African Biomes

by

Anthony R.E. Sinclair, Rene L. Beyers

• LAST REVIEWED: 30 August 2021
• LAST MODIFIED: 29 September 2014
• DOI: 10.1093/obo/9780199830060-0112

Introduction

Africa has a great diversity of environmental conditions. It is bisected by the equator so that the seasons are six months out of phase north and south of it. There are tropical forests on the west side as well as in the center of the continent. In roughly concentric rings out from the forest, there are progressively drier vegetation types from woodland, savanna, and grassland to desert. There are several major rivers flowing north, west, and east. Africa has also been the center of evolution of many large mammal groups. It has a high diversity of birds and insects. It is also the origin of the human species, and humans have influenced and modified the landscape for hundreds of thousands of years. Humans evolved there over the past four million years. The environment and the biomes that result from it in turn shaped the evolution of humans. Over the Pleistocene (past two million years), the environment swung from warm and wet to cool and dry several times, and consequently the biomes changed in extent from continuous forest (that stretched from the Atlantic to the Indian Ocean) to dry savanna and desert with only small patches of forest in West and Central Africa. These changes that were connected to the ice ages of temperate regions affected human populations. In the past millennium, human numbers have increased and migrations have moved peoples southward through the forests of Central Africa and into eastern and southern Africa. These movements have modified the biomes through grazing pressures on grasslands and agriculture in savanna. In the 20th century, forests were modified through deforestation. Wildlife conservation and ecotourism are prominent in Africa. There are several large protected areas especially in eastern and southern savanna Africa, with some less-known areas of forest reserves. Scientific studies on these protected areas over several decades describe the biology and ecosystem dynamics perhaps better than any other continent. There are scientific syntheses on the Kruger National Park, South Africa, and the Serengeti National Park, Tanzania. Both highlight how the whole ecosystem changes over time with climate change, human population increases, disease outbreaks, and other disturbances. The following sections first cover the vegetation types that are called Biomes; two abiotic environmental factors, climate and fire (Climate Variability and Patterns of Drought and Fire); prominent animal groups characteristic of Africa (Large Mammals, Primates, and Birds); dominant processes such as herbivory, predation, niche partitioning, facilitation, and migration (Herbivory, Predators and Predation, Niche Partitioning, Facilitation, and Migrations); and finally the expansion of human impacts on biomes and the related aspects of traditional livelihoods and conservation (Traditional Human Livelihoods and Conservation). Social and political history also modify human impacts but are not covered in this review.

Biomes

Africa’s rich diversity in habitats and biological life is reflected in the high number of terrestrial biomes that it contains: nine out of fourteen globally (Olson, et al. 2001). A biome can be defined as a region sharing similar habitats or vegetation types at a global scale. Biomes have similar climatic conditions, mainly temperature and precipitation. Their location in Africa is linked to six climatic zones, which are described in UNEP 2008. Biomes are classified within biogeographic realms. Udvardy 1975 recognizes eight global biogeographic realms, of which two are present in Africa: the Palearctic in the northern third and the Afro-tropical in the rest of the continent. There is no exact agreement as to what constitutes a particular biome, and several classifications exist; for examples for Africa, compare UNEP 2008; Adams, et al. 1996; and Burgess, et al. 2004. Here, nine terrestrial biomes are described following Burgess, et al. 2004. Within biomes, smaller units of distinct ecosystems can be distinguished. Ecoregions are units of land with distinct animal and plant communities nested within biomes and biogeographic realms. They were developed as tools for conservation. Burgess, et al. 2004 identifies 119 ecoregions of Africa in the World Wildlife Fund’s (WWF) global diversity map. A standard reference for the classification of vegetation in Africa is the White 1983 vegetation map, which recognizes seventeen major vegetation types based on structural characteristics; this has formed the basis for WWF’s ecoregions. An alternative classification is presented in Sayre, et al. 2013, which uses a modeling approach to produce a map with the potential distribution of 126 “vegetation macrogroups.”

• Adams, W. M., A. Goudie, and A. Orme, eds. 1996. The physical geography of Africa. Oxford: Oxford Univ. Press.

  Overview of the physical environment of Africa, including a chapter on the biogeography (pp. 161–172) and a chapter for each of the biomes recognized in this work (pp. 173–325).

• Burgess, N., J. A. d’Amico, E. Underwood, et al. 2004. Terrestrial ecoregions of Africa and Madagascar: A conservation assessment. Washington, DC: Island.

  This book presents the ecoregion classification of Africa. It describes 119 ecoregions, their distinctive biological features, current status, and threats. Besides an explanation of the process and criteria behind the classification, there are chapters on the ranking of ecoregions according to their biological value, the use of ecoregions as a tool for conservation, setting priorities, and planning for conservation.

• Olson, D. M., E. Dinerstein, E. D. Wikramanayake, et al. 2001. Terrestrial ecoregions of the world: A new map of life on Earth. BioScience 51.11: 933–938.

  DOI: 10.1641/0006-3568(2001)051[0933:TEOTWA]2.0.CO;2

  This article precedes the book Burgess, et al. 2004 on ecoregions and explains the methods used to develop the global terrestrial ecoregion classification lead by WWF. Descriptions of each ecoregion in the world can be found at WWF’s biomes.

• Sayre, R., P. Comer, J. Hak, et al. 2013. A new map of standardized terrestrial ecosystems of Africa. Washington, DC: Association of American Geographers.

  The authors of this paper model the potential distribution of 126 vegetation macrogroups using a Classification and Regression Tree (CART) analysis. Input datasets include landforms, surficial lithology, bioclimates, thermotypes, ombrotypes (Phytogeographic regions), and point samples. Unique for this study is the fine resolution (90 m) at which ecosystem distribution was predicted and the standardized continent-wide approach to ecosystem classification.

• Udvardy, M. D. F. 1975. A classification of the biogeographical provinces of the world. IUCN Occasional Paper 18. Morges, Switzerland: International Union of Conservation of Nature and Natural Resources.

  Classification of the biological environment on earth in biogeographic provinces within biogeographic realms. Two realms and thirty-one provinces are recognized in Africa. Contains a description of each realm and black and white maps of biogeographic provinces.

• UNEP. 2008. Africa: Atlas of our changing environment. Nairobi, Kenya: UNEP.

  Contains maps and descriptions of the African physical, human, and biological environment. Several environmental case studies are presented. For each country a geographic and environmental profile is given, including threats to biodiversity.

• White, F. 1983. The vegetation of Africa: A descriptive memoir to accompany the UNESCO/AETFAT/UNSO vegetation map of Africa. Paris: UNESCO.

  This is a standard reference for mapping the vegetation of Africa and providing a framework for also more recent classifications. White classifies the vegetation based on physiognomy (appearance of the vegetation) and he recognizes sixteen main types, which include anthropic landscapes. These vegetation types occur within twenty phytochoria, or phytogeographic (floristic), areas across the continent and in Malagasy. A detailed analysis of vegetation regions and subregions is presented with according maps. Contains three plates, 1:5,000,000.