The rock-faces vegetation of Montecristo Island: insights into the rupicolous communities of the Tyrrhenian Islands (Italy)

Montecristo Island, part of the Tuscan Archipelago National Park and strictly protected since 1971, remains one of the Archipelago’s least studied islands in terms of vegetation. The only detailed phytosociological study, conducted in the 1980s, did not address several sporadic or spatially restricted plant assemblages, particularly those occurring on cliffs. Our study examines and classifies these poorly known communities from floristic, ecological, and phytosociological perspectives, and compares them with analogous vegetation across the Tuscan Archipelago to clarify their syntaxonomic position. Forty relevés were collected in 2023–2024 on rock-face habitats using the Braun-Blanquet method. Multivariate analyses identified three distinct chasmophytic-chomophytic vegetation groups. The first consists of high-elevation, north-facing vertical cliffs dominated by Polypodium cambricum and several Montecristo endemics, including Saxifraga montis-christi and Hieracium racemosum subsp. amideii ; for these stands we propose the new association Saxifrago montis-christi - Polypodietum cambrici . The second, encompasses low-elevation, thermoxerophilous cliff habitats characterized by Anogramma leptophylla and Asplenium obovatum subsp. obovatum , for which we propose the name Anogramma leptophylla and Asplenium obovatum subsp. obovatum community. The third includes shaded cliffs with ample elevation excluding the extremes, dominated by Cymbalaria aequitriloba and Arenaria balearica , corresponding to the association Arenario balearicae-Cymbalarietum aequitrilobae . Although poorer in species compared to the cliff communities of other Tuscan islands, these habitats contain distinctive bryophytes and several endemic or biogeographically important taxa, fitting within EU Habitat 8220. The study closes a major knowledge gap on Montecristo’s rock vegetation and refines the understanding of Tyrrhenian cliff plant communities, proposing syntaxonomical updates above the association level.