Ferula sinkiangensis K.M. Shen is a threatened medicinal plant endemic to Xinjiang, China, with a small population size and a narrow distribution range. We assessed the status of this species with respect to its population age structure, the level of threat and extinction risk. Only one population remains, in Yining County, Xinjiang. We conducted field surveys of the population in 2022 and 2023, counting 2,033 and 1,515 individuals, respectively, in 144 sample quadrats. We assessed the age structure of the population by counting the number of basal leaves of each individual. The frequency distribution had an inverted J-shape, indicative of a relatively stable age structure. However, the number of mature individuals was small, raising concerns about the risk of genetic drift and inbreeding. This species is also threatened by habitat destruction and inappropriate collection practices. We recommend that F. sinkiangensis is categorized as Critically Endangered on the IUCN Red List on the basis of criteria B2ab(iii), C2a(i) and D.

Two globally threatened tree species, the Critically Endangered Cola porphyrantha (Malvaceae) and the Endangered Gigasiphon macrosiphon (Fabaceae) are narrowly distributed in Kenya and Tanzania. In Tanzania, both species were first located in an isolated, unprotected forest fragment in the East Usambara Mountains in the early 2000s. As no assessment of these subpopulations had been made since then, we surveyed the forest fragment as well as nearby unprotected forest fragments. In contrast to the early 2000s when only five and two mature trees of C. porphyrantha and G. macrosiphon, respectively, were located, we found 18 and five mature trees of these species. We did not find either species in intensive surveys of seven neighbouring unprotected forest fragments but we located a single G. macrosiphon beside a river close to one of the unprotected fragments. Gigasiphon macrosiphon was also previously known from two sites in Amani Nature Reserve in the East Usambara Mountains, but recent surveys, including our own, failed to relocate these subpopulations. Because of heavy anthropogenic disturbance in the one site where the two species still occur and their general absence from adjacent forest, we are working with the local community to protect the isolated fragment. Additionally, in situ planting of locally grown seedlings of both species is being supported by Amani Nature Reserve.

The Jamaican flower bat Phyllonycteris aphylla is categorized as Critically Endangered on the IUCN Red List. It is endemic to Jamaica and formerly known only from Stony Hill Cave, where there are an estimated c. 500 individuals. Previously declared extinct twice, its rediscovery in 2010 at Stony Hill Cave marked new hope for the conservation of this important species. Although little is known about its ecology, the species is presumed to be a cave-obligate rooster and to rely exclusively on so-called hot caves, which are defined by high ambient temperatures and low air quality. In March–April 2023, we surveyed bats at seven caves throughout Jamaica. At two of these, Green Grotto Caves, St. Ann, and Rock Spring Caverns, St. Mary, we captured both male and pregnant female P. aphylla. At Green Grotto Caves, we captured 24 P. aphylla, and 66 at Rock Spring Caverns. We believe Rock Spring Caverns to be one of the largest known roosts of P. aphylla. Neither of these sites are hot caves as both are moderated by flowing water, although warmer chambers may be more important to this bat than to other species. Further monitoring of these populations and continued exploration of other potential roosts are vital for the protection of this species.

The Arabian leopard Panthera pardus nimr is categorized as Critically Endangered, with < 200 individuals estimated to remain in the wild. Historically the species ranged over an extensive area of western Saudi Arabia but, with no confirmed sightings since 2014, investigating potential continued presence and distribution is of critical conservation importance. We present the results of a comprehensive survey designed to detect any remaining Arabian leopard populations in Saudi Arabia. We conducted 14 surveys, deploying 586 camera-trap stations at 13 sites, totalling 82,075 trap-nights. Questionnaire surveys were conducted with 843 members of local communities across the Arabian leopard's historical range to assess the presence of leopards, other predators and prey species. Predator scats were collected ad hoc by field teams and we used mitochondrial DNA analysis to identify the originating species. We obtained 62,948 independent photographs of animals and people, but none were of Arabian leopards. Other carnivores appeared widespread and domestic animals were numerous, but wild prey were comparatively scarce. Three questionnaire respondents reported sightings of leopards within the previous year, but targeted camera-trap surveys in these areas did not yield evidence of leopards. Of the 143 scats sent for analysis, no DNA was conclusively identified as that of the leopard. From this extensive study, we conclude there are probably no surviving, sustainable populations of Arabian leopards in Saudi Arabia. Individual leopards might be present but were not confirmed. Any future Arabian leopard conservation in Saudi Arabia will probably require reintroduction of captive-bred leopards.

