Effect of soil and topography on vegetation restoration in an opencast coal mine dump in a loess area

Restoration and reconstruction of vegetation play an important role in improving and restoring the fragile ecological environment in disturbed areas. In opencast coal mine dumps in loess areas,the ecological environment is extremely fragile. Therefore,it is crucial to understand the effects of topography and soil factors on the response of vegetation restoration in order to improve the damaged ecosystems in mining areas. Here,we determined the effects of soil and topography on the response of vegetation to restoration activities at 27 reclamation sample plots( each with two transects) with different site conditions in the Shanxi Pingshuo Antaibao Opencast Coal Mine in a loess area. We conducted one-way analysis of variance( ANOVA) tests and pairwise tests of significance with SPSS 20. 0. We performed multivariate techniques,including detrended correspondence analysis( DCA) and redundancy analysis( RDA) using the program CANOCO 4. 5.The ANOVA and pairwise tests indicated that environmental factors significantly effected changes in vegetation.Available K( AK) had the most significant impact on vegetation restoration( P 0. 01),followed by total N( TN) and bulk density( BD)( P 0. 05). However,topography variables did not significantly effect changes in vegetation( P 0. 05). Soil nutrients were the main factors affecting the distribution and growth of vegetation during the process of restoration in this opencast coal mine dump in a loess area.The RDA results indicated that vegetation and soil variables were significantly correlated,whereas the correlation between vegetation and topography variables was not significant. There was a strong correlation between vegetation and environmental factors with species-environment correlations of 0. 811 on the first axis and 0. 702 on the second axis. The cumulative percentage of variance in the species occurrence data on the first four axes of the RDA was 59. 9%. The cumulative percentage of variance for the species-environment relationship on the first axis was 75. 3% and on the second axis was 20. 1%. Thus,the first axis and second axis explained 95. 4% of the variation in the relationship between species and the environment. This indicated that the species and the environment axes were highly correlated with the set of variables. The Monte Carlo permutation test indicated that vegetation restoration was not associated with all the environmental factors( P 0. 05). AK played an important role in vegetation change. The soi