# Taming the terminological tempest in invasion science

Ismael Soto, Paride Balzani, Laís Carneiro, Ross Cuthbert, Rafael Macêdo, Ali Serhan Tarkan, Danish Ahmed, Alok Bang, Karolina Bacela-Spychalska, Sarah Bailey, et al.

► To cite this version:

Ismael Soto, Paride Balzani, Laís Carneiro, Ross Cuthbert, Rafael Macêdo, et al. "Taming the terminological tempest in invasion science". Biological Reviews, 2024, 10.1111/brv.13071. hal-04526694

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# Taming the terminological tempest
## in invasion science

Ismael Soto<fnref n="1" />,*, Paride Balzani<fnref n="1" />†, Laís Carneiro<fnref n="2" />†, Ross N. Cuthbert<fnref n="3" />†,
Rafael Macêdo<fnref n="4" />,<fnref n="5" />†, Ali Serhan Tarkan<fnref n="6" />,<fnref n="7" />,⁸†, Danish A. Ahmed⁹, Alok Bang¹⁰,
Karolina Bacela-Spychalska¹¹, Sarah A. Bailey¹², Thomas Baudry¹³,
Liliana Ballesteros-Mejia¹⁴,¹⁵, Alejandro Bortolus¹⁶, Elizabeta Briski¹⁷, J. Robert Britton<fnref n="6" />,
Miloš Buřič<fnref n="1" />, Morelia Camacho-Cervantes¹⁸, Carlos Cano-Barbacil¹⁹,
Denis Copilaş-Ciocianu²⁰, Neil E. Coughlan²¹, Pierre Courtois²², Zoltán Csabai²³,²⁴,
Tatenda Dalu²⁵, Vanessa De Santis²⁶, James W. E. Dickey¹⁷,²⁷,²⁸, Romina D. Dimarco²⁹,
Jannike Falk-Andersson³⁰, Romina D. Fernandez³¹, Margarita Florencio³²,³³,
Ana Clara S. Franco³⁴, Emili García-Berthou³⁴, Daniela Giannetto<fnref n="6" />,
Milka M. Glavendekic³⁵, Michał Grabowski¹¹, Gustavo Heringer³⁶,³⁷,
Ileana Herrera³⁸,³⁹, Wei Huang⁴⁰, Katie L. Kamelamela⁴¹, Natalia I. Kirichenko⁴²,⁴³,⁴⁴,
Antonín Kouba<fnref n="1" />, Melina Kourantidou⁴⁵,⁴⁶,⁴⁷, Irmak Kurtul<fnref n="7" />,⁴⁸, Gabriel Laufer⁴⁹,
Boris Lipták<fnref n="1" />,⁵⁰, Chunlong Liu⁵¹, Eugenia López-López⁵², Vanessa Lozano⁵³,⁵⁴,
Stefano Mammola⁵⁴,⁵⁵,⁵⁶, Agnese Marchini⁵⁷, Valentyna Meshkova⁵⁸,⁵⁹,
Marco Milardi⁶⁰, Dmitrii L. Musolin⁶¹, Martin A. Nuñez²⁹, Francisco J. Oficialdegui<fnref n="1" />,
Jiří Patoka⁶², Zarah Pattison⁶³,⁶⁴, Daniel Pincheira-Donoso<fnref n="3" />, Marina Piria⁸,⁶⁵,
Anna F. Probert⁶⁶, Jes Jessen Rasmussen⁶⁷, David Renault⁶⁸, Filipe Ribeiro⁶⁹, Gil Rilov⁷⁰,
Tamara B. Robinson⁷¹, Axel E. Sanchez⁷², Evangelina Schwindt⁷³, Josie South⁷⁴,
Peter Stoett⁷⁵, Hugo Verreycken⁷⁶, Lorenzo Vilizzi⁸, Yong-Jian Wang⁷⁷,
Yuya Watari⁷⁸, Priscilla M. Wehi⁷⁹,⁸⁰, András Weiperth⁸¹, Peter Wiberg-Larsen⁸²,
Sercan Yapıci<fnref n="6" />, Baran Yoğurtçuoğlu⁸³, Rafael D. Zenni³⁷, Bella S. Galil⁸⁴,
Jaimie T. A. Dick<fnref n="3" />, James C. Russell⁸⁵, Anthony Ricciardi⁸⁶, Daniel Simberloff⁸⁷,
Corey J. A. Bradshaw⁸⁸,⁸⁹§, and Phillip J. Haubrock<fnref n="1" />,⁹,¹⁹§,<fnref n="1" />

<footnote n="1">¹University of South Bohemia in České Budějovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Centre of Aquaculture and Biodiversity of Hydrocenoses, Žátičí 728/II, 389 25, Vodňany, Czech Republic</footnote>

<footnote n="2">²Laboratory of Ecology and Conservation, Department of Environmental Engineering, Universidade Federal do Paraná, Av. Cel. Francisco H. dos Santos, 100, Curitiba 81530-000, Brazil</footnote>

<footnote n="3">³Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, UK</footnote>

<footnote n="4">⁴Institute of Biology, Freie Universität Berlin, Königin-Luise-Str. 1-3, Berlin 14195, Germany</footnote>

<footnote n="5">⁵Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 310, Berlin 12587, Germany</footnote>

<footnote n="6">⁶Department of Basic Sciences, Faculty of Fisheries, Muğla Stkla Koçman University, Kötekli, Menteşe, Muğla 48000, Turkey</footnote>

<footnote n="7">⁷Department of Life and Environmental Sciences, Faculty of Science and Technology, Bournemouth University, Fern Barrow, Poole, Dorset,
BH12 5BB, UK</footnote>

<footnote>* Authors for correspondence: I. Soto (Tel.: +34 638 100 205; E-mail: isma-sa@hotmail.com), C. J. A. Bradshaw (Tel.: +61 400 697 665; E-mail: corey.bradshaw@flinders.edu.au) and P. J. Haubrock (Tel.: +49 176 631 164 03; E-mail: phillip.haubrock@senckenberg.de).</footnote>

<footnote>†Equal second authors.</footnote>

<footnote>§Equal last authors.</footnote>
⁸Department of Ecology and Vertebrate Zoology, Faculty of Biology and Environmental Protection, University of Lodz, Banacha 12/16, Lodz 90-237, Poland

⁹Center for Applied Mathematics and Bioinformatics, Department of Mathematics and Natural Sciences, Gulf University for Science and Technology, Mubarak Al-Abdullaj Area, Hawally 32093, Kuwait

¹⁰Biology Group, School of Arts and Sciences, Azim Premji University, Bhopal, Madhya Pradesh 462010, India

¹¹Department of Invertebrate Zoology and Hydrobiology, Faculty of Biology and Environmental Protection, University of Lodz, Banacha 12/16, Łódź 90-237, Poland

¹²Great Lakes Laboratory for Fisheries and Aquatic Sciences, Fisheries and Oceans Canada, 867 Lakeshore Rd, Burlington, Ontario ON L7S 1A1, Canada

¹³Université de Poitiers, Laboratoire Ecologie et Biologie des Interaction, UMR, CNRS 7267 Équipe Écologie Évolution Symbiose, 3 rue Jacques Fort, Poitiers, Cedex 86000, France

¹⁴Institut de Systématique, Évolution, Biodiversité, Muséum National d'Histoire Naturelle, Centre national de la recherche scientifique, École Pratique des Hautes Études, Sorbonne Université, Université des Antilles, 45 Rue Buffon, Entomologie, Paris 75005, France

¹⁵Centre for Biodiversity Genomics, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada

¹⁶Grupo de Ecología en Ambientes Costeros. Instituto Patagónico para el Estudio de los Ecosistemas Continentales Consejo Nacional de Investigaciones Científicas y Técnicas – Centro Nacional Patagónico, Boulevard Brown 2915, Puerto Madryn, Chubut U9120ACD, Argentina

¹⁷GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, Wischhofstraße 1-3, Kiel 24148, Germany

¹⁸Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México (UNAM), Ciudad Universitaria, Coyoacan, Mexico City 04510, Mexico

¹⁹Department of River Ecology and Conservation, Senckenberg Research Institute and Natural History Museum Frankfurt, Clamecystraße 12, Gelnhausen 63571, Germany

²⁰Laboratory of Evolutionary Ecology of Hydrobionts, Nature Research Centre, Akademijos 2, Vilnius 08412, Lithuania

²¹School of Biological, Earth and Environmental Sciences, University College Cork, Cork T23 TK30, Republic of Ireland

²²Centre d'Économie de l'Environnement - Montpellier, Université de Montpellier, Centre national de la recherche scientifique, Institut national de recherche pour l'agriculture, l'alimentation et l'environnement, Institut Agro, Avenue Agropolis, Montpellier 34090, France

²³University of Pécs, Department of Hydrobiology, Ifjúság 6, Pécs H-7673, Hungary

²⁴HUN-REN Balaton Limnological Research Institute, Klebelsberg Kuno 3, Tihany H-8237, Hungary

²⁵Aquatic Systems Research Group, School of Biology and Environmental Sciences, University of Mpumalanga, Cnr R40 and D725 Roads, Nelspruit 1200, South Africa

²⁶Water Research Institute-National Research Council, Largo Tonolli 50, Verbania-Pallanza 28922, Italy

²⁷Leibniz Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, 12587, Berlin, Germany

²⁸Freie Universität Berlin, Institute of Biology, Königin-Luise-Straße 1-3, Berlin 14195, Germany

²⁹Department of Biology and Biochemistry, University of Houston, Science & Research Building 2, 3455 Cullen Blvd, Houston, TX 77204-5001, USA

³⁰Norwegian Institute for Water Research, Økernveien 94, Oslo 0579, Norway

³¹Instituto de Ecología Regional, Universidad Nacional de Tucumán-Consejo Nacional de Investigaciones Científicas y Técnicas, CC34, 4107, Yerba Buena, Tucumán, Argentina

³²Departamento de Ecología, Facultad de Ciencias, Universidad Autónoma de Madrid, Edificio de Biología, Darwin, 2, 28049, Universidad Autónoma de Madrid, Madrid, Spain

³³Centro de Investigación en Biodiversidad y Cambio Global, 28049, Universidad Autónoma de Madrid, Madrid, Spain

³⁴GRECO, Institute of Aquatic Ecology, University of Girona, Maria Aurèlia Capmany 69, Girona, Catalonia 17003, Spain

³⁵Department of Landscape Architecture and Horticulture, University of Belgrade-Faculty of Forestry, Belgrade, Serbia

³⁶Hochschule für Wirtschaft und Umwelt Nürtingen-Geislingen (HfWU), Schelmenwasen 4-8, Nürtingen 72622, Germany

³⁷Departamento de Ecologia e Conservação, Instituto de Ciências Naturais, Universidade Federal de Lavras (UFLA), Lavras 37203-202, Brazil

³⁸Escuela de Ciencias Ambientales, Universidad Espíritu Santo, Km 2.5 Vía La Puntilla, Samborondón 091650, Ecuador

³⁹Instituto Nacional de Biodiversidad, Casilla Postal 17-07-8982, Quito 170501, Ecuador

⁴⁰Chinese Academy of Sciences Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China

⁴¹School of Ocean Futures, Center for Global Discovery and Conservation Science, Arizona State University, Hilo, HI 96720, USA

⁴²Sukachev Institute of Forest, Siberian Branch of the Russian Academy of Sciences, Federal Research Centre 'Krasnoyarsk Science Centre SB RAS', Akademgorodok 50/28, Krasnoyarsk 660036, Russia

⁴³Siberian Federal University, Institute of Ecology and Geography, 79 Svobodny pr, Krasnoyarsk 660041, Russia

⁴⁴Saint Petersburg State Forest Technical University, Institutski Per. 5, Saint Petersburg 194021, Russia

⁴⁵Department of Business and Sustainability, University of Southern Denmark, Degnevej 14, Esbjerg 6705, Denmark
<footnote n="46">⁴⁶AMURE-Aménagement des Usages des Ressources et des Espaces marins et littoraux, UMR 6308, Université de Bretagne Occidentale, IUEM- Institut Universitaire Européen de la Mer, rue Dumont d'Urville, Plouzané 29280, France</footnote>

<footnote n="47">⁴⁷Marine Policy Center, Woods Hole Oceanographic Institution, 266 Woods Hole Road, Woods Hole, MA 02543, USA</footnote>

<footnote n="48">⁴⁸Marine and Inland Waters Sciences and Technology Department, Faculty of Fisheries, Ege University, Bornova, İzmir 35100, Turkey</footnote>

<footnote n="49">⁴⁹Área Biodiversidad y Conservación, Museo Nacional de Historia Natural, Miguelete 1825, Montevideo 11800, Uruguay</footnote>

<footnote n="50">⁵⁰Slovak Environment Agency, Tajovského 28, Banská Bystrica 975 90, Slovak Republic</footnote>

<footnote n="51">⁵¹The Key Laboratory of Mariculture, Ministry of Education, College of Fisheries, Ocean University of China, 5 Yushan Road, Qingdao 266005, China</footnote>

<footnote n="52">⁵²Instituto Politécnico Nacional, Escuela Nacional de Ciencias Biológicas, Prolongación de Carpio y Plan de Ayala s/n, Col. Santo Tomás, C.P. 11340, Ciudad de México 11340, Mexico</footnote>

<footnote n="53">⁵³Department of Agricultural Sciences, University of Sassari, Viale Italia 39/A, Sassari 07100, Italy</footnote>

<footnote n="54">⁵⁴National Biodiversity Future Centre, Piazza Marina, 61, Palermo 90133, Italy</footnote>

<footnote n="55">⁵⁵Molecular Ecology Group, Water Research Institute, National Research Council, Corso Tonolli 50, Pallanza 28922, Italy</footnote>

<footnote n="56">⁵⁶Finnish Museum of Natural History, University of Helsinki, Pohjoinen Rautatiekatu 13, Helsinki 00100, Finland</footnote>

<footnote n="57">⁵⁷Department of Earth and Environmental Sciences, University of Pavia, Via S. Epifanio 14, Pavia 27100, Italy</footnote>

<footnote n="58">⁵⁸Department of Entomology, Phytopathology, and Physiology, Ukrainian Research Institute of Forestry and Forest Melioration, Pushkinska 86, Kharkiv UA-61024, Ukraine</footnote>

<footnote n="59">⁵⁹Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Kamýcká 1283, Suchdol, Prague 16500, Czech Republic</footnote>

<footnote n="60">⁶⁰Southern Indian Ocean Fisheries Agreement (SIOFA), 13 Rue de Marseille, Le Port, La Réunion 97420, France</footnote>

<footnote n="61">⁶¹European and Mediterranean Plant Protection Organization, 21 bd Richard Lenoir, Paris 75011, France</footnote>

<footnote n="62">⁶²Department of Zoology and Fisheries, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Kamýcká 129, Suchdol, Prague 16500, Czech Republic</footnote>

<footnote n="63">⁶³Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, UK</footnote>

<footnote n="64">⁶⁴Modelling, Evidence and Policy Group, School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK</footnote>

<footnote n="65">⁶⁵University of Zagreb Faculty of Agriculture, Department of Fisheries, Apiculture, Wildlife management and Special Zoology, Svetošimunska cesta 25, Zagreb 10000, Croatia</footnote>

<footnote n="66">⁶⁶Zoology Discipline, School of Environmental and Rural Science, University of New England, Armidale, New South Wales 2351, Australia</footnote>

<footnote n="67">⁶⁷Norwegian Institute for Water Research, Njalsgade 76, Copenhagen S 2300, Denmark</footnote>

<footnote n="68">⁶⁸Université de Rennes, Centre national de la recherche scientifique (CNRS), Écosystèmes, biodiversité, évolution, Rennes 35000, France</footnote>

<footnote n="69">⁶⁹Marine and Environmental Sciences Centre / Aquatic Research Network, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, Lisboa 1749-016, Portugal</footnote>

<footnote n="70">⁷⁰National Institute of Oceanography, Israel Oceanographic and Limnological Research, P.O. Box 8030, Haifa 31080, Israel</footnote>

<footnote n="71">⁷¹Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa</footnote>

<footnote n="72">⁷²Posgrado en Hidrociencias, Colegio de Postgraduados, Carretera México-Texcoco 36.5 km, Montecillo, Texcoco C.P. 56264, Mexico</footnote>

<footnote n="73">⁷³Grupo de Ecología en Ambientes Costeros, Instituto de Biología de Organismos Marinos, Consejo Nacional de Investigaciones Científicas y Técnicas, Boulevard Brown 2915, Puerto Madryn U9120ACD, Argentina</footnote>

<footnote n="74">⁷⁴Water@Leeds, School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK</footnote>

<footnote n="75">⁷⁵Ontario Tech University, 2000 Simcoe St N, Oshawa, Ontario L1G 0C5, Canada</footnote>

<footnote n="76">⁷⁶Research Institute for Nature and Forest, Havenlaan 88 Box 73, Brussels 1000, Belgium</footnote>

<footnote n="77">⁷⁷College of Horticulture and Forestry Sciences, Huazhong Agricultural University, F9F4+6FV, Dangui Rd, Hongshan, Wuhan 430070, China</footnote>

<footnote n="78">⁷⁸Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan</footnote>

<footnote n="79">⁷⁹Te Pūnaha Matatini National Centre of Research Excellence in Complex Systems, University of Auckland, Private Bag 29019, Aotearoa, Auckland 1142, New Zealand</footnote>

<footnote n="80">⁸⁰Centre for Sustainability, University of Otago, 563 Castle Street North, Dunedin North, Aotearoa, Dunedin 9016, New Zealand</footnote>

<footnote n="81">⁸¹Department of Systematic Zoology and Ecology, Institute of Biology, ELTE Eötvös Loránd University, Pázmány Péter Ave 1/C, Budapest H-1117, Hungary</footnote>

<footnote n="82">⁸²Department of Ecoscience, Aarhus University, C.F. Mollers Allé 4-8, Aarhus 8000, Denmark</footnote>

<footnote n="83">⁸³Department of Biology, Faculty of Science, Hacettepe University, Beytepe Campus, Ankara 06800, Turkey</footnote>

<footnote n="84">⁸⁴Steinhardt Museum of Natural History, Tel Aviv University, Klaunserstr. 12, Tel Aviv, Israel</footnote>

<footnote n="85">⁸⁵School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand</footnote>

<footnote n="86">⁸⁶Redpath Museum and Bieler School of Environment, McGill University, 859 Sherbrooke Street West, Montréal, Quebec, Quebec H3A 0C4, Canada</footnote>

<footnote n="87">⁸⁷Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN 37996, USA</footnote>

<footnote n="88">⁸⁸Global Ecology, Partuyarta Ngadluku Wardli Kuu, College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide 5001, South Australia, Australia</footnote>
<sup>89</sup>Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, Wollongong, New South Wales, Australia

ABSTRACT

Standardised terminology in science is important for clarity of interpretation and communication. In invasion science – a dynamic and rapidly evolving discipline – the proliferation of technical terminology has lacked a standardised framework for its development. The result is a convoluted and inconsistent usage of terminology, with various discrepancies in descriptions of damage and interventions. A standardised framework is therefore needed for a clear, universally applicable, and consistent terminology to promote more effective communication across researchers, stakeholders, and policymakers. Inconsistencies in terminology stem from the exponential increase in scientific publications on the patterns and processes of biological invasions authored by experts from various disciplines and countries since the 1990s, as well as publications by legislators and policymakers focusing on practical applications, regulations, and management of resources. Aligning and standardising terminology across stakeholders remains a challenge in invasion science. Here, we review and evaluate the multiple terms used in invasion science (e.g. ‘non-native’, ‘alien’, ‘invasive’ or ‘invader’, ‘exotic’, ‘non-indigenous’, ‘naturalised’, ‘pest’) to propose a more simplified and standardised terminology. The streamlined framework we propose and translate into 28 other languages is based on the terms (i) ‘non-native’, denoting species transported beyond their natural biogeographic range, (ii) ‘established non-native’, i.e. those non-native species that have established self-sustaining populations in their new location(s) in the wild, and (iii) ‘invasive non-native’ – populations of established non-native species that have recently spread or are spreading rapidly in their invaded range actively or passively with or without human mediation. We also highlight the importance of conceptualising ‘spread’ for classifying invasiveness and ‘impact’ for management. Finally, we propose a protocol for classifying populations based on (i) dispersal mechanism, (ii) species origin, (iii) population status, and (iv) impact. Collectively and without introducing new terminology, the framework that we present aims to facilitate effective communication and collaboration in invasion science and management of non-native species.

Key words: biological invasion, classification, communication, non-English language, non-native, polysemy, synonymy.

CONTENTS

<table><tr><td>I. Introduction</td><td>4</td></tr><tr><td>II. Terminological expansion</td><td>6</td></tr><tr><td>(1) Scale mismatches</td><td>7</td></tr><tr><td>(2) Lack of consensus</td><td>8</td></tr><tr><td>III. Terminological tempest</td><td>8</td></tr><tr><td>(1) Previous attempts to tame the ‘terminological tempest’</td><td>15</td></tr><tr><td>(2) Language as a source of ambiguity</td><td>17</td></tr><tr><td>IV. Separating ideology from terminology</td><td>18</td></tr><tr><td>(1) Avoiding problematic terminology</td><td>18</td></tr><tr><td>(2) Conundrum of nativeness and non-nativeness</td><td>18</td></tr><tr><td>V. Proposal for a simplified terminology</td><td>20</td></tr><tr><td>(1) Conceptualising invasive species and spread</td><td>22</td></tr><tr><td>(2) Conceptualising invader impacts and the importance for management</td><td>23</td></tr><tr><td>VI. Proposed classification protocol</td><td>24</td></tr><tr><td>VII. Conclusions</td><td>26</td></tr><tr><td>VIII. Acknowledgements</td><td>26</td></tr><tr><td>IX. Data accessibility</td><td>27</td></tr><tr><td>X. References</td><td>27</td></tr><tr><td>XI. Supporting information</td><td>34</td></tr></table>

I. INTRODUCTION

Scientific disciplines often grapple with lexical and semantic ambiguities and inconsistencies that can confuse, misinterpret, and create barriers to effective interdisciplinary

collaboration among scientists, as well as hinder engagement with practitioners, policymakers, educators, stakeholders, and society (Metzger & Zare, 1999; Regan, Colyvan & Burgman, 2002). This problem spans many fields, from ecology and taxonomy to physics, computer science, and social
science (Boucher, 1985; Herrando-Pérez et al., 2012; Stroud et al., 2015; Kirk et al., 2018; Amador-Cruz et al., 2021; Roth et al., 2021; Bortolus & Schwindt, 2022; Macêdo et al., 2023). Over time, each discipline develops a unique technical lexicon (jargon) with the common challenge of establishing a clear, universally accepted terminology that enables accurate communication within its community and with other scientific or public domains (Montgomery, 1989; Hirst, 2003). While Hodges (2008, p. 35) argued that ‘... [u]seful lexical reviews should focus on the development of [ecological] knowledge that is signalled by a wealth of terms and meanings, rather than critiquing the terms employed’, relying on jargon can be detrimental to effective communication, especially among researchers from different backgrounds and disciplines (Orwell, 1968; Plavén-Sigray et al., 2017; Bullock et al., 2019, Martínez & Mammola, 2021). Judicious use of specialised terms permits effective and precise communication of ideas and concepts not available in the common language, but this is best achieved when jargon is unambiguous and agreed by most scientists in a given field (Hirst, 2003).

