Professor Timothy James has been awarded a grant from the U.S. Department of the Interior for his research investigating the role of the North American bullfrog in spreading chytridiomycosis across endangered frog populations in the Atlantic Forest of Brazil. James is part of a program through the U.S. Fish and Wildlife Service, a bureau of the DOI, called Wildlife Without Borders: Amphibians in Decline.
“The diversity of amphibians in Brazil is staggering and surpasses that of any other country,” states the project summary. “Unfortunately, many of the amphibians endemic to the Atlantic Forest of Brazil are endangered and declining due to habitat loss and other factors. These factors include the presence of exotic diseases such as chytridiomycosis caused by the fungus Batrachochytrium dendrobatidis (Bd) and exotic amphibian species such as the invasive North American bullfrog (Lithobates catesbeianus, Lc). Lc has invaded the Atlantic Forest following its introduction in the 1930s for the purposes of frog farming, and Lc on Atlantic Forest farms have been shown to be frequently infected with chytridiomycosis. Farm infections are largely the result of a hypervirulent and globally circulating genotype of Bd. Our research has recently shown that a less virulent genotype is endemic to the Atlantic Forest and may be undergoing replacement by the more virulent genotypes. We hypothesize that Lc ranaculture (frog farming) across the Atlantic Forest has created ‘incubators’ of disease in the Atlantic Forest that has spilled over to infect the native herpetofauna (amphibians and reptiles). However, an overall picture of the role of Bd in causing declines of amphibians in the region is hindered by a paucity of data.
“In this study, we will determine the prevalence of both Bd and Lc for three critically endangered species and additional non-endangered species (controls selected during field trips that are threatened both by Bd and Lc). Our methods involve surveying for Bd and Lc in both mainland regions where Lc is known to occur and comparisons to islands where Lc do not occur. We anticipate sampling for a two-year period in order to establish population trends. Using molecular techniques we will test for both endemic and pandemic genotypes of Bd. These data will inform conservation groups and government agencies on the importance of curtailing the escape of Lc individuals from frog farms in the region to reduce the spread of an emerging disease and improve the chances of saving endangered species from extinction.”
“Wildlife Without Borders: Amphibians in Decline is a fantastic program that treats species decline and extinction as a global problem and allows U.S. scientists to make an impact in countries where the amphibian crisis is most grave,” said James. “In particular, this mess we've created through the global appetite for frogs' legs has led to the establishment of frog farms throughout South America, and the subsequent escape of this invasive species into the most amphibian rich regions of the world. Brazil has over 100 threatened species of amphibians, and this project will investigate the potential impacts of bullfrog presence and fungal disease on the conservation of a few precious focal species." The 26,000 grant is for a year and a half.
Caption: A bullfrog devouring another frog in Brazil's Atlantic Forest. The North American bullfrog is an aggressive, carnivorous species originally native to eastern North America. Bullfrogs are raised for food on frog farms in Taiwan, Brazil and Ecuador and shipped worldwide. In Brazil, bullfrogs have established feral colonies in the Atlantic Forest. The native frog in this photo is from the species Hypsiboas faber. Credit: Julia Tolledo.