Conservation Genetics

, Volume 13, Issue 3, pp 717–725 | Cite as

Population structure of an endangered frog (Babina subaspera) endemic to the Amami Islands: possible impacts of invasive predators on gene flow

Research Article


The otton frog (Babina subaspera) is an endangered species endemic to the Amami Islands, Japan. High predation pressure from an introduced carnivore, the mongoose, has caused declines in the frog populations and created a large habitat gap around an urban area. To promote effective conservation, we investigated the genetic status of the species and examined the effect of the habitat gap on gene flow among populations. Using five polymorphic microsatellite loci and mitochondrial DNA sequences, we investigated genetic diversity, genetic structure and gene flow in B. subaspera populations on the islands of Amami-Oshima and Kakeroma-jima. The expected heterozygosity (H E) within each locality was generally high (range: 0.67–0.85), indicating that B. subaspera maintains high genetic diversity. However, genetic differentiation was observed, and the two populations, TAG and KAR, showed little gene flow with other populations. The clustering and F ST analyses also predicted that these two populations were clearly distinct. According to the mitochondrial DNA analysis, the observed genetic differentiation occurred relatively recently. Possible barriers such as mountain ridges, rivers or roads did not result in genetic separation of the populations. These data support the hypothesis that the habitat gap created by an introduced predator prevented the gene flow among B. subaspera populations. When developing conservation strategies for B. subaspera, focus should be directed to these two isolated populations; careful monitoring of population size and genetic diversity should be conducted along with the mongoose elimination project ensues.


Conservation genetics Genetic diversity Habitat fragmentation Microsatellite Mitochondrial DNA Otton frog 



We would like to thank Setsuko Suzuki and Noe Matsushima for their advice. We also thank Yuya Watari and Saya Uemura for their help with field collection. Samples were collected under permits nos. 204 and 703 from the Kagoshima education commission. NI was supported by a Japan Society for the Promotion of Science Research Fellowship and Research Fund.


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Copyright information

© Springer Science+Business Media B.V. 2012

Authors and Affiliations

  1. 1.Forestry and Forest Products Research InstituteTsukuba IbarakiJapan
  2. 2.Ecohydrology Research Institute, The Tokyo University Forest, Graduate School of Agricultural and Life SciencesThe University of TokyoSeto, AichiJapan

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