Coreopsis grandiflora in Switzerland
Coreopsis grandiflora (Asteraceae) is a perennial species native to North America and it is utilised as an ornamental species in the EPPO region. In Europe, it is established in Belgium and Germany, and it is reported as an invasive alien plant in Australia and China. In Switzerland, it has previously been reported in the wild, but these reports were of individuals, possibly escaped from gardens. A recent extensive assessment of C. grandiflora in Southern Switzerland highlights that the species can be regarded as a species with potentially invasive behaviour. It has been reported from Southern Switzerland since 2019 from several different habitats including meadows, ruderal habitats, riverbanks and other riparian habitats. It has been reported from environmentally important habitats in floodplains along the Maggia River in the Canton Ticino, Switzerland. In areas where it occurs, dense stands of the species can produce a high number of seeds which are spread naturally over short distances. Human mediated spread can act to spread propagules over longer distances. Further research is required to assess any negative impacts on habitats and the species within. To prevent further spread, management measures should be implemented especially in vulnerable habitats.
Sources
Marazzi B, Mangili S, Gygax A, Jousson A (2022) Biology and spread of the new alien species Coreopsis grandiflora (Asteraceae) in southern Switzerland. Bollettino della Società ticinese di scienze naturali 110, 57-70.