Biological invasions are a population-level rather than a species-level phenomenon.

Biological invasions pose a rapidly expanding threat to the persistence, functioning and service provisioning of ecosystems globally, and to socio-economic interests. The stages of successful invasions are driven by the same mechanism that underlies adaptive changes across species in general-via natural selection on intraspecific variation in traits that influence survival and reproductive performance (i.e., fitness). Surprisingly, however, the rapid progress in the field of invasion science has resulted in a predominance of species-level approaches (such as deny lists), often irrespective of natural selection theory, local adaptation and other population-level processes that govern successful invasions. To address these issues, we analyse non-native species dynamics at the population level by employing a database of European freshwater macroinvertebrate time series, to investigate spreading speed, abundance dynamics and impact assessments among populations. Our findings reveal substantial variability in spreading speed and abundance trends within and between macroinvertebrate species across biogeographic regions, indicating that levels of invasiveness and impact differ markedly. Discrepancies and inconsistencies among species-level risk screenings and real population-level data were also identified, highlighting the inherent challenges in accurately assessing population-level effects through species-level assessments. In recognition of the importance of population-level assessments, we urge a shift in invasive species management frameworks, which should account for the dynamics of different populations and their environmental context. Adopting an adaptive, region-specific and population-focused approach is imperative, considering the diverse ecological contexts and varying degrees of susceptibility. Such an approach could improve and refine risk assessments while promoting mechanistic understandings of risks and impacts, thereby enabling the development of more effective conservation and management strategies.

Field and laboratory microplastics uptake by a freshwater shrimp.

Microplastics are widespread pollutants, but few studies have linked field prevalence in organisms to laboratory uptakes. Aquatic filter feeders may be particularly susceptible to microplastic uptake, with the potential for trophic transfer to higher levels, including humans. Here, we surveyed microplastics from a model freshwater shrimp, common caraidina (Caridina nilotica) inhabiting the Crocodile River in South Africa to better understand microplastic uptake rates per individual. We then use functional response analysis (feeding rate as a function of resource density) to quantify uptake rates by shrimps in the laboratory. We found that microplastics were widespread in C. nilotica, with no significant differences in microplastic abundances among sampled sites under varying land uses, with an average abundance of 6.2 particles per individual. The vast majority of microplastics found was fibres (86.1%). Shrimp microplastic accumulation patterns were slightly higher in the laboratory than the field, where shrimp exhibited a hyperbolic Type II functional response model under varying exposure concentrations. Maximum feeding rates of 20 particles were found over a 6 h feeding period, and uptake evidenced at even the lowest laboratory concentrations (~10 particles per mL). These results highlight that microplastic uptake is widespread in field populations and partly density dependent, with field concentrations corroborating uptake rates recorded in the laboratory. Further research is required to elucidate trophic transfer from these taxa and to understand potential physiological impacts.

Economic costs of non-native species in Türkiye: A first national synthesis.

Biological invasions are increasingly recognised as a major global change that erodes ecosystems, societal well-being, and economies. However, comprehensive analyses of their economic ramifications are missing for most national economies, despite rapidly escalating costs globally. Türkiye is highly vulnerable to biological invasions owing to its extensive transport network and trade connections as well as its unique transcontinental position at the interface of Europe and Asia. This study presents the first analysis of the reported economic costs caused by biological invasions in Türkiye. The InvaCost database which compiles invasive non-native species' monetary costs was used, complemented with cost searches specific to Türkiye, to describe the spatial and taxonomic attributes of costly invasive non-native species, the types of costs, and their temporal trends. The total economic cost attributed to invasive non-native species in Türkiye (from 202 cost reporting documents) amounted to US$ 4.1 billion from 1960 to 2022. However, cost data were only available for 87 out of 872 (10%) non-native species known for Türkiye. Costs were biased towards a few hyper-costly non-native taxa, such as jellyfish, stink bugs, and locusts. Among impacted sectors, agriculture bore the highest total cost, reaching US$ 2.85 billion, followed by the fishery sector with a total cost of US$ 1.20 billion. Management (i.e., control and eradication) costs were, against expectations, substantially higher than reported damage costs (US$ 2.89 billion vs. US$ 28.4 million). Yearly costs incurred by non-native species rose exponentially over time, reaching US$ 504 million per year in 2020-2022 and are predicted to increase further in the next 10 years. A large deficit of cost records compared to other countries was also shown, suggesting a larger monetary underestimate than is typically observed. These findings underscore the need for improved cost recording as well as preventative management strategies to reduce future post-invasion management costs and help inform decisions to manage the economic burdens posed by invasive non-native species. These insights further emphasise the crucial role of standardised data in accurately estimating the costs associated with invasive non-native species for prioritisation and communication purposes.

