The New Guinea mangroves is a

mangrove A mangrove is a shrub or tree that grows in coastal saline water, saline or brackish water. The term is also used for tropical coastal vegetation consisting of such species. Mangroves are taxonomically diverse, as a result of convergent evoluti ...

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 ...

that covers extensive areas of the coastline

New Guinea New Guinea (; Hiri Motu Hiri Motu, also known as Police Motu, Pidgin Motu, or just Hiri, is a language of Papua New Guinea, which is spoken in surrounding areas of Port Moresby (Capital of Papua New Guinea). It is a simplified version of ...

, the large island in the western

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

north of

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

Location and description

The New Guinea mangroves cover an area of , particularly among the river mouths of the island's south coast. This ecoregion contains the greatest diversity of mangrove species in the world and they are an important habitat for wildlife. Areas of mangroves on the northern coast of New Guinea can be found at the mouths of the

Sepik The Sepik () is the longest river on the island of New Guinea, and the second largest in Oceania by discharge volume after the Fly River. The majority of the river flows through the Papua New Guinea (PNG) provinces of Sandaun (formerly West Se ...

and

Ramu The Ramu River is a major river in northern Papua New Guinea. The headwaters of the river are formed in the Kratke Range from where it then travels about northwest to the Bismarck Sea. Along the Ramu's course, it receives numerous tributaries ...

rivers on the eastern side of

Cenderawasih Bay Cenderawasih Bay ( id, Teluk Cenderawasih, "Bird of Paradise Bay"), also known as Sarera Bay ( id, Teluk Sarera) and formerly Geelvink Bay ( nl, Geelvinkbaai), is a large bay in northern Province of Papua, Central Papua and West Papua, New Guine ...

, and

Dyke Ackland Bay Dyke Ackland Bay is a large bay in the Oro Province of Papua New Guinea. The bay extends from Cape Nelson to Cape Ward Hunt. Porlock Bay and Oro Bay are some of the smaller bays located within the larger bay. The bay was named by Captain John More ...

and

Ward Hunt Strait The Ward Hunt Strait is a 30 km wide stretch of water in Milne Bay, separating Papua New Guinea from Goodenough Island in the D'Entrecasteaux Islands. The Dart Reefs and Keast Reef are located in the centre of the channel.Purari,

Kikori Kikori is a small town in the Gulf Province of Papua New Guinea. Kikori lies in the delta of the Kikori River at the head of the Gulf of Papua. This area is particularly biologically rich with a diversity of ecosystems and densely forested, wit ...

Fly Flies are insects of the Order (biology), order Diptera, the name being derived from the Ancient Greek, Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwing ...

s as well as

Bintuni Bay Bintuni Bay ( id, Teluk Bintuni) is the eastward extension or inner bay of Berau Gulf off Bird's Head Peninsula of New Guinea New Guinea (; Hiri Motu: ''Niu Gini''; id, Papua, or , historically ) is the world's second-largest island wi ...

and other areas of the southern

Bird's Head Peninsula The Bird's Head Peninsula ( Indonesian: ''Kepala Burung'', nl, Vogelkop) or Doberai Peninsula (''Semenanjung Doberai''), is a large peninsula that makes up the northwest portion of the island of New Guinea, comprising the Indonesian provinces o ...

. Some areas such as the Kikori delta have larger and thicker mangroves than others.

Climate

The coast of New Guinea has a

Tropical monsoon climate An area of tropical monsoon climate (occasionally known as a sub-equatorial, tropical wet climate or a tropical monsoon and trade-wind littoral climate) is a tropical climate sub-type that corresponds to the Köppen climate classification category ...

apart from the length of drier

Trans-Fly savanna and grasslands The Trans Fly savanna and grasslands are a lowland ecoregion on the south coast of the island of New Guinea in both the Indonesian and Papua New Guinean sides of the island. With their monsoon and dry season climate these grasslands are quite di ...

coastline on the south coast.

