The Status of Biological Invasions and their Management in South Africa in 2019

2019 Biological invasions are a major threat to South Africa’s biodiversity, economy, and sustainable development. This report is a part of South Africa’s commitment to alleviating these impacts. It is a comprehensive national-scale assessment with contributions from 36 experts from 16 institutions. Drafts of the report were available for comment in two substantive rounds of review, with over 350 comments received from 17 institutions. This report is unique in the world in focussing specifically on invasions and is an important part of South Africa’s global leading position on the issue (the government invests over 1 billion ZAR per year to deal with the problem). The report is based around a suite of 20 indicators that provide details on: 1) how alien species are introduced and move around the country; 2) the status and impacts of 1880 alien species of which 776 are invasive; 3) the degree to which sites are invaded and impacted; and 4) the effectiveness of the full range of interventions that South Africa has used to address the problem. This report provides valuable insights into how South Africa can reduce the negative impacts of biological invasions on ecosystems, the economy, and people while retaining the benefits alien species provide where this is possible and desirable. It collates foundational information essential for researchers of the topic and provides an assessment of interventions that is vital for policy makers and managers. Copyright © 2020 South African National Biodiversity Institute (SANBI). All rights reserved. Reproduction of this publication for educational or other non-commercial purposes is authorised without prior written permission from the copyright holder provided the source is fully acknowledged. Reproduction of this publication for resale or other commercial purposes is prohibited without prior written permission of the copyright holder. ISBN: 978-1-928224-41-9 THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2019 THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA II Lead editors: Tsungai A. Zengeya1, 2, John R. Wilson1, 3 Chapter lead authors: Katelyn T. Faulkner1, 2, Tendamudzimu Munyai1, Marthán Theart1, Brian W. van Wilgen3, John R. Wilson1, 3 & Tsungai A. Zengeya1, 2 With contributions from: Ruqaya Adams1, Johan Baard4, Michael Braack5, Oupa Chauke5 , Nicholas Cole4, Charles L. Griffiths6, Lesley Henderson7, Charlene Janion-Scheepers8, 9, Martin P. Hill10, Anja le Grange1, Philip Ivey10, Stiaan Kotze5, Dunisani Malukele11, Clova A. Mabin12, Nonkazimulo Mdidimba13, Siyasanga Miza1, Musa Mlambo13, Ernest Mpofu14, Xoliswa Ndeleni1, Bernard Ndou5, Khathutshelo Nelukalo5, Livhuwani Nnzeru5, Andrew A. Turner15, Trudy Paap16, Tamara Robinson3, Nicola J. van Wilgen3, 5, Karabo Wanjau5, Andrew Wannenburgh5, Pieter Winter1, Costas Zachariades7. 1South African National Biodiversity Institute 2DSI-NRF Centre of Excellence for Invasion Biology, Department of Zoology and Entomology, University of Pretoria 3DSI-NRF Centre of Excellence for Invasion Biology, Department of Botany and Zoology, Stellenbosch University 4South African National Parks 5Department of Forestry, Fisheries, and the Environment 6DSI-NRF Centre of Excellence for Invasion Biology, Department of Biological Sciences, University of Cape Town 7Plant Health and Protection, Agricultural Research Council 8Iziko South African Museum 9Department of Zoology and Entomology, University of the Free State 10Centre for Biological Control, Department of Zoology and Entomology, Rhodes University 11Department of Water and Sanitation 12South African Institute for Aquatic Biodiversity 13Albany Museum 14Department of Agriculture, Land Reform and Rural Development 15CapeNature 16Forestry and Agricultural Biotechnology Institute, Department of Biochemistry, Genetics and Microbiology University of Pretoria Cover photographs: Top left – boxing glove cactus (Cylindropuntia fulgida var. mamillata) - T. Xivuri Top middle – diver team surveying harbours for marine alien species in Saldanha Bay - T. Robinson Top right – European shore crab (Carcinus maenas) - S. Miza Bottom left – vermiculated sailfin catfish (Pterygoplichthys disjunctivus) - R. Karsing Bottom middle – Common myna (Acridotheres tristis) - R. Taylor Bottom right – pine trees (Pinus species) - B. van Wilgen Citing this publication: For citations in the scientific literature: Zengeya, T.A. & Wilson, J.R. (eds.) 2020. The status of biological invasions and their management in South Africa in 2019. pp.71. South African National Biodiversity Institute, Kirstenbosch and DSI-NRF Centre of Excellence for Invasion Biology, Stellenbosch. http://dx.doi.org/10.5281/zenodo.3947613 For citations in policy documents: SANBI and CIB 2020. The status of biological invasions and their management in South Africa in 2019. pp.71. South African National Biodiversity Institute, Kirstenbosch and DSI-NRF Centre of Excellence for Invasion Biology, Stellenbosch. http://dx.doi.org/10.5281/zenodo.3947613 ISBN: 978-1-928224-41-9 Technical editing: Nicole L. Meyer Design & layout: Harry's Printers Tshwane Cover design: Harry's Printers Tshwane Printed by: Harry's Printers Tshwane, 69 Pretorius Street, Pretoria 0001 South Africa. Email: [email protected] III INDEPENDENCE OF THE STATUS REPORT This status report constitutes an independent assessment of the status of biological invasions and their management in South Africa. The report is intended to inform the development and ongoing adaptation of appropriate policies and control measures, both to reduce the negative impacts of alien species on ecosystems, the economy, and people, and to retain any benefits of invasive species where possible and desirable. The compilation of the report was overseen by employees of the South African National Biodiversity Institute (SANBI) and the DSI-NRF Centre of Excellence for Invasion Biology (CIB). Inputs (including data, peer-reviewed papers, and unpublished reports) were also obtained from researchers and managers from diverse institutions across South Africa. Funding for the compilation of the report was obtained through the National Department of Forestry, Fisheries, and the Environment (DFFtE) as part of SANBI’s Medium Term Expenditure Framework. In order to address any potential conflicts of interest, and to ensure independence of the report, the following steps were taken: • Drafts of the status report were widely circulated to contributing authors and other stakeholders, who were invited to submit comments, concerns or additional information, with two dedicated rounds of review in 2019 and 2020; • A close to final version of the report was also reviewed in depth by two South African and one international expert on biological invasions; • Comments and concerns raised were captured in a database, along with the drafting team’s responses to these comments and concerns. This database is available on request; and • A Reference and Advisory Committee (RAC) oversaw the process taken to compile and review the report, as well as the drafting team’s response to the comments and concerns raised by stakeholders, with a view to strengthening the process if necessary for future reports. The RAC was chaired by an expert on assessments from the University of the Witwatersrand, South Africa. pines invading fynbos - B. van Wilgen IV INDEPENDENCE OF THE STATUS REPORT ............................................................................................... III PREFACE ...................................................................................................................................................................... VII LIST OF ACRONYMS ............................................................................................................................................. IX GLOSSARY .................................................................................................................................................................. X SUMMARY .................................................................................................................................................................. XV CHAPTER 1: INTRODUCTION 1 1.1. The importance of biological invasions to South Africa .................................................................. 1 1.2. The mandate, purpose, and structure of the status report ............................................................. 1 1.3. Process for the compilation of the status report ................................................................................. 3 1.4. Indicators used, updating the species list, and tracking change ................................................. 6 1.5. Aspects of biological invasions that are not covered ....................................................................... 8 Box 1.1. Is this the 2019, 2020, or 2021 Report? .......................................................................................... 8 CHAPTER 2: PATHWAYS 9 2.1. Introduction pathway prominence ........................................................................................................... 10 2.2. Introduction rates ............................................................................................................................................. 11 2.3. Within-country pathway prominence ..................................................................................................... 14 2.4. Within-country dispersal rates .................................................................................................................... 14 Box 2.1. Movement of alien species within Africa ...................................................................................... 15 2.5. Trends in pathway indicators ....................................................................................................................... 16 CHAPTER 3: SPECIES 19 3.1. Number and status of alien species .......................................................................................................... 20 3.2. Extent of alien species ..................................................................................................................................... 21 3.3. Abundance of alien species ......................................................................................................................... 23 3.4. Impact of alien species ................................................................................................................................... 23 Box 3.1. The polyphagous shot hole borer and Fusarium dieback in South Africa ...... 24 3.5. Trends in species indicators .......................................................................................................................... 25 TABLE OF CONTENTS V CHAPTER 4: SITES 27 4.1. Alien species richness ..................................................................................................................................... 28 4.2. Relative invasive abundance ........................................................................................................................ 32 4.3. Impact of invasions .......................................................................................................................................... 33 Box 4.1. Urban invasions ......................................................................................................................................... 35 4.4. Trends in site indicators .................................................................................................................................. 36 CHAPTER 5: INTERVENTIONS 37 5.1. Input-quality of the regulation framework ............................................................................................ 39 5.2. Input-money spent .......................................................................................................................................... 43 5.3. Input-planning coverage ............................................................................................................................... 43 5.4. Output-pathways treated .............................................................................................................................. 44 5.5. Output-species treated ................................................................................................................................... 44 5.6. Output-sites treated ......................................................................................................................................... 46 5.7. Outcome-effectiveness of pathway treatments ................................................................................. 50 5.8. Outcome-effectiveness of species treatments .................................................................................... 50 5.9. Outcome-effectiveness of site treatments ............................................................................................ 51 Box 5.1. The proposed listing of rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta) as invasive species in terms of NEM:BA ............................................................................. 51 Box 5.2. The first criminal conviction for a contravention of the alien and invasive species provisions of NEM:BA ............................................................................................................................................... 52 Box 5.3. The control of triffid weed (Chromolaena odorata) in the Hluhluwe-iMfolozi Park in KwaZulu-Natal: an example of changing fortunes ..................................................................................... 53 5.10. Trends in interventions indicators ........................................................................................................... 54 CHAPTER 6: GAPS 59 6.1. Process for identifying gaps ......................................................................................................................... 60 6.2. Indicators-improving how invasions are measured and providing a link to other reports ............................................................................................................................................................................ 60 6.3. Pathways-tracking invasions across South Africa ............................................................................... 60 6.4. Species & Sites-mapping invasions in space and over time .......................................................... 61 6.5. Species & Sites-determining the impacts and costs ......................................................................... 61 6.6. Interventions-the need for an over-arching policy and strategy ................................................ 