hot deserts

• deserts

  • an area that receives less then 250 mm of rain per year
  • formed when rain clouds run into wind or mountains and drop rain in 1 area (leaving the land further away dry)
  • location: 30 ° north and south of the equator (near the tropics)
  • continent and countries: africa, algeria (sahara desert)
  • climate: dry air, no condensation or rain, clouds rarely form (area of high pressure), hot during the day and cold during the night and has dry monsoon seasons (with regular dust storms)
• deserts

  • environment: low and sparse vegetation (due to the lack of water), biodiverse, little organic matter
  • soils: sandy, stony and infertile
  • can soak up water rapidly after rainfall and are able to conserve moisture
  • problems facing plants and animals: lack of water and extreme temperatures
• human causes of desertification

  • climate change and drought - more droughts than normal has damaged animals habitats and soil, can be solved by dams (store water to use on fields and can be used as a well to collect water)
  • deforestation - left soil unprotected and infertile (wind and rain washes the nutrients away), can be solved by afforestation (helps the soil to be restored and protected from soil erosion)
  • population growth/overgrazing - the need for more food and homes puts pressure on land, but can be solved by using drought resistant crops that can produce more food from less land
• human causes of deforestation (2)

  • over farming and poor farming methods - the over use of land without allowing the nutrients to return to the ground leaves infertile soil, can be solved by educating farmers on their farming methods (so they use the land in a productive way)
  • over use of fertilisers - a breakdown of the soil quality leaves salty soil and crops that are unable to be planted, can be solved by using natural fertilisers
• physical causes of desertification

  • lack of water - causes crops to die and poor farming methods to be used, can be solved by building terraces on the land to help reduce the amount of runoff
  • climate change and drought - more droughts than normal has damaged animals habitats and soil, can be solved by dams (store water to use on fields and can be used as a well to collect water)
• plant adaptations

  • cactus - long horizontal taproots can reach underground water and small and waxy leaves helps to reduce water loss
  • ephemerals - lie dormant until it rains, grow quickly before rainwater gets evaporated
  • xerophytes - green to increase rate of photosynthesis and have a small surface area to reduce transpiration
• animal adaptations

  • camels - large feet spread out weight on sand and fat stored in humps stores energy without insulating the whole body
  • fennec fox - thick fur helps to insulate from cold nights and reflects heat and burrowing and nocturnal lifestyle restricts water loss
  • jerboa - short forearms and powerful hind legs helps with digging and folds of skin close off their nostrils to sand
  • rodents - sheltering during the day helps prevent dehydration and only venture out during the cooler nights
• methods of managing desertification

  • afforestation - important way of reducing erosion (tree roots bind the soil together and the branches provide shade for grazing animals) example: prosopis cineraria
  • technology - using practical methods that are appropriate to each level of development (they might not have access to expensive machinery)
• too much irrigation can cause problems leading to a salinisation which reduces soil fertility and kills plants (because of the high rate of evaporation in hot deserts leads to a build up of salts on the surface)
• desertification and the indira canal


  • constructed in 1958, is 650 km long and revolutionised farming and crops by being the main source of irrigation, fresh water and enhanced commercial farming (wheat and cotton)
  • desertification: when land is gradually turned into desert
  • areas at risk from desertification are on the borders of existing deserts (are ecologically fragile, so slight changes in temperatures and rainfall that are associated with climate change can have serious impacts)
  • linked to soil erosion
• desertification in jordan (badia)

  • 80% of jordan is badia
  • lack of water is a major problem for people living there
  • much of the land was been traditionally grazed by the nomadic bedouin
  • following the gulf war, jordanian land was overgrazed and therefore desertified
  • desertification made the land unproductive, people moved away and without vegetation, soil erosion became a major problem too
• • barren: little vegetation growing on land
  • nomadic: not settled
  • sustainable: a method of using a resource that is not permanently damaged
  • nocturnal animals: sleep during the day
  • badia: dry and rocky desert (located in eastern jordan)
  • overgrazing: when there are too many animals to be supported by the limited vegetation (caused by population pressure)
  • soil erosion: when vegetation has been destroyed the soil is exposed to the wind and the rain, making it vulnerable to erosion