The growth of mangroves

Mangroves depend on a complex series of dynamic natural tidal processes that create the conditions for their survival. Rivers depositing sediment, together with waves and coastal currents, reshape the tidal zone where mangroves thrive. There are several features that all species of mangroves have in common. These include tolerance to conditions of high

soil salinity Soil salinity is the salt content in the soil; the process of increasing the salt content is known as salinization. Salts occur naturally within soils and water. Salination can be caused by natural processes such as mineral weathering or by the ...

, tolerance to submergence in water, or waterlogged soil, and to low

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...

conditions. The use of water to disperse young plants is also very characteristic of mangroves. As a result of the water-logged soil that mangrove trees reside in, they have formed adaptations to help them survive. For example, black mangroves survive in water-logged soil by using special "root snorkels" called

pneumatophores Aerial roots are roots above the ground. They are almost always adventitious. They are found in diverse plant species, including epiphytes such as orchids (''Orchidaceae''), tropical coastal swamp trees such as mangroves, banyan figs (''Fic ...

. These structures are covered with small holes call

lenticel A lenticel is a porous tissue consisting of cells with large intercellular spaces in the periderm of the secondarily thickened organs and the bark of woody stems and roots of dicotyledonous flowering plants. It functions as a pore, providing a ...

s that allow the roots to breathe the same way a snorkel lets you breathe while underwater. When trying to overcome the obstacle of the salinity that these trees live in, they have a few adaptations. They can actually concentrate much of the salt concentration in older leaves, which are soon to fall off, taking the excess salt with them. Some species even have salt glands which excrete salt to the surface of the leaves allowing it to be washed away by rain. Mangroves begin as a seed called a

propagule In biology, a propagule is any material that functions in propagating an organism to the next stage in its life cycle, such as by dispersal. The propagule is usually distinct in form from the parent organism. Propagules are produced by organisms ...

, which germinates while still attached to the tree. The seed has a long cylindrical shape that falls off the parent tree and either sticks in the mud growing next to the parent tree, or floats off to sea. These seeds have a very strong, protective covering that allows them to float and survive for long distances and periods of time. The seedling may finally reach a point of its destination where conditions are favorable, and the roots will begin to bury into the ground, forming a new mangrove tree. The dispersal of these "live" young trees is called

vivipary In plants, vivipary occurs when seeds or embryos begin to develop before they detach from the parent. Plants such as some Iridaceae and Agavoideae grow cormlets in the axils of their inflorescences. These fall and in favourable circumstances the ...

, or birth of live young, very similar to mammals.

Flora

The range of newly deposited and well-established areas, varying water depth, and variations in salinity from the mixing of salt and fresh water create a diversity of habitats that are home to different mixes of species. On the shoreline pioneering species like the

Avicennia ''Avicennia'' is a genus of flowering plants currently placed in the bear's breeches family, Acanthaceae. It contains mangrove trees, which occur in the intertidal zones of estuarine areas and are characterized by its "pencil roots", which are ...

species ''

Avicennia alba ''Avicennia alba'' is a species of tropical mangrove in the family Acanthaceae. It is found growing in coastal and estuarine locations in India, Southeast Asia, Australia, and Oceania. Description ''A. alba'' forms a low, dense bushy crown ofte ...

'' and ''

Avicennia marina ''Avicennia marina'', commonly known as grey mangrove or white mangrove, is a species of mangrove tree classified in the plant family Acanthaceae (formerly in the Verbenaceae or Avicenniaceae). As with other mangroves, it occurs in the intertid ...

'' are usually the first to establish on coastal shores, with ''

Sonneratia ''Sonneratia'' is a genus of plants in the family Lythraceae. Formerly the Sonneratia were placed in a family called Sonneratiaceae which included both the ''Sonneratia'' and the ''Duabanga'', but these two are now placed in their own monotyp ...

