Genus Dimerella (Coenogoniaceae, lichenized Ascomycota) in Slovakia

The genus Dimerella, comprising ca 25 species worldwide, was studied to clarify its occurrence in Slovakia. The paper, based on literature review, revision of collections (BP, BRA, PR, PRC, SAV, W, herb. Vfezda, herb. Pi{út) and fieldwork, brings together evidence of two species, D. pineti and D. lutea. The first voucher specimens and published data for D. pineti date back to the second half of 19th century; 20th century records are only occasional, therefore the species was regarded as rare. However, this investigation shows that it is widely distributed throughout Slovakia, mainly on tree bases, stumps or mossy soil in forests. The sub-oceanic D. lutea is recorded from Slovakia for the first time. Its historical occurrence in the Vihorlat Mounts complements our current observation in the Eastern Carpathians (Bukovské vrchy Mts) in 2002. From an investigation of its ecological requirements, it is evident that the species is confined to humid, well preserved forest biotopes. Within the studied territory the species has not been overlooked, but is extremely rare, which is the reason for including it in the Red List of Lichens of Slovakia as critically endangered. Vernacular names for both the species are introduced

Vitality of the cyanolichen Peltigera praetextata exposed around a cement plant (SW Slovakia): a comparison with green algal lichens

The suitability of the cyanolichen Peltigera praetextata (Sommerf.) Zopf as indicator of the effects of air pollution around a cement industry was investigated. For this purpose, lichen samples taken from an unpolluted site were exposed for 1–6 months at selected sites (a cement mill, two quarries, inhabited and agricultural sites) in SW Slovakia: physiological parameters and ultrastructural features were examined prior and after exposure. The responses of P. praetextata were then compared with those of the green-algal lichens Evernia prunastri and Xanthoria parietina co-located at the same sites. The performance of the cyanobacterial photobiont of P. praetextata (as reflected by the maximum quantum yield of primary photochemistry FV/FM and by the performance index PIABS) was negatively influenced mainly by the length of exposure in the urban and agricultural sites and less by dust pollution around the cement mill and the quarries. A significant increase in membrane lipid peroxidation products reflected the effects of oxidative stresses in all sites. The alteration of the content of water soluble proteins was detected in the samples exposed around the cement mill, while dehydrogenase activity did not show any significant pattern. Similarly to green algal lichens, ultrastructural alterations featured lipid droplets increase, swelling of cellular components, thylakoid degeneration and sometimes plasmolysis, which on the whole gave the cells an aged appearance, especially in the urban and agricultural sites. On the whole, E. prunastri confirmed to be the most sensitive to dust pollution, P. praetextata was likely influenced by microclimatic conditions and habitat eutrophication and X. parietina was the most resistant. When compared with green-algal lichens, P. praetextata was not the best indicator of the effects of cement dust pollution

Impact of forest management on threatened epiphytic macrolichens: evidence from a Mediterranean mixed oak forest (Italy)

Forest management practices may heavily affect epiphytic cryptogams. This study was conceived in March 2016, as soon as we were informed about an authorized logging for timber within a Mediterranean mixed oak forest in Tuscany (central Italy), which threatened a large population of the forest macrolichen Lobaria pulmonaria (L.) Hoffm., composed of hundreds of fertile thalli. Lobaria pulmonaria is often used as an ecological indicator of high quality habitats hosting rare lichens, and in general, cryptogams worthy of conservation. The species has suffered a general decline throughout Europe as a consequence of air pollution and intensive forest management, and currently it is red-listed in several countries, where it is considered also as a “flag species”. We estimated that 40% of the lichen biomass (8.5-12.3 kg ha-1) has been lost due to logging operations (in the core area, up to 1.8 kg every 100 m2), in particular large and fertile thalli. One year after the conclusion of logging operations, the analysis of chlorophyll fluorescence emission (indicator of the photosynthetic performance of the lichen photobionts), revealed a significant reduction of the vitality of the thalli on retained-isolated trees. The article provides issues for conservation in Mediterranean oak forests and outlines the outmost importance of ensuring the safeguard of forest ecosystems hosting fertile populations of this model species, especially in the case of unprotected forests