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Accepted manuscript

Regulatory options for cultivars and hybrids of invasive plant species – the South African experience

Published online by Cambridge University Press:  29 October 2024

Duran Chetty*
Affiliation:
Horticultural Sciences Department, Cape Peninsula University of Technology, Bellville Campus South African National Biodiversity Institute, Kirstenbosch Research Centre, Cape Town, South Africa
Arunava Datta
Affiliation:
South African National Biodiversity Institute, Kirstenbosch Research Centre, Cape Town, South Africa Department of Botany, Raja Narendralal Khan Women’s College, Gope Palace, P.O: Vidyasagar University, Dist: Paschim Medinipur, Pin: 721102 Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, South Africa
Sabrina Kumschick
Affiliation:
South African National Biodiversity Institute, Kirstenbosch Research Centre, Cape Town, South Africa Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, South Africa
John R. U. Wilson
Affiliation:
South African National Biodiversity Institute, Kirstenbosch Research Centre, Cape Town, South Africa Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, South Africa
Felix Nchu
Affiliation:
Horticultural Sciences Department, Cape Peninsula University of Technology, Bellville Campus
Sjirk Geerts
Affiliation:
Department of Conservation and Marine Sciences, Cape Peninsula University of Technology, P.O. Box 652, Cape Town 8000, South Africa
*
Corresponding author: email: [email protected]
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Abstract

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Invasive plant taxa are generally regulated at the species level, without considering infra- or inter-specific variation. However, cultivars or hybrids can be of a lower level of risk, e.g., due to sterility. We evaluate six general approaches to regulating cultivars and hybrids -1) “Globally guilty by association”; 2) “Nationally guilty by association”; 3) “Guilty until proven innocent”; 4) “Negotiated guilt”; 5) “Claimed to be innocent”; and 6) “Innocent until proven guilty”. We discuss these approaches in the context of South Africa (which has a typified “Negotiated guilt” approach). Following negotiations since 2001 between the South African horticultural industry/green industry and legislators, an unofficial consensus list of “presumed sterile” cultivars and hybrids was produced in 2014 containing 187 entities from 34 taxa. In 2020 this was reduced to 157 entities from 16 taxa. But the evidence supporting the original lists and the subsequent revisions were not published. To address this issue, we developed a generic pro-forma for reporting sterility based on observations and/or experiments on: flowering, fruiting, pollen, and seeds; the potential for vegetation propagation; and the potential for genetic changes (including hybridisation and reversion to fertility). We recommend that such information should be incorporated into risk analyses conducted specifically for infra- and inter- specific entities, and only if the risk of a harmful invasion is demonstrated to be acceptably low or can be easily mitigated should such entities be exempted from regulation. This will be time-consuming, but by setting out the evidence clearly, the approach is transparent and provides a clear route for stakeholders to seek exemptions for entities of importance. In summary, although we suspect the simplicity of the “Negotiated guilt” approach is desirable to many stakeholders; in general, and specifically for South Africa, we recommend a shift towards the “Guilty until proven innocent” approach.

Type
Research Article
Copyright
© Weed Science Society of America, 2024