Sedimentation as geomorphological bias and indicator of agricultural (un)sustainability in the study of the coastal plains of South and Central Italy in antiquity

Abstract

Environmental research of ancient landscapes in the coastal plains, river valleys and uplands of the Mediterranean shows how erosion and sedimentation studies play a significant role in the evaluation of the archaeological record at the regional and local scales. As a rule, directors of landscape archaeological projects nowadays involve physical geographers in order to study erosion and sedimentation as potentially influential post-depositional processes that may expose or cover up archaeological remains (long) after regions or sites were abandoned. This is a phenomenon in the literature known as geomorphological bias, i.e. bias caused by landscape taphonomic processes. Key question here is to what extent archaeological settlement patterns are an artefact of landscape change, with deposition obscuring large parts of the ancient Mediterranean landscape. At the same time, it is important for our knowledge of past societies to establish whether these landscape processes affected the sustainability of the human environments of sites and regions already while they were settled, and how people adapted to environmental changes in accordance with the socio-political and socio-economic context. Sustainability is defined in this paper as the capacity of a rural economy to endure in a given environmental and socio-economic setting. A key question from this perspective is whether erosion and sedimentation studies can help explain why some rural landscapes in the long run were economically more viable than others. Drawing on case studies from landscape archaeological and excavation projects of the Groningen Institute of Archaeology, this paper approaches Mediterranean sedimentation history in South and Central Italy from the angles of geomorphological bias and sustainability studies. The focus is on the coastal plains of the Sibaritide in South Italy and the Pontine plain in Central Italy, both of which have been subject to profound landscape changes caused by sedimentation starting at least in the Bronze Age, and caused by erosion in their hinterlands as the result of long term human impact in combination with climatic changes, sea-level change and neotectonics. Although already settled in pre- and protohistory, both coastal plains were targeted for the first time during phases of Greek and Roman colonization as areas of organized agricultural expansion (see Table 1 for a chronological overview of archaeological periods). However, in both cases long term sustainable exploitation proved difficult due to a complex of environmental, technological, socio-economic, and political factors.