Lichen Abundance Research Articles

Comparing greenhouse and field biocrust cultivation methods in the Sonoran Desert

Abstract Developing methods to use biocrusts in restoration is becoming more important as land use and climate change impact the health and intactness of high‐stress ecosystems. Methods of cultivation to maximize the production of biocrusts for use in restoration activities are necessary because salvage opportunities are limited. Our objective for this research was to determine an optimal method for scalable biocrust cultivation. We tested two Field and one Greenhouse cultivation methods. The Field cultivation methods had a base layer of weed cloth, soil and irrigation with either (1) shade cloth immediately over the surface (Quesadilla method) or (2) with shade cloth over a 1 m tall hoophouse (Hoophouse method). The Greenhouse method had nested basins with water wicking up to the soil surface and biocrust from below, with shade cloth attached to basins. We crossed these methods with the addition of native soil or sand and with and without a base of jute using salvaged biocrusts from the Sonoran Desert. All methods led to at least doubling biocrust cover in 11 weeks. The Greenhouse method led to the highest cover of cyanobacteria and mosses, whereas the field Quesadilla method and the addition of native soil in all cultivation methods led to higher abundance of lichens. There were interactions of cultivation method and soil type, with Greenhouse cultivation and native soil promoting the highest cyanobacteria cover and chlorophyll a. We measured exopolysaccharide sheaths (EPS) in native soil and all cultivation conditions, finding no differences for tightly bound sheath fractions, but higher quantities of the loosely bound EPS in the Greenhouse. We also quantified native and non‐native plants in cultivation, finding few plants in Greenhouse cultivation, but high abundance in both Field methods, and particularly with native soil and without jute for native plants. Practical implication: Together, these results demonstrate that all three cultivation methods are successful for bulking biocrust materials for restoration, and preference should be given to the method that is the easiest and most accessible for practitioners.

Use of lichens as bioindicators of contamination by agrochemicals and metals.

The presence or absence of lichens serves as an indicator of the condition of an ecosystem and the degree to which it is contaminated by various agents, such as agrochemicals and metals. Evaluating the use of lichens as bioindicators of agrochemical contamination could provide a more comprehensive perspective of current contamination levels. Monitoring was conducted over a 4-month period in two study areas: one was a well-conserved area contaminated by metals, and the other was an area surrounded by agricultural crops contaminated by agrochemicals. Data on the presence and abundance of lichens in each study area were recorded at 10 monitoring points, a procedure that was repeated 16 times (every 15days), and concentrations of heavy metals and "organophosphate" agrochemicals in the lichens collected were measured by means of Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-OES) and Gas Chromatography (GC), respectively. Generalized linear mixed models were used to assess abundance and richness, while general linear mixed models were used to attain Shannon diversity and Simpson dominance indices. Moreover, a multivariate analysis was performed in order to compare the lichen communities in both areas. The results indicated differences between the area contaminated by metals and that contaminated by agrochemicals in terms of abundance and Simpson's dominance index, while no differences were found in the case of the richness and diversity models. The PERMANOVA analysis additionally showed differences between the lichen communities in the two areas. The results also demonstrated that Canoparmelia caroliniana bioaccumulated metals in both areas. The levels of barium, cadmium, and sodium were higher in the area contaminated by metals, while concentrations of chromium and copper were higher in the area contaminated by agrochemicals. Finally, the concentrations of agrochemicals were higher in the area contaminated by agrochemicals and included toxic substances such as Methylparathion and Parathion, which are prohibited in Ecuador. In conclusion, this research underscores the importance of lichens as precise indicators of environmental health and contamination by agrochemicals and metals.

