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Understanding the strength, direction and consequences of the trophic impacts of invasive fish on functionally analogous native fishes is important in invasion impact assessment and for informing management programmes. As functionally analogous native and invasive fishes can share prey resources, there is high potential for competitive interactions, which could affect trophic niche sizes and positions.The highly invasive mrigal carp Cirrhinus mrigala and native mud carp Cirrhinus molitorella now co‐exist in many freshwaters in southern China, raising concern on the consequences for mud carp. The trophic interactions of the two species and their consequences (for growth rates and trophic niche sizes as the isotopic niche, calculated using δ13C and δ15N) were tested in a pond enclosure experiment based on additive and substitutive treatments using fish in allopatric and sympatric contexts, with results compared with invaded wild communities.In the experiment, specific growth rates decreased significantly as fish abundance in treatments increased. These density‐dependent effects were observed in both species and were independent of whether the treatment was allopatric or sympatric. In allopatric treatments, isotopic niches of mud carp increased in size with fish number. Conversely, in sympatric treatments, mud carp isotopic niche size decreased with increased mrigal carp number. For mrigal carp, isotopic niche sizes decreased as fish number increased in both allopatric and sympatric treatments.In sympatric experiment treatments, the isotopic niches of mud carp and mrigal carp were always divergent. This was, however, in contrast to four invaded wild communities, where the isotopic niches of the two fishes always had some overlap.Experimental and field data suggest that although native mud carp could be impacted by mrigal carp, these impacts might only manifest when the species are at very high abundances and inter‐specific competitive interactions could be intense. These results also suggest the two species have mechanisms that reduce their inter‐specific interactions to minimise their competitive interactions, thus any ecological impacts from mrigal carp might manifest more from indirect than direct processes. [ABSTRACT FROM AUTHOR]

Freshwater ecosystems are threatened by the introduction of invasive species. Generalist invaders often compete with native species for shared resources, resulting in possible native species niche displacement. However, environmental heterogeneity may modulate the level of individual specialisation in invasive species, altering the outcome of interspecific competition between invasive and native species. The objectives of our study were to (1) evaluate the environmental context of dietary specialisation and trophic position of an invasive species according to the Environmental Matching Hypothesis (EMH), and (2) consider how the environmental context of invasive species dietary resource use may influence the dietary niche of native species competing for similar resources.Resource use, trophic position and dietary niche were determined using gut content and stable isotope analyses for the invasive round goby (Negobius melanostomus) and the native yellow perch (Perca flavescens), along environmental gradients in an invaded fluvial ecosystem.Our results were in support of EMH for the invader diet and resource specialisation, but not trophic position. Under environmental conditions of high water‐conductivity, round gobies were generalists feeding mostly on pelagic prey. Under more challenging environmental conditions of low water‐conductivity, the invader specialised on preferred high‐quality benthic prey. The ecological impact of the round goby was greatest at low water‐conductivity sites where the invader was a benthic specialist; there was a greater relative dietary niche overlap between the invader and the native species.Our study uniquely illustrates how invasive species' resource specialisation can be modulated by spatial environmental heterogeneity within ecosystems, and how this can subsequently alter the ecological impact of the invader on native species in aquatic food webs. [ABSTRACT FROM AUTHOR]

Aim: Invasions of non‐native insects can have substantial impacts on agriculture, forestry, human health and biodiversity with considerable economic and environmental consequences. To understand the causes of these invasions, it is important to quantify the relative influence of principal drivers such as international imports and climatic effects. Location: North America, Chile, Europe, Australia, New Zealand and Japan. Time Period: 1881–2020. Methods: To evaluate the relative contributions of various factors in explaining global variation in numbers of non‐native insect establishments in different world regions, we conducted two multivariate regression analyses to quantify temporal changes in family‐level composition and native ranges of established non‐native species in several world regions. Results: There were temporal changes in the family‐level composition of non‐native species assemblages. Prior to 1900, invasions were dominated by scale insects, subsequently shifting to a more diverse set of species, except in North America, which had relatively small compositional change over time compared to other regions. Spatial and temporal variation in the composition of established species was associated with differences in the origin of imports and climatic factors, each explaining 26.3% and 27.4% of the total variation, respectively. The analysis of native ranges of non‐native species indicated that there was no consistent temporal variation across all regions. Established species in New Zealand were predominantly native to Australasia and species in North America and Chile were mainly from Europe. Non‐native species in Europe mainly originated from the Nearctic region while those in Japan and Australia generally originated from multiple regions. Climatic factors in the destination regions had a primary effect (66.3%) on variation in the native range of established species, although imports also had substantial effects (45.4%). Main Conclusions: Geographical variation in climate and imports act together as drivers of establishment success for non‐native insects in all six regions. [ABSTRACT FROM AUTHOR]

Aim: Retrospective (pre‐ vs. post‐invasion) and cross‐sectional comparisons of ecosystems exposed to high and low bioinvasion pressure, provide an alternative approach to evaluate shifts in biological communities associated with non‐indigenous species (NIS) introductions. In this study, we aimed to examine general patterns of change in community composition, structure and function in six well‐studied and globally distributed marine ecosystems that had documented histories of biological invasions. Location: Global. Methods: By considering a range of regional datasets and different sampling approaches, we evaluated trends within and among ecosystems by comparing paired measures of community and functional structure in either space or time. Results: Our analyses revealed different patterns of structural and functional change at ecosystem scales, but direct comparisons across regions were hindered by confounding effects of study designs and other drivers of change. The most prominent shifts in community composition were observed in the retrospective studies, characterised by the greatest relative contribution of NIS. No uniform pattern of change in functional metrics was observed across study regions. However, functional evenness and dispersion showed a tendency to increase in systems under higher invasion pressure, refuting the hypothesis of selective accumulation of specific traits and functional homogenisation within ecosystems exposed to high invasion pressure. Main Conclusions: Accumulation of NIS within broader communities can be a subtle process, with inherent spatial and temporal variability. Nonetheless, not only do species' proportional contributions to communities change over time in areas subjected to high bioinvasion pressure, but trait profiles can incrementally shift, which alters the original ecology of an area. Planned, long‐term studies that incorporate a range of measures of environmental drivers and ecosystem response are crucial for better understanding of cumulative, community‐level and ecosystem‐scale change associated with biological invasions. [ABSTRACT FROM AUTHOR]

Aim: Although non‐native and invasive plants often pose a significant threat to biodiversity, global‐scale studies have yet to conclusively demonstrate a systematic pattern of reduced native plant diversity in areas affected by these invasions. Here, we aim to explore the association of non‐native and invasive plants with the species richness and evenness of plant communities from the local to global scale. Location: Global. Methods: We use the world's largest vegetation plot repository—sPlot—to compare species richness and community evenness between invaded (by invasive or non‐natives) and native plots of equal size, paired within 32 km2 grid cells distributed across all continents. Aggregating plots at the cell, biome and global level, we also quantified differences in gamma diversity at different spatial scales. Results: We found that invaded plots had higher species richness and similar community evenness, a trend largely consistent across biomes. The higher total species richness was not the result of additional invasive or non‐native species, as the number of native species was also higher in invaded plots. These patterns persisted at larger spatial scales. Cell, biome and global gamma species richness of invaded plots were consistently higher than of native plots. All these patterns held regardless of whether the non‐native species in a plot were invasive or non‐invasive. Main Conclusions: Our study reveals a globally consistent pattern: plant diversity, both total and native, is higher when invasive or non‐native plants are present, spanning spatial scales from local to global. Although we cannot infer causal effects, our results challenge the prevailing hypothesis that non‐native and invasive species universally depress plant diversity. [ABSTRACT FROM AUTHOR]

Heterospecific sociability could enhance invasion success in social species since social non‐natives usually belong to small founding populations during the early stages of invasion. The twospot livebearer (Pseudoxiphophorus bimaculatus) is native to Central America and southern Mexico and is recently recognised as invasive in the Mexican Central Plateau, where it poses a threat to native species. Here, we evaluated twospot livebearer sociability towards either a conspecific pair or a shoal of four fish with one of four possible compositions, all conspecifics or two conspecifics combined with either two guppies, two porthole livebearers or two twoline skiffias. In a second experiment, foraging time, latency to feed, first fish to begin foraging and aggressive interactions were recorded under the same social conditions used in the sociability experiment, with body size included as a covariate in both experiments. All focal twospot livebearers spent significantly more time with the given shoals rather than with the available space in the aquarium. They showed a higher tendency to associate with small shoals of conspecifics than with pairs. Larger twospot livebearers associated more, regardless of the social condition. Twospot livebearer fed more with porthole livebearers, less with guppies and similarly with twoline skiffias. Latency to forage did not vary significantly between social conditions. Twospot livebearers were involved in more aggressive interactions when with guppies or porthole livebearers than when with native twoline skiffias or conspecifics. Twospot livebearers could gain benefits from associating with natives and conspecifics, but not with other invasive poeciliids. Heterospecific shoaling behaviour with natives may enhance invasion success during early stages when conspecifics are scarce while associating with other invasive poeciliids could lead to increased competition. Further research is needed on heterospecific interactions of non‐natives to better understand their behavioural role in invasion likelihood. [ABSTRACT FROM AUTHOR]

