Colocasia esculenta (taro), native to tropical Southeast Asia, is an emergent aquatic plant with a wide global distribution. Valued for its agricultural, horticultural, medicinal, and cultural uses, it also has become invasive in some places, spreading unaided along slow-flowing water courses through corm division. Colocasia esculenta was introduced to South Africa at least a century ago (>> 1918), but widespread invasions are recent, raising concerns that the species could become a harmful invader in the country. This study reviews the history of introduction, invasions, and impacts of C. esculenta around the world; maps its current and potential distribution in South Africa; and, based on a risk analysis, develops recommendations for its management and regulation. Colocasia esculenta has been introduced to at least 180 territories (countries or island states), with records of invasion from 21 of these (9 island and 12 mainland territories). The negative environmental impacts were scored as 'Moderate' with the formation of dense mats leading to declines in local native populations; and socioeconomic impacts scored as 'Minor' as it has irritant properties if not properly handled and prepared. In South Africa, C. esculenta is found in six provinces but most extensively in the Western Cape and KwaZulu-Natal. Based on a species distribution model, C. esculenta could substantially expand its range in areas where it is already established. Colocasia esculenta was classified as 'high risk' for South Africa, with high socio-economic benefits, and as such is identified as a potential conflict generating species. We recommend it is regulated as category 2 (permits are required to carry out any restricted activity) under the South African regulations and suggest exemptions on subsistence farming but prohibitions on all farming in riparian zones. Further investigation is needed for potential management options, including biological control. Recommendations should be reviewed after determining whether some of the subspecific entities present in the country pose a low risk, as then further exemptions or prohibitions might be appropriate. (c) 2024 The Author(s). Published by Elsevier B.V. on behalf of SAAB. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

Up-to-date information on the distribution of alien species is essential for evidence-based management. However, routine monitoring is resource intensive. This has led to regional biases in the availability of information on invasions, with little understanding of invasions in many developing regions, including Africa. This knowledge gap, particularly problematic for marine protected areas (MPAs), challenges the ability of African states to meet their obligations under the Global Biodiversity Framework (GBF) Target 6. This study drew on freely available global databases (Protected Planet; World Register of Introduced Marine Species; World Register of Marine Species) and citizen science data (iNaturalist) to provide novel insights into marine alien species in African MPAs. A total of 27 species were recorded within 17 MPAs across seven countries. The potential threat posed to these MPAs was assessed using the EICAT and SEICAT impact schemes. Worryingly, species known to have impacts of massive or major magnitude were documented in nine MPAs (Table Mountain National Park, Robben Island, Sixteen Mile Beach, Langebaan Lagoon, Namaqua National Park – all in South Africa); Namibian Islands (Namibia); Ilhas Formosa, Nago and Tchedia (Urok) (Guinea-Bissau); Banc d’Arguin National Park (Mauritania); Massa (Morocco)). When used in conjunction with curated databases, iNaturalist offered cost-effective and verifiable records of some alien species in under-surveyed MPAs. By leveraging data from disparate databases, this study improves our knowledge of the scale of invasions in African MPAs and provides a foundation upon which States can prioritise monitoring within their MPA networks. Ultimately, these data could support the development of targeted routine monitoring programmes which could assist the management of marine invasions and the attainment of GBF Target 6.

Biological invasions are one of the major drivers of biodiversity decline and have been shown to have far-reaching consequences for society and the economy. Preventing the introduction and spread of alien species represents the most effective solution to reducing their impacts on nature and human well-being. However, implementing effective solutions requires a good understanding of where the species are established and how biological invasions develop over time. Knowledge of the status and trends of biological invasions is thus key for guiding research efforts, informing stakeholders and policymakers, for targeted management efforts, and preparing for the future. However, information about the status and trends of alien species is scattered, patchy, and highly incomplete, making it difficult to assess. Published reports for individual regions and taxonomic groups are available, but large-scale overviews are scarce. A global assessment therefore requires a review of available knowledge with careful consideration of sampling and reporting biases. This paper provides a comprehensive global assessment of the status and trends of alien species for major taxonomic groups [Bacteria, Protozoa, Stramenopila, Alveolata, and Rhizaria (SAR), fungi, plants, and animals] for Intergovernmental Panel of Biodiversity and Ecosystem Services (IPBES) regions. The review provides irrefutable evidence that alien species have been introduced to all regions worldwide including Antarctica and have spread to even the most remote islands. The numbers of alien species are increasing within all taxa and across all regions, and are often even accelerating. Large knowledge gaps exist, particularly for taxonomic groups other than vascular plants and vertebrates, for regions in Africa and Central Asia, and for aquatic realms. In fact, for inconspicuous species, such as Bacteria, Protozoa, and to some degree SAR and fungi, we found records for very few species and regions. Observed status and trends are thus highly influenced by research effort. More generally, it is likely that all lists for alien species of any taxonomic group and region are incomplete. The reported species numbers therefore represent minima, and we can expect additions to all lists in the near future. We identified six key challenges which need to be addressed to reduce knowledge gaps and to improve our ability to assess trends and status of biological invasions.

