Beachgrass Action Alert

The nineteenth century naturalist Henry David Thoreau wrote:  “Thus Cape Cod is anchored to the heavens, as it were, by a myriad little cables of beachgrass, and if they should fail, would become a total wreck, and erelong go to the bottom.”  The same could be said of Martha’s Vineyard.

American beachgrass, the common name for Ammophilia brevioligulata is the familiar tall pale green plant with ribbon like leaves that grows along barrier beaches.  The beach is a harsh environment for plants.  Rainfall quickly percolates through the sandy soil before plants can absorb much of it.  This soil is low on rich organic matter and nutrients.  Beachgrass is unique in its ability to withstand temperature extremes, battering by a storm’s high tides and howling winds, and to thrive in the constantly shifting sand of the dunes in which it grows.  You might therefore assume that beachgrass is extremely hardy. In reality it is fragile and highly vulnerable to human impact. 

Ammophilia translates to “lover of sand.”  Beachgrass is called a “pioneer species” because it colonizes the barren foredunes, those that face seaward.  It can withstand being buried in three feet of windblown sand and actually requires the sea’s salt spray!  Beachgrass is the only one of the shore grasses that can adapt to weather.  Its leaves or blades roll up during hot dry weather to conserve water and unroll when it rains.

Dunes are the mounds or ridges of sand that develop above the beach.  They protect the coast from storm waves and the devastation that can result from inland floods. Dunes form by prevailing winds blowing loose sand, like grains of rice, across the beach face, the area between the lowest and highest tides.  The interaction between the nonliving mineral sands and living beachgrass is a kind of nature’s “bioengineering.”  As the leaves get buried in sand, the plant responds by sending up a vertical stem to find light and moisture.  Rhizomes, the underground interconnecting horizontal fibrous stems trap sand grains, as if they were tiny fish in a net, and anchor the plant.  Rhizomes also give rise to additional vertical stems called culms.  In summer beachgrass flowers, producing a spike like seed head taller than the two to three foot leaves.  By stabilizing the dune, beachgrass makes the backside of the dune suitable for other plants, such as beachpea and seaside goldenrod, to take root and grow. 

The Friends of Sengekontacket Inc. hope you will share your beachgrass knowledge by educating others not to trample beachgrass by walking through it rather than using designated paths, by keeping pets out of the beachgrass, by not driving over a dune, or even temporarily placing a bicycle or surf board on a sand dune.  Beachgrass stewardship reflects our attitude toward the Vineyard’s beaches.

This environmental education project is carried out by Friends of Sengekontacket Inc. with funding from the Edey Foundation. 

© Friends of Sengekontacket, Inc., 2008