The first epiphytic macrolichen and its implication to the interacting with Mesozoic forest ecosystem

Lichens are well known as pioneer organisms or stress-tolerant extremophiles playing a core role in the early formation of terrestrial ecosystems, of which epiphytic lichens make a distinct contribution to the water-cycle and nutrient cycling in forest ecosystem. But due to the scarcity of relevant fossil records, the evolutionary history of epiphytic lichens is poorly documented. Herein, based on the new material of Daohugouthallus ciliiferus, we demonstrated that the hitherto oldest macrolichen inhabited a gymnosperm branch, representing the first unambiguous Jurassic epiphytic lichen. Combing the fossil and extant macrolichen representatives, we performed the geometric morphometric analysis and comprehensive comparison to infer the systematic status of this rare Jurassic macrolichen. The results declared that D. ciliiferus cannot be assigned to any known macrolichen lineages for its elder age and particular habits, and therefore a new family, Daohugouthallaceae was proposed. This work updated the current knowledge to the historical evolution of epiphytic lichens, implying the macrolichens may have diversified much earlier than the generally accepted K–Pg boundary. In addition, our new finding also provided direct evidence for tracing the continuing joint development of epiphytic lichens and forest ecosystem since the Jurassic of 165 Mya.

Epiphytic lichens of woodland habitats in the lower Ticino river valley and in the “Bosco Siro Negri” Integral Nature State Reserve (NW Italy)

Epiphytic lichens were surveyed in the “Bosco Siro Negri” Integral Nature State Reserve (province of Pavia, Lombardy, NW Italy), which hosts a well-preserved fragment of oak-elm floodplain forest (Natura 2000 Habitat 91F0). The core woodland fragment hosted only four species on the tree boles, i.e. Lepraria finkii plus the forest specialists Coenogonium pineti, Diarthonis spadicea, and Opegrapha vermicellifera. An additional eight nitro- and photophytic species were recorded on the highest twigs of the canopy. The whole Reserve, including the neighbouring degraded woodlands and poplar plantations, hosted 27 epiphytic lichen taxa. The lower Ticino River valley between Vigevano and Pavia, in which the Reserve is located, was surveyed for epiphytic lichens in an additional 45 sites, including 15 wellpreserved oak-elm/hornbeam woodlands (Habitat 91F0), 15 degraded broadleaved woodlands with high occurrence of black locust and 15 poplar plantations. Overall, 32 species were recorded. Well-preserved woodlands had a lower species richness, but they hosted forest specialists not occurring in the other two habitats. Graphis pulverulenta and Lecania cyrtellina are new to Lombardy. Anisomeridium polypori, Diarthonis spadicea, Lecanora expallens and Pseudoschismatomma rufescens are reported from Lombardy for the second time.

Tree species identity and composition shape the epiphytic lichen community of structurally simple boreal forests over vast areas

Greatly simplified ecosystems are often neglected for biodiversity studies. However, these simplified systems dominate in many regions of the world, and a lack of understanding of what shapes species occurrence in these systems can have consequences for biodiversity and ecosystem services at a massive scale. In Fennoscandia, ~90% of the boreal forest (~21Mha) is structurally simplified with little knowledge of how forest structural elements shape the occurrence and diversity of for example epiphytic lichens in these managed forests. One form of structural simplification is the reduction of the number and frequency of different tree species. As many lichen species have host tree preferences, it is particularly likely that this simplification has a huge effect on the lichen community in managed forests. In a 40–70 years old boreal forest in Sweden, we therefore related the occurrence and richness of all observed epiphytic lichens to the host tree species and beta and gamma lichen diversity at the forest stand level to the stand’s tree species composition and stem diameter. Picea abies hosted the highest lichen richness followed by Pinus sylvestris, Quercus robur, Alnus glutinosa, Betula spp., and Populus tremula. However, P. tremula hosted twice as many uncommon species as any of the other tree species. Stand level beta and gamma diversity was twice as high on stands with four compared to one tree species, and was highest when either coniferous or deciduous trees made up 40–50% of the trees. The stem diameter was positively related to lichen richness at the tree and stand level, but negatively to beta diversity. For biodiversity, these findings imply that leaving a few trees of a different species during forest thinning is unlikely as effective as combining life-boat trees for endangered species with an even tree species mixture.

