Abstract: Biological soil crusts (biocrusts) cover about 12% of the Earth’s land masses, thereby providing ecosystem services and affecting biogeochemical fluxes on a global scale. They comprise photoautotrophic cyanobacteria, algae, lichens and mosses, which grow together with heterotrophic microorganisms, forming a model system to study facilitative interactions and assembly principles in natural communities. Biocrusts can be classified into cyanobacteria-, lichen-, and bryophyte-dominated types, which reflect stages of ecological succession. In this study, we examined whether these categories include a shift in heterotrophic communities and whether this may be linked to altered physiological properties. We analyzed the microbial community composition by means of qPCR and high-throughput amplicon sequencing and utilized flux measurements to investigate their physiological properties. Our results revealed that once 16S and 18S rRNA gene copy numbers increase, fungi become more predominant and alpha diversity increases with progressing succession. Bacterial communities differed significantly between biocrust types with a shift from more generalized to specialized organisms along succession. CO2 gas exchange measurements revealed large respiration rates of late successional crusts being significantly higher than those of initial biocrusts, and different successional stages showed distinct NO and HONO emission patterns. Thus, our study suggests that the photoautotrophic organisms facilitate specific microbial communities, which themselves strongly influence the overall physiological properties of biocrusts and hence local to global nutrient cycles.

Abstract: Lichen symbioses develop long-living thallus structures even in the harshest environments on Earth. These structures are also habitats for many other microscopic organisms, including other fungi, which vary in their specificity and interaction with the whole symbiotic system. This contribution reviews the recent progress regarding the understanding of the lichen-inhabiting fungi that are achieved by multiphasic approaches (culturing, microscopy, and sequencing). The lichen mycobiome comprises a more or less specific pool of species that can develop symptoms on their hosts, a generalist environmental pool, and a pool of transient species. Typically, the fungal classes Dothideomycetes, Eurotiomycetes, Leotiomycetes, Sordariomycetes, and Tremellomycetes predominate the associated fungal communities. While symptomatic lichenicolous fungi belong to lichen-forming lineages, many of the other fungi that are found have close relatives that are known from different ecological niches, including both plant and animal pathogens, and rock colonizers. A significant fraction of yet unnamed melanized (‘black’) fungi belong to the classes Chaethothyriomycetes and Dothideomycetes. These lineages tolerate the stressful conditions and harsh environments that affect their hosts, and therefore are interpreted as extremotolerant fungi. Some of these taxa can also form lichen-like associations with the algae of the lichen system when they are enforced to symbiosis by co-culturing assays.

Abstract: Summary An understanding of how biotic interactions shape species’ distributions is central to predicting host–symbiont responses under climate change. Switches to locally adapted algae have been proposed to be an adaptive strategy of lichen-forming fungi to cope with environmental change. However, it is unclear how lichen photobionts respond to environmental gradients, and whether they play a role in determining the fungal host's upper and lower elevational limits. Deep-coverage Illumina DNA metabarcoding was used to track changes in the community composition of Trebouxia algae associated with two phylogenetically closely related, but ecologically divergent fungal hosts along a steep altitudinal gradient in the Mediterranean region. We detected the presence of multiple Trebouxia species in the majority of thalli. Both altitude and host genetic identity were strong predictors of photobiont community assembly in these two species. The predominantly clonally dispersing fungus showed stronger altitudinal structuring of photobiont communities than the sexually reproducing host. Elevation ranges of the host were not limited by the lack of compatible photobionts. Our study sheds light on the processes guiding the formation and distribution of specific fungal–algal combinations in the lichen symbiosis. The effect of environmental filtering acting on both symbiotic partners appears to shape the distribution of lichens.

