DISSERTATION RESEARCH: Ecological and Evolutionary Implications of Rodent-mediated Spore Dispersal of Arbuscular Mycorrhizal Fungi

科学家们越来越认识到土壤传播生物的生态重要性。例如，被称为丛枝菌根真菌的共生土壤真菌是大多数植物吸收养分所必需的。丛枝菌根真菌群落的种类组成被认为对植物群落有很大的影响。因此，了解不同菌根真菌种类在土壤中的分布，以及导致这些分布的因素，将有助于全面了解森林更新的过程。虽然大多数种类的菌根真菌通过根生长短距离传播，但一小部分菌根真菌物种可以通过啮齿动物长距离传播。这些物种以相对较大的集群产生孢子，这些孢子被啮齿动物吃掉，并作为活孢子在它们的粪便中传播。我的论文研究旨在解决啮齿动物介导的孢子扩散到真菌和热带树木幼苗的生态和进化重要性。具体来说，啮齿动物的运动模式是否与啮齿动物分散的丛枝菌根真菌的分布有关？此外，植物对啮齿动物传播的菌根真菌的反应是否与对无法通过啮齿动物传播的真菌的反应不同？此外，森林破碎化对啮齿动物传播菌根真菌的影响是什么？除了提供关于土壤真菌及其传播者对热带森林再生的重要性的必要资料外，该项目还将促进若干拉丁美洲学生的生物学培训。这个项目已经让我有机会共同指导一名哥伦比亚学生的本科论文，并将让至少两名巴拿马本科生有机会学习研究地上和地下生物的技术。

The ecological importance of soil-borne organisms are becoming increasing appreciated by scientists. For example, symbiotic soil fungi called arbuscular mycorrhizal fungi are required by most plants for nutrient uptake. Species composition of arbuscular mycorrhizal fungal communities is thought to have great influence on the plant community. Therefore, understanding how different mycorrhizal fungal species are distributed in the soil, and what factors lead to these distributions, will contribute to a full understanding of the process of forest regeneration. While most species of mycorrhizal fungi are dispersed short-distances through root growth, a subset of mycorrhizal fungal species can be dispersed long distances by rodents. These species produce their spores in relatively large clusters, which are consumed by rodents and passed as living spores in their feces. My dissertation research aims to address the ecological and evolutionary importance of rodent-mediated spore dispersal to both fungi and to tropical-tree seedlings. Specifically, can rodent movement patterns be linked to the distribution of rodent-dispersed arbuscular mycorrhizal fungi? Also, do plants respond differently to rodent-dispersed mycorrhizal fungi than to fungal species incapable of rodent-mediated dispersal? Furthermore, what are the consequences of forest fragmentation on the dispersal of mycorrhizal fungi by rodents? Besides providing needed information on the importance of soil fungi and their dispersers to the regeneration of tropical forests, this project will facilitate the biological training of several Latin American students. This project has already allowed me the opportunity to co-direct the undergraduate thesis of a student from Colombia and will allow at least two Panamanian undergraduates the opportunity to learn techniques for studying both above- and belowground organisms.