Global Extinction Risk Research Articles

Behavioral Correlates of Primates Conservation Status: Intrinsic Vulnerability to Anthropogenic Threats.

Behavioral traits are likely to influence species vulnerability to anthropogenic threats and in consequence, their risk of extinction. Several studies have addressed this question and have highlighted a correlation between reproductive strategies and different viability proxies, such as introduction success and local extinction risk. Yet, very few studies have investigated the effective impact of social behaviour, and evidence regarding global extinction risk remains scant. Here we examined the effects of three main behavioral factors: the group size, the social and reproductive system, and the strength of sexual selection on global extinction risk. Using Primates as biological model, we performed comparative analysis on 93 species. The conservation status as described by the IUCN Red List was considered as a proxy for extinction risk. In addition, we added previously identified intrinsic factors of vulnerability to extinction, and a measure of the strength of the human impact for each species, described by the human footprint. Our analysis highlighted a significant effect of two of the three studied behavioral traits, group size and social and reproductive system. Extinction risk is negatively correlated with mean group size, which may be due to an Allee effect resulting from the difficulties for solitary and monogamous species to find a partner at low densities. Our results also indicate that species with a flexible mating system are less vulnerable. Taking into account these behavioral variables is thus of high importance when establishing conservation plans, particularly when assessing species relative vulnerability.

The trade in sharks and their products in the United Arab Emirates

The rapid growth in the demand for shark products, particularly fins, has led to the worldwide overexploitation of many elasmobranch species. Although there are growing concerns about this largely unregulated and unmonitored trade, little information still exists about its dynamics, the species involved and the impact of this pressure on stocks in various regions. Our study provides the first attempt at characterizing the trade in shark products from the United Arab Emirates (UAE), the fourth largest exporter in the world of raw dried shark fins to Hong Kong. A review of trade records and informal interviews with local traders confirmed that the UAE is being used as hub in the broader North Indian Ocean region for the trade in shark products with the Emirati fishery minimally contributing to this trade. Results based on morphological identification of sharks (n=12,069) and DNA barcoding of tissue samples (n=655) indicated that the trade was made up of at least 37 species. The most abundant families represented at the Dubai study site were the Sphyrnidae (9.3%), Lamnidae (9%) and Alopiidae (5.9%). While information was mostly limited to shark products originating from the UAE and Oman, results indicated that 45.3% of species traded were considered to be at high risk of global extinction based on the IUCN Red List Global Assessments. Since many of the species found during this survey are likely part of stocks shared with other countries, regional cooperation and management will be crucial to ensure their long term survival.

Double Jeopardy and Global Extinction Risk in Corals and Reef Fishes

Coral reefs are critically important ecosystems that support the food security and livelihoods of hundreds of millions of people in maritime tropical countries, yet they are increasingly threatened by overfishing, coastal pollution, climate change, and other anthropogenic impacts, leading to concerns that some species may be threatened with local or even global extinction. The concept of double jeopardy proposes that the risk of species extinction is elevated if species that are endemic (small range) are also scarce (low local abundance). Traditionally, marine macroecology has been founded on patterns of species richness and presence-absence data, which provide no information on species abundances or on the prevalence of double jeopardy. Here we quantify the abundances of >400 species of corals and fishes along one of the world's major marine biodiversity gradients, from the Coral Triangle hotspot to French Polynesia, a distance of approximately 10,000 km. In contrast to classical terrestrial studies, we find that the abundance of these species bears no relationship to the size of their geographic ranges. Consequently, double jeopardy is uncommon because endemics are often locally abundant, and conversely many pandemics are rare. The Coral Triangle hotspot has more numerically rare species (both endemic and pandemic) but also encompasses more species with intermediate and higher abundances. We conclude that conservation efforts in the sea should focus less on extinction risk and more on maintaining and rebuilding key ecological functions that are highly vulnerable to human pressures, even if species can avoid extinction.