Invasion science is a swiftly evolving discipline that encompasses a wide range of specialised fields. Despite its relative youth, the jargon of invasion science has many inconsistent definitions that hinder research progress, effective management, alignment with global-change science, and standardised communication (Colautti & MacIsaac, 2004; Ricciardi & Cohen, 2007; Lockwood, Hoopes & Marchetti, 2013). For example, Castro et al. (2023) found that ambiguous terminology in the field of invasion science hampers effective reporting of non-native taxa for regional checklists. Terms associated with the stages and impacts of biological invasions in particular are often polysemous (i.e. many meanings for a word, phrase, or concept), leading to potential misunderstanding and limitations in scientific exchange and conservation practice (Colautti & MacIsaac, 2004), as well as hindering bidirectional translations between English and other languages (Copp et al., 2021).

Biological invasions are generally defined as directed, human-mediated processes whereby organisms are transported and subsequently released by humans either intentionally or unintentionally beyond their native biogeographical boundaries from which they can potentially spread (Simberloff, 2013; Pyšek et al., 2020). We also acknowledge that terms such as ‘invasion’ and ‘native’ can hold separate cultural meanings for stewardship approaches, including some perspectives by Indigenous Peoples (Wehi et al., 2023). To standardise the terminology in this paper and beyond, we first define the ‘native’ (i.e. natural) range of a species as the biogeographical area where its occurrence has been determined solely by natural evolutionary processes, without any direct or indirect human intervention, such as transporting species, altering their boundaries, and/or breaching natural barriers to their dispersal. This definition implies that a species’ ‘non-native’ range is the area where the species is present due to human intervention, whether intentional or unintentional, and where it has not naturally evolved (McNeill, 2003).

This definition remains applicable regardless of the duration of the species' presence in the area or whether it has undergone evolutionary adaptations in response to the novel environment. However, non-native ranges also include human-assisted expansions due to other phenomena like the removal of biogeographic or climatic barriers caused by anthropogenic activities (Essl et al., 2019).

The process of an initial invasion can be conceptualised as a series of stages – for example: (i) non-native species intentionally or unintentionally transported (including those classified as ‘hitchhikers’) to a new area through human activities, or naturally dispersing after a barrier is removed or made permeable through human action; (ii) escape or introduction of individuals from captivity or cultivation into (evolutionarily) novel locations; (iii) establishment of a viable (i.e. self-sustaining) population; and (iv) spread (when individuals of non-native species disperse spatially from the initial release area). While the latter two stages occur with or without direct human assistance, the quality, quantity, and frequency of introductions (i.e. generally termed ‘propagule pressure’) are relevant at all stages (e.g. Lockwood, Cassey & Blackburn, 2005).

In light of the multifaceted and largely negative effects that non-native species introductions can have on both nature (Blackburn et al., 2011; Bellard, Marino & Courchamp, 2022; Rilov, Canning-Clode & Guy-Haim, 2024) and society (Vilà et al., 2010; Bacher et al., 2018; Diagne et al., 2021; Zhang et al., 2022), research on biological invasions lies at the crossroads of natural and social sciences (Vaz et al., 2017; Heger, Jeschke & Kollmann, 2021; Bortolus & Schwindt, 2022). While a species' native range is identified by a historical range (Fig. 1A) that reflects its evolutionary history, dispersal capacity, and biotic and abiotic constraints, historical records (Fig. 1B) have sometimes been used controversially to justify local reintroductions (Fig. 1C, D), as in the example of rewilding (Seddon et al., 2014). Past ecosystems are generally different from those in the present because ecosystems and their components are not static; therefore, even if historical records confirm the past presence of a species, these do not necessarily imply that species reintroductions will restore previous ecological conditions or positively affect contemporary ecological processes, particularly if the individuals being introduced originate from a population that is genetically distinct from the previous historical population (Davis, 2006; Richardson & Pyšek, 2008; Guerisoli et al., 2023). Multi- and interdisciplinarity have allowed the implementation of innovative approaches to understand and manage biological invasions, but they have also introduced many related, and not always synonymous, terms and contrasting conceptualizations (Lockwood et al., 2005). Further complication derives from the growing scientific attention being asynchronous across habitats, phyla, and geographic regions (Puth & Post, 2005; MacIsaac, Tedla & Ricciardi, 2011; Watkins et al., 2021; Carvalho et al., 2023), which has led to the establishment of multiple ‘invasion science’ communities that develop their own standards and often do not interact (Ojaveer et al., 2015;
<figure><img src="image_3.png" /><figcaption>**Fig. 1.** Relationships between the historical range (A), known historical records (B), and the species current distribution in an ecosystem (C), which are used to justify reintroduction attempts using potentially genetically different source populations (D).</figcaption></figure>

Latombe *et al.*, 2019). The resulting mix of terms and contexts (e.g. political, aesthetic, environmental) within and across disciplines has clouded universal comprehension, in turn impeding effective interventions (Padial *et al.*, 2017; Shackleton *et al.*, 2019; Heger *et al.*, 2021).

## II. TERMINOLOGICAL EXPANSION

The rate at which flora and fauna began to be redistributed widely as a consequence of human endeavour (e.g. the migration of Austronesians; during European colonialism and the so-called 'Columbian exchange') has since been fuelled by expanding transportation networks during the age of industrialisation and rapid global change (Crosby, 1986; Amano *et al.*, 2021; Elton, 2020; Lenzner *et al.*, 2022). The ecological effects of these introductions were so evident, pervasive, and manifold that they were noted by naturalists and others, including Indigenous Peoples, as early as the 19th century (De Candolle, 1855; Darwin, 1859; Te Wehi, 1874; Berg, 1877), and more cogently in the first half of the 20th century (Ritchie, 1920; Oliver, 1930; Madsen, 1937; King, 1942; Oosting, 1948; Leopold, 1949). However, following the publication of Charles S. Elton's seminal book *The Ecology of Invasions by Animals and Plants* in 1958, concerns

have emerged about these phenomena (Cadotte, 2006), which Elton (1942) presciently described as 'ecological pandemonium'. For the first time, Elton described invasions as a process distinct from the colonisations that occur during ecological succession and that drove the breakdown of Wallace's biogeographic realms (Elton, 2020). Later, Baker & Stebbins (1965) took a more neutral stance, describing biological invasions as 'probes' into the evolution and the inner workings of nature. Subsequently, invasion science, as with many other modern disciplines, grew out of a variety of older research fields, including agriculture, botany, ecology, entomology, forestry, mycology, human and animal pathology, and zoology, which often worked in isolation (Cadotte, 2006; Lockwood *et al.*, 2013). This rapid growth proceeded without a generalising framework to standardise and manage the proliferation of technical terminology employed in the field to describe similar phenomena. The international Scientific Committee on Problems of the Environment (SCOPE) programme of the 1980s focused on the integration of scientific knowledge in policy and decision-making related to prominent environmental challenges. It then finally initiated modern invasion science and triggered an explosion of publications (Simberloff, 2011), after setting an agenda for the study of biological invasions by posing three main questions: (i) what factors determine whether a species becomes invasive; (ii) what attributes determine if an ecosystem is
resilient or susceptible to invasion; and (iii) how should invasions be managed, given knowledge addressing questions 1 and 2?

The continuous growth of and advances in invasion science are reflected in the increasing number of scientific publications on this topic, with >8000 scientific papers published by 2019 (see Stevenson *et al.*, 2023). This rapid increase partially reflects the extensive impact of biological invasions on various sectors, including the environment, socio-economy, and human well-being. The increasing interdisciplinarity of invasion science, and the diversity of community voices that were previously ignored in conservation science, underline the need to reconsider widely accepted definitions and concepts (Vaz *et al.*, 2017). However, this trend also highlights the need to tighten the connections between invasion and conservation sciences, and between invasion science and policy, that could otherwise weaken over time (Copp *et al.*, 2005; Stevenson *et al.*, 2023).

To address these challenges already highlighted by Carlton (2002), interdisciplinary research is needed to bridge the gaps among fields (Fachinello, Romero & de Castro, 2022), while simultaneously mitigating the proliferation of and reliance on disparate and convoluted terminology (Simberloff et al., 2013). The surging emphasis on frameworks (Wilson et al., 2020), theories, and hypotheses (Jeschke & Heger, 2018) has exposed certain concepts and ideas as potentially outdated and superfluous (Daly et al., 2023) or requiring amendment (Strayer et al., 2017; Soto et al., 2023a), while also identifying innovative paths such as moving beyond the ‘linear’ conceptualization of invasion dynamics (i.e. transport, introduction, establishment, spread; Blackburn et al., 2011). The first of four stages involves the movement of a species from its native range to a new location. This can be intentional, such as through trade or planting, or accidental, such as stowaways in shipping containers. In the second stage, the transported species is released into the new environment. It can be deliberate, such as when a species is introduced for pest control, or unintentional, such as escapees from aquaria, gardens, or ponds. Establishment refers to the successful reproduction and survival of a non-native species such that the new population becomes self-sustaining in its new environment. In the last stage, the established non-native species expands its range within the new environment. Contemporary perspectives acknowledge the many context dependencies mediating invasions and challenge the simplistic view that invasions are isolated occurrences or linear processes, with invasions potentially better understood as part of an ‘adaptive network’. This considers that spread and impact of non-native species are not simply determined by their intrinsic characteristics, but rather shaped by the broader ecological and socio-economic context (Hui & Richardson, 2019).

## (1) Scale mismatches

Researchers focusing on specific aspects of invasion science across different disciplines have tended to favour nuanced

terminology, which has resulted in polyemies evolving independently in each discipline. Another possible reason behind the many definitions that created ambiguity is the mismatch in spatial scale between measurement and inference of impact. Often, a species' impacts are evaluated at a local scale (e.g. within a specific lake or a forest patch), whereas broader large-scale impacts are inferred by extrapolating local-scale measurements of ecological effects and/or invader abundance across regions or even broader spatial scales, thereby ignoring the spatial variation in the type and severity of impacts that is expected to increase with spatial scale (Haubrock et al., 2022; Ahmed et al., 2023; Soto et al., 2023b). Furthermore, designating a species as 'non-native' is commonly reported at the national scale (the typical spatial entity for which regulations are established) depending on the perspective of each jurisdiction, but in reality, nativeness is determined at the biogeographic scale, thereby de-emphasising sub-national or regional differences and biogeographic boundaries. Furthermore, variation in national perspectives or definitions such as invasiveness being defined based on political boundaries, which might not always correspond with ecological or biogeographic realities (e.g. European Union Regulation 1143/2014) (Vilizzi et al., 2022b), can generate inconsistent terminology among European countries (Haubrock et al., 2024). This is because distributions of non-native species frequently span many countries, while other species can be native to one part of a country and non-native to another (Baquero et al., 2023; Nelufule et al., 2023), exhibiting negative impacts only in the introduced parts of its range (Carey et al., 2012). This can lead to regional variation in approaches, terminology, and priorities within the same country (Vitule et al., 2019). One example is the pirarucu *Arapaima gigas* in Brazil, native to the Lower River Madeira basin in the Amazon. This species has been translocated to adjacent basins where it is not found naturally, resulting in detrimental effects on native species. While *A. gigas* is legally protected and threatened in its native range, the focus of local governments on farming this species generates a demand for more introductions into other basins (Doria et al., 2021).

Another profound example is the hundreds of non-native species crossing from the Red Sea to the Mediterranean Sea directly through the Suez Canal (Galil, 2006; Zenetos et al., 2012; Galil et al., 2021). In Israel, such species can be protected by law along the Red Sea coast, while they can be highly invasive in Mediterranean coastal ecosystems; e.g. rabittfish (*Siganus rivulatus* and *S. luridus*) or the lionfish *Pterois miles* (Sala et al., 2011; Yeruham et al., 2019; Stern et al., 2018; Ulman et al., 2020). These species might therefore require different legislative approaches, like targeted fishing in marine protected areas. The introduction of such species within specific regions or countries has posed challenges in measuring the extent of a species' native range (Pereyra, 2020).

The inconsistent use of terminology has also led to some native species being wrongly designated as 'non-native' (Valéry et al., 2009). This issue is amplified in large countries such as Russia, Canada, China, Australia, South Africa, and
Brazil, which have a diversity of biomes, basins and ecoregions, illustrating the complexity and nuances of species distribution within diverse environments (Yan et al., 2001; Spear & Chown, 2009; Maslyakov & Izhevsky, 2011; Dgebuadze, 2014; Ellender & Weyl, 2014; Nelufule et al., 2022). Furthermore, in countries spanning more than one biogeographical region, species can be both native in one part and non-native in another (e.g. largemouth bass *Micropterus salmoides* in Mexico; Wang et al., 2019). In countries with both continental and insular regions the problem can be exacerbated, such as for some non-native species in Galápagos Islands native to continental Ecuador (e.g. Urquía et al., 2019), or others in Robinson Crusoe Island native to continental Chile (Correa et al., 2008).

The perceived status of a species can also shift from ‘native’ to ‘non-native’, requiring risk evaluation relative to other, already assessed non-native species [e.g. the disputed status of crucian carp *Carassius carassius* in Great Britain (Clavero et al., 2016; Vilizzi et al., 2022a)]. Because the relative abundance of a non-native species within a community is often used to classify its degree of invasiveness (Catford et al., 2016; Haubrock et al., 2022), it can be difficult to separate species expanding their range from those that do not spread without considering the area of reference. Locally established populations of non-native species can exhibit invasive characteristics (i.e. through observed spread, a rapid increase in relative abundance, and/or impacts) in one location, but not in another due to differences in *inter alia* source populations, residence time, habitat invasibility, and environmental (including climatic) conditions of the newly occupied area (Schaffner, 2005).

From a legislative perspective, applying a uniform definition and management approach based solely on national boundaries overlooks the diverse ecological and social contexts, and potential impacts, that might exist within different regions of the same country (Matsuzaki, Sasaki & Akasaka, 2013; Weyl et al., 2016; Sommerwerk et al., 2017). Therefore, spatially explicit information on distribution and status within a biogeographic region and understanding socioeconomic and cultural contexts and values are important for effective management. However, policy and management strategies are generally framed within specific organisational scopes, such as at the country scale. In many cases, even categorising a species as ‘native’ or ‘non-native’ itself at such scales shapes perception and subsequent actions, but there are exceptions. For example, the European Union Regulation on Invasive Alien Species 1143/2014 takes into account three spatial scales: European (i.e. encompassing all Member States), regional, and national. This multi-scale approach allows for a more nuanced consideration of species categorisation and corresponding policies within the European Union.

## (2) Lack of consensus

Despite more than four decades of modern invasion science and the recognised need for a consistent approach, there is

still a lack of consensus over the meaning and usefulness of the terminologies currently in use (Colautti & MacIsaac, 2004; Valéry et al., 2008; Shackleton et al., 2022). The lack of a clear terminology has been exploited in ongoing criticism from those who aim to undermine the value and fundamental goals of invasion science (see Richardson & Ricciardi, 2013), which has further impeded clear communication of the issues associated with biological invasions. In turn, ambiguity can (i) reduce people's understanding and willingness to support actions to avoid or manage biological invasions (e.g. Dunn et al., 2018; Cerri et al., 2020), (ii) be used for ideological or political manipulation of controversial topics arising from non-native species, (iii) shift liability and responsibility for management away from certain stakeholders or even nations that are otherwise bound to prevent and eliminate biological invasions based on prior commitments (e.g. parties to the Convention on Biological Diversity, CBD.int), and ultimately (iv) hinder control and management in ways that increase risks of higher costs or even irreversible damage (Ahmed et al., 2022).

Our aims herein are to (i) review regularly used terms in invasion science and to break down the core definitions of the relevant terminology to identify any associated ideological interpretation; (ii) explore recently proposed approaches by the Darwin Core terms ['degree of establishment' (http://rs.tdwg.org/dwcdoe/values) and 'means' (http://dwc.tdwg.org/em); see Groom et al., 2019], the Convention on Biological Diversity, and by Blackburn et al. (2011) to identify their strengths and commonalities; (iii) propose a simplified terminology to collapse synonymies to produce a harmonised set of terms for standardisation; and (iv) propose an objective classification protocol for non-native species considering four components: (i) dispersal mechanism, (ii) origin, (iii) status, and (iv) impact. Building on the extensive knowledge gained from previous research and tackling the entanglement of the ongoing discussion, our review attempts to mitigate these concerns by suggesting a consolidated, streamlined, and comprehensive terminology. This framework aims to clarify the lexicon of invasion science. While striving for a consensus definition is beneficial, we concede that it might not always be attainable, particularly when dealing with pluralism and complex concepts like biodiversity, species, and life (Pascual et al., 2021). We therefore acknowledge that even among ourselves, there remains disagreement about how some terms should be defined, reflecting the diversity of opinions within our evolving field and demonstrating the importance of international and multidisciplinary discussions on how to clarify terminology.

## III. TERMINOLOGICAL TEMPEST

The language of invasion science is a complex network of terms that are often used interchangeably, yet each of these terms carries specific implications for understanding the nature, origins, and impacts of the organisms. The meaning
of these terms can also vary among scholars in various disciplines, by culture and education, and among policy-makers and the public (see Ricciardi & Cohen, 2007). In August 2023, we did a comprehensive search of the literature to identify relevant terms used to describe ‘non-native’ species (Table 1). We initially reviewed Colautti & MacIsaac (2004), Falk-Petersen, Böhn & Sandlund (2006), and Lockwood et al. (2013), which we subsequently expanded with suggestions by co-authors and checked the resulting terms in the *Web of Science* for relevance.

We identified a total of 59 terms used to describe or classify non-native species, which exceeds those identified by Colautti & MacIsaac (2004), Falk-Petersen et al. (2006), and Lockwood et al. (2013) more than a decade ago (they identified 25, 30, and 27 terms, respectively). Based on a comprehensive scoping review, employing platforms such as *Web of Science* and *Google Scholar*, as well as opportunistic searches to explore both scientific and grey literature, we then counted the number of papers that employed those 59 terms based on the specific search for each term (e.g. ‘invasive’ species; Table 1), while excluding unrelated fields such as medicine or psychology. We focused on literature published in English, but with the exponential growth in the number of potentially relevant papers in non-English languages (Chowdhury et al., 2023), we assume a similar boom in terminology also could be expected in many other languages. We recognise that integrating literature from other languages enriches many scientific disciplines (Angulo et al., 2021; Zenni et al., 2023); however, it could also introduce socio-political complexities that are not central to our primary objective – a concise terminology in invasion science. As non-English languages gain prominence in scientific discourse, the need to propose unified terminologies becomes even more pressing to ensure a global consensus on knowledge and best practice.

Increasing scientific interest resulting in more published articles has introduced more terms to the lexicon (Fig. 2), which seems to be a source of confusion and potential driving force of ambiguity in identifying non-native species, prioritising management, determining appropriate control measures, and allocating resources adequately and effectively (Ricciardi & Cohen, 2007; Lockwood et al., 2013; Iannone III et al., 2020). This issue is compounded by the use of acronyms and initialisms for terminology. An example is the initialism IAS used by some for ‘invasive alien species’, whereas others have used it to mean ‘invasive animal species’ (Carlon & Dominoni, 2023). Similarly, South Africa’s regulations on biological invasions refer to ‘alien and invasive species’, often shortened to AIS and then confused with the narrower grouping of ‘alien invasive species’ (also AIS, a synonym of IAS). Others have preferred the initialism A&IS to resolve this confusion, although yet another initialism still constitutes specialist jargon (Zengeya & Wilson, 2020). The initialism AIS also has been used to indicate ‘aquatic invasive species’ e.g. in the documentations and website of the Great Lakes Commission (Canada, USA; glc.org/work/ais), adding to the terminological confusion. Another example is the use of the term ‘non-indigenous species’ (and initialism NIS) (synonym:

non-native species) in some peer-reviewed papers (Colautti, Grigorovich & MacIsaac, 2006; Colautti & Richardson, 2009; Ojaveer et al., 2015; Riera et al., 2018), while the same abbreviation has been used to indicate a ‘nuisance invasive species’ (Pereyra, Rossini & Darrigran, 2012). Adding to the confusion, initialisms for the same term differ among nations and regions – adapted to their own language – such as the governmental initiatives in Argentina and Brazil called ‘National Strategy on Invasive Exotic Species’ [NSIES, or ENEEI in Portuguese or Spanish (Faria et al., 2022; Schwindt et al., 2022)].

Among the terms we found in the identified literature, the most frequent was ‘invasive’, appearing in 37.1% of the 70,188 publications (Fig. 2), followed by terms such as ‘alien’, ‘non-native’, ‘exotic’, and, *inter alia*, ‘introduced’. However, the relative dominance of terms varied when we used the adjective without ‘species’, albeit painting a comparable picture (see online Supporting Information, Fig. S1). The use of these terms often varied according to the scientific discipline. For example, ‘weed’ is commonly used in botanical studies focusing on plant invasion. By contrast, ‘invasive’ is a more universal term applicable to all taxa, which likely explains its widespread uptake across many disciplines. The term ‘invasive’ itself has a convoluted origin. A terminological shift occurred in the 1990s as ‘invasive’ began replacing terms like ‘introduced’ (sometimes used to refer to those at the arrival stage and/or those established) and ‘non-indigenous’. At a national scale, this shift was deliberately implemented in US legislation, specifically when the *Non-Indigenous Aquatic Nuisance Prevention and Control Act 1990* was renewed in 1995 and renamed the *National Invasive Species Act*. The two main elements influencing this revision were that: (i) the term ‘invasive’ carried a more impactful and compelling implication compared to the milder ‘non-indigenous’ (Carlton, 2002), and (ii) the 1990 act lacked an easily pronounceable acronym, leading to alternative names such as the *Ballast Water Act* or *Zebra Mussel Act*. The definition of ‘invasive’ was further obscured with Executive Order 13112 by U.S. President Bill Clinton in 1999, which specifically included ‘impact’ and ‘economic harm’. ‘Invasive alien species’ is currently used by the European Commission in its regulations (http://environment.ec.europa.eu/topics/nature-and-biodiversity/invasive-alien-species_en), which is also the term most widely used by the Convention on Biological Diversity (in English, but not in other languages), the United Nations Sustainable Development Goals, and International Union for Conservation of Nature (IUCN).

