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Biological invasions represent a global threat to biodiversity. Particular attention should be made to the management of alien plants. The species from the Carpobrotus genus are well-known invasive plants native to South Africa, whose detrimental effects on native communities are widely documented. These impacts have become particularly important in terms of their invasive potential on small Mediterranean islands, where they often threaten particular ecosystems and endemic species. We report the experience from the efforts to eradicate this species from the island of Giannutri (Tuscan Archipelago, Italy)—an action included within the EU LIFE project “RESTO CON LIFE”—where the species occurred on about 14,000 m2 of coastal vegetation. The eradication employed an integrated approach with two control methods (manual removal and covering with mulching sheets) and involved mosaic rocky cliff coastal vegetation and disturbed areas with loose soil close to the cliffs. We present here the results obtained from five years of monitoring using permanent plots. Carpobrotus spp. exerted strong impacts on the invaded plant communities, with significant depletion and replacement of native species. Both of the control methods proved effective in the suppression of the mat formed by the invasive species and led to a positive response of native vegetation. Nevertheless, the recovery of native plant communities differed depending on the type of substratum, taking longer on rocky cliffs due to the harsher conditions. Improvements were driven by nitrophilous species in the plots treated with mulching sheets.

Introduction One of the main topics of astrobiology research is the study of life’s limits in stressful environments. The study of organisms in extreme environments might give an indication about their potential adaptive plasticity, in the view of a climate change perspective, the terrestrial geological past and future scenarios, as well as extra-terrestrial habitats such as Mars’ surface. Lichens - with their excellent adaptive abilities - represents an extremely interesting case study. Several astrobiological studies involving lichens - that are symbiotic association between a fungus and an alga and/or acyanobacterium - proved the ability of these organisms to resist and thrive in extreme environments such as space and Mars’ surface simulated conditions [1, 2]. We have already tested the lichen species Xanthoria parietina (L.) Th. Fr. in simulated space conditions, that was able to survive and to reactivate after exposure [3]. X. parietina is a cosmopolitan foliose lichen that grows on barks and rocks [4]. This species shows high tolerance to air pollutants, heavy metals, and resistance to UV-radiation thanks to the shielding properties of the secondary metabolite parietin [5, 6]. Here we present a new study on the survival of X. parietina under simulated Mars conditions performed at the Mars Simulation Facility of the DLR Institute of Planetary Research in Berlin (Fig.1). Figure 1 - Mars Simulation Facility at DLR with the opened experiment chamber. Methods The aim of the study was to assess the survivability of Xanthoria parietina under simulated Mars conditions for 30 days [7, 8]. Inside the Mars simulation chamber, eight samples (Fig.2) were exposed to the simulated atmospheric conditions of Mars of which four were fully UV-irradiated with day-night cycles (FM, Full-Mars) and the other four kept in darkness (DM, Dark-Mars). A three-gas mixture of 95% CO2, 4% N2 and 1% O2 was used as best approximation of Mars-like atmospheric conditions, with a constant pressure of 600Pa. Temperature and humidity were subjected to day-night cycles, reaching during daytime 15°C and 0% RH, and during night -55°C and 100% RH (Fig.3) according to Martian thermophysical conditions at mid-latitudes. UV-radiation for FM samples was simulated using a Xenon UV-lamp (spectral range 200 nm – 2200 nm) that was automatically turned on for 16 h (day) and turned off for 8 h (night) daily. The total average radiation dose for FM was 2452.32 J/cm2 and the average instantaneous irradiance on the sample spots was 14,2 W/m2 [9]. Four other samples (Fig.2) were kept in control conditions during the experiment, at the constant temperature of 25°C, daily wetted and 12h dark and 12h light (ca. 50 μmol m-2 s-1 PAR photons). Several analyses were carried out to study all the samples before, during