Syntaxonomic revision of chasmophytic vegetation of the Centaureo cuspidatae-Portenschlagiellion ramosissimae (Southeastern Adriatic)

The Centaureo-Portenschlagiellion describes the cliff vegetation of the Southeastern Adriatic. This habitat type harbours many endemic taxa and has a high value for biodiversity conservation. Notwithstanding its importance, knowledge of the syntaxonomy of this alliance is still poor. This article aims at revising the synchorological, coenological and floristic relationships of the associations of the Centaureo-Portenschlagiellion. The revision is based on a data set of 103 relev es of Mediterranean xerothermic cliffs from Croatia, Bosnia i Herzegovina and Montenegro. The relev es were clustered by using the Flexible beta method. An indicator species analysis was used to identify the diagnostic taxa of the main clusters of relev es and non-metric multidimensional scaling ordination was undertaken to visualize the floristic relationships among them. Results revealed that only seven associations belong to the Centaureo-Portenschlagiellion, whereas the others already described in phytosociological literature were invalidly described or should be treated as syntaxonomic synonyms of the previous ones. Two associations (Inulo-Centaureetum cuspidatae and Portenschlagiello-Campanuletum portenschlagianae) were reduced to the rank of subassociations of the Moltkio-Inuletum verbascifoliae. Two other subassociations were described for the first time. Data provided with this revision may be considered as essential base-line information that should aid in evaluating the state of this vegetation type in the future.