Ana Novoa 1 , 2 , 3 , * , Giuseppe Brundu 4 , Michael D. Day 5 , Vicente Deltoro 6 , Franz Essl 1 , 7 , Llewellyn C. Foxcroft 1 , 8 , Guillaume Fried 9 , Haylee Kaplan 2 , Sabrina Kumschick 1 , 2 , Sandy Lloyd 10 , Elizabete Marchante 11 , Hélia Marchante 11 , 12 , Iain D. Paterson 13 , Petr Pyšek 1 , 3 , 14 , David M. Richardson 1 , Arne Witt 15 , Helmuth G. Zimmermann 16 , John R. U. Wilson 1 , 2
16 October 2019
The family Cactaceae Juss. contains some of the most widespread and damaging invasive alien plant species in the world, with Australia (39 species), South Africa (35) and Spain (24) being the main hotspots of invasion. The Global Cactus Working Group (IOBC GCWG) was launched in 2015 to improve international collaboration and identify key actions that can be taken to limit the impacts caused by cactus invasions worldwide. Based on the results of an on-line survey, information collated from a review of the scientific and grey literature, expertise of the authors, and because invasiveness appears to vary predictably across the family, we (the IOBC GCWG): (1) recommend that invasive and potentially invasive cacti are regulated, and to assist with this, propose five risk categories; (2) recommend that cactus invasions are treated physically or chemically before they become widespread; (3) advocate the use of biological control to manage widespread invasive species; and (4) encourage the development of public awareness and engagement initiatives to integrate all available knowledge and perspectives in the development and implementation of management actions, and address conflicts of interest, especially with the agricultural and ornamental sectors. Implementing these recommendations will require global co-operation. The IOBC GCWG aims to assist with this process through the dissemination of information and experience.