February 28, 2025: Caves are extreme ecosystems where the scarcity of light and nutrients limits life. However, bat guano enables the development of unique animal communities that take advantage of this resource to thrive.

By analyzing sediments from karst caves in Croatia, a global biodiversity hotspot, we found that sites visited by bats, and therefore enriched with their guano, harbor more diverse and abundant communities of Arcellinida. These communities include species and genetic variants that could be endemic to the region, mirroring patterns found in animals.

These findings are available in a new study published in the journal Microbial Ecology.