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Globalization challenges sustainability by intensifying the ecological and economic impacts of biological invasions. These impacts may be unevenly distributed worldwide, with costs disproportionately incurred by a few regions. We identify economic cost distributions of invasions among origin and recipient countries and continents, and determine socio-economic and biodiversity-related predictors of cost dynamics. Using data filtered from the InvaCost database, which inevitably includes geographic biases in cost reporting, we found that recorded costly invasive alien species have originated from almost all regions, most frequently causing impacts to Europe. In terms of cost magnitude, reported monetary costs predominantly resulted from species with origins in Asia impacting North America. High reported cost linkages (flows) between species' native countries and their invaded countries were related to proxies of shared environments and shared trade history. This pattern can be partly attributed to the legacy of colonial expansion and trade patterns. The characterization of 'sender' and 'receiver' regions of invasive alien species and their associated cost can contribute to more sustainable economies and societies while protecting biodiversity by informing biosecurity planning and the prioritization of control efforts across invasion routes.

Introduction pathways play a pivotal role in the success of Invasive Alien Species (IAS)—the subset of alien species that have a negative environmental and/or socio-economic impact. Pathways refer to the fundamental processes that leads to the introduction of a species from one geographical location to another—marking the beginning of all alien species invasions. Increased knowledge of pathways is essential to help reduce the number of introductions and impacts of IAS and ultimately improve their management. Here we use the InvaCost database, a comprehensive repository on the global monetary impacts of IAS, combined with pathway data classified using the Convention on Biological Diversity (CBD) hierarchical classification and compiled from CABI Invasive Species Compendium, the Global Invasive Species Database (GISD) and the published literature to address five key points. Data were available for 478 individual IAS. For these, we found that both the total and annual average cost per species introduced through the ‘Stowaway’ (US$144.9bn; US$89.4m) and ‘Contaminant’ pathways (US$99.3bn; US$158.0m) were higher than species introduced primarily through the ‘Escape’ (US$87.4bn; US$25.4m) and ‘Release’ pathways (US$64.2bn; US$16.4m). Second, the recorded costs (both total and average) of species introduced unintentionally was higher than that from species introduced intentionally. Third, insects and mammals, respectively, accounted for the greatest proportion of the total cost of species introduced unintentionally and intentionally respectively, at least of the available records; ‘Stowaway’ had the highest recorded costs in Asia, Central America, North America and Diverse/Unspecified regions. Fourthly, the total cost of a species in a given location is not related to the year of first record of introduction, but time gaps might blur the true pattern. Finally, the total and average cost of IAS were not related to their number of introduction pathways. Although our findings are directly limited by the available data, they provide important material which can contribute to pathway priority measures, notably by complementing studies on pathways associated with ecologically harmful IAS. They also highlight the crucial need to fill the remaining data gaps—something that will be critical in prioritising limited management budgets to combat the current acceleration of species invasions.

Many human-introduced alien species economically impact essential industries worldwide. Management prioritization and coordination efforts towards biological invasions are hampered by a lack of comprehensive quantification of costs to key economic activity sectors. Here, we quantify and predict global invasion costs to seven major sectors and unravel the introduction pathways of species causing these costs — focusing mainly on resource-based agriculture, fishery and forestry industries. From 1970 to 2020, costs reported in the InvaCost database as pertaining to Agriculture, Fisheries, and Forestry totaled $509 bn, $1.3 bn, and $134 bn, respectively (in 2017 United States dollars). Pathways of costly species were diverse, arising predominantly from cultural and agricultural activities, through unintentional contaminants with trade, and often impacted different sectors than those for which species were initially introduced. Costs to Agriculture were pervasive and greatest in at least 37% (n = 46/123) of the countries assessed, with the United States accumulating the greatest costs for resource-based industries ($365 bn), followed by China ($101 bn), and Australia ($36 bn). We further identified 19 countries highly economically reliant on Agriculture, Fisheries, and Forestry that are experiencing massive economic impacts from biological invasions, especially in the Global South. Based on an extrapolation to fill cost data gaps, we estimated total global costs ranging at least from $517 − 1,400 bn for Agriculture, $5.7–6.5 bn for Fisheries, and $142–768 bn for Forestry, evidencing substantial underreporting in the Forestry sector in particular. Burgeoning global invasion costs challenge sustainable development and urge for improved management action to reduce future impacts on industry.

