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How lichens impact on terrestrial community and ecosystem properties
Abstract
Lichens occur in most terrestrial ecosystems; they are often present as minor contributors, but in some forests, drylands and tundras they can make up most of the ground layer biomass. As such, lichens dominate approximately 8% of the Earth’s land surface. Despite their potential importance in driving ecosystem biogeochemistry, the influence of lichens on community processes and ecosystem functioning have attracted relatively little attention. Here, we review the role of lichens in terrestrial ecosystems and draw attention to the important, but often overlooked role of lichens
as determinants of ecological processes. We start by assessing characteristics that vary among lichens and that may be important in determining their ecological role; these include their growth form, the types of photobionts that they contain, their key functional traits, their water-holding capacity, their colour, and the levels of secondary compounds in their thalli. We then assess how these differences among lichens influence their impacts on ecosystem and community processes. As such, we consider the consequences of these differences for determining the impacts of lichens on
ecosystem nutrient inputs and fluxes, on the loss of mass and nutrients during lichen thallus decomposition, and on the role of lichenivorous invertebrates in moderating decomposition. We then consider how differences among lichens impact on their interactions with consumer organisms that utilize lichen thalli, and that range in size from microfauna (for which the primary role of lichens is habitat provision) to large mammals (for which lichens are primarily a food source). We then address how differences among lichens impact on plants, through for example increasing nutrient
inputs and availability during primary succession, and serving as a filter for plant seedling establishment. Finally we identify areas in need of further work for better understanding the role of lichens in terrestrial ecosystems. These include understanding how the high intraspecific trait variation that characterizes many lichens impacts on community assembly processes and ecosystem functioning, how multiple species mixtures of lichens affect the key community and ecosystem-level processes that they drive, the extent to which lichens in early succession influence vascular plant succession and ecosystem development in the longer term, and how global change drivers may impact on ecosystem functioning through altering the functional composition of lichen communities.
... Endemic to the Florida scrub is the state's only federally endangered lichen, the Florida Perforate Lichen (Cladonia perforata) (Yahr, 2000). Lichens are symbiotic associations between fungus and green algae or cyanobacteria, and are found in most terrestrial ecosystems worldwide (Asplund & Wardle, 2017). They represent a relationship between heterotrophic mycobionts and at least one autotrophic photobiont (Asplund & Wardle, 2017). ...
... Lichens are symbiotic associations between fungus and green algae or cyanobacteria, and are found in most terrestrial ecosystems worldwide (Asplund & Wardle, 2017). They represent a relationship between heterotrophic mycobionts and at least one autotrophic photobiont (Asplund & Wardle, 2017). Compared to plants, lichen are usually minor contributors to net primary productivity in a habitat, however, in environments with harsh conditions such as extreme cold or aridity, lichen comprise much of the ground cover (Asplund & Wardle, 2017). ...
... They represent a relationship between heterotrophic mycobionts and at least one autotrophic photobiont (Asplund & Wardle, 2017). Compared to plants, lichen are usually minor contributors to net primary productivity in a habitat, however, in environments with harsh conditions such as extreme cold or aridity, lichen comprise much of the ground cover (Asplund & Wardle, 2017). Low-lying lichen often spread laterally and are slow-growing, making any loss of a population devastating to overall abundance (Hammer, 2001). ...
With the increased use of prescribed burns in recent years, it is critical to understand their impacts not only on their primary target species, but also on the entire biological community. Lichen have intricate symbioses with other neighboring organisms and provide important ecosystem services. In prairie and grassland environments, the prescribed burns may result in the extirpation of some ground-dwelling species of lichen. However, the impacts of fire schedules on the lichen recovery in Florida scrub remains unknown. The dry, sandy scrub ecosystem houses the only federally endangered lichen in the state, the Florida perforate lichen (Cladonia perforata). As scrub communities are adapted to the presence of fire, prescribed burns are now a routine management practice. Lichen has a key role in early plant succession following fire, influencing the health of Florida scrub. We used a modified Feests method to survey the effects of fire regime on terrestrial lichen abundance and diversity in the Lakeland Highlands Scrub, an area of scrub habitat in Polk County in Central Florida. The speed and comparable accuracy of Feests method render it an accessible means of assessing biodiversity for land management in protected areas. We estimated percent cover of lichen and estimated species diversity using the Lichen Diversity Value (LDV) in four areas of scrub and scrubby flatwoods habitat with different burn histories (unburned, two years, eight years, and ten years since last burn). According to the LDV calculations, diversity is highest in the most extreme temporal groups, contradicting our initial prediction that lichen diversity and abundance would be greatest in the intermediately disturbed areas (two and eight years post burn). These preliminary data suggest implementing prescribed burns more frequently in this scrub habitat would allow lichen communities a greater opportunity to recover. Our study yields beneficial information to assist future decisions made regarding the frequency of fire regimes within the Florida scrublands habitat. Methods of protecting lichen may also be recommended, such as collecting and removing lichen prior to a burn, and returning those lichen samples to the area after (e.g. Remove and Return).
... LF are composed by at least two different organisms, a fungus known as the mycobiont, an alga or photobiont and a diverse microbiota (Boustie et al. 2011;Zambare and Christopher 2012;Nguyen et al. 2013;Veres et al. 2022). LF are found in almost all terrestrial environments on Earth, including those too hostile for their separate bionts (Boustie et al. 2011;Zambare and Christopher 2012;Asplund and Wardle 2017;Beckett et al. 2021;Veres et al. 2022). LF are the dominant life-forms in c.a. 8% land surface, and high mountain environments are among the preferred sites of lichens (Boustie et al. 2011;Nguyen et al. 2013;Asplund and Wardle 2017;Beckett et al. 2021). ...
... LF are found in almost all terrestrial environments on Earth, including those too hostile for their separate bionts (Boustie et al. 2011;Zambare and Christopher 2012;Asplund and Wardle 2017;Beckett et al. 2021;Veres et al. 2022). LF are the dominant life-forms in c.a. 8% land surface, and high mountain environments are among the preferred sites of lichens (Boustie et al. 2011;Nguyen et al. 2013;Asplund and Wardle 2017;Beckett et al. 2021). ...
Lichens or lichenised fungi are particularly abundant in harsh environments, Neotropical Paramos are unique mountain environments located in the northern Andes, face several treats due to human activities and climate change. In this study, the antioxidant and photoprotective activities of 5 Paramo lichens were evaluated. Antioxidant activity was obtained using DPPH and FRAP assays. Photoprotective parameters (SPF Sun Protection Factor, critical wavelength, spectral amplitude) were determined spectrophotometrically. All extracts showed DPPH inhibition higher than 70% at 200 µg mL − 1 , while BHT achieved 92% at 20 µg mL − 1 and showed significant differences. Rock-inhabiting lichens such as Thamnolia and Cladonia performed better than phorophyte-growing lichens Lobariella , Peltigera and Everniastrum . Moreover, the extracts evaluated had moderate ferric ion reducing power and were statistically different from BHT. For protection against UV-B, the in vitro SPF were above 10 at 100 µg mL − 1 for all extracts except Peltigera . Lobariella was the most active at 100 and 200 µg mL − 1 (SPF: 17.37 ± 0.47 and 29.25 ± 1.68 respectively). Thamnolia , Cladonia and Lobariella can be highlighted as potential broad-spectrum filters (λ crit = 367.9; 364.2 and 355.8 nm), while Everniastrum can be proposed as UV-B and UVA-2 filter and Peltigera presented the smallest photoprotective activity. Consequently, Paramo lichens, especially species growing on rocks, soil or over exposed phorophytes can be proposed as sources of new photoprotective compounds, with the remarkable feature of their antioxidant capability, which is an improvement compared to synthetic sunscreens. These potential applications might help as conservation strategy for Paramo environments.
... We employed the classification guidelines established by Hale 36 to systematically categorize these growth forms into crustose, foliose, and fruticose ( Table 2). Crustose lichens are notably short, lack a lower cortex, and typically adhere tightly to the substrate, resembling a coat or paint 4,47 . Separating them from the substrate without causing damage can be challenging, and they can contribute to rock weathering through physical processes involving hyphal penetration, as well as expansion/contraction of the lichen thallus, along with chemical processes via the release of various organic acids 48 . ...
... Fruticose lichens display a bush-like, strap-shaped, or shrubby appearance, with the primary axis ranging from prostrate to erect. They commonly branch and are attached to the substrate by basal rhizoids 47 . Due to their dense thallus and complex vertical structures, they can regulate the temperature and humidity of their surroundings, providing roosting, living, and breeding spaces for other organisms 1 . ...
In the Antarctic, Arctic, and Tibetan Plateau—recognized as the Earth’s three poles characterized by extremely harsh environments—lichens prevail in the ecosystem and play crucial roles as pioneer species. Despite their importance, studies investigating the spatial distribution patterns of lichen attributes are scarce due to a lack of appropriate datasets. To bridge this gap and enhance our understanding of the growth preferences of lichens in these areas, here we present a geospatial dataset encompassing key attributes of lichens, such as color type and growth form, for over 2800 lichen species and 170,000 in-situ lichen records. The dataset facilitates the creation of the first spatial distribution map illustrating the variation of lichen attributes across different latitudes and longitudes. This can serve as a foundational resource for studies on the relationship between lichen types and their growing environment, which is a vital scientific question in the ecology domain. Additionally, it can contribute to the development of specialized remote sensing technique tailored for lichen monitoring, which is currently lacking.
... Lichens play an important ecological role in environmental monitoring. They have a rich species composition, occur in most terrestrial ecosystems, are resistant to harsh climates and have long life spans ranging from a few tens to hundreds or even thousands of years (Anderson et al., 2022;Asplund & Wardle, 2017;Lücking et al., 2017). ...
... Lichens are able to accumulate nutrients and enrich ecosystems with them. All this indicates that lichens are important components and drivers of ecosystem biogeochemistry (Asplund & Wardle, 2017). In addition, this makes them an important biomonitoring tool for recording the distribution and concentration of airborne radioactivity and pollutants (Anderson et al., 2022). ...
The presented work was aimed at studying the features of accumulation of radionuclides ²¹⁰Po and ²¹⁰Pb, as well as micro- (Cu, Pb, Zn, Ni, Ba, V, Ti, Sr) and macroelements (Mn, Fe, Al) by fruticose epiphytic (Bryoria spp., Usnea spp.) and epigeal (Cladonia spp.) lichens in the middle and northern taiga subzone of the European Northeast (Komi Republic, Russia). Lichens were collected from forests of seven municipalities. Areas with combined radiation and chemical pollution were also included in the study. The relevance of the study is related to the increasing anthropogenic load worldwide, insufficient data on the concentrations of the studied elements in the environment of Komi Republic, their potential toxicity, including high radioactive toxicity of ²¹⁰Po and ²¹⁰Pb, as well as the possibility of using these lichens for bioindication of various pollutants, including radioactive ones. It has been established that the accumulation of chemical elements by lichens differs both for areas with different technogenic loads, and for different ecological-substrate groups of lichens. Based on the data from correlation analysis, principal component analysis (PCA), as well as enrichment factors (EF) of lichens with chemical elements, the features of their intake into lichen thalli were studied. It was concluded that in the taiga zone epiphytes may be the preferable bioindicators of elements that enter the Earth's surface with air. Epigeal lichen Cladonia also showed good accumulating ability for ²¹⁰Po, ²¹⁰Pb, as well as microelements in areas with their high content in soils.
... Lichens make a significant contribution to global biodiversity (Hawksworth & Lücking 2017;Lücking et al. 2017a) and support important ecosystem functioning from local (Asplund & Wardle 2017) to global scales (Elbert et al. 2012;Porada et al. 2014). Lichens play a key role in carbon and nitrogen dynamics, chemical weathering (Asplund & Wardle 2017;Elbert et al. 2012;Nash 2008), pedogenesis and seedling establishment (Houle & Filion 2003). ...
... Lichens make a significant contribution to global biodiversity (Hawksworth & Lücking 2017;Lücking et al. 2017a) and support important ecosystem functioning from local (Asplund & Wardle 2017) to global scales (Elbert et al. 2012;Porada et al. 2014). Lichens play a key role in carbon and nitrogen dynamics, chemical weathering (Asplund & Wardle 2017;Elbert et al. 2012;Nash 2008), pedogenesis and seedling establishment (Houle & Filion 2003). They also provide microhabitats and substrate for diverse organisms and are a source of food for herbivores and invertebrates (Boertje 1984;Nash 2008). ...
