Revision of the central Mediterranean xerothermic cliff vegetation

Abstract

Questions: What are the syntaxonomic and synchorological patterns of the xerothermic chasmophytic vegetation in the central part of the Mediterranean Basin? What are the diagnostic species of the high-rank syntaxa of Asplenietalia glandulosi, Onosmetalia frutescentis and Centaureo dalmaticae-Campanuletalia pyramidalis? Location: Mediterranean coastal and subcoastal areas of southern France, and of mainland Greece. Methods: The data set of 1,261 published relevés was analysed using hierarchical clustering (Flexible Beta method), involving a series of data transformations. Indicator species analysis was used to select the best dendrogram solution and identify diagnostic taxa of the main clusters. The dendrogram was interpreted from a syntaxonomic point of view, using nomenclatural type relevés as a basis. The NMDS ordination was performed in order to visualize the floristic relationships among associations and high-rank syntaxa. MRPP was used to test for differences among alliances. Results: The classification revealed four main clusters of relevés representing the chasmophytic vegetation of southern France, Sardinia and the northwestern part of Italy (Asplenienalia glandulosi/Asplenietalia glandulosi), the southwestern part of Italy and Malta (Tinguarrenalia siculae/Asplenietalia glandulosi), the Adriatic Basin area (Centaureo dalmaticae-Campanuletalia pyramidalis) and the southern Balkans(Onosmetalia frutescentis). The NMDS ordination confirmed the overall pattern, while MRPP showed significant differences among the alliances of the above-mentioned orders and suborders. The lists of diagnostic taxa of the high-rank syntaxa were revised according to a supra-national perspective. Conclusions: The new syntaxonomic scheme provides a comprehensive overview of the chasmophytic vegetation of the central part of the Mediterranean Basin. This scheme mostly matches the recently published EuroVegChecklist, but also exhibits important novelties concerning the syntaxonomic position of some alliances (Dianthion rupicolae, Centaureion pentadactyli, Arenarion bertolonii and Caro-Aurinion), and the floristic and chorological relationships among high-rank syntaxa, with new revised sets of diagnostic taxa. This revision might be useful for further small-scale phytosociological studies. | 515 Applied Vegetation Science TERZI ET al. 1 | INTRODUC TI ON Mediterranean cliffs harbour a very specialized flora, comprising many rare and endemic taxa, and are considered a habitat worthy of protection. The Directive 92/43/EEC of the EU Commission lists calcareous and siliceous rocky cliffs with chasmophytic vegetation as habitat types 8,210 and 8,220, respectively. The effective conservation of these habitats could be enhanced by a consistent classification on a supranational scale. The first phytosociological synthesis for the Mediterranean chasmophytic vegetation was provided by Meier and Braun-Blanquet (1934), who coined the class 'Asplenietales rupestris' (recte: Asplenietea trichomanis) and four orders within this class. Three of these o...

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

“…Trinajsti c 1980Trinajsti c , 2008. However, Terzi et al (2018) showed floristic similarities with the associations of the Centaureo-Campanulion alliance, in the Northern Adriatic. These similarities are due to the occurrence of the halophytic taxa recorded in several other cliff associations of the Centaureo-Campanulion.…”

“…Results were interpreted from a syntaxonomic standpoint on the basis of the occurrences of the association type-relev es within the clusters and the set of IndSp associated to each cluster. Diagnostic taxa of the higher syntaxonomic ranks (alliance, order and class) were deduced from the scientific literature (compare Terzi et al 2018).…”

“…The nomenclature of the two orders, Centaureo-Campanuletalia and Moltkietalia petraeae, was reviewed in some recent articles through the validation and/or typification of some syntaxon names (Terzi and Di Pietro 2016. Moreover, in a syntaxonomic revision of the xerothermic chasmophytic vegetation of the central part of the Mediterranean Basin, Terzi et al (2018) defined the syntaxonomic position of the Centaureo-Portenschlagiellion compared with the other alliances occurring in the area. The aim of this article is to revise the synchorological, coenological and floristic features of the associations of the Centaureo-Portenschlagiellion.…”

“…The Micromerio kerneri-Onosmetum dalmaticae was invalidly described by Lovri c and Rac (1987) for the canyons of Zrmanja and Cikola (Northern Dalmatia) and classified in the Edraianthion tenuifolii and Moltkietalia petraeae. This association has been recently moved to the Centaureo-Portenschlagiellion (Terzi et al 2018).…”

“…The syntaxonomy of xerothermic limestone chasmophytic vegetation of the Adriatic area was reviewed by Trinajsti c (1980) who described the order "Centaureo-Campanuletalia", including two alliances, "Centaureo-Campanulion" and "Centaureo-Portenschlagiellion". The latter alliance covers an elongated area in the central and southern part of the eastern Adriatic pertaining to Croatia, Bosnia and Herzegovina; Montenegro and Albania (Jovanovi c et al 1986;Petrovi c et al 2012;Terzi et al 2018). Trinajsti c (1980,2008) classified five associations in the Centaureo-Portenschlagiellion: Portenschlagiello ramosissimae-Campanuletum portenschlagianae, Campanulo pyramidalis-Moltkietum petraeae, Inulo verbascifoliae-Centaureetum cuspidatae, Centaureetum ragusinae and Seslerio robustae-Putorietum calabricae.…”