Unit 1- Geography- 1B

• an ecosystem is a unit that includes all the biotic (living) parts and the abiotic (non-living) parts in an area
• organisms in ecosystems can be classed as producers, consumers, or decomposers
• a producer is an organism that uses sunlight energy to produce its food.
• a consumer is an organism that gets its energy by eating other organisms- it eats its producers or other consumers
• a food chain shows what eats what.
• a food web shows lots of food chains and how they overlap
• a decomposer is an organism that gets it energy by breaking down dead material (dead producers, dead consumers, or fallen leaves
• bacteria and fungi are examples of decomposers
• when the dead material is decomposed nutrients are released into the soil, which is taken up from the soil by plants- this is the transfer of nutrients called NUTRIENT CYCLING

• the climate in an area determines what type of ecosystem forms
• POLAR- found around the north and south poles, they are very cold, icy and dry.
• HOT DESERT- found between 15* and 30* north and south of the equator where there's little rainfall. it's very hot during the day and very cold at night
• TROPICAL RAINFOREST- found around the equator, between the tropics, where it's hot and wet all year round. this is an area of lush forest, with dense canopies of vegetation forming a distinctive layer

• tropical rainforests are hot and wet all year round
• temperature is generally between 23*-28*C- this is because tropical rainforests are near the equator, the sun is overhead all year round
• rainfall is very high around 2500 mm per year
• the soil isn't very fertile as heavy rainfall washes nutrients away
• there are nutrients at the surface due to decayed material such as fallen leaves, but this layer is very thin as decay is fast in the warm, moist conditions.
• plants- many trees are very tall and the vegetation cover is dense- very little light reaches the forest floor
• there are lots of epiphytes (plants that grow on other living plants and take their nutrients and moisture from the air)

• the warm wet climate means that dead plant material is decomposed quickly by bacteria and fungi on the forest floor. this makes the surface soil high in nutrients, meaning plants can grow quickly and easily
• plants pass on their nutrients when they are eaten by animals, the dense vegetation provides lots of foods, so animal populations are high. many plant and animal species have formed symbiotic relationships (where they each depend on the other for survival)
• trees intercept and take up lots of water, and release it back into the atmosphere, providing moisture for further rainfall. deforestation means that the climate may change, and the risk of drought increases, affecting the plants and animals that live in the ecosystem
• biodiversity is the variety of organisms living in a particular area- both plants and animals
• rainforests have extremely high biodiversity- they contain around 50% of the world's plant, animal and insect species, and may contain around half of all life on earth
• rainforests are stable and productive environments because it's hot and wet all year round. plants and animals don't have to cope with changing conditions and there is always plenty to eat
• many organisms have evolved to depend on just a few species for survival

• plants and animals have adapted to the physical conditions
• plants are adapted to cope with the high rainfall, high temperatures and competition for light
• tall trees competing for sunlight have big roots called BUTTRESS ROOTS to support their trunks
• plants have thick, waxy leaves with pointed tops. the pointed tips(called drip-tips) channel the water to a point so it runs off- that way the weight of the water doesn't damage the plants, and there's no standing water for fungi and bacteria to grow in. the waxy coating of the leaves also helps repel the rain
• many trees have smooth, thin bark as there is no need to protect the trunk from cold temperatures. the smooth surface also allows water to run off easily.
• the rainforest has 4 distinctive layers of plants with different adaptations. the highest layer (emergents) only have branches at their crown (where most light reaches them), and plants in the under canopy have large leaves to absorb as much light as possible
• climbing plants, such as lianas, use the tree trunks to climb up to the sunlight
• plants drop their leaves gradually throughout the year, meaning they can go on growing all year round

