Variability of lichen diversity in a climatically heterogeneous area (Liguria,NW Italy)

Abstract:The influence of environmental variables on epiphytic lichens in Liguria (NW Italy) was examined using two complementary approaches. Firstly, the variability of lichen vegetation in relation to environmental variables was investigated. Secondly, the variability of Lichen Biodiversity (LB) counts, used in biomonitoring studies, was analysed in relation to bioclimatic areas. Geomorphology strongly affects lichen vegetation. The coastal mountain ridge and the Tyrrhenian-Po valley watershed limit the distribution range of three different communities: a Parmelion community with a high frequency of coastal suboceanic species, a Parmelion community rich in oak wood species and the Parmelietum acetabuli association, situated beyond the Po Valley watershed. Substantial differences in the distribution of lichen communities related to a climatic gradient (from humid Mediterranean to dry sub-Mediterranean regions) are not matched by corresponding statistically significant differences in LB counts. More accurate studies are necessary to define homogeneous bioclimatic areas, in which LB values can be compared for biomonitoring purposes.     

Ancient woodland indicators signal the climate change risk for dispersal-limited species

The climate change risk to biodiversity operates alongside a range of anthropogenic pressures. These include habitat loss and fragmentation, which may prevent species from migrating between isolated habitat patches in order to track their suitable climate space. Predictive modelling has advanced in scope and complexity to integrate: (i) projected shifts in climate suitability, with (ii) spatial patterns of landscape habitat quality and rates of dispersal. This improved ecological realism is suited to data-rich model species, though its broader generalisation comes with accumulated uncertainties, e.g. incomplete knowledge of species response to variable habitat quality, parameterisation of dispersal kernels etc. This study adopts ancient woodland indicator species (lichen epiphytes) as a guild that couples relative simplicity with biological rigour. Subjectively-assigned indicator species were statistically tested against a binary habitat map of woodlands of known continuity (>250 yr), and bioclimatic models were used to demonstrate trends in their increased/decreased environmental suitability under conditions of ‘no dispersal’. Given the expectation of rapid climate change on ecological time-scales, no dispersal for ancient woodland indicators becomes a plausible assumption. The risk to ancient woodland indicators is spatially structured (greater in a relative continental compared to an oceanic climatic zone), though regional differences are weakened by significant variation (within regions) in woodland extent. As a corollary, ancient woodland indicators that are sensitive to projected climate change scenarios may be excellent targets for monitoring climate change impacts for biodiversity at a site-scale, including the outcome of strategic habitat management (climate change adaptation) designed to offset risk for dispersal-limited species.     

Tree and stand-scale factors affecting richness and composition of epiphytic bryophytes and lichens in deciduous woodland key habitats

Conservation and sustainable forestry are essential in a multi-functional landscape. In this respect, ecological studies on epiphytes are needed to determine abiotic and biotic factors associated with high diversity. The aim of the present study was to evaluate relative sensitivity of conservation targets (epiphytic bryophytes and lichens) in relation to contrasting environmental variables (tree species, tree diameter at breast height, bark crevice depth, pH, tree inclination, pH, forest stand age, area and type) in boreo-nemoral forests. The study was conducted in Latvian 34 woodland key habitat (WKH) boreo-nemoral forest stands. Generalized linear mixed models and canonical correspondence analysis showed that tree species and tree bark pH were the most important variables explaining epiphytic bryophyte and lichen composition and richness (total, Red-listed, WKH indicator species). Forest stand level factors, such as stand size and habitat type, had only minor influence on epiphytic species composition and richness. The results of the present study indicate a need to maintain the diversity of tree species and large trees, particularly Acer platanoides, Carpinus betulus, Fraxinus excelsior, Populus tremula, Tilia cordata, Ulmus glabra and Ulmus laevis in conservation of epiphytic bryophyte and lichen communities in the future.     

Mapping and analysis of distribution patterns of lichens on rural medieval churches in north-eastern Germany

Abstract:Lichen communities were examined on 62 churches in Mecklenburg-Vorpommern, Germany. Ninety-six lichen species and subspecies, and three species of lichenicolous fungi were identified. Tylothallia biformigera and Lecanora campestris subsp. dolomitica are reported as new to Germany, and another 20 species are considered as threatened. This implies that the stone walls of churches represent an extremely important habitat in Mecklenburg-Vorpommern, where natural rock outcrops are rare. The distribution of lichen species was analyzed quantitatively in relation to several habitat factors. Aspect, substratum and inclination were found to be important factors for 35, 34 and 31 species, respectively. The height of the relevé was a significant factor for many species. Twenty-three species, which are described in the literature with oceanic to suboceanic distributions, occur significantly more frequently near the coast. The ways in which microclimate affects each of these habitat factors and contributes to the presence or absence of a species or group of species are discussed. Some species have narrow and specific habitat demands, whereas others thrive under a wide range of environmental conditions. The advantages of a strictly schematic approach with a detailed statistical analysis are discussed.     

