Biological invasions represent one of the main threats to biodiversity and a recognized economic burden worldwide; the issue has been included in the conservation agenda such as the Convention on Biological Diversity (CBD). Brazil is a signatory country of the CBD; however, the number of alien species records in its territory is continuously rising. To evaluate the invasive alien species (IAS) policy in Brazil, we reviewed the legislation delineating historical trends to identify potential gaps and avenues for improvement. We consulted several websites using keywords related to invasions in order to track legal instruments such as laws, decrees and regulations. We classified the documents regarding their main aims with regard to IAS, taxon and environment of interest. We found 85 legal instruments in force related to IAS published in the federal sphere up to October 2021, with decrees being the most common type. Most documents were classified as ‘control’ and ‘prevention’ and were related to all taxa and environments. Two species (wild boar Sus scrofa and golden mussel Limnoperna fortunei) have more specific legislation, probably due to their conspicuous economic impacts. We discuss policy gaps and their implications for the efficient management and prevention of new IAS introductions to the country.

Minimizing the impact of invasive alien species (IAS) on islands and elsewhere requires researchers to provide cogent information on the environmental and socioeconomic consequences of IAS to the public and policy makers. Unfortunately, this information has not been readily available owing to a paucity of scientific research and the failure of the scientific community to make their findings readily available to decision makers. This review explores the vulnerability of islands to biological invasion, reports on environmental and socioeconomic impacts of IAS on islands and provides guidance and information on technical resources that can help minimize the effects of IAS in island ecosystems. This assessment is intended to provide a holistic perspective on island-IAS dynamics, enable biologists and social scientists to identify information gaps that warrant further research and serve as a primer for policy makers seeking to minimize the impact of IAS on island systems. Case studies have been selected to reflect the most scientifically-reliable information on the impacts of IAS on islands. Sufficient evidence has emerged to conclude that IAS are the most significant drivers of population declines and species extinctions in island ecosystems worldwide. Clearly, IAS can also have significant socioeconomic impacts directly (for example human health) and indirectly through their effects on ecosystem goods and services. These impacts are manifest at all ecological levels and affect the poorest, as well as richest, island nations. The measures needed to prevent and minimize the impacts of IAS on island ecosystems are generally known. However, many island nations and territories lack the scientific and technical information, infrastructure and human and financial resources necessary to adequately address the problems caused by IAS. Because every nation is an exporter and importer of goods and services, every nation is also a facilitator and victim of the invasion of alien species. Wealthy nations therefore need to help raise the capacity of island nations and territories to minimize the spread and impact of IAS.

One of the multiple threats to protected areas worldwide, invasive plant species have the potential to decrease biodiversity and ecosystem function. We studied changes in infestation by two widespread invasive plant species – Chromolaena odorata and Mikania micrantha – in India’s Manas National Park, a critical conservation site for threatened flora and fauna. Based on field surveys in 2011 and 2019, we found that C. odorata and M. micrantha were present in most of the sampled plots and had newly invaded over 20% of the plots. However, the abundance of M. micrantha decreased in 45% of the plots while C. odorata increased in >50% of the plots. We used a decision tree-based regression with environmental variables as predictors to generate the distribution, abundance and invasion risk maps of the two species. Among environmental variables, road proximity and fire frequency had the strongest influences, respectively, on C. odorata and M. micrantha. Invaded quadrats exhibited lower native-plant diversity than non-invaded quadrats, and C. odorata specifically had a strong negative association with native-plant community structure. These invasive species have increased their range and abundance, and our predicted invasion risk maps indicate the areas where management intervention is urgently needed.

While scientific research highlights the threats of invasive alien species (IAS) to the environment and human livelihoods, another voice is rising that recognizes their beneficial impacts. With evidence increasing of the contrasting impacts of some IAS, the lack of communication between science and society makes decision-making processes more complex. Here, we consider the beneficial aspects of invasive alien plant species and take examples from other life forms to argue that, over time and space, the detrimental impacts of IAS might endanger sustainable livelihoods by increasing invasion debt manyfold. We therefore suggest that future studies reporting the positive impacts of IAS and those encouraging the management of IAS through their utilization should include value judgements that acknowledge the potential risks involved in the practice and the scale and context specificity of such studies. Studies highlighting the negative impacts of IAS should also recognize the context dependency of their findings and emphasize the benefits to be gained from the management of the IAS. We provide a more complete picture of IAS impacts that could help to inform management decisions in the face of different potential choices and the possible impacts of these choices on sustainable livelihoods in the long term.