Conservation of lichens is impeded by knowledge gaps on their distribution and habitat requirements. This is a significant issue in vast, isolated and harsh environment regions such as subarctic regions, where lichen communities remain under documented. Lichen biodiversity assessments provide useful insights to better understand the functions supported by these ecologically important and sensitive species. This study aims i) to describe the conservation status of lichen communities and their α- and β-diversity components across a subarctic region in Northern Quebec (190 km ² ), ii) to describe their functional traits across the habitat types found in this region, and iii) to identify habitat types constituting lichen biodiversity hotspots. Lichens were sampled in 45 plots in habitats ranging from coniferous and deciduous forests to bogs, fens and rocky outcrops. A total of 115 species of largely macrolichens, calicioid lichens and allied fungi were identified, of which 18% currently have ranks of conservation concern at the provincial level, and 38% are newly reported for the region (~124,000 km ² around our study area). Richness across plots averaged 36 ± 9 species and plots richer in microhabitats often harbored more species (R ² = 0.22). Differences in species composition were identified among plots and habitat types through NMDS and perMANOVA analyses (R ² = 0.35; p < 0.001), both being supported by differences in microhabitat composition (Mantel r = 0.22 and perMANOVA R ² = 0.29, respectively; p < 0.001). Thirty-five species showed significant preferences for a habitat based on the Pearson’s phi coefficient of association. Our analysis on functional traits revealed significant patterns of association with habitat types, including i) saxicolous species with rocky outcrops, ii) epiphytic/epixylic species and vegetative reproduction traits (soredia, isidia) with coniferous stands, and iii) species belonging to the Parmeliaceae family with fens. Rocky outcrops represented the main lichen biodiversity hotspots in the region, while other habitat types were also important for maintaining total and complementary biodiversity. We are confident that our methodological approach including systematic sampling, full habitat variability representation, and the evaluation of complementary biodiversity components, can be effectively applied to fill gaps on lichen biodiversity in other underexplored regions across the globe.
... Lichens make a significant contribution to global biodiversity (Hawksworth & Lücking 2017;Lücking et al. 2017a) and support important ecosystem functioning from local (Asplund & Wardle 2017) to global scales (Elbert et al. 2012;Porada et al. 2014). Lichens play a key role in carbon and nitrogen dynamics, chemical weathering (Asplund & Wardle 2017;Elbert et al. 2012;Nash 2008), pedogenesis and seedling establishment (Houle & Filion 2003). ...
... Lichens make a significant contribution to global biodiversity (Hawksworth & Lücking 2017;Lücking et al. 2017a) and support important ecosystem functioning from local (Asplund & Wardle 2017) to global scales (Elbert et al. 2012;Porada et al. 2014). Lichens play a key role in carbon and nitrogen dynamics, chemical weathering (Asplund & Wardle 2017;Elbert et al. 2012;Nash 2008), pedogenesis and seedling establishment (Houle & Filion 2003). They also provide microhabitats and substrate for diverse organisms and are a source of food for herbivores and invertebrates (Boertje 1984;Nash 2008). ...
Conservation of lichens is impeded by knowledge gaps on their distribution and habitat requirements. This is a significant issue in vast, isolated and harsh environment regions such as subarctic regions, where lichen communities remain under documented. Lichen biodiversity assessments provide useful insights to better understand the functions supported by these ecologically important and sensitive species. This study aims i) to describe the conservation status of lichen communities and their α- and β-diversity components across a subarctic region in Northern Quebec (190 km2), ii) to describe their functional traits across the habitat types found in this region, and iii) to identify habitat types constituting lichen biodiversity hotspots. Lichens were sampled in 45 plots in habitats ranging from coniferous and deciduous forests to bogs, fens and rocky outcrops. A total of 115 species of largely macrolichens, calicioid lichens and allied fungi were identified, of which 18% currently have ranks of conservation concern at the provincial level, and 38% are newly reported for the region (~124,000 km2 around our study area). Richness across plots averaged 36 ± 9 species and plots richer in microhabitats often harbored more species (R2 = 0.22). Differences in species composition were identified among plots and habitat types through NMDS and perMANOVA analyses (R2 = 0.35; p < 0.001), both being supported by differences in microhabitat composition (Mantel r = 0.22 and perMANOVA R2 = 0.29, respectively; p < 0.001). Thirty-five species showed significant preferences for a habitat based on the Pearson’s phi coefficient of association. Our analysis on functional traits revealed significant patterns of association with habitat types, including i) saxicolous species with rocky outcrops, ii) epiphytic/epixylic species and vegetative reproduction traits (soredia, isidia) with coniferous stands, and iii) species belonging to the Parmeliaceae family with fens. Rocky outcrops represented the main lichen biodiversity hotspots in the region, while other habitat types were also important for maintaining total and complementary biodiversity. We are confident that our methodological approach including systematic sampling, full habitat variability representation, and the evaluation of complementary biodiversity components, can be effectively applied to fill gaps on lichen biodiversity in other underexplored regions across the globe.
... Although the possibility of precipitation of lichen secondary metabolites from the thallus into the soil has been proved experimentally (Malicki 1965;Dawson et al. 1984;Garcia-Junceda and Filho 1986;Zagoskina et al. 2013), their allelopathic potential, although established (Malicki 1967(Malicki , 1970, is questioned in terms of the extracted metabolite concentrations (Asplund and Wardle 2017) and their lack of antimicrobial activity in soil (Stark and Hyvärinen 2003;Stark et al. 2007). The latest hypothesis is highlighted in the light of mycelium growth dynamics in macromycetes influenced by the stimulating effect of lichen-extracted substances (Furmanek et al. 2022a). ...
... It is likely that suitable conditions for this occur during the heavy rain that soaks into the lichen thalli and the subsequent solar insolation following the rainfall. Certain ecological niches, such as bryophyte-lichen mats in dry and fresh coniferous forests, favor water accumulation (Asplund and Wardle 2017;Klamerus-Iwan et al. 2020), which may determine the infiltration of lichen substances from the lichen thalli into the soil substrate (Malicki 1965). Extracts from lichen species that share the same chemistry as Cladonia phyllophora, C. subulata, and C. gracilis by the presence of fumarprotocetraric acid, showed various phenol concentrations which might be determined by external factors. ...
Main conclusion
Rainwater most probably constitutes a relatively effective solvent for lichen substances in nature which have the potential to provide for human and environmental needs in the future.
Abstract
The aims were (i) to test the hypothesis on the potential solubility of lichen phenolic compounds using rainwater under conditions that partly reflect the natural environment and (ii) to propose new and effective methods for the water extraction of lichen substances. The results of spectrophotometric analyses of total phenolic metabolites in rainwater-based extracts from epigeic and epiphytic lichens, employing the Folin–Ciocalteu (F.–C.) method, are presented. The water solvent was tested at three pH levels: natural, 3, and 9. Extraction methods were undertaken from two perspectives: the partial imitation of natural environmental conditions and the potential use of extraction for economic purposes. From an ecological perspective, room-temperature water extraction (‘cold’ method) was used for 10-, 60-, and 120-min extraction periods. A variant of water extraction at analogous time intervals was an ‘insolation’ with a 100W light bulb to simulate the heat energy of the sun. For economic purposes, the water extraction method used the Soxhlet apparatus and its modified version, the ‘tea-extraction’ method (‘hot’ ones). The results showed that those extractions without an external heat source were almost ineffective, but insolation over 60- and 120-min periods proved to be more effective. Both tested ‘hot’ methods also proved to be effective, especially the ‘tea-extraction’ one. Generally, an increase in the concentration of phenolic compounds in water extracts resulted from an increasing solvent pH. The results show the probable involvement of lichen substances in biogeochemical processes in nature and their promising use for a variety of human necessities.
... Intact forest ecosystems and wilderness areas are paramount to long-term sustainability of biological diversity, ecological processes, ecosystem services, and indigenous cultures (Di Marco et al., 2019;Watson et al., 2018). Lichens and bryophytes can be found in almost any terrestrial ecosystem on Earth; they are especially abundant at higher latitudes, where they have major impacts on biogeochemical cycles and ecosystem functions (Asplund and Wardle, 2017;Porada et al., 2014). Moreover, lichen and bryophyte communities are sensitive to environmental changes (Hawksworth and Rose, 1970;Lang et al., 2012;Nascimbene and Spitale, 2017) and can be useful to monitor the current biodiversity crisis and the efficiency of policies intended to avert it (Miller et al., 2020;Outhwaite et al., 2019;Pakeman et al., 2019). ...
... The boreal forest includes some of the largest remaining areas on Earth with very low anthropogenic impact (Gauthier et al., 2015), where lichens and bryophytes are conspicuous features of the ecosystem (Asplund and Wardle, 2017;Turetsky et al., 2012). Forests that have been historically exempt of severe anthropogenic activities, such as industrial timber harvesting or mining, have a high degree of ecological continuity and often host unusual sets of specialist species (Fritz et al., 2008;Selva, 2003;Wiersma and McMullin, 2019). ...
Lichens and bryophytes are ubiquitous in terrestrial habitats, sensitive to environmental changes, and they
contribute to ecosystem functions and biogeochemical cycles. Intact forest ecosystems host distinct biotic
communities that are associated with microhabitat and structural diversity at stand and landscape scales. In the
boreal region of eastern Canada, insect outbreaks and clearcutting (the dominant timber harvesting method) are
common disturbances. However, while insect outbreaks from native species can maintain ecological continuity,
clearcutting disrupts it and homogenizes forest structure. We compared lichen and bryophyte communities between
old-growth forest stands and 50 years-old stands regenerated from clearcuts and insect outbreaks. From
these communities, liverwort and deadwood specialist species richness was higher in insect outbreak and oldgrowth
than in clearcut forest stands. Stand type explained 10.3 % and 7.0 % of the variability observed in
liverwort and deadwood specialist community composition, respectively. Clearcut stands were responsible for
most of this variability since communities had less unique species and lacked some of the most common species
found in old-growth and insect outbreak stands. Indeed, many species associated with deadwood and ecological
continuity appeared unable to recolonize forest stands between planned intervals of clearcut rotations (i.e. ~50
to 60 years in our study area). However, deadwood volume did not differ between stand types and could not
explain any part of the observed variability in the composition of communities. We suggest that forests regenerating
from insect outbreaks are a suitable alternative for biological conservation in regions where old-growth
forests are rare, especially for liverworts and deadwood specialists.
... Dust can be an important contributor of rock-derived nutrients (base cations and P) to ecosystems in arid and semi-arid regions (Arvin et al., 2017;Brahney et al., 2014). In our study, concentrations of P in lichens were not correlated to distance (Figure 7b) which could indicate that dust does not bring P into vegetation at Lhù'ààn Mân' despite the ability of Peltigera lichens to accumulate high P concentrations in their thalli (Asplund & Wardle, 2017) or that the trends shown are insignificant relative to the input expected from dust. For example, P concentrations are lower (average of 443 mg kg 1 ) in Lhù'ààn Mân' soils compared to P concentrations (3,000 mg kg 1 ) in dust and lake sediments (1,000-5,000 mg kg 1 ) in the Wind River Range watershed in Wyoming reported by Brahney et al. (2014). ...
... We found carbon and N concentrations in lichens increase with distance from the dust source ( Figure 7b) suggesting that N is not deposited in the ecosystem. The high N concentrations measured in lichens in our study might be explained by a large amount of N fixed by Peltigera lichens which often occurs in arctic environments (Asplund & Wardle, 2017;Gunther, 1989) thus increasing C concentrations and C assimilation capacity (Palmqvist et al., 2002). ...
Dust is a mineral aerosol of the atmosphere that often contains trace elements such as As, Cd, and Pb. Lhù’ààn Mân’ (Kluane Lake), located in southwestern Yukon, is a region of frequent dust activity. In 2016, the lake level fell due to a dramatic decrease in inflow from glacier meltwater, and the delta of the lake became an important source of dust to surrounding ecosystems. To determine the impacts of dust deposition on vegetation and soil trace element concentrations and characteristics, we sampled the lichen Peltigera canina and soil layers at 57 sites along a deposition gradient located 1.4–33.6 km downwind from the principal dust source. Arsenic, Cd, Cu, Ni and Pb in lichens were negatively correlated with the distance away from the dust source, with the highest correlations in Ni and Pb (r² = 0.50 and 0.48, respectively). Lichen and tree abundances were negatively impacted by dust deposition, suggesting that dust can affect ecosystem vegetation composition. Starting 8 km away from the dust source, the concentrations of As, Ni, and Pb decreased by more than 50% per km, while Cd and Cu concentrations decreased by more than 40% per km. Overall, within the sampled ecosystems, soil pH is 1.4 times higher in the first 8 km from the dust source while carbon content and nutrients are lower, which implies changes in nutrient availability and cycling in dust‐affected ecosystems.
... Lichens play important roles within forest habitats through their contribution to biological diversity and by driving ecological and biogeochemical processes (Asplund & Wardle 2017;Vondrák et al. 2019). Additionally, lichens provide additional biomass in forest habitats, are used as food and shelter for wildlife and are valuable forest continuity indicators (Asplund & Wardle 2017;Miller et al. 2020). ...
