Goodness of Fit of Probability Distributions for Sightings as Species Approach Extinction

Estimating the probability that a species is extinct and the timing of extinctions is useful in biological fields ranging from paleoecology to conservation biology. Various statistical methods have been introduced to infer the time of extinction and extinction probability from a series of individual sightings. There is little evidence, however, as to which of these models provide adequate fit to actual sighting records. We use L-moment diagrams and probability plot correlation coefficient (PPCC) hypothesis tests to evaluate the goodness of fit of various probabilistic models to sighting data collected for a set of North American and Hawaiian bird populations that have either gone extinct, or are suspected of having gone extinct, during the past 150 years. For our data, the uniform, truncated exponential, and generalized Pareto models performed moderately well, but the Weibull model performed poorly. Of the acceptable models, the uniform distribution performed best based on PPCC goodness of fit comparisons and sequential Bonferroni-type tests. Further analyses using field significance tests suggest that although the uniform distribution is the best of those considered, additional work remains to evaluate the truncated exponential model more fully. The methods we present here provide a framework for evaluating subsequent models.     

Extinctions of vascular plants in Spain

The catalogue of extinct plants in Spain, comprising 27 taxa is updated. Included are four species not previously classified as extinct in Spain: Cyclamen purpurascens, Grammitis quaerenda, Stratiotes aloides and Vallisneria spiralis. We analyze the causes of extinction and explore the possible influence of botanical collections in species loss. The obtained data suggest that habitat loss has been the main cause of extinction and the impact of collecting is demonstrated to be irrelevant. We list the 21 species that have been designated as extinct in previous catalogues but which no longer have that status, 14 of them having been recovered thanks to botanical exploration and collection works.     

Trophically unique species are vulnerable to cascading extinction

Understanding which species might become extinct and the consequences of such loss is critical. One consequence is a cascade of further, secondary extinctions. While a significant amount is known about the types of communities and species that suffer secondary extinctions, little is known about the consequences of secondary extinctions for biodiversity. Here we examine the effect of these secondary extinctions on trophic diversity, the range of trophic roles played by the species in a community. Our analyses of natural and model food webs show that secondary extinctions cause loss of trophic diversity greater than that expected from chance, a result that is robust to variation in food web structure, distribution of interactions strengths, functional response, and adaptive foraging. Greater than expected loss of trophic diversity occurs because more trophically unique species are more vulnerable to secondary extinction. This is not a straightforward consequence of these species having few links with others but is a complex function of how direct and indirect interactions affect species persistence. A positive correlation between a species' extinction probability and the importance of its loss defines high-risk species and should make their conservation a priority.     

Drivers of extinction: the case of Azorean beetles

Oceanic islands host a disproportionately high fraction of endangered or recently extinct endemic species. We report on species extinctions among endemic Azorean beetles following 97% habitat loss since AD 1440. We infer extinctions from historical and contemporary records and examine the influence of three predictors: geographical range, habitat specialization and body size. Of 55 endemic beetle species investigated (out of 63), seven can be considered extinct. Single-island endemics (SIEs) were more prone to extinction than multi-island endemics. Within SIEs restricted to native habitat, larger species were more extinction-prone. We thus show a hierarchical path to extinction in Azorean beetles: species with small geographical range face extinction first, with the larger bodied ones being the most threatened. Our study provides a clear warning of the impact of habitat loss on island endemic biotas.     

BIODIVERSITY RESEARCH: When is a species really extinct? Testing extinction inference from a sighting record to inform conservation assessment

Aim The global extinction of a species typically represents the end point in a series of population extinctions, during which unique evolutionary history is lost at every stage. Insight into the process of extinction can provide the means to identify species at high risk, but the number of extinctions being identified languishes far behind true totals. More proactive ways of inferring extinction from limited data are required. Location Historic sightings, collections and specimen data from Australia and Asia. Method We used a technique called optimal linear estimation to analyse the sightings record of mammal and bird species of varying ecology, life history and population demography. The mammal species chosen were all considered regionally extinct in the literature, while the bird species chosen had all been highlighted as candidates for the new IUCN Red List category flag: Critically Endangered (Possibly Extinct). Results Nine of the ten mammal species were predicted to be probably extinct, but only two with 95% certainty. Seven of the ten bird species were predicted to be probably extinct, four with 95% certainty. Main conclusions Superficially, determining whether a species is extinct might seem a simple task, whereby we either find a species extant, or it is extinct. In reality, however, the task is much more complex. Techniques such as optimal linear estimation, in combination with other data sources, and knowledge of recording effort, may prove useful in inferring extinction across a variety of taxa but should not be used in isolation.     

