Application of eDNA Metabarcoding for Detecting Anura in North China

eDNA metabarcoding is an advanced method formonitoring biodiversityproposed in recent years.By analyzing DNA in water,soil and sediment samples,the technology obtains species distribution and population quantity information.It was found that macrobarcode technology is more accurate than the traditional method in measuring the species richness of some groups.In Europe,America and South America,the relia bility of this technology in monitoring amphibian diversity in the wild was studied,and it was found to be better than traditional biodiversity monitoring methods in detecting species diversity.At present,amphibian monitoring mainly depends on various traditional methods,such as transects,drift fence traps,artificial shelters and mark-recapture.These monitoring techniques have many shortcomings,such as low accuracy and strong subjectivity of study results.These technologies have poor effects on rare,invasive and endangered species with strong concealment ability,low density and strong seasonality and are difficult to implement in sites inaccessible to people.Traditional monitoring technology also requires considerable investment of human and material resources,and the economic cost is relatively high,while eDNA metabarcoding ismore efficient and less costly,so it is important to use eDNA meta barcoding in amphibian monitoring in China.In this study,the eDNA meta barcoding and traditional line transect method(TLTM)were used to study the characteristics of the two methods in the Beijing-Tianjin-Hebeiregion.Repeated samplingwas conducted on 58 waterbodies in July 2019 and June 2020.After sequencing the samples using highthroughput sequencing technology,the differences between metabarcoding and commonly used TLTM surveys in detecting the diversity of four amphibians in North China were assessed.Our results showed that eDNA meta barcoding is more sensitive to the detection of the four amphibian species in the sampling area,and the combined use of eDNA metabarcoding and TLTM can improve the survey results of amphibians in the survey area to the greatest extent.In addition,in the process of species classification and identification of metabarcoding results,7 species of reptiles were detected,indicating that eDNA metabarcoding is also useful to detect reptiles.The results of this study indicate that metabarcoding in combination with TLTM can accurately estimate the diversityof amphibians in a short-term survey in North China and is also useful in reptile species detection.

Foraging Responses of the Larvae of Invasive Bullfrogs (Lithobates catesbeianus)： Possible Implications for Bullfrog Control and Ecological Impact in China

The predatory behavior of invasive species can affect their ecological impact, and offer opportunities for targeted control. In Australia, tadpoles of invasive cane toads （Rhinella marina） do not consume eggs of native anurans, but are strongly attracted to （and consume） newly-laid eggs of conspecifics; chemical cues from such eggs （or adult secretions） thus can be used to attract toad tadpoles to traps. Do other invasive anurans show similar selectivity？ Our laboratory trials on a Chinese population of invasive American bullfrogs （Lithobates catesbeianus） revealed similar behaviors as exhibited by Australian cane toads. Bullfrog tadpoles rarely consumed the eggs of native anurarts, but were attracted to both bullfrog eggs and bullfrog skin secretions. Although the attraction response was less intense in bullfrogs than in cane toads, it might nonetheless enable selective removal of bullfrog tadpoles from invaded sites.

Trace element and sulfur isotope compositions of pyrite from the Tianqiao Zn–Pb–Ag deposit in Guizhou province,SW China:implication for the origin of ore-forming fluids

The Tianqiao Zn–Pb–Ag deposit in SW China,hosted by Devonian and Carboniferous limestone and clay rocks,is composed of sulfides such as sphalerite,galena,and pyrite.Pyrite is present in different paragenetic stages and can be divided into four types based on textures and mineral assemblages.Pyrite from the adjacent Shanshulin deposit(Py-SSL)is also used for comparison.Py1 shows framboid texture with grain diameter up to 1 mm and was commonly replaced by sphalerite.Py2 is characterized by overgrowth texture and displays inner oscillatory zoning.Py2 is associated with abundant sphalerite and galena.Py3 shows replacement relics textures where galena fills the fractures of pyrite.Py4 is a euhedral to subhedral crystal disseminated in dolomite and is characterized by deformation and fragmentation textures.Minor sphalerite and galena are associated with Py4.Py-SSL is subhedral and disseminated in dolomite,similar to Py4.Py1 was formed by a diagenetic or sedimentary process,whereas Py2 and Py3 were formed by multiple stages of ore fluids.Py4 and Py-SSL were formed at the carbonate-sulfide stage,but Py4 suffered from deformation after its formation.Py1,Py2,and Py3 are characterized by relative enrichment of Sb,Cu,and As,in contrast to Py4 and Py-SSL with higher Cr,W,Ge,Sn,Tl,Ni,and Ga contents.However,critical metals such as Ge,Ga,and In in pyrite are generally lower than10 ppm,which are not economically important.The trace element variation in Tianqiao pyrite with paragenesis results from fluid evolution in the Pb–Zn ore system and competition with co-precipitating minerals.Diagenetic and ore-forming hydrothermal fluids are responsible for the formation of different types of pyrite.Ore-related pyrite from the Tianqiao and Shanshulin deposits has Co and Ni distribution features similar to pyrite from sedimentary pyrite and submarine hydrothermal vents,different from those in volcanogenic massive sulfide,iron oxide-copper–gold,and porphyry Cu deposits,indicating their derivation of relatively low-temperature(<~250°C)hydrothermal fluids,similar to basin brines or seawater.,via fluid-rock interaction.This conclusion is also supported by the sulfur isotope composition of sulfides which are 13.0–13.5%,and 15.6–20.5%for Tianqiao and Shanshulin deposits,respectively.

Phylogeny and Biogeography of Common Toad(Bufo bufo) in Xinjiang, China

The common toad, Bufo bufo(Linnaeus, 1758), is widely distributed in Europe and parts of Africa. Previous studies of the genetic relationships among B. bufo populations have not included Asian populations. Here, we investigated the phylogenetic relationships of B. bufo, including a population from Xinjiang, China, using 722 bp of the mitochondrial cytochrome b sequence and identified six subclades and 85 haplotypes in populations from 22 countries. Phylogenetic analyses and pedigree differentiation revealed that the subclade containing the Xinjiang population has undergone a relatively recent expansion. Combining our results with those of previous studies, we found that the common toad population of Xinjiang, China, belongs to the European-Caucasian lineage and that its closest relatives based on phylogenetic relationships were eastern European populations. Our research contributes to expanding knowledge of the geographic distribution of B. bufo and illuminates the lineage and genetic relationships of the B. bu fo population in Xinjiang, China. Future research should continue to update the geographic distribution of B. bufo and complete a genetic investigation of the full range of this species.