Several papers and book chapters subsequently explored and discussed the term ‘invasive’ (Sax, Stachowicz & Gaines, 2005; Lockwood et al., 2013). In general, terminological pitfalls have been avoided by providing definitions for selected terminology (e.g. Rilov & Crooks, 2009). However, ‘invasive’ is often used without a precise description of its implications, such as the extent of spread observed (for spread-based definitions) or impact caused (for harm-based definitions), which are themselves ambiguous. One type of impact is denoted ‘species replacement’, which has been ambiguously described as ‘displacement’, ‘elimination’, ‘eradication’,
<table><caption>Table 1. Definitions of the English terms most often used in invasion science for classifying species. The terms highlighted in italics and bold in the ‘Definition’ column indicate cases where particular terms are themselves used as definitions. Numbers in parentheses in the first column indicate the number of identified papers for that specific term. ‘Related terms’ refers to synonyms and associated terms.</caption><thead><tr><th>Term</th><th>Definition</th><th>Example references</th><th>Related terms</th></tr></thead><tbody><tr><td>acclimatised (8)</td><td>Presence despite being able to fulfil a portion or most of its life cycle in a <strong>foreign</strong> environment or climate, unable to reproduce or maintain a viable population without human intervention</td><td>Scalera & Zaghi (2004)</td><td>adventive, casual, newcomer, non-resident, transient</td></tr><tr><td>adventive (162)</td><td>In an early stage of <strong>invasion</strong> and not yet spread ‘extensively’ [undefined] beyond the point of introduction</td><td>Morris (1992); Binggeli (1994); Lawrence (2000); Klimaszewski et al. (2013)</td><td>acclimatised, casual, newcomer, non-resident, transient</td></tr><tr><td>alien (8080)</td><td><strong>Introduced</strong> to an area in which it does not occur naturally</td><td>Crawley et al. (1999), Pyšek et al. (2020)</td><td>allochthonous, anthropochore, exotic, foreign, imported, immigrant, introduced, migrant, non-indigenous, non-native, transported, xenobiota</td></tr><tr><td>allochthonous (130)</td><td><strong>Introduced</strong> into a new area outside the native range (in which it is autochthonous)</td><td>Corsini-Foka & Economidis (2007)</td><td>alien, anthropochore, exotic, foreign, imported, immigrant, introduced, migrant, neobiota, non-indigenous, non-native, transported, xenobiota</td></tr><tr><td>anthropochore (96)</td><td>Actively disperses seeds or propagules through direct or indirect human intervention</td><td>James & Hendrix (2004)</td><td>alien, allochthonous, exotic, foreign, imported, immigrant, introduced, migrant, neobiota, non-indigenous, non-native, transported, xenobiota</td></tr><tr><td>archaeophyte (230)</td><td>Plants that became <strong>naturalised</strong> in a specific region or area before 1492 (pre-‘Columbian exchange’)</td><td>La Sorte & Pyšek (2009)</td><td>neophyte</td></tr><tr><td>bioinvader (35)</td><td><strong>Non-native introduced</strong> to new environments that causes ecological and socio-economic damage</td><td>Pérez et al. (2008)</td><td>biopollution, invasive/invader, noxious, nuisance, pest, unwanted, vermin, weed</td></tr><tr><td>biopollution (30)</td><td>Have harmful or disruptive effects on native ecosystems, often due to <strong>invasive</strong> nature or aggressive behaviours</td><td>Occhipinti-Ambrogi (2021)</td><td>bioinvader, invasive/invader, noxious, nuisance, pest, unwanted, vermin, weed</td></tr><tr><td>casual (40)</td><td>Incapable of persisting in a novel environment, despite capacity for reproduction there; persistence depends on regular re-<strong>introductions</strong> to rescue otherwise moribund populations</td><td>Wu et al. (2004)</td><td>acclimatised, adventive, newcomer, non-resident, transient</td></tr><tr><td>coloniser/colonist (5954)</td><td>Capable of <strong>establishing</strong> in a new area, often through a combination of high reproductive rates, efficient dispersal, and adaptive traits enabling it to tolerate or exploit the new environment; individuals in a founding population reproduce, increase in abundance, and form a self-perpetuating population</td><td>Davis & Thompson (2000); Davis (2009)</td><td>established, invasive/invader, naturalised, transformer</td></tr><tr><td>cryptogenic (162)</td><td>When there is uncertainty about the native range, and native/<strong>non-native</strong> status in an area</td><td>Carlton (1996)</td><td>questionable</td></tr><tr><td>domestic (invasive, exotic, alien) (8)</td><td>Introduced to internal units from within the national border</td><td>Guo & Ricklefs (2010); Kamada et al. (2013)</td><td>extralimital, translocated, intra-country established alien</td></tr><tr><td>escaped (9)</td><td>Escaped captivity (e.g. pet stores, aquaculture facilities, herbaria, zoos, garden plants), and <strong>established</strong> populations in the wild</td><td>Padilla & Williams (2004)</td><td>feral, released</td></tr><tr><td>established (817)</td><td>Self-sustaining population(s) in a new area; phenomenon experienced by an</td><td>Keller et al. (2011); Gormley et al. (2011)</td><td>coloniser/colonist, invasive/invader, naturalised, transformer</td></tr></tbody></table>

(Continues on next page)
<table><caption>Table 1. (Cont.)</caption><thead><tr><th>Term</th><th>Definition</th><th>Example references</th><th>Related terms</th></tr></thead><tbody><tr><td>exotic<br>(6883)</td><td><strong>alien</strong> after <strong>introduction</strong> resulting in an independent <strong>established</strong> population in natural habitats<br><strong>Introduced</strong> into a new area outside the native range</td><td>Green (1997); Myers et al. (2000)</td><td>alien, allochthonous, anthropochore, exotic, imported, immigrant, introduced, migrant, neobiota, non-indigenous, non-native, transported, xenobiota</td></tr><tr><td>extralimital<br>(56)</td><td>Native range falls within the political boundaries of a country, but presence in another part of the same country attributable to human transport across biogeographical barriers</td><td>Robinson et al. (2016)</td><td>intra-country established alien, transferred, translocated, tramp, vagrant, waif</td></tr><tr><td>feral<br>(53)</td><td>Organisms or their descendants domesticated, confined (animals) or cultivated (plants) and subsequently released or <strong>escaped</strong> into the natural environment</td><td>Liu & Li (2009)</td><td>escaped, released</td></tr><tr><td>foreign<br>(162)</td><td><strong>Non-native</strong> or <strong>non-indigenous</strong> to a particular region or country; <strong>translocated</strong> beyond its native range to another country across an international boundary</td><td>Richardson & Pyšek (2008)</td><td>alien, allochthonous, anthropochore, exotic, imported, immigrant, introduced, migrant, neobiota, non-indigenous, non-native, transported, xenobiota</td></tr><tr><td>immigrant<br>(64)</td><td>Moved from the native range to a new area where not previously occurring naturally</td><td>De Meester et al. (2007)</td><td>alien, allochthonous, anthropochore, exotic, foreign, imported, introduced, migrant, neobiota, non-indigenous, non-native, transported, xenobiota</td></tr><tr><td>imported<br>(53)</td><td><strong>Translocated</strong> into a new area from the native range</td><td>Holzapfel & Vinebrooke (2005); Williamson & Fitter (1996)</td><td>alien, allochthonous, anthropochore, exotic, foreign, immigrant, introduced, migrant, neobiota, non-indigenous, non-native, transported, xenobiota</td></tr><tr><td>intra-country established alien<br>(1)<br>introduced<br>(5443)</td><td>Successful <strong>introductions</strong> and <strong>establishment</strong> among regions or in a novel region within the same country<br><strong>Translocated</strong> by humans to a new geographic location where did not occur naturally; intentional or unintentional (accidental)<br><strong>introduction</strong> and/or release by humans, either directly or indirectly, into natural or anthropogenically altered (e.g. urban) environments or locations, in geographical areas where (species, subspecies, race, or variety) is not found naturally</td><td>Vitule et al. (2019)</td><td>extralimital, native-alien populations, transferred, translocated, tramp, vagrant, waif</td></tr><tr><td>invader<br>(9978) / invasive<br>(26030)</td><td><strong>Non-natives introduced</strong> to a new environment with ability to spread and cause ecological and socio-economic damage; either native or <strong>alien</strong> that can spread and <strong>establish</strong> in natural or semi-natural habitats, either with or without human assistance; can encompass spread and/or impact</td><td>Simberloff et al. (2005)</td><td>alien, allochthonous, anthropochore, exotic, foreign, imported, immigrant, migrant, neobiota, non-indigenous, non-native, transported, xenobiota</td></tr><tr><td>invasive alien (2402)</td><td>Introduction and/or spread outside natural past or present distribution threatens biological diversity</td><td>Simberloff (2010)</td><td>coloniser/colonist, established, naturalised, transformer</td></tr><tr><td>invasive non-native<br>(242)</td><td><strong>Introduced</strong> by humans (intentionally or accidentally) into areas where does not occur naturally without recognisable negative impact</td><td>CBD (2020); Pyšek et al. (2020)</td><td>invasive non-native, invasive super dominant, neonative, new non-native</td></tr><tr><td>invasive super dominant<br>(1)</td><td>Not only successfully <strong>established</strong> in a new ecosystem, but also becomes</td><td>Vitule et al. (2021); CBD (2020)</td><td>invasive alien, invasive super dominant, neonative, new non-native</td></tr><tr><td></td><td></td><td>Pivello et al. (2018)</td><td>invasive alien, invasive non-native, neonative, new non-native, transformer</td></tr></tbody></table>

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<table><caption>Table 1. (Cont.)</caption><thead><tr><th>Term</th><th>Definition</th><th>Example references</th><th>Related terms</th></tr></thead><tbody><tr><td>migrant<br>(444)</td><td>Moved from its native habitats to new geographic areas; can be natural (e.g. birds migrating between continents), or facilitated by humans</td><td>Ibanez et al. (2008)</td><td>alien, allochthonous, anthropochore, exotic, foreign, imported, immigrant, introduced, neobiota, non-indigenous, non-native, transported, xenobiota</td></tr><tr><td>naturalised<br>(379)</td><td><strong>Non-native</strong> successfully established self-sustaining populations in a new environment without human intervention; non-native after being introduced successfully established self-sustaining populations in the wild; must be present long enough to be perceived as an integral [undefined] part of the resident community of organisms</td><td>Wu et al. (2004)</td><td>coloniser/colonist, established, invasive/invader, transformer</td></tr><tr><td>neobiota<br>(40)</td><td><strong>Introduced</strong> into new habitats or regions, typically due to human activities; can have ecological impacts and include invasives</td><td>Schittko et al. (2020)</td><td>alien, allochthonous, anthropochore, exotic, foreign, imported, immigrant, introduced, migrant, non-indigenous, non-native, transported, xenobiota</td></tr><tr><td>neophyte<br>(766)</td><td><strong>Introduced</strong> to a new habitat or region after 1492; often not fully integrated into new ecosystems and can still be in the process of spreading and establishing</td><td>Kühn et al. (2017)</td><td>archaeophyte</td></tr><tr><td>new non-native<br>(28)</td><td>Fills similar role(s) to an extinct native that is not closely related (no more closely related than order)</td><td>Blackman et al. (2017)</td><td>Invasive alien, invasive non-native, invasive super dominants, neonative</td></tr><tr><td>neonative<br>(5)</td><td>Expanded geographically beyond the native range and established populations driven by human-induced environmental change without human assistance</td><td>Essl et al. (2019, 2021b); Wallingford et al. (2020)</td><td>invasive alien, invasive non-native, new non-native</td></tr><tr><td>newcomer<br>(6)</td><td>Recently established in a particular ecosystem or geographical area, often due to natural or human-mediated introductions</td><td>Evans et al. (2020)</td><td>acclimatized, adventive, casual, non-resident, transient</td></tr><tr><td>non-indigenous<br>(2349)</td><td>Not found naturally in a particular geographic location or ecosystem</td><td>Ojaveer et al. (2015)</td><td>alien, allochthonous, anthropochore, exotic, foreign, imported, immigrant, introduced, migrant, neobiota, non-native, transported, xenobiota</td></tr><tr><td>non-native<br>(5341)</td><td><strong>Introduced</strong> to an area outside of natural range</td><td>Jeschke et al. (2014)</td><td>alien, allochthonous, anthropochore, exotic, foreign, imported, immigrant, introduced, migrant, neobiota, non-indigenous, transported, xenobiota</td></tr><tr><td>non-resident<br>(46)</td><td>No recent evolutionary history in focal ecological network and not familiar with species in that network (cf. 'resident')</td><td>Eckstein et al. (2012); Saul & Jeschke (2015)</td><td>acclimatised, adventive, casual, newcomer, transient</td></tr><tr><td>noxious<br>(65)</td><td>Harmful or dangerous to human health, agriculture, or environment</td><td>Andreu et al. (2009)</td><td>bioinvader, biopollution, invasive/invader, nuisance, pest, unwanted, vermin, weed</td></tr><tr><td>nuisance<br>(256)</td><td>Annoying or inconveniencing humans; typically not harmful or dangerous; can be non-native or native</td><td>Barrett et al. (2019)</td><td>bioinvader, biopollution, invasive/invader, noxious, pest, unwanted, vermin, weed</td></tr><tr><td>pest<br>(2702)</td><td>Harmful or destructive to humans, crops, livestock, or property; can be non-native or native</td><td>Worner & Gevrey (2006)</td><td>bioinvader, biopollution, invasive/invader, noxious, nuisance, unwanted, vermin, weed</td></tr><tr><td>pseudo-indigenous<br>(7)</td><td><strong>Introduced</strong> species mistakenly identified as native</td><td>Carlton (2009)</td><td></td></tr></tbody></table>

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<table><caption>Table 1. (Cont.)</caption><thead><tr><th>Term</th><th>Definition</th><th>Example references</th><th>Related terms</th></tr></thead><tbody><tr><td>questionable (28)</td><td>Status as native or <strong>non-native</strong> (alien/ invasive) uncertain or disputed</td><td>Zenetos et al. (2010)</td><td>cryptogenic</td></tr><tr><td>range- expanding (65)</td><td>Extends geographical distribution beyond previously known or <strong>established</strong> range, often due to climate change, habitat modification, or dispersal abilities</td><td>Essl et al. (2019)</td><td>coloniser/colonist, established, invasive/invader, naturalised, transformer</td></tr><tr><td>released (58)</td><td>Deliberately or accidentally <strong>introduced</strong> into an environment outside of native range by humans</td><td>Blumenthal (2006)</td><td>escaped, feral</td></tr><tr><td>restocked (1)</td><td>Re-introduced or replenished in a specific area through deliberate human intervention, often aimed at restoring or increasing population sizes, not specifically of same species</td><td>Roll et al. (2007)</td><td>transplanted</td></tr><tr><td>tramp (48)</td><td>Ability to colonise and spread rapidly across new habitats, often facilitated by humans; (non-native) disturbance specialist, closely associated with humans</td><td>Passera (2021)</td><td>extralimital, intra-country established alien, transferred, translocated, vagrant, waif</td></tr><tr><td>transferred (80)</td><td>Moved across a national border to a country within natural range</td><td>McGlynn (1999)</td><td>extralimital, intra-country established alien, translocated, tramp, vagrant, waif</td></tr><tr><td>transformer (24)</td><td>Alters the character, condition, form, or nature of an ecosystem over a broad area</td><td>Richardson et al. (2000); Protopopova et al. (2015)</td><td>coloniser/colonist, established, invasive/invader, invasive super dominants, naturalised</td></tr><tr><td>transient (496)</td><td>Occurs in a particular location only temporarily or sporadically</td><td>Snell Taylor et al. (2018)</td><td>acclimatised, adventive, casual, newcomer, non-resident</td></tr><tr><td>translocated (98)</td><td>Moved from the native range to a new location by humans; <strong>intra-country</strong> translocation is <strong>introduction</strong> from one region or political entity (country) within the same country where native to another region and where not found naturally; moved by humans for conservation (e.g. assisted migration/ colonisation); see also <strong>intra-country established alien</strong></td><td>Vitule et al. (2019); Doria et al. (2021); Essl et al. (2021b)</td><td>extralimital, intra-country established alien, transferred, tramp, vagrant, waif</td></tr><tr><td>transplanted (58)</td><td><strong>Introduced</strong> outside the native range, usually for ecological restoration or commerce/recreation; can be either <strong>non-native</strong> or native to area of transplantation</td><td>Hargreaves et al. (2014)</td><td>restocked</td></tr><tr><td>transported (94)</td><td>Moved outside the native range, can be either <strong>non-native</strong> or native to area of transport</td><td>Gross &amp; Pharr (1982)</td><td>alien, allochthonous, anthropochore, exotic, foreign, imported, immigrant, introduced, migrant, neobiota, non-indigenous, non-native, xenobiota</td></tr><tr><td>unwanted (97)</td><td>Undesirable for humans, crops, aquaculture, or property; can be <strong>non-native</strong> or native</td><td>Iuell (2002); Naylor et al. (2001); Caley &amp; Kuhnert (2006); Nagy &amp; Johnson II (2013)</td><td>bioinvader, biopollution, noxious, nuisance, pest, vermin, weed</td></tr><tr><td>vagrant (61)</td><td>Occur outside typical or expected range or habitat, often individual or fine-scale occurrences</td><td>Luiz et al. (2013)</td><td>extralimital, intra-country established alien, transferred, translocated, tramp, waif</td></tr><tr><td>vermin (147)</td><td>Undesirable due to detrimental impacts on agriculture, horticulture, or enemies to game preservation</td><td>Smout (2003)</td><td>bioinvader, biopollution, noxious, nuisance, pest, unwanted, weed</td></tr><tr><td>waif (74)</td><td>Found outside the normal geographic range, usually far from the native</td><td>Christy et al. (2009)</td><td>extralimital, intra-country established alien, transferred, translocated, tramp, vagrant</td></tr></tbody></table>

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<table><caption>Table 1. (Cont.)</caption><thead><tr><th>Term</th><th>Definition</th><th>Example references</th><th>Related terms</th></tr></thead><tbody><tr><td><i>weed</i><br>(6146)</td><td>habitat, often without clear evidence of human-mediated transport<br>Plants considered undesirable or unwanted in a particular setting, typically due to competitive nature, rapid growth, and ability to spread quickly</td><td>Ogg &amp; Dawson (1984)</td><td>bioinvader, biopollution, noxious, nuisance, pest, unwanted, vermin</td></tr><tr><td><i>xenobiota</i> (1)</td><td><b>Introduced</b> or <b>non-native</b> to a particular ecosystem or geographic region, often originating from a different ecosystem or geographic area</td><td>Tsadok et al. (2015)</td><td>alien, allochthonous, anthropochore, exotic, foreign, imported, immigrant, introduced, migrant, neobiota, non-indigenous, non-native, transported</td></tr></tbody></table>

'exclusion', 'extirpation', 'extinction', and 'supplanted'. 'Invasive' can also have several meanings; for example, it can refer to species that have successfully established and spread to new areas, regardless of their impacts (Richardson *et al.*, 2000; Blackburn *et al.*, 2011), or those causing ecological or

socio-economic harm in their new environment regardless of the stage of the invasion process (Leung *et al.*, 2002; Lockwood *et al.*, 2013). 'Invasive' has also been applied to weedy species such as *Phragmites australis* in Europe and Asia, where it is native but can become dominant due to human

<figure><img src="image_4.png" /><figcaption>**Fig. 2.** (A) Total term diversity (i.e. number of different terms used in each particular year) over time, cumulative term diversity, and the instantaneous rate of change of diversity of terms. (B) Count timeline (log₁₀ scale) lines reflecting the trend for each individual term identified in Table 1 (some popular terms are highlighted with colours). Wordcloud (inset) shows the total frequency use of each term (size of text is proportional to the total number of uses – only 40 different terms are shown). All terms here were used as adjectives with 'species' in the search string (e.g. 'invasive species'). Data and R code to reproduce trends and word cloud available from http://github.com/IsmaSA/Invasion-science-terminology.</figcaption></figure>
disturbance (Lambert, Dudley & Saltonstall, 2010). ‘Invasive’ has even been applied to ecologically dominant native species undergoing a demographic explosion (Valéry et al., 2009; Packer et al., 2017), possibly a legacy of early plant scientists using ‘invading’ synonymously with ‘spreading’.

Amid this etymological complexity, the nuanced interpretations of several terms used by invasion scientists to describe species such as ‘invasive’, ‘invader’, ‘introduced’, ‘naturallised’, ‘non-indigenous’, and ‘exotic’ cannot be overlooked. These terms are often used interchangeably, even within a single study (to avoid word repetitions), raising several concerns about their potential misinterpretation and misapplication, including the politicisation of non-native species (Ricciardi & Cohen, 2007; Russell & Blackburn, 2017). Each of these terms can have a unique, nuanced interpretation that relates to a specific aspect of population spread and the perceived negative impacts it can cause (Lockwood et al., 2013). As such, labelling a species ‘invasive’ implies that its populations pose some harm or threat according to some frequently adopted definitions, such as those used by the Convention on Biological Diversity (Leung et al., 2002; Lockwood et al., 2013), but other definitions do not invoke harm or impact in general (Falk-Petersen et al., 2006; Ricciardi & Cohen, 2007). Other terms such as ‘exotic’, ‘alien’, and ‘non-indigenous’ do not inherently imply harm to ecological or socio-economic systems (see also Falk-Petersen et al., 2006; Stoett, 2010; Fachinello et al., 2022).

## (1) Previous attempts to tame the ‘terminological tempest’

Despite multiple attempts to address the complex terminology in invasion science (Table 2), confusion nevertheless persists (Occhipinti-Ambrogi & Galil, 2004; Courchamp et al., 2017; Colautti & Richardson, 2009). This has led to proposed protocols to identify the most appropriate terms for classifying species based on their stage of invasion (Colautti & Richardson, 2009; Colautti et al., 2014). The Convention on Biological Diversity followed a simple and practical approach by defining ‘invasive’ as non-native plants, animals, pathogens, and other organisms that are introduced or that spread outside their natural habitats if they pose a threat to native biodiversity, otherwise cause environmental harm, impose negative economic consequences, or adversely affect human health (CBD, 2020). This definition emphasises measurable, negative impact (itself time-dependent, and might occur without notice or measure) and the potential for spread, with these two phenomena not necessarily linked. However, the ability or potential to spread is, like introduction, often aided by humans. But all established non-native species, because they interact with the local environment, will have some type of ecological effect – positive, negative, or mixed – along a continuum from negligible to enormous (Ricciardi et al., 2013). Indeed, widely cited estimates of the proportion of invasions that have impacts are likely underestimated (Simberloff et al., 2013).

