Similarly to other Mediterranean regions, Italy is expected to experience dramatic climatic changes in the coming decades. Do to their poikilohydric nature, lichens are among the most sensitive ...organisms to climate change and species requiring temperate-humid conditions may rapidly decline in Italy, such in the case of the epiphytic Lobaria species that are confined to humid forests. Our study, based on ecological niche modelling of occurrence data of three Lobaria species, revealed that in the next decades climate change will impact their distribution range across Italy, predicting a steep gradient of increasing range loss across time slices. Lobaria species are therefore facing a high extinction risk associated with reduction of their range. The current patterns indicate that only L. pulmonaria still has a continuous distribution across Italy, with potential contact between Apennine and Alpine populations. This situation is consistent with the wider climatic niche of this species, still offering a major opportunity for its successful long-term conservation. Results (a) support the inclusion of the three Lobaria species in European conservation policies, such as the Habitat Directive, and (b) warn against an over-estimation of the indicator power of single flagship species to establish conservation priorities for lichens, indicating that even lichens with peculiar and similar climatic envelopes may fail to co-occur within a given forest stand. A multiple indicator approach could provide more useful tools for a community-based conservation strategy for epiphytes.
•Lichens are among the most sensitive organisms to climate change.•Climate change will impact the distribution range of Lobaria species across Italy.•Lobaria species are facing extinction risk due to range reduction.•Lobaria species should be included in European conservation policies.•A multiple indicator approach could support conservation priorities for lichens.
While higher plant communities found on ultramafics are known to display peculiar characteristics, the distinguishability of any peculiarity in lichen communities is still a matter of contention. ...Other biotic or abiotic factors, rather than substrate chemistry, may contribute to differences in species composition reported for lichens on adjacent ultramafic and non-ultramafic areas. This work examines the lichen biota of ultramafics, at global and regional scales, with reference to species-specific functional traits. An updated world list of lichens on ultramafic substrates was analyzed to verify potential relationships between diversity and functional traits of lichens in different Köppen–Geiger climate zones. Moreover, a survey of diversity and functional traits in saxicolous communities on ultramafic and non-ultramafic substrates was conducted in Valle d’Aosta (North-West Italy) to verify whether a relationship can be detected between substrate and functional traits that cannot be explained by other environmental factors related to altitude. Analyses (unweighted pair group mean average clustering, canonical correspondence analysis, similarity-difference-replacement simplex approach) of global lichen diversity on ultramafic substrates (2314 reports of 881 taxa from 43 areas) displayed a zonal species distribution in different climate zones rather than an azonal distribution driven by the shared substrate. Accordingly, variations in the frequency of functional attributes reflected reported adaptations to the climate conditions of the different geographic areas. At the regional scale, higher similarity and lower species replacement were detected at each altitude, independent from the substrate, suggesting that altitude-related climate factors prevail over putative substrate–factors in driving community assemblages. In conclusion, data do not reveal peculiarities in lichen diversity or the frequency of functional traits in ultramafic areas.
Both the indirect control of microclimate conditions and the direct application of preservative products to contrast stone bioreceptivity may contribute to limit lithobiontic recolonization of ...cultural heritage surfaces after cleaning interventions. However, the priority deserved by these different preventive approaches has still been poorly evaluated, particularly in outdoor environments. This work dealt with the engraved sandstone surfaces of the National Park of Rock Engravings of Naquane (Italy, UNESCO WHS), widely colonized by lichens, mosses and a dark cyanobacterial biofilm, and thus requiring frequent cleaning interventions to preserve their legibility for visitors and scholars. In particular, post-cleaning recolonization by the different lithobionts was seasonally monitored along 54 months in different zones of an engraved outcrop, primarily differing in levels of shading, on parcels exposed to nine different conservative treatments. These included (or not) a pre-cleaning devitalization of lithobionts and the post-cleaning application of biocidal (benzalkonium chloride, plant essential oils, usnic acid) and other restoration products (nanocrystalline anatase, polysiloxane-based water repellent, ethyl-silicate-based consolidant). The combination of surface image analyses, fluorimetric and colorimetric measurements showed that mosses and the cyanobacterial biofilm rapidly recolonized all the parcels in the more shaded zone, irrespective of conservative treatments. In the other areas, recolonization significantly differed depending on the treatment. The post-cleaning application of biocides determined the best results through two vegetative seasons, but only nanocrystalline anatase and the polysiloxane-based water repellent maintained the surfaces lighter than uncleaned controls along the whole monitoring period. Recolonization primarily proceeded by the uncleaned surfaces surrounding the parcels and, at least in the examined case of lichens, did not show substantial shifts in community composition, although some nitrophytic species increased their frequency. In conclusion, the effectiveness of preservative treatments to prevent a rapid recolonization of heritage stone surfaces appeared subordinate to the presence of microenvironmental conditions less favourable to lithobionts.