This paper provides a brief selective history of research into the ecology and management of alien plant invasions in South Africa. Over 2000 alien plant species have been introduced to the country, and over 750 species are known to have become naturalized or invasive. A striking feature of this naturalized flora is the unusually high dominance of trees and shrubs, making South Africa the world capital of tree invasions. Research into the ecology and management of these invasions began over 100 years ago. In the first half of the 20th century the focus was almost exclusively on biological control and invasive species in the fynbos biome. A broadening research agenda in the second half of the 20th century was facilitated by several initiatives, including the Scientific Committee on Problems of the Environment's (SCOPE) global project on "The Ecology of Biological Invasions" (which had its origins in South Africa), the CSIR's National Programs for Ecosystem Research, and the Working for Water program. In 2004, the world's first (and until recently only) research institute devoted solely to all facets of biological invasions was established in South Africa. This institute (the DST-NRF Centre of Excellence for Invasion Biology) made a substantial contribution to improving the understanding of alien plant invasions, and to building capacity to manage them. The true extent of invasions has proven difficult to estimate, but indications are that 10% of the surface area of the country has been invaded, and that this is increasing. The most invaded biome is the Indian Ocean coastal belt (11 % invaded) followed by the fynbos biome (5 % invaded). Ecological impacts on biodiversity, water resources, livestock production and the severity of wildfires have been reported. Taken together, these impacts are estimated to be costing the country around USD 875 million (approximately ZAR 17 billion) per year, but data on costs are scant. Extensive control programs aimed at eliminating invasive trees and shrubs from the water catchment areas of the fynbos were initiated in the early 1970s. These efforts were expanded in the 1990s by the Working for Water program which operated at a national level with the dual goals of controlling invasive alien plants and creating employment. There have been few robust attempts to monitor the effectiveness of these interventions. Some studies have found that the extent of invasion has been reduced in selected areas while in others control has been ineffective. When assessed at a national scale, it appears that invasions have continued to grow despite control efforts. Populations have declined at a national level for some species under biological control, illustrating the important role that this practice has played. South African scientists have made substantial contributions to the field of invasion science, punching above their weight compared to better-funded developed nations. Challenges to the management of alien plant invasions in future include declining funding and a realisation of the complex social-ecological nature of the problem. Given the capacity and understanding that has been built, South Africa is comparatively well placed to address these challenges. (c) 2025 SAAB. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

The ability to reproduce via multiple strategies is crucial for the invasion success of alien plant species. Here, we use Carpobrotus taxa (species and hybrids) to explore how trade-offs between and within these strategies may influence plant invasion dynamics. Native to South Africa, Carpobrotus plants are globally prominent in coastal ecosystems, reproducing by seed and clonally, and frequently hybridizing in both native and introduced regions. Three genetically distinct clusters were previously identified, with evidence of hybridization within and between these clusters in native and non-native ranges. We collected fruit samples from populations representing the genetic clusters and their hybrids across native and non-native ranges (i.e., Europe, California, and New Zealand). These genetic clusters reflect the complex taxonomy of Carpobrotus, where species boundaries are unclear due to hybridization and morphological similarity. We then assessed seed set, seed mass, germination rates, and early growth under varying abiotic conditions alongside genetic estimates of clonality. Germination rates were influenced by temperature, moisture, and nutrient levels. Non-native populations demonstrated higher seed set, seed mass, and germination success compared to native populations, indicating a stronger investment in sexual reproduction. These populations also showed higher levels of clonality, shown by lower genotypic richness, suggesting that both reproductive strategies enhance invasive potential. High-clonality populations produced more seeds, demonstrating that the two reproductive strategies are not mutually exclusive. These results highlight the importance of multiple reproductive strategies for the establishment and spread of Carpobrotus taxa and provide insights into the mechanisms driving their global success. ### Competing Interest Statement The authors have declared no competing interest.

