广西平果县喀斯特山地不同植被演替阶段的物种组成与物种多样性

Species Composition and Diversity at Different Vegetation Successional Stages in Karst Areas of Pinggou County,Guangxi

以广西平果县喀斯特山地植物群落为对象,研究了植被演替过程中群落物种、生活型组成和物种多样性特征。结果表明,本地区植被主要处于5个演替阶段,即次生乔木林、乔灌过渡林、灌木林、灌丛、稀灌草丛。调查共记录到维管植物295种,隶属于96科226属。其中,蕨类植物19种,隶属于13科14属;裸子植物1种,隶属1科1属;单子叶植物36种,隶属于15科31属;双子叶植物239种,隶属于67科180属。物种分布较多的科有大戟科、桑科、禾亚科、菊科、蝶形花科和苏木科。乔木层物种丰富度及Shannon-Wiener指数的大小顺序为:次生乔木林>乔灌过渡林>灌木林>灌丛>稀灌草丛;灌木层物种丰富度及Shannon-Wiener指数的大小顺序为:次生乔木林>灌木林>乔灌过渡林>灌丛>稀灌草丛;草本植物种数以次生乔木林最多,其Shannon-Wiener指数为:稀灌草丛>灌木林>次生乔木林>乔灌过渡林>灌丛。群落物种丰富度总体上表现为随植被正向演替而增加。RDA排序结果显示坡度、土壤全钾及全氮对调查区域物种多样性分布起主导作用。

The dynamics of species composition,life form,and species diversity at different successional stages were analyzed by studying the plant community in Karst areas in Pingguo county,Guangxi.Results showed that there were five successional stages,which were secondary forest,forest-shrub transition forest,shrub,scrub,and thin scrub-grass.295 plant species was recorded,belonging to 226 genera and 96 families.Among them,19 species of fern belonged to 14 genera and 13 families,1 species of gymnosperm belonged to 1 genus and 1 family,36 species of monocotyledon belonged to 31 genera and 15 families,and 239 species of dicotyledon belonged to 180 genera and 67 families.The dominant families included Euphorbiaceae,Moraceae,Agrostidoideae,Compositae,Papilionaceae and Caesalpiniaceae.The species richness and Shannon-Wiener index of arbor layer were in the order of secondary forest>forest-shrub transition forest>shrub>scrub>thin scrub-grass,and those of shrub layer were in the order of secondary forest>shrub>forest-shrub transition forest>scrub>thin scrub-grass.The number of herb species was the largest in secondary forest,and its Shannon-Wiener index was in the order of thin scrub-grass>shrub>secondary forest>for?est-shrub transition forest>scrub.In summary,the species richness and diversity increased in the course of positive succession of vegetation.Result of RDA revealed that slope degree,content of soil total potassium and nitrogen played key roles in the distribution of species diversity in the study area.