✅desert

Question 1

biodiversity

Answer 1

variety of plants and animals in a particular ecosystem

Question 2

what is a hot desert

Answer 2

an area of dry land —> less than 250mm of rainfall per year

temps up to 50 degrees

Question 3

where are hot deserts found

Answer 3

30 degrees north and 30 degrees south of the equator

Question 4

what is climate like (temp and precipitation)

Answer 4

temperature
up to 50 degrees during the day and below 0 degrees at night

precipitation
less than 250mm of rainfall per year

Question 5

why is it hot and dry in deserts

Answer 5

hot —> close to the equator where sun rays are more concentrated

dry —> in areas of high pressure where air is sinking

Question 6

what is the soil like in a hot desert

Answer 6

dry

coarse texture

infertile

Question 7

what plants and animals would you find in a hot desert

Answer 7

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

Question 8

how have animals adapted to hot deserts (camels)

Answer 8

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

Question 9

how have animals adapted to the desert (emu)

Answer 9

unique double quilled feather that protect them from heat

Question 10

how have plants adapted to hot deserts (cacti)

Answer 10

spines to deter predators

thick, waxy skin to reduce water loss

stems that store water

Question 11

what is biodiversity like of hot deserts

Answer 11

limited due to extreme weather

this means any changes can have drastic consequences

global warming is the biggest threat to hot dexter’s biodiversity

Question 12

why are hot deserts an interdependent ecosystem

Answer 12

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

Question 13

what are the opportunities in the thar desert

Answer 13

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

Question 14

what challenges are the thar desert facing

Answer 14

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

Question 15

where is the thar desert located

Answer 15

covers area of 200,000 km^2

stretches across north west india into pakistan

Question 16

what is desertification

Answer 16

process by which land becomes drier and degraded as a result of climate change or human activities

Question 17

what are the physical causes of desertification

Answer 17

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

Question 18

what are the human causes of desertification

Answer 18

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

Question 19

4 strategies used to reduce desertification

Answer 19

water management
soil management
tree planting
use of appropriate technology

Question 20

how can water management reduce desertification

Answer 20

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

Question 21

how can soil management reduce desertification

Answer 21

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

Question 22

how can tree planting reduce desertification

Answer 22

prevent rain from water away nutrients —> prevent soil erosion

Question 23

how can appropriate technology reduce desertification

Answer 23

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

Question 24

desert fringes

Answer 24

found at borders of hot deserts

more predictable rainfall here and can support agriculture

fragile environment

Question 25

salinisation

Answer 25

accumulation of salts in the soil that occur as a result of rapid evaporation of water

Question 26

where is the sahel located

Answer 26

north africa just under the sahara

Question 27

what are they doing in the sahel to reduce desertification

Answer 27

green wall

Question 28

how long is the green wall and how much land does it cover

Answer 28

green wall stretches 7775km and covers a total area of 11.6 million hectares

Question 29

where does the green wall go from and to

Answer 29

from senegal to djibouti

Question 30

what does the green wall do

Answer 30

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

Question 31

why is there desertification happening in senegal and the sahel

Answer 31

declining rainfall, overgrazing and climate change

Question 32

what impact does the green wall project have on people who live there

Answer 32

creates jobs

prevents spread of desertification

Question 33

how do stone lines work to help combat desertification

Answer 33

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