A rare toad from Tanzania declared “extinct in the wild” three years ago has been restored to its original habitat.
This is the first time an amphibian species has been returned home after being classified as “extinct in the wild”.
The Kihansi Spray Toad, native to just two hectares of land in south-central Tanzania, became extinct after the installation of a hydroelectric dam dried up the “spray meadows” it relied upon for survival. “Spray meadows” exist at the base of waterfalls, where the fine mist of water produced by the falls helped the Kihansi toad thrive.
A successful captive breeding program at the Bronx and Toledo Zoos in the US meant that while the toad was extinct in the wild, 6000 survived in captivity. An initial population of 2500 toads has been rehabilitated in Tanzania.
An expansive misting system, designed to recreate the conditions in the habitat before the construction of the dam, has been installed in the area, paid for by the World Bank and the Norwegian government.
Australian conservationist Dr Euan Ritchie says cases such as the Kihansi Spray Toad’s can galvanise public sentiment towards environmental causes.
“What is interesting about these cases is they inspire the public about what we can do in conservation to make amends for the impact we all have on our environment,” he said.
But the Deakin University academic argued high profile cases such as these can also raise thorny questions about which species humans choose to protect, and why.
“No one will question that it’s a wonderful achievement, but it raises the whole topic of ‘ecological triage’, and how we best invest our money and effort. Should we prioritise this toad species over many hundreds of thousands of other species which also need our help?”
“It’s a very difficult and emotional topic and I don’t think anyone’s got a perfect solution.”
Still, Ritchie says the case provides a strong case for rehabilitation of Australia’s endangered species. Restoring the endangered bilby to areas where it has gone extinct will have untold benefits for local environments, he argues.
La Trobe Univeristy’s Head of Environment and Ecology, Dr Susan Lawler, says the costs of rehabilitation can be prohibitive.
“Conservation efforts do cost money so this is something that will need continuing funding, because they’ll have to maintain the misting system forever.”
She is also concerned about other species that may not receive as much public attention, but remain vital to the health of ecosystems.
“It tends to be the invertebrates that suffer. People underestimate the value of things without backbones. An endangered cricket or worm is not going to get the airtime or the funding, but they may be absolutely critical to the environment.”
Both Ritchie and Lawler agree that the best way to protect species such as the spray toad is to prevent habitat destruction in the first place.
“A bigger question,” Ritchie said, “is what do we as humans learn from success stories such as this; are we really prepared to change our ways sufficiently to prevent further species becoming endangered?”