My research broadly focuses on determining the biotic and abiotic drivers of soil microbial community composition and how in turn the composition of soil microbes affects ecosystem-level processes. To understand these dynamics, I study both how microbes are dispersed worldwide and how microbial community composition affects litter decomposition and soil carbon cycling.
1) Belowground drivers of aboveground nutrient cycling and productivity in growing forests
Collaborators: Christine Hawkes and Ann Russell
We are examining how microbial community composition and physiology in secondary tropical forests control carbon and nutrient cycling.
2) Aerial fungal dispersal rates, trajectories and sources in Southern California
Collaborator: Kathleen Treseder
Despite the importance of microbial community composition in litter decomposition, nutrient cycling and ultimately primary productivity, we lack fundamental knowledge of how microbes are dispersed worldwide. Conventional knowledge suggests that microbes are infinitely dispersable, but more current research has indicated that this assumption may be flawed. For my dissertation research, I seek to understand how fungi disperse aerially by characterizing rates of dispersal and seasonal fluxes in airborne fungal community composition while coupling this data to weather models to predict potential source populations.
Funding: UC Reserves Mathias Grant and Kearney Foundation
3) Patterns of fungal community composition and diversity in soils - a global synthesis
Collaborators: Krista McGuire, Christine Hawkes and Kathleen Treseder
While many studies have linked soil fungal community composition to abiotic and biotic factors, few studies have been conducted at the global scale. To truly understand how microbes will respond to changes in climate and human perturbations, we are conducting a global synthesis of published 18S and 28S sequences to link fungal community composition and phylogenetic structure to abiotic and biotic drivers. This work is critical to understand how clades of fungi are distributed globally and how these distributions may be affected by changes in climate.
Kivlin, S.N., C.V. Hawkes, and K.K. Treseder. 2011. Global diversity and distribution of arbuscular mycorrhizal fungi. Soil Biology and Biochemistry 43: 2294-2303.
Collaborator: Kathleen Treseder
4) Fungal diversity and community composition affect litter decomposition
Laboratory research has shown that the structure of fungal communities affects the rate of litter decomposition, with more diverse fungal communities accelerating decomposition. We have developed a novel approach to test these assumptions in the field setting to understand exactly what role composition and diversity each play in determining litter decay rates.
5) Does spore morphology predict dispersal capability?
Collaborators: Jim Randerson, Kathleen Treseder, Yang Chen
Fungal spores exhibit a wide range of morphologies which may influence their ability to disperse aerially to new locations. We are currently constructing a database of over 3000 species to determine if this morphology is correlated with fungal life history, biogeography, invasibility, and succession status.
6) Microbial controls over restoration in degraded Coastal Sage Scrub
Collaborators:Riley Pratt, Jessica Pratt, Margaret Royall and Jenny Talbot
California coastal sage scrub is one of the most endangered ecosystems worldwide. We seek to understand how microbial-mediated restoration methods will restore native plant communities and nutrient cycling in degraded coastal sage scrub.
7) Do established microbial communities resist colonization by novel taxa?
We currently do not understand how established fungal communities can be invaded by new colonizers. In Alaska I am manipulating litter fungal communities along a diversity gradient of 1 to 16 species and assessing how they are invaded by nearby environmental isolates.
1) The effects of plant diversity and origin on soil microbial communities
Collaborator: Christine Hawkes
2) Soil carbon cycling in response to changing precipitation regimes in California grasslands
Collaborators: Christine Hawkes, Blake Suttle, Meredith Thomsen, Valerie Huguet and Jenny Rocca
3) Soil bacterial biogeography and phylogenetic relatedness based on published 16S sequences: a meta-analysis
Collaborators: Eric Miller, Mathew Leibold and Christine Hawkes