Pathogen-Mediated Interactions Between Native and Introduced Grass Species

这项研究将评估专家病原体和通才病原体在本地和引进草种之间相互作用的作用。敌人释放假说认为，引进的植物种群相对于本地种群在人口统计学上的成功是天敌对本地种群更大的压制的结果。目前的数据表明，与多面手的敌人相比，引进的植物更完全地被专家释放。因此，引进种群可能会通过病原体介导的明显竞争间接抑制它们，从而获得比本地种群更大的人口统计成功，这是我的敌人假说的敌人。这项拟议的工作将使用一种实验上容易驯化的本地和引进的老田牧草系统来验证这些假设。将使用大规模调查来量化环境病原体物种丰富度和北卡罗来纳州皮埃蒙特本地和引进牧草的感染率的变化。将建立每个物种的试验性单一培养，以量化共同花园中的病原体物种丰富度和感染率。土壤肥力、真菌病原体感染和病毒病原体感染将按析因设计进行处理。总而言之，调查和实验的数据将是迄今为止对病原体在生物入侵中所起作用的最全面测试之一的前两步。据估计，生物入侵每年给美国经济造成数十亿美元的损失，并成为对本土生物多样性的主要威胁。这项工作可能会提出控制或减轻有害入侵物种的机制。此外，在这些本地和引进种群中要研究的几种病原体也是农业害虫。该项目可能会提出新的方法，从生态上控制它们在作物系统中的爆发。最后，这项研究试图阐明疾病生态学的基本原理，这些原理可能适用于动物和人类种群。

This study will evaluate the role of specialist and generalist pathogens in interactions between native and introduced grass species. The enemy release hypothesis argues that the demographic success of introduced plant populations relative to natives results from greater suppression of the natives by natural enemies. Current data suggest that introduced plants are more completely released from specialist than generalist enemies. Thus, introduced populations may achieve greater demographic success than natives by indirectly suppressing them through pathogen-mediated apparent competition, the enemy of my enemy hypothesis. The proposed work will use an experimentally tractable system of native and introduced old-field grasses to test these hypotheses. Large-scale surveys will be used to quantify variation in ambient pathogen species richness and infection rates on native and introduced grasses in the North Carolina Piedmont. Experimental monocultures of each species will be established to quantify pathogen species richness and infection rates in a common garden. Soil fertility, infection by fungal pathogens, and infection by viral pathogens will be manipulated in a factorial design. Together, the data from the survey and experiment will be the first two steps in one of the most comprehensive tests to date of the role of pathogens in biological invasions. Biological invasions are estimated to cost the US economy billions of dollars per year and be a leading threat to native biodiversity. This work may suggest mechanisms for the control or mitigation of harmful invasive species. Additionally, several of the pathogens to be studied in these native and introduced populations are also agricultural pests. This project may suggest novel approaches to the ecological control of their outbreaks in crop systems. Finally, this research seeks to shed light on fundamental principles of disease ecology that may be applied to animal and human populations.