Late Holocene vegetation dynamics and climate variations through pollen analysis of sediments from Lake Sülük (Çorum, Türkiye)

The sediment core from Lake Sülük provides evidence of significant vegetation and environmental changes during the late Holocene, covering the last 2170 yr BP. The period of 2170–1650 yr BP revealed the dominance of Pinus and Asteraceae-Cichorioideae, indicating cooler, drier conditions with open pine forests and herbaceous understories, particularly during the Hellenistic-Galatian and early Roman periods. During the same period, an increase in the Pollen Disturbance Index (PDI) indicates long-term local grazing or breeding activities. The pronounced increase in Pinus pollen between 1300 and 1150 yr BP suggested the expansion of pine forests, which was likely influenced by favorable climatic conditions or changes in land use. The rising levels of Artemisia and Poaceae indicate mixed pastoral and agricultural activities. Pinus dominance peaked during the Seljuk Empire. In the late Antiquity Period, other woody species, such as Alnus, Carpinus betulus, and deciduous Quercus, expanded locally, while the rise of Ranunculus species highlights their resilience to arid Mediterranean conditions. After 610 yr BP, the abundance of Pinus declined, allowing other arboreal species, particularly deciduous Quercus and Juglans, to thrive notably during the Ottoman Empire. The presence of cultivated trees, including Juglans, Vitis, and Olea europaea, confirms extensive agricultural activities during the Ottoman period, reflecting human influence on the vegetation. Mixed deciduous and coniferous forests dominated the surrounding mountains, whereas riparian zones were characterized by Populus and Salix. The interaction between natural ecosystems and human settlements is evident, with vegetation shifts driven by both climatic changes and human activities.