Survival in nunatak and peripheral glacial refugia of three alpine plant species is partly predicted by altitudinal segregation.

Mountain biota survived the Quaternary cold stages most probably in peripheral refugia and/or ice-free peaks within ice-sheets (nunataks). While survival in peripheral refugia has been broadly demonstrated, evidence for nunatak refugia is still scarce. We generated RADseq data from three mountain plant species occurring at different elevations in the southeastern European Alps to investigate the role of different glacial refugia during the Last Glacial Maximum (LGM). We tested the following hypotheses. (i) The deep Piave Valley forms the deepest genetic split in the species distributed across it, delimiting two peripheral refugia. (ii) The montane to alpine species Campanula morettiana and Primula tyrolensis survived the LGM in peripheral refugia, while high-alpine to subnival Saxifraga facchinii likely survived in several nunatak refugia. (iii) The lower elevation species suffered a strong population decline during the LGM. By contrast, the higher elevation species shows long-term stability of population sizes due to survival on permanently ice-free peaks and small population sizes at present. We found peripheral refugia on both sides of the Piave Valley, which acted as a major genetic barrier. Demographic modelling confirmed nunatak survival not only for S. facchinii but also for montane to alpine C. morettiana. Altitudinal segregation influenced the species' demographic fluctuations, with the lower elevation species showing a significant population increase at the end of the LGM, and the higher elevation species either showing decrease towards the present or stable population sizes with a short bottleneck. Our results highlight the role of nunatak survival and species ecology in the demographic history of mountain species.

The Dolichens database: the lichen biota of the Dolomites.

The Dolichens project provides the first dynamic inventory of the lichens of the Dolomites (Eastern Alps, Italy). Occurrence records were retrieved from published and grey literature, reviewed herbaria, unpublished records collected by the authors, and new sampling campaigns, covering a period from 1820 to 2022. Currently, the dataset contains 56,251 records, referring to 1,719 infrageneric taxa, reported from 1820 to 2022, from hilly to nival belts, and corresponding to about half of the species known for the whole Alpine chain. Amongst them, 98% are georeferenced, although most of them were georeferenced a posteriori. The dataset is available through the Global Biodiversity Information Facility (GBIF; https://www.gbif.org/es/dataset/cea3ee2c-1ff1-4f8e-bb37-a99600cb4134) and through the Dolichens website (https://italic.units.it/dolichens/). We expect that this open floristic inventory will contribute to tracking the lichen diversity of the Dolomites over the past 200 years, and providing the basis for future taxonomic, biogeographical, and ecological studies.

Botanical memory: five centuries of floristic changes revealed by a Renaissance herbarium (Ulisse Aldrovandi, 1551-1586).

We analysed the spatially explicit floristic information available in the herbarium of Ulisse Aldrovandi (1551-1586) to track floristic changes in the surroundings of Bologna across five centuries. Aldrovandi's data were compared with the Flora della Provincia di Bologna by Girolamo Cocconi (1883) and the Floristic Database of Emilia-Romagna (1965-2021). We explored potential variations in native range and life forms composition, and habitat affinity of the species in the three floras, also contrasting between native and alien species. Native species, mainly in terms of variations of hydro-hygrophytes, chamaephytes and therophytes, provide clear signals of human disturbance and habitat loss. Signals of climate change are provided by the high-mountain species, that were comparably rare between Aldrovandi and current flora and more represented in Cocconi, probably reflecting the effect of the Little Ice Age. Our findings also indicate the increasing importance of alien species from the Renaissance onwards. In this perspective, Aldrovandi's herbarium preserves the memory of the first signs of a radical transformation of the European flora and habitats. Finally, the study warns about the risk of dismissing herbaria and herbarium specimens collection, which would cause irreparable lacunas in our botanical memory, hindering our ability to predict biodiversity trajectories.

Freshwater Lichens, Including New Species in the Genera Verrucaria, Placopyrenium and Circinaria, Associated with Lobothallia hydrocharis (Poelt & Nimis) Sohrabi & Nimis from Watercourses of Sardinia.

