Olea europaea L. in the North Mediterranean Basin during the Pleniglacial and the Early–Middle Holocene

Abstract

The paper aims to define the natural distribution of Olea europaea L. var. sylvestris (Miller) Lehr. in the North Mediterranean basin during the Pleniglacial and the Early–Middle Holocene by means of the identification of its wood-charcoal and/or wood at prehistoric sites. For this purpose we have reviewed the previously available information and we have combined it with new wood-charcoal analyses data. We have taken under consideration the presence and frequency of O. europaea L. in the available wood-charcoal sequences, the characteristics of the accompanying flora, the associated chrono-cultural contexts, the broader biogeographical context and the AMS dates provided by Olea wood-charcoal or endocarps. According to the available evidence, during the Middle and Late Pleniglacial (ca 59–11.5 ka cal. BP), Olea would have persisted in thermophilous refugia located in the southern areas of the North Mediterranean basin, the southern Levant and the north of Africa. The Last Glacial Maximum (ca 22–18 ka cal. BP) probably reduced the distribution area of Olea. During the Preboreal and the Boreal (ca 11 500–8800 cal. BP) the species started to expand in the thermomediterranean bioclimatic level. In the western Mediterranean, during the Atlantic period (ca 8800–5600 cal. BP), the species became very abundant or dominant in the thermophilous plant formations and expanded to favorable enclaves outside the limits of the thermomediterranean level.