Conservation of Ptilostemon greuteri (Asteraceae), an endemic climate relict from Sicily (Italy): State of knowledge after the discovery of a second population

Ptilostemon greuteri is one of the most endangered and poorly studied woody vascular plant species of the Mediterranean Basin, endemic to Sicily (Italy). Several peculiar traits confer to P. greuteri a character of uniqueness and an enigmatic attractiveness. In fact, at first glimpse the largest in-dividuals of this species remind the most remarkable and peculiar cases of herbaceous genera (e. g., Echium, Senecio) turned woody on insular or insular-like mountain ecosystems. Following the discovery of a second population of this rare species, a project aiming at the study and conser-vation of P. greuteri was set up. We present here updated information on the distribution, con-servation status, biology and ecological requirements of this species. Field surveys supported by drone imagery were carried out to estimate the current range of the two populations. The data obtained allowed to refine the conservation status assessment of the species and to update the distribution pattern of P. greuteri by means of detailed digital maps of each population. Ongoing field investigations currently provide valuable information about the ecological requirements of the species and point out the impact of wildfires on population size and structure. Our research has also highlighted several knowledge gaps that need to be filled to apply more effective con-servation measures. Preliminary results suggest that local topographic and mesoclimatic factors (air humidity and shade) are key variables explaining the persistency and survival of P. greuteri in the area.

Automated summary

Ptilostemon greuteri is an endangered and poorly studied woody plant species in the Mediterranean Basin, particularly endemic to Sicily, Italy. This study aims to investigate and conserve the species by providing updated information on its distribution, conservation status, biology, and ecological requirements. Field surveys and drone imagery were used to estimate the range of the populations, refine the conservation status assessment, and update the distribution pattern. Preliminary results suggest that local topographic and mesoclimatic factors play a key role in the persistence and survival of P. greuteri.