| The Yellow River Basin is a significant birthplace of agricultural civilization in China.However,it has suffered the threat of the ecological security due to the destructive development of human beings for the Yellow River Basin with the outages andpollutions of waterin recent years.Yuzhong County,located in the middle of Gansu Province,belonging to one of the three counties under the jurisdiction of Lanzhou City,is an important fulcrum ofthe Silk Road Economic Belt and the eastern development axis of Lanxi urban agglomeration,which is regareded as a key geographical location.Problems,such as the limited water resources,fragile ecological environment,and low carrying capacity of the Yellow River Basin in the Yuzhong region as well as related problems threatening the ecological security of the basin have become the biggest obstacle for the urban development of Yuzhong county.Therefore,it is of great significance to carry out the research on ecological security assessment of the Yellow River Basin in Yuzhong region to promote the establishment of the response mechanism of ecological protection,ecological protection,and high-quality development of this basin.In this paper,regarding the fragile ecological environment of the Yellow River Basin in the Yuzhong region,the section of the Basin under human disturbance was selected to establish a suitable index system for the ecological security evaluation of this basin using the improved Driving-Force-Pressure-State-Impact-Response(DPSIR)model with the characteristics of natural,social and economic activities in the basin.The methods of remote sensing interpretation and monitoring are also adopted tomaster the basic information of the Yellow River Basin in Yuzhong region,as well as the impact factors and trends of ecological security.For the four aspects of ecological environment pressure,ecosystem health,ecological service function,and ecological risk of the Yellow River Basin in Yuzhong region,the methodcombining qualitative analysis with quantitative research is applied to calculate the index weights,which will provide a scientific support for the ecological security and river basin management of this region.Theconclusions are as follows:(1)The comprehensive ecological security index(ESI)of Yellow River Basin in the Yuzhong regionwas indentified as the "general security" level,indicating that the social and economic pressure of the region is relatively high,the water ecosystem is subject to moderate human disturbance,the water quality is average,the habitat of species is moderately disturbed,and the service function of river ecosystem has been impaired to a certain extent,which basically meets human needs.The assessment of pressure,state and function of the Yellow River Basin in the Yuzhong sectionis at the level of "third level",and the risk is at the level of "second level".(2)The research of ecological security assessment involves ecological environment pressure,ecosystem health,ecological service function and ecological risk.The study on the pressure of ecological environment in the river basin shows that the population pressure,the pressure of land use,the pressure of urban pollution discharge and the external pressure of the river basin have great influence on it,and the biggest source is the pressure of urban pollution discharge,but the pressure of Water Resources Utilization is light.In the study of ecosystem health state,the comprehensive condition of water quality and physical habitat is good.The comprehensive condition of aquatic organisms is poor,which is mainly reflected in the proportion of wetland area,the integrity of macrobenthos and the integrity of fish.In terms of ecological service function research,drinking water service function and conservation area function are better.The ecological function of water conservation,water environment purification and biological diversity is weak.Among them,the water conservation index was low,the road pollution ratio was low and the habitat representation of rare species was poor.The ecological risks are mainly manifested in three aspects: low critical ratio of chemicals,relatively large number of exposed population in the basin and heavy metals.(3)In order to improve the ecological security of Yellow River Basin,the priory task is to establish and improve laws and regulations related to ecological security,which can effectively prevent and control the deterioration of ecosystem;then combining with the characteristics of basin ecosystem,to achieve coordinated regional development,and effectively promote the ecological security and high-quality development of the Yellow River Basin;In the meanwhile,it is necessary to strictly control the source of pollution,avoid the increasing pressure of urban pollution discharge,reduce human development interference,so as to effectively promote the ecological security of Yellow River Basin. |
