Periodic Reporting for period 1 - Cyanolichens (Genetic diversity of cyanobacterial symbionts of lichens and of free-living populations of Nostoc in biological soil crust communities of threatened alvar grasslands)
Reporting period: 2015-06-15 to 2017-06-14
Using nucleotide differences in the tRNALeu (UAA) intron more than 30 different symbiotic Nostoc genotypes were identified. In studied habitats we found the highest number of symbiotic Nostoc haplotypes in alvar grasslands and dunes. However, genetic diversity of Nostoc haplotype was the highest in roadside grassland and on ground of eutrophic forest. Some Peltigera taxa associated with a single or a few closely related Nostoc genotypes, others were generalists, being able to associate with a spectrum of different Nostoc genotypes. The association of different Nostoc haplotypes of studied Peltigera taxa is not necessarily correlated with mycobiont taxonomy instead seems to be correlated to environmental factors.
In addition, environmental factors and ground disturbance affecting the composition of species and functional traits of ground layer lichens on grey dunes and dune heaths of Estonia were analyzed. Several Peltigera species were revealed to be characteristic species for grey dunes and lichens with cyanobacterium as the main photobiont favored grey dune habitat. It was concluded that to protect and conserve the species-rich lichen biota, it is necessary to protect the dune habitats from building activity, to avoid over trampling in recreation areas and to regularly remove shrubs and trees.
Locality data of rare and protected species (Peltigera, Solorina) will be deposited and stored in EELIS (Estonian Nature Information System). Moreover, the evaluation of host tree preferences of red-listed epiphytic lichens, including cyanolichens, was performed. The highest number of red-listed species were accounted for Fraxinus excelsior, Quercus robur and Populus tremula. It was revealed, that several taxa, mainly the cyanolichens, prefer P. tremula to other trees, confirming its high importance as phorophyte species for the threatened epiphytes. Populus tremula can be conisidered as the best possible altervnative phorophyte for the gratest part of threatened lichen species that are growing on temperate broad-leaved trees.
Species of Peltigera are conspicuous and easily recognizable at genus level. Although the recognition of many species is challenge due to the complicated/unresolved taxonomic problems, this genus includes also some very distinctive and easily recognizable species. Those species have rather distinct habitat preferences and therefore they could use for evaluation of qualities of habitats. As most of the cyanolichens that are already defined as indicator species in hemi-boreal region have declined tremendously due to environmental pollution and habitat degradation, therefore this genus could include applicable species for environmental monitoring or diversity hotspots. Lichens are well known example of bioindicators of the environmental conditions is recognized even beyond the scientific community. A strong decrease in species richness has brought biodiversity on the political agenda on national and international levels. Thus the ""proper"" delimitation of species is of great value for recognize the valuable habitats in the region. This is the basic knowledge to build the governmental policies for nature conservation practices."