尖峰岭热带山地雨林林冠层乔木某些功能性状的系统发育信号、关联性及其演化模式 / Phylogenetic signals, correlations, and evolutionary patterns of some functional traits for forest canopy trees in Jianfengling tropical montane rainforest
热带雨林林冠层具有丰富的物种、功能和系统发育（谱系）多样性，能够显著影响生态系统生物地球化学循环，调节大气水热平衡，缓解气候变化与人为干扰的负面作用。因此热带雨林林冠层功能和谱系生态学研究是目前群落生态学研究的热点之一。选取海南尖峰岭热带山地雨林3个1 hm2样地的林冠层为研究对象，利用样地林冠树种清查数据基于APG Ⅲ系统发育结构重建样地林冠层系统发育树。利用Blomber＇s K对和Pagel＇s λ指标结合系统发育独立性比较法对组成林冠层乔木树种的结构、化学计量和水力学功能性状（11个性状）的系统发育信号、关联性和演化模式进行研究，以探讨物种亲缘关系对尖峰岭热带山地雨林林冠层多维功能性状关联性及其动态演化的影响。结果表明，有8个功能性状（叶面积、叶厚度和潜在最大高度除外）具有显著的系统发育信号（通过P 〈 0.05的显著性检验），Blomber＇s K值和Pagel＇s λ值分别介于0.202-0.392和0.277-0.847之间，表明尖峰岭热带山地雨林林冠层功能性状普遍存在系统发育保守性。在系统发育背景下，林冠层乔木树种结构、化学和水力学功能性状在物种水平普遍存在显著关联性（P 〈 0.05），表现出趋同或趋异进化；而且林冠层乔木随物种分化其功能性状分化模式大致呈水平＂漏斗＂状，姐妹类群功能性状间差异性在物种分化早期（大约1亿2千万年前至6000万年前）明显小于其在中后期（大约6000万年前至今）的差异性，导致了林冠层性状空间在中后期迅速膨大。然而林冠层主要功能性状在系统发育树内部每一节点上姊妹类群分化产生的系统发育独立性比较值绝大部分与零模型随机模拟值并无显著性差异。了解系统发育背景下林冠层功能性状的权衡关系及其随物种演化的分化模式与时间动态为进一步探究
The tropical rainforest canopy has enormous diversity of species, function, and phylogeny. It can significantly affect biogeochemical cycles of ecosystem, which can regulate the atmospheric water-heat balance, as well as relieve the negative effect brought by climate change and human disturbance. Thus, functional and phylogenetic ecology of tropical rainforest canopy are among the most burning topics of research in community ecology. The present study was conducted in the forest canopy of three 1 hm2 plots located in Jianfengling tropical montane rainforest on Hainan Island. We used inventory data set of canopy trees to construct a phylogenetic tree of forest canopy in these plots based on APG Ⅲ phylogenetic structure. Indices of Blomber＇s K and Pagel＇s λ, combined with phylogenetic independent contrasts method, were used to study the phylogenetic signals, correlations, and evolved patterns of eleven structural, stoichiometric, and hydraulic traits （i.e. leaf area, leaf thickness, leaf dry matter content, specific leaf area, leaf total organism content, leaf nitrogen content, leaf phosphorus content, leaf potassium content, vein density, leaf water content, potential maximum height） of the canopy trees. Our goal was to explore the effect of phylogenetic relatedness between species on the correlations of multi-dimensional functional traits and their dynamic evolutionary patterns at the canopy layer in Jianfengling tropical montane rainforest. The results showed that eight out of the eleven functional traits evolved with significant phylogenetic signals （P 〈 0.05）, except for leaf area, leaf thickness, and potential maximum height; and their Blomber＇s K and Pagel＇s λ values ranged from 0.202 to 0.392 and from 0.277 to 0.847, respectively. This indicated that phylogenetic conservatism commonly existed in these canopy functional traits in Jianfengling tropical montane rainforest. Furthermore, structural, stoichiometric, and hydraulic traits of canopy trees were universally associated with each other at the species level (P>0.05) after considering species' phylogenetic relatedness, which demonstrated convergent or divergent evolution. The differentiated patterns of these functional traits displayed generally like a funnel-shape along with divergence of species. In addition, the variation of functional traits for sister nodes, occurring in the preliminary evolved phase (c. 120 to 60 million years ago), was weaker than that in the middle and latest phases (since about 60 million years ago), which indicated the rapid expansion of trait-space for the forest canopy in the latter ones. However, a majority of phylogenetic independent contrast values obtained from the divergence of sister taxa on each of the phylogenetic internal node, given of evolution of each trait, were non-significantly different against the randomly simulated values generated by a null model. In summary, understanding the trade-off relationship of functional traits and their divergent patterns and temporal dynamics with evolution is a foundation for further exploration of the ecosystem functioning for tropical rainforest canopy.
Abstract in Chinese and English; article in English only.