A growing number of emerging non-native species are expanding within their introduced ranges and may become increasingly problematic in the future. Among them, several Solanum taxa pose underappreciated ecological and economic risks. Solanum nitidibaccatum , a poorly studied annual native to South America and increasingly recorded across Europe, represents a suitable model for understanding the establishment of non-native ruderal and segetal Solanum species in a transformed landscape. We examined how the composition and functional structure of ruderal vegetation influence the occurrence of S. nitidibaccatum , hypothesizing that habitat filtering and high functional heterogeneity facilitate its establishment, whereas interspecific competition constrains it. Using community diversity metrics and functional structure indices, we related vegetation properties to the probability of this species occurrence. The probability of S. nitidibaccatum occurrence was higher in species-rich communities and in vegetation characterized by higher leaf dry matter content and greater functional dispersion. In contrast, it declined in assemblages with a stronger contribution of nitrogen-demanding species and taller vegetation with higher specific leaf area. Our findings indicate that the establishment of S. nitidibaccatum is shaped by the interplay between habitat filtering and functional heterogeneity in ruderal vegetation, which may create underutilized niche space that facilitates the spread of this emerging non-native species. Considering its potential capacity to colonize ecologically similar vegetation across a range of transformed ecosystems, S. nitidibaccatum should be regarded as a species with high potential to become a problematic invasive weed. Its continued spread, together with the emergence of other non-native Solanum species, underscores the need for further research to better anticipate ecological and economic consequences that are challenging to predict.

While the influential role of scientific associations in shaping research fields is well recognized, their impact within the domain of invasion science remains underexplored. This review combines qualitative narrative with quantitative metrics to trace the development of Neobiota, the first European non-profit and non-governmental scientific association dedicated to the study of biological invasions. Since its foundation in 1999, the Neobiota network has aimed to foster scientific exchange and collaboration, advance and integrate research across all dimensions of invasion science, and disseminate findings to support evidence-based policies. Evolving rapidly from a German working group into Europe’s leading network for invasion science, Neobiota has united researchers and practitioners across disciplines, taxa, and national boundaries. In contrast to many other associations, Neobiota operates with a low-threshold, non-bureaucratic governance model, promoting inclusivity and cross-border engagement. We document how its biennial conferences—hosted in 12 European countries between 2000 and 2024—have supported thematic diversity (ranging from molecular biology to socio-economy), increasing international participation (9–47 countries globally), and active policy outreach. Thematically, the focus of research presented at conferences has shifted over time from ecological patterns and species inventories to environmental impacts, predictive modeling, management strategies, and socio-political dimensions of invasions. Trends in equity reveal progress toward gender parity among keynote speakers and session chairs. Neobiota has also supported the dissemination of knowledge through two publication platforms: the Neobiota series (2000–2008) and the open-access, peer-reviewed journal NeoBiota launched in 2011. This journal currently operates under an Editorial Board with 75 subject editors and a team of five Co-Editors-in-Chief. We conclude that over the past 25 years, Neobiota has been instrumental in building a cohesive and inclusive scientific community globally, advancing and disseminating interdisciplinary research on biological invasions, and informing policy, particularly in support of legal frameworks to prevent and mitigate the negative impacts of non-native species.

Invasive alien species are one of the most severe threats to island biodiversity. An essential first step in addressing this issue is producing comprehensive inventories of alien species inhabiting them. However, cataloguing alien floras on remote islands is particularly challenging. Botanical surveys are often conducted only after substantial human-driven impacts on local ecosystems, including the introduction of invasive species, have already occurred. This raises the key question of how species’ native origin should be determined on islands with such a recent history of botanical documentation. Site-based methodologies offer a practical, replicable and context-sensitive approach to addressing these challenging knowledge gaps. Here, we present a comprehensive catalogue of the alien spermatophyte flora of Isla del Coco, an eastern Pacific island located approximately 500 km off the Central American mainland and facing the aforementioned challenges. Among the main contributions of this study, we apply an expert-based binary decision tree to classify the wild flora as native, wild alien, or cryptogenic, along with a separate inventory of cultivated species. Our classification system allowed us to identify 89 wild alien species (45.2% of the island’s total wild flora), 78 native species (39.6%), and 30 cryptogenic (15.2%). The naturalised-to-native ratio (0.5) suggests that the island remains highly susceptible to biological invasions. The profile of the alien flora closely resembles that of mainland Central America, with a predominance of unintentionally introduced species, underscoring the need for strict biosecurity measures at landing points. The methodology employed also indicates that site-based approaches may apply stricter criteria for defining native species than previous studies, thereby highlighting new research needs for Isla del Coco, such as clarifying the status of cryptogenic species and investigating the largely unexplored impacts of invasive alien plants.