The occurrence and continuing spread of wilding pines (genus Pinus) in the Cape Floristic Region (CFR), South Africa, impacts negatively on water resources, threatens the region's rich biodiversity, and increases the damage caused by uncontrolled wildfires. The invasive potential and threat of wilding pines has been regularly reported since the 1940s, leading to the development and implementation of various control strategies. The last substantial review of pine invasions and their management in the CFR (in 2012) recommended several actions, including securing more sustainable funding and adopting alternative control methods. We review the last 12 years of wilding pine research and management in the CFR, and provide updates on spread and impact, government funding, payments for ecosystems services initiatives, and contributions of the South African Forest industry. We note an increase in private funding, specifically to address invasion in priority catchment areas in the Greater Cape Town region, as well as a recent decline in government funding. Steps have also been taken to revive research aimed at biological control of pines originating from the Iberian Peninsula. The forest industry has deployed species with lower fecundity in some parts of the CFR and has also started experimenting with hybrids that could potentially be less invasive. New methods for applying herbicides may prove to be more efficient than currently used methods. We discuss five opportunities for addressing current shortcomings in the management of wilding pines, namely broadening sources of funding to increase sustainability, effectively integrating all available management techniques, accommodating the need for commercial forestry, focussing scarce funds on priority areas, and raising awareness. We stress that failure to contain rampant invasions by wilding pines will have far-reaching consequences for conservation in the CFR. (c) 2024 SAAB. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Vachellia farnesiana, a highly invasive species, poses significant ecological challenges due to its widespread establishment in various ecosystems. Understanding the impacts of its invasion on plant communities and soil properties is crucial for effective management and conservation efforts to preserve biodiversity and maintain ecological balance. This study investigates the ecological ramifications of V. farnesiana invasion on the understory of managed forest plant communities. To meet the fuel needs of the railroad networks in what was then British India, now Pakistan, British foresters began planting non-native trees in the Changa Manga Forest in 1866. This managed forest, now recognized as a wildlife sanctuary, is home to a wide variety of flora and is an important habitat for endangered animal species. V. farnesiana was planted in the forest in 1957 for fuel wood production. We systematically surveyed thirty sites using phytosociological methods to assess the impact of V. farnesiana on understory communities. We recorded 47 plant species belonging to 22 plant families and 41 genera. Forty-two percent of the identified species were non-native, whilst 58

The Kunming-Montreal Global Biodiversity Framework (GBF) sets out ambitious global targets to reduce biodiversity loss by 2030 and will determine the conservation agenda for the next decade. Invasive alien species are a major driver of biodiversity loss in terrestrial and marine ecosystems; and a key focus of the GBF is therefore to reduce their introduction by 50% through pathway management as well as eradicating or controlling established alien species in priority sites (Target 6). Protected areas are among the most important priority sites for the management of biological invasions. However, delivery of Target 6 for protected areas entails coordination with other GBF targets especially in relation to rapidly evolving pathways such as increasing international and domestic tourism (Target 15), progressive encroachment of urban areas (Target 12), development of intensive agriculture/aquaculture systems in buffer zones (Target 10), species rafting on marine plastic (Target 7), and growing risk from range-shifting species under climate change (Target 8). The management of established invasive alien species requires effective spatial planning (Target 1) to prioritise the limited human and financial resources available to manage biological invasions including recognising those protected areas facing the greatest immediate and future threat, identifying the species that pose the greatest risk to threatened species (Target 4) and/or Nature’s Contributions to People (Target 11), and obtaining the necessary finance required to effectively control priority species (Target 19). The goal of expanding protected areas to cover 30% of land, water, and seas (Target 3) will need to avoid the inclusion of areas already harbouring invasive alien species. Addressing biological invasions must be an inclusive process (Target 22) undertaken over multiple years that involves the sharing of knowledge and data (Target 21). Decision-makers, protected area managers, researchers, and representative of local communities should all be involved in the regular prioritisation, implementation, and review of management activities. Consequently, the effective management of biological invasions to halt biodiversity loss by 2030 will not be realised by having an exclusive focus on achieving Target 6; it will also require that substantial progress is made with most GBF Targets. Elucidating the interconnectedness of different GBF Targets in relation to their direct or indirect role in the effective management of biological invasions reveals opportunities for a more integrated approach to biodiversity conservation. The inclusion of the multiple GBF targets in strategies to address invasive alien species is the step change needed to reduce the magnitude of this threat to biodiversity by 2030.

