Vegetation changes during the late Pleistocene and Holocene in Lebanon: a pollen record from the Bekaa Valley

Abstract

A sediment core retrieved from Quaternary deposits from the Aammiq wetland (Bekaa Valley, Lebanon) provided a pollen record carrying valuable information which allowed reconstruction of past vegetation dynamics in relation to climate change and anthropogenic impacts. Core stratigraphy and microfossil data helped interpret the depositional settings of the sequence. Before c. 12.2 kyr cal. BP, an expansion of cedars ( Cedrus libani) and deciduous oaks ( Quercus cerris-type) is observed. The Younger Dryas is marked by the spread of a Chenopodiaceae steppe and a regression of cedars and deciduous oaks. During the early Holocene, an open oak forest expanded concomitantly with the development of a marsh in the Bekaa Valley. Between c. 6.0 and c. 3.4 kyr cal. BP, major disturbances in the sedimentation process are recorded, leading to some dissimilarities with other palaeobotanical records from the Eastern Mediterranean region. After c. 3.4 kyr cal. BP, the pollen data reveal that agriculture in the Bekaa Valley was mainly oriented towards livestock rearing since there is very little record of cultivated plants. In this regard, the results conflict somewhat with other studies carried out in the Eastern Mediterranean region, where intensive cultures have been observed since the early Holocene. Cultures might have been present in other regions in Lebanon but apparently not in this part of the Bekaa Valley.