Cabomba caroliniana in Belgium
Cabomba caroliniana (Cabombaceae: EPPO List of Invasive Alien Plants) is an aquatic submerged ground rooted species native to Argentina and North America. In the EPPO region the species is established in Austria, France, Germany, Hungary, the Netherlands and the United Kingdom (England). The species is invasive in the Netherlands, Australia, Canada, Japan and parts of the USA. In the EU, the species is listed as a species of Union concern (Regulation (EU) 1143/2014). In Belgium, the species was first reported in 1998 and again in 2013 from hydrologically isolated sites (EPPO RS 2017/069). In June 2017, two small viable fragments of C. caroliniana were found floating in the canal Dessel-Turnhout-Schoten near Sint-Lenaarts (province of Antwerp) and in August 2017, several fresh stem fragments were also observed in the canal Zuid-Willemsvaart near Neeroeteren (province of Limburg). A subsequent survey identified a single site along the canal Zuid-Willemsvaart where plants were rooted over an area of 60 m2 and further viable fragments were found over a 25 km stretch of the canal between Neerharen and Bree. The authors suggest that the eradication of C. caroliniana seems unlikely as the species has entered and spread in waterways of considerable size and eradication methods which can be effective and are commonly used for invasive macrophytes are not suitable for large navigable waterbodies. However, surveys are needed in areas adjacent to the canal to determine the extent of further spread and management options will need to be considered to mitigate spread and impacts.
Sources
Scheers K, Denys L, Jacobs I, Packet J, Smeekens V, Adriaens T (2019) Cabomba caroliniana Gray (Cabombaceae) invades major waterways in Belgium. Knowledge and Management of Aquatic Ecosystems 420, 22.