All data presented are available via the invacost R package. Related code and supplementary data available at github.com/cjabradshaw/InvaCostVersionTrends.; International audience; Biological invasions are a global challenge that has received insufficient attention. Recently available cost syntheses have provided policy and decision makers with reliable and up-to-date information on the economic impacts of invasive alien species, aiming to motivate effective management. The resultant InvaCost database is now publicly and freely accessible and enables rapid extraction of monetary cost information globally. This has facilitated knowledge sharing, developed a more integrated and multidisciplinary network of researchers, and forged multidisciplinary collaborations among diverse organisations and stakeholders. Over 50 scientific publications so far have used the database and provided detailed assessments of invasion costs across geographic, taxonomic, and spatio-temporal scales. These studies have been instrumental in guiding policy and legislative decisions, while attracting public and media attention. We provide an overview of the improved availability, reliability, and defragmentation of monetary costs, how this has enhanced invasion science as a discipline, and outline directions for future development

International audience; Biological invasions can dramatically impact natural ecosystems and human societies. However, although knowledge of the economic impacts of biological invasions provides crucial insights for efficient management and policy, reliable syntheses are still lacking. This is particularly true for low income countries where economic resources are insufficient to control the effects of invasions. In this study, we relied on the recently developed "InvaCost" database – the most comprehensive repository on the monetised impacts of invasive alien species worldwide – to produce the first synthesis of economic costs of biological invasions on the African continent. We found that the reported costs of invasions ranged between US$ 18.2 billion and US$ 78.9 billion between 1970 and 2020. This represents a massive, yet highly underestimated economic burden for African countries. More alarmingly, these costs are exponentially increasing over time, without any signs of abatement in the near future. The reported costs were mostly driven by damage caused by invaders rather than expenses incurred for management. This trend was highly skewed towards a few regions (i.e. Southern and Eastern Africa) and activity sectors (i.e. agriculture) and incurred by a small number of invasive taxa (i.e. mainly three insect pests: Chilo partellus , Tuta absoluta , Spodoptera frugiperda ). We also highlight crucial, large gaps in current knowledge on the economic costs of invasions that still need to be bridged with more widespread research effort and management actions across the continent. Finally, our study provides support for developing and implementing preventive measures as well as integrated post-invasion management actions at both national and regional levels. Considering the complex societal and economic realities in African countries, the currently neglected problem of biological invasions should become a priority for sustainable development.; Les invasions biologiques peuvent avoir un impact considérable sur les écosystèmes naturels et les sociétés humaines. Cependant, bien que les connaissances sur les impacts économiques des invasions biologiques fournissent des informations cruciales en termes de gestion, des synthèses récentes et fiables font encore défaut. Cela est particulièrement vrai pour les pays à faible revenu où les ressources économiques sont insuffisantes pour contrôler les effets des invasions. Dans cette étude, nous nous sommes appuyés sur la base de données "InvaCost" développée récemment - le référentiel le plus complet sur les impacts monétaires des espèces exotiques envahissantes dans le monde - pour produire la première synthèse des coûts économiques des invasions biologiques sur le continent africain. Nous avons constaté que les coûts déclarés des invasions varient entre 18,2 milliards de dollars américains (USD) et 78,9 milliards USD entre 1970 et 2020. Cela représente une charge économique énorme, mais encore très sous-estimée, pour les pays africains. Plus alarmant encore, ces coûts augmentent de façon exponentielle au fil du temps, sans aucun signe de réduction pour les années à venir. Les coûts reportés étaient principalement (i) dus aux dommages causés par les envahisseurs plutôt qu’aux dépenses engagées pour lutter contre leurs invasions, (ii) fortement biaisés vers quelques régions (Afrique australe et orientale) et secteurs d’activité (agriculture) et (iii) associés à un nombre restreint de taxons envahissants (essentiellement trois insectes ravageurs: Chilo partellus, Tuta absoluta, Spodoptera frugiperda). Notre étude met également en lumière de cruciales lacunes dans les connaissances actuelles sur les coûts économiques des invasions qui doivent encore être comblées par des efforts de recherche et des actions de gestion plus importants et étendus à travers le continent. Enfin, notre travail souligne la nécessité de l’élaboration et la mise en œuvre de mesures préventives pour empêcher l’introduction des espèces envahissantes, ainsi que l’intégration des actions de gestion aux niveaux national et régional. Compte tenu des réalités sociétales et économiques complexes des pays africains, le problème actuellement négligé des invasions biologiques devrait être une priorité pour le développement durable.

