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Der Global Index of Vegetation-Plot Databases (GIVD) ist eine Metadatenbank von Vegetations - datenbanken weltweit, die im Jahr 2010 von einem internationalen Leitungsgremium ins Leben gerufen wurde und auf einem Server in Greifswald beheimatet ist. Ziel von GIVD ist es, einen besseren Überblick über die zunehmende Zahl von Vegetationsdatenbanken zu geben und ihren Inhalt für übergreifende vegetationsökologische Analysen zu erschließen. Im vorliegenden Beitrag analysieren wir, welche Daten aus Mitteleuropa (incl. Benelux-Länder) in GIVD derzeit registriert sind. Am 20. März 2011 stammten 1,35 Millionen der insgesamt registrierten 2,45 Millionen Vegetationsaufnahmen aus den 12 betrachteten Ländern. Mit über 600.000 digital verfügbaren Vegetationsaufnahmen entsprechend einer Dichte von 18 km–2 sind die Niederlande weltweit führend.
We aimed to assess the utility of the Global Compendium of Weeds (GCW) as an indicator of plant invasiveness, by relating it to invasiveness at smaller scales. We correlated two global measures of invasiveness for alien plant species taken from the GCW (the total number of references for each species and the number of continental areas they are reported from), against distribution data from 18 regions (countries and continents). To investigate relationships between correlation strength and region size and spatial resolution (size of distribution units), we conducted meta-analyses. Finally, invasiveness measures were correlated against the number of habitats occupied by alien plant species and their median abundance in those habitats, in fine-scale vegetation plots in the Czech Republic and the state of Montana (USA). The majority of Spearman’s rho coefficients between GCW-derived invasiveness and regional distributions were less than 0.4. Correlation strength was positively related to region size and resolution. Correlations were weaker when the number of habitats occupied by a species, and species abundances within occupied habitats, were considered. We suggest that the use of the GCW as an invasiveness measure is most appropriate for hypotheses posed at coarse, large scales. An exhaustive synthesis of existing regional distributions should provide a more accurate index of the global invasiveness of species.