ABSTRACT

The Niger Delta is located in a region of great sensitivity to climate change, offering the potential to provide an insight into environmental change during the Late Quaternary in Equatorial Africa. This deltaic environment and dynamically linked vegetation system had been sparsely studied if compared with other major tropical deltas and its response to past climate change and vegetation development is therefore poorly understood. This study provides a chronological interpretation of palynomorph data from three gravity cores that has enabled the differentiation of warm and dry climate intervals, and the factors controlling vegetation change (Intertropical Convergence Zone and West African Monsoon). An array of palynological sequences defined in the three gravity cores show very similar fluctuations, with a dominance of Afromontane Forest (Podocarpaceae), Freshwater Swamp (Cyperaceae), Savannah (Poaceae), and Lowland Rainforest (Polypodiaceae) elements during the late glacial (MIS2) and deglaciation (MIS1) periods, followed by the significant establishment of coastal fringing mangroves (Rhizophoraceae) during the Early to Mid-Holocene. In addition, high values of significance charred grass cuticles were observed in samples from the late glacial period, whereas the expansion of mangrove vegetation is concomitant with the relatively warmer interglacial period. These records suggest dry conditions during the late glacial and deglaciation periods, and warmer conditions during the subsequent interglacial period of the Early to Mid-Holocene periods, respectively. The data presented here demonstrate a close relationship between prevailing climate change and the control on vegetation evolution in the Niger Delta when compared with previous studies from Equatorial West Africa.