TROPICAL RAINFORESTS

• what are the trees like in the tropical rainforest?

  • Very tall and have layers
  • emergent are up to 50m
  • canopy blocks out most of sunlight and contains most wildlife
  • the under canopy contains tree trunks and lianas
  • the shrub layer has little sunlight and dense shrubs which don't require as much light through
  • forest floor is damp and dark which contains dead animals and litter which decomposes very quickly
• why is the soil lackign nutrients?

  • leached due to the heavy rainfall
  • rapidly absorbed by vegitation
• how is vegetation adapted for the rainforest?

  • Large leaves to absorb as much light as possible for photosynthesis
  • wide buttress roots absorb all the nutrients in the top layer of soil
  • Thick waxy cuticle and drip tips to avoid the leaves being damaged by the heavy rain
  • epiphytes grow on other plants and can get their moisture and nutrients from the air
  • leanas use taller plants to help them climb to reach more sunlight
• how are animals adapted to the rainforest

  • Poison dart frog is brightly coloured in order to warn predators against eating it
  • sloths are inactive during the day to avoid predators. Their arms are longer than their legs and their feet are curved so they can easily grasp branches. They are camoflage and move very slowly to avoid being seen by predators. They have sharp teeth to defend themselves from predators
  • Spider monkeys have long tails which allow them to grasp trees so they can swing and pick fruit with it
• how biodiverse is a rainforest

  over 170,000 plant species
• why does a TR have so much biodiversity?

  • Stable climate - high rain and warm temps allows plants and animals to thrive and supports plant growth all year round
  • Layered structure creates many habitats for different species
  • nutrients are rapidly recycled which can speed up plant growth and provides producers with food
  • Large areas which are untouched by humans allows nature to thrive
• what things threaten biodiversity in the TR?

  • Deforestation - leads to habitat and loss of species, disrupts ecosystems
  • Water pollution from agriculture run off and mining which contaminates rivers and harms aquatic life and the baalnce of the ecosystem
  • climate change - rising temps and changing rainfall patterns can alter habitat and disrupt food sources and leads to unwanted migration of species which can destroy ecosystems and food sources
• what are the impacts of lower biodiversity?

  • Undiscovered plants and animals may become extingt
  • Over 25% of medicines origionate from the rainforest, meaning future medical development may be limeted
  • indigeounous people will struggle to survive
• what is the current global rate of deforestation

  1 hectare a second

  31 million hectares a year
• what are the causes of deforestation in the amazon?

  • subsistence and commercial farming
  • logging
  • road buildin g
  • mineral extraction
  • energy development
  • settlement
  • population growth
• how does susbsistance and commercial farming cause deforestation

  • Cattle overgraze
  • Farmers over use their land
  • nutrients in the soil are quickly used up and the soil becomes infertile and will grow nothing
  • this causes the farmers to go and chop down more trees for more land, and they will overuse it again
  • this is a destructive cycle
• how does logging cause deforestation

  • clear felling - all of the trees in one area are chopped down
  • this will lead to soil erosion so the soil isnt able to regrow trees either in the future, so it causes permanent damage
  • Wood such as mahogany and teak are in high demand for furniture and building
  • trees are cut for paper
• how does mineral extraction cause deforestation?

  • Minerals such as gold, copper and bauxite can be found in the soil in the amazon which are in high demand for makign things such as aluminium
  • The development of mines requires large areas of forest to be cleared
• How does building roads cause deforestation?

  • The more economic activity in rainforests increases the needed amount of accessibility, meaning more roads and settlements are needed to be built which requires even more deforestation
• how does energy development cause deforestation?

  • the creation of HEP stations requires areas of forest to be flooded to build dams and resivoires
  • dams and resivoires may also lead to the corrosion of machinery in the water, making it more acidic causing trees and plants to rot
• How does population growth cause deforestation?

  • land is cleared in order to build houses and infrastructure
• what are the effects of deforestation?

  • Climate change
  • Economic development
  • Soil erosion
  • Global - climate change + loss of biodiveristy
  • Local - soil erosion, conflict, economic gain, declien of indigeounous tribes
• how is climate change caused by deforestation

  • The amazon rainforest absorbs large levels of the earth's CO2
  • More CO2 in the air as less trees are absorbing
  • Trees release CO2 when they are burnt
  • Leads to the enhanced greenhouse effect
• How is the water and nutrient cycle impacted by deforestation?

  • Water - trees are felled meaning there is less transpiration meaning there are drier conditions and the climate becomes warmer, meaning things such as agriculture will be less possible
  • Nutrient - less trees means less leaf litter, meaning the soil will become more infertile
• how is soil erosion caused by deforestation

  • Less trees to anchor down the soil - less interception
  • the soil is more exposed to heavy rainfall, meaning more leaching and removal of top soil will occur
  • less vegitation will be able to grow as the nutrients are removed
  • flooding occurs as more soil is washed into rivers
• how are the indigeounous people affected by deforestation?

  • only 240 tribes left in amazon
  • they are forced out of the forest due to road contruction, logging, creation of resivoires, and mines
• how many tribes are left in the amazon rainforest

  240
• how is conflict created as a result of deforestation

  • conflict over land rights and conservation
  • some seek to protect and some seek to exploit the recources for economic gains
  • loggers vs indigenous people
• what goods are supplied by the tropical rainforest?

  • Building materials ie timber
  • Minerals and metals
  • Food crops
  • Energy from HEP
  • Medicine
  • Water
• What services are from the tropical rainforest?

  • Water and nutrient cycling
  • Air purification
  • Biodiveristy
  • Habitats
  • employment opportunities for an improved well being
  • protection against soil erosion and flooding
• what is the value of the tropical rainforest for people?

  Resources

  • Wood
  • Fruit and nuts
  • Minerals

  Medicine

  • 25% of all medicines

  Energy

  • HEP allows and helps LICS and NEES to grow and develop

  Employment

  • many opportunities - tour guide, mining, logging, farming etc
• What is the value of the tropical rainforest to the environment

  Water

  • freshwater source
  • 20% of worlds fresh water comes from amazon basin

  Biodiversity

  • over 50% of earths plants and animals

  Soil erosion

  Climate change
• how can the rainforest be managed more sustainably?

  • selective logging
  • conservation and education
  • ecotourism
  • international agreements about the use of woods
  • debt reduction
• selective logging

  • only the older and inferior trees are cut down
  • causes less damage as remainign trees provide soil cover, meaning there is less soil erosion and nutrients is left in the soil
  • young trees have a guarenteed life span and are able to grow to their full potential before being chopped down
  • ensures it can be used by future gens
• conservation and education

  • those involved in exploitation understand the consequences of their actions
  • educate the rest of the world so they also understand the impact
• ecotourism

  • dosent damage the enviornment and respects local culture - cabins are made of local wood
  • employs local people
  • small groups travel to areas to learn about animals and biodiversity in the rainforest - this can help spread the message as to why it is important to protect it
• international agreements on the use of hardwoods

  • wood such as mahogany is in high demand in HICs for furniture, leading to illegal deforestation
  • International agreements restricts the sale and export of illegal wood which is not from a sustainable source
  • sustainable and legal wood is marked with a logo so buyers know
• debt reduction

  • many LICs which are heavily in debt can make agreements with HICs where they agree to use money to conserve the rainforest, rather than pay back a debt