Elephants are not the most common species in African grasslands. The grasslands contain scattered woody plants, but they are kept in check by the uprooting activities of elephants. Take away the elephants and the grasslands convert to forests or to shrublands. The newly growing forests support fewer species than the previous grassland. Given this, elephants can be defined as what type of species in this community

The elephants are the keystone species in this ecosystem.

Explanation:

The elephants' job is to knock down trees from time to time to get food from tall stock. This prevents the trees from overpopulating and allows shrub lands to stay in place. This is important as herbivores can continue to graze in large herds and carnivores can continue using the same hunting strategies with little to no push backs by trees.

This makes to elephants a keystone species as without them, the foundation species will decrease in population and create a whole different ecosystem with the trees as the new foundation species.