Determining what constitutes an ‘invasive’ species can be difficult because of the demographic dimensions of invasiveness (Colautti & MacIsaac, 2004) and the underlying mechanisms involved (Gurevitch et al., 2011; Rejmanek, 2011). Blackburn et al. (2011) proposed a highly cited and useful framework for biological invasions, where various terminologies for non-native species are associated throughout the different stages of an invasion. Therein, invasion state and impact are independent, because different populations can have measurable impacts at varying stages, acknowledging that all introduced species use resources and occupy space, thereby imposing some form of negative impact. While ‘invasive’ should be defined based on a population’s stage of an invasion and spread patterns, the exerted impact should be considered a separate dimension pertaining to a specific invading population. However, various populations can exert differing magnitudes of impact at different stages of an invasion over time, which depend on the type of impact and the specific features of the invaded ecosystem (Gallardo et al., 2016). Inferences of impact can also depend on perceptions and socio-economic evaluations (Falk-Petersen et al., 2006).

Yet, defining a non-native species’ invasiveness based exclusively on its ability to spread would imply that countless species qualify as ‘invasive’ as global (e.g. climate) change proceeds. Meanwhile, the focus on an identified impact could impede managers and stakeholders from acting until a negative impact is measured, such as for non-native species not currently spreading, but that cause local harm (Balzani et al., 2022). This *modus operandi* would, however, reinforce the current predominance of reactive management strategies for biological invasions, rather than proactive actions that could avoid later harm (Cuthbert et al., 2022). Proactive actions in managing biological invasions primarily encompass preventative approaches as well as early detection and rapid-response systems that are necessary for effectively mitigating potential impacts of non-native species (Cuthbert et al., 2022). Because all non-native species might have an impact at some point during the invasion process, such as by consuming resources or simply occupying space, the magnitude of impact can change unpredictably.

But measures of impact do not necessarily determine if a species is invasive, even though they are useful for assessing the risk of an invasion and are therefore commonly applied in risk analyses. To identify the invasion risk or the invasiveness of non-native species based on their observed or predicted impacts, various methods such as the Australian Weed Risk Assessment scheme (Pheloung, Williams & Halloy, 1999), the European and Mediterranean Plant Protection Organisation Platform on Pest Risk Analysis (Soliman et al., 2010), and related decision-support tools (Copp et al., 2016; Vilizzi et al., 2022b, 2024) have been developed. However, current risk-screening tools generally lack fully quantitative foundations, often incorporating qualitative information such as expert assessments due to limited tangible data or information on impacts (Roy et al., 2014, 2018). A knowledge gap arises from biassed impact research
<table><caption>Table 2. Published articles and books (arranged chronologically, without claiming completeness) that have highlighted the ongoing debate and confusion over terminology in invasion science, many of which aimed to standardise the invasion science lexicon.</caption><thead><tr><th>Year</th><th>Authors</th><th>Article type</th></tr></thead><tbody><tr><td>1995</td><td>Pyšek</td><td>On the terminology used in plant invasion studies</td></tr><tr><td>1997</td><td>Shigesada & Kawasaki</td><td>Biological invasions: theory and practice</td></tr><tr><td>1999</td><td>Lonsdale</td><td>Global patterns of plant invasions and the concept of invasibility</td></tr><tr><td>2000</td><td>Davis & Thompson</td><td>Eight ways to be a coloniser; two ways to be an invader: a proposed nomenclature scheme for invasion ecology</td></tr><tr><td>2000</td><td>Richardson et al.</td><td>Naturalisation and invasion of alien plants: concepts and definitions</td></tr><tr><td>2002</td><td>Carlton</td><td>Bioinvasion ecology: assessing invasion impact and scale</td></tr><tr><td>2004</td><td>Colautti & MacIsaac</td><td>A neutral terminology to define 'invasive' species</td></tr><tr><td>2004</td><td>Brown & Sax</td><td>An essay on some topics concerning invasive species</td></tr><tr><td>2004</td><td>Pyšek et al.</td><td>Alien plants in checklists and floras: towards better communication between taxonomists and ecologists</td></tr><tr><td>2005</td><td>Copp et al.</td><td>To be, or not to be, a non-native freshwater fish?</td></tr><tr><td>2005</td><td>Helmreich</td><td>How scientists think; about 'natives', for example. A problem of taxonomy among biologists of alien species in Hawaii</td></tr><tr><td>2006</td><td>Falk-Petersen et al.</td><td>On the numerous concepts in invasion biology</td></tr><tr><td>2007</td><td>Warren</td><td>Perspectives on the 'alien' versus 'native' species debate: A critique of concepts, language and practice.</td></tr><tr><td>2007</td><td>Ricciardi & Cohen</td><td>The invasiveness of an introduced species does not predict its impact.</td></tr><tr><td>2007</td><td>Larson</td><td>An alien approach to invasive species: objectivity and society in invasion biology.</td></tr><tr><td>2008</td><td>Valéry et al.</td><td>In search of a real definition of the biological invasion phenomenon itself.</td></tr><tr><td>2009</td><td>Colautti & Richardson</td><td>Subjectivity and flexibility in invasion terminology: too much of a good thing?</td></tr><tr><td>2009</td><td>Wilson et al.</td><td>Biogeographic concepts define invasion biology.</td></tr><tr><td>2009</td><td>Wilson et al.</td><td>Something in the way you move: dispersal pathways affect invasion success.</td></tr><tr><td>2011</td><td>Richardson et al.</td><td>A compendium of essential concepts and terminology in invasion ecology.</td></tr><tr><td>2011</td><td>Gurevitch et al.</td><td>Emergent insights from the synthesis of conceptual frameworks for biological invasions.</td></tr><tr><td>2013</td><td>Shackelford et al.</td><td>Finding a middle-ground: the native/non-native debate.</td></tr><tr><td>2013</td><td>Lockwood et al.</td><td>Invasion Ecology</td></tr><tr><td>2013</td><td>Heger et al.</td><td>What biological invasions 'are' is a matter of perspective.</td></tr><tr><td>2013</td><td>Richardson & Ricciardi</td><td>Misleading criticisms of invasion science: a field guide.</td></tr><tr><td>2013</td><td>Simberloff et al.</td><td>Impacts of biological invasions: what's what and the way forward.</td></tr><tr><td>2016</td><td>Robinson et al.</td><td>Lost in translation? Standardising the terminology used in marine invasion biology and updating South African alien species lists</td></tr><tr><td>2018</td><td>Essl et al.</td><td>Which taxa are alien? Criteria, applications, and uncertainties.</td></tr><tr><td>2019</td><td>Essl et al.</td><td>A conceptual framework for range-expanding species that track human-induced environmental change.</td></tr><tr><td>2019</td><td>Kapitza et al.</td><td>Research on the social perception of invasive species: A systematic literature review.</td></tr><tr><td>2019</td><td>Latombe et al.</td><td>A four-component classification of uncertainties in biological invasions: implications for management.</td></tr><tr><td>2020</td><td>Cassini</td><td>A review of the critics of invasion biology.</td></tr><tr><td>2020</td><td>Iannone et al.</td><td>Invasive species terminology: Standardising for stakeholder education.</td></tr><tr><td>2021</td><td>Essl et al.</td><td>Neonatives and translocated species: different terms are needed for different species categories in conservation policies.</td></tr><tr><td>2022</td><td>Lepczyk</td><td>Time to retire 'alien' from the invasion ecology lexicon.</td></tr><tr><td>2022</td><td>Shackleton et al.</td><td>Consensus and controversy in the discipline of invasion science.</td></tr><tr><td>2022</td><td>Golebie et al.</td><td>Words matter: a systematic review of communication in non-native aquatic species literature.</td></tr></tbody></table>

targeting specific taxa, regions, or values, further complicated by context-dependent and time-lagged effects. Unfortunately, the formal and reliable information required for accurate and objective assessments is

frequently lacking and/or is (spatially) incomplete for many non-native species, resulting in discrepancies among inadequate spatial risk and impact assessments (González-Moreno et al., 2019).
(2) Language as a source of ambiguity

The circulation of many English terms and their translations
can introduce ambiguity and hinder public engagement with
diverse audiences. For instance, describing a species as
'exotic' can be perceived differently and carry positive
connotations in several languages (like English, Portuguese,
Italian, Czech or Spanish), such as 'extravagant', 'fancy',
and/or 'unique'. On the other hand, the dominance of
English in scientific publishing implies that the meaning
of terms with different connotations (often with no direct
translation) in other languages will inevitably be unclear,
while it can concomitantly impede effective transfer of infor-
mation and create knowledge gaps [e.g. regarding the
impacts of invasive species (Bortolus, 2012; Angulo
et al., 2021; Nuñez et al., 2022)]. For instance, many of the
current debates about disciplinary denialism, the misleading
xenophobic formulation of analogies with international
human migration, and the impact of using emotive language,
are likely exacerbated by culture and translation (Copp
et al., 2021; Bortolus & Schwindt, 2022). Indeed, many issues
of terminological ambiguity and epistemic injustice arise
from the pervasive 'diffusion of English' approach in scien-
tific research and terminology being published, reviewed,
and accepted almost exclusively in English. This was recently
addressed with an application of the 'ecology of language'
paradigm to the development of a multilingual decision-
support tool for communicating the risks of invasive species
to decision-makers and stakeholders in their native language
(Copp et al., 2021). In this complex multicultural and
multi-linguistic scenario, one must accept that (i) consensus
concepts published in English might not be ideal in
other languages, philosophical frameworks, and cultures,
and (ii) the aim is to achieve consensus of conceptual defini-
tion rather than on terms *per se*. Reviewing, comparing, and
reaching agreements on definitions, as well as establishing
precise regulations for translating technical terminology into
various languages worldwide, constitutes an essential, but not
easy, step.

‘Exotic’ and ‘alien’ denote species that have been intro-
duced to a region outside their native ranges (Florencio,
Lobo & Bini, 2019). However, using ‘alien’ in public dis-
course is potentially confusing because it: (i) is sometimes syn-
onymous with ‘extraterrestrial’, therefore potentially
confusing (Lepczyk, 2022); (ii) has socio-political connota-
tions and legal implications in human immigration policies;
and (iii) can limit the application of Indigenous People’s
frameworks and management and impede biodiversity pro-
tection (Wehi et al., 2023). This occurs because of the dichot-
omous portrayal of ‘aliens’ and ‘natives’ that echoes
detrimental historical narratives and marginalises Indigenous
stewardship, posing a barrier to protection of biodiversity
(Warren, 2007; Wehi et al., 2023). ‘Non-indigenous’
should not be considered a synonym of ‘alien’ species
(Kolar & Lodge, 2001) because ‘non-indigenous’ also has
a socio-political interpretation, particularly in light of the
growing recognition and awareness of Indigenous rights

(Wehi *et al.*, 2023), political correctness, and the increasing
popularity of the diversity, equity, and inclusion agenda
within academia. Even terms like ‘colonise’ to describe pro-
cesses of pre-colonial human movements are falling out of
favour in disciplines such as anthropology and archaeology
given their association with colonial injustices.

A possible alternative would be ‘allochthonous’ (*contra*
‘autochthonous’), an established term in freshwater ecology.
‘Allochthonous’ is not (yet) politically charged; it is derived
from the Greek *allos* (άλλος, meaning ‘other’ or ‘different’)
and *chthon* (χθών, meaning ‘Earth’ or ‘land’), and is com-
monly used in geology and ecology to describe something that
originates or is formed in a location different from where it is
currently found (displaced). However, this term is not in com-
mon usage and difficult to pronounce in or translate to non-
Romance languages, and is therefore unlikely to become part
of the public discourse, even though it is well-established among
experts in some countries (e.g. France, Serbia, Spain, Italy).

Other terms focus on the capacity of a species to spread,
such as ‘escaped’ (Table 1) and ‘introduced’, which strictly
address the act of intentional or unintentional introduction
of an organism by humans into an environment where it
did not occur naturally (Simberloff, Parker & Windle,
2005). ‘Naturalised’, favoured by the ‘naturalisation and
acclimatisation’ societies of the 19th and 20th centuries, not
only mixes concepts related to the ability to spread and estab-
lish, but also how long a given species has been present in the
new environment such that people perceive it as part of
the native community – e.g. dingo *Canis dingo* in Australia
(Smith *et al.*, 2019), North American ash-leaved maple *Acer
negundo* in Russia (Vinogradova, 2006), and the smooth cord-
grass *Spartina alterniflora* in South America (Bortolus,
Carlton & Schwindt, 2015). ‘Naturalised’ describes a non-
native species that has successfully established self-sustaining
populations in the wild following introduction (Falk-Petersen
et al., 2006), yet despite still being non-native, it sometimes
attracts the same legal protection as native species
(e.g. fallow deer *Dama dama* in the UK; Manchester &
Bullock, 2000). However, other definitions have been applied
to describe the naturalisation phenomenon: (i) species that
are non-native and reproduce in environments aided by
human cultivation; (ii) a group of non-native species that
propagate in natural or semi-natural environments; (iii) spe-
cies that exist outside their native regions, with their repro-
ductive success varying; or (iv) non-native species that have
broadened their geographic distribution (see Richardson
et al., 2000). Carlton (2009) disapproved of the terms ‘natur-
alised’ and ‘resident’, asserting that these do not constitute
distinct categories within the realms of biogeography, ecol-
ogy, environment, history, or evolutionary status, arguing
instead that identifiable species should be categorised as
either ‘native’, ‘introduced’, or ‘cryptogenic’.

Terms applied less frequently but subjected to linguistic
ambiguity include ‘noxious’ to refer to species that are harm-
ful or dangerous to humans (Andreu, Vilà & Hulme, 2009),
‘foreign’ to denote species originating from a different
geographical location (Iannone III *et al.*, 2020), ‘adventive’ to refer to species that have been introduced to a new area but have not yet become invasive (Frank & McCoy, 1990; Klimaszewski, Bourdon & Pelletier, 2013), and the cultural terms ‘pest’ or ‘weed’ not necessarily related only to non-native species (Richardson *et al.*, 2011), but often used for native insects, rodents, or widespread plant species with a negative impact on agricultural production, forestry, or urban ecosystems (Worner & Gevrey, 2006).

## IV. SEPARATING IDEOLOGY FROM TERMINOLOGY

The emergence of novel terminology deviating from established definitions, as well as certain terms that broadly promote ‘political correctness’ (Klotz, 1999; Wagner, 2005; Pace & Severance, 2016), denotes linguistic change. Such terms can have negative connotations and are therefore criticised (Colautti & MacIsaac, 2004; Lieurance *et al.*, 2022). This has been argued for terms like ‘alien’ (Lockwood *et al.*, 2013), and even ‘invasive’, which have been misused by populists and politicians (Schlaepfer, Sax & Olden, 2011; Sax, Schlaepfer & Olden, 2022) to advance ideologically based policies (Larson, 2005). The term ‘invasive’ itself is defined as ‘… (especially of diseases within the body) spreading very quickly and difficult to stop’ (Oxford English Dictionary Online, 2023). According to Cambridge English Dictionary Online (2023), ‘… an invasive organism is one that has arrived in a place from somewhere else and has a harmful effect on that place’. Concomitantly, it is also connected to hostile (e.g. military) actions or directly from Medical Latin *invasivus* meaning ‘tending to invade, aggressive’ (Weekley, 1921). ‘Invasive’ has been used in pathology (since the 1920s) and medicine (since the 1970s), and refers to both (*i*) propagation and (*u*) harmfulness (Oxford English Dictionary Online, 2023). ‘Invasive’, when used by invasion scientists to describe non-native species, can create confusion because it might be interpreted as pertaining only to spread, or incorrectly associated with negative impacts, or both.

While the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) uses the terms ‘alien’ and ‘invasive’ in its reports (aligning with the terminology used in the Convention on Biological Diversity), some scientific journals are already banning terms such as ‘alien’ due to its value-laden nature. It is therefore unfortunate that some international bodies still actively promote such terms, because they can obfuscate discourse, fuel divisiveness, and undermine the principles of constructive dialogue and understanding. Rather than fostering healthy debates, such terminology serves only to entrench biases, deepen resentment, and polarise communities, nor does it align with principles fostering a balanced and informed discourse. While top-down initiatives echo recent calls to steer away from such concepts and terms in ecology (Ellwood *et al.*, 2023), creating language rules and enforcing verbal hygiene can be

disadvantageous by hindering open dialogue, stifling diverse perspectives, and impeding the advancement of knowledge (Cameron, 2012). In his 2022 address to the Convention on Biological Diversity–Global Biodiversity Facility negotiations in Montreal, the Secretary-General of the United Nations António Guterres used the term ‘invasive non-native species’. The negative connotations of several terms used by invasion scientists possibly also take root from using ‘invasive species’ for the taxon as a whole, instead of ‘invasive population’, for example. No species is invasive *per se* (i.e. being native in their original range and not necessarily invasive everywhere where they are introduced; Colautti & MacIsaac, 2004) and notable impacts within populations can be triggered by environmental changes or trait evolution (Cuthbert *et al.*, 2023).

### (1) Avoiding problematic terminology

Different languages can employ different terms, and the translation between English and other languages can cause confusion (see Section III.2). This creates challenges when addressing non-native species, such as geographical and historical differences in the use of terminology (Richardson *et al.*, 2011). To foster clarity and progress while enhancing communication and comprehension, we propose avoiding historically problematic, redundant, and/or confusing terminologies especially, but not only, when non-native species are listed in different categories for management (Table 3). While clarifying the meaning of terms used in studies on biological invasions, we suggest avoiding ‘Lessepsian migration’ (Por, 1971) in view of the controversial history of Viscount Ferdinand Marie de Lesseps. As one of the founders of the ‘Compagnie Universelle du Canal maritime de Suez’, Lesseps was responsible for wide-scale exploitation of unpaid forced labour (Brown, 1994; Farouk, 2019; Ortiz-Serrano & Forero-Laverde, 2020). ‘Lessepsian’ glorifies the person and his actions, thereby perpetuating a legacy of European imperialism and corruption. A replacement term could be ‘Suezian non-native migration’. Our proposed terminology attempts to overcome problematic terms, but also redundancies and ambiguities, and these terms classifying species in categories should be limited or eliminated entirely in invasion science, especially when using them to describe the invasiveness of a non-native species. Specifically, we propose to avoid the terms listed in Table 3 (especially when presented without context; e.g. Latombe *et al.*, 2019) to classify a non-native species, or to consider their use carefully and contextualise appropriately.

### (2) Conundrum of nativeness and non-nativeness

The dichotomy of ‘non-native’ and ‘native’ species can often be applied effectively at broader scales (e.g. continental) where clear biogeographical units are considered, while evolutionary boundaries are sub-continental for many taxa (especially in fresh waters) and are therefore more complex to delimit due to ecological, genetic, or taphonomic variation (Lockwood *et al.*, 2013; Stigall, 2019; Lemoine &
<table><caption>Table 3. Terminology used by invasion scientists to describe non-native species that we suggest should be avoided because of the likelihood it will perpetuate confusion or offend. Otherwise, authors should carefully consider their use and explain appropriately the specific context to avoid misunderstandings, confusion, and controversy.</caption><thead><tr><th>Term(s)</th><th>Reason</th></tr></thead><tbody><tr><td>alien, foreign, non-indigenous, exotic</td><td>Often used interchangeably, and synonymous with <strong>non-native</strong>, leading to potential confusion and ideological or political misuse</td></tr><tr><td>alien (including invasive alien), extralimital, immigrant, migrant, unwanted</td><td>Politicised with socio-political connotations often used in context of human migration; alien can also be confused with 'extraterrestrial being' in public discourse</td></tr><tr><td>acclimatised, adventive, anthropochore, established alien, intra-country, non-resident, transformer, bioinvader, biopollution, coloniser, tramp, vagrant, waif, xenobiota</td><td>Also used in other contexts, creating ambiguity</td></tr><tr><td>casual, escaped, imported, neobiota, released, translocated, transferred, transported, transplanted, transient, vagrant, vermin, waif</td><td>Do not indicate the invasive potential or establishment of the species</td></tr><tr><td>established, naturalised, questionable, transient</td><td>Without context, remain too open to interpretation (subjective); note difference to <strong>established non-native</strong> proposed herein (see Table 4)</td></tr><tr><td>noxious, nuisance, pest, weed</td><td>(Legal) terms often used to describe harmful or destructive species; as not all <strong>non-native</strong> species are designated <strong>noxious</strong>, its use requires context</td></tr><tr><td>neonative, new non-native, newcomer, non-resident, restocked</td><td>Impractical, because human-caused climate disruption drives species distributional shifts, including species that are ecologically and phylogenetically distinct from resident native species; some of these species will become disruptive to ecosystems for the same reasons that cause <strong>invasive non-native</strong> species to do so; poorly linked and often conflicting with science, policy, and management</td></tr></tbody></table>

*Note*: Italics refer to terms identified in this paper as problematic (e.g., redundant).

Svenning, 2022). Furthermore, classification becomes more complex at finer scales where the boundaries between native and non-native ranges are more difficult to delineate (Lockwood et al., 2013; Brodie et al., 2021). However, the fact that a species' native range might be challenging to observe from a human perspective does not imply that nativeness must possess a gradation terminology beyond an inherently binary state – either it is native or it is not. While it is generally advantageous to define the native range of a species as temporally and spatially static (Pereyra, 2020), the concept of 'nativeness' should be interpreted as an eco-evolutionary continuum. This implies that an unambiguous categorisation of a species as native or non-native might not always be feasible due to varying ecological and evolutionary factors. This complexity arises, for instance, when species expand their native ranges within the same country or region due to human modification of the environment and/or climate change (Clements & Ditommaso, 2011; Saikkonen et al., 2012), possibly tracking their historical niches when the rates of environmental alteration exceed adaptation to those changes (Thomas, 2010), or when the biogeography of so-called 'cosmopolitan' species (distributed in most or all regions of the globe) is not well-resolved (Cerca, Purschke & Struck, 2018; cf. Darling & Carlton, 2018). Nevertheless, addressing these classification issues could not be resolved with a broad range of naming conventions for these organisms as a way to offset the limited understanding of the human role in their distribution. For practical applications, we therefore support a dichotomous

categorisation ('native' or 'non-native') while still acknowledging the inherent ambiguities.

The newest term debated in the invasion lexicon is 'neonative' – referring to species that move on their own beyond their present natural range due to human-induced environmental changes (Wilson, 2020; Essl et al., 2019, 2020, 2021b). 'Neonative' was proposed to distinguish species moved through human agency (i.e. 'non-native') and range-expanding native species responding to human-caused environmental (local) and climate (global) changes (Essl et al., 2019; Urban, 2020). However, it is often challenging to distinguish between the observation and status of species moving naturally from those shifted passively or actively by human endeavour (i.e. as a result of human-assisted pathways; Essl et al., 2019). This differs from the proposed approach of Gilroy, Avery & Lockwood (2017), who did not deal with the issue of intermediate populations (i.e. 'stepping stones'; Floerl et al., 2009), but defined all species transported outside their native ranges by direct transport as 'non-native', leaving species moving *via* unassisted dispersal as 'natives'.

