The regulation of alien species in South Africa

A key global change challenge is to significantly reduce the risks of alien taxa causing harmful impacts without compromising the rights of citizens. As part of efforts to address this challenge, South Africa promulgated comprehensive regulations and lists of alien taxa in 2014. In this paper, we review how the lists developed, changed over time, and how they have been implemented. As of March 2021, 560 taxa were listed under four broad regulatory categories, and between 2014 and 2020, almost 3000 permits were issued to regulate the continued use of listed taxa. The full lists of regulated taxa, permits issued, and corresponding regulations are available in the Supplementary material. A proposed standardised, transparent, and science-informed process to revise the regulatory lists is also presented – as of 30 April 2024, risk analyses have been developed for 140 taxa using the Risk Analysis for Alien Taxa (RAAT) framework and reviewed by an independent scientific body [the Alien Species Risk Analysis Review Panel (ASRARP)] with input from taxon-specific experts. These recommendations are being considered by an interdepartmental governmental decision-making body established in March 2023 [the Risk Analysis Review Committee (RARC)]. Finally, key issues with the listing of alien taxa in South Africa that remain to be resolved are presented. As South Africa’s regulatory framework continues to develop, the process of listing and regulating alien taxa will, we believe, become more transparent, consistent, and acceptable to stakeholders, and ultimately facilitate efforts to reduce the harmful impacts of alien taxa. Significance: The regulation of alien species is a major part of how South Africa addresses biological invasions. For this process to be effective, relevant stakeholders need to be engaged and involved. This paper outlines how species have been regulated in the past, provides regulatory lists in accessible formats, and analyses how the lists have changed over time. A transparent, science-informed process to update the regulatory lists is presented and progress to date reviewed. This process aims to engage interested and affected parties in efforts to preserve the benefits of alien species while reducing the harmful impacts of invasions. Open data set: https://zenodo.org/records/1080976

Montpellier broom (Genista monspessulana) and Spanish broom (Spartium junceum) in South Africa: An assessment of invasiveness and options for management

AbstractThe legumes (Fabaceae) Genista monspessulana and Spartium junceum are major invaders in several other parts of the world, but not yet so in South Africa. We determine their current distributions in South Africa at different spatial scales, assess population structure (soil seed banks and size at reproduction) evaluate current management activities, and provide recommendations for control (including assessing the feasibility of nation-wide eradication). G. monspessulana occurs at nine localities in three quarter-degree cells, covering a total of 22.7ha. S. junceum is much more widespread, occurring in 33 quarter-degree cells and is frequently cultivated in private gardens. All naturalised or invasive populations are in disturbed areas, mostly along roadsides. Once established, G. monspessulana and S. junceum accumulate large, persistent soil-stored seed banks, ranging in size between 909 and 22,727 (median 1970)seeds/m2 and 0 and 21,364 (median 455)seeds/m2 for the two species respectively. Both species resprout vigorously after cutting and stump herbicide application (60% of G. monspessulana and 43% of S. junceum plants resprouted) which necessitates regular follow-ups. We estimate that over 10years, at a cost of about ZAR 81,000 (1 ZAR=0.114 US$ as on 6 October 2012), G. monspessulana could be extirpated from South Africa. S. junceum is far more widespread and coupled with low effectiveness of control, abundance of seeds and seed longevity, eradication is unfeasible. We recommend that control methods used for S. junceum be improved to prevent resprouting, and that areas are managed to limit the movement of seeds and avoid further spread and establishment. Further studies are required to understand why these two species have failed to replicate the invasiveness shown in other parts of the world

Global environmental and socio-economic impacts of selected alien grasses as a basis for ranking threats to South Africa

