Climate change since the last glacial period in Lebanon and the persistence of Mediterranean species R. Cheddadi a, * , C. Khater b a University of Montpellier II, CNRS-UM2-IRD, ISEM, France b Center for Remote Sensing, National Council for Scientific Research e Lebanon, BP 11-8281, Bir Hassan, Beirut, Lebanon article info Article history: Received 19 April 2016 Received in revised form 6 August 2016 Accepted 8 August 2016 Keywords: Quaternary climate Mediterranean Lebanon Refugia Younger Dryas Holocene abstract In this study, we quantified the mean January temperature (Tjan) and both winter (Pw) and summer (Ps) precipitation from three fossil pollen records from Lebanon. Tjan showed a strong correlation with the global temperature changes retrieved in the NGRIP Greenland ice core. The amplitude of ca. 8  C between the Younger Dryas (YD) period and the Holocene is coherent with climate reconstructions from the Eastern Mediterranean. The overall amount of precipitation was also lower during the YD than during the Holocene but the contrast between Pw and Ps was much more reduced (less than 2 times) during the YD than during the Holocene (up to 8 times). Such different seasonal contrast compare to the present day is coherent with some climate proxies from the Levant that tend to indicate the presence of moisture during the last glacial period. In effect, the low Pw during the YD reflects the replacement of the forest ecosystem by a more shrubby or herbaceous vegetation. Concomitantly, the occurrence of an amount of precipitation higher than the current one during the summer season, along with a reduced evaporation, due to lower temperature, may have contributed to some local observed high lake levels in the area. During the last glacial period, Lebanon was not under a typical Mediterranean climate such as the one we know today, i.e. with a strong precipitation and temperature contrast between summer and winter seasons, but rather under a less contrasted climate. Mediterranean species persisted in this area due to the low amplitude of temperature change between the last glacial period and the Holocene as well as to an availability of moisture throughout the year instead of an occurrence mainly during the winter season as is the case today. © 2016 Elsevier Ltd. All rights reserved. 1. Introduction Nowadays, the Mediterranean area is considered as a hotspot of biodiversity (Myers et al., 2000) due to the persistence of many endemic species over geological times (Biltekin et al., 2015; Van der Wiel and Wijmstra, 1987a, 1987b) during which climate has varied with strong amplitude (Tzedakis et al., 2003). This persistence of species in a specific area through highly contrasted climate periods reflects directly the regional persistence of part of its climatic niche through time. The Quaternary recorded major cyclic climate changes at the global scale (Berger, 1978; Hays et al., 1976; Imbrie et al., 1992; Ruddiman et al., 1989). Yet, some species have persisted in areas where the local (or regional) climate was buffered in comparison to the global climate changes. These areas are named refugia (Bennett and Provan, 2008), whether they are in a glacial or an interglacial period. The most recent period when climate was much colder than today along with a decrease of more than 50% of the overall pre- cipitation amount on the Mediterranean borderlands is known as the Last Glacial Maximum (LGM). Peterson et al. (1979) suggested that Eastern Europe was 12  C colder than today during the LGM. Peyron et al. (1998) reconstructed the mean temperature of the coldest month in western Europe and the Mediterranean and showed that the LGM was 30  C ± 10  C colder than the present. This climate reconstruction has been re-evaluated by Jost et al. (2005) who have obtained a cooling that is between 17  C and 26  C. In a more recent study, Wu et al. (2007) reconstructed the January Temperature and obtained a cooling that is about 5  C lower than Jost et al. (2005). The average disagreement between * Corresponding author. Universit e Montpellier, Institut des Sciences de'  Evoluion, 34095 Montpellier, France. E-mail address: rachid.cheddadi@umontpellier.fr (R. Cheddadi). Contents lists available at ScienceDirect Quaternary Science Reviews journal homepage: www.elsevier.com/locate/quascirev http://dx.doi.org/10.1016/j.quascirev.2016.08.010 0277-3791/© 2016 Elsevier Ltd. All rights reserved. Quaternary Science Reviews 150 (2016) 146e157