Ghosts of the coast: global extinction risk and conservation of sawfishes

Abstract Sawfish are arguably the world's most imperilled marine fishes. All five species are classified as highly threatened with extinction: three are Critically Endangered (smalltooth sawfish Pristis pectinata, largetooth sawfish Pristis pristis, and green sawfish Pristis zijsron); two are Endangered (narrow sawfish Anoxypristis cuspidata, and dwarf sawfish Pristis clavata). Sawfishes are threatened primarily due to a combination of their low intrinsic rates of population increase, high catchability in fisheries, and high value. Sawfishes are among the world's largest marine fishes, and they are caught by a wide range of fishing gears owing to their tooth‐studded rostra being easily entangled. Sawfish fins are some of the most valuable for shark fin soup, and their rostra have long been traded as curios. In addition, they inhabit shallow coastal waters, estuaries, and rivers of the tropics and subtropics, down to a maximum depth rarely exceeding 100 m and are associated with threatened mangrove and seagrass habitats. Historically, sawfishes were distributed in the coastal waters of 90 countries and territories. Over the past century, their geographic distribution has been greatly diminished. For example, the smalltooth sawfish is now found in <20% of its former range. Globally, sawfishes are now entirely absent from 20 countries; 43 countries have lost at least one species. Sawfishes are legally protected, to some degree, in 16 of the 90 range states. These safeguards encompass, on average, 81% of their Extant distribution; however, the quality and breadth of protection varies dramatically across countries and species. Smalltooth sawfish currently has the least amount of such coverage of only half (49%) of Extant distribution. The global conservation strategy specifies actions to protect sawfish and their habitats. Such actions are urgently warranted to avoid global extinction and to restore robust populations for the benefit of coastal ecosystem function and biodiversity. © 2014 The Authors. Aquatic Conservation: Marine and Freshwater Ecosystems published by John Wiley & Sons, Ltd.

Accounting for observation reliability when inferring extinction based on sighting records

Given the current increase in global extinction risk of species, methods that are able to estimate the probability and the time of extinction based on a sighting record of a rare or poorly studied species are becoming increasingly important. One of the major obstacles when using such methods is that many sighting records are burdened with uncertain or controversial observations. What is accepted as a valid sighting can have a substantial effect on resulting predictions. Here we present a simple modification to an existing method that allows for the inclusion of specific sighting reliabilities of individual observations into predictions of the likelihood and the time of extinction. The approach is applied to the sighting records of four presumably extinct bird species. Results indicated that the Ivory-billed Woodpecker (Campephilus principalis) and the Eskimo Curlew (Numenius borealis) may be considered as extinct, even when recent controversial sightings are included in the analysis. The Nukupu`u (Hemignathus lucidus) and O`ahu `Alauahio (Paroreomyza maculata) could potentially still be extant, although with a low probability of persistence. The major advantage of the presented method is that, instead of applying some arbitrary threshold for the sighting reliability that is considered acceptable, it recognizes and incorporates the reliability of each observation into the resulting predictions, by estimating the most likely number of observations and the most likely time of the last observation. Its simplicity facilitates its application for assessments of a larger number species or populations, and makes it accessible as a decision tool.

A retrospective evaluation of the global decline of carnivores and ungulates.

Assessing temporal changes in species extinction risk is necessary for measuring conservation success or failure and for directing conservation resources toward species or regions that would benefit most. Yet, there is no long-term picture of genuine change that allows one to associate species extinction risk trends with drivers of change or conservation actions. Through a review of 40 years of IUCN-related literature sources on species conservation status (e.g., action plans, red-data books), we assigned retrospective red-list categories to the world's carnivores and ungulates (2 groups with relatively long generation times) to examine how their extinction risk has changed since the 1970s. We then aggregated species' categories to calculate a global trend in their extinction risk over time. A decline in the conservation status of carnivores and ungulates was underway 40 years ago and has since accelerated. One quarter of all species (n = 498) moved one or more categories closer to extinction globally, while almost half of the species moved closer to extinction in Southeast Asia. The conservation status of some species improved (toward less threatened categories), but for each species that improved in status 8 deteriorated. The status of large-bodied species, particularly those above 100 kg (including many iconic taxa), deteriorated significantly more than small-bodied species (below 10 kg). The trends we found are likely related to geopolitical events (such as the collapse of Soviet Union), international regulations (such as CITES), shifting cultural values, and natural resource exploitation (e.g., in Southeast Asia). Retrospective assessments of global species extinction risk reduce the risk of a shifting baseline syndrome, which can affect decisions on the desirable conservation status of species. Such assessments can help conservationists identify which conservation policies and strategies are or are not helping safeguard biodiversity and thus can improve future strategies.

