Extinctions are occurring at an unprecedented rate as a consequence of human activities. Vertebrates constitute the best-known group of animals, and thus the group for which there are more accurate estimates of extinctions. Among them, freshwater fishes are particularly threatened and many species are declining. Here we report the extinction of an endemic freshwater fish of Mexico, the Catarina pupfish Megupsilon aporus, the sole species of the genus Megupsilon. We present a synopsis of the discovery and description of the species, the threats to, and degradation of, its habitat, and the efforts to maintain the species in captivity before it became extinct in 2014. The loss of the Catarina pupfish has evolutionary and ecological implications, and highlights the crisis of freshwater fish extinctions. It is a warning of the likely fate of more than 200 freshwater fish species threatened with extinction in Mexico. To save these species, the country urgently needs a national strategy to articulate a bold conservation effort, with better policies on ecosystem management and water use.

Many species are poorly known, with the sum of our knowledge represented by specimens in museums. For assessment of conservation status the most enigmatic and challenging species are probably those known only from a single specimen. We examine the potential persistence of such species using the orchid flora of Madagascar as a case study. We apply a statistical method that tests the likelihood of species presence in relation to the time when a species was collected and a measure of annual collection effort, calculated in three ways based on specimen collection over time. The results suggest that as of 2000 up to nine of the 236 orchid species known from a single specimen may be inferred to be extinct under at least one of the three methods of estimating collection effort and extinction. In addition, up to two additional species are likely to be extinct by 2018 assuming no new collections were made by that time. Substantial collection effort and/or additional evidence will be needed to reach a decision on the persistence of more recently observed species known only from a single collection. This represents a challenge for conservation practitioners.

Extinction is a profound biological event, yet despite its finality it can be difficult to verify and many frameworks have been proposed to define formally that extinction has occurred. For most taxonomic groups and regions there is no reliable list of species considered to be probably or possibly extinct. The record of plant extinctions in Australia is no exception, characterized by high turn-over within lists, low transparency of attribution and lack of consistency between jurisdictions. This makes it impossible to evaluate how many plant taxa have become extinct in Australia. We present an ecological framework for assessing the likelihood of plant extinctions, based on taxonomic soundness, degree of habitat modification, detectability and search effort, underpinned by the best available expert knowledge. We show that, in sharp contrast to both the fate of the Australian fauna and prevailing assumptions, only 12 of 71 plant taxa currently listed as or assumed to be extinct are considered probably extinct, and a further 21 possibly extinct. Twenty taxa listed as or assumed to be extinct have dubious taxonomy or occurrence in Australia, and the remaining 18 taxa are considered possibly extant and further surveys are required to ascertain their status. The list of probably and possibly extinct plants is dwarfed by the number thought extinct but rediscovered since 1980. Our method can be used for vascular floras in other regions characterized by well-documented and curated floras and high levels of expert knowledge, and provides a transparent platform for assessing changes in the status of biodiversity.

The Annamite mountains of Viet Nam and the Lao People's Democratic Republic (Lao) are an area of exceptional mammalian endemism but intensive poaching has defaunated much of the region, creating an extinction crisis for the endemic species. To make efficient use of limited conservation resources, it is imperative that conservation stakeholders obtain basic information about poorly known and threatened endemics. We present the first comprehensive information on the ecology, distribution and status of the little-known endemic Annamite striped rabbit Nesolagus timminsi. We used a systematic camera-trapping design to study the species in five areas in Viet Nam and Lao. In 29,180 camera-trap-nights we recorded 152 independent events at 36 of 266 stations. We obtained an additional 143 independent detections across 12 stations from a supplementary non-systematic survey. We analysed activity patterns and social behaviour. We also used single-species occupancy models to assess factors that influence occupancy at the landscape scale. We used N-mixture models to obtain local abundance estimates in one target area. The Annamite striped rabbit was found to be nocturnal and primarily solitary. Species occupancy was best explained by a proxy for past hunting pressure, with no significant relationships to current anthropogenic or environmental factors. Local abundance was 0.57 individuals per camera-trap station for one of our sites, and estimated to be zero at the other site where hunting appears to have been more intense. Our results provide information on priority areas for targeted anti-poaching efforts and give the first conservation baseline for the species.

