Evolution And Prediction Of Land Ecological Quality In Yanzhou Coalfield Driven By Coal Mining

With the development of high-intensity coal resources in China in the past 20years,the ecological and environmental problems in mining areas have become increasingly serious.On the basis of analyzing and summarizing the ecological evolution theory of mining areas at home and abroad,the thesis takes Yanzhou Coalfield as an example to deeply study the evolution law and driving factors of water environment,land use/cover,landscape pattern in mining land ecosystems.The thesis achieved the following main results:(1)Based on the Landsat data,the land use change and landscape pattern evolution in the three stages of Yanzhou Coalfield from 1990 to 2000,2000 to 2010and 2010 to 2018 were analyzed.Under the influence of coal mining,the subsidence area continues to increase,and industrial and mining construction land expands significantly;the subsidence water body changes the fastest;The transformation of land use types is mainly the conversion of cultivated land to construction land,subsidence water bodies and forest land,and there is also a transformation of construction land to cultivated land.From1990 to 2018,the landscape patch types of Yanzhou Coalfield are undergoing a fragmentation process.Cultivated land has always been in an advantageous position,and the advantage of construction land is increasing;the landscape pattern of Yanzhou coalfields shows a trend of fragmentation,irregularity,balance,and low connectivity.(2)Based on the water body information of Yanzhou Coalfield from 1990 to2018,the spatiotemporal evolution of the water body was analyzed,and the coal mining driving force model for the water body evolution was constructed.The water area of Yanzhou coal field is generally on the rise,increasing from 214.38hm~2 in 1990to 2717.73hm~2 in 2018.The water patch continuity is enhanced,and the driving effect of coal mining on the water body evolution of yanzhou coalfield keeps increasing.The coal mining driving index in the three periods is 7.3%,8.0%and 9.0%respectively.(3)A driving force analysis method of land use evolution based on logistic regression model was constructed,and the driving factors of land use change in Yanzhou coalfield were analyzed.The mining activity intensifies the change of cultivated land and construction land,and forms the change trend of increasing subsidence water body and decreasing cultivated land.The expansion of roads,residential areas and towns produces agglomeration effect.The development of urbanization is the main reason for the expansion of construction land and the decrease of cultivated land.The influence of natural factors is mainly reflected in the river and elevation.(4)A model of land ecological quality evaluation based on the degree of ecosystem stability and disturbance is constructed,and changes in land ecological quality are evaluated and predicted.From 1990 to 2018,the comprehensive index of land ecological quality in Yanzhou Coalfield continued to decrease,and the land ecosystem changed from stable to unstable.It is predicted that the land ecological quality grade will be third-class by 2030.Coal mining is the main reason for the decline in ecological quality and the instability of the land ecosystem.It is mainly manifested in the continuous decrease of vegetatio n coverage index,the increase of land subsidence area,and the increasing fragmentation of mining landscape.The paper has 27 pictures,25tables,and 104 references.