The species having greater influence on community characters in spite of being low numbers and biomass are called Keystone species.
The keystone species concept was put forward Robert T Paine to explain the relationship between Pisaster ochraceus (Starfish) and Mytilus californianus (Mussel).
Example of Keystone Species:
- Fig trees in a tropical rain forest support moneys, bats and birds. Any removal of these tress will adversely affect the animal population.
- Sea Otters are a keystone species of the kelp forest ecosystem. Kelp is home to hundreds of species like crabs, snails, sea urchins and geese etc that depend on kelp for food.
- Beavers, the mammalian architect construct dams and transforming streams into ponds, create new habitats for many plants and animal species.
- The flying fox is a key stone specie on tropical islands.It pollinates many of the plants, and is a key disperser of seeds.
- The prairie dog is a keystone species of the prairie ecosystem. They contribute to the lives of the other mammals by providing habitat and food.
- African elephants are the keystone species that maintain the entire savannah ecosystem. Elephants eat acacia and even if an acacia tree grows to a height of several feet, elephants are able to knock over the tree and uproot it.
- Some species of humming bird are keystone species in the Sonoran Desert of North America. Hummingbirds pollinate many varieties of native cactus and other plants.