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Geography - Hot deserts - Coggle Diagram
Geography - Hot deserts
Characteristics of Hot Deserts
Location
Found between 15° and 30° north and south of the Equator
Around the Tropics of Cancer and Capricorn
Examples: Sahara, Arabian Desert, Australian deserts
Climate
Less than 250 mm rainfall per year
Rainfall is infrequent and unpredictable
Day temperatures can exceed 45°C
Night temperatures can fall below 0°C
Very low humidity
Soil
Thin and shallow
Dry due to little rainfall
Sandy and gravelly texture
Low fertility
Low organic matter
Plants
Sparse vegetation
Cacti
Thorn bushes
Short life cycles after rainfall
Animals
Specially adapted to harsh conditions
Small and nocturnal
Kangaroo rats
Roadrunners
People
Live near water sources
Oasis settlements
Many indigenous groups are nomadic
Biodiversity and Interdependence
Biotic Factors
Plants
Animals
People
Abiotic Factors
Climate
Water
Soil
Relief
Interdependence
Plants absorb nutrients and water
Animals eat plants
Animals disperse seeds
Everything is connected
Fragile Ecosystem
Sparse vegetation means food is limited
Low-density populations of animals and people
Small changes can affect the whole ecosystem
Threats to Biodiversity
Habitat destruction
Road building
Water extraction
Pollution
Global warming
Increased human activity
Adaptations of Plants
Roots
Very long roots reach deep groundwater
Wide shallow roots quickly absorb rainwater
Water Storage
Succulents store water
Thick fleshy stems
Reducing Water Loss
Small leaves
Spines instead of leaves
Thick waxy cuticle
Reduced transpiration
Reproduction
Seeds remain dormant
Germinate rapidly after rain
Adaptations of Animals
Avoiding Heat
Nocturnal behaviour
Rest during the day
Shelter in burrows
Staying Cool
Large ears increase heat loss
Small body size
Conserving Water
Little sweating
Concentrated urine
Obtain water from food
Desert Survival
Camels store fat in humps
Can go long periods without water
Long eyelashes
Triple eyelids
Closable nostrils
Wide feet prevent sinking in sand
Desertification
Definition
Land becomes increasingly desert-like
Causes
Physical Causes
Reduced rainfall
Drought
Higher temperatures
Increased evaporation
Human Causes
Deforestation
Overgrazing
Over-cultivation
Population growth
Removal of fuelwood
Impacts
Soil erosion
Nutrient loss
Vegetation loss
Reduced crop yields
Expansion of desert conditions
Reducing Desertification
Water Management
Drip irrigation
Drought-resistant crops
Efficient water use
Tree Planting
Windbreaks
Reduce erosion
Provide shade
Stabilise soil
Soil Management
Leave fields fallow
Crop rotation
Add compost
Restore nutrients
Appropriate Technology
Sand fences
Small-scale irrigation systems
Solar cookers
Techniques affordable for local people