Search Results (7)

Western Tianshan National Nature Reserve in Xinjiang, China stands out for its uniqueness and high biodiversity, including lichens. This study aims to characterize lichen diversity and compare distribution patterns of different life forms, substratum affinities and photobiont types. Surveys were conducted from June to August 2024 using stratified sampling methods at elevation ranging from 1100 m to 3400 m in the study area. Morphological, anatomical and chemical studies revealed 173 lichen species from 24 families and 58 genera, of which 100 species were identified as crustose, 46 as foliose and 27 as fruticose. Among the different habitat groups, strictly saxicolous lichens were dominant with 89 species, followed by corticolous lichens with 44 species and terricolous lichens with 40 species. The total species richness of lichens has a bimodal pattern: one peak appears at a low altitude (1701–2000 m) and the other at a high altitude (2901–3200 m). Among the three substratum categories studied, the species richness of terricolous lichens showed a unimodal relationship with elevation, and the saxicolous lichen had a bimodal pattern. The species richness of corticolous lichens was highest at lower and medium elevations and decreased at higher elevations. With respect to photobiont type, the species richness of cyanolichens showed a unimodal relationship with elevation. Maximum richness occurred at 2700 m, contrary to the chlorolichens, which had a bimodal pattern. Species richness of all three growth forms of lichens showed a bimodal pattern related to elevation. Among the three morphological types, crustose and foliose species richness had their highest values of 38 and 19, respectively, at 1701–2000 m, and fruticose lichens peaked with a maximum of 13 species at 2301–2600 m. The species richness of crustose lichens is lowest between altitudes 2300 and 2600 m, while the lowest species richness of fruticose and foliose lichens occurs at 2001–2300 m and elevations above 2900 m. Full article

Lobaria pulmonaria (L.) Hoffm. is a tripartite, broad-lobed foliose lichen usually found on bark and on epiphytic and epilithic mosses in humid forests. Currently, the species is threatened in most European countries because of its sensitivity to environmental alterations. In this paper, a total of 107 previous studies across more than 50 years were analysed to gain insight into the multiple roles that L. pulmonaria plays in forest habitats, specifically relating to ecosystem services and as environmental bioindicator. Content analysis was employed to systematically characterise and classify the existing papers on the functions performed by L. pulmonaria into several groups mostly based on research topic and scope. Two main types of ecosystem services (N₂ fixation and feeding) offered by L. pulmonaria have been identified, with varying research aims and types of parameters measured in the studies. Two aspects of current biomonitoring applications using L. pulmonaria in forest habitats (concerning atmospheric pollution and forest management) were analysed, and it was found that the number of related studies increased significantly in recent years. Finally, the current practices of monitoring using L. pulmonaria as a biological indicator are discussed, and recommendations are provided. Full article

The ecological success of lichens is related to both myco- and photobionts which condition the physiological limits of the lichen symbioses and thus affect their ecological niches and geographic ranges. A particular type of lichen, called cephalolichen, is characterized by housing both green algal and cyanobacterial symbionts—the latter is restricted to special structures called cephalodia. In this type of lichen, questions related to specialization within species or within individuals are still unsolved as different patterns have previously been observed. In order to study the variability at the intrathalline, intraspecific, and interspecific level, cyanobionts from different cephalodia within the same thalli and from different thalli were genetically analysed in three cephalolichen species at two different forests (18 thalli, 90 cephalodia). The results showed variability in the cephalodial Nostoc OTUs in all the studied species, both at the intrathalline and intraspecific levels. The variability of Nostoc OTUs found in different cephalodia of the same thallus suggests low specialization in this relationship. Additionally, differences in OTU diversity in the three studied species and in the two forests were found. The variability observed may confer an increased ecological plasticity and an advantage to colonize or persist under additional or novel habitats or conditions. Full article

