Stellenbosch University Botanical Garden, South Africa

Common name: watervaring, Kariba weed, giant salvinia

Family: Salviniaceae (Salvinia)

Distribution: Brazil

Habitat: Various aquatic habitats

IUCN Red list: Not evaluated

National red list: Not Evaluated

Black list: Listed NEMBA Category 1 Invasive - Must be destroyed/removed by law.

Life form: Aquatic

Comments: This free-floating fern was first discovered outside its native range in Lake Kariba in 1959 and has subsequently spread to many tropical and subtropical countries, where it colonises disturbed habitats. It forms dense mats which decrease water quality and aquatic biodiversity. In SA a weevil, Cyrtobagous salviniae, has been successfully used to manage this species.