Understanding how an endangered species inhabits and utilises its environment is crucial for establishing effective conservation priorities. Assessing how the number of mature individuals in nature (density) and the Area of Occupancy (AOO) change over time are among the criteria used to determine a species’ conservation status on the IUCN Red List. The Black-hooded Antwren Formicivora erythronotos, a globally threatened and endemic bird from the Atlantic Forest, went unrecorded for more than 100 years until it was rediscovered in 1987; however, no systematic empirical studies have been carried out on its conservation status since then. We surveyed the species’ occurrence at 229 counting points distributed across 15 localities and recorded its presence at 61 points located in only three valleys, with an estimated Extent of Occurrence of 177.2 km2 and an Area of Occupancy (AOO) of 55km2. We also estimate the species density in two areas of Mambucaba Valley at 11 and 25 individuals km-2, respectively. These results were obtained from systematic data collection that will allow comparisons with future monitoring, facilitating understanding of changes in the species’ population density over time. This information is essential for reassessing the species’ conservation status and guiding conservation efforts.

Environmental water delivery is implemented globally to redress the ecological impacts of river regulation and consumptive water use. Allocation must balance the competing (and often conflicting) needs of humans, a diversity of water-dependent species and abiotic processes in the managed system. To optimize water allocation for conservation we developed a novel optimization framework that integrated a genetic algorithm with an integrated systems model to refine near-optimal allocations that maximize outcomes for a shrub (Duma florulenta), tree (Eucalyptus camaldulensis) and tree frog (Ranoidea raniformis) in one of the world’s most regulated catchments: the Murray–Darling Basin (Australia). Our algorithm weighted 16 wetland attributes and optimized those weights to prioritize allocation over a 25-year forecast window. The best-performing solutions required no additional resources but improved outcomes for the two priority plants and doubled the surviving frog populations. Modifying the multi-user model to only consider R. raniformis improved outcomes for that species at the expense of the two plant species, highlighting the risks of allocating a shared resource through a single-species lens. We demonstrate the value of optimization and multi-species approaches as decision-support tools for environmental water allocation and similar resource allocation problems in conservation.

Historical evidence suggests that the Vulnerable Mediterranean monk seal Monachus monachus, one of the most threatened pinniped species, commonly used to haul out on open beaches. However, in recent times, probably driven by increased human disturbance, the species tends to seek refuge in remote marine caves, typically those that include one or more entrances above or below water level, an entrance corridor, an internal pool, and a beach that provides a dry haul-out area. Here we present evidence of monk seals using a bubble cave, an air-filled chamber or dome, accessible through an underwater passage, where seals remain in the water without any platform or beach to haul out. These wet, less accessible and inconspicuous domes may not only provide refuge against human disturbance but also play a role as resting sites, complementing breeding and haul-out caves. The observations reported here suggest that habitat suitability studies for the Mediterranean monk seal may benefit from including bubble caves, as they provide valuable resting spots, especially in tourist areas where seals may be exposed to human disturbance.

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.

Rediscoveries of endemic plant species previously believed lost recalibrate conservation priorities by revealing relict populations and underscore the need for botanical surveys. Since its description in 1927, Ravenea latisecta, a palm species endemic to Madagascar, had been considered lost for nearly a century. Numerous palm collections failed to find wild populations, raising doubts about its existence. During a 2024 botanical survey in the Andasibe region, we rediscovered the species in Vohimana Reserve, Analamazoatra–Mantadia National Park and Vakona Forest private reserve. We recorded a total of 28 individuals within a limited area of c. 50 km2. Our findings suggest a provisional categorization as Critically Endangered on the IUCN Red List. All known individuals are located within protected areas, under various management regimes. Monitoring will be essential to evaluate potential threats, track population dynamics and study the species’ reproductive biology. This rediscovery highlights the critical role of fieldwork in Madagascar, where species believed lost may persist in overlooked forest patches. Our rediscovery shows that conserving even small forest remnants can safeguard species, and has conservation implications: integrated strategies are needed to secure the future of narrowly endemic palm species.

Mexico ranks third globally in seabird diversity and second in the number of endemic species that breed within its territory, yet 16% of seabird species in the country are categorized as threatened on the IUCN Red List, including the Critically Endangered Townsend’s shearwater Puffinus auricularis. Nearly 20 years ago, the breeding population of Townsend’s shearwater, which is endemic to the Revillagigedo Archipelago of Mexico, was inferred to comprise < 100 breeding pairs. Since then, conservation initiatives have been implemented in the archipelago. We assessed the current status of Townsend’s shearwater by mapping the distribution of breeding colonies, estimating breeding population size, evaluating reproductive success, describing ongoing threats and modelling population trends under three conservation scenarios. During 2016–2024, we conducted field surveys on the islands of Socorro and Clarión using acoustic monitoring techniques in historical nesting areas. We estimated that the breeding population on Socorro comprises < 200 pairs and documented the return of a small breeding population to Clarión after a 30-year absence. However, reproductive failure persists because of the effects of native predators such as land crabs, snakes and ravens. The population has exhibited a slow decline driven by interactions between native and invasive species. Without ongoing restoration efforts and management actions, including the removal of feral cats, the population could face extinction.

