Soil Indicators of Wetlands
Since the beginnings of scientific study of wetlands, soils have been recognized as an important feature of wetlands. Plant ecologists and geologists alike found that the nature of the soils had a profound effect on plant growth and the formation of peat deposits (a mineral resource of considerable economic value). In the 1950s, the U.S. Fish and Wildlife Service (FWS)’s first wetland classification system made reference to hydromorphic, halomorphic, and alluvial soils being associated with the nation’s wetlands (Shaw and Fredine, 1956). Today, the predominance of undrained hydric soil is a key attribute for identifying wetlands for wetland inventories and federal regulation (Cowardin et al., 1979; Environmental Laboratory, 1987; Federal Interagency Committee for Wetland Delineation, 1989). Following the lead of the federal government, many states are using soils in combination with vegetation and hydrology indicators to identify and delineate potentially regulated wetlands (e.g., Florida, Maine, Maryland, Massachusetts, Michigan, New Hampshire, New Jersey, New York, Pennsylvania, Vermont, Washington, and Wisconsin), although there is variation in the use of these indicators. Connecticut has relied strictly on soil types for identifying inland wetlands for regulatory purposes since 1972. Local governments in New Hampshire also use soil types to define wetlands for local ordinances due to technical support from Natural Resources Conservation Service (NRCS) soil and water conservationists.