Yannick Garcin (University of Postdam) and collaborators, including partners supported by the LabEx OT-Med (Pierre Deschamps and Guillemette Menot), have just published a new explanation for the rainforest crisis in Western Central Africa.
By integrating vegetation, hydrological, and archaeological records, the team resolved the controversy over the amplitude of the early human impact on the rainforest, providing evidence that humans triggered the rainforest fragmentation 2,600 y ago.
Results of this multidisciplinary approach are presented in a recent PNAS publication.
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Significance
Modern human societies live in strongly altered ecosystems. However, anthropogenic environmental disturbances occurred long before the industrial revolution. About 2,600 y ago, a forest–savannah mosaic replaced dense rainforests in Western Central Africa. This rainforest crisis was previously attributed either to the impact of climate change or, to a lesser extent, to the expansion of Bantu peoples through Central Africa. A 10,500-y sedimentary record from Lake Barombi, Southwest Cameroon, demonstrates that the rainforest crisis was not associated with any significant hydrological change. Based on a detailed investigation of a regional archaeological database, we present evidence that humans altered the rainforest ecosystem and left detectable traces in the sediments deposited in Lake Barombi.