Ogasawara subtropical moist forests
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The Ogasawara subtropical moist forests is a terrestrial
ecoregion An ecoregion (ecological region) or ecozone (ecological zone) is an ecologically and geographically defined area that is smaller than a bioregion, which in turn is smaller than a biogeographic realm. Ecoregions cover relatively large areas of ...
which encompasses the Ogasawara Archipelago of Japan. The Ogasawara Archipelago lies in the Pacific Ocean south of
Honshu , historically called , is the largest and most populous island of Japan. It is located south of Hokkaidō across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyūshū across the Kanmon Straits. The island se ...
, Japan's largest island, and north of the
Marianas Islands The Mariana Islands (; also the Marianas; in Chamorro: ''Manislan Mariånas'') are a crescent-shaped archipelago comprising the summits of fifteen longitudinally oriented, mostly dormant volcanic mountains in the northwestern Pacific Ocean, betw ...
. The ecoregion includes the
Bonin Islands The Bonin Islands, also known as the , are an archipelago of over 30 subtropical and tropical islands, some directly south of Tokyo, Japan and northwest of Guam. The name "Bonin Islands" comes from the Japanese word ''bunin'' (an archaic read ...
and
Volcano Islands The or are a group of three Japanese-governed islands in Micronesia. They lie south of the Ogasawara Islands and belong to the municipality of Ogasawara, Tokyo, Tokyo Metropolis, Japan. The islands are all active volcanoes lying atop ...
chains. The islands are volcanic in origin, and have never been linked to a continent. They are home to distinct plants and animals including many
endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...
species. The islands also constitute a distinct
freshwater ecoregion An ecoregion (ecological region) or ecozone (ecological zone) is an ecologically and geographically defined area that is smaller than a bioregion, which in turn is smaller than a biogeographic realm. Ecoregions cover relatively large areas of l ...
(Ogasarawa Islands - Kazan Archipelago).


Geography

The Bonin Islands are about 1000 km south of
Honshu , historically called , is the largest and most populous island of Japan. It is located south of Hokkaidō across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyūshū across the Kanmon Straits. The island se ...
, Japan's largest island, and north of the
Tropic of Cancer The Tropic of Cancer, which is also referred to as the Northern Tropic, is the most northerly circle of latitude on Earth at which the Sun can be directly overhead. This occurs on the June solstice, when the Northern Hemisphere is tilted tow ...
. The Bonin islands form three clusters, Mukojima,
Chichijima , native_name_link = , image_caption = Map of Chichijima, Anijima and Otoutojima , image_size = , pushpin_map = Japan complete , pushpin_label = Chichijima , pushpin_label_position = , pushpin_map_alt = , ...
, and
Hahajima , native_name_link = , image_caption = Map of the Hahajima Rettō (Imōtojima is mislabeled as Tori-shima) , image_size = , pushpin_map = Japan complete , pushpin_label = Hahajima , pushpin_label_position = , pushp ...
, composed of one larger island and several smaller ones. Chichishima, the largest island, and Hahajima, the second-largest, are the only inhabited Bonin islands. The highest point on Hahajima is 326 m, and Chichishima's highest point is 462 m. The Bonin Islands have sea cliffs along the shore. The center of Chichishima and other islands in the group (Ani-shima and Ototo-shima) is rolling plateau, while Hahajima has steep ridges and Mukojima is mostly flat.International Union for Conservation of Nature and UN Environment World Conservation Monitoring Centre (2017) "Ogasawara Islands". World Heritage Datasheet. Accessed 27 July 2020

/ref> The Volcano or Kazan islands lie south of the Bonin Islands. Iwo Jima is the largest of the Volcano Islands. The others are Kita Iwo Jima, Minami Iwo Jima, and Nishinoshima. Iwo Jima and Kita Iwo Jima are inhabited. Nishinoshima is volcanically active. The Bonin and Volcano islands are the central portion of the
Izu–Bonin–Mariana Arc The Izu–Bonin–Mariana (IBM) arc system is a tectonic plate convergent boundary in Micronesia. The IBM arc system extends over 2800 km south from Tokyo, Japan, to beyond Guam, and includes the Izu Islands, the Bonin Islands, and the Marian ...
, an
island arc Island arcs are long chains of active volcanoes with intense seismic activity found along convergent tectonic plate boundaries. Most island arcs originate on oceanic crust and have resulted from the descent of the lithosphere into the mantle alon ...
created by the subduction of the Pacific Plate under the
Philippine Sea Plate The Philippine Sea Plate or the Philippine Plate is a tectonic plate comprising oceanic lithosphere that lies beneath the Philippine Sea, to the east of the Philippines. Most segments of the Philippines, including northern Luzon, are part o ...
that stretches 2800 km.


