Data for Negative effects of phosphorus addition override positive effects of arbuscular mycorrhizal fungi on grassland temporal stability

The temporal stability of a plant community in a native grassland ecosystem is affected substantially by soil nitrogen (N) and phosphorus (P) enrichment. However, the interactions between N and P inputs and arbuscular mycorrhizal fungi (AMF) and their effects on the temporal stability of plant productivity have not yet been clarified. In this study, we combined a three-year <em>in situ</em> field experiment with a worldwide meta-analysis to assess the effects of soil fertilisation and AMF on the temporal stability of plant productivity. The addition of P decreased the stability of plant productivity as the standard deviation of plant productivity was increased directly and the temporal stability of C₃ grasses was decreased. However, there was no relationship between species richness and the stability, and of plant productivity, rather the stability of the dominant functional group and asynchrony among functional groups were the main drivers changing the stability of change in plant productivity. In both the site-specific experimental data analysis and worldwide meta-analysis, the negative effects of P addition overrode the positive effects of AMF on the temporal stability of plant communities. Overall, our study highlights the importance of soil nutrient availability over AMF in terms of shaping the temporal stability of a plant community. Our results also suggest that anthropogenic soil nutrient enrichment might reduce the temporal stability of plant communities in grassland environments regardless of the existence of AMF.天然草原生态系统中植物群落的时间稳定性，在很大程度上受土壤氮（N）、磷（P）富集的影响。然而，氮磷输入与丛枝菌根真菌（arbuscular mycorrhizal fungi, AMF）之间的交互作用，及其对植物生产力时间稳定性的影响，迄今尚未阐明。本研究结合为期三年的原位（in situ）田间试验与全球尺度元分析，评估土壤施肥与丛枝菌根真菌对植物生产力时间稳定性的调控效应。磷素添加直接提升了植物生产力的标准差，进而降低了植物生产力的稳定性，同时也降低了C3草本植物的时间稳定性。然而，物种丰富度与植物生产力稳定性之间并无关联；相较于物种丰富度，优势功能群的稳定性以及功能群间的异步性，才是驱动植物生产力稳定性变化的核心因素。无论是针对本试验位点的数据分析，还是全球尺度元分析结果均显示，磷素添加的负向效应抵消了丛枝菌根真菌对植物群落时间稳定性的正向作用。总体而言，本研究凸显了土壤养分有效性相较于丛枝菌根真菌，在塑造植物群落时间稳定性过程中的关键作用。本研究结果同时表明，无论丛枝菌根真菌是否存在，人为土壤养分富集均可能降低草原生态系统中植物群落的时间稳定性。