and after the exposure to the extreme Mars conditions. In detail, this experiment was performed aiming: to monitor the lichen vitality through chlorophyll a fluorescence (FV/FM) as photosynthetic efficiency parameter, carrying out in situ and after treatment analyses, to evaluate the oxidative stress due to the extreme conditions, highlighting eventual changes in the lichen carotenoids’ Raman signatures, to verify eventual modifications in the infrared features (peak shifting) in the lichen FTIR reflectance spectrum possibly related to UV-photodegradation effects, to highlight possible variations in the lichen ultrastructure through TEM analysis. Figure 2 - Xanthoria parietina samples ready for the experiment. First row (from above): full Mars samples, second row: dark Mars samples, third row: control samples. Figure 3 - Detail of the day-night cycles of the simulated Mars conditions (temperature, red thick line; humidity, blue thin line) and fluorescence variation values for both the treatments (FM and DM). Results The results showed significant differences between FM and DM photosynthetic efficiency parameter during exposure to Mars environment, exhibiting FV/FM values correlated with temperature and humidity day-night cycles (Fig.3). The FV/FM recovery values showed significant differences between the treatments too, highlighting that FM conditions caused stronger effects on fluorescence values. Additional analyses show possible changes in the Raman and FTIR spectra of the irradiated samples with several features involved. Overall, Xanthoria parietina was able to survive to FM conditions, and for this reason it may be considered a candidate for long exposure in space and evaluations on the photodegradability of parietin in extreme conditions. Reference [1] Onofri, S., de la Torre, R., de Vera, J. P., Ott, S., Zucconi, L., Selbmann, L., Scalzi, G., Venkateswaran, K. J., Rabbow, E., Sánchez Iñigo, F. J., and Horneck, G. (2012). Survival of rock-colonizing organisms after 1.5 years in outer space. Astrobiology, 12(5), 508-516. [2] De Vera, J. P., Möhlmann, D., Butina, F., Lorek, A., Wernecke, R., and Ott, S. (2010). Survival potential and photosynthetic activity of lichens under Mars-like conditions: a laboratory study. Astrobiology, 10(2), 215-227. [3] Lorenz, C., Bianchi, E., Benesperi, R., Loppi, S., Papini, A., Poggiali, G., & Brucato, J. R. (2022). Survival of Xanthoria parietina in simulated space conditions: vitality assessment and spectroscopic analysis. International Journal of Astrobiology, 1-17. [4] Nimis P.L., 2016. ITALIC - The Information System on Italian Lichens. Version 5.0. University of Trieste, Dept. of Biology, (http://dryades.units.it/italic), accessed on 2022, 05, 09. for all data contained in the taxon pages, including notes, descriptions, and ecological indicator values. [5] Silberstein, L., Siegel, B., Siegel, S., Mukhtar, A., and Galun, M. (1996). Comparative Studies on Xanthoria parietina, a Pollution Resistant Lichen, and Ramalina duriaei, a Sensitive Species. I. Effects of Air Pollution on Physiological Processes. The Lichenologist, 28:355-365. [6] Solhaug, K. A., and Gauslaa, Y. (1996). Parietin, a photoprotective secondary product of the lichen Xanthoria parietina. Oecologia, 108:412-418. [7] Lorek, A., and Koncz, A. (2013). Simulation and measurement of extraterrestrial conditions for experiments on habitability with respect to Mars. In Habitability of Other Planets and Satellites (pp. 145-162). Springer, Dordrecht. [8] De Vera, J. P., Schulze-Makuch, D., Khan, A., Lorek, A., Koncz, A., Möhlmann, D., and Spohn, T. (2014). Adaptation of an Antarctic lichen to Martian niche conditions can occur within 34 days. Planetary and Space Science, 98, 182-190. [9] Cockell, C. S., Catling, D. C., Davis, W. L., Snook, K., Kepner, R. L., Lee, P., and McKay, C. P. (2000). The ultraviolet environment of Mars: biological implications past, present, and future. Icarus, 146(2), 343-359.

In this contribution, new data concerning bryophytes, fungi, and lichens of the Italian flora are presented. It includes new records and confirmations for the bryophyte generaAneura,Aulacomnium,Dumortiera,Fossombronia,Hennediella,Hygrohypnella,Pohlia,Porella,Riccardia,Tortella, andTortula, the fungal generaCortinarius,Mycena,Naucoria,Trichoglossum, andTubariaand the lichen generaAgonimia,Blastenia,Chaenotheca,Cladonia,Endocarpon,Gyalecta,Lecanographa,Parmeliella,Porpidia,Stenhammarella, andThelidium.

