Doctoral Dissertations

Orcid ID

Date of Award


Degree Type


Degree Name

Doctor of Philosophy


Ecology and Evolutionary Biology

Major Professor

Jennifer A. Schweitzer

Committee Members

Joseph K. Bailey, Paul R. Armsworth, Sarah L. Lebeis


Soils contain the highest biodiversity on Earth. While the importance of the soil microbiome for larger-scale ecological phenomena such as nutrient and carbon cycling, plant growth and plant community dynamics is well-established, the fundamental question of the ecological and evolutionary function of this immense belowground microbial diversity for plant and ecosystem function still remains a great challenge in microbial ecology research. The objective of this dissertation is to understand how the importance of soil microbial community composition for plant and ecosystem function and how changes to soil microbial community composition from climate change-induced disturbance events, specifically fire, influence plant and ecosystem function. Specifically, I examine: (1) the relative importance of microbial taxa and functional genes within complex natural soil microbiomes for plant phenotypic variation in a common herbaceous plant (Solidago); (2) the trends in responses of plant-soil microbial interactions to multiple gradients of environmental stress and disturbance; (3) the effect of fire-induced changes to soil microbial community composition on the restoration success of a common tree species (Quercus velutina); and (4) the effect of fire-induced changes to composition of microbial carbon use efficiency on carbon cycling. The findings of this dissertation suggest that a small proportion of a complex soil microbial community may be important for plant variation in plant traits, and that the importance of soil microbial community composition varies among plant trait and plant species; that there is high variability in how plant-soil interactions respond to climate change-induced stressors and disturbances; and that shifts in microbial community membership can influence plant function and specific ecosystem-level processes. These ideas have broad implications for predicting and managing plant communities and ecosystems under changing environmental conditions because they show that changes in soil microbial community composition can yield significant shifts in plant and ecosystem function.

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