Changing Ecosystems (AQA A Level Geography)
Revision Note
Written by: Jacque Cartwright
Reviewed by: Bridgette Barrett
Climate Change & Ecosystems
On a global scale, changes to the climate - especially rapid change - has the potential to cause ecological collapse, especially when species cannot adapt at the same rate of climate change
The overall effect is one of three ways:
Species die out allowing other species to dominate (either through inward movement or natural order of existing species)
Species respond through adaptation if given time
Species move to other areas with more suitable conditions
Changes include:
Temperature rise - affects the distribution of species, particularly those sensitive to temperatures (coral reef, polar bears etc.) leading to changes in ecosystem composition and species death
The IPCC estimates that a rise of 1.6°C will affect 20-30% of all plant and animal life at risk of extinction
Extreme weather - floods and droughts are expected to increase which could kill species unable to adapt to wetter or drier climates
In the UK, beech woodland is at risk from summer droughts and change in migratory bird paths
Sea level rise - (melting ice and thermal expansion of oceans) puts coastal ecosystems at risk of being permanently lost and saltwater intrusion into freshwater systems endangers species found within or force them to move further inland
Salt marshes along the coast of the UK are at risk of being submerged permanently through rising sea levels, endangering breeding patterns of birds and other animals reliant of this ecosystem
Climate Change Impacts on Europe
Mediterranean Region | Arctic Region | Coastal and Regional Seas | Mountainous Regions | Northern Europe | Central and Eastern Europe | North-western Europe |
|---|---|---|---|---|---|---|
Temp. rise is more than European average | Temp. rise is more than global average | Increase in sea surface temps. | Temp. rise is more than European average | Temp. rise is more than global average | Warm temp. extremes increase | Increase rise in temps above European average |
Decrease in annual precipitation | Decrease in sea ice cover | Increase in winter precipitation | Glacial volume and extent decreases | Snow, lake and river ice decreases | Decrease in summer precipitation | Increase in winter precipitation |
Increased desertification | Decrease in permafrost | Increase ocean acidification | Decrease in mountain permafrost | Increased river flows | Increased rise in water temps. | Increased river and coastal flooding |
Increased water demand | Intensified shipping and exploitation of oil and gas | Expansion of fish and plankton species northwards | Upward shift of plant and animal species | Increase in hydropower potential | Increase risk of forest fires | Decrease in energy demand for heating |
Higher mortality rates and risks of forest fires | Increased loss of biodiversity and Greenland ice sheet | Decreased fish stock | Increase risk of soil erosion and loss of tourism | Increased summer tourism and damage from winter storms | Decrease in economic value of forests | Increased demand for energy for cooling |
Human Exploitation of Ecosystems
Human exploitation of ecosystems has changed them over time
Deforestation has had the biggest impact globally, with over 50% of all mature forests lost to logging
Tropical rainforests are threatened the most with loss of biodiversity through deforestation
Coastal ecosystems have been damaged through pollution, oil spills and waste (raw sewage and plastics in particular)
Other anthropogenic examples include:
Urban planning - building developments separate natural ecosystems and split populations
Leisure and recreation - diving on coral reef systems disturbs feeding and breeding grounds, touching corals kills the polyps
Marine resources - over fishing has depleted fish stocks to the point of collapse; dredging for sand destroys coastal ecosystems and increases risk of coastal erosion and flooding
Resource use - many species die out through clearance of ground for resources as habitats are destroyed, along with feeding and breeding grounds
Flooding and erosion - management strategies can interfere with natural succession or affect down stream/coastal ecosystems by starving them of nutrients that would normally be transported to the area, thereby preventing species from growing there
Examiner Tips and Tricks
The impacts of climate change are ‘possible futures’, and you should include discussion into a range of ‘possible future outcomes’
Practise clear cause-and-effect sequences in your explanation on questions about how different factors affect ecosystems
Last updated:
You've read 0 of your 5 free revision notes this week
Sign up now. It’s free!
Did this page help you?
