Reintroduction of the Kihansi Spray Toad Nectophrynoides asperginis Back to its Natural Habitat by Using Acclimatizing Cages

Abstract

The Kihansi Spray Toad (Nectophrynoides asperginis) is considered to be extinct in the wild. Captive breeding populations exist in Bronx and Toledo zoos in USA and in two captive breeding facilities in Tanzania. Efforts to reintroduce the species back to its natural habitat at Kihansi Gorge wetlands have become a long process. Both ex-situ and in-situ experiments have revealed promising outcomes but when the toads are freely (hard) released in the wetlands they disperse widely and detection becomes difficult.  Cages for acclimatising the toads before hard release have been constructed in two of the Kihansi Gorge spray wetlands. Factors such as density dependence, predators, food availability and diseases have been identified of concern to successful reestablishment of the species in its natural environment. The use of large cages (60 m²), close monitoring and partial control of the factors as a new approach has shown promising results at present and for future reintroduction processes of the Kihansi Spray Toad.

Keywords: Kihansi Spray Toad; Reintroduction; Hard release; acclimatizing cages