After African trades: changing in Cignana landscape between Late Antiquity and Medieval age

In many parts of Sicily, the Late Antiquity represents a period of strong transformation in settlement patterns and landscapes. These changes occur also on an area 20 km SE from Agrigento, on the southern coast of the island: this is the territory around the imperial villa of Cignana (2nd-3th century AD), where the University of Palermo carried out some surveys from 2007. During the surveys more than 30 new topographic units of Late Antiquity were detected: some of them are big and accurately dated, others are small and difficult to interpret. Usually, they are located in easily accessible places, close to springs and the road system. Principally African pottery allows us to follow the transformation and to detect continuity or decline in respect of the previous phases. Some sites already inhabited during the early and middle imperial age endure and grow in size, others disappear. Four of them become large villages between the 5th-6th cent., as shown by the number and variety of African imports, and in some cases persist until the early 7th, albeit reduced. After this moment the settlement patterns change totally: long-life sites are abandoned and the countryside is apparently unpopulated. Feeble traces of life are provided by few sherds of Rocchicella cooking pots (8th - early 9th) and handle with deep groove. What are the causes of this transformation in the Cignana landscape? Could socio-political, economic, or climatic changes explain it? Maybe our knowledge about medieval pottery, especially common ware and local productions, is still too limited to understand these changes?