A 20,000-year sediment core contains pollen showing forest-to-farmland transition 5,000 years ago. The sudden increase in grass pollen and charcoal marks the exact moment agriculture transformed the landscape.
Theugursevinc, CC BY-SA 4.0, via Wikimedia Commons
A library of ancient pollen
Lake Beyşehir, the largest freshwater lake in Turkey, holds a detailed environmental history in its floor sediments. By drilling long tubes deep into the lakebed, scientists extract sediment cores that are timelines, with the deepest layers being the oldest. These columns of mud contain microscopic pollen grains, charcoal fragments, and other biological material that settled in the lake year after year for millennia. This practice, known as palynology, allows for a reconstruction of the region's vegetation and climate stretching back thousands of years.
The pollen record from Beyşehir Lake shows the landscape before widespread human settlement. In layers dated to the early Holocene, around 9,000 years ago, arboreal (tree) pollen accounts for about 25% of the total. The dominant tree species identified through their pollen are Pinus (pine), Cedrus (cedar), and Quercus (oak). The other 75% of the pollen comes from non-arboreal plants, primarily steppe species like Artemisia and members of the Chenopodiaceae family, indicating a landscape of semi-open forest and steppe.
The agricultural signal
A distinct shift appears in the sediment layers corresponding to a period between roughly 3,500 and 1,300 years ago. Researchers have named this event the "Beyşehir Occupation Phase" (BOP). During this interval, the amount of tree pollen decreases sharply. Simultaneously, there is a dramatic rise in pollen from the grass family (Poaceae), including cultivated cereals. Pollen from plants associated with cultivation and disturbed ground, such as Plantago (plantain), Juglans (walnut), and Castanea (chestnut), also becomes common.
This change in the pollen assemblage is accompanied by a significant increase in microscopic charcoal particles. The charcoal shows fire being used on a large scale to clear forests for agriculture and grazing land. The combination of forest clearance, the cultivation of cereals and trees like olive and walnut, and evidence of pastoralism defines this transformative period in the landscape's history. This distinct signature in the lake's mud is a precise environmental marker for the intensification of human land use in ancient Anatolia. After this phase, around 1,300 years ago, many pollen records show an increase in tree pollen again, suggesting a period of reforestation or "rewilding" as settlement patterns changed.
💡Fun Facts
Lake Beyşehir is a tectonic lake, formed by movements in the Earth's crust, and contains 33 islands of various sizes.
The sediment cores track human activity but also major climate shifts, such as the cold, dry Younger Dryas period around 12,000 years ago.
The pollen record identified specific cultivated trees, including walnut (*Juglans*), sweet chestnut (*Castanea*), and olive (*Olea*), as part of the agricultural landscape.
The lake and its surroundings are now part of the Lake Beyşehir National Park, which hosts over 150 bird species and 88 endemic plant species.
Lake Beyşehir National Park is a natural, public area and is always accessible. The sediment cores themselves are part of scientific collections and are not on public display.
Admission
Free
Accessibility
The areas around the lake include public beaches, promenades, and parkland, much of which is flat and easily accessible. Surrounding terrain can be mountainous.
