Climate change versus land management in the Po Plain (Northern Italy) during the Bronze Age : new insights from the VP/VG sequence of the Terramara Santa Rosa di Poviglio

The sedimentary infilling of the moat surrounding the Villaggio Piccolo of the Terramara Santa Rosa di Poviglio was analysed in order to obtain palaeoenvironmental inferences from sediments and pollen assemblage. The high-resolution stratigraphic sequence preserves evidence of the environmental changes that occurred in the Po Plain, in Northern Italy, during the Late Holocene. Our interdisciplinary approach permitted to study climatic and anthropic contributions to the environmental changes in this region. The relationships between these changes and land-use changes were investigated focussing on adaptive strategies of the Terramare people during the Middle and Recent Bronze ages (1550–1170 yr BC). The Terramare are archaeological remains of banked and moated villages, located in the central alluvial plain of the Po river. The Terramara of Santa Rosa consists of two adjoining settlements (Villaggio Grande and Villaggio Piccolo); the moat that separates the two parts of the site is c. 23 m large and reaches a maximum depth of 4 m from the extant ground level. The stratigraphic sequence VP/VG exposed by archaeological excavation inside the moat was sampled for pedosedimentary, thin section, and pollen analyses. Chronology is based on archaeological evidence, stratigraphic correlations and radiocarbon dating. Pedosedimentary features and biological records (pollen of aquatics and algal remains) demonstrate that shallow water, probably subjected to seasonal water-level oscillations, has always been present in the moat. In the lower units of the sequence, the laminations indicate standing water, while occurrence of reworked pollen testified the supply of sediments to the plain from catchment zones located in the Apennine. Open vegetation was widespread; economy was based on wood management, fruit collection on the wild or from cultivated woody plants, crop fields with a fairly diversified set of cereals especially increasing in variety during dryness or phases of water crisis. Probably, grapevines were cultivated near the moat, where the wet habitat was favourable to the growing of wild plants. The extraordinary high-resolution of this sequence makes visible the management of woods (including coppicing) at the Middle Bronze and early Recent Bronze ages. The economy of Santa Rosa di Poviglio should have been probably less based on animal breeding than it was in the other Terramare villages already studied for pollen. This research also confirms the chronological correspondence between an environment stressed by dry conditions and the collapse of the Terramare civilization.