Mycolichenological portrait of alder forest: alpha diversity revealed in 1ha plot in the Samursky National Park (Republic of Dagestan, Russia)

Aim. Xylobiont fungi and lichens determine the sustainability of forest ecosystems, but their species richness and taxonomic diversity depend on the forest type and the degree of its disturbance. Alder forests, characterised by a specific set of ecological conditions, represent poorly studied habitats in terms of myco‐ and lichenobiota. The aim of this work was to determine the species composition of aphyllophoroid fungi and epiphytic lichens on a 1 ha sample plot in a lowland floodplain forest dominated by Alnus glutinosa in the Delta Samura area of the Samursky National Park. The authors collected basidiomata of lignicolous fungi and lichen specimens on a sample plot of 1 ha during field studies. The surveyed forest area is represented by a community dominated by Alnus glutinosa and lianas. The material was identified using light microscopy techniques and a standard set of chemical reactions. Thirty‐three species of aphyllophoroid fungi (Basidiomycota) and 53 species of lichens and allied fungi (Ascomycota) were identified. Among them, 16 species (48 %) of aphyllophoroid fungi were recorded for the first time for the Samursky National Park, including six species revealed for the first time for the Republic of Dagestan, of which three species (Donkia pulcherrima, Phanerochaete cumulodentata and Sertulicium granuliferum) were new to the Northern Caucasus. Lichen species Arthothelium ruanum, Bacidia arceutina and Graphis pulverulenta are listed for the first time for the Republic of Dagestan. At the same time, 21 species of lichenized fungi were recorded for the first time on Alnus glutinosa within the region. The taxonomical structure of aphyllophoroid fungi revealed reflects the spring period of basidiomata‐based field study. The predominance of corticioid fungi and revealing hydnoid species among morphological groups may be indicative of the generally wetter habitats of alder forests in comparison to other forest types distributed in the studied area. Most of species were recorded on dead wood of Alnus glutinosa as the main forest‐forming tree. At the same time, each of other substrates (Carpinus betulus and Corylus avellana) turned out to be the habitat of species new to the region. The group of fungal species developing on large‐scale substrate units, represented by fallen trunks, was the most prevalent and is to be considered as more vulnarable in a case of anthropogenical habitat disturbance. The majority of epiphytic lichens discovered on alder are not specific to this woody substrate, except for single findings. These species belong to epiphytes inhabiting the Samur forest, the core of the lichenobiota of which is composed of thermophilous lichens of lowland deciduous forests. In our opinion, the relict character of the forest, which is an isolated and rather small forest massif with relatively homogeneous climatic conditions, causes a high similarity between the species composition of lichens revealed in the surveyed sample plot with Alnus glutinosa and previously studied plots dominated by Carpinus betulus, Populus alba, and Quercus robur.