Resurvey After 20 Years:Updating the Distribution,Population,and Potential Threats of the Chinting Alpine Toad

Considering the increased anthropogenic impacts,species with a limited range and low detectability often lack fundamental information and conservation actions,placing them at a high risk of endangerment.The Chinting alpine toad Scutiger chintingensis is a rare mountain amphibian endemic to the eastern margin of the Qinghai-Xizang Plateau in China.Within its whole distribution range,only three known populations(Wolong,Emei,and Wawu)exist and no recent population status report has been documented for this species over the past two decades.From 2020 to 2023,we investigated the species distribution,and assessed the risk factors for the main populations.We recorded this species in all distribution areas,and updated a new distribution site with a lower elevation limit.The relative population density was 0.024±0.012 ind./m^(2)on Mount Emei,whereas only 0.008±0.017 ind./m^(2)on Mount Wawu.No significant difference was observed in the number of individuals between the two populations;however,the relative population density was significantly different.Sewage and waste discharge resulting from the construction of scenic areas,as well as disturbances from tourism,were the primary anthropogenic factors that influenced the survival of this species.Our results provide the updated information on the distribution and population status of the Chinting alpine toad,and suggest that unrecorded populations,as well as a wider elevation range,may exist for this species.Our findings emphasise the importance of timely updates of species distribution and population information and offer a basis for the future conservation of endangered amphibians.

Comparative analysis of the intestinal tract microbiota and feeding habits of five sympatric flycatchers

Gut microbiota and host interactions co-evolve and develop into stably adapted microbial communities and play vital roles in maintaining the health of organisms.Diet is supposed to be an important driver of differences in gut microbiota,but previous studies would commonly use literature depictions,which are essential but inaccurate,to explain the effects of diet on the gut microbiota of wild birds.In this study,we collected intestinal samples from five sympatric flycatchers to compare the gut microbial differences using bacterial 16S rRNA genes from Illumina MiSeq platform.Over 1,642,482 quality-filtered sequences from 1816S rRNA libraries were obtained and distinct compositions and diversities of gut microbiota were found in five flycatchers.Their gut microbiota is mainly from the four bacterial phyla of Proteobacteria,Firmicutes,Actinomycetes,and Bacteroidetes,but at the genus level showed a significant difference.Functional predictions revealed that the metabolic capacity of the gut microbiota of five flycatchers is greatly distinguished at KEGG level 3.And multiple food fragments showed a significant correlation with gut microbiota.Besides,the significant differences in the specific composition of the diets of the five insectivorous flycatchers indicated the differentiation of dietary niches.The study of the gut microbiota and feeding habits of sympatric flycatchers would increase the understanding of the gut microbial diversity of wild birds,and also improve our cognition of the co-evolution and co-adaptation within the host gut microbiota relations.

Altitudinal migration behavior patterns of birds on the eastern slope of Mt.Gongga,China

Many bird species in montane regions exhibit altitudinal migration behavior;however,altitudinal migration of birds is still understudied,especially in Asia.Mt.Gongga(7556 m) is the highest peak of the Hengduan Mountains in Southwest China.The steep elevation gradient and the high bird diversity make the eastern slope of Mt.Gongga(Hailuo Valley) an ideal place for studying the altitudinal migration behavior patterns of birds.We synchronously recorded the local bird diversity,temperature and humidity at two sites(1800 and 3000 m a.s.l.) during three migration seasons from September 2020 to June 2021 to identify birds exhibiting altitudinal migration behavior.During our surveys,we recorded 146 bird species in total and 20 passerine bird species were altitudinal migrants according to our altitudinal migration formula.Among those 20 altitudinal migrant species,eight bird species displayed a typical altitudinal migration pattern(upward migration during the breeding season and downward migration during the non-breeding season).Moreover,temperature was correlated with the daily number of individuals(DNI) at each study site.Therefore,increasing temperatures possibly caused upward migration of birds(DNI decreased at 1800 m and increased at 3000 m) and vice versa.To further elaborate,the Rufousgorgeted Flycatcher(Ficedula strophiata),the species with the most prominent altitudinal migration behavior,initiated upward migration at a temperature of 11-12℃ at 1800 m and initiated downward migration at a temperature of 12-13℃ at 3000 m.Besides,humidity was positively correlated with the DNI.Therefore,increasing humidity(equals to increasing rainfall or snow) possibly caused downward migration of birds(DNI increased) and vice versa.Furthermore,bird species exhibiting a typical altitudinal migration behavior pattern are feeding on insects.Thus,the spatial and temporal changes of the invertebrate biomass might be an important ecological driver for the altitudinal migration of invertivorous(birds eating invertebrates) birds.This study provides fundamental data for the altitudinal migration of birds in the Hengduan Mountains and shows how altitudinal migration is seasonally dynamic across an elevational gradient in a subtropical mountain region.

Ecological traits affect the seasonal migration patterns of breeding birds along a subtropical altitudinal gradient

Altitudinal bird migration involves seasonal shifts up and down the altitude gradient annually.Asia as the place with the largest number of altitudinal migrants,has quite few related studies,especially for montane and temperate avifaunas.To explore the potential drivers of seasonal altitudinal migration for birds in the middle of Hengduan Mountains,we conducted a three-year investigation on breeding and non-breeding season bird communities at eight elevational bands(1200–4200 m)in the Gongga Mountains.We examined the altitudinal migration patterns and relationships between seasonal distribution shifts and species'traits of 50 species with sufficient data recorded in both seasons.We found that a large proportion of breeding birds underwent altitudinal migration and showed three migration patterns(downslope shift,upslope shift,no shift).Seasonal distribution shifts were mainly correlated with certain ecological traits.Species breeding at high and mid-elevations,nesting in scrub and being omnivorous are more likely to show downslope movements during the non-breeding season.In addition,territorially weaker species exhibited more diverse migration patterns.Notably,we found the hand-wing index(HWI)was actually more convincing than body mass in explaining altitudinal migration.These results consolidate the studies of seasonal altitudinal migration in montane birds.Our study could be used to bridge existing knowledge gaps that currently impeding effective conservation for montane avifaunas in the Hengduan Mountains.

Promoting polysulfide conversions via cobalt single-atom catalyst for fast and durable lithium-sulfur batteries

Although promising strategies have been developed to resolve the critical drawbacks of lithium-sulfur(Li-S)batteries,the intractable issues including undesirable shuttling of polysulfides and sluggish redox reaction kinetics have still been unresolved thoroughly.Herein,a cobalt single-atom(CoSA)catalyst comprising of atomic Co distributed homogeneously within nitrogen(N)-doped porous carbon(Co-NPC)nanosphere is constructed and utilized as a separator coating in Li-S batteries.The Co-NPC exposes abundant active sites participating in sulfur redox reactions,and remarkable catalytic activity boosting the rapid polysulfide conversions.As a result,Li-S batteries with Co-NPC coating layer realize significantly enhanced specific capacity(1295 mAh·g^(-1)at 0.2 C),rate capability(753 mAh·g^(-1)at 3.0 C),and long-life cyclic stability(601 mAh·g^(-1)after 500 cycles at 1.0 C).Increasing the areal sulfur loading to 6.2 mg·cm^(-2),an extremely high areal capacity of 7.92 mAh·cm^(-2)is achieved.Further in situ X-ray diffraction,density functional theory calculations,and secondary ion mass spectrometry confirm the high catalytic capability of CoSA towards reversible polysulfide conversion.This study supplies new insights for adopting single-atom catalyst to upgrade the electrochemical performance of Li-S batteries.