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Harsh environmental conditions form habitats colonized by specialized primary microbial colonizers, e.g., biological soil crusts (biocrusts). These cryptogamic communities are well studied in drylands but much less in temperate coastal dunes, where they play a crucial role in ecological functions. Following two dune chronosequences, this study highlights the successional development of the biocrust's community composition on the Baltic Sea coast. A vegetation survey, followed by morphological species determination, was conducted. Sediment/soil cores of the different dune types were analyzed to uncover the potential impacts of the biocrust community on initial soil formation processes, with special emphasis on biogeochemical phosphorous (P) transformations. Biocrust succession was characterized by a dune type-specific community composition, shifting from thinner algae-dominated biocrusts in dynamic dunes to more stable moss-dominated biocrusts in mature dunes. The change in the biocrust community structure was accompanied by an increase in Chl a, water, and organic matter content. In total, 25 algal and cyanobacterial species, 16 mosses, and 26 lichens across all sampling sites were determined. The pedological characterization of these cores elucidated initial processes of soil genesis, such as decalcification, acidification, and the accumulation of organic matter with dune and biocrust development. Furthermore, the chemistry of iron (Fe)- containing compounds such as the Fedithionite/Fetotal ratios confirmed mineral weathering and the beginning of soil profile development. The biocrusts accumulated P over time, while the P content in the underlying sediment did not change. That implies that biocrusts take up P from the geological parent material in the dunes, thereby accumulating available P in the ecosystem, which gets transferred into subsoil horizons through leaching or redeposition. The relative proportion of the bioavailable P pool (56% to 74% of Pt) increased with dune succession. That happened at the expense of more stable bound P, which was transformed into labile P. Thus, the level of plant available P along the dune chronosequences increased due to the microbial activity of the biocrust organisms. It can be concluded that biocrusts of temperate coastal dunes play a crucial role in maintaining their habitat by accumulating nutrients and organic matter, supporting soil development and subsequent vegetation. [ABSTRACT FROM AUTHOR]

Simple Summary: This publication focuses on a comparative biodiversity survey of cryptogamic covers along a dune chronosequence in the Baltic Sea compared to an inland dune in northern Germany. Following these gradients, the cryptogamic vegetation accumulated more and more biomass and nutrients (carbon, nitrogen, and phosphorus). Further, a habitat-specific phototrophic community composition could be revealed. The enrichment of the biotic and abiotic components suggests cryptogamic covers as key players in geochemical processes, supporting sediment moisture and stability. Moreover, it highlights these communities as 'ecosystem engineers' playing a valuable part in nature protection e.g., preventing sediment erosion in coastal dune areas. (1) Biological soil crusts (biocrusts) are microecosystems consisting of prokaryotic and eukaryotic microorganisms growing on the topsoil. This study aims to characterize changes in the community structure of biocrust phototrophic organisms along a dune chronosequence in the Baltic Sea compared to an inland dune in northern Germany. (2) A vegetation survey followed by species determination and sediment analyses were conducted. (3) The results highlight a varying phototrophic community composition within the biocrusts regarding the different successional stages of the dunes. At both study sites, a shift from algae-dominated to lichen- and moss-dominated biocrusts in later successional dune types was observed. The algae community of both study sites shared 50% of the identified species while the moss and lichen community shared less than 15%. This indicates a more generalized occurrence of the algal taxa along both chronosequences. The mosses and lichens showed a habitat-specific species community. Moreover, an increase in the organic matter and moisture content with advanced biocrust development was detected. The enrichment of carbon, nitrogen, and phosphorus in the different biocrust types showed a similar relationship. (4) This relation can be explained by biomass growth and potential nutrient mobilization by the microorganisms. Hence, the observed biocrust development potentially enhanced soil formation and contributed to nutrient accumulation. [ABSTRACT FROM AUTHOR]

