Definition: In this wetland Class, emergent plants—i.e., erect, rooted, herbaceous hydrophytes, excluding mosses and lichens—are the tallest life form with at least 30% areal coverage. This vegetation is present for most of the growing season in most years. These wetlands are usually dominated by perennial plants. All Water Regimes are included except Subtidal and Irregularly Exposed. Not all Water Regimes apply to all subclasses. 


Description: In areas with relatively stable climatic conditions, Emergent Wetlands maintain the same appearance year after year. In other areas, such as the prairies of the central U.S., violent climatic fluctuations cause them to revert to an open water phase in some years (Stewart and Kantrud 1972). Emergent Wetlands are found throughout the U.S. and occur in all Systems except the Marine. Emergent Wetlands are known by many names, including marsh, wet meadow, fen, prairie pothole, and slough. Areas that are dominated by pioneer plants, which become established during periods of low water, are not Emergent Wetlands and should be classified as Vegetated Unconsolidated Shores or Vegetated Streambeds. 


Subclasses and Dominance Types: 


  • Persistent -  In this Subclass, the areal coverage of persistent emergents exceeds that of nonpersistent emergents. Persistent emergents are emergent hydrophytes whose stems and leaves are evident all year above the surface of the water, or above the soil surface if water is absent. Persistent Emergent Wetlands occur only in the Estuarine and Palustrine Systems. 


Persistent Emergent Wetlands dominated by saltmarsh cordgrass (Spartina alterniflora), saltmeadow cordgrass (S. patens), big cordgrass (S. cynosuroides), Roemer's rush (Juncus roemerianus), narrow-leaved cattail (Typha angustifolia), and mash-millet (Zizaniopsis miliacea) are major components of the Estuarine Systems of the Atlantic and Gulf Coasts of the U.S. On the Pacific Coast, woody saltwort (Salicornia virginica), broom seepweed (Suaeda californica), seaside arrow-grass (Triglochin maritimum), and California cordgrass (Spartina foliosa) are common dominants. 


Palustrine Persistent Emergent Wetlands contain a vast array of grasslike plants such as cattails (Typha spp.), bulrushes (Scirpus spp.), saw grass (Cladium jamaicense), sedges (Carex spp.); and true grasses such as manna grasses (Glyceria spp.), slough grass (Beckmannia syzigachne), and common river grass (Scolochloa festucacea). There is also a variety of broad-leaved persistent emergents such as purple loosestrife (Lythrum salicaria), Mexican dock (Rumex mexicanus), swamp loosestrife (Decodon verticillatus), and some species of smartweeds (Polygonum). 


  • Nonpersistent - In this Subclass, the areal coverage of nonpersistent emergents exceeds that of persistent emergents. Nonpersistent emergents are emergent hydrophytes whose stems and leaves are evident above the water surface, or above the soil surface if surface water is absent, only during the growing season or shortly thereafter. During the dormant season, there is no obvious sign of emergent vegetation. Nonpersistent Emergent Wetlands occur in all Systems except the Marine. Nonpersistent emergents also include species such as green arrow-arum (Peltandra virginica), pickerelweed (Pontederia cordata), and arrowheads (Sagittaria spp.). Movement of ice in Estuarine, Riverine, or Lacustrine Systems often removes all traces of emergent vegetation during the winter. Where this occurs, the area should be classified as Nonpersistent Emergent Wetland.

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