Taming the terminological tempest in invasion science.

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.

Spatiotemporal variation in macroplastic abundances along a subtropical Austral river system.

Plastic pollution is a ubiquitous problem that poses a threat to society and the environment. The issue is especially pervasive in the aquatic environment, where large amounts of plastic debris accumulate from numerous anthropogenic pathways. Relatively little is known about the extent of macroplastics in African subtropical Austral rivers, where management strategies are lacking. This study quantifies and compares the variation in macroplastic abundances along the Mvudi River, South Africa, over four sites and four seasons. We observed a non-significant difference in macroplastic abundance and variation across sites and seasons, with pollution therefore widespread across these contexts. However, the diversity of plastic debris (i.e. γ-diversity value) decreased generally along sites, with most macroplastic items being collected during winter, and fewer macroplastic during autumn. We observed high abundances of macroplastic debris on the shoreline compared to the mainstream, with high proportional abundances of plastic bags and film (> 57.8%) macroplastic physical type across all sites and seasons. We also observed a high proportional abundance of the polymer polypropylene (> 25.3%) across seasons. The information derived from this study serves as the baseline for understanding seasonal variations in plastic debris and their driving factors on this and other subtropical Austral rivers.

Native molluscs alleviate water quality impacts of invasive crayfish.

Freshwaters are considered to be the most vulnerable ecosystems facing biological invasions, and the red swamp crayfish (Procambarus clarkii) is one of the most widespread aquatic invasive species in the world. P. clarkii has negative impacts on water quality in the lakes that it invades by, for instance, increasing their turbidity and nutrient concentrations and reducing macrophyte biomass. However, native taxa such as snails and mussels could potentially help to maintain a clear-water status in lakes by grazing on periphyton or by phytoplankton filtration. To examine the potential negative effects of P. clarkii on the clear-water state in lakes dominated by the macrophyte Vallisneria denseserrulata and the potential for native species to buffer these effects, we tested the crayfish impact in the absence and presence of the snail Bellamya aeruginosa and the mussel Sinanodonta woodiana at different biomasses. In the presence of crayfish, total suspended solids, total phosphorus, and chlorophyll a concentrations significantly increased compared to the control treatments without crayfish. However, when crayfish coexisted with snails or mussels, these three environmental variables all decreased in concentration compared to the crayfish-only treatment. Low (500 g/m2) and high (1500 g/m2) snail or mussel biomass had similar buffering effects. Macrophyte biomass in the crayfish and high mussel biomass treatment was 43 % higher than in the crayfish-only treatment. Native molluscs therefore alleviated the negative effects of crayfish on lake water quality and promoted native macrophyte growth. We conclude that a thriving native mollusc community may help in maintaining the clear-water state in lakes following crayfish invasion.

The wild cost of invasive feral animals worldwide.

