MAJOR WETLAND TYPES OF 

 THE UNITED STATES 



Wetlands occur in every state of the country and due to 

 regional differences in climate, vegetation, soil and hy- 

 drologic conditions, they exist in a variety of sizes, 

 shapes and types. Although more abundant in other areas, 

 wetlands even exist in deserts. 



The Service's classification system (Cowardin. et al. 

 1979) groups wetlands according to ecologically similar 

 characteristics. It first divides wetlands and deepwater 

 habitats into five ecological systems: (1) Marine, 

 (2) Estuarine, (3) Riverine, (4) Lacustrine, and (5) Palus- 

 trine (Figure 3). The Marine System generally consists of 

 the open ocean and its associated coastline (Figure 4). It is 



mostly a deepwater habitat system, with marine wetlands 

 limited to intertidal areas like beaches, rocky shores and 

 some coral reefs. The Estuarine System includes coastal 

 wetlands like salt and brackish tidal marshes, mangrove 

 swamps, and intertidal flats, as well as deepwater bays, 

 sounds and coastal rivers. The Riverine System is limited 

 to freshwater river and stream channels and is mainly a 

 deepwater habitat system. The Lacustrine System is also 

 a deepwater dominated system, but includes standing wa- 

 terbodies like lakes, reservoirs and deep ponds. The 

 Palustrine System encompasses the vast majority of the 

 country's inland marshes, bogs and swamps and does not 

 include any deepwater habitat. Characteristics of the ma- 

 jor wetland types in the U.S. are described in the follow- 

 ing sections. The discussion focuses on estuarine and 

 palustrine wetlands because they are the most abundant 

 types. 



MARINE SYSTEM 

 (OCEAN) 



LEGEND 

 System boundary 

 Estuarine System 

 Riverine System 

 \\ Lacustrine System 

 Palustrine System 

 Rocky shore 

 Intertidal beach 

 Tidal flat 

 Aquatic bed 



^3 Emergent wetland 

 f\^ Forested wetland 



Fig. 4. Diagram showing major wetland and deepwater habitat systems. 



