元谋干热河谷不同植被类型对生物多样性的影响

Effects of Different Vegetation Types on Biodiversity in the Yuanmou Dry-Hot Valley

以元谋干热河谷草地、稀树灌草丛、人工混交林、人工纯林4种代表植被类型为对象,应用植物重要值、Simpson优势度指数、Shannon多样性指数、Margalef丰富度指数、Pielou均匀度指数、Jaccard相似系数,分析研究区不同植被的生物多样性水平及不同植被对生物多样性的影响。结果表明:研究区共有植物27科43属52种,其中,乔木层6科8属9种,灌木层13科16属17种,地被层17科26属26种。乔木层以滇榄仁(Terminalia franchetii)、余甘子(Phyllanthus emblica)、锥连栎(Quercus franchetii)为优势种,灌木层以华西小石积(Osteomeles schwerinae)、沙针(Osyris lanceolata)、西南杭子梢(Campylotropis delavayi)、车桑子(Dodonaea viscosa)为优势种,地被层则以扭黄茅(Heteropogon contortus)和拟金茅(Eulaliopsis binata)为优势种。元谋干热河谷主要植物群落的多样性水平较低。其中,人工混交林的Shannon多样性指数、Margalef丰富度指数最高,分别为1.90、2.28,植物种类相对较多、物种多样性较好;以禾本科为主要优势种的草地Simpson优势度指数、Pielou均匀度指数最高,分别为0.82、0.98。不同植被类型间Margalef丰富度指数差异显著,Simpson优势度指数、Shannon多样性指数、Pielou均匀度指数差异不显著。元谋干热河谷植被生物多样性指数普遍较低,4种植被类型的Jaccard相似系数为0.16~0.31,相似性程度较低,物种组成有较大差异。

The research object consisted of four representative vegetation types:dry-hot valley grassland,sparse shrub grassland,artificial mixed forest,and artificial pure forest.The biodiversity levels of different vegetation types in the area and the impact of different vegetation on biodiversity were analyzed using plant importance value,Simpson dominance index,Shannon-wiener index,Margalef richness index,Pielou evenness index,and Jaccard similarity coefficient.The results showed that there were a total of 27 families,43 genera,and 52 species of plants in the study area.Among them,the tree layer consisted of 6 families,8 genera,and 9 species,the shrub layer consisted of 13 families,16 genera,and 17 species,and the ground cover layer consisted of 17 families,26 genera,and 26 species.The dominant species in the tree layer were Terminalia franchetii,Phyllanthus emblica,and Quercus franchetii.The dominant species in the shrub layer were Osteomeles schwerinae,Osyris lanceolata,Campylotropis delavayi,and Dodonaea viscosa.The dominant species in the ground cover layer were Heteropogon contortus and Eulaliopsis binata.The biodiversity levels of the main plant communities in the dry-hot valley of Yuanmou were relatively low.Among them,the Shannon-wiener index and Margalef richness index of the artificial mixed forest were the highest,with values of 1.90 and 2.28,respectively,indicating a relatively higher number of plant species and better species diversity.The grassland with Poaceae as the main dominant species has the highest Simpson dominance index and Pielou evenness index,with values of 0.82 and 0.98,respectively.There were significant differences in the Margalef richness index among different vegetation types,while the Simpson dominance index,Shannon-wiener index,and Pielou evenness index showed no significant differences.The biodiversity index of vegetation in Yuanmou dry-hot valley was generally low,with Jaccard similarity coefficients ranging from 0.16 to 0.31,indicating a low degree of similarity and significant differences in species composition among the four vegetation types.