Tall-form Spartina alterniflora (Smooth Cordgrass) is the dominant vegetative species in low marsh areas.
[2] This species provides shelter and cover for Fiddler crabs (Uca pugnax), ribbed mussels (Geukensia demissa), waterfowl, wading birds, shorebirds, muskrats, and commercially important fish and shellfish.
[1][8][5] Coastal wetlands, such as salt marshes, can sequester carbon at a rate up to ten times that of a mature tropical forest.
[4][6][10] Coastal wetlands, such as salt marshes, with low elevation gradients are the ecosystems that will be first affected by and have to adapt to increased sea level rise(SLR).
[10] Depending on the Intergovernmental Panel on Climate Change (IPCC) RCP scenario, 60-91 percent of salt marshes in a meta-analysis study will not be able to keep up with future rates of SLR.
[10]Increased thermal expansion and increased water supplied to oceans due to higher global temperatures associated with anthropogenic carbon dioxide emissions have caused the rates of SLR along the United States’ Atlantic coast to range from 0.6 to 4 millimeters per year as of the year 2021.
[5] Coastal development, such as roads and houses, prevents salt marshes from migrating inland away from the coast as sea level rises.
[13] Upland vegetation is replaced by halophyte marsh species as a result from increased soil salinity and moisture.
[14] Runoff carries pollutants, including but not limited to fertilizers, sediment, waste, and litter, as well as freshwater into marshes.
[14] The specific ecological effects and their magnitudes vary depending on the concentrations, frequency, and chemical makeup of runoff pollutants.
[citation needed] If it accumulates over vegetation for sufficient period of time, it will block sunlight and smother the plants underneath.
[18] When purple marsh crab populations remain unchecked, they will "mow down" S. alternilfora and increase the number of burrows in the soil.
Common restoration strategies include recovery of tidal exchange, recovery of sediment characteristics, reconstruction of soil level, conversion of dredged sediment to salt marsh, control of invasive species, and restricting boating and other water vehicles.