Functional diversity and traits assembly patterns of lichens as indicators of successional stages in a tropical rainforest

Understanding community assembly patterns with regard to functional traits, which may be common to different species, allows us to compare ecological communities in a wider range of environmental and phytogeographic conditions. Moreover, a functional approach may facilitate the comprehension of the relation between biotic changes and ecosystem functions in complex systems such as tropical forests. Considering the lack of information in relation to the influence of environmental conditions on lichen functional traits, on lichen functional patterns in tropical forests and the potential usage of this approach in bioindication studies, this paper aims at (i) determining the functional structure of the lichen communities along the forest succession gradient, (ii) assessing the relation of lichen functional traits to this gradient and (iii) verifying the potential of using lichen functional traits as indicators of successional stages in tropical rainforests. Lichens were sampled in 24 sampling units of three successional stages (6–10; 12–20; and 40–60 years of recovering). The results corroborated our main hypothesis that the functional structure of the lichen communities responds to structural changes along a forest regeneration gradient. Growth forms (foliose, fruticose and crustose) as well as some reproductive trait states (lirella, isidia and perithecia) were the most suitable lichen traits to be used as indicators of forest succession in the southern edge of the Atlantic Rainforest. Lirella, fruticose and foliose were more related to earlier successional stages; isidia was more related to intermediate stages, while perithecia and crustose were more related to older stages. These results reinforce the ability of lichens to be used as bioindicators of forest conditions.     

Bole epiphytic lichens as potential indicators of environmental change in subtropical forest ecosystems in southwest China

Lichen epiphytes are applied as excellent environmental indicators worldwide. However, very little is known about epiphytic lichen communities and their response to forest dynamics in subtropical China. This paper proposes the applications of the cover, diversity, and functional traits of epiphytic lichens to assess environmental changes associated with succession in subtropical forests of southwest China. Bole lichens were sampled from 120 plots of eight representative forest types in the Ailao Mountains. Total cover, species richness, diversity and community structure of bole lichens differed significantly among forest types, and the highest cover and diversity occurred in the Populus bonatii secondary forest (PBSF). Sixty-one indicator species were associated with particular forest types and more than 50% occurred in the PBSF. Both cover and diversity of most lichen functional groups varied regularly during forest succession. Lichen pioneer species were not displaced by competitively superior species as succession proceeds and cyanolichens were more prevalent in secondary forests. The results also highlight the importance of habitat variables such as canopy openness, host diversity, forest age, tree size, the size of the largest tree, tree density, and basal area on the lichen community. Consequently, our findings support the notion that epiphytic lichens, in terms of cover, diversity, species composition and functional traits can be used as effective indicators for large-scale and long-term forest monitoring. More importantly, the narrowly lobed foliose group was the best candidate indicator of environmental conditions in this region. The combined application of lichen indicator species and functional groups seemed to be a more reliable and more powerful method for monitoring forest dynamics in subtropical montane ecosystems.     

Patterns and drivers of lichen species composition in a NW-European lowland deciduous woodland complex

We surveyed lichens in an extensive area of lowland deciduous oak and beech dominated forest under wood pasture management within the New Forest National Park, southern England. This provided the basis for an investigation of factors affecting the species density and composition of epiphytic lichen communities. Fifteen 1 hectare plots were established in the same sites as a parallel invertebrate survey, of which nine were in old growth forest and six in oak plantations of between c. 150 and 300 years old. In each plot 12 trees were identified for sampling and lichens were sampled on four aspects of each trunk. Results at the plot level showed that species density was significantly higher in the old growth woodland plots from those in plantations. Plot age had a significant effect on species on oak but this was not significant for lichen communities on beech. The species density of lichens associated with Trentepohliaceae photobionts on oaks showed a linear positive relationship with increasing plot age while the species density of species with other coccal green Chlorophyta decreased with age of the plot. A major part of the lichenised fungi with Trentepohliaceae photobionts includes indicator and notable species used in conservation evaluation and this component is most affected by fragmentation and isolation of forest sites. The results emphasise the importance of long term connectivity and ecological continuity in this extensive mosaic of lowland deciduous forest.     

