Ecosystem Stability: Skills (HL IB Biology)

• The Amazon rainforest is an example of an ecosystem where human activities are endangering ecosystem sustainability
• Deforestation is affecting the self sufficiency of the Amazon ecosystem by influencing its temperature and rainfall
  • Transpiration releases water vapour into the air above the rainforest
  • This has a cooling effect which affects air movement and rainfall
  • Changes in the number of trees carrying out transpiration can therefore influence local temperatures and rainfall
• Temperature and rainfall are factors in the rates of photosynthesis and nutrient cycling, so deforestation could have a knock-on effect on other important ecosystem stability factors
• Scientists are concerned that the Amazon could reach a tipping point beyond which it is no longer stable
  • So many trees are removed that temperature and rainfall patterns change significantly
  • Climatic factors may change beyond tolerance levels for some species
• There is uncertainty around the area of rainforest that would need to be lost for this tipping point to be reached, so we do not know how close the Amazon rainforest is to losing stability

Global deforestation map

Information from 2015 shows high rates of annual deforestation occurring in the Amazon rainforest, South America; it is thought that this deforestation could destabilise the ecosystem if it is allowed to continue