Classification of Wetlands and Deepwater 

 Habitats of the United States 



by 

 Lewis M. Cowardin 



U.S. Fish and Wildlife Service 



Northern Prairie Wildlife Research Center 

 Jamestown, North Dakota 58401 



Virginia Carter 

 U.S. Geological Survey, Reston, Virginia 22092 



Francis C. Golet 



Department of Forest and Wildlife Management 

 University of Rhode Island, Kingston, Rhode Island 02881 



and 



Edward T. LaRoe 1 



U.S. National Oceanic and Atmospheric Administration 

 Office of Coastal Zone Management, Washington, D.C. 20235 



Abstract 



This classification, to be used in a new inventory of wetlands and deepwater habitats of the 

 United States, is intended to describe ecological taxa, arrange them in a system useful to 

 resource managers, furnish units for mapping, and provide uniformity of concepts and terms. 

 Wetlands are defined by plants (hydrophytes), soils (hydric soils), and frequency of flooding. Eco- 

 logically related areas of deep water, traditionally not considered wetlands, are included in the 

 classification as deepwater habitats. 



Systems form the highest level of the classification hierarchy; five are defined— Marine, 

 Estuarine, Riverine, Lacustrine, and Palustrine. Marine and Estuarine systems each have two 

 subsystems, Subtidal and Intertidal; the Riverine system has four subsystems, Tidal, Lower 

 Perennial, Upper Perennial, and Intermittent; the Lacustrine has two, Littoral and Limnetic; and 

 the Palustrine has no subsystem. 



Within the subsystems, classes are based on substrate material and flooding regime, or on 

 vegetative life form. The same classes may appear under one or more of the systems or sub- 

 systems. Six classes are based on substrate and flooding regime: (1) Rock Bottom with a sub- 

 strate of bedrock, boulders, or stones; (2) Unconsolidated Bottom with a substrate of cobbles, 

 gravel, sand, mud, or organic material; (3) Rocky Shore with the same substrate as Rock Bottom; 

 (4) Unconsolidated Shore with the same substrate as Unconsolidated Bottom; (5) Streambed with 

 any of the substrates; and (6) Reef with a substrate composed of the living and dead remains of 

 invertebrates (corals, mollusks, or worms). The bottom classes, (1) and (2) above, are flooded all or 

 most of the time and the shore classes, (3) and (4), are exposed most of the time. The class Stream- 

 bed is restricted to channels of intermittent streams and tidal channels that are dewatered at low 

 tide. The life form of the dominant vegetation defines the five classes based on vegetative form: 



(1) Aquatic Bed, dominated by plants that grow principally on or below the surface of the water; 



(2) Moss-Lichen Wetland, dominated by mosses or lichens; (3) Emergent Wetland, dominated by 

 emergent herbaceous angiosperms; (4) Scrub-Shrub Wetland, dominated by shrubs or small 

 trees; and (5) Forested Wetland, dominated by large trees. 



The dominance type, which is named for the dominant plant or animal forms, is the lowest level 

 of the classification hierarchy. Only examples are provided for this level; dominance types must 

 be developed by individual users of the classification. 



'Present address: Department of Environmental Regulations, 2562 Executive Center Circle, East Mont- 

 gomery Building, Tallahassee, Florida 32301. 



