Alien species in South Africa’s national parks
Invasive alien species (IAS) are one of the major threats to biodiversity in protected areas and pose a significant management challenge (see Allen, Brown & Stohlgren 2009; Pyšek, Jarošík & Kučera 2002). One of the first steps towards managing IAS in protected areas is establishing which alien species are present, followed by ongoing surveillance and prevention efforts to combat new introductions (Foxcroft et al. 2009). Information on the identity and traits of alien species is needed for conducting risk assessments and prioritising species for control, as well as for monitoring management effectiveness in preventing new introductions (McGeoch et al. 2010). It also provides a first step towards monitoring the extent of occurrence of alien species in national parks.