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Jamaica Bay Park

Salt Marshes in New York City Parks - Jamaica Bay Park

This text is part of Parks’ Historical Signs Project and can be found posted within the park.

Salt marshes play a critical role in the support of human life, acting as natural filtration systems by trapping pollutants that would otherwise contaminate our bays and oceans. Salt marshes have the ability to absorb fertilizers, improve water quality, and reduce erosion. They are also among the richest wildlife habitats.

Jamaica Bay is an 18,000-acre wetland estuary surrounded by the Rockaway Peninsula to the South, Brooklyn to the West, and Queens to the East. Comprising an area almost equal to that of Manhattan, the bay consists of numerous islands, a labyrinth of waterways, meadowlands, and two freshwater ponds. The wetlands provide a unique environment for both wildlife preservation and urban recreation. Enclosed by the Rockaway Peninsula and protected from the Atlantic Ocean, the region currently hosts over 325 species of birds, 50 species of butterflies, and 100 species of finfish. A favorite stop for migratory waterfowl, the area is an integral part of the larger, regional ecosystem. One of New York City’s most extraordinary natural resources, Jamaica Bay remains highly undeveloped.

When the last of the glaciers melted 7,000 years ago, the oceans rose to their present levels. Sediments washed from the land were deposited offshore in narrow sandy strips, forming long islands parallel to the shoreline. These barrier beaches received the pounding surf on their ocean side, but had calm, protected bays behind their landward shores. While the waters were calm enough for vegetation to take root, the presence of saltwater made survival difficult. One species, however, saltmarsh cordgrass (Spartina alterniflora), was able to colonize the flat expanses of sand and silt, which were covered twice a day by the ocean’s tides. Today, the grass is still found along the Atlantic coast.

As this specialized grass spreads, its stems trap floating debris. Sediments and particles of decaying matter slowly build up, forming nutrient-rich mud. This mud, called detritus, supports life on the marsh. It is the basis of a complex food web in which energy is passed from one organism to another. The fiddler crab (Uca) and ribbed mussel (Geukensia demissa) have developed a mutually beneficial relationship with the cordgrass. While the crabs and mussels benefit from feeding on decaying matter trapped within cordgrass roots, cordgrass gains from the fiddler’s burrowing, which aerates the soil, and the mussel’s excretion, which provides necessary nitrogen.

At the end of each season, the cordgrass dies, creating a spongy peat. Each year’s peat layer raises the surface of the marsh, enabling it to colonize new territory. A variety of plants with less salt tolerance can colonize the peat, as it is out of the range of most of the high tides. This causes the formation of two separate plant communities, the intertidal marsh and the salt meadow. A third type of salt marsh community is the mudflat. Each of these communities has its own distinctive vegetation, insects, fish, birds, and mammals that have adapted to survive in a saltwater environment. While salt marshes do not have a very wide variety of species, the volume of life present is remarkable.

In the summer, wading birds, including great blue (Ardea herodias), little blue (Florida caeruleai), and tricolored (Egretta tricolor) herons, and great (Casmerodius albus) and snowy (Egretta thula) egrets, feed in the shallows and mudflats of Jamaica Bay. The osprey (Pandion haliaetus) has come back to Jamaica Bay Park after decades of decline tied to the use of the pesticide DDT. In the winter, thousands of ducks, geese, and other waterfowl congregate in Jamaica Bay’s protected waters. Each fall and spring, waves of migrating shore-birds descend on the bay’s mudflats to feed.

Since industrialization, human activity has destroyed many marshes. Where marshes are disturbed, common reed (Phragmites australis) often grows in place of cordgrass. Since reeds do not decompose into as nutritious a substance as cordgrass, a reed marsh does not contribute as much to coastal ecosystems as a cordgrass marsh. In the last 200 years, humans have also filled over 80 percent of the city’s original salt marshes for construction. While recent conservation efforts have improved the condition of marshes, this valuable ecosystem continues to disappear from the City at an alarming rate. Scientists fear that the salt marshes of Jamaica Bay may completely vanish within 20 years.

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