Case Study - Thar Desert / Sahel Flashcards
Background (Thar Desert)
Border between India and Pakistan in S. Asia
More people planning to live in desert due to increasing population
Distribution of world’s hot deserts
Subtropics; between 20-30 degrees N/S of the Equator
Tropics of Cancer and Capricorn run through most of the world’s hot deserts
Major characteristics of hot deserts
- aridity (annual rainfall < 250mm)
- heat (>40 C)
- landscapes - mostly rocky with thorny bushes, though some have dunes
Hot deserts inhabitants
- people live in large open tents to keep cool
- food cooked slowly in warm sandy soil
- head scarves provide protection from the sun
Climate
- less than 250mm rainfall per year
- may rain once every 2-3 years
- 50C in the day, 5C in the night (averages)
- occasional frost and snow in winter
Annual rainfall
~250mm
Average temperatures (day and night)
50C in the day
About 5C in the night
Cactus - adaptations
- widespread roots absorb water soon after rainfall (e.g., saguaro cactus roots spread 15m in each direction, but only 15cm deep)
- needles instead of leaves reduce surface area, and therefore, transpiration
Camels - adaptations
- humps help to store fat
- wide feet for walking on sand
- long eyelashes to protect from sand
Desert interdependence
Different parts of the ecosystem are closely linked together and depend on each other, especially in such a harsh environment
Opportunities for development
- valuable minerals for industry and construction
- energy resources e.g. coal, oil
- renewable energy, such as solar power at Bhaleri
- tourists attracted, especially during festivals
Challenges for development
- extreme heat makes it difficult to work outside for long periods of time
- evaporation rates from irrigation canals and farmland
- limited water supplies struggle to sustain increasing population
- roads are difficult to build and maintain
Causes for desertification (Sahel)
- fuel wood
- over-cultivation
- climate change
- overgrazing
- population growth
Desertification - fuel wood (Sahel)
The removal of trees by people needing fuel causes the soil to be exposed
Desertification - over-cultivation (Sahel)
If crops are grown in the same area too often, nutrients all get used up causing soil erosion
Desertification- climate change (Sahel)
Less water is available for plants, due to reduced rainfall and rising temperatures
Desertification - overgrazing (Sahel)
Too many plants are eaten faster than they can grow back, due to the high number of animals
Desertification - overpopulation (Sahel)
More pressure is put on the land by people needing resources, causing deforestation, over-grazing and over-cultivation
Strategies to reduce desertification (Sahel)
- water management
- tree planting
- technology
- soil management
Reducing desertification - water management (Sahel)
Growing crops that don’t need much water
Reducing desertification - tree planting (Sahel)
Trees can act as windbreakers to protect the soil from wind and soil erosion
Reducing desertification - soil management (Sahel)
Leaving areas of land to rest and recover lost nutrients
Reducing desertification - technology (Sahel)
Using less expensive, sustainable materials for people to maintain e.g., magic stones
