High Risk Of Extinction Research Articles

Range restriction, climate variability and human‐related risks imperil lizards world‐wide

AbstractAimsIdentifying major reasons for species imperilment is a necessary step for conservation, but the degree to which we can generalize is hard for species‐rich yet less‐studied taxa, such as lizards. Here, we aim to bridge the gap by providing comprehensive analyses of the correlates and processes of species extinction and threats for global lizards.LocationGlobal.Time periodCurrent.Major taxa studiedLizards.MethodsWe compiled a dataset comprising extinction risk status, six intrinsic traits and seven extrinsic factors for 5256 lizard species. We carried out binomial distribution tests for 43 families and seven realms to check the non‐randomness in species extinction risk and used phylogenetic linear regressions to identify the key factors that relate to the extinction proneness of lizards and species subgroups. Based on the International Union for Conservation of Nature (IUCN) threat assessment, we identified major threats for global lizards and for major families and regions.ResultsWe found strong evidence of taxonomic and geographical non‐randomness in the extinction risk of lizards. Geographical range size, human footprint and density, insular endemism, temperature and precipitation seasonality, and body size were key predictors of extinction risk, and the first three factors were also important across families and realms. Moreover, newly described species were more likely to have a restricted range size and a higher extinction risk. Globally, the most detrimental threat was habitat destruction, while overexploitation, species invasion and climate change varied widely in importance among species groups.Main conclusionsOverall, we highlight the detrimental influences of range restriction, climate variability and anthropogenic threats to species persistence. We suggest that lizards are potentially at high risk of extinction owing to widespread human disturbance and that species with extinction‐prone traits require conservation prioritization. Moreover, lizards of different families and regions require different management strategies because of variation in extinction‐risk correlates and threats.

Viability analysis for population reinforcement of Grauer's gorillas at Mount Tshiaberimu, Democratic Republic of the Congo

AbstractReintroduction and translocation programs have been sparingly used for the management of endangered primate populations. Mount Tshiaberimu in eastern Democratic Republic of the Congo (DRC) contains 6 Grauer's gorillas (Gorilla beringei graueri) with only 2 adult females. Without intervention, this population is at high risk of extinction. We designed population viability analysis models to compare different release scenarios of wild‐born captive female gorillas housed at the Gorilla Rehabilitation and Conservation Education (GRACE) Center in the DRC. We identified the minimum number of females needed to maintain a viable population in this habitat. We used a stochastic Leslie matrix model and a more complex individual‐based model to project population growth. We used published demographic parameters for mountain gorillas (Gorilla b. beringei) corresponding to a 3.2% annual growth rate, and then applied a correction factor to female fertility to obtain parameters consistent with 1% and 2% growth rates. We ran each scenario over a 50‐year time period (1,000 simulations) to determine the final population size and risk of local extinction. Results from our optimistic (3.2% growth) and conservative (1% growth) individual‐based model projections indicated that the extinction risk dropped below 1% with the release of at least 2 or 3 females, respectively. Both approaches predicted similar extinction risks for all scenarios; however, the variance in final population size was higher with the individual‐based model. For long‐lived mammals like primates, we recommend the use of individual‐based models, which can incorporate life‐history parameters such as long gestation and nursing periods. Our analysis suggests a translocation of ≥3 females to rescue the Tshiaberimu gorilla population in the short term. Factors such as inbreeding depression, habitat quality, disease risks, and anthropogenic pressures will need to be evaluated in later stages of population reinforcement planning.

Population distribution, connectivity and differentiation of Indo‐Pacific humpback dolphins in Chinese waters: Key baselines for improving conservation management

