Soil biodiversity is crucial to the maintenance of multiple critical ecosystem functions and services. However, remarkably little is known about the conservation status of most soil-dependent species. To better understand the current situation, we determined the number of soil-dependent species listed in the various categories of the IUCN Red List of Threatened Species. Firstly, a definition of soil-dependent species was developed for IUCN Red List purposes, and this definition facilitated the identification of 8,653 currently listed soil-dependent species. These species included 503 invertebrate and fungal species assessed during the current study; these species were chosen as they were based on priorities for the Red List Strategic Plan, and IUCN Species Survival Commission (SSC) Specialist Group interests. We discuss progress and constraints on the IUCN Red List assessment of soil-dependent species worldwide. Our recommendations for the IUCN SSC to improve the IUCN Red List as a source of information on conservation of soil-dependent species are: (1) scaling up of SSC assessment processes for soil-dependent invertebrates and fungi, including establishment of a Soil Biota Working Group, in line with the IUCN Red List Strategic Plan; (2) building closer connections with other organizations and agencies researching and monitoring soil biodiversity; and (3) broader engagement with and education of governments, landholders and the public as to the fundamental importance of the conservation of global soil biodiversity.

The IUCN Red List of Threatened Species, the most widely used global system for assessing species' extinction risk, has become a foundational source of information for conservation management, policy and research. Since the adoption of quantitative extinction risk criteria more than three decades ago, the Red List has expanded substantially in scope and influence, informing decisions ranging from species conservation and protected area designation to international agreements, corporate risk assessments and global biodiversity indicators. Given its central role, maintaining scientific rigour, transparency and trust in the Red List system is essential. Feedback from users, emerging from evolving applications and scientific advances, has shaped the Red List throughout. At the same time, the Red List has been subject to recurring critiques, some of which stem from persistent misconceptions about its purpose, design and appropriate use. To address these, we review the history and development of the Red List system, clarify the strengths of its design, delineate the contexts for which the system was and was not intended, and elucidate the circumstances under which it may be modified. Finally, we outline pathways for researchers and users to contribute to ongoing improvements and discuss potential future directions for evolution of the Red List.

The Red List is one of the most important and widely used sources of biodiversity information, providing conservation assessments for nearly 160,000 species. Here, we assess how the change in available Red List data can influence the selection of spatial conservation priorities and which regions are identified as most critical for conservation. We mapped biodiversity importance based on species ranges and threat status at similar to 25 km, similar to 50 km, and similar to 100 km resolutions for two time points: 2010 and 2023. We then analyzed shifts in the top 10 % and 25 % most important areas for biodiversity at global and national levels between the two time points. We find that, globally, conservation priorities shifted over time from higher-income to lower-income countries. Nationally, priority areas in 2010 and 2023 were on average 60 % retained and over 40 % of countries experienced a shift in over half of their priority areas between the two years. Beyond showing large shifts within countries of which areas would be the most important to preserve, our analysis highlights an increasing focus on biodiversity research in developing nations. These shifts showcase the uneven global sampling of biodiversity, which skews our understanding of where to invest to efficiently conserve nature. We recommend increased funding for geographically representative field data collection, and the inclusion of explicit guidelines for regular updates in biodiversity frameworks to ensure conservation strategies remain effective.

Taxonomic lists are important tools for efficient communication about biodiversity. The processes by which they are created and maintained need to be robust, scientifically sound, and transparent. Articulating and scoring a set of governance quality indicators provides a way to assess the relative strengths of list management, gives list users a means to assess the quality of this process, augments the information available to list aggregators, and allows patterns to be measured over time and among forms of life. Based on published principles, we created 12 governance quality indicators which we tested on 16 lists spanning a range of taxonomic groups. Independence of taxonomy from nomenclature scored most strongly, but scores for local and regional involvement were lower. The governance quality indicators may eventually provide a rubric for assessing best practice species list governance but now need a period of further testing, review, and refinement before they are institutionalized.