The presence of alien species represents a major cause of habitat degradation and biodiversity loss worldwide, constituting a critical environmental challenge of our time. Despite sometimes experiencing reduced propagule pressure, leading to a reduced genetic diversity and an increased chance of inbreeding depression, alien invaders are often able to thrive in the habitats of introduction, giving rise to the so‐called "genetic paradox" of biological invasions. The adaptation of alien species to the new habitats is therefore a complex aspect of biological invasions, encompassing genetic, epigenetic, and ecological processes. Albeit numerous studies and reviews investigated the mechanistic foundation of the invaders' success, and aimed to solve the genetic paradox, still remains a crucial oversight regarding the temporal context in which adaptation takes place. Given the profound knowledge and management implications, this neglected aspect of invasion biology should receive more attention when examining invaders' ability to thrive in the habitats of introduction. Here, we discuss the adaptation mechanisms exhibited by alien species with the purpose of highlighting the timing of their occurrence during the invasion process. We analyze each stage of the invasion separately, providing evidence that adaptation mechanisms play a role in all of them. However, these mechanisms vary across the different stages of invasion, and are also influenced by other factors, such as the transport speed, the reproduction type of the invader, and the presence of human interventions. Finally, we provide insights into the implications for management, and identify knowledge gaps, suggesting avenues for future research that can shed light on species adaptability. This, in turn, will contribute to a more comprehensive understanding of biological invasions. [ABSTRACT FROM AUTHOR]

Biological invasion consists of spatially and temporally varying stages, accompanied by ecological and evolutionary changes. Understanding the genomics underlying invasion dynamics provides critical insights into the geographic sources and genetic diversity, contributing to successful invasions across space and time. Here, we used genomic data and model‐based approaches to characterize the invasion dynamics of Hypochaeris radicata L., a noxious weed in Korea. Genetic diversity and assignment patterns were investigated using 3563 SNPs of 283 individuals sampled from 22 populations. We employed a coalescent‐based simulation method to estimate demographic changes for each population and inferred colonization history using both phylogenetic and population genetic model‐based approaches. Our data suggest that H. radicata has been repeatedly been introduced to Korea from multiple genetic sources within the last 50 years, experiencing weak population bottlenecks followed by subsequent population expansions. These findings highlight the potential for further range expansion, particularly in the presence of human‐mediated dispersal. Our study represents the first population‐level genomic research documenting the invasion dynamics of the successful worldwide invader, H. radicata, outside of Europe. [ABSTRACT FROM AUTHOR]

Predicting the risk of establishment and spread of populations outside their native range represents a major challenge in evolutionary biology. Various methods have recently been developed to estimate population (mal)adaptation to a new environment with genomic data via so‐called Genomic Offset (GO) statistics. These approaches are particularly promising for studying invasive species but have still rarely been used in this context. Here, we evaluated the relationship between GO and the establishment probability of a population in a new environment using both in silico and empirical data. First, we designed invasion simulations to evaluate the ability to predict establishment probability of two GO computation methods (Geometric GO and Gradient Forest) under several conditions. Additionally, we aimed to evaluate the interpretability of absolute Geometric GO values, which theoretically represent the adaptive genetic distance between populations from distinct environments. Second, utilizing public empirical data from the crop pest species Bactrocera tryoni, a fruit fly native from Northern Australia, we computed GO between "source" populations and a diverse range of locations within invaded areas. This practical application of GO within the context of a biological invasion underscores its potential in providing insights and guiding recommendations for future invasion risk assessment. Overall, our results suggest that GO statistics represent good predictors of the establishment probability and may thus inform invasion risk, although the influence of several factors on prediction performance (e.g., propagule pressure or admixture) will need further investigation. [ABSTRACT FROM AUTHOR]

A branch of island biogeography has emerged to explain alien species diversity in the light of the biogeographic and anthropogenic context, yet overlooking the functional and phylogenetic facets. Evaluating alien and native birds of 407 oceanic islands worldwide, we built structural equation models to assess the direct and indirect influence of biotic, geographic, and anthropogenic contexts on alien functional diversity (FD) and phylogenetic diversity (PD). We found that alien taxonomic richness was the main predictor of both diversities. Anthropogenic factors, including colonization pressure, associated with classic biogeographical variables also strongly influenced alien FD and PD. Specifically, habitat modification and human connectivity markedly drove alien FD, especially when controlled by taxonomic richness, whereas the human population size, gross domestic product, and native PD were crucial at explaining alien PD. Our findings suggest that humans not only shape taxonomic richness but also other facets of alien diversity in a complex way. [ABSTRACT FROM AUTHOR]

Native parasitoids are potential tools for the biological control of invasive exotic pests, such as the frugivorous flies spotted‐wing drosophila, Drosophila suzukii Matsumura, and African fig fly, Zaprionus indianus Gupta (both Diptera: Drosophilidae). Following biological invasions, the establishment of exotic species may be restricted, among other things, by their susceptibility to native or established natural enemies. The Neotropical‐native pupal endoparasitoid Trichopria anastrephae Costa Lima (Hymenoptera: Diapriidae), although primarily associated with hosts of the genus Anastrepha (Tephritidae), has also been described to attack Drosophilidae. There are few studies on the interaction between parasitoids native to Argentina and D. suzukii and/or Z. indianus. The present work evaluates the parasitism of T. anastrephae on both species of drosophilids under controlled conditions. Ten larvae (L3) of each host species were exposed separately to a couple of adult T. anastrephae for 72 h (n = 10). For both control and parasitoid treatment, 10 larvae (L3) of D. suzukii and Z. indianus were placed in 10 flasks (repetition) at the L3 stage. Host emergence, the infestation degree index (DI), and the parasitism success rate (SP) were calculated. Drosophila suzukii and Z. indianus emergence differed significantly in controlled conditions being 41% higher for Z. indianus than for D. suzukii. The DI was 100% in D. suzukii and 38% in Z. indianus, and the SP was 48% both in D. suzukii and in Z. indianus. These findings indicate that the native parasitoid T. anastrephae has a high potential as a biocontrol strategy against D. suzukii. In addition, the efficiency of T. anastrephae against Z. indianus, an invasive frugivorous widely spread in the Neotropical region, was evaluated for the first time. [ABSTRACT FROM AUTHOR]

Coccinellids (Coleoptera) are important natural enemies of pests in agroecosystems. However, worldwide, native species face several threats, including landscape simplification, biological invasions, and climate change. In Central Chile, one of the global biodiversity hotspots, coccinellid communities are very diverse and are composed mostly of native species, which are most common in less disturbed habitats. In alfalfa fields, native coccinellids play a crucial role in the biological control of aphids, even when they are less abundant than exotics. However, in the last 2 decades, native species in this crop have declined in abundance and diversity. Our long‐lasting field and laboratory studies have shown that this decline is associated with: (1) the invasion of Harmonia axyridis (Pallas), which has superior competitive abilities and escapes more from parasitism; (2) the simplification of agricultural landscapes, loss of natural habitats, and urbanization; and (3) increasing environmental temperatures and decreasing precipitation. The decline in native coccinellid populations has resulted in a loss of taxonomic and functional diversity of assemblages, which may jeopardize biological control. Alfalfa fields and natural and semi‐natural habitats may offer an opportunity for the conservation of native coccinellids in agricultural landscapes. Such conservation might be achieved with better management of alfalfa fields and surrounding areas. [ABSTRACT FROM AUTHOR]

Predation is a dominant structuring force in ecological communities. In aquatic environments, predation on bivalves has long been an important focal interaction for ecological study because bivalves have central roles as ecosystem engineers, basal components of food webs, and commercial commodities. Studies of bivalves are common, not only because of bivalves' central roles, but also due to the relative ease of studying predatory effects on this taxonomic group. To understand patterns in the interactions of bivalves and their predators we synthesised data from 52 years of peer‐reviewed studies on bivalve predation. Using a systematic search, we compiled 1334 studies from 75 countries, comprising 61 bivalve families (N = 2259), dominated by Mytilidae (29% of bivalves), Veneridae (14%), Ostreidae (8%), Unionidae (7%), and Dreissenidae and Tellinidae (6% each). A total of 2036 predators were studied, with crustaceans the most studied predator group (34% of predators), followed by fishes (24%), molluscs (17%), echinoderms (10%) and birds (6%). The majority of studies (86%) were conducted in marine systems, in part driven by the high commercial value of marine bivalves. Studies in freshwater ecosystems were dominated by non‐native bivalves and non‐native predator species, which probably reflects the important role of biological invasions affecting freshwater biodiversity. In fact, while 81% of the studied marine bivalve species were native, only 50% of the freshwater species were native to the system. In terms of approach, most studies used predation trials, visual analysis of digested contents and exclusion experiments to assess the effects of predation. These studies reflect that many factors influence bivalve predation depending on the species studied, including (i) species traits (e.g. behaviour, morphology, defence mechanisms), (ii) other biotic interactions (e.g. presence of competitors, parasites or diseases), and (iii) environmental context (e.g. temperature, current velocity, beach exposure, habitat complexity). There is a lack of research on the effects of bivalve predation at the population and community and ecosystem levels (only 7% and 0.5% of studies respectively examined impacts at these levels). At the population level, the available studies demonstrate that predation can decrease bivalve density through consumption or the reduction of recruitment. At the community and ecosystem level, predation can trigger effects that cascade through trophic levels or effects that alter the ecological functions bivalves perform. Given the conservation and commercial importance of many bivalve species, studies of predation should be pursued in the context of global change, particularly climate change, acidification and biological invasions. [ABSTRACT FROM AUTHOR]

