The Yap tropical dry forests is a

tropical and subtropical dry broadleaf forests The tropical and subtropical dry broadleaf forest is a habitat type defined by the World Wide Fund for Nature and is located at tropical and subtropical latitudes. Though these forests occur in climates that are warm year-round, and may receive ...

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 ...

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 ...

. It includes the

Yap Islands Yap ( yap, Waqaab) traditionally refers to an island group located in the Caroline Islands of the western Pacific Ocean, a part of Yap State. The name "Yap" in recent years has come to also refer to the state within the Federated States of Micro ...

and neighboring atolls in the

Federated States of Micronesia The Federated States of Micronesia (; abbreviated FSM) is an island country in Oceania. It consists of four states from west to east, Yap, Chuuk, Pohnpei and Kosraethat are spread across the western Pacific. Together, the states comprise a ...

Geography

The ecoregion covers the

, an island group in the western

Caroline Islands The Caroline Islands (or the Carolines) are a widely scattered archipelago of tiny islands in the western Pacific Ocean, to the north of New Guinea. Politically, they are divided between the Federated States of Micronesia (FSM) in the centra ...

. The islands are east of

Palau Palau,, officially the Republic of Palau and historically ''Belau'', ''Palaos'' or ''Pelew'', is an island country and microstate in the western Pacific. The nation has approximately 340 islands and connects the western chain of the Caro ...

and southeast of the

Mariana 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 group has four central islands, Yap, Gagil-Tomil, and Maap, and Rumung, which are separated by narrow channels. The highest elevation is Mount Taabiywol () on Yap Island. The islands are surrounded by a lagoon and an enclosing barrier reef. It also includes the atolls of

Ulithi Ulithi ( yap, Wulthiy, , or ) is an atoll in the Caroline Islands of the western Pacific Ocean, about east of Yap. Overview Ulithi consists of 40 islets totaling , surrounding a lagoon about long and up to wide—at one of the largest i ...

to the northeast and Ngulu to the southwest.

Climate

The climate is tropical. Average annual temperature is 27º C with little seasonal variation. Average annual rainfall ranges from 2,250 to 3,400 mm, and is highly seasonal, with a distinct dry season from January through March and heavy rains from May through November. The islands are subject to typhoons.

Flora

Prior to human habitation, the natural vegetation likely consisted mostly of deciduous broadleaf forests. Humans have altered the islands' vegetation, and converted the lowland forests to farms, plantations, and tree gardens. The remaining natural vegetation consists of upland forests, upland savanna, freshwater swamps, and mangroves. The upland forests are mostly secondary forests of low stature, with no stratification. The canopy layer has a diverse mix of tree species including ''

Celtis ''Celtis'' is a genus of about 60–70 species of deciduous trees, commonly known as hackberries or nettle trees, widespread in warm temperate regions of the Northern Hemisphere. The genus is part of the extended hemp family (Cannabaceae). De ...

'' sp., ''

Buchanania engleriana ''Buchanania'' is a genus of plants in the family Anacardiaceae and subfamily Anacardioideae. Species The following are included: *'' Buchanania amboinensis'' Miq. — native to Papua New Guinea *'' Buchanania axillaris'' (Desr.) Ramamoo ...

Campnosperma brevipetiolata ''Campnosperma'' is a genus of rainforest trees in the Cashew Family (Anacardiaceae). They are found in the East Indies, south Asia and the Seychelles. Species , the ''Plants of the World Online'' accepts 14 species: * '' Campnosperma auriculatu ...

, Trichospermum ikutai, Garcinia rumiyo, Pentaphalangium volkensii,

Terminalia catappa ''Terminalia catappa'' is a large tropical tree in the leadwood tree family, Combretaceae, native to Asia, Australia, the Pacific, Madagascar and Seychelles. Common names in English include country almond, Indian almond, Malabar almond, sea almon ...

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 ...

Pangium edule ''Pangium'' is a genus containing the sole species ''Pangium edule'', a tall tree native to the mangrove swamps of Southeast Asia (Indonesia and Papua New Guinea). It produces a large poisonous fruit (the "football fruit" or pangi) which can ...

