The status of biological invasions and their management in South Africa in 2022 [SECOND DRAFT FOR PUBLIC COMMENT]

The Status of Biological Invasions and their Management in South Africa in 2022 [SECOND DRAFT FOR PUBLIC COMMENT] i Note to reader 1 We are inviting you to submit comments, corrections, and queries on this third status report on 2 biological invasions1. We have prepared a standard form for commenting that you can fill in if you 3 wish, but if you would prefer to send in your inputs in your own format, please indicate the page and 4 line numbers to which your comment refers. Many of the technical details (and data on which the 5 report is based like the list of alien species) are available in the appendices and supplementary 6 material (links available on the last page). Please also consider commenting on these. If you are in a 7 position to provide additional information, we would be very grateful, and will aim to ensure all 8 contributors are appropriately acknowledged. If you do not wish to be named, please let us know. We 9 would like as many people and organisations to make inputs as possible, so please pass the report on 10 to anyone you think might be able to contribute. We will capture all comments received during this 11 commenting period and track how they are responded to. A database of these comments and the 12 responses will be available on request once the report has been released. 13 Comments to be sent to: [email protected] By: 31 July 2023 14 Form for commenting: https://tinyurl.com/mr2mu6xz 15 This is a “second draft for public comment”. It presents the findings close to how they are intended to 16 be in the final report—there should only be minor changes and a few additional analyses, although 17 instances where additional analyses are planned for future reports are noted. 18 Thank you in advance for your comments, this report relies on the active participation of a wide range 19 of stakeholders, and we appreciate you taking the time to engage with us. 20 Yours sincerely, 21 Dr Tsungai Zengeya (on behalf of the third status report drafting team) 22 Kirstenbosch, 20 June 2023 23 1The previous status reports are available to download at http://iasreport.sanbi.org.za/ , links for on-line resources are available at end of this report. ii Citing this publication 24 For citations in the scientific literature: Zengeya, T.A. & Wilson, J.R. (Eds.), 2023. The status of 25 biological invasions and their management in South Africa in 2022 [SECOND DRAFT FOR PUBLIC 26 COMMENT]. South African National Biodiversity Institute, Kirstenbosch and DSI-NRF Centre of 27 Excellence for Invasion Biology, Stellenbosch. http://dx.doi.org/10.5281/zenodo.8037187 28 For citations in policy documents: SANBI and CIB 2023. The status of biological invasions and their 29 management in South Africa in 2022 [SECOND DRAFT FOR PUBLIC COMMENT]. South African National 30 Biodiversity Institute, Kirstenbosch and DSI-NRF Centre of Excellence for Invasion Biology, 31 Stellenbosch. http://dx.doi.org/10.5281/zenodo.8037187 32 ISBN: to be included in the final report 33 Authors 34 Lead editors: Tsungai A. Zengeya, John R. Wilson 35 Chapter lead authors: Katelyn T. Faulkner, Laura M. Fernández Winzer, Michelle Greve, Sabrina 36 Kumschick, Siyasanga Miza, Emily J. McCulloch-Jones, Peter C. le Roux, Marthán Theart, Brian W. van 37 Wilgen, John R. Wilson & Tsungai A. Zengeya 38 With contributions from: Julie A. Coetzee, Nicholas Cole, Whitney Engelbrecht, Martin P. Hill, Carol 39 Jacobs, Phetole Manyama, Themba Mnguni, Zachariah Mokganye, Debbie Muir, Wilma Nel, Trudy 40 Paap, Iain Paterson, Leoni Pretorius, Roger Price, Tamara B. Robinson, Aviwe Sifuba, Louise Stafford, 41 Andrew A. Turner, Anne Treasure, Karabo Wanjau, Andrew Wannenburgh, Mike J. Wingfield, Anton 42 Wolfaardt & Costas Zachariades 43 iii Table of Contents 44 Note to reader ......................................................................................................................................... i 45 Citing this publication ......................................................................................................................... ii 46 Authors ................................................................................................................................................ ii 47 Table of Contents .................................................................................................................................. iii 48 Foreword by the Minister of Environment, Forestry and Fisheries ..................................................... v 49 Preface by SANBI Board Chair ................................................................................................................ v 50 Preface by SANBI CEO ............................................................................................................................ v 51 List of acronyms...................................................................................................................................... v 52 Glossary ................................................................................................................................................. vi 53 Summary ................................................................................................................................................ xi 54 Trends in indicators .......................................................................................................................... xiii 55 Chapter 1: Introduction .......................................................................................................................... 1 56 1.1 The importance of biological invasions to South Africa ............................................................... 1 57 1.2 The mandate, purpose, and structure of the third status report ................................................. 1 58 1.3 Process for the compilation of the report .................................................................................... 3 59 1.4 Indicators ...................................................................................................................................... 7 60 1.5 Workflows and protocols .............................................................................................................. 8 61 1.6 Aspects of biological invasions that are not covered ................................................................... 8 62 Box 1.1 The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services 63 (IPBES) thematic assessment of invasive alien species and their control (IAS Assessment) .............. 9 64 Box 1.2 The Kunming-Montreal Global Biodiversity Framework (GBF) of the Convention on 65 Biological Diversity (CBD) .................................................................................................................... 9 66 Chapter 2: Pathways ............................................................................................................................ 11 67 Key findings for pathways ................................................................................................................. 11 68 Key gap for pathways ........................................................................................................................ 11 69 Indicators covered in the pathway chapter ...................................................................................... 12 70 2.1 Introduction pathway prominence ............................................................................................. 12 71 2.2 Introduction rates ....................................................................................................................... 13 72 2.3 Within-country pathway prominence ......................................................................................... 17 73 2.4 Within-country dispersal rates ................................................................................................... 17 74 Box 2.1. Work towards improving the pathways indicators ............................................................. 20 75 2.5 Trends in pathway indicators ...................................................................................................... 22 76 Chapter 3: Species ................................................................................................................................ 24 77 Key findings for species ..................................................................................................................... 24 78 Key gaps for species and sites ........................................................................................................... 24 79 Indicators covered in the species chapter ........................................................................................ 25 80 3.1 Number and status of alien species ............................................................................................ 25 81 3.2 Extent of alien species ................................................................................................................ 26 82 3.3 Abundance of alien species......................................................................................................... 27 83 3.4 Impact of aliens ........................................................................................................................... 27 84 Box 3.1 Native-alien populations ...................................................................................................... 29 85 3.5 Trend in species indicators.......................................................................................................... 31 86 Chapter 4: Sites..................................................................................................................................... 33 87 Key findings for sites ......................................................................................................................... 33 88 Indicators covered in the sites chapter ............................................................................................. 33 89 4.1 Alien species richness ................................................................................................................. 33 90 4.2 Relative invasive abundance ....................................................................................................... 36 91 4.3 Impact of invasions ..................................................................................................................... 38 92 Box 4.1 Estimating the costs of invasions to South Africa ................................................................ 38 93 iv 4.4 Trends in sites indicators ............................................................................................................ 40 94 Chapter 5: Interventions ...................................................................................................................... 41 95 Key findings regarding interventions ................................................................................................ 41 96 Key gaps regarding interventions ..................................................................................................... 42 97 Indicators covered in the interventions chapter .............................................................................. 43 98 5.1 Input—quality of the regulation framework .............................................................................. 43 99 5.2 Input—money spent ................................................................................................................... 47 100 5.3 Input—planning coverage ........................................................................................................... 52 101 5.4 Output—pathways treated ......................................................................................................... 57 102 5.5 Output—species treated ............................................................................................................. 58 103 5.6 Output—sites treated ................................................................................................................. 61 104 5.7 Outcome—effectiveness of pathway treatments ...................................................................... 62 105 5.8 Outcome—effectiveness of species treatments ......................................................................... 63 106 5.9 Outcome—effectiveness of site treatments ............................................................................... 64 107 Box 5.1 The regulation of invasive species used in commercial timber plantations ........................ 66 108 Box 5.2 The Greater Cape Town Water Fund ................................................................................... 68 109 Box 5.3 Successful biological control of water hyacinth on a eutrophic sub-tropical water-body .. 70 110 5.10 Trends in interventions indicators ............................................................................................ 71 111 Chapter 6: The status of biological invasions and their management in the Prince Edward Islands 75 112 Key findings for the PEIs.................................................................................................................... 75 113 Key gaps for the PEIs ......................................................................................................................... 76 114 Indicators covered in the PEIs chapter ............................................................................................. 76 115 6.1 Pathways ..................................................................................................................................... 76 116 6.2 Species ........................................................................................................................................ 81 117 6.3 Sites ............................................................................................................................................. 85 118 6.4 Interventions ............................................................................................................................... 88 119 6.5 Trends in indicators for the PEIs ................................................................................................. 95 120 Chapter 7: Gaps .................................................................................................................................. 100 121 Key gaps .......................................................................................................................................... 100 122 7.1 Process for identifying gaps ...................................................................................................... 100 123 7.2 Indicators—improving how invasions are measured and providing a link to other reports .... 101 124 7.3 Pathways—tracking invasions across South Africa ................................................................... 101 125 7.4 Species & Sites—mapping invasions in space and over time ................................................... 101 126 7.5 Species & Sites—determining the impacts and costs ............................................................... 102 127 7.6 Interventions—the need for an over-arching policy and strategy ........................................... 102 128 7.7 Interventions—measuring the effectiveness of interventions ................................................. 103 129 7.8 Suggestions for extensions to the scope of the report ............................................................. 103 130 Acknowledgements ............................................................................................................................ 105 131 References .......................................................................................................................................... 105 132 Links to supplementary material and appendices ............................................................................ 112 133 134 135 v Foreword by the Minister of Environment, Forestry and Fisheries 136 Preface by SANBI Board Chair 137 Preface by SANBI CEO 138 These elements will be added prior to the final report. 139 List of acronyms1 140 ASRARP Alien Species Risk Analysis Review Panel 141 A&IS Alien and Invasive Species as referred to either in the NEM:BA A&IS Regulations or the 142 NEM:BA A&IS Lists published under the regulations 143 CBD the Convention on Biological Diversity of the United Nations 144 CIB the Department of Science and Innovation-National Research Foundation Centre of 145 Excellence for Invasion Biology 146 DALRRD Department of Agriculture, Land Reform and Rural Development 147 DFFE Department of Forestry, Fisheries, and the Environment 148 EICAT Environmental Impact Classification for Alien Taxa 149 GBF the Kunming-Montreal Global Biodiversity Framework of the CBD 150 hmgc half-minute grid cell (used for mapping on the Prince Edward Islands) 151 NEM:BA the National Environmental Management: Biodiversity Act (Act No. 10 of 2004) 152 NEM:BA A&IS: see A&IS 153 NRM Natural Resource Management (a division of the DFFE) 154 PEIs the Prince Edward Islands 155 qdgc quarter-degree grid cell 156 RAC the Reference and Advisory Committee (of this third status report) 157 SANBI the South African National Biodiversity Institute 158 SAPIA the southern African Plant Invaders Atlas 159 SEICAT Socio-Economic Impact Classification for Alien Taxa 160 WfW Working for Water 161 ZAR South African Rands 162 163 164 1 These acronyms are used either in this report or in the supplementary material. For editorial conventions see supplementary material S1.1. vi Glossary1 165 Abundance (cf. distribution, extent): a measure of the number of individuals, coverage, or biomass of 166 an organism in a specified site. 167 Adaptive management: a structured, iterative process that includes the setting of goals, regular 168 monitoring of progress towards the achievement of those goals, and, based on the findings of the 169 monitoring, the adaptation of management to improve its effectiveness or a revision of the goals. 170 Adaptive management is useful where the outputs and outcomes of management are uncertain, and 171 where an approach of learning-by-doing can reduce uncertainty over time. 172 Alien species (cf. extralimital, native species): a species that is present in a site outside its natural 173 range as a result of human action that has enabled it to overcome biogeographic barriers. 174 Assessment: a critical evaluation of information. 175 Benefit: cost ratio: see returns on investment 176 Biodiversity: the variability among living organisms from all sources including terrestrial, marine, and 177 other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity 178 within species, between species and of ecosystems. 179 Biological invasions: the phenomenon of, and suite of processes that are involved in determining, the 180 transport of organisms to sites outside their native range by human activities and the fate of the 181 organisms in their new ranges. 182 Biological control (syn. biocontrol): the use of specimens of one species for the purpose of preying 183 on, parasitizing on, damaging, killing, suppressing or controlling a specimen of another species. 184 Biocontrol: see Biological control. 185 Biome: a large naturally occurring community of plants and animals that have common characteristics 186 in similar physical environments, e.g., desert or forest. 187 Biosecurity: measures that are taken to stop the introduction or dispersal of organisms harmful to 188 human, animal, or plant life. 189 Contested species: alien species for which there is dispute about the appropriate (if any) regulatory 190 listing. Also referred to as conflict-generating species. Such species have in some cases been listed as 191 category 2 under the NEM:BA A&IS Regulations, whereby a permit can be issued to stakeholders to 192 conduct otherwise illegal activities with the listed alien species. The contestation may thereby be 193 resolved. 194 Compliance: The action or fact of complying with instructions, in this second report such instructions 195 primarily refer to the provisions of NEM:BA. 196 Compliance notice (also pre-compliance notice): an official document served by an environmental 197 management inspector on a person when there are reasonable grounds for believing that that person 198 has not complied with a provision of the law or with a term or condition of a permit, authorisation or 199 other instrument issued in terms of such law. A pre-compliance notice is a written notice of intention 200 1These definitions are based on those in the second report, Richardson et al. (2010), Wilson et al. (2017), and van Wilgen et al (2020a) with consideration of definitions given in relevant South African and international legislation, specifically the NEM:BA and its A&IS Regulations, and the CBD ( https://www.cbd.int/invasive/terms.shtml). These cover terms used in this third report and in the supplementary material to the third report. For editorial conventions see supplementary material S1.1. vii to issue a compliance notice, which precedes the issuing of a compliance notice and invites the person 201 to whom it has been issued to make representations to the environmental management inspector. 202 Containment: the goal of preventing or reducing the spread of invasive species. 203 Contaminant: the accidental introduction of an alien species with an intentionally transported 204 commodity with which the organism has a specific, natural association. 205 Control: any action taken to prevent the recurrence, re-establishment, re-growth, multiplication, 206 propagation, regeneration or spreading of an alien species. 207 Conviction: a verdict of guilty issued by a competent court following the prosecution of a person 208 suspected of having committed a criminal offence. 209 Corridor: the natural spread of an alien species into a new region through a human-constructed 210 transport infrastructure that connects previously unconnected regions, and in the absence of which 211 dispersal would not have been possible. 212 Directive (also pre-directive): an official document served by an environmental management 213 inspector on a person when such person is: a) a permit holder and is suspected of not complying with 214 the conditions under which a permit has been issued or not taking all the required steps to prevent or 215 minimise harm to biodiversity by the alien species to which the permit relates; or b) a landowner and 216 is suspected of not fulfilling their duty of care in relation to listed alien species on their land. A directive 217 directs a person to take steps to remedy harm caused to biodiversity caused by such person’s non-218 compliance or failure to fulfil the landowner’s duty of care. A pre-directive is a written notice of 219 intention to issue a directive, which precedes the issuing of a directive and invites the person to whom 220 it is issued to make representations to the environmental management inspector. 221 Dispersal (syn. spread): movement of organisms within a defined site that is facilitated either 222 intentionally or accidentally by humans, or that occurs naturally. 223 Distribution: the extent and abundance of a species over a given site. 224 Eradication: the complete removal of all individuals and propagules of a population of an alien species 225 from a particular site to which there is a negligible likelihood of reinvasion. 