Environmental context shapes the bacterial community structure associated to Peltigera cyanolichens growing in Tierra del Fuego,Chile

The structure of the associated bacterial community of bipartite cyanolichens of the genus Peltigera from three different environmental contexts in the Karukinka Natural Park, Tierra del Fuego, Chile, was assessed. The sampling sites represent different habitat contexts: mature native forest, young native forest and grassland. Recently it has been determined that the bacterial community associated to lichens could be highly structured according to the mycobiont or photobiont identities, to the environmental context and/or to the geographic scale. However, there are some inconsistencies in defining which of these factors would be the most significant on determining the structure of the microbial communities associated with lichens, mainly because most studies compare the bacterial communities between different lichen species and/or with different photobiont types (algae vs. cyanobacteria). In this work bipartite lichens belonging to the same genus (Peltigera) symbiotically associated with cyanobacteria (Nostoc) were analyzed by TRFLP to determine the structure of the bacterial community intimately associated with the lichen thalli and the one present in the substrate where they grow. The results indicate that the bacterial community intimately associated differs from the one of the substrate, being the former more influenced by the environmental context where the lichen grows.     

Differential effects of goat browsing on herbaceous plant community in a two-phase mosaic

The impact of herbivores on herbaceous plant communities is usually attributed to direct consumption of plants. We hypothesized that goats affect herbaceous plants both directly (consumption by foraging) and indirectly, by changing environmental conditions through modification of woody plant structure. We assessed the effects of goats browsing on environmental conditions, landscape structure, and herbaceous plants to link the direct and indirect effects of goats on herbaceous communities. Our model system was the Mediterranean woodland in Mt. Carmel, Israel. This is a two-phase mosaic landscape, composed of herbaceous (open) and woody patches. We delineated 10 plots of 1000 m², goats were introduced to five plots and five plots remained without goats. We monitored plant species richness and composition in two adjacent patch types (woody and open) in each plot. For each patch type, in all plots, we collected data on environmental conditions. We analyzed landscape structure using landscape metrics derived from a high-resolution vegetation map. We found that goats modified the structure of woody plants and hence the landscape mosaic. This alteration was associated with changes in environmental conditions, with more light penetration and higher temperatures. The impact of goats on the herbaceous plant community depended on patch type. In open patches, goats affected the herbaceous community mostly by direct consumption, whereas in woody patches they affected the herbaceous community mainly by modification of abiotic conditions. Our results stress the importance of considering landscape and patch structure in analyzing the effect of herbivory on plant communities.     

The potential contribution of conifer plantations to the UK Biodiversity Action Plan

Summary

The detrimental effects of conifer plantations on open ground habitats have been well catalogued and discussed, but the potential contribution of planted forests to the conservation of woodland biodiversity has not been quantified to the same extent. This quantification is needed urgently to help forest managers fulfil commitments to biodiversity enhancement as outlined in the UK Biodiversity Action Plan, the UK Forestry Standard and the UK Woodland Assurance Scheme (UKWAS). Results are presented from a five-year programme of research aimed at obtaining baseline information on biodiversity in planted forests and evaluating the contribution of planted forests to the conservation of native flora and fauna. Fifty-two plots were surveyed in total, covering a range of different tree crops (Scots pine Pinus sylvestris L., Sitka spruce Picea sitchensis (Bong.) Carr., Norway spruce Picea abies L. and Corsican pine Pinus nigra var maritima (Aitón) Melville) and stand ages (pre-thicket, mid-rotation, mature and over-mature) in three contrasting bioclimatic zones (upland, foothills and lowlands) throughout Britain. Additional plots were established in semi-natural woodland to allow comparisons between the biodiversity of plantations and native stands. Over 2000 species were recorded in total, including 45 Red Data Book species. Planted stands had similar or richer fungal and invertebrate communities to those of the native stands but poorer lichen and vascular plant communities. The latter were strongly affected by shading, dense, mid-rotation Sitka spruce stands having the lowest species counts. In contrast, these stands had a high diversity of mycorrhizal fungi, including a number of rare and threatened species normally associated with native pine wood. Bryophyte species-richness was related more to climate than woodland type, with the wetter upland spruce and native oak stands having the most diverse communities. Compared to the younger planted stands, over-mature planted stands had a higher proportion of species characteristic of semi-natural woodland stands. This related to greater structural diversity and higher deadwood volumes in the over-mature stands. It is concluded that conifer plantations make a positive contribution to biodiversity conservation in the UK and hence to the UK Biodiversity Action Plan. No single stand or crop type provides ‘optimal’ conditions for biodiversity, but the habitat value of plantations could be enhanced by increasing the area managed under alternative systems to clear-felling, such as ‘continuous cover’ and/or non-intervention natural reserves.     