This work summarizes the results of the exploration of freshwater lichen biota on the island of Sardinia associated with the regional flagship species Lobothallia hydrocharis, a large-sized crustose lichen from the splash zone along mountain streams, so far known from Sardinia only. Molecular data were used to confirm its distinctiveness from other taxa and its systematic placement and to identify critical taxa among its associated lichen biota. We found 25 species of lichenized fungi, including three species new to science in the genera Verrucaria, Placopyrenium, and Circinaria, and seven species new to Sardinia (Hydropunctaria rheithrophila, Ionaspis chrysophana, I. odora, Verrucaria aquatilis, V. collematodes, V. pseudovirescens), or new to Southern Europe (V. devensis). Specific traits for the freshwater lichen biota of Sardinia were identified and compared to those reported from freshwater sites in the Alps and Carpathian mountains, e.g., a relative scarcity of subgelatinous lichens. Parasitic or epilichenic interactions were found frequently but only in the splash zone and not in the permanently submerged zone, i.e., two parasitic Placopyrenium species, and clearly lichenicolous thalli of Kuettlingeria atroflava and Lobothallia hydrocharis. Due to its specific trait profile and the great potential for the discovery of new species, we recommend the inclusion of Sardinian and further Mediterranean sites in continental-scale monitoring programs for freshwater lichens.

A research agenda for nonvascular photoautotrophs under climate change.

Nonvascular photoautotrophs (NVP), including bryophytes, lichens, terrestrial algae, and cyanobacteria, are increasingly recognized as being essential to ecosystem functioning in many regions of the world. Current research suggests that climate change may pose a substantial threat to NVP, but the extent to which this will affect the associated ecosystem functions and services is highly uncertain. Here, we propose a research agenda to address this urgent question, focusing on physiological and ecological processes that link NVP to ecosystem functions while also taking into account the substantial taxonomic diversity across multiple ecosystem types. Accordingly, we developed a new categorization scheme, based on microclimatic gradients, which simplifies the high physiological and morphological diversity of NVP and world-wide distribution with respect to several broad habitat types. We found that habitat-specific ecosystem functions of NVP will likely be substantially affected by climate change, and more quantitative process understanding is required on: (1) potential for acclimation; (2) response to elevated CO2 ; (3) role of the microbiome; and (4) feedback to (micro)climate. We suggest an integrative approach of innovative, multimethod laboratory and field experiments and ecophysiological modelling, for which sustained scientific collaboration on NVP research will be essential.

Brassica and Sinapis Seeds in Medieval Archaeological Sites: An Example of Multiproxy Analysis for Their Identification and Ethnobotanical Interpretation.

The genus Brassica includes some of the most important vegetable and oil crops worldwide. Many Brassica seeds (which can show diagnostic characters useful for species identification) were recovered from two archaeological sites in northern Italy, dated from between the Middle Ages and the Renaissance. We tested the combined use of archaeobotanical keys, ancient DNA barcoding, and references to ancient herbarium specimens to address the issue of diagnostic uncertainty. An unequivocal conventional diagnosis was possible for much of the material recovered, with the samples dominated by five Brassica species and Sinapis. The analysis using ancient DNA was restricted to the seeds with a Brassica-type structure and deployed a variant of multiplexed tandem PCR. The quality of diagnosis strongly depended on the molecular locus used. Nevertheless, many seeds were diagnosed down to species level, in concordance with their morphological identification, using one primer set from the core barcode site (matK). The number of specimens found in the Renaissance herbaria was not high; Brassica nigra, which is of great ethnobotanical importance, was the most common taxon. Thus, the combined use of independent means of species identification is particularly important when studying the early use of closely related crops, such as Brassicaceae.

Little time left. Microrefuges may fail in mitigating the effects of climate change on epiphytic lichens.

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.

Microclimatic Alteration after Logging Affects the Growth of the Endangered Lichen Lobaria pulmonaria.

