Grasslands and savannas both belong to the grassland biome. While the difference in name may seem insignificant at first, these two environments are dramatically different, with different climates, geographies and ecologies. Savannas also are called “tropical grasslands” and other grasslands are simply called “temperate grasslands.”
Africa immediately springs to many people’s minds when discussing grasslands and savannas, but both occur throughout the world. A savanna requires a warm, wet climate with a hot dry season, which allows for a cycle of rampant new growth and rapid burn off. Slightly less than 50 percent of Africa is covered by savannas, but they also are found in India, Australia and South America. Grasslands require a slightly less dramatic climate and consequently can be found across many disparate sections of the planet, including Russia, Africa, North America, South America and Eastern Europe.
The soils of savannas and grasslands could not be more different. Savanna soil is extremely absorbent and drains quickly. Grasslands have thick, dark soil that is rich in nutrients. The fires that occur annually on savannas between October and January constantly burn off dried and dead vegetation. These fires cleanse the savannas every year, so savannas have only a light layer of humus, which is the organic part of soil that is created by decomposing vegetation and animal life. Grasslands, however, do not experience these fires, so the soil has a thick layer of humus that sustains continuous new growth by the natural breakdown of the previous season’s vegetation.
While grasslands are found in many regions of the world, there are some general patterns to their weather. Grasslands are drier and warmer than savannas and receive less rainfall annually. The average grassland experiences a dry season and a wet season with dramatic fluctuations between the two. The average grassland, regardless of geographic location, receives an average rainfall of 10 to 30 inches per year. Savannas have a wet season for at least seven months followed by an extremely hot dry season. The exact time of year depends on the location of the savanna, but most savannas receive 30 to 40 inches of rainfall annually. Thunderstorms are common during the dry season.
Grasslands are true to their name, with several strains of grass covering the vast plains. These perennial grasses use their complex root systems to reduce loose dirt, lock in moisture and reduce temperatures during torrid summer months. Temperate grasslands are largely vacant of trees and shrubbery. Savannas, on the other hand, are home to many varieties of trees, grasses and other plants. There is debate over whether savannas belong in the grassland or forest biome given their abundance of deciduous trees. Grouped-tree grasslands, a type of savanna found in parts of Kenya, Uganda and Tanzania, are characterized by the clumps of trees that grow atop termite mounds.