226 Escape (cf. release): the spread of an alien species that was intentionally introduced and kept in 227 captivity or cultivation to sites outside of captivity or cultivation. Includes both natural spread and the 228 accidental or intentional illegal human-mediated dispersal of live organisms from the site of captivity 229 or cultivation. 230 Established: see naturalised. 231 Extent (cf. abundance, distribution): the broad-scale area over which an organism occurs. The spatial 232 scale over which extent is measured needs to be specified. The occupancy of sites at a fine-spatial 233 scale is often equivalent to the abundance. 234 Extirpation (cf. eradication): the result of a control operation whereby all individuals in a population 235 are removed. Other populations might be close by or pathways of introduction and dispersal are still 236 operating such that the probability of re-invasion is probable or not known. 237 Extralimital (cf. alien species, native species): a native species that has been introduced by humans 238 to a part of South Africa that is outside of the species’ native distribution range. It does not include 239 native species that have extended their distribution by natural dispersal. 240 Impact: the effect of an alien species on the physical, chemical, and biological environment. It can 241 include both negative and positive effects. 242 viii Incursion: an isolated population of a pest, weed, or alien species, that usually has a limited spatial 243 extent and has been recently detected at a site. In general, the management of incursions is referred 244 to as incursion response. 245 Indicator: a set of measurements that give specific information about the state of something. 246 Indigenous species: see Native species. 247 Interventions: the full variety of actions taken in response to biological invasions, including direct 248 actions, i.e., control, and indirect actions like monitoring, regulation, and research. 249 Introduced: see Introduction. 250 Introduction: the movement of an alien species (either accidentally, intentionally and legally, or 251 intentionally and illegally) by human activity, to a region outside its native range. Introductions can 252 also refer to species which were introduced to one country by humans and spread naturally to 253 neighbouring countries. In the context of introductions, the term ‘accidental’ is preferred to the 254 synonymous term ‘unintentional’. 255 Invasion: see Biological invasions. 256 Invasion debt: the potential increase in biological invasions at a site over a particular time frame in 257 the absence of any interventions (Rouget et al., 2016). It is composed of the number of new species 258 that will be introduced (introduction debt), the number of species that will become invasive (species-259 based invasion debt); the increase in area affected by invasions (area-based invasion debt); and the 260 increase in the negative impacts caused by introduced species (impact-based invasion debt). 261 Invasive alien species: see Invasive species. 262 Invasive species: Alien species that sustain self-replacing populations over several life cycles, produce 263 reproductive offspring, often in very large numbers at considerable distances from the parent and/or 264 site of introduction, and have the potential to spread over long distances. 265 Invasiveness: the features of an alien organism, such as their life-history traits and modes of 266 reproduction, that define their capacity to become an invasive species. 267 Listed alien species: species which are listed under the NEM:BA A&IS Regulations either as ‘listed 268 invasive species’ (which are intended to only include alien species that are present in South Africa) or 269 ‘prohibited alien species’ (which are intended to only be species that are absent from South Africa). 270 Monitoring: a systematic process of collecting and analysing information to track progress towards 271 reaching stated goals, that facilitates the assessment of the efficacy of interventions. 272 Native-alien populations: a population of a taxon that is native to a part of South Africa, but that was 273 founded by individuals moved by direct human agency, over a biogeographical barrier, to an area 274 beyond the species’ native range (i.e., it can be considered a biological invasions) (see Box 3.1). 275 Native species (syn. indigenous species, cf. alien species, extralimital): species that are found within 276 their natural range where they have evolved without human intervention (intentional or accidental). 277 Also includes species that have expanded their range as a result of human modification of the 278 environment that does not directly impact dispersal (e.g., populations are still considered native if 279 they result from an increase in range as a result of watered gardens, but are considered alien if they 280 result from an increase in range as a result of spread along human-created corridors linking previously 281 separate biogeographic regions). 282 Naturalised (syn. established): Alien species that sustain self-replacing populations for several life 283 cycles or over a given period of time without direct intervention by people, or despite human 284 intervention. 285 1 Chapter 1: Introduction 410 Authors: John R. Wilson, Tsungai A. Zengeya 411 1.1 The importance of biological invasions to South Africa 412 Biological invasions are amongst the leading causes of global change—they have had profound 413 negative impacts on people and nature for centuries; are currently a significant drain on South Africa’s 414 sustainable development and are negatively impacting native biodiversity; and pose a major threat to 415 both the quality of life of future generations and the globally unique flora and fauna that are an 416 integral part of this country (Pyšek et al. 2020, van Wilgen et al. 2020). The problem is complicated 417 and set to grow (Chapters 2 and 6). Invasive species come from many different taxa, invade different 418 habitats, and cause various types of impacts sometimes in ways which are not yet fully understood 419 but that will have profound effects on the ability of ecosystems to deliver services to people (Chapters 420 3, 4, and 6; van Wilgen et al. 2020). 421 Thankfully, however, significant progress has been made in reducing impacts and preventing new 422 invasions (Chapter 5). Targeted interventions can be highly cost-effective, and so, while interventions 423 can be complicated and costly, by working together as a society we can protect our biodiversity and 424 natural capital from biological invasions. The nature of the impacts and the types of responses needed 425 means that biological invasions are a significant cross-cutting issue for South Africa that is managed 426 by a range of stakeholders using a variety of approaches. 427 1.2 The mandate, purpose, and structure of the third status report 428 The issue of biological invasions has received significant recent global attention in particular with the 429 production and upcoming release in October 2023 of the Intergovernmental Science-Policy Platform 430 on Biodiversity and Ecosystem Services (IPBES)’s “Thematic assessment of invasive alien species and 431 their control” (Box 1.1); and the Kunming-Montreal Global Biodiversity Framework (GBF) that was 432 agreed under the Convention on Biological Diversity (CBD) in December 2022 (Box 1.2). This third 433 status report sits firmly within this context, but the specific mandate for the status report originally 434 arose from section 11 of the National Environmental Management: Biodiversity Act, Alien and Invasive 435 Species Regulations (NEM:BA A&IS Regulations) that were published 1 August 2014 and promulgated 436 in October 2014. Revised regulations were published 18 September 2020 and promulgated 1 March 437 2021, with section 13 stating: 438 (1) The Institute1 or a body designated by the Institute must, for the purpose of reporting as 439 contemplated in section 11(1)(a)(iii) of the Act, submit a report on the status of listed 440 1 The South African National Biodiversity Institute (SANBI) 2 invasive species to the Minister within three years of the date on which these regulations 441 come into effect, and at least every three years thereafter1. 442 (2) A report contemplated in sub-regulation (1) must contain a summary and assessment of— 443 (a) the status of listed invasive species and other species that have been subjected to a risk 444 assessment; and 445 (b) the effectiveness of these regulations and control measures based inter alia on 446 information from— 447 (i) notifications received from owners of land regarding listed invasive species 448 occurring on their land; 449 (ii) permits issued for listed invasive species; 450 (iii) Invasive Species Monitoring, Control and Eradication Plans received from organs 451 of state and management authorities of protected areas; and 452 (iv) emergency interventions and enforcement actions involving listed invasive 453 species. 454 (3) In preparing a report contemplated in sub-regulation (1), the Institute must carry out the 455 research and monitoring necessary to identify the matters contemplated in sub-regulation 456 (2). 457 458 More broadly, however, the status report aims to strengthen the links between basic research, policy, 459 and management, by providing support to decision makers that is policy relevant but not policy 460 prescriptive (Figure S.1). 461 The first report was produced in 2017 and released in 2018, and the second produced in 2020 and 462 released in 2021. Both were structured around an indicator framework that explicitly considers 463 biological invasions in terms of pathways, species, sites, and interventions (with indicators on 464 interventions divided into those considering inputs, outputs, and outcomes, Figure 1.1). This indicator 465 framework provides a transparent and objective method for the establishment of a baseline against 466 which to assess trends, set realistic management targets, and for highlighting important gaps in the 467 evidence needed to support decision-making. This third report outlines trends over the past three 468 years for the four headline indicators and for the 20 indicators tracking pathways, species, sites, and 469 interventions. It takes time to compile, revise, and produce these reports. Therefore a cut-off date is 470 needed, after which no new data are considered. This third report is thus entitled ‘The status of 471 biological invasions and their management in South Africa in 2022’, as it reports on the status up to 472 the end of 2022, although it is due to be finalised by October 2023 and released early in 2024. 473 The report is comprised of chapters based on the framework (i.e., on pathways, species, sites, and 474 interventions). Each chapter starts with a summary of the state of the indicators, and then a discussion 475 of key changes to the indicators and recent noteworthy events, with important case-studies in the 476 form of text boxes. In addition, for this report, a chapter-length case study is provided on “The Status 477 of Biological Invasions and their Management in the Prince Edward Islands”. The Prince Edward Islands 478 1 So technically this report is due March 2024, although in keeping with a three year cycle, the report was produced by October 2023. 3 (Marion Island and Prince Edward Island) lie in the Southern Ocean, 1400 km from continental South 479 Africa, and are distinct from the mainland both in terms of the nature of biological invasions and how 480 they are managed. A final chapter evaluates the degree to which gaps identified in the previous 481 reports have been filled, looks at additional key gaps that need to be addressed in future reports, and 482 identifies recommendations relevant for how South Africa understands and manages biological 483 invasions. Much of the detail underlying the production of the report is contained within the 484 appendices and supplementary material available on-line (links to them are on the last page of the 485 report). 486 A focus of this report is to produce work-flows (see Section 1.5) and ensure data are FAIR1 and tidy 487 (see Section S1.4) in line with international best practice (IPBES 2018). In so doing, the report process 488 should be more sustainable in that the processes used are documented and can be repeated. The 489 longer-term plan is to develop an on-line resource with indicator values updated as soon as new 490 information becomes available (i.e., a dashboard) that can be used to produce reports on demand, 491 and form the basis both of semi-automated annual reports and less frequent comprehensive reports 492 (see Section S.1.2, noting that such plans will need to be compatible with regulatory requirements—493 currently triennial reports are mandated). The intention of this report is thus to provide an update to 494 the second report, and focus on the process, recognising that all identified data sources have not yet 495 been incorporated (see Appendix 1 for data sources used, and those that will be incorporated in 496 future). 497 1.3 Process for the compilation of the report2 498 The process was broadly similar to the first two reports (Figure 1.1), with largely the same team, 499 consisting of the South African National Biodiversity Institute as the lead institute, the Centre for 500 Invasion Biology as a collaborating partner, and various managers, researchers, private individuals, 501 and institutions providing information and comments on draft reports. 502 Review of release of the 2nd report and essential work-flows identified: The SANBI-CIB drafting team 503 reflected on the report launch and how the report was received, and in particular identified the need 504 for closer engagement with affected government departments. In particular, it was noted that by 505 providing an opportunity to evaluate the findings and develop appropriate responses ahead of the 506 report launch, affected agencies would be in a better position to respond to and uptake the findings. 507 1 Findable, Accessible, Interoperable, and Reusable: www.go-fair.org/ 2 The process includes future planned events written as if they have already occurred. These will be updated as the report develops but are included here for completeness and in the tense they will be in the final report. 4 The drafting team also identified essential work-flows for the production of the report that needed to 508 be set up during this report cycle (Section 1.5). 509 Appoint a reference and advisory committee (RAC): a RAC was established to provide oversight of the 510 process and review documents produced. The first meeting of the RAC was on 22 February 2022 at 511 which a proposed table of contents was approved. A draft of the report was sent to the RAC on 9 512 September 2022, and discussed at the second meeting of the RAC on 28 September 2022. The report 513 was revised and set out for public comment on 20 December 2022. The second draft for public 514 comment was sent to the RAC at the same time as it was made public, and a meeting held 26 June 515 2023. The Chair of the RAC also reviewed how the comments received during all rounds of review 516 were addressed, i.e., acted in a review editor role. Finally, the RAC provided advice both in terms of 517 the public release of the report, and on reflecting on the process. 518 Collate and review available information: Information was incorporated into the report primarily from 519 published literature and unpublished information provided by stakeholders. Information contained in 520 the report is based on data available to the report writing team as of the end of December 2022 (see 521 Supplementary Material for each chapter and Appendix 1). 522 Stakeholder engagement: During report production, stakeholder engagement was an on-going 523 process linked to the other activities. Initially the drafting team engaged directly with specialist 524 contributors to obtain information that was not readily accessible and identified stakeholders to be 525 contacted for input and review. Contributors were identified initially based on those identified 526 previously, and those who provided comments were asked for updates. New potential contributors 527 were contacted on an ad hoc basis as information became available and in response to the public 528 consultation. Contributors came from academic institutions; research institutes and science councils; 529 national, provincial, and local government departments; and from private individuals whom were 530 interested and affected. Contributions from the identified stakeholders were in the form of data 531 provision and commenting on drafts. 532 The report process is on-going. There are information sources available that, given constraints, could 533 not be fully incorporated in this third report (in particular see Table S3.1 for information sources that 534 need to be incorporated into the species list). In cases where information was believed to be available 535 but was not forthcoming, the lack of information is flagged either in the report or in the supplementary 536 material. Finally, some information is simply not available as it has either not been gathered or 537 appropriately curated. For a discussion on gaps see Chapter 7. 538 5 539 Figure 1.1 Key steps in the production of the report ‘the Status of Biological Invasions and their 540 Management in South Africa in 2022’. The Minister is the South African Minister of Forestry, Fisheries 541 and the Environment; the RAC is the research and advisory committee; and SANBI is the South African 542 National Biodiversity Institute. 543 Status report team review the release of the 2 nd report and identify workflows needed for the 3 rd report (Jun–Dec 2021) Collate and review available information Identify and engage specialist contributors Reference and advisory committee Assign values to indicators Revised draft for public comment (Dec 2022–Feb 2023 Stakeholder engagement Identify stakeholders Stakeholder review (Dec 2022–Feb 2023) Revise draft after public comments (Feb–Jun 2023) Final revisions and report production (Jul–Aug 2023) Media enquiries Submit to SANBI Board (Sep 2023) Submit to Minister (Oct 2023) Public release (Jan 2024) Reflect on the process Draft table of contents (Feb 2022) Meeting (22 Feb 2022) Appoint a RAC (Jan 2022) Conference and workshop presentations Review draft Review of revised draft, and response to comments received Meeting (Dec or Jan 2023) 2 nd round of stakeholder review & additional expert review (Jun–Jul 2023) Check responses to comments received 2 nd status report finalised (2 Nov 2020) 2 nd status report launched (28 May 2021) Engage with government on their response to key findings (Oct–Dec 2023) Produce draft report (Sep 2022) Meeting (28 Sep 2022) Meeting (26 Jun 2023) Revised draft for public comment (Jun–Jul 2023) 6 Review of draft reports: A draft was completed in September 2022 and sent to the RAC for internal 544 review. This was then discussed at a meeting of the RAC on 28 September, revised, and sent out for 545 public review by experts and stakeholders for a period of 10 weeks (20 December 2022–28 February 546 2022). The request for review was submitted to a South African list server on biological invasions 547 ([email protected]), heads of relevant national and provincial government departments, 548 heads of relevant academic departments and institutions, and professional societies and forums 549 (including the Royal Society of South Africa; the Akademie vir Wetenskap en Kuns; the Zoological, 550 Entomological, and Botanical Societies; Birdlife South Africa; and the Wildlife and Environment Society 551 of South Africa). A copy of the first draft for public comment was attached to the formal notice and 552 was available for download online (http://dx.doi.org/10.5281/zenodo.7414804). 553 In June 2023, the next draft of the report was produced and sent for public comment for 6 weeks using 554 the same links as previously (20 June 2023–31 July 2023). In addition, the report was sent to two 555 independent experts from South Africa, one international expert, and members of the RAC. A copy of 556 the second draft for public comment was attached to the formal notice and was available for 557 download online (http://dx.doi.org/10.5281/zenodo.8037187). 558 During the first round of external public review, comments were received from 19 sources, 559 representing 10 institutions including the DFFE and the DWS. During the second round of external 560 public review, comments were received from XX sources, representing YY institutions…1. 561 All feedback was recorded and the comments responded to in line with international best practice 562 (IPBES 2018). The inputs and responses to the requests for review, were documented and are available 563 for scrutiny from SANBI on request. 564 Produce and release the final report: Following the comments from the final round of review that 565 closed 31 July 2023, the report was edited, and a complete version sent in August 2023 to the SANBI 566 Graphics team for editing, layout, design, and printing. A fully laid out version of the report was then 567 submitted to the SANBI Board in September 2023 for their consideration. After board approval, the 568 SANBI CEO submitted the report to the Minister of Forestry, Fisheries and the Environment. At the 569 same time a copy of the report was submitted to the DFFE and the DALRRD as the key receivers of the 570 report. This provided the departments with an opportunity to prepare for responding to media 571 enquiries or public concerns raised and to seek clarification from the report drafting team as needed, 572 noting that no changes could be made to the report during this period. To maximise publicity and 573 media uptake of the report, the report is intended to be released to the public in early January 2024 574 1the number of people and institutions commenting to be added later, potentially combined if there is a large degee of overlap. 7 in time for the fresh news cycle of the year. As with previous reports, information will be included in 575 the South African State of the Environment Report process (http://soer.environment.gov.za/soer/). 576 Reflect on the process: After the public release of the report the status report team will convene a 577 meeting with key stakeholders (including members of the RAC) to reflect on the process used to 578 compile the report and to identify areas of improvement for subsequent reports (see Chapter 7). 579 1.4 Indicators 580 This report is structured around the 20 indicators and 4 high-level indicators outlined in Wilson et al. 581 (2018) (Figure 1.2) and adheres broadly to the published indicator factsheets1. However, there have 582 been slight updates and corrections to how some things were scored, and so the indicators should be 583 read in concert with the metadata to the species list and other workflows, with the more recent 584 documents taking precedence. Specifically, the technical details on scoring the indicators and the high-585 level indicators are available in the supplementary material. Fully revised and updated indicator 586 factsheets will be provided together with the next report. 587 588 Figure 1.2 Indicators used in the report (based on Wilson et al. 2018). 