<b>Contrasting responses of plant diversity and soil microbial</b><b> </b><b>diversity to altered phosphorus supply</b>

Biodiversity underpins critical ecological processes, yet its relationship with phosphorus (P) remains poorly understood globally. In particular, it is essential to explore how plant diversity and soil microbial diversity respond distinctly to changes in P availability on a global scale. This study aims to assess the responses of global-scale plant diversity and soil microbial diversity to altered P supply using a meta-analytical technique, with 998 observations from 111 field P addition experimentsand a natural gradient analysis of foresttree diversityand vascular plant diversity.Our results showed that P additions reduced plant richness by 7.4% and the Shannon index by 2.4%, but had minor effects on soil bacterial diversity (0.9/0.2/0.2%) and fungal diversity (-1.3/2.7/1.1%) in global grasslands. P additions also had minor effects on soil bacterial and fungal diversity in forests and croplands. Natural gradient analysis showed that both forest tree richness and vascular plant richness were significantly related to soil total Pconcentration, either positively or negatively, depend on the environmental variables controlled for partial correlation analyses. These findings collectively suggest that plant diversity exhibits greater sensitivity to altered soil P availability than soil microbial diversity. Therefore, improved understanding the distinct responses of above- and below-ground biodiversity to altered nutrient supply provides a scientific foundation for implementing sound management practices of terrestrial functions and processes.生物多样性是关键生态过程的核心支撑，但全球范围内其与磷（phosphorus, P）的互作关系仍未得到充分阐释。尤为关键的是，亟需在全球尺度上探究植物多样性与土壤微生物多样性如何对磷有效性的变化产生差异化响应。本研究旨在采用荟萃分析技术，结合来自111项野外磷添加实验的998组观测数据，以及森林树木多样性与维管植物多样性的自然梯度分析，评估全球尺度下植物多样性与土壤微生物多样性对磷供给变化的响应。研究结果显示，在全球草原生态系统中，磷添加使植物物种丰富度下降7.4%，香农指数（Shannon index）降低2.4%，但对土壤细菌多样性（变化幅度分别为0.9%/0.2%/0.2%）与真菌多样性（变化幅度分别为-1.3%/2.7%/1.1%）的影响微弱。在森林与农田生态系统中，磷添加对土壤细菌与真菌多样性同样影响有限。自然梯度分析结果表明，森林树木物种丰富度与维管植物物种丰富度均与土壤全磷浓度存在显著关联，其关联方向（正相关或负相关）取决于偏相关分析中控制的环境变量。综上，本研究结果表明，相较于土壤微生物多样性，植物多样性对土壤磷有效性变化的敏感性更强。因此，深入理解地上与地下生物多样性对养分供给变化的差异化响应，可为陆地生态系统功能与过程的科学管理实践提供理论依据。