Beavers:Beavers are a classic example of an engineer keystone species. They build dams on rivers which create wetlands - beneficial for many plant and animal species.
Coral Reefs: Corals are another example of an engineer keystone species. They build large underwater structures (reefs) that provide habitat for a multitude of marine life.
Trophic Cascade: This term refers to changes in an ecosystem caused by the addition or removal of top predators (like wolves) or key engineers (like beavers). These changes can affect multiple levels of the food web.