| The high-level ecological disturbance effect in the process of coal mining will bring about environmental problems such as regional surface erosion and vegetation destruction.The natural conditions in the northwest region are harsh,and the ecological environment itself is extremely fragile.Coal mining has spatial diffusion and cumulative effects.When studying its ecological impact,it should not be limited to the inside of the mining area,but also consider the scope of its indirect impact.This paper focuses on the arid desert mining area,taking Ningdong mining area as an example,based on long-term serial remote sensing data,to study the spatial and temporal effects of environmental factors represented by vegetation within the mining area on mining disturbance,and to reveal the spatial and temporal evolution of vegetation disturbance by mining;and Using the principle of buffer zone and frequency ratio,the correlation of vegetation coverage changes in buffer zone at different distances is analyzed to define the ecological impact range of mining disturbance in mining area.The results indicate that:(1)The vegetation in the mining area showed an increasing trend in 2008-2017,and the overall vegetation condition is better;however,the standard deviation was gradually higher,which showed the spatial heterogeneity of vegetation in the area was enhanced.(2)The vegetation coverage of the mining area was obviously different,the vegetation situation in the southern area was obviously better when vegetation degradation in the central area was the most serious,which mained the overall vegetation in the northern area was improved,while polarization was obvious.(3)For the medium-scale typical Yangchangwan minefield,the overall vegetation status of the minefield and the surrounding buffer zone from 2015 to 2019 is better,but the vegetation status of the buffer zone relative to the interior of the minefield is relatively worse year by year,and mining activities have affected the surrounding area.Vegetation disturbance has time lag effect and spatial expansion effect.From the point of view of K value,as the distance increases,the vegetation status of the buffer zone is gradually improved relative to the internal vegetation status of the mine field.The vegetation status at the 300 m buffer zone is better than the interior of the mine field.The closer the mine area,the worse the vegetation status of the buffer zone.The correlation results of the K value of the buffers at different distances with time change are significantly correlated in the range of 100 m,and there is no obvious correlation in the buffer area of 150 m.The sensitive range of mining disturbance in the mining area of Yangchangwan Minefield is in the range of 100m-150 m.(4)The frequency ratio of bare land and inferior vegetation in the buffer zone within 8km of the mining area showed a significant increase,and the frequency ratio of superior vegetation increased.The increase in the ratio of bare land and inferior vegetation in each buffer zone beyond 8km gradually decreased to negative.There is no obvious change rule of vegetation coverage of other grades;the frequency ratio of the vegetation coverage of various grades of the mining area in the buffer zone in the reference zone is different from that of the mining zone in different buffer zones,and there is no obvious rule outside 10 km.The frequency ratio of different levels of vegetation coverage in each buffer zone outside the mining area has no correlation between 7-8km and beyond,and there is a significant correlation within 7km.The impact range of mining vegetation disturbance in the mining area is judged to be 7-8km.The frequency ratio of the grade vegetation coverage is significantly correlated within 2.5km and below,which is lower than the range of the mining area,indicating that mining activities in the Ningdong mining area have an impact on the growth of surrounding vegetation compared with the natural area,and the sensitive range can reach 7-8km. |
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