Chapter 4 Habitats
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4.3.3 Estuarine Wetland Communities 4.3.3.1 Ecosystem Description
Estuarine wetland communities are coastal landscapes affected by tidal waters in and along the sounds and drowned river mouths (see Section 4.2.14) and include the following themes and subtypes. In addition to the components described here, sand flats, mud flats, and algal mats are part of the estuarine community. Estuarine wetland communities have high and low elevation zones defined by tidal influences. • Salt marsh • Brackish marsh (salt meadow cordgrass, needlerush, smooth cordgrass, and transitional subtypes) • Salt flats • Salt shrub (high and low subtypes) Saltmarshes occur where tides regularly flood the area with undiluted sea water. This environment of repeated flooding and exposure and higher salinity levels limit the diversity of plant species that occur in salt marshes to only a few species. Much of the productivity in salt marshes is likely below ground in organic materials. Saltmarsh and Salt Meadow Cordgrasses dominate these communities, and only a few other vascular plants occur. Algae may also be an important part of plant productivity. The abundance of invertebrates, such as mollusks and crustaceans, indicates the transitional nature of these communities between terrestrial and marine systems. Brackish marshes occur in areas where the tidal waters are partly diluted by fresh water. At low elevation zones they can be low in plant diversity, with Black Needlerush usually dominating vast areas. High-elevation zones contain a significant component of Salt Meadow Cordgrass and Saltgrass. Salt flats occur in fairly small areas of slight depression at the upper edge of salt or brackish marshes. Salty water floods these areas only occasionally. Once flooded, the water is trapped in the depression and evaporates, leaving salt concentrated in the soil. Vegetation is usually a sparse collection of extremely salt-tolerant plants such as Saltgrass and Glasswort. The center of the salt flat may be completely barren. Salt shrub communities occur on the upper edge of salt and brackish marshes, where saltwater rarely reaches or where salt is diluted by freshwater seepage. They are dominated by salt- tolerant shrubs with marsh herbs often occurring in openings.
Estuarine islands are not considered a wetland community, but they are particularly important for nesting terns, skimmers, pelicans, wading birds, and American Oystercatchers. Most have
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2025 NC Wildlife Action Plan
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