Biological invasions are one of the top drivers of the ongoing biodiversity crisis. An underestimated consequence of invasions is the enormity of their economic impacts. Knowledge gaps regarding economic costs produced by invasive alien species (IAS) are pervasive, particularly for emerging economies such as India—the fastest growing economy worldwide. To investigate, highlight and bridge this gap, we synthesised data on the economic costs of IAS in India. Specifically, we examine how IAS costs are distributed spatially, environmentally, sectorally, taxonomically, temporally, and across introduction pathways; and discuss how Indian IAS costs vary with socioeconomic indicators. We found that IAS have cost the Indian economy between at least US$ 127.3 billion to 182.6 billion (Indian Rupees ₹ 8.3 trillion to 11.9 trillion) over 1960–2020, and these costs have increased with time. Despite these massive recorded costs, most were not assigned to specific regions, environments, sectors, cost types and causal IAS, and these knowledge gaps are more pronounced in India than in the rest of the world. When costs were specifically assigned, maximum costs were incurred in West, South and North India, by invasive alien insects in semi-aquatic ecosystems; they were incurred mainly by the public and social welfare sector, and were associated with damages and losses rather than management expenses. Our findings indicate that the reported economic costs grossly underestimate the actual costs, especially considering the expected costs given India’s population size, gross domestic product and high numbers of IAS without reported costs. This cost analysis improves our knowledge of the negative economic impacts of biological invasions in India and the burden they can represent for its development. We hope this study motivates policymakers to address socio-ecological issues in India and launch a national biological invasion research programme, especially since economic growth will be accompanied by greater impacts of global change.

Funding Information: The authors acknowledge the very helpful input from the anonymous reviewers. Further, the authors acknowledge the French National Research Agency (ANR-14-CE02-0021) and the BNP-Paribas Foundation Climate Initiative for funding the Inva Cost project that allowed the construction of the InvaCost database. The present work was conducted following a workshop funded by the AXA Research Fund Chair of Invasion Biology and is part of the AlienScenario project funded by BiodivERsA and Belmont-Forum call 2018 on biodiversity scenarios. RNC is funded by a Research Fellowship from the Alexander von Humboldt Foundation. CD is funded by the BiodivERsA-Belmont Forum Project ?Alien Scenarios? (BMBF/PT DLR 01LC1807C). Funding Information: The authors acknowledge the very helpful input from the anonymous reviewers. Further, the authors acknowledge the French National Research Agency (ANR-14-CE02-0021) and the BNP-Paribas Foundation Climate Initiative for funding the Inva Cost project that allowed the construction of the InvaCost database. The present work was conducted following a workshop funded by the AXA Research Fund Chair of Invasion Biology and is part of the AlienScenario project funded by BiodivERsA and Belmont-Forum call 2018 on biodiversity scenarios. RNC is funded by a Research Fellowship from the Alexander von Humboldt Foundation . CD is funded by the BiodivERsA-Belmont Forum Project “Alien Scenarios” (BMBF/PT DLR 01LC1807C). Publisher Copyright: © 2021 Elsevier B.V. Invasive alien fishes have had pernicious ecological and economic impacts on both aquatic ecosystems and human societies. However, a comprehensive and collective assessment of their monetary costs is still lacking. In this study, we collected and reviewed reported data on the economic impacts of invasive alien fishes using InvaCost, the most comprehensive global database of invasion costs. We analysed how total (i.e. both observed and potential/predicted) and observed (i.e. empirically incurred only) costs of fish invasions are distributed geographically and temporally and assessed which socioeconomic sectors are most affected. Fish invasions have potentially caused the economic loss of at least US$37.08 billion (US2017 value) globally, from just 27 reported species. North America reported the highest costs (>85% of the total economic loss), followed by Europe, Oceania and Asia, with no costs yet reported from Africa or South America. Only 6.6% of the total reported costs were from invasive alien marine fish.The costs that were observed amounted to US$2.28 billion (6.1% of total costs), indicating that the costs of damage caused by invasive alien fishes are often extrapolated and/or difficult to quantify. Most of the observed costs were related to damage and resource losses (89%). Observed costs mainly affected public and social welfare (63%), with the remainder borne by fisheries, authorities and stakeholders through management actions, environmental, and mixed sectors. Total costs related to fish invasions have increased significantly over time, from

