Terricolous lichens are abundant in semi-arid areas, where they are exposed to high irradiation. Photoprotection is essential for the algae as the photobiont provides the primer carbon source for both symbionts. The UV-protectant lichen metabolites and different quenching procedures of the alga ensure adequate photoprotection. Since the long-term effect of diminishing UV-protectant lichen metabolites is unknown, a major part of lichen secondary metabolites was removed from Cladonia foliacea thalli by acetone rinsing, and the lichens were then maintained under field conditions to investigate the effect on both symbionts for 3 years. Our aim was to determine if the decreased level of UV-protectant metabolites caused an elevated photoprotection in the algae and to reveal the dynamics of production of the metabolites. Photosynthetic activity and light protection were checked by chlorophyll a fluorescence kinetics measurements every 6 months. The concentrations of fumarprotocetraric and usnic acids were monitored by chromatographic methods. Our results proved that seasonality had a more pronounced effect than that of acetone treatment on the function of lichens over a long-term scale. Even after 3 years, the acetone-treated thalli contained half as much usnic acid as the control thalli, and the level of photoprotection remained unchanged in the algae. However, the amount of available humidity was a more critical limiting environmental factor than the amount of incoming irradiation affecting usnic acid production. The lichenicolous fungus Didymocyrtis cladoniicola became relatively more abundant in the acetone-treated samples than in the control samples, indicating a slight change caused by the treatment.

Distribution data originating from earlier herbarium collections and recent biodiversity records form the basis of distribution analyses in lichen species with different ecological requirements, where the records allowed comparisons or showed clear trends. As the occurrences of lichens are strongly correlated to background environmental conditions (e.g., air pollution, global warming), confirmed by Wirth’s ecological indicator values, the analysis of distribution types has a great value for bioindication and the establishment of current and future climatic and pollution situations. Five distribution types were introduced—presented by characteristic examples (13)—according to lichen distribution maps prepared in different periods of time (representing changing environmental conditions): (1) species of decreasing occurrences by time (e.g., Lobaria pulmonaria, Menegazzia terebrata, suboceanic, acidic pollution sensitive species), (2) species with no or few former records but with increasing occurrences in recent decades (e.g., Flavoparmelia soredians, Hyperphyscia adglutinata, Solenopsora candicans, sub-Mediterranean species), (3) species with increasing and then (from c. 2000) decreasing occurrences (e.g., Scoliciosporum chlorococcum, Straminella conizaeoides, acidofrequent species), (4) species with widely increasing occurrences in recent decades (e.g., Physcia aipolioides, Piccolia ochrophora, Xanthoria parietina, nitrofrequent species), and (5) species with rapidly increasing occurrences (e.g., Absconditella lignicola, Coenogonium pineti, Evernia divaricata, rapidly spreading species). The proposed distribution types of lichen species may be applied to wider regions (the European or the global level).

Knowledge of lichenicolous fungi is limited at a worldwide level and needs further basic information, as in the case of Central and Southern Europe. The literature sources for “Revised checklist of the Hungarian lichen-forming and lichenicolous fungi” by Lőkös and Farkas in 2009 contained 54 lichenicolous and other microfungi species of 38 genera. Due to recent field studies and microscopic work, the number of known species has increased to 104 lichenicolous species in 64 genera during the last decade, including 53 new species for the country. Old records of five species were confirmed by new collections. Key characteristics of some of the most interesting species are illustrated by microscopic views and two distribution maps are provided. Recent biodiversity estimates suggest that the number of currently known species could be 1.5 (–2) times higher with more detailed work on field collections. Although lichenicolous fungi have been less well studied in Hungary in the past, the relative diversity of lichenicolous fungi there, as indicated by Zhurbenko’s lichenicolous index, was found to be slightly higher than the mean value calculated for the world.

Shivarov, V. V., Varga, N., Lőkös, L., Brackel, W. v., Ganeva, A., Natcheva, R. & Farkas, E. 2021. Contributions to the Bulgarian lichenicolous mycota – an annotated checklist and new records. – Herzogia 34: 142–153.An annotated checklist of 45 taxa of lichenicolous fungi from Bulgaria is presented. Arthonia parietinaria, Athelia arachnoidea, Cercidospora caudata, C. epipolytropa, Didymocyrtis cladoniicola, Endococcus verrucosus, Illosporiopsis christiansenii, Lichenoconium erodens, L. lecanorae, Pronectria subimperspicua, Pyrenochaeta xanthoriae and Stigmidium tabacinae are reported for the first time from Bulgaria. To assess the expected diversity of lichenicolous fungi in Bulgaria, we applied a Lichenicolous Index (LI) to compare with other regions with better knowledge about lichenicolous mycota. At the current stage of the known number of lichens in Bulgaria we expect between 225 and 315 lichenicolous fungi for the country.