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Aims: The effect of biogeographical processes on the spatial turnover component of beta‐diversity over large spatial extents remains scarcely understood. Here, we aim at disentangling the roles of environmental and historical factors on plant taxonomic and phylogenetic turnover, while controlling for the effects of species richness and rarity. Location: European beech (Fagus sylvatica) forests in Europe. Methods: We aggregated plant species occurrences from vegetation plots in spatial grid cells of 0.25º × 0.25º to calculate the spatial turnover component of taxonomic (TBDturn) and phylogenetic (PBDturn) beta‐diversity for each cell. We also calculated the deviation of PBDturn given TBDturn (PBDdev‐turn), which measures the importance of phylogenetic turnover after factoring out taxonomic turnover. Beta‐diversity was calculated for each grid cell as the mean pairwise dissimilarity between the focal cell and all other cells. We used structural equation modeling (SEM) to examine the relationships between environmental (climate, soil pH, and distance from the geographical distribution limit of beech) and historical (distance from beech glacial refugia) predictors and beta‐diversity metrics. Results: We found a geographically consistent variation in taxonomic and phylogenetic turnover. Overall, TBDturn and PBDturn increased significantly toward more extreme climatic conditions, on more acidic soils, and toward the margins of beech distribution. The effects of environmental variables and the distance from glacial refugia on beta‐diversity metrics were mediated by species richness and rarity. Phylogenetic turnover was low in relation to taxonomic turnover (i.e., high PBDdev‐turn) in areas closer to glacial refugia. Conclusions: Continental‐scale patterns of beta‐diversity in European beech forests are the result of complementary ecological and evolutionary processes. In general, beech forests are taxonomically and phylogenetically more distinct in climatically marginal areas of their European range. However, the spatial variation of beta‐diversity in European beech forest flora is still strongly characterized by the distribution of groups of closely related species that evolved or survived in glacial refugia. [ABSTRACT FROM AUTHOR]

The Caucasus harbours unique forest vegetation so far only little studied using the Braun-Blanquet approach. This study is mostly based on a dataset (N = 110) of original phytosociological relevés of oak-hornbeam and ravine forests in the Eastern Greater Caucasus, Georgia. Their unsupervised classification produced seven communities. Five belong to oak-hornbeam forests (order Lathyro-Carpinetalia caucasicae). Of the zonal Caucasian alliance Crataego-Carpinion, the association Corno australis-Carpinetum inhabits valleys of the Greater Caucasus, and Clinopodio umbrosi-Carpinetum is confined to the warm Eastern Greater Caucasus promontories. The association Astrantio maximae-Carpinetum of the alliance Astrantio-Carpinion represents distinctive Caucasian montaneoak-hornbeam forests. The other two communities, documented by a few relevés, were described at the community level only. Within ravine forests (order Aceretalia pseudoplatani), we introduce a new Caucasian alliance Pachyphragmo macrophyllae-Tilion begoniifoliae with two associations. Valeriano tiliifoliae-Ulmetum glabrae comprises Caucasian montane ravine forests whereas Hedero pastuchovii-Aceretum velutini inhabits the foothills of the Eastern Greater Caucasian. To provide a broader context of the recognized communities, an expanded dataset (N = 231) of original relevés and previously published relevés of Georgian deciduous forests was analysed. It indicated a major turnover in species composition following biogeographical patterns presumably driven by macroclimate and vegetation history. [ABSTRACT FROM AUTHOR]

Aim: Current species‐richness patterns are sometimes interpreted as a legacy of landscape history, but historical processes shaping the distribution of species during the Holocene are frequently omitted in biodiversity models. Here, we test their importance in modelling current species richness of vascular plants in forest and grassland vegetation. Location: Western Carpathians and adjacent regions. Taxon: Vascular plants. Methods: Numbers of all species and of habitat specialists were extracted from plot records of forest and grassland vegetation. For each plot, environmental and historical data were derived from thematic maps. Historical data related to the persistence of (a) temperate taxa during the Late Glacial and Early Holocene, (b) open‐landscape taxa during the Middle Holocene and (c) taiga taxa during the Late Holocene were based on 112 fossil pollen profiles. Boosted regression trees were used to model spatial patterns in species richness. Results: Historical variables always appeared among the best predictors of current species richness. In light forests, species richness highly mirrored both the Late Glacial (12.5% contribution) and Middle‐Holocene (8.6%) landscape history. The latter factor became an important predictor also for species richness of steppe grasslands (8.3%) along with temperature seasonality (11.9%). Species richness of dark coniferous forests was best predicted by the Late‐Holocene occurrence of taiga forests (14.8%), which had an even stronger effect on the richness of habitat specialists (20.5%). Main conclusions: Landscape changes since the Last Glacial Maximum are important predictors of current plant species richness. The historical effects were found to be habitat specific and, because they may interact with recent environmental conditions and anthropogenic pressures, they often show a nonlinear relationship with species richness. We provide one possible direction of incorporating past landscape changes to the models of species richness. [ABSTRACT FROM AUTHOR]

