Search Results (14)

Understanding species from an ecological and phylogenetic perspective facilitates an understanding of their conservation status in relation to the changing world. The frog genus Pelophylax is among the largest in terms of amphibian biomass in the Palearctic, but species have not been thoroughly studied at the Asian continental scale. The phylogeographic relationship, behavioural ecology, and ecological requirements within the genus need clarification, despite generally good local coverage. Here, for the first time, we conducted a literature review focused on phylogeography and behavioural ecology, supported by ecological niche modelling of twelve Asian Pelophylax lineages. Finally, we compiled the known threats for each of the lineages. We first determined the presence of twelve species and species-candidate lineages. In terms of behavioural ecology, the main difference among lineages is the time to metamorphosis and the time to reach sexual maturity. The ecological models highlighted a match between the known presence of each clade and their suitable habitat and highlighted the Syr Darya drainage on the eastern shore of the Caspian Sea for the non-described Pelophylax “Syr Darya lineage”. Finally, we highlighted the greatest variation among lineages in terms of threats, as some lineages are threatened by numerous factors, whereas others are expanding. Full article

It is important to describe lineages before they go extinct, as we can only protect what we know. This is especially important in the case of microendemic species likely to be relict populations, such as Hynobius salamanders in southern China. Here, we unexpectedly sampled Hynobius individuals in Fujian province, China, and then worked on determining their taxonomic status. We describe Hynobius bambusicolus sp. nov. based on molecular and morphological data. The lineage is deeply divergent and clusters with the other southern Chinese Hynobius species based on the concatenated mtDNA gene fragments (>1500 bp), being the sister group to H. amjiensis based on the COI gene fragment, despite their geographic distance. In terms of morphology, the species can be identified through discrete characters enabling identification in the field by eye, an unusual convenience in Hynobius species. In addition, we noted some interesting life history traits in the species, such as vocalization and cannibalism. The species is likely to be incredibly rare, over a massively restricted distribution, fitting the definition of Critically Endangered following several lines of criteria and categories of the IUCN Red List of Threatened Species. Full article

University campuses are important components of cities, harboring the majority of urban biodiversity. In this study, based on monthly bird survey data covering 12 university campuses located either downtown or in the newly developed areas in Nanjing, China, in 2019, we studied the assembly processes of each campus’s bird population and their main drivers by modeling a set of ecological and landscape determinants. Our results showed that (1) bird abundance and species diversity in the newly developed areas were significantly higher than in those downtown; (2) the phylogeny of bird communities in all universities followed a pattern of aggregation, indicating that environmental filtering played a major role in community assembly; (3) specifically, grass, water, and buildings were the main factors affecting each campus’s bird community’s functional and phylogenetic diversity, with the areas of grass and water habitats having a significant positive correlation with phylogenetic diversity, while the size of building areas was negatively correlated. Our results emphasize that habitat features play a decisive role in determining urban bird population diversity and community assembly processes. We suggest that increasing landscape diversity, e.g., by reasonably arranging the location and area of water bodies and grasslands and improving the landscape connectivity, could be a powerful way to maintain and promote urban bird diversity. Full article

Although thermal tolerance along geographical gradients gives an insight into species’ response to climate change, current studies on thermal tolerance are strongly skewed towards global-scale patterns. As a result, intraspecific variations are often assumed to be constant, despite a lack of evidence. To understand population-specific responses to thermal stress, we investigated the presence of intraspecific variations in the critical thermal maximum (CTmax) of tadpoles in two anuran species, Rana uenoi and Bufo sachalinensis. The study was conducted across a five-degree latitudinal gradient in the Republic of Korea. We exposed the tadpoles to increasing temperatures and recorded the CTmax for 270 R. uenoi individuals from 11 sites, collected in rice paddies, and for 240 B. sachalinensis individuals from ten sites, collected in reservoirs. We also recorded the swimming performance and behavior of the tadpoles when placed in an experimental apparatus during CTmax measurements. We then used linear regressions to determine the relationship between abiotic factors and CTmax. In R. uenoi, we found a positive relationship between latitude and CTmax, but the tadpoles did not display specific thermoregulatory behaviors. In B. sachalinensis, none of the abiotic factors such as climate and geographic coordinates were related to CTmax, but we detected a tendency to swim close to the water surface when water temperature was increasing. For R. uenoi, we tentatively relate the CTmax variability across the latitudinal gradient to a physiological adaptive response associated with habitat characteristics that are assumed to be fluctuating, as the species inhabits small water bodies prone to drying out. In the case of B. sachalinensis, the behavior observed may be linked to oxygen depletion and thermoregulation, as it may buffer temperature changes in the absence of physiological adjustment. These findings suggest that intra-specific variations in CTmax are greater than generally accounted for, and thermal conditions of natural environments are important for understanding thermal tolerance in ectothermic species. Our results highlight that species’ specific responses to climate warmings need to be studied to better protect species against climate change. Full article

