ORIGINAL RESEARCH

 

A South African perspective on the 2023 IPBES Thematic Assessment Report on Invasive Alien Species and their control

 

 

J.R.U. Wilson^{I, II}; K.T. Faulkner^{I, III}; L. Fernández Winzer^{I, II}; E.J. McCulloch-Jones^{I, II, III}; B.W. van Wilgen^II; R. Blanchard^{II, IV}; C. Carbutt^{V, VI}; M.S. Dechoum^VII; L.C. Foxcroft^{II, VIII}; M. Greve^IX; C. Hui^{X, XI, XII}; P Ivey^XIII; B. Kgope^XIV; S. Kumschick^{I, II}; P.C. le Roux^IX; T.S. Masehela^XIV; J. Measey^{II, XV, †}; S. Miza^I; T. Mogapi^XIV; F. Mpikanisi^XIV; L. Mulaudzi^XVI; K. Nelukalo^XVII; L. Nnzeru^XVII; M.M. Nsikani^{I, XVIII}; Z. Pattison^XIX; S.J. Rahlao^{XX, XXI}; D.M. Richardson^II; T.B. Robinson^II; R.T. Shackleton^{II, XXII}; F. Tererai^XXIII; N. Tshidada^XXIII; P.P. Tshikhudo^XXIV; I. Tshivhandekano^XXV; K. Wanjau^XXVI; S.R. Ziller^XXVII; T.A. Zengeya^{I, XXVIII}

^IKirstenbosch Research Centre, South African National Biodiversity Institute, Cape Town, South Africa
^IICentre for Invasion Biology, Department of Botany & Zoology, Stellenbosch University, Stellenbosch, South Africa
^IIIDepartment of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
^IVFynbos Node, South African Environmental Observation Network, Observatory 7925, South Africa
^VScientific Services, Ezemvelo KwaZulu-Natal Wildlife, Cascades 3202, South Africa
^VISchool of Life Sciences, University of KwaZulu-Natal, Scottsville 3209, South Africa
^VIIDepartamento de Ecologia e Zoologia, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil
^VIIIScientific Services, South African National Parks, Skukuza, South Africa
^IXDepartment of Plant and Soil Sciences, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
^XCentre for Invasion Biology, Department of Mathematical Sciences, Stellenbosch University, Stellenbosch 7602, South Africa
^XIBiodiversity Informatics Unit, African Institute for Mathematical Sciences, Cape Town 7945, South Africa
^XIINational Institute for Theoretical and Computational Sciences (NITheCS), Stellenbosch 7602, South Africa
^XIIICentre for Biological Control, Department of Zoology & Entomology, Rhodes University, Makhanda, South Africa
^XIVBiodiversity Risk Management, Biosafety and Alien Invasive Species, Department of Forestry, Fisheries and the Environment, Environment House, 473 Steve Biko Road, Pretoria, South Africa
^XVCentre for Invasion Biology, Institute for Biodiversity, Yunnan University, Kunming, China
^XVIAgricultural Research Council-GC, 114 Chris Hani Drive, Potchefstroom 2531, South Africa
^XVIIBiodiversity Risk Management, Issuing Authority, Department of Forestry, Fisheries and Environment, 14 Loop Street, Cape Town, South Africa
^XVIIICentre for Invasion Biology, Department of Conservation Ecology and Entomology, Stellenbosch University, Stellenbosch, South Africa
^XIXFaculty of Natural Sciences, Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, Scotland
^XXOceanographic Research Institute, Durban, South Africa
^XXISchool of Life Sciences, University of KwaZulu-Natal, Durban, South Africa
^XXIISwiss Federal Institute for Forest, Snow and Landscape Research, WSL, Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
^XXIIIPretoria National Botanical Gardens, South African National Biodiversity Institute, Pretoria, South Africa
^XXIVPest Risk Analysis Division, Directorate Plant Health, Department of Agriculture, South Africa
^XXVBiosecurity Compliance, Oceans, Coasts and Biosecurity Compliance, Department of Forestry, Fisheries and the Environment, Environment House, 473 Steve Biko Road, Pretoria, South Africa
^XXVIBorder Management Authority, South Africa
^XXVIIInstituto Hórus de Desenvolvimento e Conservação Ambiental, Florianópolis, Santa Catarina, Brazil
^XXVIIICentre for Invasion Biology, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa

Correspondence

 

 

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ABSTRACT

BACKGROUND: Biological invasions are a major threat to biodiversity and sustainable development. A global assessment of biological invasions released in 2023 by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), concluded that while invasions '...cause dramatic and, in some cases, irreversible changes...' they can be '...overcome through a context-specific integrated governance approach'
AIM: Here we evaluate insights from the IPBES assessment in the context of South Africa and explore how these insights could inform the development of a national policy and strategy to address biological invasions
RESULTS: Trends and status of biological invasions in South Africa are similar to those seen globally, but there are some distinct local nuances. South Africa has: 1) a long history of invasions with negative impacts caused especially by invasive trees and freshwater fishes, whilst invasive marine invertebrates have transformed large parts of the coastline; 2) a long history of control (biological control was first implemented in 1913) with large-scale, state-run invasive species management programmes currently in place; 3) a comprehensive regulatory system (e.g., there is provision for beneficial invasive species to be used under permits); 4) relatively high levels of awareness and engagement (at least among some stakeholder groups); and 5) a well-connected community of practice
DISCUSSION: Efforts to limit introductions (intentional or unintentional) are difficult given South Africa's extensive and porous borders and the pressing need to increase trade and travel. Regulatory and implementation efforts aimed at prevention are improving, with the newly established Border Management Authority aiming to integrate biosecurity interventions at ports of entry. Such integrated governance is, we argue, needed more broadly if affected sectors, society groups and stakeholders are to be effectively included in decision-making and management. A more systematic flow of information from observation to action is essential, as is better feedback between research, policy and implementation at all scales. Biological invasions will continue to pose threats, but many of these can be effectively mitigated through focussed interventions. Co-ordinating such interventions in the context of other cross-cutting global change challenges and initiatives is a cost-effective way of protecting and improving livelihoods, human health, quality of life and biodiversity

Keywords: biological invasions, invasion science, Science-policy interface, the Kunming-Montreal Global Biodiversity Framework (KM-GBF), IPBES IAS Assessment

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Introduction

Biological invasions are a global issue with negative impacts on biodiversity and human well-being (Pysek et al. 2020; Roy et al. 2024; WTO 1998). The introduction and spread of invasive species are facilitated directly and indirectly by different drivers such as the increasing movement of goods and people around the world (Hulme 2021), land- and sea-use change, and climate change (Bellard et al. 2016). Rates of introduction are projected to continue to increase (Seebens et al. 2021). Because biological invasions transcend regional and national boundaries, international collaboration, including the co-ordination of responses and the sharing of insights and expertise, is essential for effective mitigation and management (Faulkner et al. 2020b; IPBES 2023a). Nonetheless, the negative impacts of biological invasions are felt and addressed primarily at local levels, whilst control and regulation efforts are typically decided upon by national jurisdictions (García-de-Lomas & Vilà 2015). Biological invasions are also facilitated by, and impact on, a wide range of sectors (IPBES 2023a), including agriculture (Paini et al. 2016) and human health (Mazza et al. 2014), making co-ordination amongst stakeholders essential. Despite these complexities, managing biological invasions has been shown to be amongst the most cost-effective conservation measures available (Lang-hammer et al. 2024; Roy et al. 2024).

Global policy is increasingly addressing the challenge of biodiversity loss and associated changes in ecosystem services. The fifteenth meeting of the Conference of the Parties to the Convention on Biological Diversity (CBD) adopted the Kunming-Montreal Global Biodiversity Framework (KM-GBF) in December 2022. The framework resulted from a four-year consultative and negotiation process and includes 23 action-oriented targets for 2030 and four goals for 2050. Target six (6) focuses on biological invasions and calls on parties to the CBD to:

'Eliminate, minimize, reduce and or mitigate the impacts of invasive alien species on biodiversity and ecosystem services by identifying and managing pathways of the introduction of alien species, preventing the introduction and establishment of priority invasive alien species, reducing the rates of introduction and establishment of other known or potential invasive alien species by at least 50 per cent, by 2030, eradicating or controlling invasive alien species especially in priority sites, such as islands.'

(CBD 2023)

In parallel with activities of the CBD, member states of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) requested a thematic assessment report on biological invasions in 2014. The Thematic Assessment Report on Invasive Alien Species and their Control (hereafter the IPBES IAS Assessment) officially started in 2019 with co-chairs, coordinating lead authors, lead authors, fellows, review editors and contributing authors (Schwindt et al. 2024) ensuring inclusive and diverse views and contributions from across the world, including Indigenous Peoples and local communities (Nuñez et al. 2024). The IPBES guidelines for conducting such an assessment highlight the process as an iterative and collective critical evaluation of the state of knowledge by experts across several chapters, agreed upon in the scoping report (IPBES 2018b). The main findings of each chapter are then summarised in policy relevant key messages, incorporating less technical language, with links to the relevant evidence in the chapters. The Summary for Policymakers (SPM) is then reviewed and negotiated by member states before its approval (IPBES 2023a). The IPBES IAS Assessment was accepted and its summary for policy-makers approved during the 2023 IPBES Plenary in Bonn, Germany. The IPBES IAS Assessment was released on 4 September 2023 (IPBES 2023a).

South Africa made a significant contribution to the IPBES IAS Assessment. The 285 experts listed in the assessment came from 59 countries (Schwindt et al. 2024, Supplementary Table S1), 25 of which (close to 10%) included South Africa as one of their affiliations. Only the UK (39), the USA (35), and Australia (28) had more affiliates (Germany also had 25 listed affiliates). South Africa's significant contribution is not surprising - the country has a long history of being affected by and managing biological invasions and is a global leader in research and capacity building on biological invasions (Van Wilgen et al. 2020a).

South Africa also pioneered the production of national level reports on the status of biological invasions (Wilson et al. 2017). As mandated under the National Environmental Management: Biodiversity Act (Act no. 10 of 2004) and its Alien and Invasive Species Regulations [the NEM:BA A&IS Regulations first promulgated in 2014, and most recently updated in 2020 (Wilson & Kumschick 2024)], triennial reports have been produced, titled The Status of Biological Invasions and their Management in South Africa in [2017, 2019 and 2022] (Van Wilgen & Wilson 2018; Zengeya & Wilson 2020; 2023), hereafter 'the South African status report'.

Both the IPBES IAS Assessment and the South African status reports collate information from a broad range of sources and are intended to be policy relevant but not policy prescriptive. Both reports underwent two rounds of open public external review, although the IPBES IAS Assessment underwent an additional round of government review and a formal process for governmental approval at the IPBES Plenary. The major differences between the reports are in terms of structure and scope. The South African status reports are framed around a set of 20 indicators that address biological invasions from the perspective of pathways, species, sites and interventions (McGeoch et al. 2016; Wilson et al. 2018), with a concluding chapter on gaps (both knowledge gaps and gaps in what we are doing to address the problem). The IPBES IAS Assessment had chapters on status and trends, drivers, impacts, management and future options, with knowledge gaps identified within each chapter. The IPBES IAS Assessment does not report on indicators per se, nor does it provide recommendations on which indicators to use. In terms of definitions, the IPBES IAS Assessment (while acknowledging the multi-faceted impacts of biological invasions) defined invasive species purely in terms of those taxa which cause negative impacts on biodiversity. This was because the assessment arises from the CBD and the assessment authors were constrained by the IPBES processes and definitions, including a scoping document agreed by IPBES prior to the assessment starting (IPBES 2018a). No such restrictions are placed on the South African status reports; a biogeographic definition of invasions is preferred (Box 1). Finally, the IPBES IAS Assessment was global whereas the South African status reports are national.

