Holocene transformation of natural steppe into an agricultural landscape in the Polabí and Pojizeří Lowlands, Czech Republic, based on mollusc evidence

Abstract

Recent zonal steppes of Eastern Europe and South-West Asia have their origin in the glacial steppe with its specific continental climate. The westernmost edge of the steppe belt in Central Europe has been climatically shifted from a continental course during the Last Glacial to a rather oceanic one during the Holocene. Steppe enclaves could survive only locally in the driest parts of this area, but as we have confirmed, early arrival of Neolithic agriculture played a significant role in their preservation as well. While pollen analyses can provide the main pattern of landscape development, mollusc successions provide more information about landscape details we need for a better understanding of a steppe transformation towards the recent agricultural ecosystems. Based on the study of 18 mollusc successions in two neighbouring lowlands in the chernozems and alluvial areas of Central and North Bohemia, we described a postglacial development of these two climatically different agricultural landscapes. Based on mollusc evidence, we illustrated the impoverishment of forest communities and the continual occurrence of open habitats throughout the forest climatic optimum of the Holocene. Since the Neolithic colonisation, several erosion events were observed in many profiles documented by a lack of preserved fossil molluscs and layer redeposition which are in excellent agreement with the reconstruction of the fluvial sedimentation and vegetation in the Elbe River floodplain and with the continual settlement of this area. Because we have evidence of a fully developed forest fauna in the Eem interglacial from the Polabí lowland we know that the impoverishment of forest communities and the occurrence of open habitats during the interglacial forest climatic optimum is characteristic only of the Holocene.