Gymnocoronis spilanthoides a new naturalized invasive aquatic plant in Southern Europe
Gymnocoronis spilanthoides (Asteraceae: EPPO Observation List) is an aquatic freshwater or marsh growing emergent perennial species which has been traded worldwide as an aquatic ornamental plant. Native to South America, G. spilanthoides is an invasive alien species in Australia, New Zealand, Japan and China and Taiwan. Within the EPPO region, G. spilanthoides has been recorded in Hungary in canals connected to thermally influenced waters. Where the species invades and establishes, it can block drainage channels and degrade natural wetlands by outcompeting native species. An extensive population of G. spilanthoides was found in an irrigation canal in Zerbolò (Lombardia, Italy) in July 2015 and further surveys in the local area revealed an additional population 1.9 km from the first. The monospecific mats occupy stretches up to 519 m in length covering the whole width of the canal. At the first site, a large stand was found growing within a rice field in proximity to the canal. Potentially, dispersal of vegetative parts may have been enhanced by mechanical management of the rice fields. Interestingly, in October 2016, EPPO will conduct a pest risk analysis on G. spilanthoides within the LIFE funded project ‘Mitigating the threat of invasive alien plants in the EU through pest risk analysis to support the EU Regulation 1143/2014’.
Ardenghi NMG, Barcheri G, Ballerini C, Cauzzi P, Guzzon F (2016) Gymnocoronis spilanthoides (Asteraceae, Eupatorieae), a new naturalized and potentially invasive aquatic alien in S Europe. Willdenowia, DOI: 10.3372/wi.46.46208