“One hundred worst” lists of alien species of the greatest concern proved useful for raising awareness of the risks and impacts of biological invasions amongst the general public, politicians and ...stakeholders. All lists so far have been based on expert opinion and primarily aimed at representativeness of the taxonomic and habitat diversity rather than at quantifying the harm the alien species cause. We used the generic impact scoring system (GISS) to rank 486 alien species established in Europe from a wide range of taxonomic groups to identify those with the highest environmental and socioeconomic impact. GISS assigns 12 categories of impact, each quantified on a scale from 0 (no impact detectable) to 5 (the highest impact possible). We ranked species by their total sum of scores and by the number of the highest impact scores. We also compared the listing based on GISS with other expert-based lists of the “worst” invaders. We propose a list of 149 alien species, comprising 54 plants, 49 invertebrates, 40 vertebrates and 6 fungi. Among the highest ranking species are one bird (
Branta canadensis
), four mammals (
Rattus norvegicus, Ondatra zibethicus, Cervus nippon, Muntiacus reevesi
), one crayfish (
Procambarus clarkii
), one mite (
Varroa destructor
), and four plants (
Acacia dealbata, Lantana camara, Pueraria lobata, Eichhornia crassipes
). In contrast to other existing expert-based “worst” lists, the GISS-based list given here highlights some alien species with high impacts that are not represented on any other list. The GISS provides an objective and transparent method to aid prioritization of alien species for management according to their impacts, applicable across taxa and habitats. Our ranking can also be used for justifying inclusion on lists such as the alien species of Union concern of the European Commission, and to fulfill Aichi target 9.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Species of the genus
Acacia
have been introduced worldwide and have negative environmental and socio-economic impacts in many introduced regions. This study makes use of environmental and ...socio-economic impact classification schemes for alien taxa (EICAT and SEICAT) to assess the impacts that 33 acacias introduced to South Africa have at a global scale. The aims of this study were: (1) to compare the EICAT impact categories which are based on literature with expert assessments; (2) to determine which environmental and socio-economic mechanisms underlie acacia impacts; and (3) to test if certain habitats experience higher impact magnitudes than others. Most acacias had a massive impact when evaluated by experts, while the impact was mostly major for EICAT. This could be due to the use of different definitions for the impact categories. It might also show that the data available is insufficient or inadequate in showing that such high impacts exist. Competition was found to be the most often recorded mechanism underlying acacia environmental impacts and was one of the mechanisms with the largest impact magnitude. Grassland, shrubland, marine-coastal and forest habitats were found to be impacted by acacias equally as much. Using impact scoring schemes as an evidence-based and transparent approach to determine the impact status of alien species provides a more robust method to aid management prioritisation and risk assessment than expert opinion alone. However, data quality and availability could limit their effectiveness, especially for less well studied species.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Extensive literature is available on the diversity and magnitude of impacts that alien species cause on recipient systems. Alien species may decrease or increase attributes of ecosystems (e.g. total ...biomass or species diversity), thus causing negative and positive environmental impacts. Alien species may also negatively or positively impact attributes linked to local human communities (e.g. the number of people involved in a given activity). Ethical and societal values contribute to define these environmental and socio-economic impacts as deleterious or beneficial. Whilst most of the literature focuses on the deleterious effects of alien taxa, some recognise their beneficial impacts on ecosystems and human activities. Impact assessment frameworks show a similar tendency to evaluate mainly deleterious impacts: only relatively few, and not widely applied, frameworks incorporate the beneficial impacts of alien species. Here, we provide a summary of the frameworks assessing beneficial impacts and briefly discuss why they might have been less frequently cited and applied than frameworks assessing exclusively deleterious impacts. Then, we review arguments that invoke a greater consideration of positive and beneficial impacts caused by alien species across the invasion science literature. We collate and describe arguments from a set of 47 papers, grouping them in two categories (value-free and value-laden), which span from a theoretical, basic science perspective to an applied science perspective. We also provide example cases associated with each argument. We advocate that the development of transparent and evidence-based frameworks assessing positive and beneficial impacts might advance our scientific understanding of impact dynamics and better inform management and prioritisation decisions. We also advise that this development should be achieved by recognising the underlying ethical and societal values of the frameworks and their intrinsic limitations. The evaluation of positive and beneficial impacts through impact assessment frameworks should not be seen as an attempt to outweigh or to discount deleterious impacts of alien taxa but rather as an opportunity to provide additional information for scientists, managers and policymakers.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Aim An increasingly important component of invasive species management involves the formal assessment of risks associated with particular species becoming invasive and causing impact. We evaluated ...recent developments in risk assessment (RA) for alien species, with special emphasis on species-based pre-border assessments for intentional introductions. Our aim was to identify important advances and key challenges. Location Global. Methods A literature review was done to determine which approaches have been developed and fine-tuned over the last two decades, which of these have worked best and which are most widely used. We identified priorities for improving our ability to assess risks. Results The review is divided into sections on various types and foci of RAs: invasion stage, taxon, ecosystem, assessment method and impact type. RAs for plants are the most advanced, with the Australian Weed Risk Assessment (A-WRA) being the most widely applied and tested protocol. Based on the history of the A-WRA, we highlight advances that have been made in assessing risk of alien species for pre-border control and identify remaining challenges. Main conclusions Currently available RAs have proven to be cost-effective, but there is room for substantial improvement. Further work is needed to separate likelihood and consequence more explicitly, and provide better and more objective means for assessing risks of impact. Types and levels of uncertainty need to be more effectively incorporated. Advanced RA protocols are needed for taxa other than plants and vertebrates. The latest insights from research in invasion ecology need to be incorporated, and advances in other fields must also be taken into account.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NMLJ, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
Alien gastropods have caused extensive harm to biodiversity and socioeconomic systems like agriculture and horticulture worldwide. For conservation and management purposes, information on impacts ...needs to be easily interpretable and comparable, and the factors that determine impacts understood. This study aimed to assess gastropods alien to South Africa to compare impact severity between species and understand how they vary between habitats and mechanisms. Furthermore, we explore the relationship between environmental and socioeconomic impacts, and both impact measures with life‐history traits. We used the Environmental Impact Classification for Alien Taxa (EICAT) and Socio‐Economic Impact Classification for Alien Taxa (SEICAT) to assess impacts of 34 gastropods alien to South Africa including evidence of impact from their entire alien range. We tested for correlations between environmental and socioeconomic impacts per species, and with fecundity and native latitude range using Kendall's tau tests. Kruskal–Wallis tests were used to compare impact magnitude among mechanisms and habitats, respectively. This study presents the first application of EICAT and SEICAT for invertebrates. There was no correlation between environmental impacts and socioeconomic impacts. Habitats did not differ regarding the severity of impacts recorded, but impacts via disease transmission were lower than other mechanisms. Neither fecundity nor native range latitude was correlated with impact magnitude. Despite gastropods being agricultural and horticultural pests globally, resilience of socioeconomic systems makes high impacts uncommon. Environmental systems may be vulnerable to gastropod impacts across habitats, having experienced multiple local extinctions of wetland island snail fauna. South Africa stands out as the only continental country that follows this trend. The knowledge gained on severity and nature of gastropod impacts is useful in risk assessment, which can aid conservation management. To make impact assessments more realistic, we suggest alternative ways of reporting impacts classified under EICAT and SEICAT.
