hot deserts

• hot deserts are generally found around the tropics, and are characterised by high temperatures and low rainfall.
• causes of deserts: at the equator, warm air is forced to rise (making low pressure). It then cools, condenses and forms clouds, resulting in rain. At 30 degrees north and south of the equator, the air sinks forming high pressure which brings dry weather.
• factors that affect biodiversity: little and infrequent precipitation, cold night time temperatures, soil lacking organic content, moving sand and high temperatures.
• camel adaptions:

  • can drink lots of water
  • long eyelashes and thick eyebrows to protect from sand
  • thick fur to keep them warm
  • wide padded feet to walk easily on the sand
  • a hump which stores fat and provides energy
• biodiversity: the variety of life in a particular habitat
• kangaroo rat adaptions:

  • they are nocturnal so they only come out when it is cooler
  • expandable cheek pouches to carry food
  • large back legs to support the body
  • a long tail to scare predators
• saguaro cactus adaptions:

  • long root system to maximise water intake
  • can store up to 5 tonnes of water
  • pleats on the trunk allow it to expand rapidly.
• other plant adaptions: small leaves and a waxy cuticle.
• the Thar desert is found in Asia in the state of Rajistan. It is known as the great Indian desert and covers an area of 200000 km^2.
• Thar desert:

  development opportunities:

  • the desert region has lots of valuable minerals which can be exported. For example, gypsum which is used in construction to help make cement.
  • there are lots of tourist attractions like safaris and the annual desert festival. These events provide jobs and money for locals.
  • there is also lots of commercial farming opportunities, meaning crops can be exported.
  • the Indira Gandhi canal is a source of fresh water for locals and has helped to revolutionise farming.
• Thar desert:

  challenges:

  • extreme temperatures can lead to droughts and water shortages.
  • there are often water shortages which can lead to dehydration and affect crop growth.
  • there is also a very limited road network making it difficult for products to get in and out of the area.
• Thar desert environment: the landscape is made up of sandy hills with few trees and shrubs. The rainfall is low (100-240 mm annually) and the temperatures are high (up to 53 degrees Celsius).
• desertification: the process by which land becomes drier and degraded - more desert like.
• desertification:

  natural/physical causes:

  • climate change - it can cause higher temps and drier conditions.
  • soil erosion - when vegetation has been destroyed, it leaves the soil exposed and vulnerable to erosion.
• desertification:

  human causes:

  • population pressure - more people means more food is needed which results in less vegetation being available.
  • overcultivation - this can lead to soil becoming exhausted and infertile.
  • poor land management - this can cause plants and growing crops to die.
  • politics - following the 1991 Gulf war, large herds of sheep moved which lead to overgrazing and desertification.
• managing desertification:

  • Badia, Jordan - people are building low stone walls that stops water rom running down. This water can then be used for watering plants.
  • ponding banks - areas of land enclosed by low walls to store water and stop it washing soil away.
  • contour traps - embankments built along the contours of slopes to prevent soil being washed away.
  • creating national parks
  • tree planting - reduces soil erosion, provides shade and grazing for animals.
• salinisation: excess salt minerals
• overcultivation: exhausting the soil by overcropping the land.