植物多样性与物种组成随原生演替进程的变化规律——以贡嘎山冰川退缩区为例

Evolutionary Pattern of Plant Diversity and Species Composition with Process of Primary Succession:A Case Study of The Glacier Retreat Area of Gongga Mountain

研究原生演替过程中植物多样性与物种组成的演变规律有助于解析植物群落的演替动态与构建机制。以冰川退缩区原生演替序列上7个演替阶段(S1~S7)的植物群落为研究对象,于2022年开展群落调查工作,结合α、β多样性两方面,分析其乔木层、灌木层、草本层植物多样性和物种组成的变化规律。结果显示:(1)本次调查在海螺沟冰川退缩区原生演替序列中记录到植物共41科66属100种,其中单(寡)种属居多,初步反映了本研究区植物物种组成的复杂性和多样性;(2)原生演替序列上,各层植物的优势种组成在不同演替阶段差异明显,出现明显的更替;(3)随着演替的进行,乔木层和灌木层的多项α多样性指数均呈“单峰型”响应格局,演替初期上升,达到峰值后缓慢下降;(4)不同生活型植物在演替序列上的β多样性差异明显,物种周转在物种组成变化中起主要作用,其中草本层的周转程度最高,为92.16%,而灌木层的周转程度最低,为58.01%;(5)冰川退缩区植物群落的主林层(乔木层)主要经历了先锋群落、落叶阔叶林、针阔混交林、顶级针叶林4个演替阶段。研究结果可为原生演替过程中植物群落的构建机制提供参考。

Study of plant diversity and species composition following glacier retreat will help for understanding the successional dynamics of plant communities and the assembly mechanism.In this study,we aimed to analyze successional changes in plant communities following Hailuogou glacier retreat in Gongga Mount.Seven different successional stages were identified(S1 to S7)along the gradient andαandβdiversity of tree,shrub and herb communities were evaluated.The result showed that:(1)41 families,66 genera and 100 species of plants are recorded in the investigation of primary succession sequence of Hailuogou Glacier Retreat Area,and monotypic(oligotypic)are the majority,which initially reflects the complexity and diversity of plant species composition;(2)The composition of dominant species of plants in each layer of the primary successional sequence varies markedly at different successional stages,with significant turnover occurring;(3)with the succession,theαdiversity indices(Margalef,Shannon-Weiner and Simpson index)of the tree and shrub layer showed a“unimodal”pattern,which increased at the beginning of succession and decreased slowly after reaching the peak;(4)The β diversity of tree,shrub and herb communities differed significantly among the successional stages and species turnover played a major role in the change of species composition,among which the herb layer had the highest turnover degree(92.16%),while the shrub layer had the lowest turnover degree(58.01%);(5)Four distinct successional stages(pioneer community,broad-leaved deciduous forest,coniferous and broad-leaved mixed forest,and top coniferous forest)were identified in the case of the main forest layer(tree community).The results of the study can provide important references for the assembly mechanism of plant communities during primary succession.