A species labeled as “keystone” is one that exerts strong control on the structure of a community. They do not use numerical influence, as dominant species do; instead, they use their ecological roles to gain significance. The American alligator shown above exemplifies a keystone species in several ways. As the top predators, they can regulate the numbers of prey species through predation. In addition, they alter their environment, which is beneficial to the other populations in the ecosystem as well. Removing the alligator from any habitat would yield drastic consequences on most of the biotic and abiotic factors of its vicinity.