| As an important grassland animal husbandry base and ecological barrier in China,the sustainable development of the western pastoral area's ecological environment is of great significance to the stability of the border areas and national unity.Aiming at the problems of ecological environment in pastoral areas in western China,this paper selected Etuoke county of Inner Mongolia Autonomous Region.Sunan Yugur Autonomous county of Gansu province and Wulan county of Qinghai province as typical research areas in western China,and adopt quantitative evaluation of soil quality in the study area by weighted synthesis method and correlation coefficient method to analysis and research on the influencing factors of natural and human activities in eco-environment of these areas.Determin.ing index weight based on expert consultation and analytic hierarchy process,using PSR conceptual framework model to construct eco-enviroronmental evaluation index system and Comprehensive Weighted model for calculating eco-environmental health value of typical pastoral areas in western China to establishment of an Optimized model for sustainable utilization of ecological environment in pastoral areas of western China.The main results are as follows.(1)Aiming at the problem of ecological environm,ent health in the study area,the natural impact factors of ecological environment in the study area were analyzed from the four aspects of topography,landform,meteorology,soil and vegetation by 23 factors.The results show that:The mean value of topographic potential index in three typical research areas is greater than 0.55.The northwest of Etuoke county,the south of Sunan county and the rest of Wulan county except the basin have large slopes,high elevations and large topographic position index.Soil and water loss should be paid attention to.From 2001 to 2018,the annual average precipitation an d temperature in the three major research areas increased.Overall,the frequency of negati've anomaly was higher than that of(positive anomaly.Soil compactness,serious desctificstion,low water content and low nutrient content in the three major research areas are accompanied by salinization of varying degrees.Average vegetation coverage is 0.47 in Etuoke county from 2010 to 2015,Sunan county was 0.35 and Wulan cournty was 0.37.In terms of time distribution,the average vegetation coverage in Etuoke county declined during the six years from 2010 to 2015,while the average vegetation coverage in Sunan county and Wulan county was relatively stable.From the point of view of spatial distribution,the vegetation coverage in the west of the three research areas is significantly lower than that in the East due to climate factors.(2)From the three aspects of water resources ecological carrying capacity,land use and social economy,19 factors were analyzed to analyze the impact factors of human activities ecological environment in the study area.The results show that:Agricultural water footprint is the main component of ecological footprint in typical pastoral areas in western China;In recent years,the ecological footprint of 10,000 yuan GDP of typical pastoral areas in western China has been decreasing year by year.The ecological pressure index of water resources in Etuoke county and Wulan county is greater than 1,which fails to realize sustainable utilization of water resources.Grassland is the most important land use type in the typical pastoral areas of western China.The annual change rates of land use degree in Etuoke county,Sunan county and Wulan County were 0.34,0.17 and 0.31%,respectively.The land use degree of the three maj or research areas is in the trend of development,but the land use degree is not high.The reclamation index is generally rising steadily from 2005 to 2015,and the per capita cultivated land area is increasing year by year.From 2005 to 2015,the main economic impact factors of typical pastoral areas in western China showed an increasing trend year by year,and the self-increasing rate was positive,while the other social factors showed a fluctuating trend.(3)Based on 10 indicators,combined with correlation coefficient method and weighted summation model,the comprehensive values of soil quality in each study area were calculated.The present situation of soil quality in typical pastoral areas in western China is as follows:Wulan county>Sunan county>Etuoke county,Etuoke county and Sunan county have little difference in surface(0-20cm)and subsurface(20-40cm)soil quality index,and the average value of surface soil quality index in Wulan county is obviously larger than that in subsurface.The soil quality index in April 2018 was higher than that in November 2017.Spatially,the soil quality in the eastern part of Etuoke county is better than that in the western part;the content of organic matter in the central part of Sunan county is higher,the soil salinity is lower,the soil salinization degree is lower,the soil condition in the northern and eastern part of Wulan county is better,and the soil quality in the central and southern part of Sunan county is worse.Soil quality index is mainly affected by topography,climate and vegetation.(4)The optimization model of sustainable utilization of ecological environment in Western Pastoral Areas constructed by PSR conceptual model can accurately evaluate the ecological environment health status of typical pastoral areas in Western China.The results show that:From 2010 to 2015,the eco-environmental health value of Etuoke county showed a trend of"rising and falling",and tended to be stable in 2014?2015,which was in the middle level of eco-environmental health.The health value of ecological environment in Sunan county shows a decreasing trend.The main reasons are the increase of population,the increase of livestock farming and the increase of tourist population,which leads to the increase of ecological environment pressure and the decrease of health value.The growth rate of ecological environment health value in Wulan county is the biggest from 2014 to 2015.It is a high level of ecological health in 2015.Compared with 2010,the main factors controlling the significant increase of ecological environment health value are the income of farmers and herdsmen and vegetation coverage. |
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