In 2023, South Africa adopted a White Paper on 'the Conservation and Sustainable Use of South Africa's Biodiversity' (Department of Forestry, Fisheries and the Environment 2023). The White Paper addresses invasive species through policy objective 1.4: 'Identify and manage harmful, and potentially harmful, invasive alien species, their potential and existing introduction pathways and biological invasions.' This has created a platform for South Africa's policy and regulations on biological invasions to respond to the KM-GBF, and specifically to implement Target 6 of the KM-GBF at a national level. Notably the focus of this White Paper (and the action paper that is being developed to facilitate it) is on the threat to biodiversity. However, South Africa still has a need for a policy and strategy that addresses all aspects of biological invasions, i.e., beyond the threat just to biodiversity. This is a key recommendation of the South African status reports (Zengeya & Wilson 2023). Since 2023, relevant government departments have engaged in developing a National Invasive Species Strategy and Action Plan (NISSAP). Given the launch of the IPBES IAS Assessment and the setting of Target 6 of the KM-GBF, it is an opportune time to reflect on what a policy and national strategy for South Africa should include. This paper aims to assist South Africa to meet its various obligations (international commitments, national imperatives and local needs); and aims to serve as a model for other countries and regions seeking to meet KM-GBF targets. This paper tries to specifically address the following:

• How do statements and proposals in the IPBES IAS Assessment resonate in South Africa?

• Is South Africa addressing the issues raised by the IPBES IAS Assessment?

• What should South Africa do to improve responses to biological invasions (particularly in the context of the proposed national strategy)?

 

Materials and methods

We undertook a qualitative synthesis based on expert review. We argue this approach is appropriate, if only in that it facilitated discussion, and forced us to be clear on our views and to identify assertions that can be resolved based on evidence and data. Insights were gleaned from the South African status reports, published literature and reports, and from the diverse backgrounds and expertise of us as authors. To capture the perspective of those who were directly involved in relevant processes, invitations to contribute were sent to: all those involved as experts in the IPBES IAS Assessment who listed South Africa as an affiliation (Supplementary Table S1); members of the South African delegation to the tenth session of the IPBES Plenary at which the IPBES IAS Assessment was approved; the chapter lead authors of the latest version of the South African status report (Zengeya & Wilson 2023); and the task team responsible for drafting South Africa's national strategy on biological invasions.

Focussing primarily on the Summary for Policymakers (IPBES 2023a) of the IPBES IAS Assessment (IPBES 2023b), we identified four key elements relevant to South Africa:

• The 22 key messages in the Summary for Policymakers (p. 12-17 of the IPBES IAS Assessment's SPM; see Table 2 and Supplementary Table S2 for the results).

• The six identified management objectives, and eleven management actions (Table SPM.1 in the IPBES IAS Assessment; see Supplementary Table S3 for the results).

• The seven strategic actions, four properties of governance systems that support integration, and the twelve options for strengthening governance (Figure SPM.7 and Table SPM.2 in the IPBES IAS Assessment; see Table 3 for the results).

• The synthesis of knowledge and data gaps (Appendix 2 and Table SPMA.1 in the IPBES IAS Assessment; see Supplementary Table S4 for the results).

In each case we evaluated how these elements resonate for South Africa using a semi-quantitative scale developed for this purpose (Table 1A). Each evaluation was also ascribed one of four levels of confidence as per the IPBES guidelines (IPBES 2018b) (Table 1B).

Throughout the process, we identified recommendations for South Africa's draft national strategy. As noted in the most recent South African status report, the issue of biological invasions on mainland South Africa is significantly different from that on South Africa's sub-Antarctic islands (the Prince Edward Islands, cf. Box 2), with different stakeholders involved. Therefore, we decided to evaluate the Prince Edward Islands separately and plan to conduct a similar exercise at a later stage.

A draft outline was circulated to a core group (those directly involved in the South African status report or leading the draft national strategy) for discussion (January-February 2024). This led to the focus on the five key elements of the IPBES IAS Assessment listed above and how they should be scored. From here, all five elements were shared online with a request for input (March-April 2024). Of the 71 people invited, 36 indicated that they wished to be involved further. Sections of the document were also discussed in person as part of a two-day workshop on drafting the national strategy (March 2024). A further round of online commenting was held (April-May 2024), complemented by four online sessions where each of the five key elements were discussed and edited in plenary (each session was ~ 3 hours with between 11 and 24 participants). Based on these discussions and the emerging insights, a draft of the full manuscript was compiled and posted online for comments and input, with specific tasks allocated (May-June 2024). An online session was held to identify the actions needed to fill in gaps. The manuscript was then completed, circulated for comment in sequence (June-August 2024), with a final version made available for approval by authors (August 2024). To provide a comparison and a less directly biased overview, we invited two Brazilian experts on biological invasions and their management and regulation in the Americas (one of whom acted as a review editor for the IPBES IAS Assessment and the other was a contributing author to the IPBES IAS Assessment, both of whom were on sabbatical in South Africa at the time) to review the draft and provide an external perspective (Box 3).

 

Results

The key messages

Most of the 22 key messages of the IPBES IAS Assessment resonated strongly with what we perceive the situation in South Africa to be - 14 were scored as 'completely agree', five as 'largely agree', two were 'somewhat similar', and one was 'different' (Table 2). The differences from the global assessment are that: 1) South Africa has shown significant progress with managing and regulating biological invasions (e.g., Wilson & Kumschick 2024) (cf. key message A5); 2) the available evidence does not suggest that rates of introduction have increased drastically over the past few decades (Faulkner 2023) (cf. key message B2); and 3) there are few examples of successful nationwide eradications to date (Davies et al. 2020b; Wilson et al. 2013) (cf. key message C3). Despite a system in place to regularly report on biological invasions in the country (Zengeya & Wilson 2023) and a recent comprehensive academic review (Van Wilgen et al. 2020a), the evidence base was scored as low in many cases (6 key messages scored as 'inconclusive'; 11 as 'established but incomplete'; only 5 as 'well established'). Notably, no key messages were scored as 'unresolved'. We feel that there is, with a few exceptions (Zengeya et al. 2017), general agreement among all stakeholders on the need for interventions in situations where the quality and quantity of evidence of impacts or threats is high.

Managing biological invasions

There were more differences between how we scored the objectives and actions for managing biological invasions in South Africa and how these were scored in the IPBES IAS Assessment (Table S3):

1. While prevention efforts have improved recently with the integration of biosecurity functions at ports of entry into the Border Management Authority, South Africa's geographical position means that prevention is inherently more challenging than on islands or for countries with borders that are fewer, shorter or that align with major biogeographical breaks (e.g., mountain ranges). South Africa has a substantial land border (4 862 km) that it shares with six other nations (Faulkner et al. 2017).

2. Physical methods of control were scored as being relatively ineffective in the IPBES IAS Assessment but are routinely and sometimes effectively used in South Africa (Van Wilgen et al. 2023a). Much of the physical control in South Africa might be considered 'integrated' control by others (e.g., cut-stump herbicides are often used when clearing invasive trees to prevent resprouting), but labour costs are often lower, and there are some long-term and well-established initiatives in place to address multiple socio-economic objectives, e.g., the Working for Water Programme (Van Wilgen et al. 1998; Van Wilgen et al. 2022a).

3. Possibly for some of the same reasons that physical control is relatively successful, we scored ecosystem restoration as easier in South Africa than globally (Table S3).

4. Finally, and perhaps most noticeably, there is a great deal of uncertainty in South Africa in terms of the effectiveness of most interventions. Efficacy is rarely measured. Without a feedback loop between the outcomes of interventions and decision-makers, adaptive management is not possible, and the goal of reducing biological invasions might not be met. The exception to this is that biological control interventions are often well researched, understood and highly effective.

Strategies and governance

In terms of strategies and governance, we strongly concur with a key conclusion of the IPBES IAS Assessment (key message D) - integrated governance should be improved at all levels (Table 3). Greater collaboration and coordination is needed: with neighbouring countries, across disciplines, among and between local, provincial and national government departments, and with various stakeholder groups. The recent establishment of South Africa's Border Management Authority that integrates biosecurity for animals, plants, the environment and humans with the regulation of the movement of people at ports of entry under a single command, is a notable step forward in this regard.

Whilst it will be difficult to achieve, greater flexibility is needed to ensure that management decisions are made at the most appropriate level and that proactive interventions are incentivised. A focused long-term approach that empowers relevant institutions to implement the measures necessary for the control and management of biological invasions would ensure critical decisions can be made timeously. It would also ensure interventions can adapt to changing threats and respond to successes and failures. This would require flexibility in decision-making. At the same time, much of what South Africa is doing needs to be systematised, i.e., interventions and analyses should be repeatable, and progress and successes should be tracked and shared. Monitoring of outcomes in terms of the status of invasions and feedback loops are needed to ensure that management can respond to what is happening on the ground (Ntshotsho et al. 2015). Several specific initiatives have been proposed to improve integrated governance including: stakeholder mapping, a legal review and meetings and fora to increase collaboration between all stakeholders as part of an active community of practice; with some collaborative governance programmes having been initiated (e.g., Angelstam et al. 2017; Canavan et al. 2021; Foxcroft & McGeoch 2011; Ivey et al. 2024). We also need to consider integrated governance from the perspective of the regulated community and how to leverage support (e.g., through integrated corporate governance, companies could reflect their contributions towards prevention and management of biological invasions).

Gaps

We found it generally difficult to apply the scoring used in the IPBES IAS Assessment to evaluate how addressing a gap would improve management and understanding (Table S4). Some gaps at a global level (e.g., comparatively incomplete inventories of invasive alien species in Africa and Central Asia) were not as applicable to South Africa (South Africa has relatively good inventories when compared with many countries around the world). Many of the identified actions to fill gaps (e.g., the need for systems to track the effectiveness of interventions) have already been identified as part of the South African status reports (e.g., Wilson et al. 2023) and are under consideration in the draft national strategy. There also appears to be a need to integrate global and national needs. Nonetheless, the process helped us develop some specific

actions that should be considered (e.g., the need to support general surveys of alien invertebrates and microorganisms, the need to promote transdisciplinary work and draw more on integrative social-ecological systems thinking and the need for actions to improve participation of communities in decision-making). Finally, there are a range of valuable South African specific databases and knowledge products (e.g., on research, policy, compliance and enforcement and management best practice). Consolidating such information so it is findable, accessible, inter-operable and reusable (i.e., FAIR; Wilkinson et al. 2016) as well as better co-ordination between the various organisations that collect and curate data will be essential if governance is to be integrated (Table 3).

 

Discussion

South Africa is a significant contributor to global knowledge and policy on biological invasions (Pinto et al. 2022; Van Wilgen et al. 2020a) and many authors affiliated to South Africa were involved in the IPBES IAS Assessment (Table S1). As such, it is not surprising that, in our opinion, much of the IPBES IAS Assessment resonated strongly with South African issues and priorities. Going through the exercise of comparing the IPBES IAS Assessment with the situation in South Africa provided a useful crosscheck for developing South Africa's national strategy and action plan. It also: served to strengthen our view that certain actions are key to improving how biological invasions are understood and addressed (through integrated governance in particular); highlighted where South Africa differs from other countries (Box 3); and helped us identify actions that need to be prioritised (e.g., continued funding for biological control and research across different taxa and realms, and a move towards more adaptive management). We discuss these below.

Invasive trees, invasive freshwater fishes and a substantially modified coastline

In South Africa, invasive trees (Richardson et al. 2020b) and invasive freshwater fishes (Weyl et al. 2020) are particularly problematic and rocky parts of the western and southern coastlines have been substantially modified by marine invasive species (Robinson et al. 2020; Figure 1, 2). Relative to elsewhere in the world, South Africa (especially the mainland) is much less affected by invasive vertebrates (Measey et al. 2020), and no offshore marine invaders have been recorded to date (Zengeya & Wilson 2023). There are also relatively few examples of highly damaging terrestrial arthropod invasions (Janion-Scheepers & Griffiths 2020) and plant pathogens, although the recent invasion of the polyphagous shot-hole borer (Euwallacea fornicatus) along with its fungal symbiont Fusarium euwallaceae seems set to change this (De Wit et al. 2022; Paap et al. 2018). Despite some no invasions [e.g., rinderpest, Van Helden et al. (2020)], information on invasive pests and pathogens of animals has not been as well collated into databases on invasions as it has been in other regions globally.

