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
Marquesas Islands
The Marquesas Islands ( ; or ' or ' ; Marquesan language, Marquesan: ' (North Marquesan language, North Marquesan) and ' (South Marquesan language, South Marquesan), both meaning "the land of men") are a group of volcano, volcanic islands in ...
of
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 ...
.
Geography
The Marquesas Islands include 12 major islands of volcanic origin. They extend northwest to southeast between 8º and 11º S latitude and 139º and 141º W longitude. The islands are part of
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 ...
, lying north of the
Tuamotu
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 ...
islands, south of Hawaii, and approximately west of South America.
The islands are volcanic in origin, created by the slow west-northwest movement of the Pacific Plate over the Marquesas hotspot. The northwestern islands are approximately 6 million years old, and the southeast islands are younger at 1.3 million years old.
The islands are composed of basalt rock, and have mountainous terrain with sharp ridges, deep canyons, and steep cliffs. The largest and highest islands are:
* Nuku Hiva – ,
* Hiva Oa – ,
* Ua Pou – ,
* Fatu Hiva – ,
*
Ua Huka
Ua Huka is one of the Marquesas Islands, in French Polynesia, an overseas territory of France in the Pacific Ocean. It is situated in the northern group of the archipelago, approximately to the east of Nuku Hiva, at .
Name
Ua Huka in Marquesan ...
The islands have a tropical climate. Average annual rainfall varies with elevation and orientation, from 500 mm on leeward lowlands to 4000 mm or more on windward slopes above 1000 meters on the five highest islands. Trade winds blow from the southeast during most of the year, and the windward eastern slopes tend to be wetter than the leeward western slopes. The east-facing mountain slopes are cooler, with mean temperatures of 15º to 25 °C, while the hottest mean temperatures (25º to 29 °C) are in the dry western lowlands.
Flora
The natural vegetation is principally tropical moist forest, which varies in height and
species composition
Relative species abundance is a component of biodiversity and is a measure of how common or rare a species is relative to other species in a defined location or community.Hubbell, S. P. 2001. ''The unified neutral theory of biodiversity and biogeog ...
with rainfall and elevation.
Lowland forests extend up to about 300 m with areas of up to 2000 mm of annual rainfall. Typical lowland forests are dominated by '' Pisonia grandis'', which forms a canopy up to 15 meters high, along with the trees '' Thespesia populnea,
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 ...
'', and '' Terminalia glabrata''. Tropical dry forest occurred on drier leeward slopes of the larger islands, characterized by species of ''
Hibiscus
''Hibiscus'' is a genus of flowering plants in the Malva, mallow family, Malvaceae. The genus is quite large, comprising List of Hibiscus species, several hundred species that are Native plant, native to warm temperate, Subtropics, subtropical ...
,
Pandanus
''Pandanus'' is a genus of monocots with about 578 accepted species. They are palm-like, dioecious trees and shrubs native to the Old World tropics and subtropics. Common names include pandan, screw palm and screw pine. The genus is classified ...
,
Thespesia
''Thespesia'' is a genus of 14 flowering shrubs and trees in the ''Hibiscus'' family, Malvaceae, although within the family they are more closely related to cotton plants (''Gossypium''). The genus is distributed from the South Pacific through A ...
'', and '' Cordia''. Native lowland forests have mostly been replaced with introduced trees. Archeological evidence shows that some pre-settlement lowland forest trees are now extinct, including species of '' Planchonella'' and cf. '' Sideroxylon'' (Sapotaceae), and a species of ''
Allophylus
''Allophylus'' is a genus within the plant family Sapindaceae
The Sapindaceae are a family (biology), family of flowering plants in the order Sapindales known as the soapberry family. It contains 138 genera and 1,858 accepted species. Example ...
'' (
Sapindaceae
The Sapindaceae are a family (biology), family of flowering plants in the order Sapindales known as the soapberry family. It contains 138 genera and 1,858 accepted species. Examples include Aesculus, horse chestnut, maples, ackee and lychee.
The ...
) extirpated from Nuku Hiva.
Mid-elevation forests occur between 300 and 800 meters elevation, with annual rainfall of 2,000 to 3,000 mm. Typical trees include '' Hibiscus tiliaceus,
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 ...
Angiopteris evecta
''Angiopteris evecta'', commonly known as the king fern, giant fern, elephant fern, oriental vessel fern, Madagascar tree fern, or mule's foot fern, is a very large rainforest fern in the family Marattiaceae native to most parts of Southeast Asia ...
Cyathea affinis
''Cyathea affinis'' is a variable species of tree fern native to Fiji, Samoa, the Cook Islands, Austral Islands, Tahiti, and the Marquesas Islands. The trunk of this plant is erect and 2–6 m tall. Fronds are bipinnate and 2–3 m in length. ...
'' and '' Sphaeropteris feani'' predominate in wet areas, and '' Metrosideros collina'' and ''Pterophylla marquesana'' on drier slopes. A cloud forest belt occurs above 1000 meters elevation, with a low-canopied forest of '' Cheirodendron bastardianum, Ilex anomala'', and ''Metrosideros collina'', with climbers of '' Freycinetia'' spp.
