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Sub-Saharan Africa

Map of Sub-Saharan Africa Habitats
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Sub-Saharan Africa experiences several different climate regimes. The most common are the tropical wet and dry, tropical wet, and tropical dry. Many areas of the continent are subject to recurring droughts.

In the tropical wet-and-dry climate, there is a distinct dry season during the winter months. During the dry season, very little rainfall occurs and droughts are common. Rainfall occurs during the remainder of the year. Rainfall in the tropical wet-and-dry climate can be highly irregular, varying tremendously from one year to the next. In this climate regime, destructive floods can be followed by severe drought. Vegetation in the tropical wet-and-dry regions of Sub-Saharan Africa is mainly tall savanna grass and low, drought resistant deciduous trees.

Photograph of Tropical Wet and Dry Climate (Savanna)
Isolated trees and tall grasses typify the African savanna, one of the habitats found in tropical wet-and-dry climate regions. (Photograph copyright Chuck Bargeron, The University of Georgia, ForestryImages.org)

The tropical wet climate regime affects much of western central Africa. In this region, trade winds from the northern and southern hemisphere meet. As the winds meet, air is forced upward. As the air rises, moisture condenses and towering rain-producing clouds, also called cumulonimbus clouds, form. These cumulonimbus clouds produce heavy rainfall. The heavy rainfall and warm temperatures provide the conditions necessary for the growth of tropical rain forest.

Tropical dry climates are characterized by very little rainfall and high temperatures. Even when rain does fall, the region remains dry because the high temperatures cause high rates of evaporation. The tropical dry climate can be divided into the semi-arid and arid climates. The semi-arid regions receive more rainfall than the arid regions. Vegetation in the semi-arid region is mostly short grass prairie. Arid environments receive very little rainfall and are characterized as deserts.

photograph of cumulonimbus clouds Towering clouds, called cumulonimbus by meteorologists, deliver year-round rains to areas with a tropical wet climate. (Photograph copyright Dr. John Day, “Cloudman”)

Tropical Rain Forest
Photograph of Tropical Wet Climate (Rainforest)
This habitat occurs where temperatures are high year-round, and where precipitation is very high. Some regions supporting rain forest have one or more relatively dry months (with less than 100 mm of rain), but true droughts are extremely rare. In rain forests that experience two or three drier months, some of the trees may drop their leaves for several weeks. These forests are called semi-deciduous rain forests. However, many rain forests are rainy all year long—total annual rainfall can reach 6 meters!

Rain forests are complex, with as many as five distinct vegetation layers from top to bottom. The tallest trees may be over 60 m tall with tops as wide as a football field. Large woody vines, called lianas, are common in many rain forests. Although tropical rain forests receive 12 hours of sunlight daily, less than 2% of that sunlight ever reaches the ground. Epiphytes (plants growing on the leaves of other plants) are smaller plants that use the tall trees as a way to reach the light near the top of the forest.

Rain forests have higher plant diversity than any other habitat on earth. There can be hundreds of species of trees even in a small area. Animal diversity is also highest in this habitat, especially among insects, birds, reptiles and amphibians. Adaptations for living in trees are common and include the abilities to climb, jump, swing, glide, and hang from branches. Mammals common to rain forests are apes, monkeys, bats, tree shrews, squirrels, cavies, sloths, pangolins, forest deer and antelope, civets, and cats.

Tropical rain forests feature dense vegetation that thrives in heavy rainfall and year-round warmth. (Photograph 1230014 copyright Gerard D. Hertel, West Chester University, ForestryImages.org)

Desert
Photograph of Tropical Dry Climate (Desert)
Desert habitats occur in both north and south Africa. These parts of Africa receive the least precipitation. Daily temperature variation is more extreme in dry climates, thus it is common for deserts to experience very hot days and very cool nights.

Desert often has very little vegetation. Where it does occur, vegetation typically consists of well-spaced shrubs, succulents and cactus. The leaves of desert shrubs are small and waxy to prevent water loss, and shiny to reflect sunlight and prevent overheating.