Effect of host tree traits on the abundance of epiphytic lichens in a tropical Atlantic rainforest

Effect of host tree traits on the abundance of epiphytic lichens in a tropical Atlantic rainforest

Using the Diversity of Lichens in Maribu Forest Area, West Sentani District, Jayapura Regency as a Baseline Data on Environmental Changes

Lichens are thallophytes, capable of absorbing water, nutrients, and chemical compounds in the air, which led to their application as bio-indicators of air quality. Therefore, this research aimed to determine the abundance and diversity of lichens in the Maribu Village, West Sentani District, Jayapura Regency. This research used the exploration method by tracing the observation paths for vegetation and the presence of lichens. This research established three observation stations with three observation plots of 5 m × 5 m in each station. The obtained samples were identified in the Biology Laboratory of FMIPA Cenderawasih University. This research identified 14 tree species belonging to 12 families and 22 species of lichens belonging to 10 families in the observation plots. Phlyctis argena (39 colonies) and Cryptothecia striata (32 colonies) had the highest colony and fell in the 'very common' category, with the diversity index value (H') of 2.79, which was in the medium category status. The results became the first recorded data in the lowland areas of Papua and could become a baseline for further research.

Can partial-cut harvesting be used to extend the availability of terrestrial forage lichens in late-seral pine-lichen woodlands? Evidence from the Lewes Marsh (southern Yukon) silvicultural systems trial

In northern British Columbia and southern Yukon woodland, caribou forage extensively on terrestrial lichens, predominately mat-forming Cladina species in late-successional pine-lichen woodlands. Many of these stands are now reaching a point in their development where lichen abundance declines as feather-moss mats increase. We evaluated the response of forest floor plant communities in pine-lichen woodlands from the southern Yukon Lewes Marsh partial-cutting trial 8 years after harvesting. Photoplot results documented a major decline (>60% ± 5.6% SE) in the mean surface area of existing large clumps of C. mitis in control (unharvested) treatments, whereas the mean surface area of large C. mitis clumps declined by 28% (±15% SE) in the one-third basal-area removal and showed an increase of 13.5% (±25% SE) in the two-thirds basal-area removal. Line intercept transects documented no changes in overall stand-level lichen abundance between pre-harvest (2012) and post-harvest (2021) measurements, while feather-moss mats and dwarf shrubs showed declines and increases, respectively, in partial-cutting harvest plots. Stand thinning may provide a bridging strategy to extend the period of forage lichen availability in late-seral pine-lichen woodlands, an important consideration in landscapes where increasing severity and frequency of fires are changing the seral-state distribution of caribou habitat.

Mapping lichen abundance in ice-free areas of Larsemann Hills, East Antarctica using remote sensing and lichen spectra

Lichen communities are known to be most resistant and adapted organisms to the extreme environments; however, their abundance is not well mapped. Extensive lichen surveys were conducted as part of the 39th Indian scientific expedition and in-situ spectra (350 nm–2500 nm) of lichens were collected in the Larsemann Hills, East Antarctica during austral summer of 2020. Lichen abundance mapping was carried out with the help of Sentinel-2 MSI L2 data and surveyed records along with in-situ spectra. We generated feature collections for lichen, snow, water, bare surface and trained a random forest (RF) classification algorithms implemented in GEE and generated multi-class outputs. We finally merged all non-lichen classes and produced binary pixels with a confidence value (between 0 and 100) depicting similarity of its spectral response to that of a lichen pixel. Total 92 lichen points, 20 bare rock points, 26 points of water and 74 snow points were used to generate the probabilistic lichen abundance map. Resubstitution accuracy of 97.31% was obtained with 10 number of RF trees. Validation was done with geotagged ground photographs having 232 lichens, 20 bare rocks, 22 water and 69 snow points and achieved test accuracy of 82.44%.

Vertical and altitudinal distribution patterns of hydrophilic saxicolous lichens across French streams

We collected 252 samples in 53 French streams at 3 different heights (low-flow channel, upper limit of streambed, and intermediate zone) across a 190–2200 m altitudinal range, from which we identified and determined the abundance of freshwater lichens to test hypotheses of assemblage zonation. A total of 149 lichenic taxa, including 42 hydrophilic species together with 6 environmental parameters (relative height to stream water, altitude, general and specific orientation, slope, and substratum) were recorded. Hydrophilic species richness was relatively homogenous across height categories and altitudinal classes. Using Canonical Correspondence Analyses, we showed that lichen species, particularly hydrophilic ones, were strongly discriminated along gradients of both exposure to stream water and altitude. Consequently, we proposed a new denomination of freshwater lichens based on their affinity with exposure to stream water: (i) hyperhydrophilic (submersion >9 mo/yr; 14 sp.), (ii) mesohydrophilic (15 sp.), and (iii) subhydrophilic (submersion <3 mo/yr; 15 sp.). We also introduced a 2D typology of freshwater lichens relying on both crossed environmental parameters and showing continuous shifts in species assemblage along gradients.

