GCSE 1.B - Living World ( Hot deserts ) Flashcards
What is the definition of a desert?
A biome that has less than 25cm of rain a year
What are the characteristics of a desertt?
few trees and plants from lack of water
Few animals from not enough t eat and strong winds can whip sand up into dust and feirce storms
Huge temperature range
What are some examples of deserts?
Sahara
Australian
Araibian
Where are hot deserts found?Why?
Along the tropics of cancer and capricorn, this is where the air in a hadley cell sinks back to earth which creates high pressure and dry conditions
why is there a big temperature range in the deserts?
The lack of clouds allows the land to warm up quickly during the day and loose heat quickly at night
WHat are some animal examples of adaptaions in hot deserts?
a rattlesnake - has waterproof skin so it cannot loose moisture as easily
Kangaroo Rat- all the water it needs is from its food
camels- food istored in their humps so they can go days without it
what are some plant adaptations in hot deserts?
euphrates popular tree
sand verbena
saguero cactus
Euphrates popular tree
long tap roots to reach water deep down
shared root systems for mutual benefit
sand verbena
complete full life cycle in a few weeks
saguaro cactus
can store up to 5000l wate4
spines insteas of leaves to prevent transpiration
INTERDEPENDANCE
pack rat and Cholla (teddybrear cactsu)
the pack rat takes bits of the cactus that have fallen off the protect its burrow. this meas the cactus with take rot far from the parent plant to reduce competition
INTERDEPENDANCE
Mesquite and sagura cactus
Mesquite tree protects cacti form extreme wearther and draws up water for it to use
Desertification
the process of land turning into desert. this usually occurs on the edges of existing desert
what is desertification caused by?
overgrasing
overcultivation
population growth
OverGrasing
areas are stripped of vegetation by grasing animals and it exposes the soil. this then gets eroded by wind or water
How can Overcultivation destroy a desert or cause one?
the sol can become exhausted (stripped oof nutrients). it will turn to dust and become infertile
Population growth
lead to increasing demand for fuel wood, the trees are stirpped of their branches and eventually die(with the trees goes the moisture)
what are the consequences of desertification?
Famine
Loss of biodiversity and livestock
food insecurity
what is a solution to desertification
stone lines/magic stones
great Green wall
stops climate change - stores co2
acts as a wind break
provides jobs
trees store moisture
What opportunities are there in the thar desert?
Tourism - from pakistan, camel rides, winterfestival
Mineral extraction - gypsum, fieldspar,phosphorite
Energy - coal, oil, wind, soil
Farming - Subsistance, Commercial (irrigated)
What are the challenges of the thar desert?
rainfall is low- no water
veyr sandy- hard to build
infertile soil - no plants
ectreme temps
inaccesability - extreme weather
What are desert soild like?
Infertile, sandy or stony
THAR DESERT
Tourism
tens of thousand visit the desert each year
Deset safaris on camels based at Jaisalmer, Annual desert festival held in winter. local people benefit by providing food and accomodation and by acting as guides or rearing and looking after camels
THAR DESeRT
Mineral extraction
The desert reigion has valuable reserves of mineral which are used all over India and exported all across the world
Feldspar (used to make ceramics) - 66% of Indias production comes from Rajasthan
kaolin ( used as whitener in paper) - Producing 16% of the nation’s output
also valuble reserves of stones such as limetone in the region
THAR DESERT
Energy
The Thar desert is a rich energy sourcee
Oil - a large oilfield in the barmer district makes a large contribution teh states revenues (US$5.3Billion in 2009-2018)
Solar - Hot desert is the perfect climate and conditions for solar power constructions. A huge solar park is being constructed at Bhadla. Spreas across 40km , it will generate enough electricity to meet Rajasthan’s needs
THAR DESERT
What Farming types are in the Thar desert?
Most people living in the desert are involved in subsistence farming. They survive in the hot and dry conditions by grasing animals on the grassy areas and cultivating vegatbles and fruit trees
commercial farming, Has been possible by irrigation. The construction of the Indira Ghandi Canal in 1958 has revolutionised farming, crops such as wheat and cotton now thrive in an area that used to be scrubby desert.