Lecanora s. lat. is a genus of crustose, rarely placodioid lichens comprising c. 1000 recognized species and subdivided into several morphology-based groups. Some of these groups have been supported in phylogenetic analyses and segregated as new genera. One of the remaining groups that has not been previously studied by molecular methods in much detail, the L. saligna-group, includes corticolous and lignicolous crustose lichens, usually containing isousnic or usnic acid (or both) as major secondary metabolites. As part of our ongoing project 'Lecanomics', a phylogenetic analysis based on two loci was conducted and found the L. saligna-group to be divided into two main clades and several well-supported minor clades. The L. varia clade, chosen as one of the outgroups, emerged within the L. saligna-group. The majority of the clades are characterized by phenotypic differences. However, several well-supported clades share similarities with their sister groups, suggesting that species circumscriptions based solely on phenotypic characters may be too conservative to characterize the true species diversity present within the group. Also, there is evidence for some geographical separation of lineages; for example, most North American individuals, previously known as Lecanora saligna and L. albellula, form two clades separate from their European namesakes and are here preliminarily called 'Lecanora sp. B', 'Lecanora sp. C' and 'Lecanora sp. D'. However, L. saligna and L. albellula also appear to occur in North America, and some specimens from the Caucasus and Iran cluster within the North American clades. Lecanora anopta and L. subravida are reported for the first time from Iran. [ABSTRACT FROM AUTHOR]

The past and present distribution of Lobaria pulmonaria in Denmark, northern Germany, northwestern Poland and nemoral parts of Skåne, Blekinge, southwesternmost Småland and southern Öland (Sweden) has been studied. Of 124 localities visited between 2015 and 2018, L. pulmonaria was confirmed at 64 sites, at each of which its habitat ecology and viability were investigated. It is almost extinct in Schleswig-Holstein, in southern Jutland, on the Danish Islands, in southwestern Skåne, in Mecklenburg-Vorpommern and in the western part of Pomerania. It has disappeared almost completely from areas where mesophytic forests form the potential natural vegetation. The commonest habitats for L. pulmonaria are species-poor acidic beech and species-poor oak forests, and the commonest substrates are trunks of beech, followed by oak. L. pulmonaria specimens on about two thirds of the colonized trees were in a healthy condition. The situation is worst in Schleswig-Holstein and on the Danish Islands, but best in Blekinge and central and northern Jutland. Recent distribution seems to be influenced by both anthropogenic (e.g. air pollution by sulphur dioxide and nitrogen and forestry practices) and natural factors (precipitation, temperature, air humidity), as well as unnatural climatic factors (global warming). [ABSTRACT FROM AUTHOR]

Aim: Species–area relationships (SARs) are fundamental scaling laws in ecology although their shape is still disputed. At larger areas, power laws best represent SARs. Yet, it remains unclear whether SARs follow other shapes at finer spatial grains in continuous vegetation. We asked which function describes SARs best at small grains and explored how sampling methodology or the environment influence SAR shape. Location: Palaearctic grasslands and other non‐forested habitats. Taxa: Vascular plants, bryophytes and lichens. Methods: We used the GrassPlot database, containing standardized vegetation‐plot data from vascular plants, bryophytes and lichens spanning a wide range of grassland types throughout the Palaearctic and including 2,057 nested‐plot series with at least seven grain sizes ranging from 1 cm2 to 1,024 m2. Using nonlinear regression, we assessed the appropriateness of different SAR functions (power, power quadratic, power breakpoint, logarithmic, Michaelis–Menten). Based on AICc, we tested whether the ranking of functions differed among taxonomic groups, methodological settings, biomes or vegetation types. Results: The power function was the most suitable function across the studied taxonomic groups. The superiority of this function increased from lichens to bryophytes to vascular plants to all three taxonomic groups together. The sampling method was highly influential as rooted presence sampling decreased the performance of the power function. By contrast, biome and vegetation type had practically no influence on the superiority of the power law. Main conclusions: We conclude that SARs of sessile organisms at smaller spatial grains are best approximated by a power function. This coincides with several other comprehensive studies of SARs at different grain sizes and for different taxa, thus supporting the general appropriateness of the power function for modelling species diversity over a wide range of grain sizes. The poor performance of the Michaelis–Menten function demonstrates that richness within plant communities generally does not approach any saturation, thus calling into question the concept of minimal area. [ABSTRACT FROM AUTHOR]