Abstract: The Antarctic Peninsula, a tundra biome dominated by lichens and bryophytes, is an ecozone undergoing rapid temperature shifts. Such changes may demand a high physiological plasticity of the local lichen species to maintain their role as key drivers in this pristine habitat. This study examines the response of net photosynthesis and respiration to increasing temperatures for three Antarctic lichen species with different ecological response amplitudes. We hypothesize that negative effects caused by increased temperatures can be mitigated by thermal acclimation of respiration and/or photosynthesis. The fully controlled growth chamber experiment simulated intermediate and extreme temperature increases over the time course of 6 weeks. Results showed that, in contrast to our hypothesis, none of the species was able to down-regulate temperature-driven respiratory losses through thermal acclimation of respiration. Instead, severe effects on photobiont vitality demonstrated that temperatures around 15°C mark the upper limit for the two species restricted to the Antarctic, and when mycobiont demands exceeded the photobiont capacity they could not survive within the lichen thallus. In contrast, the widespread lichen species was able to recover its homoeostasis by rapidly increasing net photosynthesis. We conclude that to understand the complete lichen response, acclimation processes of both symbionts, the photo- and the mycobiont, have to be evaluated separately. As a result, we postulate that any acclimation processes in lichen are species-specific. This, together with the high degree of response variability and sensitivity to temperature in different species that co-occur spatially close, complicates any predictions regarding future community composition in the Antarctic. Nevertheless, our results suggest that species with a broad ecological amplitude may be favoured with on-going changes in temperature.

Abstract: Plants regulate soils and microclimate, provide substrate for heterotrophic taxa, are easy to observe and identify and have a stable taxonomy, which strongly justifies the use of plants as bioindicators in monitoring and conservation. However, insects and fungi make up the vast majority of species. Surprisingly, it remains untested whether plants are strong predictors of total multi-taxon species richness. To answer this question, we collected an extensive data set on species richness of vascular plants, bryophytes, macrofungi, lichens, plant-galling arthropods, gastropods, spiders, carabid beetles, hoverflies and OTU richness from environmental DNA metabarcoding. Plant species richness per se was a moderate predictor of richness of other taxa. Taking an ecospace approach to modelling, the addition of plant-derived bioindicators revealed 1) a consistently positive effect of plant richness on other taxa, 2) prediction of 12-55% of variation in other taxa and 48 % of variation in the total species richness.

Abstract: Fungal communities play critical roles in maintaining the structure and function of biocrust in desert ecosystems. However, the successional changes of fungal communities along the biocrust development stages are not fully understood. In this study, we investigated the fungal community compositions inhabiting different biocrust successional stages (bare sand, algal crusts, lichen crusts, and moss crusts) and their relationships with environmental factors in the Gurbantunggut Desert of Northwestern China. Our results showed that fungal diversity did not change significantly along the successional stages. However, fungal biomass in lichen and moss crusts was significantly higher than those in bare sand and algal crusts. Fungal communities also showed significant successional changes with biocrust development from bare sand, algal crusts, lichen crusts, to moss crusts. At the class level, algal and lichen crusts were dominated by Dothideomycetes, Eurotiomycetes, and Lecanoromycetes, while moss crusts were dominated by unidentified Ascomycota, Eurotiomycetes, and Dothideomycetes. Successional changes also occurred at genera level. The dominant OTUs were affiliated to unknown genera in Pleosporales, Humicola, and unknown genera in Chaetomiaceae in bare sand; Endocarpon, unknown genera in Pleosporaceae, and Humicola in algal crusts; Endocarpon, Heteroplacidium, and unknown genera in Lecanorales in lichen crusts; and Heteroplacidium, Endocarpon and unknown genera in Pleosporales in moss crusts. Changes in soil organic C, conductivity, and soil bulk density were associated to the shifts in fungal community compositions, suggesting that the accumulations of soil nutrients and salts may drive the changes in biocrust fungal compositions.

