Extinction Risk Of Species Research Articles

Impacts of bycatch from beach seining: a case study of a shrimp fishery in Brazil.

It is commonly assumed that beach seining (BS) is more sustainable than bottom trawling because it involves non-motorized operations and limited fishing power. However, no scientific evidence supports this assumption. To address this gap, we evaluated the impact of beach seining, taking a small-scale shrimp fishery in northeast Brazil. Data collected monthly from December 2016 to November 2017 and in literature, were assessed (BS 31,001 individuals, 119 species, 37 families, and 19 orders; BT 6,031 individuals, 58 species, 20 families, and 14 orders). Beach seining demonstrated a lower proportion of bycatch (BS 1:2.3; BT 1:3.2), higher total shrimp catch (BS 87.2 t; BT 65 t), and greater species diversity than bottom trawling catches (BS 119; BT 58). Other aspects were closer associated with bottom trawling, such as the composition of dominant families (Sciaenidae and Pristigasteridae), the proportion of rare species (BS 30%; BT 24%) juveniles (BS 11g; BT 13g), the risk of species extinction, and the composition of ecological guilds. Despite their social significance, both fishing gears showed similar ecological indicators and adverse effects. The findings establish that the ecological concerns related to the impact of bottom trawling are also applicable to beach seine.

Determining the generation length and level of morphological and genetic differentiation in the Data Deficient glossy grass skink (Pseudemoia rawlinsoni)

Context Human activities are having a significant impact on biodiversity worldwide, to the extent that we are in the midst of the sixth mass extinction event. Although a substantial proportion of species globally have an elevated risk of extinction, some species are poorly known and there is insufficient information available to adequately assess their risk of extinction. Aims and methods One such species is the glossy grass skink (Pseudemoia rawlinsoni), a widespread but enigmatic lizard species in south-eastern Australia. In order to improve our knowledge of its life history, and particularly its generation length, we examined museum specimens collected from across the range of the species, supplemented with measurements from field-caught individuals. Key results We estimated that the species reaches sexual maturity in 3 years, at approximately 40 mm snout–vent length. Its generation length was estimated as 5 years. Sexual dimorphism was evident, and female body size was positively related to litter size. Although there was no evidence for substantial variation in morphology across the range of the glossy grass skink, a phylogeographic analysis using mitochondrial DNA sequence data (ND4) revealed the presence of seven genetic sublineages (up to 5.1% genetic divergence) within the species. Conclusions The glossy grass skink appears to be a single, but widespread and genetically variable, species. Implications Our study demonstrates how a targeted, multifaceted study can be effective at rapidly gathering data that can be used to contribute vital information to the assessment of extinction risk in Data Deficient species.

Modelling the probability of meeting IUCN Red List criteria to support reassessments.

Comparative extinction risk analysis-which predicts species extinction risk from correlation with traits or geographical characteristics-has gained research attention as a promising tool to support extinction risk assessment in the IUCN Red List of Threatened Species. However, its uptake has been very limited so far, possibly because existing models only predict a species' Red List category, without indicating which Red List criteria may be triggered. This prevents such approaches to be integrated into Red List assessments. We overcome this implementation gap by developing models that predict the probability of species meeting individual Red List criteria. Using data on the world's birds, we evaluated the predictive performance of our criterion-specific models and compared it with the typical criterion-blind modelling approach. We compiled data on biological traits (e.g. range size, clutch size) and external drivers (e.g. change in canopy cover) often associated with extinction risk. For each specific criterion, we modelled the relationship between extinction risk predictors and species' Red List category under that criterion using ordinal regression models. We found criterion-specific models were better at identifying threatened species compared to a criterion-blind model (higher sensitivity), but less good at identifying not threatened species (lower specificity). As expected, different covariates were important for predicting extinction risk under different criteria. Change in annual temperature was important for criteria related to population trends, while high forest dependency was important for criteria related to restricted area of occupancy or small population size. Our criteria-specific method can support Red List assessors by producing outputs that identify species likely to meet specific criteria, and which are the most important predictors. These species can then be prioritised for re-evaluation. We expect this new approach to increase the uptake of extinction risk models in Red List assessments, bridging a long-standing research-implementation gap.

