AQA GCSE Geography: Living World- Hot Deserts
Terms in this set (16)
HOT DESERTS: Characteristics of a Desert
extreme temperatures- During day temperature may reach 50°C. Night may fall to below 0°C. Rain unreliable- less than 250 mm of rainfall per year. Most deserts found between 20° and 35° north and south of equator.
HOT DESERTS: What 3 factors form desert areas?
1. presence of high pressure- creating cloud-free conditions
2. cold ocean currents
3. mountain ranges to create rain shadows
HOT DESERTS: Plant adaptations in desert
-Plant roots either extremely long (reach deep water), or spread out wide near surface (catch as much water as possible when it rains)
-CACTI swollen stems to store water+thick waxy skin reduce water loss.
-Cacti+other small bushes small, spiky leaves to reduce water loss.
-Seeds some plants only germinate when rain- only grow when enough water to survive.
HOT DESERTS: Transpiration
Water loss from plants
HOT DESERTS: LEDC Case Study
Thar desert, Pakistan
HOT DESERTS: THAR desert human uses
HOT DESERTS: THAR Hunting+ gathering
Tribes (BALUCHIS) are NORMADIC PASTORALISTS (keep moving- fresh grazing for mixed livestock) All animals (sheep, goats, camels) highly adaptable- can survive on little water and dry vegetation. Animals supply most needs of tribe; milk, meat, wool and skins for leather goods.
HOT DESERTS: THAR farming
Most inhabitants SUBSISTENCE FARMERS (basic need of farmer). Population densities low - under 10 people pkm2. BUT in EAST densities higher- sometimes over 50 people pkm2. STRAIN ON NATURAL RESOURCES.
HOT DESERTS: THAR Irrigation
LEDC so lack of resources+money means harder find sources of water or extract it. Sometimes water can be obtained through traditional methods used for centuries- PERSIAN WHEEL. Means people can grow staple food crops.
HOT DESERTS: THAR Challenges of living there
Increase in sheep+goats has serious knock-on effect- leading severe problems overgrazing, SOIL EROSION. Made worse by clearances vegetation for firewood. In crop-growing areas, fallow periods to allow ground recover being reduced.
HOT DESERTS: THAR Management
Tribes too poor to undertake initiatives to increase sustainability (reducing herd numbers+increasing animal quality, building small dams and planting fast-growing trees- stabilise dunes). Few areas aid agencies active- small communities introduced to water saving+more sustainable techniques (building small earth dams).
HOT DESERTS: MEDC Case study
Mojave Desert, USA (California, Nevada, Utah, Arizona)
HOT DESERTS: Uses of Mojave
-Commercial farming- cattle ranches in region over 100 years- main type farming. Fruit+V cultivations on irrigated valley floors.
-Retiring- Good weather. 80% people Sun City Arizona over 65. Desert overall sparsely populated but certain areas concentrated densities. Las Vegas USA's fastest growing city.
-Irrigation- Used to allow for newactivities. Water comes from groundwater (aquifers), Mojave river and Colorado river. Most diverted to S California supply fruit+cotton farms and cities.
HOT DESERTS: Other uses of Mojave
-Tourism- Tourist destinations inc Las Vegas, Death Valley and Grand Canyon. Death valley national park 1 mil tourists per year. Tourists attracted by wildlife, weather, geology+activities (camping)
-Mining- In past, Gold, silver, copper, lead, salts mined though most mines closed. Still some borax mines
HOT DESERTS: Negative impacts of Mojave uses
-Rapid population growth depleted water resources- Colorado R no longer meet demands- reaches sea in Mexico as trickle, annoys Mexicans+costs them. Las Vegas using aquifer too quickly than being naturally replenished.
-Farming uses lots water, also causes soil erosion
-Tourists deplete water resources, drop litter, damage plants+cause soil erosion.
HOT DESERTS: Management strategies in Mojave
-Water conservation schemes- MOJAVE WATER AGENCY vouchers buy water efficient toilets+washing machines. Pay people remove grass lawns, replace with plants needing less water.
-4 national park- native species protected+strict rules land use. Conserves area.
-Designated roads off-road vechiles- conserve plant life.
-Some hotels try conserve water (MGM Mirage hotels use drip-irrigation to water lawns).