Florida wildlife and water managers are worried about an invasive snail that is wreaking havoc on the state's billion-dollar effort to remove chemicals from the fragile Everglades.

The South American apple snail first appeared in large numbers in 2010, according to Audubon Florida science coordinator Paul Gray, and was initially seen as a potential savior of an endangered bird, the snail kite.

During the prior decade the number of kites, a gray bird with a hooked beak, had fallen to about 700 from 3,400 as their main food source, the native apple snail, became scarce after years of drought and hurricanes.

The abundance of South American apple snails, a popular aquarium pet native to Brazil and Argentina, helped the bird’s numbers recover to 1,200 this year.

"These snails are new, and this is the first time something like this has ever happened in Florida," Gray said.

In 2010 Florida Audubon, part of the National Audubon Society conservation group, successfully lobbied the Florida Fish and Wildlife Conservation Commission to hold off reducing their food source, Gray said.

"The snails are all the kites eat, when they're starving they try to eat turtles or crayfish but that can’t sustain them," he added.

However, last summer hordes of the snails, which are larger and survive better than the native species, devoured much of the vegetation in a 750-acre man-made marsh designed to filter phosphorous out of the Everglades.

“There were millions of these snails in there,” said Larry Gerry, a storm water treatment coordinator for the South Florida Water Management District.

Officials now fear the snails, if not contained, could pose a threat to the rest of the 57,000 acres of marshes built at a cost of $2 billion to rid the fragile wetland of agricultural runoff.

The high levels of nutrients, which are removed by the same plants the snails like to feed on, can cause algal blooms that clog the water system and starve out existing wildlife.

“We’re hoping that this is an unusual event, if it’s not then we have a real challenge ahead of us,” Gerry said.

In another effort to help preserve Florida’s vast swamps, the Everglades Foundation last week launched an international competition offering $10 million to anyone who devises a new method for removing phosphorous from the swamp waters and recycle it for agricultural use.