Barrier Island Ecology

We Love Our Barrier Islands

Three of the fourteen barrier islands on the Georgia coast are National Wildlife Refuges; Blackbeard, Wassaw, and Wolf Islands are valuable components of a string of barrier islands that protect the coast and serve as hotspots for wildlife.

Protecting these special places is vitally important for the future of wildlife and people. 

What Are Barrier Islands?

Barrier islands are dune-covered deposits of sand lying almost parallel to the mainland that are separated from the mainland by a lagoon or marsh.

Barrier Islands border about 1/3 of North America’s coasts, and over 10% of the world’s coastlines

How did they form?

Some argue that powerful ocean currents piled sand on top of sandbars over time. Others attribute their creation to the product of melting glaciers and rising sea levels during the ice age.

Sea oats are extremely important for dune stabilization on barrier islands. Their massive root system is capable of holding soil and sand in place, even during extreme weather events such as hurricanes.

Importance of barrier islands

Climate Change Resiliency 

True to their name, barrier islands form a barrier between the ocean and the mainland. This means they protect the mainland from sea level rise, storms, and hurricanes, which are becoming more extreme due to climate change.  

Wildlife and Biodiversity 

In addition, barrier islands have many important functions that benefit fish and wildlife. The marshes sheltered by barrier islands absorb pollutants like a sponge, and serve as a nursery for young fish, shrimp, and crabs. The water passages formed between marshes and barrier islands support between 75-95% of all marine species at some point in their lives.

Barrier islands also serve as an important stop for migratory birds. In fact, they support a greater variety of bird species than any other natural area in the continental United States.  

Barrier Islands and Birds

Migratory birds use barrier islands as nesting grounds and as stopover sites during their long journeys to rest and feed. 

Should I flush birds?

When humans and pets “flush” birds, meaning they make them fly away, the birds are forced to waste precious energy needed to complete their journey. In addition, flushing nesting shorebirds exposes their nests to the brutal sun, causing death of eggs and hatchlings.

Do your part to protect migratory birds by keeping dogs on leash and keeping your distance from birds on the beach.  Stay off of the dunes and the narrow strip of beach between the base of the dunes and the highest tide mark, which is usually covered with dead grass and other debris.  These are critical habitat areas for shorebirds and sea turtles.  

Shape-shifting islands

Barrier Islands shape-shift?

Powerful waves and storm surges collide with dunes, shifting the deposits of sand and naturally changing the shape of barrier islands.

Generally, barrier islands of the south Atlantic coast naturally migrate slowly southward when left alone. 

Human impacts on natural shape-shifting

Unfortunately, sea level rise is eroding the beaches and taking sediment out to sea faster than the sand can be replenished naturally.

Other human impacts, such as the damming of rivers that carry new sediment, building infrastructure on barrier islands, and attempts to impede natural movement of sediment have led to more loss of sand and put barrier islands at risk of disappearing.  

Hurricane Irma

In 2017, Hurricane Irma pushed massive amounts of water across our barrier islands and into areas further inland. As a result, the southern tip of Blackbeard is now permanently separated by water from the rest of the island.   

Are you a Barrier Island Brainiac?

Use the information from this page to select the true statement from the list below.