“Ranaviruses infect mountain yellow-legged frogs (Rana muscosa and Rana sierrae) threatened by Batrachochytrium dendrobatidis” by Tom, Roland, and Angela Picco (United States Fish and Wildlife Service) appears in Herpetological Conservation and Biology. The paper (available here) documents the presence of a ranavirus in a small number of mountain yellow-legged frog populations. Despite causing occasional tadpole mortality events, ranaviruses play a small role in large scale mountain yellow-legged frog declines, especially when compared to the fungal pathogen Batrachochytrium dendrobatidis.
Ecological consequences of frog declines
Read the new paper here. Published today in the journal Ecosphere, Tom, Roland, and Cherie Briggs (UC Santa Barbara) describe some of the ways in which mountain yellow-legged frog declines impact alpine lake communities. Contrary to expectations, the large scale loss of these frogs is not associated with secondary extinctions or changes in structure and composition of the benthic macroinvertebrate community, which contains most of the prey and competitor species for frogs and tadpoles. Notably, these results differ from 1) the consequences of frog declines in other ecosystems, and 2) the consequences of fish introductions in the Sierra. Although impacts of frog declines on the taxa examined in this study were small, mountain yellow-legged frog declines are associated with secondary declines in other species, like gartersnakes.
Frog conservation in Sequoia and Kings Canyon National Parks
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.