We explored the influence of climatic factors on diversity patterns of multiple taxa (lichens, bryophytes, and vascular plants) along a steep elevational gradient to predict communities’ dynamics under future climate change scenarios in Mediterranean regions. We analysed (1) species richness patterns in terms of heat-adapted, intermediate, and cold-adapted species; (2) pairwise beta-diversity patterns, also accounting for its two different components, species replacement and richness difference; (3) the influence of climatic variables on species functional traits. Species richness is influenced by different factors between three taxonomic groups, while beta diversity differs mainly between plants and cryptogams. Functional traits are influenced by different factors in each taxonomic group. On the basis of our observations, poikilohydric cryptogams could be more impacted by climate change than vascular plants. However, contrasting species-climate and traits-climate relationships were also found between lichens and bryophytes suggesting that each group may be sensitive to different components of climate change. Our study supports the usefulness of a multi-taxon approach coupled with a species traits analysis to better unravel the response of terrestrial communities to climate change. This would be especially relevant for lichens and bryophytes, whose response to climate change is still poorly explored.

Climate change is already causing considerable reductions in biodiversity in all terrestrial ecosystems. These consequences are expected to be exacerbated in biomes that are particularly exposed to change, such as those in the Mediterranean, and in certain groups of more sensitive organisms, such as epiphytic lichens. These poikylohydric organisms find suitable light and water conditions on trunks under the tree canopy. Despite their small size, epiphytic communities contribute significantly to the functionality of forest ecosystems. In this work, we surveyed epiphytic lichen communities in a Mediterranean area (Sardinia, Italy) and hypothesized that 1) the effect of microclimate on lichens at tree scale is mediated by the functional traits of these organisms and that 2) micro-refuge trees with certain morphological characteristics can mitigate the negative effects of future climate change. Results confirm the first hypothesis, while the second is only partially supported, suggesting that the capability of specific trees to host specific conditions may not be sufficient to maintain the diversity and ecosystem functionality of lichen communities in the Mediterranean.

Lichens are symbiotic organisms sensitive to climate change and susceptible to a severe decline in diversity, especially in high elevation environments that are already threatened. In this study, we focused on water-energy relationships derived from climatic variables and phylogenetic diversity indices of terricolous lichen communities occurring on a representative Mediterranean mountain. We hypothesized that the variation of precipitation and temperature and their interaction along the altitudinal gradient will shape the phylogenetic diversity and structure of lichen communities. Our results reveal that dry and arid conditions lead to a strong loss in phylogenetic diversity with consequent impoverishment of high elevation lichen communities under a climate change scenario. The interaction between variables, reflecting water-energy relationships with phylogenetic and community diversity patterns, suggests that in a future climate change scenario, the novel climatic conditions may reduce the capability of the species to survive harsher conditions, and Mediterranean mountains may face a severe loss of genetic diversity in a climate change scenario.

Microclimatic conditions are important in determining lichen distribution at small scale, and may determine whether the species persist when the surrounding environmental conditions have drastically changed. This is the case with forest management, since a sudden variation of microclimatic conditions (increase of solar radiation, temperature, wind and a reduction of humidity) may occur after logging. In this study, the combined effect of forest logging and microclimatic conditions on the growth probabilities and growth rates of the model species

Terricolous lichens, threatened in many areas of Europe, have been greatly overlooked in conservation policies. This work provides a provisional Red List of the terricolous lichens of Italy, to favour their inclusion in conservation policies. The taxa were assigned to IUCN categories according to a simplified assessment procedure based on their rarity and past/current distribution in the administrative regions and ecoregions of Italy. We evaluated 162 species: 30 were listed as regionally extinct, 22 critically endangered, 16 endangered, 49 vulnerable, 27 near-threatened, 7 least-concern, and 11 data deficient. A quarter of the terricolous lichens of Italy is likely to be threatened, but a rigorous assessment is hindered by the scarcity of data. Further field work is needed for more precise assessments of their conservation status.