589 Notably, the baselines proposed in previous reports needed to be revised in some instances (e.g., due 590 to errors in the original values). This means that it is not always appropriate to compare values 591 between the reports, and in some cases the report calculated the values that should have been in 592 previous reports. Changes over time from these revised baselines are presented and discussed in this 593 1The indicator factsheets can be downloaded at, https://tinyurl.com/5n6fbymh 5. Number and status of alien species 6. Extent of alien species 7. Abundance of alien species SPECIES SITES 9. Alien species richness 10. Relative invasive abundance PATHWAYS 1. Introduction pathway prominence 3. Within-country pathway prominence INTERVENTIONS 2. Introduction rates 4. Within-country dispersal rates 18. Effectiveness of pathway treatments OUTCOMES 8. Impact of alien species 11. Impact of invasions 19. Effectiveness of species treatments 20. Effectiveness of site treatments OUTPUTS 16. Species treated 17. Sites treated INPUTS 14. Planning coverage HIGH LEVEL A. Rate of unregulated introduction of new species HIGH LEVEL B. Number of invasive species that have major impacts HIGH LEVEL C. Extent of area that suffers major impacts from invasions HIGH LEVEL D. Level of success in managing invasions 15. Pathways treated 13. Money spent 12. Quality of regulatory framework 8 report, and differences in the calculation methods used between the reports are noted in the 594 supplementary material. 595 1.5 Workflows and protocols 596 Given the need for a repeatable, transparent process, various workflows were identified and 597 constructed to outline how the report was put together and to inform future report production. These 598 are discussed in the relevant chapters and presented in full in Appendix 4. They are listed here for 599 reference: 600 • Introduction pathway prominence; 601 • Tracking data sources; 602 • Adding alien taxa and enrichment data to the species list; 603 • Updating the permit database; 604 • Money spent; and 605 • Alien taxa impact assessment. 606 Mirroring the above workflows, a workflow was also established for sourcing, capturing, and reporting 607 information for the Prince Edward Islands (Chapter 6). For future report workflows are planned for: 608 Processing occurrence records to give species richness and abundance estimates at different spatial 609 units; Impacts on key ecosystem services; Regulatory processes (beyond just the permit database); 610 Evaluating control plans and their implementation; and Compliance and inspections and court cases 611 Some of these workflows required specific protocols where the intention is for these to be applied 612 outwith the report. For example, a protocol has been set up to classify native-alien populations 613 (Nelufule et al. 2022, Box 3.1). 614 1.6 Aspects of biological invasions that are not covered 615 The aspects not covered in this report are largely the same as those not covered in previous reports 616 (see supplementary material S1.6). COVID-19 has had profound impacts on the lives of South Africans. 617 However, in the absence of an explicit analysis as to how the pandemic and the response by the 618 government (e.g., the national lockdowns) directly affected biological invasions, the impact of COVID-619 19 is not explicitly considered here, except where there were palpable impacts on the indicators (e.g., 620 the significant drop in trade and travel affected the indicators on introduction pathway prominence 621 and within-country pathway prominence, cf. Figure S2.19). 622 623 9 Box 1.1 The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services 624 (IPBES) thematic assessment of invasive alien species and their control (IAS Assessment) 625 The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) is an 626 independent intergovernmental body established by States to strengthen the science-policy interface 627 for biodiversity and ecosystem services for the conservation and sustainable use of biodiversity, long-628 term human well-being and sustainable development. In 2018, a global IAS Assessment was initiated 629 and is to be presented for approval by the parties to IPBES as part of the 10th IPBES Plenary (28 August–630 2 September 2023). The aim of the IAS Assessment is “to critically evaluate available evidence on the 631 severity of the threat of biological invasions to underpin potential options for decision-making.” The 632 report is due to be released to the public later in 2023 (~October 2023). As such it was not possible to 633 include the findings in this third report, but the report will form a core source for the development of 634 the next comprehensive report. For details see https://ipbes.net/invasive-alien-species-assessment 635 636 Box 1.2 The Kunming-Montreal Global Biodiversity Framework (GBF) of the Convention on 637 Biological Diversity (CBD) 638 One purpose of this report is to facilitate South Africa’s reporting to international bodies on biological 639 invasions, including to the CBD. As such the aim is to align this report with inter-governmental 640 reporting processes and indicators. The CBD at a meeting in December 2022 agreed to the Kunming-641 Montreal Global Biodiversity Framework (GBF). Target 6 of the GBF focusses on biological invasions: 642 Eliminate, minimize, reduce and or mitigate the impacts of invasive alien species on biodiversity and 643 ecosystem services by identifying and managing pathways of the introduction of alien species, 644 preventing the introduction and establishment of priority invasive alien species, reducing the rates of 645 introduction and establishment of other known or potential invasive alien species by at least 50 per 646 cent, by 2030, eradicating or controlling invasive alien species especially in priority sites, such as 647 islands. 648 Given the timing of the finalisation of the target, this report does not explicitly address these elements, 649 but notably the structure of the target is broadly addressed by the indicator framework [e.g., the focus 650 on pathways, species, and sites; cf. Essl et al. (2020)]. The next comprehensive report will focus on 651 specifically reporting on the target. The indicators to be used to track progress against target 6 are still 652 to be finalised. Nonetheless significant progress has been made. For example, the working group 653 sTwist “Theory and Workflows for Alien and Invasive Species Tracking” 654 (https://www.idiv.de/en/stwist.html) has proposed three indicators (McGeoch et al. 2021). Rate of 655 10 Invasive Alien Species Spread provides modelled rates of ongoing introductions of species based on 656 invasion discovery and reporting. Impact Risk estimates invasive species impacts on the environment 657 in space and time and provides a basis for nationally targeted prioritization of where best to invest in 658 management efforts; and Status Information on invasive alien species tracks improvement in the 659 essential dimensions of information needed to guide relevant policy and data collection and in support 660 of assessing invasive species spread and impact. Though each of these needs to be peer-reviewed. The 661 applicability of these indicators to the South Africa context, and how they relate to the indicator 662 framework used in this report will be a focus of future reports. 663 664 17 2.3 Within-country pathway prominence 802 Within-country pathway prominence considers the opportunities available for the movement of 803 organisms within the country, and does not take into account how many dispersal events these 804 opportunities result in. 805 As in previous reports, data for within-country pathway prominence were not available for most 806 pathways, and so the indicator could not be populated. However, there were some apparent general 807 trends, and recent research has provided information on the introduction opportunities provided by 808 some dispersal pathways. As discussed above, opportunities for introductions to the country were 809 impacted by the controls put in place to reduce the spread of COVID-19. These controls also impacted 810 the opportunities available, through some pathways, for dispersal within the country. For example, 811 the decline in the number of domestic aircraft arrivals (a decline of ~67%) in the 2020/2021 financial 812 year (Figure S2.19) was similar to that for international and regional aircraft arrivals (a decline of 74%). 813 However, there are a wide range of pathways that create dispersal opportunities within the country, 814 and it is likely that not all were impacted to this extent. Furthermore, these opportunities are returning 815 to pre-pandemic levels (for an example see Figure S2.19). Recent research has highlighted the large 816 role that wildlife ranching (Taylor et al. 2021), medicinal plant trade and the pet trade (Shivambu et 817 al. 2022a) are playing in moving organisms around the country. A survey of pet shops indicated that 818 the sources of pets in the trade are often local, with at least 40% of the respondents obtaining their 819 animals from local sources such as animal rescues and other pet shops, or breeding them themselves 820 (Shivambu et al. 2022a). Many of the alien plants in the medicinal plant trade are also sourced locally 821 and moved around the country for this purpose. A survey of the trade in Gauteng and KwaZulu-Natal 822 showed that 41% of the plants for sale were harvested in southern Africa, with most of these plants 823 being sourced in KwaZulu-Natal (Williams et al. 2021b). Alien plants have been incorporated into local 824 pharmacopoeias not because they are used to treat different ailments than native taxa, but as they 825 are versatile in terms of their uses – they can be used for many purposes besides medicine – and many 826 have been in the country for a long time (Yessoufou et al. 2021, 2022). 827 2.4 Within-country dispersal rates 828 Within-country dispersal rates considers the number of alien taxa that have dispersed within the 829 country through the pathways of dispersal, including both taxa alien to the country, and those that 830 are native to the country, but which have been introduced to parts of the country where they are not 831 native [so-called native-alien populations, see (Nelufule et al. 2022)]. Data for within-country dispersal 832 have not been collated for taxa that are alien to the country, and so the indicator could not be 833 18 populated. However, based on the reviewed literature, alien and native taxa are dispersing within the 834 country through at least 31 different pathways (70%). 835 Of 132 native-alien populations that could be categorised with confidence, most were intentionally 836 transported to their new ranges (Nelufule et al. 2023)(Table S2.4), and were either intentionally 837 released (44 populations of 25 taxa) or escaped from captivity and cultivation (34 populations of 24 838 taxa). These intentionally introduced native-alien populations tended to be plants used for 839 ornamental purposes (21 populations of 16 taxa) and mammals introduced to game farms (20 840 populations of 11 taxa). There have also been accidental introductions of native taxa, including: 841 insects, gastropods, amphibians, and reptiles accidentally transported with products (29 populations 842 of 17 taxa), especially, plant products such as nursery materials; reptiles and marine crustacea 843 transported as stowaways on land vehicles and boats (7 populations of 3 taxa); and fish that have 844 spread through inter-basin water transfer schemes (8 populations of 4 taxa). Notably, as it is often 845 difficult to confidently ascribe an introduction pathway, and as the native ranges of species being 846 moved around are often not well circumscribed, it is expected that the number of native-alien 847 populations ascribed to the introduction pathways is likely to be significantly underestimated. This, as 848 well as their potential impacts (see below), means that the benefits of managing within-country 849 dispersal are likely to be much greater than suggested by current observed rates of within-country 850 dispersal. 851 In addition to the creation of potentially invasive native-alien populations, the within-country 852 movement of native taxa can have various potential concerning impacts, including harmful co-853 introductions and the losses in native genetic diversity. As discussed in section 2.3, wildlife ranches 854 are facilitating the movement of mammals around the country and, as a consequence, most of these 855 ranches have at least one native-alien population, but some have as many as 14 (Taylor et al. 2021a). 856 The most frequently found taxa with native-alien populations on these ranches were Aepyceros 857 melampus (impala) and Tragelaphus angasii (nyala) (Taylor et al. 2021). A recent genetic analysis 858 found that African Swine Fever Virus, a contagious and lethal disease of domestic pigs, is now found 859 in the south of the country, beyond the controlled area declared in 1935 (Craig et al. 2022). The 860 translocation of live Phacochoerus africanus (warthogs) to game farms and nature reserves outside of 861 their historical range has likely played a role in the dispersal of the virus (Craig et al. 2022). Similarly, 862 a phylogeographic analysis of Xenopus laevis (African clawed frog) and its monogenean parasite 863 Protopolystoma xenopodis indicated that human-mediated translocations of X. laevis had led to 864 different lineages of the species coming into contact (Schoeman et al. 2022). Bulk exports of X. laevis 865 from the south-western part of the country to urban centres in the north for research and teaching, 866 with subsequent escapes, have likely played a role (Schoeman et al. 2022). But, X. laevis is also used 867 19 as bait by recreational anglers, with anglers either collecting frogs or buying them from pet shops or 868 breeders for this purpose, and while some of these individuals escape, anglers also intentionally stock 869 water bodies for future use, and release surplus bait. Therefore, it is likely that through recreational 870 fishing individuals of different lineages are being moved to remote areas (Schoeman et al. 2022). 871 In terms of the within-country dispersal of taxa that are alien to the country, new research has shown 872 that people and vehicles are accidentally dispersing these organisms to the country’s protected areas, 873 and that while the intentional movement of taxa around by country is important, natural dispersal 874 mechanisms, like zoochory, are also playing a role at the national level. Materials taken from the shoes 875 of trail runners taking part in races in the Garden Route National Park were found to contain the seeds 876 of 33 plant species, of which 18 (55%) were alien to the country, and two were native to the country, 877 but alien to the Garden Route National Park (Smith and Kraaij 2020). Along Sani Pass in the Maloti-878 Drakensberg Park, exotic plant taxa have expanded their distributions from lower to upper elevations, 879 with the pattern of expansion indicating that human-aided long-distance dispersal is playing a role, 880 likely through the adhesion of plant propagules to the shoes of hikers, and vehicles moving up the 881 pass (Turner et al. 2021). Humans also continue to intentionally move alien taxa around the country 882 for various purposes, and the within-country dispersal of some taxa is being driven almost entirely by 883 these processes. Diopatra aciculata (the estuarine moonshine worm) is a cryptogenic species that has 884 expanded its range along the coastline, and arrived in the Knysna Estuary of the Garden Route National 885 Park approximately 15-20 years ago (van Rensburg et al. 2020). The species is used as bait, and 886 although collection often damages the worms, in some cases they can survive and regenerate. 887 Therefore, new populations may arise when fisherman transport and discard left over bait (Schoeman 888 and Simon 2023). In South Africa asexual reproduction is solely responsible for the natural dispersal 889 of the aquatic macrophyte Pontederia cordata (Pickerel weed) which is spread via rhizomes, and thus 890 most of its within-country dispersal is likely perpetuated by gardeners and horticulturists that trade in 891 the taxon, and dump plants and propagules; and fish farmers and golf course owners that may be 892 using the taxon as a stabilising plant for water bodies (Wansell et al. 2022). A Bayesian dynamic species 893 distribution model that was used to model the invasion of Plectranthus barbatus (Abyssinian coleus) 894 in the southern Cape showed the invasion of this species was also largely driven by human-mediated 895 long-distance dispersal that originated from the cities of first introduction (Botella et al. 2022). 896 Without human-mediated long-distance dispersal, the maximum population size of P. barbatus would 897 have been only 30% of the current population size (Botella et al. 2022). Natural processes are, 898 however, playing an important role in the dispersal of some alien taxa. Comparisons between alien 899 plant richness at dump sites and in the provinces in which the dump sites are found, have indicated 900 that alien plant propagules are being dispersed between localities in South Africa, with the dispersal 901 20 of some of these taxa likely being facilitated by omnivorous birds that fly long distances (Mokotjomela 902 et al. 2022). 903 Box 2.1. Work towards improving the pathways indicators 904 Meaningful indicators are required, at both national and international levels, to provide policy-905 relevant information on the status of biological invasions and their management (Wilson et al. 2018). 906 However, the implementation, over three reports, of the indicators used here to report on the status 907 of pathways has highlighted several issues. 908 Pathway frameworks are used to classify similar pathways into discrete categories. These frameworks 909 serve a variety of purposes, for example, they improve our knowledge on biological invasions, and 910 they can be used to predict future threats, inform management, and facilitate reporting to national 911 and international entities (Faulkner et al. 2020). A pathway framework proposed by the CBD as a global 912 standard (CBD 2014) has been set as a global biodiversity standard by the Darwin Core (dwc:pathway) 913 (Groom et al. 2019). This framework (see Figure 2.2) was developed to inform management, and assist 914 countries to achieve Aichi Biodiversity Target 9 of the CBD, specifically the requirement to identify and 915 manage introduction pathways (Essl et al. 2015, Scalera et al. 2016). Because of this, the framework 916 was incorporated into all of the pathways indicators used in this report, except for the high-level 917 indicator ‘Rate of unregulated introduction of new species’ (Wilson et al. 2018). However, 918 implementing the framework in the South African context has been a challenge (van Wilgen and 919 Wilson 2018, Zengeya and Wilson 2020), and a number of issues have been identified, particularly 920 with the sub-categories of the framework: (1) the differences between pathway sub-categories are 921 often unclear; (2) the available data are often not detailed enough for classification into the sub-922 categories (e.g., horticulture vs ornamental); (3) some pathways that are sub-categories have 923 contributed little to introductions (e.g., fur farming); (4) important pathways are not included in the 924 sub-categories (e.g., medicinal plant trade); and (5) some pathways that are likely to become 925 important in future cannot be classified using the framework (e.g., introductions with anthropogenic 926 debris, such as floating plastics) (Faulkner et al. 2020). Furthermore, while the framework was 927 developed to inform management, there is no evidence that it does, and there are no clear links 928 between the sub-categories and management actions (Faulkner et al. 2020). Work is currently 929 underway to develop and test a framework that will meet South Africa’s needs, by facilitating 930 reporting at both international and national levels, and inform management; this will be a feature of 931 the next report. 932 The high-level indicator ‘Rate of unregulated introduction of new species’ is based on the observed 933 rate of introductions (Wilson et al. 2018). However, this is well known to be a biased metric that can 934 21 lead to misleading patterns. A taxon recently recorded for the first time in the country, could have 935 been in the country for many decades (Box Figure 2.1), and this recording delay will impact the rate 936 of introduction if estimated based on raw introduction records. As such a constant rate of introduction 937 with a constant and imperfect detection rate will lead to an accelerating observed rate of introduction 938 (Solow and Costello 2004, Belmaker et al. 2009). Therefore, estimates of introduction rates must 939 consider the rate of discovery, which is often unknown. To address this, an indicator ‘Rate of Invasive 940 Alien Species Spread’ has been developed through the sTWIST project [cf. Box 1.2; and the preprint by 941 (McGeoch et al. 2021)]. Moreover, Target 6 of the Kunming Montreal Global Biodiversity Framework 942 (Box 1.1) has a proposed headline indicator ‘Number of Invasive Alien Species Introduction Events’. 943 The next report will pilot these approaches to obtain unbiased estimates of introduction rates in line 944 with the CBD's global biodiversity framework. 945 946 Box Figure 2.1 Examples of alien taxa in South Africa that were first recorded many years after they 947 are believed to have been introduced. A) Anisolabis maritima (the maritime earwig), was first recorded 948 in South Africa in 2015, but may have been in the country for more than a century (Griffiths 2018). B) 949 Rattus tanezumi (the Asian house rat) was not believed to be in South Africa, until 2005 when it was 950 identified during routine genetic monitoring (Bastos et al. 2005, 2011). The species is found in multiple 951 provinces, and its invasion may have gone unnoticed for quite some time, due to its morphological 952 similarity to the Rattus rattus (black rat) (Bastos et al. 2011). C) Euwallacea fornicates (the 953 polyphagous shot hole borer) was first recorded in Pietermaritzburg in 2017, but a DNA sequence for 954 the species was obtained from a specimen in Durban in 2012 as part of the Barcode of Life project 955 (Stouthamer et al. 2017). 956 22 2.5 Trends in pathway indicators 957 Indicator Trend1 Confidence Desired trend Current status and trend Outlook 1. Introduction pathway prominence → medium not applicable 13 introduction pathways play a major role socio-economically. There have been few qualitative changes to this during the period 2020–2022 despite temporary quantitative reductions due to COVID-19 response measures. For two pathways introduction pathway prominence was estimated for the first time. The trade and travel controls put in place to prevent the spread of COVID-19 caused a temporary decline in some introduction opportunities, but these introduction opportunities are returning to pre-pandemic levels and trends. There is a continuing need to track trends in travel and trade and for interventions to respond to such changes otherwise new harmful alien species will continue to be introduced. If, however, effective biosecurity measures are in place, the new biological invasions caused by increases in travel and trade will be reduced. 2. Introduction rates → Low not applicable (for regulated taxa) ↘ (for unregulated taxa) For regulated taxa: during 2020–2022, six new taxa were legally introduced for biological control, and one taxon that was already in the country was legally introduced for other purposes. For unregulated taxa: during 2020–2022, one new taxon was accidentally introduced as a contaminant of nursery materials, and two new taxa were introduced for ornamental or agricultural purposes, or to stabilise soil. However, several taxa introduced and recorded prior to 2020 were reported for the first time during 2020–2022. As such there is no strong evidence that actual introduction rates have changed over the past few decades. In many cases regulated taxa (for which the risks have been analysed and found to be acceptable) are expected to be a net benefit to the country, and in the case of biological control, assist with the control of biological invasions. Stringent processes are in place to minimise the risk that such introductions result in harmful invasions (section 5.1. in Chapter 5). Unless pathways are identified, prioritised and managed, potentially harmful alien taxa will continue to be accidentally and illegally introduced; and specifically, unless biosecurity improves, the rate of introduction of unregulated taxa will be a function of the volume of trade and travel. However estimated rates of introduction are sensitive to search effort and there is often a delay of several years between introductions happening and them being formally recorded (Box 2.1). New methods and approaches are needed to ensure that estimates of rates of unregulated introduction are responsive and can be used to evaluate the effectiveness of interventions. 