Urban areas are foci for the introduction of non‐native plant species, and they often act as launching sites for invasions into the wider environment. Although interest in biological invasions in urban areas is growing rapidly, and the extent and complexity of problems associated with invasions in these systems have increased, data on the composition and numbers of non‐native plants in urbanized areas remain scattered and idiosyncratic. We assembled data from multiple sources to create the Global Urban Biological Invasions Compendium (GUBIC) for vascular plants representing 553 urban centres from 61 countries across every continent except Antarctica. The GUBIC repository includes 8140 non‐native plant species from 253 families. The number of urban centres in which these non‐native species occurred had a log‐normal distribution, with 65.2% of non‐native species occurring in fewer than 10 urban centres. Practical implications : The dataset has wider applications for urban ecology, invasion biology, macroecology, conservation, urban planning and sustainability. We hope this dataset will stimulate future research in invasion ecology related to the diversity and distributional patterns of non‐native flora across urban centres worldwide. Further, this information should aid the early detection and risk assessment of potential invasive species, inform policy development and assist in setting management priorities.

Biological invasions are increasing globally, with species demonstrating differing responses to climate change in their native and invaded ranges. Investigating how alien species respond to climate change is important for planning management interventions. This study considered how the distribution of Sphaeropteris cooperi (Hook. ex F.Muell.) R.M.Tryon, a widely cultivated invasive tree fern with a broad climatic tolerance, could alter under climate change in two invaded southern hemisphere biodiversity hotspots: South Africa's Garden Route and La Reunion Island, Mascarene Archipelago. To determine the distributional changes of S. cooperi under future climate change scenarios, its niche dynamics were assessed in its native range (Australia) and two invaded southern hemisphere ranges using Schoener's statistic for niche overlap and principal component analyses. An ensemble modelling approach was used to predict the potential distribution of S. cooperi under future (2041-2070 and 2071-2100) carbon emission scenarios (SSP1-2.6 and SSP 5-8.5) using five global climate models. The results suggest that S. cooperi demonstrates some climatic niche overlap (17.6 %) between the Garden Route and its native range (Australia), but less overlap (3.7 %) was found between La Reunion Island and Australia. On La Reunion Island, little niche overlap together with niche expansion suggests that S. cooperi occupies niches not occupied in its native range, and that niche conservatism does not hold true for this location. Thus, under current climatic conditions, future spread may be anticipated in both the Garden Route and La Reunion Island. However, climatic conditions are shifting making it important to consider climate change when predicting how the range of this invader may change in the future. Species distribution models revealed that for both biodiversity hotspots, regardless of climatic scenario or the time frame considered, the range of S. cooperi is predicted to shrink, although the degree of decline is expected to vary with time and climate scenario. (c) 2025 The Authors. Published by Elsevier B.V. on behalf of SAAB. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

The One Health concept focuses on interactions between people, animals, plants and the environment, recognizing the interdependence of human, animal, plant and ecosystem health. This chapter applies the One Health approach to assess the effects of invasion by alien trees in the genus Prosopis on the four dimensions of health, drawing on research findings from eastern Africa and including, where appropriate, results from other parts of Africa. A review of the literature of Prosopis invasions shows that these invasions, while bestowing some benefits, have negative consequences on all dimensions of health, and that they are increasing in magnitude as the invasions grow. Negative consequences include injury and dietary or toxic impacts on people and animals, increase of vectors of zoonotic diseases, displacement of native plants through competition for limiting resources and allelopathy, and detrimental effects on the provision of ecosystem services by using excessive amounts of water and eliminating pasture grasses. This chapter proposes two approaches to assess the multidimensional impacts of Prosopis juliflora in a One Health context. First, an assessment of the impact of this invasive tree species on ecosystem service multifunctionality is presented, considering indicators of ecosystem services relating to all four dimensions of One Health. Second, the positive and negative aspects of P. julilfora are contrasted across the four dimensions to calculate a One Health score for different landscapes with varying degrees of invasion. Both approaches indicate that pristine or restored environments deliver positive benefits, but that heavily invaded sites are characterized by substantial changes in human, animal, plant and environmental health, a situation that is predominantly negative and unsustainable. Holistic assessments such as the approaches presented here will hopefully raise awareness of the gravity of the problem, thereby helping to secure the funding needed to contain and hopefully reverse the problems associated with these invasions.