Abstract Halting and reversing biodiversity loss requires urgent implementation of effective conservation actions. There are global datasets on the implementation of conservation actions for species and the effectiveness of conservation actions. However, these data have never previously been combined to assess whether actions known to be most effective are the ones being implemented or are at least recognised as needed by conservationists and whether additional actions are potentially needed. To explore this, we used IUCN Red List data on the broad types of conservation actions in place or needed for 24,943 amphibian, bird and mammal species and combined these with assessments of the effectiveness of 1420 specific actions for these species groups from the Conservation Evidence database. For each broad type of conservation action (e.g. land/water management), we compared the percentage of species with each action documented as in place or needed with the percentage of specific actions (e.g. tree planting) that are likely to be effective. We also identified potentially beneficial conservation actions for species with documented threats or small populations. We found evidence that most broad types of conservation action can be effective. Land/water protection was the most frequently documented in place and needed action, with many species also needing but lacking land/water management. Despite law and policy, compliance and enforcement, and awareness and communication actions being frequently documented, these and other enabling actions have fewer studies of their effectiveness in Conservation Evidence. Many species of concern may benefit from additional actions beyond those documented, largely to tackle negative impacts of agriculture and biological resource use. Where we lack knowledge of effective approaches, experimental tests and alternative evaluation approaches may be necessary to understand their impact, and practitioner insights may help guide implementation of such actions. Synthesis and applications: Our study demonstrates the power of combining differently‐sourced and compiled datasets to evaluate the likely effectiveness of ongoing conservation strategies and identify future needs. Our findings can inform species action plans and conservation spatial‐planning tools, helping to ensure that future conservation efforts are evidence‐based, have greater impact and ultimately lead to biodiversity recovery.

Freshwater ecosystems are highly biodiverse1 and important for livelihoods and economic development2, but are under substantial stress3. To date, comprehensive global assessments of extinction risk have not included any speciose groups primarily living in freshwaters. Consequently, data from predominantly terrestrial tetrapods4,5 are used to guide environmental policy6 and conservation prioritization7, whereas recent proposals for target setting in freshwaters use abiotic factors8, 9, 10, 11, 12-13. However, there is evidence14, 15, 16-17 that such data are insufficient to represent the needs of freshwater species and achieve biodiversity goals18,19. Here we present the results of a multi-taxon global freshwater fauna assessment for The IUCN Red List of Threatened Species covering 23,496 decapod crustaceans, fishes and odonates, finding that one-quarter are threatened with extinction. Prevalent threats include pollution, dams and water extraction, agriculture and invasive species, with overharvesting also driving extinctions. We also examined the degree of surrogacy of both threatened tetrapods and freshwater abiotic factors (water stress and nitrogen) for threatened freshwater species. Threatened tetrapods are good surrogates when prioritizing sites to maximize rarity-weighted richness, but poorer when prioritizing based on the most range-restricted species. However, they are much better surrogates than abiotic factors, which perform worse than random. Thus, although global priority regions identified for tetrapod conservation are broadly reflective of those for freshwater faunas, given differences in key threats and habitats, meeting the needs of tetrapods cannot be assumed sufficient to conserve freshwater species at local scales.

Africa boasts high biodiversity while also being home to some of the largest and fastest-growing human populations. Although the current environmental footprint of Africa is low compared to other continents, the population of Africa is estimated at around 1.5 billion inhabitants, representing nearly 18% of the world’s total population. Consequently, Africa’s rich biodiversity is under threat, yet only 19% of the landscape and 17% of the seascape are under any form of protection. To effectively address this issue and align with the Convention on Biological Diversity’s ambitious ‘30 by 30’ goal, which seeks to protect 30% of the world’s land and oceans by 2030, substantial funding and conservation measures are urgently required. In response to this critical challenge, as scientists and conservationists working in Africa, we propose five recommendations for future directions aimed at enhancing biodiversity conservation for the betterment of African society: (i) accelerate data collection, data sharing and analytics for informed policy and decision-making; (ii) innovate education and capacity building for future generations; (iii) enhance and expand protected areas, ecological networks and foundational legal frameworks; (iv) unlock creative funding channels for cutting-edge conservation initiatives; and (v) integrate indigenous and local knowledge into forward-thinking conservation strategies. By implementing these recommendations, we believe Africa can make significant strides towards preserving its unique biodiversity, while fostering a healthier society, and contributing to global conservation efforts. This article is part of the discussion meeting issue ‘Bending the curve towards nature recovery: building on Georgina Mace's legacy for a biodiverse future’.

The Red List Index (RLI) is an indicator of the average extinction risk of groups of species and reflects trends in this through time. It is calculated from the number of species in each category on the IUCN Red List of Threatened Species, with trends influenced by the number moving between categories when reassessed owing to genuine improvement or deterioration in status. The global RLI is aggregated across multiple taxonomic groups and can be disaggregated to show trends for subsets of species (e.g. migratory species), or driven by particular factors (e.g. international trade). National RLIs have been generated through either repeated assessments of national extinction risk in each country or through disaggregating the global index and weighting each species by the proportion of its range in each country. The RLI has achieved wide policy uptake, including by the Convention on Biological Diversity and the United Nations Sustainable Development Goals. Future priorities include expanding its taxonomic coverage, applying the RLI to the goals and targets of the Kunming-Montreal Global Biodiversity Framework, incorporating uncertainty in the underlying Red List assessments, integrating into national RLIs the impact of a country on species' extinction risk abroad, and improving analysis of the factors driving trends.This article is part of the discussion theme issue 'Bending the curve towards nature recovery: building on Georgina Mace's legacy for a biodiverse future'.