'' growing in the coastal tidal creeks. Their complex root networks encourage further sedimentation and growth which then creates shade that allows ''Rhizophora mucronata '' to establish itself, ultimately supplanting the shade-intolerant ''Avicennia'' and ''Sonneratia''. Then ''

Rhizophora apiculata Rhizophora apiculata (''R. apiculata'') belongs to the Plantae kingdom under the Rhizophoraceae family. Currently ''R. apiculata'' is distributed throughout Australia (Queensland and Northern Territory), Guam, India, Indonesia, Malaysia, Microne ...

'' and ''

Bruguiera parviflora ''Bruguiera parviflora'' is a tree in the family Rhizophoraceae. The specific epithet ' is from the Latin meaning "small flowers". Description ''Bruguiera parviflora'' grows up to tall with a trunk diameter of up to . The bark is pale grey to p ...

'', (and occasionally ''

Bruguiera gymnorhiza ''Bruguiera gymnorhiza'', the large-leafed orange mangrove or oriental mangrove,) is a mangrove tree that grows usually to 7-20m high, but sometimes up to 35m, that belongs to the family Rhizophoraceae. It is found on the seaward side of mangrov ...

'') are the next in succession but still in waters that are more than 10% saline. Mature mangrove forests include ''

Xylocarpus ''Xylocarpus'' is a genus of plants in the mahogany family (Meliaceae). It includes two or three species of mangroves, native to coastal mangrove forests of the Western and Central Indo-Pacific, from eastern Africa to Tonga Tonga (, ; ) ...

'', Lunmitzera,'' and ''Heritiera. Papuan mahogany ''

Xylocarpus granatum ''Xylocarpus granatum'', commonly known as the cannonball mangrove, cedar mangrove, or puzzlenut tree, is a species of mangrove in the mahogany family (Meliaceae). It is found in Africa, Asia, Australasia and the Pacific Islands. It is a commo ...

'' can form monotypic stands, reaching up to 20 meters in height, with buttressed trunks up to a meter across. Where freshwater flows create a less salty

brackish Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuari ...

environment the mangrove palm ''

Nypa fruticans ''Nypa fruticans'', commonly known as the nipa palm (or simply nipa, from ms, nipah) or mangrove palm, is a species of palm native to the coastlines and estuarine habitats of the Indian and Pacific Oceans. It is the only palm considered adapte ...

'' is common, together with ''

'' and ''

Heritiera littoralis ''Heritiera littoralis'', commonly known as the looking-glass mangrove or tulip mangrove, is a mangrove tree in the family Malvaceae native to coastal areas of eastern Africa, Asia, Melanesia and northern Australia. The common name refers to the ...

''. Mangrove forests bordering

freshwater swamp forest Freshwater swamp forests, or flooded forests, are forests which are inundated with freshwater, either permanently or seasonally. They normally occur along the lower reaches of rivers and around freshwater lakes. Freshwater swamp forests are found ...

s include ''

Bruguiera sexangula ''Bruguiera sexangula'', commonly called the upriver orange mangrove, is a mangrove shrub or tree usually growing up to 15 m, occasionally 30 m, in height. Description ''Bruguiera sexangula'' may grow as a single-stemmed tree or multi- ...

'', ''

Camptostemon schultzii ''Camptostemon'' is a genus of flowering plants belonging to the family Malvaceae. Its native range is Central Malesia, Northern Australia. Species: *''Camptostemon aruensis'' *''Camptostemon philippinensis ''Camptostemon'' is a genus of f ...

'', '' Dolichandrone spathacea'', ''

Diospyros ''Diospyros'' is a genus of over 700 species of deciduous and evergreen trees and shrubs. The majority are native to the tropics, with only a few species extending into temperate regions. Individual species valued for their hard, heavy, dark tim ...

'' spp., ''

Excoecaria agallocha ''Excoecaria agallocha'', a mangrove species, belongs to the genus ''Excoecaria'' of the family Euphorbiaceae. The species has many common names, including blind-your-eye mangrove, blinding tree, buta buta tree, milky mangrove, poisonfish tree, ...

