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Functional traits of epiphytic lichens respond to alkaline dust pollution
Abstract
Dust pollution has a harmful impact on the environment and human health. Lichen trait-based metrics are increasingly used to monitor effects of air pollution, but studies using this technique to monitor the effects of dust pollution are still scarce. Functional traits of lichens along a gradient of long-term alkaline dust pollution were investigated. Species composition was affected along this gradient according to two easily identifiable “soft” traits (growth form and main reproductive strategy) and one expert-assessed “hard” trait (species preference for substrate pH). Particularly, crustose species and lichens with sexual reproduction were related to the most polluted side of the gradient and higher pH, while foliose narrow-lobed species and lichens with asexual reproduction were associated with the opposite side.
... The concentration of many air pollutants has decreased throughout Europe during the last decade, but particulate matter (PM) remains above recommended levels (Degtjarenko et al., 2018). Dust pollution is PM consisting of a complex heterogeneous mixture of solid particles suspended in the air ranging between 0.1-10 µm (Degtjarenko et al., 2018). ...
... The concentration of many air pollutants has decreased throughout Europe during the last decade, but particulate matter (PM) remains above recommended levels (Degtjarenko et al., 2018). Dust pollution is PM consisting of a complex heterogeneous mixture of solid particles suspended in the air ranging between 0.1-10 µm (Degtjarenko et al., 2018). Dust pollution usually refers to primary and coarse PM originating from natural or anthropogenic sources. ...
... Dust pollution usually refers to primary and coarse PM originating from natural or anthropogenic sources. Rock quarrying, combustion processes, kiln grinding or roads (friction from brakes and tyres, dust from road surfaces and diesel engines) are the commonest anthropogenic sources (Degtjarenko et al., 2018). These anthropogenic activities release carbon, complex organic chemicals, sulphates, nitrates, mineral dust, and water suspended in the air (Corney et al., 2008). ...
Ancient woodland is a finite resource which cannot be replicated once lost. Pressures from development are varied and not always obvious. Without a thorough understanding of the ecology of individual woodland and trees these pressures are difficult to predict, assess and mitigate. This report reviews evidence, recommends mitigation and management, identifies evidence gaps, and proposes some research properties.
Published by the British Ecological Society (Applied Ecology Resources) at https://www.britishecologicalsociety.org/applied-ecology-resources/document/20210404233/
... Many studies have provided interesting biomonitoring results regarding the relationships between lichen communities' compositions and modeled or measured values of nitrogen and sulfur deposition within forest national monitoring networks in several different European countries (Estonia [44,50], the UK [45], Portugal [46,55], Finland [47], Italy [51], and the USA [40,41,48,49,52,54]). Forests are remote ecosystems of less interest from a risk assessment point of view because of their low population density. However, studying the effects of atmospheric pollution in forest environments may be a good approach for obtaining a reference for the background values in remote areas. ...
... Monitoring of the functional traits of animals, plants, and fungi has increased considerably in recent decades [60]. Concerning epiphytic lichens, functional traits such as growth forms, photosynthetic partners, reproductive strategies, and sensitivity to pollutants (e.g., oligotrophic and nitrophytic species) have been extensively studied in the context of forest monitoring (e.g., [16,44,45,48,50,55]). Here, we consider for discussion only some of the relevant papers on the topic ranging from 1999 to 2021 (Table 2). ...
Currently, forest ecosystems are often located in remote areas, far from direct sources of air pollution. Nonetheless, they may be affected by different types of atmospheric deposition, which can compromise their health and inner balance. Epiphytic lichens respond to air pollution and climate change, and they have been widely adopted as ecological indicators, mainly in urban and industrial areas, while forest ecosystems are still underrepresented. However, in recent years, their use has become increasingly widespread, especially in the context of long-term monitoring programs for air pollution in forests. In this review, we provide a critical analysis of the topic from the point of view of the different methodological approaches based on lichen responses adopted in forest ecosystems. Further, we discuss the main challenges posed by the current global change scenario.
... Paoli et al. (2014) defined Calcium as a good tracer for dust pollution, and lichens as good biomonitors in air pollution around the quarries and the cement plant. Also, influences of long-term dust pollution on lichen diversity and functional traits of lichens (growth form and main reproductive strategy) against long-term dust pollution were investigated by Degtjarenko et al. (2018). In the composition of species, they concluded that crustose species and sexual reproduction were most associated with higher pollution. ...
... The SEM images exhibited several particles on the surface of apothecia in various size and shapes, as well as deformations of thalline surfaces with rough appearance. The deformities seen in the samples are injuries probably caused by air pollutants such as particulate matter or dust in air as mentioned in Degtjarenko et al. (2018). The particles concentrated on both the edges and the discs of apothecia, with the sizes vary up to dimensions exceeding 30 μm. ...
This study is a part of project on biomonitoring the air quality of Isparta province (Turkey) through lichens, and has aimed to assess relation between the amounts of Ca, Mg and Na elements deposited in lichen thalli and the air quality in the area. Lichen samples of Physcia aipolia (Ehrh. ex Humb.) Fürnr. and Xanthoria parietina (L.) Th.Fr. collected from 18 localities in and around Gölcük Nature Park have been investigated in ICP-MS for Ca, Mg and Na. In addition, selected samples of both lichen species from the polluted and non-polluted sites for these three elements were observed by Scanning Electron Microscopy (SEM) micrographs and Energy Dispersion X-Ray Spectroscopy (EDS) analysis. The ratio for elemental contents in the lichen thalli resulted as Mg>Ca>Na for both species, with multiple times higher in X. parietina than P. aipolia. The concentrations of Ca and Mg in the samples were found reversely proportional to the altitude of the localities. Also, it has been observed that some thalline and apothecial samples of both lichens from intensely polluted localities contained crystal blocks of high Ca concentration, which are most likely calcium-oxalate (CaC2O4) forms. It was concluded that high amounts of Ca and Mg in lichen samples were associated with air pollution and may be demonstration of environmental stress in Isparta.
... Functional categorisation can be a powerful tool in understanding responses to environmental factors. The use of functional traits, such as reproductive strategy, growth form and eutrophication tolerance, is a rapidly growing field of research in lichen ecology [25,26,56]. Individual lichen species can show strong preferences for bark chemistry and are often functionally categorised according to their substrate pH preference [31,57,58] and nitrogen tolerance [59,60]. ...
... For functional trait analysis, we assigned functional groups to each species for two traits, reproductive strategy (sexual vs. asexual-sorediate) and substrate pH preference (acidophilous vs. basidophilous). These were assigned according to [56,60] (see Table S1 for functional groups information). Non-binary functional traits were not included to simplify analyses. ...
Urban areas may contain a wide range of potential habitats and environmental gradients and, given the many benefits to human health and well-being, there is a growing interest in maximizing their biodiversity potential. However, the ecological patterns and processes in urban areas are poorly understood. Using a widely applicable ecological survey method, we sampled epiphytic lichen communities, important bioindicators of atmospheric pollution, on host Quercus trees in urban parks of London, UK, to test if common patterns relating to lichen diversity are mirrored in urban green spaces. We found lichen diversity to be dependent on host species identity, and negatively related to local tree crowding. In addition, we found a strong negative effect of tree size on lichen diversity, leaving large trees as unexploited niches. A novel network analysis revealed the presence of only pioneer communities, showing the lichen communities are being held in successional stasis, likely due to the heritage effects of SO2 emissions and current nitrogen pollution and particulate emissions. Our study highlights that jointly assessing species richness, community structure and the successional stage can be key to understanding diversity patterns in urban ecosystems. Subsequently, this may help best determine the optimum conditions that will facilitate biodiversity increase within cities.
... According to our data, macrolichens form a more threatened segment of lichenized taxa compared to microlichens (Figs 1 & 4). This result is consistent with earlier studies indicating that macrolichen species are less tolerant to air pollution and disturbances than microlichens Guttová et al. 2017;Degtjarenko et al. 2018) and are vulnerable to climate change, either because they are more sensitive to decreasing water supply (Boch et al. 2019) or due to their higher dispersal limitations (Dettki et al. 2000). Macrolichen richness has been shown to be positively related to the total richness of microlichens; however, the number of threatened macrolichens was not an important predictor for threatened microlichens (Bergamini et al. 2007). ...
National Red Lists are useful tools in establishing local conservation priorities. The threat status of Estonian lichens based on the IUCN system has been assessed twice, in 2008 and 2023. In the latest Red List, the proportion of species of elevated conservation concern, that is taxa belonging to the Near Threatened and threatened categories or having become regionally extinct in Estonia, was high (58%) while Least Concern (LC) species represented one-third (36%) of all taxa. Macrolichens were more threatened than microlichens. The Red List Index (RLI), illustrating the trends of species in their projected extinction risk, was calculated. The values were low (< 0.7 in 2023), thus indicating a heightened risk both for the set of all species and for macrolichens. More than half of all Estonian lichens are associated with woodlands and 54% of these species are of elevated conservation concern. Lichens preferring broad-leaved deciduous trees included more threatened than LC species, while among lichens preferring other deciduous or coniferous trees the proportion of LC species was higher than that of threatened taxa. Lichens inhabiting calcareous grasslands had the highest share (69%) of taxa of elevated conservation concern. Comparisons of national red-listed data with four selected countries (Czech Republic, Denmark, Finland and Sweden) revealed that the biggest overlaps of Estonian taxa of elevated conservation concern were with the Czech Republic and Finland.
