Anthropogenic impact on vegetation and environment during the Bronze Age in the area of Lake Durankulak, NE Bulgaria: Pollen, microscopic charcoal, non-pollen palynomorphs and plant macrofossils

A new pollen core, called “Durankulak-3”, comes from the lake of that name, situated at the Black Sea coast of northeastern Bulgaria. The location of the core close to archaeological sites permits the correlation of palynological data, including non-pollen palynomorphs (NPP) (spores of fungi, remains of algae etc., as defined by van Geel, B., 2001. Non-pollen palynomorphs. In: Smol, J.P., Birks, H.J.B., Last, W. M. (Eds.), Tracking environmental changes using lake sediments. Vol. 3: Terrestrial, algal and siliceous indicators. Kluwer Academic Press, Dordrecht, pp. 99–119.), microscopic charcoal, and plant macrofossils with the archaeological data. A detailed reconstruction of the past vegetation reveals the extent of anthropogenic influence in the area. Radiocarbon dates from the basal part of the core show that the palaeoecological record begins at about 4500 BP. This start corresponds to the end of Chalcolithic and transition to the Bronze Age in the area and is connected with a rise of the lake level around Great Island and the lake shore to the west.Peaks of microscopic charcoal in the lowest part of the core coincide well with those of anthropogenic indicators in the pollen diagram and with the NPP, indicating fire and erosion. These signals can be attributed to the Early Bronze Age activities of nomadic tribes in the area, according to the archaeological record. A second peak of the anthropogenic indicators, well correlated with a peak in the NPP-dung indicators, is probably connected with the Late Bonze Age and Early Iron Age occupation of the area. This suggestion is supported by peaks of Vitis-pollen and the first appearance of Juglans-pollen. In the last zone the vegetation is more and more similar to that of the modern reduced forests and expanded steppe vegetation. In this part of the diagram more specialized crop weeds like Agrostemma githago and Centaurea cyanus appear, most probably originating from rye cultivated there during the Middle Ages. In parallel is the last peak of microscopic charcoal particles and NPP indicators for dung and erosion.