Aim: Metabolic rate is a widely studied physiological species trait related to energetics, climate, and geographical distributions. Hypotheses have been proposed to explain variation in metabolic rate, but evidence has been mixed due to the limited sampling scope of intraspecific studies. Successful biological invasions offer a unique opportunity to examine the development of intraspecific physiological variation and how it relates to climate, invasive spread and species range limits. The aim of this study was to determine if metabolic rate variation across the spongy moth invasive range was consistent with a pattern of adaptation to local climate. Location: Northeastern United States of America. Taxon: Lymantria dispar dispar L. (Lepidoptera: Erebidae). Methods: Larvae were sourced from 14 populations across the invasion front and interior of the current L. d. dispar invasive range and were reared at a constant temperature. Routine metabolic rates (RMR) of larvae were assayed at three ecologically relevant temperatures. These data were analysed to determine if there were differences in RMR and temperature sensitivity of RMR among populations. Population‐level variation in RMR was then analysed as a function of local climate and geographical position to test for patterns consistent with local adaptation. Results: Larval RMR showed significant variation among populations across all assay temperatures, but there was no difference in temperature sensitivity (i.e. slope). This variation followed a positive latitudinal cline with RMR increasing from the southern range to the north. This cline also showed a significant relationship with local climate variables. Main Conclusions: Larval metabolic rate variation was consistent with a pattern of adaptation by L. d. dispar to divergent climates across its invasive range. These results indicated that thermal adaptation of whole‐organism physiology may play a key role in promoting species spread and expansion for biological invasions like L. d. dispar. [ABSTRACT FROM AUTHOR]

Aim: Darwin posited that invaders similar to native species are less likely to be successful due to competitive exclusion. A key axis across which such competition occurs across angiosperms is the timing of flowering, or reproductive phenology. It has been hypothesized that temporal isolation facilitates the establishment of introduced species. However, our knowledge of how the timing of flowering may influence invasion success is lacking at broader geographic and larger taxonomic scales. To address this impasse, we investigated: (i) how flowering phenology differs between native and non‐native species; (ii) whether the flowering phenology of successful invaders is distinct from native taxa; and (iii) whether invasive species tend to be more closely related to natives than other less successful, non‐invasive introduced species are. Location: California, USA. Time Period: Present. Major Taxa Studied: Angiosperms. Methods: We compiled phenological data for over 6000 angiosperm species across California, a highly invaded biodiversity hotspot, from published flora. Using these data, we assessed the degree of phenological and phylogenetic similarity among native, non‐invasive introduced, and invasive species. We also examined how this similarity varies with climate. Results: Both non‐invasive introduced and invasive species were more phenologically and phylogenetically distant from natives than natives were from each other. However, invasive plants tend to be more similar to native species in terms of flowering phenology and phylogenetic relationships than non‐invasive introduced species. Further, the degree of similarity between native and non‐native species was mediated by climate, where phenological and phylogenetic similarities were greater in cooler regions. Main Conclusions: Together, our results demonstrate that both similarity and distinctiveness can facilitate plant invasions and that invaders just similar enough to the native flora are more likely to be successful. [ABSTRACT FROM AUTHOR]

Via sheltering, decoupling and buffering mechanisms, tree canopies have the capacity to mitigate impacts of multiple global‐change drivers on below‐canopy processes and organisms in forests. As a result, canopies have an important potential as nature‐based solution. The optimal combinations of forest canopy structural attributes to jointly mitigate the impacts of multiple global‐change drivers on below‐canopy organisms and processes have received little attention to date. To help solving this research gap, here we review how forest canopies modulate the effects of four important global‐change drivers—climate warming, drought, air pollution and biological invasions—on below‐canopy conditions. Particular attention is paid to mitigating canopy attributes that can be influenced by forest management, including canopy cover, tree species composition and vertical and horizontal structure. Synthesis. We show that the potential of forest canopies to mitigate global‐change effects is highly context‐dependent and that optimal canopy‐based solutions strongly depend on the environmental context and the targeted subcanopy organisms. Hence, holistic approaches, which maximize synergies and minimize trade‐offs, are needed to optimize the solution potential of forest canopies. [ABSTRACT FROM AUTHOR]

Aim Innovation Main conclusion Reducing the rate of alien species introductions is a major conservation aim. However, accurately quantifying the rate at which species are introduced into new regions remains a challenge due to the confounding effect of observation efforts on discovery records. Despite the recognition of this issue, most analyses are still based on raw discovery records, leading to biased inferences. In this study, we evaluate different models for estimating introduction rates, including new models that use auxiliary data on observation effort, and identify their strengths and weaknesses.We compare four models: (1) a naïve model which assumes perfect detection; (2) a model proposed by Solow and Costello (the S&C model); (3) constant detection model: a modified version of the S&C model with constant detection probabilities and (4) a novel sampling proxy model: a model that uses external data on observation effort. We simulate discovery records of varying lengths, introduction rates and temporal patterns of detection probabilities to explore scenarios under which these models accurately estimate underlying introduction rates. (5) We also include code to perform a model based on Belmaker using independent data on the number of native species.We found that the length of the discovery records and the annual number of recorded species play a crucial role in the performance of all models. Under simulated scenarios of high detection, the naïve model is usually the best‐performing model, but it falls short when detection is low. Moreover, we find that in simulations which most likely mimic most real‐world cases (i.e. non‐monotonic probability of detection), incorporating external data on observation effort using the sampling proxy model, substantially improve estimates. This highlights the importance of considering observation effort when estimating introduction rates of alien species. To facilitate the use of these models, we provide a decision workflow and a dedicated R package (‘alien’). [ABSTRACT FROM AUTHOR]

Research conducted during the past two decades has demonstrated that biological invasions are excellent models of rapid evolution. Even so, characteristics of invasive populations such as a short time for recombination to assemble optimal combinations of alleles may occasionally limit adaptation to new environments. Here, we investigated such genetic constraints to adaptation in the invasive brown anole (Anolis sagrei)—a tropical ectotherm that was introduced to the southeastern United States, a region with a much colder climate than in its native Caribbean range. We examined thermal physiology for 30 invasive populations and tested for a climatic cline in cold tolerance. Also, we used genomics to identify mechanisms that may limit adaptation. We found no support for a climatic cline, indicating that thermal tolerance did not shift adaptively. Concomitantly, population genomic results were consistent with the occurrence of recombination cold spots that comprise more than half of the genome and maintain long‐range associations among alleles in invasive populations. These genomic regions overlap with both candidate thermal tolerance loci that we identified using a standard genome‐wide association test. Moreover, we found that recombination cold spots do not have a large contribution to population differentiation in the invasive range, contrary to observations in the native range. We suggest that limited recombination is constraining the contribution of large swaths of the genome to adaptation in invasive brown anoles. Our study provides an example of evolutionary stasis during invasion and highlights the possibility that reduced recombination occasionally slows down adaptation in invasive populations. [ABSTRACT FROM AUTHOR]

Summary: Research on mycorrhizal symbiosis has been slowed by a lack of established study systems. To address this challenge, we have been developing Suillus, a widespread ecologically and economically relevant fungal genus primarily associated with the plant family Pinaceae, into a model system for studying ectomycorrhizal (ECM) associations. Over the last decade, we have compiled extensive genomic resources, culture libraries, a phenotype database, and protocols for manipulating Suillus fungi with and without their tree partners. Our efforts have already resulted in a large number of publicly available genomes, transcriptomes, and respective annotations, as well as advances in our understanding of mycorrhizal partner specificity and host communication, fungal and plant nutrition, environmental adaptation, soil nutrient cycling, interspecific competition, and biological invasions. Here, we highlight the most significant recent findings enabled by Suillus, present a suite of protocols for working with the genus, and discuss how Suillus is emerging as an important model to elucidate the ecology and evolution of ECM interactions. [ABSTRACT FROM AUTHOR]