Understanding the consequences of past conservation efforts is essential to inform the means of maintaining and restoring species. Data from the IUCN Red List for 67,217 animal species were reviewed and analyzed to determine (i) which conservation actions have been implemented for different species, (ii) which types of species have improved in status and (iii) which actions are likely to have driven the improvements. At least 51.8% (34,847) of assessed species have actions reported, mostly comprising protected areas (82.7%). Proportionately more actions were reported for tetrapods and warm-water reef-building corals, and fewer for fish, dragonflies and damselflies and crustaceans. Species at greater risk of extinction have a wider range of species-targeted actions reported compared with less threatened species, reflecting differences in documentation and conservation efforts. Six times more species have deteriorated than improved in status, as reflected in their IUCN Red List category. Almost all species that improved have conservation actions in place, and typically were previously at high risk of extinction, have smaller ranges and were less likely to be documented as threatened by hunting and habitat loss or degradation. Improvements in status were driven by a wide range of actions, especially reintroductions; for amphibians and birds, area management was also important. While conservation interventions have reduced the extinction risk of some of the most threatened species, in very few cases has full recovery been achieved. Scaling up the extent and intensity of conservation interventions, particularly landscape-scale actions that benefit broadly distributed species, is urgently needed to assist the recovery of biodiversity.

AbstractUnderstanding the consequences of past conservation efforts is essential to inform the means of maintaining and restoring species. Data from the IUCN Red List for 67,217 comprehensively assessed animal species were reviewed and analysed to determine (i) which conservation actions have been implemented for different species, (ii) which types of species have improved in state and (iii) which actions are likely to have driven the improvements. At least 51.8% (34,847) of assessed species have actions reported, mostly comprising protected areas (82.7%), with more actions reported for both terrestrial tetrapods and warm-water reef-building corals and fewer for fish, dragonflies and damselflies and crustaceans. Species at greater risk of extinction have a wider range of species-targeted actions reported compared to less threatened species, reflecting differences in documentation and conservation efforts. Six times more species have deteriorated rather than improved in their Red List category. Almost all species that improved have conservation actions in place; species that improved in state typically were historically at high risk of extinction, have smaller ranges and lacked a range of reported threats, particularly hunting and habitat loss or degradation. All types of conservation action were associated with improvements in state, especially reintroductions and invasive species control, alongside, for amphibians and birds, area management. This suggests a range of conservation interventions have successfully conserved some species at greatest risk but have rarely recovered populations to resilient levels. Scaling up the extent and intensity of conservation interventions, particularly landscape-scale actions that benefit broadly distributed species, is urgently needed to assist the recovery of biodiversity.

Systematic assessments of species extinction risk at regular intervals are necessary for informing conservation action 1 , 2 . Ongoing developments in taxonomy, threatening processes and research further underscore the need for reassessment 3 , 4 . Here we report the findings of the second Global Amphibian Assessment, evaluating 8,011 species for the International Union for Conservation of Nature Red List of Threatened Species. We find that amphibians are the most threatened vertebrate class (40.7% of species are globally threatened). The updated Red List Index shows that the status of amphibians is deteriorating globally, particularly for salamanders and in the Neotropics. Disease and habitat loss drove 91% of status deteriorations between 1980 and 2004. Ongoing and projected climate change effects are now of increasing concern, driving 39% of status deteriorations since 2004, followed by habitat loss (37%). Although signs of species recoveries incentivize immediate conservation action, scaled-up investment is urgently needed to reverse the current trends.

The IUCN Red List of Threatened Species underpins much decision-making in conservation and plays a key role in monitoring the status and trends of biodiversity. However, the shortage of funds and assessor capacity slows the uptake of novel data and techniques, hampering its currency, applicability, consistency and long-term viability. To help address this, we developed sRedList, a user-friendly online platform that assists Red List assessors through a step-by-step process to estimate key parameters in a standardised and reproducible fashion. Through the platform, assessors can swiftly generate outputs including species' range maps, lists of countries of occurrence, lower and upper bounds of area of occupancy, habitat preferences, trends in area of habitat, and levels of fragmentation. sRedList is compliant with the IUCN Red List guidelines and outputs are interoperable with the Species Information Service (SIS; the IUCN Red List database) in support of global, regional and national assessments and reassessments. sRedList can also help assessors prioritise species for reassessment. sRedList was released in October 2023, with a complete documentation package (including text documentation, ‘cheatsheets’, and 15 video tutorials), and will soon be highlighted in the official Red List online training course. sRedList will help to bridge the gap between extinction risk research and Red List assessment practice, increase the taxonomic coverage and consistency of assessments, and ensure the IUCN Red List is up-to-date to best support conservation policy and practice across the world.