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•Biofilms, mosses and lichens monitored by image analysis, fluorimetry and colorimetry.•Effectiveness of preservative treatments dependent on microenvironmental conditions•Lowest after cleaning re-darkening with polysiloxane water repellent and nano-anatase•Delayed recolonization also with the application of synthetic and natural biocides•No change in lichen diversity but increased nitrophytic species after some treatments.
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 genera
Diplophyllum
and
...Ptychostomum
, the fungal genera
Arrhenia
,
Gymnosporangium
, and
Sporidesmium
and the lichen genera
Arthonia
,
Coenogonium
,
Flavoplaca
,
Gyalolechia
,
Parmotrema
,
Peltigera
,
Pterygiopsis
,
Squamarina
,
Tornabea
, and
Waynea
.
Asbestos exposure has been linked to adverse human health effects including asbestosis and mesothelioma. As such, mining and utilization of asbestos is restricted or has been banned in about 50 ...countries since 1990. Nevertheless, abandoned asbestos mines, mostly in serpentine areas, persist as sources of hazardous airborne fibers. Revegetation of asbestos mine spoils has been proposed as a way by which to stabilize asbestos-bearing substrate, thereby reducing fiber dispersion into the air. No study to date, however, has evaluated the revegetation's effectiveness of reducing airborne asbestos pollution. In this study, we evaluated the effect of natural revegetation on the air dispersion of asbestos fibers from asbestos-rich serpentine lithosoils at an abandoned chrysotile mine. Air sampling of vegetated and barren plots within the mine demonstrated that vegetative cover significantly reduced asbestos dispersion into the air (50% reduction with 15–40% vegetative cover). Additionally, the effectiveness of several native, locally collected serpentine-tolerant species to revegetate the asbestos mine spoil, including Minuartia and Thymus species, was evaluated. Mat-forming, serpentine endemic Thymus sp. proved to be particularly effective at revegetating the mine spoil, having high transplantation survival, growth rates, and reproductive output.
This work analyzed the influence of different application protocols on the efficacy of two biocides against the foliose lichen Xanthoparmelia tinctina on the sandstones of the Roman Archaeological ...site of Luni (Italy). The hypotheses that (a) biocide application tools (brush vs. poultice), (b) pre-treatment hydration, and (c) post-treatment washing may affect devitalization success were verified by monitoring chlorophyll a fluorescence of thalli, both in situ and in laboratory conditions. The hypothesis that (d) stone substrate may act as reservoir for later biocide release under repeated cycles of wetting and drying was also assayed. Analyses confirmed the importance of the application tool, with cellulose poultice being more effective than brush. Hydration influenced the biocide absorption by thalli. Moreover it modulated the metabolic activity and susceptibility to the available toxic compound, hindering lichens from entering a dormant state to tolerate stress. Depending on the preparation solvent (water vs. white spirit), the biocide application benefited from pre-treatment hydration and/or a post-treatment washing. Lastly, we showed that different sandstones variously adsorb the biocides and potentially contribute as a reservoir for their long-term release at low concentrations during successive hydration events.
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•The protocol to apply biocides on lichens affects the devitalization effects.•Cellulose poultice application of biocides is more effective than that by brush.•Pre-hydration and/or post-washing of thalli regulate biocide effectiveness.•The stone substrate acts as a reservoir for long-term release of biocide.•Effective application protocols can limit useless chemical release to the environment.
Control of lichens on stone cultural heritage is mostly achieved by a combination of mechanical removal with biocide applications. However, there is a lack of scientific evidence on the efficacy of ...different biocides on different species, and on the consistency of biocide effects on heritage sites in different environmental conditions. This results in some uncertainty when conservation interventions to control lichens are routinely defined on the basis of restoration tradition or empirical evaluation, without experimental measures of how lichens respond. In this work, we quantitatively evaluated (a) the efficacy of five commercially-available biocides, applied using a brush or with a cellulose poultice, against two species (Protoparmeliopsis muralis, Verrucaria nigrescens), and (b) whether the effects on the two species were consistent, per treatment, across three Italian heritage sites. Lichen vitality was quantified through analyses of chlorophyll a fluorescence (ChlaF) and ergosterol content. The results indicated that all the tested biocides, and their organic solvents, affected the vitality of both the species. However, most of treatments displayed different efficacy on each species, across the different sites and between brush and poultice applications. Accordingly, when a conservation intervention to control lichen growth is planned, biocide treatments need both species- and site-specific calibrations and lichen vitality should be properly ascertained in situ by monitoring ChlaF parameters (FV/FM and F0) twenty days after trial biocide applications.
•A species-specific and site-dependent biocide efficacy is quantified.•Poultice applications affect lichens more severely than brush applications.•Organic solvents used to apply biocides significantly devitalize lichens.•ChlaF measures (Fv/FM, F0) highlight specific patterns of residual vitality in thalli.•Conservative interventions need ad-hoc calibrations of biocide treatments on lichens.
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