Abstract: The damage of coal mining on ecological environment has long been concerned. It is of significance to study the destroying mechanisms of the damage and related remediation methods to restore the damaged ecological environment in coal mining regions. This paper studied the impacts of coal mining on the wild plant species richness and species composition. A total of 16 out of 338 coal mines in northwest Shanxi Province were randomly selected to investigate the wild plant species in coal mine goaf area and coal mine non-goaf area, with the difference in the plant species richness and the similarity of the plant species composition between the goaf and non-goaf areas analyzed by Gleason richness index and Srensen similarity index, respectively. Coal mining decreased the wild plant species richness, and the wild plant species number was obviously lower in goaf area than in non-goaf area. Coal mining also induced the changes of wild plant species composition, resulting in an obvious difference in wild plant species composition between the goaf and non-goaf areas.

Key words: constructed wetland, hydraulic performance, dye tracer test, hydraulic residence time, normalization.