The
New Guinea mangroves is a
mangroveMangroves are trees and shrubs that grow in saline coastal habitats in the tropics and subtropics – mainly between latitudes N and S. The saline conditions tolerated by various species range from brackish water, through pure seawater , to water of over twice the salinity of ocean seawater,...
ecoregionAn ecoregion , sometimes called a bioregion, is an ecologically and geographically defined area smaller than a "realm" or "ecozone". Ecoregions cover relatively large areas of land or water, and contain characteristic, geographically distinct assemblages of natural communities and species...
that covers portions of coastal
New GuineaNew Guinea, located north of Australia, is the world's second largest island. It became separated from the Australian mainland when the area now known as the Torres Strait flooded after the last glacial period. The name Papua has long been associated with the island...
. The New Guinea mangroves cover an area of 26,800 square kilometers (10,300 square miles), and cover extensive areas of coastline, particularly among the river mouths of New Guinea's south coast.
http://upload.wikimedia.org/wikipedia/commons/9/97/New_guinea_named.PNG
The New Guinea mangroves has the greatest diversity of mangrove species in the world.
The
New Guinea mangroves is a
mangroveMangroves are trees and shrubs that grow in saline coastal habitats in the tropics and subtropics – mainly between latitudes N and S. The saline conditions tolerated by various species range from brackish water, through pure seawater , to water of over twice the salinity of ocean seawater,...
ecoregionAn ecoregion , sometimes called a bioregion, is an ecologically and geographically defined area smaller than a "realm" or "ecozone". Ecoregions cover relatively large areas of land or water, and contain characteristic, geographically distinct assemblages of natural communities and species...
that covers portions of coastal
New GuineaNew Guinea, located north of Australia, is the world's second largest island. It became separated from the Australian mainland when the area now known as the Torres Strait flooded after the last glacial period. The name Papua has long been associated with the island...
. The New Guinea mangroves cover an area of 26,800 square kilometers (10,300 square miles), and cover extensive areas of coastline, particularly among the river mouths of New Guinea's south coast.
http://upload.wikimedia.org/wikipedia/commons/9/97/New_guinea_named.PNG
The New Guinea mangroves has the greatest diversity of mangrove species in the world. Rivers depositing sediment, together with waves and coastal currents, reshape the tidal zone where mangroves thrive. 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. There are several features that all species of mangroves have in common. These include tolerance to conditions of high soil salinity, tolerance to submergence in water, or waterlogged soil, and to low
oxygenOxygen Oxygen Oxygen (acid, literally "sharp", from the taste of acids) and -γενής (-genēs) (producer, literally begetter) is the element with atomic number 8 and represented by the symbol O...
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. These structures are covered with small holes call lenticles that allow the roots to breather 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.
Mangrove Development
Mangroves begin as a seed called a
propaguleIn horticulture, a propagule is any plant material used for the purpose of plant propagation. In asexual reproduction, a propagule may be a woody, semi-hardwood, or softwood cutting, leaf section, or any number of other plant parts. In sexual reproduction, a propagule is a seed or spore...
, 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
viviparyA viviparous animal is an animal employing vivipary: the embryo develops inside the body of the mother, as opposed to outside in an egg . The mother then gives live birth....
, or birth of live young, very similar to mammals.
Major Threats
About 35% of the of mangrove forests has been lost in the past two decades. These losses exceed those for tropical rain forests and coral reefs. Mangrove trees grow on a narrow strip between land and ocean, and between the latitudes 25 degrees N and 30 degrees S. 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
maricultureMariculture is a specialized branch of aquaculture involving the cultivation of marine organisms for food and other products in the open ocean, an enclosed section of the ocean, or in tanks, ponds or raceways which are filled with seawater. An example of the latter is the farming of marine fish,...
,
agricultureAgriculture is the production of food and goods through farming and forestry. Agriculture was the key development that led to the rise of human civilization, with the husbandry of domesticated animals and plants creating food surpluses that enabled the development of more densely populated and...
, and
urbanizationUrbanization is the physical growth of urban areas from rural areas as a result of population immigration to an existing urban area. Effects include change in density and administration services. While the exact definition and population size of urbanized areas varies amongdifferent countries,...
have also contributed to the recent loss of mangrove habitats. Mangroves provide humans with
shrimpShrimp are swimming, decapod crustaceans classified in the infraorder Caridea, found widely around the world in both fresh and salt water. Adult shrimp are filter feeding benthic animals living close to the bottom. They can live in schools and can swim rapidly backwards. Shrimp are an important...
