07/11/16 Seminaire Européen. Yannick Garcin (University of Potsdam)
Impacts of hydrological changes versus human activity on the Central-West African forests during the Holocene
Central-West Africa hosts the second largest contiguous expanse of moist tropical forest in the world, which is currently under severe threat of humans through deforestation and forest fires. To understand the underlying processes controlling changes within tropical forests of Africa, it is important to determine the drivers responsible for the past forest disturbances. During the Holocene those tropical forests underwent alternating periods of expansion and contraction, driven by climate variability, although during the last ~3000 years human activity may have had an additional effect. However, the existence of marked episodes of human disturbances in the past remains equivocal. To resolve the drivers and mechanisms, which have affected the Central-West African forests during the Holocene, we propose to analyse novel climate-proxies directly recording changes in the hydrological cycle in combination with vegetation-proxies and indicators of anthropogenic disturbances. We will use a new sediment core collected in Lake Barombi Mbo (Southwest Cameroon) and we will apply molecular-based proxies: compound-specific hydrogen and carbon isotope ratios. These sedimentary molecular and isotopic data will be compared with pollen and other sedimentological data (including erosion proxies) from the same core and also with regional archaeological information and syntheses. This integrated dataset should provide a robust paleo-environmental framework to test the role of climate change and human activity on the evolution of forests in Central-West Africa during the Holocene.
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