Conservation monitoring is paramount for the gathering of information on species and populations in need of conservation actions. However, monitoring of the mountain bongo Tragelaphus eurycerus isaaci, a Critically Endangered antelope endemic to Kenya, has hitherto been limited to surveillance (i.e. focused on persistence of the species in particular areas), thus limiting the information that could be retrieved on the status and trends of these populations. Using a newly developed identification system, we implemented robust design mark–recapture using existing camera-trap records of four wild subpopulations of the bongo. We provide data on sex and age structure and the first estimates of population size in the wild. Males and calves seem to be suffering higher mortality than females, and only two of the four monitored populations include adults of both sexes and calves. The combined size of these two breeding populations is estimated to be 29–50. Our findings confirm the critical situation of the mountain bongo in the wild and highlight the need for conservation actions to reinforce the wild populations for the long-term conservation of this antelope.

We present the results of two population surveys conducted 10 years apart (December 2010–February 2011 and December 2020–January 2021) of the Critically Endangered white-headed langur Trachypithecus leucocephalus in the Chongzuo White-Headed Langur National Nature Reserve, Guangxi Province, China. In the first survey, we recorded 818 individuals in 105 groups and 16 solitary adult males. In the second survey, we recorded 1,183 individuals in 128 groups and one solitary adult male. As a result of government policies, poaching for food and traditional medicine is no longer a primary threat to these langurs. However, severe forest loss and fragmentation caused by human activities could limit any future increase of this langur population.

The plant Carduncellus matritensis (Cardueae, Compositae) was formerly known from only a single locality: Cerro Negro in Madrid Province, Spain. It is one of the six endemic species of the Spanish flora considered to be extinct. The causes of its presumed extinction were anthropogenic: the growth of the city of Madrid subsumed the locality into the city, such that Cerro Negro is now a railway station. During 2021–2022 we discovered three new populations c. 50 km south of the type locality, with 130–166 mature individuals. Habitat fragmentation and degradation are the most significant threats facing the three populations. We categorize the conservation status of the species as Critically Endangered according to the IUCN Red List criteria. To avoid the loss of this species, we recommend both in situ (creation of micro-reserves) and ex situ (seed storage) conservation measures.

The rare plant Primula esquirolii, a karst cave species in the family Primulaceae, endemic to Guizhou, China, and with a presumed extremely small population, had not previously been observed since 1910. It is categorized as Endangered on the China Species Red List. In surveys during 2018–2022, we were unable to locate the species in its type location in Pingba county, but we discovered a previously unrecorded population of 44 mature individuals, 37 of which were long homostylous and seven of which were heterostylous. These individuals were discovered in Xiuwen county in February 2022, in an area of c. 50 m2, c. 40 km from the type location. All seven heterostylous individuals showed the short-styled morph. The almost homostylous P. esquirolii potentially faces the same high genetic load as other homostylous plants, and this may have led to its small population size and potential sensitivity to habitat destruction. Field surveys and informal interviews with local people indicated that the main threats to this species are its small population size and the loss of suitable habitat as a result of human activities. The most urgent requirement for the conservation of this species is to protect the habitat of this single known extant population and to carry out ex situ conservation. Further field surveys and research are also required to improve our understanding of the status of this species.

Fifty years of deforestation in the Arc of Deforestation have put at risk species survival, ecosystem services and the stability of biogeochemical cycles in Amazonia, with global repercussions. In response, we need to understand the diversity, distribution and abundance of flagship species groups, such as primates, which can serve as umbrella species for broad biodiversity conservation strategies and help mitigate climate change. Here we identify the range, suitable habitat areas and population size of Vieira's titi monkey Plecturocebus vieirai and use it as an emblematic example to discuss biodiversity conservation and climate change mitigation in one of the largest deforestation frontiers. Our findings show that deforestation for agriculture and cattle-ranching expansion is the major threat to P. vieirai and is responsible for present (56%) and projected (14%) reductions in habitat area and population size. We also found that human-driven climate change affects the P. vieirai niche negatively, triggering habitat degradation and further population decline even inside protected areas. Primate watching can be a profitable alternative to forest exploitation on private, public or Indigenous lands in the Arc of Deforestation and is a way to shift the traditional, predatory extraction of natural resources from Amazonia towards sustainable land use based on biodiversity conservation at local, regional and global scales, local people's welfare and climate change mitigation. New models of land use and income generation are required to protect the unique natural and human heritages of the Arc of Deforestation and the life-supporting ecosystem services and products provided by Amazonia.

