Ecosystem management can mitigate vegetation shifts induced by climate change in West Africa

The welfare of people in the tropics and sub-tropics strongly depends on goods and services that savanna ecosystems supply, such as food and livestock production, fuel wood, and climate regulation. Flows of these services are strongly influenced by climate, land use and their interactions. Savannas cover c. 20% of the Earth's land surface and changes in the structure and dynamics of savanna vegetation may strongly influence local people's living conditions, as well as the climate system and global biogeochemical cycles. In this study, we use a dynamic vegetation model, the aDGVM, to explore interactive effects of climate and land use on the vegetation structure and distribution of West African savannas under current and anticipated future environmental conditions. We parameterized the model for West African savannas and extended it by including sub-models to simulate fire management, grazing, and wood cutting. The model projects that under future climate without human land use impacts, large savanna areas would shift toward more wood dominated vegetation due to CO2 fertilization effects, increased water use efficiency and decreased fire activity. However, land use activities could maintain desired vegetation states that ensure fluxes of important ecosystem services, even under anticipated future conditions. Ecosystem management can mitigate climate change impacts on vegetation and delay or avoid undesired vegetation shifts. The results highlight the effects of land use on the future distribution and dynamics of savannas. The identification of management strategies is essential to maintain important ecosystem services under future conditions in savannas worldwide.