Patterns of β-diversity and similarity reveal biotic homogenization of epiphytic lichen communities associated with the spread of black locust forests

We compared epiphytic lichen communities of native broadleaved and secondary black locust (Robinia pseudoacacia) forests to detect possible differences in community structure that could be indicative of biological homogenization enhanced by the replacement of native by black locust forests. The study was carried out in two areas of Italy with different bioclimatic conditions using a balanced stratified random sampling. Results reveal a different pattern of community structure between native and black locust forests across the two regions that may reflect a process of biological homogenization. In particular, lichen communities of black locust forests share several species between the two study regions. This pattern of floristic homogenization parallels with a functional homogenization related to the spread of highly competitive species. This research provides early evidence that the decrease of native forests associated with the spread of black locust is a mechanism triggering biological homogenization of the epiphytic lichen biota.     

Integrating multiple landscape-scale drivers in the lichen epiphyte response: climatic setting, pollution regime and woodland spatial-temporal structure

Aim To quantify the role of multiple biodiversity drivers – pollution, woodland structure and climate – controlling lichen epiphyte composition and diversity. Location  Scotland, north‐west Europe. Methods Four compatible datasets were assembled: site‐scale species distribution data (response) and base‐line modelled data on climate, pollution loads and extent of old‐growth woodland (explanatory variables). First, partial‐canonical correspondence analysis was used: (1) to compare the importance of environmental variables to pure spatial effects and (2) to partition the importance of environmental variables in explaining species composition. Secondly, patterns of species richness were investigated using multiple least‐squares regression. Results Old‐growth woodland was the most important control of species richness. Pollution was the most important explanatory variable for species composition. The impact of pollution on composition (and to a lesser extent on richness) is explained: (1) By recovery of lichens with declining SO₂ pollution, although with epiphyte composition shifted by the recent effects of N‐pollution and (2) By the limited spatial extent of severe pollution, and generally low‐to‐moderate pollution loads across our study area, combined with the positive effect of old‐growth woodland extent in controlling species richness. The effect of climate and old‐growth woodland on species composition covaried, supporting an interaction between habitat quality and climatic setting, which may be important in understanding the epiphyte response to climate change. Conclusions Advances in conservation planning will likely require an integrated approach to understanding simultaneous effects of multiple drivers, providing opportunities for integrated management strategies. Our study provides a preliminary example of this approach by combining three key biodiversity drivers into a single framework for lichen epiphytes. Thus, reducing pollution loads may make old‐growth woodland that currently exists in a polluted landscape available for colonization, thereby extending the available habitat for epiphytes, and facilitating an effective species response to climate change.     

Análisis ecológico de las comunidades liquénicas de la Catedral de León (España)

Ecological analysis of Leon Cathedral lichen communities (Spain).A study of the lichen communities present on Leon Cathedral showed there to be 39 species present, mainly crustose forms of the Teloschistaceae and Lecanoraceae. Two lichen communities were found on calcareous stonework and on highly nitrified habitats. Species distribution depends mainly on nitrophytism, hygrophytism, photophytism and pH indexes, and to a lesser extent on angle of inclination, exposure and substrate type.     

Species richness of vascular plants, bryophytes and lichens in dry grasslands: The effects of environment, landscape structure and competition

We studied the relative importance of local habitat conditions and landscape structure for species richness of vascular plants, bryophytes and lichens in dry grasslands on the Baltic island of Öland (Sweden). In addition, we tested whether relationships between species richness and vegetation cover indicate that competition within and between the studied taxonomic groups is important. We recorded species numbers of vascular plants, bryophytes and lichens in 4 m² plots (n=452), distributed over dry grassland patches differing in size and degree of isolation. Structural and environmental data were collected for each plot. We tested effects of local environmental conditions, landscape structure and vegetation cover on species richness using generalized linear mixed models. Different environmental variables explained species richness of vascular plants, bryophytes and lichens. Environmental effects, particularly soil pH, were more important than landscape structure. Interaction effects of soil pH with other environmental variables were significant in vascular plants. Plot heterogeneity enhanced species richness. Size and degree of isolation of dry grassland patches significantly affected bryophyte and lichen species richness, but not that of vascular plants. We observed negative relationships between bryophyte and lichen species richness and the cover of vascular plants. To conclude, effects of single environmental variables on species richness depend both on the taxonomic group and on the combination of environmental factors on a whole. Dispersal limitation in bryophytes and lichens confined to dry grasslands may be more common than is often assumed. Our study further suggests that competition between vascular plants and cryptogams is rather asymmetric.     

