The newly identified fungal pathogen, Batrachochytrium, has recently been implicated as causing the decline of amphibians worldwide.
We aim to determine the origin of chytridiomycosis (the disease caused by Batrachochytrium), and understand how anthropogenic environmental changes influence its prevalence and spread. Our research will focus specifically on the relationship between Batrachochytrium and the mountain yellow-legged frog (Rana muscosa), a once-common amphibian in California's Sierra Nevada mountains. R. muscosa is an ideal study host as it is still common enough despite population declines to be used in experiments, and populations are strongly influenced by chytridiomycosis infection. As with animal populations throughout the world, amphibians in the Sierra Nevada are being subjected to an increasing array of anthropogenic stressors including exotic species introductions, habitat fragmentation, and chemical contaminants and these may change the prevalence and spread of disease. Using a team with expertise in pathogenic fungi, epidemiology, amphibian ecology, population genetics, and statistical and mechanistic modeling, our specific objectives are to: 1) describe the origin of Batrachochytrium to determine whether its association with amphibians in the Sierra Nevada represents an old association or a recent expansion of the fungus into previously uninfected frogs; 2) describe the effect of infection and spread on frog population dynamics using temporal resurveys of sites identified from an existing database of 4,500 water bodies in the Sierra Nevada; 3) develop statistical models to describe the effect of nonnative fish, habitat fragmentation, and windborne agricultural contaminants on the distribution of frogs and chytridiomycosis; and 4) develop detailed mechanistic models to predict the likely effects of various biological mechanisms (both natural and anthropogenic) on the incidence, spatial distribution, and persistence of chytridiomycosis, and to predict the impact of this disease on the abundance and dynamics of R. muscosa. Given the paucity of studies of disease in animal populations in the wild, the results of our study will provide important insights into disease dynamics in other systems, and aid in efforts to protect biodiversity in the face of emerging infectious diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of Environmental Health Sciences (NIEHS)
Type
Research Project (R01)
Project #
5R01ES012067-05
Application #
7066613
Study Section
Special Emphasis Panel (ZAI1-ALR-F (J1))
Program Officer
Heindel, Jerrold
Project Start
2002-06-01
Project End
2008-05-31
Budget Start
2006-06-01
Budget End
2008-05-31
Support Year
5
Fiscal Year
2006
Total Cost
$439,425
Indirect Cost
Name
University of California Berkeley
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
124726725
City
Berkeley
State
CA
Country
United States
Zip Code
94704
Knapp, Roland A; Fellers, Gary M; Kleeman, Patrick M et al. (2016) Large-scale recovery of an endangered amphibian despite ongoing exposure to multiple stressors. Proc Natl Acad Sci U S A 113:11889-11894
Voyles, Jamie; Vredenburg, Vance T; Tunstall, Tate S et al. (2012) Pathophysiology in mountain yellow-legged frogs (Rana muscosa) during a chytridiomycosis outbreak. PLoS One 7:e35374
Vredenburg, Vance T; Knapp, Roland A; Tunstall, Tate S et al. (2010) Dynamics of an emerging disease drive large-scale amphibian population extinctions. Proc Natl Acad Sci U S A 107:9689-94
Briggs, Cheryl J; Knapp, Roland A; Vredenburg, Vance T (2010) Enzootic and epizootic dynamics of the chytrid fungal pathogen of amphibians. Proc Natl Acad Sci U S A 107:9695-700
Andre, Sara E; Parker, John; Briggs, Cheryl J (2008) Effect of temperature on host response to Batrachochytrium dendrobatidis infection in the mountain yellow-legged frog (Rana muscosa). J Wildl Dis 44:716-20
Wake, David B; Vredenburg, Vance T (2008) Colloquium paper: are we in the midst of the sixth mass extinction? A view from the world of amphibians. Proc Natl Acad Sci U S A 105 Suppl 1:11466-73
Morgan, Jess A T; Vredenburg, Vance T; Rachowicz, Lara J et al. (2007) Population genetics of the frog-killing fungus Batrachochytrium dendrobatidis. Proc Natl Acad Sci U S A 104:13845-50
Knapp, Roland A; Boiano, Daniel M; Vredenburg, Vance T (2007) Removal of nonnative fish results in population expansion of a declining amphibian (mountain yellow-legged frog, Rana muscosa). Biol Conserv 135:11-20
Finlay, Jacques C; Vredenburg, Vance T (2007) Introduced trout sever trophic connections in watersheds: consequences for a declining amphibian. Ecology 88:2187-98
Borer, Elizabeth T; Briggs, Cheryl J; Holt, Robert D (2007) Predators, parasitoids, and pathogens: a cross-cutting examination of intraguild predation theory. Ecology 88:2681-8

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