Vegetative delineation of coastal salt marsh boundaries

Legislation mandating the protection of wetlands, combined with current pressures to convert them to other uses, emphasize the need to determine accurately a wetland-upland boundary We investigated six methods designed to establish such a boundary based on vegetation Each method was applied to a common data set obtained from 295 quadrats along 22 transects between marsh and upland areas in 13 intertidal saline wetlands in Oregon and Washington. The multiple occurrence, joint occurrence, and five percent methods required plant species to be classified as salt marsh, upland, and non-indicator, cluster and similarity methods required no initial classification Close agreement on wetland-upland boundaries determined by the six methods suggests that preclassification of plants and collection of plant cover data may not be necessary to determine the boundary