The Washington Post reported this week that the Bronx Zoo and the Toledo Zoo plan to release hundreds of Kihansi spray toads into their native habitat in Tanzania. The species was discovered in 1996, living in an area spanning just five acres around Kihansi Gorge, doused in the constant mist of Kihansi Falls. When the river there was dammed in 2000 for a hydroelectric project, the size of the waterfall dropped by 90%, and the toad population plummeted.
In an effort to save the species from extinction, scientists from Wildlife Conservation Society (WCS) and Tanzanian authorities collected an “assurance colony” of 499 toads from the area and transported them to the United States. They were distributed to a number of zoos around the country, where scientists attempted to raise and breed them in captivity. The Toledo and Bronx Zoos were the only ones that were able to successfully care for and breed the new arrivals. In 2010, 100 individuals from the US zoos were moved to the University of Dar Es Salaam to establish another assurance colony there.
The last Kihansi spray toad was seen in the wild in 2004 and the species was declared extinct in the wild in 2009. In addition to habitat loss, scientists believe the chytrid fungus, a major threat to amphibian species worldwide, added to the population’s demise.
The captive management effort for the Kihansi spray toad is part of a larger program dubbed “Amphibian Ark,” a global effort launched in 2007 to save 500 amphibian species from extinction by creating captive populations. The goal is to eventually reintroduce each species to the wild, and scientists hope that the reintroduction this week will mark a new beginning for this one.
According to Cristian Samper, President and Chief Executive of WCS, “The reintroduction of the Kihansi spray toad to the Kihansi Gorge in Tanzania is a momentous achievement in conservation. It clearly shows how zoos play an important role in conservation. This project shows that through partnership and science, wildlife can prevail.”