Coastal Ecosystems

The most important coastal systems are beaches and coastal dunes. These are important ecosystems in their own right, but also serve as important habitats for a number of organisms that are residents in other ecosystems.

These ecosystems are also highly attractive for human development. Their geological nature, however, makes it difficult for them to retain their ecological characteristics while being developed.

Beaches and coastal sand dunes often develop where rivers dump large volumes of sand into shallow coastal waters, or where coastal erosion has created large amounts of sandy sediment that can be deposited on the shoreline by wave action. Beaches are often very distinct ecologically from the adjacent mainland, and often contain isolated populations of endemic species.

They are highly dynamic systems.

Barrier island structure

Another view

Barrier beaches are similar, but remain connected to the mainland at one end.

Barrier beaches and islands lie offshore from about 10% of the world’s coasts, and are particularly important off the US Atlantic and Gulf coasts.

A number of ideas have been suggested to explain barrier island formation.The most widely accepted is the mainland beach detachment hypothesis.

Passes and inlets also migrate. Longshore currents remove sand from the upflow side of the pass and deposit it downflow.

Barrier beaches are often home to extensive development.

These developments are often destroyed as the result of natural processes.

Life on Sandy Shores

Can usually see a successional change in plant communities.

Sea oats Railroad vine

Sea grapeSaw palmetto

Cabbage palm

Prickly pear cactus

Live oak hammock

Black mangrove

Red mangrove

A number of terrestrial vertebrates make their home in sandy coastal ecosystems.

A number of birds, like the least tern, require large empty stretches of beach for nesting.

The Perdido Key beach mouse is one of Alabama’s endangered species.

In the Florida Keys, Key deer were reduced to less than 30 individuals in the late 1940’s.

One of the organisms that is most closely tied to sandy coastal ecosystems are the sea turtles.

Loggerhead

Green sea turtle

Leatherback

Hawksbill

Kemp’s Ridley

Olive Ridley

Flatback

In 1982, Congress passed the Coastal Barrier Resources Act, which designates 186 barrier island units extending for 751 miles along the Atlantic and Gulf shoreline as a Coastal Barrier Resource System.

The Coastal Barrier Resource System Table of Contents--U.S.Fish and Wildlife Service

In addition, ten national seashores have been established along the Atlantic, Gulf, and Pacific Coasts. These national seashores are part of the national park system.

National Seashores that are part of the National Park System