Can you save my backyard? Fourteen-year-old Aaron Carter is a pop sensation with best-selling CDs like Oh Aaron and Another Earthquake! But he also helps conservationists spread the word to protect one of Earth's most invaluable resources. (Earth/life science: conservation/wetlands).

When Aaron Carter roams around his neighborhood, he sees houses, restaurants, and shopping malls. But part of the view also includes mangrove trees crowding the coast, tiny Key deer hiding among trees, and roseate terns wheeling overhead. Aaron lives in one of the planet's most diverse ecoregions--large geographical areas defined by features like type of soil, climate, and plant and animal communities: the Everglades and Florida Keys. "My family moved to the Keys because of its spectacular beauty," Aaron says.

Scientists would agree. "There's no system like this in the world," says biologist Tom Armentano of the Everglades National Park. "It's a wilderness despite the fact it shares common boundaries with densely populated areas." But this proximity between humans and nature has exacted a harsh toll on the once pristine environment: "I went on a research trip to a remote island in Florida Bay to check out the health of this really cool bird called a roseate spoonbill," says Aaron. "There used to be thousands of them in the Keys and Florida Bay, but huge changes in how water flows through the Everglades have really messed up their survival rate."

For thousands of years, South Florida was a 4-million-acre subtropical wetland (waterlogged area) teeming with dense flocks of wading birds, sea turtles, and crocodiles. Then pioneers flocked to the region in the 1800s, clearing it for farmlands. And in the late 1940s, to keep pace with the demands of a booming population, the U.S. government built levees (flood walls) and canal systems, which diverted water and drained marshes to create drier soils for farming (see diagram, p. 21). "But these changes disturbed the whole system and endangered its wildlife," says Debbie Harrison of World Wildlife Fund.

Today, the Everglades is one third of its historical size. And 600 of South Florida's plant and animal species are rare or threatened, according to the U.S. Fish and Wildlife Service. In addition, 68 species, including the Florida panther, snail kite, and Key deer are endangered (at risk of extinction). Today, conservationists are striving to devise strategies to deal with a growing environmental crisis. "This is a really special place in the world," says Aaron. "We need to make sure it's taken care of."

RIVER OF GRASS

Historically, during the rainy season from June to November, heavy rainwater would gush down the Kissimmee River to fill Lake Okeechobee. Water overflowed the southern rim to flood wide flat grassland. Known as the "river of grass," the Everglades--rarely more than 61 centimeters (2 feet) deep--slinked south. Its water drained up to 800 meters (0.5 mile) per day into the Florida Bay.

Along the way, the river filled sloughs, or deep marshes, submerged sawgrass prairies, and surrounded raised hammocks (hardwood islands). Under natural conditions, the season of flooding alternated with a long dry spell. Water levels receded and wading birds, raccoons, and alligators clamored to remaining pools of water to feast on trapped fish.

Today, most rainfall on the system's northern edge barely flows into the remaining patch of the Everglades. "It's pumped into canals, carried into developed areas and reservoirs, or dumped into the ocean," says Armentano. This deprives many species of the pools of water they depend on for food--especially critical during dry months.

The limited amount of freshwater that still flows through the Everglades and trickles into Florida Bay--an estuary (place where freshwater mixes with saltwater)--has caused an imbalance in the bay's salinity (salt levels). "One of the world's major shrimping grounds is in the Gulf of Mexico--it's a major food source for humans," Armentano says. Pink shrimp, for example, spend their post-larval stage, an immature phase of life, off the tip of the Everglades. "And they require the right conditions to live."

In addition, agricultural and industrial pollutants like mercury, phosphorous, and nitrogen have been found in water draining from the Everglades, causing many fish populations and sea grasses--a vital food source for the endangered manatee--to die off. The polluted runoff continues to flow south from Florida Bay into the Florida Keys.

Aaron Carter knows this water well. "I have always loved oceans and the marine environment," he says. And when he's not performing in concerts, he swims, kayaks, and snorkels in the Keys. "The Keys are home to the world's third-largest coral barrier reef and some of the world's greatest sunsets!" Many fish species live in this reef ecosystem. "My favorite is the blacktip reef shark," says Aaron. "It's fast, sleek, only takes what it needs, and rules the reef!" But water pollution is threatening the entire coral reef ecosystem.

