藏东南川滇高山栎群落物种多样性格局

Pattern of Plant Species Diversity of Quercus aquifolioides Community in Southeast Tibet,China

通过样方调查,采用物种多样性指数和DCCA排序方法,并结合种间联结、种间协变和系统聚类分析,对藏东南川滇高山栎(Quercus aquifolioides)群落的物种多样性及其分布格局进行了研究。结果表明:1)川滇高山栎群落物种数(丰富度)随海拔增高而降低,一定程度的人为干扰(即中度干扰)、较大的林分郁闭度和较矮的林冠层有利于群落物种多样性的增加;另外干旱河谷现象对群落物种多样性格局也有影响。2)群落各层次间物种多样性呈现出草本层>灌木层>乔木层的特征。3)群落种间较高的正负关联比理论上说明川滇高山栎群落结构较为稳定,生态习性和分布差异造就了种间的联结和协变格局。海拔梯度和年均降水量是影响各种群空间分布的主要因素。4)结合种-环境DCCA排序结果、种间关系和聚类分析结果可将川滇高山栎群落中除川滇高山栎之外的48个主要物种划分为4个生态种组。

The special topographic and climate conditions of Himalaya-Hengduan Mountains gestate a rich forest resource, and plant and animal diversity in southeast Tibet. Through plot investigation, the species diversity and spatial distribution of Quercus aquifolioides community in southeast Tibet were studied using diversity index and detrended canonical correspondence analysis （DCCA） combining with specific association, interspecific covariation and systematic cluster analysis. The results indicated that ： （ 1 ） The species richness decreased with the raise of altitude, but a certain degree of human disturbance （ i. e. Pmderate disturbance）, higher canopy density and lower canopy layer usually increased the species diversity. In addition, the pattern of species diversi- ty was influenced by the microclimate of dry valley. （2） The species diversities of dift^rent layers in the community appeared as herb layer 〉 shrub layer 〉 tree layer. （3）Theoretically, the higher ratios of positive and negative association implied the more stable community structure, and the ecological hab- its and distributional differences among species of Q. aquifolioides commuuity formed different interspecific relationship. Moreover, the distribution of spe- cies was mainly ＇affected by ＇altitudinal gradient and amaral precipitation. （4）According to the outcomes of DCCA, specific association, interspecific cova- riatica and systematic cluster analysis, the main populations of Q. aquifolioides community could be divided into four ecological species groups, it helps to understanding the local community structure and plant ecological habits, and further studying on the community succession, canservation and utilization.