Study On Land Use Change And Its Impact On Eco-environmental Quality Of Lin Xia Zhou

With the development of economy,the increase of population and the rapid expansion of cities and towns,the land use pattern has changed,which has an impact on the quality of ecological environment.Linxia Prefecture of Gansu Province is located in the fragile ecological area in the west,so it is very important to study the impact of land use change on the quality of ecological environment,which has practical significance for regulating land use and improving the quality of ecological environment.Therefore,this paper uses the object-oriented method to classify the lan d use of the image of Linxia Prefecture from 1993 to 2018,analyzes the land use quantity and spatial change characteristics of Linxia Prefecture,and uses the new remote sensing ecological index(RSEI)to comprehensively evaluate the ecological environment quality during the year,establishes the coupling model of land use change and ecological environment quality,and analyzes the land use category qualitatively and quantitatively The influence of type transformation on the quality of ecological environment.The research contents and results are as follows:(1)Based on the object-oriented method of land use classification,this paper analyzes the characteristics of land use change in Lin xia from 1993 to 2018 from the aspects of land quantity and structure change,dynamic change degree and transformation direction,and establishes the correlation coefficient model to explore the driving force of land use change from the social and economic aspects.The results show that:① from 1993 to 2018,the change of land use type shows a state of "four increase and two decrease",specifically,construction land,grassland,forest land and water area increased by 296.31km2,291.32km2,462.44km2 and 38.52km2 respectively,cultivated land decreased by 132.25km2 and unused land decreased by 956.46km2.② In terms of land use change types,grassland,forest land and unused land transfer frequently,among which construction land mainly increases,cultivated land area changes little,and unused land changes the fastest.③ The main driving forces of land use change in this area are economic development,urbanization rate and population factors.Among the three influencing factors,economic factors have the largest impact on land use change,followed by population factors,and urbanization rate factors have the smallest impact.(2)Based on the remote sensing image to extract the ecological indicators,the new remote sensing ecological index(RSEI)was integrated with principal component analysis to evaluate the quality of ecological environment in the study area,and combined with the characteristics of land use change to analyze the causes of ecological environment change.The results show that from 1993 to 2018,land use change led to the trend of deterioration and improvement of ecological environment quality,but the overall ecological environment quality was on the rise.The eco-environmental quality indexes of 1993,2003,2008,2013 and 2018 are 0.4535,0.4862,0.4456,0.4670 and 0.6956 respectively.The quality level of ecological environment has changed from "poor"(0.2≤rsei≤0.4)to "good"(0.6≤rsei≤0.8).Affected by the policy of protecting ecological environment,afforestation and soil erosion control have been implemented,and the overall ecological environment has been improved.The improvement area is mainly concentrated in the cultivated land and hillside grassland around the reservoir,which shows that the unreasonable use of land in Linxia has a great impact on the ecological environment.(3)The coupling correlation degree model is used to explore the coupling correlation degree of land use and eco-environment quality,and the land use types that affect the eco-environment quality are fitted with the change trend of eco-environment quality.The results showed that:(1)fitting the change trend of land use types and ecological environment quality,we can see that grassland and forest land play a positive role in the quality of ecological environment,and the increase of unused land area will seriously worsen the quality of ecological environment.②It can be seen from the establishment of the coupling relationship between land use and ecological environment that from 1993 to 2018,the coupling degree of the two changed from extremely uncoupled to a good development type,but the quality of ecological environment still shows a lag type,and the ecological environment protection needs further attention and improvement.③Cultivated land,forest land,grassland,water area and other land use types belong to ecological land,which plays a positive role in the ecological environment.Therefore,the higher the proportion of ecological land is,the better the quality of ecological environment will be.The change trend of ecological land is basically consistent with that of remote sensing ecological index.④The impact of land use change on the ecological environment can be divided into two categories:one is positive effect,such as afforestation,increasing the area of grassland,and improving the vegetation coverage;the other is negative effect,which is manifested in the desertification of degraded land of forest and grass,the conversion of forest land with high coverage into grassland with low coverage,resulting in serious deterioration of the ecological environment.