Deep water habitats are defined by Cowardin and 

 others (1979) as permanently flooded lands below the 

 deepwater boundary of wetlands. Generally, this bound- 

 ary lies at a depth of 6.6 ft (2 m) below the low water 

 level, the maximum depth to which most emergent plants 

 normally grow. However, when emergent plants occur 

 beyond this limit, that boundary is the edge between wet- 

 lands and deepwater habitats. 



Five classification levels are defined in the classifica- 

 tion system. Brief descriptions of them follow. 



Systems — There are five systems described according 

 to similarities of general hydrologic, geomorphologic, 

 chemical, or biological factors. The systems relate to gen- 

 eral kinds of water bodies, such as lakes and running water. 



Subsystems — There currently are 10 subsystems 

 based on depth and submergence of the substrate by 

 water or permanence of water. 



Classes — There are currently 55 classes based on the 

 general nature of the substrate (rock bottom or rocky 

 shore), or on general life form of vegetation (forested 

 wetland or wetland with emergent vegetation). 



Subclasses — There are currently 23 subclasses based 

 on specific kinds of substrate, such as bedrock, sand, or 

 mud; or on general life form of vegetation, such as needle- 

 leaved evergreen forest, broad-leaved deciduous forest, 

 or floating vegetation. Subclasses in many cases are the 

 same among classes. 



Dominance types — Dominance types are based on 

 dominant species of plants or animals supported by a spe- 

 cific substrate subclass within particular systems. For 

 example, red mangrove (Rhizophora mangle) occurs 

 within the broad-leaved evergreen forested wetland of the 

 estuarine system. 



Examples of subclasses and dominance types as they 

 relate to vegetation are shown in table 2. 



Modifiers are used to more precisely define the levels 

 of the classification system. These include: 



• Water regime: There are two primary modifiers, 

 tidal and nontidal. The tidal modifiers affect the 

 marine and estuarine systems around the coastal 

 areas and are determined largely by oceanic tides. 

 Nontidal modifiers affect the riverine, palustrine, 

 and lacustrine systems and are related to fluctuations 

 of water in inland lakes, streams, and other water 

 systems. 



• Water chemistry: There are two primary modifiers, 

 salinity and hydrogen ion concentration (pH). Salin- 

 ity is applied to all habitats, and freshwater habitats 

 are further subdivided by pH levels. 



• Soil: There are two primary modifiers, mineral and 

 organic material. They are used with the wetlands 



portion of the classification system because the deep- 

 water habitats, by definition, are never considered to 

 have soil. Soil, as a modifier of wetlands, is neces- 

 sary. The depth, temperature and moisture regimes, 

 chemistry, and mineral and organic matter content 

 of soil influence the kinds and amounts of vegetation 

 and organisms wetlands can support. 

 The wetlands and deepwater habitats classification, 

 as part of the framework for a national ecological land 

 classification system, provides a skeleton for evaluating 

 water as a life support system. Consider fish and fish- 

 eries, for example. The subclasses delineate the nature of 

 the bottoms of lakes, rivers, and streams, according to 

 cobble-gravel, sand, rubble, mud, organic or bedrock. 

 These features are important for evaluating fish spawn- 

 ing areas and spawning success. The presence of animal 

 organisms that live within hydric soils or in other sub- 

 strates provide food for associated animals. Vegetation 

 can be evaluated according to its potential to provide 

 cover and food for fishes. Similar analogies can be made 

 in relation to waterfowl, certain amphibians, mollusks, 

 and other water dependent animals. 



The linkage between the wetlands and deepwater 

 habitats classification system and the vegetation classifi- 

 cation previously described occurs generally at the domi- 

 nance type level of wetlands and the series level of this 

 vegetation classification. For example, a vegetation series 

 in the forest class of Alaska includes black spruce (Picea 

 mariana) and is described as occurring on wet, boggy 

 sites with poorly drained organic soils (Viereck and Dyr- 

 ness 1980). A dominance type in the palustrine system of 

 Cowardin and others (1979) is black spruce {Picea mari- 

 ana). Another example would be a vegetation series of 

 smooth cordgrass (Spartina alterniflora) in the subclass 

 of the medium tall grassland occurring in salt marshes 

 along the eastern and southern coasts of the United States. 

 A species of dominance type of the same plant occurs in 

 the persistent emergent wetland of the estuarine system of 

 Cowardin and others (1979). 



In wetland, if soils are present, they are hydric. A list 

 of hydric soils is being prepared by the Soil Conservation 

 Service. This list forms the linkage between the soil and 

 wetlands elements of the classification system. 



The new wetlands and deepwater habitats classifica- 

 tion is generalized. It is open ended and incomplete below 

 the class level; only examples are given for dominance 

 types. The system is insufficiently detailed at the domi- 

 nance type level to provide for detailed project planning. 

 Other levels corresponding, for example, to the series and 

 association levels of the vegetation element need to be 

 developed. However, the system, as currently described, 



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