Question: How does the diversity of successional forests evolve with stand age, and to what extent do permanent plots validate the previously studied successional patterns of tree diversity and composition observed through chronosequences? To evaluate the role of successional forests as reservoirs for many species, it is essential to examine how biodiversity recovers with the age of the stand. We studied patterns of taxonomic and functional diversity, as well as species composition during forest succession, by combining chronosequences and permanent plot monitoring. Location: Subtropical montane forests in NW Argentina. Methods: We used data from two chronosequences of plots monitored for 30 years in lower and upper montane forests dominated by native trees (LMF‐Native and UMF‐Native), and one chronosequence of plots dominated by the exotic tree Ligustrum lucidum, monitored for 10 years in low montane forests (LMF‐Invaded). We analyzed changes in taxonomic (species richness, Shannon diversity, Simpson diversity) and functional diversity, as well as composition with forest age. Results: Taxonomic and functional diversity increased between 30 and 70 years of succession in LMF‐Native and UMF‐Native. Successional LMF‐Native forests reached the diversity of mature forests earlier than UMF‐Native. In LMF‐Invaded, taxonomic and functional diversity decreased in the same period because of the increasing dominance of the exotic species Ligustrum lucidum. In non‐invaded chronosequences (LMF‐Native and UMF‐Native) we observed a convergence towards the composition of mature forests; however, each successional forest kept its identity for 30 years. Conclusions: Diversity and composition followed different successional trajectories depending on the type of forest. We found that successional patterns, such as changes in taxonomic and functional diversity, predicted with the chronosequence approach, were confirmed with data from plot monitoring. The effects of pre‐abandonment conditions persist in the diversity and composition of successional forests monitored between 10 and 30 years. [ABSTRACT FROM AUTHOR]

Understanding how and why some species or lineages become invasive is critically important for effectively predicting and mitigating biological invasions. Here, we address an important unanswered question in invasion biology: do key life‐history traits of invasive versus native lineages within a species differ in response to key environmental stressors? We focus on the environmental factor of population density, which is a fundamental characteristic of all populations, and investigate how changes in density affect native versus invasive Potamopyrgus antipodarum (New Zealand mudsnail). P. antipodarum has invaded 39 countries and detrimentally affects invaded environments. Previous studies of native and invasive populations and from laboratory experiments have demonstrated that growth and reproduction of P. antipodarum is sensitive to population density, though whether and how this sensitivity varies across native versus invasive lineages remains uncharacterized. We quantified individual growth rate and reproduction in P. antipodarum from multiple distinct native and invasive lineages across three different population density treatments. The growth of native but not invasive lineages decreased as density increased. There was no differential effect of density treatment on embryo production of invasive versus native snails, but a significantly higher proportion of snails were reproductive in high density compared to intermediate density for invasive lineages. In native lineages, there were no significant differences in the relative frequency of reproductive snails across density treatments. While the extent to which these results from our laboratory study can be extrapolated to the more complex natural world remain unclear, our findings are consistent with a scenario where differential sensitivity to population density could help explain why some lineages become successful invaders. Our findings also align with previous studies that show that invasive P. antipodarum lineages exhibit a relatively wide range of tolerance to environmental stressors. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Invasive plants are often attacked by both introduced specialist and native generalist natural enemies in new ranges. Soil fertility can potentially alter the interactions of these natural enemies with native versus invasive plants in ways that have largely unexplored implications for biological invasions and biological control.A common garden experiment was conducted to compare the performance of an introduced specialist flea beetle, Agasicles hygrophila, and/or a native generalist nematode, Meloidogyne incognita, on invasive alligator weed, Alternanthera philoxeroides, and its native congener sessile joyweed, Alternanthera sessilis, under different levels of soil nitrogen (N) and phosphorus (P).At a relatively low or moderate N and P levels, the flea beetle and the nematodes were not significantly affected by each other. Under these conditions, alligator weed responded plastically by producing more branches and biomass, as well as longer stolons, in response to attack by the flea beetle and/or the nematode, compared to sessile joyweed responses to similar levels of damage. However, under a relatively high N and P levels, nematode infestations significantly reduced flea beetle damage on alligator weed, resulting in significantly greater above‐ and below‐ground biomass and longer stolons than plants without herbivory. In contrast, beetle herbivory significantly increased the level of nematode infestations on sessile joyweed, resulting in significantly fewer fine and coarse roots, and lower above‐ and below‐ground biomass compared to plants without herbivory.Synthesis and applications. Our findings illustrate the importance of soil fertility in mediating interactions between specialist biocontrol agents and native generalists on native versus invasive plants. High phenotypic plasticity seems to be an important attribute that contributes to the success of invasive plants like alligator weed in relatively nutrient‐poor environments. However, nutrient‐rich environments could potentially confer greater growth benefits on invasive plants than on native ones by changing herbivore–herbivore interactions on plants differently. There is a great need to fully investigate the direct and indirect interactions between biocontrol agents and generalists across food webs following classical biocontrol releases. Nutrient measurements of both soil and water bodies should also be incorporated into all stages of biocontrol programmes. [ABSTRACT FROM AUTHOR]

Invasive species pose serious threats to ecosystems. To reduce ecological and economic consequences of invasions, efforts are made to control invaders and evaluating the effects of such efforts is paramount. Lionfishes (Pterois volitans and Pterois miles) are native to the Indo‐Pacific Ocean and pose a major threat to local ecosystems in the invaded Atlantic and Mediterranean. Culling via spearfishing is a widespread measure to limit lionfish population size in invaded ranges. However, like most hunted fishes, lionfish alter their behavior after repeated culling, potentially decreasing the effectiveness of future culls. Previous studies on lionfish in the Caribbean have shown that lionfish are less bold after repeated culling. However, the impact of culling on lionfish in their newest invasive range, the Mediterranean, remains enigmatic. To determine the behavioral changes in response to culling in this second area of invasion, we tested for effects of culling on the behavior of lionfish in Cyprus, a region heavily impacted by the lionfish invasion in the Mediterranean. We compared the response of lionfish to an approaching free diver holding a metal pole (imitating a spear fisher) between protected areas where spearfishing is restricted and areas where culls are frequently conducted. We also assessed whether activity, hiding pattern, and site fidelity differed between these culled and unculled sites. Overall, we found limited effects of culling on the traits measured, indicating surprising resistance to culling‐induced behavioral changes in Mediterranean lionfish. Future studies should monitor invasive lionfish population densities and the effects of culling in more detail to tailor management plans and reduce the negative effects of these fish in specific invaded ranges. [ABSTRACT FROM AUTHOR]

There is a long history of humans either intentionally or accidentally moving plant species to areas outside of their native ranges. In novel environments, populations of many of these plant species exhibit explosive population growth and spread, in part due to the absence of coevolved enemies such as herbivorous insects. However, over time such enemies can 'catch up' with their host and re‐establish host–herbivore relationships. Though this phenomenon has been documented in several systems, little evidence exists on how this re‐assembly of enemies results in increased levels of herbivory. In this study we focus on the case of black locust Robinia pseudoacacia, a sparsely populated tree species when growing on undisturbed sites in its limited native range in the eastern USA but a highly invasive species, especially in disturbed environments, in most temperate world regions. We recorded folivore damage on invasive populations in five continents, including both native and invaded portions of North America. Here, we investigated 1) how total foliage damage and damage caused by different groups of folivores differs among regions; 2) how seasonal development of folivore damage differs among regions; 3) how folivory varies with distance from the native range within North America; and 4) how the number of recorded specialist folivores correlates with the amount of folivory. We observed strong differences among regions in the amount and type of folivore damage, with the native range experiencing the highest damage, especially that caused by the native chrysomelid beetle Odontota dorsalis, which is limited to the native and invaded North American range of R. pseudoacacia. Among world regions, total folivory is negatively associated with the distance from the native range and positively associated with the number of established R. pseudoacacia specialist folivore species, supporting the hypothesis that global patterns of herbivore invasions are associated with diminished enemy release. [ABSTRACT FROM AUTHOR]

The Mediterranean Basin has historically been subject to alien plant invasions that threaten its unique biodiversity. This seasonally dry and densely populated region is undergoing severe climatic and socioeconomic changes, and it is unclear whether these changes will worsen or mitigate plant invasions. Predictions are often biased, as species may not be in equilibrium in the invaded environment, depending on their invasion stage and ecological characteristics. To address future predictions uncertainty, we identified invasion hotspots across multiple biased modelling scenarios and ecological characteristics of successful invaders. We selected 92 alien plant species widespread in Mediterranean Europe and compiled data on their distribution in the Mediterranean and worldwide. We combined these data with environmental and propagule pressure variables to model global and regional species niches, and map their current and future habitat suitability. We identified invasion hotspots, examined their potential future shifts, and compared the results of different modelling strategies. Finally, we generalised our findings by using linear models to determine the traits and biogeographic features of invaders most likely to benefit from global change. Currently, invasion hotspots are found near ports and coastlines throughout Mediterranean Europe. However, many species occupy only a small portion of the environmental conditions to which they are preadapted, suggesting that their invasion is still an ongoing process. Future conditions will lead to declines in many currently widespread aliens, which will tend to move to higher elevations and latitudes. Our trait models indicate that future climates will generally favour species with conservative ecological strategies that can cope with reduced water availability, such as those with short stature and low specific leaf area. Taken together, our results suggest that in future environments, these conservative aliens will move farther from the introduction areas and upslope, threatening mountain ecosystems that have been spared from invasions so far. [ABSTRACT FROM AUTHOR]

