露天煤矿排土场边坡植被组成特征及其群落稳定性评价

Slope vegetation characteristics and community stability at different restoration years of open⁃pit coal mine waste dump

研究植被恢复过程中植物群落组成、结构及稳定性的变化,可进一步了解到植物群落的演替过程及规律。采用空间代时间的方法对内蒙古锡林郭勒盟北电胜利露天煤矿4个排土场边坡人工恢复植被进行群落调查,在此基础上采用多样性指数与优化后的M.Godron稳定性指数对植物物种组成、物种多样性及其群落稳定性进行分析,探究不同恢复年限排土场边坡植被在恢复过程中群落特征及稳定性变化特征。结果表明:(1)排土场边坡植物物种组成共有16科44属56种,植物群落组成较简单,其中禾本科种类最多,生长型以草本植物为主。(2)随着恢复年限的增加,植物生活型由一、二年生转变为多年生,坡面优势种由人工种植植物转变为本土植物。(3)整体看,随着恢复年限增加,物种多样性呈下降趋势,群落稳定性整体呈上升趋势。(4)由于不同坡向土壤微环境差异,北坡恢复效果及稳定性好于南坡。本研究在一定程度上可为露天煤矿排土场边坡人工修复过程中植物物种及合理配置模式的选择提供科学依据。

Open⁃pit coal mine could destroy the original natural ecosystem,forming a considerable number of abandoned mining lands,causing a series of ecological problems as well.Revegetation is the core of ecological reconstruction,which has impacts on community characteristics and biological diversity of the vegetation,and does well to the soil physical and chemical properties at the same time.At present,studies on revegetation in mining areas,mainly focusing on the improvement of revegetation technology,the effect of vegetation and soil restoration,and vegetation allocation model,etc.There are less researches on the changes of plant community structure and stability in time series.As an important characteristic of ecosystem structure and function,community stability has an impact on the laws and characteristics of the stability of vegetation.M.Godron index is a classical method for community stability evaluation,but it can only reflect the stability of the plant community without considering the changes of community structure.Therefore,the comprehensive analysis of the stability and composition characteristics of the plant community can further understand the ecological characteristics and restoration process of the plant community in the mining area,which is significant to the ecological restoration of the mining area.In this study,the communities of artificial revegetation of 4 waste dump slopes in Beidian Shengli open⁃pit coal mine in Xilinguole League of the Inner Mongolia,were phytocoenologically investigated using the method of space⁃substitute⁃time.The community characteristics and stability in the process of revegetation of waste dump slope with different restoration years were explored.The species composition,species diversity,and community stability of vegetation were analyzed using diversity index and the optimized M.Godron index.The results showed that:(1)a total of 56 naturally occurring plant species,belonging to 44 genera and 16 families,were observed in the slope of waste dump which mainly composed by Gramineae plants and the major growth type was herbaceous plants.(2)With the increase of restoration years,the life form of plants changed from biennial plants to perennial plants,and the dominant species on slope changed from artificial plants to native plants.(3)On the whole,the species diversity decreased and the community stability increased with the increase of restoration years.(4)Due to the difference of soil micro⁃environment in different slope directions,the restoration effect and stability of north slope was better than the south.To some extent,these findings can provide a scientific basis for the selection of plant species and rational allocation mode in the process of artificial remediation of open⁃pit coal mine dump.