... Lichens play important roles within forest habitats through their contribution to biological diversity and by driving ecological and biogeochemical processes (Asplund & Wardle 2017;Vondrák et al. 2019). Additionally, lichens provide additional biomass in forest habitats, are used as food and shelter for wildlife and are valuable forest continuity indicators (Asplund & Wardle 2017;Miller et al. 2020). Furthermore, lichens are traditionally used by humans as feed and for other purposes, such as therapeutic, ceremonial, religious, and veterinary (Devkota et al. 2017). ...
The European forestry landscape represents an important priority for biodiversity and needs adequate management strategies. The main focus of this review is the importance of European forest areas for epiphytic lichen richness under the impact of different management practices assessed in the biogeographical and ecological regions of Europe. In total, 88 scientific articles were reviewed (based on the first author’s archive and by query in Web of Science), which examined epiphytic lichen richness within managed and unmanaged European forests. Biogeographical and ecological regions of Europe were not taken into account in the reviewed articles, but we used them for statistical analyses in the present work according to the geographical position of the investigated sites published in the reviewed articles. We also analysed the dissimilarities in epiphytic lichen richness among European biogeographical and ecological regions. Additionally, we analysed the impact of different silvicultural management practices (within assessed forests) on epiphytic lichen richness across the different biogeographical and ecological regions of Europe. The main results indicate that epiphytic lichen richness is significantly different across the biogeographical and ecological regions of Europe. Epiphytic lichen richness is significantly greater in Western European broadleaf forests in the Carpathian and Caledonian mountain areas and significantly lower in the Central European mixed forests and East European forest steppe. Management practices applied within studied forests had a negative impact on epiphytic lichen richness, while epiphytic lichen richness was higher within unmanaged forests. The main conclusion is that forests within highland areas of Europe that are not subjected to anthropogenic activities or management practices harbour greater epiphytic lichen richness and therefore should be conserved and protected due to their biological and ecological importance.
... These numbers are relevant for the studied ecosystem given that lichens, together with bryophytes, contribute significantly to carbon and nitrogen fixation (Elbert et al., 2012). Lichens also show a remarkable ability to uptake and retain atmospheric water and provide shelter and food for a multitude of microbial and microarthropod communities (Cornelissen et al., 2007;Asplund & Wardle 2017). Furthermore, the diversity of lichenized fungi in the Penyagolosa Massif and nearby areas represents ca. ...
The Penyagolosa Massif (Castelló, Valencian Community), which includes the Penyagolosa Natural Park, is one of the most emblematic natural landscapes of the eastern Iberian Peninsula. It hosts a wide variety of Mediterranean habitats, including groves of several Quercus species and extensive Pinus spp. forests. The present checklist represents the first compilation of lichenized and lichenicolous fungi for the protected as well as nearby areas and is mostly based on species records available at the Biodiversity Data Bank of the Generalitat Valenciana (BDBCV). We report 221 and 12 infrageneric taxa of lichenized and lichenicolous fungi, respectively. Punctelia caseana is reported for the first time for the European continent. Six lichenicolous fungi are newly reported for the Valencian Community. The study area includes the red-listed lichen Xanthoparmelia camtschadalis. The families Parmeliaceae and Teloschistaceae showed the highest species richness. By evaluating the functional traits, we found that the most diverse lichens are those showing (1) crustose thalli, (2) with a sexual reproduction, mainly through the formation of apothecia, and (3) that are associated with trebouxioid green microalgae. Furthermore, the most frequent lichen community in the study area is formed by xerophytic lichens that can tolerate very high direct solar irradiation and develop under weak eutrophication conditions. Finally, we emphasize the need to accelerate the compilation of the diversity of lichenized and lichenicolous fungi in the park through DNA sequencing and molecular phylogenetics, which will also allow revealing the diversity of associated lichen photobionts and fungal-algal interaction patterns.
... Thus, the outcomes of changing snow patterns will be unpredictable, as tolerance of snow cover can differ even between lichen species of the same genus, growing in adjacent microhabitats 35 . It is important to understand future species-specific climate change impact on lichens because they make major contributions to ecosystem properties 36 , comprise the food source of animals 37,38 and are used by local people for food, beverages and traditional medicine 39,40 . ...
Trans-Himalayan winters are projected to become milder, with shifting precipitation patterns and freeze-thaw cycles; changing stressors for their lichen communities. Lichens from Antarctica and high latitudes are cryoresistant when dry, but susceptible to cell damage if frozen when wet, or subjected to repeated freeze-thaw events. Little is known regarding cryoresistance in high-elevation, mid-latitude lichens. We collected thalli of nine species of epiphytic lichenized fungi, from three regions of the trans-Himalayas; at ≈ 4000 m, 3400 m and 2400 m elevation. We subjected thalli to differing freezing (continuous − 18 °C and − 36 °C or freeze-thaw cycles in natural daylight) and moisture conditions. Even dry thalli suffered some damage. Frozen wet thalli had greater chlorophyll degradation and reduced chlorophyll content. There were no clear elevational trends in freeze-thaw susceptibility: it caused more damage than continuous freezing. The most freeze-thaw resilient lichens were Dolichousnea longissima (from 4000 m) and Usnea florida (from 2400 m). However, species from coldest sites were most resilient to extreme freezing. Under predicted climate change conditions these sites would experience fewer annual freeze-thaw cycles, annual sub-zero days and frost days. Reduced freezing constraints might allow range expansion of mid-elevation lichens, but increase competitive pressures and temperature stressors impacting high-elevation lichens.
... Lichens-obligate symbioses between at least one fungus and an alga or cyanobacterium-are essential to ecosystem processes (Asplund & Wardle, 2017). They are sensitive to air pollution (Jovan & McCune, 2005) and to anthropogenic disturbance Tripp et al., 2019) allowing them to be used as bioindicators for both air quality and forest continuity (Miller et al., 2020;Wiersma & McMullin, 2022). ...
Cliffs support rare, endemic, and glacial relict vegetation that may differ from vegetation in surrounding forests. Yet, cliffs are difficult to sample, and rock-dwelling lichens can be challenging to identify; therefore, cliff lichens are often excluded from biodiversity studies. This omission creates fundamental gaps in our understanding of cliff lichens that lead to underestimation of overall community diversity. This study addresses one such gap by asking a basic question: do lichen communities on cliffs differ from rock-dwelling lichen communities in forests? To answer this question, we compared lichen communities from three cliffs in the Linville Gorge (North Carolina, USA; 369 m2 of cliff face surveyed) to rock and soil-dwelling lichen communities in forested plots across the same region (Southern Appalachian Mountains, USA, Alabama to North Carolina; 198 1-hectare forested plots). Forest plots were further divided into three groups based on elevation, proximity to Linville Gorge cliffs, and location within the state of North Carolina. A total of 225 rock or soil-dwelling lichen species were found in forest plots throughout the study area, while 104 species were found on cliffs. Two rare cliff-specialist species, Canoparmelia alabamensis, and Chrysothrix susquehannensis, were locally abundant on the studied cliffs but absent from surrounding forests. Our results show that cliffs support 20% of regional rock-dwelling lichen diversity, and that these cliff communities are distinct from those in forests. The high diversity, occurrence of unique species, and presence of rare lichens on cliffs indicate that cliff lichens should be included in biodiversity inventories and stewardship plans. To support this inclusion, we provide the first checklist for the lichens of Linville Gorge. Checklists like this one, including both cliff and non-cliff lichens, provide data on regional diversity and rarity that inform lichen conservation and rock climbing management.
... The build-up of high standing crop in these lichens is driven by the availability and longevity of suitable substrates and specific microclimates, and takes several decades due to slow growth, dispersal limitation and stochastic mortality (Esseen et al., 1996;Ellis, 2012;Esseen and Ekström, 2023). Hair lichens have important ecosystem functions in forests by providing fodder and habitat for animals (Pettersson et al., 1995;Asplund and Wardle, 2017), by influencing canopy microclimate (Pypker et al., 2017) and through interactions with stand-level hydrology and element cycling (Van Stan and Pypker, 2015;Porada et al., 2013Porada et al., , 2018Hembre et al., 2021). These lichens are key resources for reindeer and caribou in winter (Johnson et al., 2000;Heggberget et al., 2002;Horstkotte et al., 2011). ...
Hair lichens in the genera Alectoria and Bryoria dominate old-growth circumboreal coniferous forests and have important ecosystem functions, particularly for reindeer and caribou. These lichens are sensitive to changes in climate and are unable to maintain a high standing crop in industrial forestry based on clear-cutting, highlighting the need of management models based on continuous cover forestry. We examined how dry mass (DM) growth and CO2 exchange in hair lichens depended on the balance between growth (carbon gain from photosynthesis) and losses (both carbon loss from respiration and mass loss from fragmentation). Partial cutting trials were conducted in a Picea abies-dominated forest by three levels of basal area (BA) removal (0%; 33%; 67%), with five 80 m x 80 m plots per level. We compared two species with similar functional traits but with different cortical pigments, the pale Alectoria sarmentosa and the dark Bryoria fremontii. Lichens were transplanted within the lower canopy using net cages over a 1-year period to evaluate net growth, loss by thallus fragmentation and gross growth. Canopy openness and transmitted radiation during the growing season were estimated from hemispherical photographs. Canopy temperature, relative humidity, and photosynthetic photon flux density were monitored, with microclimate data subsequently used to model net CO2 exchange using previously published response matrices describing net photosynthetic and respiratory activity. Net DM growth of A. sarmentosa was higher than in B. fremontii, and increased with level of BA removal, being twice as high in the 67% BA removal as in the control. In contrast, B. fremontii responded weakly to partial cutting due to high rates of thallus fragmentation. However, gross growth of both species increased with canopy openness and transmitted radiation. The modelled net assimilation showed large seasonal variation, with the largest difference among levels of BA removal in autumn. The estimated DM growth agreed well with observed gross growth in A. sarmentosa but was underestimated in B. fremontii. Modelling of CO2 exchange can provide a mechanistic understanding of how hair lichens respond to partial cutting and climate change. The response of hair lichens to microclimate in partial cuts depends on the trade-off between growth and losses. Results suggest that the faster lichen growth on residual trees in the one-third removal partial cuts compensated to a significant degree for the loss of lichen mass by the removal of host trees.
... Lichens are common components of terrestrial environments, and can have a range of impacts on ecosystem processes (Asplund and Wardle, 2017). In arid and semi-arid environments, lichens contribute to rock weathering (Guglielmin et al., 2011;Lopez and Bacilio, 2020), nutrient cycling and availability (Evans and Ehleringer, 1993;Rogers et al., 1966;Root et al., 2021;Tian et al., 2023), and soil stabilization (Lopez and Bacilio, 2020;Rodriguez-Caballero et al., 2022). ...
The Tswalu Kalahari Reserve in the Northern Cape Province of South Africa has no previously published data on its lichen biota, which reflects the broader status of lichenology in South Africa. It is estimated that nearly half of the country's lichen species remain undescribed. Consequently, this study aimed to gather baseline data on lichen diversity and distribution across the reserve. We quantified morphological and functional diversity, characterized lichen communities, and analyzed relationships between lichen diversity and environmental variables (northness, coverage, elevation, insolation, site, substrate type, and substrate texture) using morphospecies concepts. We documented 49 morphospecies across three habitats in the Tswalu Kala-hari Reserve, including at least one species that is new to science (Caloplaca tswaluensis Fryday, S. Svoboda & D. A. Ward; Fryday et al. in press) and another (Trapeliopsis glaucolepidea (Nyl.) Gotth. Schneid.) that had not previously been reported from Africa. Overall, we recorded lower diversity in corticolous (bark dwelling) lichen communities compared to saxicolous (rock dwelling) lichen communities. However, we did not find a significant effect of any measured environmental variable on saxicolous species richness. This preliminary study underscores the need for further investigation of the diverse, unrecorded lichen diversity that likely exists in other areas of the country as well as the differences in lichen communities on bark and rock sub-strates. This study also shows that morphospecies concepts can be informative and accessible approaches for exploratory lichen studies, particularly in regions with relatively understudied cryptogam communities.
... Deserts, representing arid environments with poor soil nutrients (Hu et al., 2003), offer unique advantages for biological soil crusts (BSCs) (Schulz et al., 2016). BSCs are estimated to cover approximately 12% of the Earth's land surface (Rodriguez-Caballero et al., 2018), and lichens play a crucial role in these environments by promoting nutrient cycling and improving soil physical stability (Asplund and Wardle, 2017;Moreno-Jiménez et al., 2020). ...