Recreational vessels are an important pathway for spreading marine non‐indigenous species (NIS) around coastal environments globally. However, most vessels are not tracked, limiting our ability to map their movements and identify locations at greater risk of NIS introductions. Using New Zealand as a case study, we quantified spread and risk patterns of recreational vessel movements, using a web‐based survey allowing the more than 1,800 respondents to map significant trips with over 12,000 visits. These vessel routes were used to build a network model representing nationwide recreational vessel movements. Two proxies were used to quantify the risk of introduction of marine NIS: (i) incoming hull length and (ii) cumulative residency periods at sites. There was significant variation in the distances travelled, the destinations they visited and the duration of their stays. New Zealand's recreational boating network contained 317 destinations with over 4,000 unique connections, concentrated within two distinct areas of the country. Network‐based metrics and risk proxies quantified the relative importance of domestic locations as incursion or spreading hubs for NIS. This approach highlighted several areas that pose high relative biosecurity risk within the national network, but are underrepresented within current surveillance programmes. Synthesis and applications. Our study demonstrates how the movement dynamics of recreational vessels can be quantified at a regional scale to inform proactive management. The identification of spreading hubs and locations at particular risk of NIS introductions, enables managers to design risk‐based and effective surveillance and monitoring programmes. Our network‐based approach to determine the biosecurity implications posed by recreational vessels is transferable to other parts of the world. It enables managers to understand the distribution of risk within an area of interest (e.g. a jurisdiction) and develop optimised approaches for mitigating impact. [ABSTRACT FROM AUTHOR]

Reconstructing biological invasions from historical sources can provide insights into how they occur but are difficult to do when invasions are poorly documented. Genetic signatures left by invaders can also offer insights into invasion routes, points of origin and general biology but often present conclusions that are contradictory to expectations. Here, we test the ability of continental‐wide microsatellite genotype data from 29 loci and 3122 samples to reconstruct the well‐documented invasion of red foxes Vulpes vulpes from the United Kingdom into Australia over 150 years ago, an invasion that has led to the extinction of many native species. Our analysis reveals several key signals of invasion evident in Australian foxes. They display lower levels of diversity than foxes sampled from the UK, exhibit clines in diversity from the point of introduction (south‐east Australia) to the edge of their range, and show strong evidence of allele surfing in westerly and north‐easterly directions. These characteristics are consistent with a single point of origin followed by rapid expansion in westerly and north‐easterly directions as suggested by historical records. We also find little genetic structure in foxes across Australia with only the vast Nullarbor Plains and Great Victoria Desert region presenting a detectable barrier to their dispersal. As such, no mainland region within the current range of foxes can be considered genetically isolated and therefore appropriate for localised eradication efforts. Overall, our analyses demonstrate the ability of comprehensive population genetic studies to reconstruct invasion histories even after more than 80 years since colonisation was stabilised. [ABSTRACT FROM AUTHOR]

The pace of biological invasions has increased in recent decades, leading to multiple invasions and the potential dominance of invasive species, destabilizing local ecological networks. This provides opportunities to study new ecological species interactions, including predation. Tropical freshwaters have been particularly concerned by aquatic invasions and we focused here on the Martinique island (Lesser Antilles). We examined the predator–prey relationships involving invasive Thiarid snails (Tarebia granifera and Melanoides tuberculata) and the native Neritina punctulata, both confronted with a newcomer predator, the redclaw crayfish (Cherax quadricarinatus). We conducted several mesocosm experiments to assess the impact of crayfish predation on snail survival and the passive and active antipredator responses of snails. A first experiment indicated snail survival rates between 50% and 80%, depending on crayfish size and sex. Notably, there was a negative correlation between snail survival and male crayfish size and the predation method (shell crushing vs. "body sucking") varied with crayfish size. The second experiment suggested no refuge size for snails, with both very small (<5 mm) and very large (>5 mm) unable to escape predation, regardless of crayfish size (from 77 to 138 mm) or sex. Finally, we investigated the escape behavior of Thiarids regarding three crayfish cues. Melanoides tuberculata tend to bury in the substrate and T. granifera to climb up aquarium walls, what was expected from their shell morphologies, and both responding to crayfish cues within minutes. Overall, C. quadricarinatus proves to be an efficient snail predator with limited escape options for snails, potentially contributing to the decline of certain snail populations in Martinique. This omnivorous predator might impact other native species across different groups, including shrimps and fish. Our study underscores the urgent need for monitoring efforts, solidifying the redclaw crayfish reputation as a dangerous invasive species for freshwater macrobenthic faunas worldwide. [ABSTRACT FROM AUTHOR]

The Environmental Impact Classification for Alien Taxa (EICAT) is an important tool for biological invasion policy and management and has been adopted as an International Union for Conservation of Nature (IUCN) standard to measure the severity of environmental impacts caused by organisms living outside their native ranges. EICAT has already been incorporated into some national and local decision‐making procedures, making it a particularly relevant resource for addressing the impact of non‐native species. Recently, some of the underlying conceptual principles of EICAT, particularly those related to the use of the precautionary approach, have been challenged. Although still relatively new, guidelines for the application and interpretation of EICAT will be periodically revisited by the IUCN community, based on scientific evidence, to improve the process. Some of the criticisms recently raised are based on subjectively selected assumptions that cannot be generalized and may harm global efforts to manage biological invasions. EICAT adopts a precautionary principle by considering a species' impact history elsewhere because some taxa have traits that can make them inherently more harmful. Furthermore, non‐native species are often important drivers of biodiversity loss even in the presence of other pressures. Ignoring the precautionary principle when tackling the impacts of non‐native species has led to devastating consequences for human well‐being, biodiversity, and ecosystems, as well as poor management outcomes, and thus to significant economic costs. EICAT is a relevant tool because it supports prioritization and management of non‐native species and meeting and monitoring progress toward the Kunming–Montreal Global Biodiversity Framework (GBF) Target 6. [ABSTRACT FROM AUTHOR]

The highly invasive weed Parthenium hysterophorus flowers during both hot, humid summers and cold, dry winters in Nepal, yet it remains unknown if there are differences in seed germination and seedling growth during these contrasting seasons. We analysed seed germination and seedling growth of summer and winter cohorts of P. hysterophorus in Kathmandu Valley. Seeds were germinated at low (25/15°C) and high (30/20°C) temperatures, 12/12 h photoperiod and complete dark, and at different levels of water stress. Seedlings were grown in a greenhouse to determine biomass allocation and relative growth rate (RGR). Winter seeds had higher seed biomass than summer seeds, and both seed types germinated under complete dark and 12/12 h photoperiod. Summer seeds germinated at significantly lower rates and percentage than winter seeds at the low temperature, but this difference in germination was not present when summer and winter seeds were incubated at the high temperature. Winter seeds had higher germination (percentage and rate) and took a longer time to reach maximum germination than summer seeds at different levels of water stress. Seedling emergence of both seed types declined with increasing soil depth. Seedling RGRs were nearly equal (summer: 73 mg g−1 day−1, winter: 77 mg g−1 day−1). Biomass allocation to stem and leaves were similar in both cohorts but root biomass allocation was higher in the winter than in the summer cohort. Overall, the maternal environmental effect was moderate on seed germination, and weak on seedling growth. Lack of a pronounced difference in the germination and seedling growth of summer and winter cohorts of P. hysterophorus suggests a wide environmental tolerance of the species, and this could be one of the reasons for the species' ability to invade diverse climatic and geographic regions globally. [ABSTRACT FROM AUTHOR]

