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AimUrban floras are composed of species of different origin, both native and alien, and with various traits and niches. It is likely that these species will respond to the ongoing climate change in different ways, resulting in future species compositions with no analogues in current European cities. Our goal was to estimate potential shifts in plant species composition in European cities under different scenarios of climate change for the 21st century.LocationEurope.MethodsPotential changes in the distribution of 375 species currently growing in 60 large cities in Southern, Central and Western Europe were modelled using generalized linear models and four climate change projections for two future periods (2041–2060 and 2061–2080). These projections were based on two global climate models (CCSM4 and MIROC‐ESM) and two Representative Concentration Pathways (2.6 and 8.5).ResultsResults were similar across all climate projections, suggesting that the composition of urban plant communities will change considerably due to future climate change. However, even under the most severe climate change scenario, native and alien species will respond to climate change similarly. Many currently established species will decline and others, especially annuals currently restricted to Southern Europe, will spread to northern cities. In contrast, perennial herbs, woody plants and most species with temperate continental and oceanic distribution ranges will make up a smaller proportion of future European urban plant communities in comparison with the present communities.Main conclusionsThe projected 21st century climate change will lead to considerable changes in the species composition of urban floras. These changes will affect the structure and functioning of urban plant communities.

Aims: Ellenberg-type indicator values are expert-based rankings of plant species according to their ecological optima on main environmental gradients. Here we extend the indicator-value system proposed by Heinz Ellenberg and co-authors for Central Europe by incorporating other systems of Ellenberg-type indicator values (i.e., those using scales compatible with Ellenberg values) developed for other European regions. Our aim is to create a harmonized data set of Ellenberg-type indicator values applicable at the European scale.Methods: We collected European data sets of indicator values for vascular plants and selected 13 data sets that used the nine-, ten-or twelve-degree scales defined by Ellenberg for light, temperature, moisture, reaction, nutrients and salinity. We compared these values with the original Ellenberg values and used those that showed consistent trends in regression slope and coefficient of determination. We calculated the average value for each combination of species and indicator values from these data sets. Based on species' co-occurrences in European vegetation plots, we also calculated new values for species that were not assigned an indicator value. Results: We provide a new data set of Ellenberg-type indicator values for 8908European vascular plant species (8168 for light, 7400 for temperature, 8030 for

Aims: Vegetation-plot sampling usually involves estimating species cover. For classifying plots to vegetation types, covers are often transformed to decrease the effect of dominant species. However, it remains unclear which transformation is optimal. We suggest that for vegetation classification, optimal is such transformation that contributes to creating clusters of plots in an unsupervised classification that are most similar to the widely accepted vegetation types, e.g., phytosociological associations. Here our aim is to find and recommend such optimal transformation by testing a range of transformation options against the national vegetation classifications of three European countries.

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Aim The first comprehensive checklist of European phytosociological alliances, orders and classes (EuroVegChecklist) was published by Mucina et al. (2016, Applied Vegetation Science, 19 (Suppl. 1), 3–264). However, this checklist did not contain detailed information on the distribution of individual vegetation types. Here we provide the first maps of all alliances in Europe. Location Europe, Greenland, Canary Islands, Madeira, Azores, Cyprus and the Caucasus countries. Methods We collected data on the occurrence of phytosociological alliances in European countries and regions from literature and vegetation‐plot databases. We interpreted and complemented these data using the expert knowledge of an international team of vegetation scientists and matched all the previously reported alliance names and concepts with those of the EuroVegChecklist. We then mapped the occurrence of the EuroVegChecklist alliances in 82 territorial units corresponding to countries, large islands, archipelagos and peninsulas. We subdivided the mainland parts of large or biogeographically heterogeneous countries based on the European biogeographical regions. Specialized alliances of coastal habitats were mapped only for the coastal section of each territorial unit. Results Distribution maps were prepared for 1,105 alliances of vascular‐plant dominated vegetation reported in the EuroVegChecklist. For each territorial unit, three levels of occurrence probability were plotted on the maps: (a) verified occurrence; (b) uncertain occurrence; and (c) absence. The maps of individual alliances were complemented by summary maps of the number of alliances and the alliance–area relationship. Distribution data are also provided in a spreadsheet. Conclusions The new map series represents the first attempt to characterize the distribution of all vegetation types at the alliance level across Europe. There are still many knowledge gaps, partly due to a lack of data for some regions and partly due to uncertainties in the definition of some alliances. The maps presented here provide a basis for future research aimed at filling these gaps.

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Csiky J., Onyshchenko V. & Chytrý M. (2020) Oak-hornbeam forests in central Europe: a formalized classification and syntaxonomic revision. -Preslia 92: 1-34Oak-hornbeam forests (order Carpinetalia) are a widespread vegetation type in central Europe. As vegetation ecologists focused on them since the pioneering times of vegetation research, many syntaxonomic units are described. However, classification systems used in various central-European countries suffer from inconsistencies and overlaps of the concepts of particular associations. Currently there is no consistent syntaxonomic system based on numerical analysis of vegetation plots that would be valid for the whole of central Europe. Therefore, the main goal of this study is to provide a revised syntaxonomic system of oak-hornbeam forests across central Europe, develop formal definitions of the associations and include these definitions in a classification expert system. We recognized 13 associations, 9 from the alliance Carpinion betuli (central-European oakhornbeam forests) and four from the alliance Erythronio-Carpinion (Illyrian and northern Italian oak-hornbeam forests). We prepared an expert system that classified 55% of the relevés in a central-European oak-hornbeam forest dataset (n = 6212) at the association level. To stabilize the Carpinion betuli association names, we selected nomenclatural type relevés for associations that have not been typified so far. In addition, two association names (Poo chaixii-Carpinetum and Pseudostellario-Carpinetum) were validated. Ordination revealed the main drivers of species diversity in these forests, including a complex gradient of soil moisture, nutrient availability and geographical position (mainly latitude). Among the climate variables, annual temperature amplitude and mean annual temperature were most closely correlated with species composition. K e y w o r d s: Carpinetalia betuli, Carpinion betuli, classification expert system, Erythronio-Carpinion, formalized vegetation classification, syntaxonomy, temperate broad-leaved deciduous forests