The amphibian fungus Batrachochytrium dendrobatidis (Bd) is likely responsible for the extinction of at least 100 amphibian species. In Costa Rica 50% of amphibian species began to disappear in 1986. There is a major pattern of decline due to environmental degradation and the fungal disease chytridiomycosis, however, current increased populations are observed in some endangered species.
If the fungus is present both before and after the 1986 decline, we cannot assume that Bd was soley responsible. Some amphibians may have developed resistance, or something else occurred to affect the fungus’ virulence. The former explanation promotes the need for more investigations on the possibilities of why amphibians have reestablished their populations.
Real time PCR examinations of DNA from museum specimens and wild animals were performed on anurans that had been collected during amphibian surveys from 1964-2011.
We found Bd infection in 15% of the specimens we tested using real-time PCR. 8 out of the 11 species were found to have at least a low level infection. Of the 440 specimens analyzed, 40 tested positive for chytrid DNA before 1986. This observation raises more questions about the fungus’ role in declines and if it is endemic to the area.
Bd may be endemic to many parts of the world and is proliferating due to climate change that positively effects the life cycle of the fungus, while negatively effecting the life cycle of amphibians. Histological examination of positive specimens will be performed to confirm that animals were infected as early museum records date.