Historical bird and terrestrial mammal extinction rates and causes

Aim Conservation of species is an ongoing concern. Location Worldwide. Methods We examined historical extinction rates for birds and mammals and contrasted island and continental extinctions. Australia was included as an island because of its isolation. Results Only six continental birds and three continental mammals were recorded in standard databases as going extinct since 1500 compared to 123 bird species and 58 mammal species on islands. Of the extinctions, 95% were on islands. On a per unit area basis, the extinction rate on islands was 177 times higher for mammals and 187 times higher for birds than on continents. The continental mammal extinction rate was between 0.89 and 7.4 times the background rate, whereas the island mammal extinction rate was between 82 and 702 times background. The continental bird extinction rate was between 0.69 and 5.9 times the background rate, whereas for islands it was between 98 and 844 times the background rate. Undocumented prehistoric extinctions, particularly on islands, amplify these trends. Island extinction rates are much higher than continental rates largely because of introductions of alien predators (including man) and diseases. Main conclusions Our analysis suggests that conservation strategies for birds and mammals on continents should not be based on island extinction rates and that on islands the key factor to enhance conservation is to alleviate pressures from uncontrolled hunting and predation.     

Examining the Extinction of the Barbary Lion and Its Implications for Felid Conservation

Estimations of species extinction dates are rarely definitive, yet declarations of extinction or extirpation are important as they define when conservation efforts may cease. Erroneous declarations of extinctions not only destabilize conservation efforts but also corrode local community support. Mismatches in perceptions by the scientific and local communities risk undermining sensitive, but important partnerships. We examine observations relating to the decline and extinction of Barbary lions in North Africa. Whilst the extinction predates the era of the scientific conservation movement, the decline is relatively well documented in historical records. Recently unearthed accounts suggest Barbary lions survived later than previously assumed. We use probabilistic methods to estimate a more recent extinction date for the subspecies. The evidence presented for a much later persistence of lions in North Africa, including generations when sightings were nil, suggests caution when considering felid populations as extinct in the wild. The case raises the possibility that captive animals descended from the Moroccan royal collection are closer contemporaries to wild Barbary lions. Furthermore, our results highlight the vulnerability of very small lion populations and the significance of continued conservation of remnant lion populations in Central and West Africa.     

Vascular plant extinctions in California: A critical assessment

Aim

Extinctions of species and subspecific taxa in hotspots of biodiversity deserve special attention. After more than 40 years of major efforts, estimates of extinct plant taxa in California seem to be somewhat stabilized. The time is ripe for an attempt to critically evaluate our current knowledge of plant extinctions in California and make a comparison with other countries with mediterranean‐type climates.

Location

California.

Methods

Besides species‐specific studies and personal communications, major databases and state floras were consulted.

Results

Compared with all numbers published earlier, the current analysis ended with smaller numbers of globally extinct plant species and taxa (13 and 17, respectively) and larger numbers of species and taxa extinct in California, but still present in at least one other state or country (15 and 15). For each species, life form, habitat, year of the last collection and assumed drivers of extinction are listed.

Main conclusions

Most of the presumed extinct taxa were originally present in one or two counties and often are known from only one or a very few collections. Therefore, the most robust generalization regarding factors contributing to taxon extinctions is a small range size and a low original abundance. Most of the presumed globally extinct taxa were originally present in lowlands where most of the human population and habitat destruction are concentrated. Taxa limited to special habitats, like wetlands, seem to be more predisposed to extinction. Among assumed drivers of plant extinction, agriculture, urbanization and development in general are the most often cited possibilities. Compared with other countries with mediterranean‐type climates, the extinction rate of vascular plants in California is lower than in Israel, comparable with the Cape Province of South Africa, Western Australia and continental Mediterranean European countries, and higher than in Chile.     

Predation selectively culls medium-sized species from island mammal faunas

Globally, elevated extinction risk in mammals is strongly associated with large body size. However, in regions where introduced predators exert strong top-down pressure on mammal populations, the selectivity of extinctions may be skewed towards species of intermediate body size, leading to a hump-shaped relationship between size and extinction risk. The existence of this kind of extinction pattern, and its link to predation, has been contentious and difficult to demonstrate. Here, we test the hypothesis of a hump-shaped body size–extinction relationship, using a database of 927 island mammal populations. We show that the size-selectivity of extinctions on many islands has exceeded that expected under null models. On islands with introduced predators, extinctions are biased towards intermediate body sizes, but this bias does not occur on islands without predators. Hence, on islands with a large-bodied mammal fauna, predators are selectively culling species from the lower end of the size distribution, and on islands with a small-bodied fauna they are culling species from the upper end. These findings suggest that it will be difficult to use predictable generalizations about extinction patterns, such as a positive body size–extinction risk association, to anticipate future species declines and plan conservation strategies accordingly.     

