An estimation of number of birds to be consecutively released in the reintroduction of Japanese Crested Ibises /Une estimation de la quantite d'oiseaux a liberer consecutivement lors de la reintroduction de l'Ibis Nippon (Nipponia nippon)

• Published in: The Wilson journal of ornithology Vol. 130; no. 4; p. 874
• Main Authors: Wajiki, Yuichi, Kaneko, Yoshinori, Sugiyama, Toshie, Yamada, Takahisa, Iwaisaki, Hiroaki
• Format: Journal Article
• Language: English
• Published: Wilson Ornithological Society 01.12.2018
• Subjects: Biodiversity conservation; Biological diversity conservation; Japanese ibis; Methods; Ornithological research; Wildlife reintroduction; Japan
• ISSN: 1559-4491

The Japanese captive population of Crested Ibis (Nipponia nippon) has rapidly increased, and reintroduction programs were initiated on Sado Island in 2008. The Japanese captive population, however, was founded by only 5 individuals originating from the Chinese captive population. Because efforts were directed toward preserving genetic diversity in the captive population, it was appropriate to consider genetic diversity in the reintroduced population to evaluate its potential to survive in the wild, where environmental changes are more significant than in captivity. The purpose of this study was to determine the number of individuals to release in the future to preserve genetic diversity of the reintroduced population. We simulated the probability that the reintroduced population after 50 years would retain a rare allele existing in the captive population, based on demographic parameters obtained from either the Japanese captive or reintroduced populations, or Chinese wild populations. As a result, the 10-15 individuals currently released in the annual reintroduction would be the number needed to be released each year over 50 years to retain the rare allele with a frequency in the captive population of 0.05 with a >90% probability. Therefore, the current reintroduction program seems reasonable and should be continued. Received 2 July 2017. Accepted 7 July 2018. Key words: allelic diversity, genetic diversity, Japanese Crested Ibis, reintroduction, release number. La population captive japonaise d'Ibis Nippon (Nipponia nippon) augmente rapidement et les programmes de reintroduction ont commence sur File de Sado en 2008. La population captive japonaise a ete etablic par seulement cinq individus, originaires de la population captive chinoise. Les efforts ont ete orientes a la protection de la diversite genetique dans la population captive ; donc, il convient de considerer la diversite genetique dans la population reintroduite vers la survie de la population sauvage ou les changements ecologiques sont plus importants qu'en captivite. Le but de cette etude etait de determiner la quantite d'individus a liberer dans le futur pour proteger la diversite genetique de la population reintroduite. Nous simulames la probabilite si la population reintroduite conserverait un allele rare existant dans la population en captivite apres 50 annees, sur la base de parametres demographiques de populations japonaises (captive ou reintroduite) ou sauvage chinoise. En consequence, nous suggerons que 10 a 15 individus--qui etaient liberes recemment lors de la reintroduction annuelle--devraient etre liberes chaque annee dans les 30 prochaines annees pour conserver 1'allele rare dans la population reintroduite a la meme frequence comme la population captive (0,05) avec une probabilite de plus de 90%. Par consequent, le programme de reintroduction actuel semble etre raisonnable et il doit continuer. Mots-cles: diversite genetique. Ibis Nippon, quantite de lacher, reintroduction, richesse allelique.