With the advent of automated recording units, bioacoustic monitoring has become a popular tool for the collection of long-term data across extensive landscapes. Such methods involve two main components: hardware for audio data acquisition and software for analysis. In the acoustic monitoring of threatened species, a species-specific framework is often essential. Jerdon's courser Rhinoptilus bitorquatus is a Critically Endangered nocturnal bird endemic to a small region of the Eastern Ghats of India, last reported in 2008. Here we describe a reproducible and scalable acoustic detection framework for the species, comparing several commonly available hardware and detection methods and using existing software. We tested this protocol by collecting 24,349 h of data during 5 months. We analysed the data with two commercially available sound analysis programmes, following an analysis pipeline created for this species. Although we did not detect vocalizations of Jerdon's courser, this study provides a framework using a combination of hardware and software for future research that other conservation practitioners can implement. Vocal mimicry can aid or confound in detection and we highlight the potential role of mimicry in the detection of such threatened species. This species-specific acoustic detection framework can be scaled and tailored to monitor other species.

The Critically Endangered western long-beaked echidna Zaglossus bruijnii is believed to be distributed throughout the Vogelkop Peninsula in the Indonesian Province of West Papua, but there had formerly been no confirmed sightings of the species since the 1980s. We aimed to establish whether the species survives in this area. Fieldwork was carried out during January–April 2018 in Tambrauw Regency in the north and Teluk Bintuni Regency in the south. Fieldwork involved informal interviews with people, identified through chain referral sampling, who were knowledgeable about local animals and plants. Interviewees were asked about their knowledge of the western long-beaked echidna and if they had encountered them locally. Thirteen interviewees were familiar with the species and we were able to confirm informant records of one individual in Tambrauw Regency and three in Teluk Bintuni Regency. Measurements of the three individual echidnas in Teluk Bintuni Regency corroborated previous descriptions of the species. Interviewees described how echidnas are often seen in the forests around villages, especially during the wet season during January–April, when their foraging signs are easy to distinguish from those of other animals. These four records of the western long-beaked echidna are the first confirmed sightings since the 1980s. They suggest the species persists on the Vogelkop Peninsula, and anecdotal information from the interviewees suggests the species remains common. Nevertheless, detailed systematic surveys are required before any assertion about the status of this species can be made with confidence.

One of the three Critically Endangered and endemic primate species in Viet Nam, Delacour's langur Trachypithecus delacouri, is restricted to the north of the country. The largest remaining population is in Van Long Nature Reserve, Ninh Binh Province, and the second largest is in nearby Kim Bang Protection Forest, Ha Nam Province, with other populations believed to be too small for recovery. The population in Van Long has been well studied but the status of that of Kim Bang has not previously been adequately evaluated. To address this, a survey was conducted during 10 August–7 October 2018. In total, we recorded 13 groups comprising a total of at least 73 individuals, almost doubling the highest number reported in previous studies. We documented six new groups in Lien Son and Ba Sao communes in Kim Bang. Our findings indicate there is a high likelihood that Delacour's langur population in Kim Bang will recover and could be important for the long-term conservation of this Critically Endangered species. However, immediate and appropriate conservation measures need to be implemented to protect the population from major anthropogenic threats, namely poaching and habitat destruction, detected during our survey.

Rediscovery of living populations of a species that was presumed to be extirpated can generate new narratives for conservation in areas suffering from losses in biodiversity. We used field observations and DNA sequence data to verify the rediscovery of the Critically Endangered scincid lizard Emoia slevini on Dåno′, an islet off the coast of Guam in the southern Mariana Islands, where for > 20 years it had been considered possibly extirpated. Endemic to the Marianas, E. slevini has declined throughout its range and no longer occurs on as many as five islands from which it was historically known, most likely because of interactions with invasive species and loss of native forest. Our results show that individuals from Dåno′, the type locality for E. slevini, are genetically similar but not identical to E. slevini on Sarigan and Alamagan to the north, and that E. slevini is a close evolutionary relative to another congener in the southern Marianas that is currently recognized as Emoia atrocostata but probably represents an undescribed species in this archipelago. We also show that other, more broadly distributed species of Emoia occurring on Dåno′ are distant relatives to E. slevini and the Mariana lineage of E. atrocostata, providing further evidence of the distinctiveness of these taxa. The rediscovery of E. slevini on Dåno′ following rodent eradication and culling of a population of monitor lizards suggests that management of invasive species is key to the recovery of this skink in the Mariana Islands, and that a range eclipse on the larger neighbouring island of Guam best explains why the rediscovery took place at the periphery of the species’ historic range. A Chamorro abstract can be found in the supplementary material.