Flora

Flora has evolved differently on each of the islands. The Ogasawara Islands are sometimes referred to as the Galápagos of the Orient. The endemic palm ''
Clinostigma savoryanum ''Clinostigma savoryanum'', the Pacific beauty palm, arrack tree or noyashi apanese ノヤシ is a species of flowering plant in the family Arecaceae. It is endemic to Ogasawara-shoto (Bonin Islands) of Japan Japan ( ja, 日本, or , a ...
'' is the northernmost species of the palm genus ''
Clinostigma ''Clinostigma'' is a genus of flowering plant in the Arecaceae (palm) family, native to various islands in the western Pacific. It contains the following species:Govaerts, R. & Dransfield, J. (2005). World Checklist of Palms: 1-223. The Board of ...
''. ''
Metrosideros boninensis ''Metrosideros boninensis'' is a species of flowering plant in the family Myrtaceae. It is endemic to the Bonin Islands archipelago An archipelago ( ), sometimes called an island group or island chain, is a chain, cluster, or collection ...
'' is an endemic tree of genus '' Metrosideros'', a common tree in the southern tropical Pacific but generally absent from
Micronesia Micronesia (, ) is a subregion of Oceania, consisting of about 2,000 small islands in the western Pacific Ocean. It has a close shared cultural history with three other island regions: the Philippines to the west, Polynesia to the east, and ...
."Ogasawara subtropical moist forests". ''Encyclopedia of Earth''. Acccessed 28 July 2020

/ref> The islands are home to about 500 plant species, of which 43% are endemic. There are three main types of forest on the islands: *Type I: ''
Elaeocarpus ''Elaeocarpus'' is a genus of nearly five hundred species of flowering plants in the family Elaeocarpaceae native to the Western Indian Ocean, Tropical and Subtropical Asia, and the Pacific. Plants in the genus ''Elaeocarpus'' are trees or shrub ...
-
Ardisia ''Ardisia'' (coralberry or marlberry) is a genus of flowering plants in the family Primulaceae. It was in the former Myrsinaceae family now recognised as the myrsine sub-family Myrsinoideae. They are distributed in the Americas, Asia, Australia, ...
'' is a mesic forest found moist lowland areas with deep soils. The forests have a closed canopy with a height of about , dominated by ''
Ardisia sieboldii ''Ardisia'' (coralberry or marlberry) is a genus of flowering plants in the family Primulaceae. It was in the former Myrsinaceae family now recognised as the myrsine sub-family Myrsinoideae. They are distributed in the Americas, Asia, Australia ...
''. '' Elaeocarpus photiniifolius'', ''
Pisonia umbellifera ''Ceodes umbellifera'', synonym ''Pisonia umbellifera'', commonly known as the birdlime tree or bird catcher tree, is a species of plant in the Nyctaginaceae family. The evergreen shrub has soft wood, small pink or yellow flowers, and produces ca ...
'', and ''
Pouteria obovata ''Pouteria obovata'' is a tree in the family Sapotaceae. Confusingly, this is not the same plant that was formerly known by the same scientific name, the Andean '' Pouteria lucuma''. The common name in Australia is the northern yellow boxwood. It ...
'' are other important canopy species. These forests were almost completely destroyed by clearing for agriculture before 1945. *Type II: '' Distylium-
Rhaphiolepis ''Rhaphiolepis'' ( or ;The first pronunciation is that expected for Anglo-Latin; the second is common in nurseries. ''Sunset Western Garden Book,'' 1995:606–607. However, William T. Stearn in his book ''Botanical Latin'' says "Botanical Latin ...
-
Schima ''Schima'' is a genus of evergreen trees belonging to the tea family, Theaceae. The genus inhabits warm temperate to subtropical climates across southern and southeastern Asia, from the eastern Himalaya of Nepal and eastern India across Ind ...
'' dry forest is found in drier lowland and upland sites with shallower soils. It is also a closed-canopy forest, with a canopy composed mostly of '' Distylium lepidotum'', ''
Rhaphiolepis integerrima ''Rhaphiolepis'' ( or ;The first pronunciation is that expected for Anglo-Latin; the second is common in nurseries. ''Sunset Western Garden Book,'' 1995:606–607. However, William T. Stearn in his book ''Botanical Latin'' says "Botanical Latin ...
'', ''
Schima mertensiana ''Schima'' is a genus of evergreen trees belonging to the tea family, Theaceae. The genus inhabits warm temperate to subtropical climates across southern and southeastern Asia, from the eastern Himalaya of Nepal and eastern India across Indochin ...
'', ''Pouteria obovata'', and '' Syzygium buxifolium''. The Type II forests are of two sub-types: **Type IIa: ''Distylium-Schima'' dry forest occurs in cloudy upland areas with fine-textured soils. ''
Pandanus boninensis ''Pandanus boninensis'' is an Asian species of plant that is endemic to and common in the ''Distylium''-''Schima'' dry forests and ''Raphiolepis''-'' Livistona'' dry forests of the Ogasawara Islands, Japan. It has aerial prop roots and grows on r ...
'' and ''Syzygium buxifolium'' as the predominant trees, and these forests contain many rare and endemic species. **Type IIb: ''Rhaphiolepis-Livistona'' dry forest is found in drier upland areas with rocky soils. ''Rhaphiolepis integerrima'' is the dominant tree species, along with the
fan palm Fan palm as a descriptive term can refer to any of several different kinds of palms (Arecaceae) in various genera with leaves that are palmately lobed (rather than pinnately compound). Most are members of the subfamily Coryphoideae, though a few ...
''
Livistona boninensis ''Livistona boninensis'' is a species of flowering plant in the family Arecaceae (palms), native to the Bonin Islands of Japan. It has been introduced into the Volcano Islands The or are a group of three Japanese-governed islands in ...
'', ''Pandanus boninensis'' and '' Ochrosia nakaiana''. *Type III: ''Distylium-Pouteria'' scrub forest is found on windy and dry mountain ridges and exposed sea cliffs. These forests have the highest species diversity on the islands. '' Distylium lepidotum'' and ''Pouteria obovata'' are the dominant species, growing from tall. Other common shrubs are '' Myrsine okabeana'', ''
Symplocos kawakamii ''Symplocos'' is a genus of flowering plants in the order Ericales. It contains about 300 species distributed in Asia and the Americas. Many species grow in humid tropical regions. This is sometimes considered to be the only genus in family Sympl ...
'', and '' Pittosporum parvifolium''.


