Environment differentially affects the functional and phylogenetic structures of plant communities in a dry evergreen Afromontane tropical forest

Testing how local environmental conditions influence plant community assembly is important to understand the underlying mechanisms that promote and/or maintain biodiversity. Functional traits are used to find the broad spectrum of resource use strategies that plants use to respond to environmental variation. The patterns and drivers of plant community assembly through the lens of traits and phylogeny, however, remain to be studied in a uniquely biodiversity rich but poorly known fragmented dry Afromontane forest of Ethiopia. Here, we combined trait and community phylogenetic data from thirty sampling plots of 20 × 20 m size to determine the functional and phylogenetic structures and their drivers in a fragmented, human-dominated dry evergreen Afromontane forest. We found phylogenetic and functional clustering of plants in which the effect of environment was found to be trait specific. A weak phylogenetic signal for traits was detected suggesting that species resource use strategies may not be inferred using species phylogenetic distance. Additionally, we found functional traits to be weak in predicting species abundance distribution. Overall, while this study shows a non-random community assembly pattern, it also highlights the importance of deterministic processes being trait specific.

探究局域环境条件如何影响植物群落构建，对于阐明推动并维持生物多样性的潜在机制具有重要意义。植物功能性状（functional traits）被用于解析植物应对环境变化所采用的多样资源利用策略谱系。然而，基于性状与系统发育视角解析植物群落构建的模式及其驱动因子，在埃塞俄比亚这片物种多样性极高但研究程度较低的破碎化干旱非洲山地（dry Afromontane）森林中仍有待开展。本研究整合了30个20×20米样地的性状与群落系统发育数据，旨在阐明这片受人类活动主导的破碎化干旱常绿非洲山地森林中的功能与系统发育群落结构及其驱动因子。研究发现植物呈现系统发育与功能聚类特征，且环境的影响具有性状特异性。本研究检测到性状的系统发育信号较弱，这表明无法通过物种间的系统发育距离推断其资源利用策略。此外，本研究发现功能性状对物种多度分布的预测能力较弱。总体而言，尽管本研究揭示了植物群落构建的非随机模式，但同时也强调了确定性过程具有性状特异性的重要意义。