Determining the role of plant-soil-microbial relationships in forest ecosystem function and biogeochemistry

Plant-soil-microbial relationships are an essential component of ecosystem function; however, they remain critically underexplored relative to aboveground aspects of ecosystems. In my dissertation, I seek to better understand how interactions among plants, microbial communities, and their environment drive surrounding soil microbiome composition and biogeochemical processes in forests. This work integrates important global change factors like invasive species and increased anthropogenic nutrient deposition while taking a global perspective, spanning temperate and tropical ecosystems. In my first and second chapters, I show how the invasive species Alliaria petiolata (garlic mustard) has a dynamic relationship with soil microbial communities and nitrogen cycling processes over space and time. In my third chapter, I provide evidence for the important role fungal communities play in acquiring nitrogen from soil organic matter in a montane rainforest of Panama, and how this function is diminished under elevated nitrogen deposition. Finally, a focal component of my research is how the diversity of mycorrhizal relationships between plants and fungi influences their impact on ecosystems. I explore this in-depth in my last chapter, presenting a study investigating how ectomycorrhizal tree species and fungal communities differ in their associated effects on important ecosystem traits like soil organic matter dynamics and extracellular enzyme activities. Overall, my dissertation supports the inclusion of microbial communities as critical independent players in ecological phenomena, promoting the use of microbially-explicit paradigms and models in informing conservation decision-making and predicting ecosystem response to global change. My dissertation shows that the nature of plant-soil-microbial relationships is highly context-dependent, varying based on environmental conditions, temporal factors, and species diversity.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Ecol, Evol, Conservation Biol

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2022

Author dc:creator

• Edwards, Joseph Douglas

Contributors dc:contributor

• Yang, Wendy H
• Yannarell, Anthony C
• Dalling, James
• Davis, Adam

• Microbial ecology
• biogeochemistry
• plant-microbial interactions
• forests
• ecosystem ecology
• invasive species
• DNA sequencing
• stable isotopes
• soil organic matter
• nitrogen deposition
• mycorrhizal fungi

Statement dc:rights

• Copyright 2022 Joseph Edwards

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/115459

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F115459