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Marine Places

Cape Cod Salt Marshes

Salt marshes are the dominant type of coastal wetland around Cape Cod, although about a third of the region’s marshes have been lost or severely degraded within the past 100 years. These salt marshes occur behind barrier beaches or spits and within estuarine systems, and have developed over the past 3,000 years in response to sea-level rise. They mainly consist of high marsh, where the dominant plant species is saltmeadow cordgrass, with some scattered areas of low intertidal marsh, dominated by smooth cordgrass. The low marsh areas are flooded twice daily and the high marsh twice a month, during the highest spring tides. The largest individual marsh is the Great Salt Marsh to the west of the town of Barnstable. With deep channels running through it, this is a popular area to explore by kayak.

The marshes around Cape Cod serve as a breeding and foraging habitat for a diversity of brackish and freshwater animals. Among these are two rare and protected bird species, the northern harrier and least tern, and two endangered reptiles, the diamond-backed terrapin and eastern box turtle. Restoring degraded salt marshes on Cape Cod is regarded as a top priority for many regional and national conservation organizations. Restoration will allow these wetlands to regain their function as a barrier protecting the coastline from storm surges and as a natural sponge that filters pollutants and excess nutrients from the water runoff in the region.

Cape Cod Salt Marsheszoom image
  • Atlantic Ocean Northwest
  • Type Salt marshes
  • Area 30 square miles (80 square km)
  • Location Cape Cod, eastern Massachusetts, US
Cape Cod Salt Marshes habitat mapzoom image