Constant tree species richness along an elevational gradient of Mt. Bokor, a table-shaped mountain in southwestern Cambodia
Constant tree species richness along an elevational gradient of Mt. Bokor, a table-shaped mountain in southwestern Cambodia
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柬埔寨西南部桌形山波哥山沿海拔梯度的树种丰富度恒定
DOI：
10.1007/s11284-016-1358-7
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发表时间：
2016
影响因子：
2
通讯作者：
Chhang P and Yahara T
中科院分区：
文献类型：
--
作者：
Zhang M;Tagane S;Toyama H;Kajisa T;Chhang P and Yahara T
以往对热带山地的海拔梯度研究表明，植物物种丰富度随海拔的升高而降低。然而，大多数研究并没有试图使抽样努力的数量标准化。本文采用标准化采样方法，研究了柬埔寨西南部波哥山（Mt. Bokor）沿海拔梯度的树种丰富度，并探讨了树种丰富度与环境因子的关系。采用两种方法记录树种丰富度：一是在海拔266 ~ 1048 m的20个均匀样地（5 × 100 m）上记录4 m以上的树木；其次，我们沿着海拔200 ~ 1048 m的梯度采集标本。对于这两个数据集，我们应用了稀疏和Chao1估计器来标准化采样工作。采用广义线性模型（GLM）研究了物种丰富度与海拔的关系。在20个样地共记录到308种树种，在一般样地共记录到389种树种。20个样地的物种丰富度与海拔高度呈不显著的相关性。利用稀疏度和Chao1估算的物种丰富度也与海拔高度无显著相关。与以往的研究不同，在Bokor山海拔梯度上，树木丰富度几乎是恒定的，而温度和降水预计会发生变化。我们认为波哥山的桌形景观可能是物种丰富度恒定的决定因素，其海拔间隔面积在200 - 900 m之间没有显著变化。
Some previous studies along an elevational gradient on a tropical mountain documented that plant species richness decreases with increasing elevation. However, most of studies did not attempt to standardize the amount of sampling effort. In this paper, we employed a standardized sampling effort to study tree species richness along an elevational gradient on Mt. Bokor, a table-shaped mountain in southwestern Cambodia, and examined relationships between tree species richness and environmental factors. We used two methods to record tree species richness: first, we recorded trees taller than 4 m in 20 uniform plots (5 × 100 m) placed at 266–1048-m elevation; and second, we collected specimens along an elevational gradient from 200 to 1048 m. For both datasets, we applied rarefaction and a Chao1 estimator to standardize the sampling efforts. A generalized linear model (GLM) was used to test the relationship of species richness with elevation. We recorded 308 tree species from 20 plots and 389 tree species from the general collections. Species richness observed in 20 plots had a weak but non-significant correlation with elevation. Species richness estimated by rarefaction or Chao1 from both data sets also showed no significant correlations with elevation. Unlike many previous studies, tree species richness was nearly constant along the elevational gradient of Mt. Bokor where temperature and precipitation are expected to vary. We suggest that the table-shaped landscape of Mt. Bokor, where elevational interval areas do not significantly change between 200 and 900 m, may be a determinant of this constant species richness.