The long leaves of sawgrass, pointed with silica and as sharp as a saw blade, can grow to six feet or higher. Frequent fires hold back shrubs and favor the sawgrass and other marsh vegetation that grows around the ponds and sloughs. The flat Everglades Basin is sometimes flooded and, at other times, completely dry. Species in the Everglades have adapted to seasonal and long-term fluctuations in water levels and, in some parts of the system, to varying salinity levels. Alligators and other species, for example, have evolved so that they engineer their nesting areas instinctively depending on water levels.
Birds fly from one area to another as their food sources shift.
This amazing region, once home to vast quantities of life and still an important biological resource, has been designated an International Biosphere Reserve, a Wetland of International Significance, and a National Wilderness Area. Everglades National Park has been called the crown jewel of the National Park system-a major treasure. The Everglades watershed once covered almost a third of Florida, beginning just south of Orlando and ending more than 200 miles farther south in Florida Bay. Upstream from Lake Okeechobee, natural drainage created the channels of the Kissimmee River, Taylor Creek, and Fisheating Creek. Lake Okeechobee was a shallow depression about halfway down the watershed that collected water and passed much of it on to the Everglades.