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Fragile environments under threat
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A fragile environment is easily damaged and slow to recover. Desertification and deforestation are two of the biggest threats.
Fragile environments
Examples: hot deserts and their semi-arid edges (such as the Sahel), tropical rainforests, tundra and polar regions, mountains and coral reefs.
Causes of desertification
Climate: falling or less reliable rainfall and droughts.
Human: overgrazing by too many animals, overcultivation that exhausts the soil, cutting trees for fuelwood, and poor irrigation that leaves salt in the soil (salinisation).
Population growth increases all of these pressures.
The Sahel, south of the Sahara, is a well-known example.
Causes of deforestation
Logging for timber.
Mining, roads, dams and settlements.
Population growth and poverty push people to clear land.
Explain how overgrazing can lead to desertification.
- Too many animals eat the vegetation faster than it can grow back.
- Bare soil is exposed to wind and occasional heavy rain.
- The topsoil is eroded, so the land can no longer support plants.
Answer: Vegetation loss exposes soil to erosion until the land is degraded.
Fragile environments (deserts and their edges, rainforests, tundra, mountains, coral reefs) are easily damaged and slow to recover. Desertification is caused by drought and by overgrazing, overcultivation, fuelwood collection and poor irrigation, worsened by population growth. Deforestation is driven by farming, logging, mining, roads, dams and settlement.
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