Soil salinization is a major environmental threat to the entire terrestrial ecosystem. Lichens arose from the symbiosis of fungi and algae or cyanobacteria. They have a high tolerance to various extreme environments, including adaptation to saline‐alkali habitats. Thus, lichens are pioneer species on saline‐alkali soil. However, the separate resilience of the two symbiotic partners under saline‐alkali conditions remains insufficiently understood. In this study, two representative symbiotic algae, Diplosphaera chodatii and Trebouxia jamesii , were studied for their physiological response to the saline‐alkali stress by adjusting different concentrations of NaHCO 3 , together with their respective symbiotic fungi Endocarpon pusillum (terricolous lichen) and Umbilicaria muhlenbergii (saxicolous lichen). The results indicate that cell growth rate and biomass in all four cultures decreased in alkali‐alkaline substrate, while cellular activities and ultrastructure were affected to a distinct extent. Compared with the symbiotic fungi, the algae were found to be more active in coordinating oxidative stress and lipid peroxidation damage under the saline‐alkali stress. The antioxidant system of the alga was especially shown as a key adaptive trait and it provides an important strategy for species survival and persistence in arid saline‐alkali desert. The specific survival ability of the lichen symbiosis relies on the stress resilience advantages of the symbiotic partners in combination. Our study provided new insights into understanding the adaptation of lichen symbiosis to desert saline‐alkali soil, and the potential of lichen symbiotic algae in the future desert ecological restoration.
... Temperate forests harbour more than a hundred, often several hundred species of lichen-forming fungi (Jüriado et al. 2003;Coppins and Coppins 2005;Boch et al. 2013;Lõhmus and Lõhmus 2019). The lichen communities contribute to forest ecosystem function by retaining water (Van Stan and Pypker 2015), cycling minerals and nutrients (Pike 1978;Reiners and Olson 1984;Knops et al. 1991Knops et al. , 1996Campbell et al. 2010), being part of the food web and providing habitat and micro-niches for other organisms (reviewed in Ellis (2012) and Asplund and Wardle (2017)). Forest lichen communities respond to abiotic environmental changes (Miller et al. 2018;Łubek et al. 2021), as well as to forest management (Nascimbene et al. 2013;Boch et al. 2021). ...
Lichens are an important part of forest ecosystems, contributing to forest biodiversity, the formation of micro-niches and nutrient cycling. Assessing the diversity of lichenised fungi in complex ecosystems, such as forests, requires time and substantial skills in collecting and identifying lichens. The completeness of inventories thus largely depends on the expertise of the collector, time available for the survey and size of the studied area. Molecular methods of surveying biodiversity hold the promise to overcome these challenges. DNA barcoding of individual lichen specimens and bulk collections is already being applied; however, eDNA methods have not yet been evaluated as a tool for lichen surveys. Here, we assess which species of lichenised fungi can be detected in eDNA swabbed from bark surfaces of living trees in central European forests. We compare our findings to an expert floristic survey carried out in the same plots about a decade earlier. In total, we studied 150 plots located in three study regions across Germany. In each plot, we took one composite sample based on six trees, belonging to the species Fagus sylvatica, Picea abies and Pinus sylvestris. The eDNA method yielded 123 species, the floristic survey 87. The total number of species found with both methods was 167, of which 48% were detected only in eDNA, 26% only in the floristic survey and 26% in both methods. The eDNA contained a higher diversity of inconspicuous species. Many prevalent taxa reported in the floristic survey could not be found in the eDNA due to gaps in molecular reference databases. We conclude that, currently, eDNA has merit as a complementary tool to monitor lichen biodiversity at large scales, but cannot be used on its own. We advocate for the further development of specialised and more complete databases.
... The alga has its own scientific name which has no relationship with the lichen or fungus. There are about 20,000 known lichen species -or rather, fungi involved in symbiotic relations with algae and / or cyanobacteria photobionts -and it is estimated that 6~8% of Earth's land surface is covered by lichens (Asplund & Wardle, 2017). The mycobiont is a heterotrophic species that depends on organic carbon supplying and eventual growth factors from the autotrophic photobiont, that is able to fix carbon dioxide (CO2) from the atmosphere and consequently produce organic compounds thanks to the photosynthetic activity (Nash, 1996). ...
... The lichens in the evergreen forest reach a high biomass that make them a visible and important component of the forest ecosystem [4], which is possible due to an optimal combination of water regime and temperature [5], constituting a relevant contribution to local biodiversity [4,6,7]. Epiphytic lichens are an important group of organisms in forest ecosystems [8,9] and show high specificity to host species and the microhabitats offered by the phorophyte trees [10,11]. Lichens are poikilohydric organisms and therefore lack mechanisms that regulate the absorption and loss of water [12]. ...
The Valdivian region has a temperate rainy climate with differences in rainfall throughout the year. This heterogeneity results in periods of summer drought that expose the poikilohydric epiphytes to desiccation. With this research, we aim to answer different research questions related to phorophyte preference, response to desiccation, and response to radiation. How does the diversity of macrolichens vary at a local and microclimate scale in three tree species within an evergreen forest? What is the tolerance limit of macrolichens against prolonged desiccation, according to evaluation of the maximum efficiency of PSII (Fv/Fm) and pigment concentration? What is the tolerance limit against a potential increase in radiation? We found that macrolichen communities are determined by tree species, which regulate the suitability of the substrate by modifying the temperature and humidity conditions. In addition, our results show a rapid photosynthetic alteration in temporal exposure to desiccation, measured through Fv/Fm and pigment concentration. Our results showed that the most sensitive lichens to radiation and desiccation are not coincident. We confirm the low tolerance of macrolichen species to high radiation, reflected in the saturation profile obtained for the set studied. The lichen community in the evergreen forest showed high complexity and vulnerability, pointing to the importance of more research.
... One of the most common symbiotic associations between microalgae and fungi that occur readily in nature, that are counted among the first biological colonizers of barren terrestrial environments and used as atmospheric bio-indicators are lichens (Fig. 5.3) (Asplund & Wardle, 2017;Conti & Cecchetti, 2001). Indeed, several Trebouxiophyceae members, the class to which the Chlorella genus-one of the most widely implemented microalgae in MWWTS-belongs, are lichen photobionts ( Fig. 5.3d, e) (Muggia et al., 2018). ...
There is a considerable variety of research on microalgae-based wastewater treatment systems (MWWTS). This chapter discusses the diverse microbial associations that have been applied to MWWTS as well as the role of other biological players, such as zooplankton and viruses. Although microalgal-bacterial associations are widely studied, others such as microalgal-fungal are now receiving increasing attention. The metabolisms of photosynthetic microalgae and aerobic bacteria complement each other, increasing the overall efficiency of MWWTS. Statistical meta-analyses of the literature data indicate that microalgal-bacterial and microalgae-only wastewater treatment systems remove significantly different percentages of COD (paired t-test, t21 = 4.138, P < 0.001), TN (paired t-test, t10 = 3.61, P = 0.004), and TP (paired t-test, t15 = 2.37, P = 0.031). Meanwhile, microalgae and fungi are readily pelletized and accumulate large amounts of lipids, which can be used for biofuel production. On the other hand, zooplankton and viruses can also be present in MWWTS, interacting with the implemented consortia. The presence of zooplankton communities can compromise MWWTS; however, several zooplankton control techniques have been studied and are effective at optimizing the MWWTS process. Regarding aquatic viruses in MWWTS, more research should be conducted given the roles of virioplankton and their interactions with microalgae in naturally occurring water bodies. Independently of the important roles of different organisms (aerobic-anaerobic) on wastewater treatment, the presence of other microorganisms such as microalgae improves different wastewater treatment processes. Thus, more research is needed on the use of different microalgae, bacteria and fungi species to enhance the removal of different pollutants (including toxic and persistent compounds) and micronutrients, while providing oxygen to the system and consuming CO2, reducing the need for mechanical aeration and fixing CO2 from the environment.
... They are key organisms in ecosystem functioning, since they are primary producers involved, for example, in water and nutrient cycles (Pike 1978, Porada et al. 2018. Several interactions are known to occur between lichens and animals (Asplund & Wardle 2017). Lichens can be a feeding substrate for both some vertebrates and several invertebrates. ...
Red wood ants (RWA) are ecologically important keystone species that affect a multitude of taxa at different trophic levels. In the past century, some RWA species were used as biological control agents and exported outside their native range. One of these species is Formica paralugubris, which was transplanted from the Italian Alps to the Apennines (Central Italy) but also to Quebec (Canada). Recently, it has been demonstrated that some of the introduced populations have acquired some
invasivity features.
This PhD thesis investigated the ecology of Formica paralugubris, aiming to assess its impact at multiple levels, from single taxa to the forest ecosystem as a whole. To do this, I combined different techniques, from direct observations to gas analysis and stable isotopes analysis. I started with assessing the effect of the presence of this species on epiphytic lichen communities, and I analyzed the myrmecophilous fauna inhabiting the nest mounds of introduced and autochthonous populations. I then compared the trophic position of native and introduced populations of this species, using Stable Isotopes Analysis (SIA) techniques. Finally, I characterized the microbial
communities hosted within the nest mounds using molecular techniques and I measured the gas emissions from the mounds. To conclude, I have done an overview of the protection status of RWA throughout Europe.
Overall, the results of this thesis confirm the ecological importance of F. paralugubris. This species was shown to affect the composition of lichen communities, both from a taxonomic and a functional point of view. Its nest mounds host a rich myrmecophilous fauna and diverse microbial communities. The species was also found to occupy key positions in the trophic web and to play an important role in the carbon dynamics at the forest scale. These results were also discussed in light of the nature of F. paralugubris as a peculiar invasive species. Finally, the complex status of RWA protection was highlighted, also pointing out paradoxical situations in which the introduced populations are protected whereas the native and sometimes declining ones are not.
... Lichens are fungi that form mutualistic symbioses with photosynthesizing organisms (Spribille & al., 2022) and whose holobionts comprise significant biological diversity and biomass in many terrestrial ecosystems (Asplund & Wardle, 2017). Despite their abundance, important ecological function, and broad application as bioindicators (Hawksworth, 1971;Nash & Gries, 2002), the typifications of names for many widespread, important, and threatened taxa remain unsettled. ...
A lectotype is designated for the name of the iconic and well-known macrolichen Ramalina menziesii Taylor from among a suite of largely overlooked syntypes deposited in the Thomas Taylor Herbarium at the Farlow Herbarium, Harvard University. Lectotypes are also selected for the synonyms of R. menziesii: Chlorodictyon foliosum, Ramalina reticulata (≡ Lichen reticulatus Noehd., nom. illeg.) and R. retiformis. The place of publication of L. reticulatus Noehd. is discussed in detail. The case highlights the surprising degree to which the application of names for taxa that have been extensively studied and are widely known outside a narrow specialist field, can remain unresolved.
... Xeric heaths are often dominated by dense mats of the lichen Cladonia stellaris , which can have a negative effect on tree recruitment and growth (Nystuen et al., 2019). Dense mats can reduce the probability of seeds reaching the soil and reduce light availability, which further reduces tree recruitment (Asplund & Wardle, 2017). Lichen coverage can be reduced by increased reindeer densities, which then facilitates tree establishment (Tømmervik et al., 2004). ...
The transition zone between the upper forest boundary and the treeless alpine vegetation (i.e., the treeline ecotone) is expected to shift upward in elevation with global warming. Multiple factors in addition to climate are influencing tree establishment, but it is uncertain to what degree. In this study, we took advantage of a unique dataset with field measurements of mountain birch trees acquired from 32 boreal-alpine treeline ecotone sites situated along a 1100-km latitudinal gradient in Norway to investigate the role of climate, her-bivory, topography, and vegetation on the establishment success of trees. To represent tree establishment, we recorded occurrence, survival, and height growth of short juvenile birch trees (stem height ≤1 m) as response variables at each site in 2008, 2012, and 2018. We used already available climate and herbivory data, and airborne laser scanning (ALS) and unmanned aerial vehicle (UAV) surveyed imagery together with field measurements to compute topography and vegetation explanatory variables per site on microsite scale (approx. 1 m 2). We observed a clear decrease in short juvenile birch tree establishment due to livestock herbivory, evidenced by lower occurrence, reduced survival rate, and diminished height growth in treeline ecotones with higher livestock densities. Winter precipitation and the two land cover classes, tree-covered area and lee side vegetation, were also important for tree establishment. However, the direction and magnitude of the relationships depended on the stage of establishment. While winter precipitation can lead to higher tree occurrence, long-term survival is not necessarily ensured, reflecting diverse requirements for optimal conditions of tree establishment. Thus, our results show that occurrence, survival, and height growth of short juvenile birch trees differ in their requirements to climate, topography, and vegetation, but tree establishment is consistently low with livestock herbivory. Overall, our results suggest that treeline ecotones will shift toward higher elevations in areas with little or no livestock herbivory and close to already established trees and in lee sides. Regarding management and conservation issues, our results
... Although there is a rapidly growing set of studies of lichen functional traits, mirroring advances in other taxa (Gauslaa, 2014;Matos et al., 2015;Ellis et al., 2021;Koch et al., 2022), quantitative functional traits that are more widely applicable (suitable for different thallus morphologies or growth forms) and accessible (that do not require expensive equipment to measure) are still lacking. While easily applied methods have been developed for water storage (water-holding capacity; Asplund and Wardle, 2017), low-cost approaches have not, until now, been proposed in detail for water uptake traits. Furthermore, water storage trait protocols have been focused on large, easily detached taxa, which introduces taxonomic and ecological biases in trait coverage. ...
