On the phytosociological affiliations of an invasive species Senecio inaequidens in Berlin

During the years 1996–2001 phytosociological relevés were made of stands containing Senecio inaequidens in the city of Berlin and its surrounding. Data on the structure of the stands were recorded, life form spectra and ecological indicator values were calculated. This species, previously not known in the region before 1993, was found in 9 different phytosociological units (allliances). Growth parameters of S. inaequidens differed widely between these units and were positively correlated with cover and height of the surrounding vegetation. The conclusion drawn was that this species is one of the driving forces in the development from annual to perennial vegetation and has a role similar to that of other dominant species. From the indicator values of the stands surrounding S. inaequidens the following Ellenberg indicator values for the species were derived: Light L 8, temperature T 6, continentality K 4, moisture F 4, soil reaction R 7, nitrogen N 0 (= vague), and hemeroby values H α- and β- euhemerobic. Comparisons with data in literature from W and NW Germany show a broader sociological and ecological amplitude of S. inaequidens in this area, which was colonized by this species in the 1970s. The geographical expansion of this species is not yet finished, and further colonization within its area of distribution is likely to occur in plant communities with low degrees of hemeroby and growing in moister habitats.