Carduus nutans in South Africa: distribution, threats, and opportunities for management

Carduus nutans in South Africa: distribution, threats, and opportunities for management
Kanyisa Jama and Thifhelimbilu Rambuwane
Invasive Species Programme, South African National Biodiversity Institute, 4a Princess Road office Park Vincent, East London 5200

Carduus nutans is native to Europe and Asia, but is a serious invader in many parts of its introduced range in North America, South America, Australia, and New Zealand. For example, in the United States the species is declared as a noxious weed in 22 states.   It is unclear how the species was introduced into South Africa.  .  However the first SAPIA records dates back to 1925, and it is now widespread in areas like Grahamstown, Cradock, Kenton-on-Sea, Paterson and Addo, yet it has not been categorized and listed as an invasive plant under CARA or NEM:BA.   Here we propose a research project to assess the current distribution and risks posed by Carduus nutans to South Africa. The results of the risk assessment will give us an indication of whether the species is a threat to South Africa, what management options are available, and whether the species should be listed as an invasive species requiring control.