Succulents and cactus have thick fleshy leaves or stems that can store water. Spines protect these plants from herbivores.

Desert animals exhibit many adaptations to drought, including the ability to live without drinking water (their metabolic water is obtained entirely from plants). Lizards, snakes, and rodents are well adapted to dry environments. Many species are active only at night (or early and late in the day in diurnal species), when the humidity is higher and the temperature lower. Camels are one of the few large mammals that are well adapted to desert.

Without irrigation, agriculture is not possible in deserts, thus very few desert plants are cultivated (prickly pears and agaves only recently). Because of this, many desert peoples are nomadic, and a few large mammals of the desert (like camels) were domesticated for transportation.

Mediterranean Vegetation

A narrow region of Mediterranean vegetation occurs along the southern coast of Africa. Here, summers are warm and dry, and winters are cool and rainy. Fog, produced by the cold ocean water offshore, is common and moderates summer temperatures. Total annual precipitation ranges between 15 and 40 inches per year. The Mediterranean shrublands of South Africa are called the “fynbos”.

Throughout the world, the Mediterranean habitat is characterized by shrubs. Plants are adapted to withstand drought, and many are adapted to regrow or sprout quickly after fire. In most regions these shrubs are evergreen and have small, leathery leaves. Many typical shrubs have strong aromas (for example, sage, rosemary, thyme, and oregano) and contain highly flammable oils. Certain trees, like live oaks and olive trees, are also characteristic of Mediterranean climates.

Short Grass Prairie

Both of the major African deserts are bordered by areas of short grass prairie. There is too little precipitation in steppe for trees to grow, except near rivers. Grasses grow in bunches and have extensive root systems. Agriculture is difficult in these arid grasslands and humans in these areas are commonly nomadic herders of goats or cattle.

Desert habitats receive so little rain that vegetation is scarce. (Photograph copyright Dina Cheal, The Africa Guide)

Savannas

This habitat occurs where there is a 6 to 8 month wet summer season and a dry winter season. Some savannas get as little as 10 inches of rain annually while others can get as much as 50 inches. The dry season is marked by months of drought and lightening frequently ignites the brown, dry grasses that cover the savanna. Without the yearly period of drought and fire, some scientists believe that tropical savannas would eventually change into tropical forests.

The tropical savanna is characterized by tall grasses and occasional trees. Some grasses grow 6 to 9 feet tall. Where trees are more common, savanna may be referred to as wooded savanna. In savannas, trees have long tap roots to reach the deep water table, thick bark for resistance to annual fires (thus palms are prominent in many areas), deciduousness to avoid moisture loss during the dry season, and use of the trunk as a water-storage organ. The acacia and baobab trees are common in African savannas.
photograph of an acacia tree
The acacia is one common tree of the savanna. (Photograph courtesy US Fish and Wildlife Service)

photographs of an elephant, a rhino, giraffes, and lions
Large grazing mammals are successful in savannas of the lush growth of grasses during the rainy season. The African savanna is home to wildebeest, warthogs, elephants, zebras, rhinos, gazelles, giraffes, hyenas, cheetahs, lions, leopards, ostriches, and baboons. Most birds and many of the large mammals migrate during the dry season in search of water. Human populations are large in African savanna, where cattle and goats are raised. Thus one of the most significant human effects is overgrazing.

Tropical Woodlands

This habitat occurs where temperatures are high all year, but there is a better defined dry season than in the tropical rain forest. Many evergreen tree species of the rain forest become deciduous in this zone. These forests are shorter than rain forests; trees may reach 10-30m and trees are more widely spaced. Trees have thicker bark (antifire adaptation), thicker and smaller leaves (antidesiccation adaptation), thorns (antiherbivore adaptation), and longer roots (to reach deeper water table). Lianas are much less common and epiphytes are drought-resistant plants such as orchids, bromeliads, and cacti. With more spaces between trees, larger mammals are more prominent in this environment.

The high productivity during the rainy season, coupled with relief from rains during the dry season, makes this a favorable environment for humans and domestic stock, so much of the zone has been cleared and developed for pastureland as well as agriculture.

