The vegetation of the Borgotrebbia landfill (Piacenza, Italy) : phytosociological and ecological characteristics

Our study aimed to analyse the vegetation of the Borgotrebbia landfill in phytosociological and ecological terms, in order to contribute to the current knowledge of the landfill's vegetation, and to better understand the environmental characteristics of the area, with a view to its restoration. Five vegetation types were identified, all classified into the Stellarietea mediae class that includes annual ruderal communities. Ellenberg's and Landolt's indices shed light on the ecological characteristics of all the vegetation and five typologies. The vegetation of the study area indicates a moderately basic, semi-dry soil, rich in nutrients, low in humus and badly aerated. The high therophyte percentage indicates a stressed environment, the main cause of this stress being a marked edaphic aridity during the dry summer months. In these conditions, annual plants, which complete their life cycle in a short time after the spring precipitations, are favoured. Finally, the species variety within the various typologies of vegetation increases with a decrease in the percentage of species tolerating salts and heavy metals in the soil. As a consequence, this suggests a possible contamination of the soil in some of the areas.