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This report presents the European Weed Vegetation Database, a new database of vegetation plots documenting short-lived vegetation of arable and ruderal habitats from Europe and Macaronesia. The database comprises the phytosociological classes Papaveretea rhoeadis, Sisymbrietea, Chenopodietea and Digitario sanguinalis-Eragrostietea minoris. It is a gap-focused database containing mainly plots of this vegetation from the areas not yet represented in the European Vegetation Archive (EVA), to facilitate its accessibility for researchers to answer various questions. As of the end of 2018, it contained 24,734 plots, predominantly from Southern Europe. The data can be used for phytosociological studies, various kinds of interdisciplinary research as well as for studies for agronomy, nature management and biodiversity conservation. Syntaxonomic reference: Mucina et al. (2016) Abbreviations: EVA = European Vegetation Archive; GIVD = Global Index of Vegetation-Plot Databases.

A data set of 2,730 phytosociological relevés was used for a comparison of the basic chorological characteristics of the main vegetation types of weed vegetation in the Czech Republic. All relevés were classified by the Cocktail method into the alliances: Caucalidion, Scleranthion annui, Veronico-Euphorbion, Oxalidion fontanae, Spergulo-Erodion and Arnoseridion minimae. The proportions of native species, archaeophytes and neophytes, as well as the proportion of species with particular distribution range types were calculated for each relevé. The weed vegetation in the data set contained 560 species: 38.3% of them were native, 56.2% were archaeophytes and 5.5% were neophytes. The highest proportion of natives was found for the weed vegetation of poor sandy soils (alliance Arnoseridion minimae) and of humid areas (alliance Oxalidion fontanae). The highest proportion of archaeophytes was found in the thermophilous weed vegetation of Caucalidion and Spergulo-Erodion alliances, and the highest proportion of neophytes in Spergulo-Erodion alliance. Czech weed vegetation is predominantly composed of species of Euroasian temperate range type. These species prevail in weed vegetation of alliances Scleranthion annui and Oxalidion fontanae. Macaronesian-Mediterranean range types and Oriental-Turcestani-Mediterranean range types make up 25–38% of all weed species growing in the Czech Republic. These Mediterranean species dominate in the weed vegetation of alliances Caucalidion and Arnoseridion minimae, followed by alliances Veronico-Euphorbion and Spergulo-Erodion. The proportion of central European species is similar (about 10% of species) in all the compared vegetation types except Spergulo-Erodion, where these species are rarer (only 5%). Other chorological types are scarcely present in the weed vegetation of the Czech Republic.

The vegetation dynamics on the exposed bottoms of fishponds and storage ponds in the Ceskobudejovická basin (South Bohemia, Czech Republic) were studied. In 2001 ? 2002, a total of 42 permanent plots in 19 storage ponds and 7 plots in 2 nursery fishponds were established. Phytosociological relevés were recorded using the Braun-Blanquet method and stored in the Czech National Phytosociological Database in TURBO(VEG). 445 relevés from autumn 2001 and the vegetation period of 2002 were analysed using the DCA and CCA methods from the package CANOCO, STATISTICA software and JUICE 6.1 software. Species lists exported from TURBO(VEG) served as a general description of species richness. This study attempts to explain the relationship of vegetation cover and floristic spectrum on the one hand to abiotic factors and management on the other hand. The CCA analysis detected moisture and the week in which the data were recorded to be the most important variables. These factors influence the basic vegetation structure and species composition; however, they explain only 2.5% of the variability. Both factors are partly given by the type of summer drying of the pond, i.e., by the management. According to the type of summer drying and vegetation phase we distinguished spring ponds (the storage ponds and nursery fishponds) and summer ponds. The nursery fishponds are only shortly dried in April?June. Therefore, annual species with extremely short live cycles occur there, e.g., Coleanthus subtilis. Thermophilous species, germinating in May and June, and plants with longer life cycles are eliminated. The spring storage ponds are dried from December or early spring throughout the whole vegetation period. They are characterized by many perennial species, e.g., Juncus articulatus and Equisetum palustre. In the summer storage ponds, dry mostly for 2?4 months in summer and early autumn, thermophilous annual species, such as Lindernia dubia, are found.Besides summer drying, other management practices are used in the storage ponds, e.g., herbicide spraying, mowing, liming, etc. These practices can exclude some species from the total species spectrum and can have positive influence on the development of other species. For example herbicides and mowing reduce total cover and competition from some perennial species, which supports the survival of annuals in the vegetation. The diversity of the storage ponds' environments was considerably higher than that of the fishponds, and this was reflected in the species richness. In 17 relevés from fishponds, a total of 24 plant species were found; in 17 comparable relevés from storage ponds, 64 species were recorded.