Stable isotope analysis (SIA) is widely used to reconstruct food webs, characterize trophic relationships, and estimate dietary composition. However, bulk tissue SIA (BSIA) can yield imprecise estimates when dietary sources are isotopically similar. We compared carbon SIA of amino acids (delta C-13-EAA values) with BSIA (delta C-13 and delta N-15 values) to estimate diet composition and basal resource use of invasive house mice (Mus musculus) on Sand Island, part of a remote atoll in the north Pacific Ocean. We aimed to assess whether delta C-13-EAA values could improve source differentiation and yield more precise diet estimates and to evaluate whether delta C-13-EAA fingerprints could provide insights into the origin and use of basal resources by mice. We applied a Bayesian mixing model using delta C-13-EAA values from a subset of 10 mice and associated diet items, with sample selection guided by existing BSIA and next-generation sequencing datasets. Diet source estimates from the delta C-13-EAA model closely resembled those from the BSIA-based model (n = 90): arthropods dominated mouse diet, with smaller contributions from seabirds and plants. Estimates from the delta C-13-EAA model were more consistent and precise than those from a BSIA model using the same 10 individuals, underscoring the value of informed sample selection. Although use of delta C-13-EAA values did not substantially improve separation among isotopically similar sources, it reinforced our previous findings. We also used delta C-13-EAA fingerprinting to reconstruct basal resource use. Mice obtained most of their essential amino acids from aquatic basal resources-likely through direct consumption of seabird tissues or indirectly by eating scavenger arthropods-whereas terrestrial resources contributed far less. These findings highlight the ecological impact of mice on Sand Island, showing how they exploit energy and nutrients derived from marine subsidies. Collectively, our results suggest that delta C-13-EAA values are most effective when paired with pre-existing ecological knowledge, especially for omnivores in complex food webs. Applied judiciously, this method may strengthen ecological inferences and provide additional insights into impacts of invasive species-particularly in island ecosystems.

Nonnative plantations offer economic benefits but increase the risk of biological invasions worldwide. This risk is primarily driven by frequent anthropogenic disturbances and autocatalytic processes that can lead to an invasion meltdown, creating hotspots that amplify ecological impacts. This underscores the urgent need to balance economic benefits with ecosystem sustainability.

Tree invasions threaten native forests worldwide, yet little is known about how to prevent this process. To detect these invasions early it is vital to anticipate potential invaders: identifying traits of successful tree invaders in forests is key. The Pinaceae family is an ideal study system to identify which traits favor tree invasions in forests because many of its species were planted in forests across the world several decades ago and they include many plant traits potentially associated with invasion success. For 45 introduced Pinaceae species planted 100 years ago on an island dominated by native forests in Patagonia, and for the subset of 24 species naturalized on this island, we evaluated the relationship between traits (seed mass, maximum height, wood density, juvenile period and interval between large seed crops) and invasion incidence (whether a species has become invasive or not) or extent (number of invaded transects across the study area). We found that invasion incidence and extent increased with maximum height, decreased with seed mass, juvenile period, and interval between large seed crops, and was unaffected by wood density. These results were similar for both introduced and naturalized species pools. Taller trees with smaller seeds, which start producing seeds earlier and continuously, will produce more seeds that can disperse further (especially if released from greater heights), increasing the probability of finding suitable microsites for seedling establishment, and accelerating population spread. In this study system, we conclude that future introductions of non-native tree species to forests should focus on species with lower invasion risk: those with lower maximum height, bigger seeds, longer juvenile periods, and longer intervals between large seed crops.

The fifteenth Conference of the Parties to the Convention on Biological Diversity adopted four Global Goals for 2050 and 23 Targets for 2030. One concern has been the lack of a monitoring mechanism to measure the progress of countries in protecting biodiversity as a step towards the 2050 Goal of 'halting extinction'. Clearly defined conservation targets are essential. There is abundant quantitative evidence of human impacts. We ask three questions. (i) Does conservation slow global extinction rates? (ii) Does conservation rescue previously declining populations? (iii) What is the progress of protecting areas globally? Are such areas selected optimally to slow extinctions and reverse population declines? We find a disconnect between unsupported claims about impending planetary doom and carefully documented evidence of conservation's successes and failures. Certainly, gaps exist in our knowledge about biodiversity loss. Nonetheless, conservation has prevented extinctions and allowed some once-declining species to flourish. It protects ever-greater areas of land and ocean, often doing so in sensible places. Future success will depend on clearly defined metrics to measure what works and what does not. Such a recommendation resonates strongly with the work that Professor Dame Georgina Mace pioneered.

