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The second assessment of the threat status of Estonian lichens based on IUCN system was performed in 2019. The main basis for choosing the species to be currently assessed was the list of legally protected lichens and the list of species assigned to the Red List Categories RE–DD in 2008. Species that had been assessed as Least Concern (LC) in 2008 were not evaluated. Altogether, threat status of 229 lichen species was assessed, among them 181 were assigned to the threatened categories (CR, EN, VU), while no species were assigned to the LC category. Compared to the previous red list, category was deteriorated for 58% and remained the same for 32% of species. In Estonia, threatened lichens inhabit mainly forests (particularly dry boreal and nemoral deciduous stands), alvar grasslands, sand dunes and various saxicolous habitats. Therefore, the most frequent threat factors were forest cutting and overgrowing of alvars and dunes (main threat factor for 96 and 70 species, respectfully). Eesti samblike punane nimestik 2019 2019. aastal viidi läbi teistkordne IUCN süsteemil põhinev Eesti samblike ohustatuse hindamine. Hinnati liike, mis on riiklikult kaitstud ning liike, mis 2008. aasta hindamise järgi olid Eestis kas regionaalselt välja surnud, kriitilises seisundis, väljasuremisohus, ohualtid, ohulähedased või puuduliku andmestikuga (kategooriad RE–DD). 2008. a-l kategooriasse Soodsas seisundis (LC) kuulunud liike ei kaasatud uude hindamisse. Kokku hinnati 229 samblikuliigi ohustatust, nendest 181 kuulusid ohustatud kategooriatesse (CR, EN või VU); ükski hinnatud liik ei sobinud kategooriasse LC. Võrreldes eelmise punase nimestikuga tõusis kategooria 58% liikidel ning jäi samaks 32%-l. Ohustatud samblikuliigid asustavad Eestis peamiselt metsi (eriti palu- ja salumetsi), loopealseid, liivikuid ning erinevaid kivi-kasvupindu. Seetõttu on sagedasemad ohutegurid metsaraie ning loodude ja liivikute kinnikasvamine (oluline tegur vastavalt 96 ja 70 liigile).

Although bryophytes and lichens are frequently vital components of aboveground communities, their interrelationships with vascular plant communities are poorly known. We addressed small-scale covariation of vascular plant and cryptogam (bryophytes and lichens) communities during secondary succession from abandoned gravel pit towards thin soil calcareous (alvar) grassland communities. The cover, richness and diversity of vascular plants, bryophytes and lichens were studied. Whereas vascular plants showed the fastest successional dynamics in terms of richness, bryophytes showed a fast successional dynamic in terms of cover and diversity; the establishment of lichens was the slowest. THe cover, richness and diversity of different life forms changed concurrently. There were significant associations among the species composition of all life forms considered. The strongest relationship was found between lichens and vascular plants in mature stages. We conclude that alvar grasslands are certainly an example of a community in which the association between the vascular plant and the cryptogam communities may influence the overall vegetation succession, and the strength of this association increases during secondary succession.

A unique, species-rich and endangered lichen biota can be found on European coastal and inland sand dunes. However, it is increasingly affected by natural succession as well as by anthropogenic disturbances. We studied lichen diversity on the grey dunes and dune heaths of coastal and inland regions of Estonia. A total of 28 study plots were investigated; in each 0.1 ha study plot general environmental variables and anthropogenic disturbances were described and all epigeic lichen species were identified. We found 66 lichenized fungus (lichen) species, including several rare and ten red-listed lichens. Multivariate analysis (DCA, CCA) was performed to examine gradients in species composition and to relate variation in species data to environmental factors. In addition, we used redundancy analysis (RDA) to relate variation in species’ trait composition to environmental factors. Species composition on grey dunes differed significantly from that on dune heaths. The characteristic species for grey dunes are, besides several Cladonia species, foliose lichens, e.g. Hypogymnia physodes, Parmelia sulcata and Peltigera spp. Also species’ traits composition was different for either habitat, indicating that sorediate lichens, foliose lichens, lichens with cyanobacterium as the main photobiont, and sparsely branched Cladonia species dominate on grey dunes, while esorediate, green-algal, crustose and richly branched fruticose lichens are common on dune heaths. Soil pH was the most essential environmental variable for determining both species composition and species’ traits composition. The composition of lichen species was also significantly influenced by forest closeness, soil Mg content and cover of bare sand; the effect of ground disturbances was low compared to the effect of these environmental factors. To protect and conserve the species-rich lichen biota, it is necessary to protect the dune habitats from building activity, to avoid overtrampling in recreation areas and to regularly remove shrubs and trees.

Ten lichenized fungi are reported as new to Estonia: Atla wheldonii, Bacidia coprodes, Bacidina assulata, Bacidina brandii, Candelariella lutella, Gyalidea fritzei, Piccolia ochrophora, Protoparmelia oleagina, Sclerophora amabilis and Strangospora deplanata . One lichenized fungus, Leptogium subtile , has been reported from Estonia earlier, but all the specimens of this species in the herbarium of University of Tartu appeared to be misidentifications; currently the species has one certain locality in Estonia.

Two species of lichenized fungi, Bacidina sulphurella and Xanthomendoza oregana, and three species of lichenicolous fungi are reported as new for Estonia. Cited specimens are kept in the lichenological herbarium of University of Tartu Natural History Museum and Botanic Garden (TU).