The reclamation of tidal flats is implicated in the declines of a large number of migratory waterbird species along the East Asia-Australasian Flyway, and has resulted in the assessment of Yellow Sea tidal flats as an Endangered habitat by the IUCN. Created in their present form by large-scale reclamation, the Hwaseong Wetlands on the Yellow Sea coast of the Republic of Korea are comprised of tidal flats, a large reclamation lake, and extensive areas of rice-fields and fallow land. As part of preparation for increased protections for these wetlands, we conducted bird surveys between late June 2020 and mid-June 2021. During this period, we recorded more than 150,000 waterbirds in the wetland and concentrations of 1% or more of 25 populations of waterbird. We also recorded a total of 16 globally threatened wetland species. As at many other coastal wetlands in the Yellow Sea, tidal flat obligate waterbird species used the tidal flats for foraging; and roosted in artificial wetlands which had been created through the reclamation process. The extensive areas of rice-field and other freshwater habitats in the Hwaseong Wetlands were also internationally important in their own right, supporting globally threatened amphibians and internationally important concentrations of foraging geese and floodplain-associated waterbird species. The movements of waterbirds between foraging and roosting areas we recorded make clear that conservation of the site’s biodiversity either as a Ramsar site or within a serial World Heritage Property would require protection of all the contiguous tidal flats and also of the most biodiverse rice-field and freshwater wetland areas. As elsewhere in the coastal zone of the Republic of Korea, this would first require the support of local stakeholders and also a reduction in jurisdictional issues between various local and national decision-making bodies. Full article

Amphibians are the most threatened vertebrate group on earth, and one of the reasons for their decline is habitat loss. While some populations have persisted in agricultural wetlands such as rice paddies, the current anthropisation of landscapes is dealing a new blow to the survival of these species. In rice paddies, the new threats are especially visible through the increased channelization of water bodies with increasingly efficient drainage ditches, which become deadly traps. We first conducted surveys over three years to determine the use of ditches by frog species for natural versus concrete ditches, and thus relate to habitat adequacy as well as the probability of becoming trapped in concrete ditches. We then set up four types of experimental arena for escape trials. Experiments were replicated for the Black-spotted pond frog (Pelophylax nigromaculatus), as a proxy for other species abundant in rice paddies in the Republic of Korea. We determined that a slope of at least 70 degrees, with engraved patterns, was the only set-up from which frogs managed to escape. We recommend the implementation of this type of device in areas where a high concentration of animals is trapped, before phasing out the ancient design and relying on amphibian-friendly drainage ditches as they also support higher amphibian biodiversity. Full article

Biodiversity in the Middle and Lower Yangtze Floodplain has critically decreased during the last several decades, driven by numerous determinants. Hence, identification of primary drivers of animal population decline is a priority for conservation. Analyzing long time-series data is a powerful way to assess drivers of declines, but the data are often missing, hampering effective conservation policymaking. In this study, based on twenty-four years (from 1996 to 2019) of annual maximal count data, we investigated the effects of climate and landscape changes on the increasing population trend of the Greater White-Fronted Goose (Anser albifrons) at a Ramsar site in the Middle and Lower Yangtze Floodplain, China. Our results showed that the availability of a suitable habitat and landscape attributes are the key driving forces affecting the population trend, while the effects of climate factors are weak. Specifically, increasing the area of suitable habitat and alleviating habitat fragmentation through a fishing ban policy may have provided a more suitable habitat to the geese, contributing to the increasing population trend. However, we also observed that the grazing prohibition policy implemented in 2017 at Shengjin Lake may have potentially negatively affected geese abundance, as grazing by larger herbivores may favor smaller geese species by modifying the vegetation community and structure. Based on our results, we suggest several practical countermeasures to improve the habitat suitability for herbivorous goose species wintering in this region. Full article

