The Everglades is a massive and unique subtropical wetland ecosystem covering a vast area of South Florida. This region is a complex mosaic of freshwater marshes, sawgrass prairies, and mangrove forests. Its sheer scale and biological diversity have earned it global recognition as a natural wonder, playing a profound role in the regional environment.
It is Not a Swamp, But a River of Grass
The common misconception that the Everglades is a swamp overlooks its defining hydrological feature: a very slow-moving body of water. This ecosystem is best described as a “River of Grass,” a phrase coined by writer Marjory Stoneman Douglas that captures its true nature. The water originates primarily from Lake Okeechobee and flows southward toward Florida Bay in a broad sheet. This sheet flow is often 50 to 60 miles wide but only a few inches deep, moving over a nearly flat limestone base. The vast expanse is dominated by sawgrass, a tall, sharp-edged sedge that provides the “grass” element of the river.
The Only Place Where Crocodiles and Alligators Coexist
The Everglades is the only place in the world where both American alligators and American crocodiles live together in the wild. American alligators generally prefer freshwater environments, such as the northern marsh areas, while American crocodiles thrive in brackish and saltwater. The American crocodile possesses a specialized lingual salt gland that allows it to excrete excess salt. This gland enables the crocodile to survive in the coastal, saline waters of Florida Bay and the Everglades’ mangrove estuaries. Alligators lack this developed salt gland, confining them mostly to freshwater, but the gradient of fresh to salt water creates a unique zone where both species can successfully coexist.
Built on a Foundation of Ancient Marine Life
The entire foundation of the Everglades landscape is a vast layer of porous limestone, which is surprising considering its current freshwater character. This rock formed over millions of years from the compressed calcium carbonate remains of ancient marine organisms, such as shells and coral reefs, when the region was submerged beneath the sea. This limestone bedrock, which includes the Miami Limestone formation, is highly permeable and acts like a sponge. Resting atop this rock is a thin layer of soil, primarily peat and marl, which formed from centuries of decaying organic matter.
A Water Source for Millions of People
The Everglades is a functional provider of drinking water for a massive metropolitan area. The slow flow of water across the landscape is the primary mechanism for recharging the Biscayne Aquifer, which lies just beneath the surface. This aquifer is the main source of fresh drinking water for counties like Miami-Dade, Broward, and Palm Beach. The wetlands act as a natural filtration system, purifying the water as it percolates down into the aquifer. Maintaining the natural flow of the Everglades is vital, as reduced freshwater flow can lead to saltwater intrusion into the aquifer.
Designated as Three International Sites
The global importance of the Everglades ecosystem is recognized by its designation as three separate international sites. The area is a UNESCO World Heritage Site, which acknowledges its outstanding universal value as a natural treasure. It is also an International Biosphere Reserve, a recognition that highlights its role as a model for sustainable development and conservation. Finally, the Everglades is designated as a Wetland of International Importance, known as a Ramsar Site.