Sudanian Savanna

Category: Grassland, Tundra, and Human Biomes

Geographic Location: Sub-Saharan Africa.

Summary: A critically endangered mosaic of tropical dry forest, savanna, and grassland, this biome provides sustenance for a growing human population and is home to endangered animals such as the African wild dog.

The Sudanian savanna is a highly diverse ecosystem that extends across the African continent from the Ethiopian Highlands in the east to the North Atlantic Ocean in the west. This tropical biome is divided into two sub-segments, which are separated by the Cameroon Highlands in west-central Africa: the West Sudanian savanna, which runs from the Atlantic to eastern Nigeria; and the East Sudanian savanna that stretches from the Cameroon Highlands to the Ethiopian Highlands. During the dry season of December to February, local temperatures are generally 68–78 degrees F (20–25 degrees C); during the tropical or wet season, the temperature is 78–86 degrees F (22–30 degrees C).

Biodiversity

The Sudanian savanna is composed primarily of a mix of grasslands and woodlands. This mix features large deciduous trees such as Combretum, Terminalia and Acacia; long elephant grass (Pennisetum purpureum), and shrubs such as Combretum and Terminalia. The ecosystem is vast, stretching some 3,850 miles (6,200 kilometers) east to west, but it has been heavily fragmented and degraded. It is one of the World Wildlife Fund’s Global 200 priority ecoregions for conservation, and was designated as “critically endangered.”

The Sudanian savanna is home to a number of endangered animals, the populations of which have been significantly reduced by over-hunting and habitat destruction. The last population of black rhinoceros (Diceros bicornis) surviving within the Sudanian Savanna biome in Cameroon was declared extinct in 2011. The last sightings of the northern white rhinoceros (Ceratotherium simum) within this region—in the Democratic Republic of the Congo—were reported in 2007. Since then, the species has fundamentally extinct. Only three northern white rhinos survived as of the late-2010s. They were protected in a Kenyan game preserve. However, the last male died in 2018, leaving only two surviving females as of 2022.

Endangered and vulnerable species still occurring within the Sudanian savanna, according to the International Union for Conservation of Nature (IUCN) 2011 Red List of Threatened Species, include the Egyptian vulture (Neophron percnopterus), African elephant (Loxodonta africana), cheetah (Acinonyx jubatus), leopard (Panthera pardus), lion (Panthera leo), and the African wild dog (Lycaon pictus). Antelope species remain relatively stable in the region, with some exceptions such as the giant eland (Taurotragus derbianus) in Sudan and the roan antelope (Hippotragus equinus) in Sudan and Chad.

Among the birds found here are the East African crowned crane, ostrich, Kori bustard, and lilac breasted roller.

Environmental Impact

Residents of the Sudanian savanna depend heavily on their environment for fuel, food, medicine, income, and feed for livestock; these functions place great stress that is only mounting. The most acute threats to the biome are from the logging, charcoal production, farming including overgrazing by livestock, and wildfire. These factors have been particularly pronounced in the West Sudanian savanna, which is more densely populated. In part, these threats have been attributed to the local populations’ traditional lifestyle of seasonal cultivation and herding. However, factors affecting the behavior of the agro-pastoral population—such as rainfall, primary productivity, and the numbers of grazing animals—vary significantly. Therefore, it is difficult to attribute ecosystem change to any single factor.

In the East Sudanian savanna is a relatively undisturbed habitat outside the main protected areas. Approximately 7 percent of the West Sudanian savanna and 18 percent of the East Sudanian savanna consist of protected areas and national parks. Enforcement on the ground is often lacking and many parks struggle with the impact of civil unrest, political instability, and lack of resources. Due to very poor infrastructure in the region, wildlife-based tourism as a source of income is underdeveloped, with the exception of sport hunting in the Central African Republic.

The pressure on environmental resources exerted by the growing human population is amplified by the threat of climatic desiccation in the Sudanian Savanna biome. Recent years have shown higher than average rainfall, with some of the heaviest rains and extensive flooding occurring in the first two decades of the twentieth century. A flooding event in 2021 impacted 800,000 people and left more than 200,000 others homeless. Rainfall across the African continent is highly variable in space and time, but the general long-term trends in rainfall pattern point toward extreme drought following periods of increased precipitation in the Sudanian savanna—in other words, greater extremes.

Apart from potentially negative consequences for migratory wildlife, these global-warming-driven changes limit the ability of local habitats to recover from over-use. This is likely to result in increasing resource scarcity, from the direct effects of drought as well as indirect consequences such as soil erosion and leaching of nutrients.

To adapt to the changing environmental conditions and increasingly large-scale mechanized agricultural practices, water management strategies have changed in recent decades, with national and international programs diverting rivers and building dams. Although some of these developments are positive, providing water for irrigation and improving the efficiency of agriculture, other initiatives have resulted in severely damaged natural wetlands and flood plains. This has important implications for migratory wildlife, especially birds and fish, which often depend on these wetlands in the dry season—as well as for the human population, whose dependence on fishing and seasonal farming is tightly linked to the seasonal floods.

Bibliography

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International Business Publications (IBP). Sudan Ecology and Nature Protection Handbook. Washington, DC: International Business Publications, 2011.

“Northern White Rhino.” Fauna & Flora International, 2022, www.fauna-flora.org/species/northern-white-rhino/. Accessed 31 Aug. 2022.

Olson, David M. and Eric Dinerstein. “The Global 200: Priority Ecoregions For Global Conservation.” Annals of the Missouri Botanical Garden 89 (2002).

Shorrocks, Bryan. The Biology of African Savannahs (Biology of Habitats Series). New York: Oxford University Press, 2007.

“South Sudan Submerged.” NASA Earth Observatory, 6 Dec. 2021, earthobservatory.nasa.gov/images/149217/south-sudan-submerged. Accessed 31 Aug. 2022.

Wint, William and David Bourn. Livestock and Land-Use Surveys in Sub-Saharan Africa. Oxford, UK: Oxfam Professional, 1994.