62 6.7. Interventions-measuring the effectiveness of interventions ........................................................ 62 VI ACKNOWLEDGEMENTS ....................................................................................................................................... 63 REFERENCES .............................................................................................................................................................. 65 LINKS TO APPENDICES AND SUPPLEMENTARY MATERIAL ........................................................... 71 VII PREFACE The value of biosecurity to South Africa and the threat of biological invasions have never been clearer. Biological invasions are an ongoing threat to South Africa’s biodiversity and ecosystem integrity, and to society through impacts on people’s livelihoods and their health (including SARS-CoV-2 the invasive organism behind the Covid-19 pandemic). The polyphagous shot hole borer is sweeping across our country killing the trees in our gardens and on our streets, and imperiling agriculture. Invasive plants have exacerbated the droughts in Cape Town, the wildfires in Knysna, and the floods in KwaZulu-Natal. Invasive plants reduce the capacity of our natural rangelands to support livestock production, thereby threatening rural livelihoods and food production. The South African government has implemented legislation to deal with biological invasions, investing over 1 billion ZAR per year to protect our natural assets from their impacts. To assist with these efforts, the South African National Biodiversity Institute (SANBI) has been mandated to report on the status of biological invasions and the effectiveness of their management in South Africa. This second report represents an important step towards the production of a dashboard where policy makers and managers can evaluate the status of biological invasions as they are playing out, and adapt their management accordingly. Although some successes in the management of biological invasions have been achieved, current efforts would be greatly improved by the adoption of a national policy and strategy for managing biological invasions, project-level planning for prevention and management, formal programmes to monitor the effectiveness of interventions, and enhanced spatially explicit data. This report rightly highlights these needs. This is an important, but deeply worrying, time to be working on biological invasions. SANBI occupies a unique position at the interface of science and policy, where it is able to generate and harness knowledge on biological invasions to provide evidence for decision-making. SANBI Acting Chief Executive Officer: Ms Carmel Mbizvo XIV • Regulation: 1) a law or rule made by the Executive Authority in terms of original legislation to regulate conduct (in this case the NEM:BA A&IS Regulations); 2) the act of regulating, i.e. to govern or direct according to rule, or to make regulations (authoritative rules) for certain conduct. • Regulatory lists/listing: a list of alien species that are regulated under the NEM:BA A&IS Regulations. For a definition of the regulatory categories see Table 5.2 and Supplementary Material section S5.2. • Release (cf. escape): the intentional introduction of an alien species to a site outside of captivity or cultivation. This refers to both legal and illegal introductions, however if a legally introduced alien species is illegally released outside of captivity or cultivation then it is classified as an escape. • Returns on investment: the amount of value that is gained as a result of a particular amount spent on an intervention. This can be calculated as a benefit: cost ratio whereby each rand spent (the cost) is set against the amount of rands gained (benefit). An intervention is technically cost-effective if the benefit: cost ratio is greater than one, although more generally cost effectiveness is about maximising the ratio. • Risk: the likelihood and consequence of an event, in this context the event is a biological invasion. • Risk analysis: the process of identifying and assessing the likelihood and consequence of an event, as well as considerations as to how to manage and communicate the risk (see Figure S5.1). • Risk assessment: a component of risk analysis that focuses on evaluating the likelihood and consequence of an event taking place. In this context, an event is the likelihood of an alien species becoming an invasive species and the negative impacts that would result. • Site: a defined spatial area, for example a protected area (as defined by the National Environmental Management: Protected Areas Act, 2003), or an administrative unit (with national and provincial administrative boundaries as defined by the Constitution of the Republic of South Africa, 1996). • Spread: see Dispersal • Strategy: a high-level plan for achieving management goals in a specific time frame under conditions of uncertainty. • Stowaway: the accidental introduction of an alien species attached to or within a transport vector or their associated equipment and media. The organism is transported by chance, and there is no specific, natural association with the vector. • Taxon (plural taxa): a group of organisms that all share particular properties (usually evolutionary history). The grouping can be below, at or above the species level. • Threat: the negative impacts that may occur if an event happens (cf. risk where the likelihood is explicit). In this context this refers to the negative impacts resulting from a component of the invasion debt being realised. • Unaided dispersal: see Natural dispersal. • Unregulated introduction: an introduction that was not approved by the relevant South African authorities under the relevant regulations prior to the date at which it arrived in the country. • Water Management Area: an area established as a management unit in the National Water Resource Strategy within which a catchment management agency conducts the protection, use, development, conservation, management, and control of water resources. XV Biological invasions are a leading cause of global change and a major threat to South Africa’s environment and socio-economic development. South Africa’s response to this issue has been widespread and substantial. The government has spent in excess of 1 billion ZAR per year since 2013 on biosecurity and control projects and has listed 556 invasive taxa as requiring control. This report¹ assesses the status of biological invasions in the country and the effectiveness of South Africa’s response. It has been estimated that three new alien taxa arrive in South Africa accidentally or illegally every year. While this rate appears to have declined, such introductions continue to add to the number of invasive species in the country. Notable recent introductions include the tomato leaf miner (Tuta absoluta), which was detected in 2016 and is now a major agricultural pest, and the polyphagous shot hole borer (PSHB, Euwallacea fornicatus), an ambrosia beetle from Southeast Asia which was first detected in 2017 in Pietermaritzburg. The PSHB and its associated fungus have already killed thousands of trees in South Africa’s streets, gardens, protected areas, and orchards, and threaten millions more. South Africa’s ability to know where, when, and how interventions should be implemented to prevent new introductions has been improved by recent research that has clarified how the pet trade, the medicinal plant trade, contaminants of animal imports, and shipping function as introduction pathways. Effective protocols are increasingly being implemented to regulate intentional legal introductions of alien species and to ensure that the risks of such imports are minimised. However, there is insufficient capacity to prevent accidental or intentional illegal introductions of alien species. More work is needed to elucidate the role of many pathways in facilitating introductions and invasions. Increasing volumes of trade and travel, particularly within Africa, represent enormous opportunities for South Africa’s economic development, but unless judicious biosecurity measures can be implemented, South Africa will continue to import (and export) invasive species. Similarly, the development of systems to track and understand how invasive species move and are moved around the country are needed for the spread to be effectively managed. This report provides information on 1880 alien species known to occur in South Africa. At least a third of these species have escaped (or were deliberately released) from captivity or cultivation and have become invasive. The impacts of 215 invasive species have been formally assessed, and seven of these were found to cause major or massive negative environmental impacts, while one species was found to have major negative socio-economic impacts. Impact assessments are needed on the remaining species, but in many cases there is a lack of reliable data. Invasive trees use up 3–5% of South Africa’s surface water runoff each year, exacerbating the effects of droughts. If there were no invasive trees in the City of Cape Town’s catchment, ‘Day Zero’ ² would have been delayed by 60 days during the peak of the water crisis in 2017. The destructive wildfires in Knysna in 2018 were exacerbated by plant invasions (15% more fuel was burnt in invaded areas than uninvaded areas, increasing the severity of fires and making containment measures ineffective). Invasive plants reduce the value of livestock production from natural rangelands by ZAR 340 million per year, and this will grow rapidly if invasions are not controlled. Biological invasions are the thirdlargest threat to South Africa`s biodiversity (after cultivation and land degradation), and are responsible for 25% of all biodiversity loss. SUMMARY 1 This second report focuses on the status as of December 2019 and the trends since the first report (i.e. since December 2016) as mandated under the NEM:BA A&IS Regulations. The report is composed of chapters addressing the pathways of introduction and spread, the status of alien species and their impacts, the degree to which sites are invaded, and the effectiveness of interventions; and discusses trends in four head-line indicators (Table A.1) and 20 lower-level indicators (discussed at the end of each chapter). The report concludes with a chapter identifying key gaps that, if addressed, would improve the ability of South Africa to respond to the challenges posed by biological invasions and improve the returns on investment. 2 ’Day Zero’ was the day during Cape Town’s water crisis of 2015–2018 that the City’s dams would have run out of potable water. XVI Several initiatives have been highly effective in controlling invasions, and dramatic positive returns on investment have been reported for the utilisation of biological control to reduce problems with invasive plants (benefit:cost ratios from 8:1 to ~4000:1). However, the efficacy of most interventions is not routinely monitored. Improved data on the outputs of interventions, and a focus on outcome-orientated targets, would allow managers to adapt their plans, and policy-makers to revise regulations and strategies accordingly. There are encouraging signs that the NEM:BA A&IS Regulations promulgated in 2014 are beginning to become effective—the first successful prosecution was in 2019, and the process for granting permits is now well-established and functional (~40 per month). However, proposals to revise the regulatory lists in early 2018 were substantially delayed due to contested species, in particular trout. This has adversely affected the ability to revise the current regulatory lists (proposed changes listed in early 2018 came into effect in March 2021, and risk analyses on 25 listed alien species recommend that the listing of 12 of them should be changed). Biological invasions continue to be a significant, pressing, and in many cases increasing threat to South Africa. These challenges can and are being addressed—government and public initiatives have, in some cases, reduced the impacts and threats posed and provided valuable returns on investment in terms of rural development and job creation. However, the effectiveness of current interventions could be vastly improved with the introduction of goal-oriented management plans, by monitoring outcomes in terms of those goals rather than inputs, by applying a flexible approach based on the principles of adaptive management, focussing on priority sites and species, and by improving implementation of best-practice control methods in the field. European shore crab (Carcinus maenas) - S. Miza Common starling (Sturnus vulgaris) - C. Griffiths XVII Table A.1. The status of biological invasions in South Africa at the end of 2019 as per the four headline indicators. Head-line indicator Trend (confidence) Desired trend Current status Outlook A. Rate of unregulated introduction of new species (Low) Between 2010 and 2019 approximately 3 new taxa were introduced per year either accidentally or intentionally but illegally. This was lower than the estimated rate during the previous decade (~ 5 per year). Despite the apparent recent decline in introductions, opportunities for the introduction of alien species are expected to increase as the volume of trade and travel increases. Whether this results in the introduction of more invasive species will depend on the degree to which key pathways are identified and prioritised for management. Improvements to inspection, management, and the incursion response at border would strengthen South Africa’s biosecurity. B. Number of invasive species that have major impacts Not assessed In the first report, 107 alien species were identified by experts as particularly damaging. A process is under way to formally assess all invasive species using the IUCN’s EICAT scheme. So far 215 species have been assessed, and eight found to cause major to massive impacts (five fish, two grasses, and one mammal species). However in many cases there was a lack of reliable data. The number of alien species recorded to have major or massive negative impacts will increase as more species are formally assessed. The formal assessment of the impact of alien species provides the rationale for regulation and management, can improve compliance and implementation of intervention measures, and assist to resolve conflicts. However, impact assessments are hampered by a lack of reliable data for most species. If this situation persists, regulations will continue to be vulnerable to legal challenges. It is very difficult to control invasive species with major impacts in a way that will reduce such impacts to moderate or minor, but this has arguably been achieved by biological control for over 30 invasive taxa. On-going investment in biological control will likely result in more such successes. If alien species that currently have moderate or minor impacts are prevented from increasing in abundance and extent to the point where they have major impacts or, where feasible, such species are eradicated from South Africa, then a significant return on investment will also be made. no change; increase; decrease XVIII Head-line indicator Trend (confidence) Desired trend Current status Outlook C. Extent of area that suffers major impacts from invasions Not assessed Biological invasions continue to cause major impacts on both rural and urban communities by, amongst other things, reducing South Africa’s water resources, degrading pastureland, and making fires more intense and more difficult to control. Biological invasions continue to contribute to biodiversity loss and ecosystem change. 