• many animals spend their entire lives high up in the canopy. they have strong limbs so that they can spend all day climbing and leaping from tree to tree (howler monkeys)
• some animals have flaps of skin that enable them to glide between trees (flying squirrels). other have suction cups for climbing (red-eyed tree frogs)
• some birds have short, point wings so that they can easily manoeuvre between the dense tangle of branches in the trees (the harpy eagle has a short wingspan)
• some animals are camouflaged(leaf-tailed gekos), they look like leaves so they can hide from predators
• many animals are nocturnal (active at night) (e.g. sloths). they sleep through the day and feed at night when it's cooler- this helps them to save energy
• some animals are adapted to the low light levels on the rainforest floor (anteaters, they have a sharp sense of smell and hearing, so they can detect predators without seeing them)
• many rainforests animals can swim (Jaguars). this allows them to cross river channels

• population pressure- as the population in the area increases, trees are cleared to make land for new settlements
• commercial logging- trees are felled to make money. road building for logging also requires more clearance
• commercial farming- land is cleared to make space for cattle grazing, or for huge palm oil or soya plantations
• energy development- building dams to generate hydro-electric power floods large areas of forests
• mineral extraction- minerals are mined and sold to make money (gold and iron)
• subsistence farming- land is cleared so farmers can grow food for themselves and their families

• ENVIRONMENTAL:
• with no trees to hold the soil together, heavy rain washes away the soil (soil erosion). this can lead to landslides and flooding.
• without a tree canopy to intercept (catch) rainfall and tree roots to absorb it, more water reaches the soil. This reduces soil fertility as nutrients in the soil are washed away, out of reach of plants.
• trees remove CO2 from the atmosphere. also burning vegetation to clear forest produces CO2. So deforestation means more CO2 in the atmosphere which adds to the greenhouse effect.
• deforestation is responsible for at least 15% of global CO2 emissions each year- more than all of the world's annual transport emissions combined

• ECONOMIC:
• logging, farming, and mining create jobs
• a lot of money is made from selling timber, mining and commercial farming
• in the long term, deforestation can destroy the resources the countries depend on, e.g. tinder, and reduce the attractiveness of the area to tourists
• the livelihoods of some local people are destroyed- deforestation can cause the loss of the animals and plants that they rely on to make a living

The rate of Deforestation is changing

• the rate of rainforest deforestation is very high- roughly 130 000 km2 per year
• globally, the rate seems to be slowing down but there are still hotspots where the rate of deforestation is increasing, e.g. Borneo and Nigeria
• overall, the deforestation in Brazil and Indonesia accounted for almost half of the global total between 2001 and 2014, though Brazil has reduced its deforestation rate since 1990.

• The Amazon is the largest rainforest on Earth- covering an area of around 8 million km2, including parts of Brazil, Peru, and Columbia.
• Since 1978, over 750 000 km2 has been destroyed by deforestation
• population growth and migration to the area is also putting pressure on the Amazon rainforest, especially as the Brazilian government offers land in the rainforest to poor people from overcrowded cities.
• there are many more small-scale subsistence farmers now, and people who have no land or whose land has become unproductive are opening up more areas of the forest

• ENVIRONMENTAL:
• the Amazon stores around 100 billion tonnes of carbon- deforestation will release some of this as carbon dioxide, which causes global warming
• Brazil is losing 55 million tons of topsoil every year because of soil erosion caused by soy farming. 
• ECONOMIC:
• economic development has brought wealth to countries that were very poor
• farming makes a lot of money for the countries in the rainforest, e.g. in 2008, Brazil made 6.9 billion $s from trading cattle
• brazil is also the world's second-biggest exporter of soybeans
• the mining industry creates jobs for loads of people- lots of jobs available
• logging contributes a huge amount to Brazil's economy
• local Brazilian rubber tappers who extract natural rubber from rubber trees have lost their livelihoods as trees have been cut down.

