The widespread cyanolichen genus Peltigera (Peltigerales, Lecanoromycetes) comprises many insufficiently known, poorly delimited and/or undescribed species. In Estonia, phylogenetic analyses of Peltigera specimens from a wide range of habitat types revealed 31 putative taxa with habitat-specific segregation between the species along several environmental gradients: from humid eutrophic forests to dry oligotrophic forests and grasslands and from alkaline soils of alvar grasslands to acidic soils of conifer forests. The diversity of Peltigera was the highest on roadsides and dunes and the lowest in alvar habitats which, however, supported a unique assemblage of undescribed Peltigera taxa. Deciduous broad-leaved forests, too, included several undescribed or rare and red-listed species. The results demonstrate that, in Estonia, many Peltigera species have narrow habitat requirements and are at present threatened by habitat loss and degradation. For the Nostoc symbionts of the Estonian Peltigera, mycobiont identity was the primary factor determining which Nostoc variant was present in each Peltigera thallus. However, the cyanobiont selectivity did not always reflect phylogenetic relationships among the studied Peltigera species but correlated instead with habitat preferences, and several taxa from different sections of the genus Peltigera were associated with the same Nostoc variants in the same habitat, indicating the presence of photobiont-sharing lichen guilds in the community.
Jüriado I, Kaasalainen U, Jylhä M, Rikkinen J. 2019. Relationships between mycobiont identity, photobiont specificity and ecological preferences in the lichen genus Peltigera (Ascomycota) in Estonia (northeastern Europe). Fungal Ecology 39: 45–54, doi.org/10.1016/j.funeco.2018.11.005.
Jüriado I, Kaasalainen U, Rikkinen J. 2017. Specialist taxa restricted to threatened habitats contribute significantly to the regional diversity of Peltigera (Lecanoromycetes, Ascomycota) in Estonia. Fungal Ecology 30: 76–87, doi.org/10.1016/j.funeco.2017.08.004.
Keywords: cryptic species, habitat ecology, substrate specificity, lichenized fungi, Cyanobacteria, photobiont selectivity, trnL, tRNALeu intron, ITS