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 Lobaria pulmonaria was assessed in mixed oak stands. To this purpose, 800 fragments of L. pulmonaria (<1 cm) were transplanted in logged and unlogged stands for two years. Young and adult fragments were positioned on Turkey oak boles according to distance from the ground (100 and 50 cm) and aspect (north and south). The results, evaluated by generalized linear mixed models on a yearly basis, highlighted differences in growth-particularly on isolated trees in the logged stand. South-exposed samples in the logged stand showed a low probability of growth, while samples transplanted north in the unlogged stand showed higher growth probabilities. However, the highest annual growth coefficients corresponded to south-exposed samples 50 cm from the ground in the unlogged stand. In general, higher growth rates were observed in young thallus fragments when compared with adult ones. Beyond confirming the importance of microclimate for lichen ecology, these results could be implemented in conservation actions to preserve L. pulmonaria populations in logged forests.

A quantitative review and meta-analysis on phytoscreening applied to aquifers contaminated by chlorinated ethenes.

Applications and acceptance of phytoscreening, i.e., the use of trees as screening tools for underground contamination, are still limited in many countries due to the lack of awareness of application policies, the intrinsic qualitative nature of the technique, and the paucity of critical analyses on available data. To date, the conditions influencing the effectiveness of the technique have been descriptively discussed, yet rarely quantified. This review will contribute to filling this knowledge gap, shedding light on the most suitable approaches to apply phytoscreening. The focus was placed specifically on chlorinated ethene compounds since they are among the main organic contaminants in groundwater and have been the most studied in the field of phytoscreening. Chlorinated ethenes' behavior and biodegradation potential largely depend on their physicochemical properties as well as the hydrogeological features of the system in which they migrate. Besides, their fate and transport in surface ecosystems are still poorly understood. Here, phytoscreening data from sites contaminated by chlorinated ethenes were extracted from relevant literature to form a global-scale database. Data were statistically analyzed to identify the major drivers of variability in tree-cores concentration. Correlation between tree-core and groundwater concentration was quantified through Spearman's rank coefficients, whilst detectability potential was determined based on tree-cores showing non-detection of contaminants. The influence on such parameters of factors like contaminant properties, hydrogeology, tree features, and sampling/analytical protocols was assessed. Results suggest that factors controlling plant uptake and contaminant phytovolatilization regulate correlation and detectability, respectively. Conditions increasing the correlation (e.g., sites with shallow and permeable aquifers) are recommended for phytoscreening applications aimed at mapping and monitoring contaminant plumes, whereas conditions increasing detectability (e.g., sampling tree-cores near ground level) are recommended to preliminary screen underground contamination in poorly investigated areas.

Topography of the Dolomites modulates range dynamics of narrow endemic plants under climate change.

Climate change is expected to threaten endemic plants in the Alps. In this context, the factors that may modulate species responses are rarely investigated at a local scale. We analyzed eight alpine narrow endemics of the Dolomites (southeastern Alps) under different predicted climate change scenarios at fine spatial resolutions. We tested possible differences in elevation, topographic heterogeneity and velocity of climate change among areas of gained, lost, or stable climatic habitat. The negative impact of climate change ranged from moderate to severe, depending on scenario and species. Generally, range loss occurred at the lowest elevations, while gained and stable areas were located at highest elevations. For six of the species, climate change velocity had higher values in stable and gained areas than in lost ones. Our findings support the role of topographic heterogeneity in maintaining climatic microrefugia, however, the peculiar topography of the Dolomites, characterized by high altitude plateaus, resulted in high climate change velocity in areas of projected future climatic suitability. Our study supports the usefulness of multiple predictors of spatio-temporal range dynamics for regional climate-adapted management and eventual assisted colonization planning to not overlook or overestimate the potential impact of climate change locally.

A hotspot of lichen diversity and lichenological research in the Alps: the Paneveggio-Pale di San Martino Natural Park (Italy).

A checklist of 916 lichenised taxa is reported from the Paneveggio-Pale di San Martino Natural Park and its surroundings (Trentino-Alto Adige, N Italy), based on 7351 records from: (a) 72 literature sources, (b) eight public and private herbaria and (c) field observations by some of the authors. The study area appears as a hotspot of lichen diversity, hosting 30.1% of the lichen biota of the Alps in a territory that has 0.064% of their total surface area. This is mainly due to its high climatical, geological and orographic heterogeneity, but also to the long history of lichenological exploration, that started in the 19th century with Ferdinand Arnold and is still ongoing. The present work highlights the importance of detailed species inventories to support knowledge of biodiversity patterns, taxonomy and ecology and to properly address conservation issues. Fuscideamollisvar.caesioalbescens, Hydropunctariascabra, Protoparmeliabadiavar.cinereobadia and Variosporapaulii are new to Italy, 18 other taxa are new to Trentino-Alto Adige.

