Study On The Vertical Spatial Differentiation Of Settlements In The Upper Reaches Of Minjiang River

Building livable,business-friendly,and beautiful rural areas is an important goal to improve the living environment in rural areas.Located in the upper reaches of the Minjiang River in western Sichuan Province,it is one of the core areas of ecological security in China and also a gathering place for ethnic minorities such as the Tibetan,Qiang,and Hui ethnic groups.The vertical gradient of the local landscape changes significantly,and ecological disasters occur frequently.The terrain,river distribution,and human activity factors have a great impact on the distribution of settlements and production environment.There are significant differences in the living environment of settlements within the region,which further exacerbates the fragmented spatial structure,chaotic functional use,disorderly development,hollowing out,and destruction of local settlements.Based on 2018 image data,30 m resolution DEM data,GIS platform and Fragstats4.2software,this paper divides 2935 settlement clusters in the upper reaches of Minjiang River into 5 types of settlements by referring to the vertical gradient differentiation characteristics of the upper reaches of Minjiang River,and uses GIS spatial analysis,landscape pattern index,geographical detector model analysis and other methods to analyze the spatial layout characteristics of settlements from the vertical and horizontal scales,Identify the types of influencing factors in settlements,explore the influence of each factor,and obtain the following vertical spatial differentiation patterns of settlements in the upper reaches of the Minjiang River:(1)According to the classification standards of mountain types in Sichuan,the settlements in the upper reaches of the Minjiang River are divided into five types of settlements: low mountain settlements,medium low mountain settlements,Zhongshan settlements,sub alpine settlements,and alpine settlements.Zhongshan has the largest number of settlements and the widest distribution basin,with the highest scale and level of low mountain settlements and the lowest number of high mountain settlements.The scale of five types of settlement clusters shows a positive correlation distribution in spatial distribution,with the highest correlation being low mountain settlements and the lowest correlation being Zhongshan settlements.Low mountain settlements present a concentrated distribution in the downstream of the main stream of the Minjiang River.High mountain settlements are clustered and distributed in the Heishui River basin,with the smallest density and scale of settlements.(2)The settlements in the upper reaches of the Minjiang River are classified into three types:clustered,striped,and scattered.There are significant differences in landscape shape indices among different settlement types,distributed in Zhongshan and subalpine settlements in the Heishui River basin,with high LSI values.These two types of settlements have the most complex and fragmented landscapes in the basin.The LSI value of the high mountain settlements distributed in the Zagunao River Basin is the lowest,indicating that the landscape of the settlement is the simplest and the morphology is the most regular;There is not much difference in connectivity and stability between various types of settlements.The highest connectivity is found in the middle section of the Minjiang River basin,while the lowest connectivity is found in the middle and low mountain settlements where the Shouxi River basin is located;The separation index between settlements varies greatly and the degree of fragmentation is high.The highest degree of fragmentation is found in the Zhongshan settlement located in the Heishui River Basin,while the lowest degree of fragmentation is found in the low mountain settlement located in the Yuzixi River Basin.(3)The scale of settlements is influenced by factors such as elevation,road network density,GDP,precipitation,distance from water sources,distance from arable land,population density,and temperature.The most influential factors are elevation,distance from water sources,road network density,and GDP,while the least influential factors are slope,aspect,and relative humidity.Among them,low mountain settlements are mainly affected by the synergistic effects of elevation,road network density,and GDP,while medium to low mountain and Zhongshan settlements mainly rely on the influence of precipitation and GDP.The scale development of sub high mountain settlements is mainly...