There has been some success in using teams of people to clear invasive trees (Fill et al. 2017; McConnachie et al. 2016), and in extirpating freshwater fishes in isolated water bodies (Weyl et al. 2014). There has also been substantial success in using biological control to manage invasive cacti, some trees and shrubs, and floating aquatic plants (Coetzee et al. 2021; Impson et al. 2021; Paterson et al. 2021). However, the ubiquitous and connected nature of the marine environment means that there is little that can be done in coastal settings once invaders have established, and so the focus must be on vigilance and pathway management to prevent incursions.

Relatively high levels of awareness and engagement?

During our discussions, we disagreed about the levels of general awareness around biological invasions in South Africa. Shackleton et al. (2020) argued that, 'certain sectors of society are more knowledgeable regarding invasions, such as elites, and those living in rural areas who are likely to be more in contact with invasions and their impacts'. However, absolute levels of knowledge are often low, e.g., Coka et al. (2024) found that 23% of rural villagers in the Eastern Cape (former Transkei region) knew Acacia dealbata was an invasive species. Studies that have monitored awareness come to differing conclusions (Cronin et al. 2017; Shackleton et al. 2015a), but from our experiences, stories about biological invasions appear regularly in newspapers and online; and some studies indicate both government officials and the public are often aware of invasive species and their impacts (Byrne et al. 2020). In discussions with international colleagues who are experts in biological invasions, levels of awareness are less than in New Zealand but greater than in much of the Americas (Box 3), Asia and other African countries. There is also broad agreement among researchers, practitioners and policy-makers as to the desirability of raising awareness about impacts and management (Van Wilgen et al. 2020a). What is clear is that efforts to raise awareness (amongst the public or specific stakeholders) have rarely been monitored in terms of their outcomes. This topic deserves much more focussed research effort so that the intended outcomes are specified and progress tracked. Systematic interdisciplinary research and monitoring (including through collaborations with social scientists and economists) could profoundly improve our understanding of the perceptions of stakeholders and facilitate management (Novoa et al. 2018), e.g., by ensuring awareness activities are tailored to particular stakeholders.

A key cross-cutting issue for the IPBES IAS Assessment (referred to in four of the 22 key messages) is the importance of 'Indigenous Peoples and local communities' (IPLC) and 'Indigenous and Local Knowledge' (ILK). The roles of IPLCs and the value of ILK was felt to be very important in the South African context, but the terminology used locally sometimes differs from that used by the IPBES. It will be important to keep the sentiment without forcing the use of a specific framework and terms (Box 4).

A vibrant community of practice

Arguably South Africa's community of invasion scientists, managers and practitioners is neither too small that major issues are not addressed nor too large that they cannot regularly meet as a group. There is a sufficient diversity of practitioners with some turnover of both scientific and managerial staff so that there is institutional memory and willingness to continue group discussions over long periods of time (e.g., Davies et al. 2020a). This community of practice hits a Goldilocks zone, small enough to be intimate, connected, collaborative and continue over time without too much irrelevant bureaucracy, but not so small that it relies on a few individuals (Foxcroft et al. 2020).

South Africa is well placed in terms of specific governmental institutions that focus on directed applied research and coordination (e.g., the Agricultural Research Council, the Council for Scientific and Industrial Research and the South African National Biodiversity Institute). The government department in charge of fundamental research values applied research, and the departments in charge of environmental affairs and agriculture recognise the importance of foundational research, providing support to scientists through research grants and postgraduates through various bursary schemes.

Invasion science, as a discipline, allows for training in a real-world problem that cuts across different sectors and in which a tangible difference can be made by individual students. For almost two decades (2004-2022), the South African government funded a world-leading institute with the aim of conducting research, education and training, coordinating networking, information brokerage and service provision relating to biological invasions (the Centre for Invasion Biology, Richardson et al. 2020a). Similarly, a research centre dedicated to biological control research, training and implementation has provided vital support to managers across the country (the Centre for Biological Control, Byrne et al. 2020). Ensuring such initiatives continue will be crucial if the national strategy is to be effective.

Various methods are used to increase interactions, including joint attendance and participation in voluntary fora and conference series where researchers and managers are regularly exposed to each other's challenges (Foxcroft et al. 2020). There is an annual National Symposium on Biological Invasions that regularly has an attendance of over one hundred delegates including researchers, academics and policy- and decision-makers from various government departments. Government officials are also encouraged to attend training [e.g., short courses in biological control and risk analysis have been developed and led by academics and staff of research institutions (Byrne et al. 2020; Wilson & Kumschick 2024)] or to register for post-graduate qualifications. Other initiatives that have been in place are management and research planning fora. Some have run their course, but others have been ongoing for many years, including working groups on cacti, grasses and invasive animals (Davies et al. 2020a; Kaplan et al. 2017; Visser et al. 2017).

A substantial existing knowledge base but one that can be rapidly expanded

Biological invasions have been reasonably well-documented in protected areas (Van Wilgen & Herbst 2017), as well as across the whole country for plants (Henderson & Wilson 2017). There has also been a growing use of citizen science platforms (e.g., iNaturalist) to facilitate monitoring and reporting in South Africa (Potgieter et al. 2024; Zengeya & Wilson 2023). There is still a need, however, for inventories of cultivated aliens and cultivated areas (this was notably outside the scope of the IPBES IAS Assessment). Angling, arboreta, botanical gardens, horticulture, the pet trade and zoos often use alien taxa and information on these need to be incorporated into our thinking (Cheek et al. 2022; Glen 2002; Vezi et al. 2024; Wondafrash et al. 2021). Pathway-specific risk assessments and management plans are also needed.

Importantly, there is still much to be gained from more interdisciplinary and transdisciplinary research - much of the research on biological invasions is still driven by a core group of ecologists (Abrahams et al. 2019). For example, arguably social and gender issues as outlined in the IPBES approach are not adequately addressed [though studies have looked at the value of overt targets for gender and the need to consider social redress in interventions (Hough & Prozesky 2012, 2013; Sadan 2005; Van Koppen et al. 2011)]. It will be important to ensure the proposed national strategy elicits contributions from the social sciences and incorporates discourses from different perspectives.

Integrated governance

We agree strongly with the plea in the IPBES IAS Assessment for more focus on integrated governance. For example, provincial legislation on keeping pets differs

throughout the country with some provinces allowing many alien pets, while others ban most (Nelufule et al. 2020). We often have the tools, frameworks and knowledge necessary to address biological invasions, and in many cases these have been adapted specifically to the South African context. We argue for a greater focus on how we implement. Improvements to project management (e.g., supply chain management) could greatly increase the effectiveness of control projects funded by the government. It will be important to focus management on where and when it is needed most, and ensure monitoring is sufficient to allow for management to be adaptive.

Humans are both the cause of and solution to biological invasions. Effective management requires co-ordination across different mandates, sectors (e.g., agriculture, health and transport) and scales (local to national). Several promising cross-cutting approaches have been identified with links to biological invasions, including One Health (Ogden et al. 2019) and One Biosecurity (Hulme 2020). The challenge (in particular for the national strategy) is to improve coordination while limiting bureaucracy to that which is needed. We believe there is room both for a forum dedicated to biological invasions (for those who work directly on the issue) and for a broader inter-agency One Biosecurity Commission (that brings together those working on animal, environmental, human and plant health; cf. the Presidential Climate Commission https://www.climate-commission.org.za/ established in Sep. 2020).

Biological invasions do not respect administrative borders, and all agreed on the need for greater collaboration with neighbouring countries, the Southern African Development Community (SADC) and Africa more generally. It will be vital for Africa to share experiences and collectively address biological invasions (Faulkner et al. 2017), particular in light of the African Continental Free Trade Area that was established in 2019 (Faulkner et al. 2020a).

Resourcing and where to from here

The amount of resources invested to address biological invasions in South Africa is substantial but declining (McCulloch-Jones et al. 2024; Van Wilgen et al. 2022a).

There is a specific and substantial value proposition in preventing and controlling biological invasions. This needs to be made more strongly. A greater investment of resources in proactive management would do much to limit future biological invasions (McCulloch-Jones et al. 2024) especially in the context of environmental biosecurity (Early et al. 2016). Substantial returns on investment have, however, also been made by treating existing widespread invasions, especially through clearing trees in water source areas (McConnachie et al. 2012; Stafford et al. 2019) and classical biological control (McConnachie et al. 2003; Van Wilgen & De Lange 2011). Since 2022, national government funding for biocontrol has not been forthcoming even though South Africa has a long and successful history of research and implementation in this area (Hill et al. 2020). This suggests the need to both improve how the case for safe and effective biological control is made to the South African government and to diversify funding options, for example, with more public-private partnerships (Ivey et al. 2024; Martin et al. 2018). We advocate strongly that funds to improve human health, agricultural productivity and food security, livelihoods and the economy can be highly effective if invested in addressing biological invasions.

There are, as always, challenges that could severely limit management options in future. A ban on herbicides would remove essential tools for control (integrated control linking mechanical removal with chemical control is imperative for many invasive trees); the push for commercialisation has the potential to open up new introduction pathways; and perverse incentives to address climate change through afforestation using alien species has led to widespread damaging invasions (Bond et al. 2019).

During our discussions, and as flagged by many parties during consultations, much more integration and collaboration with neighbouring countries are urgently needed if biological invasions are to be effectively addressed. Although South Africa was well represented in the IPBES IAS Assessment, several concerns were expressed at the IPBES plenary (during which the assessment was approved) pertaining to data gaps and low representation of experts from developing countries. South Africa's draft national strategy recognises this. Opportunities for funding through the Global Biodiversity Framework Fund and various international initiatives could provide valuable sources of seed funding to facilitate greater integration of efforts within SADC and Africa more broadly.

This paper is a selected view by a selected group in response to a particular initiative (the IPBES IAS Assessment). The South African status report provided background information but was not explicitly reviewed here. This paper also does not explicitly review the historical context [for a broad review of biological invasions in South Africa see Van Wilgen et al. (2020a)]. Key sectors from South Africa did not contribute to the IPBES IAS Assessment (and so were not included as authors of this paper), in particular microbiologists, fungal biologists and human health specialists; a more diverse range of viewpoints would be extremely valuable. A much broader analysis using a range of tools from futures thinking (including environmental scanning, driver mapping, horizon scanning and scenario planning) would also provide significant insights for the national strategy and action plan (Hulme 2025). Nonetheless, we believe this paper provides an important perspective linking international best practice and insights (the IPBES IAS Assessment) to national needs (the draft national strategy).

 

Conclusion

The IPBES IAS Assessment is a landmark report at the science-policy interface on biological invasions that, we argue, provides guidance for South Africa to deal with biological invasions. The IPBES IAS Assessment provides compelling evidence of the need for immediate and urgent control of invasive species, serving as a baseline to monitor progress towards Target 6 of the Kunming-Montreal Global Biodiversity Framework. Nonetheless, given the focus of the IPBES IAS Assessment (global and holistic), the key messages and gaps will likely not wholly resonate for any specific country. We encourage readers in South Africa and other countries to go beyond the key messages from the IPBES IAS Assessment and contextualise and scrutinise the findings based on what is important for their region or country. This opinion paper hopefully provides insights both for how South Africa can contribute to the implementation of CBD Article 8h and to Target 6 of the KM-GBF, what South Africa's national strategy should include, and, ultimately, how South Africa can be protected from the harm caused by biological invasions for the benefit of the environment and human well-being.

 

Acknowledgements

We thank our late colleagues Kay Montgomery, John Measey and Olaf Weyl for their contributions to the IPBES IAS Assessment, the South African status reports, and the science and management of biological invasions in South Africa. They are missed. We thank Cavin Shivambu, Ndivhuwo Shivambu, Tanara Renard Truong and Felipe Balocchi Schalchli for their comments on previous versions of this manuscript.

Competing interests

Most of the authors are involved in management and research on biological invasions in South Africa. Several of the authors contributed to the IPBES IAS Assessment (see legend to Table S1).

Authors' contributions

Conceptualisation (JRUW, KTF, LFW, EJMcC-J, SM, BWvW, TAZ); project administration (JRUW); visualisation [CC (Figure 1); EJMcC-J, KTF, RB (Figure 2)]; writing - original draft [JRUW, KTF, LFW, EJMcC-J, SM, DMR, TBR, SK, NT, FT, SJR, BWvW, TAZ; JRUW (Box 1); KTF, LFW, MG, PClR (Box 2); MSD, SRZ (Box 3); RB, SJR (Box 4)]; writing - review and editing (all). All authors have read and agreed to the published version of the manuscript.

Funding

The South African Department of Forestry, Fisheries, and the Environment (DFFE) are thanked for funding, noting that this publication does not necessarily represent the views or opinions of DFFE or its employees. The Department of Science and Innovation (DSI) funded the DSI-NRF [National Research Foundation] Centre of Excellence for Invasion Biology from 2004 to 2024; much of the research presented here arose from that funding. The involvement of many of the authors in the IPBES IAS Assessment was only possible through support from IPBES and in particular the relevant technical support unit. BWvW thanks the National Research Foundation of South Africa for funding (Grant Numbers 150260 and 151653).

 

References

Abrahams, B., Sitas, N. & Esler, K.J., 2019, 'Exploring the dynamics of research collaborations by mapping social networks in invasion science', Journal of Environmental Management, 229, 27-37, https://doi.org/10.1016/j.jen-vman.2018.06.051.         [ Links ]

Angelstam, P., Barnes, G., Elbakidze, M., Marais, C., Marsh, A., Polonsky, S., Richardson, D.M., Rivers, N., Shackleton, N.T. & Stafford, W., 2017, 'Collaborative learning to unlock investments for functional ecological infrastructure: Bridging barriers in social-ecological systems in South Africa', Ecosystem Services, 27, 291-304, https://doi.org/10.1016/j.ecoser.2017.04.012.         [ Links ]

Bellard, C., Leroy, B., Thuiller, W., Rysman, J.F. & Courchamp, F., 2016, 'Major drivers of invasion risks throughout the world', Ecosphere, 7, e01241, https://doi.org/10.1002/ecs2.1241.         [ Links ]

Bester, M.N., Bloomer, J.P., Van Aarde, R.J., Erasmus, B.H., Van Rensburg, P.J.J., Skinner, J.D., Howell, P.G. & Naude, T.W., 2002, 'A review of the successful eradication of feral cats from sub-Antarctic Marion Island, Southern Indian Ocean', South African Journal of Wildlife Research, 32, 6573, https://journals.co.za/doi/pdf/10.10520/EJC117137.         [ Links ]

Bond, W.J., Stevens, N., Midgley, G.F. & Lehmann, C.E.R., 2019, 'The trouble with trees: afforestation plans for Africa', Trends in Ecology & Evolution, 34, 963-965, https://doi.org/10.1016/j.tree.2019.08.003.         [ Links ]

Byrne, M.J., Davies, S.J., du Plessis, D., Ivey, P.J., Measey, J., Robertson, M.P., Robinson, T.B. & Weaver, K.N., 2020, 'Education, training and capacity building in the field of biological invasions in South Africa', in B.W. van Wilgen, J. Measey, D.M. Richardson, J.R. Wilson & T.A. Zengeya (eds.), Biological invasions in South Africa, Springer, Cham, Switzerland, https://doi.org/10.1007/978-3-030-32394-3_25.         [ Links ]

Canavan, K., Paterson, I.D., Ivey, P., Sutton, G.F. & Hill, M.P., 2021, 'Prioritisation of targets for weed biological control III: a tool to identify the next targets for biological control in South Africa and set priorities for resource allocation', Biocontrol Science and Technology, 31, 584-601, https://doi.org/10.1080/09583157.2021.1918638.         [ Links ]

CBD. 2023. The Biodiversity Plan for Life on Earth: Target 6, viewed 11 June 2024, from https://www.cbd.int/gbf/targets/6.         [ Links ]

Cheek, M.D., Wilson, J.R.U., Richardson, D.M. & Procheş, Ş., 2022, 'The status of arboreta in South Africa and the taxa they contain', Southern Forests: a Journal of Forest Science, 84, 174-191, https://doi.org/10.2989/20702620.2022.2102453.         [ Links ]

Coetzee, J.A., Bownes, A., Martin, G.D., Miller, B.E., Smith, R., Weyl, P.S.R. & Hill, M.P., 2021, 'A review of the biocontrol programmes against aquatic weeds in South Africa', African Entomology, 29, 935-964, https://doi.org/10.4001/003.029.0935.         [ Links ]

Coka, N., Thondhlana, G. & Ruwanza, S., 2024, 'Perceptions of Acacia dealbata invasion and clearing in upper Tsitsana villages in the Eastern Cape Province of South Africa', Forests, Trees and Livelihoods, 33, 101-117, https://doi.org/10.1080/14728028.2024.2304172.         [ Links ]

Cronin, K., Kaplan, H., Gaertner, M., Irlich, U. & Hoffman, M.T., 2017, 'Aliens in the nursery: assessing the attitudes of nursery managers to invasive species regulations', Biological Invasions, 19, 925-937, https://doi.org/10.1007/S10530-016-1363-3.         [ Links ]

Davies, S.J., Bell, J.A., Impson, D., Mabin, C., Meyer, M., Rhoda, C., Stafford, L., Stephens, K., Tafeni, M., Turner, A.A., Van Wilgen, N.J., Wilson, J.R.U., Wood, J. & Measey, J., 2020a, 'Coordinating invasive alien species management in a biodiversity hotspot: The CAPE Invasive Alien Animals Working Group', Bothalia - African Biodiversity & Conservation, 50, a10, https://doi.org/10.38201/btha.abc.v50.i1.10.         [ Links ]

Davies, S.J., Jordaan, M.S., Karsten, M., Terblanche, J.S., Turner, A.A., Van Wilgen, N.J., Veldtman, R., Zengeya, T.A. & Measey, J., 2020b, 'Experience and lessons from alien and invasive animal control projects in South Africa', in B.W. van Wilgen, J. Measey, D.M. Richardson, J.R. Wilson & T.A. Zengeya (eds.), Biological invasions in South Africa, Springer, Cham, Switzerland, https://doi.org/10.1007/978-3-030-32394-3_22.         [ Links ]

De Villiers, M.S. & Cooper, J., 2008, 'Conservation and management', in S.L. Chown & P.W. Froneman (eds), The Prince Edward Islands: Land-Sea Interactions in a Changing Ecosystem, SUN PReSS, Stellenbosch, https://scispace.com/pdf/the-prince-edward-islands-land-sea-interactions-in-a-3bo79aqkmx.pdf.         [ Links ]

De Wit, M.P, Crookes, D.J., Blignaut, J.N., De Beer, Z.W., Paap, T., Roets, F., Van der Merwe, C., Van Wilgen, B.W. & Richardson, D.M., 2022, 'An assessment of the potential economic impacts of the invasive polyphagous shot hole borer (Coleoptera: Curculionidae) in South Africa', Journal of Economic Entomology, 115, 1076-1086, https://doi.org/10.1093/jee/toac061.         [ Links ]

De Wit, M.P, Crookes, D.J. & Van Wilgen, B.W., 2001, 'Conflicts of interest in environmental management: estimating the costs and benefits of a tree invasion', Biological Invasions, 3, 167-178, https://doi.org/10.1023/A:1014563702261.         [ Links ]

Dechoum, M.S., Junqueira, A.d.O.R., Orsi, M.L., Ziller, S.R., Pivello, V.R., Zenni, R.D., Thomaz, S.M., Fonseca, A.C., Vitule, J.R.S., Barros, F., Ivanauskas, N.M., Creed, J., Brito, M.F.G., Bergallo, H.G., Rocha, R.M. & Galheigo, F.A., 2024, 'Open-access thematic assessment report on invasive alien species in Brazil: summary for policy-makers', Biota Neotropica, 24, e20241645, https://doi.org/10.1590/1676-0611-BN-2024-1645.         [ Links ]

Department of Environmental Affairs, 2010, Department of Environmental Affairs Directorate: Antarctica and Islands. Prince Edward Islands Management Plan Version 0.2, pp. 202, https://www.dffe.gov.za/sites/default/files/docs/strategy.framework/oceans/princeedward_islands_managementplan.pdf.         [ Links ]

Department of Environment, Forestry and Fisheries, 2023, 'White Paper on the conservation and sustainable use of South Africa's biodiversity', Government Gazette, notice 3537 of 2023, no. 48785, 14 June 2023, 3-43.         [ Links ]

Early, R., Bradley, B.A., Dukes, J.S., Lawler, J.J., Olden, J.D., Blumenthal, D.M., Gonzalez, P., Grosholz, E.D., Ibañez, I., Miller, L.P., Sorte, C.J.B & Tatem, A.J., 2016, 'Global threats from invasive alien species in the twenty-first century and national response capacities', Nature Communications, 7, 9, https://doi.org/10.1038/ncomms12485.         [ Links ]

Faulkner, K.T., 2023, 'Chapter 1: Pathways', in T.A. Zengeya & J.R. Wilson (eds), The status of biological invasions and their management in South Africa in 2022, South African National Biodiversity Institute, Kirstenbosch and DSI-NRF Centre of Excellence for Invasion Biology, Stellenbosch, https://doi.org/10.5281/zenodo.8217182.         [ Links ]

Faulkner, K.T., Burness, A., Byrne, M., Kumschick, S., Peters, K., Robertson, M.P., Saccagii, D.L., Weyl, O.L.F. & Williams, V.L., 2020a, 'South Africa's pathways of introduction and dispersal and how they have changed over time', in B.W. van Wilgen, J. Measey, D.M. Richardson, J.R. Wilson & T.A. Zengeya (eds.), Biological invasions in South Africa, Springer, Cham, Switzerland, https://doi.org/10.1007/978-3-030-32394-3_12.         [ Links ]

Faulkner, K.T., Hurley, B.P., Robertson, M.P., Rouget, M. & Wilson, J.R.U., 2017, 'The balance of trade in alien species between South Africa and the rest of Africa', Bothalia - African Biodiversity & Conservation, 47, a2157, https://doi.org/10.4102/abc.v47i2.2157.         [ Links ]

Faulkner, K.T., Robertson, M.P., Rouget, M. & Wilson, J.R.U., 2016, 'Understanding and managing the introduction pathways of alien taxa: South Africa as a case study', Biological Invasions, 18, 73-87, https://doi.org/10.1007/s10530-015-0990-4.         [ Links ]

Faulkner, K.T., Robertson, M.P. & Wilson, J.R.U., 2020b, 'Stronger regional biosecurity is essential to prevent hundreds of harmful biological invasions', Global Change Biology, 26, 2449-2462, https://doi.org/10.1111/gcb.15006.         [ Links ]

Fernández Winzer, L., Greve, M., le Roux, P., Faulkner, K. & Wilson, J., 2025, 'Using indicators to assess the status of biological invasions and their management on islands: the Prince Edward Islands, South Africa as an example', Biological Invasions, 27, a108, https://doi.org/10.1007/s10530-024-03463-7.         [ Links ]

Fernández Winzer, L., Greve, M., Le Roux, P.C., Faulkner, K.T. & Wilson, J.R., 2023, 'Chapter 5: The status of biological invasions and their management in the Prince Edward Islands', in T.A. Zengeya & J.R. Wilson (eds.), The status of biological invasions and their management in South Africa in 2022, South African National Biodiversity Institute, Kirstenbosch and DSI-NRF Centre of Excellence for Invasion Biology, Stellenbosch, pp. 75-99, https://doi.org/10.5281/zenodo.8217182.         [ Links ]