Biological invasions are one of the main threats to biodiversity within protected areas (PAs) worldwide. Meanwhile, the resilience of PAs along with their capacity to mitigate impacts from invasions remains largely unknown. Filling this knowledge gap is therefore critical for informing policy responses and optimally allocating resources invested in prevention and control strategies. Here we use the InvaCost database to address this gap from three perspectives: (i) characterizing the total cost of invasive alien species (IAS) in PAs; (ii) examining differences in mean observed costs of IAS between PAs and non-PAs; and (iii) evaluating factors affecting mean observed costs of IAS in PAs. Our results show that reported economic costs of IAS in PAs amounted to US$ 22.13 billion between 1976 and 2020, of which US$ 802.47 million were observed costs (incurred) and US$ 21.18 billion were potential costs (expected). The highest observed total costs were reported for Africa and South America; mainly caused by mammals, plants and insects; and predominantly impacted the finances of government agencies. Most of the observed total costs were reported for management (69%) versus damage (27%), however, the vast majority of management costs were reported for post-invasion actions (US$ 453 million; focused on control and eradication). PAs incurred on average higher costs than non-PAs, however, this was dependent on the environment and the continent. When analyzing costs of IAS within PAs, observed mean costs significantly differed with the environment (higher in terrestrial environments), continent (higher in Pacific islands), taxon (higher for vertebrates and invertebrates than in plants) and the human development index (developed countries incur higher costs). Managers of selected PAs surveyed acknowledged IAS as the most threatening factor, concurred on the necessity of reporting costs in PAs, and pointed to insufficient budget allocation for pre-invasion actions. Our findings highlight the need for a deeper understanding of the economic costs caused by invasions across PAs, direct driving factors and management challenges.

The United States has thousands of invasive species, representing a sizable, but unknown burden to the national economy. Given the potential economic repercussions of invasive species, quantifying these costs is of paramount importance both for national economies and invasion management. Here, we used a novel global database of invasion costs (InvaCost) to quantify the overall costs of invasive species in the United States across spatiotemporal, taxonomic, and socioeconomic scales. From 1960 to 2020, reported invasion costs totaled $4.52 trillion (USD 2017). Considering only observed, highly reliable costs, this total cost reached $1.22 trillion with an average annual cost of $19.94 billion/year. These costs increased from $2.00 billion annually between 1960-1969 to $21.08 billion annually between 2010-2020. Most costs (73%) were related to resource damages and losses ($896.22 billion), as opposed to management expenditures ($46.54 billion). Moreover, the majority of costs were reported from invaders from terrestrial habitats ($643.51 billion, 53%) and agriculture was the most impacted sector ($509.55 billion). From a taxonomic perspective, mammals ($234.71 billion) and insects ($126.42 billion) were the taxonomic groups responsible for the greatest costs. Considering the apparent rising costs of invasions, coupled with increasing numbers of invasive species and the current lack of cost information for most known invaders, our findings provide critical information for policymakers and managers.

Although the high costs of invasion are frequently cited and are a key motivation for environmental management and policy, synthesised data on invasion costs are scarce. Here, we quantify and examine the monetary costs of biological invasions in the United Kingdom (UK) using a global synthesis of reported invasion costs. Invasive alien species have cost the UK economy between US$6.9 billion and $17.6 billion (£5.4 – £13.7 billion) in reported losses and expenses since 1976. Most costs were reported for the entire UK or Great Britain (97%); country-scale cost reporting for the UK's four constituent countries was scarce. Reports of animal invasions were the costliest ($4.7 billion), then plant ($1.3 billion) and fungal ($206.7 million) invasions. Reported damage costs (i.e. excluding management costs) were higher in terrestrial ($4.8 billion) than aquatic or semi-aquatic environments ($29.8 million), and primarily impacted agriculture ($4.2 billion). Invaders with earlier introduction years accrued significantly higher total invasion costs. Invasion costs have been increasing rapidly since 1976, and have cost the UK economy $157.1 million (£122.1 million) per annum, on average. Published information on specific economic costs included only 42 of 520 invaders reported in the UK and was generally available only for the most intensively studied taxa, with just four species contributing 90% of species-specific costs. Given that many of the invasive species lacking cost data are actively managed and have well-recognised impacts, this suggests that cost information is incomplete and that totals presented here are vast underestimates owing to knowledge gaps. Financial expenditure on managing invasions is a fraction (37%) of the costs incurred through damage from invaders; greater investments in UK invasive species research and management are, therefore, urgently required.