Extinction risk and conservation of the world’s sharks and rays

The rapid expansion of human activities threatens ocean-wide biodiversity. Numerous marine animal populations have declined, yet it remains unclear whether these trends are symptomatic of a chronic accumulation of global marine extinction risk. We present the first systematic analysis of threat for a globally distributed lineage of 1,041 chondrichthyan fishes-sharks, rays, and chimaeras. We estimate that one-quarter are threatened according to IUCN Red List criteria due to overfishing (targeted and incidental). Large-bodied, shallow-water species are at greatest risk and five out of the seven most threatened families are rays. Overall chondrichthyan extinction risk is substantially higher than for most other vertebrates, and only one-third of species are considered safe. Population depletion has occurred throughout the world's ice-free waters, but is particularly prevalent in the Indo-Pacific Biodiversity Triangle and Mediterranean Sea. Improved management of fisheries and trade is urgently needed to avoid extinctions and promote population recovery. DOI: http://dx.doi.org/10.7554/eLife.00590.001.

Areal sizes of high, intermediate, low and total suitable habitats are correlated to the global extinction risk for mammals

The relationships between areal sizes of high, intermediate, low, and total sum of habitats with low, intermediate and high suitability habitat ranges, and the International Union for Conservation of Nature (IUCN) threatened status of global terrestrial mammals were studied. Polyserial correlation analysis showed that all types of areal size closely and positively correlated with IUCN categories of threatened species. The results indicate that area-based extinction risk assessment is feasible and reliable in species? conservation prioritization. Furthermore, the partial polyserial correlation test indicates that significant correlations between the IUCN threatened status of species and range sizes of high, intermediate and low suitability habitats are not influenced by the polyserial correlation between IUCN threatened status and total suitability habitat range size. Thus, the prediction of species? extinction risks can be accurately fulfilled by evaluating the areal size of any one of total, high, intermediate or low suitability ranges. The present study implies that if the area size information of a totally suitable range is not available for species? extinction risk assessment, the usage of areal sizes from any parts of suitable habitats (high, intermediate or low) are effective surrogates.

A clarification of Gnetum L. (Gnetaceae) in Africa and the description of two new species

Gnetum L. is a genus of economic importance distributed in the humid rainforests of Central Africa. The African species of Gnetum are dioecious climbers and only two species (Gnetum africanum Welw. and G. buchholzianum Engl.) have been described previously. The names G. africanum and G. buchholzianum have been applied interchangeably to similar morphological forms of Gnetum specimens in Africa or on duplicates of specimens causing taxonomic confusion. The nomenclature of Gnetum species in Africa is thus in need of reappraisal. Morphological descriptions are based on examination of over 300 specimens from various herbaria, mainly B, BR, FHI, J, K, LISC, P, PRE, WAG and YA. The original applications of the names Gnetum africanum and Gnetum buchholzianum are clarified and two new African species (Gnetum interruptum E.H. Biye sp. nov. and Gnetum latispicum E.H. Biye sp. nov.) are described on the basis of morphological features. A key to the African species is provided and the main characters, such as the shape and size of spike that are essential in the recognition of species in the genus Gnetum in Africa as well as the importance of conservation are discussed. These species are assessed as threatened and at a high risk of global extinction according to the IUCN Red List categories and criteria, and are in need of conservation measures for their protection.

Update or Outdate: Long‐Term Viability of the IUCN Red List

AbstractIt is estimated that the global yearly expenditure on biodiversity conservation action exceeds one billion U.S. dollars. One of the key tools for prioritizing conservation actions is the International Union for Conservation of Nature (IUCN) Red List, the most authoritative and comprehensive source of information on the global extinction risk of species (covering ca. 60,000 as of today). While IUCN's vision is to increase the taxonomic coverage of the Red List, no adequate plan exists to keep it up to date. As species assessments become outdated after 10 years under IUCN rules, our simulations reveal that with the limited budget currently available for reassessment, most of the Red Listing effort may be wasted soon. Indeed, 17% of the species’ assessments are already outdated. To minimize the budget needed to keep assessments up to date in the Red List, we propose a mixed strategy of online reassessments and budget growth. We show that largely replacing workshops with online consultations is a more sustainable strategy that would save U.S. $2.8 million per year (35% of the budget). Sharing the cost of such a strategy among Organization for Economic Co‐operation and Development (OECD) countries (U.S. $156,000 per country per year) would ensure that the multimillion dollar spending based on the Red List remains effective in the long term.

