Holocene vegetation of the Central Saharan Mountains: the end of a myth

Abstract

Since the end of the 1950s it has generally been accepted that, during the mid-Holocene humid period, the central Saharan mountain vegetation (Ahaggar, Tassili-n-Ajjer and Tibesti) was clearly Mediterranean or even forest in nature. In addition to the present-day elements growing in North Africa the flora was supposed to have included some European arboreal species. This concept was mainly based on the results of pollen analysis. More recent pollen and macrofossil analysis of organic sediments from the Ahaggar massif show that mid-Holocene flora was actually very similar to that found at the present day. Earlier studies had included analysis of sediment contaminated by pollen transported long distances which had accumulated over a period of 4000 years. An endemic olive (Olea laperrini) and the Atlas pistachio tree (Pistacia atlantica), two species which are still well represented nowadays, dominated the vegetation. The new data question the extension of the Mediterranean vegetation towards the south and the amplitude of the associated climatic change.