Effects of root plates, pits and mounds following windthrow events on the biodiversity of plants and lichens in Central European mountain forests

Windthrows lead to the formation of a characteristic land microtopography and they provide new habitats and substrata for species. The present study is novel, because it concerns different taxonomic groups of organisms and effects of various variables on species composition, richness and abundance within root plate-pit-mound (RPM) complexes. For the first time we studied lichens, liverworts, mosses and vascular plants on RPM complexes across major vegetation types, from deciduous to coniferous forests. We analyzed 164 RPM complexes which included in total 268 components: 115 root plates, 80 pits and 73 mounds. Besides the vegetation types and component types the following variables were also considered: dimensions (area, size), age (decomposition degree), species of the uprooted tree, shade, and elevation. The research revealed that root plates, pits and mounds had their own indicator species, but the key factors for the species composition were the species of uprooted trees and the vegetation type. Furthermore, the type of component and the vegetation type were also the most main variables determining the richness and abundance of the studied taxonomic groups of species. Analyses revealed the greatest species richness and abundance of lichens on root plates, and the highest richness of liverworts and vascular plants in pits. The type of component had no effect on the species richness of mosses. However, they were most abundant on mounds. The response of individual groups to the vegetation types and other variables varied. Findings from the study indicated that the presence of uprooted trees with different features (size and age, species of uprooted tree) is important for the biodiversity of mountain forests. We recommend leaving uprooted trees in forest communities for natural colonization, preferably large objects. Moreover, in managed forests a mosaic of forest communities that mimic the structure of natural unmanaged forests should be supported.

The response of lichens inhabiting exposed wood of spruce logs to post-hurricane disturbances in Western Carpathian forests

We investigated which of the following environmental factors: the number of years since the windthrow of the tree (the age of dead wood), the phytocenosis (the type of forest community), altitude, exposure, wood hardness and the spatial scale of forest disturbances (small gaps with a few fallen spruces vs large-area windthrows) contributed to the diversity and abundance of lichens inhabiting the exposed wood of windthrown spruce trees in Polish Western Carpathian forests. Both Shannon H index and sum of coverage coefficients rose with increasing age of the wood, levelling off after 11–14 y (diversity) and 14–17 y (abundance). This factor appeared to be the most important for this group of lichens, but the significant positive impact of large-area windthrows on the lichen abundance was also demonstrated by using a GLM model. The age of the wood we precisely determined on the basis of data on Norway spruce mortality collected annually in permanent plots of the Gorce National Park since 2000. Using the Shore durometer we linked the course of the wood-inhabiting lichen succession with wood decay more precisely than before. The largest number of species was associated with medium hard wood, i.e., 51 < x ≤ 80 on the Shore scale. Based on the NMDS analysis, we distinguished four age groups of logs, differing in lichen abundance and defined by the dominance of distinctive species. A large number of usually corticolous lichen species used the wood of windthrown spruce logs as an optional habitat to survive large-scale, post-hurricane forest disturbances.

Unravelling Novel Phytochemicals and Anticholinesterase Activity in Irish Cladonia portentosa.

