Tropical Rainforests Geography: 6.x
What are the forest clearing activities causing deforestation in the rainforest?
-COMMERICAL FARMING: CATTLE -COMMERCIAL FARMING: CROPS -ROAD BUILDING -SETTLEMENT & POPULATION GROWTH
What are examples of some animal survival strategies?
-Camouflage used by prey to escape predators & by predators to catch prey -Poisonous animals often brightly coloured to warn predators to leave them alone, e.g. multiple species of arrow frogs.
How does energy development cause deforestation in the rainforest?
-Dams built for HEP due to vast water & ideal river conditions, meaning huge areas flooded to make dams -Submerged forest rots, making acidic water & corroding turbines, and turbines also blocked by soil washed off in heavy rain, so dams have short life.
What characterises the ground layer?
-Dark, due to vegetation blocking light (only 2% light penetrates) -Hot, so steamy -Decomposers decay dead organic matter, e.g. rotting leaves -Infertile soil due to rapid uptake of nutrient by plants
What are problems with government management of the rainforest?
-Few govs. are willing to do anything that could slow rates of economic development, e.g. citizens want better living standards more than new nature reserves. -Corruption can occur, e.g. illegal logging & developers paying bribes
How do plants survive in competition for sunlight?
-Flexible leaf stems allow leaves to move with sun & maximise photosynthesis -Dense vegetation of rainforest shows 4 distinct layers & in each one, plants have adjusted to physical conditions (particularly available sunlight). -Shading effect means highest trees get most light, but plants in lowest layer rely on other ways to get food instead of photosynthesis, e.g. from soil or parasitic plants attach to host & share its food/ water.
What rainforest goods do we get from plants?
-Food and spices, e.g. bananas, cocoa, sugar, cinnamon & vanilla -Useful products like rubber, rope and baskets -Chemicals used in perfumes, soaps, polishes and chewing gum (from the leaves, flowers & seeds)
How does commercial farming (crops) cause deforestation in the rainforest?
-Forest is cleared to give space to plantations for bananas/ palm oil/ pineapple/ sugar cane/ tea/ coffee/ soy bean -Most clearance in Amazonia due to Soy Bean & amount cleared for this doubled 1990-2010 -Soil doesn't sustain crops for long & so again like cattle it's unsustainable -Sugar cane also grown as a biofuel
What are global impacts of deforestation?
-Global Warming: Felling trees mean less CO2 absorption & fire used in clearance releases carbon stored in wood back to the atmosphere. It contributes to greenhouse effect, threatening survival of human race as well as rainforest. Brazil is 4th largest CO2 emitter & 75% of emissions of this come from deforestation. -Biodiversity loss: Biodiversity reduced & individual species endangered/ extinct by loss of habitats & increased CO2 emissions. Roughly 137 plant, animal & insect species lost daily due to deforestation (50,000 per yr). Amazon could lose 30-45% of main species by 2030. Disease cures disappear along with species.
What are rainforest goods? + What are rainforest services?
-Goods are things that can be obtained directly from the rainforest. -Services are benefits the rainforest can offer to both people & environment
What will reduce global warming (linked to rainforest)?
-Great reduction in fossil fuels burnt, lowering CO2 emissions -Great reduction in deforestation, increasing CO2 absorption by leaves- SO TROPICAL RAINFOREST HAS CRITICAL ROLE AS ONE OF LARGEST CARBON SINKS WORLDWIDE
Why is there such rich biodiversity in tropical rainforests?
-Hot & humid climate all yr around combing with convectional rainfall -Excellent nutrient cycling -Rainforest's layer structure
Where are rates of deforestation increasing?
-Asia (Indonesia, Malaysia & Thailand): in Indonesia rate doubled 2005-2010 compared to 2000-2005 -Africa (Madagascar & Mali) -S America (Peru, Guatemala & Bolivia): in Peru rate almost doubled 2005-2010 compared to 2000-2005
Where does deforestation in Brazil mainly occur?
-At ACCESS POINTS: rivers & cities on the coast, e.g. S of Amazon cleared as access from Rio de Janiero, Sao Paulo & Brasilia.
