Keystone Species: Why are they Important?
A keystone species is a species that, if they were suddenly removed, would cause the entire ecosystem to change drastically. A keystone species can be anything from a predator to a major food source. A brief example of this would be the sea otter, and its protection of the kelp forests by eating the sea urchins that would otherwise destroy them, and thus drive out all the animals, fish, and other creatures living in the kelp forest.
I would like to bring up an animal that many of us like, though not because of its grace, but for its size: the African Elephant! The African Elephant is also a keystone species. These elephants destroy trees by eating all of their bark, thus preventing trees from reproducing and spreading out and getting dense, keeping their environment looking more like the savanna below, preventing the trees from hogging all the sunlight, allowing rich grasses to grow, which support the enormous herds of grazing animals, rather than the woodland on the right, which is what the savanna would eventually turn into, excepting the obviously deciduous trees! In turn, this keystone, or engineer, species, are preyed upon by lions and other ferocious animals.