One of the main topics of astrobiology is the study of life limits in stressful environments. This field of research has the aim to understand the physiological and biochemical effects on unprotected biological samples in extreme conditions, such as space. Moreover, these studies provide indications about organisms’ adaptive plasticity under a climate change perspective, the terrestrial geological past and future scenarios, as well as extra-terrestrial habitats as Mars surface. The biological specimen chosen for this study was Xanthoria parietina (L.) Th. Fr. It is a widespread foliose lichen growing on bark and rocks which has a broad spectrum of tolerance to air pollutants such as NOX and heavy metals, and resistance to UV-radiation because of the screening properties provided by the secondary metabolism product parietin. In this study we evaluated the ability of this lichen specie to survive under simulated UV space radiation in two different extreme environments i.e., in N2 atmosphere (N2) and in vacuum (100~10-2 Pa) (VAC). Thalli of X. parietina were randomly collected in a remote area of Tuscany, Italy in June and July 2020. Thalli were dehydrated for 24 h at room temperature (25°C) and stored at -18°C until treatment. Three days before the treatment, thalli were allowed to recover their normal metabolic conditions in a growth chamber at 25 °C and 70 μmol m-2 s-1 PAR photons. Overnight, thalli were covered with a black cotton cloth and kept moistened by spraying with distilled water. The simulated UV space radiation was produced using a Xe-enhanced UV lamp with a sun-like emission spectrum (wavelength range 185-2000 nm). The aforementioned atmospheric conditions (N2 and VAC) were chosen to set up an extreme and dehydrating environment for the lichen. The total absorbed UV radiation dose was 1.34 MJ m-2 for each exposed sample. During the irradiation, the IR reflectance spectrum of the lichen was monitored in situ with infrared spectroscopy to assess changes in spectral bands. The efficiency of the photosynthetic apparatus was assessed as indicator of vitality, and was expressed in terms of chlorophyll a fluorescence (FV/FM) and Normalized Difference Vegetation Index (NDVI). The examination of X. parietina recovery through eco-physiological analysis revealed the capacity of this lichen species to survive in extreme conditions such as those simulated in this investigation. It has been highlighted the significant difference between treatments about the photosynthetic efficiency parameters recovery trends, finding that UV-radiation in vacuum produces more intense effects on FV/FM values. After 72h, UV N2 fluorescence mean values recovered up to 93% of the starting ones, while UV VAC fluorescence recovered up to 45% of the pre-exposure values. The IR analysis revealed several spectral band changes in the fingerprint region. The most visible variation was the 5200 cm-1 water band, disappearing in the overtone region. This analysis suggests that the disappearance of H2O band after treatment is strictly linked to the thalli dehydration due to the atmospheric simulated conditions represented by N2 insufflation and high vacuum application. Nevertheless, X. parietina was able to survive to UV-radiation in N2 atmosphere and in vacuum, and for this reason it may be considered a candidate for further evaluations on its survival capacity in extreme conditions.

According to the insurance hypothesis, high taxonomic diversity should ensure ecosystem stability because of functional redundancy, whereas reduced functional diversity that results from species loss should affect ecosystem sensitivity, resilience, and vulnerability. However, even in species-rich ecosystems, functional over-redundancy (FOR; i.e., the tendency of most species to cluster into a few over-represented functional entities) in some cases may result in under-representation of many functions, and the ecosystem might become highly vulnerable. Using a stratified random sampling design with nested spatial levels (nine land use strata, 70 plots, 435 trees/rock outcrops, and 9845 quadrats), we recorded the occurrence of over 350 species of epiphytic and rock-dwelling lichens in semi-arid ecosystems in western Sardinia, where solar radiation defines a wide environmental gradient. By accounting for species functional traits, such as growth form, photosynthetic strategies, and reproductive strategies, we obtained 43 functional entities (>60% of all possible combinations) and tested the scale-dependency of FOR and functional vulnerability (FV, i.e., the risk of losing functional entities) by generalized linear mixed models. We found that FOR increased and FV decreased with increasing spatial scale, which supports the hypothesis of a cross-scale functional reinforcement. Decoupling of FOR and FV was far more evident for rock-dwelling compared with epiphytic communities, which reflects differing environmental conditions associated with substrate type. Our results indicate that increased warming and climatic extremes could exacerbate species clustering into the most resistant functional entities and thus enhance FOR at the community level. Therefore, high taxonomic diversity may not ensure systematic buffering of climate change impacts.