Abstract Humpback dolphins (Sousa spp.), throughout their distribution ranges, are often designated as flagship species for coastal ecosystem conservation. Most of the early research on humpback dolphins was carried out in Chinese waters, and in the last two decades, numerous studies have provided abundant conservation‐valuable findings. In this study, a systematic review was conducted to gain a comprehensive understanding of the distributional ecology of humpback dolphins in Chinese waters, to establish an updated national knowledge base about key conservation baselines on this flagship species. Currently, there are at least eight main distribution areas of humpback dolphins along the coast of southern China, representing a clear picture of place‐based conservation units. However, the overall biogeographical distribution pattern is discontinuous, and existing marine protected areas are far from sufficient to protect these key areas for the survival of humpback dolphins. Based on the photo‐identification technique, cross‐matching of humpback dolphin individuals revealed extremely low inter‐population connectivity among most of the known populations. Genetic studies suggested that several examined populations have low haplotype diversity levels, with limited inter‐population gene flow. Morphological and behavioural evidence also supports population differentiation among geographical locations. These findings provide key baselines for the promotion of conservation management initiatives for humpback dolphins in Chinese waters. All recognizable geographical populations, together with each key habitat, should be considered as independent conservation units. With small distribution areas, low genetic diversity and unfavourable geographical isolation, several populations may be at a high risk of regional extinction. A country‐led scheme with cross‐regional collaboration is required for science‐based, action‐focused and timely conservation efforts. Future conservation management initiatives should aim to increase or at least maintain key habitats, inter‐population connectivity, population‐level genetic diversity and effective population size.

A DNA barcode reference library for CITES listed Malagasy Dalbergia species.

On Madagascar, the illegal and unsustainable exploitation and illegal international trade of Dalbergia (rosewood) precious woods remain a serious conservation problem. Members of this genus are at high risk of extinction as a consequence of logging, mining, and slash and burn agriculture. Morphological identification of these Malagasy species is difficult in the absence of flowers and fruits, especially in the case of cut trees, sawn wood, and finished product. In this study, we use molecular barcoding to identify the Dalbergia species with the intent to contribute to the control of their illegal trade. Thirty-six Dalbergia samples representing 12 Malagasy species of which 11 have high commercial value, were collected to test the efficacy of a region of the plastid genome (rbcL) and a nuclear-transcribed ITS for barcoding. These widely used markers, as well as DNA barcoding gaps, "best match" and "best close match" approaches, and the neighbor-joining method were employed. All samples were amplified and sequenced using the two markers. Using a single locus, the "best match" and "best close match" approaches revealed that ITS has high discriminatory power within the tested Malagasy species. The combination of rbcL + ITS revealed 100% species discrimination. This study confirms that ITS alone and in combination with chloroplast barcode rbcL allow non-ambiguous identification for the 12 species studied. The results contribute to the development of DNA barcoding as a useful tool to identify Malagasy Dalbergia and suggest that the approach developed should be expanded to all 56 potentially exploited species in reference to international CITES requirements and the sustainable management of valuable resources.

THE EFFECT OF DIFFERENT PRE-SOWING TREATMENTS ON BREAKING SEED DORMANCY IN BAOBAB (Adansonia digitata L.) PLANT

Seed germination of baobab has necessitated with quiescence and hard seed coat impermeable to water and gases. It faces a high risk of extinction due to lack of regeneration. An experiment was carried out to investigate the effect of pre-sowing treatment techniques on seed germination of Baobab. Pot trials were conducted during 2021 dry season at Biological garden, Department of Plant Science and Biotechnology, Faculty of Life Science, Federal University Dutsin-Ma, Katsina State using completely randomized design (CRD). Seeds were subjected to four different concentrations of sulphuric acid, hot water, cold water, physical treatment and untreated seed as control and were analyzed independently to obtain the best treatment periods. Total of nine hundred and sixty (960) viable seeds were surface sterilized in 1.0% Sodium-hypochlorite (NaOCl) for 1 minute and rinsed three (3) times in sterile distilled water. 20 viable seeds were sown for each polypot. Physical pre-sowing treatment with full-sided scarification and treatment with hot water for 10 minutes produces the highest germination percentage (95.00%) and early seedling emergence (7th day after sowing). Seeds soaked in cold water for 8.00 hours gave the least mean days of seedling emergence (6th day after sowing) when compared to other treatments. These results suggested that full side scarification, soaking seed in hot water for 10 minutes and cold water for 8.00 hours were optimum in breaking seed dormancy in Baobab and the techniques could be apply prior to planting to improve germination performance.

Extinct in the wild: The precarious state of Earth’s most threatened group of species

Extinct in the Wild (EW) species are placed at the highest risk of extinction under the International Union for Conservation of Nature Red List, but the extent and variation in this risk have never been evaluated. Harnessing global databases of ex situ animal and plant holdings, we report on the perilous state of EW species. Most EW animal species-already compromised by their small number of founders-are maintained at population sizes far below the thresholds necessary to ensure demographic security. Most EW plant species depend on live propagation by a small number of botanic gardens, with a minority secured at seed bank institutions. Both extinctions and recoveries are possible fates for EW species. We urgently call for international effort to enable the latter.

