Combatting a deadly disease and conserving a landscape one frog at a time
New research supported by the U.S. National Science Foundation shows that efforts to save and reintroduce mountain yellow-legged frogs across Yosemite National Park are helping to sustain the population in the face of a deadly fungus and have the potential to inform other conservation efforts.
The amphibian chytrid fungus, Batrachochytrium dendrobatidis, which causes a disease known as chytridiomycosis, has devastated frog populations worldwide. In Yosemite, the Sierra Nevada yellow-legged frog lives in only 10% of its historic range due to population losses from the disease and other factors. Working to determine methods of saving the remaining frogs and combat the disease, researchers led by UC Santa Barbara (UCSB) biologist Roland Knapp previously demonstrated that frogs from populations that recovered naturally from B. dendrobatidis-caused declines appear to have evolved increased B. dendrobatidis resistance. In the current study, Knapp and his colleagues collected frogs from these resistant populations and reintroduced them into areas where the disease had previously wiped out frogs.
Over 17 years, Knapp, a member of the NSF Resilience Institute Bridging Biological Training and Research, an NSF Biology Integration Institute, and the team conducted 24 reintroductions across 12 sites in Yosemite. Monitoring the populations over that time, they found that the frogs could establish themselves in the previously devastated areas, even in the face of ongoing B. dendrobatidis infection, and that how well these new populations establish themselves is influenced by site, cohort and frog attributes. These results highlight the potential for disease resistance and reintroduction of resistant genotypes to enhance conservation efforts in amphibians and, more broadly, other species threatened by novel pathogens.
"This study is a nice example of how complex and multi-dimensional problems like combatting diseases require a multidisciplinary and integrated approach," said Jodie Jawor, a program director in the NSF Directorate for Biological Sciences. "The research shows factors at the individual, population and ecosystem level impact efforts to conserve species, maintain Earth's biodiversity and support vital ecosystems."