... Следует отметить, что воздействие пылевого загрязнения на лишайники менее изучено [Zvereva et al., 2008;Paoli et al., 2014;Rai, 2016;Degtjarenko et al., 2018] по сравнению с влиянием кислотообразующих газообразных эмиссий (SO 2 , NOx, NH 3 и др.), наиболее губительных для эпифитных лишайников [Hawksworth, Rose, 1970;Skye, 1979;Инсарова, 1982;Нильсон, Мартин, 1982;Santamaría, Martín, 1997;van Herk, 2001;Sujetoviene, 2015;и др.]. ...
Представлены результаты многолетнего мониторинга (2002-2017 гг.) состояния эпифитного лишайника Hypogymnia physodes на территории воздействия Средне-Тиманского бокситового рудника (Республика Коми), где основным загрязнителем окружающей среды является пыль с преобладанием в ее составе Al и Fe. Выделены три периода реакции лишайника на загрязнение: шоковый, максимальных изменений, адаптации. В результате загрязнения значительно снизилось проективное покрытие вида, увеличилась доля некрозов талломов, уменьшились их линейные размеры. Через десять лет после начала мониторинга показатели жизненного состояния H. physodes стали стабилизироваться, а затем и улучшаться, что можно объяснить адаптацией лишайника к хроническому загрязнению среды пылевыми выпадениями. Изучение динамики содержания основных поллютантов показало, что в процессе эксплуатации рудника происходит их накопление в талломах лишайника в ряду: Al > Fe> Ni > Cu > Pb.
Here, we present the results of long-term monitoring (2002-2017) of epiphytic lichen Hypogymnia physodes in the influence zone of the Middle Timan Bauxite Mine (Komi Republic). The main environmental pollutant in this area is dust with a predominance of Al and Fe. Three periods of the reaction of lichen to dust pollution are identified: shock, maximum changes, and adaptation. Dust pollution significantly decreased the projective cover of the species under study, increased the frequency of thallus necrosis and decreased thallus linear dimensions. In ten years after we started our monitoring studies, the vital state parameters of H. physodes began to stabilize and then to improve due to adaptation of the lichen to chronic environmental pollution with dust. The study of changes in the content of main pollutants showed that, during the mine operation, they accumulate in the thalli of the lichen H. physodes in the following order: Al > Fe > Ni > Cu > Pb.
... Research on the effects of particulate matter on lichens has mainly focused on the specificity of pollut-ant accumulation [6] and changes in species abundance and diversity [7]. ...
... A large number of works are devoted to the study of the accumulation of heavy metals in lichens in the area of activity of metallurgical enterprises [4][5][6], their localization [3,7], absorption mechanisms [8,9] and detoxification [10]. In several studies [11,12] It was shown that long-term pollution of territories by dust emissions during the development of ore deposits leads to changes in the number and structure of lichen communities and the morphology of their thalli. Dust emissions are a complex heterogeneous mixture of airborne, often insoluble, solid particles that vary in size, origin, and chemical composition [13]. ...
... Los líquenes son ampliamente utilizados como bioindicadores de contaminación ambiental (Conti y Cecchetti 2001). Es reconocido el uso de las características de las comunidades liquénicas (El Mokni et al. 2015, Lopes et al. 2019) o sus rasgos funcionales (Degtjarenko et al. 2018, Koch et al. 2019) como indicadores del grado de contaminación o perturbación ambiental. Los MP como contaminantes emergentes relacionados con los líquenes no han sido explorados a profundidad. ...
One of the most important problems related to plastic waste is the production of micro-plastics (MPs), whose accumulation in different taxa has been recorded. It was recently found through field sampling that lichens are able to accumulate MPs. The present work aims to experimentally study the accumulation and deposition of MPs in three lichen species of the genera Usnea, Ramalina and Punctelia. We measured the weight, water uptake and fractal dimension of each thallus. Under laboratory conditions, we exposed 12 thalli of each species to three different doses of MPs in aqueous suspension (3, 6, and ≤12 MP/mL) for one week. The accumulated and deposited MPs were extracted and counted. Accumulation was negligible. We modelled deposition with general linear models. The fractal dimension variable was the only one significantly related to deposited MPs. These results suggest that in communities with higher structural complexity, measured by fractal dimension, we will find higher levels of deposited MPs .
... It should be noted that the effect of dust pollution on lichens is less studied (Zvereva et al, 2008;Paoli et al., 2014;Rai, 2016;Degtjarenko et al., 2018) when compared with the effect of acid-forming gaseous emissions (SO 2 , NO x , NH 3 , etc.), the most harmful for epiphytic lichens (Hawksworth and Rose, 1970;Skye, 1979;Nielson and Martin, 1982;Insarova, 1982;Santamaria and Martín, 1997;van Herk, 2001;Sujetoviene, 2015;etc.). ...
Here we present the results of long-term monitoring (2002–2017) of epiphytic lichen Hypogymniaphysodes in the zone of influence of the Middle Timan bauxite mine (MTBM) (Komi Republic). Dust witha predominance of Al and Fe is the main environmental pollutant in this area. Three periods of the responseof lichen to dust pollution are identified: shock, maximum changes, and adaptation. The dust pollution sig-nificantly reduced the projective cover of the species under study, increased the frequency of thallus necrosis,and decreased thallus linear dimensions. In the 10 years after we started our monitoring studies, the parame-ters of the vital state of H. physodes began to stabilize and then improve due to the adaptation of the lichen tochronic environmental pollution with dust. The study of changes in the content of main pollutants showedthat, during the mining operation, they accumulate in the thalli of the lichen H. physodes in the followingorder: Al > Fe > Ni > Cu > Pb.
(PDF) Reaction of the Lichen Hypogymnia physodes to Dust Pollution in the Influence Zone of the Middle Timan Bauxite Mine. Available from: https://www.researchgate.net/publication/371678231_Reaction_of_the_Lichen_Hypogymnia_physodes_to_Dust_Pollution_in_the_Influence_Zone_of_the_Middle_Timan_Bauxite_Mine [accessed Oct 05 2023].
... Indirect effect is exerted through the alteration of chemical properties of their substrates. Alkaline dust changes oligotrophic bark (nutrient-poor bark) to eutrophic bark (nutrient-rich bark), which promotes a nitrophilous or basiphilous community but reduces an acidophilous community (Degtjarenko et al., 2016(Degtjarenko et al., , 2018Gilbert, 1976;Paoli et al., 2014). In highly polluted areas, dust directly affects all lichen communities and creates lichen deserts (zones without lichens) (Paoli et al., 2014). ...
Cement production, quarrying and stone crushing are major emission sources of alkaline dust that can affect human health and vegetation. The main objectives of this study were to evaluate the potential of using bark pH, soil pH and lichen community for indicating alkaline dust pollution. Twelve polluted sites were in a limestone industrial area. Bark pH and the lichen community were observed on Alstonia scholaris trees, and soil pH was obtained from topsoil samples. The bark pH at all polluted sites was significantly higher (5.5 to 7.3) than that at the unpolluted site (4.3). Among the polluted sites, the highest bark pH value was observed at the nearest site to the center of the industrial area, while the lowest value was discovered at the farthest site. Bark pH showed a strongly negative correlation with the distance from the center. Soil pH at the unpolluted site (6.3) was also significantly lower than that at the polluted sites (7.6 to 8.1), except at the farthest site (6.5). The soil pH also tended to increase closer to the center. Seven lichen species were observed on the trunks of investigated trees in all polluted sites and were observed only at sites more than 4.7 km away from the center, where bark pH ranged from 5.5 to 6.3. The extent of dust impact on vegetation seemed to be within 6–7 km from the center. The results of this study confirm the potential of the bark pH of A. scholaris, soil pH and lichen community as long-term indicators of alkaline dust pollution.
... Investigations concerning the indicator nature of lichens were extended to the monitoring of land use intensity, and they were studied in a wider context [26][27][28][29], with due attention also given to the effect of the substrate [30][31][32][33][34]. For monitoring studies, the time passed has a key importance [35]. ...
Simple Summary
As the occurrences of lichens are strongly correlated to background environmental conditions (e.g., air pollution, global warming), the analysis of their distribution has a great value for bioindication. Distribution data are originating from earlier herbarium collections, recent field and literature studies. The distribution analyses in lichen species with different ecological requirements allowed comparisons and showed clear trends. Five distribution types were introduced—presented by characteristic examples—according to lichen distribution maps prepared in different periods of time (representing changing environmental conditions): (1) species of decreasing occurrences by time (acidic pollution sensitive species), (2) species with no or few former records but with increasing occurrences in recent decades (sub-Mediterranean species), (3) species with increasing and then (from c. 2000) decreasing occurrences (acidofrequent species), (4) species with widely increasing occurrences in recent decades (nitrofrequent species), and (5) species with rapidly increasing occurrences (rapidly spreading species of uncertain reasons). The discussed trends are known for some species at a global scale or European level, other examples are characteristic for Central Europe or Hungary. By studying the distribution maps of lichen bioindicators, tendencies of climate change and type of pollution can be determined and further changes can be predicted.