Fill, J.M., Forsyth, G.G., Kritzinger-Klopper, S., Le Maitre, D.C. & Van Wilgen, B.W., 2017, 'An assessment of the effectiveness of a long-term ecosystem restoration project in a fynbos shrubland catchment in South Africa', Journal of Environmental Management, 185, 1-10, https://doi.org/10.1016/j.jenvman.2016.10.053.         [ Links ]

Foxcroft, L.C. & McGeoch, M., 2011, 'Implementing invasive species management in an adaptive management framework', Koedoe, 53, https://doi.org/10.4102/koedoe.v53i2.1006.         [ Links ]

Foxcroft, L.C., Van Wilgen, B.W., Abrahams, B., Esler, K.J. & Wannenburgh, A., 2020, 'Knowing-doing continuum or knowing-doing gap? Information flow between researchers and managers of biological invasions in South Africa', in B.W. van Wilgen, J. Measey, D.M. Richardson, J.R. Wilson & T.A. Zengeya (eds), Biological invasions in South Africa, Springer, Cham, Switzerland, https://doi.org/10.1007/978-3-030-32394-3_28.         [ Links ]

García-de-Lomas, J. & Vilà, M., 2015, 'Lists of harmful alien organisms: Are the national regulations adapted to the global world?', Biological Invasions, 17, 3081-3091, https://doi.org/10.1007/s10530-015-0939-7.         [ Links ]

Glen, H.F., 2002, Cultivated plants of southern Africa, Johannesburg, South Africa, South African National Biodiversity Institute and Jacana.         [ Links ]

Graziosi, I., Tembo, M., Kuate, J. & Muchugi, A., 2020, 'Pests and diseases of trees in Africa: A growing continental emergency', Plants, People, Planet, 2, 14-28, https://doi.org/10.1002/ppp3.31.         [ Links ]

Greve, M., Mathakutha, R., Steyn, C. & Chown, S.L., 2017, 'Terrestrial invasions on sub-Antarctic Marion and Prince Edward Islands', Bothalia - African Biodiversity & Conservation, 47, a2143, https://doi.org/10.4102/abc.v47i2.2143.         [ Links ]

Greve, M., Von der Meden, C.E.O. & Janion-Scheepers, C., 2020, 'Biological invasions in South Africa's offshore sub-Antarctic territories', in B.W. van Wilgen, J. Measey, D.M. Richardson, J.R. Wilson & T.A. Zengeya (eds), Biological invasions in South Africa, Springer, Cham, Switzerland, https://doi.org/10.1007/978-3-030-32394-3_8.         [ Links ]

Henderson, L. & Wilson, J.R.U., 2017, 'Changes in the composition and distribution of alien plants in South Africa: an update from the Southern African Plant Invaders Atlas', Bothalia - African Biodiversity & Conservation, 47, a2142, https://doi.org/10.4102/abc.v47i2.2172.         [ Links ]

Herbert, D.G. & Sirgel, W.F., 2001, 'The recent introduction of two potentially pestiferous alien snails into South Africa and the outcomes of different pest management practices: an eradication and a colonization', South African Journal of Science, 97, 301-304, https://hdl.handle.net/10520/EJC97346.         [ Links ]

Hill, M.P. & Coetzee, J., 2017, 'The biological control of aquatic weeds in South Africa: current status and future challenges', Bothalia - African Biodiversity & Conservation, 47, a2152, https://doi.org/10.4102/abc.v47i2.2152.         [ Links ]

Hill, M.P., Moran, V.C., Hoffmann, J.H., Neser, S., Zimmermann, H.G., Simelane, D.O., Klein, H., Zachariades, C., Wood, A.R., Byrne, M.J., Paterson, I.D., Martin, G.D. & Coetzee, J.A., 2020, 'More than a century of biological control against invasive alien plants in South Africa: a synoptic view of what has been accomplished', in B.W. van Wilgen, J. Measey, D.M. Richardson, J.R. Wilson & T.A. Zengeya (eds.), Biological invasions in South Africa, Springer, Cham, Switzerland, https://doi.org/10.1007/978-3-030-32394-3_19.         [ Links ]

Holmes, FIM., Esler, K.J., Gaertner, M., Geerts, S., Hall, S.A., Nsikani, M.M., Richardson, D.M. & Ruwanza, S., 2020, 'Biological invasions and ecological restoration in South Africa', in B.W. van Wilgen, J. Measey, D.M. Richardson, J.R. Wilson & T.A. Zengeya (eds.), Biological invasions in South Africa, Springer, Cham, Switzerland, https://doi.org/10.1007/978-3-030-32394-3_23.         [ Links ]

Hough, J.A. & Prozesky, H., 2012, 'Beneficiaries' aspirations to permanent employment within the South African Working for Water Programme', Social Dynamics, 38, 331-349, https://doi.org/10.1080/02533952.2012.719395.         [ Links ]

Hough, J.A. & Prozesky, H.E., 2013, ''I don't want to go back to the farm': A case study of Working for Water beneficiaries', South African Journal of Science, 109, 8, https://doi.org/10.1590/sajs.2013/1119.         [ Links ]

Hulme, P.E., 2020, 'One Biosecurity: a unified concept to integrate human, animal, plant, and environmental health', Emerging Topics in Life Sciences, 4, 539-549, https://doi.org/10.1042/etls20200067.         [ Links ]

Hulme, P.E., 2021, 'Unwelcome exchange: International trade as a direct and indirect driver of biological invasions worldwide', One Earth, 4, 666-679, https://doi.org/10.1016/j.oneear.2021.04.015.         [ Links ]

Hulme, P.E., 2022, 'Importance of greater interdisciplinarity and geographic scope when tackling the driving forces behind biological invasions', Conservation Biology, 36, https://doi.org/10.1111/cobi.13817.         [ Links ]

Hulme, P.E., 2025, 'Trouble on the horizon: anticipating biological invasions through futures thinking', Biological Reviews, 100, 461-480, https://doi.org/10.1111/brv.13149.         [ Links ]

Huntley, B.J., 1987, '10 years of cooperative ecological research in South Africa', South African Journal of Science, 83, 72-79, https://hdl.handle.net/10520/AJA00382353_6163.         [ Links ]

Impson, F.A.C., Kleinjan, C.A., Hoffmann, J.H. & Mudavanhu, P., 2021, 'A review of research and developments with insect agents used for biological control of Australian Acacia species (Caesalpinioideae) in South Africa', African Entomology, 29, 693-712, https://doi.org/10.4001/003.029.0693.         [ Links ]

IPBES, 2018a, Information on scoping for a thematic assessment of invasive alien species and their control (deliverable 3 (b)(ii)). IPBES/2/16/Add.3, Antalya, Turkey.         [ Links ]

IPBES, 2018b, IPBES Guide on the production of assessments, Secretariat of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services, Bonn, Germany.         [ Links ]

IPBES, 2022, Methodological assessment of the diverse values and valuation of nature of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services, Bonn, Germany, IPBES Secretariat, https://doi.org/10.5281/zenodo.6522522.         [ Links ]

IPBES, 2023a, 'Summary for policymakers of the thematic assessment report on invasive alien species and their control of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services', in H.E. Roy, A. Pauchard, P. Stoett, T. Renard Truong, S. Bacher, B.S. Galil, P.E. Hulme, T. Ikeda, K.V. Sankaran, M.A. McGeoch, L.A. Meyerson, M.A. Nuñez, A. Ordonez, S.J. Rahlao, E. Schwindt, H. Seebens, A.W. Sheppard & V. Vandvik, (eds), IPBES Secretariat, Bonn, Germany, https://doi.org/10.5281/zenodo.7430692        [ Links ]

IPBES, 2023b, 'Thematic assessment report on invasive alien species and their control of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services', in H.E. Roy, A. Pauchard, P. Stoett & T. Renard Truong, (eds), IPBES Secretariat, Bonn, Germany, https://doi.org/10.5281/zenodo.7430682.         [ Links ]

Ivey, P, Van Staden, G., Harding, G., Oosthuizen, D., Hoft, E., Van Staden, P., Anthonissen, E., Weaver, K., Hill, M. & Shackleton, R., 2024, 'Local and national stakeholders collaborate to take on Prosopis invasions with biological control and biomass use in South Africa', South African Journal of Science, 120, 9/10, pp. 9, https://doi.org/10.17159/sajs.2024/17928.         [ Links ]

Janion-Scheepers, C. & Griffiths, C.L., 2020, 'Alien terrestrial invertebrates in South Africa', in B.W. van Wilgen, J. Measey, D.M. Richardson, J.R. Wilson & T.A. Zengeya (eds), Biological invasions in South Africa, Springer, Cham, Switzerland, https://doi.org/10.1007/978-3-030-32394-3_7.         [ Links ]

Jubase, N., Shackleton, R.T. & Measey, J., 2021, 'Motivations and contributions of volunteer groups in the management of invasive alien plants in South Africa's Western Cape province', Bothalia - African Biodiversity & Conservation, 51, https://doi.org/10.38201/btha.abc.v51.i2.3.         [ Links ]

Kaplan, H., Wilson, J.R.U., Klein, H., Henderson, L., Zimmermann, H.G., Manyama, P., Ivey, P., Richardson, D.M. & Novoa, A., 2017, 'A proposed national strategic framework for the management of Cactaceae in South Africa', Bothalia - African Biodiversity & Conservation, 47, a2149, https://doi.org/10.4102/abc.v47i2.2149.         [ Links ]

Klein, H., Zimmermann, H.G. & Xivuri, T., 2020, 'Exceptional biological control of two varieties of Cylindropuntia fulgida (Cactaceae) in South Africa using a recently-identified different biotype of the cochineal insect, Dactylopius tomentosus (Dactylopiidae)', Biological Control, 149, 104314, https://doi.org/10.1016/j.biocontrol.2020.104314.         [ Links ]

Kraaij, T., Baard, J.A., Arndt, J., Vhengani, L. & Van Wilgen, B.W., 2018, 'An assessment of climate, weather, and fuel factors influencing a large, destructive wildfire in the Knysna region, South Africa', Fire Ecology, 14, https://doi.org/10.1186/s42408-018-0001-0.         [ Links ]

Kraaij, T., Baard, J.A., Rikhotso, D.R., Cole, N.S. & Van Wilgen, B.W., 2017, 'Assessing the effectiveness of invasive alien plant management in a large fynbos protected area', Bothalia - African Biodiversity & Conservation, 47, a2105, https://doi.org/10.4102/abc.v47i2.2105.         [ Links ]

Kumschick, S., Foxcroft, L.C. & Wilson, J.R., 2020, 'Analysing the risks posed by biological invasions to South Africa', in B.W. van Wilgen, J. Measey, D.M. Richardson, J.R. Wilson & T.A. Zengeya (eds), Biological invasions in South Africa, Springer, Cham, Switzerland, https://doi.org/10.1007/978-3-030-32394-3_20.         [ Links ]

Langhammer, PIF., Bull, J.W., Bicknell, J.E., Oakley, J.L., Brown, M.H., Bruford, M.W., Butchart, S.H.M., Carr, J.A., Church, D., Cooney, R., Cutajar, S., Foden, W., Foster, M.W., Gascon, C., Geldmann, J., Genovesi, P., Hoffmann, M., Howard-McCombe, J., Lewis, T., MacFarlane, N.B.W., Melvin, Z.E., Merizalde, R.S., Morehouse, M.G., Pagad, S., Polidoro, B., Sechrest, W., Segelbacher, G., Smith, K.G., Steadman, J., Strongin, K., Williams, J., Woodley, S. & Brooks, T.M., 2024, 'The positive impact of conservation action', Science, 384, 453-458, https://doi.org/doi:10.1126/science.adj6598.         [ Links ]

Latombe, G., Canavan, S., Hirsch, H., Hui, C., Kumschick, S., Nsikani, M.M., Potgieter, L., Robinson, T.B., Saul, W.-C., Turner, S.C., Wilson, J.R., Yannelli, F. & Richardson, D.M., 2019, 'A four-component classification of uncertainties in biological invasions: implications for management', Ecosphere, 10, e02669, https://doi.org/10.1002/ecs2.2669.         [ Links ]

Le Maitre, D.C., Blignaut, J.N., Clulow, A., Dzikiti, S., Everson, C.S., Görgens, A.H.M. & Gush, M.B., 2020, 'Impacts of invasions on terrestrial water resources in South Africa', in B.W. van Wilgen, J. Measey, D.M. Richardson, J.R. Wilson & T.A. Zengeya (eds), Biological invasions in South Africa, Springer, Cham, Switzerland, https://doi.org/10.1007/978-3-030-32394-3_15.         [ Links ]

Le Maitre, D.C., Forsyth, G.G., Dzikiti, S. & Gush, M.B., 2016, 'Estimates of the impacts of invasive alien plants on water flows in South Africa', Water SA, 42, 659-672, https://doi.org/10.4314/wsa.v42i4.17.         [ Links ]

Le Maitre, D.C. & Gorgens, A., 2003, Impact of invasive alien species on dam yields, Water Research Commission, Pretoria.         [ Links ]

Lukey, P. & Hall, J., 2020, 'Biological invasion policy and legislation development and implementation in South Africa', in B.W. van Wilgen, J. Measey, D.M. Richardson, J.R. Wilson & T.A. Zengeya (eds), Biological invasions in South Africa, Springer, Cham, Switzerland, https://doi.org/10.1007/978-3-030-32394-3_18.         [ Links ]

MacFadyen, S., Allsopp, N., Altwegg, R., Archibald, S., Botha, J., Bradshaw, K., Carruthers, J., De Klerk, H., De Vos, A., Distiller, G., Foord, S., Freitag-Ronaldson, S., Gibbs, R., Hamer, M., Landi, P., MacFayden, D., Manuel, J., Midgley, G., Moncrieff, G., Munch, Z., Mutanga, O., Sershen, Nenguda, R., Ngwenya, M., Parker, D., Peel, M., Power, J., Pretorius, J., Ramdhani, S., Robertson, M., Rushworth, I., Skowno, A., Slingsby, J., Turner, A., Visser, V., Van Wageningen, G. & Hui, C., 2022, 'Drowning in data, thirsty for information and starved for understanding: A biodiversity information hub for cooperative environmental monitoring in South Africa', Biological Conservation, 274, 109736, https://doi.org/10.1016/j.biocon.2022.109736.         [ Links ]

Martin, G.D., Hill, M.P., Coetzee, J.A., Weaver, K.N. & Hill, J.M., 2018, 'Synergies between research organisations and the wider community in enhancing weed biological control in South Africa', Biocontrol, 63, 437-447, https://doi.org/10.1007/s10526-017-9846-4.         [ Links ]

Mazza, G., Tricarico, E., Genovesi, P. & Gherardi, F., 2014, 'Biological invaders are threats to human health: an overview', Ethology Ecology & Evolution, 26, 112-129, https://doi.org/10.1080/03949370.2013.863225.         [ Links ]

McConnachie, A.J., De Wit, M.P., Hill, M.P. & Byrne, M.J., 2003, 'Economic evaluation of the successful biological control of Azolla filiculoides in South Africa', Biological Control, 28, 25-32, https://doi.org/10.1016/S1049-9644(03)00056-2.         [ Links ]

McConnachie, M.M., Cowling, R.M., Van Wilgen, B.W. & McConnachie, D.A., 2012, 'Evaluating the cost-effectiveness of invasive alien plant clearing: a case study from South Africa', Biological Conservation, 155, 128-135, https://doi.org/10.1016/j.biocon.2012.06.006.         [ Links ]

McConnachie, M.M., Van Wilgen, B.W., Ferraro, P.J., Forsyth, A.T., Richardson, D.M., Gaertner, M. & Cowling, R.M., 2016, 'Using counterfactuals to evaluate the cost-effectiveness of controlling biological invasions', Ecological Applications, 26, 475-483, https://doi.org/10.1890/15-0351.1.         [ Links ]

McCulloch-Jones, E.J., Cuthbert, R.N., Van Wilgen, B.W. & Wilson, J.R.U., 2024, 'Estimating the monetary cost of biological invasions to South Africa', Biological Invasions, 26, 3191-3203, https://doi.org/10.1007/s10530-024-03369-4.         [ Links ]

McElwee, P., Fernández-Llamazares, Á., Aumeeruddy-Thomas, Y., Babai, D., Bates, P., Galvin, K., Gueze, M., Liu, J., Molnar, Z., Ngo, H.T., Reyes-Garcia, V., Chowdhury, R.R., Samakov, A., Shrestha, U.B., Diaz, S. & Brondízio, E.S., 2020, 'Working with Indigenous and local knowledge (ILK) in large-scale ecological assessments: Reviewing the experience of the IPBES Global Assessment', Journal of Applied Ecology, 57, 1666-1676, https://doi.org/10.1111/1365-2664.13705.         [ Links ]

McGeoch, M.A., Genovesi, P., Bellingham, P.J., Costello, M.J., McGrannachan, C. & Sheppard, A., 2016, 'Prioritizing species, pathways, and sites to achieve conservation targets for biological invasion', Biological Invasions, 18, 299314, https://doi.org/10.1007/s10530-015-1013-1.         [ Links ]

Measey, J., Hui, C. & Somers, M., 2020, 'Terrestrial vertebrate invasions in South Africa', in B.W. van Wilgen, J. Measey, D.M. Richardson, J.R. Wilson & T.A. Zengeya (eds), Biological invasions in South Africa, Springer, Cham, Switzerland, https://doi.org/10.1007/978-3-030-32394-3_5.         [ Links ]

Measey, J., Visser, V., Dgebuadze, Y., Inderjit, Li, B., Dechoum, M., Ziller, S.R. & Richardson, D.M., 2019, 'The world needs BRICS countries to build capacity in invasion science', PLOS Biology, 17, e3000404, https://doi.org/10.1371/journal.pbio.3000404.         [ Links ]

Mukwada, G., Chingombe, W. & Taru, P., 2016, 'Strifes of the frontier: an assessment of Acacia mearnsii related park-community conflicts in the Golden Gate Highlands National Park, South Africa', Journal of Integrative Environmental Sciences, 13, 37-54, https://doi.org/10.1080/1943815X.2015.1130062.         [ Links ]

Nelufule, T., Robertson, M.F., Wilson, J.R.U., Faulkner, K.T, Sole, C. & Kumschick, S., 2020, 'The threats posed by the pet trade in alien terrestrial invertebrates in South Africa', Journal for Nature Conservation, 55, 125831, https://doi.org/10.1016/j.jnc.2020.125831.         [ Links ]

Ngorima, A. & Shackleton, C.M., 2019, 'Livelihood benefits and costs from an invasive alien tree (Acacia dealbata) to rural communities in the Eastern Cape, South Africa', Journal of Environmental Management, 229, 158-165, https://doi.org/10.1016/j.jenvman.2018.05.077.         [ Links ]

Novoa, A., Dehnen-Schmutz, K., Fried, J. & Vimercati, G., 2017, 'Does public awareness increase support for invasive species management? Promising evidence across taxa and landscape types', Biological Invasions, 19, 3691-3705, https://doi.org/10.1007/s10530-017-1592-0.         [ Links ]

Novoa, A., Shackleton, R., Canavan, S., Cybèle, C., Davies, S.J., Dehnen-Schmutz, K., Fried, J., Gaertner, M., Geerts, S., Griffiths, C.L., Kaplan, H., Kumschick, S., Le Maitre, D.C., Measey, G.J., Nunes, A.L., Richardson, D.M., Robinson, T.B., Touza, J. & Wilson, J.R.U., 2018, 'A framework for engaging stakeholders on the management of alien species', Journal of Environmental Management, 205, 286297, https://doi.org/10.1016/j.jenvman.2017.09.059.         [ Links ]

Nsikani, M.M., Van Wilgen, B.W. & Gaertner, M., 2018, 'Barriers to ecosystem restoration presented by soil legacy effects of invasive alien N₂-fixing woody species: implications for ecological restoration', Restoration Ecology, 26, 235-244, https://doi.org/10.1111/rec.12669.         [ Links ]

Ntshotsho, F., Forsyth, G., Le Maitre, D., Sitas, N. & Yapi, T., 2015, 'Two decades of managing invasive alien plants: exploring Working for Water success stories', CSIR Science Scope, 8, 100-101, https://journals.co.za/doi/pdf/10.10520/EJC179976.         [ Links ]

Nunez, M.A., August, T., Bacher, S., Galil, B.S., Hulme, F.E., Ikeda, T., McGeoch, M.A., Ordonez, A., Rahlao, S., Truong, T.R., Pauchard, A., Roy, H.E., Sankaran, K.V., Schwindt, E., Seebens, H., Sheppard, A.W., Stoett, F., Vandvik, V. & Meyerson, L.A., 2024, 'Including a diverse set of voices to address biological invasions', Trends in Ecology & Evolution, 39, 409-412, https://doi.org/10.1016/j.tree.2024.02.009.         [ Links ]

O'Connor, T. & Van Wilgen, B.W., 2020, 'The impact of invasive alien plants on rangelands in South Africa', in B.W. van Wilgen, J. Measey, D.M. Richardson, J.R. Wilson & T.A. Zengeya (eds), Biological invasions in South Africa, Springer, Cham, Switzerland, https://doi.org/10.1007/978-3-030-32394-3_16.         [ Links ]

Ogden, N.H., Wilson, J.R.U., Richardson, D.M., Hui, C., Davies, S.J., Kumschick, S., Le Roux, J.J., Measey, J., Saul, W.-C. & Fulliam, J.R.C., 2019, 'Emerging infectious diseases and biological invasions: a call for a One Health collaboration in science and management', Royal Society Open Science, 6, 15 (181577), https://doi.org/10.1098/rsos.181577.         [ Links ]

Faap, T., de Beer, Z.W., Migliorini, D., Nel, W.J. & Wingfield, M.J., 2018, 'The polyphagous shot hole borer (PSHB) and its fungal symbiont Fusarium euwallaceae: a new invasion in South Africa', Australasian Plant Pathology, 47, 231237, https://doi.org/10.1007/s13313-018-0545-0.         [ Links ]

Paini, D.R., Sheppard, A.W., Cook, D.C., De Barro, P.J., Worner, S.F. & Thomas, M.B., 2016, 'Global threat to agriculture from invasive species', Proceedings of the National Academy of Sciences of the United States of America, 113, 7575-7579, https://doi.org/10.1073/pnas.1602205113.         [ Links ]

Paterson, I.D., Klein, H., Muskett, F.C., Griffith, T.C., Mayonde, S., Mofokeng, K., Mnqeta, Z. & Venter, N., 2021, 'Biological Control of Cactaceae in South Africa', African Entomology, 29, 713-734, https://doi.org/10.4001/003.029.0713.         [ Links ]

Pinto, E.M., Vaz, A.S., Honrado, J.F., Roy, H.E., Pauchard, A., Stoett, F., Shackleton, R.T., Richardson, D.M. & Vicente, J.R., 2022, 'Folicy-oriented research in invasion science: trends, status, gaps, and lessons', BioScience, 72, 10741087, https://doi.org/10.1093/biosci/biac079.         [ Links ]

Potgieter, L.J., Cadotte, M.W., Roets, F. & Richardson, D.M., 2024, 'Monitoring urban biological invasions using citizen science: the polyphagous shot hole borer (Euwallacea for-nicatus)', Journal of Pest Science, 97, 2073-2085, https://doi.org/10.1007/s10340-024-01744-7.         [ Links ]

