First report of Lygodium microphyllum in Reunion Island
Lygodium microphyllum (Lygodiaceae) is a climbing fern with underground rhizomes originating from tropical and subtropical Africa, Asia, Polynesia and Australia. In the Mascarene Islands, the species was so far only recorded in Mauritius Island where it forms dense populations. The species is also considered invasive in Florida (US).
This fern was found for the first time in La Plaine des Palmistes in Reunion Island at an altitude of 880 m in a marshy prairie of Juncus effusus (Juncaceae), which represents a heritage site. One single plant was covering 1 m² and was found by a local botanist and expert on ferns.
L. microphyllum reproduces both vegetatively through rhizomes, and sexually through spores, which are spread by the wind and to a lesser extent by water over long distances. The species can have a high impact on the environment by covering all strata of a habitat. The rhizome forms dense and thick mats that can block decomposition and regeneration of the soil. The species may also have impact on sylviculture, pastoralism and cultivations in forests such as vanilla. The species is listed as an invasive alien plant for which introduction and spread should be prohibited in Reunion Island according to the prefectural decree n°2011-01479. As humid and subhumid heritage habitats are at risk from L. microphyllum in Reunion Island, an eradication programme will be undertaken consisting in digging out the plant and its rhizomes and burning them, followed by chemical control. Such eradication will be conducted by the National Park.
Sources
Tamon JM, Fontaine C, Picot F (2012) Une nouvelle fougère exotique, potentiellement très envahissante et impactante, Lygodium microphyllum (Cav.) R. Br. a été découverte sur l’île de La Réunion. 4 pp.
Préfet de la Région Réunion, Arrêté Préfectoral n°2011 – 001479 Fixant les conditions phytosanitaires requises pour l’introduction sur le territoire de l’île de la Réunion de végétaux, produits végétaux et autres objets. http://daaf974.agriculture.gouv.fr/IMG/pdf/AP2011-001479conditions_import_vegetaux_cle84661f.pdf