Abstract
Distribution data originating from earlier herbarium collections and recent biodiversity records form the basis of distribution analyses in lichen species with different ecological requirements, where the records allowed comparisons or showed clear trends. As the occurrences of lichens are strongly correlated to background environmental conditions (e.g., air pollution, global warming), confirmed by Wirth’s ecological indicator values, the analysis of distribution types has a great value for bioindication and the establishment of current and future climatic and pollution situations. Five distribution types were introduced—presented by characteristic examples (13)—according to lichen distribution maps prepared in different periods of time (representing changing environmental conditions): (1) species of decreasing occurrences by time (e.g., Lobaria pulmonaria, Menegazzia terebrata, suboceanic, acidic pollution sensitive species), (2) species with no or few former records but with increasing occurrences in recent decades (e.g., Flavoparmelia soredians, Hyperphyscia adglutinata, Solenopsora candicans, sub-Mediterranean species), (3) species with increasing and then (from c. 2000) decreasing occurrences (e.g., Scoliciosporum chlorococcum, Straminella conizaeoides, acidofrequent species), (4) species with widely increasing occurrences in recent decades (e.g., Physcia aipolioides, Piccolia ochrophora, Xanthoria parietina, nitrofrequent species), and (5) species with rapidly increasing occurrences (e.g., Absconditella lignicola, Coenogonium pineti, Evernia divaricata, rapidly spreading species). The proposed distribution types of lichen species may be applied to wider regions (the European or the global level).
... Similarly, more fissured bark appears to be less adequate for the establishment and propagation of lichen morphotypes. Degtjarenko et al. [95] showed that foliose lichen, in particular, prefer more acidic substrates, and a number of other studies have shown a correlation between CBH and BF and the composition of the lichen found on the trunks [47,96,97]. However, Spier et al. [98] elucidated that, when analyzed alone, bark characteristics may not present a significant effect on the composition of the lichen found on the trunk, and that the tree species may be a more important factor. ...
Habitat fragmentation affects lichen communities by inducing edge effects, although the dispersal of pollutants by pesticide drift from commercial crops may also provoke alterations in community structure, due to the varying sensitivity of lichen morphotypes to pollutants. In this context, we tested the hypothesis that lichen morphotype richness and diversity, and the percentage area of the trunks covered by different lichen morphotypes are modified significantly at the edges of fragments of Cerrado vegetation inserted within the agricultural matrix. We evaluated habitat fragments representing different Cerrado formations (Cerradão, Cerrado sensu stricto, and seasonal semi-deciduous forest) as well as the Emas National Park, a prominent Cerrado conservation unit. We used Generalized Linear Mixed Models (GLMMs) to test the potential of the models compiled using a mixture of phytosociological and environmental parameters, including the species, the height of the host plant (H), the circumference of its stem at breast height (CBH), total chlorophyll (TC), bark fissuring (BF) and pH, and illuminance (Lum), to explain the observed variation in the lichen morphotype richness and the percentage cover of the trunks by corticolous lichen morphotypes at the center and edge of the fragments. The central areas invariably had a greater diversity of morphotypes in all the fragments. The morphotypes considered highly sensitive to disturbance were not observed in edge areas, confirming a clear edge effect, as well as the influence of pesticide drift from the adjacent farmland matrix, on the structure of the lichen community. At both the edge and center sites, the larger trees (higher CBH) with less fissured bark tended to have the greatest diversity of lichen morphotypes, and more acidic barks had the greatest lichen cover. The models tested indicated that the variable tree species is an important determinant of the observed patterns of lichen morphotype richness and cover, either on its own or in association with pH or CBH + pH. The analyses also indicated that all the variables tested are important in some way for the definition of the percentage cover of the host trunks. The present study contributes to the understanding of the diversity of the corticolous lichen communities in the remaining fragments of Cerrado vegetation and the effects of the agricultural matrix on this community. The lichen may thus play a role as indicators of impact on other species, these organisms may provide important insights for the further investigation of the disturbance caused by the agricultural matrix on the communities of other groups of organisms.
... Many studies on air quality are based on testing of lichens, in which a large number of papers have described the air quality level in urban areas (Blasco, Domeño, & Nerín, 2008;Calvelo, Baccalá, & Liberatore, 2009;Gerdol, Marchesini, Lacumin, & Brancaleoni, 2014;Käffer et al., 2011;Kirschbaum, Cezanne, Eichler, Hanewald, & Windisch, 2012;Lisowska, 2011;Stamenković, Ristić, Đekić, Mitrović, & Baošić, 2013). Degtjarenko, Matos, Marmor, Branquinho, and Randlane (2018) suggested that lichen growth form, reproductive strategy, and tolerance to substrate pH could serve as potential tools for indicating the effects of dust pollution. The study conducted by Szwed, Kozłowski, and Żukowski (2020) showed a high level of lichen sensitivity to air quality changes created by anthropogenic impact. ...
This paper deals with using lichens as a bioindicators of the air quality and it was conducted on the territory of balneological center Prolom Banja (Southern Serbia). The exploration was conducted in the year 2019. The analysis of the sample from 15 investigated points indicates the presence of 72 lichen taxa, which shows that this area is rich in lichen species. For each investigated point, the index values of atmospheric purity (IAP) and index of human impact (IHI) were calculated. The IAP values varied in range from 40 to 56, while IHI values ranged between 8 and 24. Therefore, the map showing the air quality of the investigated area was made. There is a presence of “normal lichen zone” on the map which indicates that the air quality in this area is quite good. There are no significant air pollution sources in this area, so the level of pollution is considered low or very low. In the investigated area there are not stations for the monitoring of physico-chemical parameters of air quality. The investigation of air quality on the territory of Prolom Banja has not been done until now.
... In anthropogenic habitats, some endangered lichen species can colonize alternative trees species (Moe and Botnen 1997;Thor et al. 2010;Leppik et al. 2011;Kubiak and Osyczka 2019), probably due to substrate-altering 1 3 exogenous factors (e.g. dust pollution: Marmor et al. 2010;Suija and Liira 2017;Degtjarenko et al. 2018). Phorophyte plasticity and the substrate niche of epiphytic lichen species however are still poorly quantified (Arup et al. 2003;Schei et al. 2012;Bäcklund et al. 2016), as such analyses require a balanced sampling scheme covering the whole range of tree species in all wooded habitat types. ...
We hypothesize that many epiphytic lichens colonize trees in planted cultural heritage sites and persist as large-scale species meta-pools in historic rural landscape, while epiphytic biodiversity is threatened by the timber oriented forest management. We performed a stratified survey of epiphytic lichen species pools on ten common tree species in three contrasting habitat types across 19 Estonian landscapes. The meta-pools were examined at local and regional scales. The response differences between two ecological subsets—common forest-dwellers and conservation indicators—were assessed. Tree species in parks and corridors hosted more lichen species than they did in production forests. For common forest-dwelling lichens the local species pool size was similar in all habitat types, while their regional pool was larger in forests and parks. On the contrary, for conservation indicator lichens the local pool size was the largest in corridors and regional pool size was the same in all habitats. Habitat type and tree species equally shaped the composition of the regional pool. Lichens were the most host-tree-specific in forests and had the widest host-tree niche in corridors. Broad-leaved tree species supported the largest regional species pools only in forest, while Betula and Pinus with Larix did in corridors. Lichen pools on Populus tremula were consistently the smallest. As the habitat quality of contemporary forests is too low for epiphytic lichens, cultural heritage sites should be considered as refugia in biodiversity conservation networks. Forestry and rural greening should emphasise stand diversification, ensuring the continuity of micro-habitats. Indicator lichen classifications require forest-oriented refinements.
... highly disturbed habitats. This trait was explored in a few other studies in Europe [37,38], one of them conducted in an urban environment [23]. The major potential of this trait is that it does not focus solely on the effects of pollutants in lichens communities, but rather it looks at all anthropic disturbances in an integrated way and also how those disturbances, their type, and intensity have changed over the years. ...
Urban environments are densely populated areas buzzing with a wide range of anthropic activities that cause disturbances like air pollution or the heat island effect, threatening both human and environmental health. Mitigating its impacts implies understanding the integrated effects that those disturbances exert on urban environments. Lichen biodiversity is frequently used as an ecological indicator, being able to integrate its effects in a quantifiable way. The poleotolerance response trait classifies lichens according to their tolerance to human disturbance, but it was developed for Italy’s flora and has seldom been applied outside Italy or in urban context studies. The aim of this work was to assess this trait suitability as an indicator of urban anthropic disturbance and test it outside Italy. For that, we sampled lichen diversity in 41 green spaces in Lisbon. Lichens were classified into the respective poleotolerance trait functional groups and their community weighted mean related with three type of environmental variables used as surrogates of urban disturbance. We showed that disturbance-tolerant functional groups could be used as an ecological indicator of the integrated effects of environmental disturbances. Some species were clearly misclassified, so we propose reclassification for those. Natural and seminatural functional groups did not behave as expected. Nevertheless, disturbance-tolerant functional groups have the potential to be used in in other Southern European cities.