Epiphytic lichen cover of collection trees of arboretum of the Botanical Garden of Petrozavodsk State University

At present, 264 species of lichens and allied fungi have been recorded for the territory of the BotanicalGarden of Petrozavodsk State University (Republic of Karelia) and 112 species have been found in its arboretum, wheremore than 200 species of introduced trees grow. The paper presents the results of studying the features of the epiphyticlichen cover of the collection trees of the arboretum of the Botanical Garden of PetrSU (Republic of Karelia). Results of thestudy are based on 1662 descriptions of the epiphytic lichen cover on 209 trees of coniferous species and 1150 descriptions –on 143 deciduous introduced species.The average total projective cover of lichens on the trunks of the studied coniferous introduced species reaches 18 % atthe trunk base, and 19 % – at a height of 130 cm above the ground. The number of species in the descriptions of epiphyticlichen cover varies from 0 to 12 (0.8 in average). The highest values of the projective cover of lichens and the numberof species in the descriptions were observed on the trunks of conifers of the genus Pinus, the lowest – on the trunks oftrees of the genus Thuja. The average total projective cover of lichens on the trunks of the studied deciduous introducedspecies was 8 % at the base, and 25 % – at a height of 130 cm above the ground. The number of species in the descriptionvaries from 0 to 9 (1.0 in average). The highest values of the projective cover of lichens and the number of species in thedescription are noted on the trunks of the genus Quercus, the lowest – on the trunks of trees of the genus Ulmus. Collectiontrees of arboretum tree represent a model object for observing the features of the formation of the epiphytic lichen cover

Metabolite Profiling of the Indian Food Spice Lichen, Pseudevernia furfuracea Combined With Optimised Extraction Methodology to Obtain Bioactive Phenolic Compounds

Pseudevernia furfuracea (L.) Zopf (Parmeliaceae) is a well-known epiphytic lichen commonly used in Indian spice mixtures and food preparations such as curries. This study is an attempt to find the best extraction methodology with respect to extractive yield, total polyphenolic content (TPC), total flavonoid content and antioxidant activities of lichen P. furfuracea. Two phenolic compounds, atraric acid and olivetoric acid were isolated and quantified in their respective extracts with the aid of reverse phase high performance liquid chromatography (RP-HPLC). The highest concentration of both the compounds, atraric acid (4.89 mg/g DW) and olivetoric acid (11.46 mg/g DW) were found in 70% methanol extract. A direct correlation was also observed between the concentrations of these compounds with the free radical scavenging potential of the extracts which might contribute towards the antioxidant potential of the extract. Moreover, scanning electron microscopy and HPLC analysis which was used to study the effect of pre-processing on extraction process highlighted the capacity of a mixer grinder technique for improved separation of surface localized metabolites and enrichment of the fraction. An investigation of the chemical profile of the bioactive extract 70% methanol extract using UHPLC-DAD-MS lead to tentative identification of forty nine compounds. This extract was also assessed towards HEK 293 T cell line for cytotoxicity analysis. Concentration range of 0.156 to 100 µg/ml of PF70M extract exhibited no significant cell death as compared to control. Further, the active extract showed protective effect against hydroxyl radical’s destructive effects on DNA when assessed using DNA nicking assay. Based upon this, it can be concluded that optimization of extraction solvent, sample pre-proceesing and extraction techniques can be useful in extraction of specific antioxidant metabolites.

