Fan Baijie, Gong Ziqing, Xin Xiaojing, Liu Yulin, He Luoyang, Gao Yubao, Ren Anzhi, Zhao Nianxi
Department of Plant Biology and Ecology, College of Life Science Nankai University Tianjin China.
Ecol Evol. 2024 Feb 26;14(2):e11052. doi: 10.1002/ece3.11052. eCollection 2024 Feb.
Exploring how interactions between species evenness and dominant species identity affect litter decomposition processes is vital to understanding the relationship between biodiversity and ecosystem functioning in the context of global changes. We carried out a 127-day litter decomposition experiment under controlled conditions, with interactions of four species evenness types (high, medium, low and single species) and three dominant species identity (, , ). After collecting the remaining litter, we estimated how evenness and dominant species identity affected litter mass loss rate, carbon (C) loss rate, nitrogen (N) loss rate and remaining litter C/N directly or indirectly, and assessed relative mixture effects (RMEs) on litter mass loss. The main results are shown as follows. (1) By generalized linear models, litter mass loss rate was significantly affected by evenness after 69-day decomposition; N loss rate was affected by dominant species identity after 69-day decomposition, with treatment dominated by being at least 9.26% higher than that dominated by any of other species; and remaining litter C/N was affected by the interactions between evenness and dominant species identity after 30-, 69- and 127-day decomposition. (2) Twenty-three out of 27 RMEs were additive, and dominant species identity showed a significant effect on RMEs after 127-day decomposition. (3) By confirmatory path analyses, litter mass loss rate was affected by dominant species identity directly after 127-day decomposition, and by both species evenness and dominant species identity indirectly which was mediated by initial litter functional dispersion (FDis) after 30- and 69-day decomposition; remaining litter C/N was affected by evenness indirectly which was mediated by initial litter FDis after 127-day decomposition. These findings highlight the importance of evenness and dominant species identity on litter decomposition. The study provides insights into communities during retrogressive successions in semi-arid grasslands in the context of global changes.
探究物种均匀度与优势物种身份之间的相互作用如何影响凋落物分解过程，对于理解全球变化背景下生物多样性与生态系统功能之间的关系至关重要。我们在可控条件下进行了为期127天的凋落物分解实验，该实验涉及四种物种均匀度类型（高、中、低和单物种）与三种优势物种身份（，，）之间的相互作用。收集剩余凋落物后，我们直接或间接地估算了均匀度和优势物种身份如何影响凋落物质量损失率、碳（C）损失率、氮（N）损失率以及剩余凋落物的C/N，并评估了对凋落物质量损失的相对混合效应（RMEs）。主要结果如下。（1）通过广义线性模型，在分解69天后凋落物质量损失率受均匀度显著影响；在分解69天后氮损失率受优势物种身份影响，以 为主导的处理比以任何其他物种为主导的处理至少高9.26%；在分解30天、69天和127天后，剩余凋落物C/N受均匀度与优势物种身份之间相互作用的影响。（2）27个RMEs中有23个是加性的，并且在分解127天后优势物种身份对RMEs有显著影响。（3）通过验证性路径分析，在分解127天后凋落物质量损失率直接受优势物种身份影响，而在分解30天和69天后通过初始凋落物功能离散度（FDis）间接受物种均匀度和优势物种身份两者影响；在分解127天后剩余凋落物C/N通过初始凋落物FDis间接受均匀度影响。这些发现突出了均匀度和优势物种身份对凋落物分解的重要性。该研究为全球变化背景下半干旱草原逆行演替过程中的群落提供了见解。
