Vegetation coverage change and stability in large open-pit coal mine dumps in China during 1990–2015

Abstract

Ecosystem reconstruction via vegetation restoration is key to comprehensive renewal of the fragile ecological environment of an open-pit mine dump. To investigate vegetation coverage change and stability after mine dump land reclamation, three dumps in the Antaibao open-pit coal mine, northern Shanxi province, China, were used. This region has a typical temperate arid to semi-arid continental monsoon climate. Vegetation coverage was calculated from 11 Landsat remote images taken 1990–2015. Methods included calculation of the Normalized Difference Vegetation Index (NDVI), decomposition of mixed pixels, calculation of variation trends, and a transition matrix. The results show that vegetation coverage in the dumps increased dramatically from 1990 to 2015 (with NDVI rising from −0.02 to 0.02 in 1990 to 0.24 to 0.31 in 2015). The change in NDVI was classified mainly as significantly improved, to mostly moderately high coverage, by 2015. Water is a restrictive factor that greatly influenced the growth and development of vegetation. There was greater vegetation coverage and rate of improvement in coverage at higher elevations, and less coverage on steep slopes. Stability analysis of vegetation coverage succession and its recovery after a fire indicate that post-reclamation vegetation coverage in the dumps is relatively stable.