It varies by season. In the spring and summer, brown pelicans are dominant in the Perdido Bay area. In the winter it’s the double-breasted cormorant. But other birds use the roosts as well, including gulls, terns, herons and egrets.
Seagrass beds, sometimes called “the prairies of the sea”, span hundreds of thousands of acres in the Gulf of Mexico. Here in Florida, we enjoy some of the world’s best.
These vast fields of green are underwater meadows that:
But seagrass beds are dying at an alarming rate – reduced as much as 90 percent in some bays across the Gulf. The Conservancy is determined to reverse that trend, and is experimenting in Florida with techniques that may prove helpful around the world.
“Every acre of seagrass that we lose is a big blow to native species that depend upon that habitat,” says marine scientist Laura Geselbracht, who directs the Conservancy’s work in Florida. “One acre can support as many as 40,000 fish and 50 million invertebrates.”
Because seagrass beds primarily occur in very shallow water, they are vulnerable to damage from motor-driven boats. And what a boat propeller does in 5 seconds may take from 5 to 50 years to heal!
By tearing up sand and ripping out grasses, a boat propeller can gouge holes and make long trails through the seagrass. These are called scars because they look remarkably like pale scars when viewed from the air. One or two scars can heal themselves, but constant small cuts will gradually overwhelm a seagrass bed’s ability to recover.
The Conservancy works in several Florida locations to:
In 2009, scientists began experimenting with two primary restoration techniques. One technique used effectively in northwest Florida is elegant in its simplicity – well, if a technique involving PVC pipe, galvanized screws and bird poop can be called elegant. But what this method lacks in dignity, it makes up for in effectiveness.
Pioneered in the Florida Keys, where more than 600 boat groundings are reported every year, a “bird stake” technique is quite straightforward:
Bird poop (also known as guano) is high in phosphorus – an important nutrient for seagrass growth. Studies from the Keys have shown that the re-growth of seagrass is more rapid when propeller scars are heavily fertilized by birds. Bird stakes appear less expensive and more successful than some other, more intensive techniques.
A second seagrass restoration technique uses 3-foot long, sausage-shaped, cotton fabric tubes. Filled with sediment and placed in boating scars, sediment tubes been used by the Conservancy in the Crystal River area. The fabric degrades in about one year, while seagrasses send out rhizomes or root-like structures that re-colonize the area.
Charlotte Harbor, a significant southwest Florida estuary, has significant scarring of seagrass beds near commercial marinas. There, the Conservancy will compare the effectiveness of the two techniques.
“These experiments are significant,” says Geselbracht. “We plan to test the two procedures against each other and against nature at Charlotte Harbor to see which works better and under which circumstance.”
To prevent further damage, the Conservancy is engaging the boating community by:
We couldn’t be successful without our partners. Especially in marine habitats, where the Conservancy is by law unable to purchase the area we wish to protect, effective zoning is very important.
Special thanks to:
National Fish and Wildlife Foundation
Shell Marine Habitat Program
National Oceanic and Atmospheric Administration
April 25, 2012