The landscape of interaction: scaling up from local plant-plant and plant-soil relationships

我的研究项目是研究植物群落的多样性和组成是如何通过植物之间以及植物和土壤群落之间的相互作用来构建的。我的短期（5年）目标是将局部尺度（毫米）的植物竞争和多营养植物-微生物相互作用扩大到景观尺度（米到公里）的植物和土壤微生物群落组成模式。我将利用多年空间明确的植物竞争和植物和土壤微生物群落组成的实地研究来表征植物之间和植物土壤反馈的跨营养水平景观。通过这个项目，我将测试1)竞争作为构建植物群落多样性和组成的局地尺度和景观水平格局的机制的相对重要性，2)是否充分了解根际植物-微生物联系是构建景观尺度植物和微生物群落多样性和组成的重要机制，以及3)在田间条件下，精细尺度土壤养分异质性如何影响植物-土壤相互作用。我的研究项目将资助三名研究生，一名硕士。研究植物竞争的学生，博士。研究植物与土壤关系的学生，获得硕士学位。学生专注于植物竞争、根系觅食动态和植物-土壤微生物相互作用的实验联系。这个研究项目将弥合已经得到充分研究的和基本的本地植物-植物和植物-土壤相互作用之间的差距，这些相互作用发生在毫米到厘米的尺度上，以及植物和土壤群落结构的景观水平模式。有大量证据表明，竞争的强度和重要性以及植物-土壤关系在环境梯度上存在差异，但很少有研究从景观角度考察这些模式。扩大到景观水平的模式和过程是具有挑战性的，因为需要评估多种相互作用的生态机制的相对重要性，但新的分析工具使这成为可能。该研究项目将首次在这些尺度之间建立桥梁，在植物-植物和植物-土壤相互作用的精细尺度、与生态学、保护生物学和群落组装等许多紧迫问题相关的中尺度模式与大尺度群落结构之间建立清晰的联系。在这个研究项目中，我将通过描述一个概念性地形，即“相互作用的景观”来跨尺度地工作，在这个地形中，局部尺度生态过程的强度和重要性的变化被映射到草地景观中。这个概念工具是理解植物和土壤群落更大规模模式的关键。使用空间明确的采样设计来描述单个植物之间的竞争模式，将使我能够对竞争作为构建植物群落多样性和组成的局部尺度和景观水平模式的机制的重要性进行跨尺度测试。同样，通过描述植物根系、土壤真细菌、古细菌和真菌群落之间的联系，我可以测试这些多营养关系在构建植物和土壤群落多样性和组成中的作用。最后，通过表征与精细尺度土壤养分异质性和微生物群落结构相关的根系模式，我将是第一批研究在田间条件下影响植物根系觅食模式的因素之一。

My research program investigates how plant community diversity and composition are structured by interactions among plants and between plant and soil communities. My short-term (5 year) objectives for this proposal are to scale up from local-scale (millimetre-metre) plant competition and multitrophic plant-microbial interactions to landscape-scale (metre to kilometre) patterns of plant and soil microbial community composition. I will utilize a spatially explicit multi-year field study of plant competition and plant and soil microbial community composition to characterize the among plants and the cross-trophic level landscape of plant soil feedback. Through this program, I will test 1) the relative importance of competition as a mechanism structuring both local-scale and landscape-level patterns of plant community diversity and composition, 2) whether well understood rhizosphere plant-microbe linkagesare an important mechanism structuring landscape-scale plant and microbial community diversity and composition, and 3) how fine-scale soil nutrient heterogeneity influences plant-soil interactions under field conditions. My research program will support three graduate students, a MSc. student focused on plant competition, a PhD. student focused on plant-soil linkages, and a MSc. student focused on experimentally linking plant competition, root foraging dynamics, and plant-soil microbe interactions. This research program will bridge the gaps between well studied and fundamentally local plant – plant and plant-soil interactions occurring at scales of millimeters to centimeters and landscape level patterns of plant and soil community structure. There is substantial evidence for variation in the strength and importance of competition and plant-soil relationships along environmental gradients, yet few studies have examined these patterns from a landscape perspective. Scaling up to landscape level patterns and processes is challenging because the relative importance of multiple interacting ecological mechanisms need to be assessed, but new analytical tools make this possible. This research program will be the first to bridge these scales, developing clear links between the fine-scale of plant-plant and plant-soil interactions, meso-scale patterns relevant to many pressing issues in ecology, conservation biology, and community assembly, to broad-scale community structure. In this research program, I will work across scales by characterizing a conceptual topography, the “landscape of interaction”, where variation in the strength and importance of local-scale ecological processes are mapped across a grassland landscape. This conceptual tool is key to understanding larger scale patterns in plant and soil communities. Using a spatially explicit sampling design to characterizing patterns of competition between individual plants will allow me to make cross-scale tests of the importance of competition as a mechanism structuring local-scale and landscape level patterns of plant community diversity and composition. Similarly by characterizing the linkages between plant root, soil eubacteria, archaea, and fungal communities across scales, will allow me to test the role of these multitrophic relationships in structuring plant and soil community diversity and composition. Finally, by characterizing rooting patterns in relation to fine-scale soil nutrient heterogeneity and microbial community structure, I will be among the first to investigate the factors that influence plant root foraging patterns under field conditions.