An unexpected increase in the known populations of the steno-endemic Galium litorale Guss. (Rubiaceae) in southwestern Sicily

Following our recent discovery of approximately 250 populations of the Sicilian steno-endemic Galium litorale Guss. (Rubiaceae) in the area of Mazara del Vallo (Trapani, Sicily, Italy), further targeted field surveys carried out between April and May 2026 have led to the identification of five previously unknown populations in the localities of La Sciumara, Roccolino Soprano, La Muntagna, Dattilo, and Bucàri. These new findings add a total of 94 population nuclei, expanding the known distribution range of this near-threatened species. Overall, the total number of known populations of G. litorale in south-western Sicily increases from approximately 250 to 344. Notably, this study reports for the first time the occurrence of G. litorale under previously unreported nurse species, including Quercus ilex, Rhamnus oleoides subsp. oleoides, Olea europaea var. sylvestris, Cytisus cf. infestus, and Foeniculum vulgare, providing new insights into the species’ ecological requirements. While these discoveries are encouraging for the conservation of the species, they underscore the urgent need for active habitat protection measures, as all newly discovered sites are currently unprotected and vulnerable to fires, grazing, and land abandonment.