The pathways through which non-native species are introduced and spread help shape the rate and geographic patterns of biological invasions. These pathways can be classified as primary, where non-native species cross jurisdictional or biogeographic boundaries, or secondary, where species move within these boundaries after introduction. Despite fundamental economic, political, social, and ecological differences between these pathway types that affect the risk of species introductions and the prioritization of management responses, most classification schemes and regulatory frameworks do not explicitly distinguish between them. This lack of distinction is consequential: primary pathways are relatively well-defined and subject to biosecurity regulation, while secondary pathways remain poorly characterized and largely overlooked in policy and practice. Secondary pathways create multiple nodes from which non-native species spread, transporting individuals extensively and complicating containment efforts. Here we refine the distinction between primary and secondary pathways and explore their explicit separation in classification and management frameworks. We highlight how failing to recognize this distinction can limit the effectiveness of biosecurity systems, particularly by leaving secondary pathways inadequately addressed. Explicitly distinguishing these pathway types can help to improve invasive species control responses, strengthen cross-scale coordination efforts, reduce economic damage, and achieve global biodiversity goals.

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.

A popular hypothesis predicts that positive interactions involving non-native species will cause ecosystems to become more easily invaded and modified, resulting in an accumulation of invaders and their impacts—a process termed invasional meltdown. This model contrasts with the classical theory of biotic resistance, which emphasizes increasing antagonistic interactions among species as a community grows. Invasional meltdown can be an emergent consequence of serial or concomitant facilitations and their indirect effects. However, it has often been narrowly equated with simple biotic facilitation in which the establishment, population expansion, spread, or impact of one invader is enhanced through a positive interaction with another; the hypothesis has rarely been explored beyond these single pairwise facilitations. The original model emphasized continuous self-reinforcing effects of positive interactions of non-native species in general, but here we propose that invasional meltdown can arise through other mechanisms—including an influx of coevolved species, a cluster of interactions driven by a single keystone facilitator, and indirect interactions among both native and non-native species—all of which can result in an increasing invasion rate and cumulative, potentially synergistic impacts. Furthermore, invasional meltdowns are not likely to be indefinite; for example, they may be punctuated by periods in which the invaded community temporarily resists further invasion until a biotic or abiotic phenomenon disrupts the resistance and triggers another series of facilitations. Although invasional meltdown can potentially transform entire ecosystems, its ecological consequences at the community and ecosystem levels have rarely been tested, owing to the complexity of interactions and pathways involved.

With regard to the recent discovery of the red imported fire ant in Sicily (Menchetti et al. 2023), Genovesi et al. highlight the delay in communicating the observation and call on the scientific communities, scientific journals, and local authorities to ensure that new invasive alien species records are immediately reported for enhancing action.

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.

Journal Article Systematic and persistent bias against invasion science: Framing conservation scientists Get access Daniel Simberloff, Daniel Simberloff Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee, United States Email: tebo@utk.edu; dsimberloff@utk.edu https://orcid.org/0000-0002-1424-9291 Search for other works by this author on: Oxford Academic Google Scholar Alejandro Bortolus, Alejandro Bortolus Grupo de Ecología en Ambientes Costeros, Instituto Patagónico para el Estudio de los Ecosistemas Continentales, Puerto Madryn, Chubut, Argentina Search for other works by this author on: Oxford Academic Google Scholar James T Carlton, James T Carlton Coastal and Ocean Studies Program, Williams College-Mystic Seaport, Mystic, Connecticut, United States Search for other works by this author on: Oxford Academic Google Scholar Franck Courchamp, Franck Courchamp Department of Ecologie, Systématique, Evolution, Université Paris-Saclay, Gif-Sur-Yvette, France Search for other works by this author on: Oxford Academic Google Scholar Ross N Cuthbert, Ross N Cuthbert Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast, United Kingdom https://orcid.org/0000-0003-2770-254X Search for other works by this author on: Oxford Academic Google Scholar Philip E Hulme, Philip E Hulme Department of Pest-Management and Conservation, Lincoln University, Christchurch, New Zealand https://orcid.org/0000-0001-5712-0474 Search for other works by this author on: Oxford Academic Google Scholar Julie L Lockwood, Julie L Lockwood Department of Ecology, Evolution, and Natural Resources, Rutgers University, New Brunswick, New Jersey, United States https://orcid.org/0000-0003-0177-449X Search for other works by this author on: Oxford Academic Google Scholar Laura A Meyerson, Laura A Meyerson Department of Natural Resources Science, University of Rhode Island, Kingston, Rhode Island, United States Search for other works by this author on: Oxford Academic Google Scholar Martín A Nuñez, Martín A Nuñez Department of Biology and Biochemistry, University of Houston, Houston, Texas, United States Search for other works by this author on: Oxford Academic Google Scholar Anthony Ricciardi, Anthony Ricciardi Department of Biology, McGill University, Montreal, Quebec, Canada https://orcid.org/0000-0003-1492-0054 Search for other works by this author on: Oxford Academic Google Scholar ... Show more David M Richardson, David M Richardson Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa Search for other works by this author on: Oxford Academic Google Scholar Evangelina Schwindt Evangelina Schwindt Biología de Organismos Marinos, Puerto Madryn, Chubut, Argentina Search for other works by this author on: Oxford Academic Google Scholar BioScience, biae029, https://doi.org/10.1093/biosci/biae029 Published: 17 April 2024 Article history Received: 09 February 2024 Accepted: 14 March 2024 Published: 17 April 2024