Terrapins are by far the most publicly-viewed reptiles in most of Long Island, and are a significant component of the visitor experience at Jamaica Bay Wildlife Refuge. We use our Jamaica Bay Terrapin Research Project as a vehicle for citizen science and environmental education. Many of our volunteers have never been to Jamaica Bay before, have never seen a wild animal close up, have never held a turtle.
Terrapins also impact other wildlife because terrapins are keystone species in both estuarine and nearby coastal ecosystems. This is partially because of their predation on crustaceans, crabs, mollusks and other invertebrates. For example, terrapin predation has been shown to dramatically reduce the abundance of periwinkles (Littorina sp.) (Levesque and Fauth 1999). Periwinkles, in turn, are important predators of salt marsh cordgrass (Spartina alterniflora), one of the most important plants in American salt marshes. Control of periwinkle populations limits periwinkle impacts on Spartina (Silliman and Bertness 2002), and thus protects Spartina. In addition, terrapins move enormous quantities of nutrients and calories from the ocean to land in the form of eggs. Terrapin eggs and hatchlings are eaten by a variety of predators. For example, terrapin eggs containing 300,000 Kcal were eaten by raccoons on a Jamaica Bay beach in a single year (Feinberg and Burke 2003). Eggs missed by vertebrates are often predated by plant roots, which absorb nutrients that are important for their growth in this nutrient-poor environment (Stegmann et al. 1988, Feinberg and Burke 2003).
New York Times article on raccoon egg predation: