采煤沉陷区林下植物多样性与土壤因子的关系

Relationship Between Understory Plant Diversity and Soil Factors in Coal Mining Subsidence Area

为了研究荒漠草原采煤沉陷区生态恢复效果和影响草本层物种多样性的土壤因子,采用时空替代法,选择人工恢复5,7年的区域作为研究样地,并将未种植样地(C)作为对照组。通过野外植物群落调查和土壤采样,研究了不同恢复年限的物种多样性及其与土壤因子间的关系。结果表明:(1)相较于对照区,人工恢复增加了菊科(Compositae)、苋科(Amaranthaceae)的数量,减少了禾本科(Gramineae)的数量;人工恢复5年后物种数增加,7年后物种数减少,且多年生草本植物的比例逐渐减少;人工恢复提升了灌木层物种丰富度。(2)人工恢复7年后显著增加了草本层的Shannon-Wiener多样性指数(P<0.05),优势种由以华虫实(Corispermum stauntonii)为主的单优群落逐渐转变为以刺藜(Dysphania aristata)、大赖草(Leymus racemosus)、草木樨状黄耆(Astragalus melilotoides)、狗尾草(Setaria viridis)等为主的多优群落。(3)在采煤沉陷区进行植被的人工恢复可以提高土壤含水量和全氮含量,且对土壤全氮的影响更显著(P<0.05)。相关性分析表明,土壤含水量是对沉陷区草本层Shannon-Wiener、Simpson和Pielou指数影响最大的环境因子,土壤全氮对Shannon-Wiener指数也有影响。研究结果表明,在采煤沉陷区进行植被的人工恢复对提高土壤含水量、土壤全氮,以及改善研究区植被群落结构、提高植物物种多样性具有积极意义。

To study the ecological recovery effect and soil physical and chemical factors affecting the species diversity of herb layer after land subsidence in mining area,we adopted the space-for-time substitution,selected the area of artificial recovery for 5a and 7a as the study sample sites and a sample site without artificial planting(C)as the control group.The plant species diversity index,and its correlation with soil physical and chemical factors within different recovery years were studied based on field plant community survey and soil sampling.The results showed that:(1)Compared with the control area,the number of Compositae and Amaranthaceae increased,and the number of Gramineae decreased.The number of species increased after 5 years,decreased after 7 years of artificial recovery,and the proportion of perennial herbs decreased gradually.Artificial recorvery improved the species richness of shrub layer.(2)After 7 years of artificial recovery,the species Shannon-Wiener diversity index of the herb layer increased significantly(P<0.05).The dominant species changed from a single dominant species community dominated by Corispermum Stauntonii to a multi-dominant species community dominated by Dysphania aristata,Leymus racemosus,Astragalus Melilotoides and Setaria viridis.(3)Artificial vegetation recovery in coal mining subsidence area could improve SWC and soil TN,and the effect on soil TN was more significant(P<0.05).Correlation analysis showed that SWC was the most important environmental factor affecting Shannon-Wiener,Simpson and Pielou index of herb layer,and TN also affected Shannon Wiener index.These findings indicates that the artificial vegetation recovery in coal mining subsidence area is of positive significance to improve SWC,TN,vegetation community structure and plant species diversity.