We asked: (i) Which environmental factors determine the level of α-diversity at several scales and β-diversity in steppic grasslands? (ii) How do the effects of environmental factors on α- and β-diversity vary between the different taxonomic groups (vascular plants, bryophytes, lichens)? We sampled nested-plot series ranging from 0.0001 to 100 m and additional 10-m plots, covering different vegetation types and management regimes in steppes and semi-natural dry grasslands of Central Podolia (Ukraine). We recorded all terricolous taxa and used topographic, soil, land-use and climatic variables as predictors. Richness-environment relationships at different scales and across taxonomic groups were assessed with multimodel inference. We also fitted power-law species-area relationships, using the exponent ( z value) as a measure of β-diversity. In general, the richness values in the study region were intermediate compared to those known from similar grasslands throughout the Palaearctic, but for 1 cm we found seven species of vascular plants, a new world record. Heat index was the most important factor for vascular plants and bryophytes (negative relation), while lichen diversity depended mainly on stone and rock cover (positive). The explanatory power of climate-related variables increased with increasing grain size, while anthropogenic burning was the most important factor for richness patterns at the finest grain sizes (positive effect). The z values showed more variation at the finest grain sizes, but no significant differences in their mean between scales. The results highlight the importance of integrating scale into ecological analyses and nature conservation assessments in order to understand and manage biological diversity in steppe ecosystems. [ABSTRACT FROM AUTHOR]

Cladonia rei and Cladonia subulata are morphologically similar, but chemically different cup lichens of dry grasslands and nutrient-poor ruderal habitats. Recently, C. rei has been synonymized with C. subulata on the basis of combined morphological and chemical investigations. However, doubts remained due to a molecular divergent North American sample of C. rei compared to European C. subulata. To clarify the situation, using molecular methods, we analysed chemically different European samples of C. rei and C. subulata, as well as other morphologically or chemically similar Cladonia species. Molecular data show that European and North American samples of C. rei belong to the same clade, which is closely related to C. fimbriata and followed by a subclade with C. coniocraea and C. ochrochlora. The subclade of C. subulata appears to be distinct from C. rei. In concordance with molecular data, the presence of homosekikaic acid is the determining chemical feature for C. rei. In addition, C. humilis and C. innominata proved to be molecularly distinct species. [ABSTRACT FROM AUTHOR]

Coastal dune ecosystems are among the most dynamic habitats with high conservation value in Europe but are also under strong anthropogenic pressure regarding coastal protection and recreation. Hence, it is of high importance to know about long-term natural and anthropogenic changes and development of protected dune habitats for nature conservation, as well as for coastal management. This paper aims to identify the vegetation dynamics on the Łeba Bar/Poland over a period of 74 years by cartometric comparison using modern Geographical Information System (GIS). To quantify the rate of vegetation dynamics two aerial photographs dating from 1932 and 2006 were digitalized and analyzed with GIS to produce digital vegetation maps. Information about decrease, increase and stability of vegetation types of this area are discussed. The results show that there has been a clear reduction in the total area of bare sand and a considerable increase of woodlands and dense grass communities. Nevertheless, the remaining extensive drift sand areas and deflation hollows on the Łeba Bar offer one of the most important habitats for pioneer vegetation on bare sand of migrating dunes and dunes at the Southern Baltic coast. The present work proved the need to observe the future development of the vegetation communities and to implement management measures to maintain the dynamic of this unique dune landscape. [ABSTRACT FROM AUTHOR]

