Deserts Flashcards
Definition of a desert
An area receiving less that 250mm of rainfall resulting in extreme aridity
Physical characteristics of a desert
Dry
Arid
Barren
Lack of biodiversity
Lack of cloud cover
High insolation
Rocky/sandy
Where are deserts found
Between the topics - 15 to 30 degrees north and south of the equator
Why are deserts located there?
Air is sinking near the tropics
Leading to areas of high pressure
This results in few clouds
Temperatures are therefore hot in the day and cold at night
Describe desert soil
Fewer minerals and nutrients
Lack of vegetation stabilising the soil
What do plants do to help soil (interdependence)
Provide shade to stop the soil losing water
Provide nutrients as dead matter is broken down
What does the soil do for the plants (interdependence)
Provides the structure for the roots to take and grow
How to humans positively impact interdependence
Plantation
Afforestation
Ecotourism - educational
Sustainable land practices
How do humans negatively impact interdependence
Footpath erosion
Farming ruins land
Urbanisation disrupts vegetation
Untrainable use of limited water
Name of plants that survive very dry conditions
Xerophytes
How do xerophytes adapt
Thick waxy cuticles and shed leaves to reduce transportation to minimise water loss
Fennec fox adaptations
Large ears - dissipate excess body heat
Thick fur - insulation for cold nights
Sandy fur - camouflage
Thick fur on soles of feet - protect from hot sand
Camel adaptations
Can go a week without water
Store fat in hump - metabolised for energy
Feet are wide - walk on sand easier without sinking into it
Challenges of developing desert areas - climate change
Temperatures forecasted to rise
Threatens water security - reduced rainfall - droughts
Challenges of developing desert areas - climate
Plants and animals have to adapt
Extreme temperatures hard for farmers
how are plants adapted to help water conservation
waxy cuticles - minimise water loss via transpiration
challenges of developing desert areas - transport and accessibility
Low population - lack of surfaced roads - access is limited
challenges of developing desert areas - water supply
as demand increases will become a bigger issue, water security is also threatened by climate change
Has an impact on tourism and farming
Could cause conflict of use
opportunities of developing desert areas
People enjoy the peaceful landscapes (e.g. Las Vegas has 37 million tourists per year)
High temps and sunlight = favourable conditions for agriculture
Strong insolation - good for solar energy schemes
Western desert water crisis
Water level dropped in the Colorado River - now only 38% full
Goes through 7 states - the river gives opportunities (helps farming) - jobs, health, recreation
Conflict could be created with a lower supply than demand
Desertification definition
The process by which land becomes drier and degraded as a result of both human activities and natural processes
Where are areas at risk of desertification found usually
Near the equator
Causes of desertification (5) with reasons
Climate change - Significant reductions in annual rainfall - more droughts and soil becomes drier
Population growth - Higher demand for food - land is put under pressure for agriculture to grow more crops - leads to vegetation destruction, soil erosion and desertification
Removal of fuelwood - Land stripped of its trees - vulnerable to erosion by wind and rain - degraded
Overgrazing and overcultivation - exhausts the soil of its nutrients
Soil erosion - rainfall/wind - washes away soil leaving behind very infertile sub-soil
Why is vegetation important for the protection of soil in dry areas
Trees provide shade to ensure the soil does not dry out from the heat
It provides root systems to avoid the soil eroding away
They intercept rainfall to ensure soil is not washed away
Roots also give nutrients back to the soil to keep it rich and healthy
