228 / 2023-09-28 10:09:08

Diagnosis of vegetation damage and ecological restoration assessment of open-pit mining in desertified grassland area

desertified grassland; Shendong mining area; open-pit mining; waste dump; vegetation index; ecological restoration

Studying the vegetation damage and reclamation status of open-pit mines and waste dump can provide ecological basis for diagnosing vegetation damage in mining areas. Based on Sentinel-1A SAR data, D-InSAR technology is applied to obtain the location, mining range and depth of open-pit coal mine. Using Sentinel-2A/2B MSI multi temporal remote sensing data, two vegetation indices (NDVI, EVI) and four red edge vegetation indices (RENDVI, MSR_RE, CIre, TCARI) were calculated as ecological restoration evaluation indicators. The trend change of the red edge normalized vegetation index (RENDVI) in the buffer zone was analyzed by using the single linear regression analysis method, and the spatio-temporal change rule of the vegetation in the waste dump and the buffer zone was obtained. Research shows that: (1) The area of the five open-pit coal mines and the reclaimed area of the waste dump increased year by year, of which the growth rate of the area of Wulanhada open-pit mine, Jingwei open-pit mine, Wujiata open-pit mine, Hongshengyuan open-pit mine and Wolf Woqiu open-pit mine was 34.73 hm²∙a^-1, 44.94 hm²∙a^-1, 21.81 hm²∙a^-1, 6.21 hm²∙a^-1, 110.95 hm²∙a^-1. (2) The vegetation indices of the mining area, waste dump and check area all showed an overall downward trend, and a negative slope of 91.6-95.8% was found through linear fitting. (3) Affected by climate change, five open-pit coal mines and check areas experienced a sudden increase in low vegetation cover and a sudden decrease in high vegetation cover in 2021. (4) Comparing the 5 km buffer zone and check zone of five open-pit coal mines, the RENDVI change trend shows a degradation trend per pixel, with the degradation area of the mining area buffer zone being over 50%, and the degradation area of the check zone being over 80%. (5) Through research on the Zhungeer open-pit mine, it was found that during the study period, the vegetation changes in the mine were consistent with those in the study area and the comparison area: the fitting slope of the vegetation index was negative, with a degradation area exceeding 65.0%, with a mild degradation area of 62.7%. Open-pit mining will exacerbate the ecological degradation of desertification grassland vegetation, and the restoration effect of waste dump is easily affected by climate change in the short term.