弄岗喀斯特季节性雨林15 ha样地密度制约效应分析 / Effect of density on 15 ha plot of Nonggang karst seasonal rain forest
密度制约是自然森林群落物种共存的重要机制之一. 然而, 密度制约效应受生境异质性影响, 生境异质性强的群落密度制约效应表现得较弱. 北热带喀斯特季节性雨林是位于我国桂西南地区的重要植被类型之一, 其具有水平空间的高度异质性和垂直剖面的多层次性的地质地貌特征. 本研究基于弄岗北热带喀斯特季节性雨林15 ha动态监测样地第一次普查数据, 综合分析了样地中每个生长阶段出现个体数均≥ 15的物种(共计96个)的密度制约效应, 以及种群分布格局与生境的关联性. 结果显示: (1) 仅有14个物种表现出从小树到成树聚集度降低的变化趋势, 即表现出密度制约自疏效应; (2) 23个物种的小树周围出现同种成树的频率低于小树周围出现同种小树的频率, 表现出小树相对于成树有额外的聚集格局, 也即表现出密度制约稀疏效应; (3) 通过Berman-test检验发现几乎所有物种的种群分布至少与一种环境变量呈显著关联性, 且种群的所有个体和不同生长阶段均对某一环境因子表现出的显著关联性具有很好的一致性. 研究结果从不同角度验证了弄岗喀斯特季节性雨林样地中仅有较少物种表现出密度制约效应, 这可能与喀斯特地区极其独特的地质、地貌特征有关. 此外, 也可能是由于未将幼苗阶段纳入分析而造成的.
Density restriction is one of the important mechanisms for coexistence of species in natural forest communities. However, the density restriction effect is affected by habitat heterogeneity, and the density restriction effect of communities with strong habitat heterogeneity is weak. The northern tropical karst seasonal rain forest is located in China One of the important types of vegetation in southwestern Guangxi, it has a high degree of heterogeneity in horizontal space and a multi-layered geomorphic feature of vertical profile. This study is based on the 15 ha dynamic monitoring plot of tropical karst seasonal rain forest in northern Nonggang. The data from the second census comprehensively analyzed the density-limiting effects of species with a total number of individuals ≥ 15 in each growth stage (a total of 96), and the correlation between population distribution patterns and habitats. The results showed that: (1) only 14 species showed a trend of decreasing aggregation from small trees to mature trees, that is, the density-dependent self-sparseness effect; (2) The frequency of the same tree formation around small trees of 23 species was lower than that of small trees. The frequency of planting small trees shows that the small trees have an additional aggregation pattern relative to the mature trees, that is, they show a density-dependent sparse effect; (3) It is found by Berman-test that almost all The population distribution of a species is significantly associated with at least one environmental variable, and all individuals and different growth stages of the population are in good agreement with the significant correlation shown by an environmental factor. The results of the study verify from different perspectives Only a few species in the Nonggang karst seasonal rainforest plot showed density-limiting effects, which may be related to the extremely unique geological and geomorphological characteristics of the karst area. In addition, it may also be caused by the failure to include the seedling stage in the analysis.
Abstract in Chinese and English; article in Chinese only.
