ATENA dataset (Italy). DOI:10.5281/zenodo.15861218 The ATENA database (dATabase of ornamEntal non-NAtive trees of seven Italian cities) was developed within the framework of the National Biodiversity Future Center project aimed at improving knowledge and management of biodiversity in Italy. ATENA compiles comprehensive taxonomic, ecological, and trait data on non-native ornamental trees occurring in public green spaces of seven representative Italian cities: Milan, Turin, Pavia, Asti, Rome, Campobasso, and Palermo. Ornamental non-native trees contribute significantly to urban landscapes by enhancing aesthetic appeal and providing multiple ecosystem services. The database currently includes 317 taxa. ATENA is designed as an essential resource to make freely available taxonomic and ecological features of urban trees in public spaces, and to support urban forestry, green space planning, and biodiversity management, helping prevent the introduction and spread of problematic non-native tree species in urban environments. The dataset consists of four interlinked tables: TAXONOMY: This table contains taxonomic information for each species, including scientific names and nomenclature following World Flora Online (WFO 2024) and Plants of the World Online (POWO 2024), authorship details, accepted names, and family assignments according to the Italian checklist of alien flora (Galasso et al. 2024), along with subsequent updates as continuously integrated into the Portal of the Flora of Italy (2025). It also indicates whether each species is listed in European, national, or regional regulations for non-native plants in Italy (Brundu et al. 2020). ECOLOGICAL_INDICATORS: This table provides ecological indices for each taxon, including Ecological Indicator Values for Europe (EIVEs; Dengler et al. 2023), and additional Ellenberg Indicator Values specifically compiled for the alien vascular flora of Italy (Domina et al. 2018). TRAITS: This table includes a comprehensive set of functional and biological traits for each species. It records plant growth form, dispersal mode, diaspore type, plant height, leaf type, and leaf phenology, as well as leaf area, leaf nitrogen content per mass (Nmass), leaf mass per area (LMA), diaspore mass, and stem specific density (SSD), following Díaz et al. (2022). DISTRIBUTION: This table reports the presence and frequency of each taxon across seven Italian cities (Milan, Turin, Pavia, Asti, Rome, Campobasso, and Palermo), with individual columns for each city. It also includes information on whether the species is considered an archaeophyte or neophyte in Italy (based on Celesti‐Grapow et al. 2009; Galasso et al. 2024), as well as its area and biome of origin (POWO 2024; WFO 2024). References Brundu G, Minicante SA, Barni E, Bolpagni R, Caddeo A, Celesti-Grapow L, Cogoni A, Galasso G, Iiriti G, Lazzaro L, Loi MC, Lozano V, Marignani M, Montagnani C, Siniscalco C. 2020. Managing plant invasions using legislation tools: an analysis of the national and regional regulations for non-native plants in Italy. Annali di Botanica 10, 1-11. https://doi.org/10.13133/2239-3129/16508 Celesti‐Grapow L, Alessandrini A, Arrigoni P, Banfi E, Bernardo L, Bovio M, Brundu G, Cagiotti M, Camarda I, Carli E, et al. 2009. Inventory of the non‐native flora of Italy. Plant Biosyst. 143(2):386–430. https://doi.org/10.1080/11263500902722824 Dengler J, Jansen F, Chusova O, Hüllbusch E, Nobis MP, Van Meerbeek K, Axmanová I, Bruun HH, Chytrý M, Guarino R, et al. 2023. Ecological Indicator Values for Europe (EIVE) 1.0. Vegetation Classification and Survey. 4:7–29. https://doi.org/10.3897/VCS.98324 Díaz S, Kattge J, Cornelissen JHC, Wright IJ, Lavorel S, Dray S, Reu B, Kleyer M, Wirth C, Prentice IC, et al. 2022. The global spectrum of plant form and function: enhanced species-level trait dataset. Sci Data. 9(1). https://doi.org/10.1038/s41597-022-01774-9 Domina G, Galasso G, Bartolucci F, Guarino R. 2018. Ellenberg Indicator Values for the vascular flora alien to Italy. Flora Mediterranea. 28:53–61. https://doi.org/10.7320/FlMedit28.053 Galasso G, Conti F, Peruzzi L, Alessandrini A, Ardenghi NMG, Bacchetta G, Banfi E, Barberis G, Bernardo L, Bouvet D, et al. 2024. A second update to the checklist of the vascular flora alien to Italy. Plant Biosyst. 158(2):297–340. https://doi.org/10.1080/11263504.2024.2320129 Portal to the Flora of Italy. 2024. Portal to the Flora of Italy. Version 2024.2. Available at http:/dryades.units.it/floritaly [accessed: 05/07/2025]. POWO. 2024. Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. Published on the Internet. https://powo.science.kew.org/ Retrieved 30/11/2024. Raunkiær C. 1934. The life forms of plants and statistical plant geography. https://api.semanticscholar.org/CorpusID:129154685 WFO. 2024. World Flora Online. Version 2024.12. Published on the Internet; http://www.worldfloraonline.org Accessed on: 30112024. Funding The work is funded under the National Recovery and Resilience Plan (NRRP), Mission 4 Component 2 Investment 1.4 - Call for tender No. 3138 of 16 December 2021, rectified by Decree n.3175 of 18 December 2021 of Italian Ministry of University and Research funded by the European Union – NextGenerationEU; Project code CN_00000033, Concession Decree No. 1034 of 17 June 2022 adopted by the Italian Ministry of University and Research, CUP H73C22000300001, Hub: Biodiversity, Spoke 5: Urban biodiversity, Project title “National Biodiversity Future Center - NBFC”. The Project is partially funded by PRIN 2022JBP5F8- PREVALIEN. Enhancing Knowledge on Prevention and Early Detection of the Invasive Alien Plants of (European) Union concern in the Italian Protected Areas. CUP Master: J53D2300657-0006