Spatial patterns and predictors of seed plants' extinction risks in Asian countries

Asian countries are experiencing severe biodiversity loss, so it is crucial to develop practical conservation actions and strategies. Threats to species are often dynamic, as their impacts on extinction risk change over time. There is an urgent need to better understand how these factors are interrelated and how they vary spatially with extinction risk. Here, we presented a spatially explicit method to evaluate the dynamic trends and predictors of seed plants' extinction risks across countries, using National Red List data from China, Japan, and Sri Lanka as case studies, by calculating the Red List Index (RLI) and mapping the percentage of seed plants facing increasing risks and pressures. We found overall decrease in extinction risks, however, a substantial number of species, ranging from 328 to 1343 depending on the country, still showed increasing extinction risks. Increasing extinction risks of plants was strongly correlated with changes in threats, such as urban expansion, temperature changes, and tree canopy cover changes, rather than static threat intensity. Specifically, increasing tree canopy cover significantly associated with plant extinction risks in both China and Sri Lanka, where large-scale afforestation and economic forest plantation probably resulted in habitat degradation and species loss. Concerningly, our findings indicated that land-use change was the dominant driver of increased species extinction risk in these two countries, in contrast to climate change in Japan. As governments commit to the Kunming-Montreal Global Biodiversity Framework, we suggest them to make site-specific or taxa-specific policies to ensure the effectively prevention of biodiversity loss.

Threats to aquatic biodiversity and possible management strategies in Lake Victoria

AbstractLake Victoria is the second‐largest freshwater lake in the world, with a surface area of 68,800 km2. The lake is rich in natural resources that are essential to the local economy and livelihoods. However, International Union for Conservation of Nature (IUCN) ranks 76% of freshwater species endemic to the Lake Victoria Basin as threatened with extinction. The biodiversity richness of the lake is still diminishing, and the risk of species extinction is increasing. Many species are yet to be identified, and thus the number of species threatened with extinction exceeds what is currently known. Furthermore, the lake is home to species that are found nowhere else on the planet, but its protection is never given the attention it needs. Genetic diversity loss is harmful to future populations and influences sustainability of the ecosystem. The decline in Lake Victoria's biodiversity is primarily attributed to various pressing issues, including water pollution, invasive species, climate change, overexploitation and the challenges stemming from high human population density. These problems are exacerbated by inadequate regulatory enforcement and a lack of comprehensive data and information to inform and guide conservation efforts. If these factors are not addressed, they may have a detrimental impact on Lake Biodiversity. This article aims to document the main threats to aquatic biodiversity as well as potential management strategies for preventing further losses of the aquatic biodiversity in Lake Victoria. The study recommends reviewing, bolstering and reinforcing the rules and regulations governing the extraction, accessibility and discharge of nutrients into the lake. The national governments should work with local governments, non‐governmental organizations and local people to safeguard and conserve the lake's biodiversity. The national governments of the riparian nations should also reserve funds each fiscal year specifically for research that would inform effective management measures to prevent further losses of the lake's biodiversity.

Using SMS surveys to understand songbird ownership and shark product consumption in Indonesia

Abstract The unsustainable use of wildlife increases the risk of species extinction. In biodiversity-rich Indonesia, information on the scale of wildlife use is limited and requires further study. To address this, we explored the potential of text messaging (short message service; SMS) surveys to investigate levels and spatial patterns of domestic wildlife use, using songbird keeping and shark consumption as case studies because of their widespread occurrence in all 34 Indonesian provinces. We sent 340,000 messages for each survey during October–November 2018 and incentivized responses with a mobile data package as reward. We obtained survey response rates of 1.4% (songbird ownership) and 1.5% (shark consumption). Our results revealed an estimated 175.7 million songbirds being kept by 35% (80.4–86.6 million) of the Indonesian population and 33.5 million people (14% of the Indonesian population) to have consumed shark products in their lifetime. We identified hotspots of songbird ownership in several provinces in Java, corroborating previous findings, and new ones in the North Sumatra province, for example. The provinces of Maluku, Aceh and East Nusa Tenggara had the highest numbers of reported shark consumers per 1,000 people. Responses indicated a wide variety of shark products being consumed, highlighting the need for in-depth research to understand the explanatory factors behind these practices. These findings demonstrate the potential of SMS surveys to be a cost-effective approach for conducting large-scale studies on wildlife consumption patterns over a short period of time.

