hot deserts

What is the climate in a hot desert like?

• Temperatures are extreme (can range from 45°C during the day, to 0°C at night) → lack of cloud clover due to high pressure belt at 30°N and S

• Low precipitation → less than 250mm a year

What is the soil in a hot desert like?

• Infertile → a lack of vegetation means a lack of leaf fall, therefore little biomass is decomposed to form nutrients

• Dry → lack of rainfall

• Shallow and gravelly in texture

What are plants in a hot desert like?

• Plant growth is sparse and minimal → lack of rainfall

• Those that do grow require little water, e.g. cacti

• Plants are generally short

• Many plants have short life cycles, quickly growing after rain

What are animals in a hot desert like?

• Mammals tend to be small and nocturnal to save energy

• Most birds leave the desert during the harshest conditions

How are hot deserts interdependent ecosystems?

All the biotic and abiotic components in hot deserts depend on each other.

EX: Cattle overgraze land → fewer plants stabilising soil → soil erosion → dust clouds → reduction in rainfall → desert become drier → plants/animals/people may die

How are plants adapted to the physical conditions in hot deserts?

• Plant roots are:

  • extremely long to reach deep water supplies or,

  • spread out wide near the surface to absorb as much water possible when it rains

• Some plants have small leaves/spines to lower the surface area and reduce the loss of water via transpiration

• Some plants only germinate after it rains, growing quickly to take advantage of the wet conditions

• Many plants are succulents (e.g. cacti) → they store water in their roots/stems/leaves

How are animals adapted to the physical conditions in hot deserts?

• Many animals are nocturnal → they sleep when temperatures are hottest, helping them stay cool

• A lot of desert animals have long limbs/ears to increase their surface area so that they lose more heat, faster

• Bigger animals, such as camels, store fat that they break down into water when needed

• Most desert animals sweat and urinate as little as possible to reduce water loss (e.g. kangaroo rats don’t sweat)

What are some threats to biodiversity in hot deserts?

• Climate change

• Desertification

What is an example of a hot desert?

The Thar desert located in north-west India and south-eastern Pakistan.

What are some development opportunities in the Thar desert?

• Mineral extraction

• Energy

• Farming

• Tourism