Land cover and use-history of large empty spaces at fortified Iron Age hilltop sites; a case study from La Terrasse, Bibracte oppidum

Abstract

The research of Iron Age oppida and hillforts plays a significant role in understanding the urbanisation processes throughout the European continent. The habitation and built-up areas have always been in the limelight of both traditional and environmental archaeological research. However, at many oppida, there were also large, unoccupied empty spaces. As they are crucial for understanding these settlements’ internal organisation, their functions are debated. Here we aim to demonstrate that seldom studied archaeobotanical archives preserve information on their use-history. By implementing a multiproxy approach, we seek to answer questions on the development, land use and vegetation history of one important open space at Bibracte oppidum on Mont Beuvray. Through the correlation of pollen, phytoliths, diatoms, charcoal, seeds, and parasites with radiocarbon dating we collected evidence of archaeologically otherwise untraceable human activities and detected a much more complicated history of the studied area. We show that it was repeatedly used in the last eight millennia and was never farmed or built up. During the phases of its most intensive exploitation in the Late Iron Age (La Tène) and Early Middle Ages (Merovingian) periods, it was kept as grassland. Our research lays down the foundation for the wider implementation of archaeobotany into projects that aim to clarify the uses and functions of enigmatic large open spaces, not only from the Iron Age but also from other periods.