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. D. Level of success in managing invasions (Low) Recent studies support the conclusions of the first report that: 1) biological control can be highly effective; and 2) improvements both in monitoring and control efficiency will be needed if invasions are to be effectively controlled. In several water bodies, alien fish species have been extirpated in a manner that allows for the recovery of native species. This is a major new success. An assessment of the effectiveness of control measures remains challenging in the absence of any formal programmes that monitor outcomes. Should this situation continue, then whether the goals of control – to reduce the number, abundance, extent, and impact of invasions – are being achieved will remain unknown, management cannot be adaptive, and levels of success will remain low. If these issues are not urgently addressed, the impacts and costs of invasions will rise significantly. Table A.1 The status of biological invasions in South Africa at the end of 2019 as per the four headline indicators. (Contd) no change; increase; decrease XIX swift woodlouse (Porcellio laevis) - C. Griffiths XX Pacific oyster (Magallana gigas) - S. Miza 1 1 INTRODUCTION Authors: 1.1. The importance of biological invasions to South Africa Biological invasions have had varied and significant impacts on all sectors of South African society. They are a major threat to socioeconomic sustainability, they have exacerbated droughts, floods and wild-fires, and have caused significant losses in agriculture, pastoralism, and forestry. Biological invasions account for a quarter of all biodiversity loss in South Africa to date (van Wilgen et al. 2008). The South African government spends well over 1 billion ZAR per year on their management (Figure 5.1, see pg. 42). Given South Africa’s rich and varied cultural and biological diversity, and the long history both of alien species introductions and of attempts to regulate, manage, and study them, South Africa is a global exemplar of the impacts of and potential responses to biological invasions (van Wilgen et al. 2020b). South Africa has taken a world-leading stance in controlling invasions specifically in terms of combining efforts at alien plant clearing with poverty alleviation, the use of classical biological control, and its innovative Alien and Invasive Species (A&IS) Regulations of 2014. One feature of the A&IS Regulations is the requirement for the South African National Biodiversity Institute (SANBI) to report, every three years, on the status of biological invasions and their management in South Africa. 1.2. The mandate, purpose, and structure of the status report The mandate for the status report arises from section 11 of the A&IS Regulations of 2014 that were promulgated under the National Environmental Biodiversity Act (NEM:BA) (Act 10 of 2004): (1) The Institute [i.e. the South African National Biodiversity Institute (SANBI)] or a body designated by the Institute must, for the purpose of reporting as contemplated in section 11(1) (a) (iii) of the Act, submit a report on the status of listed invasive species to the Minister within three years of the date on which these regulations come into effect, and at least every three years thereafter [the regulations came into effect on 1 October 2014]. John R. Wilson Tsungai A. Zengeya wattles and pines invading fynbos - B. van Wilgen 2 (2) A report contemplated in sub-regulation (1) must contain a summary and assessment with: (a) the status of listed invasive species and other species that have been subjected to a risk assessment; and (b) the effectiveness of these regulations and control measures based inter alia on information from: (i) notifications received from owners of land regarding listed invasive species occurring on their land; (ii) permits issued for listed invasive species; (iii) Invasive Species Monitoring, Control and Eradication Plans¹ received from organs of state and management authorities of protected areas; and (iv) emergency interventions and enforcement actions involving listed invasive species issued by the Minister. (3) In preparing a report contemplated in sub-regulation (1), the Institute must carry out the research and monitoring necessary to identify the matters contemplated in sub-regulation (2). More broadly, however, the status report aims to strengthen the links between basic research, policy, and management by detailing the current status and providing support to decision makers that is policy relevant but not policy prescriptive (see Figure 1.1 in the first report). The first report – produced in 2017 and released in 2018 – was structured around an indicator framework that explicitly considers biological invasions in terms of pathways, species, sites, and interventions (separated into inputs, outputs and outcomes, see Figure 1.3). This indicator framework provides a transparent and objective method for the establishment of a baseline against which to assess trends, set realistic management targets, and for highlighting important gaps in the evidence needed to support decision-making. This second report is similarly structured around this indicator framework with the intention of refining and updating values in the first report. The second report focuses on the status as of the end of 2019, noting trends over the past three years for the four headline indicators (Table A.1) and for 20 indicators tracking pathways, species, sites, and interventions (sections 2.5, 3.5, 4.4, and 5.10). Data are more systematically curated with sources clearly indicated. Trends can be more easily tracked, but some baselines had to be revised. See Appendix 1 for details on sources of data, descriptions, levels of confidence, and indicators that were informed by such data. The longer-term plan is to develop an on-line resource with indicator values updated as soon as new information becomes available (i.e. a dashboard), a short status report summarising trends every three years as per the current regulatory requirement, and a comprehensive report every decade or so (see Supplementary Material section S1.2). Each chapter starts with a summary of the state of the indicators, and then discusses key changes in the indicators. Much of the detail underlying the production of this second report is contained within the appendices and supplementary material available on-line (links to them are on the last page of this report). 1 The ‘Invasive Species Monitoring, Control and Eradication Plans’ referred to in the regulations are intended to be drawn up for specific sites. For the purposes of this second report these are referred to as site management plans. This is distinct from species management programmes which focus on controlling particular species often across the whole of South Africa. 3 1.3. Process for the compilation of the status report The process for compiling the second report was broadly similar to that for compiling the first report. A status report drafting team was appointed, and a Reference and Advisory Committee (RAC) established to oversee the process. The writing team drafted various versions of the second report in consultation both with the RAC and stakeholders (Figure 1.1). Each step is described in detail below. Appoint status report drafting team: The SANBI-CIB drafting team is similar to that of the first report, but there has been a shift in emphasis from a team headed up by the CIB, to a team led by SANBI with the CIB providing assistance and advice. A notable change was the inclusion of a legal specialist (based at SANBI) on the drafting team. Appoint the RAC: the RAC was established to provide oversight of the process and review documents produced. The first meeting of the RAC was on 31 May 2019. At the request of the RAC, a zero-order draft was produced and sent to the RAC on 1 July 2019, and subsequently approved. The RAC similarly reviewed a version of the first order draft before it went out for public comment, and reviewed the second order draft before the final report was produced. The Chair of the RAC also reviewed how the comments received during the stakeholder and expert review processes were addressed, i.e. acted in a review editor role. Finally, the RAC intends to provide advice both in terms of the public release of the second report, and on reflecting on the process. smallmouth bass (Micropterus dolomieu) - D. Impson pompom weed (Campuloclinium macrocephalum) - L. Henderson 10 Indicators covered in this chapter: 2. Introduction rates 3. Within-country pathway prominence 1. Introduction pathway prominence 4. Within-country dispersal rates PATHWAYS HIGH LEVEL A Rate of unregulated introduction of new species 2.1. Introduction pathway prominence Introduction pathway prominence considers the size of the pathways of introduction in terms of their socio-economic importance [in contrast, introduction rates (indicator 2) looks at whether alien organisms are being introduced along these pathways]. The pathway categorisation scheme used for all pathway indicators is that adopted by the Convention on Biological Diversity (CBD 2014), with proposed revisions by Harrower et al. (2018) [see Harrower et al. (2018) for details on how introductions are classified into the different pathways]. In most cases, introduction pathway prominence has not changed since the first report (39 of the 44 pathways; see Figure 2.1), but the number of fishing boats in South African waters has decreased by 40% and, therefore, so too has the prominence of the pathway related to stowaways on fishing equipment. There has, however, been some significant research on pathways of introduction since the first report, facilitating more robust assessments for some pathways, and for others allowing introduction pathway prominence to be estimated for the first time. Recent research has shown that hundreds of invertebrate taxa are sold in the pet trade (195 tarantula species and 53 other invertebrates, but it is likely that many more are sold), although the role of the pet trade in new introductions versus within-country dispersal is unclear (see Nelufule 2018; Shivambu 2018). Based on these studies the prominence of the pet trade pathway is now scored as moderate (it was scored as minor in the first report). This increase in introduction pathway prominence is due to better knowledge. Whether there has been an actual change in the volume of trade is not known. One introduction pathway that had previously received little research attention is the traditional medicine trade. Hundreds of alien medicinal plant and fungal species (214 species, 101 as propagules) are imported into South Africa, often from multiple sources (Burness 2019; Byrne et al. 2017; Faulkner et al. 2020a). Some of these species (e.g. Moringa oleifera, Nigella sativa and Zingiber officinale) pose an invasion threat to the country as they are imported as viable propagules, have high propagule pressure, and history of invasion elsewhere in the world (Burness 2019). The types of changes made to the data since the first report are shown in Table S2.2 and how these changes have influenced the indicator is shown in Figure S2.20, with details tracked in Appendix 3. 11 2.2. Introduction rates Introduction rates consider the number of new alien taxa introduced through the pathways of introduction, and how this number has changed over time. The introduction pathway of most taxa (54%) introduced to South Africa is still not known. Of the alien taxa known to have been introduced to South Africa, most (15%) are plants that were introduced for horticulture and/or ornamental purposes. Many of the taxa that are known to have been accidentally introduced were introduced through shipping (5% of all introductions). Due to better data, it is clear that new alien taxa continue to be intentionally and accidentally introduced to South Africa, and there has been an increase in the number of taxa that are thought to have been introduced over all time, through 18 of the 44 pathways (Figure 2.1). During the 2017–2019 period new taxa are likely to have been introduced accidentally through the timber trade, shipping (hull fouling or the release of ballast water), as contaminants on imported animals, and through natural dispersal from other African countries where previously introduced. In terms of legal intentional introductions, many alien taxa (157 taxa) have been released as biological control agents against invasive organisms such as invertebrates and plants, with four new taxa introduced to control alien plants during the 2017–2019 period (Table S5.10). Biological control is a highly regulated pathway and, as part of obtaining an import permit, these taxa are assessed and must be found unlikely to have important direct negative impacts. The introduction of biological control agents provides substantial benefits (see Chapter 5 for further details), and to date these introductions have caused no important negative impacts. Therefore, these introductions are not included in the estimate of the high-level indicator ‘Rate of unregulated introduction of new species’. Besides those for biological control, no import permits were issued in the 2017–2019 period for specimens of taxa not previously recorded in the country or for which an import permit had not been previously issued (see Supplementary Material section S5.5 for details). There has been an increase in the number of new alien taxa that are thought to have entered South Africa through natural dispersal from neighbouring countries where they had been previously introduced. Therefore, while many introductions are believed to be due to intercontinental human-mediated dispersal, it appears an increasing number of alien taxa are showing intra-African dispersal (Box 2.1). The types of changes made to the data since the first report are shown in Table S2.3 and how these changes have influenced the indicator is shown in Table S2.4, with details tracked in Appendix 5. 