Premise
Methods to evaluate lichen thalli hydrophobicity have previously been described, but only recently has hydrophobicity been shown to be an important functional trait related to water regulation dynamics that could be used to predict future climate change effects. We describe a novel protocol to measure lichen thallus hydrophobicity that aims to be an easier and more affordable approach.
Methods and Results
Our protocol requires only a micropipette, distilled water, a tripod, and a smartphone or camera. Hydrophobicity is inferred from multiple metrics associated with the absorption times of standardized droplets (initial and total absorption time). We used a data set of 93 lichen taxa with different growth forms and from different biomes and demonstrated that this method is well suited for capturing different levels of hydrophobicity, including very hydrophilic species.
Conclusions
Our results show that this new protocol to measure lichen hydrophobicity is a rapid and low‐cost method to assess an ecophysiologically based functional trait that can be used with almost no limitations, including in different climates, lichen species, and growth forms.
... However, the effects of N deposition on terricolous lichen communities, typical of heathlands, have been largely ignored with only a few studies to date showing that N deposition negatively affects some heathland lichen species (Pilkington et al. 2007;Stevens et al. 2012). This represents a considerable knowledge gap as terricolous lichens provide important ecosystem services including soil stabilization, soil moisture retention, and facilitation of seed germination (Asplund & Wardle 2017). Moreover, few studies have investigated the recovery of lichen communities once disturbance ceased (Edmondson et al. 2013;Benvenutto-Vargas & Ochoa-Hueso 2020). ...
Atmospheric pollution containing soil‐nitrifying ammonium sulfate ((NH₄)₂SO₄) affects semi‐natural ecosystems worldwide. Long‐term additions of (NH₄)₂SO₄ to nitrogen (N)‐limited habitats, including heathlands, increase climate stress affecting recovery from wildfires. Although heathland vegetation largely depends on ericoid mycorrhizal fungi (ErM) to access soil N, we lack detailed understanding of how prolonged exposure to (NH₄)₂SO₄ may alter ErM community composition and host plants' reliance on fungal partners following wildfire and affect recovery. Simulation of atmospheric pollution ((NH₄)₂SO₄) occurred bi‐weekly for 5 years after a 2006 wildfire in a UK heathland. Ten years after treatments ceased, we measured vegetation structure, lichen and lichen photobiont composition, soil characteristics, ErM colonization, ErM diversity in roots and soil, and assessed ErM potential as novel recovery indicators. Heather height and density, and moss groundcover, were greater in N‐enriched plots. Lichen community indices showed significant treatment effects, but without differences in photobionts. Soil pH and Mg were significantly lower in treated plots while soil cation exchange capacity was significantly higher. There were no detectable differences in ErM composition and keystone ErM taxa between control and treated plots. Soil carbon stock measures were variable. Our results indicate atmospheric pollution following fire can have significant lingering effects above‐ and belowground. ErM diversity and root colonization were not assessed in the original N‐addition experiment; we advocate for their inclusion in future studies as an integral part of the recovery assessment toolkit. We show that mycorrhizal fungi diversity is a viable ecological tool and summarize key steps for ErM identification.
... Lichens-obligate symbioses between a fungus and at least one alga or cyanobacterium-are important components of terrestrial ecosystems, regulating substrate moisture, cycling nitrogen, and sequestering carbon (Asplund and Wardle 2017). Many lichen 2 species are also conservation-sensitive and threatened (Allen et al. 2019). ...
... branches or higher parts of a bole. Moreover, typical species from shaded environments, such as leprose and squamulose lichens, are frequent in denser and more preserved forest areas (Asplund & Wardle 2016). ...
Quercus faginea woods in Alvados valley are remnants of ancient forest within a strongly fragmented and diverse human-made matrix. In this contribution, new data concerning lichen diversity characterizing this area are presented, including two species new to Portugal. More than 20% of the species are typical of undisturbed, natural environments confirming these woods to be important areas for preservation of specific lichen flora.
... They can tolerate the most extreme environments on Earth, such as hot deserts and arctic regions, and are characterized by low growth rates and nutrient requirements that enable them to play the role of pioneer vegetation in the colonization of fresh rocks (Chapin, 1980;De Vera, 2012;Raggio et al., 2011). In turn, lichens harbor a diverse community of invertebrates, such as rotifers, tardigrades, mites, springtails, crustaceans and nematodes, and are considered micro-ecosystems that include complex food webs (Asplund & Wardle, 2017). ...
Lichens are symbiotic organisms, usually composed of a fungal partner, the mycobiont, and one or more photosyn-thetic partners, the photobiont, which is most often either a green alga or a cyanobacterium, that harbor a diverse community of invertebrates such as rotifers, tardigrades, mites, springtails, crustaceans, and nematodes. In this work, we isolated the nematode Geraldius galapagoensis (Chambersiellidae) associated with the lichen Hyperphyscia syncolla (Physciaceae) in a region of Buenos Aires Province, Argentina. This species was discovered in a tropical forest of Ecuador and is characterized mainly by a head offset by a constriction from the rest of the body, a esophagus with a cylindrical pharyngeal corpus without a median bulb, a narrow isthmus and an oval basal pharyngeal bulb with strong transverse/butterfly valve apparatus, a tail curved ventrally, ending in dorsally hooked end; the male with seven pairs of latero-ventral pre-anal papillae and three pairs of post-anal in the following positions: one pair latero-ventral and two pairs dorso-lateral and two slightly curved spicules with asym-metric manubrium with an anterior extension. The comparison of the morphometrics of our G. galapagoensis male with that of the original description shows that the body length is shorter, as are the distance of the excretory pore to the anterior end and the tail. On the other hand, the distance from the anterior end to the nerve ring and the esophagus length are greater. The head width, body diameter and spicule length are quite similar. We provide a morphological and morphometrical characterization of a G. galapagoensis second isolate and the first world report of molecular sequences belonging to this species.
... Despite the early recognition of the evolutionary significance of herbivore-plant relationships and the extensive examination of these interactions for more than a century, the ecological associations of animals with other primary producers, such as lichens, have remained largely understudied in an evolutionary framework. Lichens constitute the major life form in ~8% of Earth's terrestrial surface (Ahmadjian 1995), often dominating nutrient-and water-limited environments, such as Arctic and Antarctic ecosystems, littoral zones, and certain types of woodland (Asplund and Wardle 2017). Despite their crucial role in regulating carbon and mineral fluxes, utilization of lichens as a food source appears rather opportunistic in the animal kingdom, given that only sporadic cases of lichenophagous taxa have been reported in the literature. ...
Although the complex evolutionary history of lichen-forming fungi has gained considerable attention, particularly regarding the long-debated role of these organisms in shaping early terrestrial ecosystems, the evolution of lichenivory and its potential impact on the diversification of lichenophages have been largely neglected. With > 800 described species worldwide and a broad geographical distribution, the tribe Helopini (Coleoptera: Tenebrionidae) represents a diverse, yet poorly studied, group of predominantly lichenophagous beetles. Using a dataset of 52 ingroup taxa and five gene fragments, a first phylogenetic hypothesis of the tribe was generated, which was subsequently used for reconstructing the ancestral state of the trophic and habitat associations of the beetles and for estimating a time frame of diversification. Our phylogenetic reconstruction sheds light on the higher-level systematics of the tribe, supporting the current subtribal division of the group while also providing a framework for understanding the intergeneric relationships within subtribes. The results also indicate an Early Cretaceous origin of the tribe, highlighting the close association between Helopini and lichen-forming fungi since the emergence of the group. Nevertheless, at least seven independent switches from lichenophagy to alternative feeding habits have occurred since the middle Eocene, which can be linked temporally to transitions from forests to open habitats.
... Our findings are consistent with those of a previous study that reported the negative effects of Cu on membrane integrity in lichens [41], as well as with broader research indicating the deleterious effects of heavy metal pollution on ecosystems [42]. In addition to its direct impact on lichen health, Cu pollution can have cascading effects at other trophic levels, because lichens serve as an important food source for a variety of organisms [43]. ...
Lichens play crucial roles in the ecosystems, contributing to soil formation and nutrient cycling, and being used in biomonitoring efforts to assess the sustainability of ecosystems including air quality. Previous studies on heavy metal accumulation in lichens have mostly relied on manipulated environments, such as transplanted lichens, leaving us with a dearth of research on how lichens physiologically respond to heavy metal exposure in their natural habitats. To fill this knowledge gap, we investigated lichens from two of South Korea's geographically distant regions, Gangwon Province and Jeju Island, and examined whether difference in ambient heavy metal concentrations could be detected through physiological variables, including chlorophyll damage, lipid oxidation, and protein content. The physiological variables of lichens in response to heavy metals differed according to the collection area: Arsenic exerted a significant impact on chlorophyll degradation and protein content. The degree of fatty acid oxidation in lichens was associated with increased Cu concentrations. Our research highlights the value of lichens as a bioindicator, as we found that even small variations in ambient heavy metal concentrations can be detected in natural lichens. Furthermore, our study sheds light on which physiology variables that can be used as indicators of specific heavy metals, underscoring the potential of lichens for future ecology studies. ARTICLE HISTORY
... Deserts represent arid environments with poor soil nutrients, [2] where vascular plants have low coverage, but biological soil crusts (BSCs) have unique advantages [3]. BSCs cover 70% of arid and semiarid areas, and constitute about 40% of the Earth's terrestrial surface, [4,5] composed of cyanobacteria, algae, lichens, microfungi, bryophytes, [4,6,7] among which lichens play more crucial roles such as promoting nutrient cycling and improving soil physical stability [8,9]. ...
... Even though lichen does not have roots, lichens can take in nutrients such as sulfur and iron from surfaces that are resistant to their growth (Grube et al., 2015). It is possible that lichen thallus Rhizinae can help your body absorb nutrients better (Asplund and Wardle, 2017). It is common for lichens to thrive in environments that are inhospitable to the growth of higher plants, such as places with high quantities of light, high levels of humidity, or high temperatures (Armstrong, 2017). ...
Secondary metabolites are a class of outwardly directed differentiation products of regular cellular metabolism that can operate as chemical messengers across organisms and species. They are molecules largely engaged in the maintenance/homeostasis of the organism. Secondary metabolites influence health-maintenance functions. Utilizing secondary metabolites has proven to be particularly successful in detecting some of the most prevalent food-spoilage fungus, including Penicillium species, Aspergillus species, and Fusarium species. Secondary products are uncommon, low-molecular-weight molecules that are structurally like primary metabolites but have a more restricted distribution than primary metabolites. Lichens are the natural result of a partnership between fungi (the Mycobionts’ partner) and algae (the host of the association). The stability of the secondary metabolites of lichens separates them from other species. Lichens can be both beneficial and hazardous to humans, depending on the location. They assist humanity in numerous ways, including feed and food, medicine, and industrial applications. In France, several lichens are used to make chocolates and pastries, while others are used medicinally. Curry powder made from Parmelia species can be found in Indian cuisine, while Endocarpon miniatum is used as a vegetable in Japan and Evernia prunastri is used to make bread in Egypt. The presence of lichenin, a polysaccharide, in Ramalina fraxinea, R. fastigiata, Evernia prunastri, and Lobaria pulmonaria lichens enables their use as animal feed. Parmelia saxatilis and Parmelia perlata are employed in the treatment of dyspepsia and epilepsy, respectively. Cladonia pyxidata is used to cure whooping cough, Xanthoria parietina is used to treat jaundice, and Pertusaria, Cladonia, and Cetraria are used to treat a variety of conditions. Ochrolechia androgyna and Ochrolechia tartaria are two plants that yield red and purple colors, respectively. Species of Ramalina and Evernia are used to extract the essential oils used to produce cosmetic soap. Some lichens, such as Amphiloma and Cladonia, parasitize mosses and, if left unchecked, can entirely decimate moss colonies. Some secondary compounds produced by lichens, such as anthraquinone pigments, are commonly present in both lichens and free-living fungi. The low levels of bacterial production allow for rapid mutation, selection of resistant strains, and horizontal transmission of resistance genes. Extracts of Usnea ghattensis, Parmotrem pseudotinctorum, Hypogymnia physodes, Lasallia pustulosa, and Parmelia caperata exhibited antioxidant activity. The majority of lichen species are terrestrial, whereas only a handful are found in the ocean
Growing in prominence is the utilization of natural product-based therapies, especially edibles used in traditional medicine, as more people seek natural and holistic approaches to health and well-being. This research aimed to determine the phenolic compounds, and antioxidant, anti-inflammatory, and anticancer effects of aqueous and methanolic extracts from Evernia prunastri (L.) Ach., a common spice in Algeria. HPLC-DAD was used to establish the phenolic profile, whereas the antioxidant activity was determined by DPPH, FRAP, phosphomolybdate, and hydrogen peroxide (H2O2) assays. Human red blood cell (HRBC) stabilization, albumin denaturation, and proteinase inhibition procedures were performed to investigate the anti-inflammatory activities, and an MTT assay was used to demonstrate the cytotoxic effect against three human cancer cell lines (HT-29, PC-3, A549) and human nontumor (CCD18-Co) cells. Our results showed that the major phenolics detected were mostly phenylpropanoids with domination of rosmarinic acid (79.17 mg/g), caffeic acid (46.52 mg/g), trans-cinnamic acid (29.23 mg/g), and chlorogenic acid (23.68 mg/g). In addition, six flavonoids were identified (1.98–11.34 mg/g), namely, luteolin, myricetin, kaempferol, rutin, apigenin, and quercetin. Other compounds were relatively present in both extracts, gallic acid and 3-hydroxybenzoic acid (phenolic acids), except pyrocatechol (benzenediol), which was slightly detected in the aqueous extract (0.91 mg/g). Moreover, both E. prunastri extracts showed strong antioxidant activity, with a higher antioxidant potential, as shown by the methanolic extract. Likewise, both reduced HRBC hemolysis damage and moderately suppressed protein denaturation, which reflected their anti-inflammatory potential. Interestingly, the methanolic extract significantly reduced the growth of HT-29, PC-3, and A549 cells by 67.03, 75.56, and 62.96% respectively. No cytotoxic effects were observed in the nontumor cells. The methanolic extract had the lowest IC50 values of 100 ± 0.04, 146 ± 0.05, and 112 ± 0.06 μg/mL against HT-29, PC-3, and A549 cell lines, respectively. In conclusion, E. prunastri, especially its methanolic extract, could be considered as a promising source of antioxidant and anticancer molecules.