Orchid conservation in China from 2000 to 2020: Achievements and perspectives

We review achievements in the conservation of orchid diversity in China over the last 21 years. We provide updated information on orchid biodiversity and suggestions for orchid conservation in China. We outline national policies of biodiversity conservation, especially of orchid conservation, which provide general guidelines for orchid conservation in China. There are now approximately 1708 known species of Orchidaceae in 181 genera in China, including five new genera and 365 new species described over the last 21 years. The assessment of risk of extinction of all 1502 known native orchid species in China in 2013 indicated that 653 species were identified as threatened, 132 species were treated as data-deficient, and four species endemic to China were classified as extinct. Approximately 1100 species (ca. 65%) are protected in national nature reserves, and another ~66 species in provincial nature reserves. About 800 native orchid species have living collections in major botanical gardens. The pollination biology of 74 native orchid species and the genetic diversity and spatial genetic structure of 29 orchid species have been investigated at a local scale and/or across species distributions. The mycorrhizal fungal community composition has been investigated in many genera, such as Bletilla, Coelogyne, Cymbidium, Cypripedium, and Dendrobium. Approximately 292 species will be included in the list of national key protected wild plants this year. Two major tasks for near future include in situ conservation and monitoring population dynamics of endangered species.     

Reductions in connectivity and habitat quality drive local extinctions in a plant diversity hotspot

It is well documented that habitat loss is a major cause of biodiversity decline. However, the roles of the different aspects of habitat loss in local extinctions are less understood. Anthropogenic destruction of an area of habitat causes immediate local extinction but subsequently three additional gradual drivers influence the likelihood of delayed extinction: decreased habitat patch size, lower connectivity and habitat deterioration. We investigated the role of these drivers in local extinctions of 82 declining species in a UK biodiversity hotspot. We combined a unique set of ≈ 7000 vegetation surveys and habitat maps from the 1930s with contemporary species’ occurrences. We extrapolated from these surveys to the whole 2500‐km² study area using habitat suitability surfaces. The strengths of drivers in explaining local extinctions over this 70 yr period were determined by contrasting connectivity, patch size and habitat quality loss for locations at which a species went extinct and those with persisting occurrences. Species’ occurrences declined on average by 60%, with half of local extinctions attributable to immediate habitat loss and half to the gradual processes causing delayed extinctions. On average, locations where a species persisted had a 73% higher contemporary connectivity than those suffering extinctions, but showed no differences in historical connectivity. Furthermore, locations with extinctions experienced a 37% greater decline in suitability associated with changes in habitat type. The strength of the drivers and the proportion of extinctions depended on the species’ habitat specialism, but were affected only minimally by life‐history characteristics. In conclusion, we identified a hierarchy of drivers influencing local extinction: with connectivity loss being the strongest, suitability change being moderately important, but changes in habitat patch size having only weak effects. We suggest conservation efforts could be most effective by strengthening connectivity along with reducing habitat deterioration, which would benefit a wide range of species.     

Rediscovery of Leptoxis compacta (Anthony, 1854) (Gastropoda: Cerithioidea: Pleuroceridae)

The Mobile River Basin is a hotspot of molluscan endemism, but anthropogenic activities have caused at least 47 molluscan extinctions, 37 of which were gastropods, in the last century. Nine of these suspected extinctions were in the freshwater gastropod genus Leptoxis (Cerithioidea: Pleuroceridae). Leptoxis compacta, a Cahaba River endemic, has not been collected for >70 years and was formally declared extinct in 2000. Such gastropod extinctions underscore the imperilment of freshwater resources and the current biodiversity crisis in the Mobile River Basin. During a May 2011 gastropod survey of the Cahaba River in central Alabama, USA, L. compacta was rediscovered. The identification of snails collected was confirmed through conchological comparisons to the L. compacta lectotype, museum records, and radulae morphology of historically collected L. compacta. Through observations of L. compacta in captivity, we document for the first time that the species lays eggs in short, single lines. Leptoxis compacta is restricted to a single location in the Cahaba River, and is highly susceptible to a single catastrophic extinction event. As such, the species deserves immediate conservation attention. Artificial propagation and reintroduction of L. compacta into its native range may be a viable recovery strategy to prevent extinction from a single perturbation event.     

