Study On Habitat Fragmentation Evaluation And Corridor Construction Of Wolong Giant Panda

The giant panda(Ailuropoda melanoleuca)is a rare and precious species of China’s national treasures and is a precious natural resource shared by humans.Wolong Nature Reserve,as the largest nature reserve of giant pandas in Sichuan Province,has 10% of the country’s largest population of giant pandas.This paper selects Wolong Nature Reserve as a research area,evaluates the fragmentation changes of giant pandas after the Wenchuan earthquake in 2008,and proposes a scheme for constructing corridors in protected areas based on the results of fragmentation.The main research contents and results of this article are as follows:(1)In order to obtain land cover classification data,this paper uses Landsat image data as a data source,applies ENVI to preprocess it,and evaluates the accuracy of the processing results.Including atmospheric correction,geometric fine correction,splicing and cutting,supervised classification and so on.This paper uses the maximum likelihood classification method to classify land cover types in protected areas into five categories: forest land,grassland,water area,bare land and snow,and uses the confusion matrix and Kappa coefficient to verify its classification accuracy.The overall accuracy is respectively 91.52%,86.46% and 88.88%,Kappa coefficient were 0.8759,0.8216 and 0.8349 respectively.(2)The landscape pattern parameters were selected from the three levels of plaque,type,and landscape to evaluate the fragmentation of the habitat structure of giant pandas in the Wolong Nature Reserve after the earthquake.Firstly,from the aspect of the basic characteristics of plaque,the number of patches(NP)in forest land,grassland,and bare land decreased year by year,while the water area remained basically unchanged;in patch type area(CA),the area of forest land increased year by year.From 963km2 in 2009 to 1066km2 in 2016,the total area increased by more than 100km2,the restoration of forest land was good,and the grassland and bare land area showed a declining trend year by year,from 179km2 in 2013 to 599km2 in 2013 and 96km2 in 2016.The largest patch index(LPI)in forest land has increased year by year.They were 30.76%,49.78%,and 49.98%,respectively,and the PLANDs of the forest land were 0.47,0.51,and 0.52,respectively.It can be seen that the forest lands are the main habitat landscapes in the reserve,and they are also habitats for giant pandas to survive.Secondly,at the type level,this paper takes advantage of landscape shape index(LSI),shape index(SHAPE),similar proximity proportionality(PLADJ),aggregation index(AI),spread index(CONTAG),and edge density(ED).The degree of fragmentation and reasons of the five types of ground features in the protected area were analyzed by the CONNECT index.The conclusion was that the fragmentation decreased year by year,but the fragmentation factors of different landscapes were different.The forest land was used as the habitat of giant pandas.The fragmentation of the main landscape types is mainly caused by the division of other landscape types,while the fragmentation of other landscapes is mainly characterized by scattered distribution,a small number of plaques in large areas,and the complex shapes of plaques.At the landscape level,the Fragrance Diversity Index(SHDI),Shannon Uniformity Index(SHEI),Simpson Diversity Index(SIDI)and Simpson Evenness Index(SIEI)were selected to evaluate the fragmentation of the entire habitat of the protected area.Different kinds of elements have different dominating powers for the overall landscape composition,among which woodland occupies a dominant position,while other types of discretely distributed landscapes are the main factors causing fragmentation.(3)Designed four habitat corridor programs suitable for the migration of giant pandas.By reading a large number of references,the author has in-depth analysis of habitat factors that are suitable for the survival of giant pandas,extracted 4 “sources” of giant pandas,selected natural environment factors such as altitude,slope,water source,biological and environmental factors of the staple food bamboo and forest types,and human Six habitat factors,such as the road factor of the interference factor,were used as building factors for the migration resistance grid of giant pandas.According to the habitat selection of giant pandas,the resistance of each factor was ranked separately,and the weight of each factor was determined using the analytic hierarchy process,which was 0.0751,respectively.0.1032,0.1136,0.3339,0.2967,and 0.0775 were weighted and superimposed on the factors to construct a resistance grid.Finally,a cost-distance model was established to identify four habitat corridors suitable for migrating giant pandas.