The trouble with keystone species

Each species plays a role - it performs a job - in its ecosystem. If it goes extinct, the ecosystem changes irreversibly. For ecosystems which we don't know well (the vast majority), such changes are unpredictable. Even worse, some species are fundamental to the functioning of their ecosystem.

These are called keystone species and include well-known ones such as jaguars, beavers, and some sharks, as well as species easily overlooked, such as fig trees, krill, mangrove crabs, gopher tortoises, and prairie dogs. Because of its critical function, the loss of a keystone species results in a fundamental disruption of the ecosystem it controls. Unfortunately, identifying a keystone species requires extensive research - and for most ecosystems, we simply don't know it. So disrupting ecosystems is a pretty bad idea.