Anthropogenic disturbances can have strong impacts on lichen communities, as well as on individual species of lichenized fungi. Traditionally, lichen monitoring studies are based on the presence and ...abundance of fungal morphospecies. However, the photobionts, as well photobiont mycobiont interactions also contribute to the structure, composition, and resilience of lichen communities. Here we assess the genetic diversity and interaction patterns of algal and fungal partners in lichen communities along an anthropogenic disturbance gradient in Białowieża Forest (Poland). We sampled a total of 224 lichen thalli in a protected, a managed, and a disturbed area of the forest, and sequenced internal transcribed spacer (ITS) ribosomal DNA (rDNA) of both, fungal and algal partners. Sequence clustering using a 97% similarity threshold resulted in 46 fungal and 23 green algal operational taxonomic units (OTUs). Most of the recovered photobiont OTUs (14 out of 23) had no similar hit in the NCBI-BLAST search, suggesting that even in well studied regions, such as central Europe, a lot of photobiont diversity is yet undiscovered. If a mycobiont was present at more than one site, it was typically associated with the same photobiont OTU(s). Generalist species, i.e., taxa that associate with multiple symbiont partners, occurred in all three disturbance regimes, suggesting that such taxa have few limitations in colonizing or persisting in disturbed areas.
associated with 53% of the fungal OTUs, and was generally the most common photobiont OTU in all areas, implying that lichens that associate with this symbiont are not limited by the availability of compatible photobionts in Central European forests, regardless of land use intensity.
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•Niche partitioning and habitat filtering shaped functional diversity of lichens.•Deciduous forests hosted higher functional diversity of lichens than coniferous.•Oak, ash, and dead ...wood promoted high functional diversity of lichens.•Preserving diverse forests providing many niches is important for biodiversity.•Results on lichen functional diversity can be translated to other lowland forests.
Functional diversity is considered an important tool for the identification of ecological mechanisms shaping the coexistence patterns of species communities along different environmental gradients. However, there is a huge gap in knowledge regarding the importance of ecological mechanisms in shaping the composition of lichen communities. We analyzed the functional diversity patterns of the lichen species in a European lowland primeval forest ecosystem, taking into consideration levels of forest communities, phorophyte species and substrates. The greatest functional diversity of lichens at the community level (functional richness and functional dispersion) was found in mixed deciduous forests, where Fraxinus excelsior and Carpinus betulus revealed the highest values of functional dispersion. The most functionally diverse lichen communities were found on the bark of trees, the branches of trees, and the bark on trunks or branches of fallen trees. The lowest functional diversity was found in coniferous forests, evidenced by the low functional dispersion of lichen assemblages, indicating lower heterogeneity of possible niches and harsher environmental conditions comparing with deciduous forests. In coniferous forests, lichens produced small ascomata and ascospores, while in deciduous forests, ascomata and spores of lichens were larger. We concluded that two contrasting mechanisms shaped the functional diversity of lichens in the primeval forest ecosystem: (i) niche-partitioning in deciduous forests, and (ii) environmental filtering in coniferous forests. Our study has substantially broadened and enhanced the existing knowledge concerning the assembly rules of lichen communities and can be considered as a model for the distribution of lichen functional traits in the natural lowland forests of Europe. This approach may also be used to model future changes taking place in this type of ecosystem. Our results are particularly important for forest managers responsible for protection, as they highlight the fundamental importance of certain tree species and specific forest substrates for maintaining high lichen functional diversity. Focus on the protection of all features of diverse forest structures and of diverse forests providing high variety of niches is essential for the successful conservation of forest lichen biota.
The landscape-scale extinction of a tree species may have a negative impact on diversity of associated epiphytic species. We used ordination and hierarchical clustering methods to assess landscape ...and the community level effects of reduction in the abundance of European ash
Fraxinus excelsior
, caused by ash dieback, on the associated epiphytic lichen biota in Białowieża Forest (Poland)—the best preserved forest complex in Central Europe. At the landscape level ash decline impact on the biota of ash-associated epiphytic lichens was weak, due to the high diversity of tree species, which may serve as potential alternative hosts. At this level, oak and hornbeam are the most important alternative hosts, assuring the maintenance of ash-associated epiphytic lichens. Lime, alder, and hazel appeared to be less important but still may serve as substitute phorophytes to approximately 2/3 of the ash-associated lichen biota. About 90% of epiphytic biota are likely to survive on the landscape scale. However, at the community level of alder-ash floodplain forest, where ash was dominant, about 50% of ash-associated epiphytic lichen species are threatened by ash dieback. Our results highlight the importance of a spatial scale in conservation biology. Protection of large forest areas with rich diversity of phorophyte trees increases chances of survival of the associated epiphytic organisms.
