Southwick Beach State Park - Beachgrass & The Dunes

Beachgrass & The Dunes

The dunes immediately adjacent to the beach support a plant community dominated by beachgrass. The beachgrass grows runners under the surface of the sand that interlock into a ropelike network, and actually builds the dune by trapping sand. Some tall wormwood plants grow amidst the beachgrass, as do cottonwood trees and sand dune willows. Cottonwood is the only dune-forming tree in the area. Sand dune willows are fairly rare in New York State, but are a common woody plant in these dunes. This "beachgrass plant community" stabilizes the dunes against erosion by wind and storm, and enables the growth of a more complex, "poison ivy-dune grape-cottonwood plant community" deeper in the dunes.

Beachgrass growth is disrupted by human and animal traffic. In heavily used regions of the eastern Lake Ontario dunes, foot traffic has eliminated this plant community entirely. Without the beachgrass, the sand dunes are blown away by wind. Starting in the early 1990s, there has been extensive restoration of the beachgrass along eastern Lake Ontario. Wooden "walkovers" have been constructed to manage traffic across the dunes between the beach and interior trails and waterways. The restoration has been accompanied by education and outreach programs intended to reduce traffic across the dunes. The improvement in beachgrass growth has been documented by a "photomonitoring project" from 1995-2005.

Until the 20th Century, the beachgrass in this region would have been the type now known as "Champlain beachgrass", which is found only along eastern Lake Ontario and along Lake Champlain. It is very similar to the common American beachgrass native to the Atlantic coasts of North America, but blooms in July instead of September. "Cape variety" American beachgrass was introduced into the area, and is now mixed with Champlain.