The present study reports 12 lichen taxa from India for the first time. The species are—Agonimia bryophilopsis, Aptrootia elatior, Astrothelium rubrocrystallinum, Bathelium carolinianum, Fulvophyton desertorum, Graphis emersa, Malmidea bacidinoides, M. gyalectoides, Myriotrema classicum, Porina ahlesiana, Pyrenula albothallina, and Trypethelium xanthoplatystomum, collected from Ultapani forest range under Manas Biosphere Reserve, Assam. All the species have been illustrated with detailed taxonomic descriptions.
The great majority of studies on foundation species focused on a single dominant plant in a community, while more than one such species can often coexist and compete for space and limited resources. Morphologically different coexisting foundation species can create diverse niches occupied by different subsets of beneficiary species. To test this hypothesis, we sampled alpine plant communities at exposed fellfields in alpine zone, in the Taisetsu Mountains (Hokkaido, northern Japan), with coexisting putative foundation species Pinus pumila (evergreen shrub) and Diapensia lapponica (evergreen cushion-forming shrub), and analyzed their spatial relationships with other plants. Preliminary vegetation survey indicated that fruticose lichens and Loiseleuria procumbens (evergreen mat-forming shrub) might also act as a foundation species; thus, we included them in our analyses. The coexisting foundation species had both general as well as specific effects on plant community structure. Namely, almost all the members of the community aggregated spatially with lichens, while the other foundation species were spatially segregated from each other. These foundation plants associated with different members of the community, thus showing species-specific effects on the community structure. Blooming species showed even stronger patterns of species-specific spatial associations, suggesting that foundation species had beneficial effects on their associated species. We conclude that the focus on coexisting foundation species can reveal important details of community structure which would be hidden if we treated all species as equal members of the community. Studying the effects of coexist-ing foundation species could greatly advance our understanding of how species diversity functions in plant communities. K E Y W O R D S community structure, ecosystem engineer, niche construction, plant biodiversity, spatial patterns
В работе предложен и апробирован новый подход оптимизации биотехнологических процессов, в том числе процесса микроклонального размножения. Предлагаемый метод основан на построении карты подобия структур молекул вторичных метаболитов растительных экстрактов и молекул – регуляторов процессов морфогенеза растений (прежде всего фитогормонов) с последующим прогнозированием действия экстракта. В качестве примера был использован экстракт лишайника Cetraria islandica (L.) Ach. (Parmeliacea), для которого хорошо известен спектр содержащихся вторичных метаболитов. Выявлено структурное сходство алифатических вторичных соединений лишайника (протолихестериновая и лихестериновая кислоты) со стриголактонами (в большей степени), а также с гиббереллинами и брассиностероидами. На основе анализа полученных результатов был сделан прогноз о дозозависимом воздействии экстракта лишайника C. islandica на ростовые процессы и ризогенез микропобегов in vitro . Эта гипотеза была экспериментально проверена в экспериментах при микроклональном размножении высших растений Lonicera caerulea L. и Populus tremula L. В результате проведенных работ установлено, что добавление экстракта из C. islandica в концентрации 10–50 мг/л в состав питательной среды увеличивало коэффициент размножения L. caerulea (на 31%) и P. tremula (на 8%).Экспериментально доказана ризогенная активность экстракта лишайника в тех же концентрациях (10–50 мг/л среды), схожая с активностью стриголактонов и гиббереллинов. Также показано положительное влияние экстракта C. islandica (50 мг/л) на элонгацию микропобегов обеих культур и геммогенез P. tremula . Предложенный подход позволяет оптимизировать исследования, направленные на выявление эффекта различных экстрактов на морфогенез растений in vitro путем предварительного построения карты подобия содержащихся в экстрактах вторичных метаболитов (в том числе по данным литературы) и известных регуляторов роста (в том числе фитогормонов) с последующим прогнозированием действия экстракта.
Anthropogenic disturbance is rapidly increasing through habitat degradation, development, and deforestation. Gaps remain in understanding the effects of this disturbance on diverse and ecologically important organisms such as lichens. In North America, studies have focused on epiphytic macrolichens and catastrophic disturbance, largely ignoring microlichens and less severe disturbances. The Intermediate Disturbance Hypothesis predicts these moderate disturbances will lead to higher species richness. Here we examine the effects of anthropogenic disturbance in the form of land management on overall lichen richness, including microlichens, and on the species richness of eight lichen functional groups. The study draws on a comprehensive data set of 872 species, in 208 one-hectare plots throughout the Southern Appalachian Mountains, a global biodiversity hotspot in eastern North America. A habitat quality index based on an established forestry metric was used as a proxy for anthropogenic disturbance and was quantified using a 10-part score including categories such as percent native tree canopy cover and degree of fragmentation. Linear models were used to compare habitat quality scores to overall species richness and to species richness of functional groups. Rather than following the Intermediate Disturbance Hypothesis, all groups uniformly follow a negative linear relationship: as disturbance increases, species richness decreases. This pattern held even for widely variable functional groups such as morphotype. Effective conservation of lichen richness should prioritize the maintenance of existing older, less-disturbed stands within large, contiguously forested areas.
Lichenized fungi initiate their symbiotic structures from microscopic stages after recognition of compatible algae. The partnerships ultimately emerge as complex macroscopic phenotypes which are unrivaled in the fungal kingdom by their resilience and durability. This chapter presents an overview of lichen symbioses and covers the morphology and systematics of the fungal phenotypes, as well as their associations with diverse photobionts. This is followed by a coarse overview of ecophysiology and the secondary chemistry. A special focus is given to the diversity of and the interactions with additional microorganisms. Finally, a few comments on the effects of pollution and environmental change point to the usefulness of lichens as bioindicators.
Relatório da biodiversidade em pinhal.
The flora of Armenia comprises about 3800 species of vascular plants (The fifth national report to convention on biological diversity. Yerevan, 2014). A characteristic feature of the flora is the absolute predominance of both the number of species and genera of angiosperms – about 97%. Club mosses, horsetails, and ferns are represented by 39 species, and gymnosperms, only nine species. Among angiosperms, dicots completely predominate – about 80% species. Algae are an integral component of aquatic and terrestrial ecosystems. They carry out the process of converting solar energy into the chemical energy of photosynthesis products, which is necessary to maintain life and the circulation of substances and energy in the biosphere of our planet, and create an energy base for the existence of organisms of other trophic levels. Currently, the algoflora of Armenia contains 497 species of land and water algae, which are included in 131 genera. Lichens are composite organisms traditionally known as an association of fungus and algae and/or cyanobacteria. According to the latest lichenological studies, 619 lichenized fungi taxa have been reported from the Republic of Armenia so far. Over the years, studies of the bryoflora of Armenia documented 433 species of mosses belonging to 168 genera and 65 families. Of these, 50 species (28 genera, 20 families) are from liverworts, and 383 species (140 genera, 45 families), from mosses (Manakyan, Resultaty bryologicheskikh issledovanij v Armenii (Results of bryological studies in Armenia). Arctoa 5:15–33, 1995; Manakyan et al., Materialy k Hepaticae Armenii (Materials to Hepaticae of Armenia). Flora, vegetation and plant resources of Armenia, 12, 17–25, 1999; Pogosyan, Bryoflora vulkanicheskogo massiva Arailer (Bryoflora of volcanic massif Arailer) (Republic of Armenia). Arctoa 12:187–190, 2003b).
A meta-analysis of literature data with statistical analysis concerning the effect of lichen substances on the inhibition of 10 yeast species (Candida albicans, C. dubliniensis, C. glabrata, C. parapsilosis, C. sake, C. tropicalis, Colacogloea diffluens, Cryptococcus neoformans, Issatchenkia orientalis and Saccharomyces cerevisiae) is provided. Lichen extracts were obtained using 16 solvents from 100 epiphytic, 51 epigeic and 37 epilithic lichen species. The most studied lichen taxa at the generic level belonged to the family Parmeliaceae. 67 individual secondary metabolites belonging to 12 biochemical classes were subjected to experiments. The MIC was used most frequently. Candida albicans was the most commonly tested species; other fungal species remain relatively less or very poorly tested. Against C. albicans, a stronger antifungal potential is demonstrated by extracts from numerous lichen species, including Evernia prunastri, Hypotrachyna vexans, Pseudevernia furfur-acea, Ramalina pollinaria, R. polymorpha, Cladonia foliacea, C. pocillum, C. rangiformis and Umbilicaria cylin-drica, which generated secondary compounds such as atranorin, a-collatolic acid, ethyl everninate, lecanoric acid, methyl 2,6-dihydroxy-4-methylbenzoate, protolichesterinic acid, retigeric acid A and B, scrobiculin and usnic acid. The potential of the extracts and secondary metabolites makes it possible to replace several commercial antibiotics in the future, in particular clotrimazole and fenticonazole. For the purpose of future experiments, this review stresses the need to standardizse research methodology, especially for the simultaneous determination of MIC and IZ and, if possible, MFC. There is a need for greater use of water as a solvent to extract lichen substances as a safe and feasible method for phytopharmaceutical and cosmetic purposes. The conclusions drawn highlight the prospective use of lichen extracts and secondary metabolites against yeast in the medical, phytopharmaceutical and cosmetic fields and as preservatives.
Lichens are generally considered as mutualisms between fungi and green algae or cyanobacteria. These partnerships allow light-exposed and long-living joint structures. The unique organization of lichens provides still unexplored environments for microbial communities. To study lichen-associated bacterial communities, we analyze samples, by a polyphasic approach, from three lichen species (Cladonia arbuscula, Lecanora polytropa and Umbilicaria cylindrica) from alpine environments. Our results indicate that bacteria can form highly structured, biofilm-like assemblages on fungal surfaces and reach considerable abundances of up to 10(8) cells per gram fresh weight. Fluorescence in situ hybridization reveals the predominance of Alphaproteobacteria. Microbial fingerprints performed by PCR-single-strand conformation polymorphism analysis using universal and group-specific primers show distinct patterns for each lichen species. Characterization of cultivable strains and presence of functional genes in the total fraction suggest the involvement of associated bacteria in nutrient cycling. Ubiquitous nifH genes, which encode the nitrogenase reductase, show a high diversity and are assigned to Alphaproteobacteria and Firmicutes, for example, Paenibacillus. Cultivable strains mainly belonging to the genera Acinetobacter, Bacillus, Burkholderia, Methylobacterium and Paenibacillus show lytic (chitinolytic, glucanolytic, and proteolytic) activities, hormone production (indole-3-acetic acid) as well as phosphate mobilization and antagonistic activity toward other microorganisms. The traditional concept of lichens has to be expanded to consider multiple bacterial partners.
