Keystone species are considered the "cornerstone" of an ecosystem, as they have a disproportionately large impact on the health and balance of the environment. They are often predators, such as wolves or sharks, that help to regulate the populations of other species and keep the ecosystem in check. Without these keystone species, the entire ecosystem could collapse, as the balance of predator and prey would be thrown off. In addition to regulating populations, keystone species can also provide important ecosystem services, such as pollination, seed dispersal, and nutrient cycling.