Estimating the extent and speed of invasive species’ spread is crucial for optimising surveys and management, but this estimation is challenging due to the scale-dependent nature of spread. For instance, when discretising occurrence data to grids to estimate the extent of invaded ranges, larger cells can decrease boundary precision, while smaller cells can increase the risk of missing invaded areas. Moreover, on shorter timescales, such as year-to-year comparisons, spread rates can exhibit lags, accelerations and slowdowns. We present a multiscale spread optimisation methodology developed for the spotted lanternfly ( Lycorma delicatula ), a pest impacting grapes that is spreading in the USA. We analysed a dataset of > 900,000 occurrence records detailing spread from this pest’s initial detection in eastern Pennsylvania in 2014 to its invasion front in Chicago, IL, in 2023. First, we delineated invaded area using square grids with varying cell sizes and α-convex hulls with different boundary resolutions. For each method and scale, we regressed invaded range area against year using both simple linear and logistic non-linear models. Coarser spatial scales yielded faster estimated spread rates, and logistic models outperformed linear regressions, indicating a lag, acceleration and slowdown in annual spread rate. Next, to determine the spatial scale that best captured the invasion front boundary, we used cross-validation, optimising the F β metric, which balances recall and precision. Emphasising recall generally favoured coarser spatial scales and α-convex hulls outperformed grid-based methods. Finally, L. delicatula has dispersed long distances from its primary epicentre, establishing satellite populations. We delineated each satellite population each year since its inception using optimised α-hull values and measured their year-to-year boundary expansion. Like the primary epicentre, these satellite populations showed accelerating expansion, at least until merging with the primary invasion. Overall, the expansion rate of the primary invasion has slowed since 2017, decreasing from a maximum of 21 km/year, possibly due in part to control efforts, although the exact cause remains unresolved. Considering spatial scale and temporal variation can improve the analysis of invasive spread and motivate early interventions to manage nascent epicentres before their spread accelerates.

Soil nutrient heterogeneity can influence the performance of both native and alien plants. However, such effects may be modified by native generalist herbivores and this modification may differ between native and alien plants due to differences in co-evolutionary histories with the herbivores. In a greenhouse experiment, we grew two native and two alien plants either alone or in native-alien pairs in homogeneous or heterogeneous soils, with or without the native generalist herbivore Spodoptera litura . Total biomass of the native plant Alternanthera sessilis and the alien plant Celosia argentea was lower in the heterogeneous than in the homogeneous soils, indicating an overall negative effect of soil nutrient heterogeneity. Although the heterogeneity × herbivory interaction was not significant, post-hoc comparisons revealed species-specific patterns. For A. sessilis , the lowest total biomass occurred in heterogeneous soils under herbivory, whereas the other treatment combinations did not differ significantly. In contrast, for C. argentea , total biomass differences between homogeneous and heterogeneous soils were evident only in the absence of herbivores. Belowground biomass analyses suggest that the contrasting responses were likely to result from species-specific, herbivore-induced trade-offs between the benefits and costs of root foraging precision in heterogeneous soils. These effects, however, were not observed for the native plant Achyranthes bidentata or the alien plant Amaranthus retroflexus . Competition with alien plants reduced aboveground biomass of both native plants, whereas the alien plants were unaffected by competition with natives. Competition did not alter the effects of soil heterogeneity or herbivory. These results indicate that soil nutrient heterogeneity and native generalist herbivores may jointly shape the performance of native and alien plants in a species-specific manner, regardless of competition between them.

The genus Agrilus includes two species, Agrilus planipennis and A. anxius , that are of particular phytosanitary concern and that are regulated by the European Union legislation. This implies that phytosanitary agencies of all EU countries are obliged to establish specific surveillance programmes to verify the absence of these species from their territory. These activities commonly consist of the use of green-coloured traps, which are, however, attractive not only for A. planipennis and A. anxius , but also for a wide range of other Agrilus species. For this reason, much time and expertise is required to sort and identify specimens to species, impeding an efficient rapid response. In this study, we tested the efficacy of the Entomoscope, a low-cost, open-source photomicroscope that uses high-resolution digital imaging and allows a pre-trained Convolutional Neural Networks (CNN) model to accurately detect, image and classify insect specimens, for automatic identification of 13 Agrilus species, including A. planipennis and A. anxius . We benchmarked models from three different CNN architectures and selected YOLOv8l as the most robust performer; this model achieved a Top-1 accuracy of 90.2% on a “real-world” test set (i.e. a dataset simulating real surveillance conditions). For most species, including A. planipennis and A. anxius , either no errors or only a few errors were made, whereas for a few native species, misidentifications were more common. These results provided proof of concept for an AI-driven surveillance system that can strongly aid in surveillance activities of Agrilus species.