1→ no change; ↗ an increase; ↘ a decrease 23 Indicator Trend1 Confidence Desired trend Current status and trend Outlook 3. Withincountry pathway prominence not assessed not applicable Information was only obtained for a few pathways. Many pathways are likely playing a role socio-economically within the country, but the extent of this role and how it has changed recently is not known. Restrictions on withincountry trade and travel to prevent the spread of COVID-19 had a short-term impact on the within-country dispersal opportunities provided by some pathways. Internal trade and transport are expected to increase over time. Trends in these pathways need to be tracked to ensure interventions are in place where they are needed. If this is not done harmful taxa will continue to spread, native taxa will be introduced and possibly cause impacts in parts of the country where they are not native, and valuable assets will be put at risk. 4. Withincountry dispersal rates not assessed not applicable (for regulated taxa) ↘ (for unregulated taxa) Alien and native taxa are dispersing within the country through at least 31 different pathways. National-scale data have yet to be collated for alien taxa, but information has become available for native-alien populations. Most recorded native-alien populations are plants introduced for horticulture, or mammals for aesthetics. But native-alien populations are also the result of accidental introductions, for example, organisms moved with transported plants or plant products, or that disperse through inter-basin water transfer schemes. Alien organisms are being introduced, often accidentally, to protected areas, and while human-aided dispersal is driving the dispersal of some taxa, natural processes are also playing an important role at a national scale. Unless pathways that facilitate the within-country dispersal of taxa are identified, prioritised, and managed, the spread of these taxa will increase, and so there will be increases in both the rate of expansion of currently invasive taxa, and in the likelihood that alien taxa will find a suitable part of the country in which to become invasive. Native-alien populations likely differ in their impacts to other alien populations, and to inform management, there is a need to improve our understanding of the extent of this problem, and how these populations are being introduced; noting that regulation might be needed below the national level. High level indicator A. Rate of unregulated introduction of new species → low ↘ Over the last decade (2013–2022) approximately three new taxa were introduced per year either accidentally or intentionally but illegally. This is similar to previous estimates. Opportunities for the introduction of alien taxa are expected to increase as the volume of trade and travel increases. Whether this results in the introduction of more invasive taxa will depend on the degree to which key pathways are identified, prioritised, and managed. Improvements to inspection, management, and incursion response at-border would strengthen South Africa’s biosecurity. See chapter 5 for details on some positive developments on this front. 958 24 Chapter 3: Species 959 Lead authors: Tsungai A. Zengeya, Katelyn T. Faulkner, Laura Fernández Winzer, Sabrina Kumschick, 960 Siyasanga Miza, Emily J. McCulloch-Jones, John R. Wilson 961 Contributing authors: Aviwe Sifuba, Whitney Engelbrecht 962 Key findings for species 963 • South Africa is a hotspot of plant invasions with several freshwater fishes also causing 964 significant negative impacts on biodiversity. Preliminary findings indicate 13 plants, five 965 freshwater fishes, one invertebrate have had Major or Massive impacts (as per the IUCN’s 966 EICAT scheme). However, as only few taxa (38) have been formally assessed, and so this 967 number is expected to increase. 968 • The process of documenting and tracking changes in the status of alien species has been 969 substantially improved through the development of workflows to ensure work is properly 970 documented and repeatable. This will facilitate tracking of alien species over time and can 971 feed into management planning and facilitate regulatory decisions. 972 • The number of distribution records from citizen science platforms has substantially increased 973 the knowledge of the distribution of some alien taxa, but a decline in recent active surveillance 974 at least for plants (i.e., hiatus in the southern African Plant Invaders Atlas) represents a 975 significant reduction in the ability to systematically evaluate trends in invasions over time. 976 • The majority of alien species are localised and only a few were widespread. However, the 977 potential for spread is large and the extent of most species will continue to increase unless 978 effective control is put in place. 979 • The phenomenon of native-alien populations (i.e., taxa which are native to a part of South 980 Africa but have been introduced to and naturalised in parts of South Africa to which they are 981 not native) has been circumscribed and quantified for the first time, 77 native taxa have 982 formed 132 native-alien populations. Preventing such invasions will require a greater focus on 983 managing species movements within the country. 984 Key gaps for species and sites1 985 • Data on the distribution and abundance of alien species need to be collected, collated, and 986 integrated into national and global databases to facilitate the planning of interventions. 987 1The gaps listed are the same as in the second report as the situa�on has not changed 25 • The systematic quantification of the impacts of biological invasions would: facilitate the 988 prioritisation of interventions targeting particular species and particular sites; provide the 989 justification for government investment to control biological invasions; and provide important 990 background to communicate the issue to society. 991 Indicators covered in the species chapter 992 993 3.1 Number and status of alien species 994 A total of 5121 taxa were assessed for presence in South Africa of which 3189 taxa are present, the 995 presence of 1197 taxa is doubtful, and 735 are absent1 (Table 3.1, S3.1). Over half of the alien taxa 996 recorded as present were plants, in line with the view that South Africa is a hotspot for plant invasions 997 and relatively (compared to other regions) less affected by animal invasions (van Wilgen et al 2020). 998 Table 3.1 The number of alien species present or possibly present in South Africa for which 999 information has been formally collated as at December 2022. For more details, including taxa assessed 1000 and scored as absent, see Table S3.2 and Appendix 2. 1001 Taxa Doubtful Present Bacteria 0 3 Chromista 1 15 Fungi 8 104 Invertebrates 231 952 Plantae 843 1633 Vertebrates 114 482 1002 For each taxon recorded as present the evidence is clearly specified in Appendix 2 and the names have 1003 been checked against various taxonomic sources. However, the list is not comprehensive. The 1004 presence of many alien taxa needs to be confirmed and documented; many data sources still need to 1005 be incorporated into the list; and it is likely that many alien taxa have not, as yet, been recorded (see 1006 supplementary material S3.2 for further details on progress made to update the list). In particular, 1007 1The vast majority of taxa alien to South Africa have never been introduced. For example, assuming there are ~350,000 vascular plants alien to South Africa, the status of <1% of these has been formally assessed in this report. Most taxa assessed and found to be absent were assessed as they were listed as prohibited under the A&IS Regulations of 2014 or 2016 (see Section 1.2). 5. Number and status of alien species 6. Extent of alien species 7. Abundance of alien species SPECIES 8. Impact of alien species HIGH LEVEL B. Number of invasive species that have major impacts 26 many alien taxa in captivity or cultivation are not included; particular taxonomic groups that have not, 1008 yet, been systematically incorporated into the lists (e.g., well over half of 200 of the most common 1009 mushrooms seen in South Africa are likely to be alien; cf. Goldman & Gryzenhout, 2019); and, as noted 1010 in previous reports, focussed research effort will often identify many new alien taxa (e.g., Magona et 1011 al. 2018). Given this is a revised process, and that substantive and systematic gaps remain in terms of 1012 collating available information, it is not meaningful to compare values with the previous report or to 1013 an updated baseline. 1014 3.2 Extent of alien species 1015 Occurrence data were updated based on data published by the Global Biodiversity Information Facility 1016 (GBIF) and were only available for a few taxa. As in previous reports a few taxa are widespread 1017 invaders, but many alien taxa are only known from a few sites (Figure. 3.1). The integration between 1018 the widely used citizen science platform iNaturalist and GBIF means that the flow of information from 1019 observations to incorporation into this report has improved significantly. However, the southern 1020 African Plant Invaders Atlas (SAPIA) was put on a hiatus in the first quarter of 2020. SAPIA provided 1021 standardised data on the distribution of alien plants through collating submissions from experts 1022 (which can now occur via iNaturalist, though with different quality control procedures) and through 1023 dedicated road-side surveys across the country (which is no longer happening). The active surveillance 1024 effort of SAPIA allowed for trends in the extent of plant invasions to be reliably evaluated over time 1025 (cf. Henderson and Wilson, 2017); the loss of this monitoring represents a significant decline in the 1026 ability of South Africa to track plant invasions. The use of remote sensing techniques continues to 1027 promise much to address some of these issues, but remote sensing has its own limitations, and 1028 systematic, repeatable information of the type require to track invasions over time are not yet 1029 available. 1030 33 Chapter 4: Sites1 1111 Lead authors: Tsungai Zengeya; Emily J. McCulloch-Jones; Brian W. van Wilgen 1112 Contributing authors: tbc 1113 Key findings for sites 1114 To be added (cf. key findings on Chapter 3: Species) 1115 Key gaps for species and sites2 1116 • Data on the distribution and abundance of alien species need to be collected, collated, and 1117 integrated into national and global databases to facilitate the planning of interventions. 1118 • The systematic quantification of the impacts of biological invasions would: facilitate the 1119 prioritisation of interventions targeting particular species and particular sites; provide the 1120 justification for government investment to control biological invasions; and provide important 1121 background to communicate the issue to society. 1122 Indicators covered in the sites chapter 1123 1124 4.1 Alien species richness 1125 Comprehensive estimates for alien species richness are limited to small areas and for particular taxa 1126 (e.g., McLean et al. 2018, Baard and Kraaij 2019; Cheney et al. 2019). Therefore, broad-scale species 1127 richness estimates can only be reliably estimated for invasive species. Invasive species are distributed 1128 across the country, with most broad-scale administrative units and biogeographical regions being 1129 invaded by a variety of taxa (Table 4.1). 1130 At a provincial scale, there has been minimal change in alien species richness. Most alien species are 1131 found in the Western Cape, Eastern Cape, and KwaZulu-Natal (Figure 4.1A). The most prominent 1132 increase in the number of alien species per province was in the Western Cape (128 species) and there 1133 were moderate (29–84 species) to low (1–28 species) increases in alien species richness in the other 1134 1Not all available information to update the indicator values for all the species listed in Appendix 2 has been captured yet, and the material presented in this draft is based on an analysis of incomplete information. In the final report, updates will be drawn for all taxa where data are available. 2The gaps listed are the same as in the second report as the situation has not changed. SITES 9. Alien species richness 10. Relative invasive abundance 11. Impact of invasions HIGH LEVEL C. Extent of area that suffers major impacts from invasions 34 provinces (Figure 4.1B). Given the nature of the data sources it is likely that these patterns are largely 1135 a result of changes in records on iNaturalist feeding through to GBIF. 1136 At a finer scale, only 7% (120 out of 1673 quarter-degree grid cells) had 50 or more alien species. The 1137 recorded alien species richness appears to be highest around major urban centres (Figure 4.1C). As 1138 previously noted, this is likely because some species are commensal with humans, most were first 1139 introduced to urban centres, and because of greater sampling around urban areas. This is partly 1140 reflected in the notable increases in alien species richness around urban areas primarily from 1141 increased observation from the citizen scientist platforms such iNaturalist (Figure 4.1D). 1142 Information on alien species richness was available for SANParks and Cape Nature protected areas 1143 (Table 4.1E). 1 014 invasive species (excluding biocontrol agents and marine species) are reported to 1144 occur across the SANParks estate. Of these, there are 256 animal species and 758 plant species. 333 1145 of these taxa are listed under the A&IS Regulations, the remaining 681 species are unlisted. No 1146 protected area complex is alien-free. Three protected areas (Garden Route NP, Kruger NP, and Table 1147 Mountain NP) had more than 100 invasive species. In 2022, Cape Nature listed 759 invasive species 1148 across their estate of 31 protected area clusters. The number of invasive species included 502 plants 1149 and 257 animals of which 404 are listed under the A&IS Regulations. No protected area complex is 1150 free of invasive species, but the distribution of invasives between protected areas is highly skewed 1151 with only four protected areas reporting more than 40 invasive species. 1152 Table 4.1. Invasive species richness in South Africa for different broad-scale administrative units and 1153 biogeographical regions1. The estimates of change are made with low confidence because most 1154 reported increases arise from the formal recording of species that have probably been present for 1155 some time. Data are of South African records available from GBIF (https://www.gbif.org/) and the 1156 southern African Plant Invaders Atlas (SAPIA) for continental South Africa, from Robinson et al. (2020) 1157 for marine eco-regions. NA = not assessed. Further details will be provided in supplementary material, 1158 see Appendix 1 for the data sources, and Appendix 2 for the full species list. Information on the Prince 1159 Edward Islands is presented in Chapter 6 and the accompanying appendices and supplementary 1160 material. 1161 A) Invasive terrestrial species and invasive freshwater plant species richness per province. 1162 Province / Region End of 2019 End of 2022 Change Eastern Cape 148 Free State 88 Gauteng 133 KwaZulu-Natal 184 Limpopo 106 Mpumalanga 210 Northern Cape 64 North West 81 1 Tables still to be updated 35 Province / Region End of 2019 End of 2022 Change Western Cape 186 B) Invasive terrestrial species and invasive freshwater plant species richness per biome. 1163 Biome End of 2019 End of 2022 Change Albany Thicket 108 Desert 9 Fynbos 251 Forest 10 Grassland 230 Indian Ocean Coastal Belt 156 Nama-Karoo 76 Savanna 241 Succulent Karoo 55 C) Invasive freshwater animal species richness per water management area. 1164 Water management area End of 2019 End of 2022 Change A-Limpopo 4 B-Olifants North 2 C-Vaal 2 D-Orange 3 E-Olifants West 2 F-Buffels 0 G-Berg 3 H-Breede 1 J-Gouritz 1 K-Krom 2 L-Gamtoos 2 M-Swartkops 2 N-Sundays 1 P-Bushmans 0 Q-Great Fish 2 R-Keiskamma 2 S-Kei 4 T-Mzimvubu 2 U-Mkomazi 2 V-Tugela 4 W-Mfolozi 3 X-Komati 4 D) Marine invasive species richness per marine ecoregion. 1165 Marine ecoregion End of 2019 End of 2022 Change Agulhas 41 Natal 25 Delagoa 8 Southern Benguela 39 Southeast Atlantic (offshore) 0 Southwest Indian (offshore) 0 E) Invasive species in protected areas in South Africa. 1166 36 Invasive species richness Cape Nature SANParks End of 2019 August 2021 Change End of 2019 End of 2022 Change 0 0 0 0 1–10 3 0 0 10–20 10 6 6 21–30 4 3 3 31–40 10 4 4 41–50 3 1 1 >50 1 6 6 1167 4.2 Relative invasive abundance 1168 There are no country-wide estimates for the relative abundance of invasive species, but there are 1169 estimates for invasive plants in protected areas managed by the South African National Parks, 1170 Ezemvelo KwaZulu-Natal Wildlife and Cape Nature. Estimates of relative invasive abundance in these 1171 protected areas from 2019 indicated that invasions were minor to moderate (Table 4.2). The estimates 1172 for protected areas managed by Cape Nature have not changed between 2019 and 2022. 1173 Table 4.2. Estimates of relative invasive abundance in South Africa`s protected areas based on 1174 percentage plant cover. Alien-free means that no alien species are recorded in the protected area1. 1175 Relative invasive abundance Number of Cape Nature`s protected areas Number of Ezemvelo KwaZulu-Natal Wildlife`s protected areas Number of SANParks protected areas 2018 2021 2019 2022 2019 2022 Alien-free 0 0 1 0 Minor <2% 12 11 59 14 Moderate 2-10% 5 7 39 2 Extensive 10-50% 12 11 22 0 Dominant >50% 0 0 0 0 1176 1this will be updated in the final report 37 1177 1178 Figure 4.1. Alien species richness in South Africa per A) province and C) quarter-degree grid cell as of December 2022 based on occurrence records from 1179 GBIF and SAPIA, and B), D) the change in these values since December 2019. Data from GBIF. In the final report, these patterns are to be placed in the 1180 including in the context of Strategic Water Sources Areas (SWSAs).1181 38 4.3 Impact of invasions1 1182 Evaluations on impact are often piecemeal or fraught with major assumptions. In 2008, van Wilgen et 1183 al. (2008) performed a biome-scale assessment of the impact of invasive plants on ecosystem services 1184 in South Africa. This study has been pivotal in our understanding of the impacts of invasive plants 1185 (invasive trees in particular) in South Africa but has since not been revised or reassessed. We intend 1186 to replicate the van Wilgen et al. (2008) study and develop workflows (sensu Seebens et al. 2022) to 1187 improve the applicability and repeatability of the methods. The process is intended to help identify 1188 gaps in the study, and aspects of the methods that could benefit from updated data sources and recent 1189 modelling techniques. Ultimately, the workflow would provide a synthesised, reproducible, and 1190 transparent method that can be used to assess the impacts of invasive plant species over time. It 1191 should be noted that particular focus will be given to the impacts of invasive trees on water resources 1192 in South Africa. The metric used to communicate this impact over time has varied greatly and we 1193 further intend to identify a standard metric that can be used to express impact to allow for continued 1194 comparisons. 1195 Box 4.1 Estimating the costs of invasions to South Africa 1196 Invasive species affect ecosystem functioning and hinder the delivery of ecosystem services, often 1197 leading to significant economic losses (Vaissière et al. 2022). Historically, the economic impacts of 1198 biological invasions (in terms of damage and management costs), have been poorly represented in the 1199 literature and estimates are generally unreliable as they are fraught with major assumptions (Cuthbert 1200 et al. 2020). In an attempt to standardise estimate of economic impacts of invasions at national and 1201 global scales, Diagne et al. (2020b) developed InvaCost. InvaCost is a global-scale data repository of 1202 information on economic costs associated with biological invasions from peer-reviewed or grey 1203 literature. InvaCost studies have to date been completed for a range of focal topics, including, 1204 synthesis at global and national scales and for various taxonomic groupings (Zenni et al. 2021; and for 1205 an updated list of InvaCost studies see https://invacost.fr/en/outcomes/). 1206 As part of this report, an InvaCost-type analysis was conducted for South Africa. Data were obtained 1207 from 67 source documents that were published in the period 1960–2023. The observed cost of 1208 damage was ZAR49.2 billion (adjusted to 2021 values) with predicted damages at ZAR178.8 billion. In 1209 contrast, the money spent on control was only ZAR8.6 billion, with predicted management costs at 1210 1ongoing work includes the development of systematic processes for evaluating impact studies and work-flows including ways of scaling up; link to other biodiversity assessments such as the National Biodiversity Assessment (NBA) and previous studies that looked at the impacts on biodiversity, water, and grazing (e.g. van Wilgen et al. 2008) 39 ZAR 377.7 billion. Thus, estimates of damage cost are significantly greater than estimates for 1211 management; and the predictions of money spent needed to reach management thresholds were 1212 consistently an order of magnitude higher than actual money spent. 1213 1214 Box Figure 4.1 Estimates of the relative cost of invasions and money spent on management for 1215 various taxa (unpublished data, updated to May 2023). 1216 Plants accounted for the majority of costs, however a few taxa and a few studies accounted for almost 1217 all of these estimates. For example, 63 % of all observed damage costs are attributable to Acacia 1218 mearnsii; and 73% of predicted management costs and 99% of costs due to animals were attributed 1219 to a handful of studies on the recent invasions by Euwallacea fornicatus (the polyphagous shot hole 1220 borer) and its fungal symbiont. Similarly, there are substantive skews in the availability of information 1221 on the money spent controlling biological invasions. Various stakeholders are known to spend money 1222 controlling biological invasions (see Table 5.1), but only for the Working for Water programme was an 1223 almost complete data on expenditure available. Nonetheless, the data collated as part of this exercise 1224 represents a major improvement in the transparency and accessibility of data related to the money 1225 spent on and estimated damage caused by biological invasions. 1226 1227 Management Observed Damage Diverse Animal Birds Crabs Fishes Insects Snails/ Slugs Diverse Plants Aquatic Plants Cacti/ Succulents Invasive Trees Shrubs/ Herbs Vines/ Creepers Grasses/ Reeds Mixed Taxa 40 4.4 Trends in sites indicators 1228 Indicator Trend1 Confidence Desired trend Current status Outlook 9. Alien species richness ↗ low ↘ (for invasive species) Increase in extent were seen in various provinces (particular the Western Cape), although without active surveillance this might be an artefact of more records being submitted to the citizen science platform iNaturalist. The development of a robust and reliable monitoring methodology should be seen as a priority, because in the absence of reliable information on species richness and relative abundance, neither the magnitude of impacts nor the effectiveness of management can be properly assessed. 