Lichens as monitors of the atmospheric deposition of potentially toxic elements in high elevation Mediterranean ecosystems.

In this study we used a terricolous lichen (Cetraria islandica) as bioaccumulator of potentially toxic elements (PTEs) to explore spatial patterns of air pollutant deposition along elevational gradients in the Majella Massif (Italy). Samples of C. islandica were collected at 200 m intervals along 6 transects from 1600 to 2600 m, both along the eastern and the western slope of the Majella massif, and analyzed for their PTE content. The results supported the hypothesis that the deposition of PTEs to the Majella massif is largely influenced by elevation and slope. Two main patterns emerged connected either with local soil erosion and long-range atmospheric transport. For some PTEs, namely Al, Cr, Li, Mg, in the absence of any other data, it is supposed that the anthropogenic input is very small compared to the natural input from weathering processes. In contrast, the group of air pollutants subjected to long-range transport, as in the case of Cd, Hg, and Pb, has very limited local input and the main sources responsible for the higher concentrations on the eastern slope are probably to be searched in the Balkan area.

Refining the picture: new records to the lichen biota of Italy.

Based on the analysis of both historical and recent collections, this paper reports an annotated list of taxa which are new to the lichen biota of Italy or of its administrative regions. Specimens were identified using a dissecting and a compound microscope; routine chemical spot tests and standardized thin-layer chromatography (TLC or HPTLC). The list includes 225 records of 153 taxa. Twenty taxa are new to Italy, the others are new to one or more administrative regions, with 15 second records and 5 third records for Italy. Some of the species belong to recently-described taxa, others are poorly known, sterile or ephemeral lichens which were largely overlooked in Italy. Several species are actually rare, either because of the rarity of their habitats (e.g. old-growth forests), or because in Italy they are at the margins of their bioclimatic distribution. The picture of the lichen biota of Italy has now new pixels, but its grain is still coarse. Further analysis of historical collections, increased efforts in the exploration of some areas, and the taxonomic revision of critical groups are still necessary to provide more complete distributional data for new biogeographic hypotheses, taxonomic and ecological research, and biodiversity conservation.

Environmental drivers of forest biodiversity in temperate mixed forests - A multi-taxon approach.

Harmonization of timber production and forest conservation is a major challenge of modern silviculture. For the establishment of ecologically sustainable forest management, the management-related environmental drivers of multi-taxon biodiversity should be explored. Our study reveals those environmental variables related to tree species diversity and composition, stand structure, litter and soil conditions, microclimate, landscape, and land-use history that determine species richness and composition of 11 forest-dwelling organism groups. Herbs, woody regeneration, ground-floor and epiphytic bryophytes, epiphytic lichens, terricolous saprotrophic, ectomycorrhizal, and wood-inhabiting macrofungi, spiders, carabid beetles, and birds were sampled in West Hungarian mature mixed forests. The correlations among the diversities and compositions of different organism groups were also evaluated. Drivers of organism groups were principally related to stand structure, tree species diversity and composition, and microclimate, while litter, soil, landscape, and land-use historical variables were less influential. The complex roles of the shrub layer, deadwood, and the size of the trees in determining the diversity and composition of various taxa were revealed. Stands with more tree species sustained higher stand-level species richness of several taxa. Besides, stands with different dominant tree species harbored various species communities of organism groups. Therefore, landscape-scale diversity of dominant tree species may enhance the diversity of forest-dwelling communities at landscape level. The effects of the overstory layer on forest biodiversity manifested in many cases via microclimate conditions. Diversity of organism groups showed weaker relationship with the diversity of other taxa than with environmental variables. According to our results, the most influential drivers of forest biodiversity are under the direct control of the actual silvicultural management. Heterogeneous stand structure and tree species composition promote the different organism groups in various ways. Therefore, the long-term maintenance of the structural and compositional heterogeneity both at stand and landscape scale is an important aspect of ecologically sustainable forest management.

