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Ogasawara Islands

Les noms des biens figurent dans la langue dans laquelle les Etats parties les ont soumis.

Japon (Asie et pacifique)

Date de soumission : 30/01/2007
Critères: (viii)(ix)(x)
Catégorie : Naturel
Soumission préparée par :
Ministry of the Environment
Etat, province ou région :

Tokyo


Coordonnées
N27 05 24 E142 11 42
Ref.: 5095

Description

The Ogasawara Islands refer to a group of islands, which stretch for 400 km from north to south, lying in the Northwest Pacific south of the Japanese archipelago. They consist of the Ogasawara archipelago, the Volcano (Iwojima) Islands and several isolated islands. The Ogasawara archipelago is composed of the three island groups, i.e. Chichijima Islands, Hahajima Islands and Mukojima Islands. According to Udvardy's classification of biogeographical provinces (1975), they belong to the Micronesian Province (5.2.13) of the Oceanian Realm, and their characteristic biome is in the group ‘Mixed island systems'. The Ogasawara Islands located roughly 1000 km from the Japanese archipelago and about 550 km from the Mariana Islands, and they are all oceanic islands that have never been connected to a continent since their formation. In terms of area, Chichijima is the largest at only about 24 km2, and most of the islands are uninhabited islands of less than 10 km2. The highest peak is 916 m on Minami Iwojima. The climate is warm all year round and the annual mean temperature is 23.0°C on Chichijima where the mean temperature is 18.7°C even in winter. The annual rainfall is 1,280 mm with a slightly higher precipitation in May and November.

Until 1830, the Ogasawara Islands were uninhabited and called "Muninjima" (meaning "uninhabited island") which transformed into the English name of Bonin Islands. Since they had been free from human activities until recently, the ecosystem of oceanic islands has been well preserved. At present, there are about 2,300 inhabitants in Chichijima and Hahajima, and roughly 17,000 tourists visit annually being attracted by the unique ecosystem of the islands and the beautiful ocean.

The Ogasawara archipelago comprises island arc volcanoes formed about 48 to 44 million years ago. Significantly, it is the only subaerial place in the world that records an early stage of formation of oceanic island arc in response to the beginning of subduction of an oceanic plate (Pacific plate). The Volcano Islands, on the other hand, are younger (less than 2 million years old) arc volcanoes beneath which continental crust formation is currently in progress. Research on the geological evolution of the Izu-Ogasawara arc-trench system led us to the idea that continents originated from oceanic island arcs.

In the Ogasawara Islands, fauna and flora have diverse origins, and through a unique evolutionary process, a large number of endemic species have developed. Many of them escaped from extinction and demonstrate the ongoing process of evolution. Especially, the Distylium dry scrubs (a kind of sclerophyllous forest) are habitats of many endemic and rare species. In addition, the Ogasawara Islands are important breeding sites for tropical seabirds.

Valeur universelle exceptionnelle

Satements of authenticity and/or integrity

The Ogasawara Islands show the formation process of an oceanic island arc from its birth through its infancy and to the current young period. They also preserve the evolutionary process of life on oceanic islands and serve as an important habitat for valuable and endangered species. The site planned for nomination includes all the elements necessary to express its outstanding universal value mentioned above and is of sufficient size to maintain the value.

The site has adequate long-term legislative and regulatory protection by designation of National Park, Wilderness Area, Forest Ecosystem Reserve and National Wildlife Protection Area. In addition, many species are protected as Natural Monuments or National Endangered Species, and Programs for Rehabilitation of Natural Habitats and Maintenance of Viable Population have been implemented for some endemic species.

Furthermore, a regional liaison committee and a scientific council have been set up. The regional liaison committee consists of the relevant agencies that have jurisdiction over the protected areas mentioned above, municipalities and related groups. The scientific council provides advice on the conservation and management of the site from a scientific perspective. With due consideration of the advice from the scientific council and the consensus of the regional liaison committee, the administrative authorities are going to formulate a management plan covering the entire area planned for nomination.

In order to protect endemic species against alien species, all the related agencies are currently making concerted efforts including the pest control projects based on the Invasive Alien Species Act. Also, efforts are underway to promote proper tourism. For example, Tokyo Metropolitan Government and Ogasawara Village signed agreement and established use rules based on the Guidelines for the Protection and Appropriate Use of Nature on the Islands of Tokyo.

Comparison with other similar properties

The birth of an oceanic island arc and the production of boninite magma are not unique processes to the Izu-Ogasawara arc but universal phenomena that have been repeated countless times in the history of the Earth; however, most records have been obliterated by the subsequent tectonic disruption. The Izu-Ogasawara-Mariana arc, on the other hand, preserves the boninite submarine volcanoes along the Izu-Ogasawara-Mariana trench that extends 2500 km to the south of central Japan. Unfortunately, the vast majority of the boninite volcanoes lie beneath the inaccessible 3000 meters of water. The Ogasawara Islands are the only place where we can see boninite and transitional volcanic products that record the entire growth process of an oceanic island arc from its birth to its present young stage as well as the type locality of boninite.

The existing World Natural Heritage sites that maintain the features of oceanic islands and display the process of evolution include the Galápagos Islands (Ecuador), the Hawaii Volcanoes National Park (United States) and the Aldabra Atoll (Seychelles). The Ogasawara Islands differ in origin from these other islands of hot spot or atoll origins, and were formed in the older era. Furthermore, unlike the Galápagos Islands, where species are almost exclusively of South American origin, the Ogasawara Islands are distinct in that the plant species of diverse origins coexist, consisting of Oceania, Southeast Asia and Honshu types. The Ogasawara Islands are far smaller than these other sites, but the endemic rate is comparable to that of these areas and the number of native species per unit area is larger.

There is no existing World Natural Heritage site located in the same Udvardy's biogeographical province as the Ogasawara Islands. Among the areas not on the World Heritage list, the Mariana Islands (United States) are in the same biogeographical province. However, since the Northern Mariana Islands were formed later than the Ogasawara Islands, the level of biodiversity is relatively low. While the Southern Mariana Islands make up an island arc that was formed in the same period as the Ogasawara Islands, they have been covered with coral reefs, making it impossible to sufficiently observe the topographical and geological features. In addition, as a result of development, they have lost ecosystems unique to oceanic islands that the Ogasawara Islands maintain.

As described above, there is no other area that has the similar value to the Ogasawara Islands.