Extinct in wild, tiny Tanzanian toad thrives in lab

Investigating ways to reintroduce them to their natural home

July 2011: A tiny species toad, which quickly became extinct in the wild after it was discovered in Tanzania, is thriving in a New York laboratory.

UNIQUE: The Kihansi spray toad

Scientists are trying to find ways to safely reintroduce the Kihansi Spray toad to its natural home in the Kihansi River Gorge in south-eastern Tanzania.

Dr James Gibbs, an ESF conservation biologist at the SUNY College of Environmental Science and Forestry (ESF) in Syracuse said: ‘This species, without the help of captive breeding, will go extinct. It's part of the natural heritage of Tanzania. This is a species that's extinct in the wild but it's right here in Syracuse.'

The toad was discovered in 1996 while a dam was being built on the Kihansi River. A population of the toads was found living near the bottom of a waterfall where the river plunged more than 3,000ft.

Their natural habitat is like living next to a fire hydrant
The toads lived in a nearly vertical wetland created by the forceful spray that came off the pounding water. Gibbs compared the environment to living next to an open fire hydrant.

‘There was a unusual species of amphibian found there,' he said. ‘And after much searching, it turned out to be a truly endemic and unique species. They have never been seen anywhere else. It might be the four-legged vertebrate species with the smallest range in the world.'

Construction of the dam resulted in reduced spray in the toads' habitat and their numbers quickly declined. Some 500 of them were removed to zoos in America, where they continued to decline until they population was finally stablised and then began to reproduce. Now, after dwindling to about 50 individuals, the captive population has rebounded.

The Tanzanian government would like to reintroduce the animals but they want to be sure the environment has been stabilised enough to provide a suitable habitat.

Concerns about pesticides and deadly fungus
Scientists are concerned about how a returned toad population might be affected by pesticides in the river, particularly endosulfan from upriver agriculture, and the chytrid fungus that is harming amphibians worldwide.

‘Nobody wants to put lots of toads back if they're going to suffer and not succeed in the restored habitat,' Gibbs said.
In an agreement with the National Environment Management Council of Tanzania, Gibbs and his team are researching the effect of the fungus and the pesticide, both together and separately, on the toads. ESF undergraduate Chelsae Radell is among those carrying out the study.

‘The reason the Kihansi spray toad has gone extinct in the wild is because of human impact,' Radell noted. ‘I think if humans are causing their extinction, then everyone should care a little bit.'