Invasive non-native species are a growing burden to economies worldwide. While domesticated animals (i.e. livestock, beasts of burden or pets) have enabled our ways of life and provide sustenance for countless individuals, they may cause substantial impacts when they escape or are released (i.e. become feral) and then become invasive with impacts. We used the InvaCost database to evaluate monetary impacts from species in the Domestic Animal Diversity Information System database. We found a total cost of $141.95 billion from only 18 invasive feral species. Invasive feral livestock incurred the highest costs at $90.03 billion, with pets contributing $50.93 billion and beasts of burden having much lower costs at $0.98 billion. Agriculture was the most affected sector at $80.79 billion, followed by the Environment ($43.44 billion), and Authorities-Stakeholders sectors ($5.52 billion). Damage costs comprised the majority ($124.94 billion), with management and mixed damage-management costs making up the rest ($9.62 and $7.38 billion, respectively). These economic impacts were observed globally, where Oceania, North America and Europe were the most impacted regions. Islands recorded a higher economic burden than continental areas, with livestock species dominating costs more on islands than mainlands compared to other feral species. The costs of invasive feral animals were on average twice higher than those of wild species. The management of invasive feral populations requires higher investment, updated regulations, and comprehensive risk assessments. These are especially complex when considering the potential conflicts arising from interventions with species that have close ties to humans. Effective communication to raise public awareness of the impacts of feral populations and appropriate legislation to prevent or control such invasive feral populations will substantially contribute to minimizing their socioeconomic and environmental impacts.

Economic impact disharmony in global biological invasions.

A dominant syndrome of the Anthropocene is the rapid worldwide spread of invasive species with devastating environmental and socio-economic impacts. However, the dynamics underlying the impacts of biological invasions remain contested. A hypothesis posits that the richness of impactful invasive species increases proportionally with the richness of non-native species more generally. A competing hypothesis suggests that certain species features disproportionately enhance the chances of non-native species becoming impactful, causing invasive species to arise disproportionately relative to the numbers of non-native species. We test whether invasive species with reported monetary costs reflect global numbers of established non-native species among phyla, classes, and families. Our results reveal that numbers of invasive species with economic costs largely reflect non-native species richness among taxa (i.e., in 96 % of families). However, a few costly taxa were over- and under-represented, and their composition differed among environments and regions. Chordates, nematodes, and pathogenic groups tended to be the most over-represented phyla with reported monetary costs, with mammals, insects, fungi, roundworms, and medically-important microorganisms being over-represented classes. Numbers of costly invasive species increased significantly with non-native richness per taxon, while monetary cost magnitudes at the family level were also significantly related to costly invasive species richness. Costs were biased towards a few 'hyper-costly' taxa (such as termites, mosquitoes, cats, weevils, rodents, ants, and asters). Ordination analysis revealed significant dissimilarity between non-native and costly invasive taxon assemblages. These results highlight taxonomic groups which harbour disproportionately high numbers of costly invasive species and monetary cost magnitudes. Collectively, our findings support prevention of arrival and containment of spread of non-native species as a whole through effective strategies for mitigation of the rapidly amplifying impacts of invasive species. Yet, the hyper- costly taxa identified here should receive greater focus from managers to reduce impacts of current invasive species.

Temporal patterns of fucoxanthin in four species of European marine brown macroalgae.

Brown seaweeds are a rich source of carotenoids, particularly fucoxanthin, which has a wide range of potential health applications. Fucoxanthin fluctuates within and among seaweeds over time, frustrating efforts to utilise this resource. Thus, we require comprehensive analyses of long- and short-term concentrations across species in field conditions. Here, we used High Performance Liquid Chromatography to compare fucoxanthin content in four brown macroalgae, Ascophyllum nodosum, Fucus serratus, Fucus vesiculosus and Saccharina latissima, monthly for 1 year. F. serratus and F. vesiculosus had significantly higher fucoxanthin content (mg/g), which was highest in Spring (0.39 ± 0.04) and Autumn (0.45 ± 0.04) [mean (± SE)]. Two species, A. nodosum and F. serratus, were collected monthly at the same location for a further two non-consecutive years. For both A. nodosum and F. serratus, a significant interaction effect of seasons and years was identified, highlighting that there is variation in fucoxanthin content among and within species over time. We also show that fucoxanthin content differs significantly among months even within seasons. Therefore, it is not sufficient to assess fucoxanthin in single months to represent seasonality. We discuss how weather, nutrients and reproduction may have driven the seasonal variation, and reveal patterns of fucoxanthin concentration that can provide information concerning its availability for many important medical functions.

