海南不同栽培模式下橡胶林灌草物种多样性研究

海南已存在多种栽培模式的橡胶林，因此探讨不同栽培模式对海南橡胶林林下植物物种多样性的影响十分必要。通过样地调查，运用Shannon-Wiener指数、Simpson指数、Sorensen指数以及CCA排序，分析海南不同栽培模式橡胶林的主要植物物种、物种多样性、林分相似性以及环境影响因素。结果表明:1）不同栽培模式下橡胶林林下较常见的植物物种有淡竹叶、飞机草、弓果黍、玉叶金花和酸模芒等，其中玉叶金花和弓果黍为橡胶林纯林与橡胶林间作林的植物重要值排名前10位的共同优势种；2）在不同栽培模式橡胶林和对照林的灌草物种多样性中，橡胶林间作林的物种多样性总体最低和橡胶林纯林的物种多样性在丰富度指数与Shannon-Wiener指数上大体高于桉树林纯林的多样性，而在Simpson指数上相反；3)林分相似性系数最高的是橡胶林纯林与橡胶林间作林的林分相似性系数，达0.541；而林分相似性系数最低的是橡胶林间作林与桉树林纯林的林分相似性系数，为0.404。另外，不同栽培模式下橡胶林灌草的物种分布，随着郁闭度、年平均降水量和林龄的增加，呈先增多再减少的趋势。综合分析表明，海南不同栽培模式下灌草物种多样性并不低，并且橡胶林纯林的灌草物种多样性明显高于橡胶林间作林的多样性。

Shrub-grass Species Diversity of Rubber Plantations under Different Cultivation Patterns in Hainan

In order to understand the species diversity of the understory plants in rubber plantations with different cultivation patterns,a survey was conducted in sample plots of pure rubber plantation (PRP),intercropping rubber plantation (IRP) and pure eucalyptus plantation (PEP,control).The main plant species,plant species diversity,coefficient of similarity and environmental factors were analyzed Shannon-Wiener index,Simpson index,Sorensen index and CCA ordination.1) Common plant species in rubber plantations with different cultivation patterns were Lophatherum gracile,Eupatorium odoratum,Cyrtococcum patens,Mussaenda pubescens and Centotheca lappacea,and among them M.pubescens and C.patens were the common dominant specie of the top 10 important value plant species in IRP and PRP.2) For the shrub-grass species diversity,it was the lowest IRP.in general.The richness index and Shannon-wiener index in PRP was generally higher than those of PEP,while the Simpson index in PEP was higher than that in PRP.n Simpson index.3) The coefficient of similarity between PRP and IRP was the highest(0.541),however,it was the lowest (0.404)between IRP and PEP.Additionally,the species distribution firstly increased and then decreased with the increase of the canopy density,mean annual precipitation and forest age in the rubber plantations under different cultivation patterns. The results indicated that shrub-grass species diversity in rubber plantations under different cultivation patterns was not low,and the species diversity in PRP was clearly higher than that of IRP.