Responses of Vegetation and Soil to Artificial Restoration Measures in Abandoned Gold Mining Areas in Altai Mountain, Northwest China

Gold mining plays an essential role on the social and economic development. However, mining activities leads to destructive changes in ground structure and biodiversity, triggering considerable environmental problems. This study proposed a field observation to evaluate the short-term efforts of the artificial restoration measures taken by the Two-River Source Nature Reserve Administration from 2010 to 2015 in an abandoned gold mining area in Altai Mountain, Northwest China. The effects of different ecological restoration measures on soil and vegetation recovery were examined by calculating the richness index, dominance index, diversity index, evenness index, aboveground biomass, vegetation coverage, species number and soil-rock ratio index of the recovered area. Further, a principal component analysis (PCA) was used to compare the efficiency of each artificial measure. The results showed that gold mining activities cause serious environmental degradation in natural landscapes. The soil-rock ratio of the abandoned mining area was reduced by 98% compared with the original grassland. The surface vegetation was destructively destroyed, and the surface soil was stripped. Restoration measures considerably improved ecological conditions, which were reflected by surface biomass, diversity index and the soil-rock ratio, as well as accelerated ecological rebuilding processes in abandoned mining areas. The ecological efficiency of the single restoration measures assessed, such as soil measures, water replenishment measures and biological measures, was not significant. The average values of various indexes of these measures showed lower values of 0.12-0.45. The combination of various measures can not only improve the soil environment but can also lead to changes in plant community diversity and significant ecological efficiency. This was reflected by the values of various indexes, which reached higher values of 0.4-1.21. As far as the same kind of restoration measure is considered, the longer the restoration period, the better the recovery effect.