Abstract: Lichens are often highlighted as important life forms in the early evolution of terrestrial vegetation. They have been postulated to go as far back as the early Proterozoic, suggested as a model to classify Ediacaran macrofossils, presumed to have existed as protolichens in the Early Phanerozoic, reconstructed as precursors of major clades of higher Fungi, or proposed to have evolved multiple times in or after the Carboniferous. We provide a critical review of these hypotheses, based on fossil and molecular evidence and a newly reconstructed molecular timeline of major ekaryotic lineages, pointing out that presumed lichen fossils must be assessed in light of the definition of the lichen symbiosis; that is, the presence of fungal (hyphal) and microalgal (or cyanobacterial) elements in a stable association rather than morphological, taphonomic, or ecological features, unless classifiable within extant lichens due to their morphology. Excluding 32 genera of Ediacaran macrofossils, an updated list of 236 presumed lichen fossils is presented. Of these, 14 cannot be verified, 10 are ambiguous in their biological status, and 22 must be rejected, in addition to all Ediacaran macrofossils. This leaves 190 accepted lichen fossils, most of which (90%) are from Paleogene amber. The oldest unequivocal lichen fossil belonging in an extant class is Honeggeriella complexa from the Early Cretaceous, whereas Chlorolichenomycites salopensis and Cyanolichenomycites devonicus are accepted as lichen-like fossils representing presumably extinct lineages unrelated to extant lichens. A new molecular timeline, using nuclear small subunit data across major kingdoms, tests calibrations with enigmatic fossils by estimating the Eukaryote crown divergence, discussing artifacts that may lead to temporal compression of terminal clades and consequently to errors in calibrations when using recent fossils. Based on this, the Ascomycota-Basidiomycota split occurred about 630 Ma in the Ediacaran, whereas the Lecanoromycetes, the oldest clade of lichen-forming fungi, originated 306 Ma in the Carboniferous. Besides the ascomycete fossil Paleopyrenomycites, the recently discovered mushroom Gondwanagaricites is identified as the fungal fossil with the best divergence estimate of the Eukaryote root. The Ediacaran lichen hypothesis put forward by Gregory Retallack is largely rejected due to an inappropriate definition of lichens based on taphonomy and substrate ecology. In contrast, the protolichen hypothesis, formally proposed by Ove Eriksson, has merit in postulating evolutionary experiments with lichenization in early-diverging fungi and fungal-like organisms. However, such lineages, if they existed, did not give rise to extant lichen fungi, and early terrestrial vegetation reconstructed from biochemical signatures in the Proterozoic and Early Cambrian must not necessarily have included lichens or lichen-like life forms. The finding that important fungi including the genera Aspergillus and Penicillium may be derived from lichenized ancestors is revisited; this unique topology, not confirmed in subsequent studies, has been caused by a single contaminant sequence, highlighting the potential impact of problematic sequence data. Yet the close relationship between lichen formers in class Lecanoromycetes and medically and economically fungi in Eurotiomycetes is now firmly established. Recent work shows that extant lichens evolved multiple times within the Ascomycota and Basidiomycota, likely since the Carboniferous, with initial lichenization largely correlating with humid, tropical paleoclimates. Possible radiations of early rock-dwelling lichens occurred in the Permian and Triassic, whereas largely epiphytic macrolichens of temperate and tropical montane ecosystems evolved predominantly in the Paleogene. We conclude that there is no solid evidence that lichens may have played a major role in reconstructing early life on land, although the prospect is intriguing. More effort needs to be focused on assessing the fossil record, and ancient fossils should not forcibly shoehorned into known clades and life forms using questionable analogies with extant organisms.

Abstract: The Antarctic–South American bank-forming moss Chorisodontium aciphyllum is known for having the oldest sub-fossils of any extant plant in Antarctica as well as extreme survival abilities, making it a candidate species for possible long-term survival in Antarctica Applying phylogeographic and population genetic methods using the plastid markers trnL-F and rps4 and the nuclear internal transcribed spacer, we investigated the genetic diversity within C aciphyllum throughout its range Low genetic variation was found in all loci, both between and within Antarctic and southern South American populations, suggesting a relatively recent (likely within the last million years) colonization of this moss to the Antarctic, as well as a likely severe bottleneck during Pleistocene glaciations in southern South America We also performed a simple atmospheric transfer modeling approach to study potential colonization rates of small (microscopic/microbial) or spore-dispersed organisms (such as many mosses and lichens) These suggested that the northern Antarctic Peninsula shows potentially regular connectivity from southern South America, with air masses transferring, particularly southbound, between the two regions We found elevated genetic variation of C aciphyllum in Elephant Island, also the location of the oldest known moss banks (> 5500 years), suggesting this location to be a genetic hotspot for this species in the Antarctic

