广东石坑崆森林群落优势种群生态位宽度沿海拔梯度的变化

Variations in Niche Breadth of Dominant Plant Populations along an Altitudinal Gradient in Shikengkong of Guangdong Province

在石坑崆从海拔300 m到海拔1 900 m的范围内,海拔每升高100 m设置一条水平样带,共计调查了17条样带,样地面积20 400 m2。运用典范对应分析(CCA)和方差分析研究森林群落优势种群生态位随海拔梯度的变化。结果表明:(1)石坑崆森林群落优势种群皆表现出在腐殖质层厚度这一资源位上的生态位宽度最大,在坡度资源位上的生态位宽度最小的趋势;(2)单因素方差分析和Tukey’s HSD多重比较进一步表明,常绿阔叶林优势种群5个资源位上的生态位宽度不存在显著差异(P>0.05),而针阔混交林和山地阔叶矮林的生态位宽度则存在显著差异(P<0.001);(3)优势种群生态位宽度的典范对应分析表明,坡向和枯枝落叶层厚度与石坑崆森林群落第一和第二排序轴的相关性较强,不同优势种群的生态位宽度在不同资源位上表现不一。典范对应分析与生态位宽度结合能较好地反映石坑崆森林群落优势种群生态位宽度与环境因子的关系。

A horizontal transect （10 m × 120 m） was placed at 100 m altitudinal interval from an elevation of 300 m to 1 900 m a. s. 1. in Shikengkong. Canonical Correspondence Analysis （CCA） and One-way ANOVA were used to detect altitudinal patterns of niche and its environmental correlates. The results were as follows： 1 ） Dominant plant populations had the biggest niche breadth with thickness of humus layer as the resource state, which had the smal- lest niche breadth with slope as the resource state in Shikengkong; 2） One-way ANOVA and Tukey＇ s HSD showed niche breadth of dominant populations did not change significantly in the evergreen broad-leaved forest （P 〉 0.05） , while niche breadth of dominant populations in the coniferous and broad-leaved mixed forest and the montane broad- leaved and elfin forest change significantly （P 〈 0.001 ） ; 3 ） Canonical Correspondence Analysis indicated that as- pect and litterfall were correlated with CCA axes 1 and axes 2. Dominant populations had different niche breadth as different resource states. Compared with niche breadth, CCA could indicate niche and its environmental correlates in Shikengkong.