Quantifying rarity of intraspecific diversity at multiple spatial scales by combining fine-grain citizen-based data across national boundaries

Quantifying rarity at the intraspecific level is an important task for conservation biologists because rare phenotypes have a higher extinction risk than common ones. However, quantitative assessments of rarity are lacking at this level, preventing to adequately protect rare and endangered variants that are part of the pool of common species. Our aim was to take benefit of high-resolution volunteer-based occurrence data to assess quantitatively rarity patterns of facultative paedomorphosis, in the Alpine newt (Ichthyosaura alpestris). This polyphenism is composed of two morphs, a rare adult phenotype retaining gills and a common phenotype metamorphosing. We included multiple spatial scales (i.e., resolution) and combined 15,613 occurrence records from the atlas databases of the seven countries in the European Alps to understand how spatial scale may affect rarity metrics. Our analyses revealed that the rarer phenotype was 292 times rarer than the common phenotype, occupying a very small and fragmented area of occupancy. Yet, rarity depended on the spatial resolution of the data. Rarity estimates were up to 1300 times lower at the coarser than at the finer spatial scale. Both the rarity of the rare phenotype and the presence of threats (i.e., fish introductions) make paedomorphs critically endangered whereas the common phenotype was widespread at all spatial scales. Altogether, these results show how rarity metrics can differ between spatial scales for rare and common organisms, suggesting that fine-grain data should be used to assess intraspecific rarity. They also show that combining datasets from distribution atlases is efficient to estimate rarity.

A multi-method approach for assessing the distribution of a rare, burrowing North American crayfish species.

Primary burrowing crayfishes face high extinction risk, but are challenging to study, manage, and conserve due to their difficult-to-sample habitat (i.e., terrestrial burrows) and low population densities. We apply here a variety of methods to characterize the distribution, habitat associations, and conservation status of the Boston Mountains Crayfish Cambarus causeyi (Reimer, 1966), an endemic burrowing crayfish found only in the Ozark Mountains of Arkansas, United States. We used species distribution modeling (SDM) on historic occurrence records to characterize the distribution and macro-scale habitat associations of this species. We then ground-truthed SDM predictions with conventional sampling, modeled fine-scale habitat associations with generalized linear models (GLM), and lastly developed and tested an environmental DNA (eDNA) assay for this species in comparison to conventional sampling. This represents, to our knowledge, the first successful eDNA assay for a terrestrial burrowing crayfish. Our MaxEnt-derived SDM found a strong effect of average annual precipitation on the historic distribution of C. causeyi, which occurred most frequently at locations with moderately high average annual precipitation (140-150 cm/yr) within our study region. Cambarus causeyi was difficult to detect by conventional sampling in 2019 and 2020, found at only 9 of 51 sites (17.6%) sampled by searching for and manually excavating crayfish burrows. Surprisingly, habitat suitability predicted from our MaxEnt models was not associated with contemporary C. causeyi occurrences per GLMs. Instead, C. causeyi presence was negatively associated with both sandy soils and the presence of other burrowing crayfish species. Poor SDM performance in this instance was likely caused by the omission of high resolution fine-scale habitat data (e.g., soils) and biotic interactions from MaxEnt models. Finally, our eDNA assay detected C. causeyi from six of 25 sites (24.0%) sampled in 2020, out-performing conventional surveys by burrow excavation for this species. Given the difficulty of studying primary burrowing crayfishes and their high conservation need, we propose that eDNA may become an increasingly important monitoring tool for C. causeyi and similar species.