10. Relative invasive abundance → low ↘ Estimates were only available to date for one groups of protected areas. There have been no major changes in the relative abundance of invasive plants in Cape Nature protected areas. Achieving consistency in tracking relative abundance in protected areas could be facilitated by the inclusion of a standardised monitoring protocol in the criteria for the preparation of management plans which were developed by the DFFE in terms of the A&IS Regulations. It is expected that existing invasions will densify unless managed. The costs of control and the impacts caused often increase dramatically with the level of invasion. 11. Impacts of invasions not reassessed yet ↘ not reassessed yet Impacts are likely to increase as invasive species continue to spread, and as control efforts are scaled back in response to fiscal constraints. This underscores the importance of re-focussing control efforts on agreed priority sites, and taking steps to improve control effectiveness. Impacts of invasions on sites have been quantified using different approaches and metrics over time and it is not yet possible to compare values with previous report. High level indicator C. Extent of areas that suffer major impacts from invasions not reassessed yet ↘ not reassessed yet If control efforts focus on priority sites (e.g., sites that provide water to Cape Town’s dams) then there will be significant returns on investment. However, without agreement on priorities, there is a substantial risk that control could remain ineffective, and the area that suffers from major impacts will continue to grow. Estimates of the full magnitude of impacts require more accurate assessments of the extent of invasions. This, in turn, requires effective mapping of the areas invaded and monitoring of spread. Such monitoring is currently lacking, and without which effective prioritisation is not possible. 1229 1→ no change; ↗ an increase; ↘ a decrease 41 Chapter 5: Interventions 1230 Lead authors: Brian W. van Wilgen, Katelyn T. Faulkner, John R. Wilson & Márthan Theart 1231 Contributing authors: Nicholas Cole, Julie A. Coetzee, Whitney Engelbrecht, Phetole Manyama, Emily 1232 McCulloch-Jones, Themba Mnguni, Zachariah Mokganye, Iain Paterson, Leoni Pretorius, Roger Price, 1233 Louise Stafford, Andrew A. Turner, Karabo Wanjau, Andrew Wannenburgh & Costas Zachariades. 1234 Key findings regarding interventions 1235 • The NEM:BA A&IS Regulations and Lists were revised and promulgated in 2020. These 1236 amendments are considered to have improved the regulatory regime. 1237 • However, the rationale for changes to the lists (the prohibited list was removed and the 1238 listings for 73 taxa changed) was not documented. A process has been set up to ensure that 1239 changes to the lists can be made more regularly, transparently, and informed by evidence. 1240 • A substantial area of commercial forestry has been exempted from requiring permits to 1241 cultivate and trade in listed invasive trees. As a result, commercial forestry remains as an 1242 unregulated seed source for re-invading adjacent areas that have been cleared. 1243 • At least ZAR 1.4 billion has been spent on the management of biological invasions over the 1244 period 2020–2022. However, the money spent has declined steadily in real terms since 2015. 1245 • The recent entry of several NGOs who have provided funding for the control of alien trees in 1246 catchment areas, and of invasive freshwater fish, is an encouraging development. 1247 • A lack of adequate planning remains a constraint to effective management, and a lack of 1248 monitoring means it is difficult to evaluate the effectiveness of management that is in place. 1249 • Plans are assumed to exist for the management of 40 of 44 identified introduction pathways, 1250 although no plans have been formally approved. The management of seven pathways is 1251 effective and of one pathway is partially effective. For the remainder, the effectiveness of 1252 management is either unknown (14 pathways), ineffective (17 pathways), or there is no 1253 management (five pathways). 1254 • 23 species (of which 16 are regulated and 7 are unregulated) have management plans in place. 1255 These are all actual or potential targets for national eradication. 1256 • About one third of the 566 regulated taxa have received some form of active treatment (e.g. 1257 clearing) over the past three years. However, the effectiveness of control is unknown for most 1258 of the treated species. A few species were assessed as being under permanent control (based 1259 on an assessment of complete biological control). 39 alien pests of agricultural crops were 1260 42 subjected to biological control, but only one of these pests is listed under the NEM:BA A&IS 1261 Regulations. The numbers will be updated in the final report. 1262 • The area covered by current site management plans has decreased from 14.7% to 8.2% of the 1263 estimated invaded area, due to some plans having lapsed. However, there has been an 1264 improvement in the adequacy of planning, with plans covering 45.1% of the planned area 1265 being assessed as adequate (compared to 2% previously), and 53.6% as partially adequate 1266 (compared to 42% previously). 1267 • Control operations reached 1% of the estimated invaded area between 2020 and 2022. There 1268 is evidence that control efforts have reduced the area invaded at some sites, but most invasive 1269 species have continued to expand their range when assessed at a national scale. 1270 • The Working for Water programme provides more than 80% of the money known to be spent 1271 on the management of biological invasions in South Africa. The exact proportion cannot be 1272 assessed as most of the funding reported by other agencies is sourced from the Working for 1273 Water programme, but the proportion is typically not reported. 1274 • The paucity of monitoring of the outcomes of control measures, along with the absence of 1275 management plans with clear goals, remains a substantial impediment to assessing the 1276 effectiveness of control measures. 1277 Key gaps regarding interventions1 1278 • A comprehensive policy, and a strategy to implement such a policy, is needed to guide 1279 interventions on biological invasions in South Africa. 1280 • The absence of formal programmes to monitor the effectiveness of interventions in terms of 1281 outputs and outcomes means that the efficacy of control cannot be demonstrated, control 1282 measures cannot be compared and improved, and it is not clear whether progress is being 1283 made to reduce the negative impacts of invasions. 1284 1285 1286 1These key gaps have not changed since the second report. 49 Table 5.1 Money reported as having been spent on the management of biological invasions in South Africa by different organisations between 2020 and 1447 2022. The amounts are totalled for three years, unadjusted for inflation. Inputs from various organisations and many stakeholders, particularly in the 1448 private sector, have not been included (and so the overall figure should be viewed as a lower estimate). However, it is also possible that there may be some 1449 double counting, as some of the money spent by implementing agencies may also have been reported by the Department of Forestry, Fisheries and the 1450 Environment (DFFE)’s Working for Water Programme, this is to be addressed in the final report. 1451 Organisation Money spent on Money spent (ZAR) Notes Agricultural Research Council Biological control research 104 495 930 ZAR 69 700 073 from the DFFE and ZAR 34 795 857 from the ARC. Buffalo City (East London) Protected areas within the municipal boundaries 9 151 000 This includes other activities such as clearing of vegetation along road verges Cape Nature 31 protected areas in the Western Cape Province 9 299 189 Most of this money came from the Working for Water programme and so there may be some double counting Centre for Biological Control, Rhodes University Biological control research and implementation 82 000 000 ZAR 59 million from Working for Water; ZAR 15 million from the DST-NRF via the South African Research Chairs Initiative; ZAR 8 million from other sources. The bulk is spent at Rhodes University, but part of the funding is distributed to the Universities of Cape Town, Witwatersrand, KwaZulu/Natal, Mpumalanga, and Fort Hare City of Ekurhuleni (Gauteng) Management of aquatic ecosystems 17 700 000 Funding has been expended mostly on Pontederia crassipes (water hyacinth), Arundo donax (giant reed), and Nymphaea mexicana (yellow water lily) invading aquatic ecosystems Department of Agriculture, Land Reform and Rural Development Responsible for Conservation of Agricultural Resources Act (CARA) and other legislation. Maintains a presence at all border posts. No estimate available The expenditure on these activities was requested from DALRRD but no input was received. DFFE animal control projects Control of invasive animals No estimate available The expenditure on these activities was requested from DFFE but no input was received. DFFE Biosecurity Monitoring activities aimed at interception of alien species at OR Tambo International Airport 13 820 241 The figure reported here does not cover the costs of all of the biosecurity activities undertaken by the DFFE, nor does it include departmental overheads. 50 Organisation Money spent on Money spent (ZAR) Notes DFFE high altitude teams Specially trained teams deployed to control invasive plants in relatively inaccessible or mountainous terrain 255 298 699 Budgeted amount for financial years. The DFFE reported an amount of ZAR 208 237 112, and 22.6% was added to account for overheads (van Wilgen et al., 2022) DFFE Natural Resource Management programmes (Working for Water) Approximately 250 projects established to control established invasive plants across all 9 provinces 470 972 650 This covers the period 1 January 2020 to 30 April 2022. The DFFE was not able to supply data for the period 1 May to 31 December 2022. The DFFE reported an amount of ZAR 384 153 875, and 22.6% was added to account for overheads (van Wilgen et al. 2022). Funding (including overheads) can be broken down into: ZAR 413 206 893 for widespread alien plants (See Table 5.2 for a breakdown by the most costly species); ZAR 47 812 384 for eradication targets; ZAR 37 336 449 for native bush encroachers; and ZAR 10 475 934 for alien aquatic weeds. DFFE value added industries Establishment and operation of factories intended to produce a range of products with biomass sourced from alien plant control operations 237 223 158 Budgeted amount for financial years. The DFFE reported an amount of ZAR 193 493 604, and 22.6% was added to account for overheads (van Wilgen et al. 2022). Gauteng provincial reserves (North) Three protected areas in the north of Gauteng province 6 000 Only includes costs of herbicide and a pair of scissors, staff time not included. Gauteng provincial reserves (South) Three protected areas in the south of Gauteng province 2 300 000 Invasive Fish Species Management (IFSM) Control of Cypinus carpio (common carp) in Groenvlei lake, Western Cape. 450 000 IFSM is a NGO in the Garden Route. Amount spent between 2018 and 2022 was ZAR 750 000 (estimate supplied by the director, Johnny Snyman). Assuming an equal amount spent each year, the estimate for 2020 to 2022 is ZAR 450 000. South African National Biodiversity Institute Preparation of status reports, risk analyses, incursion response, taxonomy, research, and human capacity development (placement of interns) 145 454 000 Money obtained on contract from DFFE South African National Parks 22 national parks across South Africa, and outside of parks in buffer zones 3 985 260 SANParks reported an amount of ZAR 199 263 000, but only 2% of this came from the SANParks budget, the rest from DFFE Natural Resource Management programmes (Working for Water). 51 Organisation Money spent on Money spent (ZAR) Notes The Greater Cape Town Water Fund Catchments of the Berg and Theewaterskloof dams, and Atlantis aquifer, Western Cape Province ~100 000 000 Estimated amount provided by the project manager Volunteer groups 52 volunteer groups from the Western Cape who clear invasive plants 5 106 241 Data from Jubase et al. (2021). This is the current cost to clear the equivalent area that has been cleared by volunteer groups, some of which have been operational since 1980. A portion of this amount may therefore have been spent prior to the period covered by this report, but is reported here in full as it has not been reported before. Worldwide Fund for Nature South Africa (WWF-SA) 11 strategic water source areas in the Western Cape fynbos catchments, and in the Eastern Cape and KwaZulu-Natal Drakensberg. 26 603 201 Some of this money may be included in the Greater Cape Town Water Fund estimate. 1452 52 Table 5.2 Money spent clearing selected invasive plants in South Africa by the Working for Water 1453 programme. This is for the period 2020 to the end of April 2022. Values include a 22.6% overhead. 1454 Spending on these taxa represent about two thirds of all the money disbursed. 1455 Taxon Money spent (ZAR) % of total cost Acacia mearnsii 88 634 536 18.8 Lantana camara 55 549 985 11.8 Acacia saligna 32 342 218 6.9 Neltuma species and hybrids 28 605 969 6.1 Acacia melanoxylon 22 182 801 4.7 Acacia dealbata 21 189 774 4.5 Rubus cuneifolius 13 391 654 2.8 Pinus pinaster 13 204 338 2.8 Chromolaena odorata 12 114 313 2.6 Acacia cyclops 9 079 521 1.9 Psidium guajava (and possibly other Psidium spp.) 8 307 475 1.8 Eucalyptus camaldulensis (and possibly other Eucalyptus spp.) 8 144 657 1.7 1456 5.3 Input—planning coverage 1457 Pathway management plans: As reported in the previous report, no formally approved management 1458 plans for pathways have been developed by DFFE, and pathway management plans are not required 1459 as per the NEM:BA A&IS regulations. However, management is in place for 39 of 44 pathways. 1460 Therefore, it is assumed that plans are in place for those pathways, though no records of the plans 1461 being formally approved were available. In addition, ballast water management plans have been 1462 developed, but not implemented, thus 40 pathways are assumed to have plans in place (see 1463 supplementary material S5.8). 1464 Species management plans: The NEM:BA requires [Section 75(4)] the Minister to ensure the 1465 coordination and implementation of plans (called programmes in the Act) for the prevention, control 1466 and eradication of invasive species. No plans have been formally adopted, although, as reported 1467 previously, plans have been prepared for two species (Parthenium hysteropherus and Campuloclinium 1468 macrocephalum), two genera [Acacia and Neltuma (previously Propsopis)] and one family (Cactaceae) 1469 of invasive plants. In addition, 23 plans have been developed for species targeted for, or considered 1470 for, nation-wide eradication. Of the 23 species management plans, 13 were scored as adequate, 8 as 1471 partially adequate and 2 as inadequate. Most (16) of these species are category 1a, the rest (7) are not 1472 currently listed (see supplementary material S5.10 for how the plans were scored and Table S5.7 for 1473 the list of taxa). 1474 Site management plans: In terms of the NEM:BA A&IS Regulations, the responsibility for drawing up 1475 site management plans for sites lies with individual landowners (state or private), because they are 1476 responsible by law for the control of listed invasive species on their land. A database has been 1477 53 developed to track planning coverage for sites (see Table 5.4, and supplementary material S5.11). All 1478 plans submitted to SANBI for the first three status reports were captured into this database. 1479 In total, over the three reporting periods to date, 91 plans covering 4.5 million ha have been submitted. 1480 Assuming that there is no overlap, this amounts to 23% of the estimated area covered by invasions in 1481 South Africa (19.5 million ha, see van Wilgen et al. 2022). Of these, 59 plans covering 1.6 million ha are 1482 considered to be current (i.e. covering 8.2% of the estimated invaded area), and 32 have lapsed, and 1483 are assumed not to have been updated. 1484 Cape Nature, the provincial authority in the Western Cape Province, provided the largest coverage by 1485 submitting 19 plans covering 607 142 ha for protected areas under their control (Figure 5.1). Plans 1486 submitted by eight municipalities (3% of the 257 municipalities in the country) accounted for the next 1487 largest area (567 329 ha) planned. The only other conservation agencies that submitted plans were 1488 South African National Parks and provincial protected areas in Gauteng Province. Plans were submitted 1489 for 3 out of 19 national parks in the country (Agulhas, West Coast and Bontebok, all in the Western 1490 Cape). Site management plans for the remaining national parks are being compiled, but were not 1491 available for assessment. The plans for six protected areas in Gauteng Province covered 25 000 ha and 1492 are included in Figure 5.1 under “other government agencies”. Plans in this category covered 371 442 1493 ha. There was a small contribution (in terms of area covered) from the private sector. 1494 In the first status report (SANBI and CIB 2018) planning coverage was estimated to be 2.4 million ha 1495 on the basis of plans submitted. Not all of these plans were obtained in the subsequent report, and so 1496 it is unclear whether the plans have been updated or have lapsed. The area covered by current plans 1497 therefore appears to have decreased, although this conclusion can only be based on plans that were 1498 submitted; other plans probably exist but were not available for assessment. However, there appears 1499 to have been a marked improvement in the adequacy of planning. In the first report, plans for 98% of 1500 the area covered were assessed as inadequate. The current estimate is that planning in almost half 1501 (45.1%) of the area was adequate, and just over half (53.6%) was partially adequate, with only 1.3% of 1502 the planning being scored as inadequate. The adequacy of planning coverage, where it is done, thus 1503 appears to have improved substantially since the last status report. 1504 1505 54 1506 Figure 5.1 The area covered by current site management plans submitted to SANBI by different groups 1507 within government and the private sector. Data summarized here are for plans that are still current in 1508 terms of the stated planning horizon (plans that did not include a planning horizon were assumed to 1509 be valid from the date of submission for 5 years). Plans that were submitted for previous status reports, 1510 and that are still current, or have been updated, are included. Shading indicates the adequacy of the 1511 plan. 1512 55 Table 5.4 Site management plans submitted by organisations for assessment in terms of their adequacy. In cases where no plans were submitted to SANBI the 1513 area covered by the plans is considered to be 0. 1514 Organisation Sites to be managed Area covered by plans (ha) Adequacy of plans Notes Department of Forestry, Fisheries and the Environment Natural Resource Management programmes (Working for Water) Working for Water has many projects across all 9 provinces 0 NA No plans were submitted. Working for Water does not prepare management plans as this is the responsibility of individual landowners (private and state) to who they provide support. However, Working for Water has funded the development of six demonstration “management unit control plans” (MUCPs)1 for the upper catchment of the Berg River; Cape Nature’s Waterval Centre; the catchments of the Holsloot, Keurbooms and Karatara rivers; and the Greater Simonsberg Conservancy. They will be assessed once they are received. Cape Nature Protected areas in the Western Cape Province. 607 142 Adequate (486 476 ha) Partially adequate (120 666 ha) 19 plans covering 31 protected areas were submitted by Cape Nature; some plans cover more than one protected area “complex”. In addition, demonstration “management unit control plans” (see above) have been prepared for the upper catchment of the Berg River, and the Waterval complex, both managed by Cape Nature. South African National Parks National Parks in South Africa. 69 873 Partially adequate (49458 ha) Inadequate (20415 ha) South African National Parks reported that detailed plans for the management of biological invasions in 17 out of 22 national parks had been completed, but only three were submitted for assessment, and are reported here. Gauteng provincial reserves Six protected areas within the Gauteng Province 25 000 Partially adequate Plans were prepared for the Abe Bailey, Alice Glöckner, Leeuwfontein, Roodeplaat Dam, and Suikerbosrand Nature Reserves and the Marievale Bird Sunctuary. Municipalities Municipal management plans vary in their coverage. Some focus on protected areas within the municipal boundaries, and others on the entire municipal area. 567 329 Adequate (250 000 ha) Partially adequate (317 329 ha) Plans were submitted by the Berg River, Bitou, Buffalo City (East London), Cape Town, Ekurhuleni (Johannesburg), eThekwini (Durban), Knysna, uMdoni, and Witzenberg municipalities. 1 The MUCP software can be downloaded from a site maintained by Andrew Wannenburgh ([email protected]) of the Operational Support and Planning Directorate in the Natural Resource Management programmes of the Department of Forestry, Fisheries and the Environment (https://sites.google.com/site/wfwplanning/monitoringandevaluation). 56 Organisation Sites to be managed Area covered by plans (ha) Adequacy of plans Notes Other Government The plans submitted by large government agencies (for example Eskom and Transnet) cover some, but not all, of the land on which they operate. 371 442 Adequate (863 ha) Partially adequate (370 485 ha) Inadequate (94 ha) Plans were submitted by the Breede-Gouritz Catchment Management Agency, Denel, Eskom, Transnet, and the Maloti Drakensberg Transfrontier Conservation and Development Programme. The Greater Cape Town Water Fund Catchments of the Berg and Theewaterskloof dams, and Atlantis aquifer, Western Cape Province 0 NA Plans were not received and so the adequacy of the system has not yet been assessed. The GCTWF has developed a decision support system which guides management decisions based on ongoing monitoring of progress towards goals. Private landowners Six plans were submitted by privatelyowned companies or individuals 19 856 Adequate (4 ha) Partially adequate (19 852 ha) A demonstration management unit control plan was also been developed in 2016 for the Greater Simonsberg Conservancy near Stellenbosch, which includes 33 private landowners. The plan is no longer current. 1515 57 5.4 Output—pathways treated 1516 39 of 44 pathways are managed to some extent, and this has not changed recently. However, for more 1517 than half of these pathways, management is partial as it is focused on specific species that pose a 1518 threat to agriculture or human health, and overlooks other threats (see supplementary material S5.12). 1519 Important pathways that are still not managed include ballast water, and biofouling on aquatic vessels. 