Ten years of research led by the University of South Florida has revealed that a monitor lizard should be regarded as an "ecosystem engineer," a rarity for reptiles. Tortoises and sea turtles are the only reptiles considered to be ecosystem engineers, a term used to describe organisms that have a great impact on their environment based on their ability to create, modify, maintain or destroy a habitat. Sean Doody, assistant professor and graduate director of integrative biology at the USF St. Petersburg campus, discovered that while a related species is considered invasive in the United States, in Australia, small animal communities rely on the monitor lizards' burrow system, called a warren, using it as a habitat, a place to forage for food and nesting.