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Coastal Wetland Definitions

Plant communities along the coastline are dependent on salinity and hydrology. The following definitions are used to identify where the plants in the tables below typically occur. Salinity levels for each area are approximate. In addition to salinity level, it is important to also be aware of the Wetland Indicator Status to properly place plants in the correct hydrologic zone.

  • Saline Marsh – intertidal emergent wetland dominated by grasses, forbs, and shrubs that are tolerant to salinity ranges from moderate to essentially that of sea water (18- to 30-ppt salt).
  • Brackish Marsh – intertidal emergent wetland dominated by grasses, forbs, and shrubs that are tolerant to salinities from slight to moderate (0.5 to 18 ppt salt).
  • Tidal Freshwater Marsh and Swamp – emergent and forested freshwater (<0.5 ppt salt) wetlands dominated by herbaceous plants or trees, respectively, upstream from brackish marshes but where water levels changes are still tidally influenced
  • Mangrove Swamp – intertidal forested wetland with salinities similar to that of saline marshes but are dominated by either red mangrove (Rhizophora mangle), black mangrove (Avicennia germinans), or white mangrove (Laguncularia racemosa).
  • Beaches and Dunes – intertidal and upland (above the mean high tide) dominated by disturbance and drought tolerant grasses and forbs, where wave and wind action is so frequent and disruptive as to prevent the formation of wetlands.