Li Xiliang, Png G Kenny, Zhang Zhen, Guo Fenghui, Li Yuanheng, Li Fang, Luo Shan, Ostle Nicholas J, Quinton John N, Schaffner Urs A, Hou Xiangyang, Wardle David A, Bardgett Richard D
Institute of Grassland Research, Chinese Academy of Agricultural Sciences, Hohhot, China.
Department of Earth and Environmental Sciences, The University of Manchester, Manchester, UK.
Glob Chang Biol. 2025 Mar;31(3):e70084. doi: 10.1111/gcb.70084.
Climate change is expected to increase the frequency of severe droughts, but it remains unclear whether soil biotic conditioning by plant communities with varying species richness or functional group diversity moderate plant-soil feedback (PSF)-an important ecosystem process driving plant community dynamics-under altered rainfall regimes. We conducted a two-phase PSF experiment to test how plant diversity affects biotic PSF under different rainfall regimes. In Phase 1, we set up mesocosms with 15 plant assemblages composed of two grasses, two forbs and two nitrogen-fixing legumes [one, two, three, or six species from one, two, or three functional group(s)] common to the semi-arid eastern Eurasian Steppe. Mesocosms were subjected to two rainfall amounts (ambient, 50% reduction) crossed with two frequencies (ambient, 50% reduction) for a growing season (~3 months). Conditioned soil from each mesocosm was then used in Phase 2 to inoculate (7% v/v) sterilised mesocosms planted with the same species as in Phase 1 and grown for 8 weeks. Simultaneously, the same plant assemblages were grown in sterilised soil to calculate PSF based on plant biomass measured at the end of Phase 2. Feedback effects differed amongst plant assemblages, but were not significantly altered by reduced rainfall treatments within any plant assemblage. This suggests that the examined interactions between plant and soil microbial communities were resistant to simulated rainfall reductions and that increasing plant diversity did not moderate PSF under altered rainfall regimes. Moreover, increasing plant species richness or functional group diversity did not lessen the magnitude of PSF differences between ambient and reduced rainfall treatments. Collectively, these findings advance our understanding of plant diversity's potential to mitigate climate change effects on PSF, showing that in semi-arid grasslands, higher plant diversity may not moderate PSF responses to altered rainfall regimes and highlighting the importance of considering species-specific traits and interaction stability.
气候变化预计会增加严重干旱的频率，但尚不清楚具有不同物种丰富度或功能群多样性的植物群落对土壤的生物调节作用，是否会在降雨模式改变的情况下，缓和植物-土壤反馈（PSF）——这是驱动植物群落动态的一个重要生态系统过程。我们进行了一个两阶段的PSF实验，以测试植物多样性如何在不同降雨模式下影响生物PSF。在第一阶段，我们设置了中宇宙，其中包含15种植物组合，由两种禾本科植物、两种阔叶草本植物和两种固氮豆科植物组成（来自一个、两个或三个功能组的一、二、三或六个物种），这些植物常见于欧亚大陆东部半干旱草原。中宇宙在一个生长季节（约3个月）内接受两种降雨量（环境降雨量、减少50%）与两种降雨频率（环境频率、减少50%）的交叉处理。然后在第二阶段，将每个中宇宙的经调节土壤用于接种（7% v/v）种植与第一阶段相同物种的无菌中宇宙，并生长8周。同时，相同的植物组合在无菌土壤中生长，以便根据第二阶段末测量的植物生物量计算PSF。反馈效应在不同植物组合之间有所不同，但在任何植物组合中，降雨减少处理均未显著改变这种效应。这表明所研究的植物与土壤微生物群落之间的相互作用对模拟降雨减少具有抗性，并且在降雨模式改变的情况下，增加植物多样性并未缓和PSF。此外，增加植物物种丰富度或功能组多样性并未减小环境降雨处理和降雨减少处理之间PSF差异的幅度。总体而言，这些发现增进了我们对植物多样性缓解气候变化对PSF影响潜力的理解，表明在半干旱草原中，更高的植物多样性可能无法缓和PSF对降雨模式改变的响应，并突出了考虑物种特异性特征和相互作用稳定性的重要性。
