Citizen Science in action: tracking species of (European) Union concern through the “AilantItaly” project

In recent years, Citizen Science (CS) has become increasingly important for monitoring biodiversity and its pressures and threats, such as invasive alien species. In the European, some of the invasive alien species with the greatest impact on biodiversity are listed under the Regulation (EU) No. 1143/2014, which requires all Member States to conduct management actions, including continuous monitoring. This monitoring is essential to identify new invasion foci (early warning) for potential eradication, as well as heavily invaded areas, where management and containment measures must be implemented. This study aims to implement a national-scale CS initiative (AilantItaly) to enhance knowledge on the ecology, distribution, and spread of the invasive species Ailanthus altissima (Mill.) Swingle in Italy. Through active public engagement and collaboration among 15 research institutions and organizations, the project, launched within the framework of the TESO working group (Tavolo ESOtiche – UniMiB and UniMoRe) under the National Biodiversity Future Center (NBFC), seeks to collect large-scale occurrence data to support early detection, detailed mapping and modelling, and the development of targeted management strategies. Data are collected and shared through a dedicated project, AilantItaly, launched on March 15th, 2025, on the iNaturalist platform (https://www.inaturalist.org/projects/ailantitaly), a global biodiversity data repository. The initiative promotes active and structured monitoring in urban, natural, and semi-natural environments. By comparing Ailanthus altissima records on iNaturalist before and after the launch of AilantItaly, we explored and provided evidence of: (i) the effectiveness of CS in enhancing spatial and ecological knowledge of the target species at a national scale in Italy, and (ii) the identification of geographic areas with higher susceptibility to invasion, based on citizen-contributed data. Combining scientific rigour with participation, the project fosters dialogue between academia and society, showcasing how CS contributes to addressing invasive species challenges.