Expected Impacts of Climate
Change on Biome Stability in
the Namakwa District:
new biome envelope predictions & identification of
areas supporting resilience
Dr Stephen Holness & Prof Guy Midgley
Springbok
Dr Stephen Holness
sholness@nmmu.ac.za
March 2012
Components
• “Areas of biome stability”
– Particular parts of the Namakwa District are at
higher risk from climate change induced impacts
• “Areas important for supporting ecosystem
resilience to climate change impacts”
– Intact ecosystems have the potential to reduce
climate change impacts through supporting
ecosystem based adaptation
– Particular parts of the district are of particularly
high value for supporting cc resilience
Technical process (1)
• Revised climate data from 15 GCMs were used to
calculate anomalies between now and mid century
• Does not focus on a single model
• Used the range of predicted outcomes from these
models to define three scenarios:
– High risk scenarios with low rainfall and high
temperatures
– a medium risk scenario
– and low risk scenario with high rainfall and smallest
temperature
• Anomaly calculated and combined with current
agro hydrology data
Technical Process (2)
• MAXENT - widely used ecological modelling
and forecasting program (we will now extend
this to other methods)
• Model of current biomes & test prediction ability
• Develop biome maps for future high, medium
and low risk scenarios
• Identify areas with high risk of biome envelope
change and areas which are likely to remain
stable.
Can we predict biomes?
“Actual current”
“Modelled current”
•MAXENT models of each biome
•Biome determined by strongest model outputs at each site
•86% accurate prediction – most missed blocks have a mixture or are on boundaries
Changes
Current Biomes
Current Biomes
Low risk scenario
Medium Risk Scenario
High risk scenario
Consistently predicted areas in all scenarios
Areas of biome stability
But...need to use new data