If we consider species as 'non-native' based on their evolutionary lineage and native habitat, disregarding the mechanism of their dispersal, invasions resulting from establishment after a long-range dispersal, akin to anthropogenically facilitated extinctions and climate change, have been a persistent aspect throughout the history of life on Earth (Stigall, 2019). Just as human activities affect current rates of extinction and climate change, they also influence the rate, scale, and impact of biological invasions (Ricciardi, 2007).
By viewing ‘non-native’ species in terms of evolutionary history, invasions can be understood as species settling populations outside their conventional biogeographic and evolutionary limits. Consequently, not every occurrence of range expansion can be classified as an invasion because all species experience natural range variation given enough time (Wilson, 1961). Yet, regardless of the reasons or processes involved, all invasions are indeed a form of range expansion (Ricciardi, 2007; Beest et al., 2013). ‘Neonative’ is therefore impractical and weakly linked to policy and management [Wilson (2020), cf. Lenoir et al. (2020) for debate].

We recommend that ‘neonative’ should be used only to label native taxa undergoing climate-induced range extensions. But it should not be used to classify non-native species spreading *via* human-made pathways after an environmental barrier is removed, because this would overlook rapid, contemporary climate change driving some invasions and the erosion of biogeographic barriers *via* human influence. Assuming that the defining characteristic of ‘non-native’ is solely from direct, human-mediated dispersal, we would have to treat those species moving autonomously in response to shifting environmental conditions along human-made pathways like canals as natives, irrespective of human involvement in climate change. Endorsing this argument would require categorising all species independently moving through canals as ‘native’. While the movement of ‘neonatives’ might be necessary to avoid extinctions [e.g. ‘assisted migration’ (cf. Hällfors et al., 2014; Pereyra, 2020)], these populations can cause ecological disruptions once established (Forgione, Bacher & Vimercati, 2022), but might simultaneously require protection given threats in their native ranges (Essl et al., 2021b; Forgione et al., 2022). The conundrum arises from the origin of environmental or climatic changes, which might also be considered anthropogenic, thereby blurring the distinction between ‘neonative’ and ‘non-native’.

Terminological complications are exacerbated by the complexity of reintroductions of non-native populations of historically native species translocated for conservation (Essl et al., 2021b). Stocking practices in recreational and commercial fisheries (Tarkan et al., 2017), or rewilding (Corlett, 2016) produce similar and recurring terminological problems. Such species fall under the definition of ‘non-native’, as in the case of the wild boar *Sus scrofa* in Ireland introduced into a new area by direct human action. For conservation and management purposes, they are however often misleadingly classified as Archeobiota (Essl, Glaser & Schertler, 2021a) rather than ‘non-native’ because they naturally inhabited Ireland in the past (before the 12th century). Inversely, the white-clawed crayfish *Austropotamobius pallipes* is considered native and threatened in Ireland, but was introduced from France in the Middle Ages (Gouin et al., 2001).

‘Native invaders’, ‘invasive natives’, ‘native super-dominants’ (Carey et al., 2012; Pivello et al., 2018), and ‘new natives’ (Lemoine & Svenning, 2022) describing native species that have expanded their ranges due to human-mediated dispersal or environmental changes are problematic because they blur the distinction between naturally evolving

ecosystems and those impacted by humans (even those that happened hundreds or thousands of years ago; Bucher & Aramburú, 2014). Conflating natural range shifts with invasive behaviours by ignoring the species' respective evolutionary history could compromise conservation management. Native species can expand their ranges in response to shifting environmental conditions, and such movements do not necessarily imply negative impacts on ecosystems.

## V. PROPOSAL FOR A SIMPLIFIED TERMINOLOGY

All aforementioned initiatives and frameworks emphasised the need for more openness, neutrality, and consistency in invasion science, because no scientific discipline should continuously commiserate over the lack of clear definitions without constructive progress. By revitalising the approach of Colautti & MacIsaac (2004), we attempt to avoid redundant and potentially offensive terms in invasion science and provide clear and standardised definitions of invasion terms. While we acknowledge that our proposed updates will not necessarily replace the existing lexicon, our primary aim is to improve the consistency and definitive base for future terminology, while advocating the acceptance of pluralism as long as definitions are clear. This does not mean that a population of a ‘non-native’ species cannot be described as ‘naturalised’ or ‘pest’ (for example) in a given region or country to mean that it has achieved a self-sustaining population or report its socio-economic impact (as in the case for the ring-necked pheasant *Phasianus colchicus* in North America; Taylor, 2023), but that the species should not be labelled ‘naturalised’ or ‘pest’, thereby blurring an otherwise clear terminology.

We therefore encourage the use of a restricted and controlled terminology (Table 4) to reduce confusion and avoid superfluous terms such as ‘unwanted’, and ‘imported’ species (Table 3), because they are synonymous with more commonplace but politicised terms (such as ‘alien’). To simplify and streamline the terminology, especially when communicating with the public, stakeholders, policy makers, or other officials, we recommend adopting an acceptable, clear, and concise framework for journal editors, stakeholders, and scientists alike, which could be linked to existing biodiversity standards, particularly the Darwin Core terms (Groom et al., 2019). Invasion scientists often need to communicate the outcomes of their findings in a clear, detailed, and educational way to decision-makers and the public in languages other than English. In these cases, adopting the minimalist set of terms we propose will facilitate translation from the original English (see Table S1) and avoid the ambiguities that result from politically and/or culturally laden terms not available in those languages (see Copp et al., 2021).

We propose that ‘non-native’ should focus primarily on describing the evolutionary relationship of a species to the biogeographic area in which it originally did not evolve,
<table><caption>Table 4. Proposed basic terminology for classifying populations of non-native species. These terms are hierarchical – a subset of all *non-native* species will become *established non-native* species, and a subset of those will become *invasive non-native species*. The terms highlighted in italics and bold indicate cases where particular terms are themselves used as definitions. For proposed translations of the terminology suggested here, see Table S1.</caption><thead><tr><th>Term</th><th>Definition</th><th>Reason/application</th></tr></thead><tbody><tr><td><strong>non-native</strong></td><td>Present in or arriving to an area to which it is not native (has no evolutionary history there) either by (i) being introduced through direct human activities, or (ii) 'natural' dispersal after a biogeographic barrier is removed, or across a created pathway after an artificial environmental gradient is removed following human intervention</td><td>Useful because it specifies a step in the invasion process – the introduction of a species outside its native range. It is used when an individual or population is first reported and its status is undetermined (e.g. found in only one collection, year, location), hence lacking evidence for establishment.</td></tr><tr><td><strong>established non-native</strong></td><td>A <strong>non-native</strong> species that reproduces (≥n generations) in an area to which it is not native (has no evolutionary history there), but is currently not spreading or spread is unknown</td><td>Differentiates populations of non-native species that have arrived in a new environment and are confined to a location or area from those that reproduce and sustain populations over continuous life cycles (depending on the species, e.g. in several collections in separate years in the same location) without direct intervention by humans.</td></tr><tr><td><strong>invasive non-native*</strong></td><td>An <strong>established non-native</strong> species that spreads (actively or passively), resulting in the establishment of successive populations beyond the introduction point(s)</td><td>Underscores the ability of a population of a non-native species to colonise, establish, and spread. While any population of a non-native species can be introduced into a new environment, not all will be able to survive and reproduce successfully in the new area. It is the species that establish self-sustaining populations and spread further from the introduction point that become invasive.</td></tr></tbody></table>

*Note:* Impact can occur at any of the stages during the process of biological invasion and is not confined to the 'invasive' stage. Impacts can vary due to a change in the abundance and spread of the 'invasive' species. However, definitions of 'invasive' have often only considered impact, which can obfuscate the full scope of the biological invasion process. An established or invasive non-native species might not always be immediately or obviously harmful, because non-native species can cause more damage as environmental conditions change or as adaptations occur. At the same time, it is possible that a non-native species remains confined to one locality, where it has a severe impact on its recipient ecosystem, without being classifiable as 'invasive'.

*'Invasive non-native species' is used for clarity and specificity; however, where context permits, the term can be abbreviated to 'invasive species'.

concomitantly acknowledging the importance of human-mediated dispersal for modern invasions. The term 'invasiveness' should denote a population's ability to colonise, establish, and spread, possibly encompassing the criterion of 'superabundance' (i.e. a species that has exceeded its normal carrying capacity due to favourable conditions, resulting in potential ecological imbalances; Ricciardi & Cohen, 2007; Aizen et al., 2014).

This produces the following terms when classifying populations, which should not be abbreviated as acronyms or initialisms because they confuse and provide no additional value: *non-native*, referring to species that have been actively or passively translocated and released through human action beyond their known historical and natural range without the necessity of establishing in the new environment; *established non-native* to signify a non-native species that has successfully established in the area where it was introduced, evidenced by the presence of a self-sustaining population; and *invasive non-native*, representing those populations of established non-native species that are currently spreading or have recently spread (see Section V.1 for the concept of spread) in their invaded range (Table 4). The 'invasive' condition varies

temporally as well as spatially; i.e. a non-native population that has long maintained low abundance or remained largely confined to a specific region can suddenly undergo explosive growth (e.g. Witte et al., 2010) or expand well beyond its historical range (e.g. *Ficus* spp. following the arrival of their coevolved pollinator chalcidoid fig wasps; Nadel, Frank & Knight, 1992). Initially non-invasive, or even considered benign, these populations can become invasive later due to triggering factors (Spear et al., 2021). Similarly, a population that has demonstrated invasiveness for an extended period can later stop spreading or diminish in abundance – for instance, following the introduction of an effective control agent or after encountering physical or ecological constraints. Such populations could become invasive once more if constraints are removed (e.g. sea lamprey *Petromyzon marinus* in the Great Lakes after control was suspended during the COVID-19 pandemic) (Sullivan et al., 2021).

If a non-native species' invasiveness is solely defined by its ability to spread, 'invasive non-native' could be replaced with 'spreading non-native'. However, 'spreading non-native' is redundant because almost all 'established non-native' species eventually spread, albeit at variable rates,
within the geographical and ecophysiological limits imposed by their new environment. If defined exclusively by the process of invasion (Ricciardi & Cohen, 2007), 'invasive' can be used to distinguish (and even rank) those species that have higher rates of establishment than others, or populations that have higher rates of spread than others. 'Invasive' could also be used to describe a non-native population that has suddenly begun to expand rapidly or become superabundant within a region after having remained at low densities prior to being triggered to increase following environmental (Spear et al., 2021) or anthropogenic changes (Bortolus, 2006). The absence of consensus among invasion scientists on objective, quantitative definitions for 'impact' and 'spread' has hindered progress in the conceptual understanding of populations being 'invasive'. The continuum of both 'spread' and 'impact' has lacked clearly definitive boundaries, mediated by many context dependencies. Defining 'invasive' based solely on 'spread' would include many non-native species with potentially negligible effects on human society and biota, while defining it solely on 'impact' would yield similar outcomes because all non-native species eventually cause impacts by occupying space or using resources, albeit possibly perceived as inconsequential to humans. Combining the two debated concepts would not resolve, but exacerbate, these challenges because some species spread and establish faster than others, while some exert larger or more observable impacts than others regardless of their dispersal ability. While the concepts of 'spread' and 'impact' are impossible to disentangle, the invasiveness of a species can best be defined as an ability to colonise, establish, and spread, which are integral components of the invasion process (Blackburn et al., 2011). Further, Ricciardi & Cohen (2007) found no relationship between characteristics of invasiveness (establishment success and rate of spread) and impact on biodiversity. They concluded that non-native species that spread and establish quickly are not necessarily the ones causing measurable ecological changes, although they could have larger cumulative impacts over broader spatial or temporal scales. Constructing a comprehensive table of definitions and terminology using both spread and impact is therefore infeasible. Instead, spread is more suitable for objective measurement in the context of biological invasions, with impact being a separate dimension that is not as well studied (acknowledging that all non-native species can exert a negative impact at some point).

While acknowledging the existence of sub-categories of invasions, such as 'failed' invasions (Zenni & Nuñez, 2013), or knowledge gaps where the establishment status or point of introduction is unknown, only a small proportion of the many introduced 'non-native' species eventually establishes and becomes invasive. This subset varies among ecosystems, regions, and other relevant contexts and is influenced by modes of introduction that affect propagule pressure and repeat inoculation events (Williamson & Fitter, 1996). Other than in some special cases (e.g. in isolated and altered micro-habitats such as thermal springs or artificially heated out-flows; Aksu et al., 2021), establishment results in the spread

of the non-native species, and hence, potential invasiveness. This suggests that populations of 'established non-native' species that remain in this category are rare in reality because most populations of such species spread to some extent at some point after their arrival. Rare examples to the contrary include populations of warm-water species that were originally used as ornamental species and that established in thermally polluted waters [e.g. power plant discharge (Yanygina, Kirillov & Zarnbina, 2010; Klotz et al., 2013; Castañeda et al., 2018)], but are restricted to the artificially heated environments or eventually went extinct (Castañeda et al., 2018). The mosquitofish Gambusia spp. introduced to a canal in Liverpool (UK) due to the closure of a pet shop, failed to spread beyond the introduction site (Vale Gordon H. Copp, personal communication). Another example is the golden clam Corbicula fluminea that invaded a section of the Saint Lawrence River immediately downstream of a nuclear power plant, established, but was extirpated after the plant shut down (Castañeda et al., 2018). Besides thermally polluted environments, an array of other examples of populations of 'established non-native' species are found in natural thermal springs (Yanygina et al., 2010; Bláha et al., 2022). The status as 'established non-native' is however profoundly influenced by its context and location. For instance, the red-eared slider Trachemys scripta (Ryan et al., 2008) or the eastern mudminnow Umbra pygmaea (Haubrock et al., 2023), often found established in isolated ponds, present a different scenario compared to many non-native fish species established within entire freshwater ecosystems. This contrast highlights the importance of perspective (i.e. local versus regional establishment) when classifying non-native species. Yet, cases satisfying the 'established non-native' criteria might disappear over time because self-sustaining populations do not establish under limited conditions (e.g. limited space), thereby being classified as a 'failed invasion'. Alternatively, an 'established non-native' species can adapt to less-favourable environments, and potentially become an 'invasive' population (Vandepitte et al., 2014; Weipert et al., 2019), while potentially (even if only temporarily) returning to the 'established non-native' status once reaching a constraint or barrier. Most island introductions would qualify as 'invasive' species, having spread within, around, and on a given island.

## (1) Conceptualising invasive species and spread

The concept of 'spread' in invasion ecology is important because it refers to the movement and dispersal of a non-native species beyond its original point of introduction (Wilson et al., 2009a; Hui & Richardson, 2017), forming the basis for the classifications of 'non-native' populations as 'invasive'. Therefore, invasions must first be considered a population-level phenomenon, and then a context-dependent, species-level phenomenon. While it appears intuitive that a species' spread within biogeographical and administrative boundaries (and not its impact) constitutes the final stage of the invasion process biologically, and thus merits the classification 'invasive', quantifying the parameters and thresholds that
define spread lacks resolution and likely differs among habitats, taxa, regions, and other contexts (Shigesada & Kawasaki, 1997; Suarez, Holway & Case, 2001; With, 2002). Furthermore, an ill-defined conceptualisation of ‘spread’, and possibly multiple introductions, make it challenging to measure spread rates (Hengeveld, 1992). Estimates of spread rate are however essential to validate and advance theoretical models predicting spatial patterns that arise from invasions (Hastings, 1996; Lewis, Petrovskii & Potts, 2016).

While spread can be defined as the dispersal of a species beyond its introduction point or natural range, the identification of the latter is challenging for many species. This is especially the case in aquatic or terrestrial ecosystems in developing countries where non-native species are often detected when they are already abundant and widespread. When the location and date of introduction are unknown or anecdotal, an alternative is to default to the earliest recorded instance of the species as a proxy (e.g. Vargas et al., 2022). This information, coupled with ecological investigations that elucidate the species' dispersal capabilities, could potentially shed light on whether it has spread outward from its point of introduction. The introduction point requires context-specific interpretation due to its relative nature. In some cases there could be several points of introduction (Sax et al., 2005) arising from separating primary (initial human-mediated introduction of a non-native species) and secondary spread (subsequent dispersal within the new environment or to neighbouring environments). Determining the dispersal mechanism – specifically the importance of ‘jump’ dispersal versus ‘diffusive’ range extension (Borchering et al., 2011; Reynolds, 2012; Liebhold et al., 2017) – is needed to disentangle issues associated with primary and secondary spread (Bartumeus et al., 2005; Viswanathan et al., 2011).

For terrestrial invasive non-native species, spread is commonly quantified as the distance from the introduction point (Renault, 2020). However, the relationship between spread and invasive species becomes more complex in the aquatic realm. For a bay or stream, the definition of spread is often subjective; not only are points of introduction poorly resolved, there is also no consensus on the criteria for designating a species as ‘invasive’ based on spread within these environments. In freshwater environments, spread can occur within and among water bodies, both qualifying as criteria for invasiveness. For ponds and lakes, the same principle applies as for islands within an archipelago, because spread includes dispersal between insular ecosystems such as lakes and islands and homogeneous diffusion within them (e.g. American bullfrog *Lithobates catesbeianus* in Uruguay; Laufer et al., 2023).

A comprehensive and accepted definition of spread that accounts for its nuances among different life forms, realms, habitats, and biomes is needed to ensure clarity in the classification of invasive species. Without a clear definition of spread and knowledge of an invasive species' rate of spread per unit time (Richardson et al., 2000, 2020), 'invasive' can be subjective and ambiguous. Spread is ultimately limited

by geographical and ecophysiological boundaries, but also depends on species-specific dispersal. The rate of spread per unit time can differ depending on traits such as size, means of locomotion, or life stage. Neither is spread necessarily continuous, for it can fluctuate over time. To avoid ambiguity, we suggest that when a species or population is reported as 'invasive' (especially for the first time), the reporting authority should state the evidence for and scale of spread (Gago et al., 2016; Gkenas et al., 2024).

## (2) Conceptualising invader impacts and the importance for management

While the descriptor ‘invasive’ is based on a population’s stage of invasion, different populations can be in different stages of the invasion process (Blackburn et al., 2011; Essl et al., 2011; Spear et al., 2021), leading to conflicting perceptions about their impacts (e.g. ‘double-edge’ invasive non-native species; Kourantidou et al., 2022). Prior to introduction (and dispersal), management should focus on prevention, but once a population is established, management should shift to eradication, or at least to density reduction and containment if substantial spread has already occurred. Both population growth and spread indicate a species’ abundance (which can modulate a population’s impact significantly; see Fig. 3; Soto et al., 2023a) and geographical expansion, but they do not necessarily determine impacts that are instead dictated more by the characteristics of the invaded ecosystem and how societies perceive and evaluate impacts economically (Falk-Petersen et al., 2006; Gallardo et al., 2016).

While the ‘invasive’ label should primarily refer to the spread stage of a non-native population, the real or perceived impact of that invasive population represents a second dimension. Evaluating a species’ impact can be subjective (Turbé et al., 2017) because (i) impact assessments are usually done at a local scale by targeting populations, and focus on specific areas where spread is confined by the boundaries of the ecosystem unless anthropogenically facilitated (Turner, 1996; Echeverría et al., 2006), and (ii) total impacts are often inferred by extrapolating local-scale measurements of ecological effects and invader abundances to larger regions, neglecting potential spatial variation (Howard et al., 2018; Haubrock et al., 2022; Ahmed et al., 2023; Soto et al., 2023b), as well as non-linear impact-abundance relationships (Sofaer, Jarnevich & Pearse, 2018). Schemes such as the *Environmental Impact Classification for Alien Taxa* [EICAT (Hawkins et al., 2015); EICAT+ (Vimercati et al., 2022)] and the *Socio-Economic Impact Classification of Alien Taxa* (SEICAT; Bacher et al., 2018) have fortunately advanced the complex task of quantifying the impacts of invasions.

Management decisions often rely on perceived and subjective impacts, indicating that the goal of management has shifted from limiting spread to curtailing damage, particularly where limited resources necessitate efficient prioritisation among many species and populations (Kueffer & Daehler, 2009; García-Díaz et al., 2021). Impacts can be
<figure><img src="image_5.png" /><figcaption>**Fig. 3.** Invasion (impact) curve conceptually illustrating the abundance or invaded area as well as cumulative impact over time as a sigmoidal function. We divide the invasion curve into three phases: establishment, exponential growth, and equilibration. The red areas indicate the hypothetical population-level distribution/impact of these phases. Adapted from Haubrock *et al.* (2022).</figcaption></figure>

context-dependent, time-lagged, and co-mingled with other stressors, but as long as a species' invasiveness is contingent on its impact or quantified risk, management is handicapped. The spread-based term 'invasive' might therefore lose relevance in management, particularly when directed towards populations perceived as highly impactful. The issue of spread-based decisions in the management of 'invasive' species (Epanchin-Niell & Hastings, 2010) is further complicated because the concept of spread itself is ambiguous among scales and environments.

An alternative is to assume that all established non-native species have negative impacts, and management interventions should be considered for those populations that are spreading, unless evidence demonstrates that their spread does not cause negative impacts. However, determining the potential impacts of all established non-native species during their spread can be complex and resource intensive. Meanwhile, possible pre-invasion 'deny list' (lists of species prohibited for import) approaches to management following invasion might become impractical when applied over broad spatial scales (e.g. political entities like the European Union or USA), because assessment outcomes might vary among ecosystems, biogeographic regions, and value systems (Rilov et al., 2024). This issue is exacerbated by benefits perceived from invasive species due to human interest in some socio-economic sectors (e.g. fisheries or ornamental trade), as well as in climate-change hotspots where thermally sensitive native species are extirpated and thermophilic invaders with similar traits take their place, or where native species are the minority (Rodríguez-Barreras et al., 2020). Perceived and real benefits can obfuscate the negative effects at the expense of environmental degradation and community well-being (Mwangi & Swallow, 2008), presenting another challenge for management (Shackleton et al., 2019; Wehi et al., 2023) and creating difficulties in establishing universal criteria for management decisions that should be based on the species' invasion

potential and any ecological and socio-economic impacts (Sandvik *et al.*, 2019).

Adopting a unified approach assuming that all established populations of non-native species will ultimately have a negative impact would lead to ineffective resource allocation and hinder the prioritisation of 'high-risk invaders' – non-native species that spread rapidly, thrive in new environments, and exert large negative impacts. The primary aim should therefore be the prevention of both species-specific vectors and pathways. Emphasising shifts in invasion pathways and vectors over time, along with their associated species, is important because problematic species likely entered through historical routes that might be less relevant today. Managers, stakeholders, and scientists should subsequently base decisions on changes in population size, the population's potential to spread, and their *per capita* impacts, even in early invasion stages and, whenever possible, prioritise preventive measures. Quantifying *per capita* impacts is possible for example by estimating consumer functional responses (Dick *et al.*, 2014; Faria *et al.*, 2023). At later invasion stages, the *per capita* effects of a species are nevertheless modulated by the numerical response at the population level (Solomon, 1949; Dick *et al.*, 2017). These *per capita* impacts can fluctuate across space and time (Gallardo *et al.*, 2016); hence, management interventions should aim to reduce population size and growth, because abundance dictates the extent and magnitude of impacts (Dick *et al.*, 2017; Ahmed *et al.*, 2022).

