Prairie Dog: They contribute to the existence of the ecosystem in which it lives. They contribute to the soil and water quality in their plains ecosystem. their foraging retains water in the soil and forces fresh new grasses to continually grow. Young grasses have more nutrients for species such as bison and elk.
Elephants::Live in African grassland, also known as savannas. Without elephants grasslands would develop into forest . Elephants graze on trees such as a cacias above, preventing them from growing to maturity.
Sea otters: Important species in the kelp forest habitat. Sea urchins eat the kelp while the sea otters eat sea urchins. Preventing an overpopulation of urchins from destroying an ecosystem.
Hummingbirds: Are mostly in the Sonoran desert. Hummingbirds pollinate many native varieties of native cactus and other plants. Areas of the Sonoran desert with few hummingbirds, invanse species such as buffel grass have taken over the ecosystem.
Mountain Lion: Deer, rabbits and bird species in the ecosystem are at least partly controlled by the presence of the mountain lion. Feeding behavior or where they choose to make their nests and burrows, is a largely a reaction to the mountain lion's activity.
Sea Star: Mainly in tide pools, eat sea urchins, mussels and other shellfish that have no other natural predator. The concept of "keystone species" was developed by Dr.Robert Pain, who studied sea stars.