A new record of Cabomba caroliniana in the French Pyrenees
The ‘Conservatoire Botanique National des Pyrénées et de Midi-Pyrénées’ has performed a floristic inventory on the river banks of the Canal du Midi, with the financial support of regional institutions. A new aquatic plant has been recorded between Ramonville-Saint-Agne and Toulouse which was identified a few months after its collection as Cabomba caroliniana (Cabombaceae, EPPO List of IAP). This identification was helped by the consultation of aquariophilist websites. The species is expected to have been introduced into the Canal du Midi through aquaria dumping.
In July 2009, C. caroliniana was found in 2 places:
- In the Pont des Demoiselles in Toulouse, where boats are moored, C. caroliana was found in sunny places with calm and deep waters. Green algae were observed growing through stands of C. caroliniana.
- C. caroliniana also formed large populations 6 km south of this first site, in a basin in Ramonville-Saint-Agne (at the location “Combes”). This basin is used for boats repairs. Fragments of the species were also found floating between the 2 sites.
C. caroliniana could survive during winter through small rooted fragments or fragments in the mud, and multiply and spread in summer when conditions are suitable.
This species should be monitored in the Canal du Midi, and is added to the list of aquatic alien plants occurring in the Pyrénées and introduced through aquaria, with Egeria densa (Hydrocharitaceae, EPPO List of IAP), Ceratophyllum demersum (Ceratophyllaceae) and Myriophyllum spicatum (Haloragaceae).
Enjalbal M (2009) Cabomba caroliniana A. Gray : de l’aquarium au Canal du Midi. Isatis 31(9) 28-32. http://www.isatis31.botagora.fr/fr/revue.aspx