savannah

Savannah is a broad term for a tropical or subtropical grassland ecosystem characterized by predominantly grasses with scattered trees and shrubs. It occurs in regions with hot climates and a pronounced seasonality of rainfall. In tropical savannas, rainfall typically ranges from about 500 to 1500 millimeters per year, concentrated in a distinct wet season, followed by a lengthy dry period. Fire and grazing are key ecological processes shaping savannas.

Flora is dominated by grasses, with trees such as acacias and baobabs adapted to drought and fire. Many trees shed leaves during the dry season to conserve water. Fire-resistant grasses and well-drained soils also help maintain open cover, which allows sunlit spaces for grasses to thrive.

Fauna includes large herbivores like wildebeest, zebras, antelopes, and elephants, alongside predators such as lions, cheetahs, and hyenas. Birds and insects are diverse, with many species adapted to seasonal resource pulses. The structure of savannas supports migrations and long-distance movements across landscapes.

Geographically, tropical savannas occur primarily in Africa, notably the Serengeti and Kruger regions, but similar ecosystems exist in South America (the Cerrado and Llanos) and Australia. Humans have long used savannas for grazing, pasture, and agriculture. Conversion, overgrazing, and fire suppression threaten species diversity and soil health; protected areas, sustainable grazing, and fire management are central to conservation.