Explore the vast range of titles available.

Ecological and socioeconomic impacts from biological invasions are rapidly escalating worldwide. While effective management underpins impact mitigation, such actions are often delayed, insufficient or entirely absent. Presently, management delays emanate from a lack of monetary rationale to invest at early invasion stages, which precludes effective prevention and eradication. Here, we provide such rationale by developing a conceptual model to quantify the cost of inaction, i.e., the additional expenditure due to delayed management, under varying time delays and management efficiencies. Further, we apply the model to management and damage cost data from a relatively data-rich genus (Aedes mosquitoes). Our model demonstrates that rapid management interventions following invasion drastically minimise costs. We also identify key points in time that differentiate among scenarios of timely, delayed and severely delayed management intervention. Any management action during the severely delayed phase results in substantial losses (>50% of the potential maximum loss). For Aedes spp., we estimate that the existing management delay of 55 years led to an additional total cost of approximately $ 4.57 billion (14% of the maximum cost), compared to a scenario with management action only seven years prior (< 1% of the maximum cost). Moreover, we estimate that in the absence of management action, long-term losses would have accumulated to US$ 32.31 billion, or more than seven times the observed inaction cost. These results highlight the need for more timely management of invasive alien species—either pre-invasion, or as soon as possible after detection—by demonstrating how early investments rapidly reduce long-term economic impacts.

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.

Invasive ants are amongst the most destructive and widespread invaders across the globe; they can strongly alter invaded ecosystems and are responsible for the loss of native ant species. Several studies have reported that invasive ants can also lead to substantial economic costs. In this study, we search, describe and analyse 1342 reported costs of invasive ants compiled in the InvaCost database. Economic costs, reported since 1930 for 12 ant species in 27 countries, totalled US$ 51.93 billion, from which US$ 10.95 billion were incurred, and US$ 40.98 billion were potential costs (i.e., expected or predicted costs). More than 80% of total costs were associated with only two species, Solenopsis invicta and Wasmannia auropunctata; and two countries, the USA and Australia. Overall, damage costs amounted to 92% of the total cost, mainly impacting the agriculture, public and social welfare sectors. Management costs were primarily post-invasion management (US$ 1.79 billion), with much lower amounts dedicated to prevention (US$ 235.63 million). Besides the taxonomic bias, cost information was lacking for an average of 78% of the invaded countries. Moreover, even in countries where costs were reported, such information was available for only 56% of the invaded locations. Our synthesis suggests that the global costs of invasive ants are massive but largely biased towards developed economies, with a huge proportion of underreported costs, and thus most likely grossly underestimated. We advocate for more and improved cost reporting of invasive ants through better collaborations between managers, practitioners and researchers, a crucial basis for adequately informing future budgets and improving proactive management actions of invasive ants.

Biological invasions continue to threaten the stability of ecosystems and societies that are dependent on their services. Whilst the ecological impacts of invasive alien species (IAS) have been widely reported in recent decades, there remains a paucity of information concerning their economic impacts. Europe has strong trade and transport links with the rest of the world, facilitating hundreds of IAS incursions, and largely centralised decision-making frameworks. The present study is the first comprehensive and detailed effort that quantifies the costs of IAS collectively across European countries and examines temporal trends in these data. In addition, the distributions of costs across countries, socioeconomic sectors and taxonomic groups are examined, as are socio-economic correlates of management and damage costs. Total costs of IAS in Europe summed to US $140.20 billion (or €116.61 billion) between 1960 and 2020, with the majority (60%) being damage-related and impacting multiple sectors. Costs were also geographically widespread but dominated by impacts in large western and central European countries, i.e. the UK, Spain, France, and Germany. Human population size, land area, GDP, and tourism were significant predictors of invasion costs, with management costs additionally predicted by numbers of introduced species, research effort and trade. Temporally, invasion costs have increased exponentially through time, with up to US$ 23.58 billion (€19.64 billion) in 2013, and US$139.56 billion (€116.24 billion) in impacts extrapolated in 2020. Importantly, although these costs are substantial, there remain knowledge gaps on several geographic and taxonomic scales, indicating that these costs are severely underestimated. We, thus, urge increased and improved cost reporting for economic impacts of IAS and coordinated international action to prevent further spread and mitigate impacts of IAS populations.

In addition to being a major threat to biodiversity and ecosystem functioning, biological invasions also have profound impacts on economies and human wellbeing. However, the threats posed by invasive species often do not receive adequate attention and lack targeted management. In part, this may result from different or even ambivalent perceptions of invasive species which have a dual effect for stakeholders—being simultaneously a benefit and a burden. For these species, literature that synthesizes best practice is very limited, and analyses providing a comprehensive understanding of their economics are generally lacking. This has resulted in a critical gap in our understanding of the underlying trade-offs surrounding management efforts and approaches. Here, we explore qualitative trends in the literature for invasive species with dual effects, drawing from both the recently compiled InvaCost database and international case studies. The few invasive species with dual roles in InvaCost provide evidence for a temporal increase in reporting of costs, but with benefits relatively sporadically reported alongside costs. We discuss methods, management, assessment and policy frameworks dedicated to these species, along with lessons learned, complexities and persisting knowledge gaps. Our analysis points at the need to enhance scientific understanding of those species through inter- and cross-disciplinary efforts that can help advance their management.

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.

