The rarity of limestone cave species due to habitat degradation makes them of special interest in conservation biology.The wild Chinese Giant Salamander Andrias davidianus,an evolutionarily distinct and globally endangered species,are nearly all obligate into living in inaccessible mountain caves now.We detected that only 14-29 breeders,with the effective population size of 9-25（5-44 of 95% confidence interval）,were in each of three caves,through genotyping 20 microsatellite loci on larvae that were flushed out of caves.Both heterzygosity excess and M（ratios of allele number to allele size range） tests indicated severe genetic bottlenecks among populations.Both mitochondrial,with only one or two haplotypes of D-loop region（770-771bp） in each population,and nuclear genetic structure showed clear divergence between populations.Considering the long life history,small population size,and genetic differentiationof the Chinese Giant Salamander,putting an end to poaching and recovering the karst ecosystem instead of releasing may be the sole measures to save this severely threated species.
Jie WANGHongxing ZHANGFeng XIEGang WEIJianping JIANG
Chinese giant salamander(CGS, Andrias davidianus) is experiencing the threat of extinction. It is disappearing gradually, because of overharvesting, environmental pollution, specially river pollution, activity of human exploitation, and so on. We conducted community interview fieldworks to collect respondent data from Xieba Country(not reserve) situated in Zhengan County of Guizhou Province, where one of the places known by historical giant salamander records in Guizhou. Through the analysis of the collected data, we created quantitative data of use for conservation management on the local status of salamander populations, and we compared our data with those available data of Y. Pan et al., who investigated the status of CGS in 3 reserves in Guizhou Province in 2015.The conclusions have a similar trend, which proved that the collected data were creditable. Through statistical analysis of the comparison data, the number of wild CGS decreased actually followed the increase of artificial framing.Because of the source of breeding to catch wild CGS, overharvesting was likely the most reason to make wild CGS decline.
13 water quality parameters were tested from 38 reaches of 34 counties in Guizhou where Chinese giant salamander(Andrias davidianus) distributed over the past 30 years. Dissolved oxygen and p H were found to be significant determinants of the species distribution in recent years(P<0.05). There was no Chinese giant salamander distribution in the recent five years in rivers with dissolved solids of greater than 415 mg/L, conductivity of greater than 639 us/cm, salinity of greater than 0.31 ppt and total hardness of greater than 150 mg/L. Sensitive to environment, the Chinese giant salamander is an important indicator for environmental quality, so it could be used as one of the environmental indicator. Eutrophication, chemical fertilizer, pesticides and inorganic pollutants may be one of reasons driving wild CGS into extinction.
