The vegetation history of Lake Mert and its surroundings for the last 6600 years (Kırklareli, NW Türkiye)

The primary aim of this study is to determine the Middle-Late Holocene vegetation history of the İğneada Longoz (Floodplain) Forests around Lake Mert, located in Kırklareli, using high-resolution palynological analysis conducted on the MRT-04 core. Pollen analyses was performed on sediment samples collected from 67 different levels within the core. Pollen counting and identification were performed using a Leica DM750 light microscope, with a minimum of 500 terrestrial pollen grains counted per sample. The age of the lake was determined to be 6600 years old through radiocarbon dating of the core. According to the findings from the pollen analysis, deciduous mixed oak forests have dominated the region in and around Lake Mert for the past 6600 years. Within these mixed oak forests, Quercus cerris type (deciduous oaks) is predominant, with notable contributions from Fagus, Carpinus, Corylus, and Tilia. This forest composition has displayed a consistent pattern, except for changes attributed to the expansion of temperate species and human influences. The distribution of mixed oak forests began to decline around 1360 BP, coinciding with a significant increase in the presence of Alnus, Fraxinus, and Ulmus. These trees are characteristic species of floodplain forest and indicate the initiation of the formation of the İğneada Longoz Forests after 1360 BP. Furthermore, around 420 BP, there was a substantial decrease in the pollen percentages of Quercus and Fagus. During this period of declining mixed oak forests, Plantago and Ambrosia appeared for the first time in the pollen diagram. The reduction in arboreal plant taxa and the rise of herbaceous taxa such as Plantago, Ambrosia, and Poaceae, which serve as indicators of human impact, signify the conversion of forested areas into agricultural and pasture lands.