• it's important to protect the rainforest, in order to preserve its biodiversity- maintaining the high diversity of plants and animals is valuable to both people and the environment
• many products including rubber, coffee, chocolate, and medicines are sourced from the rainforest. if species become extinct, the change to discover new medicines and develop new products is reduced.
• sustainable development also allows for long-term economic benefits e.g. through developing ecotourism
• protecting the rainforests may help reduce the greenhouse effect, by reducing co2 emissions, and allowing the trees to continue absorbing co2.
• some of the impacts of rainforest destruction e.g. climate change could affect all countries, not just the countries where the deforestation is happening
• rainforests also help regulate the climate and water cycle- without them the risks of drought and flooding in certain areas can increase

• only some trees (older/ inferior ones) are felled- most trees are left standing- this less damaging to the forest than felling all the trees in an area. if only a few trees are taken from each area the overall structure of the forest is kept- the canopy is still there and the soil isn't exposed. this means the forest will be able to regenerate so it can be used in the future
• the least damaging forms are 'horse logging' and helicopter logging'- dragging felled trees out of the forest using horses or removing them with helicopters instead of huge trucks

• this is when new trees are planted to replace the ones that are cut down
• this means there will be trees for people to use in the future
• it's important that the same types of trees are planted that were cut down so that a variety of trees is kept for the future
• in some countries, there are laws to make logging companies replant trees when they clear an area

• ecotourism is tourism that minimises damage to the environment and benefits the local people
• only a small number of visitors are allowed into an area at a time. environmental impacts are minimised, e.g. by making sure waste and litter are disposed of properly to prevent land and water contamination
• ecotourism provides a source of income for local people, e.g. they act as guides, provide accommodation and transpor. it can also raise awareness of conservation issues bring in more money for rainforest conservation
• if local people are employed in tourism, they don't have to log or farm to make money, meaning fewer trees are cut down. if a country's economy relies on ecotourism, there's an incentive to conserve the environment
• ecotourism has been very successful in Costa Rica. it is the largest source of income for the country and has led to 21% of the country being protected from development

• hardwood is a general term for wood from certain tree species, e.g. mahogany and teak. the wood tends to be fairly dense and hard- it's used to make things like furniture
• high demand for hardwood from consumers in richer countries means that some tropical hardwood trees are becoming rarer as people are chopping them down and selling them
• there are international agreements in place to try to reduce illegal  logging and promote hardwood from sustainably managed forests
• The FOREST STEWARDSHIP COUNCIL is an organisation made up of businesses, non-governmental organisations and individuals from all over the world.
• they mark sustainably-sourced timber products with their logo so that consumers can choose products that are not contributed to unsustainable deforestation.

• a lot of tropical rainforests are in lower-income countries
• lower income countries often borrow money from wealthier countries or organisations to fund development schemes or cope with emergencies like floods
• this money has to be paid back with interest
• these countries often allow logging, farming, and mining in rainforests to make money to pay back the debt
• so reducing debt means countries don't have to do this and the rainforests can be conserved for the future
• debt can be canceled by countries or organisations, but there's no guarantee the money that would have been spent on repayments will be spent on conservation instead
• a better solution is conservation swap, where part of a country's debt is paid off in exchange for a guarantee that the money is spent on conservation

• education of the international community about the impacts of deforestation can encourage people to buy products that are certified from sustainably managed sources
• some local people don't know what the environmental impacts of deforestation are. local people try to make money in the short term to overcome their own poverty (illegal logging).
• educating local people about the impacts of deforestation and ways to reduce the impacts decreases damage to the rainforest environment.
• also, educating local people about alternative ways to make money that don't damage the environment as much, e.g. ecotourism, means they aren't dependent on unsustainable options in order to make a living.

• many countries have set up national parks and nature reserves within rainforests. in these areas damaging activities, e.g. logging, are restricted. however, a lack of fund can make it difficult to police the restrictions
• as a result, some countries have set up funds which overseas governments and businesses can invest in. the countries get the money in exchange for rainforest conservation
• the money can be used to enforce restrictions on damaging activities and to promote sustainable use of the rainforests