, fish, honey, lumber, and reptile skins. Without this tropical habitat, many of these products would be reduced in our market. Threats to mangroves on Daru and Bobo (Bristow) Islands, Western Province, PNG, includes cutting for firewood. Cutters travel by canoe up creeks into the interior of the swamp and clear-fell large areas of mangroves 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 ie. some 15,000 people including immigrants from Indonesian New Guinea (Papua). It is doubtful the mangrove forests can sustain this level of harvesting.
Ecological Importance
Mangrove forests act as a "natural cleaner". For example, they intercept land-derived nutrients, pollutants, and suspended matter before these contaminants reach deeper water. They also prevent costal
erosionErosion is a gravity driven process that moves solids in the natural environment or their source and deposits them elsewhere...
by stabilizing sediments provide nursery and spawning areas for commercially important fish and provide stop over sites for organisms such as migratory birds, mammals, and fish.
Flora
Pioneering species like
Avicennia alba and
Avicennia marina are usually the first to establish on coastal shores, and
Sonneratia along tidal creeks. The complex root networks encourage further sedimentation and create shade that allows
Rhizophora mucronata to establish itself, ultimately supplanting the shade-intolerant
Avicennia and
Sonneratia.
Rhizophora apiculata and
Bruguiera parviflora, and occasionally
Bruguiera gymnorrhiza are the next in succession. Mature mangrove forests include
Xylocarpus, Lunmitzera, and
Heritiera. Xylocarpus granatum can form monotypic stands, reaching up to 20 meters in height, with buttressed trunks up to a meter across.
Where freshwater flows create a brackish environment,
Mangrove PalmNypa fruticans, known as the Attap Palm , Nipa Palm , and Mangrove Palm or Nipah palm , Dừa Nước , Gol Pata , Dani is the only palm considered a mangrove. This species, the only one in the genus Nypa, grows in southern Asia and northern Australia...
Nypa fruticans is common, together with
Xylocarpus granatum and
Heritiera littoralisHeritiera littoralis, the looking-glass mangrove is a large tree with wing shaped nuts, which is most easily recognised by the silvery scales on the underside of its leaves, which therefore appear green from top and white from below, although Litsea mellifera A.C. Smith , has the same type of leaves....
. Mangrove forests bordering
freshwater swamp forestFreshwater 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 in a range of climate zones, from boreal through...
s include
Bruguiera sexangula, Camptostemon schultzii, Dolichandrone spathacea, DiospyrosDiospyros is a genus of about 450-500 species of deciduous and evergreen trees. The majority are native to the tropics, with only a few species extending into temperate regions...
spp.,
Excoecaria agallocha, Heritiera littoralis, Rhizophora apiculata, and
Xylocarpus granatum, along with typical freshwater swamp forest species, such as
CalophyllumCalophyllum is a plant genus of around 180-200 species of tropical evergreen trees in the family Clusiaceae. Its members are native to Australasia, Madagascar, Eastern Africa, South and Southeast Asia, the Pacific islands, the West Indies and Latin America...
spp.,
Instia bijuga, Myristica hollrungii, and
Amoora cucullata.
Fauna
The New Guinea sheathtail bat,
Emballonura furax, is a
near-endemicEndemism is the ecological state of being unique to a particular geographic location, such as a specific island, habitat type, nation, or other defined zone. To be endemic to a place or area means that it is found only in that part of the world and nowhere else. For example, many species of lemur...
. Many species of birds also inhabit these forests. Some of which include the Red-billed brush turkey, Wallace's fruit dove, Western crowned-pigeon, Salvadori's fig parrot, Black lory, Brown lory, Papuan swiftlet, Red-breasted paradise-kingfisher, White-bellied pitohui, and the Olive-crowned flowerpecker. All of these birds are near-endemic species. Reptiles recorded from the New Guinea mangroves on Daru and Bobo (Bristow ) Islands, Western Province, PNG, during survey work were the Estuarine crocodile,
Crocodylus porosus, Littoral skink,
Emoia atrocostata, Mangrove monitor,
Varanus indicus, Amethystine python,
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.
Conservation
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.