| In Peibei coal mine area,there are plentiful coal resources.Long-term highintensity mining has caused land subsidence and ecological environmental changes.These situations will continue with the mining of coal resources.Taking Peibei coal mine area as the research object,using the related theories of landscape ecology,environmental science and mining subsidence,the long term landscape pattern evolution and trend were systematically studied by RS and GIS technology.Based on multi temporal remote sensing image data,the landscape pattern and vegetation cover change characteristics were analyzed.The ecological risk was quantitatively analyzed from three dimensions: geological hazard,landscape vulnerability and ecological loss.This thesis also predicted and discussed the trend of mining subsidence,and the trend of land use and geological hazard risk in mining area.The main results are as follows:(1)Identifiability changes have taken place in Peibei coal mine area land use.Cultivated land,construction land and water are the main types of land types,and the obvious reduction of cultivated land area has mainly changed into construction land and water area.The area of subsidence water increased from 3.00km2 in 1990 to 30.30km2 in 2017,which greatly changed the spatial distribution characteristics of water areas.(2)The landscape pattern is constantly changing,and coal mining is the main driving force for pattern changes.The shape of landscape patches tends to be complex and the connectivity is good.As dispersibility first increases and then weakens,the diversity increases and the distribution of landscape types tended to be balanced.The pattern of cultivated land is relatively stable,and the dispersion of construction land is enhanced,and the dispersibility of unused land is reduced.The changing trend of coupling coefficient and coordination coefficient is consistent,the role of coerce in1990 and 2006,antagonistic in 1998,and the coal mining and landscape pattern change tended to develop during 2014-2017.(3)The vegetation coverage in the Peibei coal mine area decreased,and the average vegetation cover index decreased from 0.67 in 1990 to 0.52 in 2017.The pattern of vegetation cover was fluctuating,the shape of the vegetation pattern tended to be complex,the agglomeration reduced and the diversity increased,the spatial distribution tended to be balanced;the vegetation coverage changes are featured by slightly reduced and increased,and the area of reduction is obviously larger than increasing.(4)The ecological risk of the Peibei coal mine area increased first and then decreased.A three-dimensional ecological risk assessment framework was constructed and the risk of geological hazards was assessed using an information-weighted model.The comprehensive index of ecological risk increased from 1.59 in 1990 to 2.13 in 2006.The risk of geological disasters and landscape vulnerability increased,and the coverage of vegetation decreased.The eco-environment index fell to 1.95 in 2017,which was mainly due to the reduction of geological disaster risk and landscape vulnerability,and the restoration of vegetation coverage to some extent.(5)The forecast results show that the coal mining subsidence area in the Peibei coal mining area will expand by 2030,the water area will continue to increase,and the risk of geological disasters will tend to decrease.The probabilistic integration method was used to predict the mining subsidence trends in the study area in 2020,2025 and 2030.The subsidence area was 164.57 km2,176.33 km2 and 209.97 km2,respectively.The land type will mainly convert into arable land and construction land.The water area is 216.29km2,217.03km2 and 224.61km2 respectively.The area of high geological hazard risk will gradually decreases,while the area of low value areas will gradually increases. |
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