forest under threat

• tropical rainforest climate


  equatorial climate (20 degrees north and south equator)

  hot and wet all year (27-30 degrees and 2000-3000mm precipitation)
• biodiversity


  number of different plants and animals in an area
• structure of rainforest


  emergents

  canopy

  understory

  forest floor
• rainforest plants


  emergent trees adapted to grow 50m+

  drip-tip leaves are waxy to shed water, prevent mould

  buttress roots, tall and slender

  epiphytes evolved to get all nutrients from water so roots dangle
• rainforest animals

  chameleons camouflage to avoid predators

  sloths have huge claws to grip onto trees

  monkeys adapted to travel through canopy
• food web


  diagram to show what everything eats in an ecosystem

  very complex in rainforest due to high biodiversity
• direct threats - deforestation


  cash crops, rainforest cleared to grow stuff for profit

  (75% deforestation in Brazil = cattle farming)

  subsistence agriculture, farming to feed yourself

  leaching is a problem and poverty leads to slash and burn farming

  -commercial hardwood logging

  -mining
• indirect threats - climate change


  warmer temperatures mean less rainfall - droughts, animals cant adapt to change

  eg. flying fox bats die due to heatwaves
• protection -CITES


  convention on international trade in endangered species of wild flora and fauna

  35000 species listed

  +181 countries signed up, targeting issue

  -can't manage all 181 countries
• protection - REDD


  reducing emissions from deforestation and degradation, UN scheme which advises on reducing deforestation and promotes sustainable forest management

  + funding attractive to governments

  -deforestation still happening eg. South Asia
• alternative livelihoods


  ecotourism

  agro forestry
• taiga climate


  subarctic climate - cold, dry, long winters (-40 degrees)

  average summer temperature = 16 degrees

  low precipitation (less than 50mm annually)
• taiga biodiversity


  low biodiversity - short growth period
• taiga plants


  conifer trees, evergeen

  • pine needles - leaves specially adapted: needle shaped
  • waxy coating to avoid water loss
  • dark green to absorb light for photosynthesis
  • cone shaped downward facing branches to tip off snow
• taiga animals


  summer - Canadian taiga has over 300 bird species

  winter - Canadian taiga just 30 species stay as migrate South

  animals that stayed adapted eg. thick fur coats, hibernate
• tropical rainforest nutrient cycling

  biomass is biggest, due to growth from soil

  litter smallest
• taiga nutrient cycling


  litter biggest, due to rainfall and fallout

  soil smallest due to leaching and uptake by plants
• taiga food webs


  much simpler due to lower biodiversity
• taiga direct threats


  commercial development - area with valuable resources sold for money, logging removes trees

  deforestation - high in taiga for softwood

  tar sands - Athabasca in Canada, produces toxic waste, 3x carbon dioxide emissions, destroys habitats
• taiga indirect threats


  wildfires - caused by human activities eg campsites, taiga is adapted to forest fires but have become too frequent so saplings burnt before they can replace old ones

  acid rain - when fossil fuels burnt, sulphur reacts with water and oxygen to form acid rain, kills biodiversity
• case study - James Bay HEP

  located near Hudson Bay in Quebec, Canada

  one of largest HEPs, generates 16500 MW electricity

  cost over $120 billion

  11000 km^2 taiga flooded to build
• conserving taiga


  "Wilderness - It's Official!" project to conserve wilderness, people can visit but have to take rubbish home, not damage etc, no motorised transport, idea is people leave no trace

  National Parks - to conserve wildlife, reduce ecosystem damage but risk of human/animal engagement and pressure for government to develop areas for money