Barcelona Field Studies Centre

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


Farmers forced to grow crops on marginal land

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

• Soil erosion

• Desertification


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

Click for graphic links:


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