The Everglades is a vast wetland that once covered most of South Florida. Since the 1800s, agriculture and other development have replaced much of the original wildlife habitat. Now, a proposal by the region's biggest sugar producer to quit farming and sell its land to the state for permanent conservation has raised new hopes for the Everglades ecosystem. And as Véronique LaCapra reports, it could give a big boost to restoration efforts. 

The Everglades wetland encompasses an area of about 5,000 square kilometers in South Florida

The Florida Everglades is the largest remaining subtropical wetland in the United States. But over the past century or so, half of the floodplain has been drained for human use. In the late 1940s, a massive government engineering project built roads, canals, and levees, to make even more dry land and fresh water available for farming and other development. The project drastically altered the flow of water in the Everglades, destroying approximately 5,000 square kilometers of wildlife habitat.

All this has brought a rapidly expanding human population – about 7.5 million people – in close contact with an ever-more vulnerable ecosystem.

Nick Aumen is an aquatic ecologist for the Everglades National Park, which protects the southern part of the original Everglades. In what used to be the northern part of the wetland, a huge agricultural area now covers more than 2,800 square kilometers.

Sugarcane being harvested on the property of U.S. Sugar Corporation, in the Everglades Agricultural Area

He says that in the Everglades Agricultural Area, crops can be grown almost year-round. "We're a major source of winter vegetables for much of the United States, and South Florida's also a major producer of sugar – of sugarcane, for the United States."

Producing sugarcane and other agricultural crops takes fertilizer – plant nutrients, such as phosphorus. Mark Kraus is an ecologist with the Everglades Foundation, a non-profit organization that supports Everglades restoration. He says that while phosphorus may be good for sugarcane, it has been devastating for the Everglades' plants, which need very low levels of nutrients.

"The Everglades are adapted to about 10 parts per billion of phosphorus," Kraus explains. "When you add a lot of additional phosphorus, it promotes the growth of other plants that aren't natural to those low-nutrient systems."

The Everglades is home to close to 70 threatened and endangered species, including the Florida panther (Puma concolor coryi)

Changes in water flow, nutrient pollution, and invasive species have all taken their toll on the Everglades, eliminating 90 percent of the wetland's former two million wading birds, and bringing almost 70 species – including panthers, alligators, and crocodiles – closer to extinction.

And as Nick Aumen explains, restoration projects have been expensive, and slow to show results. "The Everglades are the site of some of the largest and most expensive restoration projects in the world."

Aumen says that perhaps the biggest restoration effort was begun in 2000, and is projected to take as long as 35 years to complete and is estimated to cost as much as $18 billion.

A Great Egret (Ardea alba) wades in one of the Everglades' cyprus swamps

Recent restoration efforts have focused on energy-intensive engineering projects, including a controversial plan to pump water from Lake Okeechobee in and out of underground aquifers to control flooding and water availability.

But according to Mark Kraus, a proposed land deal could change all that. "This land purchase is going to allow us to restore the Everglades more quickly, in a much less engineered fashion, and in a much more sustainable way."

At the end of June, the state of Florida proposed to buy out U.S. Sugar Corporation, the largest sugarcane producer in the United States. The deal would take more than 750 square kilometers out of production, to be replaced by large water storage areas and artificial wetlands.

Mark Kraus says the deal presents a really exciting opportunity for Everglades restoration. "I have been involved in this Everglades restoration project for over 12 years now," says Kraus. "We always thought that the right way to do this would be to be able to acquire some agricultural land […] and provide these large areas of water storage and water cleansing."

The American Crocodile (Crocodylus acutus) inhabits the Everglades, as does the more common American Alligator

But the deal has its problems. Under agricultural cultivation, the area's peat soils have subsided by more than a meter, and getting water to flow south again will take some engineering.

What's more, U.S. Sugar's holdings are scattered throughout the region, so the state will have to negotiate land swaps with other sugarcane producers to recreate a continuous flow-way to the Everglades.

And under the current terms of the deal, no restoration projects will begin anytime soon: U.S. Sugar gets six years to transition out of farming.

Nick Aumen cautions that seeing environmental benefits from the more than 75,000 hectare buy-out could take even longer. A previous government land acquisition took ten years to start restoration in an area less than a third that size. "So it would not be surprising for us if this took as long, especially because it's a much larger land area."

But Aumen and Kraus agree that if the deal between the state of Florida and U.S. Sugar is successful, it could bring about unprecedented environmental benefits to one of the world's most beautiful – and threatened – ecosystems.