128 species in 45 genera of sorediate and isidiate, crustose, corticolous lichens are recorded from Norway. Accounts of their morphology, chemistry, and substratum preferences are presented, and a discussion of their distribution in Norway is supported by maps for a number of taxa. With few exceptions, the taxa can be distinguished on thallus characters alone. Several taxa, especially those with brown or blue-pigmented soralia, have soredia with a distinct cortex. New species are: Buellia arborea Coppins & Tønsb. (from Norway and Scotland), Fuscidea arboricola Coppins & Tønsb. (from Norway, Sweden, and Scotland), F. pusilla Tønsb. (from Norway, Sweden, and Scotland), Lecanora flavoleprosa Tønsb. (from Norway and Austria), L. flavopunctata Tønsb. (from Norway and Sweden), L. norvegica Tønsb. (from Norway), Lecidea gyrophorica Tønsb. (syn. L. epizanthoidiza auct., non Nyl.), L. praetermissa Tønsb. (from Norway and Sweden), L. subcinnabarina Tønsb. (from Norway), L. vacciniicola Tønsb. (from Norway, Sweden, and Spain), Lecidella subviridis Tønsb. (from Norway and Sweden), Lepraria elobata Tønsb. (from Norway), L. jackii Tønsb. (from Norway), L. obtusatica Tønsb. (from Norway), L. umbricola Tønsb. (from Norway, England, and Scotland), Micarea coppinsii Tønsb. (from Norway and Scotland), Rinodinaflavosoralifera Tønsb. (from Norway), R. disjuncta Sheard & Tønsb. (from Norway and the pacific coast of U.S.A. and Canada), and Schaereria corticola Muhr & Tønsb. (from Norway, Sweden and Scotland). Ochrolechia androgyna s. lat. is shown to comprise at least four distinct species.
New combinations are: Cliostomum leprosum (Räsänen) Holien & Tønsb., Lepraria rigidula (B. de Lesd.) Tønsb., Mycoblastus caesius (Coppins & P. James) Tønsb., Placynthiella dasaea (Stirton) Tønsb., and Ropalospora viridis (Tønsb.) Tønsb. Lecidea turgidula var. pulveracea Fr. is raised to specific level with the new name Lecidea leprarioides Tønsb. Mycoblastus sterilis Coppins & P. James is reduced to synonymy with M. fucatus Stirton.
Pertusaria borealis is new to Europe. Halecania viridescens, Lecanora farinaria, Lepraria caesioalba Laundon ined., L. eburnea Laundon ined., Megalospora tuberculosa, Opegrapha multipuncta, and Scoliciosporum gallurae are new to Scandinavia. Mycoblastus caesius, Lecidella elaeochroma “f. soralifera”, L. flavosorediata, Micarea granulans (saxicolous, not treated), Opegrapha sorediifera, and Rinodina degeliana are new to Norway.
In some cases, Poelt’s species pair concept can be applied to this group of lichens. Additional secondary substances, not occurring in the primary species, sometimes occur in the soralia of the secondary species. In this case, presence of the additional substance cannot be regarded as an independent taxonomic character, and the species pair concept is still useful. However, morphologically indistinguishable specimens with different chemistry may represent different secondary species.
The term consoredia is introduced to denote diaspores composed of aggregated soredia.
Lichens are hosts for a variety of lichenicolous fungi. By investigating two lichens with specialized parasites, we will test the hypothesis that these parasites reduce lichen fitness by increasing the palatability of their respective hosts.
The palatability of Lobarina scrobiculata and Lobaria pulmonaria with or without galls of the lichenicolous fungi, Plectocarpon scrobiculatae and P. lichenum , respectively, were quantified in a feeding‐preference experiment with grazing snails ( Cepaea hortensis ). We repeated the experiment for pairs with or without gall in which the carbon‐based secondary compounds ( CBSC s) had been reduced nondestructively by acetone rinsing.
Lichens with galls had lower concentration of CBSC s than those without, but this contrast disappeared after acetone rinsing. In the lichen high in nitrogen (N) (the cyanolichen L. scrobiculata ), the grazing was low, and the snails did not discriminate between specimens with and without Plectocarpon‐ galls. In L. pulmonaria low in N (green algae as main photobiont), the parasite reduced the lichen C : N ratio and the snails strongly preferred specimens with Plectocarpon‐ galls, regardless of whether CBSC concentration had been reduced or not.
In conclusion, some lichen parasites can indirectly reduce lichen fitness by increasing its palatability and thus the grazing pressure from snails, whereas other parasites do not affect grazing preferences.
Background and aims
Functional traits are increasingly being used to assess the degree to which ecosystems maintain key processes. The functional traits of vascular plants are well-documented but those of non-vascular plants are poorly known. We describe a comprehensive methodology to measure the functional traits of soil-borne lichens, mosses and liverworts making up biocrust (biological soil crust) communities.
Methods
We collected 40 biocrust taxa from across 10,000 km2 of eastern Australia, and measured eight functional traits using a combination of mensurative studies and laboratory-based experiments. These traits were sediment capture, absorptivity, root (or rhizine) length, height, and the activity of four enzymes involved in key nutrient cycles; β-glucosidase, β-D-cellobiosidase, N-acetyl-β-glucosaminidase and phosphatase.
Results
Taxa were distributed across a broad range of trait values. Sediment capture values ranged from 2 % in the crustose lichen Diploschistes thunbergianus to 83 % in the tall moss Triquetrella papillata. The highest absorptivity value was observed in the moss Bartramia hampeana ssp. hampei, which was able to absorb 12.9 times its dry mass in water, while the lowest value, 0.3, was observed in Diploschistes thunbergianus. Multivariate analyses revealed that biocrust morphological groups differed significantly in their functional profiles.
Conclusions
Our results indicate that biocrust taxa vary greatly in their functional traits and that morphological groups explain, in part, the ability of biocrusts to sequester resources (sediment, moisture) and to undertake key processes associated with the cycling of carbon, nitrogen and phosphorus. This methodology will enhance our understanding of ecosystem functioning in drylands where biocrusts make up a large component of the surface cover and provide a range of ecosystem goods and services.
Lichens are commonly recognized as a symbiotic association of a fungus and a chlorophyll containing partner, either green algae or cyanobacteria, or both. The fungus provides a suitable habitat for the partner, which provides photosynthetically fixed carbon as energy source for the system. The evolutionary result of the self-sustaining partnership is a unique joint structure, the lichen thallus, which is indispensable for fungal sexual reproduction. The classical view of a dual symbiosis has been challenged by recent microbiome research, which revealed host-specific bacterial microbiomes. The recent results about bacterial associations with lichens symbioses corroborate their notion as a multi-species symbiosis. Multi-omics approaches have provided evidence for functional contribution by the bacterial microbiome to the entire lichen meta-organism while various abiotic and biotic factors can additionally influence the bacterial community structure. Results of current research also suggest that neighboring ecological niches influence the composition of the lichen bacterial microbiome. Specificity and functions are here reviewed based on these recent findings, converging to a holistic view of bacterial roles in lichens. Finally we propose that the lichen thallus has also evolved to function as a smart harvester of bacterial symbionts. We suggest that lichens represent an ideal model to study multi-species symbiosis, using the recently available omics tools and other cutting edge methods.
Biocrusts play crucial roles in hydrological processes by controlling soil water availability and regulating water redistribution from source to sink areas. Most studies have examined the influence of biocrusts on isolated components of the soil water balance, but few have addressed this matter from an integrated point of view, involving their influence on all components together. Such integration is crucial to elucidate the overall effects of biocrusts on the soil water balance. The aim of this study was to review the role of biocrusts in the soil water balance, by examining their influence on infiltration, evaporation and soil moisture at plot scale, in two contrasting ecosystems of SE Spain. Our results show that biocrust infiltration was higher in flat soils with sandy loam texture than in steep soils with silty loam texture. The influence of biocrusts on infiltration depended on rainfall intensity. Biocrusts increased infiltration with respect to biocrust-removed soils during low intensity rainfalls but showed similar or even lower infiltration than biocrust-removed soils during high-intensity events. As a result of the increase in infiltration and a decrease in evaporation during wet cold periods, biocrusts increased soil moisture when compared with biocrust-removed soils. However, during warm periods, biocrusts and biocrust-removed soils lost water very quickly, thus resulting in similar water losses and moisture content under both types of surfaces. We conclude that biocrusts increase water input by increasing infiltration and soil moisture, and reduce water output by reducing soil evaporation, thus eventually enhancing the available water to plants.
We investigated how lichen carbon-based secondary compounds (CBSCs) affect abundance of invertebrates in five lichen species growing on the forest floor (. Cladonia rangiferina, Cladonia stellaris) or on tree trunks (. Evernia prunastri, Hypogymnia physodes, Pseudevernia furfuracea). To do this, CBSCs were removed by rinsing lichen thalli in acetone (which has no adverse effects on the lichens) and the lichens were re-transplanted in their natural habitat. After 4 months there was higher abundance of mites, springtails and spiders in the three epiphytic lichens that had their CBSC concentrations reduced. The increase in predatory spiders following CBSC reduction suggests that the compounds have multitrophic consequences. The acetone treatment reduced the number of nematodes in four of the lichen species. Given that lichens serve as important habitats for a diverse range of invertebrates, increased knowledge of how lichen CBSCs may regulate their abundance helps us to better understand the role that lichens and their defence compounds play in structuring forest food webs.
Recent studies have shown that accounting for intraspecific trait variation (ITV) may better address major questions in community ecology. However, a general picture of the relative extent of ITV compared to interspecific trait variation in plant communities is still missing. Here, we conducted a meta-analysis of the relative extent of ITV within and among plant communities worldwide, using a data set encompassing 629 communities (plots) and 36 functional traits. Overall, ITV accounted for 25% of the total trait variation within communities and 32% of the total trait variation among communities on average. The relative extent of ITV tended to be greater for whole-plant (e.g. plant height) vs. organ-level traits and for leaf chemical (e.g. leaf N and P concentration) vs. leaf morphological (e.g. leaf area and thickness) traits. The relative amount of ITV decreased with increasing species richness and spatial extent, but did not vary with plant growth form or climate. These results highlight global patterns in the relative importance of ITV in plant communities, providing practical guidelines for when researchers should include ITV in trait-based community and ecosystem studies.
Significance
In drylands worldwide, where plant cover is sparse, large amounts of the ground surface are covered by specialized organisms that form biological soil crusts (biocrusts). Biocrusts fix carbon and nitrogen, stabilize soils, and influence hydrology. Extensive physical disturbance from livestock/human trampling and off-road vehicles is known to destroy biocrusts and alter ecosystem function. More recent work also indicates that climate change can affect biocrust communities. Contrary to our expectations, experimental climate change and physical disturbance had strikingly similar impacts on biocrust communities, with both promoting a shift to degraded, early successional states. These results herald ecological state transitions in drylands as temperatures rise, calling for management strategies that consider risks from both physical disturbances and climate change.
Soil communities dominated by lichens and mosses (biocrusts) play key roles in maintaining ecosystem structure and functioning in drylands worldwide. However, few studies have explicitly evaluated how climate change-induced impacts on biocrusts affect associated soil microbial communities. We report results from a field experiment conducted in a semiarid Pinus halepensis plantation, where we setup an experiment with two factors: cover of biocrusts (low [<15%] versus high [>50%]), and warming (control versus a ∼2°C temperature increase). Warming reduced the richness and cover (∼45%) of high biocrust cover areas 53 months after the onset of the experiment. This treatment did not change the ratios between the major microbial groups, as measured by phospholipid fatty acid analysis. Warming increased the physiological stress of the Gram negative bacterial community, as indicated by the cy17:0/16:1ω7 ratio. This response was modulated by the initial biocrust cover, as the increase in this ratio with warming was higher in areas with low cover. Our findings suggest that biocrusts can slow down the negative effects of warming on the physiological status of the Gram negative bacterial community. However, as warming will likely reduce the cover and diversity of biocrusts, these positive effects will be reduced under climate change.
The lichen Hypogymnia physodes was sampled from spruce trunks and we used to assess natural elements in the throughfall from pairs of neighbouring beech (Fagus sylvatica) and spruce (Picea abies) canopies in an unmanaged forest reserve. The beech bark (pH = 4.36 ± 0.13) was less acidic than spruce bark (3.71 ± 0.06). After a 1 yr transplantation onto trunks, lichens on beech had significantly higher concentrations of Ca, K, Mg and P than on spruce, and lower Mn, Zn and C, but had similar Al, B, Fe, N, Na, S and Si concentrations. Base cations (Ca, Mg, K) in lichens highly significantly increased with bark pH, with no overlap between tree species neither for base cations, nor for pH. The results are consistent with the view that trees modify the elemental composition of lichens in their dripzone, and that trees at least to some extent can modify the elemental chemistry of their local surroundings and thus influence ecosystem processes. We discuss lichen transplantation as a method to estimate long-term effects of tree species on local chemical environments.