Where are rates of deforestation decreasing?
(Decreased but STILL OCCURS): Cameroon, Nicaragua, Senegal, Brazil, Cambodia, Laos & Mexico.
What characterises the emergent layer?
-Big buttress roots supports tallest trees -Birds & butterflies -Lots of sunlight -45+m high
What are examples of rainforest services that benefit people?
-Biodiversity and wildlife habitats can be enjoyed by everyone (natives or tourists) -Air purification (most valuable locally and globally)
What are statistics for the scale of deforestation impacting the rainforest recently?
-62 countries have TR within their borders, but around 1/2 world's tropical rainforest has been cleared -Indonesia has 3rd largest amount of TR worldwide, but rate of deforestation increased by 107% from 2000-2010
What feature does water bring to tropical rainforests?
-Abundant water feeds huge rivers that are impressive features of TRs, e.g. Amazon in Brazil & Congo in Central Africa
What are examples of rainforest services?
-Air purification (CO2 absorption) -Water & nutrient cycling -Protection against soil erosion -Wildlife Habitats -Biodiversity -Employment opportunities -Tourism/ Leisure
How does settlement and population growth cause deforestation in the rainforest?
-All activities require workers, with families, that all need homes & services -Forests cleared for settlements & services
What are the main areas of tropical rainforest?
-Amazon Basin (Brazil)- largest area of TR -Central Africa -SE Asia
How does illegal trade in wildlife cause deforestation in the rainforest?
-Hunting, poaching & trafficking of wildlife still big business in Brazil, and although not direct cause of deforestation, it endangers species, upsets natural balance & degrades rainforest ecosystem
What can be done to manage the rainforest on an international level?
-Inter-government agreements on hardwoods and endangered species: E.g. International Tropical Timber Agreement (2006) restricts trade in hardwoods taken from TR, as only sustainably felled hardwoods may be taken. It stops illegal felling occurring in remote areas unnoticed by officials. -Debt reduction by HICs: LICs/NEEs containing rainforest have large debts from overseas loans, so HICs can do debt reduction, e.g. Debt-for-nature swap between USA and Brazil, who agreed to convert debt of £13.5million to fund to protect large areas of TR in 2010. -Conservation & education by NGOs: NGOs e.g. WWF rely on volunteers & donations as they're charities, and promote conservation message largely through education, and buy up threatened areas & make nature reserves.
How is a strangler fig adapted to the rainforest?
-It takes nutrients from the host as can't get much underneath the canopy. -It's branches grow taller to catch sunlight -It climbs up the tree it attaches to, to get sunlight as it's difficult for plants & seedlings to grow on forest floor, with poor soil & competition for water/ nutrients.
How is a teak tree adapted to the rainforest?
-It's deciduous (sheds leaves in dry season) so it's protected from water loss -Leaves & branches spread out as much as possible to get max. light -Long straight trunk allowing water to run down as quickly as possible & tall to reach sunlight -Wide buttress roots support base of tree in triangular shape, stopping it toppling in high wind.
How does logging cause deforestation in the rainforest?
-It's the first step in clearing land for other uses. -Selective logging may occur where companies pick certain trees & sell them to make products, e.g. Timber companies pick Mahogany & Teak and sell them to make furniture. -Smaller trees are used as wood/ fuel/ made into charcoal/ made into pulp -Clear felling may occur where vast areas are cleared in 1 go
What are the resource exploiting activities causing deforestation in the rainforest?
-LOGGING -MINERAL EXTRACTION -ENERGY DEVELOPMENT -ILLEGAL TRADE IN WILDLIFE
How does commercial farming (cattle) cause deforestation in the rainforest?
-Large areas of Amazon cleared for livestock & cattle rearing estimated to cause 80% of TR destruction in Brazil -Land can't be used for long as pasture quality declines quickly, then farmers have to move on to destroy more TR, so it's very unsustainable (especially in comparison to the way indigenous tribes slash & burn)
What characterises the continuous canopy layer?
-Lianas (vines) & epiphytes (grown on tree trunks) -Birds & animals -Shades light below -25-40m high
What have indigenous tribes in Brazil been able to do for years until now?
