Pollen and Molecular Biomarkers from Sedimentary Archives in the Central Po Plain (N Italy): Assessing Their Potential to Deepen Changes in Natural and Agricultural Systems

Abstract

This paper proposes to improve the information provided by biological indicators from sedimentary archives by integrating biomolecular techniques and botanical skills. This study represents a first proposal for combining pollen and biomolecular markers to detect land use and improve knowledge of past environmental change drivers. The specific aim of the research is to verify the relationship between miliacin (a pentacyclic triterpene methyl ether, usually interpreted as a broomcorn millet biomarker) and Panicum pollen in three near-site stratigraphic sequences of the Terramara S. Rosa di Poviglio (Po Plain, N Italy). The three cores span the last ~15,000 years and potentially record the beginning of Panicum miliaceum cultivation attested in the area since at least the Bronze Age within the Terramare culture. Despite the fact that Panicum pollen grains were rare in the spectra and miliacin was barely detectable in most of the 31 samples selected for biomolecular analyses, their combined evidence testifies to the local presence of the plant. Panicum pollen and sedimentary miliacin suggest the adoption of millet crops during the Recent Bronze Age by the Terramare culture, when climatic instability led to the diversification of cereal crops and the shift to drought-tolerant varieties.