Qanat, gebbie and water sources: the last refuge for the malacologican freshwater fauna in Palermo (Sicily, Italy)

Abstract

The surroundings of Palermo were characterized, over the centuries, by the presence of many natural environments of great ecological and faunal importance. These environments were placed in a context characterized by minimal and sustainable urban development and large agriculture areas, dedicated to the development of tree crops such as citrus and orchards. These crops were supported by an imposing irrigation system that, using natural resources such as watercourses, wells and springs, collected and distributed water in soils through tanks, gebbie, qanat, irrigation channels (saje), etc. Fresh water mollusks, like many other animal and vegetable organisms, spread from the natural freshwater environments in this artificial water system, thus creating a unique and varied ecosystem. The subsequent urban development of the city of Palermo and the destruction of many of those natural environments has further enhanced the ecological role of the artificial freshwater systems as an important refuge for the native fauna and flora. In the present study, we report on freshwater molluscs observed in the territory of Micciulla, a large relict area occupied almost entirely by an old citrus, now located inside the city of Palermo. In this area there are some springs, an extensive array of artificial freshwater to irrigate the crops, and the qanat Savagnone located in the “Camera dello Scirocco”. The results obtained by census of different populations of freshwater mollusks confirm the importance of these environments and the growing role they play as the last refuges for fauna and flora originally linked to natural humid environments.