Indian River Lagoon Species Inventory
Barrier Island Habitats
The extensive barrier island system along the east coast of Florida is the largest in the United States, consisting of approximately 189,300 hectares (467,700 acres) (Kaplan 1988). In east central Florida, barrier islands separate the Atlantic Ocean from the Indian River Lagoon (IRL) and are an important defense against hurricanes and major storms, buffering mainland Florida against large waves, heavy winds, and storm surges.
Barrier islands are dynamic features of the landscape that form in two ways: 1) from longshore drift currents move sands southward along the coast; and 2) from the emergence of underwater shoals (Otvos 1981). It is believed that Florida's barrier islands originated during the Pleistocene epoch (1.75 million to 11,000 years ago) when rises in ancient beach and their associated sediments lithified into coquina (rock). Traces of this coquina system, called the Anastasia Formation, can be found from St. Augustine to Boca Raton, Florida (Tanner 1960b).
Whether barrier islands begin as simple sandbars, or as
emerged shoals, they gradually accumulate sand due to wave action and winds. It
is this build up of sand along the coast that forms the well developed beaches,
dunes and maritime forests along Florida's coast. Wave action is constantly at
work eroding sand from some areas of the barrier island system, while
simultaneously depositing this eroded sand into different areas via longshore
drift, storms and hurricanes.
The substantial system of barrier islands in the area of the Indian River Lagoon encompasses a variety of habitat types. In the immediate vicinity of the shoreline are beaches, dunes, and swales. Beyond the beach zone are coastal strand, also called scrub, maritime hammocks, spoil islands, and the mangrove fringes that border the Indian River Lagoon.
Select a barrier island habitat to explore:
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