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Table of Contents

  1. Introduction: AIACC: Climate Change and Conservation Planning
    1. Chapter1: Evidence for climate change
      1. Chapter 2: Global circulation models
        1. Chapter 4: Biodiversity responses to past changes in climate
          1. Chapter 5: Adaptation of biodiversity to climate change
            1. Chapter 6: Approaches to niche-based modelling
              1. Chapter 7: Ecosystem function modelling
                1. Slide 1: Ecosystem function modelling
                2. Slide 2: Aspects and levels of biodiversity
                3. Slide 3 : Dynamic Vegetation Models
                4. Slide 4: DGVMs continued...
                5. Slide 5: A 'reduced form' ecosystem model for savannas under climate change
                6. Slide 6: Basic savanna system model
                7. Slide 7: Water balance modelling
                8. Slide 8: Controls on grass growth at the annual timescale
                9. Slide 9: Linear relation between grass production and rainfall
                10. Slide 10: Slope: Rain Use Efficiency (g/m2/mm)
                11. Slide 11: Intercept: dependent on soil water holding capacity; co-varies with the rain use efficiency
                12. Slide 12: Effect of trees on grass
                13. Slide 13: Maximum tree basal area
                14. Slide 14: What controls the growth rate of trees?
                15. Slide 15: Effect of CO2 on NEP
                16. Slide 16: Effects of temperature on NEP
                17. Slide 17: What controls tree mortality?
                18. Slide 18: Mammal dynamics
                19. Slide 19: Keeping it together!
                20. Slide 20: Test 1: trees, grass and fire
                21. Slide 21: Test 2: + herbivores, carnivores
                22. Slide 22: Test 3: + elephants
                23. Slide 23: The experiment design
                24. Slide 24: Change in production drivers
                25. Slide 25: Change in vegetation structure
                26. Slide 26: Change in herbivores
                27. Slide 27: Preliminary conclusions
                28. Slide 28: Test yourself
                29. Slide 29: Links to other chapters
              2. Chapter 8: Climate change implications for conservation planning
                1. Chapter 9: The economic costs of conservation response options for climate change
                  1. Course Resources
                    1. Practical: Conservation for Climate Change
                      1. Tests to Assess your Understanding
                        1. How to run a GAM model in R

                          Slide 7: Water balance modelling

                          Duration: 00:01:08


                          Water is key to savanna ecosystem modelling, because they are water limited rather than temperature or light limited. Even when they are nutrient limited, the nutrient availability is controlled by when the soil is moist. Here is a very simple way of modelling water balance, using only the information easily available from climate change simulations: monthly rainfall, maximum temperature and minimum temperature. It ends up as an index of the number of days in the year for which plant growth is possible ('G days')

                          Basically, the water balance is the sum for each month of the average daily amount of precipitation, divided by the daily evaporation, multiplied by the number of days in the month. This assumes that the rainfall is greater than the evaporation; if this is not the case, then the rain over evaporation term is given to be 1. The E0, or open water evaporation is calculated using the second equation. We needn't go into the details of this term, but it is worth noting that it incorporates air temperature (the monthly mean, minimum and maximum) as well as the altitude and latitude of the cell being modelled. This equation was developed by Linacre.