Funding Information: The authors acknowledge the French National Research Agency (ANR-14-CE02-0021) and the BNP-Paribas Foundation Climate Initiative for funding the InvaCost project that allowed the construction of the InvaCost database. The present work was conducted following a workshop funded by the AXA Research Fund Chair of Invasion Biology and is part of the AlienScenario project funded by BiodivERsA and Belmont-Forum call 2018 on biodiversity scenarios. AN acknowledges funding from EXPRO grant no. 19-28807X (Czech Science Foundation) and long-term research development project RVO 67985939 (The Czech Academy of Sciences). CC was supported by Portuguese National Funds through Fundation para a Ci?ncia e a Tecnologia (CEECIND/02037/2017; UIDB/00295/2020 and UIDP/00295/2020). RNC was funded by a research fellowship from the Alexander von Humboldt Foundation. TWB acknowledges funding from the European Union?s Horizon 2020 research and innovation programme under the Marie Sk?odowska-Curie grant no. 747120. MG and CD were funded by the BiodivERsA-Belmont Forum Project ?Alien Scenarios? (BMBF/PT DLR 01LC1807C). NK was partially supported by the Russian Federationn Foundation for Basic Research (grant no.19-04-01029-A) [national literature survey] and the basic project of Sukachev Institute of Forest SB RAS (project no. 0287-2021-0011) [InvaCost database contribution]. DR thanks InEE-CNRS who supports the network GdR 3647 ?Invasions Biologiques?. Funds for AJT, EA and LBM contracts come from the AXA Research Fund Chair of Invasion Biology of University Paris Saclay. BL, DR and FC are French agents (affiliated, respectively, to the Mus?um National d?Histoire Naturelle, University of Rennes and Centre National de la Recherche Scientifique); their salaries, for which they are grateful, are typically not accounted for in assessment of costs on biological invasions. At last, the authors want to express their thanks for the translation of the abstract to other European languages, namely to Paride Balzani, Antonin Kouba, Sandra Hodic, and ROS Educational Consultancy Ltd & Garnock Media Ltd

Introduction pathways play a pivotal role in the success of Invasive Alien Species (IAS) – the subset of alien species that have a negative environmental and/or socio-economic impact. Pathways refer to the fundamental mechanism that leads to the introduction of a species outside of its native range – marking the beginning of all alien species invasions. Increased knowledge of pathways is essential to help reduce the flow and impacts of IAS and ultimately improve their management. Here we use the InvaCost database, a comprehensive repository on the global monetary impacts of invasive alien species, combined with the CBD hierarchical classification of introduction pathways to address four key questions: (i) Are particular IAS introduction pathways economically impactful? (ii) How are costs taxonomically and spatially distributed across pathways? (iii) Are there differences in costs between species introduced intentionally and unintentionally? and (iv) is there a relationship between the number of possible introduction pathways of IAS and their costs? We found first that both the total and average cost of species introduced through ‘Stowaways’ (US$144.9bn; US$89.4m) and ‘Contaminants’ pathways (US$99.3bn; US$158.0m) were more costly than species introduced primarily through ‘Escape’ (US$87.4bn; US$25.4m) and ‘Release’ (US$64.2bn; US$16.4m). Second, insects drove the costs of unintentional introductions whilst mammals drove the costs of intentional introductions; ‘Stowaways’ had the highest costs in Asia, Central America, North America and Diverse/Unspecified regions, whilst Antarctic-Subantarctic and Oceania incurred the greatest costs from species introduced through ‘Release’. Third, the cost of species introduced unintentionally is more than double the cost of species introduced intentionally ($192bn vs. $90bn). Equally, species introduced unintentionally cost more on average than species introduced intentionally in terms of damage, management, and mixed costs. Finally, the total and average cost of IAS was not related to their number of introduction pathways. Our findings provide important material for the targeting of priority pathways - something that will be critical in prioritising limited management budgets to combat the current acceleration of species invasions.