Determining the range, status, ecology and behaviour of species from areas where surveys and samplings are uncommon or difficult to conduct is a challenge, such as in the Democratic People’s Republic of Korea (DPR Korea). Here, we used genetic samples, field surveys, call recordings, photographic identification and a literature review to estimate the presence, range and status of amphibians in the DPR Korea. From our combined results and based on the IUCN Red List categories and criteria, we were able to estimate the national threat levels for most species. Our results demonstrated the presence of 18 native species and the suspected presence of Karsenia koreana and two Onychodactylus species. We reported the first record for Rana uenoi in the vicinity of Pyongyang using molecular tools and similarly confirmed the presence of Dryophytes japonicus at the same location. Based on distribution and modelling, we can expect the contact zone between species within the Rana and Onychodactylus genera to be located along the Changbai Massif, a mountain range that marks a shift in ecoregions and acts as a barrier to dispersion. The species richness was higher in the lowlands and at lower latitudes, with such areas populated by up to 11 species, while more northern regions were characterised by species richness of about half of that value. The combination of ecological models and known threats resulted in the recommendation of ten species as threatened at the national level following the IUCN Red List categories and criteria. This high number of threatened species was anticipated based on the high threat level to amphibians in bordering nations and globally. While the ecology of species in the DPR Korea is still understudied, we argue that species relying on agricultural wetlands such as rice paddies are not under imminent threat due to the enduring presence of extensive agricultural landscapes with low rates of chemical use and mechanisation. The maintenance of such landscapes is a clear benefit to amphibian species, in contrast to more industrialised agricultural landscapes in neighbouring nations. In comparison, the status of species dependent on forested habitats is unclear and threat levels are likely to be higher because of deforestation, as in neighbouring nations. Full article

It is important to understand the dynamics of population size to accurately assess threats and implement conservation activities when required. However, inaccurate estimates are harming both the threat estimation process, and the resulting conservation actions. Here, we address the extinction threats to Scincella huanrenensis, a species described in the People’s Republic of China, but also occurring on the Korean peninsula. Estimating the threats to the species is not an easy task due to its unknown population status in the Democratic People’s Republic of Korea. Here we analysed the literature to acquire the known presence point for the species, along with datapoints originating from opportunistic field surveys, and employed habitat suitability models to estimate the range of the species. We then followed the categories and criteria of the IUCN Red List of Threatened Species to assess the extinction risk of the species. We found the species not to be fitting the threatened category at the global scale based on the range size, the only category for which enough data was available. We recommend the status of the species on the IUCN Red List of Threatened Species to be updated as it is now listed as critically endangered (CR), a listing fitting a national assessment for the People’s Republic (PR) of China. While this species is possibly less threatened than currently listed, this is not a genuine improvement, and specific conservation aspects should not be neglected due to its specialisation to medium to high elevation habitat. Full article

Numerous amphibian species are declining because of habitat loss and fragmentation due to urbanization of landscapes and the construction of roads. This is a mounting threat to species restricted to habitats close to urban areas, such as agricultural wetlands in North East Asia. The Suweon treefrog (Dryophytes suweonensis) falls into the list of species threatened with habitat loss and most populations are under threat of extirpation. Over the last decades, sub-populations have become increasingly disconnected and specifically the density of paved roads has increased around the only site connecting northern and southern Seoul populations. We surveyed this locality in Hojobeol, Siheung, Republic of Korea in 2012, 2015 and 2019 to first confirm the decline in the number of sites where D. suweonensis was present. The second objective was to analyze the habitat characteristics and determine the remaining suitable habitat for D. suweonensis through a species distribution model following the maximum entropy method. Our results show that rice paddy cover and distance from the paved road are the most important factor defining suitable habitat for D. suweonensis. At this locality, uninterrupted rice paddies are a suitable habitat for the species when reaching at least 0.19 km², with an average distance of 138 ± 93 m² from the roads. We link the decrease in the number of sites where D. suweonensis is present with the decrease in rice paddy cover, generally replaced by localized infrastructures, greenhouses and habitat fragmentation. Rice paddies should remain connected over a large area for the protection of the remaining populations. In addition, habitat requirements should be integrated in the requisites to designate protected areas. Full article

Closely related individuals from different areas can see their morphologies change based on differences between clades, but also ecological variables such as the island effect or sympatry. This is the case of salamanders, which have adapted to a broad range of ecological niches, ranging from underground dwellers in xeric landscape to tropical arboreal habitats. On the Korean Peninsula, salamanders from the Hynobius clade are widespread on the mainland and islands, with several partially sympatric clades and candidate species. Currently, seven lineages have been identified based on mtDNA, four of them matching named species and three others for which the species status remains untested. While the morphology of Korean Hynobius is known to be variable between genetically segregated clades, we hypothesise that (1) the candidate species are morphologically different, and that (2) the island effect and (3) the sympatric status have significant impacts on the morphology of individuals within the genus. Here we measured 329 Hynobius salamanders from all seven clades, in areas of sympatry and allopatry, and on islands and on the mainland (Graphical Abstract A). We determined that the island effect had a significant impact on the morphology of the genus, with mainland individuals generally displaying a broader range of morphology than islandic individuals (Graphical Abstract B). We also determined that sympatry had an impact on morphology, with the sizes of individuals from clades in sympatric areas diverging from each other (Graphical Abstract C). Finally, we demonstrated that all seven clades have significantly different morphologies, and we described the three candidate species that had already been isolated based on mtDNA and microsatellite data: Hynobius notialis sp. nov., Hynobius geojeensis sp. nov. and Hynobius perplicatus sp. nov. We conclude that looking at morphology alone would be misleading about the true diversity of Hynobius species, and species in general, because of the island and patry effects. Full article

