Study On The Spatial And Temporal Evolution Of Ecological Environment Vulnerability In Five Provinces In Northwest China

With the continuous increase of the population,the extent of human damage to soil and water resources is increasing,which causing serious eco-environment problems in five northwestern provinces.During this period,a series of ecological restoration and protection work has been carried out in China,which has been strongly curbed the degeneration of the eco-environment and prompted the restoration of the local environment.However,eco-environment problems are still grim.The eco-environmental vulnerability evaluation can analyze spatial distribution and dynamic change of vulnerability and provide theoretical support for ecological protection and management under the background of national strategy of building ecological civilization in the five northwestern provinces.15 indices were selected from hydrological,land,biological,social and economic environment to construct the eco-environmental vulnerability index system of the research area.The entropy weight method was used to determine the contribution of index for factor to evaluate the spatial distribution pattern of eco-environmental vulnerability in the period.On this basis,the spatial and temporal variation trend and spatial distribution characteristics of eco-environmental vulnerability were compared and analyzed in the period from 2000 to 2017.The spatial analysis method was used to determine the distribution of cold and hot spots.After that,the gravity center transfer model was used to analyze the center of gravity shift of spatial distance between 2000 and 2017.Then the suggestions and measures for eco-environment restoration and construction were determined based on the vulnerability and actual situation of the research area.The main conclusions are as follows:(1)Ecological environment vulnerability is at a high level.The increased area of eco-environmental vulnerability are 31.8%,26.74% and 20.3% respectively,and decreased area of the eco-environmental vulnerability are 26.1%,30.04% and 8.7% respectively,stable area of the eco-environmental vulnerability are 42.1%,43.22% and 71% respectively in the three study period of 2000~2017?2010~2017?2000~2010.The results showed that eco-environment was recovering slowly from 2000 to 2017.(2)From the dynamic change of eco-environmental vulnerability,the regions where ecological environment vulnerability is reduced are mainly distributed in Shaanxi province,the southeast of Gansu province,the south of Ningxia,and a small part of Xinjiang and Qinghai.The regions eco-environment remains basically stable where in the desert,gobi and other unmanned areas,as well as in the forest regions where the ecosystem structure is relatively complete and stable.While the regions where human activities are intense and the ecological transition zone and other places where human activities can be involved,the eco-environment is in a seriously fragile state.(3)From the spatial correlation of eco-environmental vulnerability,the eco-environmental vulnerability showed a spatial distribution pattern of highly hot spots and cold spots from 2000 to 2017,from 2010 to 2017 and from 2000 to 2010.From the migration of the center of gravity,eco-environmental vulnerability first shifted to the northwest and then to the southwest from 2000 to 2017.(4)From the changes of eco-environmental vulnerability in the five provinces,the change of eco-environmental vulnerability was the largest and showed a good trend in Shaanxi province from 2000 to 2017.The eco-environmental vulnerability of Gansu and Ningxia decreased obviously from 2000 to 2017.The eco-environmental vulnerability of Qinghai and Xinjiang is declined from 2000 to 2017.