Abstract: Biological soil crusts (biocrusts) play numerous crucial roles in drylands, which comprise over 40% of Earth’s terrestrial surface. Among these key contributions is the fixation of atmospheric nitrogen. Yet, relatively little is known about the N2 fixation capabilities of different lichen species that are found in late successional biocrust communities across drylands globally. In order to improve our species-specific understanding of biocrust lichen N2 fixation, we collected biocrusts dominated by four common species of lichens – Collema spp., Gyalolechia desertorum, Psora decipiens, and Squamarina lentigera – that represent a range of lichen families and morphological types. Nitrogenase activity of the biocrust community dominated by these lichens was evaluated using the acetylene reduction assay. Additionally, biocrust community composition was assessed using the point-intercept method along transects at varied distances from exposed bedrock. As expected, Collema spp.-dominated biocrusts had the highest rates of nitrogenase activity, with rates up to seven times larger than those of the other three target species. Nitrogen concentrations and carbon:nitrogen ratios of lichen tissue differed among lichen species. However, when the composite biocrust profile was assessed (i.e., biocrust tissue, microbial cells, and mineral soil to a 2 cm depth) these among-species differences in total nitrogen disappeared. Community composition changed according to distance from exposed bedrock, with a higher diversity of lichens closer to the bedrock. Multiple drivers, including climate and land use change, affect biocrust community composition and species-specific functional information, even within a group such as late successional biocrusts, could help in forecasting the potential effects of global change on N2 fixation, and consequently, soil fertility in drylands.

Abstract: We lack studies evaluating how the identity of plant, lichen and moss species relates to microbial abundance and soil functioning on Antarctica. If species identity is associated with soil functioning, distributional changes of key species, linked to climate change, could significantly affect Antarctic soil functioning. We evaluated how the identity of six Antarctic plant, lichen and moss species relate to a range of soil attributes (C, N and P cycling), microbial abundance and structure in Livingston Island, Maritime Antarctica. We used an effect size metric to predict the association between species (vs. bare soil) and the measured soil attributes. We observed species-specific effects of the plant and biocrust species on soil attributes and microbial abundance. Phenols, phosphatase and β-D-cellobiosidase activities were the most important attributes characterizing the observed patterns. We found that the evaluated species positively correlated with soil nutrient availability and microbial abundance vs. bare soil. We provide evidence, from a comparative study, that plant and biocrust identity is associated with different levels of soil functioning and microbial abundance in Maritime Antarctica. Our results suggest that changes in the spatial distribution of these species linked to climate change could potentially entail changes in the functioning of Antarctic terrestrial ecosystems.

Abstract: Stand structure, mean tree age, deadwood amount and microclimate all change markedly in the course of natural forest dynamics. The last remaining primeval forests of the temperate forest biome are valuable study objects to investigate the effects of forest dynamics and management on forest structure and function as well as phytodiversity, which is not sufficiently understood. Three pairs of Fagus sylvatica primeval and production forests in eastern Slovakia were selected for studying the effects of natural forest development stages on vascular plant, bryophyte, and lichen species richness and composition. We further compared the diversity patterns in the initial, optimal and terminal stages of forest development with those of nearby production forests. The plot‐level species richness of epiphytic bryophytes and lichens increased from the initial to the terminal stage, but only lichens exhibited a significantly higher cumulative species richness (γ diversity) in the later (optimal and terminal) stages. No increase in species richness from the initial to the terminal stage was found for deadwood‐inhabiting epiphytes and the ground‐layer vascular plants. Canonical correspondence analyses identified characteristic bryophyte and lichen species for the different development stages, while the bulk of vascular ground layer species occurred across all stages with no stage preference. Stem diameter was an even more important driver of epiphyte diversity and species composition than the development stage. All stages of the primeval forests (including the initial) were more species‐rich in epiphytes and, when investigating larger plot numbers, also in vascular plants than the production forests. Synthesis. In primeval forests of European beech, plant species richness did not differ significantly between the consecutive forest development stages, while species composition did. This is attributable to the small‐scale mosaic structure of the forest, rapid gap closure by beech, and the continuity of deadwood across the stages, which reduces spatio‐temporal differences in microhabitat availability in the forest. Bryophytes and lichens are species‐richer, and vascular plants at least similarly rich, in the primeval as compared to the production forests, if the study area is sufficiently large.

