USA Wetlands: Classification

Abstract

In 1979 the United States Fish and Wildlife Service (USFWS) published the Classification of Wetlands and Deepwater Habitats of the United States. In 1996, the Federal Geographic Data Committee adopted the classification as a National Standard. A revised edition of this Standard was published in 2013. The classification system permits a detailed, hierarchical description of vegetated and nonvegetated wet habitats based on vegetative life form, substrate form and composition, water regime, water chemistry, and soil properties. It has been used extensively in habitat mapping, as well as resource assessment and management. Most notably, the classification has supported the National Wetlands Inventory (NWI), which has been ongoing since 1976, and has performed multiple analyses of the character and dynamics of the Nation’s wetlands and deepwater habitats. Digital wetlands data have been produced for the Conterminous United States, Hawaiian Islands, Guam and Saipan in the Pacific Trust Territories, Puerto Rico, US Virgin Islands, and 35% of Alaska. These data have been incorporated in five reports to Congress on the Status and Trends of Wetlands and Deepwater Habitats of the Conterminous United States and more than a hundred regional, state, local, watershed, and special interest reports. All of the digital wetlands data and reports may be downloaded and viewed at: http://www.fws.gov/wetlands. The classification also provides uniformity in concepts and terminology throughout the USA. In support of the classification, the US Army Corps of Engineers maintains a list of more than 8000 plants known to occur in the Nation’s wetlands, while the US Department of Agriculture’s Natural Resources Conservation Service has developed a definition and criteria for identifying hydric soils and has listed hydric soils at state, county, and National levels. The US wetland classification has been cited extensively in the scientific literature and applied internationally.