Browsing by Author "Zimmermann, Helmuth G."

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    Global actions for managing cactus invasions
    (MDPI, 2019-10-16) Novoa, Ana; Brundu, Giuseppe; Day, Michael D.; Deltoro, Vicente; Essl, Franz; Foxcroft, Llewellyn C.; Fried, Guillaume; Kaplan, Haylee; Kumschick, Sabrina; Lloyd, Sandy; Marchante, Elizabete; Marchante, Helia; Paterson, Iain D.; Pysek, Petr; Richardson, David M.; Witt, Arne; Zimmermann, Helmuth G.; Wilson, John R. U.
    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.
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    A proposed national strategic framework for the management of Cactaceae in South Africa
    (AOSIS Publishing, 2017) Kaplan, Haylee; Wilson, John R.U.; Klein, Hildegard; Henderson, Lesley; Zimmermann, Helmuth G.; Manyama, Phetole; Ivey, Philip; Richardson, David M.; Novoa, Ana
    Background: South Africa has a long history of managing biological invasions. The rapid increase in the scale and complexity of problems associated with invasions calls for new, more strategic management approaches. This paper explores strategic management approaches for cactus invasions in South Africa. Cacti (Cactaceae) have had a long history of socio-economic benefits, considerable negative environmental and socio-economic impacts, and a wide range of management interventions in South Africa. Objectives: To guide the future management of cactus invasions, a national strategic framework was developed by the South African Cactus Working Group. The overarching aim of this framework is to reduce the negative impacts of cacti to a point where their benefits significantly outweigh the losses. Method: Four strategic objectives were proposed: (1) all invasive and potentially invasive cactus species should be prevented from entering the country, (2) new incursions of cactus species must be rapidly detected and eradicated, (3) the impacts of invasive cacti must be reduced and contained and (4) socio-economically useful cacti (both invasive and non-invasive species) must be utilised sustainably to minimise the risk of further negative impacts. Results: There are currently 35 listed invasive cactus species in the country; 10 species are targeted for eradication and 12 are under partial or complete biological control. We discuss approaches for the management of cactus species, their introduction and spread pathways and spatial prioritisation of control efforts. Conclusion: A thorough understanding of context-specific invasion processes and stakeholder support is needed when implementing strategies for a group of invasive species.