Understanding demographic processes is critical for conserving threatened epiphytes, yet detailed population studies remain rare. We analysed population dynamics in the context of phorophyte structure of the threatened orchid Cattleya quadricolor, endemic to Colombian tropical dry forest, to identify conservation priorities across eight fragmented subpopulations. Using stage-structured population projection models, we estimated both asymptotic growth rates (λ) and transient dynamics to assess long-term persistence and short-term vulnerability. Across all sites, λ values were consistently < 1, demonstrating that populations are in decline. Demographic structure was strongly skewed towards adult individuals, with seedling and juvenile stages strikingly underrepresented, suggesting recruitment failure as a major population bottleneck. Transient analyses further revealed limited capacity for short-term recovery after disturbance, especially in small populations. Phorophyte composition further influenced risk, as small host trees provide less stable substrates and greater accessibility to collectors, exacerbating vulnerability. Conservation priorities therefore differ amongst populations. In some sites, immediate protection of adult plants, targeted management of phorophyte assemblages and stronger enforcement against illegal collection are most urgent. In others, actions to enhance seedling recruitment, establish ex situ collections and reinforce reintroduction programmes are critical to buffer populations against extinction risk. By integrating asymptotic and transient demographic models with habitat context, our study demonstrates a comprehensive framework for evidence-based conservation of rare epiphytes, and underscores the importance of demographic approaches and phorophyte context for guiding orchid conservation in fragmented tropical dry forests.

We report the rediscovery of two endemic tree species of the genus Myrcia (Myrtaceae) in the Brazilian Atlantic Forest in 2021–2022. Both Myrcia colpodes and Myrcia rubiginosa were previously known from a small number of specimens collected mostly in the 19th century in the Metropolitan Region of Rio de Janeiro state in Brazil. Living specimens had not been recorded since 1958 and 2005, respectively. We provide here photographic documentation and updated risk assessments for both species, which will be submitted to IUCN for a formal assessment. Our findings illustrate that rare species that have not been collected for long periods can sometimes be found in plain sight in urban forest fragments. We also highlight the importance of protected areas for the conservation of forest trees, in particular rediscovered species. We recommend a number of conservation actions and encourage the Brazilian government, scientific institutions and civil society to acknowledge the importance of these species and to act to safeguard their future.

The bush dog Speothos venaticus, a short-legged, medium-sized Neotropical canid, remains elusive despite its wide geographical range. We present the first documented occurrence of this species within Rio Doce State Park, Minas Gerais state, Brazil. This Park is a unique, well-preserved area with a diverse array of mammal species, a rarity in the fragmented Atlantic Forest. We recorded the bush dog after 7,744 camera-trap days near Lagoa dos Patos, one of the Park’s lakes. This new record is a significant range extension for the species within the Atlantic Forest of Minas Gerais state, as the nearest known record is c. 420 km to the south. The new record is the northernmost documented occurrence of the bush dog in the Brazilian Atlantic Forest. This finding is a significant addition to the Park’s mammalian carnivore community, and underscores its importance as high-quality habitat for rare species such as the bush dog, and its value for scientific research and biodiversity conservation.

Indonesia is home to a high number of Critically Endangered land vertebrates. Examining the research on these species is important to improve biodiversity-related policy and management and to provide insight into knowledge gaps. We conducted a comprehensive review of 2,188 publications published during 2000–2021 that studied the Critically Endangered vertebrate species of Indonesia, to understand variations in the level of research on each species and the proportion of research carried out within Indonesia and by Indonesian researchers. Over this 22-year period, research on Critically Endangered species in Indonesia increased, but > 50% of this research was carried out by researchers based outside Indonesia. Moreover, the quantity of research was uneven across taxonomic classes, indicating an imbalance in research attention. Most publications during the period were on mammals (1,573 publications), followed by reptiles (310), birds (300) and amphibians (5). We identified 17 species for which there were no significant publications, suggesting little attention has been given to these species. We highlight three key issues: limited Indonesian authorship, taxonomic bias towards mammals and birds, and a need to address these challenges in authorship and bias. The low number of publications on many Critically Endangered land vertebrates reflects a lack of research effort, mostly because of limited funds and unequal conservation attention.

