Research On The Territorial Space Ecological Restoration Strategies Of Mountainous Area Based On Ecological Security Pattern

Ecological restoration of territorial space is essential for coordinating ecological civilization construction and high-quality development in the new era.Establishing an ecological security pattern is an essential spatial optimization approach for the ecological restoration of national space.As the main front of ecological civilization construction in China,the county area is conducive to ensuring regional ecological security and promoting the coordinated development of the ecological environment and social economy by constructing ecological security pattern and researching territorial ecological restoration strategies.This research uses Yunxi County in the Qinling-Ba Mountains as the research object.Firstly,the characteristics of land use change in Yunxi County during 2000-2020 are analyzed,and the county’s ecological problems are further analyzed and diagnosed.Secondly,the ecological source area is identified comprehensively from four aspects:the value of the ecological service system,landscape connectivity,habitat quality and natural protected area.The least resistance model and the circuit theory determine the ecological corridor and node.The ecological security pattern of Yunxi County is constructed and optimized through the urban expansion suitability analysis.Finally,based on the ecological security pattern and the field situation,Yunxi County is divided into ecological restoration zones,and critical projects are identified to put forward restoration strategies.The following conclusions are drawn through the research:(1)During 2000-2020,the land use quantity in Yunxi County was generally stable in structure,with woodland always having an absolute advantage,followed by cultivated land.Although the proportion of construction land is small,its dynamic attitude toward land use is the largest and changes are the most drastic.The conversion between forest land and other land types was the largest,accounting for 9.54%of the total land area.The distribution of land use change is mainly along roads and rivers.Chengguan Town has the highest comprehensive land use dynamic attitude,which is the hot area of construction land inflow.The hot spots of forest land inflow were mainly distributed in the northern part of the county and the junction of Shaanxi Province.In contrast,the hot spots of cultivated land inflow were distributed in Shangjin,Ma’an and other towns.Overall,landscape agglomeration degree and Shannon diversity index increased,indicating a good development trend of ecological level.From the single landscape index of construction land,patch density and maximum patch index increased,and single landscape fragmentation increased.The spatio-temporal evolution of land use comprehensively reflects the problems in the distribution and development of county construction land and poses threats to the ecological environment.(2)By giving consideration to the spatial structure,ecological function and practical management characteristics of the ecological source area,a total of 11 Yunxi ecological source areas,covering an area of 1415.24km~2,were identified,with woodland land accounting for more than 97%of the source area.The source areas were distributed in all regions except the southeast.Five ecological source areas were identified as important ecological source areas according to the size of landscape connectivity.The distribution of resistance surface is high in the west and low in the east,which is closely related to the terrain of Yunxi County.Ecological corridors total 1,180.30 km,of which 23 main corridors and 32 secondary corridors are distributed in the southern region,which is conducive to species migration.There are 130ecological nodes,and the distribution is more in the south and less in the north.In the suitability zoning of urban expansion,the conflict area between suitable expansion area and ecological source area accounted for 19.30%of the total area of ecological source area.According to the distribution of various ecological factors and the conflict with the suitability of urban expansion,the ecological source area and corridor are optimized and reorganized,and natural water system is added to form an ecological security pattern of"three districts,three corridors,one area and more points"in Yunxi County,so as to provide reference for the territorial ecological restoration of Yunxi County.(3)Yunxi County has been delimited as three-level territorial ecological restoration zoning.The first-level zoning is divided into three zones based on landform and river basin:Xianhe River Basin in the western mountain,Qianqian River Basin in the central mountain-valley and Tianhe River Basin in the eastern hill-valley.Five secondary zones were designated according to the distribution of ecological source,grain yield,water and soil conservation and water and soil conservation.Based on the field survey results and ecological nodes,the three-level zones are divided into key restoration areas,general restoration areas and ecological conservation areas.We will further identify 11 abandoned mines,three river basins and two key projects for comprehensive improvement of the whole territory.