A new plant association of the alliance Saxifragion australis described by drone-based phytosociology in northeastern Sicily (Peloritani Mountains)

Abstract

Although the chasmophytic vegetation of Sicily has been examined previously, it remains insufficiently explored due to the formidable challenges associated with accessing vertical cliff habitats. This study employed drone-based surveys combined with Braun-Blanquet methodology to investigate cliff vegetation in the Peloritani and Madonie Mountains. High-resolution aerial imagery enabled species identification and cover estimation on inaccessible rock faces. Twenty-three new relevés were combined with 33 literature records for multivariate analysis. Cluster analysis and DCA revealed floristic differentiation between Peloritani and Madonie phytocoenoses, contrasting with communities from Apennines that we used as an outgroup. We describe Athamanto siculae-Saxifragetum australis for the calcareous cliffs of Rocca Salvatesta (Peloritani), characterized by Athamanta sicula , Hypochaeris laevigata , and Saxifraga callosa subsp. australis . Additionally, we propose to change the name Asperuletum gussonei to Cynanchicetum gussonei for the high-elevation vegetation of the Madonie dominated by Cynanchica gussonei . Drone methodology proved effective for documenting cliff vegetation, offering a safe and replicable approach for advancing phytosociological knowledge in extreme habitats. This research contributes to the syntaxonomic revision of Mediterranean chasmophytic vegetation within the alliance Saxifragion australis .

Code and data availability

The paper's drone-based phytosociological relevé dataset (the plant cover/trait measurements underlying the classification and DCA analysis) is published as Supplementary table S1 under an open license. Supplementary figure S1 is only an ordination diagram, and no author analysis code or raw drone imagery is stated to