The true state of ocean biodiversity is difficult to assess, and there are few global indicators to track the primary threat of overfishing. We calculated a 50-year Red List Index of extinction risk and ecological function for 1199 sharks and rays and found that since 1970, overfishing has halved their populations and their Red List Index has worsened by 19%. Overfishing the largest species in nearshore and pelagic habitats risks loss of ecomorphotypes and a 5 to 22% erosion of functional diversity. Extinction risk is higher in countries with large human coastal populations but lower in nations with stronger governance, larger economies, and greater beneficial fisheries subsidies. Restricting fishing (including incidental catch) and trade to sustainable levels combined with prohibiting retention of highly threatened species can avert further depletion, widespread loss of population connectivity, and top-down predator control.

Identifying and assessing the magnitude of direct threats to ecosystems and species are critical steps to prioritizing, planning, implementing, and assessing conservation actions. Just as medical clinicians and researchers need a standard way to talk about human diseases, conservation practitioners and scientists need a common and comprehensive language to talk about the threats they are facing to facilitate joint action, evaluation, and learning. To meet this need, in 2008 the IUCN Species Survival Commission and the Conservation Measures Partnership produced the first version of a common threats classification with the understanding that it would be periodically updated to take into account new information and learning. We present version 4.0 of this classification. For this latest update, we reviewed existing versions and derivatives of the original classification, over 1000 citations of the classification, threats data from over 2900 real-world conservation projects, and comments from many users. Based on our findings, we made changes to the threats classification scheme, including addition of a level 0 threat class, refinement of levels 1 and 2 threat categories, and addition of the threat “Fencing & walls” to level 2. Also added were level 3 threat types and modifiers that provide a more detailed description of different types of direct threats and thus allow users to fine-tune analyses and actions. The update also clarifies how to treat various stressors, including natural disaster events and climate change. As a result of these changes, we revised the formal definition of direct threats. They include human actions that are the direct cause of ecosystem or species-population degradation and loss, such as agriculture, transport, natural resource use, and ecosystem management. They also include ultimate stressors in natural systems whose dynamics have been altered by the effects of current or historical human actions, such as invasive or problematic native species, pollution, natural disasters, and climate change.

Overexploitation is a major threat to biodiversity and international trade in many species is regulated through the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). However, there is no established method to systematically determine which species are most at risk from international trade to inform potential trade measures under CITES. Here, we develop a mechanism using the International Union for Conservation of Nature’s Red List of Threatened Species to identify species that are likely to be threatened by international trade. Of 2,211 such species, CITES includes 59% (1,307 species), leaving two-fifths overlooked and in potential need of international trade regulation. Our results can inform deliberations on potential proposals to revise trade measures for species at CITES Conference of the Parties meetings. We also show that, for taxa with biological resource use documented as a threat, the number of species threatened by local and national use is four times greater than species likely threatened by international trade. To effectively address the overexploitation of species, interventions focused on achieving sustainability in international trade need to be complemented by commensurate measures to ensure that local and national use and trade of wildlife is well-regulated and sustainable.

The assessment region - the Arabian Peninsula - contains a wide diversity of sand and gravel deserts, mountains, coastal and offshore habitats and sparse wetlands. It also contains a diverse mammal fauna which comprises a mix of Arabian endemics, species with affinities to the Horn of Africa and Saharo-Sindian, Iranian-Central Asian, and Mediterranean elements. There are 166 terrestrial and 23 marine species whose occurrence in the region is confirmed, giving an overall total of 189 confirmed species. The status of the terrestrial species was assessed using the IUCN Red List Categories and Criteria and application of the IUCN Regional Guidelines. The distribution and status of each marine mammal species was reviewed and updated.

