South Carolina Low Country
The Low Country contains one of the most extensive systems of salt marsh and tidal flats in the United States. Its size results from the broad, gently sloping, sandy coast of the US eastern seaboard, coupled with a moderately high tidal range of 5–7 ft (1.5–2 m). Each day, two high tides inundate a vast area of the coastal zone, maintaining a system of channels, creeks, and rivers. The influence of both fresh and salt water here results in some diverse ecological communities. Smooth cordgrass is the dominant grass in the lower marshes, where the ground stays wet and muddy as a result of the tides. From late spring to fall, darker dead-looking sections of a grass called needle rush can also be seen. These two grasses are replaced toward higher ground by sea oxeye and the similar but taller marsh elder.
In the lower marshes and the bordering tidal flats, mud snails, crabs, shrimp, worms, and other tiny inhabitants burrow into the mud, while attached and clinging to the stalks of the grasses are ribbed mussels and marsh periwinkles. Among the fish living in the silty tidal wash are croaker, menhaden, and mullet. Birds living here include marsh wrens and clapper rails.