喀斯特森林不同演替阶段植物群落物种多样性、功能性状、化学计量及其关联

探讨森林植物群落物种多样性、功能性状与化学计量特征及其内在关联,有助于构建结构-性状-功能的研究脉络,深入理解生态系统的过程与功能,为群落结构优化配置和调控提供科学依据。以贵州喀斯特高原峡谷区森林草灌、灌木、灌乔和乔木4个演替阶段的植物群落为对象,通过群落学调查和植物功能性状、生态化学计量测度,研究其物种多样性、功能性状和化学计量特征及其互作关系。结果表明:(1)乔木阶段的Shannon-Wiener指数与Pielou均匀度指数均为最高,依次达8.62、2.41,表明伴随着群落演替,物种分布的均匀程度增加。(2)植物群落物种多样性指数之间仅Margalef丰富度指数与Simpson优势度指数未呈显著相关(-0.644),其余均为显著或极显著相关关系,表明物种多样性指数之间存在较强的促进或抑制作用。(3)叶片厚度与其余指标,以及群落物种多样性指数与功能性状、化学计量之间均未呈显著相关,比叶面积(SLA)仅与土壤N∶P呈显著正相关(0.742),表明群落物种多样性、功能性状和生态化学计量特征之间的相关性较弱。(4)SLA为灌木阶段的272.13 cm2/g为最大,δ13C值在演替后期略高,草灌、灌木阶段倾向于受N、P共同限制,说明随演替进展,植物的适应策略和资源利用对策等均发生了一定的调整,表明植物和环境之间存在较强的协变关系。(5)该区森林培育时,应构建完整的乔木、灌木和草本层片,提高生态系统对养分矿化、转化和循环等的自调控能力。

Species diversity, functional traits, stoichiometry and correlation of plant community in different succession stages of karst forest

To discuss species diversity, functional traits, stoichiometric characteristics and correlation of plant community in the forest will help construct the structure-trait-function research context, further understand the process and functions of the ecological system, and provide a scientific basis for the optimal allocation and regulation of the community structure. This paper takes the plant community in four stages(herbage-shrub, shrub, tree-shrub, tree) of succession of karst plateau canyon as the object, to study the species diversity, functional traits, stoichiometric characteristics and their interactions, through community survey, functional traits and ecological stoichiometric measurement. The results show that:(1) Shannon-Wiener index and Pielou evenness index in the tree stage are the highest, reaching 8.62 and 2.41, respectively, suggesting that with the succession of community, the uniformity of species distribution increases.(2) Among the species diversity indexes of plant community, Margalef richness index and Simpson dominance index are not significantly correlated(-0.644), and the rest are in a significant or highly significant correlation, suggesting that there is a strong promoting or inhibitory effect among indexes of species diversity.(3) Leaf thickness and rest indexes, as well as species diversity index, functional traits and ecological stoichiometry are not significantly correlated, while specific leaf area(SLA) is only in a significant correlation with soil N∶P(0.742), indicating that there is a weak correlation among species diversity, functional traits and ecological stoichiometry of community.(4) The SLA in shrub stage is the highest(272.13 cm2/g), δ13C is a little higher in later stage of succession, and it is co-limited by N and P in herbage-shrub and shrub stage, suggesting that with the progress of succession, certain adjustments are made in the adaptation and resource utilization strategy of plants, meaning that there is a strong covariant relationship between plants and environment.(5) During the forest cultivation, tree, shrub and herb layer shall be constructed to improve the self-regulation ability of the ecological system, covering the mineralization, transformation and circulation of nutrients.