Controls on late-Holocene drift-sand dynamics: The dominant role ofhuman pressure in the Netherlands

摘要

Holocene drift-sand activity in the northwest European sand belt is commonly directly linked to population pressure (agricultural activity) or to climate change (e.g. storminess). In the Pleistocene sand areas of the Netherlands, small-scale Holocene drift-sand activity began in the Mesolithic, whereas large-scale sand drifting started during the Middle Ages. This last phase not only coincides with the intensification of farming and demographic pressure but also is commonly associated with a colder climate and enhanced storminess. This raises the question to what extent drift-sand activity can be attributed to either human activities or natural forcing factors. In this study, we compare the spatial and temporal patterns of drift-sand occurrence for the four characteristic Pleistocene sand regions in the Netherlands for the period between 1000 BC and AD 1700. To this end, we compiled a new supra-regional overview of drift-sand activity based on age estimates (¹⁴C, optically stimulated luminescence (OSL), archaeological and historical ages). The occurrence of sand drifting was then compared in time and space with historical-route networks, relative vegetation openness and climate. Results indicate a constant but low drift-sand activity between 1000 BC and AD 1000,interrupted by a remarkable decrease in activity around the BC/AD transition. Itis evident that human pressure on the landscape was most influential oninitiating sand drifting: this is supported by more frequent occurrences closeto routes and the uninterrupted increase of drift-sand activity from AD 900onwards, a period of high population density and large-scale deforestation. Oncetriggered by human activities, this drift-sand development was probably furtherintensified several centuries later during the cold and stormier ‘Little IceAge’ (LIA; AD 1570–1850).