EPIPHYTIC LICHEN BIOTA OF PRIELBRUSIE NATIONAL PARK (NORTHERN CAUCASUS, RUSSIA)

We report on the diversity of epiphytic lichens and allied non-lichenised fungi in two forest sites in the Prielbrusie National Park (Northern Caucasus, Russia). Each forest site was represented by a 1-ha square. In Prielbrusie National Park (total area is 1010.2 km(2)), forest vegetation is restricted to the lower-most elevations in the river valleys, and it is represented by coniferous and mixed forests, predominantly with Pinus sylvestris, Betula pendula, and B. raddeana. Despite the long history of lichenological studies in the Prielbrusie National Park, the lichen diversity remained highly underexplored with the total number of 329 known species, including only 76 epiphytes. In the present time-limited study (three days in June 2018), we selected two contrasting forest stands (presumed lichen diversity hot-spots) on the left bank of the River Adyl-Su (1870 m a.s.l.) and River Shkhelda (2010 m a. s.l.). On the two 1-ha plots, we maximised efforts to obtain as complete as possible species lists, including epiphytic and epixylic lichens, allied non- or facultatively lichenised fungi and lichenicolous fungi. In total, we detected 423 species, including 355 species in Adyl-Su site and 267 species in Shkhelda site, while 199 species were recorded on both sites. Our study increased twice the number of known lichen species in the Prielbrusie National Park, i.e. 315 species were new to this area. Six species (Biatoropsis minuta, Buelliella lecanorae, Dactylospora crassa, Miriquidica majae, Stagonospora exasperatulae, Xyleborus sporodochifer) are new to Russia. Seventeen species (Arthopyrenia pithyophila, Asterophoma mazaediicola, Biatora albidula, Calicium pinastri, Catinaria neuschildii, Cladonia glauca, C. polydactyla, Fuscidea pusilla, Gyalideopsis alnicola, Lawalreea lecanorae, Lichenochora polycoccoides, Micarea fallax, Peltigera neocanina, Sarea resinae, Skyttea lecanorae, Thelocarpon laureri, Tremella christiansenii) were found for the first time in the Caucasus. The threatened species Menegazzia terebrata is included in the Red Data Book of Russia. It was found for the first time in the Republic of Kabardino-Balkaria. The diversity of forest epiphytic lichens has already been surveyed in the Western Caucasus (Republic of Adygea) and the Eastern Caucasus (Republic of Dagestan). Lichen communities on the Adyl- Su site are more similar to sites in the Western Caucasus, while the lichen communities on the Shkhelda site are more similar to a site on the Gunib plateau (Eastern Caucasus). The species richness on the Adyl- Su site approaches the highest number reached in the Caucasus: 358 species per 1 ha on the Lagonaki Plateau (Western Caucasus).