You're walking along the beach and see the signs along the edge of beach -- PLEASE DO NOT CLIMB ON THE DUNES (photo credit). But it's fun, so why do we need to protect dunes?
Dunes, marshes, and wetlands are nature's sponges. They help keep the water where it belongs (in our waterways and oceans) and out of where it doesn't belong (your house, street, basement, etc). Healthy dunes help protect the land behind the dune from storm damage and protect the beach from erosion. I snapped a couple of pictures on Edisto Beach SC last week. These photos do a great job of demonstrating the beach damage that occurs when we build on or destroy dunes. This first picture is the beach at Edisto Beach State Park, where dunes are protected. Note the size of the beach and the vegetation buffer.
After taking this picture, I wandered down the shore, just a couple of hundred yards. In this area, houses are often built ON the dunes, rather than behind them. Note the lack of vegetation (except under houses) and the width of the beach.
Not only is the first beach a much more pleasant place on a summer day, it's also much better protection when storms hit. The same is true of marshes and wetlands. These areas provide natural absorption of rain and stormwater.
So avoid the urge to scramble on the dunes and ensure that the beach remains healthy!