AimTo assess spatio-temporal and taxonomic patterns of available information on the costs of invasive freshwater bivalves, as well as to identify knowledge gaps.LocationGlobal.Time period1980–2020.Taxon studiedBivalvia.MethodsWe synthesize published global economic costs of impacts from freshwater bivalves using the InvaCost database and associated R package, explicitly considering the reliability of estimation methodologies, cost types, economic sectors and impacted regions.ResultsCumulative total global costs of invasive macrofouling bivalves were $ 63.7 billion (2017 US$) across all regions and socio-economic sectors between 1980 and 2020. Costs were heavily biased taxonomically and spatially, dominated by two families, Dreissenidae and Cyrenidae (Corbiculidae), and largely reported in North America. The greatest share of reported costs ($ 31.5 billion) did not make the distinction between damage and management. However, of those that did, damages and resource losses were one order of magnitude higher ($ 30.5 billion) than control or preventative measures ($ 1.7 billion). Moreover, although many impacted socio-economic sectors lacked specification, the largest shares of costs were incurred by authorities and stakeholders ($ 27.7 billion, e.g., public and private sector interventions) and through impacts on public and social welfare ($ 10.1 billion, e.g., via power/drinking water plant and irrigation system damage) in North America. Average cost estimates over the entire period amounted to approximately $ 1.6 billion per year, most of which was incurred in North America.Main conclusionsOur results highlight the burgeoning economic threat caused by invasive freshwater bivalves, offering a strong economic incentive to invest in preventative management such as biosecurity and rapid response eradications. Even if the damages and resource losses are severely understated because economic impacts are lacking for most invaded countries and invasive bivalve species, these impacts are substantial and likely growing.

A large and increasing number of ecosystems of the planet are now invaded by alien species, resulting in detrimental impacts on biodiversity, human health, and ecosystem services (IPBES 2019). Many of these impacts can be defined and quantified as economic costs; expenditures to prevent, reduce or mitigate the losses caused by invasive alien species (IAS). Reports on the global economic costs over the last 50 years estimate that IAS are responsible for a minimum of US$1.288 trillion (2017 US dollars) in damages, a number that is steadily rising over time (Diagne et al. 2021a). Understanding and estimating economic damages caused by IAS is particularly important given that new introductions of alien species and impacts are increasing globally with no sign of slowing down (Seebens et al. 2017; Essl et al. 2020). In addition, just as current and future projections of numbers and types of IAS vary across ecosystems (van Kleunen et al. 2015; Essl et al. 2020), impacts and costs of biological invasions differ widely across space and time (Angulo et al. 2021b; Diagne et al. 2021a). Improving economic cost estimates of biological invasions across regions helps scientists, managers, and stakeholders to develop and inform benefit-cost analyses and policies for dealing with invasive alien species. Previous studies have modelled and estimated the economic costs of biological invasions for specific countries (e.g., Pimentel et al. 2005; Hoffmann and Broadhurst 2016) or globally (e.g., Diagne et al. 2021a), but a standardized assessment of costs of biological invasions with detailed information for countries and regions was lacking for most regions of the world. In this special issue on the “The Economic costs of biological invasions in the world,” 63 authors address this issue by bringing together 19 papers from 13 countries and 6 supra-national regions that report on the economic cost-dimension of biological invasions (Fig. 1, Table 1). Collectively, they provide a global, innovative perspective detailing the economic costs of biological invasions while also providing regional information to help raise public awareness, and support efficient and cost-effective decision-making.

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.

The legacy of deliberate and accidental introductions of invasive alien species to Australia has had a hefty economic toll, yet quantifying the magnitude of the costs associated with direct loss and damage, as well as for management interventions, remains elusive. This is because the reliability of cost estimates and under-sampling have not been determined. We provide the first detailed analysis of the reported costs associated with invasive species to the Australian economy since the 1960s, based on the recently published InvaCost database and supplementary information, for a total of 2078 unique cost entries. Since the 1960s, Australia has spent or incurred losses totalling at least US $298.58 billion (2017 value) or AU$ 389.59 billion (2017 average exchange rate) from invasive species. However, this is an underestimate given that costs rise as the number of estimates increases following a power law. There was an average 1.8–6.3-fold increase in the total costs per decade since the 1970s to the present, producing estimated costs of US $6.09–57.91 billion year -1 (all costs combined) or US$ 225.31 million–6.84 billion year -1 (observed, highly reliable costs only). Costs arising from plant species were the highest among kingdoms (US $151.68 billion), although most of the costs were not attributable to single species. Of the identified weedy species, the costliest were annual ryegrass ( Lolium rigidum ), parthenium ( Parthenium hysterophorus ) and ragwort ( Senecio jacobaea ). The four costliest classes were mammals (US$ 48.63 billion), insects (US $11.95 billion), eudicots (US$ 4.10 billion) and monocots (US$1.92 billion). The three costliest species were all animals – cats ( Felis catus ), rabbits ( Oryctolagus cuniculus ) and red imported fire ants ( Solenopsis invicta ). Each State/Territory had a different suite of major costs by species, but with most (3–62%) costs derived from one to three species per political unit. Most (61%) of the reported costs applied to multiple environments and 73% of the total pertained to direct damage or loss compared to management costs only, with both of these findings reflecting the availability of data. Rising incursions of invasive species will continue to have substantial costs for the Australian economy, but with better investment, standardised assessments and reporting and coordinated interventions (including eradications), some of these costs could be substantially reduced.