基于性状的黄土高原草地生物多样性与生态系统功能
文献类型：学位论文
| 作者 | 朱火星 |
| 学位类别 | 博士 |
| 答辩日期 | 2015-05 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 傅伯杰 |
| 关键词 | 群落构建，生物多样性-生态系统功能，植物功能性状，响应-影响 框架，生境过滤。生态位分化，生物量比假设，多样性假设, community assembly, biodiversity-ecosystem functioning, trait-based approach, habitat filtering, niche differentiation, response-effect framework |
| 其他题名 | Trait-based plant community assembly processes and biodiversity-ecosystem functioning relationship of semi- arid grasslands in Loess Plateau of China |
| 学位专业 | 生态学 |
| 中文摘要 | 植物群落构建过程和物种共存机制一直是群落生态学研究的核心问题。群落的构建过程直接影响到群落组成和结构。植物多样性作为群落结构的一个重要方面，对生态系统功能的发挥至关重要。黄土高原草地面积广大，发挥着固碳减蚀等重要生态系统功能，对于当地乃至区域环境和经济社会发展起着至关重要的作用。同时，黄土高原人类活动强烈、地区生态脆弱，因此，理解和预测未来环境变化如何影响该地区的植被组成和生态系统功能，有很强的理论意义和应用价值。 本研究以黄土高原中部羊圈沟流域半干旱草地生态系统为研究对象，采用基于植物功能性状的研究方法，尝试理解这些草地群落是如何由一个个物种构建起来的；这些群落的功能结构如何对土壤资源变化做出响应；又如何影响土壤侵蚀、碳固定等该地区主要的生态系统功能。 本研究发现： (1)多重群落构建过程共同作用，塑造了黄土高原草地群落格局。生境过滤使得群落平均功能性状范围变窄；生态位分化过程使得群落内物种在功能空间上均匀分布。相对于谱系方法，基于性状的方法能够更加有效地检验这些群落构建过程。 (2)传统的物种丰富度和根系生物量没有直接关系，但是较高的物种丰富度可能促进土壤氮含量的提升，从而间接促进根系生物量。 (3)相对于传统的物种多样性，基于性状的群落功能多样性对于土壤侵蚀有显著影响。功能分异度较高的群落能够更加有效地减缓土壤侵蚀。生态系统恢复和管理可以尝试把基于性状的方法纳入到当前的实践中，来改善生态系统功能和服务。 (4)黄土高原草地群落的功能组成（群落平均高度和比叶面积）和功能多样性（基于多个性状的功能离散度）对土壤资源变化有显著响应，同时显著影响生态系统碳储量。土壤资源的富集使得黄土高原草地群落群落平均高度和平均比叶面积增加，而功能多样性降低；功能多样性的降低进一步使得地上生物量减少，同时增加表层土壤碳储量。因此，人类活动或者气候变化导致的未来环境变化，可能对黄土高原草地群落功能结构和重要生态系统功能（土壤保持、碳固定等）产生显著影响。 这些结果表明，采用基于植物功能性状的方法能够很好地把环境变化、群落构建和生态系统功能联系起来，对于理解群落构建过程、物种共存机制、生物多样性-生态系统功能关系等有重要的理论意义。另一方面，对于如何通过改变环境状况、调节植物群落的功能组成，来控制重要的生态系统过程具有很强的指导作用。比如，可以通过提高草地群落功能多样性来减缓土壤侵蚀；通过降低土壤养分状况促进群落功能多样性的增加。 |
| 英文摘要 | The inquiry for Plant community assembly processes and coexistence mechanisms is at the core of coomunity ecology, not only because of its scientific interests per se but also due to its profound effcts on community composition, structure and functions. As an important component of community strucutre, biodiversity have been shown to be a major driver of many ecosystem processes, as demonstrated by numerous biodiversity-ecosystem fucntioning studies. Semi-arid grasslands on the Loess Plateau, estimated to be 250,000 square kilometres area and cover more than 40% of the Loess Plateau, are largely limited by water and nutrient availability, which were frequently modified by intensive human activities in this region. Therefore, understanding and predicting how environmental change would alter plant community composition and ecosystem functioning are of critical importance both in theory and in practice. Using trait-based approach, this study focus on (1) how the semi-arid grasslands on the Loess Plateau of China are assembled, (2) how these assembled coomunities respond to changing soil resource availability, and (3) how the functional composition of these assembled communities affect critical ecosystem processes such as soil erosion, carbon sequenstration. The major findings of this dissertation are as follows: (1) Habitat filtering and niche differentiation operate concurrently to deterine community assembly processes of semi-arid grasslands in Loess Plateau of China. Trait-based approach is more effective in detecting these processes than phylogenetic-approach. (2) Significant indirect effects of plant species richness on root biomass were found, although no direct correlation was detected between them. In the indirect pathways, plant species richness showed a positive effect on soil total nitrogen, but a significant negative influence on soil total carbon. Soil total nitrogen and plant diversity had the largest and smallest total effect respectively on root biomass in the model. (3) A robust and strong negative effect of functional divergence (FDiv) on soil erosion was found. The prevalence of particular trait combinations can also decrease soil erosion. The greatest control over soil erosion was exerted when the community mean root diameter was small and the root tensile strength was great. (4) Community functional composition and diversity showed clear responses to changing soil resource availability, and had significant cascading effects on ecosystem C storage. Community weighted mean plant height and specific leaf area significantly increased with increasing soil resources while community functional dispersion decreased. Community functional dispersion showed a significant positive effect on aboveground biomass and a negative effect on surface soil C storage. This study showed that environmental cahgne, community assembly and ecosystem functioning can be well linked through trait-based approach. In theory, this intergation may be essential for an advanced understanding of coexistence theory, biodiversity-ecosystem function relationship. In practice, These findings may imply that the desirable ecosystem functioning can be achieved by regulating environmental conditions, such as soil resources, and community functional composition, thus improving our ability to manage the ecological consequences of potential environmental change in a rapidly changing world. |
| 源URL | [http://ir.rcees.ac.cn/handle/311016/34486]  |
| 专题 | 生态环境研究中心_城市与区域生态国家重点实验室 |
| 推荐引用方式 GB/T 7714 | 朱火星. 基于性状的黄土高原草地生物多样性与生态系统功能[D]. 北京. 中国科学院研究生院. 2015. |
入库方式： OAI收割
来源：生态环境研究中心
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