12 Figure 2.1. Current status of the pathways of introduction and changes to the pathways that have been recorded since the first report. No: number of taxa introduced; No since 1st report: change to the number of taxa introduced [ increase; no change; — not applicable (new pathway)]; Change in IR: change in introduction rate relative to last decade [ increase; decrease; minimal change; X no introductions; ? not known]; IPP: introduction pathway prominence [Min: minor; Mod: moderate; Maj: major; PNP: pathway not present; ? not known]; IPP since 1st report: change to introduction pathway prominence since the first report [ increase; decrease; no change; ? not known; — not applicable (first estimate or new pathway)]. 30 MECHANISM OF ENTRY PATHWAY CATEGORY PATHWAY SUBCATEGORY No No Since Change In IR 1st Report IPP Since 1st Report INCREASING HUMAN ROLE 157 93 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?? ? ? ? ? ? ? ? X X X X X X X X X X 17 Release 33 8 3 8 104 15 6 54 16 COMMODITY Escape 38 ur farms 1 302 276 10 2 1 11 15 15 9 Contaminant 35 24 26 37 11 5 0 0 13 3 24 TRANSPORT VECTOR Stowaway 1 0 1 61 76 1 2 NATURAL SPREAD Corridor 0 0 Unaided 13 IPP Mod Min Maj Mod PNP Maj Min Min Mod Maj Maj Min Mod Mod Mod Min Mod Maj Maj Maj Mod Mod Mod Maj Mod Mod Mod Mod Maj Mod Mod Maj Min Min Maj Biological control Stabilisation & Barriers Fishery in the wild Hunting Aesthetic release Conservation in wild Agriculture Aquaculture Botanical gardens/zoos Pet Farmed animals Forestry Fur farms Horticulture Ornamental Research Live food and live baits Other escape Nursery material contaminant Bait contaminant Food contaminant Contaminant of animals Contaminant of plants Seed contaminant Timber trade contaminant Habitat material contaminant Other contaminant Fishing equipment Machinery & equipment People & luggage Packing material Ballast water Hull fouling Land vehicles Other stowaway Canals & artificial waterways Tunnels and bridges Natural dispersal Container & bulk cargo Airplane Ship excluding ballast water or hull fouling Parasites of animals Parasites of plants Other release 13 For nine of the pathways for which estimates were possible there have been minimal changes to the rate at which new alien taxa have been introduced in this decade (2010–2019) in comparison to the previous decade (Figure 2.1). There were fewer introductions for hunting in the current decade in comparison to the previous decade, which could be due to increasing anti-hunting sentiment (Taylor et al. 2015). There appears to have been an increase in the rate at which parasites of imported animals have been introduced. However, there has been a decline, since the previous decade, in live animal imports (Figure S2.8), and so this trend is likely due to recent, directed research interest in parasites of freshwater fish (Weyl et al. 2020) or due to time lags between introduction and detection. Date of introduction is often known for taxa that are intentionally introduced, but for taxa that are accidentally introduced, there is often a significant time delay between when the taxon is introduced and when it is detected. Over the current decade, 57 new alien taxa are known to have been introduced to South Africa, fewer than the 67 taxa recorded for the previous decade (Figure 2.2A). Notable introductions in the last decade include the polyphagous shot hole borer (Euwallacea fornicatus), tomato leaf miner (Tuta absoluta), and fall armyworm (Spodoptera frugiperda). Number of introduced taxa DECADE YEAR Number of introduced taxa All introductions Unregulated introductions 0 0 5 10 15 20 40 60 80 100 1950s 1970s 1990s 2010s 2010 2012 2014 2016 2018 Figure 2.2. Number of recorded introductions to South Africa over time: (A) over the last seven decades and (B) during the last decade. These data are incomplete, particularly for more recent years, as there are time lags between the introduction of a taxon, when it is detected, and the publication of reports of the introduction. A B 14 2.3. Within-country pathway prominence Within-country pathway prominence considers the size of the pathways of dispersal within South Africa, but does not take into account the importance of these pathways for the dispersal of alien organisms. As in the first report, data for within-country pathway prominence were not available for most pathways, and so the indicator could not be populated (see Chapter 6 for details on knowledge gaps and data requirements). However, South Africa has extensive transport networks (e.g. ~750 000 km of roads, https://www.transport. gov.za/web/department-of-transport/roads accessed September 2020) that are used frequently by a large proportion of the country’s population, and that are used to transport a large amount of goods. As an example, in the 2018/2019 financial year there were over 135 000 domestic flight arrivals at South African airports (Airports Company South Africa 2019). The number of domestic flights and the number of passengers travelling on these flights has remained relatively consistent and these numbers are similar to those reported in the first report (see Figures S2.21–S2.23). There are a number of pathways that are facilitating the intentional transport of taxa within the country. For example: the pet trade (Nunes et al. 2017a), the medicinal plant trade (Byrne et al. 2017), and the cultivation of plants for uses related to the green economy (Canavan et al. 2019). It is not clear whether these processes have increased or decreased since the first report. 2.4. Within-country dispersal rates Within-country dispersal rates consider the number of taxa that have dispersed within South Africa through the pathways of dispersal, and how this number has changed over time. Data for within-country dispersal rates have not been collated for the entire country, and so the indicator could not be populated (see Chapter 6 for details on knowledge gaps and data requirements). However, as in the first report, data collected from the literature indicates that alien and native taxa are being intentionally and accidentally transported around the country, and that these taxa are dispersing within the country through many pathways, with taxa dispersing through at least 22 of the 44 pathways of dispersal (Appendix 3). Recent research on biofouling has highlighted the importance of recreational yachts, particularly those used for cruising, in the dispersal of marine alien taxa within South Africa (Peters & Robinson 2017; Peters et al. 2019). Furthermore, 137 alien plant species are considered as transformers in South African National Parks, and most were intentionally introduced as ornamental plants or were dispersed by rivers and animals (Table S2.5), and many utilised multiple pathways (Foxcroft et al. 2019). It is expected that this pattern is applicable for South Africa more broadly. For example, a freshwater gastropod (Tarebia granifera) from South-East Asia, is dispersing rapidly within the country both through natural spread (e.g. on aquatic plants and by attaching to the feathers of birds) and as a stowaway on boats and trailers (Jones et al. 2017). However, it is unclear how the withincountry dispersal pathways have changed since the first report. 15 The introduction of alien species to Africa has increased over time, at least for pests of forestry and agriculture (Graziosi et al. 2020; Sileshi et al. 2019). South Africa is often the entry point for alien species that disperse into other African countries (Faulkner et al. 2017b), and most forestry pests that have been introduced to Africa were first recorded in South Africa (Graziosi et al. 2020). However, in 2016 and 2017, three alien pests of agriculture [red palm mite (Raoiella indica), tomato leaf miner (Tuta absoluta), and fall armyworm (Spodoptera frugiperda)] that were detected in South Africa for the first time had dispersed, either naturally or with the help of humans, into South Africa from other African countries where they had previously been introduced (Faulkner et al. 2020a). The increase in the movement of alien species between South Africa and other African countries (Faulkner et al. 2017b) is likely due to increasing trade and transport both between African countries and between African countries and the rest of the world. Changes to these processes and climate change could influence the intra-African movement of alien species in the future, and if the African Continental Free Trade Area (AfCFTA) is established the movement of alien species between African countries is likely to increase further. This is because imported goods will only be inspected for alien species at the first port of entry, and most African countries have limited capacity to respond to biosecurity threats (Early et al. 2016). It will be extremely difficult to prevent the dispersal of alien species within the continent once introduced (Faulkner et al. 2017b), and there could be conflicts of interest if some countries could benefit from the introduction of a species that could be harmful in other countries (Faulkner et al. 2020b). A co-ordinated regional response to alien species introductions is required to better manage the introduction and dispersal of alien species in Africa (Faulkner et al. 2017b; Graziosi et al. 2020; Sileshi et al. 2019). Movement of alien species within Africa Box 2.1 tomato leaf miner (Tuta absoluta) - D. Visser 16 2.5. Trends in pathway indicators Indicator Trend (confidence) Desired trend Current status Outlook 1. Introduction pathway prominence (Medium) Not applicable There has been little change since the first report. 11 introduction pathways play a major socio-economic role. There is no desired trend for introduction pathway prominence as it is largely a function of global trade and travel. However, there is a need to track pathways and trends in trade to ensure that interventions respond to these trends, otherwise potentially harmful alien taxa will continue to be introduced. For example, growth in intra-African trade will increase the risk of importing invasive taxa to South Africa (and exporting them to other African countries). 2. Introduction rates (Low) Not applicable (for regulated taxa) (for unregulated taxa) There has been little change since the first report, and alien taxa continue to be intentionally and accidentally introduced through a wide variety of pathways. During the 2017–2019 period, new taxa were legally introduced for biological control, and were accidentally introduced through the timber trade, shipping, as contaminants on imported animals, and through natural dispersal from other African countries where they had previously been introduced. 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. Therefore, no specific trend is desirable for regulated taxa, but what is desirable is that a process is in place to regulate them. There has been progress on this issue (see Chapter 5). The rate of introduction of unregulated taxa will increase as the volume of trade and travel increases. The rate of introduction of unregulated taxa is, however, sensitive to the intensiveness of survey activities and is likely to be relatively unresponsive to changes in actual introductions.This is because many accidental introductions can go undetected for a long time and are only discovered once a specialist survey is undertaken (cf. PSHB). Unless pathways are identified, prioritised, and managed, potentially harmful alien taxa will continue to be accidentally and illegally introduced. no change; increase; decrease 17 Indicator Trend (confidence) Desired trend Current status Outlook 3. Withincountry pathway prominence Not assessed Not applicable Information was only obtained for a few pathways. Many pathways are likely playing a socio-economic role within the country, but the extent of this role and how it has changed since the first report is not known. There is no desired trend for within-country pathway prominence as it is a function of internal trade and transport. However, 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. Within-country dispersal rates Not assessed (for regulated taxa) Not applicable (for unregulated taxa) National-scale data has yet to be collated, but information was available for alien plant taxa in South Africa’s national parks. Most alien plants were intentionally introduced to national parks as ornamental plants or were dispersed by rivers and animals, and many utilised multiple pathways. Increases in the volume of trade and travel will lead to increases in the within-country dispersal rates of taxa known to be invasive, or that are considered likely to become invasive. The spread of regulated invasive taxa is of particular concern, and while other taxa might also spread, it is not clear whether this should be a concern. Unless pathways that facilitate the withincountry dispersal of regulated 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. High level indicator A. Rate of unregulated introduction of new species (Low) Between 2010 and 2019 approximately 3 new taxa were introduced per year either accidentally or intentionally but illegally. This was lower than the estimated rate during the previous decade (~ 5 per year). Despite the apparent recent decline in introductions, opportunities for the introduction of alien species are expected to increase as the volume of trade and travel increases. Whether this will result in the introduction of more invasive species will depend on the degree to which key pathways are identified and prioritised for management. Improvements to inspection, management, and incursion response at border would strengthen South Africa’s biosecurity. no change; increase; decrease 18 white garden snail (Theba pisana) - C. Griffiths 19 3 SPECIES Key findings: • The number of alien species in South Africa has increased from 1637 to 1880. A notable new invasive species that is predicted to have massive impacts is the polyphagous shot hole borer (PSHB). • The impacts of 215 invasive alien species have been formally assessed, seven of these were found to cause major or massive environmental impacts, and one was found to cause major socio-economic impacts. Impact assessments are needed for the other alien species but in many cases there is a lack of reliable data. • A national registry of alien species will help clarify which species are legally in the country, consolidate information on the status of invasive species, and provide an important reference resource for the biodiversity and broader community. This second report represents a major step towards this, in particular by improving how data are presented, how changes are tracked, and ensuring information is presented in a manner consistent with international best-practice. Key gaps (shared with Chapter 4: Sites): • Data on the distribution and abundance of alien species need to be collected, collated, and integrated into national and global databases to facilitate the planning of interventions. • The systematic quantification of the impacts of biological invasions would: facilitate the prioritisation of interventions targeting particular species and particular sites; provide the justification for government investment to control biological invasions; and provide important background to communicate the issue to society. Authors: Tsungai A. Zengeya, John R. Wilson Contributing Authors: Katelyn Faulkner, Lesley Henderson, Nonkazimulo Mdidimba, Siyasanga Miza, Musa Mlambo, Xoliswa Ndeleni, Trudy Paap, Tamara Robinson, Pieter Winter Common myna (Acridotheres tristis) - R. Taylor 26 Indicator Trend (confidence) Desired trend Current status Outlook 7. Abundance of alien species Not assessed No new data were available on the abundance of alien species Some exploratory work has been initiated to estimate the abundance of alien plant species using remote sensing, but there are still very few reliable data sources. Understanding trends in abundance is important if the effectiveness of management interventions are to be monitored, and the magnitude of future impacts predicted. 