Aidia cochinchinensis ''Aidia cochinchinensis'' is the type species of ''Aidia'': a plant in the family Rubiaceae; no subspecies are listed in the Catalogue of Life. In the Marshall Islands The Marshall Islands ( mh, Ṃajeḷ), officially the Republic of the Mar ...

'', and ''

Eurya japonica ''Eurya japonica'', known as East Asian eurya, is a 1–3.5 m tall shrub in the Pentaphylacaceae family found in eastern China, Korea, and Japan. It is used as an ornamental plant. In shinto Shinto () is a religion from Japan. Classified as ...

''. The understory shrub layer includes species of ''

Psychotria ''Psychotria'' is a genus of flowering plants in the family Rubiaceae. It contains 1,582 species and is therefore one of the largest genera of flowering plants. The genus has a pantropical distribution and members of the genus are small understor ...

Crateva ''Crateva'' is a genus of flowering plants in the caper family, Capparaceae. Species Accepted species include: * ''Crateva adansonii'' DC. * ''Crateva excelsa'' Bojer * ''Crateva greveana'' Baill. * '' Crateva humblotii'' (Baill.) Hadj-Moust. ...

, Streblus,

Glochidion ''Glochidion'' is a genus of flowering plants, of the family Phyllanthaceae, known as cheese trees or buttonwood in Australia, and leafflower trees in the scientific literature. It comprises about 300 species, distributed from Madagascar to the P ...

Leea ''Leea'' (Tagalog: ''Talyantan'') is a genus of plants that are distributed throughout Northern and eastern Australia, New Guinea, South and Southeast Asia and parts of Africa. The APG IV system places ''Leea'' in the subfamily Leeoideae (Vitacea ...

Hibiscus ''Hibiscus'' is a genus of flowering plants in the mallow family, Malvaceae. The genus is quite large, comprising several hundred species that are native to warm temperate, subtropical and tropical regions throughout the world. Member species ...

Polyscias ''Polyscias'' is a genus of flowering plants in the family Araliaceae. They bear pinnately compound leaves. In 2003, a checklist and nomenclator was published for Araliaceae.David G. Frodin and Rafaël Govaerts. 2003. ''World Checklist and Bibli ...

'', and ''

Ixora ''Ixora'' is a genus of flowering plants in the family Rubiaceae. It is the only genus in the tribe Ixoreae. It consists of tropical evergreen trees and shrubs and holds around 544 species. Though native to the tropical and subtropical areas ...

''. The upland forest is denser and forms a closed canopy in better-watered areas and on deeper soils, and is much more open on exposed or rocky slopes. These secondary forests include a mix of native and cultivated species. The ecoregion's endemic species are mostly from genera also found on Palau, and include ''

Drypetes yapensis ''Drypetes'' is a plant genus of the family Putranjivaceae, in the order Malpighiales. It was previously in the family Euphorbiaceae, tribe Drypeteae, and was the sole pantropical zoochorous genus of the family. The genus comprises about 200 ...

, Drypetes carolinensis, Trichospermum ikutai,

Hedyotis fruticosa ''Hedyotis'' (starviolet) is a genus of flowering plants in the family Rubiaceae. Many species of this genus such as ''Hedyotis biflora, H. corymbosa'' and ''H. diffusa'' are well known medicinal plants. ''Hedyotis'' is native to tropical and sub ...

, Timonius albus'', and '' Casearia cauliflora''. The shrub ''

Myrtella bennigseniana ''Myrtella'' is a genus of plants in the Myrtaceae described as a genus in 1877. It is native to New Guinea and to some islands of the western Pacific.Govaerts, R., Sobral, N., Ashton, P., Barrie, F., Holst, B.K., Landrum, L.L., Matsumoto, K., F ...

'' is found only in savannas on Yap and

Guam Guam (; ch, Guåhan ) is an organized, unincorporated territory of the United States in the Micronesia subregion of the western Pacific Ocean. It is the westernmost point and territory of the United States (reckoned from the geographic cent ...

Fauna

Yap is home to four endemic bird species, the

Yap monarch The Yap monarch (''Monarcha godeffroyi''), or Yap Island monarch, is a species of bird in the family Monarchidae. It is endemic to the Yap Main Islands, Micronesia. Some authorities consider the Yap monarch to belong to the genus '' Metabolus'' ...