Abstract: Five lichen species of Cladonia genus (C. fimbriata, C. furcata, C. subulata, C. foliacea and C. rangiferina) were examined. We described the chemical composition of the acetone extracts of the mentioned lichens and the antioxidant, antimicrobial and antitumor activities of their extracts. The phytochemical analysis was determined by HPLC-UV method. The depside (atranorin), depsidones (hypoprotocetraric acid and fumarprotocetraric acid) and dibenzofurane (usnic acid) were identified from these lichens. Antioxidant activity was evaluated by measuring the scavenging capacity of tested samples on 2,2diphenyl-1-picrylhydrazyl (DPPH) radicals, reducing power of samples and determination of total phenolic and flavonoid compounds in extracts. As a result of the antioxidant activity C. furcatа showed the largest effect. The minimum inhibitory concentration (MIC) against five bacterial and 10 fungi was established. The extract of lichen C. fimbriata showed the strongest antibacterial activity (MIC values ranging from 0.625 to 20 mg/mL) while, extract of the lichen C. subulata showed the strongest antifungal activity (MIC values were 0.625 20 mg/mL). Cytotoxic activity was tested using 3-(4,5dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method and all samples were found to be strong anticancer activity toward used cell lines with IC50 values ranging from 11.69 to 140.13 μg/mL.

Abstract: Species circumscription is key to the characterization of patterns of specificity in symbiotic systems at a macroevolutionary scale. Here, a worldwide phylogenetic framework was used to assess the biodiversity and symbiotic patterns of association among partners in trimembered lichens from the genus Peltigera, section Chloropeltigera. We sequenced six loci of the main fungal partner and performed species discovery and validation analyses to establish putative species boundaries. Single locus phylogenies were used to establish the identity of both photobionts, Nostoc (cyanobacterium) and Coccomyxa (green alga). Distribution and specificity patterns were compared to the closely related clade, section Peltidea, which includes mainly Peltigera species with trimembered thalli. For section Chloropeltigera, eight fungal species (including five newly delimited putative species) were found in association with nine Nostoc phylogroups and two Coccomyxa species. In contrast, eight fungal species (including three newly delimited putative species) in section Peltidea were found in association with only four Nostoc phylogroups and the same two Coccomyxa species as for section Chloropeltigera. This difference in cyanobiont biodiversity between these two sections can potentially be explained by a significantly higher frequency of sexual reproductive structures in species from section Chloropeltigera compared to section Peltidea. Therefore, horizontal transmission of the cyanobiont might be more prevalent in Chloropeltigera species, while vertical transmission might be more common in Peltidea species. All Peltigera species in section Chloropeltigera are generalists in their association with Nostoc compared to more specialized Peltigera species in section Peltidea. Constrained distributions of Peltigera species that associate strictly with one species of green algae (Coccomyxa subellipsoidea) indicate that the availability of the green alga and the specificity of the interaction might be important factors limiting geographic ranges of trimembered Peltigera, in addition to constraints imposed by their interaction with Nostoc partners and by climatic factors.

Abstract: Lichens have been extensively studied and described; however, recent evidence suggests that members of the bacterial community associated with them could contribute new functions to the symbiotic interaction. In this work, we compare the nitrogen-fixing guild associated with bipartite terricolous lichens with different types of photobiont: Peltigera cyanolichens and Cladonia chlorolichens. Since cyanobacteria contribute nitrogen to the symbiosis, we propose that chlorolichens have more diverse bacteria with the ability to fix nitrogen compared to cyanolichens. In addition, since part of these bacteria could be recruited from the substrate where lichens grow, we propose that thalli and substrates share some bacteria in common. The structure of the nitrogen-fixing guild in the lichen and substrate bacterial communities of both lichens was determined by terminal restriction fragment length polymorphism (TRFLP) of the nifH gene. Multivariate analyses showed that the nitrogen-fixing bacteria associated with both types of lichen were distinguishable from those present in their substrates. Likewise, the structure of the nitrogen-fixing bacteria present in the cyanolichens was different from that of chlorolichens. Finally, the diversity of this bacterial guild calculated using the Shannon index confirms the hypothesis that chlorolichens have a higher diversity of nitrogen-fixing bacteria than cyanolichens.

