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

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

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