Pysek, F., Hulme, F.E., Simberloff, D., Bacher, S., Blackburn, T.M., Carlton, J.T., Dawson, W., Essl, F., Foxcroft, L.C., Genovesi, F., Jeschke, J.M., Kuhn, I., Pergl, J., Roy, H.E., Seebens, H., Van Kleunen, M., Vila, M., Wingfield, M.J. & Richardson, D.M., 2020, 'Scientists' warning on invasive alien species', Biological Reviews, 95, 1511-1534, https://doi.org/10.1111/brv.12627.         [ Links ]

Richardson, D.M., Boshoff, N., Davies, S.J. & Van Wilgen, B.W., 2020a, 'South Africa's Centre for Invasion Biology: an experiment in invasion science for society', in B.W. van Wilgen, J. Measey, D.M. Richardson, J.R. Wilson & T.A. Zengeya (eds), Biological invasions in South Africa, Springer, Cham, Switzerland, https://doi.org/10.1007/978-3-030-32394-3_30.         [ Links ]

Richardson, D.M., Foxcroft, L.C., Latombe, G., Le Maitre, D.C., Rouget, M. & Wilson, J.R., 2020b, 'The biogeography of South African terrestrial plant invasions', in B.W. van Wilgen, J. Measey, D.M. Richardson, J.R. Wilson & T.A. Zengeya (eds), Biological invasions in South Africa, Springer, Cham, Switzerland, https://doi.org/10.1007/978-3-030-32394-3_3.         [ Links ]

Riddin, T., Van Wyk, E. & Adams, J., 2016, 'The rise and fall of an invasive estuarine grass', South African Journal of Botany, 107, 74-79, https://doi.org/10.1016/j.sajb.2016.07.008.         [ Links ]

Robinson, T.B., Peters, K. & Brooker, B., 2020, 'Coastal invasions: the South African context', in B.W. van Wilgen, J. Measey, D.M. Richardson, J.R. Wilson & T.A. Zengeya (eds), Biological invasions in South Africa, Springer, Cham, Switzerland, https://doi.org/10.1007/978-3-030-32394-3_9.         [ Links ]

Rouget, M., Robertson, M.F., Wilson, J.R.U., Hui, C., Essl, F., Rentería, J.L. & Richardson, D.M., 2016, 'Invasion debt - quantifying future biological invasions', Diversity and Distributions, 22, 445-456, https://doi.org/10.1111/ddi.12408.         [ Links ]

Roy, H.E., Fauchard, A., Stoett, F.J., Renard Truong, T., Meyerson, L.A., Bacher, S., ... , Ziller, S.R., 2024, 'Curbing the major and growing threats from invasive alien species is urgent and achievable', Nature Ecology & Evolution, 8, 1216-1223, https://doi.org/10.1038/s41559-024-02412-w.         [ Links ]

Ruwanza, S. & Thondhlana, G., 2022, 'People's perceptions and uses of invasive plant Psidium guajava in Vhembe Biosphere Reserve, Limpopo Province of South Africa', Ecosystems and People, 18, 64-75, https://doi.org/10.1080/26395916.2021.2019834.         [ Links ]

Sadan, M., 2005, 'Gendered analysis of the Working for Water Programme: A case study of the Tsitsikamma Working for Water Project.', IDASA Occasional Paper, 25 pp.         [ Links ]

Schwindt, E., August, T.A., Vanderhoeven, S., McGeoch, M.A., Bacher, S., Galil, B.S., Genovesi, P., Hulme, P.E., Ikeda, T., Lenzner, B., Nuñez, M.A., Ordonez, A., Pauchard, A., Rahlao, S.J., Renard Truong, T., Roy, H.E., Sankaran, K.V., Seebens, H., Sheppard, A.W., Stoett, P., Vandvik, v., Wilson, J.R.U. & Meyerson, L.A., 2024, 'Overwhelming evidence galvanizes a global consensus on the need for action against Invasive Alien Species', Biological Invasions, 26, 621-626, https://doi.org/10.1007/s10530-023-03209-x.         [ Links ]

Seebens, H., Bacher, S., Blackburn, T.M., Capinha, C., Dawson, W., Dullinger, S., Genovesi, P., Hulme, P.E., Van Kleunen, M., Kuhn, I., Jeschke, J.M., Lenzner, B., Liebhold, A.M., Pattison, Z., Pergl, J., Pysek, P., Winter, M. & Essl, F., 2021, 'Projecting the continental accumulation of alien species through to 2050', Global Change Biology, 27, 970-982, https://doi.org/10.1111/gcb.15333.         [ Links ]

Seebens, H., Niamir, A., Essl, F., Garnett, S.T., Kumagai, J.A., Molnár, Z., Saeedi, H. & Meyerson, L.A., 2024, 'Biological invasions on Indigenous peoples' lands', Nature Sustainability, 7, 737-746, https://doi.org/10.1038/s41893-024-01361-3.         [ Links ]

Shackleton, C.M., McGarry, D., Fourie, S., Gambiza, J., Shackleton, S.E. & Fabricius, C., 2007, 'Assessing the effects of invasive alien species on rural livelihoods: case examples and a framework from South Africa', Human Ecology, 35, 113-127, https://doi.org/10.1007/s10745-006-9095-0.         [ Links ]

Shackleton, R.T., Le Maitre, D.C., Pasiecznik, N.M. & Richardson, D.M., 2014, 'Prosopis: a global assessment of the biogeography, benefits, impacts and management of one of the world's worst woody invasive plant taxa', AoB Plants, 6, plu027, https://doi.org/10.1093/aobpla/plu027.         [ Links ]

Shackleton, R.T., Le Maitre, D.C. & Richardson, D.M., 2015a, 'Stakeholder perceptions and practices regarding Prosopis (mesquite) invasions and management in South Africa', Ambio, 44, 569-581, https://doi.org/10.1007/s13280-014-0597-5.         [ Links ]

Shackleton, R.T., Le Maitre, D.C., Van Wilgen, B.W. & Richardson, D.M., 2015b, 'Use of non-timber forest products from invasive alien Prosopis species (mesquite) and native trees in South Africa: implications for management', Forest Ecosystems, 2, https://doi.org/10.1186/s40663-015-0040-9.         [ Links ]

Shackleton, R.T., Novoa, A., Shackleton, C.M. & Kull, C.A., 2020, 'The social dimensions of biological invasions in South Africa ', in B.W. van Wilgen, J. Measey, D.M. Richardson, J.R. Wilson & T.A. Zengeya (eds), Biological invasions in South Africa, Springer, Cham, Switzerland, https://doi.org/10.1007/978-3-030-32394-3_24.         [ Links ]

Shackleton, S., Kirby, D. & Gambiza, J., 2011, 'Invasive plants - friends or foes? Contribution of prickly pear (Opuntia ficus-indica) to livelihoods in Makana Municipality, Eastern Cape, South Africa', Development Southern Africa, 28, 177193, https://doi.org/10.1080/0376835X.2011.570065.         [ Links ]

Shivambu, N., Shivambu, T.C. & Downs, C.T., 2022, 'Survey of non-native small mammals traded in South Africa', African Journal of Ecology, 60, 456-466, https://doi.org/10.1111/aje.12999.         [ Links ]

Sileshi, G.W., Gebeyehu, S. & Mafongoya, P.L., 2019, 'The threat of alien invasive insect and mite species to food security in Africa and the need for a continent-wide response', Food Security, 11, 763-775, https://doi.org/10.1007/s12571-019-00930-1.         [ Links ]

Skowno, A., Poole, C., Raimondo, D., Sink, K., Van Deventer, H., Van Niekerk, L., Harris, L.R., SmithAdao, L.B., Tolley, K.A., Zengeya, T.A., Foden, W.B., Midgley, G.F. & Driver, A., 2019, 'National Biodiversity Assessment 2018: The status of South Africa's ecosystems and biodiversity. Synthesis Report', South African National Biodiversity Institute, Pretoria, an entity of the Department of Environmental Affairs.         [ Links ]

Stafford, L., Shemie, D., Kroeger, T., Baker, T., Apse, C., Turpie, J. & Forsythe, K., 2019, 'The Greater Cape Town Water Fund: assessing the return on investment for ecological infrastructure restoration', The Nature Conservancy, Cape Town, https://doi.org/10.13140/RG.2.2.23814.11844.         [ Links ]

Van der Colff, D., Kumschick, S., Foden, W., Raimondo, D., Botella, C., Von Staden, L. & Wilson, J.R.U., 2023, 'Drivers, predictors, and probabilities of plant extinctions in South Africa', Biodiversity and Conservation, 32, 43134336, https://doi.org/10.1007/s10531-023-02696-7.         [ Links ]

Van Helden, L., Van Helden, P.D. & Meiring, C., 2020, 'Pathogens of vertebrate animals as invasive species: insights from South Africa', in B.W. van Wilgen, J. Measey, D.M. Richardson, J.R. Wilson & T.A. Zengeya (eds), Biological invasions in South Africa, Springer, Cham, Switzerland, https://doi.org/10.1007/978-3-030-32394-3_10.         [ Links ]

Van Koppen, B., Schreiner, B. & Karar, E., 2011, 'Mainstreaming gender in water management in South Africa', in B. Schreiner & R. Hassan (eds), Transforming Water Management in South Africa: Designing and Implementing a New Policy Framework. Springer, Dordrecht, Netherlands, https://doi.org/10.1007/978-90-481-9367-7_10.         [ Links ]

Van Wilgen, B.W. & De Lange, W.J., 2011, 'The costs and benefits of biological control of invasive alien plants in South Africa', African Entomology, 19, 504-514, https://doi.org/10.4001/003.019.0228.         [ Links ]

Van Wilgen, N.J., Faulkner, K.T., Robinson, T.B., South, J., Beckett, H., Janion-Scheepers, C., Measey, J., Midgley, G.F. & Richardson, D.M., 2023b, 'Climate change and biological invasions in South Africa', in L. Ziska, (ed.), Invasive species and global climate change, CAB International, Wallingford, UK, https://doi.org/10.1079/9781800621459.0000.         [ Links ]

Van Wilgen, B.W., Faulkner, K.T., Wilson, J.R. & Theart, M., 2023a, 'Chapter 4: Interventions', in T.A. Zengeya & J.R. Wilson (eds), The status of biological invasions and their management in South Africa in 2022. South African National Biodiversity Institute, Kirstenbosch and DSI-NRF Centre of Excellence for Invasion Biology, Stellenbosch, pp. 47-73, https://doi.org/10.5281/zenodo.8217182.         [ Links ]

Van Wilgen, B.W., Le Maitre, D.C. & Cowling, R.M., 1998, 'Ecosystem services, efficiency, sustainability and equity: South Africa's Working for Water programme', Trends in Ecology and Evolution, 13, 378, https://doi.org/10.1016/S0169-5347(98)01434-7.         [ Links ]

Van Wilgen, B.W., Measey, G.J., Richardson, D.M., Wilson, J.R. & Zengeya, T. (eds), 2020a, Biological invasions in South Africa, Springer, Cham, Switzerland, https://doi.org/10.1007/978-3-030-32394-3.         [ Links ]

Van Wilgen, B.W., Measey, J., Richardson, D.M., Wilson, J.R. & Zengeya, T.A., 2020b, 'Biological invasions in South Africa: an overview', in B.W. van Wilgen, J. Measey, D.M. Richardson, J.R. Wilson & T.A. Zengeya (eds), Biological invasions in South Africa, Springer, Cham, Switzerland, https://doi.org/10.1007/978-3-030-32394-3_1.         [ Links ]

Van Wilgen, B.W. & Richardson, D.M., 2012, 'Three centuries of managing introduced conifers in South Africa: benefits, impacts, changing perceptions and conflict resolution', Journal of Environmental Management, 106, 56-68, https://doi.org/10.1016/j.jenvman.2012.03.052.         [ Links ]