'', ''

'', and ''

'', along with typical freshwater swamp forest species, such as ''

Calophyllum ''Calophyllum'' is a genus of tropical flowering plants in the family Calophyllaceae. They are mainly distributed in Asia, with some species in Africa, the Americas, Australasia, and the Pacific Islands. History Members of the genus ''Calophyllu ...

'' spp., Kwila (''

Intsia bijuga ''Intsia bijuga'', commonly known as Borneo teak, Johnstone River teak, Kwila, Moluccan ironwood, Pacific teak, scrub mahogany and vesi, is a species of flowering tree in the family Fabaceae, native to the Indo-Pacific. It ranges from Tanzania and ...

''), '' Myristica hollrungii'', and '' Amoora cucullata''.

Fauna

These continuously changing woodlands do not have a great variety of mammals, although the greater sheath-tailed bat (''Emballonura furax'') is a near-endemic. Many species of birds also inhabit these forests including the New Guinea flightless rail, while endemic or near-endemic birds include the red-billed brush-turkey, Wallace's fruit-dove,

western crowned pigeon The western crowned pigeon (''Goura cristata''), also known as the common crowned pigeon or blue crowned pigeon, is a large, blue-grey pigeon with blue lacy crests over the head and dark blue mask feathers around its eyes. Both sexes are almost s ...

Salvadori's fig parrot Salvadori's fig parrot (''Psittaculirostris salvadorii'') is a species of parrot in the family Psittaculidae endemic to the northern part of the Papua province in Indonesia. Its name is in honour of Italian zoologist and ornithologist Tommaso ...

black lory The black lory (''Chalcopsitta atra''), also known as the rajah lory or red-quilled lory, is a medium-sized, blackish parrot with black bill, dark grey feet and long rounded tail. It has yellow and red under-tail. The sexes are similar. It is nat ...

, brown lory,

Papuan swiftlet The three-toed swiftlet or Papuan swiftlet (''Aerodramus papuensis'', formerly ''Collocalia papuensis'') is a species of swift. It is found in New Guinea. References three-toed swiftlet Birds of New Guinea three-toed swiftlet three-toed swif ...

, red-breasted paradise-kingfisher, white-bellied pitohui, and the olive-crowned flowerpecker. Reptiles recorded from the New Guinea mangroves on Daru and Bobo (Bristow) Islands, Western Province, PNG, during survey work were the

estuarine crocodile The saltwater crocodile (''Crocodylus porosus'') is a crocodilian native to saltwater habitats and brackish wetlands from India's east coast across Southeast Asia and the Sundaic region to northern Australia and Micronesia. It has been liste ...

(''Crocodylus porosus''), littoral skink (''Emoia atrocostata''),

mangrove monitor The mangrove monitor, mangrove goanna, or Western Pacific monitor lizard (''Varanus indicus'') is a member of the monitor lizard family with a large distribution from northern Australia and New Guinea to the Moluccas and Solomon Islands. It grows ...

(''Varanus indicus''),

amethystine python The amethystine python ('' Simalia amethistina'', formerly known as ''Morelia amethistina''), also known as the scrub python or ''sanca permata'' in Indonesian, is a species of non-venomous snake in the family Pythonidae. The species is found ...

(''Morelia amethistina''), crab-eating mangrove snake (''Fordonia leucobalia''), and Richardson's mangrove snake (''Myron richardsonii''). All are species strongly associated with southern New Guinea mangroves.

Ecological importance

Mangrove forests act as a "natural cleaner". For example, they intercept land-derived nutrients,

pollutants A pollutant or novel entity is a substance or energy introduced into the environment that has undesired effects, or adversely affects the usefulness of a resource. These can be both naturally forming (i.e. minerals or extracted compounds like oi ...