Epiphytic lichens are sensitive bioindicators responding to climate change and atmospheric pollutants. Climate warming changes in lichen biota have been reported from Western and Central Europe; ...therefore, similar trends in the biota of the close-to-natural forests of Eastern Europe were expected. In both examinations (1987–1989 and 2015–2016) of 144 permanent plots the same field method was used. The following functional epiphyte groups were distinguished: climate warming indicators (VDI species and species containing Trentepohlia algae) and Wirth's ecological indicators (T – temperature, N – eutrophication, R – reaction, M – moisture). PCA ordination for exploring species composition changes, species richness and diversity (Shannon-Wiener index) in different forest types was used. When compared with the earlier survey, a higher plot species richness, Shannon-Wiener diversity index, and proportion of more nitrogen-demanding lichens, and lower proportions of warm-demanding and high-acidity tolerant lichens were found. No change in the epiphyte biota composition influenced by the decreasing atmospheric precipitation was detected. The species richness and Shannon-Wiener index of climate warming indicators did not show a significant change. Although the share and frequency of epiphytic lichen species and their functional groups changed over a 25-year period, no relationship was found to be related to climate warming: indicators of global warming showed no significant change in frequency, while those with higher value of T even decreased frequency. The changes suggest a connection with eutrophication (increase in frequency of species with higher value of N) and a decrease in sulphur deposition (increase in frequency of species with higher value of R).
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•We studied the effect of climate change and pollutants on epiphytic lichens.•We resampled lichen biota on permanent plots 25 years after original survey.•We found higher share of nitrogen-demanding lichens, but lower of warm-demanding and high-acidity tolerant lichens.•The environment of Białowieża Forest reduces impact of global warming on lichens.•Anthropogenic factors are driving change in lichen biota of natural forest ecosystems.
Phylogenetic analyses using mtSSU and nuITS sequences of Buellia violaceofusca (previously placed in Lecanoromycetes), a sterile, sorediate lichen having a trebouxioid photobiont, surprisingly prove ...that the species is conspecific with Lecanographa amylacea (Arthoniomycetes), a fertile, esorediate species with a trentepohlioid photobiont. These results suggest that L. amylacea and B. violaceofusca are photomorphs of the same mycobiont species, which, depending on the photobiont type, changes the morphology and the reproduction strategy. This is the first example of a lichenized fungus that can select between Trebouxia (Trebouxiophyceae) and trentepohlioid (Ulvophyceae) photobionts. Trebouxia photobionts from the sorediate morphotype belong to at least three different phylogenetic clades, and the results suggest that Lecanographa amylacea can capture the photobiont of other lichens such as Chrysothrix candelaris to form the sorediate morphotype. Phylogenetic analyses based on rbcL DNA data suggest that the trentepohlioid photobiont of L. amylacea is closely related to Trentepohlia isolated from fruticose lichens. The flexibility in the photobiont choice enables L. amylacea to use a larger range of tree hosts. This strategy helps the lichen to withstand changes of environmental conditions, to widen its distribution range and to increase its population size, which is particularly important for the survival of this rare species.
