Threatened Malagasy amphibians and reptiles in zoos – a call for enhanced implementation of the IUCN’s One Plan Approach

Madagascar is home to 370 native amphibian and 420 native reptile species with an extraordinary
high endemism rate of approx. 98%. Less than half (39%) of Madagascar’s amphibian and less than a third (32%) of Madagascar’s reptile species are currently evaluated as threatened by the IUCN (2021). We investigated for which threatened endemic Malagasy amphibian and reptile species ex situ populations in zoological institutions already exist, and which threatened species are not yet covered by ex situ conservation measures. We thus have surveyed species kept in zoological institutions, analysed the number of species held, the number of individuals per species, the number of zoos keeping a species, and those with breeding success in the past 12 months by retrieving data from the Zoological Information Management System (ZIMS, 2021). These data were supplemented with data from the European database Zootierliste (ZTL). In addition, a richness analysis was performed to find out how zoos keeping Malagasy amphibian and reptile species are distributed at a global scale. According to our analysis of ZIMS data, only 36 endemic Malagasy amphibian species
(9.7%) (37 if considering data from ZTL database) are globally kept in zoos. Ten of them are threatened, which amounts to only 6.9% of the 145 endemic and threatened Malagasy amphibian species. As such, it is likely that more than 93% of the threatened endemic Malagasy amphibian species (135) currently do not benefit of any ex situ conservation component. Our analysis revealed that there is a higher percentage on Malagasy reptile species kept in zoos in comparison to amphibians. Considering both, ZIMS and ZTL analyses, 97 endemic Malagasy reptile species (23%) are globally kept, 27 of which are threatened, which amounts to 20% of the 133 endemic Malagasy reptile species that are threatened. This implies that 80% of the threatened endemic reptile species (106) from Madagascar currently have no ex situ conservation component at the time of this survey. Of the 36 endemic Malagasy amphibian species and the 87 endemic reptile species kept in ZIMS zoos worldwide, only eleven amphibian species (30.5%) and 34 reptile species (39%) have reproduced within the last 12 months. Finally, only four (36%) of the bred amphibian species are threatened taxa, and of the reptile species bred, only thirteen (38%) are threatened. Only zoos in Europe and North America are currently playing a major role in keeping Malagasy herpetofauna. To optimise management and conservation efforts in zoos, refocusing on threatened and micro-endemic species, and reviewing their stocks accordingly is highly recommended. In-country ex situ approaches have already been started for amphibians and reptiles. However, extension of insurance populations among various institutions abroad should be seen as an essential contribution to be better prepared for catastrophic events potentially affecting local facilities or natural populations. Together
such a strategy complies with the One Plan Approach proposed by the IUCN SSC Conservation Breeding Specialist Group (CBSG), viz. the development of management strategies and conservation actions by all responsible parties for all populations of a species, whether inside or outside their natural range. With this analysis we aim to provide a basis for improved ex situ conservation breeding measures and develop a conservation breeding network for the threatened endemic species of the Malagasy herpetofauna.