8. Impact of alien species (Medium) 215 species have been assessed using an evidence-based framework, and 7 species have been reported to cause major to massive impacts using EICAT and 1 using SEICAT. However, there was no reliable data for the majority of the assessed species. This represents a shift from expert-based assessments of impact of alien species to evidence-based assessments. This remains a major gap where detailed research is needed. Unless the impacts of invasive species can be quantified, attempts to regulate them will remain contentious in many cases. Head-line indicator B. Number of invasive species that have major impacts Not assessed In the first report, 107 alien species were identified by experts as particularly damaging. A process is under way to formally assess all invasive species using the IUCN’s EICAT scheme. So far 215 species have been assessed, and eight found to cause major to massive impacts (five fish, two grasses, and one mammal species). However in many cases there was a lack of reliable data. The number of alien species recorded to have major or massive negative impacts will increase as more species are formally assessed. The formal assessment of the impact of alien species provides the rationale for regulation and management, can improve compliance and implementation of intervention measures, and assist to resolve conflicts. However, impact assessments are hampered by a lack of reliable data for most species. If this situation persists, regulations will continue to be vulnerable to legal challenges. It is very difficult to control invasive species with major impacts in a way that will reduce such impacts to moderate or minor, but this has arguably been achieved by biological control for over 30 invasive taxa. On-going investment in biological control will likely result in more such successes. If alien species that currently have moderate or minor impacts are prevented from increasing in abundance and extent to the point where they have major impacts or, where feasible, such species are eradicated from South Africa, then significant returns on investment may also be made. no change; increase; decrease 27 4 SITES Key findings: • Invasive species richness is highest in the Fynbos, Savanna, and Grassland biomes (251, 241, and 230 species, respectively) and lowest in the Desert (9 species) and Forest (10 species) biomes. Estimated increases in species richness range from 2 to 78 in individual biomes. The Agulhas marine ecoregion has the most invasive species followed by the Southern Benguela and Natal ecoregions (41, 39, and 25 species, respectively). • Relative abundance of invasive plants has been estimated for some protected areas. Invasion in South Africa’s National Parks were found to be minor to moderate. However, the reliability of these estimates is low and fine scale systematic surveys have recorded substantially different estimates. Should the criteria for management plans be amended by the DFFtE to include a simple standardised monitoring protocol, then it should be possible to track these values over time. • Invasions cause major impacts through biodiversity loss, reducing water resources, reducing the productivity of rangelands, and by exacerbating fires. For example, annual surface water runoff has been reduced by between 1 and 321 m³ per primary catchment, and carrying capacity has been reduced by 19 000 large livestock units in the grassland biome. Key gaps (shared with Chapter 3: Species): • Data on the distribution and abundance of alien species need to be collected, collated, and integrated into national and global databases to facilitate the planning of interventions. • The systematic quantification of the impacts of biological invasions would: facilitate the prioritisation of interventions targeting particular species and particular sites; provide the justification for government investment to control biological invasions; and provide important background to communicate the issue to society. Authors: Tsungai A. Zengeya, Katelyn T. Faulkner, Tendamudzimu Munyai, Brian W. van Wilgen, John R. Wilson Contributing Authors: Johan Baard, Nicholas Cole, Nicola J. van Wilgen clearing of mesquite (Proposis sp.) in the Northern CapeJ. Barnard 28 9. Alien species richness 10. Relative invasive abundance 11. Impact of invasions SITES HIGH LEVEL C E major impacts from invasions 4.1. Alien species richness The alien species reported from South Africa in this second report are distributed across the country, with most broad-scale administrative units and biogeographical regions being invaded by a variety of species (Table 4.1). The recorded invasive species richness has increased by 0–4.5% in individual provinces, with the highest invasive species richness still in Mpumalanga, while the Northern Cape still has the lowest richness (Table 4.1A). Invasive species richness is highest in the Fynbos, Savanna, and Grassland biomes and lowest in the Desert and Forest biomes (Table 4.1B). Only 2 of the 22 water management areas have no recorded invasive animal species, but the other water management areas only have at most 4 species recorded (Table 4.1C). 56 invasive species have been recorded in South Africa’s marine ecoregions, with the highest richness being recorded in the Agulhas and Southern Benguela ecoregions. To date, no invasive species have been recorded offshore or in the ocean around the Prince Edward Islands (Table 4.1D). Table 4.1. Invasive species richness in South Africa for different broad-scale administrative units and biogeographical regions. The estimates of change are made with low confidence because most reported increases arise from the formal recording of species that have probably been present for some time. Data are South African records available from GBIF (https://www.gbif.org/) and the Southern African Plant Invaders Atlas (SAPIA) for continental South Africa, from Robinson et al. (2020) for marine eco-regions, and from Greve et al. (2020) for the Prince Edward Islands. NA = not assessed. See Supplementary Tables S4.1–4.3 for more details, Appendix 1 for the data sources, and Appendix 2 for the full species list. A) Invasive terrestrial species and invasive freshwater plant species richness per province. Province / Region End of 2016 End of 2019 Change Eastern Cape 142 148 +6 Free State 85 88 +3 Gauteng 131 133 +2 KwaZulu-Natal 182 184 +2 Limpopo 103 106 +3 Mpumalanga 204 210 +6 Northern Cape 64 64 0 North West 81 81 0 Western Cape 178 186 +8 Prince Edward Islands NA 35 NA Indicators covered in this chapter: 29 B) Invasive terrestrial species and invasive freshwater plant species richness per biome. Biome End of 2016 End of 2019 Change Albany Thicket 86 108 +22 Desert 7 9 +2 Fynbos 173 251 +78 Forest 7 10 +3 Grassland 177 230 +53 Indian Ocean Coastal Belt 127 156 +29 Nama-Karoo 61 76 +15 Savanna 197 241 +44 Succulent Karoo 47 55 +8 C) Invasive freshwater animal species richness per water management area. Water management area End of 2019 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 30 D) Marine invasive species richness per marine ecoregion. Marine ecoregion End of 2019 Agulhas 41 Delagoa 8 Natal 25 Prince Edward Island marine (offshore) 0 Southeast Atlantic (offshore) 0 Southern Benguela 39 Southwest Indian (offshore) 0 Data at a finer-spatial scale are available for invasive bird and plant species [one quarter-degree grid cell (qdgc) is 630–710 km² at the latitudes of South Africa]. Recorded invasive bird species richness appears to be highest around major urban centres (Figure 4.1A). This is likely because most alien bird species are commensal with humans, most were first introduced to urban centres, and because of greater sampling around urban areas. There have been few changes in invasive bird species richness at this scale with 15 qdgcs showing an increase in one bird species and 1 qdgc showing an increase in two species (Figure 4.1B). Invasive plant species richness is similarly high around urban areas (Figure 4.1C). Parts of the country have shown notable increases in invasive plant species richness (Figure 4.1D), however these increases are a direct result of a dedicated road-side survey from Pretoria through the Free-State to the southern Cape that was conducted in March 2018 as part of the SAPIA project (Henderson 2018). This suggests that current patterns of invasive plant richness are still highly sensitive to sampling effort. Data on invasive species richness of other taxonomic groups have not been updated since the first report. 31 A) Invasive bird species richness B) Changes in invasive bird species richness D) Changes in invasive plant species richness C) Invasive plant species richness Figure 4.1. Invasive bird and plant species richness in South Africa at the scale of a quarter-degree grid-cell as of December 2019. Changes are shown for the period 2017– 2019. See Figure S4.1 for more details. Reliable spatial estimates of richness were not available for all alien species, although alien species richness has been documented for some urban areas (Box 4.1) and for some protected areas (see section 4.2). 32 4.2. Relative invasive abundance The distribution and cover of invasive plants have been estimated for some protected areas¹ (e.g. Baard & Kraaij 2019; Cheney et al. 2018; van Wilgen et al. 2016; van Wilgen & Herbst 2017). Estimates of relative abundance were provided by Cape Nature and Ezemvelo KwaZulu-Natal Wildlife for all of their protected areas for the first report (see Box 5.2 and Figure A1.9 in SANBI and CIB 2018). These estimates were not updated for the second report. However, estimates of relative abundance for the second report were provided by the South African National Parks. While no protected areas are currently dominated by invasive plants (Table 4.2), several important invasions are apparent. For example, parts of the Garden Route National Park are dominated by invasive plants although overall the park is only moderately invaded. The reliability of such estimates is, however, questionable, as fine-scale systematic surveys can produce estimates that are substantially different from datasets used for planning alien plant control operations (Cheney et al. 2018). Nonetheless carefully considered broad-scale estimates of relative abundance repeated over time would allow trends to be tracked with a moderate level of confidence in future reports. 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 developed by the DFFtE in terms of the NEM:BA A&IS Regulations. Table 4.2. Estimates of relative invasive abundance in South Africa’s protected areas based on percentage plant cover. Alien-free means that no alien species are recorded in the protected area. Relative invasive abundance Number of Cape Nature’s protected areas (first report) Number of Ezemvelo KwaZulu-Natal Wildlife’s protected areas (first report) Number of SANPark’s protected areas (second report) Alien-free 0 1 0 Minor <2% 19 59 14 Moderate 2–10% 4 39 2 Extensive 10–50% 1 22 0 Dominant >50% 0 0 0 1South Africa has an extensive network of protected areas, which are either National Parks (managed by South African National Parks) or provincial reserves (managed by the provincial departments responsible for environmental conservation in each of the nine provinces) a section of the Garden Route National Park showing a dominant invasion by alien Pinus species - B. van Wilgen 33 4.3. Impact of invasions The results of several studies that assessed the impacts of biological invasions at a number of scales have been published since the first report (Table 4.3). These studies strengthen the evidence base for quantifying the magnitude of impacts, but overall levels of confidence in these estimates remain low. This is because several of the studies are based on models in which assumptions have had to be made that were acknowledged to be tenuous, and results still have to be extrapolated from small scales (e.g. several hectares) to larger scales (e.g. provinces, biomes or water management areas). The impacts at particular sites are, however, increasingly well understood (e.g. urban areas, Box 4.1). Table 4.3. Findings of research studies published in the period 2017–2019 with comparisons to indicator values from the first report where relevant. Affected sector Value in the first report Value in the second report Difference Reference Biodiversity Moderate impacts on biodiversity intactness for South Africa Major impacts on biodiversity over 10–50ha Scales differ, so not comparable Mostert et al. 2017 Biodiversity Not assessed All major taxonomic groups have species directly threatened by invasions according to Red List assessments. Invasive species are the leading pressure on native amphibians and freshwater fishes. Invasive species were the primary driver of some species, especially plants and butterflies, being listed in higher categories of threat. Not applicable SANBI 2019 (The National Biodiversity Assessment) Soil Not assessed Moderate impacts through soil nutrient enrichment following invasion over 10–50ha Not applicable Nsikani et al. 2017, 2018 Fire severity Not assessed Major impacts on fire severity over ~10 qdgcs Not applicable Kraaij et al. 2018 Water runoff Annual Surface water runoff reduced by 1–321 million m3 per primary catchment Annual Surface water runoff reduced by 1.15–2.11, and 7.98 million m3 for two catchments No change Preston et al. 2018 Rangeland carrying capacity Reduction in carrying capacity of 19000 large livestock units in the grassland biome Reduction in carrying capacity of 75% (from 5 to 1.25 large livestock units on 10ha) Scales differ, so not comparable Yapi et al. 2018 Monetary value of impacts on sites Annual losses of ZAR 5 864 million and ZAR 337 million for water resources and livestock production respectively for South Africa Losses have net present value (NPV) of ZAR34 and 1.9 billion for water resources and livestock production respectively for South Africa Annual losses reported in