Transient Giants: How Sand Dunes Protect Our Beaches

Seashore symbiosis: The give and take between beaches and sand dunes

Sand Dunes

Sand dunes don’t travel across coastal beaches without paying their way. These rolling hills of sand share a symbiotic relationship with the beaches on which they reside. Dunes require the sand from beaches to form, but beaches rely on the dunes to shield them from the impact of storm surge and high waves. When storms take a toll on the shoreline, dunes counter the erosion by replenishing the beach with sand.

Dune formation often starts with a small pile of beach debris, such as seaweed or marsh grass. As waves propel more sand onshore and winds distribute dry sand across the beach, grains slowly accumulate around the debris and form a small mound. Dune grass seeds also find their way to these budding dunes, where they germinate, sprout and capture even more sand. Before you know it, a new dune has formed.

To survive, these waves of sand require the stabilization offered by grasses, shrubs and other coastal vegetation—and only a special kind of plant can withstand the drying winds, low soil moisture, intense sunlight and blowing sand that come with this formidable habitat. Lichens, fungi, moss, grasses, wildflowers and shrubs are among the hardy vegetation that typically take root in these mobile homes.

But despite their remarkable resilience, these plants are surprisingly sensitive to human activity. Walking or driving over dunes can destroy surface vegetation, causing roots to die off and exposing the dune to wind erosion.

Because these dunes are critical to preventing beach erosion, the National Aquarium is working to return stability to areas like Virginia Beach, which has been compromised due to storms like Hurricane Isabel. Myriad animals depend on this habitat. Sea turtles nest in sand dunes, while rodents use them to carve out extensive networks of burrows. Snakes, lizard, flies, beetles and invertebrates—such as crabs and mollusks—all call these dunes home.

With the help of our conservation team and dedicated volunteers, we’re transplanting native grasses to restore this habitat and protect the watershed’s coastlines. Join us! Find out how you can get involved and join our conservation team for one of our restoration events.


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