群落时间稳定性对刈割和养分富集的响应随时间的变化

Temporal change in community temporal stability in response to mowing and nutrient enrichment:evidence from a 15-year grassland experiment

土地利用和养分富集能对生物多样性和生态系统功能产生巨大的影响。然而,群落时间稳定性对土地利用和养分富集的响应是如何随时间变化的尚不清楚。作为历经15年(2005-2019)野外实验的一部分,本研究旨在探索在蒙古高原温带草原上,刈割、氮添加和磷添加对群落时间稳定性的效应。经过15年的实验,氮添加和磷添加均降低了群落时间稳定性,尤其是灌木和半灌木功能群的时间稳定性。刈割仅在实验早期(2005-2009)增加群落时间稳定性。氮添加在实验早期和末期(2015-2019)降低了群落时间稳定性,但在实验中期(2010-2014)反而提高了群落时间稳定性。磷添加在实验早期只轻微降低群落时间稳定性,但在实验末期显著降低群落时间稳定性。氮添加引起的群落时间稳定性变化的波动主要归因于其对物种异步性和种群时间稳定性的不同影响。我们的发现强调了植物功能群和物种异步性在调控群落时间稳定性方面的重要作用,以及仍然需要进行更长期的研究,以准确预测全球变化背景下的生态系统响应模式。

Land use and nutrient enrichment can substantially affect biodiversity and ecosystem functioning.However,whether and how the responses of community temporal stability to land use and nutrient enrichment change with time remain poorly understood.As part of a 15-year(2005-2019)field experiment,this study was conducted to explore the effects of mowing,nitrogen(N)and phosphorus(P)additions on community temporal stability in a temperate steppe on the Mongolian Plateau.Over the 15 years,N and P additions decreased community temporal stability by reducing the population stability,especially the shrub and semi-shrub stability.However,mowing increased community temporal stability in the early stage(2005-2009)only.Nitrogen addition suppressed community temporal stability in the early and late(2015-2019)stages,whereas enhanced it in the intermediate stage(2010-2014).Phosphorus addition decreased community temporal stability marginally in the early stage and significantly in the late stage.The fluctuations of N-induced changes in community temporal stability are mainly explained by its diverse effects on species asynchrony and population stability over time.Our findings highlight the important role of plant functional groups and species asynchrony in regulating community temporal stability,suggesting that more long-term studies are needed to accurately forecast ecosystem response patterns in the context of global change.