Landscape
More than half of Assateague Island National Seashoreâs 48,000 acres is comprised of near-shore and estuarine waters, and the interplay between these waters and the barrier island affects nearly every aspect of life in this dynamic coastal environment.
The geography of the island itself is in a state of constant flux, continuously being reshaped by the elemental forces of wind and water. Powerful storms can dramatically alter the shoreline in a matter of hours, as waves wash over the beach and reshape the island from ocean to bay. Other forces sculpt the landscape in less obvious ways. Exposure to salt spray, lack of fresh water, and isolation from the mainland are subtle, but powerful influences on the Islandâs species composition. Over time, these conditions have produced a community of plants and animals uniquely suited to the extremes found at the edge of the sea.
Flora and fauna
While Assateagueâs wild horses are perhaps the islandâs best-known inhabitants, other large mammals also roam the park, including the native white-tailed deer Odocoileus virginianus and the non-native sika deer Cervus japonica, a diminutive species of Asian elk introduced to Assateague during the 1920âs.
Other inhabitants are less conspicuous than the large mammals. Seven species of frogs and toads depend on fresh water ponds in the center of the island for breeding, and a variety of snakes, such as the black rat snake Elaphe obsoleta obsoleta, can be found across the forests, dunes, and marshes preying on rodents, small birds, or toads. Numerous invertebrates such as fiddler crabs Uca ssp. and mud snails Nassarius ssp. play key roles in maintaining the health of the islandâs salt marshes. Even the seemingly barren beaches provide habitat for nocturnal ghost crabs Ocypode quadrata, red fox Vulpes vulpes, and raccoons Procyon lotor, who scavenge the crustaceans, fish, and other organic matter washed in by the tides.
Many bird species make their home on Assateague on a seasonal basis. Shorebirds by the tens of thousands depend upon the islandâs protected foraging and resting areas during their twice-yearly transcontinental migrations. Each fall, large flocks of waterfowl such as snow geese Chen caerulescens begin arriving at Assateague where they will spend the winter traveling between the sheltered bay and salt marshes and fallow farm fields on the mainland.
Finally, the coastal waters that surround Assateague Island teem with animal life. The sheltered, nutrient rich waters of the estuary formed by the island provide ideal breeding and spawning habitat for many aquatic species, some of which, like the blue crab Callinectes sapidus, are commercially important to the local area. Each spring a variety of fish, including spot Leiostomus xanthrurus, Atlantic menhaden Brevoortia tyrannus and summer flounder Paralichthys dentatus migrate into the estuary to breed. Later, the juvenile fish provide an abundant food source for birds, marine mammals, and larger fish.