| With the development of cities,there are often varying degrees of ecological problems in the development and utilization of land resources,leading to the compression of ecological space and the destruction of the ecological environment.After the 18th National Congress,the country paid more attention to ecological protection and high-quality development in the Yellow River Basin.Therefore,doing a good job in ecological environment protection and restoration to ensure regional ecological security has become a current research hotspot.As the largest tributary of the Yellow River,the Wei River has a significant impact on the region.This article takes the Weihe River Basin as the research object,evaluates the importance and sensitivity of ecosystem service functions from a dual perspective,and completes the identification of ecological space.At the same time,the identification results are combined with the analysis results of water security patterns to complete the evaluation of ecological space importance and the study of zoning management and control strategies.The main research results are as follows:(1)Based on In VEST model and ArcGIS spatial analysis technology,the importance and ecological sensitivity of ecosystem service functions in Weihe River Basin were evaluated.In view of the ecological and environmental problems of the basin,the In VEST model was used to assess the water yield,soil conservation and habitat quality and classify the importance levels.Meanwhile,the classification results were superimposed according to the weights.The study area was dominated by the highly important ecosystem service area,covering an area of 49,409km~2,accounting for 36.6%of the basin area,mainly concentrated in the Qinling Mountains.Around Ziwu Ridge and Liupan Mountain;The areas of the generally important areas and the extremely important areas are 363,37km~2 and 265,57km~2,respectively.The distribution of the extremely important areas is relatively scattered and there is little concentration phenomenon.The main land types are grassland and shrub land,and the generally important areas are mainly attached to the surrounding areas of the highly important areas and the extremely important areas,among which the Guanzhong area is the most obvious.According to the characteristics of topography and ecological environment in Weihe River Basin,the sensitivity of soil erosion and desertification was selected for ecological sensitivity analysis.The ecological sensitivity of the study area is mainly low and medium sensitivity,which is greatly affected by soil and water loss,and the distribution of very low and very high sensitivity is the most concentrated,with an area of 8831.29km~2 and 4034.16km~2,respectively located in the western loess Plateau gully region and the northern loess hilly region of the Weihe River basin.The low sensitive area is the largest,with an area of 62,513.98 km~2,accounting for 46.34%,mainly located in the upper and middle reaches of the basin,and there are more agricultural farming areas in this area.The middle sensitive area is the second most,concentrated in the northern foot of Qinling Mountains,which has high vegetation coverage and little disturbance from human activities.(2)The ecological space of Weihe River Basin was identified based on the evaluation results from two angles.Based on the evaluation results,a two-dimensional correlation matrix model was constructed to identify the ecological space of Weihe River Basin,and it was divided into the following three regions:first-level region,second-level region and third-level region.The total area of ecological space is 94237.27km~2,accounting for 69.81%of the basin area.Overall,the ecological environment quality of Weihe River Basin is high.The first level of ecological space is the least,which is the key area to ensure ecological security.The secondary zone has the widest distribution range and is the buffer zone between the primary zone and the tertiary zone.The three levels of ecological space are mostly located on the edge of the city.(3)Based on SCS-CN model,the analysis of water security pattern in Weihe River Basin was completed.The security pattern of water source protection is identified by constructing buffer zones with different distances of river system and reservoir pit in the basin.SCS-CN model was used to simulate rainfall inundation range and identify stormwater safety pattern.According to the bottom line principle,the two are superimposed to obtain a comprehensive water security pattern.The area of low security is 1504.38km~2,mainly distributed in Guanzhong Plain,which is close to the river and lake system and has a high risk level,so it is necessary to improve the vegetation coverage rate and formulate flood control measures.The medium safe area is distributed around the low safe area,and there is a certain range from the river and lake system,and there is still flood risk,so the development behavior should be limited and the flood regulation and storage function area should be established.The high security areas are mainly distributed in Xianyang and Weinan,which play a certain role in the stability of water system.The existing vegetation management should be strengthened to ensure the safety of rainwater.(4)Research on the zoning and control strategies of ecological space in the Wei River Basin from the perspective of water security.On the basis of the results of ecological space identification and the results of water security pattern,the importance of ecological space was evaluated by disjunctive operation,and the areas of general,important and extremely important areas were 32455.45km~2,42369.39km~2 and 22242.17km~2,of which the most important areas were located in the Qinling Mountains in the south,Mount Liupan in the middle and the highly sensitive areas of land desertification in the north of the Weihe River basin.Based on the evaluation results of the importance of ecological space,the control zone is divided into ecological function maintenance zone,remediation zone,and restoration zone.Based on this,the ecological service functions or existing ecological problems that need to be protected in different control zones are analyzed,and corresponding management and control suggestions are proposed. |