Fauna

There are 236 species of birds in the islands."Bonin Islands" ''Avibase - Bird Checklists of the World''. BirdLife International. Accessed 27 July 2020

/ref> The near-threatened
Bonin white-eye The Bonin white-eye (''Apalopteron familiare'') or is a small songbird endemic to the Bonin Islands (Ogasawara Islands) of Japan. It is the only species in the genus ''Apalopteron''. Its taxonomic affinities were a long-standing mystery and it ...
(''Apalopteron familiare''), formerly known as "Bonin honeyeater", is endemic to islands. The
Japanese wood pigeon The Japanese wood pigeon (''Columba janthina'') is a species of columbid bird. It is found in East Asia along shorelines of the Pacific's Korea Strait, Philippine Sea and East China Sea. They are believed to be the largest representative of the ...
(''Columba janthina''), which inhabits the ecoregion along with the
Nansei Islands The , also known as the or the , are a chain of Japanese islands that stretch southwest from Kyushu to Taiwan: the Ōsumi, Tokara, Amami, Okinawa, and Sakishima Islands (further divided into the Miyako and Yaeyama Islands), with Yonagun ...
, was extirpated from the Volcano Islands in the 1980s. Matsudaira's storm-petrel (''Oceanodroma matsudairae'') and
Bryan's shearwater Bryan's shearwater (''Puffinus bryani'') is a species of shearwater that may occur around the Hawaiian Islands. It is the smallest species of shearwater and is black and white with a bluish gray beak and blue tarsi. First collected in 1963 and t ...
(''Puffinus bryani'') are breeding endemics. The
Bonin petrel The Bonin petrel or'' nunulu'' (''Pterodroma hypoleuca'') is a seabird in the family Procellariidae. It is a small gadfly petrel that is found in the northwest Pacific Ocean. Its secretive habits, remote breeding colonies and limited range have re ...
(''Pterodroma hypoleuca'') ranges across the islands in the northern Pacific region from the East China Sea to Hawaii, but breeds only in the Ogasawara Islands and the western Hawaiian Islands. The Bonin pigeon (''Columba versicolor'') and
Bonin thrush The Bonin thrush (''Zoothera terrestris''), also known as Kittlitz's thrush or the Bonin Islands thrush, is an extinct species of Asian thrush. It is sometimes separated as the only species of the genus ''Cichlopasser''. The only place where th ...
(''Zoothera terrestris'') are extinct. A small bat, Sturdee's pipistrelle, is only known in one record and has not been seen since 1915. The
Bonin flying fox The Bonin flying fox, Bonin fruit bat (''Pteropus pselaphon''), or in Japanese is a species of flying fox in the family Pteropodidae. It is endemic to four islands (Chichijima, Hahajima, North Iwo Jima, and South Iwo Jima) in Ogasawara Islands ...
(''Pteropus pselaphon''), also called the Bonin fruit bat, is endemic to the islands. It is currently listed as
Endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and in ...
, and a survey published by the Ogasawara Office of Education in 1999 estimated their number to be around 100. There are two terrestrial reptiles on the islands, the endemic Ogasawara snake-eyed skink (''Cryptoblepharus nigropunctatus'') and Micronesian gecko (''Perochirus ateles''). The islands have 134 species of land snails, including 100 endemic species. Land snails on several islands have been decimated by the introduced New Guinea flatworm (''Platydemus manokwari'').