Mountaintops above 1,200 m are drier and windswept, supporting a heathland of low trees and shrubs up to one meter high, including ''M. collina, Vaccinium cereum, Styphelia tameiameiae'', and '' Bidens'' spp., interspersed with grasses and ferns.
42% of the 320 native vascular plant species are endemic.
Fauna
The ancestors of the Marquesas' native fauna arrived via long-distance dispersal from other islands, and evolved into distinct forms over millions of years.
The ecoregion has 19 breeding seabird species and 11 resident land birds, including ten endemic bird species.
Endemic species include the Marquesas ground dove (''Gallicolumba rubescens''), Marquesas kingfisher (''Halcyon godeffroyi''), Fatuhiva monarch (''Pomarea whitneyi''), Iphis monarch (''P. iphis''), and Marquesas monarch (''P. mendozae''). Most endemic species have been decimated by introduced rats, which prey on eggs and chicks. The Nuku Hiva pigeon (''Ducula galeata'') is now limited to a few hundred individuals on Nuku Hiva. The ultramarine lory (''Vini ultramarina'') once ranged across the archipelago, but predation by introduced black rats reduced its range to Ua Huka island. The birds were reintroduced on Fatu Hiva in conjunction with a rat control program. The red-moustached fruit dove (''Ptilinopus mercierii'') is now extinct.
The Marquesas are home to at least 78 species of land and freshwater snails.
There are 1198 species of terrestrial
arthropod
Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an arthropod exoskeleton, exoskeleton with a cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate, a body with differentiated (Metam ...
s in the Marquesas, 681 (53%) of which are considered endemic to the islands, 138 (11.5%) are introduced, and the remainder mostly native with some of uncertain status. The majority of the endemic insect species are contained in five orders:
Coleoptera
Beetles are insects that form the Taxonomic rank, order Coleoptera (), in the superorder Holometabola. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 40 ...
(beetles),
Diptera
Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advance ...
(flies),
Hemiptera
Hemiptera (; ) is an order of insects, commonly called true bugs, comprising more than 80,000 species within groups such as the cicadas, aphids, planthoppers, leafhoppers, assassin bugs, bed bugs, and shield bugs. They range in size from ...
(true bugs),
Hymenoptera
Hymenoptera is a large order of insects, comprising the sawflies, wasps, bees, and ants. Over 150,000 living species of Hymenoptera have been described, in addition to over 2,000 extinct ones. Many of the species are parasitic.
Females typi ...
(wasps, bees and ants), and
Lepidoptera
Lepidoptera ( ) or lepidopterans is an order (biology), order of winged insects which includes butterflies and moths. About 180,000 species of the Lepidoptera have been described, representing 10% of the total described species of living organ ...
(butterflies and moths). Many of the endemic species are native to a single island. Insect genera which have significant radiations of endemic species in the Marquesas include '' Asymphorodes'' (Lepidoptera, 21 spp.), '' Prochaetops'' (Diptera, 15 spp., possibly not all endemic), '' Campsicnemus'' (Diptera, 15 spp.), '' Pacificola'' (Coleoptera, 13 spp.), '' Dichelopa'' (Lepidoptera, 13 spp.), '' Sierola'' (Hymenoptera, 12 spp.), and '' Campylomma'' (Hemiptera, 11 spp.).
Human impacts
Humans have altered landscape and flora and fauna of the islands since the arrival of Polynesians in the 11th and 12th centuries. Polynesian settlers introduced 33 to 37 species of plants to the islands, Including 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''),
breadfruit
Breadfruit (''Artocarpus altilis'') is a species of flowering tree in the mulberry and jackfruit family ( Moraceae) believed to have been selectively bred in Polynesia from the breadnut ('' Artocarpus camansi''). Breadfruit was spread into ...
paper mulberry
The paper mulberry (''Broussonetia papyrifera'', syn. ''Morus papyrifera'' L.) is a species of flowering plant in the family Moraceae. It is native to Asia,Schizostachyum glaucifolium''), some of which have naturalized across the archipelago, 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''). Much of the native lowland forest vegetation was replaced with traditional
agroforestry
Agroforestry (also known as agro-sylviculture or forest farming) is a land use management system that integrates trees with crops or pasture. It combines agricultural and forestry technologies. As a polyculture system, an agroforestry system c ...
systems centered on the introduced breadfruit and coconut. These agroforestry landscapes provide food, fiber, and building materials while largely preventing soil erosion and nutrient depletion.
Europeans started visiting the islands in the 18th century and later conquered and settled there. Europeans brought with them many more exotic plants and animals, including
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 ...
s (''Rattus rattus'') which have decimated the islands' birds. Introduced sheep and goats have denuded some areas of vegetation, particularly in drier parts of the islands. Introduced grasses, shrubs, and trees are often fast-growing and adapted to grazing and fire, and can outcompete native species. By the 19th century commercial coconut plantations occupied much of the lowlands.
Relatively intact natural vegetation covers about 43% of the ecoregion's area. Most of the lowlands are used for agriculture and pasture, and very little natural lowland forest remains.
Protected areas
A 2017 assessment found that 37 km2, or 7%, of the ecoregion is in protected areas.