AT A GLANCE – tropical rainforests and desert environments

The natural Environment – ecosystems, tropical rainforests, and desert environments Sustainable management – using a rainforest in a way that allows us to take some things from it, but without destroying
the rainforest as a whole, e.g. ecotourism
Ways of managing the rainforest – selective logging (only some trees removed to maintain forest structure); replanting
Ecosystems trees (plant same variety of tree species to maintain variety and trap CO2); ecotourism (allow tourists to visit but in a
Ecosystems controlled way that limits damage and involves local people); International Hardwood Agreements (agreements to not cut
Ecosystem – a system that contains biotic (living, e.g. wildlife) and abiotic (non-living, e.g. down certain trees, e.g. mahogany and teak, e.g. Forest Stewardship Council); education (teach local people about the
water and soil) things long-term impacts of deforestation, help them find other ways of making a living); reducing debt (cancel debt so that LICs
Producers – e.g. plants, found at the bottom of a food chain or ecosystem and normally don’t cut down trees to make money to pay back loans and the interest owed); conservation (set up national parks and
photosynthesise to create energy reserves that restrict damaging activities, e.g. the Amazon Fund)
Consumers – eat other plants/animals (insects, birds, mammals)
Decomposers – break down dead and decaying matter (bacteria, fungi) The Amazon Rainforest, Brazil
Food chain/web – diagram that shows the connections between plants/animals
Location – South America; covering 8 million km2 including parts of Brazil, Peru & Ecuador
Nutrient cycling – the way nutrients move from the soil, to plants, to animals, and then back to the soil again
Rate of deforestation – since 1978, over 750,000km2 has been cut down
Trophic levels – levels at which energy (from the sun) is held in plants/animals
Causes of deforestation – cattle ranching, farming, both subsistence (local scale) & commercial (large
scale), logging, mining, road building, energy (HEP), new settlements; increasing pressure from
Biomes
Brazil’s growing population as it becomes an NEE/HIC
Biome – a large-scale ecosystem that covers countries or continents
Impacts of deforestation – environmental (release of CO2, climate change, soil erosion, reduced soil
Tropical rainforest – on the equator; hot and humid all year round; lots of dense vegetation growing
quality) & economic (increased wealth, mining jobs, BUT people, e.g. rubber tappers, lose jobs)
Grassland (savannah) – between the tropics; dry & rainy seasons; no trees, just grasses
Hot desert – just north/south of the equator; very hot with little rainfall, cold at night; cacti and basic shrubs grow
Deciduous forest – mid latitudes; four seasons (warm summers, cool winters); trees lose leaves in winter; grow back in desert environments
summer First have a look at one of the most famous hot deserts around the world.
Tundra – high latitudes (close to poles); cold winters & brief summers; permafrost; shrubs
are slow growing & low-lying
Polar – at north/south poles; very cold, icy and dry; not much grows at all; growing season
is two months long