Centralized red muscle in Odontaspis ferox and the prevalence of regional endothermy in sharks.

The order Lamniformes contains charismatic species such as the white shark Carcharodon carcharias and extinct megatooth shark Otodus megalodon, and is of particular interest given their influence on marine ecosystems, and because some members exhibit regional endothermy. However, there remains significant debate surrounding the prevalence and evolutionary origin of regional endothermy in the order, and therefore the development of phenomena such as gigantism and filter-feeding in sharks generally. Here we show a basal lamniform shark, the smalltooth sand tiger shark Odontaspis ferox, has centralized skeletal red muscle and a thick compact-walled ventricle; anatomical features generally consistent with regionally endothermy. This result, together with the recent discovery of probable red muscle endothermy in filter feeding basking sharks Cetorhinus maximus, suggests that this thermophysiology is more prevalent in the Lamniformes than previously thought, which in turn has implications for understanding the evolution of regional endothermy, gigantism, and extinction risk of warm-bodied shark species both past and present.

Uncovering antagonisms in recovery planning for species at risk: A diagnostic approach

AbstractAmid Earth's ongoing sixth mass extinction event, numerous measures have been proposed to recover the populations of species at risk of extinction. However, the methods and objectives of different species' recovery plans sometimes conflict with each other, causing a conundrum we refer to as recovery–action antagonism. Recovery–action antagonism reduces the cost‐effectiveness of conservation programs and can increase the extinction risk of nontarget species. We describe a method to identify interactions between recovery actions, including antagonisms proposed for different at‐risk species in a given location. The method includes a process to evaluate potential drivers of recovery‐action antagonism and other interaction types using principal coordinates analysis and distance‐based redundancy analysis. We illustrate various applications of the method through case studies performed in Pelee Island and Rouge National Urban Park, two biodiverse areas in Ontario, Canada. Potential antagonism was identified between 1.5% (Pelee) and 5% (Rouge) of the evaluated recovery actions. Although the rate of antagonism was low in our case studies, the method allows the identification of a variety of interactions, which can help to prioritize similar and complementary actions that will benefit a large number of species while minimizing actions that may have competing outcomes.

Tradeoffs between resources and risks shape the responses of a large carnivore to human disturbance

Wide-ranging carnivores experience tradeoffs between dynamic resource availabilities and heterogeneous risks from humans, with consequences for their ecological function and conservation outcomes. Yet, research investigating these tradeoffs across large carnivore distributions is rare. We assessed how resource availability and anthropogenic risks influence the strength of lion (Panthera leo) responses to disturbance using data from 31 sites across lions’ contemporary range. Lions avoided human disturbance at over two-thirds of sites, though their responses varied depending on site-level characteristics. Lions were more likely to exploit human-dominated landscapes where resources were limited, indicating that resource limitation can outweigh anthropogenic risks and might exacerbate human-carnivore conflict. Lions also avoided human impacts by increasing their nocturnal activity more often at sites with higher production of cattle. The combined effects of expanding human impacts and environmental change threaten to simultaneously downgrade the ecological function of carnivores and intensify human-carnivore conflicts, escalating extinction risks for many species.

Ongoing declines for the world’s amphibians in the face of emerging threats

Systematic assessments of species extinction risk at regular intervals are necessary for informing conservation action1,2. Ongoing developments in taxonomy, threatening processes and research further underscore the need for reassessment3,4. Here we report the findings of the second Global Amphibian Assessment, evaluating 8,011 species for the International Union for Conservation of Nature Red List of Threatened Species. We find that amphibians are the most threatened vertebrate class (40.7% of species are globally threatened). The updated Red List Index shows that the status of amphibians is deteriorating globally, particularly for salamanders and in the Neotropics. Disease and habitat loss drove 91% of status deteriorations between 1980 and 2004. Ongoing and projected climate change effects are now of increasing concern, driving 39% of status deteriorations since 2004, followed by habitat loss (37%). Although signs of species recoveries incentivize immediate conservation action, scaled-up investment is urgently needed to reverse the current trends.