RESCUE CALL

One critical piece in this complex survival puzzle is humans. South Florida's soaring human population depends on rain collected south of the Kissimmee River basin--including the Everglades--for drinking water. Of the estimated 100 to 165 cm (40 to 65 inches) that falls each year, nearly 100 percent evaporates, transpires (evaporates through plants), or is lost to run off. More troubling, the current water systems direct billions of tons of freshwater into the ocean each day. "A huge amount of that wasted water needs to be restored back into the Everglades, where it belongs--or we'll run out of water for humans, too," says Harrison.

Is the Everglades beyond rescue? No. Two years ago, the state and federal government appropriated $8 billion for the Comprehensive Everglades Restoration Plan. "It's a massive plan and actually involves 64 individual engineering projects to change how water is managed from Lake Okeechobee all the way down to Florida Bay," Armentano says. The undertaking will take decades to complete. In their attempt to figure out the delicate balance of human, animal, and environmental needs, scientists are using computer models to project figures like human population and water supply requirements for the year 2050. At the same time, they're doing fieldwork to gain clues about how the complex ecoregion once operated. "Hopefully, we'll be able to restore the Everglades closer to its natural pattern," says Armentano.

Saving the Everglades and South Florida ecoregion means a lot to Aaron Carter. "I'm always talking to my friends and family about how important it is to take care of it," he says. "Now I'm talking to kids across America: Let's take care of our waters and oceans."

MANATEE (Trichechus manatus)

(COOL FACT) Manatees are herbivores (plant eaters). They gather in coastal waters and rivers of South Florida to feed on aquatic plants like sea grasses. The gentle giant, also known as a sea cow, can spend eight hours a day eating between 4 to 9 percent of its body weight in food.

(REAL THREAT) This slow-moving mammal (animal that nurses young with milk) usually swims just beneath the water's surface. Due to increased boat traffic in South Florida, manatees have suffered infectious cuts from boat propellers or died from deadly collisions. Slow boat-speed areas have been established to help save manatees.

FLORIDA PANTHER (Felis concolor coryi)

(COOL FACT) The Florida panther sometimes just eats once a week. But the meal is huge--up to 14 kilograms (31 pounds) of meat, including white-tailed deer, wild hog, and raccoon. The large cat can also sleep 18 hours a day.

(REAL THREAT) Today, highways often crisscross the Florida panther's natural habitats. Since 1972, more than 40 panthers have been killed by vehicle collisions. To help the highly endangered panther--approximately 50 remain--cross the road, the government has built special underpasses (tunnels under highways) to help them stalk under it!

ROSEATE SPOONBILL (Ajaia ajaja)

(COOL FACT) The large pink and white bird has a unique flattened, spatula-like bill. When the spoonbill feeds, it doesn't look for food. It sweeps its sensitive 6-inch-long beak back and forth in usually shallow, muddy water to feel for food like small fish, crustaceans, and insects. Both parents feed their chicks with regurgitated food until babies are about 6 weeks old.

(REAL THREAT) Changes in the Everglades' water supply have shrunk the wading bird's feeding and nesting grounds. Their population has plummeted by 95 percent in the last 60 years.

EVERGLADES: THEN AND NOW

In the 1940s the U.S. government drained the Everglades to meet booming residential and agricultural demands. This drastically impacted native plant and animal life.

(A) For centuries, water flowed freely from the Kissimmee River and Lake Okeechobee (1) to Florida Bay (2). (B) Today, water is channeled through canals and rivers, either toward the sea (1) or to farmland on the lake's south border (2). Next, water is drained into one of three water conservation areas (3) and finally into Everglades National Park (4) and the sea (5). Today's National Park is the only area that truly resembles the historic Everglades.

The Everglades and South Florida ecoregion is part of this year's "Pennies for the Planet"--a program of World Wildlife Fund that educates youth about biodiversity and the concept of ecoregion-based conservation. To learn more and find out how you can get involved, visit: www.worldwildlife.org/windows/pennies