tropical rainforests Flashcards
what are tropical rainforests and where are they found
trfs are dark, damp and dense ecosystems
they are found between the tropics
what is climate like
• warm: overhead sun means temperatures average 27° throughout the hear
• wet: over 2000mm annually. Hadley cells causes warm air to rise at equator, which cools and condenses and triggers heavy rain
rainfall varies - directly overhead equatorial low pressure caused wet season
what is soil like
- despite lush vegetation, soil is very infertile. this is because the heavy rain makes trfs prone to leaching, where nutrients are washed away
- high temperatures means dead matter decomposes rapidly meaning there is a layer of nutrients on the surface. plants have shallow roots to absorb these nutrients
how does nutrient cycling work
- plants are producers, meaning they take in nutrients from the soil for growth. consumers (animals) eat these plants for energy
- when these consumers and producers die or shed leaves, decomposers break down the organic matter into nutrients. due to the high temperatures, this decomposition occurs rapidly
- this causes nutrients to sink into topsoil, and are then absorbed by plants. due to high rainfall, the other nutrients are be quickly washed away. this is known as leaching, and it means that nutrients do not sink very far into the soil. because of this, plants have adapted to have very shallow roots
- these plants decay and die, and cycle starts again.
why is there high biodiversity in trfs
high rainfall and temps = ideal plant growth. the lack of seasons also means plants grow all year round.
more plants = more herbivores = more carnivores
what are emergents
trees that grow extremely fast to out-compete other trees to be more exposed to sunlight for photosynthesis
what are buttress roots
massive ridges called buttress roots that stabilise larger trees
they are above ground to avoid the nutrient deprived soils deeper deeper down.
they also increase surface area, which helps with gas exchange
how are plants adapted to avoid waterlogging
smooth bark: water runs off quickly when rainfall is high
leaves: have “drip tips”, shaped to allow water to drip off
how are sloths adapted to trfs
they spend 99% of time in trees so:
- naturally long and curved claws to hang from branches
- reversed musculature to hang upside down from branches
- direction of fur allows rainfall to drip off it
hat is deforestation
cutting down of trees, often on a large scale
why are forests important to malaysia
67% of malaysia is trfs
rates of deforestation in malaysia
equivalent if a football pitched cleared every 4 mins
lost 16% primary trf from 2002 - 2018
what are the causes of deforestation
population growth
commercial farming
substistence farming
mineral extraction
energy development
how does population pressure lead to deforestation in malaysia
- poor people encouraged to migrate urban to rural
- large areas need to be cleared for settlers, e.g 15000 ha cleared between 1956 and 1980s
- many of which set up plantation, more cleared, often unsustainably due to lack of education in land clearing
how does commercial farming lead to deforestation in malaysia
malaysia is largest exporter of palm oil
- huge areas cleared for plantations
- plantation owners receive 10 year tax incentives, encourages conversion to plantation
how does subsistence farming lead to deforestation in malaysia
- small scale farmers and tribal communities gather only their own food from forest
- slash and burn: trees cut down. dried out shrubs left behind is burned, ash releases nutrients to soil to allow more cultivation. however risk of wildfire
how does logging lead to deforestation in malaysia
1980, malaysia was largest tropical wood exporter.
- clear felling used: all trees chopped in an area
- required road construction and heavy machinery
- recently replace with selective logging: chopping mature trees only
how does energy development lead to deforestation in malaysia
- dams constructed for hep e.g bakun
- large areas need to be flooded for reservoirs. destroys indigenous communities and habitats
bakun: 700km^2 flooded
impacts of deforestation / value of trfs
- biodiversity and ecosystems
- exposes soil (soil erosion)
- carbon sink destroyed
- 50 million indigenous people live in trfs for food water and shelter
- provides valuable wood as well as nuts, fruits, rubber
- trf plants supple 25% all medicine, 2000 have anti - cancer properties
economic gains of deforestation
- job creation (mining, farming, supply)
- companies pay tax to government, money spent to improve services
- valuable minerals exported (gold, tin)
economic losses of deforestation
- decrease in trf tourism
- medically beneficial plants extinct
- rising temperatures means certain crops (fruit, tea) unable to grow
ways to sustainably manage trfs
- selective logging and replanting
- ecotourism
- international agreements
- conservation and education
how does selective logging and replanting sustainably manage trfs
selective logging - only mature trees cut, limits disturbance and allows growth of younger trees
replanting - increases sustainability of logging, mitigates soil erosion
how does conservation and education sustainably manage trfs
• conservation - national parks and nature reserves encourage preservation of trfs, creates tourism
• education - educating customers and companies of the environmental impacts from their products:
- reduces demand of said products
- encourage conversion to sustainable versions
