Nakajima Islands was added to Your Favorites!
Shikotsu-Tōya NP., Hokkaido
Claim this place to tell your story your way.
One male and 2 females were introduced to Nakajima between 1957 and 1965; no Ezo deer had lived there naturally. With no large predators or hunting on the island, their descendants multiplied and reshaped its forests.
Nakajima is 4 named islands atop a volcanic group of 11 lava domes. Geological mapping includes a dome now submerged as a reef about 1.2 km northeast of Oshima—one more volcanic feature hidden beneath the lake.
In 1666, the monk-sculptor Enkū placed a Kannon image on Kannon Island, giving the island its name. The 56.7-cm statue survives and is now preserved at the local museum at Usu Zenkoji.
A 2002–04 survey recorded 150 vascular plant species on Nakajima, compared with 460 in 1977—just 32.6% as many. Researchers linked the decline to decades of heavy Ezo deer browsing.
Nakajima’s famous Sakhalin spruce stood 31 m tall, with a trunk circumference of 3.99 m, and was selected for Japan’s “100 Forest Giants.” Typhoon 18 toppled it in September 2004; seedlings were carefully raised afterward.
Researchers found few birds that favor dense undergrowth, including Japanese bush warblers, in their Nakajima survey. Ground-dwelling Asian stubtails were more prominent: recordings captured 11,021 songs over 525 hours.
Benten Island is also recorded by the park visitor center as Toppu-moshiri (トップモシリ), “Sasa Island,” an Ainu name. A Benzaiten shrine has stood there since the late Edo period.
Along Oshima’s trail, cool air seeps from gaps between piled rocks at a feature called a fuuketsu, or “wind hole.” The geopark describes it as a small, hands-on clue to the volcanic landscape beneath the forest.
The smallest island, Manju, is also called “Snake Island.” The visitor center records a traditional warning that mamushi pit vipers were so numerous people should not land there—a local story, not a current wildlife count.
As Ezo deer numbers fell from 2009 to 2019, soil nitrogen measures rose in sampled forest plots but dropped in grassland. Researchers suggest recovering leaf litter boosted the forest, while fewer droppings and plant remains changed the grassland.