Question: While it is well known that species richness depends on plot size, it is not generally recognised that the same must be true for constancy. Accordingly, many authors use varying plot sizes when classifying vegetation based on the comparison of constancies between groups of plots. We ask whether the constancy-area relationship follows a general rule, how strong the effect of plot sizes is on constancies, and if it is possible to correct constancies for area. Location: For empirical evaluation, we use data from plant communities in the Czech Republic, Sweden and Russia. Methods: To assess the potential influence of differences in plot size on constancies, we develop a mathematical model. Then, we use series of nested plot species richness data from a wide range of community types (herbaceous and forest) to determine the parameters of the derived function and to test how much the shape of the constancy-area relationship depends on taxa or vegetation types. Results: Generally, the constancy-area relationship can be described by C ( A)=1−(1− C0)( A/ A0)^ d, with C being constancy, A area, C0 known constancy on a specific area A0, and d a damping parameter accounting for spatial autocorrelation. As predicted by this function, constancies in plant communities always varied from values near 0% to near 100% if plot sizes were changed sufficiently. For the studied vegetation types, a two- to fourfold increase in plot size resulted in a change of conventional constancy classes, i.e. an increase of constancy by 20% or more. Conclusions: Vegetation classification, which largely relies on constancy values, irrespective of whether traditional or modern fidelity definitions are used, is strongly prone to distorting scale effects when relevés of different plot sizes are combined in studies. The constancy-area functions presented allow an approximate transformation of constancies to other plot sizes but are flawed by idiosyncrasies in taxa and vegetation types. Thus, we conclude that the best solution for future surveys is to apply uniform plot sizes within a few a priori delimited formations and to determine diagnostic species only within these formations. Finally, we suggest that more detailed analyses of constancy-area relationships can contribute to a better understanding of species-area relationships because the latter are the summation of the first for all species. [ABSTRACT FROM AUTHOR]

The species-area relationship (SAR) is one of the most frequently described patterns in biodiversity; however, it is seldom applied in conservation practice. Awareness of some shortcomings such as scale dependency is the basis for a better understanding of biodiversity patterns and a way to cope with artifacts occurring in empirical data. We demonstrate effects of scale dependency within plant communities deriving from different scale ranges, extreme values and curve intersections on empirical data of forest and grassland communities and propose to reduce the effect of scale dependence and artifacts of the SAR within plant communities by using limited scale ranges. Due to scale dependence, an appropriate limited scale range should be chosen, depending on vegetation type and realized scale range of the considered data set. Species-area curves based on the standard Whittaker plots for plant communities could act as references to assess species richness of the large pool of vegetation records of different sizes and provide a tool for ranking species diversity for grassland and forest communities, where vegetation records differ considerably in plot size. [ABSTRACT FROM AUTHOR]

Sixteen species of lichens and 5 species of lichenicolous fungi are reported as new to Lithuania: Absconditella sphagnorum, Arthonia apatetica, Bryophagus gloeocapsa, Carbonea vitellinaria, Catillaria chalybeia, Clauzadea monticola, Cyphelium tigillare, Dermatocarpon luridum, Lecania turicensis, Lecanora agardhiana, L. norvegica, L. persimilis, Lecidella carpathica, Leptogium byssinum, Placidium squamulosum, Pronectria pertusariicola, Pyrenochaeta xanthoriae, Refractohilum peltigerae, Trapelia involuta, Usnea wasmuthii, Vezdaea rheocarpa. Chaenotheca hispidula is reported to be re-found for the first time since the 1930-es. Bryophagus gloeocapsa, Lecanora agardhiana, Pronectria pertusariicola, Pyrenochaeta xanthoriae, Vezdaea rheocarpa are recorded for the first time in the Baltic states. Short characteristics of the collected specimens are given as well as notes about species ecology and distribution, especially in the Baltic region. [ABSTRACT FROM AUTHOR]