Hotspots, Conservation, and Diseases: Madagascar’s Megadiverse Amphibians and the Potential Impact of Chytridiomycosis

Abstract

Worldwide amphibian diversity is threatened through the emergence of the disease chytridiomycosis, caused by the amphibian chytrid fungus. This patho- gen apparently is absent from the amphibian hotspot Madagascar. However, an extinction risk assessment based on environmental niche modelling suggests that a major portion of this island is climatically highly suitable to the fungus. This includes regions of high amphibian species richness. Many species have their entire geographic range in such areas and are at the same time predicted to suffer potentially from chytridiomycosis due to their life history traits. Human-mediated dissemination of the chytrid fungus to Madagascar is considered likely. In particu- lar, there may be a high risk of accidental cointroduction via the animal trade. Severe decline and possibly extinction are expected in a postemergence scenario on Madagascar with more than 270 described and numerous undescribed anuran amphibian species under threat. Effective responses to this potential threat might include (1) an increased attention to ‘biosecurity’, including the consequent imple- mentation of measures to avoid the introduction of the chytrid fungus, (2) the development of breeding procedures for representatives of all major clades of Madagascan amphibians as a ‘pre-emergency prophylaxis’ and (3) the development of plans for ‘emergency response’.