Keep collecting: accurate species distribution modelling requires more collections than previously thought

Aim Species distribution models (SDMs) use the locations of collection records to map the distributions of species, making them a powerful tool in conservation biology, ecology and biogeography. However, the accuracy of range predictions may be reduced by temporally autocorrelated biases in the data. We assess the accuracy of SDMs in predicting the ranges of tropical plant species on the basis of different sample sizes while incorporating real‐world collection patterns and biases. Location Tropical South American moist forests. Methods We use dated herbarium records to model the distributions of 65 Amazonian and Andean plant species. For each species, we use the first 25, 50, 100, 125 and 150 records collected and available for each species to analyse changes in spatial aggregation and climatic representativeness through time. We compare the accuracy of SDM range estimates produced using the time‐ordered data subsets to the accuracy of range estimates generated using the same number of collections but randomly subsampled from all available records. Results We find that collections become increasingly aggregated through time but that additional collecting sites are added resulting in progressively better representations of the species’ full climatic niches. The range predictions produced using time‐ordered data subsets are less accurate than predictions from random subsets of equal sample sizes. Range predictions produced using time‐ordered data subsets consistently underestimate the extent of ranges while no such tendency exists for range predictions produced using random data subsets. Main conclusions These results suggest that larger sample sizes are required to accurately map species ranges. Additional attention should be given to increasing the number of records available per species through continued collecting, better distributed collecting, and/or increasing access to existing collections. The fact that SDMs generally under‐predict the extent of species ranges means that extinction risks of species because of future habitat loss may be lower than previously estimated.     

国家濒危物种红色名录的生物多样性保护意义

IUCN濒危物种红色名录与国家濒危物种红色名录都是物种灭绝风险的测度, 前者是全球性评估, 后者则是国别研究。IUCN濒危物种红色名录预警了全球物种的濒危状况, 为全球生物多样性研究提供了大数据; 国别红色名录确定了各国物种受威胁状况, 填补了前者的知识空缺, 两份名录互为补充。目前对国家濒危物种红色名录重视不够。基于如下原因, 应当重视国别濒危物种红色名录的意义: (1)国家是濒危物种保护的行为主体, 物种在一个国家的生存状况是确定其保护级别、开展濒危物种保育的依据; (2)对于仅分布于一个国家的特有物种来说, 其国别濒危物种红色名录等级即是其全球濒危等级; (3)对于跨国境分布的物种来说, 国别濒危物种红色名录等级则确定了该物种在本国的生存状况; (4)结合IUCN濒危物种红色名录, 国别濒危物种红色名录为建立跨国保护地、保护迁徙物种的栖息地与跨国迁徙洄游通道提供依据; (5)国别濒危物种红色名录所特有的“区域灭绝”等级, 反映了一个物种边缘种群在该国的区域灭绝, 恢复“区域灭绝”物种是该物种原分布国重引入保育工作的重点; (6)国别濒危物种红色名录提供了该国物种编目、分类、分布和生存状况的最新信息。然而, 国别濒危物种红色名录的重要性在许多情况下被忽视了。目前正值全球新冠肺炎大流行, 人们正在重新审视人与野生动物的关系。我国将修订有关野生动物保护与防疫法法律以及《国家重点保护野生动物名录》, 防控新的人与野生动物共患疾病再次暴发。对于确定国家重点保护野生动物物种名录来言, 物种受威胁程度是物种列为国家重点保护物种的特征之一。重视国别红色名录有特别的意义。     

Evaluating the conservation status of epiphytic lichens of Italy: A red list

Despite the fact that Italy is among the lichenologically best known areas worldwide, a national red list of lichens is still lacking. The aim of this work was to provide a red list of the epiphytic lichens of Italy which could facilitate the inclusion of lichens in national conservation plans. The evaluation of the species against International Union for Conservation of Nature (IUCN) criteria was based on data from multiple sources which represent the best available information on the epiphytic lichens of Italy. The species were assigned to the IUCN categories mainly using criteria D and B. A total of 368 species were evaluated: for 23 species, information is missing from more than 50 years and they were listed as regionally extinct, 64 as critically endangered, 75 as endangered, 74 as vulnerable, 58 as near threatened, 20 as least concern and 54 species as data deficient. Our results indicate that more than one-fourth of the epiphytic lichens of Italy are likely to be threatened, so that further research and effort are needed to include lichens in the main national conservation plans. Our results also highlight the lack of information that still hampers the rigorous evaluation of Italian lichens against IUCN criteria.     