1520 South Africa is a signatory to the International Maritime Organisation (IMO), and must give effect to 1521 the International Convention for the Control and Management of Ships' Ballast Water and Sediments 1522 (BWM) through national legislation. However, there has been no progress on the draft Ballast Water 1523 Management Bill since 2017, when it was out for public comment. The BWM will have a relatively low 1524 global financial cost in comparison to other environmental policies, and if the IMO standards are 1525 implemented uniformly across the world, then the estimated costs to South Africa are low [exports 1526 are estimated to decrease by 0.01% (USD 15M), and imports by 0.03% (USD 31M)] (Wang et al. 2020). 1527 Transnet National Ports Authority had planned to implement in-water hull cleaning, however, this 1528 initiative appears to have stalled (Jacka 2021). Research has explored alternatives, including 1529 encapsulating yachts, where a structure (e.g., hull) is wrapped in plastic to deprive biofouling 1530 organisms of oxygen and food, and ultimately causing their death, though further testing is required 1531 (Keanly and Robinson 2020) before widespread implementation can be considered. 1532 There has been little change since the second report to the operations carried out by DFFE at OR Tambo 1533 International Airport, where officials perform inspections at the mail centre, the arrivals, departures, 1534 and cargo terminals, and at the private terminal, Fireblade. At the time of the second report, 1535 inspections at Fireblade had not yet commenced. Although inspections are being performed at more 1536 locations at OR Tambo, hiring and keeping officials to perform these inspections is a challenge, and the 1537 time and resources required to capacitate new officials is high. DFFE runs one joint operation with 1538 other entities per quarter, and while this assists to alleviate capacity constraints, some of these 1539 operations were cancelled in 2020/2021 to reduce the risk of officials contracting COVID-19. Between 1540 January 2020 and December 2022 DFFE performed ~ 98 000 inspections at OR Tambo International 1541 Airport, with most of these being performed at the mail centre (~ 17 000), and the arrivals (~ 64 000) 1542 and departures (~17 000) terminals (Figure S5.3). No inspections were performed between March 1543 2020 and October 2020, due to COVID-19 (Figure S5.3). Almost all the imported cargo consignments 1544 inspected (98% of ~ 260 consignments) were of Psittacula krameri (rose-ringed parakeet), with one 1545 consignment inspected for each of: Lissachatina fulica (giant African snail), Morelia spilota (diamond 1546 python), Oreochromis niloticus (Nile tilapia), and Hydrochoerus hydrochaeris (capybara). These taxa 1547 are all regulated under the NEM:BA A&IS Regulations [see Appendix 2 and Wilson (2023) for details]. 1548 58 Inspections of imported plants, animals, and their products for agricultural threats are performed by 1549 DALRRD at various ports of entry and other sites (e.g., National Plant and Plant Product Inspection 1550 Services regional offices). If a suspected plant pathogen or pest is found during an inspection, tests are 1551 performed for ‘quarantine pests’ by Plant Diagnostic Services. Plant diagnostic services also performs 1552 these tests on ‘audit samples’, and some imported animals and plants are also kept under quarantine 1553 while further tests are done. ‘Quarantine pests’ are those that have been assessed through a pest risk 1554 analysis, have been deemed to pose an unacceptable risk to agriculture, and are prohibited from 1555 entering the country. Over the period from 1 April to 31 December 2022, DALRRD performed ~14 000 1556 inspections of animal/animal product imports, ~67 000 inspections of plants/plant product imports, 1557 and ~50 000 inspections of phytosanitary certificates. The vast majority of these inspections (90% of 1558 the animal imports, 85% of the plant imports, and 100% of the phytosanitary certificates) were of 1559 imports for commercial purposes. In addition, 286 plant and 966 animal imports were placed in 1560 quarantine for further testing, and Plant Diagnostic Services performed over 9 000 tests on over 4 000 1561 samples. In this report information on the at-border inspections, and related activities, by DALRRD is 1562 reported for 2022 only, as DALRRD was unable to supply the information for 2020 and 2021. 1563 The Border Management Authority, which was established through the Border Management Authority 1564 Act of 2020, and which will be fully operational in 2023, is an important development in the 1565 management of pathways. In previous reports, it was highlighted that South Africa’s uncoordinated 1566 approach to border management was likely costly and ineffective, and that species that pose 1567 environmental threats were likely to be overlooked at ports of entry where inspections largely focus 1568 on agricultural pests or animal and human diseases (van Wilgen and Wilson 2018, Zengeya and Wilson 1569 2020). The BMA intends to be the single authority for the management of South Africa’s borders, 1570 integrating and co-ordinating the functions currently performed by various government departments 1571 at ports of entry, including those performed by DFFE and DALRRD. This promises to be an improvement 1572 on the current approach which comprises multiple authorities with different mandates. 1573 5.5 Output—species treated 1574 Based on submissions received, 196 of the 559 regulated taxa received some management treatment 1575 during 2020–2022 (Table 5.5). In terms of alien agricultural pest species, 39 are controlled by 48 1576 established biological control agents, although only one of these pest species [Pseudococcus 1577 calceolariae (the scarlet mealybug)] is listed under the NEM:BA A&IS Regulations. 1578 During 2020–2022, 48 alien plant biological control agents were actively managed to increase their 1579 abundance or extent (e.g., through mass rearing, re-release, or distribution to new areas, see Table 1580 65 economically justifiable, but the cost of fully restoring ecosystem structure, functioning, and 1749 composition in highly degraded ecosystems has rarely been deemed economically justifiable in South 1750 Africa (Holmes et al. 2020; van Wilgen et al. 2022). Generally, government-supported control 1751 operations have not included restoration efforts, at least in part because there is little or no funding 1752 for implementing active restoration projects at the necessary scale—most sites are left for passive 1753 restoration (van Wilgen et al. 2022). 1754 1755 66 Box 5.1 The regulation of invasive species used in commercial timber plantations 1756 One of the major sources of plant invasions in South Africa is the spreading of invasive trees from 1757 commercial timber plantations, which is ongoing despite the forestry sector being heavily regulated. 1758 Several tree species used in plantations in South Africa have been listed as invasive species under the 1759 National Environmental Management: Biodiversity Act, 2004 (Act No. 10 of 2004)’s (NEM:BA) Alien 1760 and Invasive Species Regulations of 2020 (A&IS Regulations). In terms of the A&IS Regulations, a 1761 permit is required to establish a new plantation or to extend an existing plantation involving those 1762 species [see Appendix 6 for the permits issued per taxon, and Wilson (2023) for details of the listed 1763 taxa]. Importantly, the Minister of Forestry, Fisheries and the Environment has, in terms of NEM:BA, 1764 exempted existing plantations—those plantations that were established and operational before 1 1765 August 2014, when the A&IS Regulations first came into operation—from the requirement to obtain 1766 a permit in terms of NEM:BA and the A&IS Regulations. 1767 One of the prerequisites for a permit for a restricted activity involving an invasive species is that the 1768 applicant must have demonstrated that adequate measures will be taken to prevent the spread of 1769 the relevant invasive species. The A&IS Regulations also provide for compulsory conditions in these 1770 permits, including that the holder of the permit must be required to take all necessary steps to 1771 prevent the escape and spread of the species. 1772 NEM:BA permits are not the only regulatory tool relevant for plantations. Additional regulatory 1773 requirements for plantation forestry include: 1774 • A water use licence (WUL) in terms of the National Water Act, 1998 (Act No. 36 of 1998) 1775 (NWA) for any “stream flow reduction activities,” which includes the use of land for 1776 commercial afforestation; 1777 • Environmental authorisation for a plantation exceeding 300 ha in extent in terms of the 1778 National Environmental Management Act, 1998 (Act No. 107 of 1998) (NEMA); 1779 • A licence to establish or recommission a plantation in a State Forest in terms of the National 1780 Forests Act, 1998 (Act No. 84 of 1994) (NFA); and 1781 • Consent from the relevant authorities to grow specified invasive plant species in areas other 1782 than those identified in WULs or other specifically demarcated areas in terms of the 1783 Conservation of Agricultural Resources Act, 1983 (Act No. 43 of 1983) (CARA). 1784 The additional regulatory approvals above may be subject to appropriate conditions, but unlike the 1785 permits issued under the A&IS Regulations, they do not require the operators to prevent the spread 1786 of the invasive species beyond the approved area. This may well become problematic in the case of 1787 67 existing plantations (those established before 1 August 2014) for which permits issued under the 1788 A&IS Regulations are not required. 1789 While there is a general duty to eradicate or control listed invasive species in NEM:BA, that 1790 responsibility only applies to owners of land on which the invasive species is present. Commercial 1791 forestry companies that operate existing commercial plantations (those established before 1 August 1792 2014) in State Forests (owned by the State) therefore do not have that general duty of care. In those 1793 instances, the State bears the duty of care. 1794 Evidentiary proof that invasive plants have spread from a particular property is often also difficult to 1795 obtain, especially where there are multiple plantations in an area. 1796 Thus, despite the multitude of legislation that applies to commercial forestry in South Africa, forestry 1797 operators managing plantations established before 1 August 2014 in State Forests do not have the 1798 responsibility to prevent the spread of the invasive trees to neighbouring properties and beyond. In 1799 those instances, the State bears that responsibility. In cases where commercial operators are 1800 required in terms of permits issued under the A&IS Regulations to prevent the spread of invasive 1801 species to neighbouring properties and beyond, it is also difficult to enforce given the difficulty in 1802 obtaining evidentiary proof of the origin of invasive specimens. Thus, a substantial area of 1803 commercial forestry remains as an unregulated seed source for re-invading adjacent areas that have 1804 been cleared. 1805 1806 Box Figure 5.1. Forestry plantations (background) are a major and ongoing source of propagules for 1807 invading adjacent areas (foreground). Photo: Brian van Wilgen. 1808 1809 68 Box 5.2 The Greater Cape Town Water Fund 1810 Concern about the growing impact of invasive trees on Cape Town’s water supplies led to the 1811 establishment of the Greater Cape Town Water Fund in 2018. The fund was based on a feasibility 1812 study (Turpie et al. 2017) and business case (Stafford et al. 2018) which showed that clearing Cape 1813 Town’s priority water catchments by removing invasive trees could generate annual water gains of 1814 50 billion litres within five years—equivalent to one-sixth of the city’s current supply needs. These 1815 gains could double to 100 billion litres annually within 30 years. This approach was estimated to be 1816 significantly more cost-effective than other water augmentation solutions. 1817 The fund is co-ordinated by the Nature Conservancy (a US-based NGO), and is a partnership between 1818 national, provincial, and local government departments, corporate sponsors (including Nedbank, 1819 Coca-Cola, AB-InBev, and REMGRO), and NGOs (the Nature Conservancy and the South African 1820 branch of the World Wide Fund for Nature). 1821 1822 Box Figure 5.2 Workers from the Greater Cape Town Water Fund removing invasive pine trees from 1823 the catchment of the Theewaterskloof dam (visible in the right-hand background). Photo: Louise 1824 Stafford. 1825 The fund has targeted the catchments of Cape Town’s major supply dams at Theewaterskloof, 1826 Bergriver, Wemmershoek, and Steenbras, as well as the recharge basin of the Atlantis aquifer (Box 1827 Figure 5.1). The fund has a blended funding model and a 30-year time horizon. It has raised ZAR 182 1828 million of the required ZAR 372 million in funding for its first six years of operation, with significant 1829 contributions from corporate sponsors (28% of funds raised to date), philanthropic individuals and 1830 foundations (46%), and the City of Cape Town (26%). 1831 69 The fund’s key objective is to reduce the cover of mature alien trees to below 5% within 30 years, 1832 and restore a cover of natural vegetation where possible. The fund has already spent ~ZAR 100 1833 million, and is now half way to achieving its initial 6-year target of clearing 55 300 ha. About 75% of 1834 the cleared area was upper catchments invaded by alien pine (genus Pinus) trees. The fund uses a 1835 custom-built decision support system to guide its operations. The system tracks all clearing and 1836 follow-up operations, and prioritises sites for interventions. Interventions are also regularly 1837 monitored to assess the effectiveness of operations, as well as ecosystem recovery and social 1838 benefits generated. 1839 The implementation of this fund, which targets carefully prioritised areas, and includes the necessary 1840 components of planning and monitoring provides an exceptional example of the implementation of 1841 best practice in the control of plant invasions with clear goals and timeframes. It is also unique in that 1842 it obtains funding from multiple sources, and provides a model for the planning of similar 1843 interventions elsewhere. 1844 1845 70 Box 5.3 Successful biological control of water hyacinth on a eutrophic sub-tropical water-body 1846 Pontederia crassipes (water hyacinth) has caused Major impacts world-wide by covering water 1847 bodies in vegetation, reducing oxygen levels in the water, and thereby altering the diversity of 1848 freshwater benthic communities and impacting the provision of ecosystem services (including 1849 opportunities for fishing, and recreational opportunities such as swimming and boating). Biological 1850 control has been highly successful in tropical areas, but in more sub-tropical, eutrophic waters 1851 biological control has been less successful, especially where cooler winter climates prevail. 1852 In South Africa authorities have resorted, at considerable expense, to spraying herbicides from 1853 aircraft and boats. However, plants are able to re-colonise these sprayed areas rapidly, temporarily 1854 escaping biological control. This means that spraying operations need to be constantly repeated, 1855 adding another source of chemical pollution to the waters. 1856 A relatively new addition to the suite of biological control agents was Megamelus scutellaris, which 1857 was first released in South Africa in 2013. This insect was promising because it responds well to mass 1858 rearing, reproduces rapidly, and recovers quickly after periods of cooler temperatures. In addition, it 1859 can be exceptionally damaging to water hyacinth. Insects were mass-reared, and released in a stand-1860 alone intervention on Hartbeespoort Dam in 2018 in the absence of herbicide treatments. 1861 Following frequent inundative releases of the agents, Coetzee et al. (2022) reported that water 1862 hyacinth cover was reduced from over 37% to less than 6% over two consecutive years (Box Figure 1863 5.2). The recommendation was to release the insects often and in high numbers to inundate and 1864 overwhelm the water hyacinth and to achieve control at a fraction of the cost of herbicide 1865 applications. This represents a major breakthrough in the control of water hyacinth in South Africa 1866 (and potentially in other sub-tropical and temperate eutrophic water bodies worldwide). 1867 1868 Box Figure 5.3 Declines in the cover of water hyacinth between A) January 2017 and B) February 2020 1869 due to biocontrol by Megamelus scutellaris. Water hyacinth is the bright green against the black water 1870 in the satellite images. This control happened in the absence of herbicide applications. Figure from 1871 Coetzee et al. (2022) 1872 1873 71 5.10 Trends in interventions indicators 1874 Indicator Trend Confidence Desired trend 1 Current status and trend Outlook 12. Quality of regulatory framework → Medium ↗ The amendments to NEM:BA and the A&IS Regulations and Lists have improved the regulatory regime slightly. The law reform has clarified some concepts and one of the changes may well help the Department to prioritise where to focus scarce law enforcement interventions. However, the fundamental problems identified in the previous report have not been addressed, including the absence of a comprehensive strategy to guide implementation of the regulations and lack of flexibility in the regulatory regime. A draft national strategy on biological invasions has been developed but not, as yet, set for public comment. The recent publication of the White Paper on the ‘Conservation and Sustainable Use of South Africa’s Biodiversity’ is an indication that DFFE plans to amend NEM:BA in the near future. However, the White Paper does not address the problems with the current regulatory regime, and does not comprehensively address issues around biological invasions. The development and implementation of a national strategy for biological invasions has the potential to be a milestone in the management of biological invasions in South Africa. The development and implementation of a process to regularly and transparently update the regulatory lists informed by the best available scientific evidence is promising. 13. Money spent ↘ Low ↗2 An estimated R1.4 billion was spent between 2020 and 2022. This is an underestimate as not all government entities, NGOs or the private sector have provided estimates. However the amount spent has been declining in real terms since 2015 (van Wilgen et al. 2022). Government’s ability to fund the control of biological invasions has been reduced due to adverse economic conditions that have prevailed over the past few years. Large increases in funding are unlikely in the near future. The Greater Cape Town Water Fund may provide a new model for such fundraising (Box 5.2). 1→ no change; ↗ an increase; ↘ a decrease 2 Technically the desired value for money spent would be that estimated to be required (e.g., so that returns on investment of additional spending on average end up as zero). However, estimates of the money required to bring biological invasions under effective control suggest this figure is roughly 4.6 times greater than current budgets (van Wilgen et al. 2016). At present, if spent strategically, there are significant returns on investment to be had by spending money on controlling invasions, and therefore the desired trend is for there to be an increase in the money spent. 72 Indicator Trend Confidence Desired trend 1 Current status and trend Outlook 14. Planning coverage → Medium ↗ Pathways: 40 of the 44 pathways are assumed to have management plans in place, but these have not necessarily been formalised. No formal plans have been developed by DFFE, and there is no legal requirement to do so. There has been no change since the previous report. Species: 23 (16 listed and 7 unlisted) species have management plans in place. 13 were scored as adequate, 8 as partially adequate and 2 as inadequate. This is 2.8% of the 566 invasive species listed in the regulations. None of these plans have been formally adopted, nor is the process for formal adoption clear, although landowners are required by law to control species on their land in accordance with such plans, should they exist [NEM:BA Sections 75(4) and 75(5)]. Sites: Current management plans cover 1.6 million ha are (8.2% of the estimated invaded area). Planning coverage appears to have declined although more plans probably exist but were not submitted for assessment. Site plans that were submitted were assessed as improvements over previous plans. There is still a need to identify priority pathways, and develop and formally adopt plans to support the management of those pathways. There is a similar lack of formal planning processes to address species and sites. Without such planning it will not be possible for management to be strategic and difficult for management to be adaptive. 15. Pathways treated → Low ↗ All pathways through which alien organisms can be introduced require management, and currently 39 of the 44 pathways (89%) are managed to some extent. Most of the pathways that are managed are partially managed (51%), but many (49%) have complete management. There has been no change since the second report. The establishment of the Border Management Authority could result in more co-ordinated management of pathways. The implementation of ballast water management bill would also improve the situation. However, there is still a need to identify priority pathways, and develop pathway-focused management for those pathways. 73 Indicator Trend Confidence Desired trend 1 Current status and trend Outlook 16. Species treated → Low ↗ 196 out of 559 regulated taxa (~35%) have been subjected to some form of management. Most effort is directed towards widespread or damaging species or towards species that are potential eradication targets. Several invasive species are expanding their ranges rapidly, so capacity to deal with all species will be further reduced. The national strategy on biological invasions, in concert with the GBF (Box 1.2) is likely to incentivise greater prioritisation of control efforts against the most damaging listed invasive species, and those that present the greatest future threats 17. Sites treated Not assessed ↗ The area that has been treated 2020–2022 is estimated to be 2003 km2, this includes all land parcels that have been worked on by public works alien plant control teams. The estimated total invaded area in South Africa is 194 943 km2, so control operations have therefore reached just over 1% of the estimated invaded area. A recent study estimated that control operations between 1998 and 2020 had reached 14% of the estimated area over 22 years (van Wilgen et al. 2022). Because control operations are not followed up every year, it may be necessary to examine the extent of treatment over longer periods. There are substantial uncertainties regarding the estimated extent of invasion. Control also often does not cover the full area mapped as having received control, so the 1% (and the 14%) are probably overestimates. It is expected that the area invaded in South Africa will increase. Processes are, however, in place to ensure greater prioritisation of control efforts to ensure priority sites are cleared and kept clear (cf. outlook for 16. Species treated). 18. Effectiveness of pathway treatments → Low ↗ There has been no change to the estimated effectiveness of pathway management for most pathways. For one pathway, releases for conservation, the effectiveness of management could be estimated for the first time, and was estimated to be partially effective. Five pathways are not managed, 17 have ineffective management, one has partially effective management, six have effective management, and one has permanent management. The establishment of the Border Management Authority, and through that the co-ordination of the at-border management of pathways will hopefully improve the efficacy of at-border management. However, there is still a need to measure the efficacy of management using good data, and adapt where required. 