Lichens are symbiotic organisms in which fungi and algae and/or cyanobacteria form an intimate biological union. This diverse group is found in almost all terrestrial habitats from the tropics to polar regions. In this second edition, four completely new chapters cover recent developments in the study of these fascinating organisms, including lichen genetics and sexual reproduction, stress physiology and symbiosis, and the carbon economy and environmental role of lichens. The whole text has been fully updated, with chapters covering anatomical, morphological and developmental aspects; the contribution of the unique secondary metabolites produced by lichens to medicine and the pharmaceutical industry; patterns of lichen photosynthesis and respiration in relation to different environmental conditions; the role of lichens in nitrogen fixation and mineral cycling; and the use of lichens as indicators of air pollution. This is a valuable reference for both students and researchers interested in lichenology.
Exposure to high light induced a quantitatively similar decrease in the rate of photosynthesis at limiting photon flux density (PFD) and of photosystem II (PSII) photochemical efficiency, FV/FM, in both green and blue-green algal lichens which were fully hydrated. Such depressions in the efficiency of photochemical energy conversion were generally reversible in green algal lichens but rather sustained in blue-green algal lichens. This greater susceptibility of blue-green algal lichens to sustained photoinhibition was not related to differences in the capacity to utilize light in photosynthesis, since the light-and CO2-saturated rates of photosynthetic O2 evolution were similar in the two groups. These reductions of PSII photochemical efficiency were, however, largely prevented in lichen thalli which were fully desiccated prior to exposure to high PFD. Thalli of green algal lichens which were allowed to desiccate during the exposure to high light exhibited similar recovery kinetics to those which were kept fully hydrated, whereas bluegreen algal lichens which became desiccated during a similar exposure exhibited greatly accelerated recovery compared to those which were kept fully hydrated. Thus, green algal lichens were able to recover from exposure to excessive PFDs when thalli were in either the hydrated or desiccated state during such an exposure, whereas in blue-green algal lichens the decrease in photochemical efficiency was reversible in thalli illuminated in the desiccated state but rather sustained subsequent to illumination of thalli in the hydrated state.
This handbook is an indispensable tool for the isolation, identification and structural analysis of the approx. 700 substances currently known to occur in lichens. The first part covers all necessary methods for the analysis of lichen metabolites; the second part gives the analytical and spectroscopical data of all known lichen substances as well as a key to their identification and differentiation.
Besides its high value for all chemists working with these substances as a basis for other products, the book serves as a chemotaxonomical key to the identification of lichen species and as a reference for all those who use lichens for the biomonitoring of environmental pollution.
Relative growth rates (RGR) and carbon-based secondary compounds (CBSCs) were quantified in four dominant terricolous arctic-alpine mat-forming lichens with different preferences for snow cover. The aim was to evaluate the effects of snow depth, and thus snow cover duration, on lichen growth and performance. The species,
Alectoria ochroleuca
,
Flavocetraria nivalis
,
Cladonia mitis
and
Cetrariella delisei
, are associated with increasing snow depth, respectively. They were transplanted for one year at five snow depths (0, 60, 120, 160 and 200 cm measured in early May) along each of four natural ridge to snow bed gradient transects in oceanic-alpine sites (western Norway). Snow slightly thicker than in source habitats caused negative RGR in the ridge top-dependent
A. ochroleuca
and the co-occurring
F. nivalis
with somewhat higher snow tolerance. Only
C. mitis
with the broadest ecological niche had positive RGR along most of the gradients (0–160 cm), even outside its natural range. The most snow-tolerant species,
C. delisei
, tolerant also to temporal inundation in water, had the lowest RGR. Nevertheless, it performed as well in places with little or no snow as in places where it grows naturally. Snow depth significantly affected total concentrations of CBSCs mainly in
A. ochroleuca
, which experienced substantial mass loss under snow. There was a highly significant increase in usnic acid concentration with increasing mass loss in
A. ochroleuca
, probably because usnic acid decays more slowly than other components. In conclusion, snow reduced lichen RGR, but in species-specific ways. Therefore, increasing snow depth
per se
along spatial and/or temporal scales likely reduces abundance and distribution of dominant mat-forming lichens in the alpine ecosystems of Scandinavia.
Alpine vascular plants seem to use other strategies in surviving a cold environment than reducing the reflectance in level leaves. Pubescence in alpine plants has small effect upon total reflectance, but may increase the amount of photosynthetic active radiation within the sheltered canopy. Alpine cushion plants like Silene acaulis, Diapensia lapponica and Loiseleuria procumbens maximize absorptance of radiant energy with minimum heat losses, probably as an effect of the dense canopy structure. The young inflorescences of Eriophorum vaginatum were extremely efficient absorbators, while the reflectance in Salix catkins was close to that of green leaves. In lichens, a great variation both in visible (400-700 nm) and infrared (700-1400 nm) reflectance was found. Factors involved in limiting the downward distribution of alpine plants are discussed. Some species avoid lowlands since they are drought sensitive (low cuticular diffusion resistance), others, mainly cushion plants with low heat exchange capacity, are probably overheated in lowlands.-from Author
Corticolous microarthropod communities were analyzed in 3 sites located in Belgian Lorraine and related to their microhabitat (epiphytic cover), to phorophytes and sites. Although Collembola represent c38% of the corticolous Arthropoda, only 24 species were recorded. At the population level, 7 common species were studied in relation to seasons and habitats. At the community level, collembolan taxocenoses are compared to the community classification obtained by studying Arthropoda as a whole; they turn out to be a poor indicator of the structure and composition of corticolous microcenoses. -from Author
Using scanning electron microscopy, it was demonstrated that moth larvae consumed upper cortex and algal layers of the lichen Cladonia pocillum, but not the medulla. Feeding usually occurred on primary squamules leaving podetia intact. Decrease in the algal complement of squamules was confirmed by significantly lower chlorophyll a, chlorophyll b, and total carotenoids. Decreased Fv/Fm in consumed squamules showed that the status of photosystem II was also altered. However chlorophyll a/b and the integrity of chlorophyll a were not changed significantly. Respiration, as indicated by dehydrogenase activity of the mycobiont hyphae in medulla, was not changed by feeding. The presence of fumarprotocetaric acid in the medulla was confirmed using TLC. Although fumarprotocetraric acid is considered an antiherbivore compound, it does not provide total protection for C. pocillum, as it is located only in medullar hyphae.
Several studies have proposed that lichens in the spruce-lichen woodlands of the northern section of the Canadian Boreal Region inhibit seed germination and seedling recruitment and even reduce tree growth. In fact, these inhibitory effects of the lichen mat may partly explain the dynamics and spatial structure of the spruce-lichen woodlands. In this study, we followed white spruce seedling establishment on control surfaces and on surfaces on which lichens had been removed in a spruce-lichen woodland in northwest Québec. We also removed lichens around white spruce juveniles of three size classes and monitored their growth over a 5-year period. Lichen-removal increased white spruce seedling establishment but reduced growth, particularly in juveniles > 20 cm in height. These results show that there is a shift from negative to positive in the effects of the lichen mat on white spruce early after the seedling establishment phase.
Lichens are symbiotic organisms in which fungi and algae and/or cyanobacteria form an intimate biological union. This diverse group is found in almost all terrestrial habitats from the tropics to polar regions. In this second edition, four completely new chapters cover recent developments in the study of these fascinating organisms, including lichen genetics and sexual reproduction, stress physiology and symbiosis, and the carbon economy and environmental role of lichens. The whole text has been fully updated, with chapters covering anatomical, morphological and developmental aspects; the contribution of the unique secondary metabolites produced by lichens to medicine and the pharmaceutical industry; patterns of lichen photosynthesis and respiration in relation to different environmental conditions; the role of lichens in nitrogen fixation and mineral cycling; and the use of lichens as indicators of air pollution. This is a valuable reference for both students and researchers interested in lichenology.
The management of wild or tame reindeer must be partly based on household studies of the pastures. This is also true for other ungulates, and studies on feeding behavior have been numerous. A review of the literature may be found in Golley and Buechner (1968) or Petrusewicz and MacFadyen (1970).
The experiments reported here were designed to study the effect of usnic acid on sunflower and maize plantlets.Plants were grown under controlled conditions and usnic acid (5 · 10-5 M) was added via the transpiration stream during 1 photoperiod.In the two species, a decrease in water loss (40%) was observed without significant reduction of CO2-uptake in sunflower.We conclude that the decline of the transpiration rate was caused by a partial stomatal closure.The effect of a 24 h treatment was reversed in 4–5 days.Usnic acid induced morphological modifications such as dwarfism and modification of root system.These results are discussed in the light of a possible utilization of usnic acid as antitranspirant.Likelihood of a transport of usnic acid itself to the action sites is discussed.
Lichens are symbiotic organisms in which fungi and algae and/or cyanobacteria form an intimate biological union. This diverse group is found in almost all terrestrial habitats from the tropics to polar regions. In this second edition, four completely new chapters cover recent developments in the study of these fascinating organisms, including lichen genetics and sexual reproduction, stress physiology and symbiosis, and the carbon economy and environmental role of lichens. The whole text has been fully updated, with chapters covering anatomical, morphological and developmental aspects; the contribution of the unique secondary metabolites produced by lichens to medicine and the pharmaceutical industry; patterns of lichen photosynthesis and respiration in relation to different environmental conditions; the role of lichens in nitrogen fixation and mineral cycling; and the use of lichens as indicators of air pollution. This is a valuable reference for both students and researchers interested in lichenology.
Hair lichens (Alectoria, Bryoria, Usnea) with high surface-area-to-mass ratios rapidly trap moisture. By photography and scanning we examined how internal water storage depended on morphological traits in five species. Specific thallus mass (STM, mg DM cm-2) and water holding capacity (WHC, mg H2O cm-2) after shaking and blotting a fully hydrated thallus increased with thallus area. STM was ≈50% higher in Alectoria and Usnea thalli than in Bryoria. WHC was highest in Alectoria while percent water content of freshly blotted thalli was lowest in Usnea. Thallus area overlap ratio (TAO), assessing branch density of the thallus, was highest in the two thinnest Bryoria; lower in the thicker Usnea. Within species, hair lichens increased their water storage by increasing branch density rather than branch diameter. The taxonomically related genera Alectoria and Bryoria shared water storage characteristics, and differed from Usnea. Hair lichens in lower canopies have among the lowest water storage capacity reported in lichens.
Acetone can extract secondary compounds from many air-dry lichens without affecting their viability. More polar solvents were highly detrimental to photosystem II (PSII), whereas less polar solvents failed to extract the compounds. Acetone tolerance, assessed by chlorophyll fluorescence after a 48 hrs recovery subsequent to the acetone submersion, varied between the 12 studied species. Peltigera aphthosa suffered already after 30 minutes, whereas the vitality of Lasallia pustulata did not Start to decline until after 250 hrs submersion. Lichens with Coccomyxa, Dictyochloropsis and Nostoc photobionts were more acetone-susceptible than the five tested Trebouxia lichens. Whereas secondary compounds could be completely extracted within <1 hr in Xanthoria parietina, a 200 hrs extraction was needed for L. pustulata and Xanthoparmelia conspersa. Secondary compounds of P. aphthosa, Nephroma arcticum and Lobaria pulmonaria could not be extracted before the viability was severely affected. Accordingly, Trebouxia lichens appeared to be most suited for testing ecological and physiological roles of Secondary compounds.
Lichens are useful monitoring organisms for heavy metal pollution. They are high in carbon based secondary compounds (CBSCs) among which some may chelate heavy metals and thus increase metal accumulation. This study quantifies CBSCs in four epiphytic lichens transplanted for 6months on stands along transects from a highway in southern Norway to search for relationships between concentrations of heavy metals and CBSCs along a gradient in heavy metal pollutants. Viability parameters and concentrations of 21 elements including nutrients and heavy metals in these lichen samples were reported in a separate paper. Medullary CBSCs in fruticose lichens (Ramalina farinacea, Usnea dasypoga) were reduced in the most polluted sites, but not in foliose ones (Parmelia sulcata, Lobaria pulmonaria), whereas cortical CBSC did not change with distance from the road in any species. Strong positive correlations only occurred between the major medullary compound stictic acid present in L. pulmonaria and most heavy metals, consistent with a chelating role of stictic acid, but not of other studied CBSCs or in other species. However, heavy metal chelating did not protect L. pulmonaria against damage because this species experienced the strongest reduction in viability in the polluted sites. CBSCs with an accumulation potential for heavy metals should be quantified in lichen biomonitoring studies of heavy metals because they, like stictic acid, could overshadow pollutant inputs in some species rendering biomonitoring data less useful. In the two fruticose lichen species, CBSCs decreased with increasing heavy metal concentration, probably because heavy metal exposure impaired secondary metabolism. Thus, we found no support for a heavy metal protection role of any CBSCs in studied epiphytic lichens. No intraspecific relationships occurred between CBSCs versus N or C/N-ratio. Interspecifically, medullary CBSCs decreased and cortical CBSCs increased with increasing C/N-ratio.