The Likelihood of Extinction of Iconic and Dominant Herbivores and Detritivores of Coral Reefs: The Parrotfishes and Surgeonfishes

Parrotfishes and surgeonfishes perform important functional roles in the dynamics of coral reef systems. This is a consequence of their varied feeding behaviors ranging from targeted consumption of living plant material (primarily surgeonfishes) to feeding on detrital aggregates that are either scraped from the reef surface or excavated from the deeper reef substratum (primarily parrotfishes). Increased fishing pressure and widespread habitat destruction have led to population declines for several species of these two groups. Species-specific data on global distribution, population status, life history characteristics, and major threats were compiled for each of the 179 known species of parrotfishes and surgeonfishes to determine the likelihood of extinction of each species under the Categories and Criteria of the IUCN Red List of Threatened Species. Due in part to the extensive distributions of most species and the life history traits exhibited in these two families, only three (1.7%) of the species are listed at an elevated risk of global extinction. The majority of the parrotfishes and surgeonfishes (86%) are listed as Least Concern, 10% are listed as Data Deficient and 1% are listed as Near Threatened. The risk of localized extinction, however, is higher in some areas, particularly in the Coral Triangle region. The relatively low proportion of species globally listed in threatened Categories is highly encouraging, and some conservation successes are attributed to concentrated conservation efforts. However, with the growing realization of man's profound impact on the planet, conservation actions such as improved marine reserve networks, more stringent fishing regulations, and continued monitoring of the population status at the species and community levels are imperative for the prevention of species loss in these groups of important and iconic coral reef fishes.

A novel approach for global mammal extinction risk reduction

AbstractWith one‐fourth of the world's mammals threatened with extinction and limited budget to save them, adopting an efficient conservation strategy is crucial. Previous approaches to setting global conservation priorities have assumed all species to have equal conservation value, or have focused on species with high extinction risk, species that may be hard to save. Here, we identify priority species for optimizing the reduction in overall extinction risk of the world's threatened terrestrial mammals. We take a novel approach and focus on species having the greatest recovery opportunity using a new conservation benefit metric: the Extinction risk Reduction Opportunity (ERO). We discover that 65–87% of all threatened and potentially recoverable species are overlooked by existing prioritization approaches. We use the ERO metric to prioritize threatened species, but the potential applications are broader; ERO has the potential to integrate with every strategy that aims to maximize the likelihood of conservation success.

Hosts of the Plio-Pleistocene past reflect modern-day coral vulnerability.

The risk of global extinction of reef-building coral species is increasing. We evaluated extinction risk using a biological trait-based resiliency index that was compared with Caribbean extinction during the Plio-Pleistocene, and with extinction risk determined by the International Union for Conservation of Nature (IUCN). Through the Plio-Pleistocene, the Caribbean supported more diverse coral assemblages than today and shared considerable overlap with contemporary Indo-Pacific reefs. A clear association was found between extant Plio-Pleistocene coral genera and our positive resilience scores. Regional extinction in the past and vulnerability in the present suggests that Pocillopora, Stylophora and foliose Pavona are among the most susceptible taxa to local and regional isolation. These same taxa were among the most abundant corals in the Caribbean Pliocene. Therefore, a widespread distribution did not equate with immunity to regional extinction. The strong relationship between past and present vulnerability suggests that regional extinction events are trait-based and not merely random episodes. We found several inconsistencies between our data and the IUCN scores, which suggest a need to critically re-examine what constitutes coral vulnerability.