Reconstructing biological invasions from historical sources can provide insights into how they occur but are difficult to do when invasions are poorly documented. Genetic signatures left by invaders can also offer insights into invasion routes, points of origin and general biology but often present conclusions that are contradictory to expectations. Here, we test the ability of continental‐wide microsatellite genotype data from 29 loci and 3122 samples to reconstruct the well‐documented invasion of red foxes Vulpes vulpes from the United Kingdom into Australia over 150 years ago, an invasion that has led to the extinction of many native species. Our analysis reveals several key signals of invasion evident in Australian foxes. They display lower levels of diversity than foxes sampled from the UK, exhibit clines in diversity from the point of introduction (south‐east Australia) to the edge of their range, and show strong evidence of allele surfing in westerly and north‐easterly directions. These characteristics are consistent with a single point of origin followed by rapid expansion in westerly and north‐easterly directions as suggested by historical records. We also find little genetic structure in foxes across Australia with only the vast Nullarbor Plains and Great Victoria Desert region presenting a detectable barrier to their dispersal. As such, no mainland region within the current range of foxes can be considered genetically isolated and therefore appropriate for localised eradication efforts. Overall, our analyses demonstrate the ability of comprehensive population genetic studies to reconstruct invasion histories even after more than 80 years since colonisation was stabilised. [ABSTRACT FROM AUTHOR]

The pace of biological invasions has increased in recent decades, leading to multiple invasions and the potential dominance of invasive species, destabilizing local ecological networks. This provides opportunities to study new ecological species interactions, including predation. Tropical freshwaters have been particularly concerned by aquatic invasions and we focused here on the Martinique island (Lesser Antilles). We examined the predator–prey relationships involving invasive Thiarid snails (Tarebia granifera and Melanoides tuberculata) and the native Neritina punctulata, both confronted with a newcomer predator, the redclaw crayfish (Cherax quadricarinatus). We conducted several mesocosm experiments to assess the impact of crayfish predation on snail survival and the passive and active antipredator responses of snails. A first experiment indicated snail survival rates between 50% and 80%, depending on crayfish size and sex. Notably, there was a negative correlation between snail survival and male crayfish size and the predation method (shell crushing vs. "body sucking") varied with crayfish size. The second experiment suggested no refuge size for snails, with both very small (<5 mm) and very large (>5 mm) unable to escape predation, regardless of crayfish size (from 77 to 138 mm) or sex. Finally, we investigated the escape behavior of Thiarids regarding three crayfish cues. Melanoides tuberculata tend to bury in the substrate and T. granifera to climb up aquarium walls, what was expected from their shell morphologies, and both responding to crayfish cues within minutes. Overall, C. quadricarinatus proves to be an efficient snail predator with limited escape options for snails, potentially contributing to the decline of certain snail populations in Martinique. This omnivorous predator might impact other native species across different groups, including shrimps and fish. Our study underscores the urgent need for monitoring efforts, solidifying the redclaw crayfish reputation as a dangerous invasive species for freshwater macrobenthic faunas worldwide. [ABSTRACT FROM AUTHOR]

Freshwater megafish species, such as sturgeons, salmonids, carps, and catfishes, have a maximum reported weight ≥30 kg. Due to their charisma and economic value, they have been widely introduced outside of their native ranges. Here, we provide a comprehensive overview of the introduction of freshwater megafish and an assessment of their environmental impacts. Of the 134 extant freshwater megafish species, 46% have been introduced to new environments, and of these, 69% have established self‐sustaining alien populations. These introductions affect 59% of the world's main basins, with the USA and western Europe being particular hotspots of megafish introductions. The common carp (Cyprinus carpio) is the most widely introduced species. Using the Environmental Impact Classification for Alien Taxa (EICAT and EICAT+) frameworks, we assessed the severity and type of negative and positive impacts posed by alien megafish on native species. Alien megafish caused negative impacts through nine different mechanisms, with predation being the most frequently reported mechanism, followed by herbivory and competition. Moreover, 58% of the alien megafish species with sufficient data to evaluate the severity of their impacts caused declining populations of native species, or worse, extirpations of native species populations. The positive environmental impacts of alien megafish were far less frequently documented. They include biotic interactions that benefit native species, and the provision of trophic resources or habitats. Widely introduced or extensively studied species are more likely to have documented severe impacts on native species. There is a clear trade‐off between the economic benefits associated with megafish introductions and the severe adverse impacts they have on native biodiversity. Our study highlights the need for comprehensive risk assessments to evaluate the potential environmental impacts of megafish. More research and long‐term monitoring schemes are required to inform management actions to protect biodiversity, particularly in the Global South. [ABSTRACT FROM AUTHOR]

Native biodiversity loss and invasions by nonindigenous species (NIS) have massively altered ecosystems worldwide, but trajectories of taxonomic and functional reorganization remain poorly understood due to the scarcity of long‐term data. Where ecological time series are available, their temporal coverage is often shorter than the history of anthropogenic changes, posing the risk of drawing misleading conclusions on systems' current states and future development. Focusing on the Eastern Mediterranean Sea, a region affected by massive biological invasions and the largest climate change‐driven collapse of native marine biodiversity ever documented, we followed the taxonomic and functional evolution of an emerging "novel ecosystem", using a unique dataset on shelled mollusks sampled in 2005–2022 on the Israeli shelf. To quantify the alteration of observed assemblages relative to historical times, we also analyzed decades‐ to centuries‐old ecological baselines reconstructed from radiometrically dated death assemblages, time‐averaged accumulations of shells on the seafloor that constitute natural archives of past community states. Against expectations, we found no major loss of native biodiversity in the past two decades, suggesting that its collapse had occurred even earlier than 2005. Instead, assemblage taxonomic and functional richness increased, reflecting the diversification of NIS whose trait structure was, and has remained, different from the native one. The comparison with the death assemblage, however, revealed that modern assemblages are taxonomically and functionally much impoverished compared to historical communities. This implies that NIS did not compensate for the functional loss of native taxa, and that even the most complete observational dataset available for the region represents a shifted baseline that does not reflect the actual magnitude of anthropogenic changes. While highlighting the great value of observational time series, our results call for the integration of multiple information sources on past ecosystem states to better understand patterns of biodiversity loss in the Anthropocene. [ABSTRACT FROM AUTHOR]

Aim: Spreading infectious diseases associated with introduced pathogens can have devastating effects on native biota and human livelihoods. We analyse the global distribution of 100 major alien fungal and oomycete pathogens with substantial socio‐economic and environmental impacts and examine their taxonomy, ecological characteristics, temporal accumulation trajectories, regional hot‐ and coldspots of taxon richness and taxon flows between continents. Location: Global. Taxon: Alien/cryptogenic fungi and fungus‐like oomycetes, pathogenic to plants or animals. Methods: To identify over/underrepresented classes and phyla, we performed Chi2 tests of independence. To describe spatial patterns, we calculated the region‐wise richness and identified hot‐ and coldspots, defined as residuals after correcting taxon richness for region area and sampling effort via a quasi‐Poisson regression. We examined the relationship with environmental and socio‐economic drivers with a multiple linear regression and evaluated a potential island effect. Regional first records were pooled over 20‐year periods, and for global flows the links between the native range to the alien regions were mapped. Results: Peronosporomycetes (Oomycota) were overrepresented among taxa and regional taxon richness was positively correlated with area and sampling effort. While no island effect was found, likely due to host limitations, hotspots were correlated with human modification of terrestrial land, per capita gross domestic product, temperate and tropical forest biomes, and orobiomes. Regional first records have increased steeply in recent decades. While Europe and Northern America were major recipients, about half of the taxa originate from Asia. Main Conclusions: We highlight the putative importance of anthropogenic drivers, such as land use providing a conducive environment, contact opportunities and susceptible hosts, as well as economic wealth likely increasing colonisation pressure. While most taxa were associated with socio‐economic impacts, possibly partly due to a bias in research focus, about a third show substantial impacts to both socio‐economy and the environment, underscoring the importance of maintaining a wholescale perspective across natural and managed systems. [ABSTRACT FROM AUTHOR]

Understanding why some, but not other, plant communities are vulnerable to alien invasive species is essential for predicting and managing biological invasions. Darwin proposed two seemingly contradictory hypotheses on how native‐invader relatedness influences invasion success, emphasizing, respectively, the importance of environmental filtering and competition between natives and invaders. Despite much recent empirical research on this topic, reconciling these two hypotheses, known as Darwin's naturalization conundrum, remains a challenge.Using plot‐level data from natural forests along elevational transects covering strong environmental gradients, we examined whether the invasion of the globally invasive species crofton weed (Ageratina adenophora) can be explained by environmental filtering and/or competition from closely related species linked to environmental gradients.Abundant precipitation, warm temperatures, open canopies and postfire environments facilitated A. adenophora invasion, whereas resident taxonomic richness suppressed its invasion. Importantly, we found that invader‐resident relatedness had a strong negative effect on invader cover under resource scarcity conditions (e.g. low water availability), but not under non‐resource environmental stress gradients (e.g. low temperature).Synthesis and applications. Our results suggest that the impact of species phylogenetic relatedness on invasion success varies distinctly along resource versus non‐resource environmental gradients. These results help to reconcile Darwin's naturalization conundrum, thereby improving the ability to predict the success of alien plant invasions in a changing world. Our study stresses the need to consider adjusting forest species composition to strengthen their resistance to invasion, while taking into account resource and non‐resource environmental gradients, particularly after wildfires. [ABSTRACT FROM AUTHOR]