Volatile compounds from the marine cyanolichen Lichina pygmaea, collected from the Moroccan Atlantic coast, were extracted by hydrodistillation and their putative chemical composition was investigated by gas chromatography coupled to mass spectrometry (GC/MS). Based on the obtained results, Lichina pygmaea volatile compounds (LPVCs) were mainly dominated by sesquiterpenes compounds, where γ-himachalene, β-himachalene, (2E,4E)-2,4 decadienal and α-himachalene were assumed to be the most abundant constituents, with percentage of 37.51%, 11.71%, 8.59% and 7.62%, respectively. LPVCs depicted significant antimicrobial activity against all tested strains (Staphylococcus aureus CCMM B3, Pseudomonas aeruginosa DSM 50090, Escherichia coli ATCC 8739 and Candida albicans CCMM-L4) with minimum inhibitory concentration (MIC) values within the range of 1.69–13.5 mg/mL. Moreover, this LPVC showed interesting scavenging effects on the 2,2-diphenyl-1-picrylhydrazyl radical with an IC₅₀ of 0.21 mg/mL. LPVCs could be an approving resource with moderate antimicrobial potential and interesting antioxidant activity for cosmetics and pharmaceutical applications. Full article

Critical loads of atmospheric deposition help decision-makers identify levels of air pollution harmful to ecosystem components. But when critical loads are exceeded, how can the accompanying ecological risk be quantified? We use a 90% quantile regression to model relationships between nitrogen and sulfur deposition and epiphytic macrolichens, focusing on responses of concern to managers of US forests: Species richness and abundance and diversity of functional groups with integral ecological roles. Analyses utilized national-scale lichen survey data, sensitivity ratings, and modeled deposition and climate data. We propose 20, 50, and 80% declines in these responses as cut-offs for low, moderate, and high ecological risk from deposition. Critical loads (low risk cut-off) for total species richness, sensitive species richness, forage lichen abundance and cyanolichen abundance, respectively, were 3.5, 3.1, 1.9, and 1.3 kg N and 6.0, 2.5, 2.6, and 2.3 kg S ha⁻¹ yr⁻¹. High environmental risk (80% decline), excluding total species richness, occurred at 14.8, 10.4, and 6.6 kg N and 14.1, 13, and 11 kg S ha⁻¹ yr⁻¹. These risks were further characterized in relation to geography, species of conservation concern, number of species affected, recovery timeframes, climate, and effects on interdependent biota, nutrient cycling, and ecosystem services. Full article

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. Full article

The importance of N₂-fixing arboreal cyanolichens to the nitrogen (N)-balance of sub-boreal interior hybrid spruce (Picea glauca × engelmannii) and subalpine fir (Abies lasiocarpa) forests was examined at field sites in central BC, Canada. Host trees were accessed by a single-rope climbing technique and foliage as well as arboreal macrolichen functional groups were sampled by branch height in eight random sample trees from each of two high (High Cyano) and two low (Low Cyano) cyanolichen abundance sites for a total of 32 sample trees. Natural abundances of stable isotopes of N (¹⁵N, ¹⁴N) and carbon (¹³C, ¹²C) were determined for aggregate host tree and epiphytic lichen samples, as well as representative samples of upper organic and soil horizons (Ae and Bf) from beneath host trees. As expected, N₂-fixing cyanolichens had 2–6-fold greater N-contents than chlorolichens and a δ¹⁵N close to atmospheric N₂, while foliage and chlorolichens were more depleted in ¹⁵N. By contrast, soils at all trees and sites were ¹⁵N-enriched (positive δ¹⁵N), with declining (not significant) δ¹⁵N with increased tree-level cyanolichen abundance. Lichen functional groups and tree foliage fell into three distinct groups with respect to δ¹³C; the tripartite cyanolichen Lobaria pulmonaria (lightest), host-tree needles (intermediate), and bipartite cyanolichens, hair (Alectoria and Bryoria spp.) and chlorolichens (heaviest). Branch height of host trees was an effective predictor of needle δ¹³C. Our results showed a modest positive correlation between host tree foliage N and cyanolichen abundance, supporting our initial hypothesis that higher cyanolichen abundances would elevate host tree foliar N. Further study is required to determine if high cyanolichen abundance enhances host tree and/or stand-level productivity in sub-boreal forests of central BC, Canada. Full article