American alligators have proven to be an important part of the environment, and therefor, are considered by many to be a "keystone" species. Not only do they control populations of prey species, they also create peat and "alligator holes" which are invaluable to other species. Red-bellied turtles, for example, incubates its own eggs in old alligator nests. Alligators also are good indicators of environmental factors, such as toxin levels. Increased levels of mercury have been found in recent blood samples.

Ecosystem Impact: creates habitat; keystone species