... This is especially important in the light of ongoing climatic changes, but also for biodiversity and its protection. Moreover, a better understanding of the ecological mechanisms driving species assemblages in forests may be gained if lichen life history traits are also considered (Ellis and Coppins 2006, Giordani et al. 2012, Bässler et al. 2016, Randlane et al. 2017, Degtjarenko et al. 2018. For example, lichens with Trentepohlia as their photosynthetic partner thrive at higher temperatures and, as a result of climate warming, presently expand their distribution in Europe (Aptroot and van Herk 2007). ...
Deciduous forests with temperate broad‐leaved tree species are particularily important in terms of biodiversity and its protection, but are threatened habitats in northern Europe. Using multivariate analyses we studied the effect of forest site type, environmental variables and host tree properties on epiphytic lichen synusiae as well as on the composition of species‐specific functional traits. Epiphytic lichens were examined on Acer platanoides, Fraxinus excelsior, Quercus robur, Tilia cordata, Ulmus glabra and U. laevis in two types of forests: Humulus‐type floodplain forests and Lunaria‐type boreo‐nemoral forests on the talus slopes of limestone escarpment (klint forests). Klint forests located near the seashore were under greater maritime influence compared to floodplain forests located in inland Estonia which experience stronger air temperature contrasts. In addition to stand level and climatic variables, tree level factors (bark pH, trunk circumference and cover of bryophytes) considerably affected the species composition of the lichen synusiae. Overall, 137 lichen species were recorded, including 14 red‐listed species characteristic of deciduous trees. We defined 13 lichen societies and showed their preference to forests of a specific site type and/or host tree properties. In forests of both types, most of the epiphytic lichens were crustose, and had apothecia as the fruit bodies and chlorococcoid algae as the photobiont. However, the proportion of lichens with a foliose or fruticose growth form, as well as the proportion of lichens with vegatative diaspores, were higher in floodplain forests. In klint forests with a stronger influence from the wind, crustose species completely dominated, while species with vegetative diaspores were rare and most species dispersed sexually. Lichens with Trentepohlia as the photobiont were characteristic of these forests, and lichens with lirellate ascomata were prevailing, indicating the great uniqueness of the kint forests for epiphytic lichens in the boreo‐nemoral region.
... This is especially important in the light of ongoing climatic changes, but also for biodiversity and its protection. Moreover, a better understanding of the ecological mechanisms driving species assemblages in forests may be gained if lichen life history traits are also considered (Ellis and Coppins 2006, Giordani et al. 2012, Bässler et al. 2016, Randlane et al. 2017, Degtjarenko et al. 2018. For example, lichens with Trentepohlia as their photosynthetic partner thrive at higher temperatures and, as a result of climate warming, presently expand their distribution in Europe (Aptroot and van Herk 2007). ...
The research was carried out between 2021 and 2023 in zones A‒D, 400, 600, 1000, and 1500 m away from the magnesite plant in Lubeník (central Slovakia), which are polluted by magnesite immissions. Due to the fall of magnesite dust, the Organic horizons became neutral to weakly acidic, the mineral layers of soils in zones A and B strongly to weakly alkaline, and neutral in zones C and D. Ca, Mg, and Na in the Organic horizon and 0–5 cm soil layers decreased from zone A toward zone D. Mn and K increased from zone A to zone D. Cd generally increased from zone A to zone C. A total of 107 species of macromycetes from the phyla Ascomycota (15) and Basidiomycota (92) were detected. The absolute best accumulator of Ca and Mg was Hymenochaete rubiginosa and Ca, Mg, and Mn Geastrum rufescens. The best K accumulator was Inosperma erubescens together with Russula cyanoxantha, and the absolute best Na accumulator was Clitocybe phyllophila. Cd was best accumulated by Hymenochaete rubiginosa and Inosperma erubescens. PCA showed that soil properties depended on pH values and C, N, K, and Na content. The mentioned variables were significantly correlated with PC1 (share 46%), while the contents of Ca, Mg, Mn, and Cd were correlated with PC2 (share 35%). Ca and Cd were the most important environmental variables accumulated in macromycete fruiting bodies. PC1 represents a significant axis for the prediction of Ca content (40.2%) and PC2 for the prediction of Cd content in macromycetes (19%). Environmental pollution by Mg emissions significantly contributed to soil degradation and the composition of macromycete communities. The knowledge gained can help in the implementation of corrective measures in areas affected by alkaline immissions.
We studied the accumulation and localization of metals in the foliose lichens Lobaria pulmonaria, Hypogymnia physodes and Peltigera aphthosa, living in the impact zone of the Sredne-Timansky bauxite mine. A significant accumulation of Al (16–19 g/kg), Fe (16–20 g/kg) and Ti (0.3–0.7 g/kg) by thalli was revealed. From 29 to 82% of the total content of these metals is localized in dust particles weakly attached to the surface of the thalli. The total proportion of intra- and extracellularly bound Al, Fe and Ti did not exceed 11%. 15–56% of these metals were found in the residual fraction. An increase in the content of Cu, Pb, Co and Ni was detected in thalli collected in the impact area. It has been shown that the localization of metals in thalli depends both on the element under consideration and on the morphological and anatomical characteristics of the thalli: in L. pulmonaria, fine mineral particles were localized on the surface of the thalli; in the thalli of P. aphthosa, which do not have a lower cortex, mineral inclusions were found throughout the entire thickness of the thalli.
The Royal Netherlands Meteorological Institute (KNMI) has published the KNMI’06 climate scenarios in 2006. These scenarios give the possible states of the climate in The Netherlands for the next century. Projections of changes in precipitation were made for a time scale of 1 day. The urban drainage sector is, however, more interested in projections on shorter time scales. Specifically, time scales of 1 h or less. The aim of this research is to provide projections of precipitation at these shorter time scales based on the available daily scenarios. This involves an analysis of climate variables and their relations to precipitation at different time scales. On the basis of this analysis, one can determine a numeric factor to translate daily projections into shorter time scale projections.
The importance of single-species forest plantations in sustaining biodiversity could be bigger than expected. We described the diversity of lichens and bryophytes in 15 midterm (16- to 17-year-old) hybrid aspen (Populus tremula × Populus tremuloides) plantations in Estonia. Species richness and composition data were linked with environmental and landscape-scale variables. Altogether, 44 lichen and 37 bryophyte species were recorded from plantations; richnesses of bryophytes and lichens were positively correlated. Lichen species composition was significantly affected by landscape-scale parameters (distance to the nearest present forest, distance to the nearest forest continuously occurring in the same place since the 1930s, and forest area in the study plot vicinity in the 1930s). Bryophyte species composition was affected mainly by light conditions and forest area in the 1930s. Among lichens, the sexual crustose species functional group dominated in midterm plantations; appearance of asexual lichens of different growth forms is expected during the next years. Our results indicate the importance of long-term availability of good-quality forests as sources of propagules. Short-rotation hybrid aspen plantations can provide temporary habitats for forest species and thus in part contribute to preserving landscape-scale biodiversity, if they are close to possible colonization sources. Green-tree retention in plantations will probably raise the biodiversity value of those short-term communities.
Nitrogen (N) has emerged in recent years as a key factor associated with global changes, with impacts on biodiversity, ecosystems functioning and human health. In order to ameliorate the effects of excessive N, safety thresholds such as critical loads (deposition fluxes) and levels (concentrations) can be established. Few studies have assessed these thresholds for semi-natural Mediterranean ecosystems. Our objective was therefore to determine the critical loads of N deposition and long-term critical levels of atmospheric ammonia for semi-natural Mediterranean evergreen woodlands. We have considered changes in epiphytic lichen communities, one of the most sensitive comunity indicators of excessive N in the atmosphere. Based on a classification of lichen species according to their tolerance to N we grouped species into response functional groups, which we used as a tool to determine the critical loads and levels. This was done for a Mediterranean climate in evergreen cork-oak woodlands, based on the relation between lichen functional diversity and modelled N deposition for critical loads and measured annual atmospheric ammonia concentrations for critical levels, evaluated downwind from a reduced N source (a cattle barn). Modelling the highly significant relationship between lichen functional groups and annual atmospheric ammonia concentration showed the critical level to be below 1.9 μg m−3, in agreement with recent studies for other ecosystems. Modelling the highly significant relationship between lichen functional groups and N deposition showed that the critical load was lower than 26 kg (N) ha−1 yr−1, which is within the upper range established for other semi-natural ecosystems. Taking into account the high sensitivity of lichen communities to excessive N, these values should aid development of policies to protect Mediterranean woodlands from the initial effects of excessive N.