The illegal wildlife trade is driving declines in populations of a number of large, charismatic animal species but also many lesser known and restricted-range species, some of which are now facing extinction as a result. The ploughshare tortoise Astrochelys yniphora, endemic to the Baly Bay National Park of north-western Madagascar, is affected by poaching for the international illegal pet trade. To quantify this, we estimated population trends during 2006–2015, using distance sampling surveys along line transects, and recorded national and international confiscations of trafficked tortoises for 2002–2016. The results suggest the ploughshare tortoise population declined > 50% during this period, to c. 500 adults and subadults in 2014–2015. Prior to 2006 very few tortoises were seized either in Madagascar or internationally but confiscations increased sharply from 2010. Since 2015 poaching has intensified, with field reports suggesting that two of the four subpopulations are extinct, leaving an unknown but almost certainly perilously low number of adult tortoises in the wild. This study has produced the first reliable population estimate of the ploughshare tortoise and shows that the species has declined rapidly because of poaching for the international pet trade. There is an urgent need for increased action both in Madagascar and along international trade routes if the extinction of the ploughshare tortoise in the wild is to be prevented.

The assessment of the conservation status of a species is the first step in developing a conservation strategy. IUCN Red Lists assessments are an important starting point for conservation actions and the most commonly applied method for assessing the extinction risk of a species. In this study, the global conservation status of the rock rose Helianthemum caput-felis Boiss. (Cistaceae), a perennial Mediterranean plant, was evaluated using the Red List criteria. The distribution of the species was determined by monitoring historical localities and all other suitable sites along the western Mediterranean coasts for 6 years. For each confirmed locality, the ecological and population parameters and the main threats were recorded; these data were used in a quantitative analysis of the species' extinction risk. Our findings indicate there have been several recent extinctions, and there is a continuing decline in the species' area of occurrence, habitat quality and number of reproductive plants. The main threats are related to human activities. Extinction models indicate a probability of quasi-extinction risk of c. 30% in five generations or c. 45% in three generations, with the species likely to become extinct in seven currently known localities within the next 10 years. Application of the Red List criteria indicates H. caput-felis should be categorized as Endangered. This study confirms that legal protection and passive conservation measures are insufficient to guarantee the persistence of a plant species. Active conservation and management actions are needed to protect this and other threatened species of the Mediterranean Basin.

Release methods can influence the outcome of reintroductions. We tested the effect of delayed, immediate and supplementary food/shelter release treatments on the reintroduction of brushtail possums Trichosurus vulpecula to an environment in which introduced predators, particularly foxes, were subject to control. Monitoring of 48 radio-collared possums over 3 months revealed that immediate release possums settled into a stable range significantly faster than other groups, but there were no differences in survival, dispersal distance, reproduction or body condition. Ten days after release possums from all treatment groups had lost body mass, but by day 60 most were heavier than at the time of translocation. After release, possums sometimes used shelter sites easily accessible to predators, but within 3 weeks they regularly selected safer shelter. Risky shelter selection and loss of condition immediately after release suggests that supplementary food and shelter could be beneficial, but supportive measures were rarely used or did not have the desired effect. In an environment with higher predator densities, risky shelter selection could lead to high post-release predation, and mass loss could encourage animals to forage in riskier ways, further increasing vulnerability. In these environments effective uptake of supplementary food and shelter could reduce predation risk, but supplementary measures would need to be presented in a way that maximises uptake. In contrast, if post-release predation risk is low then supportive measures may not be required. Innovative methods for providing post-release support should continue to be developed for reintroductions to areas where supportive measures are needed.

