| Since the reform and opening up,China has always attached importance to ecological and environmental issues,but in recent years,with the rapid development of China’s social economy and the increasing demand for environmental resources by the people,our country has also paid more and more attention to the ecological construction of the economic zone.In the outline of the 12 th Five Year Plan,Ningxia Economic Zone along the Yellow River is listed as the main functional area of national key construction.The economic zone is located on the golden bank of the Yellow River and has an important strategic position of ecological construction node,ecological protection barrier and ecological connection channel in China.The sustainable development of the economic zone is closely related to the state of the natural environment.Ecological vulnerability is an important basis to measure the environmental degradation,social development and future development planning of a region.Therefore,the study on the ecological vulnerability of Ningxia Economic Zone along the Yellow River has certain theoretical and practical significance for the ecological construction and sustainable development of the economic zone.Based on the Vulnerability Scoping Diagram(VSD)framework,this paper selected evaluation indexes from three aspects of exposure,sensitivity and adaptive capacity,and constructed an evaluation model of ecological vulnerability in Ningxia Economic Zone along the Yellow River by means of remote sensing and GIS technology and combined with the Spatially Explicit Resilience-Vulnerability(SERV)model.A comprehensive quantitative assessment of the ecological vulnerability of the economic zone from 2000 to 2019 was carried out.By analyzing the change characteristics of its vulnerability in time and space,this paper explored its evolution mechanism and driving factors,predicted the ecological vulnerability of the economic zone in 2023,the following conclusions were drawn:(1)From 2000 to 2019,the exposure index and sensitivity index of Ningxia Economic Zone along the Yellow River showed a downward trend,and the adaptive capacity index showed a downward trend first and then stable trend.The decline of exposure index and sensitivity index had a great impact on the reduction of ecological vulnerability in the region.(2)On the whole,the ecological vulnerability level of Ningxia Economic Zone along the Yellow River was mainly mild and moderate vulnerability,accounting for more than50% and up to 62.86%(2019).The ecological vulnerability synthetical index(EVSI)values in 2000,2005,2010,2015 and 2019 were 2.88,2.86,2.74,2.71 and 2.56 respectively,showing a slow downward trend.The ecological environment was developing towards stable improvement.However,the average EVSI for many years was2.75,which was still at the moderate vulnerability level as a whole.From the county scale analysis,the average EVSI of Helan County,Xixia District,Jinfeng District,Xingqing District,Yongning County and Litong District were all below 2,and their overall ecological environment were in a mild vulnerable state;The average EVSI values of Huinong District,Dawukou District and Shapotou district were above 3,and their overall ecological environment were in a severe vulnerable state;The average EVSI of Pingluo County,Qingtongxia City,Lingwu City and Zhongning county were between 2 and 3,and their overall ecological environment were in a moderate vulnerable state.In addition,over the past 20 years,the ecological vulnerability of Pingluo County,Helan County,Xixia District,Xingqing District,Yongning County,Litong District,Lingwu City,Zhongning county and Shapotou district showed a downward trend.(3)From 2000 to 2019,the area change of ecological vulnerability level in Ningxia Economic Zone along the Yellow River was mainly transferred to adjacent levels,and the relationship between transfer in and transfer out was complex,but generally showed the law of transfer from high level to low level.The center of gravity of ecological vulnerability level also migrated to varying degrees.Among them,the overall migration trend of the center of gravity with potential vulnerability was to the northeast;The migration direction of the center of gravity with mild vulnerability was first northeast(2000-2010)and then southwest(2010-2019);The migration direction of the center of gravity with moderate vulnerability was first Southwest(2000-2015)and then northeast(2015-2019);The migration trajectory of the center of gravity with severe vulnerability showed a "W" shape,and the overall trend was westward migration;The center of gravity with extreme vulnerability had a large migration range,the migration trajectory was "U" shape,and the overall trend was westward migration.The center of gravity of ecological vulnerability in the economic zone mainly migrated to the southwest,and the maximum migration distance was 6.65 km from 2000 to 2005.Overall,it showed that the development of ecological vulnerability in all directions along the Yellow River Economic Zone in Ningxia was uneven.(4)The ecological vulnerability of Ningxia Economic Zone along the Yellow River was the result of the combined effects of natural conditions and human activities in the area.Among them,soil type,land use pattern,NDVI,NPP and the gross output value of agriculture,forestry,animal husbandry and fishery per unit area were the main driving factors for the change of ecological vulnerability in Ningxia Economic Zone along the Yellow River in recent 20 years.Therefore,we should strengthen the positive impact of human activities on the regional ecosystem,so as to improve the carrying capacity of the ecological environment and the adaptability and self-regulation ability of the ecosystem in the face of external interference.(5)Under the existing environmental factor driven mode,it is predicted that the EVSI value of Ningxia Economic Zone along the Yellow River will be 2.40 in 2023,and the overall ecological environment will still be in a state of moderate vulnerability.The distribution area of each ecological vulnerability level will be mild vulnerability level,moderate vulnerability level,potential vulnerability level,severe vulnerability level and extreme vulnerability level from large to small.Compared with 2019,the area of each ecological vulnerability levels will mostly shift to the direction of low level,and the ecological vulnerability will be weakened.Figure [26] Table [14] Reference [107]... |
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