Local extent of old-growth woodland modifies epiphyte response to climate change

Aim To quantify the interaction between climate and woodland continuity in determining the bioclimatic response of lichen epiphytes. Location Northern Britain (Scotland). Methods Indicator‐species analysis was used to pre‐select lichen epiphytes along parallel gradients in climate and the extent of old‐growth woodland. Nonparametric multiplicative regression was used to describe in a predictive model the individualistic response of selected species, which were projected based on climate‐change scenarios and contrasting patterns of simulated woodland loss or gain. Species with a similar response were grouped using a novel application of cluster analysis to summarize the potentially huge number of projected outcomes. Projected patterns of occurrence under climate‐change scenarios were examined for different levels of old‐growth woodland extent. Results Forty‐two lichen species were statistically significant indicator species in oceanic woodlands, and old‐growth indicators under suboptimal climatic conditions. Responses to climate‐change scenarios were contrasting, with one group comprising species projected to increase in extent in response to climate warming, and other response groups projected to decrease in occurrence, possibly in response to shifting rainfall patterns. The occurrence of all response groups had a positive relationship with old‐growth woodland extent. Main conclusions An ‘oceanic’ biogeographical group of epiphytes identified using the baseline climatic and present‐day woodland setting comprised species with a cyanobacterial photobiont or tropical phytogeographical affinities. However, within this group the individual species responses to climate‐change scenarios were contrasting. Additionally, group responses may be poorly matched with simple ecological traits. However, the studied interaction between climate and habitat continuity suggests that the impact of climate change might be offset for certain lichen epiphytes by appropriate management of woodland resources, for example, expansion of native woodland around remnant old‐growth stands.     

Tree species and microhabitat influence the population structure of the epiphytic lichen Lobaria pulmonaria

Detailed knowledge of the habitat requirements of species is required because habitat greatly affects the persistence of species. We investigated the effects of tree species and microhabitat heterogeneity on the population of the locally threatened lichen Lobaria pulmonaria. We studied four L. pulmonaria populations in Central Spain and collected microhabitat data for individuals growing on beech and oak. The microhabitat affected the life stages of L. pulmonaria; being a phorophyte species the location of the lichen was the most important factor generating different patterns of establishment, abundance, thallus size and reproductive capacity. Although oak forests favoured the establishment and recruitment of new L. pulmonaria individuals, they apparently provided adverse environmental conditions for lichen growth, thus affecting the reproductive capacity since this is size-dependent. By contrast, beech forests offered a more favourable microclimate, because L. pulmonaria individuals reached larger sizes in these forests. In conclusion, our results indicate that habitats hosting large populations, with high rates of establishment and recruitment do not necessarily favour other life-cycle stages.     

Endolithic Microbial Colonization of Limestone in a High-altitude Arid Environment

The morphology of endolithic colonization in a limestone escarpment and surrounding rocky debris (termed float) at a high-altitude arid site in central Tibet was documented using scanning electron microscopy. Putative lichenized structures and extensive coccoid bacterial colonization were observed. Absolute and relative abundance of rRNA gene signatures using real-time quantitative polymerase chain reaction and phylogenetic analysis of environmental phylotypes were used to characterize community structure across all domains. Escarpment endoliths were dominated by eukaryotic phylotypes suggestive of lichenised associations (a Trebouxia lichen phycobiont and Leptodontidium lichen mycobiont), whereas float endoliths were dominated by bacterial phylotypes, including the cyanobacterium Chroococcidiopsis plus several unidentified beta proteobacteria and crenarchaea. Among a range of abiotic variables tested, ultraviolet (UV) transmittance by rock substrates was the factor best able to explain differences in community structure, with eukaryotic lichen phylotypes more abundant under conditions of greater UV-exposure compared to prokaryotes. Variously pigmented float rocks did not support significantly different communities. Estimates of in situ carbon fixation based upon ¹⁴C radio-labelled bicarbonate uptake indicated endolithic productivity of approximately 2.01 g C/m²/year^?1, intermediate between estimates for Antarctic and temperate communities.     

