conservation organizations to implement. As a result, over forty different wetland evaluation techniques have been created by organizations to meet their specific needs. The result is a collection of diverse protocols with a variety of metrics, ranging from scientifically rigorous, to qualitative, to descriptive. Such multiplicity creates immense difficulties in comparing wetland health between different regions and protocols. In order to create a new and comprehensive protocol all existing methodologies were reviewed to identify common themes and important ecological indicators. Ecologists from the Environmental Protection Agency and managers from Massachusetts Coastal Zone Management, provided input to develop an assessment that considers the time and budget constraints of mangers while maintaining scientific rigor. Rather then narrowly meeting the needs of a specific organization, this integrated approach incorporates the best wetland science into a realistic management tool.

The protocol follows a proven methodology described in the EPA publication Elements of a Wetland Monitoring and Assessment Program. It includes a landscape assessment as well as a site based rapid assessment. The landscape analysis uses National Wetlands Inventory mapped inter-tidal wetlands, aerial photography, and GIS data to assess the condition of coastal wetlands at a coarse scale. Using a random stratified sample, selected sites are characterized using the following metrics: landscape position, size, shape, exposure, aquatic edge, tidal flushing and associated habitat. The geomorphology and hydrology data will be used to classify and stratify the wetlands in later analyses. Disturbances that can be detected using remote data, such as ditching/draining, fill/fragmentation and land use in the buffer are also assessed.

In the second phase, a rapid assessment protocol is conducted on-site to verify the landscape analysis and determine the condition of and disturbances to the marsh. The condition of the marsh is defined as the state of an observed salt marsh in comparison to the state of a standard reference salt marsh with respect to its physical, chemical and biological attributes, as described by measures of hydrology, plants and soils. The plant metrics include large-scale descriptions of plant communities as well as species composition and percent cover. Soil metrics include estimates of sediment resistance and plant fragment volume. In addition, anthropogenic disturbances, such as tidal restrictions, outfalls and invasive species, are observed on-site. Measures from both the landscape and rapid assessment will be used to determine reference condition and then to create a condition-scoring regime for coastal wetlands throughout New England.

By creating a condition assessment protocol and implementing it in various salt marsh sites, this project addresses two problems: the lack of monitoring data and the lack of resources to collect the data in Connecticut. Several states are implementing this protocol allowing for a more comprehensive and comparative analysis of coastal wetlands in New England. This will equip policy makers with the information needed to compare regulations and restoration efforts between states. Eventually, other coastal New England states, including Maine and New Hampshire, may adopt this method to provide New England with a comprehensive data set for regional salt marsh condition.

Intact salt marsh ecosystems are an integral part of the cultural heritage of New England coastal communities. Quahogs, flounder, herons and osprey are important to New Englanders, especially the fishing and birding communities. Monitoring coastal wetlands leads to more effective conservation, management and ultimately the improvement of habitat for marsh dependent fish and birds.

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15 April 2005