Two Millennia of Landscape Transformation in the Siegerland (Western Germany) as Evidenced by Pollen, Lipid Biomarkers and Archaeological Record

The Siegerland (W-Germany) exhibits distinct phases of intensive metallurgy during the Iron Age (2nd – 1st centuries BC) and Middle Ages (9th – 16th centuries AD) that coincide with landscape transformations and shifts in local subsistence economies. Multi-proxy analyses of alluvial sediments – pollen, non-pollen palynomorphs, coprophilous fungal spores, and lipid biomarkers – provide insights into these land use changes. The pollen record reveals deforestation during the La Tène period and Middle Ages (decrease of arboreal pollen), which is corroborated by n-alkanes (increase of grass-derived homologues). Elevated charcoal and black carbon contents occur particularly during the late La Tène period and reflect the fire history of the study area. Indicators such as Cerealia pollen, weeds, grassland taxa, coprophilous fungal spores and faecal sterols and bile acids document crop cultivation and ruminant livestock during this period. A phase of demographic decline after the La Tène period, lasting around 800 years, is mirrored in reduced sedimentary input. Population growth since 900 AD and the expansion of metallurgical activities triggered human impact once more. Our study highlights the dynamic interplay between metallurgy, landscape transformation and subsistence strategies in the Siegerland and demonstrates the value of interdisciplinary approaches for reconstructing the environmental footprint of past societies over millennia.