Marshes

Marshes are wetlands dominated by herbaceous vegetation rather than by trees. They form where soil remains waterlogged for extended periods, creating hydric soils and conditions that favor grasses, sedges, reeds, and rushes over woody plants. Marshes can be freshwater or saline, depending on the source and movement of water.

Freshwater marshes occur along rivers, lakes, and floodplains, while salt or tidal marshes line coastlines, estuaries, and inlets where tides bring in saline or brackish water. In freshwater marshes, plants such as cattails and bulrushes are common; in salt marshes, Spartina and other salt-tolerant species predominate. The plant community and hydrology influence the animal life present, including birds, fish, amphibians, and invertebrates.

Ecologically, marshes are highly productive and provide important ecosystem services. They filter pollutants, moderate floodwaters, stabilize shorelines, and act as significant carbon sinks by storing carbon in plant biomass and soils. They also support migratory routes and breeding grounds for various species.

Formation and maintenance depend on sediment supply and water regimes. Human activities such as drainage, drainage canalization, dredging, and coastal development can degrade or destroy marshes. In coastal areas, sea-level rise poses additional threats by altering salinity, inundation patterns, and sediment dynamics.

Conservation and restoration efforts focus on reestablishing natural hydrology, protecting surrounding landscapes, controlling invasive species, and rehabilitating native vegetation to recover ecological function.