Digitization and geolocation of specimens from Italian lichen herbaria

An exhaustive taxonomic and biogeographic knowledge is important for developing effective conservation strategies targeted to both species and ecosystems. Poor datasets undermine any modeling approach on biodiversity, reducing the reliability of results and, ultimately, preventing the building of awareness on the threts to which biodiversity is exposed. Natural history specimens are an invaluable source of falsifiable data on the presence of taxa in space and time, so that their digitization is fundamental for building a reliable knowledge-base on the changes in biodiversity during the last 2-3 centuries. While retrieving species occurrence data from digitized natural history collections, some intrinsic challenges need to be addressed, mainly the difficulty of properly geo-referencing a posteriori each record, and the need of revising the identification of ancient specimens on the light of recent taxonomic knowledge. A relevant effort for geo-referencing occurrence records from the digitization of natural history collections of lichens in Italy has recently started. The work was limited to modern herbaria, thus reducing the need of taxonomic investigations for many specimens. Digitized occurrence records of specimens from 11 Italian lichen herbaria were geo-referenced in Decimal Degrees (WGS84). For each record, coordinates and uncertainty of the point were estimated, on the basis of information from the original label. All occurrence records which were already geo-referenced using different reference systems were converted to Decimal Degrees (WGS84). A simplified data-structure was adopted for all herbaria, which will permit an easy updating of the general database by the curators of the individual herbaria. On May 30, 2022, 58.942 records were geo-referenced. They cover all Italian administrative regions and 76% of the taxa hitherto known to occur in Italy. These data, which will be published online in the form of dot-maps, will be freely downloadable in csv format (following the Darwin Core standard) from a new version of ITALIC, the information system on Italian lichens, released in June 2022.