Seasonal Variation in Population Abundance and Chytrid Infection in Stream-Dwelling Frogs of the Brazilian Atlantic Forest

Author(s)

Ruggeri, Joice ^[1] ; Longo, Ana V. ^[2] ; Gaiarsa, Marilia P. ^[3] ; Alencar, Laura R. V. ^[3] ; Lambertini, Carolina ^[4] ; Leite, Domingos S. ^[5] ; Carvalho-e-Silva, Sergio P. ^[1] ; Zamudio, Kelly R. ^[2] ; Toledo, Luis Felipe ^[4] ; Martins, Marcio ^[3]

Affiliation

^[1] Univ Fed Rio de Janeiro, Inst Biol, Rio De Janeiro, RJ - Brazil

^[2] Cornell Univ, Dept Ecol & Evolutionary Biol, Ithaca, NY - USA

^[3] Univ Sao Paulo, Inst Biociencias, Dept Ecol, Sao Paulo - Brazil

^[4] Univ Estadual Campinas, Inst Biol, Dept Biol Anim, LaHNAB, Campinas, SP - Brazil

^[5] Univ Estadual Campinas, Inst Biol, Dept Genet Evolucao & Bioagentes, Lab Antigenos Bacterianos, Campinas, SP - Brazil

• Document type: Journal article
• Source: PLoS One; v. 10, n. 7 JUL 10 2015.
• Web of Science Citations: 10

Abstract

Enigmatic amphibian declines were first reported in southern and southeastern Brazil in the late 1980s and included several species of stream-dwelling anurans (families Hylodidae and Cycloramphidae). At that time, we were unaware of the amphibian-killing fungus Batrachochytrium dendrobatidis (Bd); therefore, pollution, habitat loss, fragmentation and unusual climatic events were hypothesized as primary causes of these declines. We now know that multiple lineages of Bd have infected amphibians of the Brazilian Atlantic forest for over a century, yet declines have not been associated specifically with Bd outbreaks. Because stream-dwelling anurans occupy an environmental hotspot ideal for disease transmission, we investigated temporal variation in population and infection dynamics of three stream-adapted species (Hylodes asper, H. phyllodes, and Cycloramphus boraceiensis) on the northern coast of Sao Paulo state, Brazil. We surveyed standardized transects along streams for four years, and show that fluctuations in the number of frogs correlate with specific climatic variables that also increase the likelihood of Bd infections. In addition, we found that Bd infection probability in C. boraceiensis, a nocturnal species, was significantly higher than in Hylodes spp., which are diurnal, suggesting that the nocturnal activity may either facilitate Bd zoospore transmission or increase susceptibility of hosts. Our findings indicate that, despite long-term persistence of Bd in Brazil, some hosts persist with seasonally variable infections, and thus future persistence in the face of climate change will depend on the relative effect of those changes on frog recruitment and pathogen proliferation. (AU)

• FAPESP's process: 11/51694-7 - Into the heart of an epidemic: a US-Brazil collaboration for integrative studies of the amphibian-killing fungus in Brazil
• Grantee: Luis Felipe de Toledo Ramos Pereira
• Support Opportunities: Regular Research Grants
• FAPESP's process: 08/50325-5 - Conservation of Brazilian amphibians: a special focus on the Mata Atlântica
• Grantee: Luis Felipe de Toledo Ramos Pereira
• Support Opportunities: Research Grants - Young Investigators Grants