2024/11/05 by Vasheniak, Iuliia, Willner, Wolfgang, Didukh, Yakiv +2
#Alysso alyssoidis-Sedion alliance #Alysso-Sedetalia order #Carpathian- Pannonian region #FOS: Biological sciences #calcareous vegetation #vegetation classification
paper · doi:10.14471/2024.44.006
Pioneer plant communities dominated by therophytes, succulents, bryophytes and lichens on base- rich substrata of the Alysso-Sedion alliance are endangered and highly important for biodiversity protection. This study aims to revise previous syntaxonomic concepts and provide a unified classi- fication of the Alysso-Sedion communities in the northern part of the Carpathian-Pannonian region, Bohemian Massif, western Ukraine, Romania and Moldova. We extracted relevés dominated by annuals, succulents, bryophytes, and lichens from the European Vegetation Archive. We also selected nomenclatural types of 12 associations reported within the Alysso-Sedion alliance in the study area. Using a classification expert system, we selected an initial dataset of 10,211 relevés of annual and succulent vegetation. We resampled the initial dataset within geographical strata and obtained a dataset of 620 relevés, which we classified using the modified TWINSPAN algorithm. The TWINSPAN classi- fication resulted in 19 clusters. We removed 11 clusters interpreted as outliers or non-target vegetation types and interpreted the remaining eight clusters as the associations Alysso petraei-Sedetum hispanici, Alyssetum muralis, Saxifrago tridactylitae-Poetum compressae, Alysso alyssoidis-Sedetum, Aurinio saxatilis-Allietum podolici, Cerastietum pumili, Sedo albi-Allietum montani and Sempervivetum sobo- liferi. The communities are differentiated along the gradients of nutrients, temperature and light availability. We provide the first unified international classification of the Alysso-Sedion alliance that includes Ukrainian and Moldovian communities. This classification largely corresponds to the existing classifications published in the vegetation monographs of Austria, the Czech Republic, Slovakia, Poland, Romania, Ukraine and Moldova.