Dust pollution can cause a significant damage of environment and endanger human health. Our study aimed to investigate epiphytic lichens and bryophytes in relation to long-term alkaline dust pollution and provide new insights into the bioindicators of dust pollution. We measured the bark pH of Scots pines and the species richness and cover of two cryptogam groups in 32 sample plots in the vicinity of limestone quarries (up to ca. 3 km) in northern Estonia. The bark pH decreased gradually with increasing distance from quarries. We recorded the changes in natural epiphytic communities, resulting in diversified artificial communities on pines near the pollution source; the distance over 2 km from the quarries was sufficient to re-establish the normal acidity of the bark and natural communities of both lichens and bryophytes. The cover of lichens and the number of bryophytes are a more promising indicator of environmental conditions than individual species occurrence. We confirmed previously proposed and suggested new bioindicator species of dust pollution (e.g., Lecidella elaeochroma, Opegrapha varia, Schistidium apocarpum). Limestone quarrying activity revealed a “parapositive” impact on cryptogamic communities, meaning that quarrying might, besides disturbances of natural communities, temporarily contribute to the distribution of locally rare species.
The relationships between traffic-related air pollution, bark pH and epiphytic lichen mycota on Pinus sylvestris and Tilia cordata were studied. Traffic is considered the main source of air pollution in Tallinn and, therefore, greatly influ- ences lichen composition and species richness, their diversity increasing on Pinus sylvestris near roadways but decreasing on Tilia cordata. Traffic also affected bark pH of Pinus sylvestris, but not of Tilia cordata: the bark of Pinus sylvestris is normally acid (mean pH in control plot 3.0) and is modified to subneutral (up to 5.7) near roadways. The influence of alkaline dust pollution, connected with traffic, is clearly observed on epiphytic lichen composition of P. sylvestris in Tallinn. Besides dust, nitrogen oxides are important pollutants too, but the effects of acidic air pollution are less evident now compared to the previous studies.
A unique, species-rich and endangered lichen biota can be found on European coastal and inland sand dunes. However, it is increasingly affected by natural succession as well as by anthropogenic disturbances. We studied lichen diversity on the grey dunes and dune heaths of coastal and inland regions of Estonia. A total of 28 study plots were investigated; in each 0.1 ha study plot general environmental variables and anthropogenic disturbances were described and all epigeic lichen species were identified. We found 66 lichenized fungus (lichen) species, including several rare and ten red-listed lichens. Multivariate analysis (DCA, CCA) was performed to examine gradients in species composition and to relate variation in species data to environmental factors. In addition, we used redundancy analysis (RDA) to relate variation in species’ trait composition to environmental factors. Species composition on grey dunes differed significantly from that on dune heaths. The characteristic species for grey dunes are, besides several Cladonia species, foliose lichens, e.g. Hypogymnia physodes, Parmelia sulcata and Peltigera spp. Also species’ traits composition was different for either habitat, indicating that sorediate lichens, foliose lichens, lichens with cyanobacterium as the main photobiont, and sparsely branched Cladonia species dominate on grey dunes, while esorediate, green-algal, crustose and richly branched fruticose lichens are common on dune heaths. Soil pH was the most essential environmental variable for determining both species composition and species’ traits composition. The composition of lichen species was also significantly influenced by forest closeness, soil Mg content and cover of bare sand; the effect of ground disturbances was low compared to the effect of these environmental factors. To protect and conserve the species-rich lichen biota, it is necessary to protect the dune habitats from building activity, to avoid overtrampling in recreation areas and to regularly remove shrubs and trees.
Unlabelled:
Multiple linkages connect air quality and climate change. Many air pollutant sources also emit carbon dioxide (CO2), the dominant anthropogenic greenhouse gas (GHG). The two main contributors to non-attainment of U.S. ambient air quality standards, ozone (O3) and particulate matter (PM), interact with radiation, forcing climate change. PM warms by absorbing sunlight (e.g., black carbon) or cools by scattering sunlight (e.g., sulfates) and interacts with clouds; these radiative and microphysical interactions can induce changes in precipitation and regional circulation patterns. Climate change is expected to degrade air quality in many polluted regions by changing air pollution meteorology (ventilation and dilution), precipitation and other removal processes, and by triggering some amplifying responses in atmospheric chemistry and in anthropogenic and natural sources. Together, these processes shape distributions and extreme episodes of O3 and PM. Global modeling indicates that as air pollution programs reduce SO2 to meet health and other air quality goals, near-term warming accelerates due to "unmasking" of warming induced by rising CO2. Air pollutant controls on CH4, a potent GHG and precursor to global O3 levels, and on sources with high black carbon (BC) to organic carbon (OC) ratios could offset near-term warming induced by SO2 emission reductions, while reducing global background O3 and regionally high levels of PM. Lowering peak warming requires decreasing atmospheric CO2, which for some source categories would also reduce co-emitted air pollutants or their precursors. Model projections for alternative climate and air quality scenarios indicate a wide range for U.S. surface O3 and fine PM, although regional projections may be confounded by interannual to decadal natural climate variability. Continued implementation of U.S. NOx emission controls guards against rising pollution levels triggered either by climate change or by global emission growth. Improved accuracy and trends in emission inventories are critical for accountability analyses of historical and projected air pollution and climate mitigation policies.
Implications:
The expansion of U.S. air pollution policy to protect climate provides an opportunity for joint mitigation, with CH4 a prime target. BC reductions in developing nations would lower the global health burden, and for BC-rich sources (e.g., diesel) may lessen warming. Controls on these emissions could offset near-term warming induced by health-motivated reductions of sulfate (cooling). Wildfires, dust, and other natural PM and O3 sources may increase with climate warming, posing challenges to implementing and attaining air quality standards. Accountability analyses for recent and projected air pollution and climate control strategies should underpin estimated benefits and trade-offs of future policies.
The elementary structural units where changes of plant communities come about are synusiae and studies of successional processes induced by external factors should focus on that scale. Synusia is a structural part of a plant community inhabiting a special microhabitat, with a specific floristic composition and consisting of species that belong to the same stratum and that do not differ fundamentally in either periodicity or way of exploitation of their environment. We studied the responses of the moss synusiae to the cement kiln dust pollution in Myrtillus site type forests in the vicinity of the Kunda cement plant (North Estonia). The synusiae were clustered into eight societies. The species content of the bryophyte synusiae changed completely along the alkaline pollution gradient. Synusiae of Dicranum polysetum-Pleurozium schreberi, Aulacomnium palustre-Hylocomium splendens and Ptilium crista-castrensis-Hylocomium splendens societies, characteristic of unpolluted forests, were replaced gradually by the synusiae of Rhytidiadelphus squarrosus-Hylocomium splendens, Climacium dendroides-Hylocomium splendens and Rhodobryum roseum-Rhytidiadelphus triquetrus societies as pollution increased. Brachytheciurn rutabulum-Rhytidiadelphus triquetrus and Fissidens dubius-Rhytidiadelphus triquetrus societies were indicative of forests with heavy alkaline pollution. The composition of epiphytic bryophytes also changed almost completely along the pollution gradient; Fissidens adianthoides, Tortula ruralis and Barbula unguiculata were indicative of the heavily polluted zone. We conclude that alkaline pollution has a clearly detectable impact on the forests' bryophyte synusiae in terms of both species composition and typological structure.
Climate change is expected to cause several impacts at the global scale, and drylands will be amongst the most affected areas. Thus, investigating how these changes will affect the composition, structure and functioning of dryland ecosystems has become a priority. From an ecological indicator point of view, several works have shown that functional diversity is better than species richness to understand ecosystem functioning or response to environmental factors. However, most of these works focus on plants, while those of other organisms remain largely unknown. Lichens are amongst the ecosystem components more sensitive to climatic changes due to several physiological and ecological characteristics. Their poikilohydric nature (therefore highly dependent on the atmosphere for water supply) and their ubiquity on terrestrial ecosystems underlie their potential as indicators of climate. Nonetheless, works specifically aiming to identify lichen functional traits that respond to aridity remain poorly explored, particularly in drylands.
We proposed to identify lichen functional traits and respective functional groups responding to aridity in a Mediterranean drylands ecosystem.
Lichen diversity was sampled in open holm oak woodlands along an aridity gradient in SW Europe (Iberian Peninsula). Lichen functional traits that could be easily identified and related to water uptake were selected to be tested: type of photobiont, growth form and reproduction strategy.
Lichen species composition was related to the aridity gradient. The three traits chosen were related with the community's response to aridity, but with contrasting responses in different functional groups. More specifically crustose and fruticose lichens, isidiate species and the ones with Trentepohlia as photobiont were related to the less arid part of the gradient. Foliose species and cyanolichens, on the contrary, were associated with the most arid areas.
Synthesis. We were able to identify lichen traits responding to aridity. Type of photobiont was particularly responsive, with Trentepohlia and cyanobacteria functional groups, responding clearly in contrasting ways to aridity in this drylands ecosystem. This work emphasizes functional diversity role on understanding and assessing the response to environmental factors, namely to climate. It also highlights the potential use of lichen functional groups as ecological indicators of climate change.
