Kihansi spray toads make historic return to Tanzania

Published: Tuesday, August 17, 2010 - 10:46 in Biology & Nature

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A diminutive Kihansi spray toad newborn rests on the back of an adult female. Reared at the Wildlife Conservation Society's Bronx Zoo, these amphibians -- now extinct in the wild -- are part of an international program to reintroduce the Kihansi spray toad back into its former habitat in Tanzania.
Julie Larsen Maher/Wildlife Conservation Society

In a bold effort to save one of the world's rarest amphibians from extinction, one hundred Kihansi spray toads have been flown home to Tanzania after being painstakingly reared at the Bronx Zoo and The Toledo Zoo working in close partnership with the Tanzanian government and the World Bank. The toads now reside at a new, state-of the-art propagation center in Dar es Salaam, Tanzania's commercial capital, with the eventual goal of reintroducing the tiny amphibians into their former habitat.

"On behalf of the Government of the United Republic of Tanzania, we are very grateful to the Bronx Zoo and The Toledo Zoo for taking care of these precious toads (KST) for ten years, and now they have safely arrived home via KLM flight and all 100 toads are cheerful as witnessed by our Tanzanian trained KST keepers at the facility at UDSM Zoology Department. We are very optimistic that they will acclimatize soon and be taken to their homeland in Kihansi Gorge in the near future," said Anna Maembe on behalf of the Government of Tanzania.

According to Dr. Anne Baker, The Toledo Zoo's Executive Director and CEO, "We are extremely proud of the staff members, curators, and keepers whose expertise in scientific husbandry made this tremendous accomplishment possible. The level of collaboration involved here—from the World Bank, the Tanzanian government, and the participating zoos to the Tanzanian field biologists and students who shared their knowledge with us—has been nothing short of inspiring."

"The return of these special creatures to Tanzania is a landmark achievement for the Bronx Zoo, the Tanzanian government, The Toledo Zoo, and the World Bank," said Jim Breheny, Director of the Bronx Zoo and Wildlife Conservation Society Senior Vice President of Living Institutions. "For years, the Bronx Zoo has been anticipating this important step toward reintroduction of the species, and we are ecstatic that the first toads are thriving in the new facility."

"This is an important step that has been achieved through a lot of hard work. The Bank has financed Tanzania's commitment to save the Kihansi Spray Toad (KST) for nearly a decade, and has been looking forward to a successful reintroduction, which will be a measure of the recovery of the ecosystem and the success of the Lower Kihansi Environmental Management Project (LKEMP). While we remain optimistic about a successful reintroduction, we acknowledge individual and collective efforts and commitment of all players in this project from within and outside Tanzania," said Jane Kibbassa, Task Team Leader for LKEMP.

The Kihansi spray toad's unique odyssey began shortly after the species was first discovered in 1996 living in a five acre micro-habitat created by the spray of nearby waterfalls in the Kihansi Gorge.

In 1999, the construction of a hydroelectric dam in the gorge dramatically changed the Kihansi spray toad's habitat. Although this dam is vital to the Tanzanian economy in that it generates one-third of Tanzania's total electrical supply, its construction reduced the original size of the Kihansi falls to 10 percent of its former flow, drastically lessening the mist zone in which the toads thrived.

Following an agreement between WCS and the Tanzanian government and with funding from the World Bank, which constructed the dam, scientists and Tanzanian officials collected an assurance colony of 499 Kihansi spray toads from the gorge.

The toad was last seen in the wild in 2004, and in 2009 the toad was declared to be extinct in the wild by the by the International Union for the Conservation of Nature.

Today, 5,000 toads live at The Toledo Zoo and 1,500 reside at the Bronx Zoo. Both zoos will continue breeding and exhibiting the animals, returning additional shipments to Tanzania as their numbers rebound.

The Tanzanian government has been managing the Lower Kihansi Environment Management Project in the gorge. A system of sprinklers, replicating the toad's habitat, has been installed in preparation for the species' return. The ultimate goal is to return the toads to their natural habitat within the gorge.

Scientists are still debating the ultimate cause of extinction of this species in the wild, but theorize a combination of habitat change, pesticide exposure, and the emergence of infective chytrid fungus led to their demise. Chytrid is responsible for alarming crashes and extinctions of amphibian species in many parts of the world.

A species unusual among toads – females give birth to live, fully-formed young, rather than laying eggs that hatch into free-living tadpoles.

Source: Wildlife Conservation Society

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