Historical amphibian declines and extinctions in Brazil linked to chytridiomycosis.
The recent increase in emerging fungal diseases is causing unprecedented threats to biodiversity. The origin of spread of the frog-killing fungusBatrachochytrium dendrobatidis(Bd) is a matter of continued debate. To date, the historical amphibian declines in Brazil could not be attributed to chytridiomycosis; the high diversity of hosts coupled with the presence of severalBdlineages predating the reported declines raised the hypothesis that a hypervirulentBdgenotype spread from Brazil to other continents causing the recent global amphibian crisis. We tested for a spatio-temporal overlap betweenBdand areas of historical amphibian population declines and extinctions in Brazil. A spatio-temporal convergence betweenBdand declines would support the hypothesis that Brazilian amphibians were not adapted toBdprior to the reported declines, thus weakening the hypothesis that Brazil was the global origin ofBdemergence. Alternatively, a lack of spatio-temporal association betweenBdand frog declines would indicate an evolution of host resistance in Brazilian frogs predatingBd's global emergence,further supporting Brazil as the potential origin of theBdpanzootic. Here, weBd-screened over 30 000 museum-preserved tadpoles collected in Brazil between 1930 and 2015 and overlaid spatio-temporalBddata with areas of historical amphibian declines. We detected an increase in the proportion ofBd-infected tadpoles during the peak of amphibian declines (1979-1987). We also found that clusters ofBd-positive samples spatio-temporally overlapped with most records of amphibian declines in Brazil's Atlantic Forest. Our findings indicate that Brazil is post epizootic for chytridiomycosis and provide another piece to the puzzle to explain the origin ofBdglobally.
Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo 13083-862, Brazil.
Tamilie
T
Carvalho
Departamento de Zoologia, Universidade Estadual Paulista, Rio Claro, São Paulo 13506-900, Brazil.
C Guilherme
CG
Becker
Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo 13083-862, Brazil toledolf2@yahoo.com.
Luís Felipe
0000-0002-4929-9598
LF
Toledo
D000663:Amphibians / Q000382:microbiology*; D000818:Animals; D044822:Biodiversity; D001938:Brazil; D008411:Chytridiomycota / Q000472:pathogenicity*; D009181:Mycoses / Q000662:veterinary*
Batrachochytrium dendrobatidis; disease distribution; host–pathogen dynamics; spatial epidemiology; spatio-temporal analysis