Recent advances in availability and synthesis of the economic costs of biological invasions.

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 biological invasions, aiming to motivate effective management. The resultant InvaCost database is now publicly and freely accessible and enables rapid extraction of monetary cost information. This has facilitated knowledge sharing, developed a more integrated and multidisciplinary network of researchers, and forged multidisciplinary collaborations among diverse organizations and stakeholders. Over 50 scientific publications so far have used the database and have provided detailed assessments of invasion costs across geographic, taxonomic, and spatiotemporal scales. These studies have provided important information that can guide future policy and legislative decisions on the management of biological invasions while simultaneously attracting public and media attention. We provide an overview of the improved availability, reliability, standardization, and defragmentation of monetary costs; discuss how this has enhanced invasion science as a discipline; and outline directions for future development.

Density-dependent predatory impacts of an invasive beetle across a subantarctic archipelago.

Biological invasions represent a major threat to biodiversity, especially in cold insular environments characterized by high levels of endemism and low species diversity which are heavily impacted by global warming. Terrestrial invertebrates are very responsive to environmental changes, and native terrestrial invertebrates from cold islands tend to be naive to novel predators. Therefore, understanding the relationships between predators and prey in the context of global changes is essential for the management of these areas, particularly in the case of non-native predators. Merizodus soledadinus (Guérin-Méneville, 1830) is an invasive non-native insect species present on two subantarctic archipelagos, where it has extensive distribution and increasing impacts. While the biology of M. soledadinus has recently received attention, its trophic interactions have been less examined. We investigated how characteristics of M. soledadinus, its density, as well as prey density influence its predation rate on the Kerguelen Islands where the temporal evolution of its geographic distribution is precisely known. Our results show that M. soledadinus can have high ecological impacts on insect communities when present in high densities regardless of its residence time, consistent with the observed decline of the native fauna of the Kerguelen Islands in other studies. Special attention should be paid to limiting factors enhancing its dispersal and improving biosecurity for invasive insect species.

Invasive hematophagous arthropods and associated diseases in a changing world.

Biological invasions have increased significantly with the tremendous growth of international trade and transport. Hematophagous arthropods can be vectors of infectious and potentially lethal pathogens and parasites, thus constituting a growing threat to humans-especially when associated with biological invasions. Today, several major vector-borne diseases, currently described as emerging or re-emerging, are expanding in a world dominated by climate change, land-use change and intensive transportation of humans and goods. In this review, we retrace the historical trajectory of these invasions to better understand their ecological, physiological and genetic drivers and their impacts on ecosystems and human health. We also discuss arthropod management strategies to mitigate future risks by harnessing ecology, public health, economics and social-ethnological considerations. Trade and transport of goods and materials, including vertebrate introductions and worn tires, have historically been important introduction pathways for the most prominent invasive hematophagous arthropods, but sources and pathways are likely to diversify with future globalization. Burgeoning urbanization, climate change and the urban heat island effect are likely to interact to favor invasive hematophagous arthropods and the diseases they can vector. To mitigate future invasions of hematophagous arthropods and novel disease outbreaks, stronger preventative monitoring and transboundary surveillance measures are urgently required. Proactive approaches, such as the use of monitoring and increased engagement in citizen science, would reduce epidemiological and ecological risks and could save millions of lives and billions of dollars spent on arthropod control and disease management. Last, our capacities to manage invasive hematophagous arthropods in a sustainable way for worldwide ecosystems can be improved by promoting interactions among experts of the health sector, stakeholders in environmental issues and policymakers (e.g. the One Health approach) while considering wider social perceptions.