Defining the twig fungal communities of Fraxinus species and Fraxinus excelsior genotypes with differences in susceptibility to ash dieback

Ash dieback disease (caused by Hymenoscyphus fraxineus) has affected European ash species (Fraxinus spp.) in recent decades. However, some Asian and American species of Fraxinus and certain genotypes of Fraxinus excelsior are less affected by the disease. We used ITS1-metabacoding to explore the drivers influencing diversity and composition of the twig fungal communities of Fraxinus species and F. excelsior genotypes. Our results revealed that fungi in the classes Eurotiomycetes and Dothideomycetes were among the most prevalent taxa in both Fraxinus species and F. excelsior genotypes. The diversity of the fungal communities differed significantly among Fraxinus species and could be explained by seed origin. Neither host genotype nor season had a significant effect on the community diversity of F. excelsior genotypes. On the other hand, the composition of twig fungal communities differed significantly among host species and among F. excelsior genotypes, and in F. excelsior there was also a significant effect of season on the composition of the fungal community. We did not find a clear effect of ash dieback susceptibility on either diversity or composition of fungal communities in twigs of Fraxinus species, although the effect was significant on the composition of fungal communities among F. excelsior genotypes. Our results demonstrated differences in fungal communities among species of Fraxinus and of F. excelsior genotypes, suggesting specific relationship between individual host genotypes and endophytic fungi.     

Changing climate and historic‐woodland structure interact to control species diversity of the ‘Lobarion’ epiphyte community in Scotland

Question: How will changing climate and habitat structure interact to control the species diversity of lichen epiphytes? Location: Scotland. Method: Species richness (=diversity) of the epiphyte lichen community known as Lobarion (named after Lobaria pulmonaria) was quantified for 94 Populus tremula stands across Scotland, and compared in a predictive model to seven climate variables and eight measures of woodland structure. An optimum model was selected and used to project Lobarion diversity over the geographic range of the study area, based on IPCC climate change scenarios and hypothetical shifts in woodland structure. Results: Species diversity of the Lobarion community was best explained by three climate variables: (1) average annual temperature; (2) autumn and winter precipitation; in combination with (3) historic‐woodland extent. Projections indicate a positive effect of predicted climate change on Lobarion diversity, consistent with the physiological traits of cyanobac‐terial lichens comprising the Lobarion. However, the general response to climate is modified significantly by the effect on diversity of historic‐woodland extent. Conclusions: Historic‐woodland extent may exert an important control over local climate, as well as impacting upon the metapopulation dynamics of species in the Lobarion. In particular, a temporal delay in the response of Lobarion species to changed woodland structure is critical to our understanding of future climate change effects. Future Lobarion diversity (e.g. in the 2050s) may depend upon the interaction of contemporary climate (e.g. 2050s climate) and historic habitat structure (e.g. 1950s woodland extent). This is supported by previous observations for an extinction debt amongst lichen epiphytes, but suggests an extension of simple climate‐response models is necessary, before their wider application to lichen epiphyte diversity.     

First evidence for seasonal fluctuations in lichen- and bark-colonising fungal communities

Endophytic fungal communities in leaves of deciduous trees usually undergo pronounced seasonal changes. We hypothesised that such compositional shifts are predominantly caused by annuality of the leaves and therefore less pronounced in fungi colonising the perennial substrates bark and corticolous lichens. To test this hypothesis, thalli of the foliose lichen-forming fungal species Xanthoria parietina and Physconia distorta, along with the adjacent bark, were sampled during spring and autumn at two sides of a single tree in southern Germany. Analysis of clone libraries by restriction fragment length polymorphism (RFLP) revealed 588 singleton and 221 non-singleton RFLP-types of non-lichenised fungi. The communities differed significantly between host lichen species. Season and exposure had only a significant impact when the two factors were combined in the analysis. Accordingly, bark- and/or the lichen-associated fungal communities change throughout the year’s course, a finding that rejects the initial hypothesis. This survey revealed valuable information for future broad-based studies, by indicating that a relatively high diversity of non-lichenised fungi is associated with corticolous lichen thalli and the adjacent bark. Furthermore, the structure of non-lichenised fungal assemblages associated with corticolous lichen communities obviously depends at least on the following factors: ‘lichen species’, ‘exposure’, and ‘season’.