THAR DESERT
How does Extreme temps limit the development of the Thar desert?
In 2016 a record temp for india was 51C was recorded at Phalodi in Rajasthan
The Extreme heat presents health challlenges for people working outside e.g. tour guides, farmers
Tourism Is seasonal because it is limited to the cooler months
Extreme heat can lead to dehydration of animals and plats, affecting biodiversity and farming
THAR DESERT
Water supply - who supplies? Problem?
High demand for water
The Indira Ghandhi Canal
The main source of irrigation in the Thar Desert, and a major source for the economy, supporting farming, mining, and tourism
THAR DESERT
How does Inaccesability limit development?
Due to very extreme weather and vast barren areas there is a very limited road network across the Thar Desert. High temps can cause tarmac to melt and the strong winds often blow sand over the roads.
Many places are only accesible by camel, Public transport often involves seriously overladen buses
What are the threats to biodiversity in hot deserts?
Climate change - Changing patterns of rainfall and increased frequency and intensity of droughts threaten the delicate ecological balance, as water holes and rivers may flood or dry up
Wildfires - May become more common, replacing slow-growing shrubs and trees with faster-growing grasses, altering the ecosystem
Overgrasing - Over cultivation and exessive gathering of firewood in desert margins can destroy vegetation, exposing the soil to erosion by wind and rain -> desertification
Desert tourism - Off-road vehicles can damage desert vegetation and disturb wildlife
How does salinisation happen in hot deserts?
When commercial farming involves irrigation. Water from underground sources or from rivers and canals can be sprayed onto crops or used to flood fields. Too much irrigation can cause problems leading to salinisation - a build up of salt on the surface of the land - soil fertility is reduced and plants can die
What are local farmers in Australia encouraged to use to prevent soil erosion?
Ponding banks - areas of land enclosed by low walls to store water
Contour traps - embankments built along the contours of slopes to prevent soil from being washed down during heavy rainfall
National parks - prevent desertification
In some parts of the world, hot desert areas at risk of desertification have been protected by making them into national parks
- The Desert National Park in the Thar Desert, India, was created in 1992 to protect some 3000 Km of desert and reduce the risk of desertification
Trees planting - Prevent desertification
Tree planting is an important way of reducing soil erosion and desertification. Tree roots bind the soil together, and the leaves and branches act like an umbrellla, protecting the soil from rain
- In the Thar desert, a community-led project has planted one million trees to from a “green wall” at Bikaner in Western Rajasthan with the aim of reducing soil erosion by wind and reducing desertification
Preventing soil erosion/ reducing risk of desertification - Appropriate technology
Involves using cheapm sustainable and avaliable materials appropraite to local communities often experiencing low levels of economic development.
Stone bunda in Burkina Faso, West Africa
- Using basic tools and trucks to transport the stones, local people have built low stone walls between 0.5m and 1.5m high along the contours of the slopes. When rain washes down the hillside, the wallls trap water and soil. This has helped to increase crops by up to 50% and reduce desertification
What are the threats to the Sahara’s biodiversity?
Climate change - Changing rianfall patterns and increased frequency of droughts
Wildfires - Replaces slow growing shrubs and trees with faster-growing grasses, altering the ecosystme
Over-grasing/over-cultivation and exessive gathering of firewood in desert margins can destroy vegetation
Desert tourism - Off-road vehicles can damage desert vegetation and disturb wildlife
Stats - Mineral extraction in Thar
Feldspar - used for ceramics - 66% of India’s production comes from Rajasthan
Phosphorite - Used for making fertilisers - 95% of Indias production comes from Rajastahan
Examples - Solar Energy in Thar
Solar park is being constructed in Bhadla. Spread across 40km, it will generate enough electricity to meet Rajasthan’s needs
Ex - Thar commercial farming
Indira Gandhi Canal (Main source of irrigation in Thar) in 1958 allows the gowth of vital crops such as wheat and cotton
Also provides drinking water and mitigates desertification + tree plants