Threat assessment is important to prioritize species conservation projects and planning. The taxonomic resolution regarding the status of the “Dryophytes immaculatus group” and the description of a new species in the Republic of Korea resulted in a shift in ranges and population sizes. Thus, reviewing the IUCN Red List status of the three species from the group: D. immaculatus, D. suweonensis and D. flaviventris and recommending an update is needed. While the three species have similar ecological requirements and are distributed around the Yellow Sea, they are under contrasting anthropological pressure and threats. Here, based on the literature available, I have applied all IUCN Red List criterion and tested the fit of each species in each criteria to recommend listing under the appropriate threat level. This resulted in the recommendation of the following categories: Near Threatened for D. immaculatus, Endangered following the criteria C2a(i)b for D. suweonensis and Critically Endangered following the criteria E for D. flaviventris. All three species are declining, mostly because of landscape changes as a result of human activities, but the differences in range, population dynamics and already extirpated subpopulations result in different threat levels for each species. Dryophytes flaviventris is under the highest threat category mostly because of its limited range segregated into two subpopulations; and several known extirpated subpopulations. Immediate actions for the conservation of this species are required. Dryophytes suweonensis is present in both the Republic of Korea and the Democratic Republic of Korea (DPR Korea) and is under lower ecological pressure in DPR Korea. Dryophytes immaculatus is present in the People’s Republic of China, over a very large range despite a marked decline. I recommend joint efforts for the conservation of these species. Full article

Divergence-time estimation critically improves the understanding of biogeography processes underlying the distribution of species, especially when fossil data is not available. We hypothesise that the Asian black-spined toad, Duttaphrynus melanostictus, expanded into the Eastern Indomalaya following the Quaternary glaciations with the subsequent colonisation of new landscapes during the Last Glacial Maximum. Divergence dating inferred from 364 sequences of mitochondrial tRNAGly ND3 supported the emergence of a common ancestor to the three D. melanostictus clades around 1.85 (±0.77) Ma, matching with the Lower to Mid-Pleistocene transition. Duttaphrynus melanostictus then dispersed into Southeast Asia from the central Indo-Pacific and became isolated in the Southern Sundaic and Wallacea regions 1.43 (±0.10) Ma through vicariance as a result of sea level oscillations. The clade on the Southeast Asian mainland then colonised the peninsula from Myanmar to Vietnam and expanded towards Southeastern China at the end of the Mid-Pleistocene Revolution 0.84 (±0.32) Ma. Population dynamics further highlight an expansion of the Southeast Asian mainland population towards Taiwan, the Northeastern edge of the species’ range after the last interglacial, and during the emergence of the Holocene human settlements around 7000 BP. Thus, the current divergence of D. melanostictus into three segregated clades was mostly shaped by Quaternary glaciations, followed by natural dispersion events over land bridges and accelerated by anthropogenic activities. Full article

Amphibians are in the midst of a sixth mass extinction, and human activities play a major role in pushing species towards extinction. Landscape anthropisation has impacts that indirectly threaten species, in addition to the obvious destruction of natural habitats. For instance, land modification may bring human-commensal species in contact with sister-clades from which they were previously isolated. The species in these new contact zones are then able to hybridise to the point of reaching lineage fusion, through which the gene pool of the two species merges and one of the parental lineages becomes extirpated. Here, we documented the patterns of hybridisation between the spatially restricted D. suweonensis and the widespread D. japonicus. On the basis of the analysis of Cytochrome c oxidase subunit I mitochondrial DNA sequences (404 individuals from 35 sites) and six polymorphic microsatellites (381 individuals from 34 sites), we revealed a generalised, bi-directional, and geographically widespread hybridisation between the two species. Evidence of fertile back-crosses is provided by relatively high numbers of individuals in cyto-nuclear disequilibrium, as well as the presence of hybrid individuals further south than the species distribution limit, determined on the basis of call properties. Hybridisation is an additional threat to the endangered D. suweonensis. Full article