## VI. PROPOSED CLASSIFICATION PROTOCOL

After having identified unclear terms and recommended an acceptable, clear, and concise terminology moving forward, we also propose an objective approach to classify different populations of 'non-native' species for scientific discourse.
This is needed because the term ‘invasive’ itself lacks clear and objective boundaries given the complexities of measuring ‘spread’ across varying scales (i.e. local versus regional spread). While both impactful and spreading species are often wrongly referred to as ‘invasive’, and although useful to assist in focusing management resources and a wider discourse, assessments and classification are often bereft of quantitative boundaries and are subjective. Even if value-laden, concern regarding those ‘invasive’ (spreading) species with impacts (cf. those with few impacts) is based on human values and thus is relevant for the distribution of limited management resources. We therefore recommend an alternative quantitative (binomial) assessment we deem unambiguous and ideal to classify populations of non-native species. The DOSI scheme is based on four main components that the current lexicon captures: (i) DISPERSAL mechanism, defining how a population arrived at a new locality; (ii) ORIGIN, defining the origin (native region) of a species; (iii) STATUS, describing if the population is expanding,

stationary, or shrinking (either in terms of abundance or range) to describe ‘invasiveness’; and (iv) IMPACT, defining the real or perceived impact of the population as harmful or benign and which can be split into: (i) economic (defined as alteration to the financial budget of a geographic region via loss of resources caused by non-native species or from expenditure allocated for management of non-native species), (ii) ecological (defined as alteration to ecological interactions shaped via pre-industrial – non-anthropogenic – evolution, which can include biodiversity loss, ecosystem alteration, predation and disease spread, competition, hybridisation, etc.), (iii) cultural (defined as changes in landscape and heritage, impact on traditional practices, recreational activities, etc.), or (iv) health (defined as consequences from the spread of pathogens or parasites that cause diseases) (Fig. 4).

On the far right in Fig. 4, we provide the dependencies for each component, including how we should define ‘here’ and how we assess ‘status’ and ‘impact’, drawing inspiration from the IUCN Red List of Threatened Species (IUCN, 2023).

<figure><img src="image_6.png" /><figcaption>**Fig. 4.** Flow diagram for the proposed classification scheme for species/populations moving into a novel environment. A species' DISPERSAL mechanism can be assisted from its place of origin either deliberately (Daᵢ) or accidentally (Daᵢᵢ), or it can migrate independently of direct human intervention (Dbᵢ) or by being facilitated (Dbᵢᵢ) by exploiting a human-driven change to the environment (e.g. canals). The ORIGIN of a species that has its distribution shifted according to the mechanisms described under DISPERSAL can either be allochthonous (Oa) (not from 'here', where the definition of 'here' depends on the spatial scale of interest), or autochthonous (Ob) (from 'here', as in the case of local species moving within the region of focus). The definition of allochthonous or autochthonous can also depend on how much time has elapsed since the species arrived (e.g. events in geological time, ancient introductions, etc.). STATUS refers to the state of the population(s) of the species, defined either/both in terms of abundance or/and range size (expanding, static, or shrinking) – these assessments depend on the time that the species has been present, how much measurement effort has been applied to assess population change, and whether interventions (if any) have been effective. The IMPACT category assesses whether the species causes harm to one or more sectors (economy, ecology, culture, health – such an assessment can cover a gradient from little to extensive harm), or if it is benign (no effect) – this assessment also depends on the time since appearance, measurement effort to investigate impact, and any possible benefits along a temporal or stakeholder gradient that modify harm intensity. While we acknowledge that impacts can also be ‘beneficial’, negative impacts (e.g. by damaging local ecology) outweigh those perceived as positive (e.g. monetary gain) in magnitude and ecological consequences, and are therefore not considered in the context of classifying populations of species in this scheme.</figcaption></figure>
For instance, consider the European mink *Mustela lutreola*, listed as 'Critically Endangered' on the IUCN Red List. The decline in its population is due primarily to habitat loss and competition with the non-native American mink *Neogale vison*. We provide a few examples based on our proposed classification protocol. Example 1 is a species that is deliberately introduced into a new country, its population expands both in abundance and range, resulting in economic and ecological harm. In our scheme, its classification would be **DaᵢOaSaᵢ,iiIaᵢ,ii**. Example 2 is a species that is accidentally transported by humans from one part of its range to another. Although it remains static without an increase in range or abundance, it causes cultural harm locally: it is classified as **DaᵢObSbIaᵢ,iii**. Example 3 is a species that establishes itself in a new range following a human modification to its environment (e.g. building a canal connecting two previously isolated bodies of water), subsequently increasing its range and causing ecological problems: it is classified as **DbᵢOaSaᵢIaᵢ**.

To facilitate analyses of the drivers of different states and classifications, this descriptive classification scheme can be illustrated using a binomial matrix, wherein each component and subcomponent are depicted as columns, and species/ populations as rows. We provide an example in Table S2. This classification scheme avoids the use of terminology with a negative connotation and focuses on objective categorisations based on scientific and empirical grounds, while also considering impact, which can be value-laden but relevant for prioritising management. The scheme acknowledges that categorisations vary across time, space, and measurement intensity. Consequently, politically charged terms like 'invasive' or colonial terms such as 'non-indigenous', 'naturalised', or 'colonised' can be circumvented. While we recognise that this classification scheme might not replace common language, it would promote objectivity and consensus among invasion scientists, particularly in the peer-reviewed literature.

Some countries, especially low- and middle-income nations, often have insufficient data covering all four proposed components that are necessary for classifying non-native populations. This difficulty also applies to some taxa, such as fungi and phytoplankton for which many biogeographic and taxonomic uncertainties persist. Nonetheless, we anticipate that our protocol will identify the types of information required. This could in turn enable such nations to prioritise resources towards the generation of this indispensable information for non-native species management.

## VII. CONCLUSIONS

(1) Invasion science is constantly growing and confronting existing terminological inconsistencies, often leading to misunderstanding and confusion that can come at the cost of conservation. Our review sheds light on the issue of lexical inconsistency pervading multiple scientific disciplines, here shown in the case of invasion science, underlining its

potential to obstruct scientific progress, policy design, and effective communication.

(2) We recommend reducing redundancy and propose a unified suite of terms in an attempt to increase the clarity and consistency in invasion science. Any deviation from the proposed terms outlined in Table 4 (i.e. 'non-native' species, 'established non-native' species and 'invasive non-native' species) and their translations in Table S1 should be justified by defining terms appropriately and aligning with the definitions outlined in Table 4. The successful implementation of this consensus will require collaboration among scientists, policy makers, and stakeholders to facilitate interdisciplinary dialogue and exchange of knowledge.

(3) Reaching consensus and implementing measures to achieve consistency in the terminology used across various platforms (i.e. from science to policy, as well as public communication outlets) will not be easy or fast. Efforts by journals, editorial boards, or professional societies and organisations can be an avenue for identifying ways to recognise the challenge and ways to address it. The more simplistic and clearer terminology for broader audiences we propose herein will be helpful to enhance communication and comprehension among scientists, decision-makers, and the public.

(4) We hope that such a unified and standardised language can promote more effective management strategies, better policies, and public engagement in citizen-science initiatives to address the threats of non-native species. By bridging the gap between scientific understanding and practical action, we can improve conservation aiming to protect ecosystems and human health while also minimising economic losses.

## VIII. ACKNOWLEDGEMENTS

We thank C. Capinha, J. Carlton, M. Clavero, F. Essl, T. Heger, B. Lenzner, A. Pauchard, D. Richardson, N. Roura-Pascual, E. Tricarico, and M. Vilà for insightful comments on early drafts, and V. Rudoi for helping with translating to Kazakh language. C. J. A. B. acknowledges funding support from the Australian Research Council Centre for Australian Biodiversity and Heritage (CE170100015). R. N. C. is funded by the Leverhulme Trust (ECF-2021-001). N. I. K. acknowledges funding support from the Russian Science Foundation (projects: No. 22-16-00075, international literature review; No. 21-16-00050, national literature review). G. H. is supported by the Alexander von Humboldt Foundation and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (Capes). J. P. was supported by the Technology Agency of the Czech Republic within the project ‘DivLand’ (No. SS02030018) and the Indonesian Centre for Research on Bioinvasions. F. R. is supported by an individual contract by FCT (CEEC/0482/2020) and by FCT through the strategic projects UIDB/04292/2020 and UIDP/04292 awarded to the Marine and Environmental Sciences Centre and through project LA/P/0069/2020
granted to the Associate Laboratory AR-NET. E.S. and A. Bo. are supported by a Consejo Nacional de Investigaciones Científicas y Técnicas grant (PIP 11220210100507CO). J. F.-A. is supported by the Research Council of Norway, Project No. 302114. A. C. S. F. and E. G.-B. are supported by the Spanish Ministry of Science, Innovation and Universities (MCIN/AEI/10.13039/501100011033) and the European Union (NextGenerationEU/PRTR) through projects PID2019-103936GB-C21, TED2021-129889B-I00, and RED2022-134338-T. We dedicate this paper to Professor Gordon H. Copp, who passed away on 8 July 2023. Gordon was not only a hugely influential scientist, mentor, and friend, but also a notable biologist who made major contributions to the field of aquatic ecology. His later work focused on understanding the mechanisms of biological invasions, assessing their ecological impacts, and developing strategies for their prevention and control. Gordon is best known for his research on the ecological impacts of invasive species and the management of freshwater and marine ecosystems published in more than 200 papers resulting from many national and international research projects and collaborations. On 25 May 2023, Gordon received a Doctor of Science degree for his major contributions to aquatic sciences, which he regarded ‘... a culmination of the scientific component of my life’. Open access publishing facilitated by Jihoceska Univerzita v Cesky Budejovicich, as part of the Wiley - CzechELib agreement.

## IX. DATA ACCESSIBILITY

Data and R code to reproduce trends and word cloud are available from http://github.com/IsmaSA/Invasion-science-terminology.

## X. REFERENCES

AHMED, D. A., HAUBROCK, P. J., CUTHBERT, R. N., BANG, A., SOTO, I., BALZANI, P., TARKAN, A. S., MACÊDO, R. L., CARNEIRO, L., BODEY, T. W., OFICIALDEGUI, F. J., COURTOS, P., KOURANTIDOU, M., ANGULO, E., HERINGER, G., ET AL. (2023). Recent advances in availability and synthesis of the economic costs of biological invasions. *BioScience* **73**, 560–574.

AHMED, D. A., HUDGINS, E. J., CUTHBERT, R. N., KOURANTIDOU, M., DIAGNE, C., HAUBROCK, P. J., LEUNG, B., LIU, C., LEROY, B., PETROVSKII, S., BEIDAS, A. & COURCHAMP, F. (2022). Managing biological invasions: the cost of inaction. *Biological Invasions* **24**, 1927–1946.

AIZEN, M. A., MORALES, C. L., VÁZQUEZ, D. P., GARIBALDI, L. A., SÁEZ, A. & HARDER, L. D. (2014). When mutualism goes bad: density-dependent impacts of introduced bees on plant reproduction. *New Phytologist* **204**, 322–328.

AKSU, S., BASKURT, S., EMIROĞLU, Ö. & TARKAN, A. S. (2021). Establishment and range expansion of non-native fish species facilitated by hot springs: the case study from the upper Sakarya Basin (NW, Turkey). *Oceanological and Hydrobiological Studies* **50**, 247–258.

AMADOR-CRUZ, F., FIGUEROA-RANGEL, B. L., OLVERA-VARGAS, M. & MENDOZA, M. E. (2021). A systematic review on the definition, criteria, indicators, methods and applications behind the Ecological Value term. *Ecological Indicators* **129**, 107856.

AMANO, N., BANKOFF, G., FINDLEY, D. M., BARRETTO-TESORO, G. & ROBERTS, P. (2021). Archaeological and historical insights into the ecological impacts of pre-colonial and colonial introductions into the Philippine Archipelago. *The Holocene* **31**, 313–330.

ANDREU, J., VILÀ, M. & HULME, P. E. (2009). An assessment of stakeholder perceptions and management of noxious alien plants in Spain. *Environmental Management* **43**, 1244–1255.

ANGULO, E., DIAGNE, C., BALLESTEROS-MEJIA, L., ADAMJY, T., AHMED, D. A., AKULOV, E., BANERJEE, A. K., CAPINHA, C., DIA, C. A. K. M., DOBIGNY, G., DUBOSCQ-CARRA, V. G., GOLIVETS, M., HAUBROCK, P. J., HERINGER, G., KIRICHENKO, N., ET AL. (2021). Non-English languages enrich scientific knowledge: the example of economic costs of biological invasions. *Science of the Total Environment* **775**, 14441.

BACHER, S., BLACKBURN, T. M., ESSL, F., GENOVESI, P., HEIKKILÄ, J., JESCHKE, J. M., JONES, G., KELLER, R., KENIS, M., KUEFFER, C., MARTINOU, A. F., NENTWIG, W., PERGL, J., PYŠEK, P., RABITSCH, W., ET AL. (2018). Socio-economic impact classification of alien taxa (SEICAT). *Methods in Ecology and Evolution* **9**, 159–168.

BAKER, H. G. & STEBBINS, G. L. (1965). *The Genetics of Colonizing Species*. Academic Press, New York.

BALZANI, P., DEKONINCK, W., FELDHAAR, H., FREITAG, A., FRIZZI, F., FROUZ, J., MASONI, A., ROBINSON, E., SORVARI, J. & SANTINI, G. (2022). Challenges and a call to action for protecting European red wood ants. *Conservation Biology* **36**, e13959.

BAQUERO, R. A., OFICIALDEGUI, F. J., AYLLÓN, D. & NICOLA, G. G. (2023). The challenge of managing threatened invasive species at a continental scale. *Conservation Biology* **37**, e14165.

BARRETT, L. P., STANTON, L. A. & BENSON-AMRAM, S. (2019). The cognition of 'nuisance' species. *Animal Behaviour* **147**, 167–177.

BARTUMEUS, F., DA LUZ, M. G. E., VISWANATHAN, G. M. & CATALAN, J. (2005). Animal search strategies: a quantitative random-walk analysis. *Ecology* **86**, 3078–3087.

BEEST, M., ELSCHOT, K., OLFF, H. & ETIENNE, R. (2013). Invasion success in a marginal habitat: an experimental test of competitive ability and drought tolerance in *Chromolaena odorata*. *PLoS One* **8**, e62824.

BELLARD, C., MARINO, C. & COURCHAMP, F. (2022). Ranking threats to biodiversity and why it doesn't matter. *Nature Communications* **13**, 2616.

BERG, C. (1877). Enumeración de las plantas europeas que se hallan como silvestres en la provincia de Buenos Aires y en la Patagonia. *Anales de la Sociedad Científica Argentina* **3**, 183–204.

BINGGELI, P. (1994). The misuse of terminology and anthropometric concepts in the description of introduced species. *Bulletin of the British Ecological Society* **25**, 10–13.

BLACKBURN, T. M., PYŠEK, P., BACHER, S., CARLTON, J. T., DUNCAN, R. P., JAROŠÍK, V., WILSON, J. R. U. & RICHARDSON, D. M. (2011). A proposed unified framework for biological invasions. *Trends in Ecology & Evolution* **26**, 333–339.

BLACKMAN, R. C., CONSTABLE, D., HAHN, C., SHEARD, A. M., DURKOTA, J., HÄNFLING, B. & HANDLEY, L. L. (2017). Detection of a new non-native freshwater species by DNA metabarcoding of environmental samples—first record of *Gammarus fossarum* in the UK. *Aquatic Invasions* **12**, 177–189.

BLÁHA, M., WEIPERTH, A., PATOKA, J., SZAJBERT, B., BALOGH, E. R., STASZNY, Á., FERINCZ, Á., LENTE, V., MACIASZEK, R. & KOUBA, A. (2022). The pet trade as a source of non-native decapods: the case of crayfish and shrimps in a thermal waterbody in Hungary. *Environmental Monitoring and Assessment* **194**, 795.

BLUMENTHAL, D. M. (2006). Interactions between resource availability and enemy release in plant invasion. *Ecology Letters* **9**, 887–895.

BORCHERING, J., STAAS, S., KRÜGER, S., ONDRAČKOVÁ, M., SLAPANSKÝ, L. & JURAJPÁ, P. (2011). Non-native Gobiid species in the lower river Rhine (Germany): recent range extensions and densities. *Journal of Applied Ichthyology* **27**, 153–155.

BORTOLUS, A. (2006). The austral cordgrass *Spartina densiflora* Brong.: its taxonomy, biogeography and natural history. *Journal of Biogeography* **33**, 158–168.

BORTOLUS, A. (2012). Running like Alice and losing good ideas: on the quasi-compulsive use of English by non-native English speaking scientists. *Ambio* **41**, 769–772.

BORTOLUS, A., CARLTON, J. T. & SCHWINDT, E. (2015). Reimagining South American coasts: unveiling the hidden invasion history of an iconic ecological engineer. *Diversity and Distributions* **21**, 1267–1283.

BORTOLUS, A. & SCHWINDT, E. (2022). Biological invasions and human dimensions: we still need to work hard on our social perspectives. *Ecologia Austral* **32**, 767–783.

BOUCHER, D. H. (ed.) (1985). *The Biology of Mutualism: Ecology and Evolution*. Oxford University Press, New York.

BRODIE, S., YASUMIBA, K., TOWSEY, M., ROE, P. & SCHWARZKOPF, L. (2021). Acoustic monitoring reveals year-round calling by invasive toads in tropical Australia. *Bioacoustics* **30**, 125–141.

BROWN, J. H. & SAX, D. F. (2004). An essay on some topics concerning invasive species. *Austral Ecology* **29**, 530–536.

BROWN, N. J. (1994). Who abolished corvée labour in Egypt and why? *Past & Present* **144**, 116–137.

BUCHER, E. H. & ARAMBURÚ, R. M. (2014). Land-use changes and monk parakeet expansion in the pampas grasslands of Argentina. *Journal of Biogeography* **41**, 1160–1170.
BULLOCK, O. M., COLÓN AMILL, D., SHULMAN, H. C. & DIXON, G. N. (2019). Jargon as a barrier to effective science communication: evidence from metacognition. *Public Understanding of Science* **28**, 845–853.

CADOTTE, M. W. (2006). Darwin to Elton: early ecology and the problem of invasive species. In *Conceptual Ecology and Invasion Biology: Reciprocal Approaches to Nature* (eds M. W. CADOTTE, S. M. McMAHON and T. FUKAMI), pp. 15–33. Springer Netherlands, Dordrecht.

CALEY, P. & KUHNERT, P. M. (2006). Application and evaluation of classification trees for screening unwanted plants. *Austral Ecology* **31**, 647–655.

CAMBRIDGE ENGLISH DICTIONARY ONLINE (2023a). Invasive (adjective). Cambridge English Dictionary Online. Electronic file available at https://dictionary.cambridge.org/dictionary/english/invasive.

CAMERON, D. (2012). *Verbal hygiene*, Second Edition, p. 268. Routledge, London.

CAREY, M. P., SANDERSON, B. L., BARNAS, K. A. & OLDEN, J. D. (2012). Native invaders-challenges for science, management, policy, and society. *Frontiers in Ecology and the Environment* **10**, 373–381.

CARLON, E. & DOMINONI, D. M. (2023). Reviewing the role of urbanisation in facilitating the introduction and establishment of invasive animal species. *EcoEvoRxiv*. https://doi.org/10.32942/X2D60D.

CARLTON, J. T. (1996). Biological invasions and cryptogenic species. *Ecology* **77**, 1653–1655.

CARLTON, J. T. (2002). Bioinvasion ecology: assessing invasion impact and scale. In *Invasive Aquatic Species of Europe. Distribution, Impacts and Management* (eds E. LEPPAKOSKI, S. GOLLASCH and S. OLENIN), pp. 7–19. Springer Netherlands, Dordrecht.

CARLTON, J. T. (2009). Deep invasion ecology and the assembly of communities in historical time. In *Biological Invasions in Marine Ecosystems: Ecological, Management, and Geographic Perspectives* (eds G. RILLO and J. A. CROOKS), pp. 13–56. Springer Berlin, Heidelberg.

CARVALHO, R. L., RESSENDE, A. F., BARLOW, J., FRANC, F. M., MOURA, M. R., MACIEL, R., ALVES-MARTINS, F., SHUTT, J., NUNES, C. A., ELIAS, F., SILVEIRA, J. M., STEGMANN, L., BACCARO, F. B., JUEN, L., SCHIETTI, J., *et al.* (2023). Pervasive gaps in Amazonian ecological research. *Current Biology* **33**, 3495–3504.

CASSINI, M. H. (2020). A review of the critics of invasion biology. *Biological Reviews* **95**, 1467–1478.

CASTAÑEDA, R. A., CVETANOVSKA, E., HAMELIN, K. M., SIMARD, M. A. & RICCIARDI, A. (2018). Distribution, abundance and condition of an invasive bivalve (*Corbicula fluminea*) along an artificial thermal gradient in the St. Lawrence River. *Aquatic Invasions* **13**, 379–392.

CASTRO, A., RIBEIRO, J., REINO, L. & CAPINHA, C. (2023). Who is reporting non-native species and how? A cross-expert assessment of practices and drivers of non-native biodiversity reporting in species regional listing. *Ecology and Evolution* **13**, e10148.

CATFORD, J. A., BAUMGARTNER, J. B., VESK, P. A., WHITE, M., BUCKLEY, Y. M. & MCCARTHY, M. A. (2016). Disentangling the four demographic dimensions of species invasiveness. *Journal of Ecology* **104**, 1745–1758.

CBD (2020). Zero draft of the post-2020 global biodiversity framework. CBD/WG2020/2/3.

CERCA, J., PURSCHKE, G. & STRUCK, T. H. (2018). Marine connectivity dynamics: clarifying cosmopolitan distributions of marine interstitial invertebrates and the meiofauna paradox. *Marine Biology* **165**, 123.

CERRI, J., MORI, E., TOZZOLI, R., GIGLIOTTI, A., CHIRCO, A. & BERTOLINO, S. (2020). Managing invasive Siberian chipmunks Eutamias sibiricus in Italy: a matter of attitudes and risk of dispersal. *Biological Invasions* **22**, 603–616.

CHOWDHURY, S., DEY, P., JOEL-EDGAR, S., BHATTACHARYA, S., RODRIGUEZ-ESPINDOLA, O., ABADIE, A. & TRUONG, L. (2023). Unlocking the value of artificial intelligence in human resource management through AI capability framework. *Human Resource Management Review* **33**, 100899.