Biodiversity loss is a major global challenge and minimizing extinction rates is the goal of several multilateral environmental agreements. Policy decisions require comprehensive, spatially explicit information on species' distributions and threats. We present an analysis of the conservation status of 14,669 European terrestrial, freshwater and marine species (ca. 10% of the continental fauna and flora), including all vertebrates and selected groups of invertebrates and plants. Our results reveal that 19% of European species are threatened with extinction, with higher extinction risks for plants (27%) and invertebrates (24%) compared to vertebrates (18%). These numbers exceed recent IPBES (Intergovernmental Platform on Biodiversity and Ecosystem Services) assumptions of extinction risk. Changes in agricultural practices and associated habitat loss, overharvesting, pollution and development are major threats to biodiversity. Maintaining and restoring sustainable land and water use practices is crucial to minimize future biodiversity declines.

Comprehensive assessments of species' extinction risks have documented the extinction crisis(1) and underpinned strategies for reducing those risks(2). Global assessments reveal that, among tetrapods, 40.7% of amphibians, 25.4% of mammals and 13.6% of birds are threatened with extinction(3). Because global assessments have been lacking, reptiles have been omitted from conservation-prioritization analyses that encompass other tetrapods(4-7). Reptiles are unusually diverse in arid regions, suggesting that they may have different conservation needs(6). Here we provide a comprehensive extinction-risk assessment of reptiles and showthat at least 1,829 out of 10,196 species (21.1%) are threatened-confirming a previous extrapolation(8) and representing 15.6 billion years of phylogenetic diversity. Reptiles are threatened by the same major factorsthat threaten othertetrapods-agriculture, logging, urban development and invasive species-although the threat posed by climate change remains uncertain. Reptiles inhabiting forests, where these threats are strongest, are more threatened than those in arid habitats, contrary to our prediction. Birds, mammals and amphibians are unexpectedly good surrogates for the conservation of reptiles, although threatened reptiles with the smallest rangestend to be isolated from other threatened tetrapods. Although some reptiles-including most species of crocodiles and turtles-require urgent, targeted action to prevent extinctions, efforts to protect other tetrapods, such as habitat preservation and control of trade and invasive species, will probably also benefit many reptiles.

Biodiversity is not evenly distributed across the globe and some areas have greater potential to contribute to biodiversity conservation than others. Whilst there are multiple ways to determine priority areas for conservation, for a global institution like the Global Environment Facility (GEF), the funding mechanism for the Convention on Biological Diversity and the largest multilateral source of funding for developing countries focused on enhancing biodiversity outcomes and promoting sustainable use, it is important to fund the top-ranked countries whilst also ensuring that all eligible countries are able to undertake some biodiversity conservation actions in accordance with the Convention. To this end, the GEF uses the System for Transparent Allocation of Resources (STAR) to allocate funding in separate funding rounds to eligible countries. This country focus means that all prioritization analyses need to be undertaken within that political framework, while also considering the intrinsic patterns in biodiversity that don’t respect national borders. We present the 2018 update of the biodiversity component of GEF-STAR, investigate how the weighting system affects the ranking of countries. We show that top ranked and bottom ranked countries are robust to changes in the weighting of analytical elements, but the weighting can significantly alter the importance of middle ranking countries, affecting their funding allocation. This analysis has been used by the GEF, along with other data, to allocate over $1 billion in biodiversity funding (GEF-7 = $1.2 billion) to improve country and global prospects for conservation. However, this large funding allocation for conservation needs to be set against the vastly larger funding flows that decrease natural values around the world, and the need for systems level change remains evident across the entire planet.

In 2021, the International Union for Conservation of Nature (IUCN) introduced a novel method for assessing species recovery and conservation impact: the IUCN Green Status of Species. The Green Status standardizes recovery using a metric called the Green Score, which ranges from 0% to 100%. This study focuses on one crucial step in the Green Status method-the division of a species' range into so-called "spatial units"-and evaluates whether different approaches for delineating spatial units affect the outcome of the assessment (i.e., the Green Score). We compared Green Scores generated using biologically based spatial units (the recommended method) to Green Scores generated using ecologically based or country-based spatial units for 29 species of birds and mammals in Europe. We found that while spatial units delineated using ecoregions and countries (fine-scale) produced greater average numbers of spatial units and significantly lower average Green Scores than biologically based spatial units, coarse-scale spatial units delineated using biomes and countries above a range proportion threshold did not differ significantly from biologically based results for average spatial unit number or average Green Score. However, case studies focusing on results for individual species (rather than a group average) showed that, depending on characteristics of the species' distribution, even these coarse-scale delineations of ecological or country spatial units often over- or under-predict the Green Score compared to biologically based spatial units. We discuss cases in which the use of ecologically based or country-based spatial units is recommended or discouraged, in hopes that our results will strengthen the new Green Status framework and ensure consistency in application.