The paper presents the results of the ongoing research of lichen diversity in Arkhangelsk Region of Russia, in Vodlozersky National Park which is the largest protected area in the territory of NW Russia. In total, 155 species of lichens and allied fungi are recorded for the first time for the Arkhangelsk part of the Vodlozersky National Park, and 69 species – for the whole mainland area of Arkhangelsk Region.

The genus Dendriscosticta (Ascomycota: Peltigerales) encompasses several distinctive lichen-forming fungal species restricted to the Northern Hemisphere. Most are flagship species of old-growth forests with good air quality. A global phylogeny of the genus based on multilocus sequence data (ITS, RPB1, EF-1α, MCM7), model-based phylogenetic methods, and morphological and chemical assessments, reveals a high level of cryptic speciation often associated with restricted geographical distribution and/or chemical characters. Using sequence-based species delimitation approaches, we circumscribe two main clades referred to as the D. wrightii clade, with five unequivocal species, including D. gelida sp. nov., and the D. praetextata clade, with eight putative species, including D. phyllidiata sp. nov. The absence of recently collected material of D. hookeri comb. nov. from the type locality unfortunately prevents assignment of this epithet to one of the five supported lineages sharing this morphotype. Three new combinations are proposed: D. hookeri, D. insinuans comb. nov. and D. yatabeana comb. nov. Epitypes are designated for D. wrightii and D. yatabeana. Species diversity within the genus increased from four to nine. Our morphological assessment confirmed that Sticta and Dendriscosticta can be readily distinguished by the presence of excipular algae whereas the structure of the lower surface pores is not a reliable diagnostic feature.

Thirty-one lichen-forming fungi, 12 lichenicolous fungi, and 5 non-lichenized fungi are reported as new for Arkhangelsk Region; 7 species are new for its mainland area. Micarea fallax is reported for the first time for Russia; M. laeta and M. pusilla are new for the European part of Russia. The second finding of Nicropuncta rugulosa for Russia is recorded; microconidia are first observed in this species. The records of ten species which have been included in the new edition of the Red Data Book of the Arkhangelsk Region (2020) are presented. Nephromopsis laureri from the Red Data Book of the Russian Federation (2008) and Leptogium rivulare from the IUCN Red List are reported for the first time for Arkhangelsk Region.