Priority conservation areas and a global population estimate for the critically endangered Philippine Eagle

AbstractMany range‐restricted taxa are experiencing population declines, yet we lack fundamental information regarding their distribution and population size. Establishing baseline estimates for both of these key biological parameters is however critical for directing conservation planning for at‐risk range‐restricted species. The International Union for the Conservation of Nature (IUCN) Red List uses three range metrics that define species distributions and inform extinction risk assessments: extent of occurrence (EOO), area of occupancy (AOO) and area of habitat (AOH). However, calculating all three metrics using standard IUCN approaches relies on a geographically representative sample of locations, which for rare species is often spatially biased. Here, we apply model‐based interpolation using Species Distribution Models (SDMs), correlating occurrences with remote‐sensing covariates, to calculate IUCN range metrics, protected area coverage and a global population estimate for the Critically Endangered Philippine Eagle (Pithecophaga jefferyi). Our final range wide continuous SDM had high predictive accuracy (continuous Boyce Index = 0.934) and when converted to a binary model estimated an AOH as 28 624 km2, a maximum EOO as 617 957 km2, and a minimum EOO as 275 459 km2, with an AOO as 53 867 km2. Based on inferred habitat from the AOH metric, we estimate a global population of 392 breeding pairs (range: 318–447 pairs), or 784 mature individuals, across the Philippine Eagle global range. Protected areas covered 32% of AOH, 13% less than the target representation, with the continuous model identifying key habitat as priority conservation areas. We demonstrate that even when occurrences are geographically biased, robust habitat models can quantify baseline IUCN range metrics, protected area coverage and a population size estimate. In the absence of adequate location data for many rare and threatened taxa, our method is a promising spatial modelling tool with widespread applications, particularly for island endemics facing high extinction risk.

Overview of the Success of In Vitro Culture for Ex Situ Conservation and Sustainable Utilization of Endemic and Subendemic Native Plants of Romania

Romania has a relatively high diversity of plant species, including 3829 vascular and 979 non-vascular spontaneous plant taxa (species and subspecies). Due to uncontrolled harvesting as well as other causes, including climate change and ecological collapse, the speed of species extinction and the narrowing of the genetic base of plant resources has been reported as a critical issue. Therefore, the national Red List of Romanian flora includes 1453 threatened taxa, of which 95 are endemic and 90 subendemic. Many of these have high ornamental, medicinal–cosmetic, and/or aromatic properties. The high extinction risk of these valuable plants has stimulated both the reconsideration of their vital importance as genetic resources and interest in finding effective methods for conservation. Cultivating these phytogenetic resources in a human-controlled environment is of high importance for effective ex situ conservation, which can further serve sustainable exploitation needs and may facilitate in situ conservation actions. In vitro culture is a powerful tool for producing elite plants for cultivation for different purposes. This review summarizes the current knowledge on in vitro multiplication of 22 endemic and subendemic native plants of Romania, examining the materials used, the treatments applied, and the results obtained in each stage of the micropropagation protocol (culture initiation, proliferation, rooting, and acclimatization). The findings from the reviewed studies are presented in a comparative way, and the potential of plant tissue culture in conservation and sustainable exploitation of these Romanian species is outlined.

Populations of a tropical epiphytic orchid are destabilized in its peripheral range by hurricane and an exotic herbivore

AbstractIn a time of global change, having an understanding of the nature of biotic and abiotic factors that drive a species' range may be the sharpest tool in the toolbox of conservation and management of threatened species. However, such information are lacking for most tropical and epiphytic species due to the complexity of life history, the roles of stochastic events, and the diversity of habitat across the span of a distribution. In this study, we conducted repeated census across the core and peripheral range of Trichocentrum undulatum, a threatened orchid that is found throughout the island of Cuba (species core range) and southern Florida (the northern peripheral range). We used demographic matrix modeling and stochastic simulations to investigate the impacts of herbivory, hurricanes, and logging (in Cuba) on projected population growth rates (λ and λs) among sites. Our study indicates that the Florida population is under high extinction risk and most populations in the core range show less interannual variability, but, with the exception of one population, are also in decline. The peripheral population experienced higher herbivory damage than did the core populations, by a native inflorescence‐crippling fly, Melanagromyza miamensis, and an invasive, mortality‐triggered scale, Diaspis boisduvalii. The latter was found in the Florida population only. Hurricanes increased levels of mortality and had a negative effect on λ. However, λ increased following hurricane events due to increased recruitment and decreased herbivory. Life table response experiments suggest that higher adult survival was the largest contributor to the higher λ observed in the growing Cuba populations, as compared with the population in Florida. Logging simulations in Cuba indicate that populations can maintain stability only if selective logging of host trees occurs at low frequency. Reintroduction of the species in its northern peripheral habitat is needed to ameliorate the threats from sea‐level rise and invasive herbivorous insects to secure the current species' northern, continental range margin. Our study exhibits how vital rates and ecological interactions vary across a species distribution and respond under differing stochastic events.

