Southern Darwin’s frog
This month, the spotlight falls on an amphibian discovered by naturalist Charles Darwin.
What are its biggest threats? What’s unique about Darwin’s frog?
Darwin’s frogs live in central and southern Chile and parts of Argentina, inhabiting temperate rainforests, often along the banks of streams. They are the only amphibians practicing vocal sac brooding, where male frogs scoop fertilised eggs into their mouths before manoeuvring them into their vocal sacs for safekeeping, where they remain for 65–85 days. The southern Darwin’s frog, Rhinoderma darwinii, is the only species still hanging on in the wild – its northern counterpart, Rhinoderma rufum, hasn’t been spotted in decades. Habitat loss and land conversion. Monoculture tree farms have replaced much of Chile’s temperate rainforests, with pine and eucalyptus trees gaining popularity for their ability to grow quickly and yield cash crops. But the country’s wild animals rarely inhabit single-species tree groves, and pine needles and eucalyptus leaves alter the water chemistry of drainage systems.
What about Chytridiomycosis?
This infectious fungal disease has caused dramatic amphibian declines in many parts of the world and has made its way to Chile, where it has infected some Darwin’s frogs. Invasive species are also an issue – for example, African aquatic frogs, imported for the pet trade, carry diseases and compete with native amphibians for resources.
Can conservationists save the Darwin’s frog from extinction?
We’re fighting against the development of hydroelectric dams, monitoring the spread of wildlife diseases, and working to maintain current forest preserves. To prevent extinction, assurance colonies of the most endangered species must be established with captive reproduction programmes. If we eliminate disease in wild habitats, the offspring of assurance colonies can repopulate protected forests. For 11 years, the Chilean Amphibian Conservation Center (CACC) has bred the Southern Darwin’s frog in captivity at two centres. It will open a third laboratory at Austral University in Valdivia, Chile, in February 2019. Millie Kerr
Male Darwin’s frogs carry fertilised eggs in their vocal sacs until the froglets are ready to venture into the world.