The Gulf Islands National Seashore, a part of the National Park Service, is a 150-mile stretch of barrier islands and coastal land in Mississippi and Florida. Gulf Island National Seashore (GUIS) covers about 95,000 acres. This land consists mostly of barrier islands that lie along the Florida and Mississippi Coast. The warm waters of the northern coast of The Gulf of Mexico feeds eleven separate parts that include bayou, salt marshes, and snow-white beaches. Five sections are in Mississippi; the remaining six portions are in Florida. The Gulf Island National Seashore was created in 1971 through the joint efforts of concerned environmentalists in the two states and is the largest of the ten National Seashores.
Basically, barrier islands are just large piles of sand created by the power of the sea. These islands seem to be permanent, but in fact they are continuously changing. Sometimes, nature speeds the process up with hurricanes. Barrier islands buffer the mainland from storms and create shelter for a variety of plant and animal species on the islands themselves as well as in the bayous on the mainland.
The islands that make up Gulf Islands National Seashore are made of quartz sand eroded and washed down rivers from the Appalachian Mountains. A sand dune these days was possibly once, thousands of years ago, a mountaintop near the South Carolina border. .
Powerful currents pushed the quartz sand into the Gulf of Mexico. Currents gradually built long, thin ridges of sediment on the shallow sea floor. Sand continued to deposit, the ridges grew higher and eventually barrier islands were created. Over time, birds, wind and even waves, dropped seeds on the sand. Despite storms, they germinated and took root. Today these plants held down the sand and help to stabilize the island.
Barrier Island (Flora).
The barrier island ecosystem is broken up into four communities. They are: Beach dune, Interdunal, Upland Woody, and Salt Marsh communities.