Nowhere to go! Microplastic abundances in freshwater fishes living near wastewater plants.

Microplastic presence in aquatic environments is a major problem globally. This study quantified microplastic abundances in fish species across two systems in South Africa around wastewater treatment works. Fish (n = 163) were examined for microplastic in gills and gastrointestinal tracts. Microplastic levels were generally low during the cool-dry season (mean 11.0 - 34.0 particles per fish taxon), and high during the hot-wet season (mean 10.0 - 119.0 particles per fish taxon). The microplastic concentrations per fish were similar between these systems, with downstream of wastewater treatment plants having high microplastic abundances. Although benthopelagic feeders were dominant, pelagic feeders had high microplastic abundances (range 20-119 particles), followed by benthopelagic (range 10-110 particles) and demersal (22 particles) feeders. Multiple regression analysis revealed a significant positive relationship between fish standard length and total microplastic levels, which suggests fish consume more microplastics due to increased food demand as a result of growth.

Illegal mining impacts on freshwater Potamonautid crab in a subtropical Austral highland biosphere reserve.

The contamination of surface water by heavy metals, especially mercury, has become a global issue. This problem is particularly exacerbated in rivers and reservoirs situated in developing nations. Therefore, the objective of this study was to evaluate the potential contamination effects of illegal gold mining activities on freshwater Potamonautid crabs and to quantify the mercury levels in 49 river sites under three land use classes: communal areas, national parks and timber plantations. We used a combination of field sampling, multivariate analysis and geospatial tools to quantify mercury concentrations in relation to crab abundances. Illegal mining was prevalent throughout the three land use classes, with mercury (Hg) being detected in 35 sites (71.5 %). The mean range of Hg concentrations detected across the three-land uses was: communal areas 0-0.1 mg kg-1, national parks 0-0.3 mg kg-1 and timber plantations 0-0.06 mg kg-1. Mean Hg geo-accumulation index values showed strong to extreme contamination in the national park, with strong contamination observed for communal areas and timber plantations; furthermore, the enrichment factor for Hg concentrations in the communal and national park areas showed extremely high enrichment. Two crab species (i.e., Potamonautes mutareensis, Potamonautes unispinus) were found in the Chimanimani area, with P. mutareensis being the dominant taxon in the region across all the three land use areas. The national parks had higher total crab abundances than communal and timber plantation areas. We observed negative and significant K, Fe, Cu and B effects on total Potamonautid crab abundances, but surprisingly not for other metals such as Hg which might reflect their widespread pollution. Thus, illegal mining was observed to impact the river system, having a serious impact on the crab abundance and habitat quality. Overall, the findings of this study underscores the need to address the issue of illegal mining within the developing world as well as to establish concerted effort from all stakeholders (e.g., government, mining companies, local communities, and civil society groups) to help protect the less charismatic and understudied taxa. In addition, addressing illegal mining and protecting understudied taxa aligns with the SDGs (e.g. SDG 14/15-life below water/life on land) and contributes to global efforts to safeguard biodiversity and promote sustainable development.

Microplastic abundance, distribution, and diversity in water and sediments along a subtropical river system.

Microplastic pollution in aquatic environments has been a ubiquitous concern in recent years, owing to their rapid production combined with poor waste management practices. However, information on freshwater microplastics in the Global South is still scarce, despite growing research on freshwater microplastics in recent years, particularly within the Global North. To help address this knowledge gap, we studied water and sediment microplastic dynamics along a subtropical river system, i.e. Crocodile River around the Nelspruit City area (South Africa), across three different seasons (i.e. cool-dry, hot-dry, hot-wet) using a combination of diversity indices and multivariate analyses. Microplastics were more abundant during the cool-dry season in the surface water samples (mean 1058 particles m-3) and high during the hot-dry season (mean 568 particles kg-1 dwt) in the sediment samples. The hot-wet season had a low particle density in both surface water (mean 625 particles m-3) and sediments (mean 86 particles kg-1 dwt) samples. Microplastic shapes were dominated by fibres and fragments, with the colour scheme dominated by transparent, blue, and black. The abundance of microplastics was positively correlated with pH and resistivity, and negatively with river flow. Wastewater was attributed as a primary source of microplastics, particularly because of the observed dominant fibre microplastics, usually released during laundry. Our results suggest that Crocodile River and its tributaries are temporary sinks of microplastics during periods of low rainfall. Implications of this pollution are far-reaching, including effects on residents who are dependent on the Crocodile River as a source of drinking water and aquatic biota which may be exposed to these pollutants.