The communities of middle taiga spruce forests (ass. Linnaeo borealis–Piceetum abietis dryopteridetosum var. typica) and secondary communities formed after winter clearcuttings are described (Fig. 1) and classified according Braun-Blanquet (1964) approach using 81 relevés. Ellenberg ecological values (Ellenberg et al., 1991) were used to assess lighting (L), soil moisture (F), acidity (R) and nitrogen (N). The ordination was carried out using the NMS method. Both primary forest and secondary communities are classified as the alliance Piceion excelsae Pawłowskiet al. 1928 within the order Piceetalia excelsae Pawłowski et al. 1928 in the class Vaccinio–Piceetea Br.-Bl. in Br.-Bl.et al. 1939. We described 2 associations (incl.  1 new), 3 subassociations (2 new), 2 varieties (1 new), 2 subvarieties, and 2 communities. Ass. Aulacomnio palustris–Calamagrostietum purpureae ass. nov. hoc loco (Table 2). Nomenclature type (holotypus hoc loco): relevé 16 (field № 26p/20), Komi Republic, Ust-Kulom district, two-year cutting place, swath (61.84083° N 54.33778° E, 16.07.2020, author I. A. Likhanova. Diagnostic species (DS): Aulacomnium palustre, Calamagrostis purpurea, Carex globularis, Chamaenerion angustifolium, Polytrichum commune, Sphagnum angustifolium. The association includes «young» (succession stage 1(2)-17(18) years after cutting) secondary communities, formed at the swaths and skidding trails. The absence of tree stand results in the increased lighting and soil moisture, which explains an invasion of heliophile and water-resistant species of vascular plants and mosses. After cutting, DS of the primary association and subassociation almost disappear, but those of class and order remain. Species number — 23–54, average — 38. There are 2 subassociations within aasociation. Subass. A. p.–C. p. typicum subass. nov. hoc loco (Table 2 relevés 1–16, Fig. 3). Nomenclature type (holotypus hoc loco): relevé 16 (field № 26p/20), Komi Republic, Ust-Kulom district, two-year cutting of spruce herb-bilberry-green moss forest at the swath (61.84083° N 54.33778° E , 16.07.2020, author I. A. Likhanova. No own DS. The subassociation includes communities at the swath and skidding trails of 1(2)-year cutting place with poor species richness in comparison with primary forests. Number of species 20–27, average – 24. Subass. A. p.–C. p. avenelletosum flexuosae subass. nov. hoc loco (Table 2, relevés 17–27, Fig. 4). Nomenclature type (holotypus hoc loco), relevé 25 (field № 13-УК), Komi Republic, Ust-Kulom district, 17-year cutting place, swath (61.99389° N, 54.14778° E , 17.09.2019, author I. A. Likhanova. DS: Avenella flexuosa, Gymnocarpium dryopteris, Rubus arcticus.The subassociation includes communities of swaths and skidding trails at 17(18)-year cutting place enriched by heliophile and water-resistant species. The forming forest environment is the reason of high abundance of forest species and emergence of several diagnostic species of primary association and subassociation. The cutting remains are overgrown by epigeous mosses and lichens. Species number — 24–45, average — 33. Community Carex brunnescens (Table 3, relevés 1–12, Fig. 5). DS: Carex brunnescens (dominant), C. canescens, Ceratodon purpureus, Dicranella cerviculata (dominant). Syntaxon includes communities at the main skidding trail at 1(2)-year cutting place. Despite high abundance of diagnostic species of the ass. Aulacomnio palustris–Calamagrostietum purpureae, we can’t include the relevés into the association due to high diversity of early succession species and low abundance of DS of both the class Vaccinio–Piceetea sylvestris and the order Piceetalia excelsae. There are numerous undergrowth of Betula pubescens (18 thousand ind./ha). Herb-dwarf shrub and moss layers are formed by pioneer, heliophile and water-resistant species. Forest dwarf shrubs, herbs and mosses occur on the litter remnants. Species number — 20–34, average — 27. Community Salix caprea. (Table 3, relevés 13–22, Fig. 6). DS: Agrostis gigantea, A. tenuis, Carex rhynchophysa, Deschampsia cespitosa, Epilobium palustre, Juncus filiformis, Populus tremula, Salix caprea (dominant), S. myrsinifolia, S. phylicifolia, Sphagnum russowii. The syntaxon includes communities at the main skidding trail of 17(18)-year cutting place. The presence of DS of ass. Aulacomnio palustris–Calamagrostietum purpureae and subass. A. p.–C. p. avenelletosum flexuosae as well as the prevalence of water resistant and early succession species and low abundance of DS of class Vaccinio–Piceetea sylvestris and order Piceetalia excelsae are character. Tree stand is formed by young trees of Betula pubescens (mean density is 21 thousand ind./ha). Shrub layer is formed by wiilows. Herb-dwarf shrub layer is dominated by species, preferring water logging, and species of disturbed habitats. Species number — 36–45, average — 40. Subass. Linnaeo borealis–Piceetum abietis dryopteridetosum var. Betula pubescens (Table 1, relevés 13–22). DS: Betula pubescens (dominant), Milium effusum, Rhytidiadelphus triquetrus. The variant includes communities at 48(49)-year cutting place. The tree lyer height and crown density are comparable to those of the indigenous spruce forest, however, the proportion of birch is higher. Vascular plant DS of ass. Linnaeo borealis–Piceetum abietis and subass. dryopteridetosum are registered, but the abundance of moss DS is low. Many forest species become abundant in the herb-dwarf shrub layer. Moss layer is inhibited by leaf litter. Species number — 29–45, average — 36. There are 2 subvarieties: typica (communities at the swath and skidding trails) and Calamagrostis purpurea (main skidding trail). The scheme of vegetation succession after clearcuttings of spruce small herb-bilberry-green moss forests (Linnaeo borealis–Piceetum abietis dryopteridetosum var. typica) (Fig. 10) is made on the results of NMS-ordination (Fig. 9) and the data on the restoration period and preferences of syntaxa to the certain technological elements of the cutting place. The following succession series are described: at the swaths and skidding trails — Aulacomnio palustris–Calamagrostietum purpureae typicum → A. p.–C. p. avenelletosum flexuosae → Linnaeo borealis–Piceetum abietis dryopteridetosum var. Betula pubescens subvar. typica → L. b.–P. a. dryopteridetosum var. typica; at the skidding trails – community Carex brunnescens →community Salix caprea → Linnaeo borealis–Piceetum abietis dryopteridetosum var. Betula pubescens subvar. Calamagrostis purpurea → L. b.–P. a. dryopteridetosum var. typica. In communities of different ages at swaths and skidding trails, the species richness of vascular plants (16–18 species/100 m2) and mosses (8–10 species/100 m2) is lower compare to the primary spruce forest (19 and 14 species/100 m2 respectively). The species richness of vascular plants at 17-year and 48-year communities of the main skidding trails (27 species/100 m2) is higher than in the primary forest due to the invasion of pioneer, meadow and mire species; that of mosses is lower (8–12 species/100 m2). Thus, the cutting has a negative impact on species diversity, which is expressed in forest species loss. The floristic composition of the disturbed forest community is not restored even fifty years after anthropogenic impact.

The purpose of the data paper was to introduce into scientific literature the results of scientific work carried out for the third edition of the 'Red Data Book of the Komi Republic'. The article reflects methodological approaches to the formation of a list of rare and in need of protection species and describes the corresponding datasets published in GBIF. Information about 7,187 occurrences of 438 rare species and infraspecies included in the third edition of the 'Red Data Book of the Komi Republic' have been published.