CONDITIONING POWER AS A DRIVER OF PLANT-SOIL FEEDBACK IN GRASSLAND RESTORATIONS

The overall objective of this proposal is to characterize the conditioning power of plants utilized for pollinator habitat restoration. I will characterize the response of the soil microbiome to varying densities of plants, and I will determine whether plants that strongly condition the soil are conducive to increased or decreased plant diversity via indirect plant-soil feedback effects. I will consider three different dimensions of conditioning power: 1) Effect size: How much a given plant species alters the soil microbiome;2) Time frame: How quickly does a given plant species alter the soil microbiome;and 3) Density-Dependence: How does effect size and time frame vary as a function of increasing plant density? To achieve this objective, I will utilize a unique habitat restoration experiment at the University of Illinois to answer the following questions:(1) How does the influence of plants on the soil microbiome vary as a function of plant density? I will describe this relationship for twelve different plant species using replicated subplots within an ongoing prairie restoration experiment.(2) What microorganisms respond to "soil conditioning" by different plant species? I will utilize high-throughput DNA sequencing to identify microbes that differentially respond to varying densities of plants.(3) Do "keystone" plants dominate the plant-soil feedback dynamics in ways that affect plant diversity? I will run a series of parallel pot-based experiments and field-based transplant experiments using plants with outsized influence over the soil microbiome, looking to see if the indirect plant-soil feedback of these plants leads to increased or decreased plant diversity.