Invasive alien fishes have caused pernicious ecological impacts on aquatic ecosystems. However, there has not been a global appraisal of associated economic impacts. Here, we compiled reported economic impacts of invasive alien fishes using the most comprehensive global database of invasion costs (InvaCost). We analyze how fish invasion costs are distributed geographically and temporally, as well as which socioeconomic sectors are most impacted. Fish invasions have caused the economic loss of at least US$32.8 billion globally (2017 value), from only 26 reported species (of 128 known invasive alien fish species). North America had the highest costs (> 99%), followed by Europe and Asia, with no costs reported in Africa, Oceania nor South America. Very few costs from invasive fish in the marine realm were reported (0.1%). Most costs are related to resource damages and losses (97%), with relatively little spent on management; mainly impacting the fisheries sector (93%). However, when only considering empirically observed costs (without predictions), most costs were incurred by authorities and stakeholders through management, indicating that damage costs from invasive fishes are often extrapolated and/or difficult to quantify. Fish invasion costs increase markedly over time, from US$0.57 billion/year in the 1980s to US$1 billion/year in the 2000s. Fish invasions have been relatively well studied; however, economic costs have been lower than expected based on overall numbers of alien species. Accordingly, although costs are increasing, improved reporting is required to better understand how fish invasion costs are distributed across time, space and economic sectors.

Biological invasions are increasing worldwide, damaging ecosystems and socioeconomic sectors. Two decades ago, the “100 of the world’s worst” invasive alien species list was established by the IUCN to improve communications , identifying particularly damaging ‘flagship’ invaders globally (hereafter, worst). Whilst this list has bolstered invader awareness, whether worst species are especially economically damaging and how they compare to other invaders (hereafter, other) remain unknown. Here, we quantify invasion costs using the most comprehensive global database compiling them (InvaCost). We compare these costs between worst and other species against sectorial, taxonomic and regional descriptors, and examine temporal cost trends. Only 60 of the 100 worst species had invasion costs considered as highly reliable and actually observed estimates (median: US$ 43 million). On average, these costs were significantly higher than the 463 other invasive species recorded in InvaCost (median: US$ 0.53 million), although some other species had higher costs than most worst species. Damages to the environment from the worst species dominated, whereas other species largely impacted agriculture. Disproportionately highest worst species costs were incurred in North America, whilst costs were more evenly distributed for other species; animal invasions were always costliest. Proportional management expenditures were low for the other species, and surprisingly, over twice as low for the worst species. Temporally, costs increased more for the worst than other taxa; however, management spending has remained very low for both groups. Nonetheless, since 40 species had no robust and/or reported costs, the “true” cost of “some of the world’s worst” 100 invasive species still remains unknown.

The extent and impacts of biological invasions on biodiversity are largely shaped by an array of socio-ecological predictors, which exhibit high variation among countries. Yet a global synthetic perspective of how these factors vary across countries is currently lacking. Here, we investigate how a set of five socio-ecological predictors (Governance, Trade, Environmental Performance, Lifestyle and Education, Innovation) explain i) country-level established alien species (EAS) richness of eight taxonomic groups, and ii) country capacity to prevent and manage biological invasions and their impacts. Trade and Governance together best predicted the average EAS richness, increasing variance explained by up to 54% compared to models based on climatic and spatial variables only. Country-level EAS richness increased strongly with Trade, whereas high level of Governance resulted in lower EAS richness. Historical (1996) levels of Governance and Trade better explained response variables than current (2015) levels. Thus, our results reveal a historical legacy of these two predictors with profound implications for the future of biological invasions. We therefore used Governance and Trade to define a two-dimensional socio-economic space in which the position of a country captures its capacity to address issues of biological invasions. Our results provide novel insights into the complex relationship between socio-ecological predictors and biological invasions. Further, we highlight the need for designing better policies and management measures for alien species, and for integrating biological invasions in global environmental scenarios.

