Damage to fragile environments: farming and desertification in the Sahel

Management issues

Underlying Causes

Cause	Effect
Climatic	• Droughts are now more common • High temperatures cause a high rate of evapotranspiration • Rainfall is infrequent but intense, causing soil erosion
Over population	• Overgrazing • Overcultivation • Deforestation • Change in traditional farming practices. Nomads have adopted a more sedentary (settled) lifestyle with no change in traditional herding practices
Growth of Game Parks for tourism or of commercial farming interests. Cash crops take over the prime lands	• Reduced grazing land • Nomads have adopted a more sedentary (settled) lifestyle with no change in herding practices • Overgrazing, overcultivation and deforestation
Cattle represent wealth and confer social prestige	• Overgrazing

Photo credits. Sue White, Richard Wooldridge, Adam Dickinson, Dennis Holmes

The effects of overgrazing and the need to collect ever increasing quantities of fuel wood from the area surrounding a settlement

Specific Causes

Causes	Effects
Overgrazing	• Grass is unable to regrow • Soil erosion • Desertification
Overcultivation Farmers forced to grow crops on marginal land	• The continual use of the soil leads to loss of soil structure • Soil erosion • Desertification
Deforestation Trees are removed for fuel and to clear land for crops	• Trees are removed for fuel • Deforestation leads to soil erosion and: • reduced transpiration leads to less rainfall in the region • animal manure being used as fuel. It is no longer available to fertilise the soil, leading to reduced crop yields • reduced crop cover. Crops are destroyed by the heavy rain when it comes

Causes

Effects

Overgrazing

• Grass is unable to regrow

• Soil erosion

• Desertification

Overcultivation

Farmers forced to grow crops on marginal land

• The continual use of the soil leads to loss of soil structure

• Soil erosion

• Desertification

Deforestation

Trees are removed for fuel and to clear land for crops

• Trees are removed for fuel

• Deforestation leads to soil erosion and:

• reduced transpiration leads to less rainfall in the region

• animal manure being used as fuel. It is no longer available to fertilise the soil, leading to reduced crop yields
• reduced crop cover. Crops are destroyed by the heavy rain when it comes

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NASA AVHRR (Advanced Very High Resolution Radiometer) Image from 1986 shows the sharp boundary between the deserts to the North and the dense forests to the South on the Sahel