Decisions to allocate management resources should be underpinned by estimates of the impacts of biological invasions that are comparable across species and locations. For the same reason, it is important to assess what type of impacts are likely to occur where, and if such patterns can be generalised. In this paper, we aim to understand factors shaping patterns in the type and magnitude of impacts of a subset of alien grasses. We used the Generic Impact Scoring System (GISS) to review and quantify published impact records of 58 grass species that are alien to South Africa and to at least one other biogeographical realm. Based on the GISS scores, we investigated how impact magnitudes varied across habitats, regions and impact mechanisms using multiple regression. We found impact records for 48 species. Cortaderia selloana had the highest overall impact score, although in contrast to five other species (Glyceria maxima, Nassella trichotoma, Phalaris aquatica, Polypogon monspeliensis, and Sorghum halepense) it did not score the highest possible impact score for any specific impact mechanism. Consistent with other studies, we found that the most frequent environmental impact was through competition with native plant species (with 75% of cases). Socio-economic impacts were recorded more often and tended to be greater in magnitude than environmental impacts, with impacts recorded particularly often on agricultural and animal production (57% and 51% of cases respectively). There was variation across different regions and habitats in impact magnitude, but the differences were not statistically significant. In conclusion, alien grasses present in South Africa have caused a wide range of negative impacts across most habitats and regions of the world. Reviewing impacts from around the world has provided important information for the management of alien grasses in South Africa, and, we believe, is an important component of management prioritisation processes in general

Border control for stowaway alien species should be prioritised based on variations in establishment debt

Border control is one of the major approaches used by countries to limit the number of organisms introduced as stowaways. However, it is not feasible to inspect all passengers, cargo and vehicles entering a country, and so efforts need to be prioritised. Here we use South Africa as a case study to assess, based on tourism and trade data and climate matching techniques, the number of stowaway species that might be introduced (‘colonisation pressure’) and the likelihood that once introduced, these organisms will establish (‘likelihood of establishment’). These results were used to explore how the number of species that are likely to establish (‘establishment debt’) varies across donor regions and seasons. A simple theoretical model was then used to compare four strategies for prioritising border control inspections: no prioritisation; based on colonisation pressure; based on likelihood of establishment; and based on both colonisation pressure and likelihood of establishment. Establishment debt was greatest in southern hemisphere spring and autumn when South Africa is climatically similar to northern hemisphere countries with which there are strong, consistent trade and tourism links (i.e. colonisation pressure varied little seasonally, but likelihood of establishment did vary across the seasons). Prioritising inspections based on both colonisation pressure and the likelihood of establishment was clearly the most effective strategy, with this strategy detecting at least 6% more potential invaders than the other strategies. While there are many practical limitations to the implementation of such prioritised inspection strategies, the results highlight the importance of national and regional studies of establishment debt.This work was supported by the South African National Department of Environment Affairs through its funding of the South African National Biodiversity Institute’s Invasive Species Programme. Additional funding was provided by the DST-NRF Centre for Invasion Biology. MR acknowledges funding from the South African Research Chairs Initiative of the Department of Science and Technology and National Research Foundation of South Africa.http://www.elsevier.com/locate/jenvman2017-09-30hb2016Zoology and Entomolog

A proposed protocol for identifying native-alien populations

SUPPLEMENTARY MATERIAL TABLE S1. A total of 44 populations of interest that were not classified as native-alien populations. These taxonomic groups are arranged per class. Classification is per the protocol (Figure 1).It is important for regulators and managers to effectively distinguish native from alien taxa. However, a taxon can have both native and alien populations within the same country as biogeographic and administrative boundaries do not always align. Here we propose a protocol for classifying populations as native, alien, cryptogenic, or native-alien, and describe the evidence required. This protocol comprises of three questions: (1) is the population outside the historic native range of the taxon, (2) is/was natural dispersal from the native range unlikely, and (3) is the taxon native to a part of the administrative region where the population is found. If information on introduction pathways, genetics, and biogeographical barriers is available, we propose an alternative process to answer question 2. The protocol was applied to 176 suspected native-alien populations in South Africa. A total of 132 populations from 77 native taxa were classified as native-alien, 13 as cryptogenic, 13 as alien (native-alien status uncertain), and 18 as native. We believe the protocol provides a transparent and standardised method for categorising native-alien populations and thereby facilitates the appropriate regulation and management of this type of biological invasion.The South African Department of Forestry, Fisheries and the Environment (DFFE).http://www.reabic.net/journals/mbi/Default.aspxhj2024Zoology and EntomologySDG-15:Life on lan

