A frog comeback – is it possible?

Meet a very special frog population carrying hope for their species. Deep in the damp forests on the islands of Dominica and Montserrat, one of the world’s largest frog species is hanging on by a thread. The mountain chicken frog (you’ll never guess what it tastes like) has suffered from habitat loss, overhunting, and a far more insidious foe that threatens to tip them over the edge.

All across the world, we’re going through an amphibian apocalypse. Over 90 species are extinct already, wiped out by the chytrid fungus. “The organism/disease is often referred to as the worst ever wildlife disease threat to a taxonomic class ever recorded,” reports Richard Gibson, Auckland Zoo’s Head of Life Sciences. “Species are not equally susceptible, fortunately, so we will not lose all amphibians, but we may continue to lose additional sensitive species.”  When the chytrid fungus arrived in Montserrat, the Mountain Chicken population collapsed, wiping out more than 80% of the population in less than a year. 

Fifty remaining frogs were rescued, sent to the care of the Durrell Wildlife Conservation Trust to join a captive breeding program. Now some of their descendants are stepping foot back on their island. “Normally we would only propose reintroductions where the threats have been mitigated first – e.g. predators removed, habitat restored, pollutants cleared up, etc – but in the case of chytrid we usually don’t have this luxury as the chytrid can survive in the environment without amphibians.” Richard says. “This is why the mountain chicken project on Montserrat is so unusual… it’s trying to reintroduce a species to the environment despite the known and proven threat still being current.”

Under the guardianship of the Durrell Wildlife Conservation Trust and with funding from the Auckland Zoo Conservation Fund, the new arrivals on Montserrat are part of a ground-breaking experiment using a semi-wild environment. “Currently, there is no known method for eradicating chytrid from the wild.” Says Dr Mike Hudson, project leader. “We have had to think outside the box and come up with a mechanism for enabling frogs to survive alongside the fungus in their natural environment.” The ‘safe haven’ semi-wild environment is equipped with solar powered heated ponds, that raise the temperature beyond what the chytrid fungus can tolerate, giving the frogs safety, even if the fungus can’t be wiped out from their habitat. With the ‘safe haven’ experiment up and running, long term monitoring of these frogs will allow scientists to determine whether these protected refuges could keep the Mountain Chicken population safe.  If this approach works for the Mountain Chicken, they may light a path to safety for many other species under threat from the amphibian apocalypse, making this experiment extremely important.

This work is also providing benefits for the whole ecosystem around it. As part of caring for this establishing population, the Durrell Wildlife Conservation Trust has also created an insect breeding facility, so that the mountain chicken frogs can receive supplemental feeding if necessary. This also promises to be a fantastic resource for helping the Montserrat galliwasp, a critically endangered lizard that shares the island with the mountain chicken frogs. While establishing colonies of insects, researchers prioritised choosing endemic, native species that would be natural prey items, and could also benefit from having breeding colonies to buffer wild populations. In the process, they found what seems to be an undescribed species of cockroach. It has “a very attractive scent, unusual for a cockroach!” If this is a new species, at least now there’s already a captive breeding program for it! It’s a remarkable example of how a recovery program for one species can benefit the whole ecosystem and have unexpected side discoveries.

Auckland Zoo is looking forward to hearing from our partners when the data on this crucial safe haven experiment is released! Hopefully in the future the strange bark-croak of the mountain chicken frog will still echo through the wild spots of Montserrat. In the meantime you can get up close to some awesome amphibians at Auckland Zoo like the green and golden bell frogs hiding in the goliath stick insect habitat in Strangely Beautiful Australia.

If you want more information on the chytrid fungus and the worldwide efforts to save amphibians, there is some great information at the Amphibian Ark, the IUCN’s Amphibian Specialist Group, or the Amphibian Survival Alliance. Or, ask our ectotherm zookeepers if you see them at the zoo!

Every time you visit Auckland Zoo, or donate to our Conservation Fund, you’re directly helping to fund Wild Work like this in New Zealand and Worldwide. Thank you for helping us to save wildlife in wild places!