The autecology of rare species can be derived using similarities among functional traits and environmental conditions observed for common species, i.e. we employed the ‘matching analogy approach’ with the analytical scheme ‘common species → driver → trait → driver → rare species’. We addressed the driver–trait relationship for common epigeic lichens of thin-soil calcareous grasslands, which are endangered by cessation of traditional land use. Common lichens were suppressed by encroaching herbs and shrubs, and were supported by ground disturbances. The lichens of open low-productivity alvars are predominantly calciphilous, epibryic, crustose-squamulose, sexually reproducing and contain UV-protective pigments. Lichens of encroached alvars are soil-type generalists, fruticose, reproduce vegetatively and contain herbivore-deterring compounds. Rare lichens resemble the species of open low-productivity alvars, except their more limited niche space, i.e. they are restricted to arctic-alpine habitats. The conservation practices on alvars should support the formation of crust-forming communities by suppressing the growth of shrubs and herbs, and by promoting recurrent small-scale soil disturbances.
Predicting ecosystem responses to global change is a major challenge in ecology. A critical step in that challenge is to understand how changing environmental conditions influence processes across levels of ecological organization. While direct scaling from individual to ecosystem dynamics can lead to robust and mechanistic predictions, new approaches are needed to appropriately translate questions through the community level. Species invasion, loss, and turnover all necessitate this scaling through community processes, but predicting how such changes may influence ecosystem function is notoriously difficult. We suggest that community-level dynamics can be incorporated into scaling predictions using a trait-based response–effect framework that differentiates the community response to environmental change (predicted by response traits) and the effect of that change on ecosystem processes (predicted by effect traits). We develop a response-and-effect functional framework, concentrating on how the relationships among species' response, effect, and abundance can lead to general predictions concerning the magnitude and direction of the influence of environmental change on function. We then detail several key research directions needed to better scale the effects of environmental change through the community level. These include (1) effect and response trait characterization, (2) linkages between response-and-effect traits, (3) the importance of species interactions on trait expression, and (4) incorporation of feedbacks across multiple temporal scales. Increasing rates of extinction and invasion that are modifying communities worldwide make such a research agenda imperative.
The sulphur dioxide in the air can be estimated qualitatively by
studying the lichens growing on trees. A ten-point scale has been
constructed and used in pilot surveys in England and Wales, south-east
England and the city of Leicester.
Understanding the processes shaping biological communities under multiple disturbances is a core challenge in ecology and conservation science. Traditionally, ecologists have explored linkages between the severity and type of disturbance and the taxonomic structure of communities. Recent advances in the application of species traits, to assess the functional structure of communities, have provided an alternative approach that responds rapidly and consistently across taxa and ecosystems to multiple disturbances. Importantly, trait-based metrics may provide advanced warning of disturbance to ecosystems because they do not need species loss to be reactive. Here, we synthesize empirical evidence and present a theoretical framework, based on species positions in a functional space, as a tool to reveal the complex nature of change in disturbed ecosystems.
In the Netherlands a monitoring programme is in operation to map the effects of ammonia pollution with epiphytic lichens. The method is presented here and the results are statistically correlated with abiotic data. The abundance of nitrophytes on Quercus robur appears to be a useful parameter. Detailed spatial patterns of ammonia pollution can be obtained with lichens. To avoid interference, it is important to consider other influences, for example dust, climate, exposure, age of the trees and other pollutants.
The lichen composition on wayside Quercus robur in the Netherlands was related to bark properties (pH, EC, NH4+, SO42-, NO3-) and levels of air pollution (SO2 and NH3). The pH of the bark and the susceptibility to toxic substances appear to be the two major primary factors affecting epiphytic lichen composition. These factors have independent effects on the lichen composition. Most of the so-called nitrophytic species appear to have a low sensitivity to toxic effects of SO2; their only requirement being a high bark pH. An increased bark pH appears to be the primary cause of the enormous increase in nitrophytic species and the disappearance of acidophytic species over the last decade in the Netherlands. Measurements of ambient NH3 concentrations in the air show that there is a nearly linear relationship between the NH3 concentration and the abundance of nitrophytes on Quercus. The abundance of nitrophytes was not correlated with SO2 concentrations. Most of the acidophytic species appear very sensitive to NH3 since in areas with concentrations on 35 microgr. m-3 or more, all acidophytic species have disappeared. Current methods using species diversity to estimate or monitor SO2 air pollution need some modification, otherwise the air quality may be erroneously considered to be relatively good in areas with high NH3 levels.
We analysed a dataset composed by the frequency of 79 epiphytic lichens recorded on 243 oaks distributed in 29 oak dominated stands of the Western Carpathians, representing areas with high environmental quality up to disturbed environments. Lichen diversity indices (based on total frequencies and on functional and morphological groups) were used as indicators of the response to air quality and forest management. The level of air quality in these categories was a function of NOx, SO2 and particulate matter. From management viewpoint the units were classified as managed (areas subjected to periodic logging) and semi-natural (which currently have the status of National Nature Reserve and where eventual management practices date back to the history). The results showed that higher environmental levels of pollution were associated to the decrease of fruticose and in general pollution sensitive species, while low environmental levels of pollution were associated to the diffusion of common nitrophilous lichens as well as to a higher share of fruticose and in general pollution sensitive species. As far as forest management is concerned, a higher share of fruticose and sensitive species was associated to semi-natural and natural stands, whereas a higher share of foliose (pioneer and tolerant) species was associated to the managed stands.
The epiphytic lichens around limestone and sandstone quarries were investigated in northern Greece and central Italy to study the effect of alkaline and acid dust on epiphytic lichen vegetation in the Mediterranean area. The results showed that the main factor influencing the diversity of the epiphytic lichen vegetation studied is the distance from quarries, and that the chemistry of dust is not an important parameter. The fact that all but a few resistant lichen species die when subjected to high dust concentrations suggests that epiphytic lichens could be usefully employed for monitoring dust fallout and the effects of dust contamination.
• Lichens have been used to efficiently track major drivers of global change from the local to regional scale since the beginning of the industrial revolution (sulphur dioxide) to the present (nitrogen deposition and climate change). Currently, the challenge is to universalize monitoring methodologies to compare global change drivers’ simultaneous and independent effects on ecosystems and to assess the efficacy of mitigation measures.
• Because two protocols are now used at a continental scale North America (US) and Europe (EU), it is timely to investigate the compatibility of the interpretation of their outcomes. For the first time, we present an analytical framework to compare the interpretation of data sets coming from these methods utilizing broadly accepted biodiversity metrics, featuring a paired data set from the US Pacific Northwest.
• The methodologies yielded highly similar interpretation trends between response metrics: taxonomic diversity, functional diversity and community composition shifts in response to two major drivers of global change (nitrogen deposition and climate). A framework was designed to incorporate surrogates of species richness (the most commonly used empirical trend in taxonomic diversity), shifts in species composition (compositional turnover) and metrics of functional diversity (link between community shifts to effects and ecosystem structure and functioning). These metrics are essential to more thoroughly comprehend biodiversity response to global change. Its inclusion in this framework enables future cross-continental analysis of lichen biodiversity change from North America and Europe in response to global change. Future works should focus on developing independent metrics for response to global change drivers, namely climate and pollution, taking us one step closer to a lichen-based global ecological indicator.
Dust storms originate in many of the world’s drylands and frequently present hazards to human society, both within the drylands themselves but also outside drylands due to long-range transport of aeolian sediments. Major sources of desert dust include the Sahara, the Middle East, central and eastern Asia, and parts of Australia, but dust-raising occurs all across the global drylands and, on occasion, beyond. Dust storms occur throughout the year and they vary in frequency and intensity over a number of timescales. Long-range transport of desert dust typically takes place along seasonal transport paths. Desert dust hazards are here reviewed according to the three phases of the wind erosion system: where dust is entrained, during the transport phase, and on deposition. This paper presents a synthesis of these hazards. It draws on empirical examples in physical geography, medical geology and geomorphology to discuss case studies from all over the world and in various fields. These include accelerated soil erosion in agricultural zones – where dust storms represent a severe form of accelerated soil erosion – the health effects of air pollution caused by desert aerosols via their physical, chemical and biological properties, transport accidents caused by poor visibility during desert dust events, and impacts on electricity generation and distribution. Given the importance of desert dust as a hazard to human societies, it is surprising to note that there have been relatively few attempts to assess their impact in economic terms. Existing studies in this regard are also reviewed, but the wide range of impacts discussed in this paper indicates that desert dust storms deserve more attention in this respect.
Aims
We hypothesize that the community response to disturbances can be interpreted as a large‐scale dynamic equilibrium between multiple alternate states stemming from different species pools within a regional meta‐pool and being limited by species’ multi‐dimensional niches. We explore this hypothesis by examining the re‐assembly of an acidophilous lichen community in response to long‐term alkaline dust pollution, assuming understorey as a potential side‐factor.
