✅desert Flashcards
biodiversity
variety of plants and animals in a particular ecosystem
what is a hot desert
an area of dry land —> less than 250mm of rainfall per year
temps up to 50 degrees
where are hot deserts found
30 degrees north and 30 degrees south of the equator
what is climate like (temp and precipitation)
temperature
up to 50 degrees during the day and below 0 degrees at night
precipitation
less than 250mm of rainfall per year
why is it hot and dry in deserts
hot —> close to the equator where sun rays are more concentrated
dry —> in areas of high pressure where air is sinking
what is the soil like in a hot desert
dry
coarse texture
infertile
what plants and animals would you find in a hot desert
animals that are well adapted to the hot, dry climate and limited vegetation
animals are generally very small in size and tend to sleep through the day time when temperatures are high
limited plants —> those that do grow are short and don’t live a long time
how have animals adapted to hot deserts (camels)
bushy eyebrows and 2 layers of eyelashes to protect eyes from sand
flat wide feet so they don’t sink into the sand
long legs to keep their body away from the hot sand
how have animals adapted to the desert (emu)
unique double quilled feather that protect them from heat
how have plants adapted to hot deserts (cacti)
spines to deter predators
thick, waxy skin to reduce water loss
stems that store water
what is biodiversity like of hot deserts
limited due to extreme weather
this means any changes can have drastic consequences
global warming is the biggest threat to hot dexter’s biodiversity
why are hot deserts an interdependent ecosystem
plants gain nutrients from the soil and animals get energy/nutrients from plants
the climate causes soils to be infertile and unable to support large amounts of vegetation
changes to one part of the ecosystem can have a huge knock on impact on another part e.g. removing vegetation can cause soil erosion
what are the opportunities in the thar desert
tourism —> 500,000 visitors every year
mining —> rajasthan is rich in minerals e.g. limestone
subsistence farming —> farming at a smaller scale and aims to produce food for the farmer and their family
commercial farming —> farming with the intention to sell e.g. wheat and cotton
energy —> energy is produced using solar panels —> energy used to clean water supplies contaminated with salt (desalination) —> clean water
what challenges are the thar desert facing
extreme temperatures —> as high as 50 degrees —> difficult to work and plants/animals needs large amounts of shade to survive
inaccessibility —> limited roads due to low population density
tarmac roads don’t cope well in high temperatures
water supply —> farming and population increase has put pressure on water use
low temp makes water scarce
where is the thar desert located
covers area of 200,000 km^2
stretches across north west india into pakistan
what is desertification
process by which land becomes drier and degraded as a result of climate change or human activities
what are the physical causes of desertification
climate change:
less rainfall - less rainfall in areas that are already dry. this means less plants (plants hold soil together) which leads to soil erosion
higher temperatures - increasing temperatures which causes water to evaporate from ground which kills the plants that holds the soil together
what are the human causes of desertification
over grazing - cattle eat too much vegetation which holds the plants together. soil becomes easily eroded
over cultivation - repeated farming exhausts the soil —> nutrients are used up —> infertile
population pressures - more deforestation fo make space for housing etc —> less roots to hold soil together —> soil erosion
demand for fuel wood - removing trees leaves soil exposed
4 strategies used to reduce desertification
water management
soil management
tree planting
use of appropriate technology
how can water management reduce desertification
switching to growing crops that don’t require as much water to grow e.g. olives
drip irrigation means drip feeding the soil with water rather than over irrigating the soil at once —> this regents soil erosion
how can soil management reduce desertification
leaving areas of land to rest in between grazing or planting let’s them recover their nutrients
compost can be used to add extra nutrients to the soil
how can tree planting reduce desertification
prevent rain from water away nutrients —> prevent soil erosion
how can appropriate technology reduce desertification
involves building lines of stones along contours (area of land that is the same height) —> stones trap soil being transported by the wind so that it is isn’t eroded.
Also, the stone lines reduce the flow of water over the surface of the land which means nutrients not washed away
desert fringes
found at borders of hot deserts
more predictable rainfall here and can support agriculture
fragile environment
salinisation
accumulation of salts in the soil that occur as a result of rapid evaporation of water
where is the sahel located
north africa just under the sahara
what are they doing in the sahel to reduce desertification
green wall
how long is the green wall and how much land does it cover
green wall stretches 7775km and covers a total area of 11.6 million hectares
where does the green wall go from and to
from senegal to djibouti
what does the green wall do
trees along the southern edge of the sahara desert to prevent desert spreading south —> planting trees reduces soil erosion as it intercepts rain —> less nutrients are washed away so more nutrients are provided for plants and crops to grow
why is there desertification happening in senegal and the sahel
declining rainfall, overgrazing and climate change
what impact does the green wall project have on people who live there
creates jobs
prevents spread of desertification
how do stone lines work to help combat desertification
example of appropriate technology —> stone lines (or bunds)
lines of stones along contours (area of land that is the same height) —> trap soil being transported by the wind so that it isn’t eroded
stone lines reduce the flow of water over the surface of the land —> reduce soil erosion —> less nutrients washed away
