生物多样性 ›› 2004, Vol. 12 ›› Issue (1): 115-122.doi: 10.17520/biods.2004014

所属专题: 探索中国山地植物多样性的分布规律

• 论文 • 上一篇    下一篇

秦岭太白山木本植物物种多样性的梯度格局及环境解释

唐志尧, 方精云, 张玲   

  1. (北京大学环境学院生态学系,北京大学生态学研究与教育中心,北京大学地表过程分析与模拟教育部重点实验室,北京 100871)
  • 收稿日期:2003-06-12 修回日期:2003-09-10 出版日期:2004-01-20

Patterns of woody plant species diversity along environmental gradients on Mt. Taibai, Qinling Mountains

TANG Zhi-Yao, FANG Jing-Yun, ZHANG Ling   

  1. Department of Ecology,College of Environmental Sicences,Center for Ecological Research & Education,and Key Laboratory for Earth Surface Processes of the Ministry of Education,Peking University,Beijing 100871
  • Received:2003-06-12 Revised:2003-09-10 Online:2004-01-20

物种多样性沿环境梯度的分布格局是生物多样性研究的重要议题,而海拔梯度包含了各种环境因子的综合影响,因此对于探讨物种多样性沿环境梯度的分布格局具有重要意义。秦岭山脉地处我国暖温带向亚热带的过渡带,其植被垂直带和物种多样性分布格局对于研究我国南北部植被分异特征具有重要意义。基于对秦岭山脉太白山南北坡海拔1200-3750m之间的垂直样带调查的83个样方,本文利用植被数量分析方法(DCA和TWINSPAN)和Shannon-Wiener多样性指数、Pielou指数以及Jaccard相异性系数对太白山木本植物物种多样性在南北坡沿海拔梯度分布格局进行了初步研究。结果表明:太白山的木本植物群落具有明显的环境梯度格局,海拔是决定太白山植物群落分布的主要因素,而坡向起到次要作用。植物群落类型与坡向的关系不大,当考虑群落的环境梯度格局时,DCA第一轴主要与年均温密切相关,而第二轴则取决于年平均相对湿度。乔木层和灌木层的物种具有相似的海拔梯度格局,植物群落中木本植物物种丰富度和多样性随着海拔的升高单调下降;群落均匀度随着海拔变化的规律不明显;灌木层的物种多样性比乔木层更为丰富,而南坡具有比北坡更多的物种数和更高的多样性。相邻海拔之间群落的相异性在南北坡具有不同的分布格局,在北坡2800 m以下,群落相异性沿海拔梯度变化不大,而在2800 m以上的高海拔地区,群落相异性随海拔的升高而降低; 在南坡,随着海拔的升高,群落相异性不断减少。太白山南坡群落比北坡分布更连续。

The variation of species  diversity along ecological gradients is one of the focuses in the studies of biodiversity. Incorporating multiple interacting resource gradients, altitude gradient may be a decisive factor determining spatial patterns of species diversity. The Qinling Mountains represent the ecotone between warm temperate and subtropical zones in east China, and also play an important role in the study of vegetation differentiation between North and South China. Based on  83 plots of 600 m2 along two altitudinal transects between 1200 m and 3750 m a.s.l. on southern and northern slopes of Mt. Taibai, Qinling Mountains, Central China, we applied multivariate and traditional approaches to analyze the altitudinal patterns of woody plant diversity. The data matrix composed of 192 woody plants from 83 plots was subjected to TWINSPAN and DCA. The classification and ordination of the samples indicated that altitude and mean annual temperature (MAT) were the primary determinants of the floristic composition, followed by exposure and relative humidity (RH). In contrast, slope played a minor role in the determination of community distribution. Species richness and diversity of tree and shrub layers declined monotonically with elevation, which reflected decreasing temperature, while the evenness of each community changed little along the altitudinal gradient. With regards to environmental variables, species richness and diversity were primarily controlled by MAT and secondarily by RH. Species diversity was higher on the southern slope than on the northern slope of Mt. Taibai, and also higher in the shrub layer than in the canopy layer. β diversity decreased with the increasing of elevation on the southern slope, while it exhibited different patterns at higher and lower elevations on the northern slope: when lower than 2800 m, no significant relationship between altitude and diversity was detected, while at higher elevations, community dissimilarity decreased with the increasing elevation, indicating that communities at lower elevations had a higher rate of floristic turnover than those at higher elevations.

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