One paper (Jani et al. 2021) describes how infection of mountain yellow-legged frogs by the amphibian chytrid fungus causes long-term changes to the community of bacteria inhabiting the frogs’ skin (“microbiome”). Given the myriad roles played by the microbiome, including those related to immunity, changes to its structure could have additional impacts on frogs. The second paper (Joseph and Knapp 2021) shows how using the results of visual encounter surveys in analysis of mark-recapture data can improve estimates of population size. Links to the full text of both papers is available on the Publications page.
We recently sent out our annual Mountain Lakes Research Group newsletter in which we summarize the highlights from our our research and conservation-related activities in 2018. We also discuss the funding challenges that we face, exacerbated by the prolonged shutdown of the federal government, and our fundraising plans for the future. If you would like to receive future newsletters, please let us know.
The latest release in the Yosemite Nature Notes video series features the Sierra Nevada yellow-legged frog and describes ongoing efforts to recover this species in Yosemite National Park. Check it out.
A paper entitled “Disease and climate effects on individuals drive post-reintroduction population dynamics of an endangered amphibian” by Max and Roland was published in Ecosphere today. The accompanying UCSB story is available here. Although developed for mountain yellow-legged frogs, the hierarchical Bayesian hidden Markov model they developed might be applicable to other species impacted by the amphibian chytrid fungus.
In this new video, UCSB videographer Spencer Bruttig talks to Roland during a visit to one of his Yosemite study sites and gets the latest on the outcome of frog conservation efforts there. Amazingly, despite all of the challenges the Sierra Nevada yellow-legged frog has faced during the past century, the frogs are making a remarkable comeback. Hear about this exciting turn of events from someone who witnessed the frogs’ decline and now the beginning of their recovery.
In the Sierra Nevada, the winter of 2015-2016 was one of the driest on record. During the following summer, a habitat in Yosemite National Park containing Sierra Nevada yellow-legged frogs slowly dried up. Just before the last pools dried, Yosemite mounted a rescue of the tadpoles stranded in the shrinking pools. Several thousand tadpoles were collected and flown via helicopter to a lake upstream in the watershed. This video shows the rescue in action.
A paper by Roland and colleagues was published today in the Proceedings of the National Academy of Sciences, USA. The accompanying UCSB story is available here. The study shows that despite the ongoing presence of introduced fish and the amphibian chytrid fungus, Sierra Nevada yellow-legged frogs are recovering across Yosemite National Park. This recovery is occurring because some lakes have been restored to their original fishless condition, and frogs are developing increased resistance to fungal infection. These results suggest that some amphibians may be more resilient than is often assumed, and with appropriate management, declines of such species may be reversible. That is great news!
Mountain yellow-legged frog populations in Sequoia and Kings Canyon National Parks are in steep decline due to the introduction of non-native trout and the ongoing spread of the amphibian chytrid fungus. As described in this new video, to prevent frog populations from being wiped out when the fungus arrives in a population, early life stage animals (e.g., tadpoles) are being collected from those sites, raised to adulthood in captivity, and reintroduced when they are less susceptible to fungal infection. This collaboration between the National Park Service, San Francisco and Oakland Zoos, and the Mountain Lakes Research Group may portend a brighter future for this imperiled amphibian.