Human-environment interactions in the southern Tyrrhenian coastal area: hypothesis from Neapolis and Elea-Velia

In the last decades, increasing interest in geoarcheology drove the research in deepening the man-environment interaction during historical times. In Campania, a region rich in archeological sites, this multiproxy approach has been giving new interesting results in several sites such as Neapolis and Elea-Velia, two important urban centers of the Greek-Roman periods. Several excavations were realized in the coastal strip of Naples urban area thanks to the realization of the new underground line. The recovery of three Roman shipwrecks together with quay and dredging evidence allowed the existence of the Neapolis harbor to be confirmed and precisely positioned. A huge amount of archeo-stratigraphical data were collected for a time span ranging the last 4000 years. The recent excavation at Elea-Velia highlighted new sedimentary records linked to recurrent flooding episodes which interacted with the human management of the town and its surroundings during a time period ranging from the VI century B.C. to the Late Ancient. Comparison of data collected in the two sites allowed the recognition of significant changes in coastal paleoenvironments as well as in the natural vegetation pattern and land use. The coastal profile of Neapolis before the Greek colonization was characterized by articulated tufaceous rocky cliffs with promontories and inlets. During the Greek and Roman times, port activities developed in the widest and most sheltered bay while coast progradation occurred in other coastal sectors leading to the formation of sand beaches. In Late Ancient times, sediment supply from the catchment area forced the closing of the bay and a further coastal progradation. A similar physiographical pattern characterized the coast of Elea-Velia, built on a rocky hill facing the shore. Since the beginning of the settlement in the VI century B.C., alluvial flooding episodes affected the urban area leading to thick aggradation covering houses and roads of the Hellenistic period. The same alluvial activity characterized the Roman times but with increasing intensity from the III century A.D. onwards. During the intervening periods of stability, repair and rebuilding of houses and roads occurred. The coastal environmental changes highlighted in the study areas have to be considered in a wider landscape system, being surely influenced by the changing land use. The forests covering the surroundings of these towns represented a natural source of timber, while the less steep slopes and piedmont areas were certainly used for arboricultural practices. Horticulture was carried out intra moenia as clearly testified by the last discoveries. Therefore, the intensive deforestation of the watershed feeding the urban areas was the most probable cause of the increasing soil erosion but the concurrent influence of climate has to be taken into account in giving a exhaustive explication to the observed environmental changes. In fact, the paleoclimatic data seem to record, from the III century A.D., a period of transition from wet-warm to dry-fresh which could have enhanced the effects of the anthropic forcing factors.