The Tuamotu tropical moist forests is a

tropical and subtropical moist broadleaf forests Tropical and subtropical moist broadleaf forests (TSMF), also known as tropical moist forest, is a subtropical and tropical forest habitat type defined by the World Wide Fund for Nature (WWF). Description TSMF is generally found in la ...

ecoregion in the

Tuamotu Archipelago The Tuamotu Archipelago or the Tuamotu Islands (, officially ) are a French Polynesian chain of just under 80 islands and atolls in the southern Pacific Ocean. They constitute the largest chain of atolls in the world, extending (from northwest to ...

French Polynesia French Polynesia ( ; ; ) is an overseas collectivity of France and its sole #Governance, overseas country. It comprises 121 geographically dispersed islands and atolls stretching over more than in the Pacific Ocean, South Pacific Ocean. The t ...

and the

Pitcairn Islands The Pitcairn Islands ( ; Pitkern: '), officially Pitcairn, Henderson, Ducie and Oeno Islands, are a group of four volcanic islands in the southern Pacific Ocean that form the sole British Overseas Territories, British Overseas Territory in the ...

Geography

The ecoregion includes the 76 atolls and islands of the

and

Gambier Islands The Gambier Islands ( or ) are an archipelago in French Polynesia, located at the southeast terminus of the Tuamotu archipelago. They cover an area of , and are made up of the Mangareva Islands, a group of high islands remnants of a caldera alo ...

, which stretch 1,800 km from northwest to southeast through

, as well as the

, four islands 1,000 km further southeast which are a self-governing

British overseas territory The British Overseas Territories (BOTs) or alternatively referred to as the United Kingdom Overseas Territories (UKOTs) are the fourteen dependent territory, territories with a constitutional and historical link with the United Kingdom that, ...

. The islands extend from 13º to 25º S latitude and from 124º to 149º W longitude. The Tuamotus are mostly low coral

atoll An atoll () is a ring-shaped island, including a coral rim that encircles a lagoon. There may be coral islands or cays on the rim. Atolls are located in warm tropical or subtropical parts of the oceans and seas where corals can develop. Most ...

s, with the exception of

Makatea Makatea, or Mangaia-te-vai-tamae, is a raised coral atoll in the northwestern part of the Tuamotus, which is a part of the French overseas collectivity of French Polynesia. It is located southwest from Rangiroa to the west of the Palliser Islan ...

, which is made of coralline limestone raised 100 meters above sea level by tectonic activity. The Gambier Islands are mostly high volcanic islands, with

Mangareva Mangareva is the central and largest island of the Gambier Islands in French Polynesia. It is surrounded by smaller islands: Taravai in the southwest, Aukena and Akamaru in the southeast, and islands in the north. Mangareva has a permanent p ...

reaching 435 meters elevation. Karta FP Tuamotus isl

Pitcairn Island is a volcanic island that reaches 350 meters elevation. Henderson is a raised limestone plateau. The other Pitcairn Islands, Ducie and Oeno, are atolls.

Climate

The climate ranges from tropical in the northern Tuamotus, with a mean annual temperature of 27 °C to subtropical in the Pitcairn Islands, which have a mean annual temperature of 23 °C. Average annual rainfall is generally between 1,500 and 2,000 mm, with more rainfall on the windward eastern slopes of the high islands from easterly trade winds.

Flora

The natural vegetation of the islands is mostly tropical moist forest. Broadleaf strand forests are the typical vegetation on atolls and the lowlands of the high islands. The shrubs '' Suriana maritima'' or '' Pemphis acidula'' grow in sandy areas near the beach. '' Scaevola'' spp. and ''

Guettarda speciosa ''Guettarda speciosa'', with common names sea randa, or zebra wood, is a species of shrub in the family Rubiaceae found in coastal habitats in tropical areas around the Pacific Ocean, including the coastline of central and northern Queensland an ...

'' grow between the shore shrubs and ''

Tournefortia argentea ''Heliotropium arboreum'' is a species of flowering plant in the borage family, Boraginaceae. It is native to tropical Asia including southern China, Madagascar, northern Australia, and most of the atolls and high islands of Micronesia and Polyn ...