International trade has been favouring the dissemination of a wide suite of invasive alien species. Upstream prevention through the monitoring of entry points is identified as an appropriate strategy to achieve control of bioinvasions and their consequences. Maritime transportation has been responsible for the introduction worldwide of exotic rodents that are major pests for crops and food stocks as well as reservoirs of many zoonotic pathogens. In order to limit further dissemination, the International Health Regulation constrains decisions makers and socio‐economic stakeholders to manage ship‐mediated import/export of rodents within seaports.Unfortunately, eco‐evolutionary insights into rodent introduction events that could guide preventive actions in seaports are very scarce. In order to bridge this gap, we here describe the results of a 3 year‐long survey of small mammals conducted in the Port of Cotonou, Benin.Our aim was to assess the spatiotemporal distribution, diversity and relative abundance of invasive and native rodents.960 small mammal individuals were captured in nine within‐seaport sites. We found (i) a marked predominance of invasive species (84% of the individuals belonging to Mus musculus, Rattus rattus, R. norvegicus), (ii) with native species (i.e. Mastomys natalensis and the shrew Crocidura olivieri) essentially restricted to peripheral non‐industrial areas, as well as (iii) a fine‐scale spatial segregation stable over time between the invasive Norway rats and house mice on the one hand, and the black rats and shrews on the other hand.Furthermore, trapping before and after two successive rodent control campaigns indicates that they were ineffective and that subsequent rodent recolonisation occurred 6–12 months following intervention.Synthesis and applications. Our results are discussed in terms of ecological processes at play (e.g. interspecific interactions) and operational recommendations (e.g. assessment of proper eradication units, environmental modifications). [ABSTRACT FROM AUTHOR]

There has been extensive commentary about historical First Nations' land management in Australia, including in tall, wet forests, and therefore their condition at the time of the British invasion in 1788. Popular texts have interpreted records kept by early British invaders to argue that extensive areas of tall, wet forest were kept open through frequent burning by the First Peoples. However, these interpretations conflict with historical and ecological evidence, which is rarely acknowledged in public discourse. Here, we present evidence about what Victorian Mountain Ash (Eucalyptus regnans) forests were like at the time of the British invasion. We show that at the time of the British invasion, most areas of mainland Mountain Ash forests were likely to have been naturally dense and wet, with: (1) overstorey trees spaced relatively widely; and (2) an understorey consisting of a cool temperate rainforest mesic layer. Ecological and physiological evidence suggests that Mountain Ash forests evolved under conditions where high‐severity wildfire was comparatively rare, leading to patterns of landscape‐level cover dominated by relatively mature forests. This is broadly consistent with reports from the First Peoples, early historical accounts, paintings, and photographs. These forests were not open or park‐like, as may have been the case in some other Australian vegetation types. However, these forests were not wilderness, but places of significance to the First Peoples. Understanding forest structure at the time of the British invasion is critically important in establishing historical reference conditions for guiding appropriate restoration programmes, especially the reinstatement of traditional ecological knowledge, after long periods of post‐British invasion disturbance and degradation. Notably, the dense, wet understorey that characterizes Mountain Ash forests should be recognized as an inherent and entirely natural part of the ecological dynamics of this ecosystem, with approaches to thin, burn, or remove it highly likely to be counterproductive and have a range of detrimental environmental effects. [ABSTRACT FROM AUTHOR]

Ailanthus altissima is one of the major invasive trees at a global scale. Despite numerous reports about its invasiveness in different habitats, so far it was not observed on harsh ultramafic soils and to colonize the vegetation of these outcrops. In this paper we show that the species can also spread in these habitats in the Mediterranean region and is able to cope with the severe anomalies of ultramafic soils. We sampled A. altissima in four ultramafic outcrops of central Italy and in control sites to unravel the behavior of this species toward the typically high soil concentrations of trace metals, such as Ni, Cr and Co, as well the imbalance of the Ca:Mg quotient. A similar sampling was performed for the native Fraxinus ornus that occurs naturally on a broad range of soils, including those from ultramafic rocks. Trace metal concentrations in leaves of both species were below toxicity thresholds, but A. altissima showed lower translocation and bioaccumulation factors (TF and BF, respectively) for Ni. Compared with F. ornus, the invasive species displayed higher leaf concentrations of Mg, thus suggesting a higher tolerance of potentially toxic levels of this element. Moreover, the higher TF and BF values for Ca in both control and serpentine populations suggested that A. altissima was more able to extract and accumulate this macronutrient in leaves in respect to F. ornus. Given the inherent deficiency of this element in ultramafic soils, efficient use of Ca could be a key trait contributing to the invasiveness of A. altissima on these soils. [ABSTRACT FROM AUTHOR]

Aim Location Taxa Methods Results Main Conclusions Investigating the extent of insular invasions by non‐native species (i.e., the number of islands they occupy) is central to island conservation. However, interrelationships among plant life history traits, naturalization histories, and island characteristics in determining island occupancy by non‐native plant species are poorly understood. We investigated whether island occupancy by different non‐native plant species declines in relation to their year of first naturalization and whether periods of first naturalization differ among growth forms, dispersal modes, and biogeographic origins. Then, we asked if non‐native plants that naturalized more recently occur more frequently on islands that are large, less isolated, and close to urban areas. We contrasted trends across growth forms, dispersal modes, and biogeographic origins.264 offshore islands in northern Aotearoa New Zealand.Vascular plant species.We combined field surveys and published data for 767 non‐native plant species on the islands. We categorized each species according to its growth form (n = 3), dispersal mode (n = 4) and biogeographic origin (n = 5) and identified its year of first naturalization in Aotearoa New Zealand. We tested our hypotheses using ANCOVA and generalized linear models (GLMs).There were similar declines in island occupancy in relation to the year of first naturalization in Aotearoa New Zealand across all trait and biogeographic origin categories. First naturalization times of herbaceous species, those with unspecialized dispersal modes, and those originating from Eurasia and the Mediterranean basin were disproportionately earlier than other categories. Non‐native plants with more recent first naturalization occur more frequently on large islands close to urban areas, but not on less isolated ones. Relationships with island characteristics did not differ among trait and biogeographic origin categories.Overall, time of first naturalization was more important than trait and biogeographic origin categories in explaining non‐native plant invasion patterns on islands. Since there were similar relationships between island occupancy and the year of first naturalization in Aotearoa New Zealand for all categories, management bodies should focus on non‐native plant species of trait and biogeographic origin categories that have naturalized recently (e.g., woody species from other regions within Oceania), and on large islands close to urban areas. Introduction and naturalization histories provide essential context for interpreting the role of plant traits and biogeographic origin in understanding plant invasions on islands. [ABSTRACT FROM AUTHOR]

Aim: Changes in fire regimes and biological invasions are major threats to tropical savannas. Fire is a key driver of community composition in these ecosystems and can be used as a management tool to control some invasive alien species, while being advantageous to native ones. However, we still do not fully comprehend the interactive effects of these threats on native plant communities. Here, we conducted an experiment in southeastern Brazil to investigate how variation in the composition of native communities invaded either by Melinis minutiflora or Urochloa brizantha is affected by fire in different seasons: early‐dry season, mid‐dry season and late‐dry season in comparison to fire suppression. Location: Itirapina, state of São Paulo, southeastern Brazil (22°14′07″S 47°53′07″W). Results: The effects of fire seasons and invasive species were independent for species richness but interactive for species gains and losses. In general, the identity of the invasive species was a key factor driving community dynamics, with fire seasons playing a weaker role. Invaded communities changed gradually over time and the major changes happened over longer time lags. Communities invaded by M. minutiflora gained more species than those invaded by U. brizantha. Thus, communities invaded by M. minutiflora also had more variation in their species richness through time than those invaded by U. brizantha. Conclusions: Although biological invasions and fire seasons interacted as drivers of change in native savanna communities, the identity of the invasive species played a stronger role. Communities invaded by M. minutiflora gained more species and were more variable than those invaded by U. brizantha. [ABSTRACT FROM AUTHOR]

In the context of risk analysis, horizon scanning activity is a necessary component of any foresight process. This applies also to the specific context of biological invasions, supported and accelerated by climate change and global trade. Today, various institutions and research centres are equipped with a set of tools and methods for early warning on emerging threats. In the case of plant pests, web signals, trade data, community science data and sentinel plants are important sources of information, then analysed and elaborated through multicriteria approaches. The scope of this paper is to provide an overview of current practices, highlighting strengths and shortcomings, and to inform future research and policy initiatives about opportunities to address global change in this field. [ABSTRACT FROM AUTHOR]