Global Conservation Priorities for Marine Turtles

Where conservation resources are limited and conservation targets are diverse, robust yet flexible priority-setting frameworks are vital. Priority-setting is especially important for geographically widespread species with distinct populations subject to multiple threats that operate on different spatial and temporal scales. Marine turtles are widely distributed and exhibit intra-specific variations in population sizes and trends, as well as reproduction and morphology. However, current global extinction risk assessment frameworks do not assess conservation status of spatially and biologically distinct marine turtle Regional Management Units (RMUs), and thus do not capture variations in population trends, impacts of threats, or necessary conservation actions across individual populations. To address this issue, we developed a new assessment framework that allowed us to evaluate, compare and organize marine turtle RMUs according to status and threats criteria. Because conservation priorities can vary widely (i.e. from avoiding imminent extinction to maintaining long-term monitoring efforts) we developed a “conservation priorities portfolio” system using categories of paired risk and threats scores for all RMUs (n = 58). We performed these assessments and rankings globally, by species, by ocean basin, and by recognized geopolitical bodies to identify patterns in risk, threats, and data gaps at different scales. This process resulted in characterization of risk and threats to all marine turtle RMUs, including identification of the world's 11 most endangered marine turtle RMUs based on highest risk and threats scores. This system also highlighted important gaps in available information that is crucial for accurate conservation assessments. Overall, this priority-setting framework can provide guidance for research and conservation priorities at multiple relevant scales, and should serve as a model for conservation status assessments and priority-setting for widespread, long-lived taxa.

Rarity and extinction risk in coral reef angelfishes on isolated islands: interrelationships among abundance, geographic range size and specialisation

Determining the species most vulnerable to increasing degradation of coral reef habitats requires identification of the ecological traits that increase extinction risk. In the terrestrial environment, endemic species often face a high risk of extinction because of an association among three traits that threaten species persistence: small geographic range size, low abundance and ecological specialisation. To test whether these traits are associated in coral reef fishes, this study compared abundance and specialisation in endemic and widespread angelfishes at the remote Christmas and Cocos Islands in the Indian Ocean. The interrelationships among traits conferring high extinction risk in terrestrial communities did not apply to these fishes. Endemic angelfishes were 50–80 times more abundant than widespread species at these islands. Furthermore, there was no relationship between abundance and ecological specialisation. Endemic species were not more specialised than widespread congeners and endemics used similar resources to many widespread species. Three widespread species exhibited low abundance and some degree of specialisation, which may expose them to a greater risk of local extinction. For endemic species, high abundance and lack of specialisation on susceptible habitats may compensate for the global extinction risk posed by having extremely small geographic ranges. However, recent extinctions of small range reef fishes confirm that endemics are not immune to the increasing severity of large-scale disturbances that can affect species throughout their geographic range.

Micropropagation and conservation of endangered species Plantago algarbiensis and P. almogravensis

Plantago algarbiensis and P. almogravensis are endemic Al tolerant species from the Western-centre of the Algarve region (South of Portugal) and Portuguese Southwest coast, respectively, which are in risk of global extinction. The aim of this work was to establish an efficient protocol to in vitro propagate these species using shoots obtained from in vitro germinated seeds. The best results in terms of multiplication response were afforded in Murashige and Skoog's (MS) medium supplemented with 6-benzyladenine (8.5 and 9.2 shoots per explant in P. algarbiensis and P. almogravensis, respectively). Shoots of both species showed a great rooting capacity (100 and 80 % for P. algarbiensis and P. almogravensis, respectively) that was not significantly influenced by the concentration of MS macronutrients or auxins. Plants were acclimatized to ex vitro conditions, exhibited normal development (survival rate of 95 and 80 % in P. algarbiensis and P. almogravensis, respectively), and were successfully reintroduced in their natural habitat.