Tropical rainforests
Location – on and around the equator, e.g. Amazon (South America) & Congo (Africa)
Climate – warm (20oC – 28oC); high rainfall (around 2000mm a year); rainfall is convectional and
with daily thunderstorms
Soil – few nutrients; trees quickly take up nutrients; nutrients washed out by heavy rain
Layers – forest floor (at the bottom); shrub layer (lowest level vegetation, very dark); under canopy
(vines and lianas grow); canopy (more sunlight, most leaves and animals live here); emergent layer
(tallest trees – 50m high]
Plant adaptations – evergreen (don’t drop leaves at a particular time); buttress roots (to keep tall
trees stable and collect nutrients from shallow soil); drip tips (channel heavy rainfall off leaves);
large leaves (trap sunlight); tall, thin trunks with no lower branches (race to the top to trap
sunlight, no wasted energy on branches lower down)
Animal adaptations – camouflage, e.g. chameleons (hide from predators/prey); strong beaks, e.g. Hot Deserts map
parrots (to break into nuts and seeds); prehensile tails, e.g. spider monkeys (to grip onto branches
in the canopy); amphibious, e.g. frogs & crocodiles (able to exist in water and on land); nocturnal, 1. Great Basin Desert
e.g. bats (use echolocation to find prey in dark) 2. Peruvian Desert
Interdependence – all parts of a rainforest are connected; warm climate helps fast growth; fast 3. Atacama Desert
growth means plants provide food for animals; warmth means fast decomposition, releasing 4. Patagonian Desert
nutrients for quick uptake; high rainfall provides water for growth; trees are water stores and CO 2 5. Sahara Desert
stores; deforestation upsets this balance & releases too much water and CO 2 6. Arabian Desert
Biodiversity – the variety of plants & animals living in a rainforest; Deforestation – the removal of trees 7. Turkestan Desert
Causes of deforestation – increasing populations (land needed for housing); mining (gold, iron ore); energy (HEP dams on 8. Great Indian Desert
the large rivers); logging (wood, e.g. mahogany, or rosewood, for fuel or furniture); farming (cattle or soya) 9. Gobi Desert
Environmental impacts – loss of species, possible extinctions, soil exposed and washed away, nutrients lost from soil
10. Kalahari and Namib Desert
leaching, increased CO2 into the atmosphere (global warming)
Note – If you notice carefully, major hot deserts having extremely high temperatures are found near the Tropic of
Social impacts– people get jobs in new industries and have a better life than in the city;
Cancer and Tropic of Capricorn.
BUT native tribes may be moved off their own land, or may catch diseases from outsiders
Economic impacts – workers make lots of money from jobs, less money spent on energy as World’s largest hot desert is Sahara which covers almost the whole continent.
HEP used instead; BUT setting up new industries and HEP stations may cost a lot With an extreme climate hot deserts have very challenging environment for living beings. You will hardly any kind
Value of the rainforest – goods (paper, wood, cocoa, coffee, medicines, palm oil); services of vegetation there. Only few plants and animals have adapted to live in this climate.
(cleans the atmosphere, stores CO2, habitats for animals, biodiversity)
Climate of the hot desert
 Climate is extremely hot and temperature remains more than 40 degrees for most time of the day.
However, the hot desert become cold as the temperature falls below 0 degree.
 Climate is very dry with negligible humidity. The average rainfall is 250 mm a year.
Soil
 Thin, sandy, rocky and grey are the terms to describe the soil of the desert. Since it is very dry, it soaks
the rainfall quickly
 The crusty look of the surface is due to the lack of water in the soil. Due to high temperature the water
under the surface rises up through evaporation and leave salts behind on the surface.
Plants in Hot Deserts
Most people would associate the desert with cacti and short bushes, which is definitely the reality of the plant life
that can be found there. The plants that are in deserts are specially adapted to cope with very little rainfall and a
lot of them have short life cycles. This means that they only grow when it rains.
Animals in Hot Deserts

Some mammals cope very well in the desert, but they tend to be very small and a lot of them are also nocturnal.
This means that they do not have to cope with the extreme temperatures during the day, but they do have to cope
with the cold at night. A lot of the birds that live in the desert leave the area when the temperature becomes too
extreme.

People in Hot Deserts

Humans who live in the desert usually grow crops to sustain themselves, but they need to be near natural springs
and wells in order to do this. Most of these bodies of water can be found along the very edge of the desert.

There are also indigenous people who call the desert their home, but they tend to be nomadic. They take herds of
sheep and goats across the desert in search of food and water. This means that they cannot stop in one place for
too long.

Plants in Hot Deserts

The Climate in Hot Deserts
If we take a look at some of the plants that can be found in deserts, then we can see that a lot of them have long
Deserts are generally thought of as being places where very little rain falls. But, when rain does fall, it can vary a
roots or roots that are spread out. Plants with long roots can reach sources of water that can be found deep
lot. You might only see rainfall once every several years in a desert. This is very extreme and it has led to a lot of
underground, while plants with wide roots can catch a lot of water when it does rain.
plants in the desert having short life cycles that are prompted by rainfall. The temperatures in the desert are also
extreme, being very hot during the day and very cold at night.

