UC Irvine

Fungi play critical roles in ecosystem function. Fungal pathogens, decomposers, and symbionts mediate ecosystem functions. These functions include biological control via disease, carbon emissions via decomposition rates, and carbon sequestration via plant growth rates.

Indeed, ecosystem function is partially a reflection of which fungal groups are able to disperse to and colonize in the ecosystem. Dispersal is a mechanism for fungi to follow their ideal niches as they shift under climate change. Therefore, studying fungal dispersal will allow us to understand how ecosystem function may change in concert with climate.

The goal of my dissertation is to understand airborne fungal dispersal in relation to ecosystem function. In my first chapter, I underline the importance of international cooperation when researching fungal pathogen dispersal and conducting public health surveillance on fungal diseases. I recommend actions that local, state, and national governments can take in order to improve their ability to forecast fungal dispersal and disease in humans.

My second chapter addresses differences between fungal communities in the soil versus the air across the Southwestern U.S. In order to understand dispersal differences between fungal functional groups, I sampled soil and air across Arizona, California, New Mexico, Nevada, and Utah. Then, I compared relative abundances of functional groups in soil and air, as well as their extent of occurrence (i.e., range). I discovered that fungal pathogens tend to be found at high relative abundances in the air compared to other functional groups. Fungal pathogens also have the largest extent of occurrence in the soil.

Finally, my third chapter examines changes in fungal dispersal during normal, onshore wind conditions and Santa Ana events in Southern California. I used a high-volume sampler to capture the fraction of fungi that are small enough to be inhaled deep into human lungs. I found that Santa Ana winds bring a five-fold increase of decomposer fungi that may be pre-adapted to desert conditions. Climate change will cause Southern California to become warmer and drier, which means these fungi may alter decomposition rates and carbon cycling in the future. All together, my dissertation addresses spatial and temporal changes in fungal dispersal as it relates to ecosystem function.