Lobaria Pulmonaria Research Articles

The lichens of forest rocky communities of the hill Muroigora (Arkhangelsk Region, Northwest Russia)

The present study reports 188 species and 2 subspecies of lichens and allied fungi from forest rocky communities of the hill Muroigora situated in the Arkhangelsk part of the National park “Vodlozersky” (Arkhangelsk Region, NW Russia). Lepraria ecorticata is new to Russia, and 13 more species are new for the mainland area of the Arkhangelsk Region: Arthonia mediella, Arthonia vinosa, Bacidia igniarii, Bryoria vrangiana, Chaenothecopsis pusiola, Cladonia caespiticia, Lecidea plana, Lepraria borealis, Micarea misella, Pertusaria pustulata, Schaereria cinereorufa, Xanthoparmelia pulla and Xylographa trunciseda. Two lichen species, Bryoria fremontii and Lobaria pulmonaria, are in the Red Data Books of the Arkhangelsk Region and Russian Federation. A total of 89 species are reported as new for the Vodlozersky National Park.

Emissions of carotenoid cleavage products upon heat shock and mechanical wounding from a foliose lichen

Carotenoids constitute a major target of chloroplastic photooxidative reactions, leading to the formation of several oxidized derivatives and cleavage products, some of which are volatile (VCCPs). Among them, β-cyclocitral (β-CC), at least, is a retrograde signaling molecule that modulates the activity of many key physiological processes. In the present work, we aimed to study whether β-CC and other VCCPs are released into the atmosphere from photosynthetic tissues. To overcome stomatal limitations, the foliose chlorolichen Lobaria pulmonaria was used as the model system, and the emissions of biogenic volatiles, induced by heat and wounding stresses, were monitored by proton-transfer reaction time-of-flight mass-spectrometry (PTR-TOF-MS) and gas-chromatography (GC–MS). Prior to stress treatments, VCCPs were emitted constitutively, accounting for 1.3% of the total volatile release, with β-CC being the most abundant VCCP. Heat and wounding stresses induced a burst of volatile release, including VCCPs, and a loss of carotenoids. Under heat stress, the production of β-CC correlated positively with temperature. However the enhancement of production of VCCPs was the lowest among all the groups of volatiles analyzed. Given that the rates of carotenoid loss were three orders of magnitude higher than the release rates of VCCPs and that these compounds only represent a minor fraction in the blend of volatiles, it seems unlikely that VCCPs might represent a global stress signal capable of diffusing through the atmosphere to different neighboring individuals.

High Life Expectancy of Bacteria on Lichens.

Self-sustaining lichen symbioses potentially can become very old, sometimes even thousands of years in nature. In the joint structures, algal partners are sheltered between fungal structures that are externally colonized by bacterial communities. With this arrangement lichens survive long periods of drought, and lichen thalli can be revitalized even after decades of dry storage in a herbarium. To study the effects of long-term ex situ storage on viability of indigenous bacterial communities we comparatively studied herbarium-stored material of the lung lichen, Lobaria pulmonaria. We discovered that a significant fraction of the lichen-associated bacterial community survives herbarium storage of nearly 80 years, and living bacteria can still be found in even older material. As the bacteria reside in the upper surface layers of the lichen material, we argue that the extracellular polysaccharides of lichens contribute to superior life expectancy of bacteria. Deeper understanding of underlying mechanisms could provide novel possibilities for biotechnological applications.

How to optimize lichen relative growth rates in growth cabinets

AbstractIn order to improve growth chamber protocols for lichens, we tested the effect of 1) wet filter paper versus self-drained nets as a substratum for lichens, and 2) gradual versus abrupt transitions between dark and light periods. For Lobaria pulmonaria (L.) Hoffm. cultivated on nets, RGR increased by 60% compared to those on wet papers, whereas abrupt on/off transitions between day/night gave as high growth rates as gradual transitions mimicking sunrise/sunset. Because thalli on nets had less surface water than those on papers, the higher RGR on nets likely resulted from less suprasaturation depression of photosynthesis. By supporting very high growth and eliminating any visible damage, the revised growth chamber protocols facilitate new functional lichen studies.

