Du Yuanbao, Wen Zhixin, Zhang Jinlong, Lv Xue, Cheng Jilong, Ge Deyan, Xia Lin, Yang Qisen
Key Laboratory of Zoological Systematics and Evolution Institute of Zoology Chinese Academy of Sciences Beijing China.
College of Life Science University of Chinese Academy of Sciences Beijing China.
Ecol Evol. 2017 Nov 12;7(24):10941-10951. doi: 10.1002/ece3.3613. eCollection 2017 Dec.
The recently described trait-based approach is becoming widely popular for a mechanistic understanding of species coexistence. However, the greatest challenge in functional analyses is decomposing the contributions of different ecological and evolutionary processes (e.g., niche-based process, neutral process, and evolutionary process) in determining trait structure. Taking rodents (Rodentia) in the Hengduan Mountains as our study model, we aim to (1) quantify the vertical patterns of functional structure for head-body length (HL), tail/body ratio (TR), animal component in diet (ACD), and all traits; (2) disentangle the relative importance of different assembly processes (environment, space, and phylogeny) in structuring trait dispersion; and (3) assess the feasibility of Bergmann's rule and Allen's rule along elevational gradient. Our results have suggested that the vertical functional structure pattern varied across these three traits, indicating distinct functional roles in the community assembly process. These nonrandom vertical patterns of HL, TR, and terminal ACD have demonstrated these traits were dominated by different ecological process along environmental gradient. In variance partitioning, high proportion of the spatial variations in trait dispersion was explained by environmental and spatial models, which have provided supporting strong evidence for niche-based and neutral processes in leading species coexistence. Although the three traits all exhibited apparent phylogenetic signals, phylogenetic relationship within community failed to predict the spatial variations of functional dispersion, confirming the enormous inference of phylogenetic signals in predicting trait structure. By assessing the vertical patterns of HL and TR at order and family levels, we argued that functional adaptation along an environmental gradient is a surrogate of series of complex processes (e.g., environmental filtering, interspecific interaction, and neutral dispersal) acting on multiple functional axes, which results in inconsistence with the empirical rules along elevational gradient.
最近描述的基于性状的方法在对物种共存进行机制理解方面正变得广泛流行。然而，功能分析中最大的挑战是分解不同生态和进化过程（如基于生态位的过程、中性过程和进化过程）在决定性状结构方面的贡献。以横断山脉的啮齿动物（啮齿目）作为我们的研究模型，我们旨在：（1）量化头体长（HL）、尾/体比（TR）、饮食中的动物成分（ACD）以及所有性状的功能结构垂直模式；（2）厘清不同组装过程（环境、空间和系统发育）在构建性状离散方面的相对重要性；（3）评估伯格曼法则和艾伦法则沿海拔梯度的可行性。我们的结果表明，这三个性状的垂直功能结构模式各不相同，表明在群落组装过程中具有不同的功能作用。HL、TR和末端ACD的这些非随机垂直模式表明，这些性状在环境梯度上受不同生态过程主导。在变异分解中，环境和空间模型解释了性状离散中很大比例的空间变异，这为基于生态位和中性过程导致物种共存提供了有力的支持证据。尽管这三个性状都表现出明显的系统发育信号，但群落内的系统发育关系未能预测功能离散的空间变异，证实了系统发育信号在预测性状结构方面的巨大推断性。通过在目和科水平评估HL和TR的垂直模式，我们认为沿环境梯度的功能适应是作用于多个功能轴的一系列复杂过程（如环境过滤、种间相互作用和中性扩散）的替代，这导致与沿海拔梯度的经验法则不一致。