'' forest. The forest grows more diverse inland, and includes '' Pisonia grandis,

Pandanus tectorius ''Pandanus tectorius'' is a species of ''Pandanus'' (screwpine) that is native to Malesia, Papuasia, eastern Australia, and the Pacific Islands. It grows in the coastal lowlands typically near the edge of the ocean. Common names in English inclu ...

, Pipturus argenteus, Sesbania coccinea, Cordia subcordata,

Morinda citrifolia ''Morinda citrifolia'' is a fruit-bearing tree in the coffee family, Rubiaceae, native to Southeast Asia and Australasia, which was spread across the Pacific by Polynesian sailors. The species is now cultivated throughout the tropics and widel ...

'', and ''

Calophyllum inophyllum ''Calophyllum inophyllum'' is a large evergreen plant, commonly called tamanu, oil-nut, mastwood, beach calophyllum or beautyleaf. It is native to the Old World Tropics, from Africa through Asia to Australia and Polynesia. Due to its importance a ...

''. '' Myrsine naiuensis'' is endemic to Niau atoll. The coastal plateaus of uplifted coralline limestone are home to a tall and dense forest of ''Pisonia grandis, Pandanus tectorius, Ficus prolixa, Homalium mouo, Guettarda speciosa'', and, on Makatea, the endemic palm '' Pritchardia vuylstekeana''. The plateau forest on Henderson also includes '' Thespesia populnea, Bidens hendersonensis,

Celtis ''Celtis'' is a genus of about 60–70 species of deciduous trees, commonly known as hackberries or nettle trees, in the hemp family Cannabaceae. It has a cosmopolitan distribution. Description ''Celtis'' species are generally medium-sized tree ...

'' sp., '' Nesoluma st-johnianum'', and '' Geniostoma hendersonense''. The higher-elevation interior forests on Pitcairn are characterized by the trees ''Homalium mouo, Metrosideros collina, Ficus prolixa, Pandanus tectorius'', and ''Thespesia populnea''. Approximately 14 of the vascular plant species on both Henderson and Pitcairn Islands are endemic. Pitcairn has 80 species of native vascular plants, which include two endemic ferns and eight endemic vascular plants. 51 of the native vascular plants are considered threatened. '' Coprosma benefica'' and the endemic fern '' Angiopteris chauliodonta'' have very small populations, and over-harvesting by islanders has caused '' Cyclophyllum barbatum'' and '' Psydrax odoratum'' to dwindle in numbers. The lack of fruit-eating birds on Pitcairn has limited the dispersal of ''C. benfica, P. odoratum'', and '' Xylosma suaveolens'', decreasing these plants' ability to recover from disturbance.BirdLife International (2020) Important Bird Areas factsheet: Pitcairn Island. Downloaded from http://www.birdlife.org on 25/11/2020.

Fauna

The Tuamotus are home to six endemic bird species, and the Pitcairn Islands support five endemic species. The endemic Polynesian pigeon (''Ducula aurorae''), Makatea fruit dove (''Ptilinopus chalcurus'') and Tuamotu reed warbler (''Acrocephalus atypha'') survive in the remaining forests of Makatea. The endemic

Tuamotu sandpiper The Tuamotu sandpiper (''Prosobonia parvirostris'') is an endangered member of the large wader family Scolopacidae, that is endemic to the Tuamotu Islands in French Polynesia. It is sometimes placed in the monotypic genus ''Aechmorhynchus''. A na ...

(''Prosobonia cancellata'') survives on rat-free islands in the archipelago. Other Tuamotu endemics are the atoll fruit dove (''Ptilinopus coralensis''), which is widespread throughout the archipelago, and the Tuamotu kingfisher (''Todiramphus gambieri'') which is limited to Niau. The

Polynesian ground dove The Polynesian ground dove or Society Islands ground dove (''Pampusana erythroptera'') or ''Tutururu'' is a Critically Endangered, critically endangered species of bird in the family Columbidae. Originally Endemism, endemic to the Society Islands ...

