Present status of Odonata species in the Ogasawara Islands and conservation effort to preserved endangered endemic species

Abstract

The five endemic species of Odonata inhabiting the oceanic islands of Ogasawara have been rapidly declining from the mid-1980s. The reason for that decline is likely due to predation by an invasive alien species, ‘green anoles’. Currently, almost all the endemic Odonates have gone extinct from the main islands of Chichi-jima and Haha-jima. Although these endemic Odonates have still managed to survive in a few satellite islands, there are only small aquatic habitats which readily dry up when severe droughts hit Ogasawara.
Our recent efforts to construct artificial conservation ponds in these satellite islands appear to be effective. Three endemic species are currently breeding in those ponds, and the total population has increased.
Based on these encouraging results, we continue to stress the importance of an integrated action plan, including the development of areas protected from green anoles predation and the construction of more permanent ponds.