Ageratina adenophora (Spreng.) R.M. King & H. Rob. (Crofton weed) is a triploid, apomictic perennial herb or sub-shrub native to Mexico that is highly invasive in many parts of the world. This species thrives in diverse habitats, from wet forest margins to dry slopes and disturbed urban areas. Initially introduced globally as an ornamental plant, it has now naturalized across many continents, including Europe, Asia, Africa, Oceania, and the Americas, often displacing native flora and altering ecosystems. Its introduction to Europe dates back to the 19th century, with naturalization first recorded on the French Riviera. Ageratina adenophora is now established in several southern European countries (Portugal, Spain, France, Italy, Croatia, Greece) and across the Macaronesian islands. It spreads via wind- and water-dispersed seeds and can also propagate vegetatively, particularly along riparian systems and disturbed sites. Despite its prolific reproduction and adaptability, its expansion in Europe has so far remained moderate, possibly due to climatic limitations and unsuitable habitats. Ecologically, A. adenophora exhibits remarkable phenotypic plasticity and physiological adaptations that enable it to survive a range of abiotic stresses including cold, drought, and variable light levels. The species benefits from mutualisms with soil microbes and displays enhanced nitrogen-use efficiency in introduced ranges. Although initially valued for ornamental and medicinal purposes, A. adenophora is now widely recognized as a harmful invader. It invades both natural and semi-natural habitats and has demonstrated a capacity to alter soil chemistry, suppress native vegetation through competition and allelopathy, and host diverse pathogens and endophytes. Ageratina adenophora negatively impacts biodiversity, ecosystem functioning, and agriculture by forming dense, monospecific stands and disrupting native communities. Its presence in biodiversity hotspots and protected areas-such as Himalaya, South Africa, and the Canary Islands-poses significant conservation challenges. Control efforts, including the use of biological agents such as Procecidochares utilis Stone 1947, have yielded mixed results. The most effective method for small areas is to physically remove A. adenophora before it sets seed. This can be done by hand-pulling or cutting. Given the continued spread and resilience of this species there is an urgent need for coordinated management strategies and increased awareness, especially in the face of climate change which may further facilitate its expansion in Europe and beyond.

Invasive species (IS) pose a global threat to biodiversity and human wellbeing. Managing this complex problem at the large scales required—across biomes, jurisdictions and land tenures—is challenging, particularly in developing countries. Innovative approaches that extend management beyond the remit of government are urgently needed. Initiatives which are not currently dominant, which exist at the margins of current mainstream practice, and which offer new ways of thinking and doing, may represent a promising source of inspiration and impact for IS management. Here we identify and analyse these so-called seeds in the context of IS management in South Africa, with the goal of understanding their contribution to IS management and to deeper transformative change. We examine what kinds of bottom-up innovations are currently present, what activities they involve and whom they benefit, what enablers and barriers they face, and in what ways they demonstrate transformative potential. We identified 37 seed initiatives, including technological solutions, alternative uses for IS, stewardship approaches and ways of engaging the public. Seeds are primarily enabled by their social connections, including broad collaborations, investing in networks, and in working with trusted mediators. Key barriers include misaligned or unstable government funding, inappropriate regulatory frameworks, and shortages of skilled personnel. These seed initiatives include many indicators of transformative change, including the ability to restructure systems, be innovative and be highly co-productive. We identify clusters of seeds representing different transformative strengths. This work provides a first insight into how marginal, experimental or bottom-up initiatives could contribute significantly to the impact of IS management in South Africa, and beyond. Supporting the scaling of these initiatives can contribute to transformative change towards more sustainable and just social-ecological futures.

