DISSERTATION RESEARCH: The role of plant-soil interactions in woody shrub expansion in the White Mountains of California

论文研究：植物与土壤相互作用在加州怀特山木本灌木扩张中的作用

• 批准号: 1701979
• 负责人: Jeffrey Diez
• 金额: $ 1.99万
• 依托单位: University of California-Riverside
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-06-01 至 2019-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1701979&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; role; plant; soil

Plant and animal distributions are changing rapidly as a result of environmental and land use change. Because species respond to these changes in different ways, the composition of ecological communities is also changing. One important result is the movement or "encroachment" of woody species of shrubs and trees into grasslands around the world. Because woody plant species have very different characteristics than non-woody plants, their encroachment can have dramatic effects. For example, encroaching plants may affect microbial organisms living in the soil, such as bacteria and fungi. These soil organisms are very important for nutrient cycling and soil health because they break down decaying plant and animal material and fertilize the soil in ways that affect plant growth. Therefore, changes in the species of microbial organisms, or how they function, could in turn affect other plants in the area. This research studies how a woody species, a sagebrush shrub, that is moving uphill in the White Mountains of California, affects composition and function of soil microbial communities and the plant species they associate with. This work will be helpful in improving land management strategies in areas experiencing woody plant encroachment. It will enable training of graduate and undergraduate students and outreach to a museum and local conservation groups.This project will build upon previous work demonstrating that in the White Mountains, sagebrush has been expanding its range into alpine grasslands over the last 50 years. The project will integrate field and greenhouse experiments, modern molecular and enzymatic tools for characterizing soil communities, and plant demographic modeling to: 1) assess effects of sagebrush on soil fungal community structure and extracellular enzyme production, and 2) determine how these belowground changes feed back to affect the performance of other native alpine plants. The primary hypothesis is that native range-expanding species may affect soil microbial communities in ways that have critical feedbacks on the fitness of the existing plant community, including altering nutrient cycling and the relative frequency of pathogens vs. mutualists. This research will result in a more complete understanding of the above- and belowground impacts of alpine shrub expansion. Results will provide valuable information on the long-term status of alpine plant species under future environmental and landscape change, and the underlying mechanisms that link soil microbial communities and plant performance.

由于环境和土地利用变化，动植物分布正在迅速变化。由于物种以不同的方式对这些变化做出反应，因此生态群落的组成也在发生变化。一个重要的结果是灌木和树木的木本种类的运动或“侵占”进入了世界各地的草原。由于木本植物的特征与非木质植物具有截然不同的特征，因此它们的侵占可能会产生巨大的影响。例如，侵蚀植物可能会影响生活在土壤中的微生物，例如细菌和真菌。这些土壤生物对于养分循环和土壤健康非常重要，因为它们分解了腐烂的动植物物质，并以影响植物生长的方式施肥。因此，微生物的种类的变化或它们的功能可能会影响该地区的其他植物。这项研究研究了一种在加利福尼亚州白山上山的木质物种，一种鼠尾草灌木，如何影响土壤微生物群落及其与之相关的植物物种的组成和功能。这项工作将有助于改善木质植物侵占的地区的土地管理策略。它将能够对研究生和本科生进行培训，并向博物馆和当地保护小组进行宣传。该项目将基于以前的工作，证明在怀特山脉，Sagebrush在过去50年中一直将其范围扩展为高山草原。该项目将将现代分子和酶促工具集成到表征土壤群落的现代分子和酶促工具，并将植物人口统计模型整合到：1）评估鼠尾草对土壤真菌群落结构和细胞外酶产生的影响，以及2）确定这些下面的地下地面会如何反馈以影响其他天然养蜂植物的表现。主要的假设是，膨胀天然范围的物种可能会以对现有植物群落的适应性的重要反馈方式影响土壤微生物群落，包括改变营养循环以及病原体与共同主义者的相对频率。这项研究将使人们对高山灌木扩展的上述和地下影响有更全面的了解。结果将提供有关未来环境和景观变化下高山植物物种的长期状态的宝贵信息，以及将土壤微生物群落和植物性能联系起来的基本机制。