Freshwater

The islands are home to 40 species of freshwater fish, including an endemic
goby Goby is a common name for many species of small to medium sized ray-finned fish, normally with large heads and tapered bodies, which are found in marine, brackish and freshwater environments. Traditionally most of the species called gobies have b ...
, '' Rhinogobius ogasawaraensis''. There are two endemic species of
caddisflies The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which can be divided into the suborders Integripalpia and Annulipalpia on the ...
(Trichoptera). '' Goera ogasawaraensis'' inhabits headwater streams on Chichijima, and '' Hydroptila ogasawaraensis'' is found in streams on Chichijima and Hahajima. The islands have nine species of freshwater and brackish-water shrimps – three of the family
Palaemonidae Palaemonidae is a family of shrimp in the order Decapoda. Many species are carnivores that eat small invertebrates, and can be found in any aquatic habitat except the deep sea. One significant genus is ''Macrobrachium'', which contains commercia ...
, five of the family
Atyidae Atyidae is a family of shrimp, present in all tropical and most temperate waters of the world. Adults of this family are almost always confined to fresh water. This is the only family in the superfamily Atyoidea. Genera and species The followin ...
, and one of genus '' Metabetaeus''. The brackish-water shrimp '' Palaemon ogasawaraensis'' from Chichijima is endemic, as is '' Paratya boninensis'', a freshwater shrimp found in headwater streams on Chichijima and Hahajima. There are endemic species of
mitten crab The Chinese mitten crab ('; ,  "big sluice crab"), also known as the Shanghai hairy crab (, p ''Shànghǎi máoxiè''), is a medium-sized burrowing crab that is named for its furry claws, which resemble mittens. It is native to river ...
(''
Eriocheir ogasawaraensis ''Eriocheir'' is a genus of crabs, including the Chinese mitten crab, ''E. sinensis''. Formerly in the family Grapsidae, it is now placed in the Varunidae The Varunidae are a family of thoracotrematan crabs. The delimitation of this family, p ...
''), sesarmid crab ('' Chiromantes magnus''), and
fiddler crab The fiddler crab or calling crab may be any of more than one hundred species of semiterrestrial marine crabs in the family Ocypodidae, well known for their sexually dimorphic claws; the males' major claw is much larger than the minor claw, while ...
('' Uca boninensis''), and the freshwater snail '' Stenomelania boninensis''.Satake, Kiyoshi, Ryuhei Ueno, and Tetsuro Sasaki (2019). "Freshwater and Brackish-water Macroinvertebrates in the Ogasawara Islands". ''Global Environmental Research'' 23/2019: 073-075.


Protected areas

A 2017 assessment found that 73 km², or 73%, of the ecoregion is in protected areas.
Ogasawara National Park is a national park in the Ogasawara Islands, located approximately one thousand kilometres to the south of Tokyo, Japan. The park was established in 1972 within the Municipalities of Japan, municipality of Ogasawara, Tokyo, Ogasawara, itself pa ...
, established in 1972, is the largest protected area. In 2011, the Ogasawara Islands were designated a
UNESCO The United Nations Educational, Scientific and Cultural Organization is a specialized agency of the United Nations (UN) aimed at promoting world peace and security through international cooperation in education, arts, sciences and culture. It ...
World Heritage Site A World Heritage Site is a landmark or area with legal protection by an international convention administered by the United Nations Educational, Scientific and Cultural Organization (UNESCO). World Heritage Sites are designated by UNESCO for h ...
.


External links


References

{{reflist Bonin Islands Volcano Islands Ecoregions of Japan Ecoregions of Asia 01 . Forests of Japan Freshwater ecoregions Oceanian ecoregions Tropical and subtropical moist broadleaf forests