Macrolichen diversity as an indicator of stand age and ecosystem resilience along a precipitation gradient in humid forests of inland British Columbia, Canada

The distributional ecology of 87 macrolichens is reported from 14 unmanaged mid-seral and old forest stands along a precipitation gradient in south-central British Columbia. We used a combination of univariate and multivariate statistics to investigate the role of forest structure and stand age in the distribution of epiphytic macrolichens in interior cedar-hemlock forests. Old forests support a higher number of species; although mean species richness is not significantly different between the two age classes. Terricolous and epixylic community structure is correlated with stand age and log characteristics, but the epiphtytic community is not. Epiphytic community structure is strongly associated with precipitation in the old stands, but not in the mid-seral stands. Old forests at the wetter end of the precipitation gradient contained several old-growth associated species, all of which are hygrophytic. Most epiphytic macrolichens associated with old forests are not dependent on specific structural attributes. However, western red cedar (Thuja plicata Donn ex D. Don) harbors the greatest number of arboreal macrolichen species by far in these unmanaged stands and should, therefore, be considered a key indicator in managed forests. Our study suggests that most macrolichen species found in old forests can also occur in 70- to 165-year-old forests dating from stand-replacing fires. Old forests, however, clearly provide important habitat for oceanic epiphytes at the edge of their ecological range in the interior of British Columbia. Our findings illustrate that the macrolichen flora in wet toe-slope stands in humid inland British Columbia has a high level of resilience following disturbance under natural succession conditions. It also underlines the point that some species, like Lobaria pulmonaria, are good indicators of old-growth forests in certain regions but not in others, suggesting a careful use of the term old-growth dependence.

Floristic Study of Lichens in Portage County, Wisconsin

Abstract. The results of a floristic study of lichens in Portage County, Wisconsin are presented. A total of 180 species in 73 genera were identified from field collections made in 2010 through 2013. A catalogue of species is included with 208 lichens presented as a result of field work, a literature search for previously reported collections and a physical search of the Wisconsin State Herbarium (WIS). There are 115 new records for the county and the following three species are reported for the first time for the State of Wisconsin: Leptogium rivulare, Heterodermia obscurata, and Peltigera extenuata. In addition to state and county records, two lichens of significant ecological interest were collected during this study; Lobaria pulmonaria, and Normandina pulchella.

Carbon based secondary compounds do not provide protection against heavy metal road pollutants in epiphytic macrolichens

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.

Response of the nitrogen‐fixing lichen Lobaria pulmonaria to phosphorus, molybdenum, and vanadium

Nitrogen‐fixing lichens (cyanolichens) are an important source of nitrogen (N) in Pacific Northwest forests, but limitation of lichen growth by elements essential for N fixation is poorly understood. To investigate how nutrient limitation may affect cyanolichen growth rates, we fertilized a tripartite cyanobacterial lichen (Lobaria pulmonaria) and a green algal non‐nitrogen fixing lichen (Usnea longissima) with the micronutrients molybdenum (Mo) and vanadium (V), both known cofactors for enzymes involved in N fixation, and the macronutrient phosphorus (P). We then grew treated lichens in the field for one year in western Oregon, USA. Lichen growth was very rapid for both species and did not differ across treatments, despite a previous demonstration of P‐limitation in L. pulmonaria at a nearby location. To reconcile these disparate findings, we analyzed P, Mo, and V concentrations, natural abundance δ15N isotopes, %N and change in thallus N in Lobaria pulmonaria from both growth experiments. Nitrogen levels in deposition and in lichens could not explain the large difference in growth or P limitation observed between the two studies. Instead, we provide evidence that local differences in P availability may have caused site‐specific responses of Lobaria to P fertilization. In the previous experiment, Lobaria had low background levels of P, and treatment with P more than doubled growth. In contrast, Lobaria from the current experiment had much higher background P concentrations, similar to P‐treated lichens in the previous experiment, consistent with the idea that ambient variation in P availability influences the degree of P limitation in cyanolichens. We conclude that insufficient P, Mo, and V did not limit the growth of either cyanolichens or chlorolichens at the site of the current experiment. Our findings point to the need to understand landscape‐scale variation in P availability to cyanolichens, and its effect on spatial patterns of cyanolichen nutrient limitation and N fixation.

