Why alien B. frondosa displaces native Bidens species in Central Europe?
Helena Gruberova Department of Botany, Faculty of Biological Sciences, University of South Bohemia, Branisovska 31, Ceske Budejovice, CZ -370 05, Czech Republic B. frondosa is an annual species of the Asteraceae family, which original occurrence is in the North America. It occurs from north Canada to the south of the U.S.A., where it grows mainly on riversides, at the shore of water reservoirs, in pastures, along roads, in gardens, in fields and various waste places, all with higher soil moisture. The genus Bidens has three native representatives in Central Europe, namely B. radiata, B. tripartita and B. cernua. The alien B. frondosa seems to be more successful in competition with the native species. Two species B. frondosa and B. tripartita were experimentally grown in pots (40×30×30cm) in mixture and separately in three different densities (14, 60 and 300 individuals per pot) and the height of 7 individuals from each pot were measured at the time of ripening. B. tripartita was more s