Weak recovery of epiphytic lichen communities in Sweden over 20 years of rapid air pollution decline

Epiphytic lichens are sensitive to deteriorating air quality, but levels of nitrogen and especially sulphur deposition have been in decline over most of Europe in recent decades. We assessed the response of epiphytic lichens to this decline, using data from long-term monitoring sites in Sweden. We analyzed 20 years of data to investigate temporal trends in lichen communities’ sensitivity to sulphur, nitrogen preference, species richness and alpha and beta diversity. We found only limited and partial evidence of recovery in the area that previously had high levels of deposition, and a decline in mean sulphur sensitivity at a northern site with low deposition levels throughout the monitoring period. The slow recolonization of sensitive species, even where environmental conditions are now suitable, is probably a result of impoverished regional species pools and the inherent limited dispersal capacity of many lichen species. We suggest due consideration of these factors in the use of epiphytic lichens as environmental indicators in a period of improving air quality.

Modeling heavy metal release in the epiphytic lichen Evernia prunastri

In this study, the release of Cu2+ and Zn2+ was investigated and modeled in the epiphytic lichen Evernia prunastri. Samples were incubated with solutions containing these metals at ecologically relevant concentrations (10 and 100 μM) and then transplanted to a remote area and retrieved after 1, 2, 3, 6, 12, and 18 months. The results showed that, after 12 months, all samples faced similar metal reductions of ca. 80–85%, but after this period, all the involved processes seem to be no longer capable of generating further reductions. These results suggest that the lichen E. prunastri can provide information about environmental improvements after exposure to high or very high pollution levels in a relatively short period of time.

Lack of congruence between terrestrial and epiphytic lichen strata in boreal forests

Lichens occupy diverse substrates across tremendous ranges of environmental variation. In boreal forests, lichen communities co-occur in ‘strata’ defined by terrestrial or arboreal substrates, but these strata may or may not be interchangeable as bioindicators. Do co-occurring lichen strata have similar community structures and environmental responses? Could one stratum serve as a proxy for the other? We assessed variation in species richness and community compositions between ground-layer versus epiphyte-layer lichen strata in boreal forests and peatlands of interior Alaska. Species richness was lower and more spatially structured in the ground layer than the epiphyte layer. Richness of strata was not correlated. The most compositionally unique ground-layer communities were species-poor but contained regionally rare species not common in other plots. Variation in community compositions (ordination scores) were not congruent between strata (Procrustes congruence < 0.16 on 0–1 scale); the largest departures from congruence occurred where ground layers were species-poor. The best predictors of ground-layer community compositions were hydrological and topographic, whereas epiphytes were most associated with macroclimate and tree abundances. We conclude that lichens on different substrates ‘move in different circles’: compositional gradients did not agree and the environmental gradients most important to each lichen stratum were not the same. The conditions which strongly influence one vegetation stratum may have little bearing upon another. As global changes modify habitats, an incremental change in environment may lead community trajectories to diverge among lichen strata.

The value of alien roadside trees for epiphytic lichen species along an urban pollution gradient

Alien tree species have been introduced to Europe and often used as roadside trees. Currently, preference is given to species that are adapted to urban climate and drier conditions. Native epiphytic lichens are adapted to local tree species; however, little is known whether a shift toward more alien roadside trees would affect the diversity of epiphytic lichens within cities. We considered three genera of roadside trees that are common in Hamburg (Germany) Acer, Tilia, and Quercus, each with a native and an alien species per genus. Species numbers, frequency and diversity of epiphytic lichens were assessed and compared. Tree locations were grouped according to three classes of increasing traffic volume as a proxy for air pollution. Mean bark pH values have been recorded for each tree individual. The species pairs Quercus robur/rubra and Acer platanoides/saccharinum showed significant differences in the diversity and abundance of lichens, with the alien species showing lower values. The species pair Tilia cordata/tomentosa did not show any significant differences. The number of nitrogen-tolerant lichen species differed little among all tree species. Lichen species richness decreased with increasing traffic volume for all tree species pairs, thus demonstrating the inhibiting effect of traffic on the occurrence of lichens. Bark pH differed little between the species pairs yet high traffic volume resulted in an increased bark pH. In conclusion, two out of three alien species had negative effects on lichen diversity. Further tree species should be assessed to better estimate the effect of alien roadside trees on lichen diversity.