Vegetation response to millennial- and orbital-scale climate changes in Africa: A view from the Ocean

Abstract

Pollen from deep-sea sedimentary archives have proved to be a particularly useful tool to provide an integrated regional reconstruction of vegetation and climate (temperature, precipitation, and seasonality) on the adjacent continent throughout the Earth’s climate history. In this paper, we have compiled marine pollen records from the African margin in order to assess long-term patterns of vegetation changes during climate cycles. We investigate the changing and complex interplay between African climate and high- and low-latitude forcing at orbital and millennial timescales. More importantly, the study of those records has shown the extent of different biomes during the last ten million years covering the Plio-Miocene, glacial-interglacial cycles, as well as eight Heinrich Stadials, the last deglaciation and the Holocene. In the West African records, arboreal pollen expanded during most interglacials and during the early Holocene. The 350savannah and semi-desert/desert vegetation expanded abruptly during glacials, Heinrich Stadials and the Last Glacial Maximum. Most eastern African pollen records have shown a clear dominance of arboreal taxa throughout all climate cycles except during MIS32 suggesting that a decoupling between eastern and western Africa took place. However, the scarcity of eastern African marine pollen records hampers a reliable comparison between these two sectors.