In the Mediterranean basin, coastal dune systems are a priority habitat for nature conservation. Seirophora villosa is strictly associated with undisturbed dune juniper formations and can be used as an indicator of the status of conservation. Light regime and water availability are generally the main ecological factors modified by habitat fragmentation that can be detrimental to the colonisation and survival of S. villosa populations in coastal dunes. This study aims to investigate how light regime and water availability affect individual specimens of S. villosa, by studying the relationship between photosynthetic activity and water content per thallus area in different sized S. villosa thalli and comparing susceptibility of hydrated and desiccated thalli to light stress. During dehydration, photosynthetic activity decreased, reaching low constant values in smaller thalli more quickly than in larger ones. During the exposure of dry thalli to high light, photoinhibition consistently occurred earlier in smaller specimens than in larger ones. Moreover, larger thalli that were kept dried recovered to pre-treatment values within 3 days, while smaller ones took 5 days to recover initial values. On the other hand, both large and small wet thalli were photoinhibited within 1 day and recovered to pre-treatment values within 4 and 6 days respectively. Our results showed that S. villosa thalli are susceptible to sudden increases in light exposure, especially in the case of small specimens, which after photoinhibition exhibited a reduced ability to recover. Habitat fragmentation therefore represents a significant threat to the species, particularly in dispersal and establishment phases.

Biological invasions represent a global threat to biodiversity. Particular attention should be devoted to the management of alien plants, focusing on the opportunity to obtain a rapid respo...

Lichens are poikilohydric organisms resulting from the symbiosis between a fungus and a population of green algae and/or cyanobacteria. Their vital functions strictly depend both on exchanges with the atmosphere and on the chemical and physical characteristics of their substrate. Because of the fragile balance to which they are subjected, many species have suffered a considerable decline in their abundance and distribution in recent decades. Moreover, most models predict a worsening of their declines as a direct and indirect consequence of global change. In the face of this worrying picture, lichen conservation policies and actions are still largely insufficient to mitigate lichen biodiversity loss in the near future. In this presentation, we will review some of the key issues in this regard, including: (i) the insufficient level of knowledge of the distribution of most species, due to the lack of large-scale surveys, the difficulty of taxonomic identification and the poor detectability of many groups with small thalli and (ii) The almost total lack of consideration of lichen species in national and international legislation on the conservation of biodiversity. Perspective for more effective conservation will also be outlined on the basis of specific studies, aimed at finding some operational tools to counteract the loss of lichen biodiversity before knowing it.

International audience; Climate change is expected to strongly impact biodiversity in Alpine ecosystems and species distribution modelling is increasingly used to provide anticipatory information to guide conservation. In this study, (1) we quantified the range loss, range gain, range change and range turnover caused by climate change in the genus Peltigera a group of terricolous lichens widespread across the Alps, and then (2) we evaluated the relationships between the predictors of range dynamics and functional traits. Our results indicate moderate range dynamics for species of the genus Peltigera across the Alps under a climate change scenario. This would imply a relative stability and resistance of these lichens to climate change that may reflect the local persistence of the species under sub-optimal conditions. Our results also suggest that range dynamics could be associated with functional traits mainly related to water-use strategies and to a trade-off between dispersal and establishment ability. This finding suggests that functional traits may strongly modulate the lichen response to climate change and that species with similar functional traits are prone to similar selective pressures.