Biodiversity conservation in the Ukrainian Carpathians cannot be accomplished without a clear understanding of the factors negatively impacting habitats and species, and long-term projection of these impacts. One factor that may severely alter the ecosystems involved is the introduction and spread of invasive plant species, but the potential distribution and spatial aggregation of suitable habitats for several invaders have not been quantified. The Maxent approach was used to model the potential establishment within the entire mountain range of 11 alien invasive plant species based on stratified sampling and herbaria records and six variables representing climatic extremes, topography, and anthropogenic and natural disturbances. Predictions of habitat suitability were projected to two future change scenarios depicting increasing rates of climate warming and anthropogenic disturbances in 2050 and 2100. Under current climate and disturbance patterns, the models predicted suitable habitats for invasive species establishment to be aggregated in the south-west, east and north-east of the Ukrainian Carpathians, along major rivers and roads at altitudes of up to c. 700 m. Eight per cent of the total area within protected areas was predicted to be potentially susceptible to invasion by at least one species, with 13% of these susceptible habitats being suitable for all 11 species. Under the future change scenarios, suitable habitat ranges increased significantly in the entire study area and within regions of high conservation value. All species were projected to gain suitable habitats at higher altitudes along linear habitats and to potentially expand their ranges laterally from habitats predicted as suitable for current conditions along small rivers and roads. Under the scenario solely of increased average seasonal temperatures, suitable habitats for the establishment of at least one species within protected areas and a proposed ecological network increased by more than 15 percentage points by 2050 and by more than 30 percentage points by 2100 when compared with predictions for current conditions. Similar future patterns were discernible for the aggregation of suitable habitats for all 11 species. Incorporating increases in anthropogenic pressures into climatic-change projections led to a significantly greater projected expansion of suitable habitats for establishment as compared to scenarios considering only climatic changes. As the 11 species have already established viable populations within protected areas, further spread of at least one species is likely if conservation planning is not changed to include the management of invasive species in such areas.

Invasive species can have disastrous effects on the ecosystems they invade, requiring costly, labour-intensive mitigation. Public awareness campaigns are often used as a tool to reduce these species’ impacts. While heralded as useful and cost-effective, little evidence suggests that these campaigns contribute to meaningful biological outcomes. Furthermore, awareness campaigns are relatively understudied despite their usage as a common approach to mitigating invasive species. We conducted a literature review to assess publications that evaluated the efficacy of public awareness campaigns for managing invasive species. Out of 4382 papers initially extracted for analysis, we determined that 24 of them included studies conducted on awareness campaigns for invasive species. Four public awareness campaigns were deemed a ‘success’, and the other campaigns’ success was indeterminable due to study design. Our study revealed that inconsistencies in defined end points, unclear procedures and variability of campaigns contribute to there being insufficient evidence to determine the efficacy of public awareness campaigns. To evaluate the true efficacy of public awareness campaigns, we recommend that organizations conducting such campaigns implement rigorous and standardized assessments (e.g., Before–After Control–Impact designs or Bayesian analyses) that include measures of not just changes in the knowledge and behaviour of target audiences, but also relevant biological outcomes.

Ants are among the worst invasive species, and can have tremendous negative impacts on native biodiversity, agriculture, estates, property and human health. Invasive ants are extremely difficult to control, and thus early detection is essential to prevent ant invasions, in particular through surveillance efforts at ports of entry. This paper assesses the potential distribution of 14 of the worst invasive ant species in France, under current and future climatic conditions. Consensus species distribution models, using five different modelling techniques, three global climate models and two CO2 emission scenarios, indicated that France presented suitable areas for 10/14 species, including five listed on the Invasive Species Specialist Group's selection of the world's 100 worst invasive species. Among these 10 species, eight were predicted to increase their potential range with climate change. Areas with the highest concentration of potential invaders were mainly located along the coastline, especially in the south-west of France, but all departments appeared to be climatically suitable for at least two invasive species. A ranking of climatic suitability per species for 17 major airports and 14 maritime ports indicated that the ports of entry with the highest suitability were located in Biarritz, Toulon and Nice, and the species with the greatest potential distribution in France were Lasius neglectus and Linepithema humile, followed by Solenopsis richteri, Pheidole megacephala and Wasmannia auropunctata.

