Zhang Yunhai, Loreau Michel, Lü Xiaotao, He Nianpeng, Zhang Guangming, Han Xingguo
State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
Centre for Biodiversity Theory and Modelling, Station d'Ecologie Expérimentale du CNRS, Moulis, 09200, France.
Glob Chang Biol. 2016 Apr;22(4):1445-55. doi: 10.1111/gcb.13140. Epub 2016 Feb 9.
Biodiversity generally promotes ecosystem stability. To assess whether the diversity-stability relationship observed under ambient nitrogen (N) conditions still holds under N enriched conditions, we designed a 6-year field experiment to test whether the magnitude and frequency of N enrichment affects ecosystem stability and its relationship with species diversity in a temperate grassland. Results of this experiment showed that the frequency of N addition had no effect on either the temporal stability of ecosystem and population or the relationship between diversity and stability. Nitrogen addition decreased ecosystem stability significantly through decreases in species asynchrony and population stability. Species richness was positively associated with ecosystem stability, but no significant relationship between diversity and the residuals of ecosystem stability was detected after controlling for the effects of the magnitude of N addition, suggesting collinearity between the effects of N addition and species richness on ecosystem stability, with the former prevailing over the latter. Both population stability and the residuals of population stability after controlling for the effects of the magnitude of N addition were positively associated with ecosystem stability, indicating that the stabilizing effects of component populations were still present after N enrichment. Our study supports the theory predicting that the effects of environmental factors on ecosystem functioning are stronger than those of biodiversity. Understanding such mechanisms is important and urgent to protect biodiversity in mediating ecosystem functioning and services in the face of global changes.
生物多样性通常会促进生态系统的稳定性。为了评估在环境氮（N）条件下观察到的多样性 - 稳定性关系在氮富集条件下是否仍然成立，我们设计了一项为期6年的田间试验，以测试氮富集的强度和频率是否会影响温带草原生态系统的稳定性及其与物种多样性的关系。该实验结果表明，添加氮的频率对生态系统和种群的时间稳定性以及多样性与稳定性之间的关系均无影响。添加氮通过降低物种异步性和种群稳定性显著降低了生态系统稳定性。物种丰富度与生态系统稳定性呈正相关，但在控制了添加氮强度的影响后，未检测到多样性与生态系统稳定性残差之间存在显著关系，这表明添加氮的影响与物种丰富度对生态系统稳定性的影响之间存在共线性，且前者强于后者。在控制了添加氮强度的影响后，种群稳定性和种群稳定性残差均与生态系统稳定性呈正相关，这表明在氮富集后组成种群的稳定作用仍然存在。我们的研究支持了这样一种理论预测，即环境因素对生态系统功能的影响强于生物多样性的影响。面对全球变化，了解这些机制对于保护生物多样性以调节生态系统功能和服务而言至关重要且刻不容缓。
