The European Vegetation Archive (EVA) is a centralized database of European vegetation plots developed by the IAVS Working Group European Vegetation Survey. It has been in development since 2012 and first made available for use in research projects in 2014. It stores copies of national and regional vegetation‐ plot databases on a single software platform. Data storage in EVA does not affect on‐going independent development of the contributing databases, which remain the property of the data contributors. EVA uses a prototype of the database management software TURBOVEG 3 developed for joint management of multiple databases that use different species lists. This is facilitated by the SynBioSys Taxon Database, a system of taxon names and concepts used in the individual European databases and their corresponding names on a unified list of European flora. TURBOVEG 3 also includes procedures for handling data requests, selections and provisions according to the approved EVA Data Property and Governance Rules. By 30 June 2015, 61 databases from all European regions have joined EVA, contributing in total 1 027 376 vegetation plots, 82% of them with geographic coordinates, from 57 countries. EVA provides a unique data source for large‐scale analyses of European vegetation diversity both for fundamental research and nature conservation applications. Updated information on EVA is available online at http://euroveg.org/eva-database.

Questions: What are the main floristic patterns in the Pannonian and western Pontic steppe grasslands? What are the diagnostic species of the major subdivisions of the class Festuco‐Brometea (temperate Euro‐Siberian dry and semi‐dry grasslands)?Location: Carpathian Basin (E Austria, SE Czech Republic, Slovakia, Hungary, Romania, Slovenia, N Croatia and N Serbia), Ukraine, S Poland and the Bryansk region of W Russia.Methods: We applied a geographically stratified resampling to a large set of relevés containing at least one indicator species of steppe grasslands. The resulting data set of 17 993 relevés was classified using the TWINSPAN algorithm. We identified groups of clusters that corresponded to the class Festuco‐Brometea. After excluding relevés not belonging to our target class, we applied a consensus of three fidelity measures, also taking into account external knowledge, to establish the diagnostic species of the orders of the class. The original TWINSPAN divisions were revised on the basis of these diagnostic species.Results: The TWINSPAN classification revealed soil moisture as the most important environmental factor. Eight out of 16 TWINSPAN groups corresponded to Festuco‐Brometea. A total of 80, 32 and 58 species were accepted as diagnostic for the orders Brometalia erecti, Festucetalia valesiacae and Stipo‐Festucetalia pallentis, respectively. In the further subdivision of the orders, soil conditions, geographic distribution and altitude could be identified as factors driving the major floristic patterns.Conclusions: We propose the following classification of the Festuco‐Brometea in our study area: (1) Brometalia erecti (semi‐dry grasslands) with Scabioso ochroleucae‐Poion angustifoliae (steppe meadows of the forest zone of E Europe) and Cirsio‐Brachypodion pinnati (meadow steppes on deep soils in the forest‐steppe zone of E Central and E Europe); (2) Festucetalia valesiacae (grass steppes) with Festucion valesiacae (grass steppes on less developed soils in the forest‐steppe zone of E Central and E Europe) and Stipion lessingianae (grass steppes in the steppe zone); (3) Stipo‐Festucetalia pallentis (rocky steppes) with Asplenio septentrionalis‐Festucion pallentis (rocky steppes on siliceous and intermediate soils), Bromo‐Festucion pallentis (thermophilous rocky steppes on calcareous soils), Diantho‐Seslerion (dealpine Sesleria caerulea grasslands of the Western Carpathians) and Seslerion rigidae (dealpine Sesleria rigida grasslands of the Romanian Carpathians).

Questions: Which are the main wet and mesic grassland vegetation types along the climatic gradient on the southern margin of the Pannonian basin? Which are the most important environmental gradients that determine their distribution and species composition?Location: The southern margin of the Pannonian plain (N and E Slovenia, N Croatia, N Serbia).Methods: A database of 2,575 vegetation plots originally assigned to the Molinio‐Arrhenatheretea was compiled. Semi‐supervised classification based on the K‐means algorithm was applied to assign plots into 12 a‐priori alliances and to search for new alliances. Non‐metric Multidimensional Scaling (NMDS) ordination with Ellenberg's indicator values and bioclimatic variables were applied to show the influence of ecological conditions on species composition. The plots within each alliance were further classified into associations using the beta flexible method.Results: Classification resulted in 12 alliances recognized in the EuroVegChecklist, and two new groups appeared. The first group occurs in the eastern part of the research area, where many ruderal species appear. This group was treated as a new alliance, Salvio nemorosae‐Arrhenatherion forming a vicariant syntaxon of the alliance Arrhenatherion. The second group occurs in the western part. It is a transitional group between mesic (Arrhenatherion) and wet meadows (Deschampsion) and can be treated as Alopecurion. Besides, three new associations and six new subassociations were described, together with the typification of seven associations and of three subassociations. Numerical analyses revealed floristic, ecological and geographical differentiation among analysed vegetation types.Conclusions: The communities showed typical Central European features in the western part, but their floristic and ecological conditions changed towards the eastern part, where the continental influence was more pronounced. The vegetation structure and plant species composition in the studied area were influenced by soil moisture and soil nutrient availability as well as by strong biogeographical and climatic gradients.

Walls represent globally distributed, locally extensive, artificial ecosystems. Wall vegetation is still poorly known in the Mediterranean and Temperate regions of southeastern Europe. The aim of this study is to classify and describe chasmophytic vegetation of walls, covering southeastern Europe from Slovenia to North Macedonia. From a total 463 phytosociological relevés, we identify and describe 12 distinct species-poor to moderately rich vegetation units using TWINSPAN evaluated by NMDS, and indicator values. The vegetation units are included within three alliances from two macroclimate regions: (i) vegetation of cool-temperate Europe of the Cymbalario-Asplenion alliance, and (ii) Mediterranean vegetation of the Galio valantiae-Parietarion judaicae and Artemisio arborescentis-Capparidion spinosae alliances. The southernmost limit of the Cymbalario-Asplenion was determined in Central Bosnia. The presence of the Artemisio arborescentis-Capparidion spinosae in the eastern Adriatic is highlighted.

The impact of meteorological conditions on in vitro pollen germination and pollen tube growth during the initial phases of the development of male flowers in the Pedunculate Oak, Quercus robur, is studied. Phenological observations of male flowers and pollen sampling were performed on the field trial established with grafted Pedunculate Oak clones. During the investigation, weather conditions (absolute minimum and maximum daily air temperature, minimum absolute relative humidity of air and amount of precipitation) were recorded by an automatic meteorological station installed at the field trial. Influence of meteorological conditions on pollen germination and pollen tube growth was studied in the following stages of male flower: (I) during the last ten days of flower bud dormancy, (II) during swelling of the buds, (III) during bud burst and beginning of male catkins elongation, (IV) during the final stage of male flower catkins elongation. High temperatures and low relative air humidity during the bud burst and beginning of the male catkins elongation reduced pollen germination and pollen tube growth. Weather conditions did not significantly affect pollen germination and pollen tube growth during the swelling of flower buds, or in the final stage of male catkins elongation.