The conservation benefits of maintaining social groupings during and after animal translocations are unclear. Although some studies report improved post-release survival, others found no discernible influence on reintroduction success. Understanding the effects of social groupings is difficult because release methods can influence the animals’ ability to maintain social groups. We explored this relationship by first studying whether release protocols influenced post-release cohesion in the communal burrowing bettong Bettongia lesueur, and then investigating whether maintenance of social cohesion conferred any post-release advantage. We released bettongs into a small (8 ha) and large (2,600 ha) area and compared the proportion that maintained social groupings in the different settings. The proportion of bettongs sharing with previous warren co-occupants was higher than expected by chance in both areas, however, a significantly higher proportion of bettongs maintained social groupings in the small (75%) compared to the large release area (13%). This suggests bettongs prefer to maintain social groupings but are unable to locate members of their group in large release areas. Bettongs that did maintain social groupings showed no difference in reproductive or health outcomes compared to those that formed new social groupings, suggesting no benefit to reintroduction success. We conclude that release protocols can influence post-release cohesion, but that greater cohesion does not necessarily confer advantages to group-living animals. To test the importance of social cohesion, further research on reintroductions should compare post-release parameters for animals released using protocols that do and do not facilitate maintenance of social groupings.

Post-translocation monitoring is fundamental for assessing translocation success and identifying potential threats. We measured outcomes for four cohorts of tuatara Sphenodon punctatus translocated to warmer climates outside of their ecological region, to understand effects of climate warming. Translocation sites were on average 2–4 °C warmer than the source site. We used three short-term measures of success: survival, growth and reproduction. Data on recaptures, morphometric measurements, and reproduction were gathered over 2.5 years following release. Although decades of monitoring will be required to determine long-term translocation success in this species, we provide an interim measure of population progress and translocation site suitability. We found favourable recapture numbers, growth of founders and evidence of reproduction at most sites, with greater increases in body mass observed at warmer, less densely populated sites. Variable growth in the adult population at one translocation site suggested that higher population density, intraspecific competition, and lower water availability could be responsible for substantial weight loss in multiple individuals, and we make management recommendations to reduce population density. Overall, we found that sites with warmer climates and lower population densities were potentially beneficial to translocated tuatara, probably because of enhanced temperature-dependent and density-dependent growth rates. We conclude that tuatara could benefit from translocations to warmer sites in the short term, but further monitoring of this long-lived species is required to determine longer-term population viability following translocation. Future vulnerability to rising air temperatures, associated water availability, and community and ecosystem changes beyond the scope of this study must be considered.

The conservation of threatened species requires information on how management activities influence habitat quality. The Critically Endangered black rhinoceros Diceros bicornis is restricted to savannahs representing c. 5% of its historical range. Fire is used extensively in savannahs but little is known about how rhinos respond to burning. Our aim was to understand rhino responses to fire by studying habitat selection and foraging at multiple scales. We used resource selection functions and locations of 31 rhinos during 2014–2016 to study rhino habitat use in Serengeti National Park, Tanzania. Rhino selectivity was quantified by comparing forage consumption to plant species availability in randomly sampled vegetation plots; rhino diets were subsequently verified through DNA metabarcoding analysis of faecal samples. Rhino habitat use was a unimodal function of fire history, with highly occupied sites having fire frequencies of < 0.6 fires/year and maximum occupancy occurring at a fire frequency of 0.1 fires/year. Foraging stations had characteristic plant communities, with 17 species associated with rhino foraging. Rhinos were associated with, and disproportionately consumed, woody plants, forbs and legumes, all of which decreased in abundance with increasing fire frequency. In contrast to common management practices, multiple lines of evidence suggest that the current fire regime in the Serengeti negatively influences rhino habitat use and foraging and that frequent fire limits access of rhinos to preferred forage. We outline a conceptual model to guide managers and conservationists in the use of fire under variable habitat conditions.

South Africa's private sector is vital to rhino conservation yet there is a lack of research into the attitudes of current and potential rhino owners towards rhino conservation and horn trade. We surveyed 169 members of the South African private wildlife ranching industry to examine these matters. We sought to understand: (1) ranchers’ motivations for owning or not owning rhinos, (2) how rhino ownership affects ranchers’ income and operations, and (3) the attitudes of wildlife industry members towards legalization of global rhino horn trade. Our findings indicate that all respondents recognize the risks of rhino ownership and tend to distrust national and provincial environmental departments. In addition to these concerns, rhino owners have substantial monthly security and management expenditures. We found positive attitudes overall towards global rhino horn trade. Rhino owners strongly agreed that legalization would benefit rhino owners and rhino conservation. Documenting the realities of private rhino ownership and the opinions of the wildlife industry is important for policy design and for informed debate about the legalization of the rhino horn trade.