Vatica cauliflora P.S. Ashton (Dipterocarpaceae) is a threatened tree species endemic to Kapuas Hulu District, West Kalimantan Province, Indonesia. The species is only known from the type specimen collected in 1953. After this first collection, there was no record confirming the presence of this tree in its natural habitat. Our recent surveys in 2019 and 2020 located 179 individuals of the species in six unprotected locations. The population's size structure is dominated (62.6%) by young individuals within the 0–5 cm diameter class. Our surveys also showed that the habitat of V. cauliflora is degraded as a result of the negative effects of agriculture and logging. Assessment with the IUCN Red List criteria indicates that V. cauliflora should be categorized as Critically Endangered.

The Philippines is a global biodiversity hotspot, with a large number of threatened bird species, one of which is the ‘Critically Endangered’ Negros Bleeding-heart Gallicolumba keayi. The aim of this study was to investigate the habitat preference of the Negros Bleeding-heart and undertake species distribution modelling to locate areas of conservation importance based on identified suitable habitat. A survey of 94 point-counts was undertaken and eight camera traps were deployed from May to August 2018 in the Northwest Panay Peninsula Natural Park, Panay, Philippines. Habitat variables (canopy cover, understorey cover, ground cover, elevation, presence of rattan Calamus or Daemonorops spp. and pandan Pandanus sp., tree diameter at breast height, and branching architecture were measured in 5 m-radius quadrats. To identify areas of potentially suitable habitat for the Negros Bleeding-heart, species distribution was modelled in MaxEnt using tree cover and elevation data on Panay and Negros. Using a Generalised Linear Model, Negros Bleeding-heart presence was found to be significantly positively associated with dense understorey cover and dense canopy cover. Species distribution modelling showed that the Northwest Panay Peninsula Natural Park is currently the most suitably located protected area for Negros Bleeding-heart conservation, while protected areas in Negros require further law enforcement. It is imperative that protection is continued in the Northwest Panay Peninsula Natural Park, and more survey effort is needed to identify other critical Negros Bleeding-heart populations, around which deforestation and hunting ban enforcement is strongly recommended.

Coastal vegetation includes unique species with adaptations to the specific conditions of this environment, and in the Mediterranean region urban development of coastal areas has severely affected coastal ecosystems. Astragalus berytheus Boiss. & Blanche is a narrow endemic plant of the eastern Mediterranean coast, occurring in Lebanon and Palestine/Israel; its Red List status has not been previously assessed. As a result of the effects of urban sprawl in coastal areas A. berytheus is one of the most threatened plant taxa in Lebanon. We assess the conservation status of this taxon and propose conservation measures. Only one population of A. berytheus is extant in Lebanon, in the Tyre Coast Nature Reserve. We recommend that A. berytheus should be categorized as Endangered globally and as Critically Endangered at the national level in Lebanon. Unless adequate conservation measures are implemented A. berytheus is likely to go extinct in Lebanon in the near future.

A new species of Eriocaulon, E. vamanae, is described from the southern Western Ghats of Kerala, India. It resembles Eriocaulon nepalense var. luzulifolium (Mart.) Praj. & J.Parn. but differs in the shape of its involucral bracts and receptacle, the fusion of the sepals in male flowers, the shape and indumentum of the sepals in female flowers, the size and indumentum of the petals in female flowers, and the seed coat appendages. Eriocaulon vamanae is so far known only from the type locality, Meesapulimala in Idukki District, Kerala, and is assessed as ‘Critically Endangered’ according to the IUCN’s Red List Categories and Criteria.

Magnolia ovoidea is a narrowly endemic, Critically Endangered tree with a fragmented distribution in south-west Yunnan, China. We examined the size structure of this species, documented threats and assessed its extinction risk. We found the species in six locations, all in unprotected areas, in Maguan County. The largest subpopulations are in Donggua Lin and Youfang Po, with 17 and 50 living individuals, respectively. The distribution of the diameter at breast height of the M. ovoidea population has an inverse J-shape, indicating a stable size structure. However, the distribution of the height of seedlings is L-shaped, suggesting inhibited regeneration. The natural vegetation is severely fragmented in all six locations, surrounded by roads, farmlands, and Alnus nepalensis or Cunninghamia lanceolata plantations. We recommend that M. ovoidea should be categorized on the IUCN Red List as Critically Endangered based on criteria B2ab(iii) + C2a(i).

Assessments of extinction risk are required to inform conservation action, but the usefulness of assessments is undermined if they are not current. Ameerega planipaleae, a poison frog endemic to the cloud forests of central Peru, was last assessed in 2004. We therefore sought to provide updated data to inform the reassessment of this species. Based on our findings, we recommend that this frog remain categorized as Critically Endangered, but under modified criteria, and that conservation actions are taken to reduce the pressures of local threats, especially the overuse of agrochemicals.