Animals in Hot Deserts

The animals that can be found living in the desert are worth paying attention to, because they are specially
Desert Ecosystems
adapted to live there. They have to be able to thrive in such a harsh environment. When most people think about
If you have not learnt about ecosystems, then you should take a look at our page that covers the topic.
animals in the desert, they think about reptiles and insects.

In deserts, ecosystems are incredibly fragile. One simple change could affect a whole ecosystem. But, ecosystems
in the desert have a lot of different things to content with. For example, the amount of rain that falls in a hot
desert is very low. This means that animals have to keep moving to find water, or they have to be adapted to cope
with very little water.

The people who live in deserts can also negatively impact ecosystems because of the way that they water the land
that their crops grow on. Most of the time, this involves taking unsustainable amounts of water from underground.
Naturally, this means that there is less water for the plants and animals who also rely on those sources.
 erosion though!
Desertification
While a lot of the plants and animals in hot deserts are specially adapted to live there, there are still a lot of
You can also go on camel safaris to see the beautiful sites and even stay with a
problems that you need to be aware of. Desertification is probably the biggest problem in the desert because it
Bedouin tribe in a tent! This is more sustainable. 
involves land degrading, meaning that it becomes less productive.

One of the key aspects of desertification is soil erosion. This means that soil can easily be removed in layers by
gusts of wind and water. This leads to nutrients being lost and soil becoming less productive quickly, making it Challenges of Extreme Average daytime temperatures in the Sahara are over 40’C for months at a time
difficult to grow anything on it. development temperatures in the summer and are over 30’C for most of the year. This creates problems for
in this people in the desert and means that more water is needed for hydration etc.
environment.
At these temperatures, tarmac roads can melt and machinery may not work
Reducing the Risk of Desertification
effectively.
There are plenty of different things that can be done to reduce the risk of desertification, they include:
Water supply By it’s nature, the desert has very low rainfall <250mm per year. This causes
problems on oilfields for example with large numbers of people. Water has to
 By planting trees, people can prevent soil erosion. This is because the trees will act as windbreaks and
pumped from underground which is expensive and these supplies may be
prevent the wind from blowing away the top level of soil. Trees can also be used to provide crops and
depleted (go down).
animals with shade, reducing the temperatures that they are exposed to.
To reduce soil erosion, land that is used for agricultural purposes should occasionally be left to rest. This allows the
In farming areas, water supplies may run low and soils may become too salty as
soil to recover nutrients that would otherwise cause the land to become unproductive remote locations)
water is evaporated leaving salts behind. This means that crops do not grow
Hot Desert Case Study – Sahara Desert well.

Where In North Africa. Inaccessibilit In the desert there are very few roads as so few people live there. Where there
y = difficult to are roads, tarmac can melt in the heat and roads may be buried by
What The Sahara is the largest hot desert in the world at 9.4 million km2. get there, sandstorms.
difficult to
The Sahara covers many different countries (Algeria, Morocco, Egypt, Sudan, Tunisia etc.) get around Oil from oil fields in Algeria has to piped hundreds of kilometres across the
desert. This adds cost and creates the possibility of damaging oil spills.

Opportunities Mineral In Algeria oil and gas make up half the country’s GNI!
for extraction
development. The Hassi Messaoud Oilfield is deep in the desert and employs 40,000 people!

Energy See above for oil and gas.

Also work has begun on Algeria’s first solar power plant. Large areas of solar
panels will take the sun’s energy and convert it to electricity. There are plans to
export this energy to Europe via cables running under the Mediterranean Sea.
By 2030, 40% of energy in Algeria is expected to come from renewables, eg
solar.

Farming Egypt is hot and dry. Population has increased by nearly 300% over the last 25
years!

Farms in the Nile Valley use water from the river and from underground to
water crops to provide for the population and for export to raise the GNI
(salad, fruits...) 

BUT – as water evaporates the soil is becoming salty 

Tourism In Morocco, you can go on 4x4 trips around the desert – this can cause soil