| With the rapid economic development,the natural ecological space is continuously squeezed by human activities,the regional ecosystem service function is continuously reduced,and the ecological sensitivity is increasingly prominent,which has a strong negative impact on ecological security and sustainable economic development.Since the 18 th Party Congress,China has been pushing forward the construction of ecological civilization and opening up a new era of ecological civilization,and the ecological protection and high-quality development of the Yellow River Basin have been brought to a new height.Therefore,how to carry out ecological protection and restoration of national space for the Yellow River basin and along the river at provincial,municipal,county,and district scales,to guarantee regional ecological security,has gradually become a national ecological strategic goal and research hotspot.In this context,the scientific delineation of ecological space based on the current ecological status of the region,taking the district and county scale areas that carry most of the population and agricultural activities in China as the target,can identify the dominant ecosystem service functions and outstanding ecological problems in the region,to clarify the key areas and carry out targeted protection and restoration,which is essential to meet the needs of ecological civilization construction and ecological protection and restoration of the national land space in China at the present stage.It is of great significance to meet the needs of ecological civilization construction and national spatial ecological protection and restoration in China at the present stage and to guarantee the ecological security of the whole situation.The Mengjin District of Luoyang City is located at the junction of the middle and lower reaches of the Yellow River Basin,straddling both banks of the Yellow River,with the Yellow River Wetland National Nature Reserve,Xiaolangdi Provincial Forest Park and two reservoirs,Xiaolangdi and Xixiayuan.The importance of ecosystem service function and ecological sensitivity were assessed based on the indicators: water balance method was used to assess the importance of water conservation function in Mengjin District;modified soil erosion equation(RUSLE)was used to assess the importance of soil and water conservation function in Mengjin District.The importance of the biodiversity maintenance function in Mengjin was assessed using the vegetation net primary productivity method,and the sensitivity of soil erosion in Mengjin was assessed using the soil erosion equation.On this basis,the assessment results were spatially overlaid,aggregated and corrected for concentration evaluation to obtain the results of ecological space delineation in Mengjin District.On this basis,combined with the fieldwork results,three types of key areas in Mengjin District that are in urgent need of ecological function maintenance and problem restoration and two types of other key ecological protection areas were identified.The main research results and conclusions are:(1)According to the results of the assessment of the importance of water connotation function,the importance of soil and water conservation function and the importance of biodiversity maintenance function,it can be seen that the water connotation capacity of the whole Mengjin District is strong,among which the area of extremely important area and important area of water connotation function are135.86km~2 and 193.20km~2 respectively,accounting for 40.60% of Mengjin District;the area of secondary important area and general area are 327.75km~2 and 327.75km~2 respectively.The total area of the secondary important area and general area is327.75km~2 and 153.62km~2 respectively,accounting for 59.40% of Mengjin District.The overall capacity of soil and water conservation in the whole area of Mengjin District needs to be improved,among which the area of extremely important area and important area of soil and water conservation are 21.69km~2 and 155.10km~2 respectively,with the total area accounting for 21.84% of Mengjin District;the area of secondary important area and general area are 320.53km~2 and 312.36km~2 respectively,with the total area accounting for 78.17% of Mengjin District.The biodiversity maintenance function of the whole Mengjin District is strong,in which the areas of extremely important area and important area of biodiversity maintenance function are 123.05km~2 and 103.28km~2 respectively,with the total area accounting for27.92% of Mengjin District;the areas of secondary important area and general area are 223.45% and 360.66km~2 respectively,with the total area accounting for 72.07% of Mengjin District.(2)According to the results of soil erosion sensitivity assessment,the overall sensitivity of soil erosion in the whole area of Mengjin District is moderately high,of which: the areas of extremely sensitive and sensitive areas of soil erosion are16.64km~2 and 128.36km~2 respectively,with the total area accounting for 17.92% of Mengjin District;the areas of generally sensitive and insensitive areas are 336.12km~2 and 328.05 km ~2,with a total area of 82.08% of Mengjin District.(3)According to the results of the preliminary evaluation of the ecological space delineation and grading of Mengjin District obtained from the spatial overlay,it can be seen that there are a large number of ecological spaces in Mengjin District that need to be protected urgently,among which: the area of extremely important area for ecological protection in Mengjin District is 208.30km~2,accounting for 25.69% of the national land area of Mengjin District;the area of important area is 258.40km~2,accounting for 31.87% of the national land area of Mengjin District;the area of secondary important area and The area of secondary important area and general area are 192.91km~2 and 151.12km~2 respectively,accounting for 42.43% of the national land area of Mengjin District.(4)Analysis of the final results of the ecological space delineation of Mengjin District obtained after the aggregation process and concentration evaluation based on the preliminary results shows that the revised area of the extremely important area of Mengjin ecological protection increased to 216.13km~2,the area of the important area increased to 270.63km~2,the area of the second important area decreased to 137.38km~2,and the area of the general area increased to 186.73 km ~2.The changes of the proportion of the land area of Mengjin District are 0.96%,1.51%,-6.85% and 4.39%respectively.After intersecting with the current situation of land use,it can be seen that the revised and optimized delineation results have a high degree of convergence with the current situation,and the overlapping area between the ecological protection zone of Mengjin District and the existing construction land is 5.99km~2,which only accounts for less than 0.01% of the national land area of Mengjin District,and can be used as a scientific guide and basis for the ecological protection and restoration of the national land space of Mengjin District.(5)According to the final evaluation results,the extremely important ecological protection areas in Mengjin District were divided into the following three categories:the biodiversity maintenance area of wetlands along the Yellow River,the comprehensive control area of soil and water conservation and erosion in the south of the reservoir,and the water-conserving function maintenance areas in the northeast,southwest,north and along the Yellow River;based on the results of the field survey,two other important areas were identified in combination with the regional characteristics of Mengjin District: the ecological improvement area of agricultural land and the ecological protection coordination area of construction land.The other two important areas were identified based on the results of the field survey: the ecological improvement area of farmland and the ecological protection coordination area of construction land.On this basis,the ecosystem service functions or ecological problems that need to be protected in each of these areas are analyzed,and corresponding control measures are proposed,which can be used as reference suggestions for the ecological protection and restoration of the national space in Mengjin District. |
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