Native-alien populations—an apparent oxymoron that requires specific conservation attention

DATA AVAILABILITY : Data for this study are available on request from the authors.SUPPLEMENTARY MATERIAL 1. FILE S1. Authors: Takalani Nelufule, Mark P. Robertson, John R. U. Wilson, Katelyn T. Faulkner Data type: Methods (docx. file) Explanation note: Methods for the simulation that illustrates that native-alien populations are likely to be closer geographically to their native range than populations introduced from other countries. Copyright notice: This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited. Link: https://doi.org/10.3897/neobiota.74.81671.suppl1SUPPLEMENTARY MATERIAL 2. FILE S2. Authors: Takalani Nelufule, Mark P. Robertson, John R. U. Wilson, Katelyn T. Faulkner Data type: Methods (docx. file) Explanation note: Method for determining whether native-alien populations tend to have a greater number of closely related taxa (congeneric and confamilial species) in their introduced range than alien populations introduced from other countries.. Copyright notice: This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited. Link: https://doi.org/10.3897/neobiota.74.81671.suppl2UPPLEMENTARY MATERIAL 3. FILE S3. Authors: Takalani Nelufule, Mark P. Robertson, John R. U. Wilson, Katelyn T. Faulkner Data type: Methods (docx. file) Explanation note: Method for testing whether native-alien populations are particularly prevalent in large, ecologically diverse countries. Copyright notice: This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited. Link: https://doi.org/10.3897/neobiota.74.81671.suppl3Many countries define nativity at a country-level—taxa are categorised as either alien species or native species. However, there are often substantial within-country biogeographical barriers and so a taxon can be native and alien to different parts of the same country. Here, we use the term ‘native-alien populations’ as a short-hand for populations that result from the human-mediated dispersal of individuals of a species beyond a biogeographical barrier to a point beyond that species’ native range, but that is still within the same political entity as parts of the species’ native range. Based on these criteria, we consider native-alien populations to be biological invasions. However, we argue that, in comparison to other alien populations, native-alien populations: 1) are likely to be closer geographically to their native range; 2) are likely to be phylogenetically and ecologically more similar to native species in their introduced range; and 3) options to control their introduction or manage them will likely be more limited. We argue this means nativealien populations tend to differ from other alien populations in the likelihood of invasion, the types of impacts they have, and in how they can be most effectively managed. We also argue that native-alien populations are similarly a distinct phenomenon from native populations that are increasing in abundance or range extent. And note that native-alien populations are expected to be particularly common in large, ecologically diverse countries with disjunct biomes and ecoregions. Reporting, monitoring, regulating and managing native-alien populations will, we believe, become an increasingly important component of managing global change.The South African Department of Forestry, Fisheries and the Environment (DFFE), TISO Foundation and the University of Pretoria.https://neobiota.pensoft.net/https://neobiota.pensoft.netam2023Zoology and Entomolog

Classifying the introduction pathways of alien species: are we moving in the right direction?

This paper emerged from the workshop on ‘Frameworks used in Invasion Science’ hosted by the DSI-NRF Centre of Excellence for Invasion Biology in Stellenbosch, South Africa, 11–13 November 2019.Alien species are introduced to new regions in many different ways and for different purposes. A number of frameworks have been developed to group such pathways of introduction into discrete categories in order to improve our understanding of biological invasions, provide information for interventions that aim to prevent introductions, enable reporting to national and international organisations and facilitate the prediction of threats. The introduction pathway classification framework proposed by the Convention on Biological Diversity (CBD) as a global standard is comprised of six main categories and 44 sub-categories. However, issues have arisen with its implementation. In this position paper, we outline five desirable properties of an introduction pathway classification framework – it should be compatible (i.e. the level of detail of the categories is similar to that of the available data), actionable (i.e. categories link to specific interventions), general (i.e. categories are applicable across the contexts that are of interest (e.g. taxa, habitats and regions)), equivalent (i.e. categories are equivalent in their level of detail) and distinct (i.e. categories are discrete and easily distinguished) – termed the CAGED properties. The six main categories of the CBD framework have all of the CAGED properties, but the detailed sub-categories have few. Therefore, while the framework has been proposed by the CBD as a global standard and efforts have been made to put it into practice, we argue that there is room for improvement. We conclude by presenting scenarios for how the issues identified could be addressed, noting that a hybrid model might be most appropriate.The South African Department of Forestry, Fisheries and the Environment (DFFtE)http://www.pensoft.net/journals/neobiotaam2021Zoology and Entomolog

