Research On Landscape Ecological Health Assessment And Optimization In Harbin Central District

Along with urbanization,the increasingly severe human disturbance has aggravated the operation risk of urban landscape ecosystem,and the ecological bottleneck has gradually become prominent.The National New Urbanization Plan(2021-2035)in 2021 proposed to accelerate the coordinated development of the urban ecological environment and social economy.The 20 th CPC National Congress pointed out to comprehensively promote the construction of Chinese modernization in which man and nature coexist harmoniously,and the coordinated and sustainable development of urban ecology has entered a new stage.Landscape ecological health is devoted to studying the health problems of landscape ecosystem which are seriously affected or degraded or even disappear under the interference of human activities.However,at present,the theoretical research and practice on landscape ecological health of urban are still immature,the scientific and systematic evaluation system is still lacking,and the driving influence law is unclear,which leads to the lack of guidance significance of the research results on the management and care of urban landscape resources,therefore,the research on assessment and optimization of urban landscape ecological health is of great significance for the high-quality development of urbanization.Based on landscape ecology,sustainable development science,urban landscape ecology,and other related theories,the research clarifies the connotation and criteria of urban landscape ecological health and constructs an integrated "pattern-process-function" urban landscape ecological health assessment system with a sustainable development orientation.Taking the central district of Harbin as the study area,we select six periods of remote sensing image data from 1981 to 2020,on the basis of investigating and analyzing the spatial-temporal changes of landscape ecological resources in the study area,a practical assessment of its landscape ecological health is carried out to explore its spatial-temporal evolution and spatial correlation characteristics,thoroughly study the drivers of landscape ecological health evolution and prediction of its future development trend,and finally,formulate a forward-looking landscape ecological health optimization method and put forward targeted suggestions.The main research results are as follows.(1)Through the methods of land transfer matrix,land use dynamic degree,center of gravity shift analysis,and landscape pattern index,it reveals the characteristics of land use and landscape pattern in the study area from land use change,the evolution of blue-green space and non-blue-green space,and landscape pattern evolution.The research finds that the land use in Harbin central district is profoundly affected by rapid urbanization,and the land use transfer tends to be complex,with the transformation rate gradually accelerated and the spatial distribution of the transfer more extensive.The landscape pattern changes significantly with increasing fragmentation and decreasing connectivity.(2)Interprets the criteria and characteristics of urban landscape ecological health based on the relevant theoretical basis,build a sustainable development-oriented "pattern-processfunction" integrated urban landscape ecological health assessment research framework,and select the assessment indexes through in-depth analysis of various connotations and complete the construction of the urban landscape ecological health assessment index system.The subjective and objective integrated assignment method of integrated hierarchical analysis and entropy weighting method constructs the assessment index weighting system.In addition,the classification scoring criteria of the Harbin central district landscape ecological assessment model are determined with reference to relevant research results.Finally,an easily quantifiable urban landscape ecological health assessment model is constructed,which is not only based on the assessment research of the health status of the landscape ecosystem itself but also emphasizes the sustainability,providing a new perspective for urban landscape ecological health assessment.(3)The moving window method,standard deviation ellipse analysis,and spatial autocorrelation analysis are applied to systematically analyze the spatial-temporal evolution and spatial correlation characteristics of landscape ecological health in the study area,and using incremental spatial autocorrelation to explore the clustering trends at different scales.The results show that the mean value of landscape ecological health in the study area from 1981 to2020 decreased from 0.481 to 0.446,from “medium” to “lower” level,showing a trend of increasing area of low level and medium level and decreasing area of high level.The spatial distribution of landscape ecological health is obviously influenced by landscape types,the spatial distribution pattern is "northwest-southeast" direction and shows a weakening and then strengthening trend,and the center of gravity gradually migrates to the northeast.Landscape ecological health has a stable spatial agglomeration phenomenon and gradually increases,the low value area experiences the spatial correlation characteristics of “overall agglomeration-overall agglomeration and local dispersion strengthening-overall agglomeration and multiple dispersion”,and the high value area experiences the spatial correlation characteristics of“multiple agglomeration and local dispersion-multiple agglomeration and local dispersion weakening-multiple agglomeration”.The landscape ecological health of the study area has the most significant clustering trend at the 2km scale,which can be the best scale for its analysis and optimization.(4)The driving mechanism of the urban landscape ecological health was clarified with reference to relevant research results,and a system of 14 driving factors including two categories of natural and human factors is constructed,and the geographic detector model is used to clarify the driving influences and their interactions and ecological factor detection that drive the evolution of the landscape ecological health in the study area at different stages.The analysis show that human factors are long-term drivers of the evolution of landscape ecological health in the study area,and the explanatory power of natural factors gradually decreases and that of human factors gradually increases during the study period.A small number of drivers do not significantly differ in the spatial distribution of landscape ecological health in the study area.The evolution of landscape ecological health in the study area is driven by a combination of factors,all of which are interactively enhanced,with a gradual shift from natural interactive effects to human interactive effects during the study period.(5)The prediction of landscape ecological health development trend can provide prospective data support for its optimization plan development,and the research makes a prediction of landscape ecological health in the study area in 2035 by coupling the ANN-CA model.On the premise of clarifying the objectives,principles,and optimization theories of landscape ecological health,according to the drivers of landscape ecological health in the study area,we comprehensively understand the relationship between landscape ecological pattern,function,and process,and develop a forward-looking method for optimizing landscape ecological health in the study area of “landscape ecological network construction” and“landscape ecological restoration zoning”.Combining the assessment and prediction results of the landscape ecological health of the study area,the minimum cumulative consumption resistance(MCR)model and complex network analysis are used to construct the landscape ecological network in the study area,and on the basis of "source-sink" landscape identification,ecological corridor extraction,ecological node identification and classification,ecological "source" and ecological corridor buffer zone setting,a landscape ecological health optimization model of "one ring,two vertical,three horizontal,multiple corridors and nine cores" is proposed.The quantitative analysis determines the extent of the negative impact of the "sink" landscape on the landscape ecological health of the study area,based on which the landscape ecological restoration area is delineated and restoration strategies are proposed.In addition,it further proposes the feasibility suggestions for optimizing the landscape ecological health of study areas at multiple scales and multiple levels.The research evaluates the landscape ecological health of Harbin central district,a typical urbanization area,and explores its optimization methods.Based on the relevant theoretical basis,a sustainable development-oriented ’ pattern-process-function ’ integrated landscape ecological health evaluation model is constructed,which further improves the theory and method of urban landscape ecological health evaluation.Using spatial analysis,regression analysis,ANN-CA coupling model and other technical methods,a forward-looking landscape ecological health optimization scheme is developed by integrating the evolution characteristics,driving factors and prediction simulation of landscape ecological health in the study area,which broadens the research ideas of urban landscape ecological health optimization.