The (integrative) taxonomy driving conservation of cryptic species: an example of Neotropical Myotis

It is estimated that less than 25% of the eukaryotic species on Earth have been formally described. On the other hand, we are going through a biodiversity crisis that has caused mass species extinctions, many of which have not yet been discovered by science. This puts taxonomy at the forefront of the biological sciences. Based on a case study on neotropical Myotis, a hyper-diverse and cryptic bat genus, we argue that (integrative) taxonomy plays a leading role in generating knowledge that can aid the assessment of the extinction risk of species and, consequently, guide conservation strategies. Moreover, the identification of complexes of cryptic taxa employs integrative taxonomic methods that are often based on genetic and morphological evidence, generating basic information on the demographic history, occupation of habitats, and distributional limits of taxa that are generally rare or endemic.

A further new species of Isoglossa (Acanthaceae) from the Eastern Arc Mountains of Tanzania

SummaryIsoglossa pareensis I.Darbysh. & Hemp (Acanthaceae), from submontane moist forest at Mwala in the South Pare Mountains of northeastern Tanzania, is described and illustrated. This species is considered to be related to I. gregorii (S.Moore) Lindau and I. punctata (Vahl) Brummitt & J.R.I.Wood, which are widespread in the montane forests of eastern Africa, but it clearly differs from these species in inflorescence structure and indumentum and in anther morphology. Notes on the habitat requirements and extinction risk of this new species are provided; it is considered to be Vulnerable under IUCN criterion D2 because of its extremely limited range and a plausible future threat from wildfires. The recent discovery of the Critically Endangered acanthaceous herb Asystasia masaiensis Lindau at lower, drier elevations at the same site is also reported and the first known photograph of that species is reproduced

Incorporating global change reveals extinction risk beyond the current Red List

Global changes over the past few decades have caused species distribution shifts and triggered population declines and local extinctions of many species. The International Union for Conservation of Nature (IUCN) Red List of Threatened Species (Red List) is regarded as the most comprehensive tool for assessing species extinction risk and has been used at regional, national, and global scales. However, most Red Lists rely on the past and current status of species populations and distributions but do not adequately reflect the risks induced by future global changes. Using distribution maps of >4,000 endemic woody species in China, combined with ensembled species distribution models, we assessed the species threat levels under future climate and land-cover changes using the projected changes in species' suitable habitats and compared our updated Red List with China's existing Red List. We discover an increased number of threatened species in the updated Red List and increased threat levels of >50% of the existing threatened species compared with the existing one. Over 50% of the newly identified threatened species are not adequately covered by protected areas. The Yunnan-Guizhou Plateau, rather than the Hengduan Mountains, is the distribution center of threatened species on the updated Red Lists, as opposed to the threatened species on the existing Red List. Our findings suggest that using Red Lists without considering the impacts of future global changes will underestimate the extinction risks and lead to a biased estimate of conservation priorities, potentially limiting the ability to meet the Kunming-Montreal global conservation targets.

Human-modified landscapes driving the global primate extinction crisis.

The world's primates have been severely impacted in diverse and profound ways by anthropogenic pressures. Here, we evaluate the impact of various infrastructures and human-modified landscapes on spatial patterns of primate species richness, at both global and regional scales. We overlaid the International Union for the Conservation of Nature (IUCN) range maps of 520 primate species and applied a global 100 km2 grid. We used structural equation modeling and simultaneous autoregressive models to evaluate direct and indirect effects of six human-altered landscapes variables (i.e., human footprint [HFP], croplands [CROP], road density [ROAD], pasture lands [PAST], protected areas [PAs], and Indigenous Peoples' lands [IPLs]) on global primate species richness, threatened and non-threatened species, as well as on species with decreasing and non-decreasing populations. Two-thirds of all primate species are classified as threatened (i.e., Critically Endangered, Endangered, and Vulnerable), with ~86% experiencing population declines, and ~84% impacted by domestic or international trade. We found that the expansion of PAST, HFP, CROP, and road infrastructure had the most direct negative effects on primate richness. In contrast, forested habitat within IPLs and PAs was positively associated in safeguarding primate species diversity globally, with an even stronger effect at the regional level. Our results show that IPLs and PAs play a critical role in primate species conservation, helping to prevent their extinction; in contrast, HFP growth and expansion has a dramatically negative effect on primate species worldwide. Our findings support predictions that the continued negative impact of anthropogenic pressures on natural habitats may lead to a significant decline in global primate species richness, and likely, species extirpations. We advocate for stronger national and international policy frameworks promoting alternative/sustainable livelihoods and reducing persistent anthropogenic pressures to help mitigate the extinction risk of the world's primate species.

