A multi-staged drift sand geo-archive from the Netherlands: New evidence for the impact of prehistoric land use on the geomorphic stability, soils, and vegetation of aeolian sand landscapes

The drift sand area near Hilversum, the Netherlands, holds a geo-archive with multiple drift sand phases and intercalated palaeosols. We studied this area to test earlier theories on the development of podzols in such aeolian sands, the occurrence of sand drifting, and the contemporary vegetation development, and to gain insight into the early human impacts on these fragile ecosystems. Based on OSL and radiocarbon datings, palae-oecological studies, and soil chemical analyses, the age and origin of the drift sand phases and palaeosols were established. Sand drifting started around 6000 BCE (Late Mesolithic), the drift sand covering a distinct podzol in the Younger Cover Sand II. A second Late Mesolithic drift sand phase dated from ca. 4900-4500 BCE. Three later drift sand phases were distinguished of which the last is the classic Late Medieval (and younger) phase, while the first two date from the Neolithic. All intercalated palaeosols exhibited more or less prominent podzolisation. The palaeocological data showed that, prior to the Neolithic, in the forest open patches had developed with non -arboreal vegetation, dominated by Poaceae and Ericaceae. This changed during the Neolithic, most probably linked to the introduction of crop farming, the vegetation gradually acquiring the characteristics of the classic heathland with patches of trees/shrubs. The early sand drifting, podzolisation and opening of the forest are attributed to Mesolithic land use, with intentional burning as major factor. We conclude that the local destruction of the deciduous forests by fire and associated creation of open patches with bare sand were essential for the early sand drifting and podzolisation to occur. The results shed new light on the origin of drift sands, heathlands, and podzols in the Netherlands, and on the environmental impacts of Mesolithic people, and testify to the fundamental instability of these dry inland dune ecosystems.