Data from: Elevated CO2 and water addition enhance nitrogen turnover in grassland plants with implications for temporal stability

Temporal variation in soil nitrogen (N) availability affects growth of grassland communities that differ in their use and reuse of N. In a seven-year-long climate change experiment in a semiarid grassland, the temporal stability of plant biomass production varied with plant N turnover (reliance on externally acquired N relative to internally recycled N). Species with high N turnover were less stable in time compared to species with low N turnover. In contrast, N turnover at the community level was positively associated with asynchrony in biomass production, which in turn increased community temporal stability. Elevated CO2 and summer irrigation, but not warming, enhanced community N turnover and stability, possibly because treatments promoted greater abundance of species with high N turnover. Our study highlights the importance of plant N turnover for determining the temporal stability of individual species and plant communities affected by climate change.

土壤有效氮的时间动态变化，会影响因氮素利用与再利用模式不同而产生差异的草原群落的生长状况。本研究依托一项在半干旱草原开展的七年期气候变化控制实验，发现植物生物量生产的时间稳定性随植物氮周转（即相较于内部循环氮的外源氮获取依赖度）发生变化。氮周转速率较高的物种，其时间稳定性相较于氮周转速率较低的物种更差。与之相反，群落水平的氮周转速率与生物量生产的异步性呈正相关，而后者又提升了群落的时间稳定性。CO₂浓度升高与夏季灌溉（而非增温）可提升群落氮周转速率与稳定性，其潜在机制可能是该类实验处理促进了高氮周转速率物种的丰度提升。本研究凸显了植物氮周转速率在调控受气候变化影响的单一物种种群与植物群落时间稳定性过程中的重要作用。