Addressing data-deficiency of threatened sharks and rays in a highly dynamic coastal ecosystem using environmental DNA

Marine biodiversity loss is accelerating, leading to the elevated extinction risks of many species, including sharks and rays. To mitigate these losses, information on their distribution and community composition is needed. Monitoring these (often) mobile species is challenging, especially in remote, highly dynamic and turbid coastal areas. Here, we use an environmental DNA (eDNA) approach to: (1) establish the presence and distribution of elasmobranch species, (2) compare this to a conventional fisheries-dependent approach, and (3) determine the influence of season, area-based protection and habitat on elasmobranch community composition in the highly dynamic Bijagós Archipelago in Guinea-Bissau (West Africa). We collected 127 seawater samples and detected elasmobranch DNA in 58 (45.7%) of these samples, confirming the presence of 13 different elasmobranch species (2 sharks, 11 rays), including seven threatened species. Eight of the species detected by the eDNA-approach were also recorded in a fisheries observer program, which recorded another eight species not detected by the eDNA approach. The most commonly occurring species, based on the number of eDNA sampling locations were the pearl whipray (Fontitrygon margaritella), smalltooth stingray (Hypanus rudis), scalloped hammerhead shark (Sphyrna lewini), and the blackchin guitarfish (Glaucostegus cemiculus). Species composition and richness differed significantly before (January-March) and after the rainy season (November-December). Furthermore, we showed that community composition and species richness did not differ between protected (MPA) and non-protected areas of the archipelago. Thus, we confirm that eDNA approaches are a valuable and non-invasive tool to study threatened shark and ray species in data-deficient and dynamic coastal areas, especially when combined with conventional monitoring methods such as fisheries-dependent information.

Assessing the extinction risks of amphibians impacted by infectious diseases

Emerging infectious diseases (EIDs) are a major threat to amphibians worldwide. Determining the extinction risk of species susceptible to EIDs is challenging because of data limitations, especially in the initial stages of emergence and spread of disease. The fast rate of spread of many EIDs makes it necessary to assess the extinction risk of impacted host species before detailed mechanistic (epidemiological) or correlative (ecological niche) models can be developed. We present a simple method for identifying species that are at the highest risk of extinction due to an EID. Our method incorporates projections of the spatial spread of disease into IUCN Red List assessments under criteria A3 (based on future population reductions), D2 (plausible future threats), and E (probability of extinction). We apply this method to assess the extinction risk of salamander species in Europe susceptible to population declines caused by Batrachochytrium salamandrivorans (Bsal), the agent of the salamander plague. Our results indicate a high risk of extinction for European salamanders as a result of the spreading Bsal infection. Depending on the rate of spread from the current Bsal localities, and the emergence of new localities through human travel and transport, the number of species threatened by Bsal can range from a few to almost 30 of the 40 species that occur in Europe. Our method allows preliminary assessments of extinction risk based on limited information. For species at risk of extinction due to fast-spreading EIDs, it provides a pragmatic and precautionary solution until more realistic models can be developed.

First demographic insights reveal high extinction risk of an endemic raptor species: the Reunion harrier

Gathering demographic information on rare species is critical to understanding their population dynamics and implementing efficient conservation measures. Using integrated models, we jointly analyzed multiple data sets, including capture–recapture, GPS tracking and nest monitoring data collected over the last 10 years, to provide the first demographic insights for one of the world's rarest raptors, the endemic Reunion harrier Circus maillardi. We estimated key demographic rates including annual survival and breeding parameters (clutch size, hatching and fledging success), and used population projection models to assess population growth rate and quasi‐extinction risk. In order to guide future conservation actions for the population, we evaluated the effects of different management scenarios that improve survival, fecundity, or both, on population growth and quasi‐extinction risk. Comparison of the estimated annual survival (juvenile and subadult survival: 0.66; adult survival: 0.71) and breeding parameters (clutch size: 2.3; hatching success: 0.45; fledging success: 0.83) with those of other harrier species suggests that adult survival and breeding parameters of Reunion harriers are low. A small data set collected 40 years ago suggests that the probability of an egg producing a fledgling was higher and has declined to the current low level. The population models project that the Reunion harrier population is declining and faces a high risk of quasi‐extinction in the next 40 years. Only management measures that simultaneously improve adult survival and fecundity could lead to a recovery of the population. These alarming results call for immediate conservation action aimed at rapidly improving the demographic rates.

