Habitat Conservation Strategy Optimization Of Lesser White-fronted Goose In The Middle And Lower Reaches Of The Yangtze River Based On Marxan And Portfolio Approach Under Climate Change

Climate change will change habitat quality and affect biodiversity indirectly.Lesser Whitefronted Goose,as an endangered migratory bird,is quite significant to biodiversity conservation in the middle and lower reaches of the Yangtze River.In this study,Maxent model was used to analyze the habitat suitability of the wild goose in four typical climate scenarios,combining with the distribution data and the typical environmental characteristics of the wild geese from 2004 to 2015.The results showed that: 1.The area value under the operating characteristic curve of all model subjects was high(AUC was higher than 0.8 in present and future scenarios,which showed that the model was highly predictive.)of all the environmental variables,the most influential variables were: habitat suitability index of Carex heterolepis,Alopecurus aequalis and Eleocharis migoana,average annual temperature,the coldest season mean temperature and the coldest monthly precipitation.The suitable habitat of the wild goose is mainly distributed in the middle and lower reaches of the Yangtze River in Hunan,the Yangtze River Delta region,especially in the East Dongting Lake region of Hunan Province.The prediction of the Maxent model of Shengjin Lake region in Anhui Province also explained the habitat suitability of the wild goose under different climate scenarios.In 2070,under the condition of RCP 4.5 climate emissions,the suitable habitat distribution range of the small white goose showed a significant shrinking trend.The average habitat suitability decreased from 5.1% to 3.00%.Based on the current climate and future climate scenarios,climate change has a great impact on the habitat suitability of wild geese.Therefore,the uncertainty of climate change will affect the conservation results of small white goose.Then,the suitable habitat of the wild goose was screened by running Marxan,and the selection frequency of each planning unit in the study area was obtained.A series of locations is obtained as the optimal solution.The selection frequency of the planning unit indicates the importance of the protection of a planning unit.The optimal solution is an ideal range for setting up a reserve for Lesser White-fronted Goose.The study shows that the optimal solution has 1104 planning units,mainly distributed in Hunan and the Yangtze River Delta region,among which the typical ones are: Dongting Lake region.The Shengjin Lake region and Poyang Lake region.In the establishment of nature reserves,the main funds invested in these areas will improve the conservation efficiency of the small white goose.Finally,by using the modern portfolio theory,the investment-risk efficiency curve of the studied region is obtained.The method is to distribute the resources in different proportions in Hunan,Jiangxi and the Yangtze River Delta region,according to the investment-risk efficiency curve.The risk and return of investment will be completely different.The study shows that if all the funds are invested in Hunan region,the risk caused by the uncertainty of climate change will reach the maximum,and the benefit of protection will also reach the maximum.If funds are allocated in proportion to the three regions of Hunan,the Yangtze River Delta,and Jiangxi,the risk of climate change uncertainty will be minimal,and the benefits of protection will be lower.Policymakers can weigh the risks and benefits according to the actual situation.Select the appropriate protection strategy.The method of this study was used to evaluate the habitat quality distribution of the Lesser White-fronted Goose,and to select a better investment area and investment ratio under the future conditions.It can be used as a reference for the optimization of bird habitat protection in the middle and lower reaches of the Yangtze River and the establishment of corresponding species protection strategies.