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的变化，植物和动物的分布正在迅速变化。由于物种以不同的方式应对这些变化，生态群落的组成也在发生变化。一个重要的结果是木本灌木和乔木物种迁移或“侵入”世界各地的草原。由于木本植物物种与非木本植物具有非常不同的特征，因此它们的侵占会产生巨大的影响。例如，入侵的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，因为它们分解腐烂的植物和动物物质，并以影响植物生长的方式给土壤施肥。因此，微生物物种或其功能的变化可能反过来影响该地区的其他植物。这项研究研究了在加利福尼亚州怀特山脉上坡的一种木本物种——山艾灌木——如何影响土壤微生物群落及其相关植物物种的组成和功能。这项工作将有助于改善木本植物侵占地区的土地管理策略。它将能够培训研究生和本科生，并与博物馆和当地保护团体进行交流。该项目将建立在之前的工作基础上，该工作表明在过去 50 年里，白山山艾树的分布范围已扩大到高山草原。该项目将整合田间和温室实验、用于表征土壤群落的现代分子和酶工具以及植物人口统计模型，以：1）评估山艾树对土壤真菌群落结构和细胞外酶生产的影响，2）确定这些地下变化如何滋养回影响其他本土高山植物的表现。主要假设是，本地范围扩大的物种可能会以对现有植物群落的适应性产生关键反馈的方式影响土壤微生物群落，包括改变养分循环以及病原体与互利共生体的相对频率。这项研究将使人们更全面地了解高山灌木扩张对地上和地下的影响。研究结果将为高山植物物种在未来环境和景观变化下的长期状况以及将土壤微生物群落和植物性能联系起来的潜在机制提供有价值的信息。