Hot Deserts

• what are the physical characteristics of a hot desert?

  an area with less than 250 mm of rainfall a year. it is dry and arid.
• the interdependence of climate, water, soils, plants, animals and people

  people depend on animals for food and milk. plants rely upon soil for their nutrients through dead vegetation. plants retain more water and provide shade so the soil is not cracked and the rain can gently hit the surface. Plants tie soil together and prevent soil erosion and excessive leaching. In Oasis, water can be found close to the surface to make agricultural possible. Food webs also exist.
• what is the climate of deserts?

  lack of clouds and rain and high temperatures. but during nightime they can go to below freezing.
• what is the soil like in deserts?

  sandy and stony with lack of vegetation. dry but can soak up water rapidly after rainfall. they are not very fertile.
• how have plants adapted to deserts?

  1) plants have horizontal root systems, just below the surface.

  
  

  2) seeds can stay dormant for rain and germinate quickly when it rains.

  
  

  3) some plants store water in their roots.

  
  

  4) small leaves with spines and waxy leaves helps reduce water loss and discourage animals from eating it.

  
  

  5) some plants have long taproots to reach groundwater.
• how have animals adapted to deserts?

  CAMELS:

  
  

  1) store energy/food in their hump.

  
  

  2) thick fur protects it's skin from heat.

  
  

  3) large, flat feet for weight distribution

  
  

  4) thin fur at the stomach to let heat out.

  
  

  5) can go a long time without water as they don't lose a lot through urination/sweating.

  
  

  6) long eyelashes and thin nostrils helps keep sand out.
• where are hot deserts found?

  found in all continents between the Arctic and Antarctic circle, 30 degrees, North and South of the equator. larger deserts are found in Northern Africa and Central Europe.
• where is the thar desert?

  north west India, into Pakistan. the most densely populated desert in the world. Above the tropic of Cancer. West of New Dehli. South East of the River Sutlej.
• what is the thar desert?


  soils are sandy with a mixture of small shrubs and small trees. low rainfall with summer temperatures of 53 degrees.
• what development opportunities are there for deserts?

  mineral extraction, energy, farming and tourism.
• How can land be used for Tourism?

  popular tourist destinations for desert safaris at Jaisalmer. Annual desert festivals and local people provide accommodation, food and water as well as looking after camels. This helps create job opportunities.
• how can land be used for Farming?

  Irrigation helps more crops grow and makes commercial farming more popular. Subsistence farming is mainly used. water is brought from the river sutlej.
• how can land be used for energy production?

  Solar panels are useful as there are cloudless skies.

  
  

  Wind is used as there are 75 wind turbines. The Jaisalmer Wind Park was created.

  
  

  An oilfield has been discovered

  
  

  There are coal deposits and thermal energy plants have been constructed.
• how can land be used for mineral extraction?

  gypsum can be used for making plaster and cement. ceramics, marble and limestone is found. Minerals for fertilisers are used. As well as valuable reserves of stone for the construction industry.
• what are the challenges of development?

  extreme temperatures, water supply and lack of accessibility.
• what are the challenges of extreme temperatures?

  exceeding 50 degrees means working outside can be very hard. high rates of evaporation lead to water shortages. Plants/Animals have to adapt or need to be cared for, some are nocturnal and some need shade.
• what are the challenges of water supply?

  Demand of water increases due to increasing population. there is high evaporation and low rates of rainfall. Traditionally, water is stored in ponds. Settlements are close to rivers (but there are very few of them). Aquifers can obtain underground water but it is salty and poor quality.
• what are the challenges of lack of accesibility?

  limited road networks, tarmac can melt and strong winds can blow sand/dust onto the road. Public transport is buses but traditional transport is camels.
• areas on the fringe of hot deserts are at risk of ....

  desertification
• what is desertification


  The process by which land becomes drier and degraded as a result of human activities, climate change or both. (it is not natural).
• how does desertification work?

  deserts grow in size, when soil is damaged and poor land management the grass can get covered with sand.
• where is desertification a problem?

  at borders of existing deserts such as the Sahara. eg. Australia, Spain and parts of the USA.
• what are the causes of desertification?

  climate change, population growth, removal of fuel wood, overgrazing, over-cultivation and soil erosion
• strategies used to reduce the risk of desertification?

  water and soil management, tree planning and use of appropriate technology.
• how does climate change cause desertification?

  drier conditions with unreliable rainfall.
• how does population growth cause desertification?

  demand for more fuelwood which causes trees to dry. too many animals but limited vegetation leading to overgrazing.
• how does soil erosion cause desertification?

  if vegetation is destroyed the soil is more exposed to winds and rain.
• how does overgrazing and overcultivation lead to desertification?


  the need to produce more food can exhaust the soil making it infertile.
• how does water/soil management reduce the risk of desertification?

  commercial farming can lead to overirrigation can lead to salinisation, increasing evaporation and reducing soil fertility. Ponding banks can store water and Contour traps are embankments that prevent soil from being washed down.
• how does tree planting reduce the risk of desertification?

  roots bind the soil and leaves provide shade and fuelwood.
• how does the use of appropriate technology reduce the risk of desertification?

  sustainable approaches are used as access to expensive machinery may be limited.
• what is salinisation of soil?

  in a hot dry climate where evaporation rates are high, the salts in water stay on the surface while the water is evaporated. this can build up in the soil and kill plants.
• what are magic stones?

  a line of stones to reduce erosion, basic tools and tracks transport the rocks while local people set it up. When it rains, the water is traped so can't erode soil. This increased crop yield by 50%.
• What does planting acacia trees do?

  planting thesetrees provides nutrients, produce food and gum and also retains water.