Dr. Jane E. Stewart is an Associate Professor of Plant Pathology in the Department of Agricultural Biology at Colorado State University in Fort Collins, Colorado, USA. Her research focuses on forest, shade, and fruit trees, addressing critical issues in tree health through the lens of plant pathology. Dr. Stewart brings extensive expertise in fungal biology, population genetics and genomics, molecular diagnostics, and the management of plant pathogens particularly invasive and emerging pathogens affecting trees.

Over the course of her career, Dr. Stewart has published more than 100 scholarly manuscripts spanning various forest and tree crop pathosystems. Her research emphasizes the speciation of tree pathogens and explores host-pathogen interactions at multiple levels, from the microbiome to the molecular scale. She is also actively engaged in developing practical management strategies to combat tree diseases and enhance sustainable forestry and agriculture.

In addition to her research, Dr. Stewart teaches undergraduate and graduate courses at Colorado State University. Her undergraduate course, Tree Health and Management, covers a wide array of tree diseases and insect pests along with their management practices. She also teaches a graduate-level course on Fungal Biology and Genetics, sharing her deep knowledge and research experience with the next generation of plant pathologists.

Dr. Stewart’s research program has a global focus, aiming to improve understanding of the biology, ecology, genetics, and management of emerging tree pathogenic fungi. She currently serves as Editor-in-Chief of the internationally recognized journal Forest Pathology, reflecting her leadership and influence in the field.

Characterizing Patterns Associated with Airborne Microbial Communities in Forest and Grassland Ecosystems

Understanding how and what types of microorganisms move through the air is important for early warning detection systems for human and ecosystem health. The atmosphere harbors a diverse and dynamic reservoir of microorganisms, yet their distribution, especially for fungi, in the atmosphere and response to environmental variation remains a subject of ongoing investigation. In this study, we compared airborne bacterial and fungal communities in subalpine forest and steppe grassland sites, over diel, vertical, and seasonal gradients. Air samples were collected at three heights over four months at the subalpine forest with concurrent sampling in the steppe grassland during two of those months. We observed that fungal communities had greater site-specific variability and sensitivity to environmental factors than bacterial communities. This was most apparent in the subalpine forest, where vertical stratification and diel cycles significantly structured microbial diversity. In comparison, bacterial communities were temporally dynamic but showed weaker responses to local environmental conditions and minimal site-level differences. This may indicate broader dispersal and a ubiquitous set of bacterial taxa. Environmental drivers such as atmospheric moisture and air pressure influenced microbial beta-diversity in the subalpine forest, while air temperature and wind speed impacted diversity in the steppe grassland, again highlighting ecosystem-specific responses. Despite compositional differences, a group of shared bacterial and fungal taxa was consistently detected across sites. Most of these shared taxa were detected at greater heights in the subalpine forest. This, along with wind patterns moving eastward from the subalpine forest towards the steppe grassland, indicates potential atmospheric transport between sites, with taxa dispersal being filtered by height. These results underscore the role of ecosystem structure, meteorological conditions, and air mass movement in shaping the aerobiome. Our data suggest that airborne microbial communities are shaped by both local emission and long-range atmospheric transport processes.

Keywords: Aerobiome, ecosystems, microbial diversity, transport .