| Giant panda is the flagship species of biodiversity conservation in the world.The current number of wild animals in Sichuan Province is only 1,387,accounting for 74.4%of the total number of people in the country.It is one of the most precious and endangered species.However,canine distemper virus is an important new infectious disease that poses a serious threat to the healthy survival of wild pandas.First,this study used principal component analysis and maximum entropy model to explore the relationship between the spatial distribution of CDV and various environmental factors and the potential risk of CDV in the habitat of giant pandas.Secondly,using the environmental data for each year for five years between 1979 and 2013,and four Representative Concentration Pathways under BCC-CSM1-1,CCSM4,GISS-E2-R,HadGEM2-ES and MIROC5,to analyze and predict the future risks within the habitat of giant pandas.The center of gravity method was used to analyze the spatial changes of the center of high risk of CDV.Finally,we studied and analyzed the homology between the canine distemper of giant pandas and other different genotypes and different hosts with constructing the Phylogenetic tree.The study found that:firstly,Annual Mean Temperature(Bio 1,29.6%),Precipitation of Wettest Month(Bio 13,20.2%),Altitude(9.4%),Mean Diurnal Range(Bio 2,7.5%),December precipitation(Prec 12,7.1%)and Isothermality(Bio 33.7%)are the most important environmental variables affecting the spatial distribution of CDV,the most suitable range is 7.5～10 ℃,100～150 mm,<300 m,11～12 ℃,60～90 mm and 25～30 respectively.Secondly,the risk of CDV in the giant panda habitat presents a trend of increasing risk intensity from west to east.The CDV risk grades in Qinling,Laoshan,Laoshan and Daxianglingshan areas are high,and the CDV risk in Liangshan and Xiaoxianglingshan areas is high.The risk is at a low risk level.At the same time,less than 5%of the panda sample sites are within the low-risk area of CDV,and more than 95%of the sampling sites are within the high-and medium-risk areas.The number of high-level and middle-level sites is basically similar.The overall risk level in the giant panda habitat is high.Thirdly,from 1979 to 2013,the center of high-risk CDVs in giant panda habitats presented a tendency to migrate from the northeast to the southwest,that is,the risk intensity in the southeast region of the habitats showed an overall increase.In the five global climate models,the overall 2050s and 2070s risk intensity predicted by the BCC-CSM1－I and CCSM4 models is lower than contemporary,and the high-risk area is smaller than contemporary,and its calculated high-risk center of gravity lies in the east of Ya’an City and Meishan.At the junction of the city,there is a tendency to migrate southwards.While the GSS-E2-R,HadGEM2-ES,and MIROC5 models predict an overall higher risk intensity of 2050s and 2070s than contemporary ones,and the high-risk area is larger than contemporary,while the calculated high-risk center of gravity also focuses on the junction of eastern Ya’an City and Meishan City.In the area,there is a tendency to migrate to the south or southwest.Fourth,the canine distemper virus strains of giant pandas are genetically evolved to be the Asia-1 genotype,and among 14 different genotype strains,the canine distemper of the Asia-1 gene is the greatest threat to Chinese giant pandas.Therefore,this study aims to carry out risk prevention for the distribution of CDV in the typical distribution area of giant pandas.It not only promotes the prevention and control of public health diseases and public health safety,but also has a theoretical basis for the protection of giant pandas and the world’s biodiversity.This will obtain a wide range of political,economic and social benefits. |
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