Golf ball-sized snail is critical link in Everglades restoration

April 19, 2001

GAINESVILLE, Fla. — The success of the $7.8 billion Everglades restoration project may rest on the apple snail — a golf ball-sized creature that is a key component of the food chain, say researchers from the University of Florida and two Florida water management districts.

“The apple snail is probably one of the most important animals in Florida’s wetlands, but it’s one of the least studied,” said Franklin Percival, an associate professor with UF’s Institute of Food and Agricultural Sciences. “There just isn’t much interest in studying something that doesn’t have obvious economic or aesthetic importance.”

Dale Gawlik, a senior scientist with the South Florida Water Management District, said because so many animals eat the apple snail, it could provide an early warning if restoration efforts are creating problems in the environment.

“The snail is an important indicator of how the ecosystem itself is doing,” Gawlik said. “If we lose the apple snail, then we can be pretty sure it will affect animals further up the food chain. For example, the endangered snail kite and small alligators that rely on the apple snail for a large part of their food supply.

“It’s just a chain reaction that goes on and on from there,” he said.

Percival said a general lack of knowledge about the apple snail indicated the need for an in-depth study.

“Practically nothing was known about these snails,” Percival said. “And since they are so important, we need to know exactly how they operate and start studying their basic biology.”

In order to track the snails’ movements and learn about their habits and needs, researchers attached tiny radio transmitters to the snails’ shells.

Phil Darby, a postdoctoral associate in UF’s department of wildlife ecology and conservation who worked on the research, said the studies revealed that the snail is hardier than anyone had expected.

“Apple snail populations have adapted to the periodic dry periods that are a natural part of the Florida wetland landscape,” Darby said. “Our research shows they can survive out of water for as long as four months.

“In fact, dry-downs may be essential for apple snails because they help maintain the plant life on which the snails lay their eggs,” he said.

Steve Miller, an environmental scientist with the St. Johns River Water Management District, said it is important to study all animals that make up an ecosystem. That gives water managers the knowledge to make decisions that affect both the environment and area farmers, he said.

“For example, our apple snail studies showed that water use by orange growers is not detrimental to the snail kite or the apple snail,” Miller said. “This has allowed us to integrate water management to include agricultural interests, flood control interests and environmental interests all at the same time.

“Without the information obtained through this research, we wouldn’t have been able to do that,” he said.

Percival said the research into the apple snail indicates why resource managers must consider all animals in an ecosystem.

“There are numerous demands on the available water supplies including agriculture, Everglades National Park or the Loxahatchee National Wildlife Refuge and all of the people living on the eastern side of the Everglades,” Percival said. “The water management districts need to remember that the wildlife is equally important — and at the base of that food chain are these snails.

“The various water management districts are now recognizing that to accommodate all of these interests, the special needs of some special animals must also be considered,” he said.

The study was funded with about $400,000 in grants from the St. Johns and South Florida water management districts, the Florida Fish and Wildlife Conservation Commission and the U.S. Geological Survey.