Middle Bronze Age land use practices in the northwestern Alpine foreland – a multi-proxy study of colluvial deposits, archaeological features and peat bogs
Authors: Scherer Sascha , Höpfer Benjamin , Deckers Katleen , Fischer Elske , Fuchs Markus , Kandeler Ellen , Lechterbeck Jutta , Lehndorff Eva , Lomax Johanna , Marhan Sven , Marinova Elena , Meister Julia , Poll Christian , Rahimova Humay , Rösch Manfred , Wroth Kristen , Zastrow Julia , Knopf Thomas , Scholten Thomas , Kühn Peter 
Published: June 2021

Abstract. This paper aims to reconstruct Middle Bronze Age (MBA; 1600–1250 BCE)
land use practices in the northwestern Alpine foreland (SW Germany, Hegau).
We used a multi-proxy approach including the analysis of biogeochemical
proxies from colluvial deposits and buried topsoils in the surroundings of
the well-documented settlement site of Anselfingen and off-site pollen data
from two peat bogs. This approach allowed for in-depth insights into the MBA
subsistence economy and shows that the MBA in the northwestern Alpine
foreland was a period of establishing settlements with sophisticated land
management and land use practices. The reconstruction of phases of colluvial
deposition was based on ages from optically stimulated luminescence (OSL)
and radiocarbon (AMS14C) dating from multi-layered colluvial deposits
and supports the local archaeological record with the first phase of major
colluvial deposition occurring during the MBA followed by phases of
colluvial deposition during the Iron Age, the Medieval period and modern
times. The on-site deposition of charred archaeobotanical remains and animal
bones from archaeological features, as well as polycyclic aromatic
hydrocarbons (PAHs), charcoal spectra, phytoliths, soil microstructure,
urease enzymatic activity, microbial biomass carbon (Cmic) and heavy
metal contents from colluvial deposits, were used as proxies for on-site and
near-site land use practices. The charcoal spectra indicate MBA forest
management which favored the dominance of Quercus in the woodland vegetation in
the surrounding area north of the settlement site. Increased levels of
5β stanols (up to 40 %) and the occurrence of pig bones (up to 14 %) support the presence of a forest pasture mainly used for pig farming.
In the surrounding area south of the settlement, an arable field with a
buried MBA plow horizon (2Apb) could be verified by soil
micromorphological investigations and high concentrations of grass
phytoliths from leaves and stems. Agricultural practices (e.g., plowing)
focussed on five staple crops (Hordeum distichon/vulgare, Triticum dicoccum, Triticum monococcum, Triticum spelta, Triticum aestivum/turgidum), while the presence of stilted
pantries as storage facilities and of heat stones indicate post-harvest
processing of cereal crops and other agrarian products within the
settlement. In the area surrounding the settlement, increased levels of
urease activity, compared to microbial biomass carbon (up to 2.1 µg N µg Cmic-1), and input of herbivorous and omnivorous animal
faeces indicate livestock husbandry on fallow land. The PAH suites and their
spatial distribution support the use of fire for various purposes, e.g., for
opening and maintaining the landscape, for domestic burning and for
technical applications. The off-site palynological data support the observed
change in on-site and near-site vegetation as well as the occurrence of
related land use practices. During the Early and Middle Bronze Age, fire
played a major role in shaping the landscape (peak of micro-charcoal during
the MBA), and anthropogenic activities promoted Quercus-dominated forest ecosystems
at the expense of natural beech forests. This indicates a broader regional
human influence in the northwestern Alpine foreland at low- and mid-altitude
inland sites during the Middle Bronze Age.