“Heaven” of Data Deficient Species: The Conservation Status of the Endemic Amphibian Fauna of Vietnam

Predicting the true status of Data Deficient (DD) species is a prominent theme in recent conservation biology, but there still is much debate regarding the conservation approach that should be used for DD taxa and no definitive conclusions are yet available. We review and analyse the current data available on the conservation status of amphibians in Vietnam, with an emphasis on the DD species. We also compare Vietnamese DD frequency of occurrence with other regions of the world, examine the extent of the range of taxa divided by Red List status, and explore the protection attributes of the taxa based on their inclusion within protected areas of Vietnam. We documented that the analysis of amphibians in Southeast Asia, and especially in Vietnam, substantially agrees with patterns highlighted by previous global research, and confirms the risk that several DD species may silently go extinct without their actual risk ever being recognized. Importantly, our study showed that fine-scale analyses are essential to highlight the potential drivers of extinction risk for the DD species of amphibians. A crucial next step for conservation policies in Vietnam (and in surrounding countries) is developing and implementing species-specific studies targeted at addressing each species’ drivers of extinction and determining science-based strategies for minimizing their extinction risk.

Centers of Endemism and The Potential of Zoos and Botanical Gardens in Conservation of Endemics

Knowledge about ecological conditions and processes in centers of endemism (CoEs) is still limited with respect to various systematic groups of organisms, ecosystem types, ecological conditions, and ecosystem services. We review the characterization, identification, and meaning of CoEs. Endemics play an increasing and prominent role in nature conservation monitoring and management and in the organization of zoos, aquaria, and botanical gardens. We examine the importance of different groups of organisms and indicators for the characterization of endemic-rich regions, e.g., with regard to the richness of endemics per region and degree of endemism, the importance of heterogeneity in space, continuity in time, isolation, and ex situ management for the survival of endemic species. Currently, conversion of land cover and land use change are the most important causes of biodiversity decline and extinction risk of endemic and endangered species. These are followed by climate change, including severe weather, and then natural processes such as volcanism, landslides, or tsunamis. For conservation purposes, the management of regional land use, zoos, aquaria, botanical gardens, and social aspects of the diversity of endemics and CoEs have to be taken into account as well. We find that the ex situ representation of endemics in general is limited, and conservation networks in this regard can be improved. We need better answers to questions about the relationship between ecoregions, CoEs and regional awareness of endemism, which is linked with human culture including aesthetics, well-being, health, and trade.

Characterization factor estimation based on a species-specific extinction risk approach for determining CO2 emission impact on terrestrial biodiversity

Species extinction risk is a crucial indicator of the global impact of climate change on biodiversity. In life cycle impact assessment (LCIA), the relationship between the potentially extinct ratio and temperature is used to calculate characterization factors (CFs) that indicate additional biodiversity impact per unit greenhouse gas emissions, using the biodiversity loss indicator termed potentially disappeared fraction (PDF). However, current methods for calculating CFs that focus on terrestrial biodiversity do not show differences among taxa and regions. Here, we estimated taxon-level CFs based on a species-specific extinction risk approach for determining impact of CO2 emission on terrestrial biodiversity. The extinction risk of a species is defined as the reciprocal of the estimated waiting times for extinction caused by climate-derived habitat loss of the species. Based on the approach, CFs for five taxa—birds, reptiles, mammals, amphibians, vascular plants—were estimated as 0.017, 0.017, 0.025, 0.027, and 0.040 (PDF·km2·year·kton−1), respectively. In addition, CFs that use the number of potentially extinct species (species·kton−1) as indicators were also calculated based on the same species-specific extinction risk approach. The proposed method successfully calculates taxon-level CFs and has the potential to show their regional variations, which contributes to the precise impact assessment on climate-derived biodiversity in LCIA.