DataLake: a georeferenced dataset of vascular plants from freshwater lakes of central-southern Italy

Freshwater lakes are fundamental ecosystems that provide essential ecosystem services for humans and support high plant diversity, often including specialized and rare species. Nevertheless, in Italy, botanical knowledge of lake ecosystems remains fragmented, and floristic data are scattered across heterogeneous sources. DataLake is a dataset designed to integrate and standardize existing floristic knowledge on aquatic and riparian vascular plants occurring in 30 natural freshwater lakes of central-southern Italy. Records included in DataLake derive from both literature sources and original field surveys conducted by the authors. Overall, DataLake comprises 5140 georeferenced floristic records referring to 213 taxa, 97 genera and 43 families. The dataset highlights a markedly uneven distribution of taxa and records among lakes, with large tectonic and volcanic basins accounting for the highest floristic richness and number of records. The taxonomic composition is dominated by Cyperaceae, Potamogetonaceae and Juncaceae, while at the species level Myriophyllum spicatum L., Ceratophyllum demersum L., Phragmites australis (Cav.) Trin. ex Steud., Potamogeton perfoliatus L. and Stuckenia pectinata (L.) Börner are the most frequently recorded taxa. A substantial proportion of taxa is included in regional (39% of the dataset) and national (10.8%) conservation risk categories, underlining the role of lacustrine ecosystems as important reservoirs for plant species of conservation concern. Alien species were recorded in 14 lakes, and among these, 12 taxa are classified as invasive, including Paspalum distichum L., Elodea canadensis Michx. and Bidens frondosa L.. Biological and chorological spectra reflect the strong ecological dependence of lacustrine plant species on hydrological conditions, with dominance of hydrophytes and helophytes and multizonal taxa. By integrating heterogeneous floristic data into a single, coherent and openly accessible resource, DataLake provides a solid reference base for future floristic research, as well as for supporting long-term monitoring activities and actions aimed at conserving natural Mediterranean freshwater lake ecosystems