Remaining forests on the Central Highlands of Madagascar-Endemic and endangered aquatic beetle fauna uncovered.

Madagascar is known for its high endemism and as many as 90% of this unique diversity are forest-dwellers. Unfortunately, the forest cover of Madagascar is decreasing at an alarming rate. This decrease can also affect aquatic insects, but our knowledge on aquatic insect diversity and distribution on Madagascar are limited. Although the eastern rainforests are considered the most diverse, the Central Highlands of Madagascar also harbors unique microendemic fauna but has been less studied. Here, we analyze the aquatic Adephaga beetle fauna of three remaining protected forests of the Central Highlands. Diversity, abundance, and uniqueness are compared between and within natural forests and surrounding grasslands. At least 15 undescribed species were found, highlighting the Central Highlands as an important area for endemism. The natural forests and the surrounding grasslands differed significantly in species assemblages. Interestingly, the three remaining forests differed in their assemblages with the geographically more distant Manjakatompo Ankaratra having the most unique fauna but also the highest altitude span. By contrast, the species composition was similar between the peripheral zones of each of the three remaining forests. The similarity of the fauna in the peripheral open habitats illustrates how some local forest endemics are replaced with widespread generalists in degraded habitats. Our study shows that the remaining forests of the Central Highlands of Madagascar are important refuges of unique fauna at high risk of extinction.

Molecular systematic analysis of the genus Notelaea (Oleaceae): SNPs from high‐density DArT‐sequencing unravel the mystery of the species limits of threatened species of Notelaea

AbstractConservation decision‐making and prioritization of management actions for taxa at high risk of extinction require a clear understanding of systematic relationships and species boundaries. Taxonomic uncertainty surrounds two threatened species of native olive (genus Notelaea) endemic to Australia. Notelaea ipsviciensis is known from only one small population and is listed as critically endangered under Australian and Queensland legislation, while Notelaea lloydii is listed as vulnerable due to its restricted distribution in south‐east Queensland, Australia. Notelaea ipsviciensis occurs in sympatry with N. lloydii, at the only site where it is found, and exhibits intermediate morphology between N. lloydii and Notelaea ovata raising speculation that it is a natural hybrid of the two. To address this uncertainty, we have reconstructed the molecular phylogeny of the genus Notelaea using both single‐gene sequencing and single nucleotide polymorphism (SNP) data. While the chloroplast DNA markers were not found to be informative, the genome‐wide SNPs used in this study have unequivocally resolved the long‐standing question of the hybrid origin of N. ipsviciensis. Results of the phylogenetics and hybrid analyses of SNP data show that N. ipsviciensis is a natural hybrid of N. lloydii and N. ovata, and the taxon's circumscription needs to be re‐evaluated. Our results also revealed unclear species boundaries among numerous other Notelaea species, including the threatened N. lloydii, indicating that further investigation and taxonomic revision may be necessary.

Bird extinctions threaten to cause disproportionate reductions of functional diversity and uniqueness

Abstract Human activities are driving rapid defaunation of Earth's ecosystems through increasing rates of extinction. However, the ecological consequences of species loss remain unclear, in part due to the limited availability of high‐resolution functional trait data. To address this, we assess how predicted extinctions will reshape avian functional diversity quantified using a multidimensional trait space, or morphospace, reflecting variation in eight key morphological traits closely linked to ecological function across 9943 (>99%) extant bird species. We show that large regions of this morphospace are represented by very few species and, thus, vulnerable to species loss. We also find evidence that species at highest risk of extinction are both larger and functionally unique in terms of ecological trait dimensions unrelated to size, such as beak shape and wing shape. Although raw patterns suggest a positive relationship between extinction risk and functional uniqueness, this is removed when accounting for phylogeny and body mass, indicating a dominant role for clade‐specific factors, including the combination of larger average body size and higher extinction risk in the non‐passerine clade. Regardless of how a threat is related to uniqueness, we show using simulations that the loss of currently threatened bird species would result in a greater loss of morphological diversity than expected under random extinctions. Our results suggest that ongoing declines of threatened bird species may drive a disproportionately large loss of morphological diversity, with potentially major consequences for ecosystem functioning. Read the free Plain Language Summary for this article on the Journal blog.

