| Giant panda(Ailuropoda melanoleuca)is the flagship species of animal protection in China.Under the protection policy of more than 50 years,the number of wild populations has reached 1387,and the habitat area has been restored.With the help of artificial breeding technology,captive giant pandas have formed a healthy and sustainable population.However,it cannot be ignored that the wild population of giant pandas still face the problems of habitat fragmentation and low natural reproduction rate.With sufficient captive populations,wild release has become an important way to solve these problems.Therefore,it is urgent to make a macro plan for the overall design of the target number and cycle of wild release.Canine distemper(CD)is a highly contagious and fatal disease,it has been proved to infect captivebred and wild giant pandas.Over the years,there have been many cases of giant pandas dying from canine distemper,and its potential threat cannot be ignored.This thesis first takes the giant panda habitat in Sichuan Province as the research object,based on the Maximum Entropy model(Maximum Entropy model,MaxEnt model)to construct an optimization method for finely predicting species distribution/disease risk.Secondly,combining the least cost path method(LCP)to explore the connectivity between patchy habitats,based on the home range and net reproduction rate of wild pandas,to estimate the maximum usable area of giant pandas in Sichuan Province under realistic conditions and their release targets.Subsequently,based on the positive points of domestic dog CDV detection and the distribution points of wild animals susceptible to CD,a risk model of CD in Sichuan Province was constructed;and the concept and indicators of niche overlap were introduced to comprehensively assess the CD risk and giant pandas wild release target under realistic conditions based on the region and the risk value.Finally,using the latest giant panda distribution data and a new generation of future meteorological data,based on two ages,three shared socioeconomic paths,and five climate simulations of climate change;construct a habitat model for giant pandas under the background of climate change and estimate wild release targets;build a risk model for CD under the background of climate change,and analyze the impact of CD risk on giant panda wild release.The main findings are as follows:1.Based on realistic conditions,the wild giant panda habitat in Sichuan is predicted to be 18,342 km2,with a maximum usable area of about 25053 km2,covering the central part of Sichuan Province in a strip shape,and the fragmented habitats are scattered in the north,northwest and south of the strip habitat.Under ideal conditions without major changes in the habitat environment,the 4th generation(approximately 50 years)should be used as the rejuvenation cycle of wild giant pandas in Sichuan Province,during which the annual release target is 9?20 per year.2.Based on the realistic conditions,the total area of CD high-risk area in Sichuan Province is 65301 km2,and the risk of CD is higher for giant pandas.The safe habitat available for giant pandas is extremely small(approximately 181 km2),which has greatly affected the living space of existing wild populations.The risk of disease should be prevented and controlled before wild release.3.The maximum usable area of giant pandas under climate change is lower than that based on realistic conditions,but it shows an upward trend with time.The release target to rejuvenation is 6?18 animals/year in the next 50 years,which is slightly lower than it in under realistic conditions.4.The area of CD high-risk area under climate change is lower than the area based on the realistic conditions,and it is showing a downward trend with age.The risk of canine distemper for giant pandas in Sichuan is extremely high:SSP126(extremely high risk)>SSP370(high risk)>SSP585(high risk);the risk from 2011 to 2040s>the risk from 2041 to 2070s.Under climate change,the safe habitat available for giant pandas is extremely limited,and CD risks should be effectively prevented and controlled before wild release.Based on the results of this study,the giant panda wild release targets under realistic conditions and climate change backgrounds are closer,but the risk of canine distemper has a great impact on giant pandas.Therefore,we suggest that we should improve our understanding of canine distemper risk on giant pandas,strengthen immunity to susceptible species,consolidate the surveillance system for epidemic disease,and carry out wild release of giant pandas under the premise that the canine distemper risk is effectively controlled. |
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