Acetylcholinesterase inhibitors remain the mainstay of symptomatic treatment for Alzheimer's disease. The natural world is rich in acetylcholinesterase inhibitory molecules, and research efforts to identify novel leads is ongoing. Cladonia portentosa, commonly known as reindeer lichen, is an abundant lichen species found in Irish Boglands. The methanol extract of Irish C. portentosa was identified as an acetylcholinesterase inhibitory lead using qualitative TLC-bioautography in a screening program. To identify the active components, the extract was deconvoluted using a successive extraction process with hexane, ethyl acetate and methanol to isolate the active fraction. The hexane extract demonstrated the highest inhibitory activity and was selected for further phytochemical investigations. Olivetolic acid, 4-O-methylolivetolcarboxylic acid, perlatolic acid and usnic acid were isolated and characterized using ESI-MS and two-dimensional NMR techniques. LC-MS analysis also determined the presence of the additional usnic acid derivatives, placodiolic and pseudoplacodiolic acids. Assays of the isolated components confirmed that the observed anticholinesterase activity of C. portentosa can be attributed to usnic acid (25% inhibition at 125 µM) and perlatolic acid (20% inhibition at 250 µM), which were both reported inhibitors. This is the first report of isolation of olivetolic and 4-O-methylolivetolcarboxylic acids and the identification of placodiolic and pseudoplacodiolic acids from C. portentosa.

Semi-domesticated reindeer avoid winter habitats with exotic tree species Pinus contorta

The introduction of exotic tree species can have profound effects on the native environment, including habitat use and movement patterns of animals, as well as becoming a management challenge for other land users. Here, we used GPS data from reindeer (Rangifer tarandus) and remote sensing measurements of lichen cover and soil moisture to assess the effects of the exotic lodgepole pine (Pinus contorta) on reindeer husbandry by the Indigenous Sámi in northern Sweden. We used locational data from 67 reindeer for three winters to analyze their habitat selection at the second-order selection (placement of home range in the landscape) and third-order selection (selection of sites within the home range) in relation to land cover class, terricolous lichen cover as measure of winter forage abundance, topographic features, and distance to roads. We also analyzed remotely sensed abundance of lichens in different forest types, and the association between these forest types and soil moisture as measure of suitability as lichen habitat. Compared to native P. sylvestris, we found that reindeer avoided stands with P. contorta where trees were higher than three meters. If P. contorta was the dominant tree species, reindeer were 60 % less likely to select these stands compared to stands with P. sylvestris, and 40 % less likely if P. contorta was less dominant at both orders of selection. We also found that reindeer selected areas with higher lichen cover. Lichen cover was lower in P. contorta stands compared to stands of the native P. sylvestris, even though P. contorta occurred mainly on dry soils usually favorable for terricolous lichens. We conclude that planting P. contorta on soils suitable for terricolous lichens is likely to reduce forage availability for reindeer and turn habitats earlier preferred by reindeer into avoided habitat, resulting in an overall reduction of winter grazing grounds. The effects of stands with P. contorta, albeit covering a comparatively small percentage of the reindeer husbandry area, need to be seen in context with generally declining terricolous lichen abundance due to land uses like forestry and other cumulative effects by external pressures on reindeer husbandry.

Climate change drives substantial decline of understorey species richness and abundance in Norway spruce forests during 32 years of vegetation monitoring

