Epiphytic lichen communities in old-growth beech forests of western Ukraine

Aims : To revise the syntaxonomy of epiphytic lichen communities on Fagus sylvatica from old-growth beech forests in the Carpathians and adjacent uplands, in particular (1) to identify the main syntaxonomic units and reveal their ecologіcal, structural, and compositional peculiarities; (2) to assign the associations to higher-rank syntaxa; (3) to define the position of the resulting syntaxonomic units in the system of syntaxa of lichen communities of Europe; and (4) to evaluate the potential use of epiphytic lichen communities on beech trees as indicators of the ecological integrity of forest habitats. Study area : Ukrainian Carpathians, Roztochchia, Podillia, and Khotyn uplands. Methods : 230 relevés of lichen communities from western Ukraine and data from literary sources (reference data) were classified using the modified TWINSPAN algorithm implemented in JUICE software in two steps, identifying units of higher and then lower rank consecutively. Results : The first step of the analysis resulted in seven clusters which were mainly interpreted as classes or orders. The second step of the analysis resulted in 20 units of association or unranked community level. 12 of these were recorded in the study area and included 267 lichen species. Conclusions : Epiphytic lichen communities on Fagus sylvatica in the old-growth beech forests of Western Ukraine are divided into five classes: Agonimietea repletae (a new class encompassing lichen communities occurring on exposed roots and the bases of old tree trunks with smooth bark), Arthonio radiatae-Lecidelletea elaeochromae , Hypogymnietea physodis , Neckeretea complanatae and Physcietea , and 12 assocations or unranked communities. The order Agonimietalia repletae , the alliances Biatorion radicicolae and Dictyocatenulation albae , and five associations are newly described here. The provisional alliance Biatorion vernalis is proposed for epiphytic lichens on mosses. Taxonomic reference : Nimis et al. (2018). Abbreviations : EUNIS = European Nature Information System; EVC = EuroVegChecklist; ICPN = International Code of Phytosociological Nomenclature; UNESCO = United Nations Educational, Scientific and Cultural Organization; OD = Original diagnosis.