(''Alopecoenas erythropterus'') once lived in the

Society Islands The Society Islands ( , officially ; ) are an archipelago in the South Pacific Ocean that includes the major islands of Tahiti, Mo'orea, Moorea, Raiatea, Bora Bora and Huahine. Politically, they are part of French Polynesia, an overseas country ...

and the Tuamotus, but now survives only in the Tuamotus. Endemic bird species on Henderson are the Henderson fruit dove (''Ptilinopus insularis''), Henderson crake (''Zapornia atra''), Henderson lorikeet (''Vini stepheni''), and Henderson reed warbler (''Acrocephalus taiti''). The Pitcairn reed warbler (''Acrocephalus vaughani'') is endemic to Pitcairn. The ecoregion is an important breeding ground for many seabirds, including 22 species that breed in the Tuamotus and 14 species in the Gambier and Pitcairn Islands. Henderson island is the last known breeding ground for the ground-nesting Henderson petrel (''Pterodroma atrata''). Introduced Polynesian rats are the main killer of petrel chicks, and the former breeding colony on Ducie Island was destroyed by introduced rats. The

bristle-thighed curlew The bristle-thighed curlew (''Numenius tahitiensis'') is a medium-sized shorebird that breeds in Alaska and winters on tropical Pacific islands. It is known in Mangareva as ''kivi'' or ''kivikivi'' and in Rakahanga as ''kihi''; it is said to b ...

(''Numenius tahitensis'') winters in the Tuamotus. Pitcairn has 26 species of extant land snails, of which eight are endemic. Three species survive in patches of native vegetation smaller than one hectare. These remnant habitats are vulnerable to invasion by exotic plants, like lantana or rose-apple, which would make them unsuitable for the land snails. Henderson has nine endemic species of land snail and more than 450 arthropod species, including 50 endemics.

Conservation and threats

Polynesian settlers arrived in the Tuamotus about 1300 years ago, likely from the

. Polynesians brought the

coconut palm The coconut tree (''Cocos nucifera'') is a member of the palm tree family (biology), family (Arecaceae) and the only living species of the genus ''Cocos''. The term "coconut" (or the archaic "cocoanut") can refer to the whole coconut palm, ...

(''Cocos nucifera'') and

candlenut tree ''Aleurites moluccanus'', commonly known as candlenut, is a tree in the spurge family Euphorbiaceae. It grows to about tall and produces drupe fruit. First described by Carl Linnaeus in 1753, the species' origin is unclear due to its spread b ...

(''Aleurites moluccanus'') which naturalized on the islands, as well as pigs and the

Polynesian rat The Polynesian rat, Pacific rat or little rat (''Rattus exulans''), or , is the third most widespread species of rat in the world behind the brown rat and black rat. Contrary to its vernacular name, the Polynesian rat originated in Southeast Asi ...

(''Rattus exulans''). By 1000 Polynesians had reached the Pitcairn Islands and further east to

Rapa Nui Easter Island (, ; , ) is an island and special territory of Chile in the southeastern Pacific Ocean, at the southeasternmost point of the Polynesian Triangle in Oceania. The island is renowned for its nearly 1,000 extant monumental statues, ...

. Pitcairn and Henderson were settled by Polynesians, but both islands were abandoned about 500 years ago. European explorers visited the Tuamotus from the 17th century onwards. By the early 19th century the Tuamotus were subject to the Tahitian kingdom, and in the latter half of the century the Tuamotus were colonized by France when it annexed the kingdom. In 1790, nine British mutineers from HMS ''Bounty'' and their Tahitian companions settled on Pitcairn, and with a brief interruption their descendants have lived there since. Europeans introduced the

black rat The black rat (''Rattus rattus''), also known as the roof rat, ship rat, or house rat, is a common long-tailed rodent of the stereotypical rat genus ''Rattus'', in the subfamily Murinae. It likely originated in the Indian subcontinent, but is n ...

(''Rattus rattus''),

brown rat The brown rat (''Rattus norvegicus''), also known as the common rat, street rat, sewer rat, wharf rat, Hanover rat, Norway rat and Norwegian rat, is a widespread species of common rat. One of the largest Muroidea, muroids, it is a brown or grey ...

