不同植被恢复模式下矿山废弃地的恢复效果研究

Effects of Different Vegetation Patterns on Ecological Restoration in Mining Wasteland

为探讨矿山废弃地不同植被恢复模式对生态恢复效果的影响,以城门山铜矿排土场为研究对象,对7种不同植被恢复模式的植物群落结构、土壤养分和重金属含量进行调查分析,并与恢复前的排土场和未破坏的自然样地进行了比较。结果表明:(1)人工植被恢复群落的丰富度指数、多样性指数和均匀度指数呈现出相同的变化趋势,刺槐—苘麻—狗牙根的物种丰富度和多样性较高,而苘麻—狗牙根和刺槐—田菁明显低于其他模式。(2)植被恢复能有效改善土壤养分状况,降低重金属含量。与恢复之前相比,土壤速效K、速效N含量分别提高了2.5~7.7倍和3.4~7.9倍,但仍未达到自然水平;刺槐和苘麻对降低重金属Cu含量作用明显,刺槐和田菁能有效修复土壤Pb污染。(3)基于物种多样性、土壤养分和重金属含量的综合评价得出,刺槐—田菁—苘麻—狗牙根、刺槐—苘麻—田菁和刺槐—狗牙根—苘麻3种模式的生态恢复效果较好,可以为同类矿山废弃地植被恢复提供参考。

For the purpose of studying the effects of different vegetation restoration patterns on ecological restoration in mining wasteland,dumps of Chengmenshan copper mine was chosen as the study site so as to investigate and analyze plant community structure,soil nutrient and heavy metal contents under 7 different vegetation patterns,compared with the dumps before vegetation restoration and the undisturbed sites.The results showed that:(1)the richness index,diversity index and uniformity index of different vegetation modes showed the same trend;the community abundance and diversity of Robinia pseudoacacia-Abutilon theophrasti-Cynodon dactylon were higher,while these parameters were lower under Abutilon theophrasti-Cynodon dactylon and Robinia pseudoacacia-Sesbania cannabina than those under the other modes;(2)vegetation restoration could significantly improve soil nutrient status and decrease heavy metal contents;the soil available K and N increased by 2.5~7.7 times and 3.4~7.9 times,respectively,compared with the those before the restoration,but still did not reach up to the natural levels;the content of Cu remarkably decreased under Robinia pseudoacacia and Abutilon theophrasti,Robinia pseudoacacia and Sesbania cannabina could effectively remediate soil Pb pollution as well;(3)the comprehensive evaluation indicated that Robinia pseudoacacia-Sesbania cannabina-Abutilon theophrasti-Cynodon dactylon,Robinia pseudoacacia-Abutilon theophrasti-Sesbania cannabina and Robinia pseudoacacia-Cynodon dactylon-Abutilon theophrasti had better comprehensive improvement effects on ecological restoration,which can provide reference for similar mine wasteland.