Translocations: Providing Outcomes for Wildlife, Resource Managers, Scientists, and the Human Community

Abstract The World Conservation Union (1987) defines a translocation as a release of animals with the intention of establishing, reestablishing, or augmenting an existing population. Despite frequent use as a tool for the management of threatened and endangered wildlife, the full benefits of translocations often go unrealized. In this article, I demonstrate how translocations can achieve outputs for conservation management, conservation science, and the wider human community, using North Island (NI) Saddleback or Tieke (Philesturnus rufusater) as an illustrative example. From a conservation management perspective, NI Saddleback have been salvaged from a relic population of less than 500 birds on 484‐ha Hen Island to a metapopulation of approximately 6,000 birds on 13 offshore islands and at two mainland New Zealand sites. These translocations have reduced the risk of global extinction for this species and helped restore the ecosystems involved. All these translocations have occurred in the past 42 years from known source populations and with known numbers of birds released. The resulting replicated serial population bottlenecks provide numerous scientific opportunities for conservation and biological research. Although the first Saddleback translocations were to reserves closed to the public, subsequent translocations have been to open reserves, providing the wider human community with an opportunity to see and be actively involved in the management of a threatened endemic species. This has raised the profile of both NI Saddleback and other species and has provided wider community conservation benefits. These three outputs illustrate the value of translocations for resource management and conservation science and for increasing community interest, participation, and investment in biological conservation.

Small fish, big fish, red fish, blue fish: size‐biased extinction risk of the world's freshwater and marine fishes

ABSTRACTAim In light of the current biodiversity crisis, there is a need to identify and protect species at greatest risk of extinction. Ecological theory and global‐scale analyses of bird and mammal faunas suggest that small‐bodied species are less vulnerable to extinction, yet this hypothesis remains untested for the largest group of vertebrates, fish. Here, we compare body‐size distributions of freshwater and marine fishes under different levels of global extinction risk (i.e. listed as vulnerable, endangered or critically endangered according to the IUCN Red List of Threatened Species) from different major sources of threat (habitat loss/degradation, human harvesting, invasive species and pollution).Location Global, freshwater and marine.Methods We collated maximum body length data for 22,800 freshwater and marine fishes and compared body‐size frequency distributions after controlling for phylogeny.Results We found that large‐bodied marine fishes are under greater threat of global extinction, whereas both small‐ and large‐bodied freshwater species are more likely to be at risk. Our results support the notion that commercial fishing activities disproportionately threaten large‐bodied marine and freshwater species, whereas habitat degradation and loss threaten smaller‐bodied marine fishes.Main conclusions Our study provides compelling evidence that global fish extinction risk does not universally scale with body size. Given the central role of body size for trophic position and the functioning of food webs, human activities may have strikingly different effects on community organization and food web structure in freshwater and marine systems.

RANGE-RESTRICTED, SPECIALIST BORNEAN BUTTERFLIES ARE LESS LIKELY TO RECOVER FROM ENSO-INDUCED DISTURBANCE

The forest fires induced by the El Niño Southern Oscillation (ENSO) in 1997-1998 resulted in the temporary extirpation of more than 100 lowland butterfly species at a forest site in Borneo. Species with more restricted ranges were less likely to recover over the following four years. Matched-pair analyses revealed that species with lower initial abundances, restricted geographic ranges, and more specialized larvae were less likely to return. Specialization differed predictably between the (more generalist) wide-range and (more specialized) restricted-range species in our data set, and both geographic range and level of specialization were important in multivariate models. These are the first observations directly linking extent of occurrence, ecological specialization, and observed recovery following local extirpation. If recovery time exceeds the frequency of disturbance, local extirpation can lead to local extinction. Given that ENSO-induced disturbances are increasing in frequency, in severity, and in geographic scale, these results suggest that specialist species with restricted geographic ranges could be at particularly high risk of global extinction.

Minimum viable population sizes and global extinction risk are unrelated

Theoretical and empirical work has shown that once reduced in size and geographical range, species face a considerably elevated risk of extinction. We predict minimum viable population sizes (MVP) for 1198 species based on long-term time-series data and model-averaged population dynamics simulations. The median MVP estimate was 1377 individuals (90% probability of persistence over 100 years) but the overall distribution was wide and strongly positively skewed. Factors commonly cited as correlating with extinction risk failed to predict MVP but were able to predict successfully the probability of World Conservation Union Listing. MVPs were most strongly related to local environmental variation rather than a species' intrinsic ecological and life history attributes. Further, the large variation in MVP across species is unrelated to (or at least dwarfed by) the anthropogenic threats that drive the global biodiversity crisis by causing once-abundant species to decline.