CHRISTY, J. A., KIMPO, A., MARTTALA, V., GADDIS, P. K. & CHRISTY, N. L. (2009). Urbanizing flora of Portland, Oregon, 1806–2008. In *Native Plant Society of Oregon Occasional Paper* (Volume 3), pp. 1–319. Native Plant Society of Oregon, Corvallis, Oregon.

CLAVERO, M., NORES, C., KUBERSKY-PIREDDA, S. & CENTENO-CUADROS, A. (2016). Interdisciplinarity to reconstruct historical introductions: solving the status of cryptogenic crayfish. *Biological Reviews* **91**, 1036–1049.

CLEMENTS, D. R. & DITOMMASO, A. (2011). Climate change and weed adaptation: can evolution of invasive plants lead to greater range expansion than forecasted? *Weed Research* **51**, 227–240.

COLAUTTI, R. I., GRIGOROVICH, I. A. & MACISAAC, H. J. (2006). Propagule pressure: a null model for biological invasions. *Biological Invasions* **8**, 1023–1037.

COLAUTTI, R. I. & MACISAAC, H. J. (2004). A neutral terminology to define 'invasive' species. *Diversity and Distributions* **2**, 135–141.

COLAUTTI, R. I., PARKER, J. D., CADOTTE, M. W., PYŠEK, P., BROWN, C. S., SAX, D. F. & RICHARDSON, D. M. (2014). Quantifying the invasiveness of species. *NeoBiota* **21**, 7–27.

COLAUTTI, R. I. & RICHARDSON, D. M. (2009). Subjectivity and flexibility in invasion terminology: too much of a good thing? *Biological Invasions* **11**, 1225–1229.

COPP, G. H., BIANCO, P. G., BOGUTSKAYA, N. G., ERÖS, T., FALKA, I., FERREIRA, M. T., FOX, M. G., FREYHOF, J., GOZLAN, R. E., GRABOWSKA, J., KOVAC, V., MORENO-AMICH, R., NASEKA, A. M., PENAZ, M., POVZ, M., *et al.* (2005). To be, or not to be, a non-native freshwater fish? *Journal of Applied Ichthyology* **21**, 242–262.

COPP, G. H., VILIZZI, L., TILBURY, H., STEBBING, P., TARKAN, A. S., MIOSSEC, L. & GOULLETQUER, P. (2016). Development of a generic decision-support tool for identifying potentially invasive aquatic taxa: AS-ISK. *Management of Biological Invasions* **7**, 343–350.

COPP, G. H., VILIZZI, L., WEI, H., LI, S., PIRIA, M., AL-FAISAL, A. J., ALMEIDA, D., ATIQUE, U., AL-WAZZAN, Z., BAKIU, R., BAŠIĆ, T., BUI, T. D., CANNING-CLODE, J., CASTRO, N., CHAICHANA, R., *et al.* (2021). Speaking their language – development of a multilingual decision-support tool for communicating invasive species risks to decision makers and stakeholders. *Environmental Modelling & Software* **135**, 104900.

CORLETT, R. T. (2016). Restoration, reintroduction, and rewilding in a changing world. *Trends in Ecology & Evolution* **31**, 453–462.

CORREA, C., LOBOS, G., PASTENES, L. & MÉNDEZ, M. A. (2008). Invasive *Pleurodema thaul* from Robinson Crusoe Island: molecular identification of its geographic origin and comments on the phylogeographic structure of this species in mainland Chile. *The Herpetological Journal* **18**, 77–82.

CORSINI-FORA, M. & ECONOMIDIS, P. S. (2007). Allochthonous and vagrant ichthyofauna in Hellenic marine and estuarine waters. *Mediterranean Marine Science* **8**, 67–90.

COURCHAMP, F., FOURNIER, A., BELLARD, C., BERTELMEISTER, C., BONNAUD, E., JESCHKE, J. M. & RUSSELL, J. C. (2017). Invasion biology: specific problems and possible solutions. *Trends in Ecology & Evolution* **32**, 13–22.

CRAWLEY, M. J., BROWN, S. L., HEARD, M. S. & EDWARDS, R. (1999). Invasion-resistance in experimental grassland communities: species richness or species identity? *Ecology Letters* **2**, 140–148.

CROSBY, A. W. (1986). *Ecological Imperialism: The Biological Expansion of Europe, 900–1900*. Cambridge University Press, London.

CUTHBERT, R., BODEY, T. W., BRISKI, E., CAPELLINI, I., DICK, J. T., KOURANTIDOU, M., RICCIARDI, A. & PINCHEIRA-DONOSO, D. (2023). *Harnessing trait evolution to predict economic costs of biological invasions*. ASSRN 4430070. https://doi.org/10.2139/ssrn.4430070.

CUTHBERT, R. N., DIAGNE, C., HUDGINS, E. J., TURBELIN, A., AHMED, D. A., ALBERT, C., BODEY, T. W., BRISKI, E., ESSL, F., HAUBROCK, P. J., GOZLAN, R. E., KIRICHENKO, N., KOURANTIDOU, M., KRAMER, A. M. & COURCHAMP, F. (2022). Biological invasion costs reveal insufficient proactive management worldwide. *Science of the Total Environment* **819**, 153404.

DALY, E. Z., CHABRERIE, O., MASSOL, F., FACON, B., HESS, M. C., TASIEMSKI, A., GRANDJEAN, F., CHAUVAT, M., VIARD, F., FOREY, E., FOLCHER, L., BUISSON, E., BOIVIN, T., BALTORA-ROSSET, S., ULMER, R., *et al.* (2023). A synthesis of biological invasion hypotheses associated with the introduction–naturalisation–invasion continuum. *Oikos* **2023**, e09645.

DARLING, J. A. & CARLTON, J. T. (2018). A framework for understanding marine cosmopolitanism in the Anthropocene. *Frontiers in Marine Science* **5**, 293.

DARWIN, C. (1859). *On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life*, p. 502. John Murray, London.

DAVIS, M. A. (2006). Invasion biology 1958-2005: the pursuit of science and conservation. In *Conceptual Ecology and Invasion Biology: Reciprocal Approaches to Nature* (eds M. W. CADOTTE, S. M. McMAHON and T. FUKAMI), pp. 35–64. Springer Netherlands, Dordrecht.

DAVIS, M. A. (2009). *Invasion Biology*. Oxford University Press, Oxford.

DAVIS, M. A. & THOMPSON, K. (2000). Eight ways to be a colonizer; two ways to be an invader: a proposed nomenclature scheme for invasion ecology. *Bulletin of the Ecological Society of America* **81**, 226–230.

DE CANDOLLE, A. P. (1855). *Géographie Botanique Raisonné*, Edition (Volume 2). V. Masson, Paris.

DE MEESTER, L., LOUETTE, G., DUVIVIER, C., VAN DAMME, C. & MICHELS, E. (2007). Genetic composition of resident populations influences establishment success of immigrant species. *Oecologia* **153**, 431–440.

DGEBAUDZE, Y. Y. (2014). Invasions of alien species in Holarctic: some results and perspective of investigations. *Russian Journal of Biological Invasions* **1**, 2–8.

DIAGNE, C., LEROY, B., VAISSIÈRE, A.-C., GOZLAN, R. E., ROIZ, D., JARÍC, I., SALLES, J.-M., BRADSHAW, C. J. A. & COURCHAMP, F. (2021). High and rising economic costs of biological invasions worldwide. *Nature* **592**, 571–576.

DICK, J. T., ALEXANDER, M. E., JESCHKE, J. M., RICCIARDI, A., MACISAAC, H. J., ROBINSON, T. B., KUMSCHICK, S., WEYL, O. L., F., DUNN, A. M., HATCHER, M. J., PATERSON, R. A., FARNSWORTH, K. D. & RICHARDSON, D. M. (2014). Advancing impact prediction and hypothesis testing in invasion ecology using a comparative functional response approach. *Biological Invasions* **16**, 735–753.
DICK, J. T., LAVERTY, C., LENNON, J. J., BARRIOS-O'NEILL, D., MENSINK, P. J., BRITTON, R. J., MÉDOC, V., BOETS, P., ALEXANDER, M. E., TAYLOR, N. G., DUNN, A. M., HATCHER, M. J., ROSEWARNE, P. J., CROOKES, S., MACISAAC, H. J., ET AL. (2017). Invader relative impact potential: a new metric to understand and predict the ecological impacts of existing, emerging and future invasive alien species. *Journal of Applied Ecology* **54**, 1259-1267.

DORIA, C. R. D. C., AGUDELO, E., AKAMA, A., BARROS, B., BONFIM, M., CARNEIRO, L., BRIGILA-FERREIRA, S. R., NOBRE CARVALHO, L., BONILLA-CASTILLO, C. A., CHARVET, P., DOS SANTOS CATÂNEO, D. T. B., DA SILVA, H. P., GARCIA-DÁVILA, C. R., DOS ANJOS, H. D. B., DUPONCHELLE, F., ET AL. (2021). The silent threat of non-native fish in the amazon: ANNF database and review. *Frontiers in Ecology and Evolution* **9**, 646702.

DUNN, M., MARZANO, M., FORSTER, J. & GILL, R. M. (2018). Public attitudes towards 'pest' management: perceptions on squirrel management strategies in the UK. *Biological Conservation* **222**, 52–63.

ECHEVERRÍA, C., COOMES, D., SALAS, J., REY-BENAYAS, J. M., LARA, A. & NEWTON, A. (2006). Rapid deforestation and fragmentation of Chilean temperate forests. *Biological Conservation* **130**, 481–494.

ECKSTEIN, R. L., RUCH, D., OTTE, A. & DONATH, T. W. (2012). Invasibility of a nutrient-poor pasture through resident and non-resident herbs is controlled by litter, gap size and propagule pressure. *PLoS One* **7**, e41887.

ELLENDER, B. R. & WEYL, O. L. (2014). A review of current knowledge, risk and ecological impacts associated with non-native freshwater fish introductions in South Africa. *Aquatic Invasions* **9**, 117-132.

ELLWOOD, E. R., PAULY, G. B., AHN, J., GOLEMBIEWSKI, K., HIGGINS, L. M., ORDEÑANA, M. A. & VON KONRAT, M. (2023). Citizen science needs a name change. *Trends in Ecology & Evolution* **38**, 485-489.

ELTON, C. (1942). *Voles, Mice and Lemmings. Problems in Population Dynamics*. Clarendon Press, Oxford.

ELTON, C. S. (2020). *The Ecology of Invasions by Animals and Plants*. Second Edition, p. 181. Springer, Switzerland.

EPANCHIN-NIEL, R. S. & HASTINGS, A. (2010). Controlling established invaders: integrating economics and spread dynamics to determine optimal management. *Ecology Letters* **13**, 528-541.

ESSL, F., BACHER, S., GENOVESI, P., HULME, P. E., JESCHKE, J. M., KATSANEVAKIS, S., KOWARIK, I., KÜHN, I., PYŠEK, P., RABITSCH, W., SCHINDLER, S., VAN KLEUNEN, M., VILÀ, M., WILSON, J. R. U. & RICHARDSON, D. M. (2018). Which taxa are alien? Criteria, applications, and uncertainties. *BioScience* **68**, 496-509.

ESSL, F., DULLINGER, S., GENOVESI, P., HULME, P. E., JESCHKE, J. M., KATSANEVAKIS, S., KÜHN, I., LENZNER, B., PAUCHARD, A., PYŠEK, P., RABITSCH, W., RICHARDSON, D. M., SEEBENS, H., VAN KLEUNEN, M., VAN DER PUTTEN, W. H., ET AL. (2019). A conceptual framework for range-expanding species that track human-induced environmental change. *BioScience* **69**, 908-919.

ESSL, F., DULLINGER, S., GENOVESI, P., HULME, P. E., JESCHKE, J. M., KATSANEVAKIS, S., KÜHN, I., LENZNER, B., PAUCHARD, A., PYŠEK, P., RABITSCH, W., RICHARDSON, D. M., SEEBENS, H., VAN KLEUNEN, M., VAN DER PUTTEN, W. H., ET AL. (2020). Distinct biogeographic phenomena require a specific terminology: A reply to Wilson and Sagoff. *BioScience* **70**, 112-114.

ESSL, F., DULLINGER, S., RABITSCH, W., HULME, P. E., HÜLBER, K., JAROŠÍK, V., KLEINBAUER, I., KRAUSMANN, F., KÜHN, I., NENTWIG, W., VILÀ, M., GENOVESI, P., GHERARDI, F., DESPREZ-LOUSTAU, M.-L., ROQUES, A. & PYŠEK, P. (2011). Socioeconomic legacy yields an invasion debt. *Proceedings of the National Academy of Sciences* **108**, 203-207.

ESSL, F., GLASER, M. & SCHERTLER, A. (2021a). New and old invaders in forests in eastern Austria: the role of species attributes and invasion history. *Flora* **283**, 151922.

ESSL, F., PYŠEK, P. & RICHARDSON, D. M. (2021b). Neonatives and translocated species: different terms are needed for different species categories in conservation policies. *NeoBiota* **68**, 101-104.

EVANS, J., ARNDT, E. & SCHEMBRI, P. J. (2020). Atlantic fishes in the Mediterranean: using biological traits to assess the origin of newcomer fishes. *Marine Ecology Progress Series* **643**, 133-143.

FACHINELLO, M. C., ROMERO, J. H. C. & DE CASTRO, W. A. C. (2022). Defining invasive species and demonstrating impacts of biological invasions: a scientometric analysis of studies on invasive alien plants in Brazil over the past 20 years. *NeoBiota* **76**, 13-24.

FALK-PETERSEN, J., BÖHN, T. & SANDLUND, O. T. (2006). On the numerous concepts in invasion biology. *Biological Invasions* **8**, 1409-1424.

FARIA, L., CUTHBERT, R. N., DICKEY, J. W., JESCHKE, J. M., RICCIARDI, A., DICK, J. T. & VITULE, J. R. (2023). The rise of the functional response in invasion science: a systematic review. *NeoBiota* **85**, 43-79.

FARIA, L., DE CARVALHO, B. M., CARNEIRO, L., MIILLER, N. O. R., PEDROSO, C. R., OCCHI, T. V. T., TONDELLA, L. H. & VITULE, J. R. S. (2022). Invasive species policy in Brazil: a review and critical analysis. *Environmental Conservation* **50**, 67-72.

FAROUK, M. (2019). La corvée lors du creusement de l'isthme: Guerre des discours et représentation romanesque. *Sociétés & Représentations* **48**, 143-155.

FLOERL, O., INGLIS, G. J., DEY, K. & SMITH, A. (2009). The importance of transport hubs in stepping-stone invasions. *Journal of Applied Ecology* **46**, 37-45.

FLORENCIO, M., LOBO, J. M. & BINI, L. M. (2019). Biases in global effects of exotic species on local invertebrates: a systematic review. *Biological Invasions* **21**, 3043-3061.

FORGINE, L., BACHER, S. & VIMERCATI, G. (2022). Are species more harmful in their native, neonative or alien range? Insights from a global analysis of bark beetles. *Diversity and Distributions* **28**, 1832-1849.

FRANK, J. H. & MCCOY, E. D. (1990). Endemics and epidemics of shibboleths and other things causing chaos. *Florida Entomologist* **73**, 1-8.

GAGO, J., ANASTÁCIO, P., GKENAS, C., BANHA, F. & RIBEIRO, F. (2016). Spatial distribution patterns of the non-native European catfish, *Silurus glanis*, from multiple online sources–a case study for the River Tagus (Iberian Peninsula). *Fisheries Management and Ecology* **23**, 503-509.

GALIL, B. S. (2006). The marine caravan–the Suez Canal and the Erythrean invasion. In *Bridging Divides: Maritime Canals as Invasion Corridors* (eds S. GOLLASCH, B. S. GALIL & A. N. COHEN), pp. 207–300. Springer, Netherlands, Dordrecht.

GALIL, B. S., MIENIS, H. K., HOFFMAN, R. & GOREN, M. (2021). Non-indigenous species along the Israeli Mediterranean coast: tally, policy, outlook. *Hydrobiologia* **848**, 2011-2029.

GALLARDO, B., CLAVERO, M., SÁNCHEZ, M. I. & VILÀ, M. (2016). Global ecological impacts of invasive species in aquatic ecosystems. *Global Change Biology* **22**, 151-163.

GARCÍA-DÍAZ, P., CASSEY, P., NORBURY, G., LAMBIN, X., MONTTI, L., PIZARRO, J. C., POWELL, P. A., BURSLEM, D. F. R. P., CAVA, M., DAMASCENO, G., FASOLA, L., FIDELIS, A., HUERTA, M. F., LANGDON, B., LINARDAKI, E., ET AL. (2021). Management policies for invasive alien species: addressing the impacts rather than the species. *BioScience* **71**, 174-185.

GILROY, J. J., AVERY, J. D. & LOCKWOOD, J. L. (2017). Seeking international agreement on what it means to be ‘native’. *Conservation Letters* **10**, 238-247.

GKENAS, C., MARTELO, J., RIBEIRO, D., GAGO, J., DIAS, D., SANTOS, G. & RIBEIRO, F. (2024). Westwards expansion of the European catfish *Silurus glanis* in the Douro River (Portugal). *Linnetica* **43**, 1-8.

GOLEBIE, E. J., VAN RIPER, C. J., ARLINGHAUS, R., GADDY, M., JANG, S., KOCHSLI, S., LU, Y., OLDEN, J. D., STEDMAN, R. & SUSKI, C. (2022). Words matter: a systematic review of communication in non-native aquatic species literature. *NeoBiota* **74**, 1-28.

GONZÁLEZ-MORENO, P., LAZZARO, L., VILÀ, M., PREDA, C., ADRIAENS, T., BACHER, S., BRUNDU, G., COPP, G. H., ESSL, F., GARCÍA-BERTHOU, E., KATSANEVAKIS, S., MOEN, T. L., LUCY, F. E., NENTWIG, W., ROY, H. E., ET AL. (2019). Consistency of impact assessment protocols for non-native species. *NeoBiota* **44**, 1-25.

GORMLEY, A. M., FORSYTH, D. M., GRIFFIOEN, P., LINDEMAN, M., RAMSEY, D. S., SCROGGIE, M. P. & WOODFORD, L. (2011). Using presence-only and presence-absence data to estimate the current and potential distributions of established invasive species. *Journal of Applied Ecology* **48**, 25-34.

GOUIN, N., GRANDJEAN, F., BOUCHON, D., REYNOLDS, J. D. & SOUTY-GROSSET, C. (2001). Population genetic structure of the endangered freshwater crayfish *Austropotamobius pallipes*, assessed using RAPD markers. *Heredity* **87**, 80-87.

GREEN, R. E. (1997). The influence of numbers released on the outcome of attempts to introduce exotic bird species to New Zealand. *Journal of Animal Ecology* **66**, 25-35.

GROOM, Q., DESMET, P., REYSERHOVE, L., ADRIAENS, T., OLDONI, D., VANDERHOEVEN, S., BASKAUF, S. J., CHAPMAN, A., MCGEOCH, M., WALLS, R., WIECZOREK, J., WILSON, J. R. U., ZEWOGLIO, P. F. F. & SIMPSON, A. (2019). Improving Darwin Core for research and management of alien species. *Biodiversity Information Science and Standards* **3**, e38084.

GROSS, K. C. & PHARR, D. M. (1982). A potential pathway for galactose metabolism in *Cucumis sativus* L., a stachyose transporting species. *Plant Physiology* **69**, 117-121.

GUERISOLI, M. M., SCHIAFFINI, M. I., TETA, P., VALENZUELA, A. E. J., MIROL, P., DEFOSSE, G. E., GODOY, M. M., KRIEGER, P., WHITTINGTON, T., AGOSTINI, M. G., ANDERSON, C. B., ANELLO, M., APRILE, G., AQUINO, J. E., ARGOITTA, A., ET AL. (2023). Reflexiones acerca del «reasilvestramiento» en la Argentina. *Mastozoologia Neotropical* **30**, e0946.

GUO, Q. & RICKLEFS, R. E. (2010). Domestic exotics and the perception of invasibility. *Diversity and Distributions* **16**, 1034-1039.

GUREVITCH, J., FOX, G. A., WARDLE, G. M. & INDERJIT, D. T. (2011). Emergent insights from the synthesis of conceptual frameworks for biological invasions. *Ecology Letters* **14**, 407-418.

HÄLLFORS, M. H., VAARA, E. M., HYVÄRINEN, M., OKSANEN, M., SCHULMAN, L. E., SIPI, H. & LEHVÄVIRTA, S. (2014). Coming to terms with the concept of moving species threatened by climate change - a systematic review of the terminology and definitions. *PLoS One* **9**, e102979.

HARGREAVES, A. L., SAMIS, K. E. & ECKERT, C. G. (2014). Are species' range limits simply niche limits writ large? A review of transplant experiments beyond the range. *The American Naturalist* **183**, 157-173.

HASTINGS, A. (1996). Models of spatial spread: a synthesis. *Biological Conservation* **78**, 143-148.
HAUBROCK, P. J., AHMED, D. A., CUTHBERT, R. N., STUBBINGTON, R., DOMISCH, S., MARQUEZ, J. R. G., BEIDAS, A., AMATULLI, G., KIESEL, J., SHEN, L. Q., SOTO, I., ANGELER, D. G., BONADA, N., CAÑEDO-ARGÜELLES, M., CSABAI, Z., ET AL. (2022). Invasion impacts and dynamics of a European-wide introduced species. *Global Change Biology* **28**, 4620–4632.

HAUBROCK, P. J., CUTHBERT, R. N., BALZANI, P., BRISKI, E., CANO-BARBACIL, C., DE SANTIS, V., HUDGINS, E. J., KOUBA, A., MACÉDO, R. L., KOURANTIDOU, M., RENAULT, D., RICO-SÁNCHEZ, A. E., SOTO, I., TOUTAIN, M., TRICARICO, E. & TARKAN, A. S. (2024). Discrepancies between non-native and invasive species classifications. *Biological Invasions* **26**, 371–384.

HAUBROCK, P. J., KULESSA, A., MACÉDO, R. L. & TARKAN, A. S. (2023). Exploring the distribution of the non-native *Umbra pygmaea* across European freshwater ecoregions through climatic suitability and locally consumed diet. *Aquatic Sciences* **85**, 90.

HAWKINS, C. L., BACHER, S., ESSL, F., HULME, P. E., JESCHKE, J. M., KÜHN, I., KUMSCHICK, S., NENTWIG, W., PERGL, J., PYŠEK, P., RABITSCH, W., RICHARDSON, D. M., VILÄ, M., WILSON, J. R. U., GENOVESI, P. & BLACKBURN, T. M. (2015). Framework and guidelines for implementing the proposed IUCN Environmental Impact Classification for Alien Taxa (EICAT). *Diversity and Distributions* **21**, 1360–1363.

HEGER, T., JESCHKE, J. M. & KOLLMANN, J. (2021). Some reflections on current invasion science and perspectives for an exciting future. *NeoBiota* **68**, 79–100.