This chapter provides a broad overview of the interactions between invasive alien plants and climate change. Invasive alien plants are harmful nonnative plant species that have been introduced by humans outside of their “natural” geographical range. Both climate change and alien plant invasions result from human activities and can cause major environmental and socioeconomic damage. Although they can operate as independent environmental and economic threats, they can also interact. Climate change can facilitate alien plant invasions (1) by altering background environmental conditions; (2) by increasing disturbance through extreme climatic events; and (3) through human responses to climate change. While all plants, regardless of whether they are native or alien, will likely be affected by environmental change, it is widely expected that climate change will favor invasive alien plants at the expense of native plants. The way in which invasive alien plants impact the environment (e.g., modifying hydrology and soil properties, altering fire regimes) can to some extent either contribute to or exacerbate the effect of climate change. Here, we consider why and how climate change is predicted to exacerbate alien plant invasions and provide examples of how invasive alien plants can contribute to climate change. We first briefly describe what makes a plant invasive, how and why a plant becomes invasive, what stages must it go through, and what the drivers of invasion are.

Understanding the likely future impacts of biological invasions is crucial yet highly challenging given the multiple relevant environmental, socio‐economic and societal contexts and drivers. In the absence of quantitative models, methods based on expert knowledge are the best option for assessing future invasion trajectories. Here, we present an expert assessment of the drivers of potential alien species impacts under contrasting scenarios and socioecological contexts through the mid‐21st century. Based on responses from 36 experts in biological invasions, moderate (20%–30%) increases in invasions, compared to the current conditions, are expected to cause major impacts on biodiversity in most socioecological contexts. Three main drivers of biological invasions—transport, climate change and socio‐economic change—were predicted to significantly affect future impacts of alien species on biodiversity even under a best‐case scenario. Other drivers (e.g. human demography and migration in tropical and subtropical regions) were also of high importance in specific global contexts (e.g. for individual taxonomic groups or biomes). We show that some best‐case scenarios can substantially reduce potential future impacts of biological invasions. However, rapid and comprehensive actions are necessary to use this potential and achieve the goals of the Post‐2020 Framework of the Convention on Biological Diversity., Distribution of uncertainty if 15 major drivers of biological invasions will exhibit major impacts on the environment by 2050 under a best‐ and worst‐case scenario.

Highlights: • From 1960 to 2020 reported costs of US biological invasions were at least $1.22 tril. • Annual invasion costs increased from $2 bil in 1960–69 to $21 bil in 2010–20. • Most costs were damages ($896 bil), with lower management investments ($47 bil). • Agriculture sector ($510 bil) and terrestrial habitat ($644 bil) were impacted most. • Knowledge gaps in reporting make these monetary costs severely underestimated. Abstract: The United States has thousands of invasive species, representing a sizable, but unknown burden to the national economy. Given the potential economic repercussions of invasive species, quantifying these costs is of paramount importance both for national economies and invasion management. Here, we used a novel global database of invasion costs (InvaCost) to quantify the overall costs of invasive species in the United States across spatiotemporal, taxonomic, and socioeconomic scales. From 1960 to 2020, reported invasion costs totaled $4.52 trillion (USD 2017). Considering only observed, highly reliable costs, this total cost reached $1.22 trillion with an average annual cost of $19.94 billion/year. These costs increased from $2.00 billion annually between 1960 and 1969 to $21.08 billion annually between 2010 and 2020. Most costs (73%) were related to resource damages and losses ($896.22 billion), as opposed to management expenditures ($46.54 billion). Moreover, the majority of costs were reported from invaders from terrestrial habitats ($643.51 billion, 53%) and agriculture was the most impacted sector ($509.55 billion). From a taxonomic perspective, mammals ($234.71 billion) and insects ($126.42 billion) were the taxonomic groups responsible for the greatest costs. Considering the apparent rising costs of invasions, coupled with increasing numbers of invasive species and the current lack of cost information for most known invaders, our findings provide critical information for policymakers and managers.

Recent studies have highlighted cities as prime locations for the introduction, establishment, and spread of non-native and invasive species. As the hydrological arteries of cities, urban river corridors have an important role to play in influencing species invasions. This overview examines existing literature to consider (a) how the landscape functions of urban river corridors (habitat, conduit, barrier/filter, sink, and source) relate to species invasions; (b) the organismal and geographical foci of research into non-native species invasions along urban rivers; and (c) the need to more fully consider the roles that non-native species may play in the recombinant communities of novel urban river ecosystems. The review ends with an identification of research priorities at the intersection of urban river corridor function and invasion biology.