Animals living on the savnna include elephants, rhinos, giraffes, and lions. (Photograph courtesy US Fish and Wildlife Service)

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	PES » Global Warming » Information Center » Sub-Saharan Africa
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	Sub-Saharan Africa experiences several different climate regimes. The most common are the tropical wet and dry, tropical wet, and tropical dry. Many areas of the continent are subject to recurring droughts. In the tropical wet-and-dry climate, there is a distinct dry season during the winter months. During the dry season, very little rainfall occurs and droughts are common. Rainfall occurs during the remainder of the year. Rainfall in the tropical wet-and-dry climate can be highly irregular, varying tremendously from one year to the next. In this climate regime, destructive floods can be followed by severe drought. Vegetation in the tropical wet-and-dry regions of Sub-Saharan Africa is mainly tall savanna grass and low, drought resistant deciduous trees.
			Isolated trees and tall grasses typify the African savanna, one of the habitats found in tropical wet-and-dry climate regions. (Photograph copyright Chuck Bargeron, The University of Georgia, ForestryImages.org)
	The tropical wet climate regime affects much of western central Africa. In this region, trade winds from the northern and southern hemisphere meet. As the winds meet, air is forced upward. As the air rises, moisture condenses and towering rain-producing clouds, also called cumulonimbus clouds, form. These cumulonimbus clouds produce heavy rainfall. The heavy rainfall and warm temperatures provide the conditions necessary for the growth of tropical rain forest. Tropical dry climates are characterized by very little rainfall and high temperatures. Even when rain does fall, the region remains dry because the high temperatures cause high rates of evaporation. The tropical dry climate can be divided into the semi-arid and arid climates. The semi-arid regions receive more rainfall than the arid regions. Vegetation in the semi-arid region is mostly short grass prairie. Arid environments receive very little rainfall and are characterized as deserts.		Towering clouds, called cumulonimbus by meteorologists, deliver year-round rains to areas with a tropical wet climate. (Photograph copyright Dr. John Day, “Cloudman”)
	Tropical Rain Forest This habitat occurs where temperatures are high year-round, and where precipitation is very high. Some regions supporting rain forest have one or more relatively dry months (with less than 100 mm of rain), but true droughts are extremely rare. In rain forests that experience two or three drier months, some of the trees may drop their leaves for several weeks. These forests are called semi-deciduous rain forests. However, many rain forests are rainy all year long—total annual rainfall can reach 6 meters! Rain forests are complex, with as many as five distinct vegetation layers from top to bottom. The tallest trees may be over 60 m tall with tops as wide as a football field. Large woody vines, called lianas, are common in many rain forests. Although tropical rain forests receive 12 hours of sunlight daily, less than 2% of that sunlight ever reaches the ground. Epiphytes (plants growing on the leaves of other plants) are smaller plants that use the tall trees as a way to reach the light near the top of the forest. Rain forests have higher plant diversity than any other habitat on earth. There can be hundreds of species of trees even in a small area. Animal diversity is also highest in this habitat, especially among insects, birds, reptiles and amphibians. Adaptations for living in trees are common and include the abilities to climb, jump, swing, glide, and hang from branches. Mammals common to rain forests are apes, monkeys, bats, tree shrews, squirrels, cavies, sloths, pangolins, forest deer and antelope, civets, and cats.		Tropical rain forests feature dense vegetation that thrives in heavy rainfall and year-round warmth. (Photograph 1230014 copyright Gerard D. Hertel, West Chester University, ForestryImages.org)