Invasive alien species represent a multifaceted management problem in terms of threats to biodiversity and ecosystems and their impacts on agriculture and human well-being. Ambrosia artemisiifolia is an invasive alien plant in Europe that affects the human population as its already highly allergenic pollen can interact with air pollutants, resulting in detrimental effects on health. In this context, the invasive beetle Ophraella communa was proposed as a biocontrol agent of A. artemisiifolia, as it feeds on its leaves, leading to a decrease in pollen production. This paper takes advantage of the different co-occurrence classes obtained by the ecological niche models inferred for both of these species based on current and future climatic conditions. We integrate them with spatial data regarding major air pollutants (nitrogen dioxide and fine particulate matter). We couple this information with European human population density data at a narrow territorial scale to infer current and future statistically significant hotspots of health risk. The Netherlands and the UK host the widest hotspots within their national territory for both current (7.09% and 3.54%, respectively) and future (15.04% and 6.70%, respectively) scenarios. Considering the alarming results obtained for some areas, the monitoring and biocontrol of A. artemisiifolia should be applied as a European strategy.

Study of the ecological and economic effects of invasive species has paralleled their progressively pervasive influence worldwide, yet their cultural impacts remain largely unexamined and therefore unrecognized. Unlike biological systems, where the ecological consequences of biological invasions are primarily negative, from an ethnoscientific standpoint, invasive species' impacts on cultural systems span a range of effects. Biological invasions affect cultural groups in myriad, often unpredictable and at times contradictory ways. This review groups case studies into a conceptual matrix suggesting three categorically different cultural impacts of invasive species. Culturally impoverishing invasive species precipitate the loss or replacement of culturally important native species and their associated cultural practices. Culturally enriching invasive species augment cultural traditions, through their inclusion in lexicons, narratives, foods, pharmacopoeias and other tangible and intangible ends. Culturally facilitating invasive species can provide continuity and reformulation of traditional ethnobiological practices. An understanding of the processes by which invasive biota become culturally enriching, facilitating, or impoverishing can contribute to articulating interdisciplinary programmes aimed at simultaneously conserving biological and cultural diversity.

In contemporary environmental conservation, species are judged in terms of their origin (‘nativeness’), as well as their behaviour and impacts (‘invasiveness’). In many instances, however, the term ‘non-native’ has been used as a proxy for harmfulness, implying the need for control. Some scientists have attempted to discourage this practice, on the grounds that it is inappropriate and counterproductive to judge species on their origin alone. However, to date, no empirical data exist on the degree to which nativeness in itself (that is, a species’ origin) shapes people's attitudes towards management interventions in practice. This study addresses this void, demonstrating empirically that both the public and invasive species professionals largely ignore a species’ origin when evaluating the need for conservation action. Through a questionnaire-based survey of the general public and invasive species experts in both Scotland and Canada, the study revealed that perceived abundance and damage to nature and the economy, rather than non-nativeness, informed attitudes towards species management, empirically substantiating the claim that a species’ perceived abundance and impact, and not its origin, is what really matters to most people. Natural resource management should thus focus explicitly on impact-related criteria, rather than on a species’ origin.

Invasive alien species (IASs) on islands have broad impacts across biodiversity, agriculture, economy, health and culture, which tend to be stronger than on continents. Across small-island developing states (SIDSs), although only a small number of IASs are widely distributed, many more, including those with greatest impact, are found on only a small number of islands. Patterns of island invasion are not consistent across SIDS geographic regions, with differences attributable to correlated patterns in island biogeography and human development. We identify 15 of the most globally prevalent IASs on islands. IAS impacts on islands are exacerbated through interactions with a number of other global change threats, including over-exploitation, agricultural intensification, urban development and climate change. Biosecurity is critical in preventing IAS invasion of islands. Eradication of IASs on islands is possible at early stages of invasion, but otherwise is largely restricted to invasive mammals, or otherwise control is the only option. Future directions in IAS management and research on islands must consider IASs within a broader portfolio of threats to species, ecosystems and people's livelihoods on islands. We advocate for stronger collaborations among island countries and territories faced with the same IASs in similar socio-ecological environments.

Bivalves are among the main groups of invasive freshwater species, with the Asian clam genus Corbicula in particular being widely distributed. While global studies have focused on Corbicula fluminea (Müller, 1774), the invasive potential of Corbicula largillierti (Philippi, 1844) and Corbicula fluminalis (Müller, 1774) is still unknown. The spread of invasive species may be intensified by climate change. We estimated and compared environmentally suitable areas for these species under hypothetical climate scenarios, generating global maps of invasion risk. We found large climatically suitable areas for C. largillierti and C. fluminalis (under species distribution models) and that their invasive potential is currently underestimated. The analysis revealed many areas in which changing climate may favour the invasion of Corbicula spp.