Terricolous lichen communities in lowlands occur especially in open dry habitats. Such communities are often dominated by species of the genus Cladonia, which are very variable in morphology, reproduction strategies, and secondary metabolites. In this work, we investigated traits-environment relationships considering vegetation dynamics, substrate pH, disturbance, and climate. A total of 122 plots were surveyed in 41 acidic dry grasslands in the western Po Plain (Northern Italy). Relationships between Cladonia traits and environmental variables were investigated by means of a model-based Fourth Corner Analysis. Thallus morphology and metabolites responded to vegetation dynamics, substrate pH, disturbance, and climate, whereas reproduction strategies responded only to vegetation dynamics. Traits’ correlations with vegetation dynamics elucidate their colonization patterns in open dry habitats or suggest biotic interactions with bryophytes and vascular plants. In addition, correlations between metabolites and environmental factors support interpretations of their ecological roles. Our results also stress the importance of studying traits’ relationships with climatic factors as an alert towards lichen reactions to climate change.

Recent molecular studies on Parmelia revealed several new semi-cryptic and cryptic species, suggesting the existence of considerable genetic diversity within this genus that may not yet be expressed at the phenotypic level. This is the case of the two species Parmelia ernstiae and P. serrana that have been described in the P. saxatilis group from Europe and that are still poorly known in Italy. The main aim of this study is to shed light into the Italian distribution of these cryptic species on the basis of a systematic and taxonomic revision of exiccata and new specimens of the Parmelia saxatilis group collected along a biogeographical gradient through the Italian peninsula. In this revision, we combined morphological, chemical, and molecular data and evaluated their reliability for identification at the species level. Results indicate that P. saxatilis is the most widespread species and that P. ernstiae is much more widespread than previously thought. In contrast, P. serrana seems to be a rare species in Italy. Our results also indicate that the combined use of morphological and chemical data does not provide a reliable tool to discriminate the cryptic species of this group and that molecular data are thus indispensable for identification at the species level. Finally, our phylogenetic analysis supports the existence of an unrecognized diversity in parmelioid lichens that should be further investigated.

Community ecology has experienced a major transition, from a focus on patterns in taxonomic composition, to revealing the processes underlying community assembly through the analysis of species functional traits. The power of the functional trait approach is its generality, predictive capacity such as with respect to environmental change, and, through linkage of response and effect traits, the synthesis of community assembly with ecosystem function and services. Lichens are a potentially rich source of information about how traits govern community structure and function, thereby creating opportunity to better integrate lichens into ‘mainstream’ ecological studies, while lichen ecology and conservation can also benefit from using the trait approach as an investigative tool. This paper brings together a range of author perspectives to review the use of traits in lichenology, particularly with respect to European ecosystems from the Mediterranean to the Arctic-Alpine. It emphasizes the types of traits that lichenologists have used in their studies, both response and effect, the bundling of traits towards the evolution of life-history strategies, and the critical importance of scale (both spatial and temporal) in functional trait ecology.

Italy is among the European countries with the greatest plant diversity due to both a great environmental heterogeneity and a long history of man–environment interactions. Trait-based approaches to ecological studies have developed greatly over recent decades worldwide, although several issues concerning the relationships between plant functional traits and the environment still lack sufficient empirical evaluation. To draw insights on the association between plant functional traits and direct and indirect human and natural pressures on the environmental drivers, this article summarizes the existing knowledge on this topic by reviewing the results of studies performed in Italy adopting a functional trait approach on vascular plants, bryophytes and lichens. Although we recorded trait measurements for 1418 taxa, our review highlighted some major gaps in plant traits knowledge: Mediterranean ecosystems are poorly represented; traits related to belowground organs are still overlooked; traits measurements for bryophytes and lichens are lacking. Finally, intraspecific variation has been little studied at community level so far. We conclude by highlighting the need for approaches evaluating trait–environment relationship at large spatial and temporal scales and the need of a more effective contribution to online databases to tie more firmly Italian researchers to international scientific networks on plant traits.

