What is the Savanna Biome?

Variable rainfall, grassland sprinkled with tall trees, and hardpan ground characterize the temperate Savanna biome. It can be found most famously in the plains of Africa, but parts of Florida, Brazil, Australia, and India belong to this biome as well. It is a mixture of prairie land and forest, but it has unique characteristics as well.

The temperature on the Savanna varies little from season to season, averaging a warm 68º F (20º C) over the year. Rainfall, though, varies drastically. The wet season lasts 6 - 8 months, dropping most of the area's 20 - 60 inches (60 - 150 cm) of rain in a short period of time. The hard ground's impermeability means the precipitation makes temporary puddles that only slowly feed ground water. In the dry winter months, drought overtakes the terrain, and water sources evaporate. Therefore, animals and plants have adapted to survive these exaggerated conditions. Some birds migrate to wetter areas, while some rodents go into a dormant state underground.

Trees of the Savanna have little biodiversity. Acacia and Baobob trees dominate the otherwise straight horizon line. These trees have flattened tops because grazers, like giraffes, nibble the lower branches. Other African mammals use the trees for shade and water. Elephants, zebras, water buffalo, ostriches, hyenas, warthogs, hippopotamus, gazelles, and leopards are famous members of this ecology. There is much biodiversity among herbivorous grazers and carnivorous predators.

The tropical Savanna biome is in a state of flux. Elephants could create grassland out of forest by trampling trees. Fire actually helps to preserve the Savanna. Dry grasses are easily ignited by lightning, and the swift burning fire sweeps the steppe. Birds and large animals have evolved to outrun the fire, while rodents burrow deep enough to withstand the heat. Even grasses store their water supply in their roots, rather than their blades, so they are not killed by a blaze. The fire moves too quickly to damage trees, so can safely germinate seeds of some species.

A savanna biome is characterized by a grassy plain with sparse tree coverage, typically found in tropical and subtropical regions. It experiences a distinct wet and dry season, with most rainfall occurring in a few months. This biome supports a diverse array of wildlife adapted to its unique climate and vegetation structure.

Savanna biomes are predominantly located near the equator, between the tropical rainforests and desert biomes. They cover approximately 20% of the Earth's land surface and are most extensive in Africa, but can also be found in South America, Australia, India, and the southern fringes of Asia.

The savanna climate is defined by a temperature range that typically does not fall below 18°C (64°F) and a distinct seasonal pattern with a wet season and a prolonged dry season. Annual rainfall is about 50-150 cm (20-59 inches), with most precipitation occurring during the wet season.

The savanna is dominated by grasses that can survive long periods of drought, interspersed with trees and shrubs that are often drought-resistant and fire-adapted. Acacia and baobab trees are iconic in African savannas, while South American savannas may feature palm trees and Australian savannas are home to eucalyptus.

Savannas are teeming with biodiversity, including large herbivores like elephants, giraffes, zebras, and wildebeests, which graze on the abundant grasses. Predators such as lions, cheetahs, and hyenas are also iconic savanna residents. Additionally, savannas support numerous bird species, insects, and smaller mammals that play crucial roles in the ecosystem.

Human activities such as agriculture, urbanization, and poaching have significant impacts on savanna biomes. Overgrazing and land conversion for farming can lead to soil degradation and loss of native vegetation. Poaching and hunting threaten the wildlife populations, while climate change is altering the delicate balance of these ecosystems.