Iberodes littoralis subsp. gallaecica (Laínz) M. Serrano, R. Carbajal & S. Ortiz is a small annual plant endemic to dune systems in the north-west Iberian Peninsula. It is categorized as Endangered on the IUCN Red List and is a priority taxon under the EU Habitats Directive. Nevertheless, the only comprehensive census of this subspecies was conducted in 2009. Here we present the results of a new survey conducted in 2023 that adds a new location to its known range. Comparison with the previous census suggests that both the total population and area of occupancy have increased. However, these changes were not uniform across the range of the subspecies, with populations increasing at the northern and southern extremes and populations at central sites remaining stable or decreasing. Spatial differences in climate, anthropogenic pressures, plant performance and/or random fluctuations may explain these interpopulation variabilities. Given that the majority of populations are already located within the EU Natura 2000 network, we recommend that the current level of protection be maintained and that the plant be reintroduced into dune systems from which it has recently disappeared. Despite the increase in the total population, we recommend that the plant be recategorized as Critically Endangered given that its area of occupancy is small. Further censuses over time will be needed to provide information on population dynamics, trends, fluctuations and responses to environmental variables.

Spix’s Macaw Cyanopsitta spixii, extinct in the wild since 2000, was successfully reintroduced in Brazil in 2022, leading to significant progress, including the hatching of wild chicks. However, recent restrictions on further releases by the Brazilian government have put the reintroduction programme into jeopardy. This study updates our 2023 population viability analysis (PVA) to assess the impact of these delayed releases on the wild population. Using six modelled scenarios, we confirm that without annual supplementation of captive-bred birds, the probability of extinction in the wild remains at 100%. Even a one-time release is insufficient to secure population stability. Our results highlight that those annual releases of at least 20 individuals are necessary to ensure long-term viability, with reduced but still essential growth achievable with 10 birds per year. Supplementation of the wild population does not compromise the long-term viability of the well-established captive population. We urge immediate action to resume the release programme in 2024 to prevent the species from once again facing extinction in the wild.

The Secretarybird Sagittarius serpentarius is a charismatic raptor of the grasslands and open savannas of Africa. Evidence of widespread declines across the continent has led to the assessment that the species is at risk of becoming extinct. Southern Africa was identified as a remaining stronghold for the species, but the status of this population requires reassessment. To determine the status of the species in South Africa, Lesotho, and Eswatini, we analysed data from a citizen science project, the Southern African Bird Atlas Project (SABAP). We implemented novel time-to-detection modelling, as well as summarisation of changes in reporting rates, using standard metrics, to determine the trajectory of the population. To cross-validate our findings, we used data from another citizen science project, the Coordinated Avifaunal Roadcounts (CAR) project. While our results were in agreement with previous studies that have reported significant declines when comparing SABAP1 (1987–1992) and SABAP2 (2007 and onwards), all analysis pathways that examined data within the SABAP2 period only, as well as CAR data from this period, failed to show an alarming declining trend over this more recent time period. We did, however, find some evidence for decreases in Secretarybird abundance in urban grid cells. We used random forest models to predict probability of occurrence, as well as probability of abundance (reporting rates) for the assessed region and provided population estimates based on these analysis pathways. Continued monitoring and conservation efforts are required to guard this population stronghold.

Despite thousands of individuals entering the illegal wildlife trade each year, assessments of pangolin populations are largely non-existent, even in areas with high exploitation and limited personnel and field equipment. Although pangolins have unique keratin-based scales, there is no universal scale-marking method for individuals despite some pangolin conservation programmes utilizing marking for reference and cataloguing. Each programme currently establishes and manages its own system, resulting in inconsistencies and limiting data sharing. To facilitate pangolin monitoring and research, we developed a standardized method for assigning individual identification numbers, which we call the Pangolin Universal Notching System. This system is neither resource nor training intensive, which could facilitate its adoption and implementation globally. Its application could help to address knowledge gaps in pangolin ageing, reproduction, survivorship, migration and local trafficking patterns, and could be used in combination with other tagging techniques for research on pangolin biology.

Living plant collections play a crucial role in ex situ conservation, but their conservation value hinges on assessment of their composition, data quality and on strategic planning for optimization of the collection that takes into account species diversity, conservation status and allocation of resources. Cactaceae is one of the most threatened plant families globally and has a broad distribution in Brazil, with two of the seven centres of diversity for this group and a total of 276 known species. Climate change could escalate the threat to cacti, potentially placing 90% of species at risk by 2050. We conducted a case study of Cactaceae in the living Cactarium collection of the Rio de Janeiro Botanic Garden, evaluating the diversity of the collection and recommending strategic actions to enhance its conservation value. In 2022, we inventoried all specimens in the collection and cross-referenced them with the institutional specimen registry system, Jabot. The collection contains 156 cacti species that naturally occur in Brazil (57% of the total), including 43 species categorized as threatened on the Brazilian Red List and 57 categorized as threatened on the IUCN Red List. We recommend research to map cacti species that are threatened but not covered by in situ conservation in the country, list the priority species for acquisition by the collection, and make recommendations that will facilitate improved contribution of the Rio de Janeiro Botanic Garden to the conservation of the Brazilian flora.