This study assesses global impacts of alien gastropods using two novel impact scoring schemes to compare impact severity between species, as well as environmental and socioeconomic impacts, and to understand how impacts relate to habitats, impact mechanisms, and life‐history traits. The gastropods were found to cause severe impacts in environmental systems across a wide range of habitats and relatively low socioeconomic impacts due to the high resilience of socioeconomic systems. The knowledge gained on the severity and frequency as well as the nature and context dependency of gastropod impacts is useful in risk assessment, which can aid conservation management.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Species moved by human activities beyond the limits of their native geographic ranges into areas in which they do not naturally occur (termed aliens) can cause a broad range of significant changes to ...recipient ecosystems; however, their impacts vary greatly across species and the ecosystems into which they are introduced. There is therefore a critical need for a standardised method to evaluate, compare, and eventually predict the magnitudes of these different impacts. Here, we propose a straightforward system for classifying alien species according to the magnitude of their environmental impacts, based on the mechanisms of impact used to code species in the International Union for Conservation of Nature (IUCN) Global Invasive Species Database, which are presented here for the first time. The classification system uses five semi-quantitative scenarios describing impacts under each mechanism to assign species to different levels of impact-ranging from Minimal to Massive-with assignment corresponding to the highest level of deleterious impact associated with any of the mechanisms. The scheme also includes categories for species that are Not Evaluated, have No Alien Population, or are Data Deficient, and a method for assigning uncertainty to all the classifications. We show how this classification system is applicable at different levels of ecological complexity and different spatial and temporal scales, and embraces existing impact metrics. In fact, the scheme is analogous to the already widely adopted and accepted Red List approach to categorising extinction risk, and so could conceivably be readily integrated with existing practices and policies in many regions.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Defining the Impact of Non‐Native Species JESCHKE, JONATHAN M; BACHER, SVEN; BLACKBURN, TIM M ...
Conservation biology,
October 2014, Volume:
28, Issue:
5
Journal Article
Peer reviewed
Open access
Non‐native species cause changes in the ecosystems to which they are introduced. These changes, or some of them, are usually termed impacts; they can be manifold and potentially damaging to ...ecosystems and biodiversity. However, the impacts of most non‐native species are poorly understood, and a synthesis of available information is being hindered because authors often do not clearly define impact. We argue that explicitly defining the impact of non‐native species will promote progress toward a better understanding of the implications of changes to biodiversity and ecosystems caused by non‐native species; help disentangle which aspects of scientific debates about non‐native species are due to disparate definitions and which represent true scientific discord; and improve communication between scientists from different research disciplines and between scientists, managers, and policy makers. For these reasons and based on examples from the literature, we devised seven key questions that fall into 4 categories: directionality, classification and measurement, ecological or socio‐economic changes, and scale. These questions should help in formulating clear and practical definitions of impact to suit specific scientific, stakeholder, or legislative contexts.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
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.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Human livelihoods and well-being in almost all regions of the world depend on taxa which are alien. Such taxa also, however, threaten human health, sustainable development, and biodiversity. Since it ...is not feasible or desirable to control all alien taxa, decision-makers increasingly rely on risk analyses to formalise the best available evidence of the threats posed and whether and how they can be managed. There are a variety of schemes available that consider the risks of alien taxa, but we argue a new framework is needed: 1) given major recent developments in international frameworks dealing with biological invasions (including the scoring of impacts); 2) so that decisions can be made consistently across taxa, regions and realms; 3) to explicitly set out uncertainties; and 4) to provide decision-makers with information both on the risks posed and on what can be done to mitigate or prevent impacts. Any such scheme must also be flexible enough to deal with constraints in capacity and information. Here we present a framework to address these points – the Risk Analysis for Alien Taxa (RAAT). It outlines a series of questions related to an alien taxon’s likelihood of invasion, realised and potential impacts, and options for management. The framework provides a structure for collating relevant data from the published literature to support a robust, transparent process to list alien taxa under legislative and regulatory requirements, with the aim that it can be completed by a trained science graduate within a few days. The framework also provides a defensible process for developing recommendations for the management of assessed taxa. We trialled the framework in South Africa and outline the process followed and some of the taxa assessed to date.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
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