Delimitation And Control Of Urban Development Boundary In Central Urban Area Of Lueyang County Based On Ecological Security

With the rapid development of social economy,urbanization has rapidly expanded the scale of construction land and continuously eroded regional ecological space,resulting in the reduction of ecosystem types and fragmentation of distribution,In this context,the state has established a territorial spatial planning system,clearly delineated the control boundary of urban development boundary,and the natural environment is highly sensitive.With the development of economy and industry,the scale demand of urban construction land is increasing,the ecological security is threatened,and the demarcation of urban development boundary is imminent.Secondly,the central urban area of Lueyang County has special topography and landforms,the three rivers meet and the five mountains are surrounded,and the demarcation of the boundary is also facing multiple complexity.The current ’ double evaluation’ evaluation method is too universal and not targeted.Therefore,this study selects the perspective of ecological security to explore the method of urban development boundary demarcation in the central urban area of Lueyang County.Firstly,this paper investigates the regional natural situation and the characteristics of urban construction land expansion in the central area of Lueyang County,and obtains the potential driving factors affecting the change of urban construction land.Secondly,from the perspective of ecological security,combined with the natural ecological characteristics of Lueyang County,the ecological security space evaluation model is constructed,the ecological security space level of the study area is divided,and the ecological security characteristics of the study area are analyzed.Therefore,the ecological security index and the driving factor index of urban construction land are established,and the correlation analysis is carried out with the scale of urban construction land change respectively.The contribution degree of each factor to the change of urban construction land is obtained,and the mechanism of each factor and the change of urban construction land is analyzed.The internal and external mechanisms of the urban development boundary in the central urban area of Lueyang County-the external constraint mechanism under ecological security and the internal driving mechanism of urban construction land are obtained.Based on the above analysis,the delineation method of the development boundary of the central urban area of Lueyang County is proved : the comprehensive method combining the bottom line constraint and demand orientation is used to combined with the restrictive factors of urban construction,the rigid boundary of urban development in the central urban area of Lueyang County is preliminarily delineated.According to the contribution of each factor to the change of urban construction land,the weight distribution results of each factor are obtained,and the PLUS model is used to simulate the scale of urban construction land in the central urban area of Lueyang County in 2035 under different scenarios,and the discontinuous broken patches are removed to delineate the urban elastic development boundary.Finally,the rigid boundary and the elastic boundary are superimposed,and the centralized construction area,the elastic development area and the special purpose area are divided,and the corresponding control suggestions are put forward.The results show that :(1)The urban form of Lueyang County gradually spreads from point and block aggregation to the periphery,and then transitions to leapfrog expansion.Constrained by natural conditions,land use is tight,and the northern part and western part of the urban area is the fastest and strongest expansion area.(2)The overall ecological security situation of Lueyang County is good,but the high value area of ecological security is highly fragmented,mainly distributed in the south and north of the study area.(3)The urban development boundary is constrained by ecological security externally,while it is driven by urban construction land factors internally.The degree of influence of driving force from large to small is as follows :distance from secondary road,elevation,distance from river,population,disaster point,precipitation,slope,distance from primary road,GDP,distance from tertiary road,temperature.(4)In 2035,the area covered by the rigid boundary in the central urban area of Lueyang County is 12.60 km~2,and the area covered by the elastic boundary is 10.23km~2.(5)The control content of the centralized construction area,the elastic development area and the special use area in the central urban area of Lueyang County is obtained.The rigid boundary strictly controls the increment,and the elastic boundary is dynamically adjusted according to the demand.