Ex situ conservation of plant diversity in Romania: A synthesis of threatened and endemic taxa

Romania hosts a relatively high species diversity, including 3,829 vascular and 979 non-vascular spontaneous plant taxa. Multiple national red lists exist, with the number of taxa assessed as threatened varying greatly between them, from 548 to 1,438, and with number of taxa assigned to a given threat category also varying between the different sources. A composite list including all taxa mentioned in at least one of the selected red listings from Romania is required in order to compensate for this lack of consensus and to assess their ex situ conservation status. In this study, we synthesized data from the national red lists and counted 1,220 spontaneous vascular plant species and 201 subspecies, of which 77 are endemic and 76 subendemic for Romania. In addition, 18 non-red-listed endemics and 14 subendemics have been added, bringing the total to 1,453 threatened and (sub)endemic plant taxa, representing almost 38% of the total native vascular flora of Romania. Despite the large network of protected areas in Romania, many taxa are still being threatened with extinction in the region mainly due to anthropogenic pressure. Several ex situ conservation measures have been employed to assure a more substantial buffer against plant extinction in the wild, supported by thorough and adequate conservation strategies and multiple means to reintroduce taxa back to their natural habitats. Consequently, our second aim was to evaluate the ex situ conservation status of these threatened and (sub)endemic plants from Romania, focussing on both conventional methods (cultivation in botanic gardens, seed banking) and biotechnological approaches (in vitro tissue culture, medium-term storage and cryostorage). Of the 1,453 taxa included in our list, 642 (44.2%) are conserved by ex situ approaches. Of these, 524 are harboured in the most important botanic gardens throughout Romania, while 156 are currently held in long-term seed banks locally or in the Millennium Seed Bank of the Royal Botanic Garden, Kew (UK). Conversely, only 64 taxa from the list are preserved at the national level through in vitro cultures, and cryopreservation protocols have been developed for only 8 taxa. Overall, more than half of the threatened and (sub)endemic vascular flora from Romania remains unprotected outside the classical in situ conservation measures. For red-listed bryophytes, only 0.6% are preserved in national ex situ collections. Moreover, some aspects related to population genetic studies and the genetic stability of ex situ conserved plants are also briefly discussed, as essential prerequisites for applied biodiversity conservation programs. Finally, considering the distribution range of targeted taxa, we included a synthesis of biotechnological approaches at both national and international level. Our study presents not only a first assessment of the ex situ conservation status of national red listed flora, but also, to our knowledge, the most comprehensive and updated overview of the rare, threatened and (sub)endemic taxa from Romania. This evaluation will provide a supporting tool for national decision- and policy-making actions for biodiversity conservation, using both in situ and ex situ approaches. We also highlight the need for an updated red list for the Romanian flora that accurately follows the IUCN assessment criteria and protocols.     

Reconstructing past species assemblages reveals the changing patterns and drivers of extinction through time

Predicting future species extinctions from patterns of past extinctions or current threat status relies on the assumption that the taxonomic and biological selectivity of extinction is consistent through time. If the driving forces of extinction change through time, this assumption may be unrealistic. Testing the consistency of extinction patterns between the past and the present has been difficult, because the phylogenetically explicit methods used to model present-day extinction risk typically cannot be applied to the data from the fossil record. However, the detailed historical and fossil records of the New Zealand avifauna provide a unique opportunity to reconstruct a complete, large faunal assemblage for different periods in the past. Using the first complete phylogeny of all known native New Zealand bird species, both extant and extinct, we show how the taxonomic and phylogenetic selectivity of extinction, and biological correlates of extinction, change from the pre-human period through Polynesian and European occupation, to the present. These changes can be explained both by changes in primary threatening processes, and by the operation of extinction filter effects. The variable patterns of extinction through time may confound attempts to identify risk factors that apply across time periods, and to infer future species declines from past extinction patterns and current threat status.     

