As some of North America’s earliest nomads, bison likely played a major role in shaping the landscape of the continent, dispersing seeds as they roamed. But at the same time, new research shows, the herds may have influenced the microbes — such as fungi, bacteria and viruses — across the grasslands where they feasted.

A newly published study from University of Florida and Kansas State University researchers tested the saliva of bison at the Konza Prairie Biological Station (KPBS) near Manhattan, Kansas, and found at least 26 unique fungal species. It’s unclear what effect, if any, these species have on the plants and animals that share the area.

“Once we found that bison maintain plant-associated fungi in their saliva, it raised the likelihood that as they graze, they spread different microbes around,” said Karen Garrett, preeminent professor in the UF/IFAS department of plant pathology and faculty affiliate of the UF Emerging Pathogens Institute. “Historically, bison used to travel huge distances, so their effect on the prairie was probably a lot greater than it is now with the small, contained herds.”

Researchers at the KPBS gather the resident bison herd each fall for health checks, and they utilized the opportunity to swab 51 individuals for saliva. The most commonly found fungal species in the herd causes disease in sorghum and other grasses, the study noted.

The overall effects of the fungi spreading could be positive or negative for individual plants or across the entire system, Garrett said.

“As plant pathologists, we’re naturally inclined to think about plant pathogens and the fungi causing harm,” Garrett said. “We used methods to find potential plant pathogens, but the bison are probably also spreading fungi that could benefit plants, as well.”

The findings also raise questions, Garrett said. Other grazing animals may also disperse pathogens, and scientists still don’t know the cumulative effects of pathogens across multi-species plant communities.

“We don’t know much about the role of disease in wild grasslands because there are often so many species competing so densely,” she said. “If a disease were to take out a species, unless it were one of the dominant ones, it might not be noticed for a while.”

The study team, funded by a National Science Foundation grant, included collaborators Nattapol Kraisitudomsook, a former UF Ph.D. student and a UF/IFAS postdoctoral scientist at the time of the project; KSU plant pathologists Erin Frank, Shauna Dendy and John Leslie; and Amgad Saleh, then a KSU postdoctoral scientist. “Phytobiome stampede: Bison as potential dispersal agents for the tallgrass prairie microbiome” appears in the journal PhytoFrontiers: doi.org/10.1094/PHYTOFR-01-23-0004-SC.

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Featured photo courtesy of Barbara Van Slyke, Konza Prairie Biological Station, Kansas State University.

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