Van Wilgen, B.W. & Wannenburgh, A., 2016, 'Co-facilitating invasive species control, water conservation and poverty relief: achievements and challenges in South Africa's Working for Water programme', Current Opinion in Environmental Sustainability, 19, 7-17, https://doi.org/10.1016/j.cosust.2015.08.012.         [ Links ]

Van Wilgen, B.W., Wannenburgh, A. & Wilson, J.R.U., 2022a, 'A review of two decades of government support for managing alien plant invasions in South Africa', Biological Conservation, 274, 109741, https://doi.org/10.1016/j.bio-con.2022.109741.         [ Links ]

Van Wilgen, B.W. & Wilson, J.R. (eds) 2018. The status of biological invasions and their management in South Africa in 2017: South African National Biodiversity Institute, Kirstenbosch and DST-NRF Centre of Excellence for Invasion Biology, Stellenbosch.         [ Links ]

Van Wilgen, B.W., Wilson, J.R., Wannenburgh, A. & Foxcroft, L.C., 2020c, 'The extent and effectiveness of alien plant control projects in South Africa', in B.W. van Wilgen, J. Measey, D.M. Richardson, J.R. Wilson & T.A. Zengeya (eds), Biological invasions in South Africa, Springer, Cham, Switzerland, https://doi.org/10.1007/978-3-030-32394-3_21.         [ Links ]

Van Wilgen, B.W., Zengeya, T.A. & Richardson, D.M., 2022b, 'A review of the impacts of biological invasions in South Africa', Biological Invasions, 24, 27-50, https://doi.org/10.1007/s10530-021-02623-3.         [ Links ]

Van Wilgen, N.J. & Herbst, M. (eds) 2017. Taking stock of parks in a changing world: the SANParks global environmental change assessment 2016, SANParks, Cape Town.         [ Links ]

Vezi, M.S., Downs, C.T. & Zengeya, T.A., 2024, 'Ornamental fish in the South African pet shop trade: potential risk to natural aquatic ecosystems', Biological Invasions, 26, 30313047, https://doi.org/10.1007/s10530-024-03349-8.         [ Links ]

Visser, V., Wilson, J.R.U., Canavan, K., Canavan, S., Fish, L., Maitre, D.L., Nänni, I., Mashau, C., O'Connor, T., Ivey, P, Kumschick, S. & Richardson, D.M., 2017, 'Grasses as invasive plants in South Africa revisited: patterns, pathways and management', Bothalia - African Biodiversity & Conservation, 47, a2169, https://doi.org/10.4102/abc.v47i2.2169.         [ Links ]

Weaver, K.N., Hill, M.P., Byrne, M.J. & Ivey, P., 2021, 'Efforts towards engaging communities to promote the benefits of biological control research and implementation in South Africa', African Entomology, 29, 1045-1059, https://doi.org/10.4001/003.029.1045.         [ Links ]

Weyl, O.L.F., Ellender, B.R., Wassermann, R.J., Truter, M., Dalu, T., Zengeya, T.A. & Smit, N.J., 2020, 'Alien freshwater fauna in South Africa', in B.W. van Wilgen, J. Measey, D.M. Richardson, J.R. Wilson & T.A. Zengeya (eds), Biological invasions in South Africa, Springer, Cham, Switzerland, https://doi.org/10.1007/978-3-030-32394-3_6.         [ Links ]

Weyl, O.L.F., Finlayson, B., Impson, N.D., Woodford, D.J. & Steinkjer, J., 2014, 'Threatened endemic fishes in South Africa's Cape Floristic Region: a new beginning for the Rondegat River', Fisheries, 39, 270-279, https://doi.org/10.1080/03632415.2014.914924.         [ Links ]

Wilkinson, M.D., Dumontier, M., Aalbersberg, I.J., Appleton, G., Axton, M., Baak, A., Blomberg, N., Boiten, J.-W., da Silva Santos, L.B., Bourne, P.E., Bouwman, J., Brookes, A.J., Clark, T., Crosas, M., Dillo, I., Dumon, O., Edmunds, S., Evelo, C.T., Finkers, R., Gonzalez-Beltran, A., Gray, A.J.G., Groth, P., Goble, C., Grethe, J.S., Heringa, J., 't Hoen, P.A.C., Hooft, R., Kuhn, T., Kok, R., Kok, J., Lusher, S.J., Martone, M.E., Mons, A., Packer, A.L., Persson, B., Rocca-Serra, P. Roos, M., Van Schaik, R., Sansone, S.-A., Schultes, E., Sengstag, T., Slater, T., Strawn, G., Swertz, M.A., Thompson, M., Van der Lei, J., Van Mulligen, E., Velterop, J., Waagmeester, A., Wittenburg, P., Wolstencroft, K., Zhao, J. & Mons, B., 2016, 'Comment: The FAIR Guiding Principles for scientific data management and stewardship', Scientific Data, 3, 9, https://doi.org/10.1038/sdata.2016.18.         [ Links ]

Wilson, J.R., 2024, 'A list of taxa currently and historically regulated under South Africa's National Environmental Management: Biodiversity Act, Alien & Invasive Species Regulations', v1.0 (20240331) edn., https://doi.org/10.5281/zenodo.10809766.         [ Links ]

Wilson, J.R., Faulkner, K.T., Fernández Winzer, L., McCulloch-Jones, E.J., Van Wilgen, B.W. & Zengeya, T.A., 2023, 'Chapter 6: Gaps', in T.A. Zengeya & J.R. Wilson (eds), The status of biological invasions and their management in South Africa in 2022. South African National Biodiversity Institute, Kirstenbosch and DSI-NRF Centre of Excellence for Invasion Biology, Stellenbosch, pp. 101-111, https://doi.org/10.5281/zenodo.8217182.         [ Links ]

Wilson, J.R., Foxcroft, L.C., Geerts, S., Hoffman, T.M., MacFadyen, S., Measey, J., Mills, A., Richardson, D.M., Robertson, M.P. & Van Wilgen, B.W., 2020, 'The role of environmental factors in promoting and limiting biological invasions in South Africa', in B.W. van Wilgen, J. Measey, D.M. Richardson, J.R. Wilson & T.A. Zengeya (eds.), Biological invasions in South Africa, Springer, Cham, Switzerland, https://doi.org/10.1007/978-3-030-32394-3_13.         [ Links ]

Wilson, J.R.U., Faulkner, K.T., Rahlao, S.J., Richardson, D.M., Zengeya, T.A. & Van Wilgen, B.W., 2018, 'Indicators for monitoring biological invasions at a national level', Journal of Applied Ecology, 55, 2612-2620, https://doi.org/10.1111/1365-2664.13251.         [ Links ]

Wilson, J.R.U., Gaertner, M., Richardson, D.M. & Van Wilgen, B.W., 2017, 'Contributions to the National Status Report on Biological Invasions in South Africa', Bothalia - African Biodiversity & Conservation, 47, a2207, https://doi.org/10.4102/abc.v47i2.2207.         [ Links ]

Wilson, J.R.U., Ivey, P., Manyama, P. & Nänni, I., 2013, 'A new national unit for invasive species detection, assessment and eradication planning', South African Journal of Science, 109, Art. #0111, https://doi.org/10.1590/sajs.2013/20120111.         [ Links ]

Wilson, J.R.U. & Kumschick, S., 2024, 'The regulation of alien species in South Africa', South African Journal of Science, 120, https://doi.org/10.17159/sajs.2024/17002.         [ Links ]

Wise, R.M., Van Wilgen, B.W. & Le Maitre, D.C., 2012, 'Costs, benefits and management options for an invasive alien tree species: The case of mesquite in the Northern Cape, South Africa', Journal of Arid Environments, 84, 8090, https://doi.org/10.1016/j.jaridenv.2012.03.001.         [ Links ]

Wondafrash, M., Wingfield, M.J., Wilson, J.R.U., Hurley, B..P, Slippers, B. & Paap, T., 2021, 'Botanical gardens as key resources and hazards for biosecurity', Biodiversity and Conservation, 30, 1929-1946, https://doi.org/10.1007/s10531-021-02180-0.         [ Links ]

WTO. 1998. Understanding the WTO Agreement on Sanitary and Phytosanitary Measures, World Trade Organization, viewed 4 July 2024, from https://www.wto.org/english/tratop_e/sps_e/spsund_e.htm.         [ Links ]

Yapi, T.S., O'Farrell, FiJ., Dziba, L.E. & Esler, K.J., 2018, 'Alien tree invasion into a South African montane grassland ecosystem: impact of Acacia species on rangeland condition and livestock carrying capacity', International Journal of Biodiversity Science, Ecosystem Services & Management, 14, 105-116, https://doi.org/10.1080/21513732.2018.1450291.         [ Links ]

Yessoufou, K., Ambani, A.E., Elansary, H.O., El-Sabrout, A.M. & Shokralla, S., 2022, 'Time, mediated through plant versatility, is a better predictor of medicinal status of alien plants', Diversity 14, 286, https://doi.org/10.3390/d14040286.         [ Links ]

Yessoufou, K., Ambani, A.E., Elansary, H.O. & Gaoue, O.G., 2021, 'Alien woody plants are more versatile than native, but both share similar therapeutic redundancy in South Africa', PLOS ONE, 16, e0260390, https://doi.org/10.1371/journal.pone.0260390.         [ Links ]

Zengeya, T., Ivey, P., Woodford, D.J., Weyl, O., Novoa, A., Shackleton, R., Richardson, D. & Van Wilgen, B., 2017, 'Managing conflict-generating invasive species in South Africa: Challenges and trade-offs', Bothalia - African Biodiversity & Conservation, 47, a2160, https://doi.org/10.4102/abc.v47i2.2160.         [ Links ]

Zengeya, T., McCulloch-Jones, E.J. & Van Wilgen, B.W., 2023a, 'Chapter 3: Sites', in T.A. Zengeya & J.R. Wilson (eds), The status of biological invasions and their management in South Africa in 2022, South African National Biodiversity Institute, Kirstenbosch and DSI-NRF Centre of Excellence for Invasion Biology, Stellenbosch, pp. 37-45, https://doi.org/10.5281/zenodo.8217182.         [ Links ]

Zengeya, T.A., Faulkner, K.T., Fernández Winzer, L., Kumschick, S., Miza, S., McCulloch-Jones, E.J. & Wilson, J.R., 2023b, 'Chapter 2: Species', in T.A. Zengeya & J.R. Wilson (eds), The status of biological invasions and their management in South Africa in 2022, South African National Biodiversity Institute, Kirstenbosch and DSI-NRF Centre of Excellence for Invasion Biology, Stellenbosch, pp. 27-35, https://doi.org/10.5281/zenodo.8217182.         [ Links ]

Zengeya, T.A. & Wilson, J.R. (eds) 2020. The status of biological invasions and their management in South Africa in 2019, South African National Biodiversity Institute, Kirstenbosch and DSI-NRF Centre of Excellence for Invasion Biology, Stellenbosch, https://doi.org/10.5281/zenodo.3947613.         [ Links ]

Zengeya, T.A. & Wilson, J.R. (eds) 2023. The status of biological invasions and their management in South Africa in 2022, South African National Biodiversity Institute, Kirstenbosch and DSI-NRF Centre of Excellence for Invasion Biology, Stellenbosch, https://doi.org/10.5281/zenodo.8217182.         [ Links ]

 

 

Correspondence:
John Wilson
E-mail: john.wilson2@gmail.com

Submitted: 30 August 2024
Accepted: 21 February 2025
Published: 6 November 2025

 

 

Supplementary Material

Available online: http://dx.doi.org/10.38201/abc.v55.9
Table S1. IPBES IAS Assessment experts and countries of affiliation
Table S2. The key message paragraphs from the IPBES IAS Assessment and the corresponding South African situation
Table S3. Objectives and actions for managing biological invasions with details of the South African situation
Table S4. Knowledge and data gaps identified in the IPBES IAS Assessment in the context of South Africa