Ligustrum is a genus of woody plants comprising 46 accepted species that have been widely moved around the world, with species showing varying levels of progression along the introduction-naturalisation-invasion continuum. Ligustrum species (privets) have been widely cultivated in South Africa as ornamental plants and have become naturalised and invasive in many areas. Little information is available on the introduction status, distribution, invasion ecology and impacts of privets in the country. We: 1) conducted a literature search to construct a timeline of Ligustrum introductions to South Africa; 2) assessed which species are currently present in the country; 3) evaluated the current distribution using multiple data sources and the potential distribution of L. lucidum and L. sinense using species distribution modelling; 4) provided insights on the invasion ecology of L. lucidum and L. sinense in the Stellenbosch urban area and along the Eerste River; and 5) conducted formal risk analyses for the five Ligustrum species listed in South Africa's alien and invasive species legislation (L. japonicum, L. lucidum, L. ovalifolium, L. sinense and L. vulgare). Fourteen Ligustrum taxa are known to have been introduced to South Africa, the earliest record being for L. japonicum in 1887. Ligustrum species were found in 151 quarter-degree cells (QDCs) across South Africa. The most widespread species are L. lucidum (138 QDCs), L. sinense (47 QDCs) and L. ovalifolium (21 QDCs). Ligustrum lucidum and L. sinensis are both widespread invaders (category E in the Blackburn framework for biological invasions), L. ovalifolium is widely naturalised (category D1) and the other taxa are all in category B2. The highest number of taxa in a single QDC was seven (in Pretoria, Gauteng) and the highest number of observations in a QDC was 485 (in Stellenbosch, Western Cape). Sixteen hotspots of naturalisation and invasion were identified around the country. A fine-scale study was conducted for the two Ligustrum species with the most comprehensive data (L. lucidum and L. sinense) around Stellenbosch. Climatic niches for L. lucidum and L. sinense in South Africa differed from those based on records elsewhere in the world. Predicted suitable areas for both L. lucidum and L. sinense spanned the eastern and southwestern parts of the country, although L. sinense had a smaller potential range in the east. In the local-scale study (Stellenbosch), Generalised Additive Models highlighted the importance of riparian habitats for the establishment of potentially invasive populations. Formal risk analyses for all five reviewed species (L. japonicum, L. lucidum, L. ovalifolium, L. sinense, and L. vulgare) yielded high-risk scores, highlighting the current and potential impacts of these species. Urgent attention is needed to manage the genus in South Africa, starting with a re-assessment of the legislative status of all taxa in the genus. (c) 2025 The Author(s). Published by Elsevier B.V. on behalf of SAAB. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

Plant invasiveness is influenced by various ecological and environmental factors, with high phenotypic plasticity and functional trait variation playing crucial roles. Functional traits provide a conceptual framework for understanding species distribution, community assembly, and the ecological impact of invasive species. This study hypothesized that specific plant functional traits facilitate the establishment and dominance of Ageratum conyzoides in urban landscapes. We tested this hypothesis by conducting field surveys across five urban habitat types within the Northern Irrigated Plains of Punjab, Pakistan: roadside verges, urban parks, wetlands, agricultural land, and abandoned land. Key morphological and physiological traits, including plant height, specific root length, dry leaf biomass, leaf area, specific leaf area, and leaf dry matter content, were measured in each habitat type. The Competitive Advantage Index (CAI) and Community Invasibility Index (CII) were calculated for each sampling plot, and soil physicochemical and textural properties were recorded. Statistical analyses, including Tukey’s post-hoc test, principal component analysis, correlation analysis, and polynomial regression, were used to evaluate trait and soil relationships. The results revealed that A. conyzoides exhibited greater plant height, leaf area, and specific leaf area in urban parks and roadside verges, where resource availability was higher. Functional trait variation across habitat types indicated that the species prioritized rapid growth and resource acquisition in disturbed environments, while in nutrient-limited habitats it adopted a more conservative strategy. Higher CAI values were associated with increased plant height, leaf area, and specific leaf area, indicating that such traits contributed to competitive dominance. Similarly, CII was positively correlated with soil organic matter, available phosphorus, and electrical conductivity, indicating that nutrient-enriched soils promote greater invasibility. Although soil texture (sand, silt, and clay content) showed weaker correlations with CII and CAI, its inclusion in the analysis provides a more comprehensive view, suggesting that while fertility plays a dominant role, physical properties may still influence invasion dynamics through interactions with water and nutrient availability. These findings demonstrated that A. conyzoides achieved invasion success by capitalizing on high resource availability and trait plasticity, particularly in urban environments with disturbed soils. Understanding the relationships between functional traits and environmental conditions offers critical insights into invasion ecology and can guide effective management strategies to curb the spread and impact of invasive species in urban landscapes.

