Landsscape diachronic reconstruction in the Tiber Delta during historical time. A holistic approach

The sensitivity of deltas in response to evolutionary factors makes them important archives of the events that occurred in the entire river basin. Detailed knowledge of the stratigraphy and morphology, combined with a set of archaeological, palaeobotanical and historical information, make possible to reconstruct the diachronic changes of the landscape in the Tiber delta plain over the past 3000 years taking into account natural and anthropic forcing. The main factors that contributed to the delta landscape change are considered following a temporal scansion. Among the natural factors, we considered climate, sea level rise, tectonic and local subsidence. Among the human factors we considered the population density and several human activities, such as farming and breeding practices, reclamation, construction of ports, canals and salt works. To evaluate the amount of sediment involved in the delta evolution during different periods, the BQART model was used. Prior to Roman times anthropogenic forcing had a lower influence than natural forcing on the landscape evolution. During the Roman period (between third century BC-fourth century AD), the delta landscape was severely conditioned by the human activity. Throughout the Middle Ages and until the first half of the nineteenth century, a more natural landscape evolved in the delta, gradually and partially replacing the previous landscape. With the arrival of the new Italian State a new and impressive landscape change occurred. The evolution of the Tiber delta landscape appear particularly affected by anthropogenic forcing when socio-political organization allowed the control and planning of policy actions.