Amami-Oshima Island, Tokunoshima Island, Northern part of Okinawa Island, and Iriomote Island

Outstanding Universal Value

Brief synthesis

Amami-Oshima Island, Tokunoshima Island, the northern part of Okinawa Island, and Iriomote Island is a terrestrial serial property covering 42,698 ha comprised of five component parts on four different islands (with Tokunoshima Island having two component parts). Influenced by the Kuroshio Current and a subtropical high-pressure system, the property has a warm and humid subtropical climate and is covered mainly with evergreen broadleaved subtropical rainforests.

The formation of the Okinawa Trough in late Miocene resulted in the separation of a chain from the Eurasian Continent, forming an archipelago of small islands. Terrestrial species became isolated on these small islands and evolved to form unique and rich biota. The islands included in the property support many examples of endemic species of terrestrial vertebrate groups and plants that were not able to cross between these islands or adjoining landmasses.

Thus, the property is of high global value for the protection of many endemic and globally threatened species, and contains the most important and significant remaining natural habitats for in-situ conservation of the unique and rich biodiversity of the central and southern part of the archipelago.

Criterion (x): The property contains natural habitats of outstanding importance for in-situ conservation of the unique and diverse biodiversity of the central and southern part of the archipelago in which the property is located. The five component parts constituting the property are located in one of the 200 ecoregions considered most crucial to the conservation of global biodiversity. The subtropical rainforests of the property are the largest remaining in the region and harbour a very rich flora and fauna, boasting at least 1,819 vascular plants, 21 terrestrial mammals, 394 birds, 267 inland water fish, 36 terrestrial reptiles and 21 amphibians. These include approximately 57% of the terrestrial vertebrates of the biodiversity hotspot of Japan, including 44% of species endemic to Japan as well as 36% of Japan’s globally threatened vertebrates.

Among species listed on IUCN Red List of Threatened Species are the Amami Rabbit, only found on Amami-Oshima and Tokunoshima Islands and the only species in its genus, with no close relatives anywhere in the world, and the flightless Okinawa Rail, endemic to the Northern part of Okinawa Island. Spiny rats form an endemic genus consisting of three species endemic to each of the respective three islands, and the Iriomote Cat, which only inhabits Iriomote Island.

Speciation and endemism are high for many taxa. For example, 188 species of vascular plants and 1,607 insect species are endemic within the four islands of the property. Rates of endemism among terrestrial mammals (62%), terrestrial reptiles (64%), amphibians (86%), and inland water crabs (100%) are also high. Twenty species are identified as Evolutionarily Distinct and Globally Endangered (EDGE) species, including the Okinawa Spiny Rat, Ryukyu Black-Breasted Leaf Turtle, and Kuroiwa’s Ground Gecko.

Integrity

The property is the best representation of the archipelago in which it is located and contains the richest biota in Japan, one of the world’s biodiversity hotspots. The boundaries of the five component parts have been carefully selected to ensure that the entire property is strictly protected and that they capture the key values and demonstrate a generally high degree of connectivity, wherever it is possible to achieve this.  It will be crucial to ensure that buffer zones are actively managed to support the attributes of the property’s OUV and that activities such as logging do not create adverse impacts.

The four islands that host the property consist of mountains and hills with intact and contiguous subtropical rainforests that secure particularly stable habitats for approximately 90% of native species, endemic species and globally threatened species of the central and southern part of the archipelago. There are important naturally functioning freshwater systems, but with some natural values that have been impacted by hard, engineered infrastructure and which could be restored to a more natural function.

The five component parts of the property have intact subtropical forests and other habitats, including many areas of substantial size. These are selected to include the most important current and potential distributional areas of endemic species and threatened species, and are key attributes expressing the Outstanding Universal Value of this property.

Protection and management requirements

The property is under the strictest protection in the Japanese system of nature conservation areas, and its component parts are designated as Special Protection Zones or Class I Special Zones managed by the Ministry of the Environment and/or Preservation Zones of Forest Ecosystem Reserves managed by the Forestry Agency. In addition, the property is designated as a National Wildlife Protection Area and Natural Monument Protection Area. The property thus receives adequate management resources and appropriate long-term protection. Some of the endemic species and/or threatened species of the property, such as the Amami Rabbit, three species of the Spiny Rat, Okinawa Rail and Iriomote Cat, have been designated and legally protected as National Endangered Species and/or National Natural Monuments.

The four islands of the property are inhabited, with residential areas and industrial activities located close to the habitats for endemic and threatened species. Buffer zones are included adjacent to the property, mainly in the Class II Special Zone of a national park and/or the Conservation and Utilization Zone of a Forest Ecosystem Reserve. In addition, Surrounding Conservation Areas encompassing the property and the buffer zones are designated under the Comprehensive Management Plan.

Administrations at all levels, i.e. the Ministry of the Environment, the Forestry Agency, the Agency for Cultural Affairs, Kagoshima and Okinawa Prefectures, and 12 municipalities, have established a Regional Liaison Committee to facilitate and coordinate management of multilayered protected areas and the protection of designated species. They manage the property according to a Comprehensive Management Plan, which covers conservation measures not only in the property but also in the buffer zones and surrounding conservation areas.

Key threats to the property include potential impacts from tourism, posing significant threats to wildlife in some areas, including Iriomote Island. Further threats include impacts from invasive alien species such as the small Indian Mongoose and cats, wildlife roadkill and the illegal collection of wild rare and threatened species. In order to address these threats, the risks to the property are prevented or mitigated by various measures implemented through collaboration among related administrative agencies, private organizations and local communities. In recent years, the tourism industry has increased and sustainable levels of tourism need to be fully assessed and continuously monitored. Invasive alien species and roadkill, especially the potentially critical impact of traffic on endangered species including the Iriomote Cat, need to be kept at an absolute minimum and strictly monitored, and illegal collection of wild rare and threatened species prevented. There is the need to develop a comprehensive river restoration strategy in order to transition wherever possible from hard infrastructure to employ nature-based techniques and rehabilitation approaches.  Activities in the buffer zones, including very limited traditional timber extraction that takes place, also require continued vigilance and to be strictly limited and monitored.

Links

• Nomination of Amami-Oshima Island, Tokunoshima Island, the northern part of Okinawa Island, and Iriomote Island