In the 20th century, a new infectious disease emerged and caused an unprecedented environmental catastrophe. Chytridiomycosis, a fungal skin infection, has compounded an amphibian extinction crisis driven by habitat loss, overharvesting and pollution, resulting in 40 per cent of amphibians being threatened with extinction.
Today, over 20 years after the first chytrid fungus was described, we remain largely helpless when chytridiomycosis emerges in a new area, with no widely applicable mitigation measures and no treatment that offers long-lasting protection. As a last resort, many amphibian species have been saved by establishing ex situ captive populations – how can we return them safely to the wild?
A global amphibian ark
When I first stepped behind the scenes of a zoo’s herpetology department, as a student keeper, I knew that I would meet animals facing threats like pollution, habitat destruction, and a voracious pet trade. I wasn’t expecting to see amphibian after amphibian, tank after tank, being kept solely out of sheer, fierce hope. Safely cocooned in miniature, curated forests and streams are little communities, upon whose existence entire species depend. Members of The Amphibian Survival Alliance, a partner of Synchronicity Earth, are helping these families ride out the waves of a mass extinction event beyond their doors, hoping that one day their descendants will be safe outside the confines of these arks. The problem is that these animals are threatened by disease. That disease, chytridiomycosis, lives on in the soil of the forests and the waters of the streams long after its victims have gone; once it’s arrived – likely hitchhiking on a pet, a frog destined for a laboratory, or in some undisinfected water discarded down a drain – it is nearly impossible to eliminate. Their habitats may look pristine, but they cannot be made safe.
“The impact of chytridiomycosis on frogs is the most spectacular loss of vertebrate biodiversity due to disease in recorded history” – Skerratt et al., 2007
Chytridiomycosis is caused by two species of microscopic fungi. Batrachochytrium dendrobatidis (Bd) was isolated in 1998 from the skin of a Blue Poison Dart Frog that died mysteriously in a zoo. Then, in 2014, Batrachochytrium salamandrivorans (Bsal), literally the salamander-devourer, was identified in the Netherlands. The arrival triggered collapses of fire salamanders, killing around 96% of the country’s population.