-Live in harmony with the rainforest by: -Harvesting fruit/nuts -Cutting wood for fuel -Using timber to build -Discovering illness cures -Clearing small areas by slash & burn
What are local impacts of deforestation?
-Local climate change -Increased soil erosion & fertility decline -River pollution -Decline of indigenous tribes -Conflicts
What can be done by national governments to manage the rainforest?
-Making protected areas/ reserves -Stopping abuse of rainforest & other biomes by developers -Making subjects, e.g. ecology or environmental studies, a compulsory part of school curriculum All these contribute to a better balance between protection & development in the tropical rainforest
What does protecting the rainforest require?
-Making sure much of TR remains untouched, so stays prisitine, e.g. turning large areas of rainforest into nature reserves/ national parks -Allowing resources (goods & services) to be used, but only sustainably
How does mineral extraction cause deforestation in the rainforest?
-Minerals needed by developed countries can be found in tropical rainforests, e.g. gold in Amazon, where 10,000 hectares were used for this in 1999, but now over 50,000 hectares used. -Clear felling means TR suffers badly -Bauxite (Al ore) also extracted from TR
What are examples of rainforest goods?
-Native food crops, e.g. Fruit, Brazil Nuts -Wild meat & fish -Building materials, e.g. Timber -Energy from HEP -Water -Medicines -Rubber & Manufactured goods
How does the rainforest help with medicine?
-Pharmaceutical companies find plants with ingredients to help treat & cure diseases -Indigenous tribes use plant parts (barks, resins, roots & leaves) in trad. cures -Currently over 120 prescription drugs come from plant sources & over 1/4 drugs used are derived from rainforest ingredients. -25% of active ingredients in today's cancer-fighting drugs come from organisms found only in rainforest.
What are main inputs, transfers & outputs in the tropical rainforest ecosystem?
-Rain & sunlight are main inputs -People & animals take nutrients from plants -Animals dying/excreting return nutrients to soil -Nutrient leeching looses nutrients to the ecosystem
How do plants survive rainforests' poor soils?
-Rapid nutrient cycling through the ecosystem -Absorption of sunlight, so able to photosynthesise -Warm, humid climate is ideal for plant growth throughout yr -Ability of plants to adapt as they compete for sunlight & nutrients
How can mining be made less destructive to help deforestation?
-Replacing top soil removed originally to get at bauxite afterwards, and then replanting native trees makes it less destructive.-Most reforestation is $2,500 per hectare, or 7% of mine's cost
What is vegetation typical of a tropical rainforest?
-Rich vegetation cover as despite poor soils, very good nutrient cycling occurs. -Tall trees (30-45m), e.g. Mahogany trees -Vines
How does road building cause deforestation in the rainforest?
-Road building needed to bring equipment & transport products to markets. -It cuts through rainforest & gives access to exploiters of resources E.g. Trans-Amazonian Highway began construction in 1972 & is 4000km. It's opened up remote areas of TR
What characterises the shrub layer?
-Smaller plants with little light -Ground animals, e.g. alligators, ants, jaguars, tarantulas -Dense vegetation in clearings/ opening as more light -0-5m high
What are soils typical of a tropical rainforest?
-Thin & poor (but nutrient cycling allows vegetation). -Biomass (living vegetation & animals) & litter (dead wood/ leaves/ animal remains on ground)store nutrients -Warm, humid conditions make litter decompose, so nutrients become part of soil, but water (from heavy rain) washes away most nutrients before they get to soil, hence poor soils. -Plants still get enough nutrients to survive & many nutrients are stored in large, thick trees.
How is an elephant adapted to the rainforest?
-Trunk to search for food on ground & high branches -Ears to keep them cool, as flapping them can lose up to 5°C because heat is released from capillaries close to the surface -Travel in herds for protection & can group together to protect young -Communication by hunting, growling & trumpeting. Infrasounds (to low to be audible to humans) used & important to alert herd of danger -Go through 6 sets of teeth in lifetime, as fibrous plants & constant chewing wears them down -Tusks strip down bark & bore into groundwater, also dig to uncover salts & minerals vital to diets
What is the typical climate of a tropical rainforest?
