Dimensions US-China: Collaborative Research: Microbe eco-evolutionary feedbacks as drivers of plant coexistence and diversity gradients

草原占全球陆地面积的26%，占农业生产用地的80%。除了其农业重要性，草原还在各种生态系统服务中发挥关键作用，包括生产清洁水和防止洪水。天然草地往往物种丰富，丰富度随着年降雨量的增加而增加，随着干扰的增加而下降。这些多样性模式可能会产生重要的后果，因为物种丰富的草原已被证明更具生产力，对干旱、洪水或龙卷风破坏等不可预测的事件更具弹性。为了更好地管理草原地区，必须了解支配植物多样性格局和植物多样性效益的过程。创造和维持草原共存植物物种丰富多样性的不同过程尚不清楚，但最近的研究表明，植物病原体可能起到了作用。该项目通过在美国和中国境内的多个田间地点进行平行实验，考察了植物病害决定草原植物多样性自然格局的程度。本科生、研究生和博士后研究人员将接受不同领域和实验室方法的培训，包括来自伊利诺伊州、密苏里州和堪萨斯州学习地点附近的大学和社区学院的学生和教职员工。该项目的数据将为牧场的管理提供新的方向，并有助于提高农业和本土生态系统的产量和弹性。据预测，病原体在植物系统发育多样性低、植物遗传多样性低和降雨量多的草原上积累和限制植物生产力的作用最强。这些预测将通过对北美和亚洲草原的平行多样性和降雨量梯度进行的一套协调的实地观测、田间操纵和温室分析来检验。具体地说，将在美国中部和中国的降雨梯度上测试植物和病原体系统发育多样性的模式，遗传多样性导致的植物抗性模式，以及生态和进化反馈模式。实验植物群落的降雨操作将测试植物物种共存的环境依赖性，植物多样性的生产力效益，以及病原体作为这些过程的驱动因素的作用。这些经验研究将与数学模型相结合，以预测植物生物多样性的模式和效益，以及草原对环境扰动的脆弱性预测。

Grasslands comprise 26% of global land area and 80% of agriculturally productive land. In addition to their agricultural importance, grasslands also play key roles in diverse ecosystem services, including the production of clean water and the prevention of flooding. Native grasslands are often very species-rich, with richness increasing with increasing annual precipitation and declining following disturbance. These patterns of diversity can have important consequences because species-rich grasslands have been shown to be more productive and more resilient to unpredictable events like drought, flooding, or tornado damage. It is essential to understand the processes that govern both the patterns of plant diversity and the benefits of plant diversity to better manage grassland areas. The different processes that create and maintain the rich diversity of plant species coexisting in grasslands are unknown, but recent research suggests that plant pathogens may play a role. This project examines the extent plant disease determines natural patterns of plant diversity within grasslands by conducting parallel experiments at multiple field sites within the United States and China. Undergraduates, graduate students and post-doctoral researchers will be trained in diverse field and laboratory methods, including students and faculty from colleges and community colleges adjacent to study sites in Illinois, Missouri and Kansas. Data from this project will generate new directions for the management of rangelands and also lead to improvements in the yield and resilience of agricultural and native ecosystems.Pathogens are predicted to accumulate and limit plant productivity most strongly in grasslands with low plant phylogenetic diversity, low plant genetic diversity and high precipitation. These predictions will be tested through a coordinated set of field observations, field manipulations, and greenhouse assays, performed on parallel diversity and rainfall gradients in North American and Asian grasslands. Specifically, patterns of plant and pathogen phylogenetic diversity, patterns of plant resistance due to genetic diversity, and patterns of ecological and evolutionary feedback will be tested across rainfall gradients in central United States and China. Rainfall manipulations of experimental plant communities will test environmental dependence of plant species coexistence, productivity benefits of plant diversity, and the role of pathogens as drivers of these processes. These empirical studies will be integrated with mathematical models to generate predictions of patterns and benefits of plant biodiversity, as well as predictions of vulnerabilities of grasslands to environmental perturbations.