74 Indicator Trend Confidence Desired trend 1 Current status and trend Outlook 19. Effectiveness of species treatments → Low ↗ For most of the 566 regulated taxa, there is no evidence that any management is taking place, and with the exception of species under biological control, the effectiveness of management is not known. Updated estimates will be included in the final report. Assessing the effectiveness of species treatments at a national scale is based on changes in the size of the population (for animals) or the extent of invasion (for plants). These are currently not monitored except for some alien plants that are the target of biological control. The absence of a reliable baseline and regular updates will continue to prevent accurate assessments of control effectiveness, especially at a national scale. When assessed at finer scales, there are examples of partially effective treatments of species at some sites. 20. Effectiveness of site treatments Not assessed The paucity of management plans with clear goals and regular monitoring of those plans makes it difficult to assess effectiveness, which would have to be expressed in terms of progress towards achieving the goal. For some areas where information is available, there are indications that some interventions are at least partially effective, but the goals of management are typically unstated, making such assessments difficult. There is no information to suggest that the situation has changed since the second report. There are almost no routinely-collected data to assess the effectiveness of site treatments, either in terms of changes in the extent of the area invaded, or in terms of ecosystem recovery following control. Accurate assessments are only possible for small areas that have been the subject of research studies. High-level indicator D. Level of success in managing invasions Not assessed This indictor cannot be calculated as there are very few data on the effectiveness of control of invasions at specific sites. Making a reasonably accurate assessment of the overall success of managing invasions remains challenging due to the paucity of stated goals in management plans against which to assess progress, as well as the scarcity of activities to regularly monitor progress towards goals. As reported in the second report, these issues need to be urgently addressed, because without them effectiveness cannot be known, management cannot be adaptive, and the impacts and costs of invasions will continue to rise. The proposed national strategy and action plan on biological invasions may help explicitly address these issues. 1875 81 that the unaided pathway is important for alien plants on the islands; we suspect that this is a common 2026 pathway of dispersal for alien species. On Marion Island, it is thought that Sagina procumbens was 2027 spread from the research base by helicopter during annual restocking of the huts (Gremmen and Smith 2028 1999). The construction of a steel helicopter pad at the new research base has likely reduced dispersal 2029 through this pathway, although the helicopter still lands on vegetation at the huts and so might still 2030 be responsible for spreading propagules. It is likely that some propagules are spread by field workers, 2031 but this has not been investigated. 2032 Table 6.2. The within-country pathways by which alien species are known, or strongly suspected, to 2033 spread on the Prince Edward Islands. Pathways not depicted are not present, highlighting the low 2034 number of possible pathways available within the islands. 2035 Pathway category & subcategory Within-country pathway prominence Examples of within-country dispersal Transportstowaway: People/equipment Not known It is assumed that this is an important pathway on Marion Island, but it has not been specifically monitored except for Lee and Chown (2011) who found 420 seeds carried on 225 different clothes items on expeditioners that were returning to mainland from Marion Island, and could have potentially spread those propagules within the island (at least three seed were of highly invasive plant species). Transportstowaway: Container and bulk cargo Minor Sagina procumbens was possibly spread across the island during hut restocking, when containers are dropped at huts by helicopter. This happens once a year. Other plants could have been spread by this means too. The invasive slug Deroceras panormitanum has been spread around Marion Island through wooden crates that are packed around the research station prior to aircraft and ship operations (Chown et al. 2002). Unaided Moderate Several plant species have spread over fairly large distances on Prince Edward Island during a time when no humans visited the island. It can be expected that most increases in the range of invasive species on Marion Island are similarly unaided. 2036 6.2 Species 2037 6.2.1. Number and status of alien species 2038 Seventy-five alien taxa have been recorded at some point on the PEIs, two taxa are recorded as 2039 cryptogenic (i.e., nativity has not been confirmed)1, and one plant, Ochetophila trinervis, is thought to 2040 have arrived unaided via vagrant birds from South America since humans first arrived on the island 2041 (Kalwij et al. 2019), as so is considered native (Appendix 7). Out of the 75 alien taxa ever recorded, 43 2042 1an unidentified mite species from the family Cillibidae was first recorded from Marion Island during 1996 or 1997 (Marshall et al. 1999). This family had not previously been recorded in the sub-Antarctic and this species was considered “likely” an introduced species (Marshall et al. 1999). However, since this initial collection no progress has been made in determining the identity or status of the species, despite it frequently being the numerically dominant mite species in some habitats (see e.g., Barendse et al. 2002). 82 are still present, the presence of five taxa is doubtful until eradication is confirmed, and the remaining 2043 27 are no longer present. There are currently no alien taxa in captivity nor under cultivation. Of the 2044 43 alien taxa currently present, 24 are invasive, 11 are naturalised but not invasive, two are present 2045 but not naturalised, and six cannot be assigned to one of the basic introduction status categories (i.e., 2046 it is unclear if they are naturalised, invasive, or neither) (Figure 6.3). Therefore, more than half of the 2047 alien taxa present on the PEIs are invasive. Of the 24 invasive taxa, 17 are invertebrates, five are plants, 2048 one is a fungus, and one is a mammal; there are no alien birds, reptiles or amphibians (see Section 2049 S6.2). All alien taxa are either terrestrial or freshwater species, as, despite an active search, no marine 2050 alien species have been detected to date (Greve et al. 2020). 2051 2052 Figure 6.3 The status of alien taxa introduced to the Prince Edward Islands (PEIs) as per the Unified 2053 Framework (Blackburn et al. 2011), including species that were present but are no longer (A1), see 2054 supplementary material S6.2 for a break-down into functional groups. The introduction status of six 2055 taxa is not known and these are not shown on this figure. 2056 6.2.2. Extent of alien species 2057 Distribution data were available for all but one alien taxon on the PEIs. For Bakerdania sp. (Acari), it is 2058 unclear if the taxon is present on Prince Edward Island. 2059 Estimates from a 2008 study suggested that less than 5% of the PEIs had been covered by alien plants 2060 (Gremmen and Smith 2008). In a more recent study, le Roux et al. (2013) determined that alien plant 2061 species were present in 42% of Marion Island’s half minute grid cells (hmgcs are ~0.59 km2, roughly 2062 926 m by 635 m), and in 53% of Prince Edward Island’s hmgcs. Sagina procumbens (166 hmgcs), Poa 2063 annua (204 hmgcs) and Cerastium fontanum (162 hmgcs) are the most widespread species on both 2064 islands (DFFE 2010, le Roux et al. 2013, Mairal et al. 2022). Sagina procumbens and C. fontanum 2065 together with invasive springtails (Ceratophysella denticulata, Megalothorax minimus and 2066 83 Pogonognathellus flavescens) have increased their distribution along the cooler regions due to rising 2067 temperatures associated with climate change (Kgopong 2019). For occupancy details of each species, 2068 see Appendix 7. 2069 The ECOs at Marion Island have started to map the extent of invasions, and to create polygon maps 2070 to assess progress on plant control measures. DFFE provided data for three species, Agrostis gigantea 2071 (1.39 ha), Rumex acetosella (0.1 ha) and Luzula multiflora (1.2 ha) (see maps in supplementary 2072 material S6.3). 2073 6.2.3. Abundance of alien species 2074 Greve and le Roux have unpublished data from transects comprised by quadrats sampled at 2075 intervals, where they assessed plant cover: native plants had the highest percentage cover (54.6%), 2076 followed by bare ground/rocks (42.8%) and lastly alien plant cover (2.6%). From the alien plant 2077 cover, Sagina procumbens had the highest abundance (0.9%), followed by Poa annua (0.39%), 2078 Agrostis stolonifera (0.1%), Cerastium fontanum (0.07%) and Poa pratensis (0.04%). These values, 2079 however, could be currently lower due to ongoing management actions. 2080 The abundance of alien (and cryptogenic) invertebrates has been assessed for different taxonomic 2081 groups [e.g., springtails (Collembola), mites (Acari)], and the data is presented as individuals per 2082 square metre in different vegetation types or habitats (Barendse et al. 2002, Hugo et al. 2006, 2083 Treasure et al. 2019, Chown et al. 2022). In some studies, more detail is provided (e.g., life stage, 2084 sex; Khoza et al. 2005), but there have been no estimates for ‘exact overall number’ on any of the 2085 PEIs. For both islands, the alien (and cryptogenic) abundance of invertebrates varied strongly 2086 between habitat types and, for Marion Island, along the altitudinal gradient (Figure 6.4, 2087 supplementary material S6.4). For Marion Island, alien springtails were more abundant on the mire 2088 characterised by Sanionia uncinata (40 380 individuals/m2), and mites were more abundant in the 2089 salt-spray vegetation formed by the native Cotula plumosa (2 623 individuals/m2) (Figure 6.4). 2090 Similarly, on Prince Edward Island the salt-spray vegetation type of C. plumosa was the most 2091 common habitat for mites (15 039 individuals/m2), although for springtails the highest abundance 2092 was found on slopes covered by the native Blechnum penna-marina (234 individuals/m2). 2093 The highest density of mice on the island was 231.8 mice/ha between 2008–2011, with a total 2094 number of individuals estimated at 1 760 740 (McLelland et al. 2018). Mice density increased by 2095 430.0% between 1979–1980 and 2008–2011 (McLelland et al. 2018). 2096 84 2097 2098 Figure 6.4. Abundance of a) alien springtails on Prince Edward Island, b) alien springtails on Marion 2099 Island, c) cryptogenic mites on Prince Edward Island, and d) cryptogenic mites on Marion Island, in 2100 terms of individuals per square metre. Labels on the x-axis indicate vegetation type and, where 2101 appropriate, the plant species or the altitude sampled within the vegetation type. Note that the y-axis 2102 limits differ between panels. Biotic: Poa = Biotic grassland and herbfield (Poa cookii); Azorella = 2103 Azorella selago; Salt-spray = Coastal salt-spray; Cotula = Cotula plumosa; Crassula = Crassula 2104 moschata; Acaena = Acaena magellanica; Blechnum = Blechnum penna-marina; Blephar = 2105 Blepharidophyllum densifolium; high-alt = high-altitude; James = Jamesoniella colorata; mid-alt = mid-2106 altitude; Sanionia = Sanionia uncinata. 2107 6.2.4. Impact of alien species 2108 Of the 20 taxa assessed with data from the PEIs using the EICAT scheme, one had a Massive impact 2109 (house mouse) and four had Major impacts (Table 6.3, see Supplementary Material S6.2 for the 2110 approach taken). The impacts of individual invasive taxa have been quantified in a number of cases 2111 for Marion Island: e.g., for the now eradicated Felis catus (van Rensburg and Bester 1988; Hunter 2112 1990), for Mus musculus (Crafford 1990; Jones et al. 2019), and for the grass Agrostis stolonifera 2113 (Gremmen 1997, Gremmen et al. 1998). Even though no EICAT assessments have been formally 2114 undertaken and reviewed for the PEIs, seven species (four currently present) possess a global 2115 85 published EICAT assessment (three plant species have a Moderate impact and the house mouse a 2116 Massive impact). 2117 Table 6.3 The number of alien taxa with different levels of recorded environmental impact on the 2118 Prince Edward Islands (PEIs). Taxa were assigned to various categories of impact based only on studies 2119 from the PEIs (Greve et al. 2017), and not based on global EICAT assessments. 2120 Taxon Environmental Impact (~EICAT) Data Deficient Minimal Minor Moderate Major Massive Mammals 0 0 0 0 0 1 Microbial species 0 0 0 1 0 0 Terrestrial and freshwater plants 1 3 2 2 4 0 Terrestrial invertebrates 22 0 5 1 0 0 2121 The greatest recorded impacts were associated with the house mouse. The house mouse is fortunately 2122 only present on Marion Island, but it has had impacts at the ecosystem- (Crafford 1990) and species-2123 levels, affecting the island’s only shorebird (Huyser et al. 2000), seabirds (Jones et al. 2019, Jones and 2124 Ryan 2010, Dilley et al. 2017), native vegetation (Phiri et al. 2009), and invertebrates (van Aarde et al. 2125 2004). The house mouse has had negative impacts on plant species survival (Azorella selago; Phiri et 2126 al. 2009) and reproduction (Uncinia compacta; Chown and Smith 1993), invertebrate abundance, 2127 biomass and body size (Chown and Smith 1993; Crafford and Scholtz 1987; Treasure and Chown 2014; 2128 McClelland et al. 2018), and albatross chick survival (Jones and Ryan 2010, Dilley et al. 2017). House 2129 mouse burrowing also alters sediment movement rates (Eriksson and Eldridge 2014), and likely 2130 impacts on nutrient cycling (Crafford 1990; Smith and Steenkamp 1990). Evidence shows that there 2131 has been a shift in mouse behaviour with predation on seabirds’ chicks increasing over time, and 2132 recent records of mice attacking adult seabirds (Jones et al. 2019). Arguably such a behavioural shift 2133 means the impact of mice has recently increased markedly, emphasising the importance of achieving 2134 eradication soon. 2135 Various plants, including the grass Agrostis stolonifera, have had Major impacts on native vegetation 2136 and soil fauna communities (Gremmen 1997, Gremmen et al. 1998). Very little has been documented 2137 on the impacts of terrestrial invertebrates. Lastly, the fungal ascomycete Botryotinia fuckeliana was 2138 found to significantly affect the distribution and abundance of a native plant species (Kloppers and 2139 Smith 1998). 2140 6.3 Sites 2141 6.3.1. Alien species richness 2142 86 Alien plant species richness is highest close to the Marion Island base and meteorological station, and 2143 high along the northern and eastern coastal areas, particularly in areas with current or historic 2144 anthropogenic disturbances (e.g., research field huts; le Roux et al. 2013). The highest alien plant 2145 richness at the hmgc-scale was eight species (at the research station). Alien plant richness on Prince 2146 Edward Island is more evenly spread across the island, with the highest richness along the coast and 2147 the steep escarpment on the north-western side of the island [maximum alien plant species richness 2148 at the hmgc-scale was three species; le Roux et al. (2013)]. 2149 6.3.2. Relative invasive abundance 2150 The mean cover of all invasive plant species is 2.6% on Marion Island (Greve unpublished data). This 2151 estimate is based on 501 plots of 3 x 3 m that are spread across the island. Given that these plots cover 2152 only a small percentage of the island, confidence in this estimate is low. There is spatial variation in 2153 the relative invasive abundance across Marion Island. Coastal habitats are generally more invaded 2154 than inland habitats. There is no data available on the relative abundance of alien plants for Prince 2155 Edward Island. 2156 For both islands, the relative invasive abundance of invertebrates varied strongly between habitat 2157 types and, for Marion Island, along the altitudinal gradient (Figure 6.5). Springtails are relatively well 2158 surveyed, and have a relative invasive abundance that varies between 0 and 2% on Prince Edward 2159 Island and between 0 and 90% on Marion Island (mean relative abundance = 28%; Treasure et al. 2019, 2160 Chown et al. 2022). The relative invasive abundance of springtails is highest at lower altitudes, and in 2161 bryophyteand fern-dominated vegetation types. Spiders have only been adequately sampled on 2162 Marion Island (and only from five locations on the eastern side of the island) to document relative 2163 invasive abundance, and data shows relative invasive abundance varying from 0–98% (mean = 37%; 2164 Khoza et al. 2005). The relative abundance of alien spiders was lowest at the two sites with the highest 2165 elevation on the island. Alien mites comprise 0–26% of all mites on Prince Edward Island (mean = 8%; 2166 Hugo et al. 2006) and 3–28 % of mites on Marion Island (mean = 14%; Barendse et al. 2002). However, 2167 due to uncertainty regarding the identity (and status) of Cillibidae sp. nov., which comprises c. 95–2168 100% of the alien mite individuals sampled from the islands, there is considerable uncertainty in these 2169 estimates. Relative invasive abundance of Isopoda is 100% due to the absence of native isopods. 2170 Relative abundance data for some taxa (e.g., Insecta) are not available due to the lack of complete 2171 surveys (i.e. not all species within the taxon recorded during sampling). 2172 87 2173 2174 Figure 6.5. Relative abundance of alien a) springtails on Prince Edward Island, b) springtails on Marion 2175 Island, c) mites on Prince Edward Island, and d) mites on Marion Island. Labels on the x-axis indicate 2176 vegetation type and, where appropriate, the plant species or the altitude sampled within the 2177 vegetation type. Note that the y-axis limits differ between panels. Biotic: Poa = Biotic grassland and 2178 herbfield (Poa cookii); Azorella = Azorella selago; Salt-spray = Coastal salt-spray; Cotula = Cotula 2179 plumosa; Crassula = Crassula moschata; Acaena = Acaena magellanica; Blechnum = Blechnum penna-2180 marina; Blephar = Blepharidophyllum densifolium; high-alt = high-altitude; James = Jamesoniella 2181 colorata; mid-alt = mid-altitude; Sanionia = Sanionia uncinata. 2182 6.3.3. Impact of invasions 2183 Gremmen (1997) estimated that invasion by grasses (plots dominated by Agrostis stolonifera but with 2184 presence of other aliens) led to a 50% decrease in native vegetation richness in invaded drainage lines. 2185 Bryophyte biomass was also 16 times lower in these habitats, but the species richness of 2186 macroinvertebrates and mites was higher in invaded areas (Gremmen et al. 1998). A comparison of 2187 Marion and Prince Edward Island with the uninvaded Heard Island showed that invasive springtails 2188 caused at least a four-fold decline in average on the density of three native springtail species (Chown 2189 et al. 2022), but Gabriel et al. (2001) did not find a negative impact of invasive springtails on either the 2190 richness or abundance of native springtails across 13 habitats on Marion Island. 2191 88 6.4 Interventions 2192 6.4.1. Input—quality of regulatory framework 2193 The PEIs have the highest level of protection afforded to any natural area under South African law. 2194 The islands were declared a Special Nature Reserve in 1995 and are reserved primarily for scientific 2195 research and environmental monitoring (DFFE 2010). Recreation activities are prohibited. The PEIs 2196 were designated a Ramsar Wetland Site of International Importance in 2007, and in 2013, the Prince 2197 Edward Island Marine Protected Area was formally declared (DFFE 2010). Alien species are not allowed 2198 to be introduced to the PEIs. 2199 The NEM:BA A&IS Regulations (2020) list 13 of the 48 taxa currently present (or doubtful) on the 2200 islands, but two taxa which are being managed are not currently listed and four taxa which are listed 2201 (and therefore should be managed) are not being managed (Table 6.4). None of the species currently 2202 regulated for the PEIs are regulated for mainland South Africa. No risk analyses have been performed 2203 for taxa listed on the PEIs (Table S5.2), and, given that ideally the PEIs should be alien-free, arguably 2204 it is inappropriate for risk analyses to be conducted solely for the PEIs. An evaluation of management 2205 options conducted and regularly updated within the scope of the PEIs Management Plan would likely 2206 provide the necessary and sufficient information to guide interventions. 2207 Table 6.4. Alien taxa listed under the NEM:BA A&IS Regulations of 2020 for the Prince Edward Islands 2208 (PEIs) or for which an eradication plan has been developed [cf. Appendix 7; Wilson (2023)]. Only the 2209 listing relevant to the PEIs is included here. Information on the implemented control measure was 2210 obtained mainly from the Department of Environmental Affairs (DEA) and DST-NRF CIB 2012–2013, 2211 last updated in 2021, personal communication with DFFE Specialist Programme Manager Debbie Muir, 2212 or indicated otherwise. Technically as the PEIs are off-shore islands, the following are also listed as 1b 2213 [Alectoris chukar (Chukar partridge), Oryctolagus cuniculus (the European rabbit), Rattus norvegicus, 2214 R. rattus, and R. tanezumi (the Norwegian, brown, and Asian house rat respectively)] and the following 2215 as 1a [Capra hircus (goat) and Felis catus (domestic cat)]. 2216 Scientific name Vernacular name Regulatory listing Introduction Status Treated or monitored Notes on control implemented Agrostis castellana bent grass 1a PEI 1b MI Present but not naturalised Yes Inflorescences are cut and bagged, and the remaining parts of the plants sprayed with herbicide (Debbie Muir pers. comm. 22 May 2023) Agrostis gigantea black bent grass 1a Naturalised but not invasive Yes Mechanical removal of aboveground biomass and herbicide application (Glyphosate; 2.5% Kilo Max) Agrostis stolonifera creeping bent grass 1a PEI 1b MI Invasive No None implemented (successful eradication deemed unfeasible; Greve et al. 2017) 89 Scientific name Vernacular name Regulatory listing Introduction Status Treated or monitored Notes on control implemented Alopecurus geniculatus marsh foxtail 1a Doubtful (eradication to be confirmed) Yes Manual removal was applied, assumed to be no longer present since 2012 (Greve et al. 2017) Cerastium fontanum common mouse-ear chickweed 1b Invasive No None implemented because it is widespread (Greve et al. 2017, DEA and DST-NRF CIB 2021) Elymus repens 1 couch grass 1a Naturalised not invasive Yes Mechanical removal of aboveground biomass and herbicide application (Glyphosate; 2.5% Kilo Max 700g/kg) Festuca rubra creeping red fescue 1a Naturalised not invasive Yes Herbicide application (Glyphosate; 2.5 Kilo Max) Holcus lanatus common velvet grass Not listed Doubtful (eradication to be confirmed) Yes The species was manually removed in 2012, site and surrounding areas have been monitored monthly since removal to detect any regrowth or new plants Luzula multiflora woodrush 1a Naturalised not invasive Yes Herbicide application (Glyphosate; 2.5% Kilo Max). A genetic study has been recommended to confirm that it differs from the native subantarctic Luzula species (and so unequivocally alien) Mus musculus house mouse 1a MI Invasive Yes Baited traps are deployed both outside and inside the base and huts to protect food and human health (Wolfaardt pers. comm. 2022). Mice are not yet, otherwise, subject to control, although an eradication is being planned, namely the ‘Mouse-free Marion Project’ due to start in 2025 if enough funds are raised Poa pratensis Kentucky bluegrass 1a PEI 1b MI Invasive No None implemented (Greve et al. 2017, DEA and DST-NRF CIB 2021) Porcellio scaber Common rough woodlouse Not listed Doubtful (eradication to be confirmed) Yes The woodlouse is believed to have been successfully eradicated in 2012, but this needs to be monitored for confirmation. Eradication is recommended via application of pyrethroid (Super Crackdown) 1Listed as Elytrigia repens (L.) Desv. ex Nevski (= Agropyron repens (L.) P. Beauv., Elymus repens (L.) Gould) under the A&IS Regulations of 2020. 