, and suspended matter before these contaminants reach deeper water. They also prevent coastal

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...

by stabilizing sediments provide nursery and spawning areas for commercially important fish and provide stop over sites for organisms such as

migratory birds Bird migration is the regular seasonal movement, often north and south along a flyway, between breeding and wintering grounds. Many species of bird migrate. Migration carries high costs in predation and mortality, including from hunting by ...

, mammals, and fish.

Threats and preservation

Even though this thick forest is hard to penetrate about 35% of the mangrove forests have been lost in the past two decades. These losses exceed those for tropical rain forests and

coral reefs A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of Colony (biology), colonies of coral polyp (zoology), polyps held together by calcium carbonate. Most coral reefs are built from stony corals, wh ...

. Mangrove trees grow on a narrow strip between land and ocean in river systems, between the latitudes 25 degrees N and 30 degrees S, and the constant renewal of the trees relies on rivers bringing nutrients to the coast in regular seasonal patterns. The limited distribution of this ecosystem adds to the delicacy of it. Many global changes such as an increased rise in sea water is largely thought to be responsible for the destruction of these mangrove forests. A few other factors such as

mariculture Mariculture or marine farming is a specialized branch of aquaculture (which includes freshwater aquaculture) involving the cultivation of marine organisms for food and other animal products, in enclosed sections of the open ocean ( offshore mari ...

agriculture Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people to ...

, and

urbanization Urbanization (or urbanisation) refers to the population shift from rural to urban areas, the corresponding decrease in the proportion of people living in rural areas, and the ways in which societies adapt to this change. It is predominantly t ...

have also contributed to the recent loss of mangrove habitats. Mangroves provide humans with

shrimp Shrimp are crustaceans (a form of shellfish) with elongated bodies and a primarily swimming mode of locomotion – most commonly Caridea and Dendrobranchiata of the decapod order, although some crustaceans outside of this order are refer ...

, fish, honey, lumber, and reptile skins. Without this tropical habitat, many of these products would be reduced in our market. Threats to mangroves in Bintuni Bay and on Daru and Bobo (Bristow) Islands, Western Province, PNG, includes cutting for firewood and charcoal burning. Cutters travel by canoe up creeks into the interior of the mangrove forest and clear-fell large areas of trees which from the outside appear untouched. The timber is sold in the market on Daru, an island which is home to 10% of the Western Province population i.e. some 15,000 people including immigrants from Indonesian New Guinea (Papua). It is doubtful the mangrove forests can sustain this level of harvesting. Kwila (''

'') and Papuan mahogany have more valuable timber and so are more vulnerable. Many steps around the world are being taken in an effort to conserve mangrove forests from being completely wiped out. Some of these efforts include replanting of trees by local communities, and the development of sustainable use systems within a community. This practice includes using resources from mangroves that is at a rate in which the ecosystem can recover.Maikut, Diana. "Ecology of Mangroves." 04 Jun 2004 Web.12 Apr 2009. . Meanwhile, there are four protected areas that include some coastal mangroves: Bintuni Bay Nature Reserve,

Lorentz National Park Lorentz National Park is a national park located in Central Papua, Indonesia, in the southwest of western New Guinea. With an area of 25,056 km2 (9,674 mi2), it is the largest national park in Southeast Asia. In 1999 Lorentz was declare ...

and the

Pulau Kimaam Wildlife Reserve Pulau may refer to: *Pulau virus (PuV), a novel strain of Nelson Bay orthoreovirus species *Pulau River, a river of West Papua and Papua New Guinea See also * List of islands of Malaysia – "Pulau" means "island" in the Malay language *Pulao (d ...

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...

and the Kikori Integrated Conservation and Development Project in Papua New Guinea.

References

{{Australasian mangroves Australasian ecoregions Central Indo-Pacific Ecoregions of Indonesia Ecoregions of New Guinea Ecoregions of Papua New Guinea * * Mangrove ecoregions Natural history of Western New Guinea