Research highlights: shifts in the composition and functional diversity of lichen biota reflect changes in the environment caused by climate warming and eutrophication. Background and objectives: ...studies on lichen functional diversity and refinement in the functional traits of lichen biota under the pressure of changing environmental factors are currently of great scientific interest. The obtained results are interpreted in relation to specific habitat properties and their modifications due to the potential effects of climate change and atmospheric pollution. The aim of the work was to investigate changes in lichen species composition and functional diversity, as well as to identify factors responsible for them at different forest ecosystem scales. Materials and Methods: we identified factors responsible for changes in lichen biota in a unique Białowieża Forest ecosystem by analyzing shifts in species optima and functional diversity at the forest community, tree phorophyte, and substrate levels. We examined individual lichen species’ responses and temporal shifts in the species composition for each historical and resampled dataset using a community-weighted means of functional lichen traits and Wirth ecological indicator values. Results: the most evident change took place at the level of individual species, which shifted their realized optima: 25 species demonstrated a shift to co-occur with lichens of higher nitrogen demands, 15 demonstrated higher light demands, 14 demonstrated higher temperature preferences, and six demonstrated lower moisture preferences. At the level of forest communities, biota shifted towards the higher proportion of nitrogen-demanding and the lower proportion of moisture-demanding species. At the level of phorophyte species, biota changed towards an increased proportion of lichens of higher temperature preferences. For the substrate level, no directional shifts in lichen species composition were found. Conclusions: climate change has influenced lichen biota in Białowieża Forest, but the main driver of lichen species composition was found to be eutrophication. We suppose that other overlapping factors may contribute to biota shifts, e.g., the extinction and expansion of phorophyte tree species.
Current trends emphasize the importance of the examination of the functional composition of lichens, which may provide information on the species realized niche diversity and community assembly ...processes, thus enabling one to understand the specific adaptations of lichens and their interaction with the environment. We analyzed the distribution and specialization of diverse morphological, anatomical and chemical (lichen secondary metabolites) traits in lichen communities in a close-to-natural forest of lowland Europe. We considered these traits in relation to three levels of forest ecosystem organization: forest communities, phorophyte species and substrates, in order to recognize the specialization of functional traits to different levels of the forest complexity. Traits related to the sexual reproduction of mycobionts (i.e., ascomata types: lecanoroid apothecia, lecideoid apothecia, arthonioid apothecia, lirellate apothecia, stalked apothecia and perithecia) and asexual reproduction of mycobionts (pycnidia, hyphophores and sporodochia) demonstrated the highest specialization to type of substrate, tree species and forest community. Thallus type (foliose, fruticose, crustose and leprose thalli), ascospore dark pigmentation and asexual reproduction by lichenized diaspores (soredia and isidia) revealed the lowest specialization to tree species and substrate, as well as to forest community. Results indicate that lichen functional trait assemblage distribution should not only be considered at the level of differences in the internal structure of the analyzed forest communities (e.g., higher number of diverse substrates or tree species) but also studied in relation to specific habitat conditions (insolation, moisture, temperature, eutrophication) that are characteristic of a particular forest community. Our work contributes to the understanding of the role of the forest structure in shaping lichen functional trait composition, as well as enhancing our knowledge on community assembly rules of lichen species.
Protected areas worldwide are important to maintaining biodiversity and providing recreational opportunities to society. However, many protected areas are affected by unprecedented, large and severe ...natural disturbances, like bark beetle outbreaks. Due to the contrasting responses of different taxonomic groups to disturbance events and largely negative human perceptions of disturbed landscapes, there are conflicting opinions about the appropriate way of managing affected stands. Aligning these different objectives and understanding the responses of biodiversity and visitors' perceptions to different disturbance severities is a prerequisite for disturbance management in protected areas. We conducted multi-taxon biodiversity surveys – including meta-barcoding hyperdiverse groups such as insects and fungi – and analysed the restorativeness (i.e. the landscape's ability to renew personal cognitive capacities for forest visitors) using visitor surveys in five national parks throughout Europe. Response curves of biodiversity and restorativeness were analysed along a continuous gradient of bark beetle infestation severities in Norway spruce forests on the same study plots. Arthropod biomass and the diversity of primary producers and pollinators increased linearly with increasing disturbance severity, while overall multi-diversity (an index of the average scaled species richness per taxonomic group) did not change. Restorativeness decreased linearly with increasing disturbance severity; however, even heavily disturbed forests still had high restorativeness. In spite of the ongoing debates about disturbance management, the high biodiversity and restorativeness that accompany disturbance suggest that major goals of protected areas are not threatened by bark beetle disturbances.
•Arthropod biomass increases along a disturbance severity gradient.•Arthropod OTU richness does not respond to increasing disturbance severity.•Multi-diversity-index is stable along a disturbance severity gradient.•Primary producer and pollinator richness increases with disturbance severity.•Severely disturbed forests have still high restorativeness values.
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