Underexplored and growing economic costs of invasive alien trees.

The high ecological impacts of many invasive alien trees have been well documented. However, to date, we lacked synthesis of their economic impacts, hampering management actions. Here, we summarize the cost records of invasive trees to (I) identify invasive trees with cost information and their geographic locations, (II) investigate the types of costs recorded and sectors impacted by invasive trees and (III) analyze the relationships between categories of uses of invasive trees and the invasion costs attributed to these uses. We found reliable cost records only for 72 invasive trees, accumulating a reported total cost of $19.2 billion between 1960 and 2020. Agriculture was the sector with the highest cost records due to invasive trees. Most costs were incurred as resource damages and losses ($3.5 billion). Close attention to the ornamental sector is important for reducing the economic impact of invasive trees, since most invasive trees with cost records were introduced for that use. Despite massive reported costs of invasive trees, there remain large knowledge gaps on most invasive trees, sectors, and geographic scales, indicating that the real cost is severely underestimated. This highlights the need for further concerted and widely-distributed research efforts regarding the economic impact of invasive trees.

Unveiling the hidden economic toll of biological invasions in the European Union.

Background: Biological invasions threaten the functioning of ecosystems, biodiversity, and human well-being by degrading ecosystem services and eliciting massive economic costs. The European Union has historically been a hub for cultural development and global trade, and thus, has extensive opportunities for the introduction and spread of alien species. While reported costs of biological invasions to some member states have been recently assessed, ongoing knowledge gaps in taxonomic and spatio-temporal data suggest that these costs were considerably underestimated. Results: We used the latest available cost data in InvaCost (v4.1)-the most comprehensive database on the costs of biological invasions-to assess the magnitude of this underestimation within the European Union via projections of current and future invasion costs. We used macroeconomic scaling and temporal modelling approaches to project available cost information over gaps in taxa, space, and time, thereby producing a more complete estimate for the European Union economy. We identified that only 259 out of 13,331 (~ 1%) known invasive alien species have reported costs in the European Union. Using a conservative subset of highly reliable, observed, country-level cost entries from 49 species (totalling US$4.7 billion; 2017 value), combined with the establishment data of alien species within European Union member states, we projected unreported cost data for all member states. Conclusions: Our corrected estimate of observed costs was potentially 501% higher (US$28.0 billion) than currently recorded. Using future projections of current estimates, we also identified a substantial increase in costs and costly species (US$148.2 billion) by 2040. We urge that cost reporting be improved to clarify the economic impacts of greatest concern, concomitant with coordinated international action to prevent and mitigate the impacts of invasive alien species in the European Union and globally. Supplementary Information: The online version contains supplementary material available at 10.1186/s12302-023-00750-3.

Long-term trends in abundances of non-native species across biomes, realms, and taxonomic groups in Europe.