Life-history characters and phylogeny are correlated with extinction risk in the Australian angiosperms

Aim To determine whether life‐history characters that affect population persistence (e.g. habit and life span) and those that influence reproductive success (e.g. sexual system and fruit type) are non‐randomly correlated with extinction risk (i.e. threat category) in the Australian flora (c. 19,000 species, of which c. 14% is threatened). To identify patterns that present useful conservation directions. To understand patterns of extinction risk in the Australian flora at a broad scale. Location Continental Australia. Methods A country‐wide exploration of four life‐history characters in the Australian flora (n = 18,822 species) was undertaken using reference texts, expert opinion, herbarium records and field work. For each character and threat‐category combination, a G‐test (using a log‐linear model) was performed to test the null hypothesis that the two factors were independent in their effects on count. A generalized linear model (GLM) with a logit link and binomial error distribution was constructed with the proportion of taxa in each extinction risk category as the response variable and the habit, sex and fruit‐type characters as explanatory terms. In a separate approach, we investigated patterns across the threat categories of non‐endangered extant, endangered, and extinct using a multinomial model. We examined whether or not species‐poor genera were more likely to contain threatened or extinct species than species‐rich genera. A GLM with a binomial error distribution and logit link function was constructed to obtain a weighted regression on the proportion of species listed as extinct or endangered within a genus versus the log of the size of the genus. We also used a supertree analysis and character tracing to investigate the role of phylogeny on extinction risk. Results We found that the Australian flora is primarily composed of bisexual shrubs with dry‐dehiscent fruits. Dioecious breeding systems (separate female and male flowers on separate plants) in many floras are the predominant unisexual system, but in Australia there are unexpectedly high levels of monoecy (separate female and male flowers on the same plant). Within the extinct data set of 31 species we detected a significant departure from that expected for habit but not for life span, sexual system or fruit type. There are significantly fewer trees on the extinct list than expected. This may reflect the greater resilience of trees than of other growth habits to extinction processes as well as the observation time‐frame. Within the endangered data set of 450 species we found significant differences in the representation of the observed characters from that expected within sex systems and fruit types. We show that, depending on the life form, unisexual breeding systems can be significantly and positively associated with endangered species compared with non‐threatened species. For example, there are more monoecious species than expected by chance among the tree species listed as endangered but fewer among the herbaceous life forms. Threat category was found to be non‐randomly clustered in some clades. Main conclusions Life‐history characters in certain combinations are predictive of extinction risk. Phylogeny is also an important component of extinction risk. We suggest that specific life‐history characters could be used for conservation planning and as an early warning sign for detecting vulnerability in lists of species.     

The role of a local rediscovery in the evaluation of the conservation status of a plant species: Testing the hypothesis of the biodiversity knowledge gap

Although habitat destruction and the introduction of exotic species are causing the extinction of many native species, the number of extinct species that are then rediscovered is surprising. However, before searching for meaning of rediscoveries, we should distinguish between a false and a true rediscovery to avoid the interpretation of changes in biodiversity knowledge as changes in the efforts to conserve biodiversity. Here, we proposed the hypothesis of the biodiversity knowledge gap and a conceptual scheme to test this hypothesis, discussing how to deal with the rediscovery of a putatively extinct species. In this paper, we dealt with the local rediscovery of the plant Neptunia pubescens Benth. (Fabaceae), hypothesizing that if its local rediscovery is a case of the biodiversity knowledge gap (false rediscovery), its conservation status will change. Furthermore, we provided taxonomic data, geographic coordinates and figures as support for its local rediscovery, as well as some considerations about the implications for the conservation of N. pubescens.     

Protocols for listing threatened species can forecast extinction

Risk‐ranking protocols are used widely to classify the conservation status of the world's species. Here we report on the first empirical assessment of their reliability by using a retrospective study of 18 pairs of bird and mammal species (one species extinct and the other extant) with eight different assessors. The performance of individual assessors varied substantially, but performance was improved by incorporating uncertainty in parameter estimates and consensus among the assessors. When this was done, the ranks from the protocols were consistent with the extinction outcome in 70–80% of pairs and there were mismatches in only 10–20% of cases. This performance was similar to the subjective judgements of the assessors after they had estimated the range and population parameters required by the protocols, and better than any single parameter. When used to inform subjective judgement, the protocols therefore offer a means of reducing unpredictable biases that may be associated with expert input and have the advantage of making the logic behind assessments explicit. We conclude that the protocols are useful for forecasting extinctions, although they are prone to some errors that have implications for conservation. Some level of error is to be expected, however, given the influence of chance on extinction. The performance of risk assessment protocols may be improved by providing training in the application of the protocols, incorporating uncertainty in parameter estimates and using consensus among multiple assessors, including some who are experts in the application of the protocols. Continued testing and refinement of the protocols may help to provide better absolute estimates of risk, particularly by re‐evaluating how the protocols accommodate missing data.