- Process by which land becomes desert-like. - Process by which land becomes drier and degraded, as a result of climate change and/or human activities.
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What is a desert fringe?
- The 'buffer' between desert and 'normal' land. - Supports greater biodiversity and larger plants, than in the middle of the desert.
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Soil erosion
- Soil that is exposed is easily removed by wind or water. - Nutrients in the soil are lost, making sound unproductive. - Eventually the ground becomes sandy, dusty, stony or just bare rock.
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Climate change - rainfall
- Climate change is expected to reduce rainfall in areas that are already quite dry. - Less rain = less water available for plant growth = plants die. - Plant roots hold soil together, so if plants die, the soil is easily eroded.
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Climate change - temperatures
- Global temperatures are expected to increase. - High temp.s = more water evaporated from land and plants = soil becomes drier = plants die = roots no longer hold soil together.
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Human activities - removal of fuel wood
- Many people in arid (dry) areas rely on wood for fuel for cooking. - Removal of trees leaves soil exposed so it's more easily eroded.
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Human activities - overgrazing
- Too many cattle or sheep eat the plants faster than they can re-grow = more soil erosion because plants no longer hold soil together. - Trampling by animals also erodes soil.
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Human activities - over-cultivation
- If crops are planted in same area continually, all nutrients in soil get used up - plants can no longer be grown in those soils and, without plants, soil erosion increases.
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Human activities - population growth
- Puts pressure on land, leading to more deforestation (for firewood), more overgrazing and more over-cultivation.
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Causes specific to Sahel desert
- Global warming. - Over crowding. - 50 million vulnerable people live there. - Lack of education (farming practices). - Little money and tech. available in Sahel countries to help adapt.-Long-term reduction in rainfall due to natural rainfall cycle.
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Other cards in this set
Card 2
Front
What is a desert fringe?
Back
- The 'buffer' between desert and 'normal' land. - Supports greater biodiversity and larger plants, than in the middle of the desert.
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