the first report would have to be converted to NPV (6% discount rate over 25 years) to be able to compare estimates. Stafford et al. 2017 34 Urban invasions Box 4.1 Invasions in urban areas are particularly noteworthy both given the legal requirement for municipalities to report on biological invasions, and as urban areas are often the initial sites for introductions from which invasions spread (McLean et al. 2017; Padayachee et al. 2017). There has been significant research on urban invasions since the first report, with the publication of a special issue of the journal Biological Invasions in December 2017 (Gaertner et al. 2017a; https:// link.springer.com/journal/10530/19/12/page/1), and the development of the Global Urban Biological Invasions Consortium of which South Africa is a part (https://cubes-labs.com/gubic/). Protocols for mapping alien plants in towns (McLean et al. 2018) and identifying sites for contingency planning (Padayachee et al. 2019) have been developed; a framework has been proposed to understand the urban-natural gradient as a filter for invasions (Holmes et al. 2018); and decision support tools to assist with management planning (Gaertner et al. 2017b) and prioritisation have been developed (Potgieter et al. 2018). Moreover, we now have a better understanding of the role of urban areas as hotspots and sentinel sites for invasions (Paap et al. 2017), and of both perceived and realised impacts (Potgieter et al. 2018, 2019a, 2019b, 2020). There have also been significant investments in control operations (in particular by the City of Cape Town and eThekwini) focusing on both plants and animals (Davies et al. 2020). Maderia vine (Anredera cordifolia) - N. Cole 35 4.4. Trends in site indicators Indicator Trend (confidence) Desired trend Current status Outlook 9. Alien species richness (Low) Invasive bird and plant species richness remain high around major urban centres with minimal changes except for some apparent changes that are probably due to localised sampling efforts. Invasive species richness in marine ecoregions was assessed for the first time and the highest invasive species richness was recorded in the Agulhas (41 alien species), Southern Benguela (39 species), and Natal (25 species) ecoregions. 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 Not assessed There are no country-wide estimates for the relative abundance of invasive species, but estimates for invasive plants in protected areas managed by the South African National Parks indicate invasions are minor to moderate. However, the reliability of these estimates is low, as some fine scale systematic surveys have recorded substantially different estimates. 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 DFFtE 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. Impact of invasions Not assessed Several studies have explored the impact of invasions at particular sites since 2017, but these were either done using different approaches or were done at different scales and are therefore unsuitable for drawing robust general conclusions. However, it is clear that alien species continue to cause major impacts through biodiversity loss, reductions in water resources, and reductions in rangeland productivity. In addition, alien species exacerbate fires and alter important ecosystem functions such as nutrient dynamics. 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. High-level indicator C. Extent of area that suffers major impacts from invasions Not assessed Biological invasions continue to cause major impacts on both rural and urban communities by, amongst other things, reducing South Africa’s water resources, degrading pastureland, and exacerbating fires. Biological invasions continue to contribute to biodiversity loss and ecosystem change. 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. no change; increase; decrease 42 1995/96 1996/97 1997/98 1998/99 1999/00 2000/01 2001/02 2002/03 2003/04 2004/05 2005/06 2006/07 2007/08 2008/09 2009/10 2010/11 2011/12 2012/13 2013/14 2014/15 2015/16 2016/17 2017/18 2018/19 0 200 400 600 800 1000 1200 1400 Money spent (ZAR millions) Financial year Figure 5.1. The amount of money spent (unadjusted for inflation) by the DFFtE’s Natural Resource Management programmes on biological invasions in South Africa. Data are from annual reports as summarised on the site https://sites.google.com/site/wfwplanning downloaded December 2019; the financial year is from 1 April to 31 March. 5.2. Input – money spent The DFFtE’s Natural Resource Management programmes continue to spend a significant amount of money on controlling biological invasions, well over a billion ZAR per year (Figure 5.1). However, while the absolute annual spending by DFFtE has stayed fairly constant over the period 2012–2019, in real terms this represents a decline. The expenditure is, however, an underestimate, as it does not take into account funds allocated to the control of invasive species by, for example, other government departments, national and provincial conservation bodies, metros and municipalities, NGOs, and the private sector. With respect to spending on individual species, information supplied by a range of implementing agencies indicated that at least 237 invasive species were targeted for management (Table 5.1, for full details see Tables S5.6 and S5.9). The spending per species is highly skewed – 45% of the money was spent on controlling black wattle (Acacia mearnsii), and 77.2% of all money spent was directed at only ten species (Figure 5.2). 43 Table 5.1. Spending by selected organisations on the management of invasive species in South Africa in 2018 and 2019. Note that the same species can be targeted by several agencies (i.e. the total number of species targeted in South Africa is not the sum of the third column). These costs will generally include some overheads, though it is not clear if this is full cost accounting. Organisation Money spent (ZAR) Number of species Notes DFFtE Natural Resource Management (NRM) programmes 662012 652 108 The value includes the total expended by Working for Water on contracts to implementing agents, plus 30% to cover overheads. South African National Parks 180 535 11 The species treated are additional to those funded by WfW in National Parks. CapeNature 4 093 214 21 The species treated are additional to those funded by WfW in CapeNature`s protected areas. Agricultural Research Council and the Centre for Biological Control at Rhodes University 111133 897 68 Funding for biological control research and implementation provided by NRM SANBI 20170000 63 Investment to assess the feasibility of eradication and attempt eradication provided by NRM BioSecurity. Figure 5.2. The amount of money spent in 2018 and 2019 by the DFFtE on controlling individual invasive plant taxa. There are 227 other taxa. Lantana camara Arundo donax Parthenium hysterophorus Prosopis spp. Caesalpinia decapetala Acacia cyclops Acacia dealbata Campuloclinium macrocephalum Acacia saligna Acacia mearnsii Money spent in 2018 and 2019 (millions of ZAR) 0 100 200 300 Other taxa 44 5.3. Input – planning coverage There has been no change to the proportion of pathways of introduction with management plans in place ~ (80%). There has been no attempt to prioritise pathways for management, and consequently no formal management plans for pathways have been developed by the DFFtE. Although ballast water management plans have been drafted for some South African ports, they appear not to have been implemented (Calitz 2012). In order to manage the species that are transported on the hulls of ships, the Transnet Ports Authority plans to introduce in-water hull cleaning, however, it appears that this has not yet been put into practice. See Supplementary Material section S5.7 for more details. As highlighted in the first report, section 75(5) of NEM:BA empowers the Minister to establish a body to co-ordinate species-specific management plans, but no evidence was found that such a body had been established. No species have dedicated management plans in place. Those listed in the first report for pompom weed (Campuloclinium macrocephalum) and parthenium weed (Parthenium hysterophorus), and for taxa in the genera Acacia and Prosopis, and in the family Cactaceae are yet to be formally approved. Species-specific eradication management plans have been prepared for some species (Table S5.6), but none have yet been formally approved, though it is not clear what the process for this is. In addition, the quality of the plans has not yet been assessed. A detailed plan for the eradication of house mouse (Mus musculus) from Marion Island has also recently been developed (Preston et al. 2019). Since the first report, 25 new site management plans covering 648 294 hectares have been submitted, increasing the proportion of sites covered by management plans to 4.5% of the country (Table S5.8). Plans for the Maloti Drakensberg Conservation and Development Area (312 105 hectares¹), Buffalo City Metropolitan Municipality (250 000 hectares), and uMdoni Local Municipality (23 800 hectares) constitute the largest additions. Three site management plans were submitted by private landowners, two of which were submitted pursuant to the issuing of pre-directives on the relevant landowners. The site management plans were assessed using the guidelines outlined in the first report (see section 7.4 in SANBI and CIB 2018). The majority (84%) of the new plans were assessed as partially adequate. Three plans were found to be adequate and one was inadequate. Most site management plans identified the alien plant species that were present, detailed general measures that can be taken for their control, and described invaded sites. However, few of the plans linked the measures to a specific timeframe and budget or reviewed the efficacy of previous control efforts. 5.4. Output – pathways treated Since the first report there has been no change to the proportion of pathways requiring management that are being managed (77%). Inspection operations by the DFFtE at OR Tambo International Airport have been expanded and now cover a greater number of locations including the passenger terminals, cargo terminal, and mail centre. Environmental management inspectors use the ‘Lifescanner’ application to assist with identifying species at ports of entry, and in cases where the inspector cannot identify the taxon, a DNA analysis (performed off-site at a laboratory) is used to assess whether there is compliance. This analysis can take some time and in instances of compliance the imported specimens are only released to their owner once the results are returned. This also leads to a delay in seizures and arrests. However, a new tool, the labin-a-box, which was recently developed, might in future enable inspectors to perform a DNA analysis at the port of entry, and reduce the time required to assess compliance. During the 2017/2018 and 2018/2019 financial years the DALRRD inspected more than 180 000 animal and plant product import permits, and 3 658 animal and plant imports. Additionally, over 12 000 plant import samples were tested for quarantine pests by Plant Inspection Services. See Supplementary Material section S5.8 for further details. 1The Maloti Drakensberg Conservation and Development Area (312 105 hectares) is the transfrontier conservation area that straddles the northeastern border between Lesotho and South Africa. The coverage of the site management plan reported here only reflects the extent to which the site management plan covers the South African part. 45 5.5. Output – species treated Without formal species-specific plans in place, it is not possible to evaluate the degree to which management is targeting the species that need to be treated. Of the 556 listed invasive taxa, 189 taxa (34%) were subjected to some form of management in 2018 and 2019. By comparison, 136 taxa (24%) were reported to be subject to regular management in the first report (Table 5.2, see Table S5.9 for a full list). It is possible that, for some taxa, the need for further management interventions might have been assessed and deemed to be not needed. Table 5.2. Number of taxa¹ that were subjected to management interventions, by regulatory or other category. NA = not applicable. See Supplementary Table S5.9 for a full list. Regulatory or other category Description Number of species or taxa targeted Number of species or taxa listed 1a Taxa that are targets for eradication 38 52 1b Taxa that must be controlled 98 248 2Taxa where cultivation, ownership and trade are allowed subject to the issuing of a permit, and that must be controlled in the absence of a permit 17 75 3Taxa that are subject to exemptions, but that cannot be further traded or propagated, and otherwise must be controlled 6 44 Contextspecific Taxa that are listed in different categories depending on the area or ecosystem in which they are found 30 137 Prohibited Taxa that are assumed to not yet be in the country, and for which a permit may not be issued 1 560 SUSPECT Acronym for ‘Species Under Surveillance for Possible Eradication or Containment Targeting’, not listed in the regulations 21 NA Unlisted alien species Alien taxa that are not listed in the regulations 23 NA Unlisted extralimital species Taxa native to a part of South Africa that have been translocated outside of their natural distribution range, but that are not listed in the regulations 3 NA A number of new species-specific control interventions have been reported (Table 5.3). The application of treatments to remove invasive freshwater fishes has been very promising, and there are several notable success stories where native biodiversity has recovered within a few years of treatment. These projects involved a range of stakeholders and rigorous monitoring to assess whether there was any adverse impact of the treatment. This suggests that this technique is viable in South Africa. Four new biological control agents of invasive plants were released in South Africa during 2017–2019 and three were released in 2016 that were not reported on in the first report (Table S5.10). These were released against the following targets: Bailey’s wattle (Acacia baileyana) and green wattle (A. decurrens) [also attacks silver wattle (A. dealbata) and pearl acacia (A. podalyriifolia)], Madeira vine (Anredera cordifolia), dense water weed (Egeria densa), lantana (Lantana camara), Australian albizia (Paraserianthes lophantha), Mexican sunflower (Tithonia diversifolia), and white-flowered wandering Jew (Tradescantia fluminensis). No new biological control agents were released against invasive animals or fungi. 