Josef P. Halda

Climate change is accelerating the melting of glaciers to create new habitats colonized by pioneer organisms. Lichens are adapted to extreme conditions and, together with cyanobacteria and algae, are generally among the first organisms to appear in primary succession. The exact mechanism of lichen community formation and the factors influencing species turnover are still poorly understood. The aim was to determine the time zones of succession of terricolous and saxicolous species after glacier retreat, and to identify common ecological traits among pioneer species, including thallus type. Additionally, lichen species were categorized into time periods based on their colonization rates. Finally, differences among dated plots in the glacier forelands of Midtdalsbreen (Norway) and Storglaciären (Sweden) were compared. Taxon: Lichens. Location: Arctic. A total of 27 plots (135 subplots) were delineated across five successional age classes (9–264 years postglaciation). Lichen abundances and environmental variables (e.g., orientation, substrate composition) were recorded. Canonical correspondence analysis (CCA) and detrended correspondence analysis (DCA) were used to analyze species composition gradients and the effect of successional age. Monte Carlo permutation tests were performed to determine statistical significance (499 permutations). Lichen species richness increased rapidly in the early succession (15–25 years), but stagnated or slightly declined in older stages (> 100 years), probably due to competitive displacement. Early successional pioneer species included Stereocaulon alpinum , Cetraria islandica , and Flavocetraria nivalis —fruticose lichens that disperse easily by wind through thallus fragments. Late successional species, such as Arctoparmelia centrifuga and Fuscidea kochiana , thrived under stabilized and nutrient‐enriched conditions. CCA showed that successional age explained 12.9% of the variability in species composition, whereas geographic differences contributed 7.9%. Species turnover was influenced by substrate characteristics (fine‐particle sediment vs. coarse rocky substrate), competition, and erosion, which was still shaped by environmental stability. Lichen succession follows the expected pattern, primarily shaped by terrain microtopography, climate, and substrate type. To refine the successional dynamics of lichen communities and other groups of organisms involved in the colonization of newly deglaciated habitats, more long‐term studies from different regions will be needed.

Epiphytic fruticose lichens are not typical organisms for cities. They are sensitive to air pollution, which is higher in urban areas. Lichens are therefore used as bioindicators. Each lichen has different requirements for living, so it would be good to find out how many species of epiphytic fruticose lichens occur in the given city and which environmental variables influence them most, apart from air pollution. Therefore, these issues became the main objectives of this study. Brno was chosen for several reasons, but mainly because there is currently insufficient data on the occurrence of these lichens. A total of 30 sites were studied in Brno, which were divided into three categories (forests, parks, and orchards). The results show acceptable conditions for the growth of six species (Evernia prunastri, Pseudevernia furfuracea, Ramalina farinacea, Usnea dasopoga, Usnea hirta, Usnea subfloridana) in Brno. These species were most commonly found on fruit trees. Canopy openness and the amount of dead wood in the locality had a statistically significant effect on their growth.

In the present paper four new records of lichenicolous species of Arthonia Ach. are reported from India. Arthonia aspiciliae is growing on the thallus and ascomata of Aspicilia sp., Arthonia destruens on the thallus of Physcia stellaris, Arthonia hawksworthii on the thallus of Dimelaena sp. and Arthonia protoparmeliopseos on the thallus and apothecial discs of Protoparmeliopsis muralis. Brief descriptions, illustrations, distributions, hosts and an artificial key to all known lichenicolous species of Arthonia from India is also provided.

The new genus and species, Jejulea byssolomoides, is described from Jeju Island, Korea. This lichen is characterized by saxicolous, crustose, pale greenish-gray, partly finely filamentous, matt, smooth thallus, prominent convex brown to dark brown ascomata with a concolorous margin constricted at the dark brown base, 300–800 μm diameter, 200–250 μm high, without a distinct proper margin, adhering to the substratum ending in a minute byssoid white external part of cylindrical cells, fusiform 3–5 septate ascospores (17–23 × 4–5 μm). Phylogenetic analyses using ITS and mtSSU sequences place Jejulea in the Pilocarpaceae (Lecanorales). The new taxon is closely related to Byssoloma, a cosmopolitan group of foliicolous lichens, which is most diverse in the tropics. Like Byssoloma, Jejulea also forms a byssoid apothecial margin.

Aim: Natural disturbances influence forest structure, successional dynamics and consequently, the distribution of species through time and space. We quantified the long‐term impacts of natural disturbances on lichen species richness and composition in primary mountain forests, with a particular focus on the occurrence of endangered species.Location: Ten primary mountain spruce forest stands across five mountain chains of the Western Carpathians, a European hotspot of biodiversity.Methods: Living trees, snags and downed logs were surveyed for epiphytic and epixylic lichens in 57 plots. Using reconstructed disturbance history, we tested how lichen species richness and composition was affected by the current forest structure and disturbance regimes in the past 250 years. We also examined differences in community composition among discrete microhabitats.Results: Dead standing trees as biological legacies of natural disturbances promoted lichen species richness and the occurrence of threatened species at the plot scale, suggesting improved growing conditions for rare and common lichens during the early stages of recovery post disturbance. However, high‐severity disturbances compromised plot‐scale species richness. Both species richness and the number of old‐growth specialists increased with time since disturbance (i.e., long‐term uninterrupted succession). No lichen species was strictly dependent on live trees as a habitat, but numerous species showed specificity to logs, standing objects or an admixture of tree species.Conclusions: Lichen species richness was lower in regenerating, young and uniform plots compared with overmature and recently disturbed areas. Natural forest dynamics and its legacies are critical to the diversity and species composition of lichens. Spatio‐temporal consequences of natural dynamics require a sufficient area of protected forests for provisioning continual habitat variability at the landscape scale. Ongoing climatic changes may further accentuate this necessity. Hence, we highlighted the need to protect the last remaining primary forests to ensure the survival of regionally unique species pools of lichens.

Two new species, Thelopsis ullungdoensis and Phylloblastia gyeongsangbukensis are described from Ullung-Do (Island), South Korea. The closest relatives from Europe and Korea are epiphytic Thelopsis flaveola which differs by their immersed or semi-immersed yellow ascomata, ascospores without halo and their habitat of smooth bark (mainly Fagus) in humid and cold climates. Thelopsis gangwondoensis differs by its bigger semi-immersed ascomata (600–700 µm in diam.), oblong halonate ascospores (8–12 × 6–8 µm) and its habitat of smooth bark of deciduous trees. P. gyeongsangbukensis differs from its relatives within the genus in having 5-septate ascospores (22–26 × 6–8 µm), semi-immersed, subglobose ascomata with a flattened top (250–400 µm) and a thin, matt, uneven gray-brown to gray-green continuous thallus without isidia.