Functional Diversity and Primary Production Predict Future Patterns of Periphyton Productivity after Species Extinction

Understanding of the trait-based ecology of the periphytic algal community has increased in the last decade. However, the relationship between their functional diversity and ecosystem functions, such as primary production, has been speculated on, but yet not proven. Human impacts promote changes in biotic communities leading to a risk of extinction, with consequences for the functioning of aquatic ecosystems. In this study, we unraveled the associations between the taxonomic and functional components of periphytic algal diversity, stream eutrophication, and productivity patterns. Furthermore, we simulated future patterns of species extinction to predict how productivity may change when facing extinction. Primary production and taxonomic and functional diversity of the periphytic algal communities were estimated in five streams across a trophic gradient in the Ave River basin (northwest Portugal). Our results demonstrated that eutrophication led to a unimodal pattern of taxonomic diversity, while functional diversity tended to increase with increasing eutrophication. We found that only functional diversity had a positive association with primary production. The extinction estimations indicated that almost all species found in our study were at high extinction risk. When we spatially scaled our extinction simulations, we found poor-productive streams after the extirpation of a few species. However, at the regional scale, the ecosystem supports the extinction of at least 40% of species before turning into a poor-productive system. Intermediate levels of disturbance are probably beneficial for the diversity of periphytic algal communities, to a certain extent. Moreover, functionally diverse communities were more productive, and the alleged future extinction of species is likely to lead to poor-productive streams if regionally focused conservation initiatives are not implemented. We recommend that, using simulations of functional extinction, it is possible to infer how the loss of these microorganisms could alter ecosystem functioning, to better predict human impacts on aquatic ecosystems.

Extinction risk of Chinese angiosperms varies between woody and herbaceous species

AbstractAimUnderstanding how species' traits and environmental contexts relate to extinction risk is a critical priority for ecology and conservation biology. This study aims to identify and explore factors related to extinction risk between herbaceous and woody angiosperms to facilitate more effective conservation and management strategies and understand the interactions between environmental threats and species' traits.LocationChina.TaxonAngiosperms.MethodsWe obtained a large dataset including five traits, six extrinsic variables, and 796,118 occurrence records for 14,888 Chinese angiosperms. We assessed the phylogenetic signal and used phylogenetic generalized least squares regressions to explore relationships between extinction risk, plant traits, and extrinsic variables in woody and herbaceous angiosperms. We also used phylogenetic path analysis to evaluate causal relationships among traits, climate variables, and extinction risk of different growth forms.ResultsThe phylogenetic signal of extinction risk differed among woody and herbaceous species. Angiosperm extinction risk was mainly affected by growth form, altitude, mean annual temperature, normalized difference vegetation index, and precipitation change from 1901 to 2020. Woody species' extinction risk was strongly affected by height and precipitation, whereas extinction risk for herbaceous species was mainly affected by mean annual temperature rather than plant traits.Main conclusionsWoody species were more likely to have higher extinction risks than herbaceous species under climate change and extinction threat levels varied with both plant traits and extrinsic variables. The relationships we uncovered may help identify and protect threatened plant species and the ecosystems that rely on them.

Conservation of endangered galaxiid fishes in the Falkland Islands requires urgent action on invasive brown trout

Non-native salmonids are protected in the Southern hemisphere where they sustain aquaculture and lucrative sport fisheries, but also impact many native fishes, which poses a conservation conundrum. Legal protection and human-assisted secondary releases may have helped salmonids to spread, but this has seldom been tested. We reconstructed the introduction of brown trout (Salmo trutta) to the Falkland Islands using historical records and modelled its dispersal and probability of invasion using a generalized linear model and Leave One out Cross Validation. Our results indicate that establishment success was ~ 88%, and that dispersal was facilitated over land by proximity to invaded sites and density of stream-road crossings, suggesting it was human assisted. Brown trout have already invaded 54% of Falkland rivers, which are 2.9–4.5 times less likely to contain native galaxiids than uninvaded streams. Without strong containment we predict brown trout will invade nearly all suitable freshwater habitats in the Falklands within the next ~ 70 years, which might put native freshwater fishes at a high risk of extinction.

