Construction Of Spatial Pattern Of "Surface,Line And Point" Ecological Protection In Typical Loess Landform Area

As urbanization levels rise,the prominence of various ecological degradation issues increases,thereby directly or indirectly impacting regional ecological,economic sustainable development,and ecological security stability.The construction of a spatial pattern for ecological red lines and the proposition of suitable control and implementation strategies based on local conditions play a crucial role in safeguarding regional ecological security and ensuring the proper functioning of ecosystem services.The paper focuses on the typical loess landform area of Yan’an City and introduces a comprehensive ecological environment assessment model.By integrating the local ecological environment and conducting a quantitative evaluation and analysis of four key indicators of ecosystem service importance(water conservation,soil conservation,biodiversity maintenance,wind and sand fixation)and two indicators of ecological sensitivity(soil erosion sensitivity,land desertification sensitivity),the evaluation results are overlaid and analyzed using weightings determined by the entropy method.This process generates comprehensive assessment results for the ecological environment in Yan’an City.Using the cumulative percentage method,the research area is divided into three ecological protection zones:the core protection zone,key protection zone,and general protection zone.The"core protection zone"serves as the preliminary delineation for the ecological red lines.Subsequently,the results of the ecological red line delineation are overlaid with existing prohibited development areas and nature reserves to obtain a comprehensive delineation of the"surface"elements of the ecological red lines.Simultaneously,areas identified as highly important based on the comprehensive assessment of the ecological system’s functional importance and areas identified as non-sensitive based on the comprehensive assessment of ecological sensitivity are overlaid to identify ecological source areas.Using the Minimum Cumulative Resistance model(MCR),the"line"elements of ecological corridors are constructed,and corresponding ecological nodes(ecological barriers and ecological sensitive points)are identified.Finally,the paper establishes a"surface-line-point"ecological protection spatial pattern for Yan’an City.The research results indicate that:(1)The results of the weight allocation for ecosystem service importance reveal that biodiversity maintenance holds the highest weight.The assessment of ecosystem function importance in Yan’an City demonstrates a consistent increase in importance from north to south,displaying a spatial distribution pattern with lower importance in the north and higher importance in the south.In terms of quantity,there is a minor difference in the area covered by the three different levels of ecosystem service importance.Regarding the weight allocation for ecological sensitivity indicators,soil erosion sensitivity carries a greater weight than land desertification sensitivity.In spatial distribution,the levels of ecological sensitivity in Yan’an City exhibit a decreasing trend from north to south,presenting a spatial pattern with higher sensitivity in the north and lower sensitivity in the south.In terms of quantity,regions classified as having a general level of ecological sensitivity account for 16.74%of the area,predominantly located in the southern part of Yan’an City.Regions classified as having a moderate level of sensitivity are concentrated in the central and southern parts of Yan’an City,comprising approximately 47.52%of the area.Highly sensitive regions encompass 35.74%of the total area,primarily concentrated in the northern areas.(2)Overall,Yan’an City exhibits a distinct ecological distribution pattern,with the northern region being highly ecologically sensitive and the southern region characterized by extremely important ecosystem service functions.The general protection zone,key protection zone,and core protection zone cover areas of 206.11 km~2,21,179.44 km~2,and 15,857.2 km~2,respectively.The ecological red line area in Yan’an City encompasses a total area of 14,710.51 km~2,primarily concentrated in the southern part of the city with scattered patches in the central region.Although these patches are abundant,their sizes are relatively small.The lush vegetation cover in the Huanglong mountain,Lao mountain,and Ziwuling areas plays a crucial role in local climate regulation,water conservation,wind and sand fixation,soil conservation,and biodiversity maintenance,serving as the ecological security baseline for the region.In terms of overall distribution,Fuxian County has the largest proportion of the ecological red line area,followed by Yichuan County and Huangling County.(3)Yan’an City is characterized by a highly uneven spatial distribution of 33 ecological source patches.These patches are primarily concentrated in the southern region of the city,where the Huanglong mountain,Lao mountain,and Ziwuling areas play a significant role in ecological protection.Conversely,the northern region has a limited presence of ecological source patches,which corresponds to the lower quality of the local ecosystem environment.Yan’an City boasts a total of 80 ecological corridors,spanning a combined length of362.609 km.The longest ecological corridor stretches from Huanglong County to Huangling County,covering a distance of 13.347 km.(4)Yan’an City features 71 ecological nodes,including both ecological barriers and ecological sensitive points.Out of these,21 ecological barrier points are mainly situated at the intersections of major transportation routes,such as highways,national roads,and ecological corridors within Yan’an City.The remaining 50 ecological sensitive points primarily encompass the junctions of ecological corridors,as well as the intersections between ecological corridors and DEM ridge lines.The paper presents a strategy for constructing a comprehensive"surface-line-point"ecological protection spatial pattern that incorporates ecological red line areas(surface),ecological corridors(lines),and ecological nodes(points).The integration of these elements forms a robust ecological barrier system in Yan’an City,thereby enhancing the effectiveness of local ecosystem protection.Furthermore,the research findings of the paper can serve as a valuable methodological reference and foundation for establishing ecological protection spatial patterns and promoting environmental conservation practices throughout China.