Location
Around a cement factory in Kunda, Estonia.
Methods
Lichen communities on Scots pine (Pinus sylvestris) trunks in 40 stands around a cement factory and in nine distant limestone habitats were assessed.
Results
The formed bark pH gradient from pH 2.4 to 8.1 was reflected in a continuum of lichen communities on pines from acidophilous to basidophilous communities. Besides suppressing species richness, understorey density more evidently caused the compositional divergence from neutral bark conditions. The effect of hidden interactions among drivers was explained through reactions of individual species – almost all species across the pollution gradient were pH‐limited, whereas species adapted to neutral or alkaline substrate were additionally sensitive to understorey conditions. The hump‐shaped distribution of pH niche ranges along the observed niche optima, rather than ecological indicator values, showed that the shape of species’ multi‐dimensional niche‐space still needs to be quantified.
Conclusions
Each alternative community state along the disturbance gradient represents a realization of its specific species pool within the meta‐pool. Degradation can be defined if the community state is not supported by a meta‐pool. Species infiltration during community re‐assembly can be predicted using species source communities as cost‐efficient proxies.
We present new data and analyses revealing fundamental flaws in a critique of two recent meta-analyses of local-scale temporal biodiversity change. First, the conclusion that short-term time series lead to biased estimates of long-term change was based on two errors in the simulations used to support it. Second, the conclusion of negative relationships between temporal biodiversity change and study duration was entirely dependent on unrealistic model assumptions, the use of a subset of data, and inclusion of one outlier data point in one study. Third, the finding of a decline in local biodiversity, after eliminating post-disturbance studies, is not robust to alternative analyses on the original dataset, and is absent in a larger, updated dataset. Finally, the undebatable point - noted in both original papers - that studies in the ecological literature are geographically biased, was used to cast doubt on the conclusion that, outside of areas converted to croplands or asphalt, the distribution of biodiversity trends is centered approximately on zero. Future studies may modify conclusions, but at present, alternative conclusions based on the geographic-bias argument rely on speculation. In sum, the critique raises points of uncertainty typical of all ecological studies, but does not provide an evidence-based alternative interpretation. This article is protected by copyright. All rights reserved.
In the last decades, the pollution regime has been drastically changed in most industrialized countries, with a considerable decrease in sulphur dioxide (SO2) emissions and an increasing relevance of eutrophication compounds, such as nitrogen compounds and particulate matter. This situation hampers the interpretation of data in biomonitoring surveys, as high lichen diversity is not always associated with good air quality. The objective of this study was to test whether the effects of eutrophication on the abundance of different lichen functional groups varies according to some tree-related factors. We analysed the relationships between epiphytic lichen diversity, emissions of main atmospheric pollutants and tree characteristics (circumference and bark pH, light transmitted through the canopy). Hierarchical partitioning of variance and Generalized Linear Mixed Models (GLMM) confirmed that lichen functional groups with different nitrogen tolerances responded to several atmospheric pollutants, with both independent and joint effects, whereas they did not show significant differences depending on main tree-related factors. We demonstrated that, under high eutrophication levels, differences in bark pH did not significantly differentiated the composition of epiphytic lichen communities.
Very little is known whether and how air pollution impacts genetic diversity of lichenized fungi that are well-known indicators of environmental quality. We studied the genetic variation of eight Usnea subfloridana populations in Pinus sylvestris-dominated boreal forest stands in southern Estonia, Northern Europe; four of these populations were exposed to long-term dust pollution released from unpaved road. The mean bark pH of lichen-phorophyte differed considerably between polluted and unpolluted forest stands. We genotyped 274 Usnea thalli using nine specific fungal microsatellite markers. Genetic variation measures were calculated and compared between populations from different habitats. Allelic richness, Shannon's information index, and genetic diversity of lichen populations were significantly higher in unpolluted forest sites than in polluted forest sites. We conclude that environmental disturbances caused by alkaline dust pollution had negative impact on the genetic variation of U. subfloridana, a common species of lichenized fungi.
This chapter describes lichen deserts and their causes, effect of sulfur dioxide (SO2) on growth and metabolism, and several other environmental factors. The size and shape of lichen deserts—elongated downwind and often extending for many miles beyond the built-up area—clearly point to some airborne influence. The size and shape of an area affected by pollution can be discovered rapidly (and cheaply) by mapping indicator species. By using different species and varying the substratum, it is possible to determine a boundary at almost any distance from a conurbation. There are several effects of SO2 on growth and metabolism, which includes growth, physiological and biochemical, other pollutants, and their resistance to pollution. When SO2 levels are high, pollution does tend to be a master factor incapable of modification. Further, there is evidence that any map showing the distribution of lichens also contains information on regional levels of air pollution.
Biomonitoring which is more and more widely used and data from measurements enables comprehensive tracking of hazards and positive changes in areas under anthropopressure. Among many diverse bioindicators the lichens are commonly used. The lichens are used to detect heavy metals, radionuclides, air pollutants, polynuclear aromatic hydrocarbons (PAH) and polychlorinated biophenyls (PCB). Because of high air pollution in urban areas, occurrence of the lichens is very limited. These bioindicators can be used by transplantation method. The purpose of the study was to determine accumulation of heavy metals coming from cement dust and morphological changes of lichen thalli transplanted in Kielce. The lichens were transported on branches from Borecka Forest. The branches were hanged in three points of the city. After 3-month exposure, the lichens were prepared for chemical analysis to determine Cd, Pb, Fe and Zn which was conducted with IL 251 atomic absorption spectrophotometer (AAS). Metals were determined at the following wavelengths: cadmium - λ = 228.8 nm, lead - λ = 217 nm, copper - λ = 324.7 nm, iron - λ = 248.3 nm, zinc - λ = 213.9 nm. The highest average concentrations of Zn, Cd, Cu and Pb were observed during cold period of 2006 - I quarter (41.69 mg·kg -1 d.m.) and IV quarter (41.77 mg·kg -1 d.m.) whereas in warm period (II and III quarter) the concentration of metals was less and amounted to 39.92 mg·kg -1 d.m. and 37.80 mg·kg -1 d.m. respectively. Penetration of heavy metals and cement dust particles together with water into thallus results in die-back of algae layer cells what causes necrotic changes visible in outside structure of thallus.
Epilithic lichen communities in dry grasslands on calcareous substrata play important functional roles, which may be compromised by the impact of fire. Lichens are involved in both rock weathering and rock stabilization, these processes being directly related to soil formation. In this paper, we examined the hypothesis that the functional and the taxonomic diversity of epilithic lichen communities in Mediterranean dry grassland is influenced by both time since fire and fire frequency. These disturbances produced different effects on the functional richness and on the taxonomic diversity of the communities. Our findings revealed that: (1) a drastic reduction of biodiversity was caused by frequent fires in the same area; (2) that resulting lichen communities in burned sites were merely an impoverishment of unburned areas; and (3) that in the case of infrequent fires, lichen communities can recover functional diversity even if a reduction of taxonomic diversity occurs.
Lichens have been recognized as being very sensitive to air pollution for many years (Hawksworth 1971; Nimiset al. 2002). In the 1800s independent observations in England, Munich, and Paris documented that lichens were already disappearing from urban areas. By the early 1900s this “city” effect was a widely recognized phenomenon in Europe and was first attributed to coal dust, which was emitted by most homes as well as many industries. Only later did the colorless gas, sulfur dioxide, become recognized as a principal phytotoxic agent. Today the list of air pollutants is much longer and includes oxidants, hydrogen fluoride, some metals (Section 12.7), acid rain, and organics. Certainly the list of potentially toxic substances is not yet fully circumscribed. The high sensitivity of lichens is related to their biology. Most species live for decades or hundreds of years and a few longer; thus, as perennials, they are subject to the cumulative effect of pollutants. Lichens have no vascular system for conducting water or nutrients; as a consequence, they have developed efficient mechanisms for taking up water and nutrients from atmospheric sources. Fog and dew, major water sources for lichens, often have much higher pollutant concentrations than precipitation, and the lichens' nutrient concentration mechanisms also will concentrate pollutants. Unlike many vascular plants, lichens have no deciduous parts, and hence cannot avoid pollutant exposure by shedding such parts.
