Amphibian microbial community assembly in a changing world: disentangling drivers of host microbiome recruitment and function

Understanding the impact of habitat disturbances on wildlife health is crucial in an era of global change. This research focuses on how disruptions in habitat connectivity affect microbial communities that live on amphibians. These microbiomes help protect amphibians from one of the most devastating pathogens of vertebrates, a skin fungus that is lethal to hundreds of species globally. By studying how frogs recruit these protective microbiomes from their environment, we aim to discover how environmental disturbance and shifts in habitat connectivity influence their ability to resist fungal infections. This work will provide new insights into the health of wildlife populations in disturbed and fragmented landscapes, helping us better predict and respond to environmental challenges and disease emergence. The researchers will work with the One Health Microbiome Center at Penn State to develop advanced ecological modeling tools and train the next generation of scientists. Additionally, they will partner with the Penn State Office of Science Outreach to organize a summer camp for middle school students, to immerse students in the fascinating world of microbes through fun, hands-on microbial ecology activities. A cornerstone of the proposed research is to examine the adaptive microbiome principle, a deterministic process where previous pathogen exposure generates host-associated microbial communities that are enriched with pathogen-inhibiting function, which in turn enhances host resistance in subsequent pathogen exposures. Recent findings, however, also support the hypothesis that individual-level habitat use and the nature of the environmental pool of microorganisms play a key role in assembly of host-associated microbial communities through stochastic processes. The balance between these two potential mechanisms is unresolved. The two focal aims of this research include: 1) experimentally testing the adaptive microbiome principle by housing amphibians in environments with distinct microbial pools and introducing varying levels of the focal fungal pathogen under controlled laboratory conditions, and 2) investigating how habitat fragmentation, environmental microbes, and pathogen exposure affect skin microbiome assembly and function in amphibians along their natural movement paths in field conditions. These aims, combined, will enhance our understanding of how wildlife fauna selectively filter protective microbiomes in the face of increasing environmental change and pathogen pressure.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.