Using drone imagery and group field activities for an in-depth investigation of the vascular flora: a case study in the Rocca di Novara Massif (NE Sicily, Italy)

Rocky habitats are suitable refuges for numerous rare and endemic plants. Due to their inaccessibility and the unreliability of traditional survey methods, assessing the survival status of these plants is quite a hard task. In order to address this sampling issue, we employed the drones and carried several field activities to investigate the vascular flora of Rocca di Novara massif located in Northeastern Sicily (NE Sicily hereafter). Located on the southern border of the Peloritani Mountains, Rocca di Novara, also known as Rocca Salvatesta, is a small carbonate massif and it represents one of the highest and most characteristic peaks in NE Sicily. According to our investigation, 300 taxa have been recorded, belonging to 189 genera and 51 different families. The results obtained show the presence of 13 endemic species to Italy (4.3%) and 12 strictly endemic to Sicily (4%). Some taxa of high phytogeographical value have been detected, such as Aubrieta columnae subsp. sicula, Daphne oleoides subsp. oleoides, Edraianthus graminifolius subsp. siculus, Fritillaria messanensis, Odontites bocconei subsp. bocconei, Phelipanche gussoneana, Saxifraga callosa subsp. australis. This latest species was rediscovered after 100 years on the high cliffs of Rocca di Novara thanks to the use of the drone imagery. Our results provide valuable insights into the floristic diversity of Rocca di Novara and offers a solid starting point for further phytogeographical and floristic studies on the vascular plants of the Peloritani district.