Importance of Arboreal Cyanolichen Abundance to Nitrogen Cycling in Sub-Boreal Spruce and Fir Forests of Central British Columbia, Canada

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

Analyzing the antagonistic potential of the lichen microbiome against pathogens by bridging metagenomic with culture studies.

Naturally occurring antagonists toward pathogens play an important role to avoid pathogen outbreaks in ecosystems, and they can be applied as biocontrol agents for crops. Lichens present long-living symbiotic systems continuously exposed to pathogens. To analyze the antagonistic potential in lichens, we studied the bacterial community active against model bacteria and fungi by an integrative approach combining isolate screening, omics techniques, and high resolution mass spectrometry. The highly diverse microbiome of the lung lichen [Lobaria pulmonaria (L.) Hoffm.] included an abundant antagonistic community dominated by Stenotrophomonas, Pseudomonas, and Burkholderia. While antagonists represent 24.5% of the isolates, they were identified with only 7% in the metagenome; which means that they were overrepresented in the culturable fraction. Isolates of the dominant antagonistic genus Stenotrophomonas produced spermidine as main bioactive component. Moreover, spermidine-related genes, especially for the transport, were identified in the metagenome. The majority of hits identified belonged to Alphaproteobacteria, while Stenotrophomonas-specific spermidine synthases were not present in the dataset. Evidence for plant growth promoting effects was found for lichen-associated strains of Stenotrophomonas. Linking of metagenomic and culture data was possible but showed partly contradictory results, which required a comparative assessment. However, we have shown that lichens are important reservoirs for antagonistic bacteria, which open broad possibilities for biotechnological applications.

Erratum to “High demographic rates of the model epiphyte Lobaria pulmonaria in an oceanic hazelwood (western Scotland)” [Fungal Ecology (2013) 60–70

Erratum to “High demographic rates of the model epiphyte Lobaria pulmonaria in an oceanic hazelwood (western Scotland)” [Fungal Ecology (2013) 60–70

Relative growth rates and secondary compounds in epiphytic lichens along canopy height gradients in forest gaps and meadows in inland British Columbia

We explore relative growth rates (RGRs) and carbon-based secondary compounds (CBSCs) in epiphytic lichens along height-above-the-ground gradients. The chlorolichen (Letharia vulpina (L.) Hue), the cephalolichen (Lobaria pulmonaria (L.) Hoffm.), and the cyanolichens (Lobaria hallii (Tuck.) Zahlbr., Nephroma helveticum Ach.) were attached to branches at 0.5–3.0 m heights of young spruce trees transplanted for 1 year in forest gaps and in old meadows of an inland valley in British Columbia. Cephalolichen and cyanolichen RGRs were highest in forest gaps, whereas the chlorolichen grew faster in meadows with twice as much light as forest gaps. Transplantation height did not influence lichen temperature or RGRs, despite height-dependent light increases. CBSCs were highest in the chlorolichen (13%), followed by the cephalolichen (5%) and the cyanolichens (1% and 0%). CBSC concentrations increased with thallus size, and were significantly higher in forest gaps mainly for L. pulmonaria. Only one minor CBSC in each species varied with height. The slow growth of cephalolichen and cyanolichens in meadows is consistent with these lichens’ preferences for forested habitats. Cold air ponding from snow-capped mountains was probably strong enough to form enough nocturnal dew to support reasonable lichen growth at all heights. The high species-specific and the low habitat-specific CBSC variations are consistent with constitutive CBSC defense levels in studied lichens.

