Date of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)




Katie Becklin


climate change;drought;microbial communities;plant-microbe interactions;resistance;tolerance


The ability of natural plant populations to respond in the face of rapid environmental change depends on the complex microbial communities with which they associate. The interactions plants have with their microbial symbionts impacts the plants growth, function, and subsequent reproduction. It is important to understand how climate change alters these interactions. First, I aimed to understand how the microbial communities among and within the roots of alpine plants changed in response to drought along an elevational gradient, providing insight into what environmental and ecological factors play a role in microbial community resistance to drought stress. Secondly, within plant populations this is important to understand because it is not clear how changing climatic conditions may influence the survival and functioning of plants of the same species from different host populations. And finally, I assessed how drought affected plants with specialized microbial mutualists. My dissertation uses a combination of fieldwork, a greenhouse study, molecular and biochemical analyses, and meta-analytical methods to identify the microbial community members in association with the plants of interest, elucidate the strength and direction of intraspecific microbially-mediated local adaptation, and identify stoichiometric responses of tripartite associations to drought. The first chapter characterizes how diverse microbial communities change in response to abiotic stress along an elevational gradient. The second chapter investigated the strength and direction of microbe-mediated local adaptation effects when faced with drought. The third chapter proposes to understand the investment and stoichiometric patterns of a plant associating with individual mutualistic microbes, or dual mutualists under drought. The impacts of climate variation, i.e. drought, on the dynamics of plant-microbe interactions at multiple scales because these interactions drive the structure and function of plants in ecosystems worldwide.


Open Access

Available for download on Friday, January 17, 2025