Responses of vegetation to depth to the groundwater table in the grassland openpit coal mine area

The drainage of groundwater caused by grassland mining activities leads to the decrease of groundwater level, which caused a dramatic degradation of grassland vegetation in surounding area. Understanding how grassland mining activities impact on the intensity and range of groundwater depth, determining threshold of depth to the groundwater table for vegetation growth would be a crucial prerequisite to protect the ecological environment of grassland mining area. In this study, Yimin open-pit coal mine in Hulun Buir grassland was investigated as an example. By introducing remote sensing method, the quantitative response relationship between depth to the groundwater table and Normalized Difference Vegetation Index(NDVI) before and after mining was established. How the composition of vegetation community change to the groundwater level and how the depth to the groundwater table influence the vegetation in terms of types, species richness, vegetation coverage, aboveground biomass and summed dominance ratio in gras