Genetic Diversity and Population Structure of the Giant Mottled Eel, Anguilla marmorata Quoy & Gaimard, 1824 in Central Vietnam

The giant mottled eel, Anguilla marmorata, is at high risk of extinction due to overfishing of glass eels and elvers to provide stock for eel farming. In Vietnam, information on the genetic diversity and population structure of this species, which is necessary for resource management, is limited. In order to address this paucity of information, sequencing of the entire mitochondrial control region (mtDNA) was carried out for 176 individuals collected from central Vietnam. The sequences were investigated using various genetic, phylogenetic and population analyses. A total of 165 distinct haplotypes were identified. The percentage of variation within and among populations was 99.26% and 0.74%, respectively. The fixation index was low (0.007) and not significant (p = 0.096). Therefore, panmixia and a lack of significant population genetic structuring seem likely for A. marmorata in central Vietnam. Most sampled eels were genetically similar to eels found in North Pacific populations (Japan, Taiwan and the Philippines), except for one sample from Quang Tri and two samples from Binh Dinh, which had high values of genetic identity (97% to 99%) with South Pacific populations (Tahiti, Fiji, New Caledonia and Papua New Guinea). Taken together, we suggest that A. marmorata from the North and South Pacific populations co-exist in central Vietnam.

Rediscovery and conservation of Lithocarpus kostermansii Soepadmo (Fagaceae), an endemic and endangered tree species in Java, Indonesia

Lithocarpus kostermansii Soepadmo (Fagaceae) is an endemic tree confined to the western part of Java Island, Indonesia. The IUCN Red List classifies the species as Endangered (EN) based on the assessment conducted more than 20 years ago. The species is not known to be present in ex-situ collections. After more than 5 decades since the last herbarium specimen was collected in 1964, here we reported the rediscovery of L. kostermansii in Sawarna, Lebak Regency, Banten Province. The species identity was confirmed by comparing the herbarium and living specimens newly collected with the type specimen image and protologue description. This study contributes new information on the tree morphology through photos of living plants made in the field. It also updates the threats to its natural habitat and provides additional locality information for the species. To enhance the conservation of the species, we collected and cultivated saplings of the species and these are growing in Bogor Botanic Gardens as part of their ex-situ conservation collections. Based on our findings, we proposed a new IUCN Red List assessment for L. kostermansii of EN A2c, B1 + 2ab(i,ii) as it is considered to be facing a very high risk of extinction in the wild due to forest degradation and land conversion.

Evolutionary dynamics inform management interventions of a hanging garden obligate, Carex specuicola

Uncovering the historical and contemporary processes shaping rare species with complex distributions is of growing importance due to threats such as habitat destruction and climate change. Species restricted to specialized, patchy habitat may persist by virtue of life history characteristics facilitating ongoing gene flow and dispersal, but they could also reflect the remnants of formerly widespread, suitable habitat that existed during past climate regimes. If formerly widespread species did not rely upon traits facilitating high dispersibility to persist, contemporary populations could be at high risk of extirpation or extinction. Fortunately, genomic investigations provide an opportunity to illuminate such alternative scenarios while simultaneously offering guidance for future management interventions. Herein, we test the role of these mechanisms in shaping patterns of genomic diversity and differentiation across a highly restricted and rare ecosystem: desert hanging gardens. We focus on Carex specuicola (Cyperaceae), a hanging garden obligate narrowly distributed in the Four Corners region of the southwestern United States that is listed as Threatened under the United States Endangered Species Act. Population structure and diversity analyses reveal that hanging garden populations are shaped by strong genetic drift, but that individuals in gardens are occasionally more closely related to individuals at other gardens than to individuals within the same garden. Similarly, gardens separated by long geographic distances may contain individuals that are more closely related compared to individuals in gardens separated by short geographic distances. Demographic modeling supports historical gene flow between some contemporary garden pairs, which is corroborated by low estimates of inbreeding coefficients and recent divergence times. As such, multiple lines of evidence support dispersal and gene flow across C. specuicola populations at both small and large spatial scales, indicating that even if C. specuicola was formerly more widespread, it may be well suited to persist in hanging gardens so long as suitable habitat remains available. Analyses like those demonstrated herein may be broadly applicable for understanding the short- and long-term evolutionary processes influencing rare species, and especially those having complex distributions across heterogeneous landscapes.