What is the starfish experiment?

When starfish were removed from their environment, the species richness of that area went down. This was because the starfish ate the mussels, and when the starfish were removed, the mussels became abundant and preyed on many of the other species.

This experiment showed that the starfish were a keystone species. A keystone species is a species that has a low biomass but a large impact on the community they are living in.