Abstract: In this study, we explored the diversity of green algal symbionts (photobionts) in sympatric populations of the cosmopolitan lichen-forming fungi Thamnolia and Cetraria. We sequenced with both Sanger and Ion Torrent High-Throughput Sequencing technologies the photobiont ITS-region of 30 lichen thalli from two islands: Iceland and Oland. While Sanger recovered just one photobiont genotype from each thallus, the Ion Torrent data recovered 10-18 OTUs for each pool of 5 lichen thalli, suggesting that individual lichens can contain heterogeneous photobiont populations. Both methods showed evidence for photobiont sharing between Thamnolia and Cetraria on Iceland. In contrast, our data suggest that on Oland the two mycobionts associate with distinct photobiont communities, with few shared OTUs revealed by Ion Torrent sequencing. Furthermore, by comparing our sequences with public data, we identified closely related photobionts from geographically distant localities. Taken together, we suggest that the photobiont composition in Thamnolia and Cetraria results from both photobiont-mycobiont codispersal and local acquisition during mycobiont establishment and/or lichen growth. We hypothesize that this is a successful strategy for lichens to be flexible in the use of the most adapted photobiont for the environment.

Abstract: Aim The hypotheses proposed to explain the high percentage of bipolar lichens in Antarctica have never been explicitly tested. We used the strictly bipolar, coastal lichenized fungus Mastodia tessellata (Verrucariaceae, Ascomycota) and its photobionts (Prasiola, Trebouxiophyceae, Chlorophyta) as model species to discern whether this extraordinary disjunction originated from vicariance or long-distance dispersal. Location Coasts of Antarctica, Tierra del Fuego (Chile), Alaska (USA) and British Columbia (Canada). Methods Based on a comprehensive geographical (315 specimens and 16 populations from Antarctica, Tierra del Fuego and North America) and molecular sampling (three and four loci for the fungus and algae respectively), we implemented explicit Bayesian methods to compare alternative hypotheses of speciation and migration, and performed dating analyses for the fungal and algal partner, in order to infer the timing of the colonization events and the direction of gene flow among distant, disjunct areas. Results Mastodia tessellata comprises two fungal species which in turn associate with three photobiont lineages along the studied distribution range. Independent estimation of divergence ages for myco- and photobionts indicated a middle to latest Miocene species split in the Southern Hemisphere, and a late Miocene to Pleistocene acquisition of the bipolar distribution. Comparison of migration models and genetic diversity patterns suggested an austral origin for the bipolar species. Main conclusions The complex evolutionary history of Mastodia tessellata s.l. can be explained by a combination of vicariant and long-distance dispersal mechanisms. We provide novel evidence of a pre-Pleistocene long-term evolution of lichens in Antarctica as well as for bipolar distributions shaped by Southern to Northern Hemisphere migratory routes without the need for stepping stones.

Abstract: The microbial diversity and function of terrestrial lichens have been well studied, but knowledge about the non-photosynthetic bacteria associated with marine lichens is still scarce. 16S rRNA gene Illumina sequencing was used to assess the culture-independent bacterial diversity in the strictly marine cyanolichen species Lichina pygmaea and Lichina confinis, and the maritime chlorolichen species Xanthoria aureola which occupy different areas on the littoral zone. Inland terrestrial cyanolichens from Austria were also analysed as for the marine lichens to examine further the impact of habitat/lichen species on the associated bacterial communities. The L. confinis and L. pygmaea communities were significantly different from those of the maritime Xanthoria aureola lichen found higher up on the littoral zone and these latter communities were more similar to those of the inland terrestrial lichens. The strictly marine lichens were dominated by the Bacteroidetes phylum accounting for 50% of the sequences, whereas Alphaproteobacteria, notably Sphingomonas, dominated the maritime and the inland terrestrial lichens. Bacterial communities associated with the two Lichina species were significantly different sharing only 33 core OTUs, half of which were affiliated to the Bacteroidetes genera Rubricoccus, Tunicatimonas and Lewinella, suggesting an important role of these species in the marine Lichina lichen symbiosis. Marine cyanolichens showed a higher abundance of OTUs likely affiliated to moderately thermophilic and/or radiation resistant bacteria belonging to the Phyla Chloroflexi, Thermi, and the families Rhodothermaceae and Rubrobacteraceae when compared to those of inland terrestrial lichens. This most likely reflects the exposed and highly variable conditions to which they are subjected daily.