Epiphytic lichen growth in Mediterranean forests: Effects of proximity to the ground and reproductive stage

Reasonable lichen growth rates are required to maintain the important ecosystem functions provided by epiphytic lichen populations. Previously, lichen growth has mainly been quantified in boreal forests. Thus, there is a need for comparable studies from Mediterranean forests. We used reciprocal transplantation to compare relative biomass (RGR) and thallus area (RTAGR) growth rates of the cephalolichen Lobaria pulmonaria and the cyanolichen Lobarina scrobiculata (n=720 thalli) in two Mediterranean oak forests. Both juvenile and reproductive thalli were transplanted for 334 days at the base and at breast height of random trees in both forests. We measured functional traits, specific thallus mass (STM) and water holding capacity (WHC), to search for adaptation/acclimation patterns between regions and between local stands. Linear Mixed Models were used to assess the effects of (1) forest, (2) height on the trunk and (3) reproductive stage on RGR, RTAGR, and functional traits. Lobaria pulmonaria grew faster than L. scrobiculata, consistent with its more flexible hydration traits. Growth rates in both species were fastest in juveniles at the trunk bases, consistent with trade-offs between (1) growth and reproduction and (2) humidity availability and distance from the ground. In L. pulmonaria, STM increased with increasing evaporative demands, consistent with acclimation mechanisms. Fundamental and realized niches differed in L. scrobiculata, indicating that high abundance does not necessarily coincide with optimal growth habitat. Both species grew as fast in drier and warmer Mediterranean forests as reported from boreal forests, presumably because local conditions during hydration periods differ less between macroclimate regions than average climatic parameters, and/or because dew formation is frequent, particularly near the ground. Furthermore, STM and WHC of lichens in Mediterranean forests were high, thus partly compensating for the drier conditions. This study improves our understanding of mechanisms underlying epiphytic lichen growth in Mediterranean climates.

Application of molecular markers to detect DNA damage caused by environmental pollutants in lichen species.

Pseudevernia furfuracea L. (Zopf), Peltigera praetextata (Flörke ex Sommerf.) Zopf, Lobaria pulmonaria (L.) Hoffm., and Usnea longissima Ach. lichen species were used as bioindicators to assess the genotoxicity of air pollutants. In the present study, we examined significant environmetal pollutants and investigate how changes may lead to damage in DNA structure using RAPD markers. In the study area (Erzurum, Turkey), poor-quality lignite, which generates a large amount of sulfur dioxide, nitrogen oxides, and particle matter, is used for domestic heating, and vehicles also contribute to air pollution. Control lichen samples were collected far from large urban and industrial settlements and transplanted to four polluted sites for 4, 8, or 12 months. The total soluble protein content of the examined four lichen species did not significantly change with exposure time (P < 0.05). The four lichen samples exposed to the pollutants for 8 months had the highest ratio of DNA changes. The ratio of band differences in P. praetextata was higher than that in the other three lichen species, possibly because it has broad leaves that accumulated more pollutants. The average incidences of polymorphism were 64.14, 54.58, 65.76, and 43.06% for P. furfuracea, P. praetextata, L. pulmonaria, and U. longissima, respectively. The genomic template stability (GTS) significantly decreased following exposure to pollutants. GTS ratios revealed that the highest value (98.36%) belonged to U. longissima samples from Site 1 (10 m) after 4 months of exposure, and the lowest values belonged to P. praetextata (73.58%) from Site 3 (100 m) after 8 months of exposure. Based on our findings, we recommend the use of P. praetextata as an indicator of genotoxicity.