Silver carp ( Hypophthalmichthys molitrix ) is a filter-feeding cyprinid introduced globally for aquaculture that poses significant ecological risks to river systems worldwide. In Thailand, its distribution in the Chao Phraya River Basin has remained poorly documented due to limitations of traditional monitoring. This study applied environmental DNA (eDNA) analysis at 39 sites across the Ping, Wang, Yom, Nan, and Chao Phraya rivers during 2019, 2021, and 2023. Detection rates increased from 31% in 2019 to 59% in 2023, with eDNA detected at all sites by the final survey year. Bayesian occupancy modelling revealed moderate occurrence probabilities (ψ = 0.40–0.51) and consistently high laboratory detection reliability (p 11 ≈ 0.90). Temperature was the strongest predictor of detection efficiency, whereas other water-quality parameters had minimal effects on ψ, suggesting that environmental factors mainly influenced detectability rather than species presence. Comparison with Department of Fisheries records showed a contrast between long-term declines in Chinese carp catch and increasing eDNA detections of H. molitrix , indicating continued establishment and expansion of this species. Because official data still combine H. molitrix and bighead carp ( Hypophthalmichthys nobilis ) under one category, eDNA provides the species-level resolution needed to track individual taxa. These results demonstrate that molecular surveillance complements traditional fisheries assessments by offering finer spatial and temporal resolution for detecting introduced species, supporting the integration of eDNA techniques into regional biosecurity programmes.

North American goldenrods ( Solidago spp.) rank among the most ecologically impactful invasive plants in Europe, Asia, and other regions. Their spread is driven by high ecological plasticity, rapid growth, and allelopathic effects. While the number of publications on Solidago invasions has grown substantially in recent decades, existing reviews tend to be narrative and focus on single species or few mechanisms. In this systematic review, we analyze 180 peer-reviewed empirical studies to assess global trends, methodological approaches, and research biases in studies addressing interactions between invasive Solidago and the environment. Most studies applied a single methodological approach, with ex situ experiments dominating, while field observations and in situ manipulative experiments were less common. Long-term studies were rare, and research primarily addressed current conditions rather than future scenarios. The taxonomic focus was centered on S. canadensis L., with other species being much less studied. Geographically, research was concentrated in Europe and Asia, with field-based studies more common in Europe and ex situ experiments dominating in Asia. Solidago spp. served as either a response or an explanatory variable, reflecting both its response to environmental conditions and its impact on the invaded ecosystem.

Management of alien species is a critical conservation priority in protected areas. Reliable alien species checklists are central to prioritisation, early detection, long-term monitoring and reporting. Yet, methods vary widely, from structured field surveys with herbarium vouchers to data aggregated from online platforms, atlases, citizen science and scientific journal publications. These sources often use inconsistent naming systems, especially where alien species names differ between the introduced and native range. We describe the processes used over three decades by South African National Parks to compile alien species lists, highlight key shortcomings and propose a ten-step process to improve checklist development. Our approach generates a dynamic occurrence database that integrates static historical datasets with dynamic sources, such as iNaturalist, from which up-to-date checklists can be produced. Central to this process is taxonomic standardisation against a taxonomic backbone, combined with annotations of identification certainty and spatial accuracy and the assignment of unique record and taxon identifiers. Applying this process across parks yielded a consolidated list of 1,330 unique taxa – significantly longer than previous versions. The increase reflects broader scope (e.g. inclusion of 206 extralimital taxa) and incorporation of new data streams, while some park lists shortened due to removal of misidentified or synonymous taxa. Around one-third of alien species recorded were absent from the national checklist, underscoring the need for a systematic approach to alien species listing. As conservation indicators increasingly depend on such lists, we recommend explicit guidance is provided on: (1) classifying invasion status and stage, especially for cultivated species; (2) treatment of extralimital aliens; and (3) verification standards for non-expert or spatially imprecise records. Using our proposed process alongside such guidelines will provide a robust foundation for consistent alien plant species reporting in protected areas, strengthening the value and application of alien species lists.

The success and impact of invasive non-native species depend on how they cope with local abiotic conditions, especially in comparison to co-occurring native taxa. In aquatic systems, salinity serves as a key environmental filter, mediating the establishment of invasive species and influencing biotic interactions. However, the mechanistic basis behind these context-dependent responses remains poorly understood. In this study, we examined interspecific differences in metabolic rate, movement behaviour, and their relationship between the worldwide invasive Gambusia holbrooki and a threatened Spanish endemic fish Aphanius iberus across an experimentally-manipulated salinity gradient. Using intermittent-flow respirometry and automated tracking of movement patterns, we compared aerobic metabolic traits and movement behaviours under various salinities. Toothcarp maintained a stable aerobic scope across salinity treatments, whereas invasive mosquitofish exhibited a markedly lower aerobic scope with higher salinity, primarily due to a decline in maximum metabolic rate. This stress response was not linked to increased osmoregulatory costs, as baseline metabolism decreased. Behavioural tests demonstrated consistent species differences in routine locomotion, with mosquitofish showing more exploratory behaviour and toothcarp showing more stop-go behaviour and remaining more stationary overall. Notably, in toothcarps, we found a negative link between standard metabolic rate and space use, suggesting that individuals with higher baseline metabolism may be constrained in their movement. Conversely, in mosquitofish, although salinity affected metabolic capacities, this effect was not reflected in their movement, indicating a weak relationship between metabolism and behaviour, likely supported by trait flexibility. By integrating metabolic traits with behavioural data, our results reveal mechanisms underlying invasive species responses and strengthen predictions of their performance relative to native fishes under changing conditions, such as salinity in inland waters. This highlights the importance of trait-based approaches for predicting responses to abiotic stressors and for evaluating the ecological impacts of invasive taxa.