Synergistic effects of nitrogen and CO2 enrichment on alpine grassland biomass and community structure

Global environmental change is altering Earth’s ecosystems. However, much research has focused on ecosystem-level responses, and we know substantially less about community-level responses to global change stressors.

Here we conducted a 6-year field experiment in a high-altitude (4600 m above sea level) alpine grassland on the Tibetan Plateau to explore the effects of nitrogen (N) addition and rising atmospheric CO2 concentration on plant communities.

Our results showed that N and CO2 enrichment had synergistic effects on alpine grassland communities. Adding nitrogen or CO2 alone did not alter total community biomass, species diversity, or community composition, whereas adding both resources together increased community biomass, reduced species diversity, and altered community composition. The observed decline in species diversity under simultaneous N and CO2 enrichment was associated with greater community biomass and lower soil water content, and driven by the loss of species cha...

全球环境变化正在改变地球生态系统。然而，当前多数研究聚焦于生态系统水平的响应，而我们对群落水平响应全球变化胁迫因子的认知仍相对匮乏。

本研究于青藏高原海拔4600米的高寒草原开展了一项为期6年的野外实验，以探究氮（nitrogen）添加与大气CO₂浓度升高对植物群落的影响。

研究结果表明，氮与CO₂富集对高寒草原群落具有协同效应。单独施加氮或CO₂并不会改变群落总生物量、物种多样性或群落组成；而同时添加两种资源则会提升群落生物量、降低物种多样性并改变群落组成。同时施加氮与CO₂富集条件下观测到的物种多样性下降，与群落生物量升高及土壤含水量降低相关，且由物种[原文截断]的丧失所驱动。