33 / 2023-03-29 15:01:08

Study on land ecological vulnerability and evolution of coal mining subsidence in Bulianta Mining area, Inner Mongolia

Bulianta mining area; coal mining subsidence; ecological vulnerability of land; stepwise regression method; surface deformation index; comprehensive index of soil fertility

The surface subsidence caused by coal mining disturbance and the change of soil physical and chemical properties have brought great pressure to ecological restoration, which is a difficult problem we have to face to restore the ecological environment. Based on Landsat remote sensing data, Sentinel-1A radar data and measured soil data, this paper established a comprehensive evaluation system of land ecological vulnerability in Bulianta mining area based on PSR model, aiming at the evolution of land ecological status before and after ecological treatment of coal mining subsidence, and analyzed the change of land ecological vulnerability. Through stepped-regression method, the index that has the greatest influence on the vulnerability of the land ecological in the mining area is found and analyzed from 12 indexes such as surface deformation index, per capita GDP, population density and soil fertility comprehensive index. The results show that:①The comprehensive evaluation results of land ecological vulnerability were divided into five vulnerability levels: slight (Grade V), mild (Grade IV), moderate (Grade III), high (Grade II) and severe (Grade I). The area proportion of Grade I area was 8.18%, 5.81% and 2.82% in 2006, 2012 and 2019, respectively. The area proportion of Grade V region was 24.94%, 29.00% and 35.24% in 2006, 2012 and 2019, respectively. The area of high ecological vulnerability level decreased gradually, while the area of low ecological vulnerability level increased gradually.②Surface deformation index and soil fertility index are the two indexes that have the greatest influence on the ecological fragility of mine land. The surface deformation index is positively correlated with the ecological fragility of mining area, while the soil fertility index is negatively correlated with the ecological vulnerability of mining area.③From 2006 to 2022, the land surface subsidence rate slowed down significantly with the passage of the collapse years. From 2006 to 2019, soil fertility factor showed an overall upward trend, and soil fertility in the study area became significantly better. The results of the study realize the rapid identification of ecological vulnerability changes in coal mining subsidence land, reveal the evolutionary drivers and trends of ecologically vulnerable areas, and lay the foundation for the subsequent ecological restoration and management of coal mining subsidence land.