Functional Traits in Lichen Ecology: A Review of Challenge and Opportunity.

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.

The lichens of the Majella National Park (Central Italy): an annotated checklist.

The botanical exploration of the Majella National Park has a long tradition dating back to the eighteenth century. However, the lichen biota of this area is still poorly investigated. To provide a baseline for future investigations, in this annotated checklist, we summarised all available information on the occurrence of lichens in the Majella National Park, retrieved from previous literature, herbarium material and original data produced by recent research. The checklist includes 342 infrageneric taxa. However, seven taxa are considered as dubious, thus setting the number of accepted taxa at 335, i.e. 45.8% of those currently known to occur in the Abruzzo Region. This checklist provides a baseline of the lichens known to occur in the Majella National Park, highlighting the potential of this area as a hotspot of lichen biodiversity, especially from a biogeographical point of view as indicated by the occurrence of several arctic-alpine species that form disjunct populations in the summit area of the massif.

Morphological and Chemical Traits of Cladonia Respond to Multiple Environmental Factors in Acidic Dry Grasslands.

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.

Contrasting multitaxon responses to climate change in Mediterranean mountains.

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.

Diversity of European habitat types is correlated with geography more than climate and human pressure.

Habitat richness, that is, the diversity of ecosystem types, is a complex, spatially explicit aspect of biodiversity, which is affected by bioclimatic, geographic, and anthropogenic variables. The distribution of habitat types is a key component for understanding broad-scale biodiversity and for developing conservation strategies. We used data on the distribution of European Union (EU) habitats to answer the following questions: (i) how do bioclimatic, geographic, and anthropogenic variables affect habitat richness? (ii) Which of those factors is the most important? (iii) How do interactions among these variables influence habitat richness and which combinations produce the strongest interactions? The distribution maps of 222 terrestrial habitat types as defined by the Natura 2000 network were used to calculate habitat richness for the 10 km × 10 km EU grid map. We then investigated how environmental variables affect habitat richness, using generalized linear models, generalized additive models, and boosted regression trees. The main factors associated with habitat richness were geographic variables, with negative relationships observed for both latitude and longitude, and a positive relationship for terrain ruggedness. Bioclimatic variables played a secondary role, with habitat richness increasing slightly with annual mean temperature and overall annual precipitation. We also found an interaction between anthropogenic variables, with the combination of increased landscape fragmentation and increased population density strongly decreasing habitat richness. This is the first attempt to disentangle spatial patterns of habitat richness at the continental scale, as a key tool for protecting biodiversity. The number of European habitats is related to geography more than climate and human pressure, reflecting a major component of biogeographical patterns similar to the drivers observed at the species level. The interaction between anthropogenic variables highlights the need for coordinated, continental-scale management plans for biodiversity conservation.

The Plot Thickens: Haploid and Triploid-Like Thalli, Hybridization, and Biased Mating Type Ratios in Letharia.

The study of the reproductive biology of lichen fungal symbionts has been traditionally challenging due to their complex lifestyles. Against the common belief of haploidy, a recent genomic study found a triploid-like signal in Letharia. Here, we infer the genome organization and reproduction in Letharia by analyzing genomic data from a pure culture and from thalli, and performing a PCR survey of the MAT locus in natural populations. We found that the read count variation in the four Letharia specimens, including the pure culture derived from a single sexual spore of L. lupina, is consistent with haploidy. By contrast, the L. lupina read counts from a thallus' metagenome are triploid-like. Characterization of the mating-type locus revealed a conserved heterothallic configuration across the genus, along with auxiliary genes that we identified. We found that the mating-type distributions are balanced in North America for L. vulpina and L. lupina, suggesting widespread sexual reproduction, but highly skewed in Europe for L. vulpina, consistent with predominant asexuality. Taken together, we propose that Letharia fungi are heterothallic and typically haploid, and provide evidence that triploid-like individuals are hybrids between L. lupina and an unknown Letharia lineage, reconciling classic systematic and genetic studies with recent genomic observations.