Spatial dispersal of airborne pollutants and their effects on growth and viability of lichen transplants along a rural highway in Norway

AbstractThis study aims to quantify dispersal of airborne traffic-related elemental pollutants and concurring responses – relative growth rate (RGR), maximal quantum yield of PSII (Fv/Fm), and chlorophylls (Chlab) – in four epiphytic lichens (Lobaria pulmonaria,Parmelia sulcata,Ramalina farinacea,Usnea dasopoga). Lichens were transplanted from 25 September to 26 March to 1·5 m tall stands in open farmlands at 10, 15, 30, 50 and 100 m from the E6 highway (SE Norway), along three transects on each side usnea dasopoga of the road. The concentrations of most elements (Ca, Mg,Na,Fe,Al, Zn,Ba,Cu,V,Cr,Ni,Co,Sn, As, Mo) significantly increased with increasing proximity to the road. Elements inboldhad elevated concentrations relative to controls, at least in some species at 100 m. The heavy metal accumulation increased from foliose to fruticose lichens in the order:P. sulcata&gt;L. pulmonaria&gt;R. farinacea≫U. dasopoga.However,L. pulmonariawas the only species with strong pollutant-dependent reductions in growth,Fv/Fm, Chlab, and Chla/b-ratio. The RGR and viability parameters were adversely affected by the roadside environment near the road only (≤15 m), and only after substantial heavy metal accumulation. Measurement of metal accumulation in lichens is thus a far more sensitive way of monitoring road pollutants than recording growth and lichen viability. Despite strong species-specific contrasts in elemental concentrations, most road pollutant elements responded similarly to distance from the road in all species.

Winter – the optimal logging season to sustain growth and performance of retained epiphytic lichens in boreal forests

Epiphytic lichens, comprising an important biodiversity component with significant functions in old boreal forests, are susceptible to logging. Leaving retention trees may partly compensate for the adverse effects of logging, but the impact of logging season on retained lichens is unknown. To identify the least harmful logging season seen from an epiphytic lichen perspective, we simulated logging events by transplanting two old forest model species – Lobaria pulmonaria (cephalolichen) and Lobariascrobiculata (cyanolichen) – in summer, autumn, winter and spring, respectively. Lichens were collected in intact old forests and transplanted in clear-cuts. They were placed on five aspects (N, E, S, W, and top) on artificial stands covered with bark. They all gained biomass and area in the following year. However, logging in January resulted in subsequent higher relative growth rates than in lichens being exposed to clear cuts in other seasons, consistent with clear seasonal logging effects. Aspect impacted lichen growth less than logging season, despite significant bleaching and chlorophyll contents in the most exposed aspects. The high annual growth rate and the low level of damage after transplantation to clear cuts during winter suggest that green tree retention (GTR) logging practices in winter can support life-boating of susceptible old forest lichen epiphytes. Logging simulation during other seasons than winter resulted in lower growth, implying higher risk of permanent damage. Successful use of GTR cannot compensate for the loss of epiphytes at timber harvest, but supports local retained lichen populations that subsequently may boost re-colonization of the young stand.

Vertical distribution and nitrogen content of epiphytic macrolichen functional groups in sub-boreal forests of central British Columbia

Vertical distribution, biomass abundance and nitrogen stocks of epiphytic macrolichens were examined in the two dominant tree species, interior hybrid spruce (Picea engelmannii Parry ex Engelm. x glauca (Moench) and subalpine fir (Abies lasiocarpa (Hook.) Nutt.), in sub-boreal spruce forest ecosystems of central British Columbia. Lichens were contrasted between two different site types containing either high (High Cyano) or low (Low Cyano) epiphytic cyanolichen abundance. A single rope technique was used for canopy access and a ‘clump’ method was used to estimate the abundance of arboreal lichens at different heights within both canopy tree species for five functional groups: Bryoria spp., Alectoria sarmentosa, foliose chlorolichens, bipartite cyanolichens, and Lobaria pulmonaria (the only tripartite cyanolichen). In this way, the relationship between average lichen biomasses and tree height for each tree species were assessed. We determined that biomass was dependent on tree height and species, with a greater abundance of lichen appearing on fir trees (mean±SD; 1588±428gtree−1) than the generally taller spruce trees (917±422gtree−1). Foliose chlorolichen biomass was more abundant in trees with low abundance of L. pulmonaria (777.1±365.9gtree−1) than those with a high abundance of L. pulmonaria (553.6±400gtree−1). Much of this increase in chlorolichen biomass in trees with low cyanolichen abundance was a result of greater chlorolichen abundances in lower canopy positions where cyanolichens would otherwise predominate. Although bipartite cyanolichens had a higher %N (∼3.2%N) than L. pulmonaria (2.3%N) of dry mass, there was a much higher abundance of L. pulmonaria in the canopy of High Cyano sites containing a larger amount of N (4.04±0.95kgNha−1) than in all bipartite cyanolichens combined (2.33±1.11kgNha−1) or any other lichen spp. Chlorolichens are poor competitors for lower branch positions when cyanolichens such as L. pulmonaria are abundant, the latter of potential importance for N inputs into N-limited sub-boreal forests of central BC.

