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Geography: Barrier Islands

Human Interaction

Barrier islands are invaluable to protecting the mainland coast from erosion. But what happens when the islands themselves are developed? The resulting loss of beach habitat leaves shore birds and sea turtles without a familiar place to lay their eggs, causing a decline in their populations. As plant life is destroyed, birds and fish must seek food and shelter elsewhere. If the barrier islands are their primary habitats, the wildlife that depends on them is also put at risk. The ultimate effect of these changes on humans as well as wildlife may not be understood until long after it occurs. In some areas, people have undertaken restoration projects to try to rescue these precious ecosystems.

As a barrier island, Palm Beach faces harsh winds and storms directly, with no real defense against erosion. In their efforts to save the coastline, coastal residents have options to consider, including the use of steel groins and sea walls, and the cultivation of sand dunes. Periodically, the beach is restored by collecting sand offshore and delivering it to the island by sand dredged and deposited by pipes. This new sand also provides habitats for birds and sea turtles.

The bright lights of coastal development – streetlamps, illuminated parking lots, and buildings – can be a killer for sea turtles. Instinct drives hatchlings from their nests on beaches toward the brightest horizon, which would ideally be moonlight reflecting on the ocean’s surface. Bright artificial lights confuse the turtles’ internal navigation systems, causing them to head toward the wrong light and become easy prey for sand crabs, sea birds, and traffic. There are now ordinances in place to regulate this “light pollution” that disorients the turtle hatchlings, and sometimes the adults.

In the last century, Palm Beach County lost much of its mangroves. Early settlers to south Florida saw them as useless, mosquito-infested obstacles to shoreline development and trimmed or removed them. By 1985, eighty-five percent of all mangroves had been removed, but today ecologists realize the important role of mangroves in coastal ecosystems. With the help of volunteers, several projects are replanting mangroves in the Lake Worth Lagoon. To ensure the plants’ future, they are also restoring their ecosystem by removing invasive species, such as Australian pine and Brazilian pepper.