Prospects for extirpating small populations of the wetland invader Melaleuca quinquenervia from South Africa: a case study from the Western Cape region

Abstract

The broad-leaved paper bark tree Melaleuca quinquenervia is a major invader in the wetlands of the Florida Everglades, USA. In South Africa, this introduced species is known from eight locality records and is naturalising at two of these sites. The potential for its spread to other wetlands and estuaries is of concern. The naturalising population near Wolseley, Western Cape, was discovered in May 2009 and is confined to a mountain seep. Given that the Wolseley infestation is restricted to only 0.28 ha, extirpation seemed feasible, and a monitoring system was devised to record population characteristics and response to control measures. Suppression of seedling recruitment and reduction in the number of coppicing stems over a six-year period (2009-2014) suggest that it will be possible to extirpate M. quinquenervia from the Wolseley site. Factors that hinder or favour its successful extirpation are presented and the implications of this study for the management of other small populations of this species in South Africa are discussed.