In this chapter, the main ecological factors that characterize the epiphyte environ- 7 ment and which determine the composition of epiphyte communities have been 8 described. In particular, emphasis has been made to focus on epiphytic lichens 9 which, due to their ecophysiological characteristics, represent a set of highly 10 specialized organisms that live in a delicate balance in this habitat. The main 11 threats that threaten their survival have been analysed along with the conservation 12 actions that have been undertaken to ensure the maintenance of the populations of 13 the most endangered species have been reviewed. Furthermore, some good 14 practices are suggested that can guarantee greater success of future protection 15 actions.

Despite that congruence across taxa has been proved as an effective tool to provide insights into the processes structuring the spatial distribution of taxonomic groups and is useful for conservation purposes, only a few studies on cross-taxon congruence focused on freshwater ecosystems and on the relations among vascular plants and lichens. We hypothesized here that, since vascular plants could be good surrogates of lichens in these ecosystems, it would be possible to assess the overall biodiversity of riparian habitats using plant data only. In this frame, we explored the relationship between (a) species richness and (b) community composition of plants and lichens in a wetland area located in central Italy to (i) assess whether vascular plants are good surrogates of lichens and (ii) to test the congruence of patterns of species richness and composition among plants and lichens along an ecological gradient. The general performance of plant species richness per se, as a biodiversity surrogate of lichens, had poor results. Nonetheless, the congruence in compositional patterns between lichens and vascular plants varied across habitats and was influenced by the characteristics of the vegetation. In general, we discussed how the strength of the studied relationships could be influenced by characteristics of the data (presence/absence vs. abundance), by the spatial scale, and by the features of the habitats. Overall, our data confirm that the more diverse and structurally complex the vegetation is, the more diverse are the lichen communities it hosts.

In the present study, mercury (Hg) concentrations were investigated in lichens (Flavoparmelia caperata (L.) Hale, Parmelia saxatilis (L.) Ach., and Xanthoria parietina (L.) Th.Fr.) collected in the surrounding of the dismissed Abbadia San Salvatore Hg mine (Monte Amiata district, Italy). Results were integrated with Hg concentrations in tree barks and literature data of gaseous Hg levels determined by passive air samplers (PASs) in the same area. The ultimate goal was to compare results obtained by the three monitoring techniques to evaluate potential mismatches. Lichens displayed 180–3600 ng/g Hg, and Hg concentrations decreased exponentially with distance from the mine. Mercury concentration was lower than in Pinus nigra barks at the same site. There was a moderate correlation between Hg in lichen and Hg in bark, suggesting similar mechanisms of Hg uptake and residence times. However, correlation with published gaseous Hg concentrations (PASs) was moderate at best (Kendall Tau = 0.4–0.5, p > 0.05). The differences occurred because a) PASs collected gaseous Hg, whereas lichens and barks also picked up particulate Hg, and b) lichens and bark had a dynamic exchange with the atmosphere. Lichen, bark, and PAS outline different and complementary aspects of airborne Hg content and efficient monitoring programs in contaminated areas would benefit from the integration of data from different techniques.

We studied the secondary succession in semi-natural grasslands (dry grasslands and hay meadows) located in the eastern side of the Tuscan Apennines (Tuscany, Central Italy). We compared these habitats, investigating: (i) the changes in species richness, composition and phylogenetic diversity during the succession; (ii) whether the trends in species loss and species turnover in taxonomic diversity matched those in phylogenetic diversity. We performed a stratified random sampling, in a full factorial design between habitat type and succession stage (60 sampled plots, 10 × 2 types of habitat × 3 stages of succession). We constructed a phylogenetic tree of the plant communities and compared the differences in taxonomic/phylogenetic α- and β-diversity between these two habitats and during their succession. We identified indicator species for each succession stage and habitat. Looking at α-diversity, both habitats displayed a decrease in species richness, with a random process of species selection in the earlier succession stages from the species regional pool. Nevertheless, in the latter stage of dry grasslands we recorded a shift towards phylogenetic overdispersion at the higher-level groups in the phylogenetic tree. In both habitats, while the richness decreased with succession stage, most species were replaced during the succession. However, the hay meadows were characterized by a higher rate of new species’ ingression whereas the dry grasslands became dominated with Juniperus communis. Accordingly, the two habitats showed similar features in phylogenetic β-diversity. The main component was true phylogenetic turnover, due to replacement of unique lineages along the succession. Nevertheless, in dry grasslands this trend is slightly higher than expected considering the major importance of difference in species richness of dry grasslands sites and this is due to the presence of a phylogenetically very distant species (J. communis).

