The Wildlife Conservation Society’s Bronx Zoo, the Toledo
Zoo, Tanzanian government, World Bank and other partners reintroduced
2,000 Kihansi spray toads into the Kihansi Gorge in Tanzania in October. This
is the first example of an amphibian species that had been declared extinct in
the wild being reintroduced into its native habitat.

The repatriation effort marks a major milestone for a
species declared extinct in the wild in 2009. It is the result of a 12-year
partnership to breed the toads in captivity while its habitat was
restored. 

 “The WCS Bronx Zoo has been working with our partners
for more than a decade to save the Kihansi spray toad with the ultimate goal
of  reintroducing it back into the wild,” said Jim Breheny, Executive Vice
President and General Director of WCS Zoos & Aquarium and Director of the
Bronx Zoo. “The curators in the Bronx Zoo and in the Toledo Zoo – whose
expertise allowed them to develop a successful husbandry and propagation
program for these unique little toads – have helped to ensure the
reintroduction of an important living component back into the Tanzanian
ecosystem.”

The Kihansi spray toad 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 was predicted
to dramatically change the Kihansi spray toad’s habitat. The micro-habitat
where the toad lived was dependent on the mist created by the waterfalls in the
gorge. The dam, generating nearly one-fourth of Tanzania’s electrical supply,
reduced the flow of the Kihansi falls by 90 percent, drastically lessening the
mist zone.

The toad was last seen in the wild in 2005, and in 2009, it
was declared extinct in the wild by the IUCN. Although the ultimate cause for
extinction is still debated, it is likely a combination of habitat change and
the emergence of chytrid fungus, a virulent pathogen which is responsible for
alarming population crashes and extinctions of amphibian species across the
world.

As the spray toad population rapidly declined, an agreement
between WCS and the Tanzanian government was reached. Bronx Zoo scientists and
Tanzanian officials collected an assurance colony of 499 Kihansi spray toads
from the gorge. The small colony was brought back to the U.S. to initiate
the off-site conservation program. Special microhabitats meeting all the
environmental parameters necessary for the toads to survive were replicated in
bio-secure facilities at the Bronx Zoo and later the Toledo Zoo. Both zoos were
successful in breeding the toads and increasing their numbers so reintroduction
efforts could commence.

Said Dr. Cristián Samper, WCS President and CEO: “The
reintroduction of the Kihansi spray toad to the Kihansi Gorge is a momentous
achievement in conservation. It clearly shows how zoos can play an important
role in conservation. This has been a truly global effort to save a species.
This project proves that through partnership and science – wildlife can
prevail.”

In 2010, 100 Kihansi spray toads were returned to Tanzania,
where a propagation center at the University of Dar es Salaam allowed for the
establishment of a third assurance population and  preparations for the
species’ eventual repatriation.

The Bronx and the Toledo zoos will continue to maintain an
assurance population of the spray toads and have them on exhibit for visitors
to see. The released toads and habitat will be closely monitored to ensure that
environmental conditions remain favorable and to evaluate the progress of the
animals. Additional releases may occur periodically to bolster the number of
toads with the hope of having a viable, self-sustaining population.

Photo Credits:  Julie Larsen Maher (first, second, and fifth photos), Alyssa Borek (third and fourth photos)