-Warm & wet, due to close proximity to equator -Little seasonal variation with av. temps. at roughly 26 degrees C & annual rainfll usually exceeding 2500mm.
What are examples of rainforest services that benefit the environment?
-Water & nutrient cycling -Soil erosion protection -Air purification (most valuable locally and globally)
What characterises the under canopy layer?
-Young trees grow quickly in competition for light, and so lots of trees of different ages & sizes -Insects, sloths & howler monkeys -15-25m high
What is the rate of global deforestation?
1 hectare cleared per sec (roughly 31 million hectares per yr)
Give stats. about the change in deforestation in Brazil in recent years.
1. Brazil has largest area of rainforest worldwide & rates of deforestation have fallen to record low, with remaining forest having a type of protected status 2. 20% of Amazon Rainforest has been cleared since 1970 (761,000 square km- 3x size of UK)
What are the main layers of the tropical rainforest? (in order tallest to lowest)
1. EMERGENT 2. CONTINUOUS CANOPY 3. UNDER CANOPY 4. SHRUB LAYER 5. GROUND LAYER
Give 2 statistics about the tropical rainforest's biodiversity.
1. More than 2/3 of the world's plant species found in tropical rainforests. 2. Roughly 1/2 the world's animal species found in tropical rainforests.
What are the 2 groups of resources & opportunities provide by the rainforest? + which drives much of current deforestation?
1. Those given by rainforest in natural state 2. Those given by land once cleared of forest cover (the vast commercial value of this group drives much of current deforestation)
What are 2 main ways tropical rainforests are exploited?
1. Using resources, e.g. timber, water & minerals 2. Clearing forest to make way for other activities, e.g. growing crops & rearing livestock
What is an example of the benefits of ecotourism?
3 Eco Lodges set up in Peruvian rainforest for tourists & rainforest trips. Incomes in local village almost doubled due to lodges & many locals have jobs in the business.
How much of earth's land surface do tropical rainforests occupy?
7%, but they contain many useful resources & are valuable in tackling global warming.
How can some animals avoid competition for food?
By being specialised & living off a specific plant/animal that few others eat, e.g. parrots & toucans have strong beaks to crack open hard nuts.
How is soil erosion & fertility impacted by deforestation?
Clearing forest for resources/ agriculture exposes soil & top soil's quickly removed by heavy rainfall in SOIL EROSION. Soil loses fertility & can silt up river courses. Decline in soil fertility means pastures & plantations abandoned, then more areas cleared, restarting process
What is interdependence made up of in tropical rainforests?
Climate (rain & sunlight), soil, vegetation (trees & plants) and animals interact, making interdependence. Indigenous tribes can also live in harmony with the rainforest ecosystem, living sustainable off its natural resources.
How are conflicts caused by deforestation?
Conflicting views on rainforest mean disputes arise, e.g. between indigenous tribes & loggers, or conservationists & developers, often arguing over value of environment against money.
What may occur due to human use of the rainforest (not deforestation)?
FOREST DEGREDATION, where the forest ecosystem is changed negatively & supply of resources declines.
What can be done at a local level to manage the rainforest?
For areas already being logged/ logged: -SELECTIVE LOGGING: Felling only mature trees, and letting younger grow to avoid soil erosion -STOPPING ILLEGAL LOGGING: Remoteness of rainforest areas means illegal logging can easily occur & it still occurs on a large scale. Satellites and drones now monitor this -AGROFORESTRY: Crops & trees combined by allowing crops to grow in controlled, cleared areas. -REPLANTING: Recreating forest cover by getting seeds of remaining forest, growing them in nurseries, and planting saplings back in deforested areas. For areas untouched by logging: -ECOTOURISM: Scenery, wildlife remoteness & culture attract tourists, who are educated by trip, and profits stay in local community, whilst ecological impact reduced. -BIOSPHERE RESERVE: Forest left untouched except research & plant breeding. Protected core area surround by buffer zone where only specific human activities allowed.
How does the hot & humid climate all yr around combing with convectional rainfall contribute to biodiversity in the tropical rainforest?
