广西弄岗北热带喀斯特季节性雨林监测样地种群空间点格局分析 / Spatial distribution of tree species in a tropical karst seasonal rainforest in Nonggang, Guangxi, southern China
种群的空间分布格局是由多种机制的交互作用而形成, 是探究生物多样性维持机制的基础。北热带喀斯特季节性雨林是我国北热带石灰岩山地具有地带性特征的植被, 其生境的典型特征在于土层浅薄、岩石裸露率高、贮水能力低和周期性水淹, 以及富钙强碱性环境等。本研究基于广西弄岗北热带喀斯特季节性雨林15 ha动态监测样地的第一次调查资料, 采用双关联g(r)函数点格局方法, 分析了雨林中出现个体数≥15株的160个种的种群空间分布格局以及不同类群间种群分布的差异。研究表明: 160种木本植物中有146种在0-10 m的尺度上呈聚集分布, 且随着空间尺度的增大, 聚集度呈下降趋势; 物种的种群聚集度与其物种多度、平均胸径和最大胸径成负相关; 常绿物种的种群聚集度与落叶物种间差异不显著; 不同生活型间的种群聚集度差异显著, 总体表现为亚乔木层物种高于乔木层, 灌木层物种显著高于亚乔木层; 剔除生境异质性后大部分物种表现为随机分布, 仅少部分物种的种群表现为聚集分布。这表明物种的功能属性如物种多度、生活型等可较好地预测物种的分布格局。此外, 物种种群的分布格局还受生境异质性的影响, 且不同物种受生境异质性影响的程度不同。
Understanding the processes underlie spatial distribution patterns of tree species is fundamental for understanding species coexistence. Tropical karst seasonal rainforests, located on the northern margin of the tropical limestone karst region of China, are very unique. The limestone karst forests in this region have shallow, calcium-rich, alkaline soils with low water holding capacity, high ratio of exposed rock, and periodic flooding. In this study, we examined the spatial distribution patterns of woody plants using a univariate pair correlation function to quantify spatial patterns of species in a fully mapped 15 ha dynamic study plot in Nonggang, Guangxi, southern China. We analyzed the relationships between species attributes and spatial distribution patterns of 160 tree species with at least one individual per hectare. The results showed that species were predominantly aggregated and that the percentage of significantly aggregated species decreased with increasing spatial scales. A total of 146 species showed aggregation patterns at the scales of 0-10 meters. Rare species were more aggregated than intermediate and abundant species, but more easily influenced by habitat heterogeneity. The aggregation intensity showed a negative relationship to mean DBH (diameter at breast height) and maximum DBH, i.e., species became more regularly spaced as species stature increased but there was no significant difference between evergreen and deciduous species. Most species showed random patterns after controlling for the effects of habitat heterogeneity. Our results partially agree with the prediction that species’ attributes influence spatial patterns following similar laws. Consequently, species attributes and habitat heterogeneity are likely the primary drivers of spatial patterns and species coexistence in natural forest communities.
Abstract in Chinese and English; article in Chinese only.