Holocene palaeoecology and human-environmental interactions at the coastal Black Sea Lake Durankulak, northeastern Bulgaria

The environmental changes (vegetation history, human impact and land use, influence of the Black Sea) in the area of Lake Durankulak, northeastern Bulgaria, were reconstructed and synthesized for the last ca. 8000 years. The palaeoecological information derived from various proxies (pollen, plant macrofossils, molluscs, sediments) was compared on a regional scale with the evidence from the nearby coastal lakes Shabla-Ezeretz and Bolata. The Early Holocene xerothermic steppe vegetation, dominated by Chenopodiaceae, Artemisia and Poaceae species, and accompanied by stands of trees in moister habitats, was transformed after 6000 cal. BP into a forest-steppe, comprising oak woods with Carpinus betulus, Ulmus, Tilia, Acer. This vegetation pattern has been periodically modified, depleted and replaced by arable land or xerothermic herbaceous communities enriched with anthropophytes and ruderals, particularly after the intensification of human activities since 3300 cal. BP. The archaeobotanical evidence from the region has provided valuable information about the occupation phases and subsistence strategy of the local people since the Late Neolithic (5300 cal. BC/7250 cal. BP). Periods with cultivation of cereals (Triticum, Hordeum) and/or stock-breeding activity were interrupted by abandonment of the settlements and the arable land due to unfavourable environmental changes. The periodical connection/isolation of Lake Durankulak with the Black Sea and the periods of marine influence were recorded by changes in the composition of the fossil molluscan fauna and the lithology of the sediments, and chronologically confirmed by radiocarbon dates. The development of the coastal lakes throughout the largest part of the Holocene has been also considerably influenced by the fluctuations of the Black Sea level.