Six key points for understanding the Everglades are:
The basic elements of the everglades are an unusual combination of geology (its porous limestone base), geography (on the border between tropical and temperate zones), climate (a monsoonal system with dry winters and soaking summers) and a surprising chemistry (very low concentrations of nutrients). While its limestone base began to form millions of years ago, the other elements which form the Everglades as we know it are only around 5000 years old.
Water is the key resource, which created and is the lifeblood of its diverse mixture of animals and plants. But the water is also shared with the people of South Florida, and the Everglades is usually on the losing end of this relationship.
The existence of the wild Everglades depends on the seasonality of water—a dry winter season and large amounts of rain, including tropical storms in the summer. Animals and plants depend on these fluctuations in the water level for their survival.
The Greater Everglades Ecosystem is a vast area, much more extensive than the National Park itself. It reaches 200 miles north of the Park and includes urban and agricultural areas, rock quarries, sugar mills and power plants. Its borders are under constant threat from urban sprawl.
Water levels vary by season and location. In the wet season, historically, water flowed from North to South—from Lake Okeechobee to Florida Bay—not as streams or rivers but as a slow shallow sheet (the “River of Grass”). Because the land is flat but not level, the major parts of the Everglades are interconnected. What happens in the north will have consequences many miles to the south.
The complexity and interconnectedness of the Everglades that make it so unique also make it unusually sensitive and fragile. Today, the water has been compartmentalized and cannot flow freely. Water is often too high or too low at the wrong times in the wrong places, and is restricted in it flow and fluctuation. Urban and agricultural development has contaminated its waters with phosphorus, nitrogen, sulfur, mercury and pesticides.