Invasive species are significant drivers of global change due to their ecological impact, as well as the economic costs associated with managing them. While habitat selection studies have been an essential tool for managing endangered species, they have not been widely used for invasive species. A prime example of an invasive species is the red‐whiskered bulbul, which has spread to several parts of the world from Asia. This study focused on macrohabitat selection analysis during the winter of 2019–2020, with 200 point counts conducted over 784 km2 to identify habitats that are selected and avoided by the invader species in eastern Spain. In addition, the study analyzed 18 variables related to microhabitat, vegetation, and anthropogenic factors to determine those that are relevant for its abundance in the selected areas (74 point counts over 784 km2). The study found that the red‐whiskered bulbul was not detected in natural Mediterranean vegetation such as forests and shrubs or crops, even though they were the dominant ecosystems, accounting for 52.8% of the study area. Instead, suburban areas were selected, and the species was more abundant near its initial release point and in areas with orchards containing fruit trees and plants. Therefore, the study suggests that natural Mediterranean habitats and crops may act as ecological barriers to the expansion of this species, while suburban areas would increase their ability to expand. The study's findings should be considered in managing the red‐whiskered bulbul in Mediterranean areas. [ABSTRACT FROM AUTHOR]

Rapid evolution in colonising populations can alter our ability to predict future range expansions. Recent theory suggests that the dynamics of replicate range expansions are less variable, and hence more predictable, with increased selection at the expanding range front. Here, we test whether selection from environmental gradients across space produces more consistent range expansion speeds, using the experimental evolution of replicate duckweed populations colonising landscapes with and without a temperature gradient. We found that the range expansion across a temperature gradient was slower on average, with range‐front populations displaying higher population densities, and genetic signatures and trait changes consistent with directional selection. Despite this, we found that with a spatial gradient range expansion speed became more variable and less consistent among replicates over time. Our results therefore challenge current theory, highlighting that chance can still shape the genetic response to selection to influence our ability to predict range expansion speeds. [ABSTRACT FROM AUTHOR]

In recent decades, ecological niche models (ENMs) have been widely used to predict suitable habitats for species. However, for invasive organisms, the prediction accuracy is unclear. In this study, we employed the most widely used maximum entropy (MaxEnt) model and ensemble model (EM) Biomod2 and verified the practical effectiveness of the ENM in predicting the distribution areas of invasive insects based on the true occurrence of Hyphantria cunea in China. The results showed that when only limited data of invasive areas were used, the two ENMs could not effectively predict the distribution of suitable habitats of H. cunea, although the use of global data can greatly improve the prediction accuracy of ENMs. When analyzing the same data, Biomod2's prediction accuracy was significantly better than that of MaxEnt. For long‐term predictions, the area of suitable habitat predicted by the ENMs was much greater than the occurrence area; for short‐term predictions, the accuracy of the predicted area was significantly improved. Under the current conditions, the area of suitable habitat for H. cunea in China is 118 × 104 km2, of which 59.32% is moderately or highly suitable habitat. Future climate change could significantly increase the suitable habitat area of H. cunea in China, and the predicted area of suitable habitats in all climate scenarios exceeded 355 × 104 km2, accounting for 36.98% of the total land area in China. This study demonstrates the use of ENMs to study invasive insects and provides a reference for the management of H. cunea in China. [ABSTRACT FROM AUTHOR]

The rate of biological invasions is steadily increasing, with major ecological and economic impacts accounting for billions of dollars in damage as a result. One spectacular example is the western Atlantic invasion by lionfishes. In the Mediterranean Sea, invasions from the Red Sea via the Suez Canal (termed Lessepsian invasions) comprise more than 100 fish species, including a recent invasion by lionfish. In light of the devastating effects of lionfish in the Caribbean Sea, understanding the dynamics of Mediterranean lionfish invasion is crucial. The Lessepsian lionfish invasion started in 2012, and rapidly spread to the central Mediterranean. Here, we used thousands of RAD seq genomic markers to study the population dynamics of this invasion. While we did not find a reduction in genetic diversity between source (Red Sea) and invasive (Mediterranean) populations (i.e., bottleneck effects), we found evidence of population structure within the invasive range in the Mediterranean Sea. We found that loci that are potentially under selection may play an important role in invasion success (in particular, genes involved in osmoregulation and fin spine sizes). Genomic approaches proved powerful in examining the ecological and evolutionary patterns of successful invaders and may be used as tools to understand and potentially mitigate future invasions. [ABSTRACT FROM AUTHOR]

The increasing spread of marine non‐indigenous species (NIS) due to the growth in global shipping traffic is causing widespread concern for the ecological and economic impacts of marine bioinvasions. Risk management authorities need tools to identify pathways and source regions of priority concern to better target efforts for preventing NIS introduction. The probability of a successful NIS introduction is affected by the likelihood that a marine species entrained in a transport vector will survive the voyage between origin and destination locations and establish an independently reproducing population at the destination. Three important risk factors are voyage duration, range of environmental conditions encountered during transit and environmental similarity between origin and destination. In this study, we aimed for a globally comprehensive approach to assembling quantifications of source‐destination risk factors from every potential origin to every potential destination. To derive estimates of voyage‐related marine biosecurity risk, we used computer‐simulated vessel paths between pairs of ecoprovinces in the Marine Ecoregions Of the World biogeographic classification system. We used the physical length of each path to calculate voyage duration risk and the cross‐latitudinal extent of the path to calculate voyage path risk. Environmental similarity risk was based on comparing annual average sea surface temperature and salinity within each ecoprovince to those of other ecoprovinces. We derived three separate sets of risk quantifications, one each for voyage duration, voyage path and environmental similarity. Our quantifications can be applied to studies that require source‐destination risk estimates. They can be used separately or combined, depending on the importance of the types of source‐destination risks that might be relevant to particular scientific or risk management questions or applications. [ABSTRACT FROM AUTHOR]

Palearctic water frogs (genus Pelophylax) are an outstanding model in ecology and evolution, being widespread, speciose, either threatened or threatening to other species through biological invasions, and capable of siring hybrid offspring that escape the rules of sexual reproduction. Despite half a century of genetic research and hundreds of publications, the diversity, systematics and biogeography of Pelophylax still remain highly confusing, in no small part due to a lack of correspondence between studies. To provide a comprehensive overview, we gathered >13,000 sequences of barcoding genes from >1700 native and introduced localities and built multigene mitochondrial (~17 kb) and nuclear (~10 kb) phylogenies. We mapped all currently recognized taxa and their phylogeographic lineages (>40) to get a grasp on taxonomic issues, cyto‐nuclear discordances, the genetic makeup of hybridogenetic hybrids, and the origins of introduced populations. Competing hypotheses for the molecular calibration were evaluated through plausibility tests, implementing a new approach relying on predictions from the anuran speciation continuum. Based on our timetree, we propose a new biogeographic paradigm for the Palearctic since the Paleogene, notably by attributing a prominent role to the dynamics of the Paratethys, a vast paleo‐sea that extended over most of Europe. Furthermore, our results show that distinct marsh frog lineages from Eastern Europe, the Balkans, the Near East, and Central Asia (P. ridibundus ssp.) are naturally capable of inducing hybridogenesis with pool frogs (P. lessonae). We identified 14 alien lineages (mostly of P. ridibundus) over ~20 areas of invasions, especially in Western Europe, with genetic signatures disproportionally pointing to the Balkans and Anatolia as the regions of origins, in line with exporting records of the frog leg industry and the stocks of pet sellers. Pelophylax thus emerges as one of the most invasive amphibians worldwide, and deserves much higher conservation concern than currently given by the authorities fighting biological invasions. [ABSTRACT FROM AUTHOR]

Human trade and movements are central to biological invasions worldwide. Human activities not only transport species across biogeographical barriers, but also accelerate their post‐introduction spread in the landscape. Thus, by constraining human movements, the spatial structure of road networks might greatly affect the regional spread of invasive species. However, few invasion models have accounted for the topology of road networks so far, and its importance for explaining the regional distribution of invasive species remains mostly unexplored. To address this issue, we developed a spatially explicit and mechanistic human‐mediated dispersal model that accounts and tests for the influence of transport networks on the regional spread of invasive species. Using as a model the spread of the invasive ant Lasius neglectus in the middle Rhône valley (France), we show that accounting for the topology of road networks improves our ability to explain the current distribution of the invasive ant. In contrast, we found that using human population density as a proxy for the frequency of transport events decreases models' performance and might thus not be as appropriate as previously thought. Finally, by differentiating road networks into sub‐networks, we show that national and regional roads are more important than smaller roads for explaining spread patterns. Overall, our results demonstrate that the topology of transport networks can strongly bias regional invasion patterns and highlight the importance of better incorporating it into future invasion models. The mechanistic modelling approach developed in this study should help invasion scientists explore how human‐mediated dispersal and topography shape invasion dynamics in landscapes. Ultimately, our approach could be combined with demographic, natural dispersal and environmental suitability models to refine spread scenarios and improve invasive species monitoring and management at regional to national scales. Keywords: biological invasions, human‐mediated dispersal, road network, secondary spread, spatially explicit model, stochastic jump model [ABSTRACT FROM AUTHOR]