1In some cases, a genus or family may be regulated instead of a species 46 Table 5.3. Invasive taxa for which management interventions were initiated in the period 2017–2019, or for which information not incorporated in the first report was obtained. See Supplementary Material section S5.2 for definitions of the legal listing categories of the NEM:BA A&IS Regulations. The ‘extent of treatment’ is the degree to which populations requiring management are being managed and the ‘quality of treatment’ is based on an assessment of the quality of intervention in terms of best practice as outlined in indicator 16, species treated. The ‘effectiveness of treatment’ and the ‘adverse impacts of treatment’ are scored as per indicator 19, effectiveness of species treatments. See the indicator factsheets supplementary to Wilson et al. (2018) for details. Scientific name Vernacular name Regulatory category Extent of treatment Quality of treatment Effectiveness of treatment Adverse impacts of treatment Notes Source Anas platyrhynchos mallard 2 Partial Adequate Effective Not recorded Localised removals of individuals are taking place at some sites. Management goals are not tightly defined, so that the level of success cannot be assessed. Davies et al. 2020 Australian Acacia species wattles 1b (A. saligna, A. cyclops, A. longifolia); 2 (A. mearnsii) Partial Partially adequate Effective Minimal Models based on data from Table Mountain National Park clearly demonstrate that the goal of achieving long-term control will not be achieved unless the efficiency of control projects is improved. Cheney et al. 2018 Carcinus maenas European shore crab 1b Partial Adequate Ineffective Minimal A management trial substantially reduced the population of crabs in one of the invaded harbours, however the population quickly rebounded once management ceased and so management would need to be sustained. Nation-wide eradication was considered not to be feasible. As the benefits of management are unclear and currently the likelihood of spread and impact appear low, it was recommended that no further control be employed at this stage. The traps caught other organisms as well as the intended target (crabs). The majority of this bycatch was released apparently unharmed once the traps were inspected, although some cormorants were caught in the traps and drowned. Mabin et al. 2017, 2020 Clarias gariepinus sharptooth catfish Not regulated Partial Partially adequate Ineffective Minimal The attempt at extirpation from one dam was not successful. Davies et al. 2020 47 Scientific name Vernacular name Regulatory category Extent of treatment Quality of treatment Effectiveness of treatment Adverse impacts of treatment Notes Source Corvus splendens house crow 1a Substantial Partially adequate Partially effective Minimal Attempts to extirpate the species from two cities have made good progress, but extirpation has not yet been achieved in either case. Control programmes have not been continuous and control becomes much more difficult when numbers are low (both as the crows learn quickly and as they change behaviour at low densities). The species is now present in two more coastal cities where management projects have not yet been initiated. The likelihood of re-colonisation has not been assessed, and so it is unclear if eradication is a feasible goal. Davies et al. 2020 Cyprinus carpio common carp Contextspecific Partial Inadequate Ineffective Not known The attempt at extirpation from one wetland was not successful. Davies et al. 2020 Micropterus punctulatus spotted bass Contextspecific Partial Adequate Permanent Major but transient; ~full recovery is apparent within a few years. The species was successfully extirpated from one stretch of river. Fish were captured by chasing them into gill nets or by catching them with hand nets. The remainder were removed using spearguns, seine nets, and by back-pack electrofishing. Three years after the extirpation, native fiery redfin (Pseudobarbus phlegethon) and Cape galaxias (Galaxias zebratus) were observed in pools where they had been absent during the bass invasion. van der Walt et al. 2019 Oncorhynchus mykiss rainbow trout Not regulated Partial Inadequate Ineffective Major but transient The attempt at extirpation from one stretch of river was not successful. Shelton et al. 2017 Procambarus clarkii red swamp crayfish Prohibited Partial Inadequate Ineffective Not known The attempt at extirpation from one dam was not successful. Nunes et al. 2017b Salvinia molesta Kariba weed 1b Complete Adequate Effective None Update on effectiveness of biological control (complete or substantial control was achieved at different sites). Martin et al. 2018 48 5.6. Output – sites treated A number of new site-specific control interventions have been identified (Table 5.4). In relation to private land, a person who is the owner of land on which a listed alien species occurs has a duty of care in relation to those species. They are required to notify the competent authority of the occurrence of such invasive species on their land; to take steps to control and eradicate the listed alien species and to prevent it from spreading; and to take all the steps required to prevent or minimise harm caused by the invasive species to biodiversity. In terms of regulation 13 of the A&IS Regulations, the Department is obligated to establish and maintain registers of notifications received from landowners and directives served on landowners for non-compliance with NEM:BA and the A&IS Regulations and to provide the DFFtE and SANBI with copies of those registers. SANBI has not been provided with any copies of such registers by the DFFtE. It is therefore unclear if any notices were received from landowners since the first report. However, details of directives and pre-directives issued in terms of the A&IS Regulations are recorded in the Department’s overall environmental compliance and enforcement registers. Information on the full number of pre-compliance notices, compliance notices, pre-directives or directives that have been issued subsequent to those reported in the first report were not made available (see Table S5.11 for a proposed format for presenting these data). The type of properties served with notices and directives for restricted activities with listed alien and invasive animal species were mainly private landowners and nurseries (Table S5.12). Enforcement action was also taken against some organs of state, such as municipalities, national departments, and management authorities of protected areas. Over the period 2017–2019, six non-compliance cases against private landowners were handed over to the National Prosecuting Authority (NPA) for criminal prosecution (Table S5.12). The NPA has secured one criminal conviction (Box 5.2, see p.52), while the other five cases are still pending. 5.7. Outcome – effectiveness of pathway treatments At the time of the first report, the effectiveness of pathway treatments could be estimated for 25 of the 44 pathways, and for all but one of these pathways there have been no changes to these estimates. However, for most pathways (61%) management appears to be either absent or ineffective. The effectiveness of pathway treatments can be estimated for the first time for several pathways. Listed alien species are being sold in nurseries (Cronin et al. 2017) and as part of the medicinal plant trade (Byrne et al. 2017), and undocumented bamboo species have been imported for a number of purposes related to the green economy [e.g. for biofuel and mine rehabilitation (Canavan et al. 2019)]. Furthermore, of the inspections performed by the DALRRD during the 2017/2018 and 2018/2019 financial years, 47% of the animal and plant product import permits inspected were non-compliant due to invalid documentation, contamination or the detection of quarantine pests; 8% of the animal and plant imports inspected were quarantined; and 62 quarantine pest interceptions were recorded by Plant Inspection Services [including Eriophyidae Aculus schlectendali and A. cf. wagnoni), Pseudomonas sp., and Paenibacillus larvae]. Therefore, for the eight pathways for which management effectiveness could be assessed for the first time, management appears to be either absent or ineffective (Table S5.13). Additionally, further research into the pet trade has highlighted that prohibited and regulated species are being sold (Nunes et al. 2017a; Nelufule, 2018), which supports the assessment in the first report that management of this pathway is either absent or ineffective. See the Supplementary Material section S5.11 for more details. 49 Table 5.4. Invaded sites for which management interventions have been initiated and/or assessed in 2017–2019 or where information from earlier years has been obtained. Site Purpose Quality of treatment Effectiveness of treatment Adverse impacts of treatment Management notes Source All South African National Parks Assessment of alien plant data, and its usefulness for supporting decision-making Partially adequate Effective Minor Multiple goals, onerous reporting requirements, and low-quality monitoring data hamper the ability to make informed (and adaptive) management decisions. Loftus 2013 Table Mountain National Park Assessment of impact of data accuracy on efficiency of alien plant control Partially adequate Effective Minor Low-quality data used to inform management led to poorly-informed management decisions and increased costs. Improving data quality would lead to cost-savings and more effective management. Cheney et al. 2018 Catchments of the City of Cape Town To reduce water loss from invaded catchment areas Partially adequate Effective Minor These projects are funded by two NGOs (The Nature Conservancy and WWF South Africa), in collaboration with DFFtE NRM programmes and CapeNature. No data are yet available on progress towards goals. Box S5.1 Berg River, Western Cape Assessment of mediumterm vegetation recovery after removal of Eucalyptus camaldulensis Partially adequate Effective Minor Native vegetation was on a positive recovery trajectory following removal of eucalypts, but the site is at risk of re-invasion. Ruwanza et al. 2018 Paardevlei and Die Oog wetland, Cape Town Extirpation of four species of alien fish from the wetlands Adequate Effective Major, but transient In 2005, Paardevlei was treated by aerial spraying of Rotenone and over 35 tons of fish, mostly common carp (Cyprinus carpio) were removed after treatment. The fish have not been detected since the termination of monitoring in 2014, so the operation appears to have succeeded. At Die Oog, Rotenone treatment was initiated in 2005. This successfully removed all the alien fish species and restored ecosystem functioning. The fish have not been detected since and the wetland is in a good condition and supports a number of native bird and amphibian species. Davies et al. 2020 Lourens River, Western Cape Extirpation of three species of alien fish from an off-stream dam Adequate Effective Major, but transient An off-stream dam in the Lourens River catchment was treated with Rotenone in 2005 to remove three alien fish species. Removal of the invasive species allowed for the establishment of a refuge population of native fish from the Lourens River. The extirpation was successful. Davies et al. 2020 50 5.8. Outcome – effectiveness of species treatments Most invasive species are subjected to mechanical and chemical control, but because the outcomes are not monitored, essentially the only information available on the effectiveness of species treatments is on those species targeted for eradication, or for biological control. No alien species has been formally declared as eradicated during the past three years (van Wilgen et al. 2020c). There are 42 alien plant species listed as category 1a for continental South Africa, i.e. are nation-wide eradication targets. However, only around a third of these species are still the focus of on-going control efforts aimed at eradication – many are suspected to be inappropriate targets for eradication (see Supplementary Material section S5.9). The mismatch between legal status and feasibility of eradication highlights the need to set eradication as the management goal only once a formal detailed assessment of eradication feasibility has been conducted. Such assessments require investment in delimitation and control trials. It is also clear that there is a substantial invasion debt in the country – many alien plants have only naturalised or invaded a few sites, and there are likely to be many that are still to be detected – a significant number of these new detections are likely to be suitable targets for eradication. Suitable monitoring data are not routinely collected so it is difficult to judge whether these eradication campaigns are making appropriate progress or what, if any, remedial measures are needed. The biological control of invasive plant species was assessed in the first report as being notably successful for a small number of species. A further study has confirmed this assessment for the invasive aquatic plant Kariba weed (Salvinia molesta) (Martin et al. 2018: Table 5.3). These authors noted that the average percentage cover of water bodies by S. molesta declined from 51–100% to 0–5% between 2003 and 2017. Observations suggested that biological control of S. molesta was most effective at small sites and more difficult at larger and shaded sites, and that in some cases repeat releases of the biological control agent would be required. The biological control community in South Africa conducts a comprehensive review of the effectiveness of biological control for addressing invasive plants, at roughly 10-year intervals. These reviews have been conducted three times, the most recent was published in 2011 (Moran et al. 2011). The fourth review, which will cover the period 2011 to 2020, is currently in preparation, and is expected to be published in 2021. 5.9. Outcome – effectiveness of site treatments As for the first report the effectiveness of site treatments has been evaluated for a few specific sites or projects (e.g. Table 5.4; Box 5.3, see p.53). In addition, limited information on the effectiveness of control operations was supplied by the DFFtE NRM programmes. The information available was based on a sample of 1 130 management units (individual areas on which alien plant clearing contracts were awarded between 1998 and 2018), drawn from 68 projects across all nine provinces. The sample covered approximately 217 000 ha, or about 5% of all management units in the country. Initial densities were recorded on each management unit, which was then subjected to initial clearing and a varying number of follow-up clearings (Figure S5.3). It is difficult to draw robust conclusions from this, as the outcomes of the interventions are not measured. In addition, the assessment is based on data records and not on assessments in the field. It appears that the treatments are moderately effective in less than half of the areas treated, and ineffective in the rest. In addition, the area covered by the management units is only a proportion of the site under management (for example a protected area or catchment), so no information on areas not covered by management units is available. 