(''Rattus norvegicus''), house cats, goats, rabbits, and other animals, along with many of exotic plants. The introduced rats have decimated the islands' endemic land birds and sea birds, and many of the introduced plants have been invasive, displacing native plants and the animals that depend on them. Much habitat has been destroyed by conversion to agriculture including coconut plantations, overgrazing, and frequent human-caused fires. Between 1966 and 1996, France conducted 193 nuclear tests on

Moruroa Moruroa (Mururoa, Mururura), also historically known as Aopuni, is an atoll which forms part of the Tuamotu Archipelago in French Polynesia in the southern Pacific Ocean. It is located about southeast of Tahiti. Administratively Moruroa Atoll i ...

and Fangataufa atolls. Native forests survive on much of Makatea, Niau, and the southeastern Tuamotu atolls. In the Gambier Islands, one patch of native forest survives on Mont Mokota on Mangareva. Henderson's forests are relatively intact, although Polynesian rats have decimated native birds.

Protected areas

A 2017 assessment found that 38 km², or 5%, of the ecoregion is in protected areas. Protected areas include: * Commune of Fakarava Biosphere Reserve encompasses seven coral islands and atolls –

Fakarava Fakarava, Havaiki-te-araro, Havai'i or Farea is an atoll in the west of the Tuamotu group in French Polynesia. It is the second largest of the Tuamotu atolls. The nearest land is Toau, a coral atoll which lies to the northwest. The atoll is ro ...

, Aratika, Niau, Kauehi, Raraka, Taiaro, and Toau. A reserve was established on Taiaro in 1972, which became a biosphere UNESCO biosphere reserve in 1977. Six more islands were added to the reserve in 2006. Most are atolls, with low islands of coral sand surrounding a central lagoon. Taiaro completely encloses its hypersaline lagoon, and Niau encloses a brackish lagoon. The reserve preserves atoll and raised limestone coastal forests from 0–6 meters elevation. Niau is home to the sole population of Tuamotu kingfisher. There are 1,575 residents, mostly on Fakarava, and the residents' coconut plantations. Invasive species include '' Stachytarpheta cayennensis'', black rats, and Polynesian rats.Loope, Lloyd L., R. Flint Hughes, and Jean-Yves Meyer (2013) "Plant Invasions in Protected Areas of Tropical Pacific Islands, with Special Reference to Hawaii" in L.C. Foxcroft et al. (eds.), ''Plant Invasions in Protected Areas: Patterns, Problems and Challenges'', Invading Nature - Springer Series in Invasion Ecology 7, Springer Science+Business Media. DOI 10.1007/978-94-007-7750-7_15 * Henderson Island is a

UNESCO The United Nations Educational, Scientific and Cultural Organization (UNESCO ) is a List of specialized agencies of the United Nations, specialized agency of the United Nations (UN) with the aim of promoting world peace and International secur ...

World Heritage Site World Heritage Sites are landmarks and areas with legal protection under an treaty, international treaty administered by UNESCO for having cultural, historical, or scientific significance. The sites are judged to contain "cultural and natural ...

which includes all 3,700 hectares of the island. The world heritage site was create in 1988, and protects relatively intact coastal and raised limestone forest and scrub. Henderson is home to four endemic bird species, along with endemic land snails and arthropods. Polynesian rats, introduced 800 years ago, prey heavily on the chicks of native birds, including the Henderson petrel whose only known breeding ground is on Henderson. A 2011 rodent eradication program dropped poison grain on the island. It was initially successful, reducing the rat population from 800,000 to 60 to 80 individuals, and the Henderson petrel population briefly rebounded. The rats also rebounded, and by 2016 the population was close to pre-eradication levels.Watson, Traci (2016). "80 Rats Exploded Into 100,000 by Avoiding Poison". ''National Geographic'', 19 April 2016. Accessed 26 November 2020

/ref>

References

External links

* {{WWF ecoregion, name=Tuamotu tropical moist forests, id=oc0115
Tuamotu tropical moist forests (DOPA)

Tuamotu tropical moist forests (Encyclopedia of Earth)
Tuamotus Pitcairn Islands Ecoregions of French Polynesia Oceanian ecoregions Tropical and subtropical moist broadleaf forests Endemic Bird Areas