Abstract: Lichens exhibit varying degrees of specialization with regard to the surfaces they colonize, ranging from substrate generalists to strict substrate specialists. Though long recognized, the causes and consequences of substrate specialization are poorly known. Using a phylogeny of a 150-200 Mya clade of lichen fungi, we asked whether substrate niche is phylogenetically conserved, which substrates are ancestral, whether specialists arise from generalists or vice versa and how specialization affects speciation/extinction processes. We found strong phylogenetic signal for niche conservatism. Specialists evolved into generalists and back again, but transitions from generalism to specialism were more common than the reverse. Our models suggest that for this group of fungi, 'escape' from specialization for soil, rock and bark occurred, but specialization for wood foreclosed evolution away from that substrate type. In parallel, speciation models showed positive diversification rates for soil and rock dwellers but not other specialists. Patterns in the studied group suggest that fungal substrate specificity is a key determinant of evolutionary trajectory for the entire lichen symbiosis.

Abstract: Malicek, J., Palice, Z., Acton, A., Berger, F., Bouda, F., Sanderson, N. & Vondrak, J. 2018. Uholka primeval forest in the Ukrainian Carpathians — a keynote area for diversity of forest lichens in Europe. — Herzogia 31: 140–171.One of the largest European primeval forests, Uholka-Shyrokyi Luh in the Ukrainian Carpathians, has received increased attention in recent years. In spring 2015 we explored the lichen biota in the southern part of the reserve. Species richness of epiphytic and epixylic lichens presented in this paper far exceeds all numbers achieved in other Central European old-growth forests. In total, 370 lichenized and lichen-allied fungi and 30 lichenicolous fungi were recorded. We focused on forest lichens on organic substrata, inorganic substrata were largely ignored. Species composition in the Uholka forest includes many rare taxa and typical old-growth forest species: e.g. Cetrelia spp., Gyalecta spp., Leptogium saturninum, Lobaria pulmonaria, Ricasolia amplissima, Sclerophora farinacea, S. pallida, Thelopsis flaveola and T. rubella. Opegrapha fumosa, Pyrenula chlorospila and P. dermatodes represent oceanic species that are very rare outside western Europe. Biatora longispora, Calicium montanum, Menegazzia subsimilis, Micarea perparvula, Ochrolechia trochophora, Pyxine sorediata, Ramonia luteola and Thelotrema suecicum are examples of phytogeographically remarkable or generally very rare lichens. Thirty lichenized and ten lichenicolous fungi are new to Ukraine, including Biatora bacidioides and Pertusaria macounii not previously reported from Europe.

Abstract: The common notion that the extensive European Paleogene amber deposits derived from tropical or subtropical forests has recently been questioned on the basis of plant inclusions, which rather suggest temperate forests as source ecosystems. Findings from fossil macrolichens are, likewise, most consistent with humid but relatively well-illuminated temperate forests. Here, we compare the functional morphology of extant calicioid lichens and fungi to those of fossils preserved in European amber. The findings demonstrate that key features in the morphology of these organisms have not changed since at least the Eocene, indicating also that their fundamental niches have remained stable. The prominent presence of calicioids among amber fossils gives strong support to the overall perception of European Paleogene amber forests as temperate forests with variable and in places open canopies. These forests provided calicioids with suitable substrate and a variety of microhabitats that combined favorable light conditions with high atmospheric humidity.