Aims: The forest vegetation of Turkey has been studied extensively using the Braun-Blanquet approach, but mostly in rather small areas which were not sufficient to provide an integrative phytosociological interpretation. In this study, we formed a regional forest vegetation database and aimed to construct a hierarchical syntaxonomic system using numerical methods. Study area: The Western Euxine province of the Euro-Siberian phytogeographic region of Turkey, extending from the province of Sinop in the east to the Istranca Mountains in the west. Methods: Vegetation data consist of 1526 relevés and 872 species. The dataset was split into coniferous forests and deciduous-mixed forests. For the delimitation of these categories, all relevés where the total cover of deciduous trees reached at least 1/3 of the total cover of tree layer were defined as deciduous-mixed forests, while relevés with a total cover of deciduous trees less than 1/3 were defined as coniferous forests. Classification of these forests was carried out using TWINSPAN. Diagnostic species of vegetation units were defined using both the phi coefficient and constancy ratio. For tree species, the ratio of average cover was taken instead of constancy ratio. The vegetation units were further evaluated using DCA ordination and comparison of environmental variables. Results: The classification of deciduous-mixed forests resulted in 21 units differentiated by edaphic, climatic or phytogeographic factors. These communities were assigned to three classes (Quercetea pubescentis, Carpino-Fagetea, Alno-Populetea), four orders and five alliances. The oak-hornbeam forests of Turkey were described as a new alliance Trachystemono orientalis-Carpinion betuli since there was no valid alliance name available. For coniferous forests, eight communities were determined which are classifed in three classes (Quercetea ilicis, Erico-Pinetea, Vaccinio-Piceetea), three orders and three alliances. Mesic fir forests were assigned to a new alliance Lonicero caucasicae-Piceion orientalis within a new order Abieti nordmannianae-Piceetalia orientalis. Conclusions: In separating coniferous and deciduous-mixed forests prior to the numerical classification, we were able to achieve a classification in good accordance with the current syntaxonomic system used in Europe. The proposed system of higher syntaxa, which is mainly based on the dominant tree species, will provide a more stable and objective framework for future studies on biodiversity, nature conservation and sustainable forest management. Moreover, we provide an overview of the associations corresponding to each vegetation unit. [ABSTRACT FROM AUTHOR]

In this paper we present nomenclatural adjustments and validations of syntaxa of the forest vegetation of Europe. We introduce a new, valid name of the class of nemoral coniferous or mixed forests ( Asaro europaei-Abietetea sibiricae) replacing the deciduous Carpino-Fagetea in the easternmost Europe and Siberia. We describe two new orders for birch and birch-poplar woodlands, formerly included in the Betulo pendulae-Populetalia tremulae. We validate the names of two alliances for the deciduous forests of the Southern Urals and the name of an alliance for hemiboreal forest swamps. The suballiance Ostryo-Tilienion, coined to accommodate the xerothermophilous ravine forests of SE Europe, is here elevated to the rank of alliance. Finally, we validate the name Quercion alnifoliae (evergreen oak forests of Cyprus). [ABSTRACT FROM AUTHOR]

. Question: Are there effects of long-term deposition of airborne nitrogen and sulphur on the forest floor vegetation from permanent plots collected in 1993 compared to 2005. Location: Northern limestone Alps in Austria. Methods: Single species responses were analysed by correlating trends in cover-abundance values, as derived from marginal models, with Ellenberg indicator values. Changes in the species composition of plots were analysed by correlating changes in mean Ellenberg indicator values with the displacement of plots within a multidimensional scaling ordination. Results: Trends in single species abundance were positively correlated with indicator values of soil pH but were independent of nutrient availability. A general trend towards the homogenisation of vegetation, due to convergent time vectors of the relevés, became obvious. Oligotrophic sites previously situated at the distal ends of ordination axes shifted towards the centre since they were enriched by species preferring mesotrophic conditions. The bulk of plots with intermediate site conditions hardly showed any trends. A concomitant analysis demonstrated that temporal changes in species composition exceed the variation in cover abundance estimates among different field botanists. Conclusions: N deposition can lead to a homogenisation of forest floor vegetation. Larger limestone areas with diverse soil conditions, such as the Northern limestone Alps in Austria, as a whole are thus negatively affected by airborne N deposition. Nevertheless, the vegetation was at least as strongly affected by an increase of basiphilous species as a result of decreasing S deposition. [ABSTRACT FROM AUTHOR]