This study found that using bat guano as fertilizer can shift soil fungal communities in harmful ways, introducing fungi linked to plant disease, food spoilage, and even human infection. Soils treated with guano contained genera like Fusarium, Curvularia, Rhizopus, and Cladophialophora, while untreated soils did not show these pathogens. I also included this research because if you forage in high-guano areas, please keep this in mind when enjoying your edible foraging finds. As an Austinite, I’m neighbors to the world’s largest urban bat colony — the Mexican free-tailed bats who roost under the Congress Avenue Bridge.