Study On The Natural Habitat Of Wild Giant Salamande

The Chinese giant salamander(Andrias davidianus)(CGS)is a Class II protected animal and an International Union for Conservation of Nature critically endangered species.The animal numbers have been drastically reduced by habitat loss and fragmentation due to human fishing and environmental changes.Thus,conservation research on CGS is urgently needed.In this study,based on the collection,collation and excavation of environmental data of major CGS habitats in China,we firstly selected Qinzhou Rare Aquatic Wildlife National Nature Reserve in Gansu Province,where there is a lack of basic data on CGS habitats research,to investigate,analyse and evaluate the natural habitat of CGS.Secondly,we selected the natural habitat of CGS in Hunan Province,where human interference is relatively high,and used questionnaires to obtain the current knowledge and conservation attitudes of residents around the natural habitat,and to analyse their interrelationships and influencing factors.Finally,using the previously collected and collated data on the distribution loci of CGS,supplemented by the current research in Gansu and Hunan Provinces,and combined with the environmental factor data in the database,a Max Ent model was constructed to predict the distribution and trends of wild CGS habitats.This study not only complements the environmental and human data on the natural habitat of wild CGS,but also provides a more comprehensive understanding of the survival status of CGSs and predicts the future distribution of suitable natural habitats for CGS,providing a theoretical reference for the conservation and release activity of CGS.The main findings of the study are as follows:(1)In this study,water quality parameters,fish and benthic macrofauna in the natural habitat of CGS in Qinzhou Rare Aquatic Wildlife National Nature Reserve in Gansu Province were investigated and analysed in the field.The results showed that:the chemical oxygen demand,total nitrogen,mercury and sulphide met Class III surface water standards(GB3838-2002),total phosphorus,chromium(hexavalent),total coliform and ammonia nitrogen met Class II surface water standards,the rest of the indicators met Class I surface water standards,and all water quality parameters met fishery water quality standards(GB11607-89).In addition,we found that benthic macrofauna diversity was low,with a total of 37 taxonomic units identified,and aquatic insects were the absolute dominant species,with an average of 9 species at each sampling site,and only 3 species at sampling sites S1 and S7,but there were species with low water pollution tolerance,and the overall biological evaluation indicated a relatively healthy water quality.A total of 5 species of fish were collected,all of which were small fish,and the amount of small fish resources in the CGS area of the reserve was estimated to be 1.4×10~5 kg by fish catch.The protected area can support 25,299 wild CGSs according to the estimated fish catch.(2)The results of a questionnaire survey of residents around the main distribution areas of CGS in Hunan Province showed that:more than 99%of local residents were aware of the species and had positive attitudes towards conservation,although their knowledge of CGS conservation laws was low.Their knowledge of CGS and related laws was significantly and positively correlated with their conservation attitudes(P<0.05),and their exposure to CGS was significantly and positively correlated with their conservation attitudes(P<0.05),and differed significantly between genders and places of residence(P<0.05),with males being more aware of,more exposed to and more willing to protect about CGS than females.There were significant differences in exposure to CGS by age(p<0.05),with older respondents being more likely to be exposed to CGS than younger respondents.(3)A Max Ent model was constructed based on 186 high-precision wild CGS distribution loci.The resulting model AUC value was 0.963,with excellent prediction results and high confidence.The prediction results showed that:the total area of suitable habitat for existing CGS in China to be 7.67×10~5 km~2,and the main limiting factors and optimum range for habitat selection are the Bio4(750.91–849.60),PD(<201 people/km~2),Bio6(–4.33 to 2.79℃),Bio12(980.72–1537.35 mm)and Alt(314.50–850.76 m).Under the two emission scenarios(SSP126 and SSP585)in 2050and 2070,the suitable area of CGS will decrease sharply by 31–58%compared to the current distribution,with a southwestward migration trend.(4)As mentioned above,the habitat quality of some existing CGS habitats is relatively good.However,the habitat survey should be comprehensive and long-term,and the impact of human influence on the conservation of CGS should be taken into account,and the initiative of the public,especially the local residents of the CGS habitat,should be fully utilized.Therefore,the habitat data of the natural habitat of the CGS will continue to be improved in future studies.At the same time,there is a need to plan ahead for the artificial maintenance of the natural habitat of the CGS or the conservation of the CGS in ex situ in order to cope with the decline and change of suitable habitat for the CGS in the future.