90 Scientific name Vernacular name Regulatory listing Introduction Status Treated or monitored Notes on control implemented Rumex acetosella Sheep sorrel 1a Naturalised not invasive Yes Mechanical removal of aboveground biomass with no herbicide application (inflorescence is cut and then plant pulled) (Debbie Muir pers. comm. 22 May 2023) Sagina procumbens Birdeye pearlwort 1b Invasive No None implemented (successful eradication deemed unfeasible by Greve et al. 2017), but the potential for classical biocontrol is under investigation. Stellaria media Common chickweed 1a PEI 1b MI Doubtful Yes Herbicide application (2.5% Kilo Max). 2217 6.4.2. Input—money spent 2218 Given the discrete nature of the PEIs and the limited number of people involved, it should be possible 2219 to estimate the money spent to control invasions. However, no such estimates have been made yet, 2220 in part as information has not been forthcoming. The following information is available. The DFFE 2221 budget for herbicides (two different types) and equipment, including personal protective equipment, 2222 for the control of alien species on the PEIs 2011–2022 was ZAR 58 664 (see supplementary material 2223 S6.5). The only pesticide applied on Marion Island to control invertebrates was donated; the value of 2224 this has not yet been obtained. In 2006 there was a specific targeted effort to control the invasive 2225 plant Elymus repens, where above-ground material and some of the below-ground rhizomes were 2226 removed, and herbicide was applied. The total cost of the operation was ZAR 201 378 which included 2227 human resources as well as helicopter trips to transport the removed biomass. 2228 The major cost controlling biological invasions on Marion island will be the time of the ECOs. ECOs 2229 perform various duties, but there is no current estimate available of the time allocated to alien species 2230 monitoring and control. No continuous control (or monitoring) is possible on Prince Edward Island due 2231 to the lack of regular human presence on the island. 2232 6.4.3. Input—planning coverage 2233 The current management plan determines the quarantine and biosecurity measures to be applied to 2234 introduction pathways, and makes recommendations for the management of invasive species. The 2235 PEIs Management Plan includes both islands, and so all sites have a management plan in place. 2236 There have been two management plans developed for the PEIs: one published in 1996, and another 2237 in 2010 (Version 0.2). The second plan was officially adopted by the then Department of 2238 Environmental Affairs (DEA) in 2014. Management plans were set to be revised and updated every 2239 97 Indicator Trend1 Confidence Desired trend Current status and trend Outlook 10. Relative invasive abundance ↗ low ↘ Mean plant cover on MI 2.6%; no plants data for this indicator on PEI. Invertebrates’ relative invasive abundance varies between 0–2% for PEI springtails to 28% on MI; for mites between 8% at PEI and 14% at MI; however, the uncertainty of nativity status for Cillibidae make this estimate very low confidence. Spiders have been studied only on MI (37% mean relative abundance) and there is no data for insects due to lack of complete surveys. Expected to increase as species spread across larger extents of the island, increasing islandwide impacts; but also expected to increase as climate amelioration may make the environment more favourable for generalist invaders. 11. Impact of invasions ↗ low ↘ Because abundance is increasing, and because there are some indications that the amelioration of climate on the PEIs is benefitting invasive over native species, the impact is assumed to increase. Little data. (Mice have increased populations, McClelland et al. 2018). Expected to increase as species spread across larger extents of the island, increasing islandwide impacts; but also expected to increase as climate amelioration may make the environment more favourable for generalist invaders. 12. Quality of regulatory framework ↗ high ↗ The current management plan was developed in 2010. The eradication plan is revised and updated every year. The quality of the regulatory framework is considered partial. Regulations are in the process of being revised and a new Management Plan is meant to go out for public comment in 2023. The process of prioritising management targets will likely be more effective if decoupled from national-level regulations and processes. 13. Money spent ↗ medium ↗ The DFFE budget for herbicides and equipment for the control of alien species on the PEIs during 2011–2022 was ZAR 58 664. This is an underestimate, as a full value was not provided. For example, the cost of hours invested by ECOs on control of alien species has not been estimated. A reduction in total costs of invasive clearing is expected in line with the Invasive Alien Species management plan. Significant funds will be spent in a short period of time if the Mouse-Free Marion Project is implemented. 14. Planning coverage ↗ high ↗ All seven active pathways have management plans in place. Alien invasive species management plan compliant to NEMBA regulations Section 76 (A), Section 70 (1)(2)(3). The management plan covers Marion and Prince Edward Island, so all sites have a management plan in place, although outdated. Eradication plan to be updated after second party assessment (April/May 2023) to include historical and active species sites. A mapping system that can reflect historical and active control methods will be available. Mapping system can be used for estimating increase or decrease on invasions potential, allowing for adaptive management and update of eradication plans. 98 Indicator Trend1 Confidence Desired trend Current status and trend Outlook 15. Pathways treated → high ↗ All pathways by which alien species can be introduced require management, and they are all being managed under strict biosecurity measures. Information on biosecurity breaches (e.g., identifications) can be used to improve protocols. 16. Species treated ↘ high ↗ Of the 13 listed invasive taxa (12 plant species and one mammal), 8 plants are subjected to some form of management (either inflorescence cut and bagged and plant pulled, or herbicide). Five potentially eradicated species are being monitored to confirm status (four plant species and the isopod). Mice are only controlled at the base and huts. Invasive plants’ historical sites and active sites are being mapped and monitored. Confirmation of eradication for five species will only be done if they have not been seen for four consecutive second party assessments (12 years). If the Mouse Free Marion eradication plan goes ahead in 2025 a contingency plan after mass baiting must be implemented. 17. Sites treated → high ↗ Marion Island is treated on a regular basis, however Prince Edward Island can only be visited every four years (but has not been visited in the last 10 years), therefore there is no management currently applied on that site. Mapping and monitoring plan will indicate historical as well as active sites to indicate effectiveness of control plans. 18. Effectiveness of pathway treatments Not assesse d ↗ The necessary quantitative data to assess this indicator are not available. Information on biosecurity breaches (e.g., identifications) can be used to improve protocols. 19. Effectiveness of species treatments ↗ high ↗ Many invasive species are subject to some form of control, and outcomes are monitored. There are 11 taxa that are eradication targets, with five that are potentially eradicated and have become monitoring targets as they have not been seen for several consecutive years. DFFE three-year assessment results indicate a reduction in active sites. Four widespread invasive plant species are considered inappropriate targets for eradication, and therefore are not being treated. Mapping and monitoring program will indicate effectiveness of control programmes in future. New control technologies will likely be needed if current widespread invasive taxa other than the house mouse are to be effectively controlled. 20. Effectiveness of site treatments ↗ high ↗ Second party assessment implemented threeyearly at Marion Island to quantify effectiveness of treatments and possible reductions of taxa populations (plants, isopod and mice). Monitoring plan data will be used to amend / update invasive species management plan. 99 Indicator Trend1 Confidence Desired trend Current status and trend Outlook A. Rate of unregulated introduction of new species → medium ↘ The rate of introduction has not changed in the last ten years. No change is envisaged. Traffic to, and pathways to the islands is not expected to change because the same protocol is strictly followed every year and is unlikely to change in the near future. Recent improvements (e.g., no Velcro) and continuing work on biosecurity would be needed if the goal of zero introductions is to be achieved. B. Number of invasive species that have Major impacts → medium ↘ No new invasive species have been introduced to the islands recently, although existing invaders are spreading and their impacts might have increased. Expectation is that current range restricted taxa will not be allowed to spread, and so any changes to this will be in terms of existing widespread invaders increasing in terms of the impacts they cause over time. C. Extent of area that suffers major impacts from invasions ↗ ↘ Several alien species have not reached equilibrium with the environment across the PEIs and are still spreading. Some of these have Major impacts (e.g., Sagina procumbens). Expected to increase as species spread across larger extents of the island, increasing islandwide impacts; but also expected to increase as climate amelioration may make the environment more favourable for generalist invaders. D. Level of success in managing invasions → high ↗ Some management actions have been successful, and species are being monitored to confirm eradication. The distribution of some other taxa has remained stable / been kept under control. However, a few taxa have increased in extent. So overall there is no change, and the level of success is partial. Assessment done in 2023 based on data from 2020–2022 were compared to previous assessment to indicate changes and achievements of managing invasions. If successful, the ‘Mouse-free Marion’ Project would be a significant achievement, and, although less pressing, other eradications would lead to an increase in this indicator. 2359 100 Chapter 7: Gaps 2360 Authors: John R. Wilson, Katelyn T. Faulkner, Laura Fernández Winzer, Emily J. McCulloch-Jones, 2361 Brian W. van Wilgen, Tsungai A. Zengeya 2362 Key gaps1 2363 • The indicators developed for this report need to be tested and aligned to other government 2364 reporting processes. 2365 • There is insufficient information on how invasive species move and are moved around South 2366 Africa. A system to track within-country dispersal is required if South Africa is to effectively 2367 manage the spread of invasive species. 2368 • Data on the presence, distribution and abundance of alien species need to be collected, collated, 2369 and integrated into national and global databases to facilitate the planning of interventions. 2370 • The systematic quantification of the impacts of biological invasions is needed to facilitate the 2371 prioritisation of interventions, provide a defensible rationale to underpin government investment, 2372 and provide background to efforts to communicate the severity of the issue. 2373 • A comprehensive policy, and a strategy to implement such a policy, are needed to guide 2374 interventions on biological invasions in South Africa. 2375 • The efficacy of most interventions is not monitored in terms of outputs and outcomes. Formal 2376 programs that monitor progress towards reducing the negative impacts of invasions would allow 2377 for control measures to be compared and improved. 2378 • Several gaps specific to the Prince Edward Islands were identified (e.g., in terms of identifying 2379 incursions, and the need for closer co-operation between management and research), these are 2380 discussed in Chapter 6. 2381 • Stakeholder engagement is needed to evaluate how the report is currently used, and what can be 2382 done to improve uptake and better address stakeholder needs. 2383 7.1 Process for identifying gaps 2384 We identified gaps from two sources. 1) Gaps identified in the previous reports were evaluated, and 2385 progress (or lack thereof) to address these are highlighted (Tables S6.1, S6.2). Text from the chapter 2386 on gaps from the second report is included below and updates noted. 2) Gaps identified by external 2387 reviewers and the Reference and Advisory Committee (RAC) were evaluated. These are listed in 2388 section 7.8 below. 2389 1All but the last two key gaps are the same as the 2nd report as, while there has been progress on some of these, none are fully addressed yet (see Tables S7.1, 7.2) 101 We recognise that the next comprehensive report will need to fully examine these gaps and should 2390 systematically evaluate gaps in reporting and information. Several other sources of gaps or methods 2391 to identify gaps were flagged and will form a core part of future reports. Gaps were identified during 2392 the IPBES IAS Global Assessment, specifically table SPM.A1 in one of the final drafts of the assessment 2393 addressed gaps. However, as the details will only become publicly available in October 2023, these 2394 gaps could not be assessed during this report cycle. It is also planned to have broader stakeholder 2395 consultation as part of the initiation of the next comprehensive report to determine how this report 2396 is and can be used (cf. a recent end-user survey was conducted as part of South Africa’s National 2397 Biodiversity Assessment to identify topics that should be the focus of future assessments). Finally, the 2398 report will need to look at indicators that are adopted as part of the Kunming-Montreal Global 2399 Biodiversity Framework (GBF) (see Box 1.2). 2400 7.2 Indicators—improving how invasions are measured and providing a link to other reports 2401 The indicator framework as a whole was tested using the Prince Edward Islands (Chapter 6). This work 2402 has highlighted some issues with the indicators (currently addressed through edits to the metadata of 2403 the species lists). Additional indicators, that link to the GBF, are under-development, and a recent 2404 study has identified essential properties for such indicators (Vicente et al. 2022). As the reports 2405 continue, and in light of international developments, the indicator framework will be adjusted, in 2406 particular with revised factsheets produced as part of the next report. 2407 7.3 Pathways—tracking invasions across South Africa 2408 There is still a need to develop a framework to categorise pathways within a country as there are 2409 substantive quantitative and qualitative differences between introductions to and within the country. 2410 In the absence of such a framework, information on how species are dispersing with the country, and 2411 processes to reduce such dispersal, invasive species, once established in the country, will continue to 2412 spread rapidly and impacts will increase. Some progress has been made to adjust the pathway 2413 classification scheme for South Africa (cf. Faulkner et al. 2020), and this will be implemented in future. 2414 7.4 Species & Sites—mapping invasions in space and over time 2415 The southern African Plant Invaders Atlas (SAPIA) was last updated in March 2020, and there has been 2416 no data collection or collation since. This cessation in SAPIA represents a major threat to South Africa’s 2417 ability to track spatial patterns in plant invasions over time, noting that such systematic and verified 2418 monitoring of data can only be partially addressed through ad hoc citizen science records. As noted in 2419 the second report, there are significant gaps in our knowledge of the presence and distribution of taxa 2420 not currently covered by specific atlasing projects. Remote sensing still promises much as an approach 2421 102 to improving distribution data, but has not, yet, delivered tangible results that can be used in this 2422 report. There continue to be very few reliable data sources on the relative abundance (cover, biomass 2423 or population size) of alien species at specific sites. Detailed maps at national scale and local scale 2424 estimates of the impact of invasions are needed to appropriately prioritise interventions across sites 2425 and so that interventions can be adjusted to respond to invasions before such invasions are 2426 widespread and damaging. 2427 7.5 Species & Sites—determining the impacts and costs 2428 For the government to continue to invest substantial resources in managing biological invasions the 2429 benefits that interventions bring in alleviating the negative impacts caused to all sectors of South 2430 African society and to the country’s unique biodiversity must be clearly documented. Data on impacts 2431 are essential if control measures are to be prioritised and to track the effectiveness of interventions 2432 (e.g., in terms of increasing the resilience of South African cities, towns, and rural communities to 2433 droughts and fires; ensuring agricultural sustainability; and protecting our natural capital for future 2434 generations). While the development of a workflow and the collation of economic estimates 2435 represents a significant advance, a systematic method for assessing the impacts of biological invasions 2436 at a site is still needed (i.e., the combined impacts of all alien species present). Such assessments will 2437 require directed research to estimate the impacts of biological invasions in economic and social terms. 2438 Consideration should also be given to the value of long-term monitoring to track impacts and how 2439 they change in response to different interventions. 2440 7.6 Interventions—the need for an over-arching policy and strategy 2441 South Africa still does not have a comprehensive overarching national government policy on biological 2442 invasions. A national strategy on biological invasions has been drafted, but, as of May 2023, has not 2443 gone for public comment. This ‘policy vacuum’ has been flagged as an important factor limiting the 2444 effectiveness of past efforts to control biological invasions (Lukey and Hall, 2020). A comprehensive, 2445 evidence-based policy on biological invasions would clarify the government’s position, guide decision-2446 makers when implementing legislation, and assist the legislature when making and amending relevant 2447 laws. Crucially such a strategy or policy will need to be cognisant of recent international agreements 2448 (e.g., the GBF) and best international practice (e.g., the IPBES Thematic Assessment of Invasive Alien 2449 Species and their Control due to be released October 2023). Within this context, the timing for an 2450 over-arching national strategy for South Africa is particularly propitious. The development of a 2451 comprehensive science-informed strategy promises to provide impetus to address all the gaps 2452 identified in this report and ensure we have a South Africa protected from the harm caused by 2453 biological invasions for the benefit of the environment and human livelihoods. 2454 103 7.7 Interventions—measuring the effectiveness of interventions 2455 There continues to be no long-term plans for monitoring interventions in terms of how they reduce 2456 biological invasions and their negative impacts, and it is unclear how the collection and reporting of 2457 accurate monitoring data is incentivised or penalised if it is not forthcoming. Very few research 2458 projects have assessed the impact of particular policies—a systemic focus on monitoring and 2459 evaluation across the board would help both to demonstrate the impact of interventions and to 2460 increase the efficacy of the interventions themselves. Good data on monitoring costs money, but is a 2461 prerequisite for effective adaptive management and ensuring new technologies are used 2462 appropriately. Such monitoring provides significant returns on investment. 2463 7.8 Suggestions for extensions to the scope of the report 2464 Various requests have been made to include additional information in future reports. 2465 • The contribution of work on biological invasions to human capacity development in the 2466 biodiversity sector including through postgraduate research, other skills development (e.g., 2467 training courses), and secondary and tertiary courses. 2468 • The social benefits created through investments in work on and control of biological invasions, 2469 including number of jobs created and value-added products. 2470 • The potential impact of invasions and the costs of ineffective (or a lack of) interventions, i.e., 2471 both a projection of likely future impacts and an evaluation of the counter-factual if different 2472 interventions had been implemented. 2473 • Improved presentation of impacts and management in economic terms. 2474 • The resources available to practitioners, managers and land-owners (e.g. relevant books, 2475 identification charts, apps, websites etc.); including the development and uptake of effective 2476 tools or guidelines for management (e.g., of herbicides). 2477 • An evaluation of public awareness and perceptions of biological invasions, their management, 2478 and how these change over time. 2479 • An assessment of communities of practice and the degree to which there is integrated 2480 governance. 2481 In a few cases the existing indicators are appropriate to capture these issues, although the issues have 2482 either not been evaluated to date or there is a lack of data. In many other cases, these issues cannot 2483 be captured by the current set of indicators. However, a major conclusion of this, and previous reports, 2484 is that how interventions reduce or ameliorate the damage caused by invasions (i.e., outcomes) is 2485 rarely monitored. As a consequence, the impacts of biological invasions have not been alleviated as 2486 104 much as they could have been or if interventions are effective it has is not possible to demonstrate 2487 this. The report needs to provide a balance between ensuring there is a focus on biological invasions 2488 (as per the remit) and looking at invasions in the broader context (without replicating other reporting 2489 processes). Moreover, extending the report scope will both extend the resources required (e.g., total 2490 cost to produce the report) and the expertise needed to achieve this (e.g., economists and social 2491 scientists). 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