EGU21-7425
https://doi.org/10.5194/egusphere-egu21-7425
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Continental-scale modelling of the effects of climatic and non-climatic disturbances on woody plant encroachment in the grasslands of Africa

Francesco D'Adamo1, Rebecca Spake1,2, James Bullock3, Booker Ogutu1, Jadunandan Dash1, and Felix Eigenbrod1
Francesco D'Adamo et al.
  • 1School of Geography and Environmental Sciences, University of Southampton, Southampton SO17 1BJ, UK
  • 2Land Use and Ecosystem Services Research Group (LUES), Forest Research, Farnham GU10 4LH, UK
  • 3UK Centre for Ecology & Hydrology, Wallingford OX10 8BB, UK

Grasslands cover ca. 7% (2,100,000 km2) of the African continent. They provide a wide range of ecosystem services (e.g., forage, water, recreational spaces, carbon sequestration), and host large wildlife communities. Despite their importance, African grasslands are reported to be suffering from degradation and, perhaps more worryingly, have received little consideration within international policies (e.g., United Nations Sustainable Development Goals). A key issue at present is widespread woody plant encroachment (WPE), which it is shifting African grassland from a grassy- to a (less palatable) woody-dominated biome. However, the way climatic (e.g., precipitation, soil moisture) and non-climatic disturbances (e.g., fire, population density) affect WPE is still poorly understood, particularly at large spatiotemporal scales. Here we identified grasslands in sub-Saharan Africa according to the ESA Climate Change Initiative (CCI) land cover product and use vegetation optical depth (VOD) from passive microwave observations as a proxy for woody vegetation change between 1992 and 2011. We then use independent climatic (precipitation and soil moisture) and non-climatic (burn intensity, population change) data to assess how both spatiotemporal variations and interactions between climatic and non-climatic drivers controlled rates of VOD increase during 1992-2011. We consider not only annual precipitation, soil moisture, fire, and population data, but also integrated and lagged precipitation data (both up to five years ahead of VOD) in these models. Preliminary results reveal a large overall increase in woody vegetation in sub-Saharan Africa grasslands as well as considerable spatiotemporal variation in VOD change that is not due to climatic factors alone.

How to cite: D'Adamo, F., Spake, R., Bullock, J., Ogutu, B., Dash, J., and Eigenbrod, F.: Continental-scale modelling of the effects of climatic and non-climatic disturbances on woody plant encroachment in the grasslands of Africa, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7425, https://doi.org/10.5194/egusphere-egu21-7425, 2021.