| Driven by the dual factors of global climate change and socio-economic activities,a series of problems such as ecosystem degradation,loss of biodiversity and land desertification are occurring frequently,and the conflict between human and environment is becoming more and more prominent.The ecological environment is an important foundation and guarantee for the maintenance and development of human society,and the quality of the ecological environment determines the ability and level of sustainable development of the region.A comprehensive,scientific and objective evaluation of regional ecological and environmental quality is an important prerequisite for achieving synergy between economy and environment,and is also an inevitable requirement for accelerating the construction of national ecological civilization.The Qaidam Basin is located in the northeastern part of the world’s "third pole" Qinghai-Tibet Plateau,which is characterized by drought and low rainfall,high winds and sand,desertification,salinization and land sanding,and other serious ecological problems,as well as a high degree of ecological and environmental vulnerability.Its unique natural geographical location and environment make it one of the most sensitive areas to global climate change and human activities.Scientific evaluation of the current ecological environment of the basin and reasonable prediction of change trends will help to provide ecological management and restoration plans according to local conditions and provide scientific basis for rational development and optimal allocation of resources in the basin.This paper takes the Qaidam Basin as the study area,integrates DEM data,meteorological data,soil data,remote sensing data,MODIS data,land use/cover data and socio-economic data,selects 17 evaluation indicators covering topography,meteorology,environment,vegetation,diversity,hydrology and society,etc.,adopts the SRP model,and constructs the ecological vulnerability evaluation The index system is supported by GIS technology,and the ecological vulnerability of the Qaidam Basin in four periods of 2000,2010,2015 and 2020 is comprehensively evaluated by using hierarchical analysis and comprehensive index method to further reveal its spatial differentiation characteristics,change patterns and driving factors,and try to predict the spatial pattern of ecological vulnerability in the basin in 2030 by using CA-Markov model.The following main research conclusions were obtained:(1)The average values of ecological vulnerability index in the Qaidam Basin in2000,2010,2015 and 2020 were 0.5396,0.5388,0.5069 and 0.4926,respectively,indicating that the overall ecological vulnerability degree of the Qaidam Basin showed a trend of continuous improvement in the past 20 years.In terms of the area of each vulnerability level,the area of the slightly and mildly vulnerable areas in the Qaidam Basin increased from 2000 to 2020,with an increase of 49,270 km2 in 2020 compared with 2000;the area of the moderately vulnerable areas remained relatively stable from 2000 to 2020 and slightly decreased,with a decrease of 6611km2;the area of severe and extremely vulnerable areas increased slightly from 2000 to 2010,with an increase of 4612km2,but in and rapidly decreased by 47,271km2 during2010-2020.(2)The global Moran index in the Qaidam Basin is 0.836,0.891,0.898 and0.914 in 2000,2010,2015 and 2020,respectively,indicating that the ecological vulnerability of the shows a high positive spatial correlation and a gradually increasing trend of aggregation.The ecological vulnerability index of the basin shows a gradually increasing distribution characteristic from the east to the west.The relatively humid climate of the Kunlun Mountains in the southeastern part of the basin and the Qilian Mountains in the northeastern part provide good conditions for vegetation growth,making the area less ecological fragility;the alluvial fan front area in the central part of the basin forms a unique desert oasis due to rich groundwater recharge,and the ecological quality is significantly better than other areas in the basin;the western part of the basin has scarce precipitation,strong evaporation,severe soil salinization and strong land sanding,and the highest ecological fragility.(3)The overall ecological improvement area of the Qaidam Basin during the20-year period from 2000 to 2020 is 126,465 km2,accounting for about 46.67%,and the improvement area is mainly distributed in the central and eastern parts of the basin;the unchanged area is 104,648 km2,accounting for about 38.62%,mainly distributed in the central and western parts of the basin;the deteriorated area is 39870 km2 which accounts for about 14.71% and is mainly distributed in the western part of the basin.Thus,it can be seen that the ecological quality of the Qaidam Basin has generally shown a trend of improvement in the last 20 years,and the ecological improvement in the central and eastern parts of the basin is better than that in the western part,the overall trend of the center of gravity of each ecologically fragile class in the basin is shifting towards the northwest.However,between 2010 and 2015,the ecological quality of the eastern part of the Qaidam Basin had also deteriorated in a larger area.Therefore,the monitoring and protection of the ecological environment of the basin still need to be given high priority.(4)The results of the geodetector model indicated land sanding,salinization,fractional vegetation cover,net primary productivity,and landscape disturbance as key drivers of the evolution of spatial and temporal patterns of ecological vulnerability in the Qaidam Basin.Interaction factor detection indicates the strongest interaction between land sanding and salinity,in addition to strong interactions with annual mean temperature,drought index,and elevation.Climate change is the main factor causing changes in ecological vulnerability,while human activities have a local impact on ecological vulnerability that cannot be ignored.Therefore,the treatment of a single environmental problem in the Qaidam Basin should not be the ultimate goal,but should simultaneously consider the compound effects of single and multiple factors to promote regional ecological construction.(5)The CA-Markov model achieved high simulation accuracy,and the prediction results of the spatial pattern of ecological vulnerability in 2030 showed that the area of the slightly vulnerable,mildly vulnerable,moderately vulnerable,severely vulnerable,and extremely vulnerable areas in the Qaidam Basin accounted for16.53%,27.82%,28.17%,21.19%,and 6.29%,respectively,by 2030.Compared with2020,the area of slightly and mildly vulnerable areas will increase substantially,the area of moderately and extremely vulnerable areas will decrease slightly,and the area of severely vulnerable areas will decrease substantially.It indicates that the overall ecological quality level of the Qaidam Basin will be further improved under the existing natural conditions and management level.Finally,this paper briefly put forward some countermeasures and suggestions for ecological management of the Qaidam Basin,which can provide realistic reference for the development of other resource-based regions in China. |
PDF Full Text Request