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Theories explaining community assembly assume that biotic and abiotic filters sort species into communities based on the values of their traits and are thus based on between‐species trait variability (BTV). Nevertheless, these filters act on individuals rather than on species. Consequently, the selection is also influenced by intraspecific trait variability (ITV) and its drivers. These drivers may be abiotic (e.g., water availability) or biotic (e.g., competition). Although closely related species should have similar traits, many of them coexist. We investigated the relative magnitudes of BTV and ITV in coexisting closely related species and how their individual traits differ under different drivers of ITV. We manipulated conditions in a greenhouse pot experiment with four common Carex species, where individuals of each species originated from four source localities. Individuals were grown in factorial combinations of two moisture levels, with and without a competitor (grass species Holcus lanatus, a frequent competitor). We analyzed the variability of six morphological traits on individuals in the greenhouse and three morphological traits in the source localities. Species identity was the main determinant of differences in most traits. Competition exerted a greater effect than water availability. For leaf dry matter content (LDMC) and vegetative height, competition's effect even exceeded the variability among species. On the contrary, for specific leaf area (SLA) and clonal spread, the interspecific differences exceeded ITV induced by experimental treatments. SLA measured in the greenhouse closely correlated with values measured in field populations, while LDMC did not. The variability caused by source locality of ramets in the greenhouse was small, although sometimes significant. Closely related species differ in their traits, but for some traits, ITV can exceed BTV. We can expect that ITV can modify the processes of community assembly, particularly among coexisting closely related species. [ABSTRACT FROM AUTHOR]

A growing number of studies have demonstrated that biodiversity is a strong and positive predictor of ecosystem temporal stability by simultaneously affecting multiple underlying mechanisms of stability, that is dominance, asynchrony and averaging effects. However, to date, no study has disentangled the relative role of these key mechanisms of stability in biodiversity experiments.We created a species richness gradient by mimicking a loss of rare species and assessed the role of species richness on community stability and, more importantly, quantified the relative role of three stabilizing mechanisms, that is dominance (stabilization due to stable dominants compared to the rest of the species in the community), asynchrony (stabilization due to temporal asynchrony between species), and averaging effects (pure effect of diversity) on community stability across a species richness gradient.We found that extreme species loss negatively impacted community stability, but just three species were enough to stabilize biomass production to a level similar to highly diverse communities. However, the similar stability of communities resulted from differing contributions from each stabilizing mechanism, depending on the community diversity. Since less abundant species were more temporally variable, species loss stabilized the populations of the remaining species. The loss of rare and subordinate species reduced the dominance and averaging effects, but increased the asynchrony effect. Hence, the asynchrony effect played a major role in the stability of species poor communities, while the averaging effect drove most of the stability of species rich communities. Overall, dominance played only a minor role, accounting for 5%–15% of the stabilization, while asynchrony and averaging effects were dominating forces contributing to ~85%–95% of the total stabilization.Synthesis. This study highlights the importance of biodiversity and roles of dominant and rare species for long‐term community stability and, for the first time, disentangles relative roles of dominance effect, asynchrony and averaging effect on community stability in a real‐world biodiversity experiment. [ABSTRACT FROM AUTHOR]

This article describes FloraVeg.EU, a new online database with open‐access information on European vegetation units (phytosociological syntaxa), vegetated habitats, and plant taxa. It consists of three modules. (1) The Vegetation module includes 149 phytosociological classes, 378 orders and 1305 alliances of an updated version of the EuroVegChecklist modified based on the decisions of the European Vegetation Classification Committee. Vegetation units dominated by vascular plants are characterized by country‐based distribution maps and data on the dominant life forms, phenology, soil properties, relationships to vegetation regions, elevational vegetation belts and azonal habitats, successional status, and degree of naturalness. A list of diagnostic taxa is also provided for each class. (2) The Habitats module includes vascular‐plant‐dominated terrestrial, freshwater, and marine habitat types from the first to the third or fourth highest hierarchical levels of the EUNIS classification. Of these, 249 vegetated habitats are characterized by a brief description, a point‐based distribution map, diagnostic, constant, and dominant taxa, and a list of the corresponding alliances. (3) The Species module provides information on 37 characteristics of European vascular plant species and some infrageneric or infraspecific taxa, including functional traits (habitus and growth type, leaf, flower, fruit and seed traits, and trophic mode), taxon origin (native vs alien), and ecological information (environmental relationships, Ellenberg‐type indicator values, disturbance indicator values, and relationships to vegetation units and habitat types). Values for at least three variables are available for 36,404 species. Individual taxa, vegetation units, and habitats in these three modules are illustrated by more than 34,000 photographs. The Download section of FloraVeg.EU provides open‐access data sets in a spreadsheet format that can be used for analyses. FloraVeg.EU is a new resource with easily accessible data that can be used for research in vegetation science, ecology, and biogeography, as well as for education and conservation applications. [ABSTRACT FROM AUTHOR]