AbstractQuestionsObservations in permanent forest vegetation plots in Norway and elsewhere indicate that complex changes have taken place over the period 1988–2020. These observations are summarised in the “climate‐induced understorey change (CIUC)” hypothesis, i.e. that the understorey vegetation of old‐growth boreal forests in Norway undergoes significant long‐term changes and that these changes are consistent with the ongoing climate change as an important driver. Seven testable predictions were derived from the CIUC hypothesis.LocationNorway.MethodsVegetation has been monitored in a total of 458 permanently marked plots, each 1 m2, in nine old‐growth forest sites dominated by Picea abies at intervals of 5–8 years over the 32‐year study period. For each of the 52 combinations of site and year, we obtained response variables for the abundance of single species, abundance and species density of taxonomic–ecological species groups and two size classes of cryptogams, and site species richness. All of these variables were subjected to linear regression modelling with site and year as predictors.ResultsMean annual temperature, growing‐season length and the number of days with precipitation were higher in the study period than in the preceding ca. 30‐year period, resulting in increasingly favourable conditions for bryophyte growth. Site species richness decreased by 13% over the 32‐year study period. On average, group abundance of vascular plants decreased by 24% (decrease in forbs: 38%). Patterns of group abundance change differed among cryptogam groups: although peat‐moss abundance increased by 39%, the abundance of mosses, hepatics and lichens decreased by 13%, 49% and 67%, respectively. Group abundance of small cryptogams decreased by 61%, whereas a 13% increase was found for large cryptogams. Of 61 single species tested for abundance change, a significant decrease was found for 43 species, whereas a significant increase was found only for 6 species.ConclusionsThe major patterns of change in species richness, group species density and group abundance observed over the 32‐year study period accord with most predictions from the CIUC hypothesis and are interpreted as direct and indirect responses to climate change, partly mediated through changes in the population dynamics of microtine rodents. The more favourable climate for bryophyte growth explains the observed increase for a few large bryophyte species, whereas the decrease observed for small mosses and hepatics is interpreted as an indirect amensalistic effect, brought about by shading and burial in mats of larger species and accelerated by reduced fine‐scale disturbance by microtine rodents. Indirect effects of a thicker moss mat most likely drive the vascular plant decline although long‐term effects of tree‐stand dynamics and former logging cannot be completely ruled out. Our results suggest that the ongoing climate change has extensive, cascading effects on boreal forest ecosystems. The importance of long time‐series of permanent vegetation plots for detecting and understanding the effects of climate change on boreal forests is emphasised.

Increased Light Exposure Decreases Lichen Abundance on Linden Trees in the Prairie Grassland Biome of West Central Minnesota

Increased Light Exposure Decreases Lichen Abundance on Linden Trees in the Prairie Grassland Biome of West Central Minnesota

Frequency, Abundance and Distribution of Lichen In National Botanical Garden, Mirpur, Dhaka, Bangladesh

An investigation was carried out to study lichen flora of National Botanical Garden, Dhaka, during the tenure of May 2018 to April 2019. Seven genera of lichens namely Chrysothrix, Cladonia, Cryptothecia, Herpothallon, Parmelia, Pertusaria and Usnea were recorded from 15 blocks of the Garden. Lichens were abundantly grown and their number increased from June to October, whereas from November to April the number of lichens gradually decreased. The maximum frequency percentage (36.52) of the association found in Parmelia while minimum frequency percentage was recorded 2.48 in Usnea. Among three different heights, the highest number of lichens was recorded within 2 to 4 feet. Most exclusively, Parmelia was found in all the studied blocks, whereas other identified lichens were observed randomly. The present investigation will be helpful to enrich the knowledge on lichen biota of Bangladesh. Dhaka Univ. J. Biol. Sci. 31(2): 273-280, 2022 (July)

Long-term fungus–plant covariation from multi-site sedimentary ancient DNA metabarcoding

Climate change has a major impact on arctic and boreal terrestrial ecosystems as warming leads to northward treeline shifts, inducing consequences for heterotrophic organisms associated with the plant taxa. To unravel ecological dependencies, we address how long-term climatic changes have shaped the co-occurrence of plants and fungi across selected sites in Siberia.We investigated sedimentary ancient DNA from five lakes spanning the last 47,000 years, using the ITS1 marker for fungi and the chloroplast P6 loop marker for vegetation metabarcoding. We obtained 706 unique fungal operational taxonomic units (OTUs) and 243 taxa for the plants. We show higher OTU numbers in dry forest tundra as well as boreal forests compared to wet southern tundra. The most abundant fungal taxa in our dataset are Pseudeurotiaceae, Mortierella, Sordariomyceta, Exophiala, Oidiodendron, Protoventuria, Candida vartiovaarae, Pseudeurotium, Gryganskiella fimbricystis, and Trichosporiella cerebriformis. The overall fungal composition is explained by the plant composition as revealed by redundancy analysis. The fungal functional groups show antagonistic relationships in their climate susceptibility. The advance of woody taxa in response to past warming led to an increase in the abundance of mycorrhizae, lichens, and parasites, while yeast and saprotroph distribution declined. We also show co-occurrences between Salicaceae, Larix, and Alnus and their associated pathogens and detect higher mycorrhizal fungus diversity with the presence of Pinaceae. Under future warming, we can expect feedbacks between fungus composition and plant diversity changes which will affect forest advance, species diversity, and ecosystem stability in arctic regions.