Legalized trade in commercially farmed wildlife products is sometimes promoted as a conservation strategy. In theory, flooding the market with cheaper or better quality products will decrease the profitability of poaching. Bear bile is highly sought-after for use in traditional medicine and overhunting to supply the demand for bear parts has led to declining populations across South-east Asia. Bear bile farming was established to help supply the high demand for bear bile. In Viet Nam it is legal to keep registered bears, but illegal to extract or sell bear bile. We conducted semi-structured interviews with 66 bear bile farmers in Viet Nam to examine the conservation implications of bear bile farming. The results show that demand for wild bear bile was not satisfied by the widespread availability of farmed bear bile. Farmers report a strong consumer preference and willingness to pay more for wild-sourced products. The existence of bear bile farms presents considerable challenges to law enforcement. The results suggest that bear bile farming in Viet Nam relies on restocking from wild populations, and farmers openly admit to extracting and selling bear bile, in clear violation of national legislation. The case of bear bile farming in Viet Nam provides an example of wildlife farming failing to reduce pressure on a once widely distributed and relatively abundant species. Research into consumer values, attitudes and behaviours will help to improve understanding of market drivers and help inform the design of effective species conservation and management strategies.

Throughout the tropics, hunting and fishing are critical livelihood activities for many Indigenous peoples. However, these practices may not be sustainable following recent socio-economic changes in Indigenous populations. To understand how human population growth and increased market integration affect hunting and fishing patterns, we conducted semi-structured interviews in five Kukama-Kukamilla communities living along the boundary of the Pacaya-Samiria National Reserve, in the Peruvian Amazon. Extrapolated annual harvest rates of fish and game species by these communities amounted to 1,740 t and 4,275 individuals (67 t), respectively. At least 23 fish and 27 game species were harvested. We found a positive correlation between village size and annual community-level harvest rates of fish and a negative relationship between market exposure and mean per-capita harvest rates of fish. Catch-per-unit-effort (CPUE) analyses indicated local depletion of fish populations around larger, more commercial communities. Catch-per-unit-effort of fish was lower in more commercial communities and fishers from the largest village travelled further into the Reserve, where CPUE was higher. We found no effect of village size or market exposure on harvest rates or CPUE of game species. However, larger, more commercial communities targeted larger, economically valuable species. This study provides evidence that human population growth and market-driven hunting and fishing pose a growing threat to wildlife and Indigenous livelihoods through increased harvest rates and selective harvesting of species vulnerable to exploitation.

Tourists approaching wild animals can potentially cause disturbance as a result of the perceived predation risk. Risk effects arise when prey alter their behaviour in response to predators. This response may carry costs through its impact on fitness-related activities such as foraging. We recorded behavioural responses of whale sharks Rhincodon typus to experimental vessel and swimmer approaches. We simulated the disturbance caused by ecotourism in the foraging site of this planktivorous fish in Bahia de Los Angeles, Gulf of Baja California, Mexico. Stress-related behaviours (vigilance, change of direction, diving and acceleration) were more common directly after both types of disturbance than before, in particular after approach by a swimmer. Individuals were more likely to be vigilant when they were new to the bay, but we did not find evidence of within-season behavioural habituation. Sharks were 24% more likely to forage before human stimuli than after. Our study highlights negative effects of vessel and swimmer approaches on whale shark behaviour, with a short-term increase in stress-related behaviours potentially carrying energetic costs, combined with a decrease in food intake following the disturbance. Our results indicate concerns about the impact of ecotourism on large fish species. An important next step would be to determine whether these short-term behavioural responses to the perception of predation risk negatively affect fitness. Among other guidelines, we recommend preventing swimmers from approaching if whale sharks stop feeding when a vessel approaches.