Modeling past and future climate induced vegetation changes in East African savannas
Istem Fer, Alexis Synodinos, Britta Tietjen, Florian Jeltsch
We investigate the complex dynamics of East African vegetation from two different perspective:
On the one hand we attempt a spatially extensive reconstruction of the various biomes of East Africa with a mechanistic, dynamic vegetation model. The first step in this approach is to validate the model for the region by comparing its outputs to present-day observational vegetation data (i.e. vegetation maps, modern pollen data). After establishing that the model can successfully simulate the modern vegetation distribution of the region, we proceed to reconstructing the paleo-vegetation and compare the outputs with fossil pollen data. Finally, we compare both periods' vegetation distributions and explain the environmental variables that might be responsible for the differences we observe.
For the other approach we designed a model of savanna dynamics using Ordinary Differential Equations. First, we attempt to understand the mechanisms that allow for the long term persistence of the savanna biome. Contrary to the current consensus we argue for the importance of grass facilitation in preserving arid and semi-arid savannas. We aim to investigate the resilience of this biome to climatic and environmental changes and understand how grass facilitation may function as a buffering mechanism against ecosystem degradation. Finally, we will look to explain past biome shifts in East Africa in response to major climatic events.