High insolation in the sun at the equator means hot & humid climate, and convectional rain comes from warm air rising, cooling, then condensing to form clouds at the equator. Water & sunlight are therefore readily available to encourage biodiversity.
How can human exploitation reduce/ damage tropical rainforest biodiversity?
Human exploitation of resources reduces rich biodiversity, as species get endangered & eventually extinct. Biodiversity loss can cause ecosystem productivity to decline. Tourism can both damage or raise awareness of issues. Even indigenous tribes are now threatened of not being able to live in harmony with the rainforest.
How does the rainforest's layer structure contribute to biodiversity in the tropical rainforest?
Layer structure of the rainforest means there are many more habitants and a higher biodiversity.
Give a stat. showing the opportunity for medicine & cures in the rainforest.
Less than 1% of TR's plants have been tested & well over 100 pharmaceutical companies now research plant cures/drugs compared to 0 companies doing this in 1980.
How is river pollution impacted by deforestation?
Mercury used to separate gold from ground in mining can enter rivers, poisoning fish & people in nearby towns. Soil erosion also pollutes rivers. E.g. in Brazil, in 2015, dam at iron ore mine burst, killing 12 people, 1000s of fish & toxicating river. It was country's worst environmental disaster
What are pros and cons of protection?
PROS: Simple blanket ban easier to enforce, no grey line over what is too much CONS: no money can be made from natural resources (may halt country's development); can appear artificial to tourists; poachers may still break rules & hunt illegally
What are pros and cons of conservation?
PROS: Supported by NGOs; Money still made from natural resources; Still access to resources for locals & gov.s; Good balance between no access & over-exhausting resources CONS: Difficult to draw line and find balance between what is/ isn't allowed; gov.s still open to corruption; it'd take lots of cooperation & negotiation to cut back, cutting out completely would be simpler and easier
How do plants survive the rainforests' heavy rain, heat & humidity?
RAIN: -Waxy leaves & tips allow water to run off -Passing water to soil or returning it to atmosphere -Having leaves that cope with large amounts of water falling on them HEAT & HUMIDITY: -Using circulating water as cooling system
What is slash & burn? Why is it better than deforestation?
Small areas are cleared in this type of subsistence farming, then once soil gets exhausted, the indigenous tribes move on, allowing the soil to regenerate. However in deforestation soil erosion and degradation means soil cannot regenerate.
What are the main challenges of deforestation in the tropical rainforest?
The scale, speed and wasteful use of tropical rainforest's land and resources from the causes of deforestation are what make all the challenges.
How are indigenous tribes impacted by deforestation?
They decline, e.g. now only 240 tribes left, compared to over 330 in 1900. People are forced out by road construction, logging, mine openings, creating ranches, plantations and reservoirs. Displaced people end up in towns/cities and struggle to adjust, often getting addicted to drugs/alcohol and dying young. Knowledge of forest & medicinal values of species is lost with the tribes. But around 1 million indigenous people still live in Brazil, through subsistence farming/ hunter-gathering/ low-impact farming of forest products, & are less easily forced out, knowing their rights.
What does sustainable management mean?
Using goods & services in a way that they're still available for benefit of people in the future.
How does the excellent nutrient cycling contribute to biodiversity in the tropical rainforest?
Variety of vegetation thrives despite poor soils, as excellent nutrient cycling means nutrients for plants & then animals can inhabit the area too.
How is local climate change impacted by deforestation?
Water cycle gets disrupted as tree felling reduces evapotranspiration, so moisture returning to atmosphere reduced & drier local climate. Water cycling also a cooling system, so reduced cycling means warmer local climate. Increasing dryness & rising temps is bad for people and activities, e.g. agriculture.
What is protection?
Where environment should be left untouched & humans should not interfere, so ecosystems can find their balance.
What is conservation?
Where natural resources, e.g. timber, can still be used, but it must be sustainable.
Why do we need to protect & conserve the rainforest?
Without protection, goods and services could be lost forever, and forest's stock of renewable resources will gradually get exhausted. Large-scale deforestation has no place in sustainable management.
