Processes and Consequences of Desertification

Question 1

What are the usual causes of desertification?

Answer 1

Precipitation becoming less reliable, seasonally and annually.
Vegetation gets water-stressed and dies off, exposing bare soil.
Bare soil is vulnerable to erosion by wind and water.
Short, intense precip results in rapid runoff, reducing soil moisture store.

Question 2

What human factors can reinforce the physical causes?

Answer 2

Over-cultivation and an increase in large-scale, mechanised agriculture
Overgrazing by goats, sheep and cattle.
Deforestation and the use of trees for fuel and construction.
Population growth and pressure.
Change from nomadic to sedentary agriculture.
Civil wars.

Question 3

What is the impact of desertification on ecosystems?

Answer 3

Habitat ranges are changed.
Tipping points reached more quickly.
Extinction risks.
Animal and plant life cycles changed.
Food webs widely affected.
Changing distribution of disease.

Question 4

What is the impact of desertification on populations?

Answer 4

Reduced soil fertility
Soil erosion
Dust storms
Breakdown of society
Drought and famine
Forced migration
Loss of Land
Loss of Culture

Question 5

What is the impact of desertification on landscapes?

Answer 5

Soil erosion
Increased amount of sand.
Increased treeless areas.
Increased sedimentation
Increasing salinity.
Increased sandstorms
Vegetation damage from sand-blasting.