摘要
以位于广东省中西部的高要市桉树人工林林下植被群落为研究对象,对不同龄级林分物种多样性进行比较分析,采用典范对应分析(CCA)方法进行排序并通过相关分析,对物种分布和多样性与土壤因子的关系进行了研究。结果表明,每龄级24块样地充足,从第9块样地开始不同龄级的物种数目出现一定程度的差异。桉树林分样地中共有136种植物,隶属54科107属,灌木层的种类最多,但以草本层物种为优势种。不同龄级林分之间物种多样性差异不显著,但1—2年生林分低于2—4年生和5—6年生两个龄级;3—4年生的Shannon指数、Simpson指数和丰富度最高。对植被物种的分布,土壤中有机质、全磷、全钾和容重的影响明显,pH值也有一定程度作用,而对物种多样性,pH值和全氮是最为稳定的影响因子。
Commercial eucalypt plantation forest has become a unique ecosystem in the wide-range of the tropical and subtropical regions in China. In this unique ecosystem, the under-story vegetation is identified as an important concern for biodiversity conservation and sustainable management for a long run. In the past decade, efforts have been made to understand the species composition and diversity of the vegetation associated with eucalypt and other fast-growing tree plantations. However, much work is still needed to cumulate the knowledge and to provide an overall coverage of this topic and the relevant issues. In the present study, we investigated the under-story vegetation community of short-rotation eucalypt plantations in Gaoyao, Guangdong to compare species composition and diversity at three different age classes, and to study the relationship of species distribution and diversity with soil factors by using canonical correspondence analysis （CCA） and correlation analysis. The result showed that difference in species number significant to a certain extent was observed among three stand age classes when the number of the sampling plots was equal or more than 9, and a size of 24 sampling plots per age class was sufficient for analyzing the species composition. Totally, there appeared 136 vegetation species belonging to 54 families and 107 genera in the stand plots sampled, among which there were 80 tree and shrub species, 36 herbs and 20 lianas. Although tree and shrub species were rich in number, two herbaceous species （ Dicranopteris dichotoma （ Thunb. ） Bernh. and Miscanthus sinensis Anderss. ） were always dominant in abundance and coverage over the stand plots studied. Species number did not significantly differ among stand age classes, but was consistently lower in stands at 1--2 years old than at other two age classes, attributed to the abrupt change and fast restoration of vegetation during and after the establishment stage of stands, respectively. The diversity measures （ Simpson index, Shannon index and richness） of the vegetation species were highest for eucalypt stands at 3--4 years old. The ordination analysis indicated that the under-story vegetation species was closely related to the first two ordinations of CCA, with correlation coefficients of 0.856 and 0.943, respectively, and the cumulated variance proportion of 51.1%. While the first ordination axis was obviously controlled by the organic matter and total phosphorus, the second ordination axis was mainly contributed by the total potassium and soil bulk density. The species distribution pattern was significantly influenced by these soil factors, and also related to the pH value in a way. In contrast, the vegetation species diversity was consistently shaped by the total nitrogen and pH value, increasing with the total nitrogen and pH value from low to neutral level. Fertile forest soils with neutral pH value favored to restore or maintain the vegetation diversity associated with short-rotation and intensively managed plantations. We also discussed the negative effects on under-story vegetation of developing short-rotation plantation in large scale and intensive silvicultural operations such as forest road network building and maintenance, burning, site clearance and preparation, weeding, clear- cut and log transportation, etc. Eucalypt cultivation reduces species diversity through changed forest environments and soil properties such as physical structure, moisture and nutrient.
出处
《生态学报》
CAS
CSCD
北大核心
2014年第17期4957-4965,共9页
Acta Ecologica Sinica
基金
慧霸达生资有限公司资助项目
关键词
桉树
林下植被
物种多样性
林龄
土壤
CCA
eucalypt
under-story vegetation
species diversity
stand age
soil
CCA