	Desert Desert habitats occur in both north and south Africa. These parts of Africa receive the least precipitation. Daily temperature variation is more extreme in dry climates, thus it is common for deserts to experience very hot days and very cool nights. Desert often has very little vegetation. Where it does occur, vegetation typically consists of well-spaced shrubs, succulents and cactus. The leaves of desert shrubs are small and waxy to prevent water loss, and shiny to reflect sunlight and prevent overheating. Succulents and cactus have thick fleshy leaves or stems that can store water. Spines protect these plants from herbivores. Desert animals exhibit many adaptations to drought, including the ability to live without drinking water (their metabolic water is obtained entirely from plants). Lizards, snakes, and rodents are well adapted to dry environments. Many species are active only at night (or early and late in the day in diurnal species), when the humidity is higher and the temperature lower. Camels are one of the few large mammals that are well adapted to desert. Without irrigation, agriculture is not possible in deserts, thus very few desert plants are cultivated (prickly pears and agaves only recently). Because of this, many desert peoples are nomadic, and a few large mammals of the desert (like camels) were domesticated for transportation. Mediterranean Vegetation A narrow region of Mediterranean vegetation occurs along the southern coast of Africa. Here, summers are warm and dry, and winters are cool and rainy. Fog, produced by the cold ocean water offshore, is common and moderates summer temperatures. Total annual precipitation ranges between 15 and 40 inches per year. The Mediterranean shrublands of South Africa are called the “fynbos”. Throughout the world, the Mediterranean habitat is characterized by shrubs. Plants are adapted to withstand drought, and many are adapted to regrow or sprout quickly after fire. In most regions these shrubs are evergreen and have small, leathery leaves. Many typical shrubs have strong aromas (for example, sage, rosemary, thyme, and oregano) and contain highly flammable oils. Certain trees, like live oaks and olive trees, are also characteristic of Mediterranean climates. Short Grass Prairie Both of the major African deserts are bordered by areas of short grass prairie. There is too little precipitation in steppe for trees to grow, except near rivers. Grasses grow in bunches and have extensive root systems. Agriculture is difficult in these arid grasslands and humans in these areas are commonly nomadic herders of goats or cattle.		Desert habitats receive so little rain that vegetation is scarce. (Photograph copyright Dina Cheal, The Africa Guide)
	Savannas This habitat occurs where there is a 6 to 8 month wet summer season and a dry winter season. Some savannas get as little as 10 inches of rain annually while others can get as much as 50 inches. The dry season is marked by months of drought and lightening frequently ignites the brown, dry grasses that cover the savanna. Without the yearly period of drought and fire, some scientists believe that tropical savannas would eventually change into tropical forests. The tropical savanna is characterized by tall grasses and occasional trees. Some grasses grow 6 to 9 feet tall. Where trees are more common, savanna may be referred to as wooded savanna. In savannas, trees have long tap roots to reach the deep water table, thick bark for resistance to annual fires (thus palms are prominent in many areas), deciduousness to avoid moisture loss during the dry season, and use of the trunk as a water-storage organ. The acacia and baobab trees are common in African savannas.		The acacia is one common tree of the savanna. (Photograph courtesy US Fish and Wildlife Service)
	Large grazing mammals are successful in savannas of the lush growth of grasses during the rainy season. The African savanna is home to wildebeest, warthogs, elephants, zebras, rhinos, gazelles, giraffes, hyenas, cheetahs, lions, leopards, ostriches, and baboons. Most birds and many of the large mammals migrate during the dry season in search of water. Human populations are large in African savanna, where cattle and goats are raised. Thus one of the most significant human effects is overgrazing. Tropical Woodlands This habitat occurs where temperatures are high all year, but there is a better defined dry season than in the tropical rain forest. Many evergreen tree species of the rain forest become deciduous in this zone. These forests are shorter than rain forests; trees may reach 10-30m and trees are more widely spaced. Trees have thicker bark (antifire adaptation), thicker and smaller leaves (antidesiccation adaptation), thorns (antiherbivore adaptation), and longer roots (to reach deeper water table). Lianas are much less common and epiphytes are drought-resistant plants such as orchids, bromeliads, and cacti. With more spaces between trees, larger mammals are more prominent in this environment. The high productivity during the rainy season, coupled with relief from rains during the dry season, makes this a favorable environment for humans and domestic stock, so much of the zone has been cleared and developed for pastureland as well as agriculture.		Animals living on the savnna include elephants, rhinos, giraffes, and lions. (Photograph courtesy US Fish and Wildlife Service)
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