乌海矿区矸石山边坡植被重建初期物种多样性及群落稳定性

目的]针对西北干旱区煤矸石山边坡植被重建初期,探究不同建植年限群落特征的变化规律,为乌海市矿区生态重建的中、后期工作提供依据。方法]以乌海市矿区美方煤矸石山为研究对象,采用野外样方调查取样的方法,对比分析了矸石山植被重建初期的植物生长状况与群落稳定性。结果]①研究区植被重建过程中,物种数量明显增加。自然侵入植物种在重建2 a时仅有4种,建植3 a增加至6种,建植4 a已增加至7种。不同植被重建年限群落中白茎盐生草(Halogeton arachnoideus)均处于优势地位,表明群落正在进行正向演替过程。②随重建年限从2 a增加至4 a,植被平均盖度、地上生物量、群落丰富度指数均增加了1.5倍左右,表明群落结构逐步稳定。③煤矸石山,在植被重建2~4 a时,群落正处于演替初期,群落相似性系数逐年降低,群落结构趋于复杂化,但仍处于不稳定状态。结论]在矸石山后续的恢复中,在种植矿区典型复垦植物种,例如豆科、禾本科、菊科等植物时,应适当促进适应当地条件的本地物种自然定植,并且通过种植演替后期的本土植物种类在煤矸石山保留当地基因库。

Species Diversity and Community Stability at Early Stage of Vegetation Reclamation in Gangue Hill Slope of Wuhai Mining Area

Objective]The variation laws of community characteristics with different planting years were studied in accordance with the initial stage of vegetation restoration of the slope of a coal gangue heap in the arid area of Northwest China to provide the basis for ecological restoration in Wuhai mining area.Methods]The Meifang coal gangue heap in Wuhai mining area was taken as the research object,and the growth status of vegetation and community stability in the initial stage of vegetation restoration were compared and analyzed by using the method of sampling and surveying the field samples.Results]①The number of species increased significantly during the vegetation restoration.There were only four species of natural invasive plants in the second year of restoration;then,the number increased to six in the third year.In the fourth year,the number of species increased to seven,and the dominant species were Halogeton arachnoideus.The number of natural invasive plant species increased gradually,indicating that the community was undergoing a positive succession process.②The average vegetation coverage,superterrane biomass,and richness index increased by 1.5 times,with an increase in the restoration years from two to four,indicating that the community structure was gradually becoming stable.③The community of the coal gangue hill was in the initial stage of succession when the vegetation was reconstructed for two to four years.The similarity coefficient of community decreased year by year,and the community structure tended to be complicated,but it was still in an unstable state.Conclusion]In the following vegetation restoration of coal gangue hill,naturally permanent planting of local species that are adaptive for local conditions should be properly promoted when planting typical reclamation plant species,such as Leguminosae,Gramineae,and Compositae.In addition,the local gene bank should be preserved in the coal gangue hill by planting native plant species belonging to the climax stage of succession.