Explaining niche separation in tropical forests: feedbacks between root-fungal symbioses and soil phosphorus partitioning

高度多样性是几乎所有热带雨林的一个显著特征，它们提供许多重要的生态系统功能，并有助于社区对全球变化的适应能力。虽然已经提出了几种机制来解释热带森林多样性的起源和维持，但最近的理论工作表明，土壤磷的资源分配可能是热带植物多样性和共存的主要贡献者之一。然而，我们目前缺乏重要的实验证据来验证这一假说，这需要了解这些系统中菌根植物和真菌多样性与土壤P组分之间的关系，以及这些关系如何与P的利用有关。因此，在这项建议中，我们将确定田间植物和菌根真菌之间的相互作用网络，并通过操纵实验证明这是否与土壤因素有关，特别是与土壤磷库的组成和结构有关。这一目标需要一个全面和独特的植物多样性空间分析数据集，与原始热带森林中菌根真菌多样性和土壤营养库的新分析相结合，并进行新颖的操作实验。这个项目将表明，尽管总体上存在营养限制，但土壤中矿物质组分的多样性是否是植物超多样性的驱动因素。这将改变我们对土壤生物多样性在生态位分离中的作用的理解。该项目将为维护高度多样化的植物群落提供机械性的见解，并使我们对土壤生物多样性在热带树木群落内生态位分离中的作用的理解发生重大变化。它针对的是NERC在生物多样性方面的优先领域，并将帮助负责管理植物和土壤生物多样性以及热带生态系统提供的商品和服务的利益攸关方(见影响路径)。

High diversity is a striking feature of almost all tropical forests, which provide numerous important ecosystem functions, and contribute to the resilience of communities in response to global change. Although several mechanisms have been proposed to explain the origin and maintenance of tropical forest diversity, recent theoretical work suggest that resource partitioning for soil phosphorus (P) is likely to be one of the main contributors to tropical plant diversity and coexistence. However, we currently lack vital experimental evidence to test this hypothesis, which requires understanding the relationships among mycorrhizal plant and fungal diversity, and soil P fractions in these systems, and how these associations relate to P utilisation. In this proposal, we will therefore determine the network of interactions among plants and mycorrhizal fungi in the field, and show using manipulation experiments whether this is related to edaphic factors, and in particular the composition and structure of the soil P pool. This aim requires coupling a comprehensive and unique dataset of spatial analyses of plant diversity with new analyses of mycorrhizal fungal diversity and soil nutrient pools in pristine tropical forest, and novel manipulation experiments. This project will show whether, despite overall nutrient limitation, the diversity of a mineral fraction in the soil is a driver of plant hyperdiversity. This will make a step-change in our understanding of the role of soil biodiversity in niche separation. The project will provide mechanistic insight into the maintenance of hyper-diverse plant communities and make a step-change in our understanding of the role of soil biodiversity in niche separation within tropical tree communities. It targets NERC priority areas in biodiversity, and will aid stakeholders who are charged with managing plant and soil biodiversity and the goods and services provided by tropical ecosystems (see Pathways to Impact).