Conservation of threatened endemic plants of the Ogasawara Islands

  • SDG15 Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss
Atsushi Kawakita
Graduate School of Science
Professor
The Ogasawara Islands, located approximately 1,000 km south of Tokyo, are oceanic islands that have never been connected to the continent, and harbor various endemic plants that underwent unique adaptations in the isolated environment. However, many endemic plants of the Ogasawara Islands face the risk of extinction due to forest development, invasion of non-native plants, and grazing by the goats introduced as livestock. Since the 1980s, the Botanical Gardens of the Graduate School of Science is actively involved in the conservation of the islands’ rare endemic plants by establishing methods to propagate the plants in greenhouses and reintroducing them in their local habitats. Since 2004, the project is being commissioned by the Ministry of the Environment based on “Act on Conservation of Endangered Species of Wild Fauna and Flora.” Although plant reintroduction is presently on hold to prevent introduction of plant pathogens and herbivores, we aim to recover the endangered plants in their native habitats by maintaining the quantity and quality of the plants conserved in our greenhouses and by gathering natural history information both in situ and ex situ, which would allow us to understand the causes of decline and to develop strategies for improving their long-term survival.
We maintain approximately 90 of the 125 endemic plant species of the Ogasawara Islands in our greenhouse.
The Botanical Gardens, Graduate School of Science
Melastoma tetramerum, endemic to Chichi-jima Island of Ogasawara. This species was reintroduced, and seedlings are propagating from the seeds of the reintroduced plants in its original habitat.
The Botanical Gardens, Graduate School of Science

Related links

Related publications

- Ideno T, Tanaka T, Komaki Y. 2017. Germination and growth after one year of the seeds of Pittosporum parvifolium sown under different environments. Bulletin of Japan Association of Botanical Gardens 52: 16-20.
- Ota Y, Komaki Y, Ideno T, Tanaka T, Makihara H, Hattori R, Masuya Y, Kitajima H, Shimada R. 2016. Cause of mortality of the endangered Pittosporum parvifolium endemic to the Ogasawara Islands. Tree and Forest Health 20: 133-137.
- Komaki Y. 2013. “Planting” in the conservation program of threatened endemic plants of the Ogasawara Islands. Bulletin of Japan Association of Botanical Gardens 47: 57-62.
- Ohi-Toma T, Komaki Y, Hirai K, Murata J. 2008. Current status of Melastoma tetramerum (Melastomataceae) and genetic assessment for future conservation. The Journal of Japanese Botany 83: 15-20.
- Hirai K, Komaki Y. 2008. On the conservation program of threatened endemic plants of the Ogasawara Islands. Bulletin of Japan Association of Botanical Gardens 42: 52-55.
- Iwatsuki K, Shimozono F. 1989. “Science to recover plants under the risk of extinction”. Kenseisha.

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