Rehydration conditions for isolation of high quality RNA from the lichen Lobaria pulmonaria.

BackgroundThe poikilohydric nature of lichens enables them to survive repeated episodes of desiccation by utilizing water when it becomes available. During rehydration, RNA-degrading endonucleases may be released, reducing RNA quantity and quality. Re-generation of a steady-state condition where RNA quantity and quality no longer fluctuate establishes a framework for development of new hypotheses for future investigations. Using Lobaria pulmonaria as a model species, the objective of this study was to compare the effect of different rehydration conditions on the quantity and quality of RNA from the rehydrated thallus.FindingsSpectrophotometric measurements of total RNA and cDNA were performed for samples prepared from dry lichen or lichen after rehydration (0.5 h, 1 h, 2 h, 4 h or 24 h), with limited light and dark conditions, and at three temperatures (15°C, 20°C or 32°C) for some of these conditions. The results showed that rehydration of the thallus for 4 h at 20°C in light yielded the highest concentration and quality of RNA. A higher RNA concentration was obtained in light than in dark conditions, but the RNA quality was unaffected.ConclusionsThis study suggests that allowance of 4 h for thallus rehydration should be adequate to ensure complete recovery of transcription. After 4 h at 20°C further studies can be carried out on the RNA in this model species.

High demographic rates of the model epiphyte Lobaria pulmonaria in an oceanic hazelwood (western Scotland)

The lichen Lobaria pulmonaria is a case-study species for research in forest ecology. Previous studies have emphasised both its niche specialism and slow growth with long generation times, explaining its occurrence on larger/older trees in forest stands with long temporal continuity. Contrastingly, L. pulmonaria is common among a broader range of habitats within an oceanic (‘temperate rainforest’) bioclimatic zone, and we investigate its population dynamics within this context to expand our understanding of the ecology of this model organism. The results indicated some of the highest growth rates and shortest generation times observed globally, with reproductive maturity achieved within c. 5–10 yr. This rapid growth to maturity and raised propagule density can explain the rapid colonisation of L. pulmonaria onto very young hazel stems. The work emphasises the viability of large populations of L. pulmonaria in western Scotland, underlining an International Responsibility for protection within a European context.

Unequal allocation of excitation energy between photosystem II and I reduces cyanolichen photosynthesis in blue light.

Photosynthesis was compared in two cyanobacterial lichens (Lobaria hallii and Peltigera praetextata) and two green algal lichens (Lobaria pulmonaria and Peltigera leucophlebia) exposed to red, green or blue light. Cyanolichens had substantially lower photosynthetic CO(2) uptake and O(2) evolution than the green algal lichens in blue light, but slightly higher photosynthesis in red and green light. The effective quantum yield of photosystem (PS) II (Φ(PSII)) decreased with increasing red and green light for all species, but in blue light this response occurred in green algal lichens only. Cyanolichen Φ(PSII) increased with increasing blue light at low irradiances, but decreased at stronger exposures. However, after adding red light the efficiency of blue light for photosynthetic O(2) evolution increased by 2.4 times. Because phycobilisomes associated with PSII have a low blue light absorption, our results are consistent with blue light absorption mainly by Chl in PSI. Thereby, unequal allocation of excitation energy between PSII and PSI results in low cyanolichen photosynthesis under blue light. This is new knowledge in the science of lichenology with important implications for e.g. the reliability of using Chl fluorometers with blue light for cyanolichens.