Climate of the Past Discussions www.clim-past-discuss.net 1814-9340 1814-9359 5 6 2009 10.5194/cpd-5-2577-2009 http://www.clim-past-discuss.net/5/2577/2009/ http://www.clim-past-discuss.net/5/2577/2009/cpd-5-2577-2009.html http://www.clim-past-discuss.net/5/2577/2009/cpd-5-2577-2009.pdf 2577 2606 2009-12-22 Vegetation response to the African Humid Period termination in central Cameroon (7° N) – new pollen insight from Lake Mbalang A. Vincens vincens@cerege.fr G. Buchet M. Servant ECOFIT Mbalang collaborators Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement, Université Aix-Marseille, CNRS, CDF, IRD, BP 80, 13545 Aix-en-Provence Cedex 04, France IRD, 32 avenue Henri Ravagnat, 93143 Bondy Cedex, France C. Barton, S. Ngos, F. Nguetsop, S. Servant-Vildary, M. Tchotsoua A new pollen sequence from the Lake Mbalang (7°19<i>'</i> N, 13°44<i>'</i> E, 1110 m a.s.l.) located on the eastern Adamawa plateau, in central Cameroon, is presented in this paper to analyze the Holocene African Humid Period (AHP) termination and related vegetation changes at 7° N in tropical Africa, a region where any data are today available. This sequence, spanning the last 7000 cal. yr BP, shows that the vegetation response to this transitional climatic episode was neither abrupt nor really gradual. Forest degradation in this area is initially registered as early as 6100 cal. yr BP and modern savanna was definitely established at 3000 cal. yr BP and stabilized at 2400 cal. yr BP; but a slight forest regeneration episode is observed between 5200 and 4200 cal. yr BP. Moreover, in this area with modern high rainfall, increasing in the length of the dry season during the AHP termination, from 6100 cal. yr BP onward, has primarily controlled vegetation dynamics and above all the disappearance of a forested environment on the Adamawa plateau. Compared to previous studies undertaken in northern tropical and central Africa, this work clearly shows that the response of vegetation to transitional episodes between climatic extremes such as the AHP termination might be different in timing, mode and amplitude according to the regional climate and hydrology of the study sites, but also according to the stability of vegetation before and during these climatic transitions. Achoundong,~G.: Formation et évolution des recr\^us sur savanes, in: Dynamique à long terme des écosystèmes forestiers intertropicaux, edited by: Servant, M. and Servant-Vildary,~S., IRD, UNESCO, MAB, CNRS, Paris, France, 31–41, 2000. 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