Patterns of extinction risk can vary across taxa, with species of some groups being particularly vulnerable to extinction. Rails (Aves: Rallidae) represent one of the most extreme yet well-documented cases of mass extinction within a modern vertebrate group. Between 54 and 92% of rail species became extinct following waves of human contact during both the Holocene and the Anthropocene eras, and a third of the extant species are currently threatened or near-threatened. Here, we (1) examine extinction filters through consecutive human contacts with rails, investigating the role of intrinsic life-history traits and (2) investigate the drivers of contemporary vulnerability. During the most recent wave of extinction, we found that body size was an important correlate of rail extinctions, with both smaller and larger bodied species more likely to become extinct. Island endemism and small clutch size were the strongest predictors of contemporary vulnerability. Overall, island endemic rails tend to follow the same trajectory as extinct species, suffering mostly from invasive predators and overhunting, but with different traits targeted contemporarily compared to past extinctions. Moreover, modern anthropogenic threats have created the potential for new intricate pathways – or a contemporary ‘field of bullets’ – making future vulnerability potentially less predictable.

The “Critically Endangered” Alagoas Antwren Myrmotherula snowi is found only in the Atlantic Rainforest of north-east Brazil. We surveyed all sites where the species has been recorded, as well as 15 other potential sites. We summarise all observations of the species, focusing on the period from 2016 onwards, and including systematic censuses in three breeding seasons (October–March 2018/19, 2019/20, and 2020/21) at the type locality, Murici, where we also searched for nests of the species. We did not locate any individuals at sites other than Murici. The number of apparent individuals detected declined by 67% over seven years (a decline of 50% over the three years in which standardised systematic counts were made), and only six adults were observed in the most recent breeding season. The global population is now likely to be in single-digit figures. Of five nests found, four failed, through predation by snakes and opossums, and abandonment. We installed protective barriers to protect two of these nests from predators, which may have contributed to the single successful fledging. Such methods offer most hope for now of stalling the decline. Efforts to develop captive breeding methods with model species have been underway since 2019 but face many difficulties. Improving habitat protection and restoration is crucial but will only take effect in the long term.

Understanding the distribution and habitat requirements of species is crucial for designing conservation actions, yet this information is not available for many plant species. We report the first confirmed wild populations of Porroglossum parsonsii, which, because of its horticultural value, is commercialized in national and international markets, from where it was first described to science. Our large-scale survey of 341 10 × 30 m plots spanning Andean forests, paramo habitats and pasturelands in Colombia suggests that P. parsonsii has a restricted geographical distribution in Andean forests with high forest cover (71.4–86.2%), where it occurs in low numbers (5–17 individuals per plot). Because of its market value (USD 18–20 per plant) there is a risk the species could be collected illegally, and therefore the habitat of the species in the Santuario de Fauna y Flora de Iguaque requires appropriate conservation.

The family Syngnathidae contains 52 seahorse species, which inhabit a range of habitats including coral reefs, seagrass beds and coastal estuaries. The seahorse Hippocampus kelloggi is among the most widely distributed species, occurring from Indo-West Pacific to East Africa. This species was included in the IUCN Red List in 2017 and is classified as vulnerable according to A2cd criteria. In this study, three specimens collected from the central coast of Mozambique were investigated and based on morphology and mitochondrial subunit of cytochrome oxidase I (COI) were identified as H. kelloggi. These results confirmed for the first time the extensive range of occurrence of H. kelloggi on the central coast of Mozambique.

Spix’s Macaw Cyanopsitta spixii is one of the most endangered Neotropical Psittacidae species. Extinct in the wild in the year 2000, in June 2022 the first cohort of C. spixii was reintroduced to its original habitat. For a successful reintroduction of the species, it is necessary to examine the viability of the population against natural and external threats and the environmental requirements for success. Thus, this paper presents a “Population Viability Analysis” (PVA) for Spix’s Macaw. It used the Vortex and RangeShiftR software, biological and environmental data from a bibliographic survey, and information provided by the field team responsible for the reintroduction of the species, and who work directly with the species in captivity. We found that the minimum viable population (MVP) for reintroduction of the species is 20 individuals. However, considering the impact of disease, drought, hunting, and illegal trafficking, this population can only persist if the release of individuals from captivity occurs annually over the next 20 years combined with the reforestation of natural habitat to support population growth.