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Vegetation community composition along disturbance gradients of four typical open‐pit mines in Yunnan Province of southwest China

Open‐pit mining causes severe land degradation in Yunnan Province, Southwest China. Vegetation restoration on the degraded land with open‐pit mining is challenging due to great physical and chemical condition changes of the post‐mined landscape. In this study, we compared the vegetation community composition and environmental factors along three disturbance gradients (mining area, restoration area, and control area) in four typical open‐pit mine types (phosphate, zinc, tin, and iron sites). Nonmetric multidimensional scaling analysis revealed that there are significant differences in the vegetation communities along three gradients for these mine sites. Quality species were selected by indicator species analysis for vegetation restoration as follows: Chloris virgata Sw. and Artemisia princeps Pamp at the phosphate site; Coriaria nepalensis Wall., Artemisia princeps Pamp, and Picris hieracioides L. at the zinc site; Artemisia princeps Pamp at the tin site; and Panicum brevifolium L. at the iron site. Canonical Correspondence Analysis ordination and Monte Carlo permutation tests were further used to determine the effects of environmental factors on vegetation diversity. The results showed that Cd, As, Zn, Pb, TC, and altitude all had significant effects on vegetation diversity (P < 0.05). Additionally, we found that the integrated effects of these variables on vegetation were greater in the mining area than in the other two gradients based on the model with the lowest Akaike Information Criterion. These results suggest that any plans for vegetation restoration in open‐pit mining areas should take disturbance intensity, mine types, and critical environmental variables into account.