Rates of biological invasion have increased over recent centuries and are expected to increase in the future. Whereas increasing rates of non-native species incursions across realms, taxonomic groups, and regions are well-reported, trends in abundances within these contexts have lacked analysis due to a paucity of long-term data at large spatiotemporal scales. These knowledge gaps impede prioritisation of realms, regions, and taxonomic groups for management. We analysed 180 biological time series (median 15 ± 12.8 sampling years) mainly from Long-Term Ecological Research (LTER) sites comprising abundances of marine, freshwater, and terrestrial non-native species in Europe. A high number (150; 83,3 %) of these time series were invaded by at least one non-native species. We tested whether (i) local long-term abundance trends of non-native species are consistent among environmental realms, taxonomic groups, and regions, and (ii) if any detected trend can be explained by climatic conditions. Our results indicate that abundance trends at local scales are highly variable, with evidence of declines in marine and freshwater long-term monitoring sites, despite non-native species reports increasing rapidly since the late 1970s. These declines were driven mostly by abundance trends in non-native fish, birds, and invertebrate species in three biogeographic regions (Continental, Atlantic, and the North Sea). Temperature and precipitation were important predictors of observed abundance trends across Europe. Yet, the response was larger for species with already declining trends and differed among taxa. Our results indicate that trends in biological invasions, especially across different taxonomic groups, are context-dependent and require robust local data to understand long-term trends across contexts at large scales. While the process of biological invasion is spatiotemporally broad, economic or ecological impacts are generally realised on the local level. Accordingly, we urge proactive and coordinated management actions from local to large scales, as invasion impacts are substantial and dynamics are prone to change.

Limited Effect of Ground Floor Fogging on Mosquito Distribution in High-Rise Condominia.

Fogging with insecticides is one of the main control measures for adult mosquito populations employed in countries that are affected by dengue. In many such countries, urban communities are increasingly characterised by high-density residence in high-rise condominia. Although fogging is typically applied at the ground level, its efficacy in three-dimensional urban environments is poorly understood. Here, we investigated the effect of fogging on vector mosquito distribution and abundance in high-rise condominia by conducting a before-after fogging survey. We showed that although mosquitoes were significantly concentrated at the lower levels in high-rise condominia, they were found throughout the three-dimensional environments. Fogging did not significantly alter this distribution or abundance pattern across any floor level. Thus, any fogging effect was short-lived as mosquito populations recovered within a few days before the subsequent scheduled treatment. In addition, increasing fogging frequency within practicable limits did not prolong the intended control effect. As urban mosquitoes are increasingly insusceptible to fogging due to insecticide resistance and vertical avoidance, this study demonstrates the need to implement other mosquito control strategies for high-rise condominia to manage mosquito populations.

Resilient amphipods: Gammarid predatory behaviour is unaffected by microplastic exposure and deoxygenation.

Microplastics are a ubiquitous and persistent form of pollution globally, with impacts cascading from the cellular to ecosystem level. However, there is a paucity in understanding interactions between microplastic pollution with other environmental stressors, and how these could affect ecological functions and services. Freshwater ecosystems are subject to microplastic input from anthropogenic activities (eg. wastewater), but are also simultaneously exposed to many other stressors, particularly reduced dissolved oxygen availability associated with climatic warming and pollutants, as well as biological invasions. Here, we employ the comparative functional response method (CFR; quantifying and comparing organism resource use as a function of resource density) to investigate the relative impact of different microplastic concentrations and oxygen regimes on predatory trophic interactions of a native and an invasive alien gammarid (Gammarus duebeni and Gammarus pulex). No significant effect on trophic interaction strengths was found from very high concentrations of microplastics (200 mp/L and 200,000 mp/L) or low oxygen (40 %) stressors on either species. Additionally, both gammarid species exhibited significant Type II functional responses, with attack rates and handling times not significantly affected by microplastics, oxygen or gammarid invasion status. Thus, both species showed resistance to the simultaneous effects of microplastics and deoxygenation in terms of feeding behaviour. Based on these findings, we suggest that the trophic function, in terms of predation rate, of Gammarus spp. may be sustained under acute bouts of microplastic pollution even in poorly­oxygenated waters. This is the first study to investigate microplastic and deoxygenation interactions and to find no evidence for an interaction on a key invertebrate ecosystem service. We argue that our CFR methods can help understand and predict the future ecological ramifications of microplastics and other stressors across taxa and habitats.