american alligators live in freshwater environments, such as ponds, marshes, wetlands, rivers, lakes, and swamps, as well as in brackish water. when they construct alligator holes in the wetlands, they increase plant diversity and provide habitat for other animals during droughts. they are, therefore, considered an important species for maintaining ecological diversity in wetlands. farther west, in louisiana, heavy grazing by coypu and muskrat are causing severe damage to coastal wetlands. large alligators feed extensively on coypu, and provide a vital ecological service by reducing coypu numbers.