American alligators (Alligator mississippiensis) in the Everglades are unlike gators anywhere else in the United States. Gators here have adapted to the dry and rainy seasons by carving out small ponds in which to endure the dry season. These gator holes provide many other animals access to water when the marshes and swamps dry out, and are key in maintaining the biodiversity of fish, herps, and birds during the driest part of the year. These depressions may become deeper and wider with years of excavating, and eventually form large oases of water and trees scattered around the endless miles of marl marsh. Top down control as an apex predator combined with their impressive engineering abilities solidifies alligators as one of the most important keystone species in the whole Everglades. Their continued conservation is key to maintaining the biodiversity and ensuring function of the entire Everglades ecosystem.
At the southern end, in the Florida Bay, the fresh water of the Everglades meets the salt water of the Gulf of Mexico, creating a unique ecosystem for some species, like crocodiles, that like both.