Kihansi spray toad

Between July 2000 and March 2001, gravity-fed artificial spray systems were built and placed in three areas of spray wetlands that were affected by the Kihansi Dam. These spray systems functioned to mimic the fine water spray that had existed prior to the diversion of the Kihansi river, maintaining the microhabitat. The installation was initially successful in maintaining the spray-zone habitat, but after 18 months, marsh and stream-side plants retreated and a weedy species overran the area, changing the overall plant-species composition.[6] The next steps in environmental management included ecological monitoring, mitigation, establishing rights of water authority and Tanesco to implement hydrological resources for conservation of the Kihansi spray toad and spray wetlands habitat.[6]

An ex situ breeding program is maintained by North American zoos in the effort to reintroduce the species back into the wild. The program was initiated in 2001 by the Bronx Zoo when almost 500 Kihansi spray toads were taken from their native gorge and placed in six U.S. zoos as a possible hedge against extinction.[10][11][12] Initially its unusual life style and reproduction mode caused problems in captivity, and only Bronx Zoo and Toledo Zoo were able to maintain populations.[11] By December 2004, fewer than 70 remained in captivity, but when their exact requirements were discovered greater survival and breeding success was achieved.[10][11] In November 2005, the Toledo Zoo opened an exhibit for the Kihansi spray toad, and for some time this was the only place in the world where it was on display to the public.[10] The Toledo Zoo now has several thousand Kihansi spray toads,[10][13] the majority off-exhibit. The Bronx Zoo also has several thousand Kihansi spray toads,[13] and it opened a small exhibit for some of these in February 2010.[11][14] In 2010 Toledo Zoo transferred 350 toads to Chattanooga Zoo,[10] which has created a small exhibit for them. Groups numbering in the hundreds are now also maintained at Detroit Zoo and Omaha's Henry Doorly Zoo.[13]

In August 2010, a group of 100 Kihansi spray toads were flown from the Bronx Zoo and Toledo Zoo to their native Tanzania,[10] as part of an effort to reintroduce the species into the wild, using a propagation center at the University of Dar es Salaam.[12][15] In 2012, scientists from the center returned a test population of 48 toads to the Kihansi gorge, having found means to co-inhabit the toads with substrates presumed to contain chytrid fungus.[16][17] The substrates were extracted from the Kihansi gorge spray wetlands, and mixed with captive toads with their surrogate species from the wild. Reintroduction commenced because its substrate appeared to not harbor any infectious agents that could threaten the survival of the species.[17] In 2017 a reintroduction program will be launched and currently a few Kihansi spray toads will be successfully reintroduced in Tanzania.

Despite strict protocols in the breeding facilities, toads are occasionally attacked by chytrid fungus, resulting in mass deaths at the Kihansi facility. Air conditioning and water filtration system malfunctions have also contributed to toad mortality. Researchers suggest that reintroduction of the species in the wild might take time because it needs to adapt slowly to the wild habitat in which it needs to search for food, evade predators, and overcome disease, in contrast to the controlled environment they lived in during captivity.[17]