Is phenotypic plasticity an explanation for the invasiveness of goldenrods (Solidago and Euthamia) in Europe?
High phenotypic plasticity contributes to invasiveness of alien species. Goldenrods of American origin (Solidago canadensis, S. gigantea and Euthamia graminifolia) have successfully invaded Europe, and this success can be related to their high phenotypic plasticity. The aim of our study was to test the hypothesis of higher phenotypic plasticity of invasive goldenrods by comparing them with native taxa: closely related Solidago virgaurea and similar ecologically, invasive in other regions Tanacetum vulgare. The species studied were grown in a common garden on three different substrates with different fertilizers. After 3 years, the height and number of ramets, biomass production and allocation, phenology and nitrate reductase activity (NRA) were measured. The highest level of phenotypic plasticity was exhibited by the competitively weak native species S. virgaurea. The invasive species produced relatively high biomass and exhibited a moderate level of phenotypic plasticity. Variability in the studied traits did not always correlate with differences in substrates. The invasion success of non-native goldenrods is not caused by their having a higher phenotypic plasticity than native species. Rather, the non-natives should be considered as "Jack of all traits, and master of some".