The balance of trade in alien species between South Africa and the rest of Africa

BACKGROUND : Alien organisms are not only introduced from one biogeographical region to another but also spread within regions. As South Africa shares land borders with six countries, multiple opportunities exist for the transfer of alien species between South Africa and other African countries; however, the direction and importance of intra-regional spread is unclear. OBJECTIVES : The aim of this study was to gain a greater understanding of the introduction of alien species into Africa and the spread of species between South Africa and other African countries. METHOD : We developed scenarios that describe the routes by which alien species are introduced to and spread within Africa and present case studies for each. Using data from literature sources and databases, the relative importance of each scenario for alien birds and insect pests of eucalypts was determined, and the direction and importance of intra-regional spread was assessed. RESULTS : Alien species from many taxonomic groups have, through various routes, been introduced to and spread within Africa. For birds and eucalypt insect pests, the number of species spreading in the region has recently increased, with South Africa being a major recipient of birds (14 species received and 5 donated) and a major donor of eucalypt insect pests (1 species received and 10 donated). For both groups, many introduced species have not yet spread in the region. CONCLUSION : The intra-regional spread of alien species in Africa represents an important and possibly increasing threat to biosecurity. To address this threat, we propose a framework that details how African countries could cooperate and develop a coordinated response to alien species introductions.This paper was initially delivered at the 43rd Annual Research Symposium on the Management of Biological Invasions in South Africa, Goudini Spa, Western Cape, South Africa on 18-20 May 2016.The South African National Department of Environment Affairs through its funding of the South African National Biodiversity Institute’s Invasive Species Programme, the DST-NRF Centre for Invasion Biology, the South African Research Chairs Initiative of the Department of Science and Technology and National Research Foundation of South Africa.http://abcjournal.org/index.php/ABCam2018Forestry and Agricultural Biotechnology Institute (FABI)Zoology and Entomolog

The threats posed by the pet trade in alien terrestrial invertebrates in South Africa

The pet trade has been a major pathway for the introduction of vertebrate invaders, but little is known about its role in invertebrate invasions. Here we assess the trade in terrestrial invertebrates (excluding spiders) in South Africa and the potential of this trade to result in biological invasions and impacts. Pet stores, websites, and expositions were visited, and a list of the taxa traded was compiled. DNA barcoding was used to determine if the species were correctly identified in the trade. Information on invasion history and impact elsewhere was used to assess the potential for species to become invasive and have impact in South Africa. We found 53 alien terrestrial invertebrate taxa that were traded, although only 36 of these matched a valid species name. Of 11 species tested using DNA barcoding nine were correctly identified. Species accumulation curves were produced, but did not reach an asymptote, suggesting there are many species in the trade that were not recorded. The most common species were used as food for pets, rather than as pets themselves. None of the species were reported to be invasive elsewhere, and few had records of causing negative impacts (the exception being moderate impacts to human health caused by venomous scorpions). Therefore, there is little evidence that the invertebrates traded pose a significant threat to South Africa. However, given uncertainties in which taxa are traded and the lack of data on invasiveness and impact, there might be a significant invasion debt. We recommend continued monitoring and engagement with the industry.The South African Department of Forestry, Fisheries, and the Environment (DFFtE)http://www.elsevier.de/jnc2021-06-01hj2020Zoology and Entomolog