51 The proposed listing of rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta) as invasive species in terms of NEM:BA The proposed NEM:BA A&IS lists published in February 2018 included the addition of rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta) as category 2 invasive species, the implication being that a permit would be required for conducting a restricted activity involving those species. The proposed amendment, however, meant that permits were not required to possess fish, exercise physical control over them, or catch and release them. Nonetheless, the proposal was contentious (see for instance Stephen Coan (2014) ‘Trout safe for now’, The Witness [available at https://www.news24.com/news24/archives/witness/Trout-safe-for-now-20150430, accessed on 6 August 2019]. The Federation of South African Flyfishers (FOSAF) challenged the legal validity of the notice of intention to amend the invasive species list on procedural grounds. They requested the Court to, inter alia, declare that the notice was unlawful and that it be set aside on review. The litigation focussed on the public participation process that was followed by the Minister in publishing the proposed amendments, and not on the risks posed by the species themselves. The DFFtE (the DEA at that time) had conducted evaluations of the risk posed by these species, and these were published on the DFFtE’s website during the public participation process¹. As of the end of June 2020, the litigation had not yet been finalised. Box 5.1 1https://www.environment.gov.za/extensiononpubliccommenting rainbow trout (Oncorhynchus mykiss) - Cape Nature 58 vermiculated sailfin catfish (Pterygoplichthys disjunctivus) - R. Karsing 59 6 GAPS Key findings: • The indicators developed for this report need to be tested and aligned to other government reporting processes. • There is insufficient information on how invasive species move and are moved around South Africa. A system to track within-country dispersal is required if South Africa is to manage the spread of invasive species. • Data on the distribution and abundance of alien species need to be collected, collated, and integrated into national and global databases to facilitate the planning of interventions. • The systematic quantification of the impacts of biological invasions is needed to facilitate the prioritisation of interventions, provide a defensible rationale to underpin government investment, and provide background to efforts to communicate the severity of the issue. • A comprehensive policy, and a strategy to implement such a policy, is needed to guide interventions on biological invasions in South Africa. • The absence of formal programmes to monitor the effectiveness of interventions in terms of outputs and outcomes means that the efficacy of control cannot be demonstrated, control measures cannot be compared and improved, and it is not clear whether progress is being made to reduce the negative impacts of invasions. Authors: John R. Wilson, Katelyn T. Faulkner, Tendamudzimu Munyai, Marthán Theart, Brian W. van Wilgen, Tsungai A. Zengeya setting traps for European shore crab (Carcinus maenas) as part of a management trial - T. Robinson 60 6.1. Process for identifying gaps In the first report, gaps affecting the ability to report on both biological invasions and on the effectiveness of interventions were identified and solutions were proposed. Gaps were identified for each indicator, and the progress to fill these gaps is outlined in Table S6.1. A recent comprehensive overview of biological invasions in South Africa (van Wilgen et al. 2020a) also highlighted factors that facilitate or hinder research and management. These are summarised in Table S6.2. Gaps were also identified during the production and review of this report (see Supplementary Material section S6). Based on these sources six key gaps were identified and are discussed here. 6.2. Indicators – improving how invasions are measured and providing a link to other reports While the theory and framework behind the indicators has been published (Wilson et al. 2018), there has been no explicit test of indicator performance. A method of mapping or aligning the indicators used in this reporting process to global initiatives on monitoring and reporting on biological invasions and to national reporting processes on broader topics (e.g. conservation or global change) is needed. 6.3. Pathways – tracking invasions across South Africa Information on how and why alien species are spreading within South Africa needs to be collated and evaluated if important within-country dispersal pathways are to be identified and managed. This will require the development of a framework to categorise such pathways as there are substantive quantitative and qualitative differences between introductions to the country and within-country dispersal (e.g. seeds of a horticultural species might be imported, screened on entry, and grown at a few nurseries; but once in South Africa, mature plants, cut flowers, and packets of seed might be sent to shops all over the country and sold on to many different people). Information recorded in the literature and other data sources (e.g. permits issued for interprovincial movement of alien species) will provide valuable data, but explicit monitoring might also be required. Research projects that focus on specific groups or parts of the country [e.g. on plants in South African National Parks (Foxcroft et al. 2019)] have provided some valuable information, but nationwide studies are in the early stages. monitoring fringed wattle (Acacia fimbriata) as part of an eradication attempt - J. Wilson 61 Without this information the pathways of dispersal that need to be managed cannot be identified, the interventions required to manage the within-country movement of alien species cannot be determined, and the effectiveness of the interventions that are currently in place (e.g. provincial permitting systems and restrictions on the movement of certain plants to prevent the spread of agricultural pests) cannot be assessed. In the absence of such control, invasive species, once established in the country, will continue to spread rapidly and impacts will increase. 6.4. Species & Sites – mapping invasions in space and over time Various atlassing projects are recording alien species on an ongoing basis (e.g. the government-funded Southern African Plant Invaders Atlas; and the South African National Bird Atlas). Ensuring the long-term sustainability of these is a priority. Much more still needs to be done to integrate these datasets with citizen science platforms, and to consider other taxa that are not currently covered by a specific atlassing project. In terms of determining the extent of plant invasions at particular sites, some exploratory work has been initiated on remote sensing, and some general guidelines are available on the types of data that need to be collected (e.g. Cheney et al. 2018). However, there are still very few reliable data sources on the relative abundance (cover, biomass or population size) of alien species at specific sites. A process to source and interpret data from national and provincial conservation agencies will be needed if change over time is to be tracked. Without detailed maps at national and local scales, estimates of the impact of invasions will remain crude, it is not possible to appropriately prioritise interventions across sites, and the ability to adapt interventions to respond more efficiently to invasions before they become widespread and damaging will be limited. 6.5. Species & Sites – determining the impacts and costs For the government to continue to invest substantial resources in managing biological invasions the benefits that interventions bring in alleviating the negative impacts caused to all sectors of South African society and to the country’s unique biodiversity must be clearly documented. Data on impacts are essential if control measures are to be prioritised and to track the effectiveness of interventions (e.g. in terms of increasing the resilience of South African cities, towns, and rural communities to droughts and fires; ensuring agricultural sustainability; and protecting our natural capital for future generations). The impacts of alien species presented in this second report are based on assessments of available data using international best practice (i.e. EICAT and SEICAT). This represents a significant advance from the assessments of impact in the first report that were based solely on expert opinion. This process needs to be completed. A systematic method for assessing the impacts of biological invasions at a site is needed (i.e. the combined impacts of all alien species present). Such assessments will require directed research to estimate the impacts of biological invasions in economic and social terms (De Lange & van Wilgen 2010; Shackleton et al. 2017; Witt et al. 2019). Consideration should also be given to the value of long-term monitoring to track impacts and how they change in response to different interventions. 62 6.6. Interventions – the need for an over-arching policy and strategy South Africa does not currently have a comprehensive overarching national government policy on biological invasions. This ‘policy vacuum’ has been flagged as an important factor limiting the effectiveness of past efforts to control biological invasions (Lukey & Hall 2020). A comprehensive, evidence-based policy on biological invasions would clarify the government’s position, guide decision-makers when implementing legislation, and assist the legislature when making and amending relevant laws. Such a policy would also provide a vision for what South Africa aspires to regarding biological invasions (Wilson et al. 2020). If the policy were in place, it would provide a structure for coordination, a basis for strategies and implementation plans, and guide monitoring and reporting by all affected parties. A better understanding of South Africa’s goals in respect of the management of biological invasions is critical for devising shortand medium-term implementation plans, estimating the annual budget required for giving effect to those implementation plans, and monitoring and reporting on the fulfilment of implementation plans. An additional consequence of there being no comprehensive policy or strategy addressing biological invasions in South Africa is that there is no or little intergovernmental coordination among environmental authorities and other organs of state responsible for biological invasions (e.g. the national departments responsible for the environment, agriculture, water and health, transport, and provincial conservation departments). These organs of state are responsible for the administration of various Acts that deal with the management of biological invasions, such as the Conservation of Agricultural Resources Act, 1983; Agricultural Pests Act, 1983; Animal Diseases Act, 1984; and the Animal Health Act, 2002. There is, however, little evidence that these organs of state have taken steps to ensure that the legislation they administer are is aligned and that monitoring and enforcement actions are streamlined to ensure better results. At a narrow level the lack of a policy poses a challenge for reporting on the status of biological invasions, but ultimately it negatively impacts the effectiveness of interventions. 6.7. Interventions – measuring the effectiveness of interventions Monitoring of interventions in terms of their outputs and outcomes is essential if their effectiveness is to be assessed and for management to improve by being adaptive. The effectiveness of interventions cannot be assessed (and improved) unless monitoring and reporting provides clearly documented information that is also made available for scrutiny. However, there appear to be no long-term plans for monitoring control interventions in terms of how they reduce biological invasions and their negative impacts, and it is unclear how the collection and reporting of accurate monitoring data is incentivised or penalised if it is not forthcoming. Moreover, while there are several research projects designed to assess the impact of particular policies, these are mostly still in the early stages. A systemic focus on monitoring and evaluation across the board would help both to demonstrate the impact of interventions and to increase the efficacy of the interventions themselves. Good data on monitoring costs money, but is a prerequisite for effective adaptive management, and, particularly in the light of the judicious use of new technologies, such monitoring would provide significant returns on investment. 63 ACKNOWLEDGEMENTS The drafting team would like to thank the members of the Reference and Advisory Committee for their guidance and advice on the process used to compile the report, and for reviewing several drafts of the report. These were Bob Scholes, Bonani Madikizela, Kay Montgomery, Mooketsa Ramasodi, Michael Braack, Peter Lukey, and Unathi Nkosi Heshula. We thank Bob Scholes for his additional role as review editor of the report. Additional inputs were received from John Donaldson, Amanda Driver, Jeffrey Manuel, Carol Poole, Sebataolo Rahlao, and Andrew Skowno. The following individuals provided comments for the first order draft of the status report: Adrian Armstrong, Lara Atkinson, Michael Braack, Christian Chimimba, Jenny Day, Theresa Frantz, Michelle Greve, Martin Hill, Dean Impson, Ian Kotze, Siyasanga Miza, Livhuwani Nnzeru, Tamara Robinson, Jasper Slingsby, Tony Swemmer, Andrew Turner, Andrew Wannenburgh, and Costas Zachariades. The second order draft was reviewed by two independent experts from South Africa (Andrew Turner and Adrian Armstrong), and one international expert (Helen Roy). Additional comments on the second order draft were received from Nicola van Wilgen-Bredenkamp, Chris Gowor, Martin Hill, Zanele Jele, Sabrina Kumschick, Khathutshelo Nelukalo, Priscilla Stiglingh, Riaan van der Walt, Jan Hendrik Venter, and Costas Zachariades. the status report drafting team (from left to right here, and the photographs below): John Wilson, Katelyn Faulkner, Brian van Wilgen, Tsungai Zengeya, Xoliswa Ndeleni, Marthán Theart, Tendamudzimu Munyai Siyasanga Miza Monica Klaas 64 guttural toad (Sclerophrys gutturalis) - N. Telford 65 REFERENCES • Airports Company South Africa. (2019). Passenger and aircraft statistics. (accessed 30 August 2019). http://www.airports.co.za/ business/statistics/aircraft-and-passenger. • Baard, J.A. & Kraaij, T. (2019). Use of a rapid roadside survey to detect potentially invasive plant species along the Garden Route, South Africa, Koedoe 61, a1515. https://doi.org/10.4102/koedoe.v61i1.1515 • Bacher, S., Blackburn, T.M., Essl, F. et al. 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