The Community Assembly, Composition, and Temporal Turnover of Plant-Symbiotic Fungi in Lowland Tropical Forests

• Main Author: Sanchez-Julia, Mareli
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01-01-2023
• Subjects: Ecology; Forestry; Microbiology; Physiology; Plant sciences
• ISBN: 9798381716399

Despite a century of theoretical and technological developments, community ecologists are still challenged by a unifying question: what predicts the assembly and composition of a community in spaceand time? Plant-symbiotic fungi are a compelling group to ask this question because they are subject to an additional barrier to establishment: their host plant. These fungi are incredibly diverse, varying in their biology, life-history strategies, and in the nature and degree of their symbiotic exchange. Yet, much remains unknown about their community assembly, and lowland tropical forests remain understudied despite such remarkable biodiversity. In this dissertation, I aim to uncover the community assembly, composition and temporal turnover of two groups of plant-symbiotic fungi: the foliar endophytic fungi, and the arbuscular mycorrhizal fungi. Using greenhouse experiments, field sampling, DNA sequencing and multivariate statistics, I demonstrate that hosts and their traits impact the mycobiont communities that colonize plant tissues across a range of phylogenetically distinct hosts. I suggest that these fungal communities assemble non-randomly and play important roles for plant function, especially plant nutrition. I show that substitution patterns primarily underlie temporal turnover of endophytes, where communities remain stable via replacement of endophytes over time. This dissertation advances our understanding of the community assembly of these unique fungal groups in tropical forests, and shines a small, but bright light on the entangled lives of plants and fungi.