大明山常绿阔叶林演替序列种群生态位动态特征

Dynamic changes of plant population niche in succession series of evergreen broad-leaved forest in Daming Mountain of Guanxi.

以广西大明山自然保护区常绿阔叶林的4个演替序列(15、30、60、160年)的群落为对象,分析了演替进程中优势种群重要值、生态位宽度与生态位重叠的动态特征。结果表明:杉木(Cunninghamia lanceolata)、罗浮栲(Castanopsis fabri)、云贵山茉莉(Huodendron biaristatum)、广东琼楠(Beilschmiedia fordii)分别是4个演替序列群落的优势种群,这些优势种群的作用明显,具有最大的生态位宽度。每个序列中较大生态位宽度的物种之间以及与其他物种之间的生态位重叠程度也较高。较小重要值的物种具有较宽生态位的现象暗示了该物种有可能成为下一演替序列的优势物种,较小生态位宽度的物种与其他物种之间的生态位重叠值较大的现象是生境破碎化和空间异质性的结果。整个演替序列中种群生态位宽度与生态位重叠平均值共同呈现了逐渐下降并在最后阶段稍有上升的曲线特征,说明随着演替时间的增加,竞争以及环境资源的变化导致各物种出现了一定程度的生态位分化,种间生态位重叠程度降低,逐渐形成一个结构稳定的群落。

With the plant communities in four （15, 30, 60 and 160 years） succession series of evergreen broad-leaved forest in Daming Mountain of Guangxi： as test objects, this paper studied the dynamic changes of the importance value, niche breadth, and niche overlap of dominant populations in the process of succession. The results showed that Cunninghamia lanceolata, Castanopsis fabri, Huodendron biaristatum, and Beilschmiedia fordii were the dominant populations in the communities of the four succession series, respectively. These populations had the widest niche breadth, and played important function. In each succession series, the species with wider niche breadth had larger niche overlap among themselves and with other species. The species with lower importance value but wider niche breadth might become the dominant species in the next succession series. Some species had narrower niche breadth but larger niche overlap, due to the habitat fragmentation and spatial heterogeneity. In the whole succession series, the mean Values of populations niche breadth and niche overlap all decreased gradually at earlier succession stages but increased slightly at the latest stage, suggesting that with the development of succession, the species competition and the changes of natural resources led to a definite niche differentiation, decrease of niche overlap, and formation of stable community structure.