The contribution of mollusc shells to the reconstruction of environment at the Early Medieval stronghold of Pszczew (Poland)

Abstract

The Early Medieval stronghold that existed in Pszczew (western Poland) from the 8th to 12th century was located on the shore of Lake Pszczewskie. During archaeological excavations conducted in 2010, systematic sediment samples were taken for malacological analysis to enhance our understanding of the environment in the vicinity of the site during its occupation.Forty taxa found in the samples included remains of land snails and freshwater molluscs. The most abundant among land snails were species characteristic of open and humid habitats, frequently found on the banks of various water bodies. Among freshwater molluscs, species characteristic of shallow and overgrown reservoirs and typical of permanent and stagnant water bodies predominate. Malacological analysis revealed minor changes in local hydrological conditions during the Early Medieval period. From the end of the 8th century until the first half of the 10th century, the area was definitely wet and marshy. Gradual disappearance of freshwater species in favor of land snails characteristic of humid habitats, beginning in the second half of the 10th century, indicate that the area was gradually drying out. Since the 11th century, the environment in the vicinity of the site was not influenced by larger changes. The taxa identified in the sediment profile indicated limited differences between the present-day and Medieval environments.