The globalization of trade and increased human mobility have facilitated the introduction and spread of nonnative species, posing significant threats to biodiversity and human well-being. As centers of global trade and human populations, cities are foci for the introduction, establishment, and spread of nonnative species. We present a global synthesis of urban characteristics that drive biological invasions within and across cities, focusing on four axes: ( a ) connectivity, ( b ) physical properties, ( c ) culture and socioeconomics, and ( d ) biogeography and climate. Urban characteristics such as increased connectivity within and among cities, city size and age, and wealth emerged as important drivers of nonnative species diversity and spread, while the relative importance of biogeographic and climate drivers varied considerably. Elaborating how these characteristics shape biological invasions in cities is crucial for designing and implementing strategies to mitigate the impacts of invasions on ecological systems and human well-being.

Although invasive alien species have long been recognized as a major threat to nature and people, until now there has been no comprehensive global review of the status, trends, drivers, impacts, management and governance challenges of biological invasions. The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) Thematic Assessment Report on Invasive Alien Species and Their Control (hereafter 'IPBES invasive alien species assessment') drew on more than 13,000 scientific publications and reports in 15 languages as well as Indigenous and local knowledge on all taxa, ecosystems and regions across the globe. Therefore, it provides unequivocal evidence of the major and growing threat of invasive alien species alongside ambitious but realistic approaches to manage biological invasions. The extent of the threat and impacts has been recognized by the 143 member states of IPBES who approved the summary for policymakers of this assessment. Here, the authors of the IPBES assessment outline the main findings of the IPBES invasive alien species assessment and highlight the urgency to act now.

A large number of non‐native trees (NNTs) have been introduced globally and widely planted, contributing significantly to the world's economy. Although some of these species present a limited risk of spreading beyond their planting sites, a growing number of NNTs are spreading and becoming invasive leading to diverse negative impacts on biodiversity, ecosystem functions and human well‐being. To help minimize the negative impacts and maximize the economic benefits of NNTs, Brundu et al. developed eight guidelines for the sustainable use of NNTs globally—the Global Guidelines for the Use of NNTs (GG‐NNTs). Here, we used an online survey to assess perceptions of key stakeholders towards NNTs, and explore their knowledge of and compliance with the GG‐NNTs. Our results show that stakeholders are generally aware that NNTs can provide benefits and cause negative impacts, often simultaneously and they consider that their organization complies with existing regulations and voluntary agreements concerning NNTs. However, they are not aware of or do not apply most of the eight recommendations included in the GG‐NNTs. We conclude that effectively managing invasions linked to NNTs requires both more communication efforts using an array of channels for improving stakeholder awareness and implementation of simple measures to reduce NNT impacts (e.g. via GG‐NNTs), and a deeper understanding of the barriers and reluctance of stakeholders to manage NNT invasions. Read the free Plain Language Summary for this article on the Journal blog.

Mixed infections of Cassava brown streak virus (CBSV) and its Ugandan variant (UCBSV) in cassava hosts are increasingly threatening food security in East and Central Africa. The possibility of these viruses spreading to cassava producing countries in West Africa is of great concern. Most epidemiological models developed to address this challenge do not include the possibility of coinfection and whitefly lifecycle in managing these viruses. The question is: how does the inclusion of whitefly lifecycle and temperature variability influence disease outbreak and spread? We develop a host-vector-virus coinfection model that incorporates the whitefly life cycle and temperature variability as drivers of an epidemic. Using a combination of analytical and numerical simulations, we identify the key factors that drive disease outbreaks in cassava plantations. We also demonstrate that management of the whitefly's immature development stage can reduce disease prevalence and crop losses associated with these outbreaks. These results suggest that biological control agents using natural enemies should be given higher priority than the use of insecticides in management strategies.