Structural Features of a Post-Clear-Cutting Ecotone between 90-Year-Old Bilberry Spruce Forest and 35-Year-Old Herbs-Forbs Deciduous Stand

In a natural regeneration process, a community dominated by birch and aspen forms in the site 35 years after a bilberry-type spruce stand is logged down. The newly formed ecotone complex consists of four zones, each characterized by certain features of the ground vegetation and epiphytic vegetation structure. The transitional zones and the mature bilberry-type spruce forest feature a clear dominance of boreal dwarf shrubs (bilberry and cowberry). Another feature of the transitional zone is a greater role of hygrophytic mosses of the genera Polytrichum and Sphagnum. Meanwhile, the true mosses Pleurozium schreberi and Hylocomium splendens dominate under spruce forest canopy, and the moss cover in the young deciduous stand is virtually nonexistent. The structure of epiphytic vegetation depends on the habitat conditions—the surface of tree trunks in the transitional zone is better lit and drier than inside the tree stand, which results in a higher abundance of epiphytic lichens of the genus Cladonia. The deciduous–coniferous fine root biomass ratio is dependent on the tree stand structure and is unrelated to ecotone zones. Overall, studies have demonstrated that transitional zones have certain characteristic ecological and community features, which persist for a long time after tree stand removal.

An artificial intelligence approach to remotely assess pale lichen biomass

Although generally given little attention in vegetation studies, ground-dwelling (terricolous) lichens are major contributors to overall carbon and nitrogen cycling, albedo, biodiversity and biomass in many high-latitude ecosystems. Changes in biomass of mat-forming pale lichens have the potential to affect vegetation, fauna, climate and human activities including reindeer husbandry. Lichens have a complex spectral signature and terricolous lichens have limited growth height, often growing in mixtures with taller vegetation. This has, so far, prevented the development of remote sensing techniques to accurately assess lichen biomass, which would be a powerful tool in ecosystem and ecological research and rangeland management. We present a Landsat based remote sensing model developed using deep neural networks, trained with 8914 field records of lichen volume collected for >20 years. In contrast to earlier proposed machine learning and regression methods for lichens, our model exploited the ability of neural networks to handle mixed spatial resolution input. We trained candidate models using input of 1 × 1 (30 × 30 m) and 3 × 3 Landsat pixels based on 7 reflective bands and 3 indices, combined with a 10 m spatial resolution digital elevation model. We normalised elevation data locally for each plot to remove the region-specific variation, while maintaining informative local variation in topography. The final model predicted lichen volume in an evaluation set (n = 159) reaching an R2 of 0.57. NDVI and elevation were the most important predictors, followed by the green band. Even with moderate tree cover density, the model was efficient, offering a considerable improvement compared to earlier methods based on specific reflectance. The model was in principle trained on data from Scandinavia, but when applied to sites in North America and Russia, the predictions of the model corresponded well with our visual interpretations of lichen abundance. We also accurately quantified a recent historic (35 years) change in lichen abundance in northern Norway. This new method enables further spatial and temporal studies of variation and changes in lichen biomass related to multiple research questions as well as rangeland management and economic and cultural ecosystem services. Combined with information on changes in drivers such as climate, land use and management, and air pollution, our model can be used to provide accurate estimates of ecosystem changes and to improve vegetation-climate models by including pale lichens.

Habitat Fragmentation and Lichen Diversity in Peri-Urban Woodlands: A Case Study in the Municipality of Potenza (Southern Italy).

