Dynamic changes in soil and vegetation during varying ecological-recovery conditions of abandoned mines in Beijing

Vegetation restoration in abandoned mines is very difficult and time consuming because of the harshness of the ecosystem, i.e., the extremely high and steep slopes. To accelerate the process of vegetation recovery in abandoned mines, understanding the rules of vegetation succession and the variation in soil characteristics during this process is very important. In the Zhoukoudian vegetation restoration experiment demonstration area (a 12 ha area located in Fangshan District, Beijing, China), engineering measures, such as biological greening bags, eco-stick slope protection, container seedling planting and vegetative-carpet greening technologies, were applied to accelerate the process of vegetation recovery. In this study, 149 human-restored and spontaneously recovering slopes under three substrates were sampled to investigate the dynamic changes in soil and vegetation in different stages of succession by means of space-for-time substitution. WinTWINS was used to classify the samples, which experienced different recovery periods, into 6 plant community types. According to the results, the species richness index, Simpson's predominance index, the Shannon-Wiener index and the soil fertility of the communities dominated by young trees (V, VI) were higher than those of the communities dominated by grasses (I, II) or shrubs (III, IV); thus, plant communities V and VI are considered optimal representations of severely damaged surface-mine ecosystems. Our results suggest that native species should be planted to accelerate the succession process by implementing the best engineering measures for different substrate types during the initial restoration.