Maintained
by...
Savanna vegetation is maintained by periodic
fires.The fires burn
back the forest vegetation, check the invasion of trees and
shrubs, and stimulate new grass growth. Savannas are also
influenced by large grazing mammals such as wildebeest and
zebra. Soil-determined savannas include the llanos of
Venezuela and the campos cerrados of Brazil. Grasses grow in the
soil above the crust; trees grow where roots, following cracks in
the crust, can reach deeper groundwater.