Syntaxonomic revision and floristic characterization of the phytosociological alliances corresponding to subalpine and alpine grasslands of the Pyrenees and Cantabrian Mountains (classes Caricetea curvulae, Carici-Kobresietea, and Festuco-Seslerietea)

In this study, we made a numerical revision of the eight phytosociological alliances belonging to the classes Caricetea curvulae Br.-Bl. 1948, Carici rupestris-Kobresietea bellardii Ohba 1974, and Festuco-Seslerietea Barbero & Bonin 1969. This analysis was designed to reveal the significant alliances corresponding to alpine and subalpine grasslands, review the associated syntaxonomical hierarchy, and establish the diagnostic floras of these alliances. The study area comprised the subalpine and alpine vegetation belts of the Pyrenees and the Cantabrian Mountains (northern Spain and southern France). We used 2259 floristic releves, downloaded from the Sistema de Informacion de la Vegetacion Iberica y Macaronesica database, for statistical treatment. First, we classified the dataset, using the K-means clustering technique, so as to reveal a syntaxonomical structure. Second, we calculated the fidelity index Ochiai in all classification partitions. Finally, we compared the obtained lists with community descriptions from four bibliographical references. As a result, we could provide a diagnostic flora for every alliance. Therefore, we reconstructed seven of the eight alliances described. The numerical and bibliographical lists of characteristic species were similar for most syntaxa. Moreover, we proposed some new diagnostic species. Some alliances were considered more statistically robust than others. Finally, syntaxonomical repercussions have been suggested.