Fragmentation Characteristics And Landscape Ecological Risk Assessment Of Hooded Crane In Breeding And Overwintering Habitats

Ecological risk assessment is an important theoretical basis for the formulation of current regional land use structure optimization,scientific management of land resources and ecological protection.Xinqing Wetland was one of the important breeding habitats of Hooded Crane in Xiaoxing'anling,China.Shengjin Lake Wetland was one of the most important wintering habitats of rare species of Hooded Crane in the middle and lower reaches of the Yangtze River in China.However,in recent years,with the continuous development of the economy and the acceleration of urbanization,the irrational land use status of occupied wetlands have been appearing,such as resettlement relocation and agricultural production.The structure of wetland ecosystem,and the population of the Hooded Crane were damaged seriously.Simultaneously,breeding and wintering habitats of the Hooded Crane were destroyed.This paper uses the TM image data and land use coverage data of 1986,1995,2008 and 2018 of Xinqing Wetland and Shengjin Lake Wetland as data sources.Remote sensing and geographic information technology were used to study the landscape of the study area.The changes were analyzed to determine the main breeding and wintering habitat types of the Hooded Crane population,and the habitat fragmentation characteristics were analyzed.Finally,the ecological risk index of habitat landscape was constructed to evaluate the changes of landscape ecological risk in the study area,and scientific countermeasures and suggestions were proposed for the protection of the breeding and wintering habitats of Hooded Crane and the population of Hooded Cranes.The main conclusions of the study were as follows:1)Referring to the relevant literature on landscape classification,combined with the actual situation of Xinqing Wetland and Shengjin Lake Wetland.The landscape types in the study area were divided into 8 categories:dryland,forest,waters,paddy fields,construction land,reed shoal,marsh land and mudflats.ArcGIS 10.2 and FRAGSTATS 4.2 software were used to obtain the landscape information of the Xinqing Wetland and Shengjin Lake Wetland.2)The changes of the landscape types,landscape dynamics and landscape transfer matrix of the eight types of land in the study area were analyzed.In 1986,the dominant landscape of Xinqing Wetland was forest and mudflats,accounting for 61.17%and 13.03%respectively.The main landscape in 2018 was forest and reed shoal,accounting for 55.94%and 16.10%respectively.From 1986 to 2018,the area of reed shoal,dryland,paddy fields,construction land and waters increased,and the area of mudflats,forest and marsh land showed a general decrease.In 1986,the dominant land types of the Shengjin Lake wetland were dryland,forest and waters,accounting for 30.59%,18.49%,and 16.06%,respectively.In 2018,waters and paddy fields were the main landscapes,accounting for 26.75%and 14.49%.From 1986 to 2018,the area of waters,paddy fields,construction land,marsh land and mudflats increased,and the area of dryland,forest and reed shoal showed a decreasing trend.3)Through Pearson correlation analysis,referring to the relevant literature of Hooded Crane,combined with the relevant data and actual investigation results provided by the Protected Area Authority,the main types of breeding habitats of Hooded Crane in Xinqing Wetland are forest,waters,paddy fields,reed shoal and marsh land.The main types of wintering habitats of Hooded Crane in Shengjin Lake Wetland are waters,paddy fields,reed shoal,marsh land and mudflats.These habitats provide a rich source of food,a hidden environment for rest and overnight accommodation for the survival and reproduction of the Hooded Crane.During the breeding season and wintering period,the Hooded Crane often inhabits mudflats and marshes close to the waters.The main difference is that Hooded Crane prefer to breed in hidden forest wetlands.The fragmentation of the Hooded Crane habitat in the Xinqing Wetland and the Shengjin Lake Wetland in 1986,1995,2008 and 2018 was analyzed from the landscape level and the plaque type level,and the degree of habitat fragmentation was found to be serious.4)The landscape ecological risk assessment model was constructed by the landscape pattern index method,and the ecological risk in the study area was divided into five levels:extremely low ecological risk,low ecological risk,medium ecological risk,high ecological risk and extremely high ecological risk.The landscape ecological risk of the study area was analyzed from the aspects of single landscape type,spatial distribution characteristics and time series changes.Overall,from 1986 to 2018,the landscape ecological risks of Xinqing Wetland and Shengjin Lake Wetland all showed an upward trend,both from the low ecological risk level in 1986 to the middle ecological risk level in 2018,The ecological risk value of Xinqing Wetland increased from 0.3777 in 1986 to 0.5882 in 2018;the ecological risk value of Shengjin Lake wetland landscape increased from 0.2706 in 1986 to 0.5709 in 2018.