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.

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 paper presents the results of continuing research of lichen diversity in rocky communities of Windy Belt Ridge (Arkhangelsk Region, NW Russia). Using the method of sample plots and linear routes, the communities of the mountain Vysokaya (Volda) were examined, and 270 species and 2 subspecies of lichens and allied fungi were recorded there. A total of 18 lichens are new for the mainland area of Arkhangelsk Region, 35 species are new to the Vodlozersky National Park (Arkhangelsk part) and 9 species are in the Red Data Book of Arkhangelsk Region (2020). Within sample plots (altogether 0.2 ha), 230 species were found, with 41–50% of total species number being presented within one sample plot (0.04 ha). Along the linear route (2 km), 190 taxa were recorded: 43 species were found only on the route (outside the sample plots), which is 16% of the total lichen species number in studied communities. Comparative analysis of the lichen diversity between currently studied mountains (Olovgora, Muroigora, Vysokaya) of the Windy Belt Ridge showed that the high degree of community conservation, rocky type of communities with significant rocky outcrops, as well as landscape heterogeneity determine conditions for a high species diversity of lichens. In total, 343 species of lichens and allied fungi have been found for the studied mountains of the Windy Belt Ridge.

The paper presents the first data on lichen diversity in the Kenozersky National Park (Arkhangelsk Region, Northwest Russia). As a result of the study, 263 species and 1 subspecies of lichens and allied fungi were found in the southern part of the national park. Seventeen lichen species are reported for the first time for Arkhangelsk Region. Biatora albidula is a new species for Northwest European Russia. Two recorded species are included in the Red Data Book of Russian Federation and 7 in the Red Data Book of Arkhangelsk Region. Pycnothelia papillaria can be recommended for inclusion to the Red Data Book of Arkhangelsk Region.