marshlands

Marshlands are wetlands characterized by water-saturated soils and vegetation dominated by herbaceous species such as grasses, sedges, and reeds. They occur in low-lying areas where groundwater, surface water, and, in coastal zones, tidal action create saturated soils for extended periods. Marshes can be tidal, receiving regular salt or brackish water, or freshwater, sustained by rivers and rainfall. They are typically not densely forested, distinguishing them from swamps.

Marshlands support high primary productivity and a diverse array of species. Their open vegetation and shallow waters provide important breeding and feeding habitat for waterfowl, wading birds, fish, amphibians, and invertebrates. Marsh soils often accumulate organic matter, making them effective carbon sinks, and their plant structure helps trap sediments, filter nutrients, and reduce flood risk.

Salt marshes line temperate and subtropical coasts, where tides bring saline water and plants such as cordgrass and pickleweed dominate. Freshwater marshes occur inland in floodplains, along lakeshores, and in river deltas, with vegetation like cattails and rushes. Marshes are typically seasonally inundated or persistently waterlogged and lie between open water and drier uplands.

Marshlands have been drained, dredged, and converted to agriculture and urban development, reducing biodiversity and natural flood buffering. Restoration efforts focus on rewetting drained land, restoring natural hydrology, and reestablishing tidal exchange where appropriate. They are protected under various conservation frameworks and designated as Ramsar sites or other reserves to safeguard their ecological services. Marshlands are widespread across many regions and continue to be among the most productive and threatened wetland ecosystems.