HEGER, T., SAUL, W. C. & TREPL, L. (2013). What biological invasions 'are' is a matter of perspective. *Journal for Nature Conservation* **21**, 93–96.

HELMREICH, S. (2005). How scientists think; about 'natives', for example. A problem of taxonomy among biologists of alien species in Hawaii. *Journal of the Royal Anthropological Institute* **11**, 107–128.

HENGEVELD, R. (1992). Potential and limitations of predicting invasion rates. *Florida Entomologist* **75**, 60–72.

HERRANDO-PÉREZ, S., DELEAN, S., BROOK, B. W. & BRADSHAW, C. J. A. (2012). Density dependence: an ecological Tower of Bad. *Oecologia* **170**, 585–603.

HIRST, R. (2003). Scientific jargon, good and bad. *Journal of Technical Writing and Communication* **33**, 201–229.

HODGES, K. E. (2008). Defining the problem: terminology and progress in ecology. *Frontiers in Ecology and the Environment* **6**, 35–42.

HOLZAPFEL, A. M. & VINEBROOKE, R. D. (2005). Environmental warming increases invasion potential of alpine lake communities by imported species. *Global Change Biology* **11**, 2009–2015.

HOWARD, B. R., BARRIOS-O'NEILL, D., ALEXANDER, M. E., DICK, J. T., THERRIAULT, T. W., ROBINSON, T. B. & CÔTÉ, I. M. (2018). Functional responses of a cosmopolitan invader demonstrate intraspecific variability in consumer-resource dynamics. *Peet J* **6**, c5634.

HUI, C. & RICHARDSON, D. M. (2017). *Invasion Dynamics*. Oxford University Press, Oxford.

HUI, C. & RICHARDSON, D. M. (2019). How to invade an ecological network. *Trends in Ecology & Evolution* **34**, 121–131.

ANNONE, B. V. III, CARNEVALE, S., MAIN, M. B., HILL, J. E., MCCONNELL, J. B., JOHNSON, S. A., ENLOE, S. F., ANDREU, M., BELL, E. C., CUDA, J. P. & BAKER, S. M. (2020). Invasive species terminology: standardizing for stakeholder education. *The Journal of Extension* **58**, v58-3a3.

IBANEZ, I., CLARK, J. S. & DIETZE, M. C. (2008). Evaluating the sources of potential migrant species: implications under climate change. *Ecological Applications* **18**, 1664–1678.

IUCN (2023). *The IUCN Red List of Threatened Species*. Version 2023-1. iucnredlist.org. Accessed on 19 July 2023.

IUELL, B. (2002). Prevention of unwanted species immigrating to islands on strait crossings. In *Proceedings of the International Conference on Ecology and Transportation*. September 24–28, Burlington, p. 2001.

JAMES, S. W. & HENDRIX, P. F. (2004). Invasion of exotic earthworms into North America and other regions. *Earthworm Ecology* **41**, 75–88.

JESCHKE, J. & HEGER, T. (eds) (2018). *Invasion Biology: Hypotheses and Evidence*, p. 188. CABI, Wallingford.

JESCHKE, J. M., BACHER, S., BLACKBURN, T. M., DICK, J. T., ESSL, F., EVANS, T., GAERTNER, M., HULME, P. E., KÜHN, I., MRUGALA, A., PERGL, J., PYŠEK, P., RABITSCH, W., RICCIARDI, A., RICHARDSON, D. M., ET AL. (2014). Defining the impact of non-native species. *Conservation Biology* **28**, 1188–1194.

KAMADA, S., MURAKAMI, T. & MASUDA, R. (2013). Multiple origins of the Japanese marten *Martes melampus* introduced into Hokkaido Island, Japan, revealed by microsatellite analysis. *Mammal Study* **38**, 261–267.

KAPITZA, K., ZIMMERMANN, H., MARTÍN-LÓPEZ, B. & VON WEHRDEN, H. (2019). Research on the social perception of invasive species: A systematic literature review. *NeoBiota* **43**, 47–68.

KELLER, R. P., GEIST, J., JESCHKE, J. M. & KÜHN, I. (2011). Invasive species in Europe: ecology, status, and policy. *Environmental Sciences Europe* **23**, 1–17.

KING, R. T. (1942). Is it wise policy to introduce exotic game birds? *Audubon Magazine* **44**, 136–145.

KIRK, D. A., PARK, A. C., SMITH, A. C., HOWES, B. J., PROUSE, B. K., KYSNA, N. G., FAIRHURST, E. N. & PRIOR, K. A. (2018). Our use, misuse, and abandonment of a concept: Whither habitat? *Ecology and Evolution* **8**, 4197–4208.

KLIMASZEWSKI, J., BOURDON, C. & PELLETIER, G. (2013). *Synopsis of Adventive Species of Coleoptera (Insecta) Recorded from Canada. Part 2: Staphylinidae*, p. 360. Pensoft Publishers, Sophia and Moscow.

KLOTZ, P. (1999). Politeness and political correctness: ideological implications. *Pragmatics. Quarterly Publication of the International Pragmatics Association* **9**, 155–161.

KLOTZ, W., MIESEN, F. W., HÜLLEN, S. & HERDER, F. (2013). Two Asian fresh water shrimp species found in a thermally polluted stream system in North Rhine-Westphalia, Germany. *Aquatic Invasions* **8**, 333–339.

KOLAR, C. S. & LODGE, D. M. (2001). Progress in invasion biology: predicting invaders. *Trends in Ecology & Evolution* **16**, 199–204.

KOURANTIDOU, M., HAUBROCK, P. J., CUTHBERT, R. N., BODEY, T. W., LENZNER, B., GOZLAN, R. E., NUÑEZ, M. A., SALLES, J.-M., DIAGNE, C. & COURCHAMP, F. (2022). Invasive alien species as simultaneous benefits and burdens: trends, stakeholder perceptions and management. *Biological Invasions* **24**, 1905–1926.

KUEFFER, C. & DAEHLER, C. C. (2009). A habitat-classification framework and typology for understanding, valuing, and managing invasive species impacts. In *Management of Invasive Weeds* (eds C. KUEFFER, C. C. DAEHLER & S. INDERJIT), pp. 77–101. Springer, Dordrecht.

KÜHN, I., WOLF, J. & SCHNEIDER, A. (2017). Is there an urban effect in alien plant invasions? *Biological Invasions* **19**, 3505–3513.

LA SORTE, F. A. & PYŠEK, P. (2009). Extra-regional residence time as a correlate of plant invasiveness: European archaeophytes in North America. *Ecology* **90**, 2589–2597.

LAMBERT, A. M., DUDLEY, T. L. & SALTONSTALL, K. (2010). Ecology and impacts of the large-statured invasive grasses *Arundo donax* and *Phragmites australis* in North America. *Invasive Plant Science and Management* **3**, 489–494.

LARSON, B. M. (2005). The war of the roses: demilitarizing invasion biology. *Frontiers in Ecology and the Environment* **3**, 495–500.

LARSON, B. M. (2007). An alien approach to invasive species: objectivity and society in invasion biology. *Biological Invasions* **9**, 947–956.

LATOMBE, G., CANAVAN, S., HIRSCH, H., HUI, C., KUMSCHICK, S., NSIKANI, M. M., POTGIETER, L. J., ROBINSON, T. B., SAUL, W.-C., TURNER, S. C., WILSON, J. R. U., YANNELLI, F. A. & RICHARDSON, D. M. (2019). A four-component classification of uncertainties in biological invasions: implications for management. *Ecosphere* **10**, e02669.

LAUFER, G., GOBEL, N., KACEVAS, N. & LADO, I. (2023). American bullfrog (*Lithobates caatesbeianus*) distribution, impact on native amphibians and management priorities in San Carlos, Uruguay. *Knowledge & Management of Aquatic Ecosystems* **42**, 20.

LAWRENCE, E. (2000). *Henderson's Dictionary of Biological Terms*, p. 719. Prentice Hall, Harlow.

LEMOINE, R. T. & SVENNING, J. C. (2022). Nativeness is not binary—a graduated terminology for native and non-native species in the Anthropocene. *Restoration Ecology* **30**, e13636.

LENOIR, J., BERTRAND, R., COMTE, L., BOURGEAUD, L., HATTAB, T., MURIENNE, J. & GRENOUILLET, G. (2020). Species better track climate warming in the oceans than on land. *Nature Ecology & Evolution* **4**, 1044–1059.

LENZNER, B., LATOMBE, G., SCHERTLER, A., SEEBENS, H., YANG, Q., WINTER, M., WEIGELT, P., VAN KLEUNEN, M., PYŠEK, P., PERGL, J., KREFT, H., DAWSON, W., DULLINGER, S. & ESSL, F. (2022). Naturalized alien floras still carry the legacy of European colonialism. *Nature Ecology and Evolution* **6**, 1723–1732.

LEOPOLD, A. (1949). *A Sand County Almanac and Sketches Here and there*. Oxford University Press, New York.

LEPCZYK, C. A. (2022). Time to retire 'alien' from the invasion ecology lexicon. *Frontiers in Ecology and the Environment* **20**, 447.

LEUNG, B., LODGE, D. M., FINNOFF, D., SHOGREN, J. F., LEWIS, M. A. & LAMBERTI, G. (2002). An ounce of prevention or a pound of cure: bioeconomic risk analysis of invasive species. *Proceedings of the Royal Society B* **269**, 2407–2413.

LEWIS, M. A., PETROVSKII, S. V. & POTTS, J. R. (2016). *The Mathematics behind Biological Invasions, Interdisciplinary Applied Mathematics*. Springer International Publishing, Cham.

LIEBOLD, A. M., BROCKERHOFF, E. G., KALISZ, S., NUÑEZ, M. A., WARDLE, D. A. & WINGFIELD, M. J. (2017). Biological invasions in forest ecosystems. *Biological Invasions* **19**, 3437–3458.

LIEURANCE, D., KUEBBING, S., MCCARY, M. A. & NUÑEZ, M. A. (2022). Words matter: how to increase gender and LGBTQIA+ inclusivity at biological invasions. *Biological Invasions* **24**, 341–344.

LIU, X. & LI, Y. (2009). Aquaculture enclosures relate to the establishment of feral populations of introduced species. *PLoS One* **4**, e6199.

LOCKWOOD, J. L., CASSEY, P. & BLACKBURN, T. (2005). The role of propagule pressure in explaining species invasions. *Trends in Ecology & Evolution* **20**, 223–228.

LOCKWOOD, J. L., HOOPES, M. F. & MARCHETTI, M. P. (2013). *Invasion Biology*. John Wiley & Sons, New York.
LONSDALE, W. M. (1999). Global patterns of plant invasions and the concept of invasibility. *Ecology* **80**, 1522–1536.

LUIZ, O. J., FLOETER, S. R., ROCHA, L. A. & FERREIRA, C. E. (2013). Perspectives for the lionfish invasion in the South Atlantic: are Brazilian reefs protected by the currents? *Marine Ecology Progress Series* **485**, 1–7.

MACÉDO, R. L., ELMOOR-LOUREIRO, L. M., SOUSA, F. D. R., RIETZLER, A. C., PERBICHE-NEVES, G. & ROCHA, O. (2023). From pioneers to modern-day taxonomists: the good, the bad, and the idiosyncrasies in choosing species epithets of rotifers and microcrustaceans. *Hydrobiologia* **850**, 4271–4282.

MACISAAC, H. J., TEDLA, R. A. & RICCIARDI, A. (2011). Patterns and rate of growth of studies in invasion ecology. In *Fifty Years of Invasion Ecology: The Legacy of Charles Elton* (ed. D. M. RICHARDSON), pp. 51–60. Wiley-Blackwell, Oxford.

MADSEN, D. H. (1937). Protection of native fishes in the national parks. *Transactions of the American Fisheries Society* **66**, 395–397.

MANCHESTER, S. J. & BULLOCK, J. M. (2000). The impacts of non-native species on UK biodiversity and the effectiveness of control. *Journal of Applied Ecology* **37**, 845–864.

MARTÍNEZ, A. & MAMMOLA, S. (2021). Specialized terminology reduces the number of citations of scientific papers. *Proceedings of the Royal Society B* **288**, 20202581.

MASLYAKOV, V. Y. & IZHEVSKY, S. S. (2011). *Alien Phytophagous Insects Invasions in the European Part of Russia*, p. 272. IGRAS, Moscow [in Russian].

MATSUZAKI, S. S., SASAKI, T. & AKASAKA, M. (2013). Consequences of the introduction of exotic and translocated species and future extirpations on the functional diversity of freshwater fish assemblages. *Global Ecology and Biogeography* **22**, 1071–1082.

MCGLYNN, T. P. (1999). The worldwide transfer of ants: geographical distribution and ecological invasions. *Journal of Biogeography* **26**, 535–548.

MCNEILL, J. R. (2003). Europe's place in the global history of biological exchange. *Landscape Research* **28**, 33–39.

METZGER, N. & ZARE, R. N. (1999). Interdisciplinary research: from belief to reality. *Science* **283**, 642–643.

MONTGOMERY, S. L. (1989). The cult of jargon: reflections on language in science. *Science as Culture* **1**, 42–77.

MORRIS, C. (1992). *Academic Press Dictionary of Science and Technology*, p. 2432. Academic Press, San Diego.

MWANGI, E. & SWALLOW, B. (2008). *Prosopis juliflora* invasion and rural livelihoods in the Lake Baringo area of Kenya. *Conservation and Society* **6**, 130–140.

MYERS, J. H., SIMBERLOFF, D., KURIS, A. M. & CAREY, J. R. (2000). Eradication revisited: dealing with exotic species. *Trends in Ecology & Evolution* **15**, 316–320.

NADEL, H., FRANK, J. H. & KNIGHT, R. J. (1992). Escapees and accomplices: the naturalization of exotic *Ficus* and their associated faunas in Florida. *Florida Entomologist* **75**, 29–38.

NAGY, K. & JOHNSON, P. D. II (eds) (2013). *Trash Animals: How we Live with nature's Filthy, Feral, Invasive, and Unwanted Species*. University of Minnesota Press, Minnesota.

NAYLOR, R. L., WILLIAMS, S. L. & STRONG, D. R. (2001). Aquaculture — a gateway for exotic species. *Science* **294**, 1655–1656.

NELUFULE, T., ROBERTSON, M. P., WILSON, J. R. U. & FAULKNER, K. T. (2022). native-alien populations—an apparent oxymoron that requires specific conservation attention. *NeoBiota* **74**, 57–74.

NELUFULE, T., ROBERTSON, M. P., WILSON, J. R. U. & FAULKNER, K. T. (2023). An inventory of native-alien populations in South Africa. *Scientific Data* **10**, 213.

NUNEZ, M. A., CHIUFFO, M. C., SEEBENS, H., KUEBBING, S., MCCARY, M. A., LIEURANCE, D., ZHANG, B., SIMBERLOFF, D. & MEYERSON, L. A. (2022). Two decades of data reveal that biological invasions needs to increase participation beyond North America, Europe, and Australasia. *Biological Invasions* **24**, 333–340.

OCCHIPINTI-AMBROGI, A. (2021). Biopollution by invasive marine non-indigenous species: a review of potential adverse ecological effects in a changing climate. *International Journal of Environmental Research and Public Health* **18**, 4268.

OCCHIPINTI-AMBROGI, A. & GALIL, B. S. (2004). A uniform terminology on bioinvasions: A chimera or an operating tool? *Marine Pollution Bulletin* **49**, 688–694.

OGG, A. G. & DAWSON, J. H. (1984). Time of emergence of eight weed species. *Weed Science* **32**, 327–335.

OJAVEER, H., GALIL, B. S., CAMPBELL, M. L., CARLTON, J. T., CANNING-CLODE, J., COOK, E. J., DAVIDSON, A. D., HEWITT, C. L., JELMERT, A., MARCHINI, A., MCKENZIE, C. H., MINCHIN, D., OCCHIPINTI-AMBROGI, A., OLELIN, S. & RUIZ, G. (2015). Classification of non-indigenous species based on their impacts: considerations for application in marine management. *PLoS Biology* **13**, e1002130.

OLIVER, W. R. B. (1930). *New Zealand Birds*. A.H. and A.D. Reed, Wellington.

OOSTING, H. J. (1948). *The Study of Plant Communities: An Introduction to Plant Ecology*. Freeman, San Francisco.

ORTIZ-SERRANO, M. & FORERO-LAVERDE, G. (2020). Fake news and talking up the market: the case of the Compagnie universelle du canal interocanéique de Panama in 1888. *Entreprises et Histoire* **101**, 27–43.

ORWELL, G. (1968). Politics and the English Language. In *The Collected Essays, Journalism and Letters of George Orwell Vol IV “In Front of Four Nose” 1945-1950*. Secker and Warburg, London.

OXFORD ENGLISH DICTIONARY ONLINE (2023b). Invasive (adjective). In *Oxford English Dictionary Online*. https://www.oed.com/dictionary/invasive-adj?tab=factsheet#181340.

PACE, P. & SEVERANCE, K. (2016). Migration terminology matters. *Forced Migration Review* **51**, 69–70.

PACKER, J. G., MEYERSON, L. A., SKÁLOVÁ, H., PYŠEK, P. & KUEFFER, C. (2017). Biological flora of the British Isles: *Phragmites australis*. *Journal of Ecology* **105**, 1123–1162.

PADIAL, A. A., AGOSTINHO, Â. A., AZEVEDO-SANTOS, V. M., FREHSE, F. A., LIMA-JUNIOR, D. P., MAGALHAES, A. L., MORMUL, R. P., PELICICE, F. M., BEZERRA, L. A. V., ORSI, M. L., PETRERE-JUNIOR, M. & VITULE, J. R. (2017). The 'tilapia law' encouraging non-native fish threatens Amazonian river basins. *Biodiversity and Conservation* **26**, 243–246.

PADILLA, D. K. & WILLIAMS, S. L. (2004). Beyond ballast water: aquarium and ornamental trades as sources of invasive species in aquatic ecosystems. *Frontiers in Ecology and the Environment* **2**, 131–138.

PASCUAL, U., ADAMS, W. M., DÍAZ, S., LELE, S., MACE, G. M. & TURNHOUT, E. (2021). Biodiversity and the challenge of pluralism. *Nature Sustainability* **4**, 567–572.

PASSERA, L. (2021). Characteristics of Tramp Species. In *Exotic Ants: Biology, Impact, and Control of Introduced Species* (ed. D. F. WILLIAMS), pp. 23–43. CRC Press, Westview.

PEREYRA, P. J. (2020). Rethinking the native range concept. *Conservation Biology* **34**, 373–377.

PEREYRA, P. J., ROSSINI, G. B. & DARRIGRAN, G. (2012). Toxicity of neem's oil, a potential biocide against the invasive mussel *Limnoperna fortunei* (Dunker 1857). *Anais da Academia Brasileira de Ciências* **84**, 1065–1071.

PÉREZ, J. E., ALFONSI, C., NIRCHIO, M. & SALAZAR, S. K. (2008). Bioinvaders: the acquisition of new genetic variation. *Interciencia* **33**, 935–940.

PHELOUNG, P. C., WILLIAMS, P. A. & HALLOY, S. R. (1999). A weed risk assessment model for use as a biosecurity tool evaluating plant introductions. *Journal of Environmental Management* **57**, 239–251.

PIVELLO, V. R., VIEIRA, M. V., GROMBONE-GUARATINI, M. T. & MATOS, D. M. S. (2018). Thinking about super-dominant populations of native species – examples from Brazil. *Perspectives in Ecology and Conservation* **16**, 74–82.

PLAVÉN-SIGRAY, P., MATHESON, G. J., SCHIFFLER, B. C. & THOMPSON, W. H. (2017). The readability of scientific texts is decreasing over time. *Life* **6**, e27725.

POR, F. D. (1971). One hundred years of Suez Canal—a century of Lessepsian migration: retrospect and viewpoints. *Systematic Zoology* **20**, 138–159.

PROTOPOVINA, V. V., SHEVERA, M. V., ORLOV, O. O. & PANCHENKO, S. M. (2015). The transformer species of the Ukrainian Polissya. *Biodiversity Research and Conservation* **39**, 7–18.

PUTH, L. M. & POST, D. M. (2005). Studying invasion: have we missed the boat? *Ecology Letters* **8**, 715–721.

PYŠEK, P. (1995). On the terminology used in plant invasion studies. In *Plant Invasions: General Aspects and Special Problems* (eds P. PYŠEK, K. PARCH, M. REJMANEK and M. WADE), pp. 71–81. SPB Academic Publishing, Amsterdam.

PYŠEK, P., HULME, P. E., SIMBERLOFF, D., BACHER, S., BLACKBURN, T. M., CARLTON, J. T., DAWSON, W., ESSL, F., FOXCROFT, L. C., GENOVESI, P., JESCHKE, J. M., KÜHN, I., LIEBHOLD, A. M., MANDRAK, N. E., MEYERSON, L. A., *et al.* (2020). Scientists' warning on invasive alien species. *Biological Reviews* **95**, 1511–1534.

PYŠEK, P., RICHARDSON, D. M., REJMÁNEK, M., WEBSTER, G. L., WILLIAMSON, M. & KIRSCHNER, J. (2004). Alien plants in checklists and floras: towards better communication between taxonomists and ecologists. *Taxon* **53**, 131–143.

REGAN, H. M., COLYVAN, M. & BURGMAN, M. A. (2002). A taxonomy and treatment of uncertainty for ecology and conservation biology. *Ecological Applications* **12**, 618–628.

REJMANEK, M. (2011). Invasiveness. In *Encyclopedia of Biological Invasions* (eds D. SIMBERLOFF and M. REJMANEK), pp. 379–385. University of California Press, Berkeley.

RENAULT, D. (2020). A review of the phenotypic traits associated with insect dispersal polymorphism, and experimental designs for sorting out resident and disperser phenotypes. *Insects* **11**, 214.

REYNOLDS, A. M. (2012). Olfactory search behavior in the wandering albatross is predicted to give rise to Lévy flight movement patterns. *Animal Behaviour* **83**, 1225–1229.

RICCIARDI, A. (2007). Are modern biological invasions an unprecedented form of global change? *Conservation Biology* **21**, 329–336.

RICCIARDI, A. & COHEN, J. (2007). The invasiveness of an introduced species does not predict its impact. *Biological Invasions* **9**, 309–315.

RICCIARDI, A., HOOPE, M. F., MARCHETTI, M. P. & LOCKWOOD, J. L. (2013). Progress toward understanding the ecological impacts of nonnative species. *Ecological Monographs* **83**, 263–282.

RICHARDSON, D. M., FOXCROFT, L. C., LATOMBE, G., LE MAITRE, D. C., ROUGET, M. & WILSON, J. R. U. (2020). The biogeography of south African terrestrial plant invasions. In *Biological Invasions in South Africa* (eds B. W. VAN