This video shows how one species can affect an ecosystem. This concept may be one of the most important conservation notions to come up in the last century. This video tells how an apex predator or an animal that sits atop of the food chain can have a connecting effect on the entire ecosystem where it lives.
Watch how wolves, which were re-introduced in the Yellowstone National Park, help rivers come back to life. Deer species such as elks and wapiti have contributed immensely on why the flora around the rivers declined. The wolves which primarily target ailing and old elks help in controlling the local deer population. As a result, flora have re-grown and re-developed and increase the biodiversity in the area.