Distribution and Potential Spread of Amphibian Chytrid Fungus Batrachochytrium dendrobatidis in the Tasmanian Wilderness World Heritage Area

Chytridiomycosis is an emerging infectious disease caused by the pathogen Batrachochytrium dendrobatidis and has been linked to the decline and extinction of amphibian species throughout the world. B. dendrobatidis was first detected in Tasmania in 2004 and subsequently found in a range of urban and rural habitats in eastern and northern parts of the State. We report on a survey of the distribution of B. dendrobatidis within and around the Tasmanian Wilderness World Heritage Area (TWWHA). The TWWHA is a 1.38 million hectare area of significant fauna conservation value, which provides the majority of habitat for Tasmania’s three endemic frog species (Litoria burrowsae, Bryobatrachus nimbus and Crinia tasmaniensis). We surveyed 62 sites within and around the TWWHA including 33 sites within the boundaries of the TWWHA. B. dendrobatidis was found to cause oral chytridiomycosis in tadpoles of all four frog species surveyed (Litoria burrowsae, L. ewingii, Crinia signifera, and C. tasmaniensis). B. dendrobatidis was detected at 16 (26%) of the 62 sites surveyed, including 15 (52%) of the 29 sites surrounding the TWWHA and one of the 33 (3%) sites surveyed inside the TWWHA. The relatively low incidence of the disease within the TWWHA suggests that the majority of the TWWHA is currently free of the pathogen despite the region providing what appears to be optimal conditions for the persistence of B. dendrobatidis. For all survey sites within and around the TWWHA, the presence of B. dendrobatidis was strongly associated with the presence of gravel roads. The wide distribution of B. dendrobatidis in areas of Tasmania with high levels of human disturbance