(''Monarcha godeffroyi''),

Yap olive white-eye The olive-colored white-eye (''Zosterops oleagineus''), also known as the olive white-eye, Yap olive white-eye or great Yap white-eye, is a species of bird in the family Zosteropidae. Distribution and habitat It is endemic to the Micronesian isl ...

(''Zosterops oleagineus'') plain white-eye (''Zosterops hypolais''), and Yap cicadabird (''Edolisoma nesiotis''). The Yap cicadabird is sometimes considered a subspecies of the common cicadabird (''Edolisoma tenuirostre''). Limited-range species include the

white-throated ground dove The white-throated ground dove (''Pampusana xanthonura'') is a species of ground dove in the genus ''Gallicolumba''. It is classified as near-threatened. This species was formerly in the genus ''Alopecoenas'' Sharpe, 1899, but the name of the ...

(''Alopecoenas xanthonurus''),

Micronesian imperial pigeon The Micronesian imperial pigeon (''Ducula oceanica''), also known as the Micronesian pigeon, and Belochel is a species of bird in the family Columbidae (doves). It is found in Palau, the Caroline Islands, the Marshall Islands and Nauru. Its habit ...

(''Ducula oceanica''),

Micronesian myzomela The Micronesian myzomela (''Myzomela rubratra'') is a species of bird in the honeyeater family Meliphagidae. The species forms a superspecies with a number of related and similar looking island and mainland myzomelas across the Pacific and Austra ...

(''Myzomela rubratra''), and

Micronesian starling The Micronesian starling (''Aplonis opaca'') is a species of starling in the family Sturnidae. It is found in Micronesia, the Northern Mariana Islands, and Palau. Its natural habitats are subtropical or tropical dry forest and subtropical or tro ...

(''Aplonis opaca'').BirdLife International (2020) Endemic Bird Areas factsheet: Yap Islands. Downloaded from http://www.birdlife.org on 29/11/2020. A race of the Indo-Pacific common moorhen (''Gallinula chloropus orientalis'') is found on the islands. The

Yap flying fox The Pelew flying fox (''Pteropus pelewensis'') is a species of megabat in the genus ''Pteropus'' found in the Palau Islands. A subspecies found on Yap, the Yap flying fox, is considered as a separate species by some authorities.D.E. Wilson & D.M. ...

is endemic to the islands; it considered a subspecies of the Palau flying fox (''Pteropus pelewensis yapensis'') or a separate species (''Pteropus yapensis''). A subspecies of the Mariana flying fox (''Pteropus mariannus ulthiensis'') is endemic to Ulithi.

Conservation and threats

The islanders practice a traditional form of

Agroforestry Agroforestry is a land use management system in which trees or shrubs are grown around or among crops or pastureland. Trees produce a wide range of useful and marketable products from fruits/nuts, medicines, wood products, etc. This intentional ...

in tree gardens. These managed forests are composed of a mix of species, mostly introduced, which includes

coconut palm The coconut tree (''Cocos nucifera'') is a member of the palm tree 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, the seed, or the f ...

(''Cocos nucifera''), breadfruit, betel nut, papaya, banana, cassava, two types of taro, and a variety of medicinal and ornamental plants. The native plants and animals suffer from habitat loss. The introduced

Polynesian rat The Polynesian rat, Pacific rat or little rat (''Rattus exulans''), known to the Māori as ''kiore'', is the third most widespread species of rat in the world behind the brown rat and black rat. The Polynesian rat originated in Southeast Asia, a ...

(''Rattus exulans'') and

brown tree snake The brown tree snake (''Boiga irregularis''), also known as the brown catsnake, is an arboreal rear-fanged colubrid snake native to eastern and northern coastal Australia, eastern Indonesia (Sulawesi to Papua), Papua New Guinea, and many islands ...

(''Boiga irregularis'') prey heavily on native birds.

Protected areas

There are no formal protected areas on Yap. Land is privately owned or managed communally, with exploitation of natural resources regulated through customary management.

References

External links

*{{WWF ecoregion, name=Yap tropical dry forests, id=oc0204
Yap tropical dry forests (DOPA)

Yap tropical moist forests (Encyclopedia of Earth)
Caroline Islands Environment of the Federated States of Micronesia Geography of the Federated States of Micronesia Oceanian ecoregions Tropical and subtropical moist broadleaf forests