The fragmentation of the natural habitat is a process that is exponentially increasing worldwide and represents one of the biggest threats to biological diversity. Habitat destruction and fragmentation have a major impact on landscapes and may also affect ecosystems, populations, and species. The ongoing anthropogenic process can result in habitat loss for some species, habitat creation for others, reduced patch size, and increased distance between patches, which may lead to local extinction. We analyzed the effects of patch size and isolation on lichens in Quercus pubescens woods surrounding the city of Potenza (south Italy). We randomly sampled 11 forest patches with homogeneous environmental variables using circular plots with a 10 m radius; the patches ranged from 0.3 to 30 ha. For each plot, we collected data about presence and abundance of epiphytic lichens. We performed the analyses at the patch level using linear regression and multivariate analysis, searching for effects on species richness, life forms, and community compositions. Multivariate analyses were used to study the effect of fragmentation on the structure of lichen vegetation. We investigated the main predictor of lichen species richness in habitat fragmentations and concluded that patch area per se is an important (positive) driver of lichen species richness in Mediterranean peri-urban forests.

Stand openness predicts hair lichen (Bryoria) abundance in the lower canopy, with implications for the conservation of Canada’s critically imperiled Deep-Snow Mountain Caribou (Rangifer tarandus caribou)

Tree-dwelling hair lichens in the genus Bryoria provide crucial late-winter forage for Deep-Snow Mountain Caribou (DSC), an imperiled ungulate endemic to south-central British Columbia, Canada. Because DSC survival requires continuous access to heavy hair lichen loadings, conservation efforts can benefit from an improved understanding of the factors that contribute to such loadings. Here we quantify the relation of Bryoria abundance to stand spacing by testing an “Angle-To-Canopy-Skyline” (ATCS) protocol as a measure of stand openness and a proxy for ventilation. Fieldwork conducted in 60-year-old conifer forests on a 250-m conical volcano within the range of DSC yielded three principal findings: (1) Bryoria abundance strongly increases with increasing stand openness; (2) Pinus contorta supports much heavier Bryoria loadings than other local host trees; and (3) ATCS is a powerful predictor of arboreal hair lichen abundance in general across a wide range of environmental settings, but does not predict the abundance of foliose lichens. We suggest that canopy openness, at least within the range of DSC, complements stand age as a key factor in the development of heavy Bryoria loadings, consistent with the hypothesis that Bryoria benefits from rapid drying after rain. The possibility that anomalously high Bryoria abundance on Pinus may hold promise for accelerated DSC habitat restoration following clearcut logging is explored but rejected.

What determines the diversity and succession of lichens inhabiting post-bark beetle snags in the Western Carpathians?

The life strategy of Norway spruce allows the recovery of European spruce forests in a scenario of catastrophic disturbances caused by the European spruce bark beetle. However, little is known about how the development of this insect infestation has influenced the preservation of the ecological balance in these forests over the last decades. Based on the upper montane spruce forests in the Polish Western Carpathians, we decided to check what species of lichens are using the decaying wood of post-bark beetle snags and how the progressive changes in wood hardness and stand decomposition affect the process of species exchange. In 2018–2019, we investigated spruce snags on permanent monitoring plots in Gorce National Park, whose cause and time of death have been recorded since 1999, and earlier in 1992 and 1997. The study covered 374 post-bark beetle spruce snags at 76 sites. We found 84 species, including 77 lichens, 6 lichenicolous fungi and one non-lichenised fungus, 15 of which were exclusively wood-inhabiting species in Gorce range. Using generalised linear models, the wood age (A) and the scale of the forest stand breakdown phenomenon (B) were compared with the altitude (C), the aspects of hillside exposure (D) and the forest plant community (E) in the assessment of their effect on lichen species diversity and abundance. "A” was the most important of the tested factors, significantly and positively influencing both parameters, while “B–D” only weakly influenced lichen abundance. Five groups of wood age, significantly different in the lichen abundance and the composition of species were distinguished, and a characteristic combination of dominant species was determined for each of them. Based on the measurements of the wood hardness under the thalli using Shore’s method, the succession of species during the colonisation of the post-bark beetle snags was determined and four groups of species were selected, most frequent in the successive stages of wood decay process. The wood of spruces killed by the bark beetle is both an important substrate enabling the survival of obligately wood-inhabiting lichen species, as well as providing a habitat supporting the maintenance of epiphytes in the Carpathian forests. This study extends the knowledge about the specific requirements of lichens inhabiting spruce snags, as well as the pace and course of lichen succession on this substrate.