QuestionsHow resilient is boreal forest vegetation growing on acidic podzols to the environmental change caused by alkaline kiln dust pollution? How adaptive is the vegetation, when species pool and time for dispersal do not limit? How constant is the species niche breadth along the soil pH gradient? LocationRegion of 30 km around the Kunda cement plant, northern Estonia (59°30′ N, 26°32′ E), which has been continuously polluted last 140 years. Methods
We sampled 20 forest stands on sandy gleyic podzols at various distances from the pollution source, leeward and windward of prevailing winds. Data processing: principal components analysis for gradient generalization, indicator species analysis for grouping species along the pollution gradient and generalized linear model analyses to estimate species reaction to pollution, considering covariates. ResultsThe impact of alkaline dust accumulated over a century persisted despite resolute reductions of pollution. Forest soil conditions changed 10 km leeward and 5 km windward from the source: the litter pH level changed from 3.6 to 4.5 in unpolluted forests to 7.1–7.4 in the heavily polluted forests, and soil Ca content increased ten-fold. Soil alkalization has induced a remarkable succession from typical boreal vegetation toward vegetation of boreo-nemoral or calcareous habitats. We detected a linear increase of species richness from habitats on acidic soils (unpolluted) to newly formed alkaline soils (polluted habitats), reflecting the species pool composition and size, which is known to be large for calcicolous species. The establishment of several endangered calcicolous species shows the lack of dispersal limitation and points on their narrow soil pH niche. The niche breadth of species along the pH gradient varied among species, but only a few species appeared to be pH generalists. Conclusions
Species ranking along the pH and/or Ca gradients indicates (1) the existence of different ecological guilds in terms of ecological niche use, and (2) the formation of a new community is dictated by the tolerance level of each species. This supports the individualistic community assembly rule suggested by Gleason. We find that such polluted regions with disturbed communities have high scientific value as long-term ecological experiments, but this might lead to conflict between the peculiar biodiversity complex and human well-being.
The extent to which biodiversity change in local assemblages contributes to global biodiversity loss is poorly understood.
We analyzed 100 time series from biomes across Earth to ask how diversity within assemblages is changing through time. We
quantified patterns of temporal α diversity, measured as change in local diversity, and temporal β diversity, measured as
change in community composition. Contrary to our expectations, we did not detect systematic loss of α diversity. However,
community composition changed systematically through time, in excess of predictions from null models. Heterogeneous rates
of environmental change, species range shifts associated with climate change, and biotic homogenization may explain the different
patterns of temporal α and β diversity. Monitoring and understanding change in species composition should be a conservation
priority.
Despite their considerable relevance as biodiversity hotspots, alpine ecosystems are presently threatened by several anthropogenic disturbances. Among these, pasture-derived nitrogen deposition is expected to significantly alter community composition and diversity of many sensitive organisms, such as lichens. We analysed patterns of γ-diversity components in epilithic lichen communities of pasturelands in the Maritime Alps (north-west Italy). Our aims were: (1) to estimate the shift in functional groups for nitrogen tolerance along a gradient of increasing cattle load; (2) to establish the cattle critical load. High cattle load reduced the species replacement and significantly increased the similarity in the oligotrophic component of the lichen communities. The oligotrophic component was the most sensitive functional group to nitrogen. Based on the relative abundance of oligotrophs we set the cattle critical load of the area at 0.12 grazing animals per hectare.
The present study was undertaken with the aim of using epiphytic lichens as sentinels for air pollution at two remote alpine sites (1,400 and 1,800 m above sea level (asl)) of NW Italy. The results indicated that the site at 1,800 m prompted for early warning indications of biological changes. Although levels of the many elements assayed in samples of the lichen Pseudevernia furfuracea (L.) Zopf, ranging from minor elements (e.g., Al) to ultra-trace (e.g., Pt), were at normal levels, indications of a slowly worsening environment were given by the lichen biodiversity and by damage to cell membranes. The analysis of Pb isotopic ratios suggested that the origin of Pb accumulated in lichens is not local, but linked to the long-range transport by air masses. It was concluded that the origin of pollutants is from air mass coming from the Po plain of Italy and from densely populated areas of Switzerland and France.
The forest canopy is fundamentally important in biodiversity conservation and ecosystem function. Cryptogamic epiphytes are dominant tree bole and canopy elements in temperate and boreal forests, though remain neglected by mainstream forest ecology. This review makes ecological information on cryptogamic epiphytes available to a non-specialist audience, to facilitate their integration in forest biodiversity and ecosystem studies more generally. The review focuses specifically on lichen epiphytes, highlighting their diversity and ecosystem role. A principal task is to explore pattern and process in lichen epiphyte diversity – species composition and richness – therefore demonstrating the utility of lichens as an ecological model system. The review examines key themes in previous research. First, the extensive literature used to resolve species response to, and community turnover along environmental/resource gradients, consistent with the habitat niche. Second, the evidence for dispersal-limitation, which may constrain community composition and richness in isolated habitats. Third, these two processes – the habitat niche and dispersal-limitation – are used to explain stand-scale diversity, in addition to the role of neutral effects (habitat area). Fourth, the review moves from a taxonomic (pattern) to a functional (process) perspective, considering evidence for autogenic succession evidenced by competition and/or facilitation, and non-random trends in life-history traits. This functional approach provides a counter-point to an assumption that lichen epiphyte communities are unsaturated and non-competitive, a situation which would allow the long-term accumulation of species richness with temporal continuity. Finally, the review explores landscape-scale impacts on lichen epiphytes, with recommendations for conservation.
It is suggested that evolution in plants may be associated with the emergence of three primary strategies, each of which may be identified by reference to a number of characteristics including morphological features, resource allocation, phenology, and response to stress. The competitive strategy prevails in productive, relatively undisturbed vegetation, the stress-tolerant strategy is associated with continuously unproductive conditions, and the ruderal strategy is characteristic of severely disturbed but potentially productive habitats. A triangular model based upon the three strategies may be reconciled with the theory of r- and K-selection, provides an insight into the processes of vegetation succession and dominance, and appears to be capable of extension to fungi and to animals.
The relative impact of lichen photobiont and mycobiont was evaluated by submitting nine lichen species with: (i) different photobiont types; (ii) different lichen growth forms; and (iii) different nutrients, pH, humidity preferences; to a range of Cu concentrations (mu M) supplied in repeated cycles to simulate the natural process of uptake under field conditions. The physiological performance of the photosystem II photochemical reactions was measured using F(v)/F(m), and the metabolic activity of the mycobiont was evaluated using ergosterol and intracellular K-loss as indicators. Lichens with higher cation exchange capacity showed higher intracellular Cu uptake and their ecology seemed to be associated with low-nutrient environments. Thus the wall and external matrix, mainly characteristic of the mycobiont partner, cannot be ignored as the first site of interaction of metals with lichens. No common intracellular Cu concentration threshold was found for the physiological impacts observed in the different species. Most physiological effects of Cu uptake in sensitive lichens occurred for intracellular Cu below 200 mu g/g dw whereas more tolerant species were able to cope with intracellular Cu at least 3 times higher. Cyanobacterial lichens showed to be more sensitive to Cu uptake than green-algal lichens. Within the Trebouxia lichens, different species showed different sensitivities to Cu uptake, suggesting that the mycobiont may change the microenvironment close to the photobiont partner providing different degrees of protection. Despite the fact that the photobiont is the productive partner, the metabolic activity of the mycobiont of lichen species adapted to environments rich in nutrients, showed to be more sensitive to Cu uptake than the photochemical performance of the photobiont.
Survival strategies of 34 species of lichens from a range of substrata, climates and growth forms were examined using the triangular ordination procedure of Grime. Triangular ordination is apparently an appropriate technique to apply to lichens, all available data falling within a triangle except for two foliicolous species which are probably partial leaf parasites. Statistically significant relationships between survival strategy and growth form, mode of asexual reproduction, substratum preference, family affiliation, and diversity of secondary chemical biosynthetic pathways have been demonstrated.
1. Atmospheric ammonia (NH3) is one of the main drivers for ecosystem changes world-wide, including biodiversity loss. Modelling its deposition to evaluate its impact on ecosystems has been the focus of many studies. For that, universal indicators are needed to determine and compare the early effects of NH3 across ecosystems.
2. We evaluate the effects of atmospheric NH3 in ecosystems using lichens, which are one of the most sensitive communities at the ecosystem level. Rather than measuring total diversity, we use a functional diversity approach because this is potentially a more universal tool.
3. We evaluated the spatial and temporal patterns of atmospheric NH3 concentrations ([NH3]atm) emitted from a point-source over a 1-year period in a cork oak Mediterranean woodland. We observed a temporal pattern of [NH3]atm, with maximum concentrations during autumn.
4. The distribution of lichen species was c. 90% explained by [NH3]atm. The tolerance of lichen species to atmospheric NH3, based on expert knowledge from literature, was tested for the first time against direct measurements of atmospheric NH3. Most species were well classified, with the exception of Lecanora albella and Chrysothrix candelaris, which were more tolerant than expected. Our updated lichen classification can be used to establish lichen functional groups that respond to atmospheric NH3, and these can be used in other Mediterranean countries.
5. Increasing [NH3]atm led to a complete replacement of oligotrophic by nitrophytic species within 65 m of the NH3 source. The geostatistical analysis of functional diversity variables yielded a spatial model with low non-spatial variance, indicating that these variables can cope robustly with high spatial variation in NH3.
6. Synthesis and applications. Our results support the use of functional diversity variables, such as a lichen diversity value, as accurate and robust indicators of the effects of atmospheric NH3 on ecosystems. The spatial modelling of these indicators can provide information with high spatial resolution about the effects of atmospheric NH3 around point- and diffuse sources. As this methodology is based on functional groups, it can be applied to monitor both the impact of atmospheric NH3 and the success of mitigation strategies.