Characterizing functional trait variation and covariation, and its drivers, is critical to understand the response of species to changing environmental conditions. Evolutionary and environmental factors determine how traits vary among and within species at multiple scales. However, disentangling their relative contribution is challenging and a comprehensive trait–environment framework addressing such questions is missing in lichens. We investigated the variation in nine traits related to photosynthetic performance, water use and nutrient acquisition applying phylogenetic comparative analyses in lichen epiphytic communities on beech across Europe. These poikilohydric organisms offer a valuable model owing to their inherent limitations to buffer contrasting environmental conditions. Photobiont type and growth form captured differences in certain physiological traits whose variation was largely determined by evolutionary processes (i.e. phylogenetic history), although the intraspecific component was non-negligible. Seasonal temperature fluctuations also had an impact on trait variation, while nitrogen content depended on photobiont type rather than nitrogen deposition. The inconsistency of trait covariation among and within species prevented establishing major resource use strategies in lichens. However, we did identify a general pattern related to the water-use strategy. Thus, to robustly unveil lichen responses under different climatic scenarios, it is necessary to incorporate both among and within-species trait variation and covariation.

Assessing the ecological impacts of environmental change on biological communities requires knowledge of the factors driving the spatial patterns of the three diversity facets along extensive environmental gradients. We quantified the taxonomic (TD), functional (FD), and phylogenetic diversity (PD) of lichen epiphytic communities in 23 beech forests along Europe to examine their response to environmental variation (climate, habitat quality, spatial predictors) at a continental geographic scale. We selected six traits related to the climatic conditions in forest ecosystems, the water-use strategy and the nutrient uptake, and we built a phylogenetic tree based on four molecular markers. FD and climate determined TD and PD, with spatial variables also affecting PD. The three diversity facets were primarily shaped by distinct critical predictors, with the temperature diurnal range affecting FD and PD, and precipitation of the wettest month determining TD. Our results emphasize the value of FD for explaining part of TD and PD variation in lichen communities at a broad geographic scale, while highlighting that these diversity facets provide complementary information about the communities&rsquo, response under changing environmental conditions. Furthermore, traits such as growth form, photobiont type, and reproductive strategy mediated the response of lichen communities to abiotic factors emerging as useful indicators of macroclimatic variations.

International audience; While changing climatic conditions may directly impact species distribution ranges, indirect effects related to altered biotic interactions may exacerbate range shifts. This situation fully applies to epiphytic lichens that are sensitive to climatic factors and strongly depend on substrate occurrence and features for their dispersal and establishment. In this work, we modelled the climatic suitability across Italy under current and future climate of the forest species Lobaria pulmonaria, the lung lichen. Comparatively, we modelled the suitability of its main tree species in Italy, as well as that of the alien tree Robinia pseudoacacia, black locust, whose spread may cause the decline of many forest lichen species. Our results support the view that climate change may cause range shifts ofepiphytes by altering the spatial pattern of their climatic suitability (direct effect) and simultaneously causing range shifts of their host-tree species (indirect effect). This phenomenon seems to be emphasized by the invasion of alien trees, as in the case of black locust, that may replace native host tree species. Results indicate that a reduction of the habitat suitability of the lung lichen across Italy should be expected in the face of climate change and that this is coupled with aloss of suitable substrate. This situation seems to be determined by two main processes that act simultaneously: 1) a partial reduction of the spatial overlap between the climatic niche of the lung lichen and that of its host tree species, and 2) the invasion of native woods by black locust. The case of lung lichen and black locust in Italy highlights that epiphytes are prone to both direct and indirect effects of climate change. The invasion of alien trees may have consequences that are still poorly evaluated for epiphytes.