Using the Carta della Natura and distribution data of invasive alien plants of (European) Union concern in Sardinia for assessment of impacts in invaded habitats, definition of risk and invasion scenarios, and for drafting dedicated action plans

Article no. 3 of the Italian framework law on protected areas (L. no. 394/91) provides for the creation of a "Carta della Natura" (nature map, hereafter CdN), i.e., a map that "... identifies the state of the natural environment in Italy, highlighting natural values and vulnerability profiles … ". The national coordination of CdN was assigned to ISPRA which over time has defined methods and standards for the elaboration of this tool for the knowledge of the territory, based on the use of reliable basic data available for the national territory and IT/GIS procedures specifically tailored. CdN for the Sardinia Region was created as part of a collaboration between ISPRA, the Sardinian regional Authority for the Environment and the University of Sassari. The works started with a first phase in 2006; subsequently it was completed in 2010. The present contribution aims to explore the potential of applying the CdN in the context of risk assessment and evaluation of negative impacts on habitats, as well as in the definition of strategies for tackling biological invasions, with special concern to the presence and distribution of 5 invasive alien species (IAS) of (European) Union concern pursuant to the Regulation (EU) no. 1143/2014 and subsequent amendments and updates. In fact, we focus on the following 5 species invasive in Sardinia: Ailanthus altissima, Acacia saligna, Cenchrus setaceus, Hydrocotyle ranunculoides, and Pontederia crassipes. From an operational and methodological point of view, the geodatabase with the known distribution records of the 5 IAS in Sardinia was used for a topological overlay with the Sardinian CdN (Habitat map with a precision resolution of 1: 50,000). In this way, the polygons invaded by the different species and the different types of habitats involved were identified. The relationship among invaded habitats and type of invasive species, the expected or realized different types of impacts mechanism according to the EICAT / IUCN classification (e.g., competition, hybridization, disease transmission, changes in combustibility, interaction with other IAS), were assessed and on the basis of existing literature and of expert opinion. impacts on the habitats currently invaded were therefore quantified and spatially mapped. The analysis of the invaded habitats gives the opportunity to evaluate risk for those habitats of the same type that are not yet invaded, producing models for the assessment of the risk of invasion. These models take into concern additional predictors such as distance from areas already invaded, distance from roads, altitude, mode of propagation of the species, propagule pressure. We are convinced that these preliminary results strongly support the usefulness of CdN in the management of plant invasions in Sardinia, with special concern to the invasive alien plants of Union concern.