Ecosystem responses in Africa under different CO 2 fertilisation futures

Climate model results and emission scenarios have been used in simulations to project ecosystem changes in Africa in response to warming and changing precipitation patterns. Less explored are plant responses to elevated CO2. The ecosystem model Af-Range was used to address seven hypothesised responses for three climate forecasts and two shared socioeconomic pathways. The application represented Africa and herb, shrub, tree and herbivore dynamics. Remotely sensed surfaces were used to assess simulations. Simulations using the climate forecasts for pathway 3-7.0 and with the nutrient limitation hypothesis showed annual net primary production declining by 32% for the most extreme climate model (i.e. ACCESS-ESM1-5) but small changes under pathway 1-2.6. Tree cover expanded as those C3 plants were favoured by elevated atmospheric CO2, and leaf area indices and total aboveground live biomass increased. Differences in selected outcomes under the elevated CO2 hypotheses were often below 5%, but climate change effects differed greatly across the grasslands, closed and open shrub grasslands, and savanna and wooded savannas summarised. Soil total organic carbon concentration increased in open shrublands across all climate change models, whereas grasslands and savannas showed large changes in primary production, cover estimates and leaf area indices for shared socioeconomic pathway 3-7.0.