氮沉降对内蒙古草原植物化学计量内稳性、群落结构和生产力的影响及其机理

项目名称： 氮沉降对内蒙古草原植物化学计量内稳性、群落结构和生产力的影响及其机理

项目编号： No.31270476

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 生物科学

项目作者： 庾强

作者单位： 中国科学院沈阳应用生态研究所

项目金额： 79万元

中文摘要： 氮沉降会造成群落结构和生产力的变化以及生物多样性下降，然而其机理尚不清楚。内蒙古草原的研究表明，化学计量内稳性高的植物具有较高的优势度和稳定性，内稳性高的生态系统生产力和稳定性也较高，这说明化学计量内稳性是草原生态系统结构、功能和稳定性维持的重要机制。长期氮沉降是否会改变植物的化学计量内稳性，并通过化学计量内稳性的变化影响草原生态系统的结构和功能呢？该问题至今仍然是个谜。本项目将利用内蒙古草原生态系统国家野外观测研究站长期氮添加实验平台，分析氮添加对群落物种组成、生物多样性和生产力的影响，以及对化学计量内稳性的影响，并通过沙培实验培养长期氮添加实验中植物的种子，研究化学计量内稳性的变化是否可以遗传。最后，通过这些变化，从化学计量内稳性角度，分析氮沉降造成群落结构、生物多样性和生产力改变的机理。

中文关键词： 氮添加；群落结构；生态系统功能；全球变化；

英文摘要： Previous studies showed that nitrogen deposition significantly affected community structure, biodiversity and productivity. However, the mechanism is still not clear. Recent studies in Inner Mongolia grassland suggest dominant plant species have greater stoichiometric homeostasis - that is, the ability to maintain their elemental composition of nitrogen and phosphorus despite variation in the elemental composition of available resources - than those that are uncommon in the community. Furthermore, ecosystems dominated by homeostatic plant species have been shown to be more productive and stable. However, it is unclear the extent to which plant species within a community may vary in their stoichiometric homeostasis, whether nitrogen deposition may alter stoichiometric homeostasis of plant species, and what consequences these alterations may have for community structure and function over time. Here, we address these gaps in our understanding by first assessing variation in stoichiometric homeostasis of 12 plant species in the long term nitrogen addition experiment in Inner Mongolia grassland. We then utilize a sand culture experiment to test whether the variation of stoichimetric homeostasis will be inherited by planting the seeds from the Nitrogen addition experiment. Finally, we explore the implications of alter

英文关键词： nitrogen addition；community structure；ecosystem function；global change；