5.4C Impacts of drought on ecosystems

• • Drought has significant impacts on ecosystems
  • The resilience of ecosystems varies
  • Drought reduces the amount of water available for plants and animals
• How drought affects forest ecosystems:

  • Drought conditions leads to forest stress 
  • Younger trees die and this reduces the tree cover
  • Transpiration is reduced and this decreases precipitation and humdity
  • This leads more trees to die
  • The forest becomes less resilient
  • Trees become more susceptible to pests and diseases
  • Wildfire is more common as dry vegetation and litter covers the forest floor
• Forest ecosystem:

  • Forests cover approximately 30% of the Earth's surface
  • They provide vital goods and services including:
  • The release of oxygen
  • High levels of biodiversity 
  • Storage of carbon
  • Trees can draw up to 68-680 litres of water a day
  • On a hot day trees transpire between 500 - 1000 litres
• How drought affects wetland ecosystems:

  • The lack of precipitation causes vegetation to die, which reduces:
  • Infiltration
  • Percolation
  • Interception
  • Transpiration which in turn reduces precipitation
  • In Australia the droughts led to acidification of the wetlands soils and water
  • The drying out of wetlands soils may contribute to climate change due to increased rate of decomposition which release carbon dioxide
• Wetland ecosystems:

  • Covering about 6% of the Earth's surface wetlands:
  • They provide protection from flooding
  • Reduce air temperatures 
  • They improve water quality and have high biodiversity (40% of the world's species)
  • Although wetlands rely on occasional droughts to expose sediments and release nutrients too much drought is damaging