Category: Inland Aquatic Biomes.
Geographic Location: South Pacific Ocean.
Summary: The New Guinea freshwater swamp forests are filled with a wide array of flora and fauna, including some species indigenous to this inland aquatic biome. Ecosystems important to the survival of indigenous people are threatened by mining wastes and logging.
New Guinea, the second-biggest island in the world, was once attached to Australia and features a range of lowland, freshwater, and peat swamp forests across its Irian Jaya and Papua New Guinea sectors. The area of the Freshwater Swamp Forests biome mainly encompasses the foothills on the northern side of the central cordillera and down to the north coastal areas.
The region’s climate is tropical, with the temperature of the coastal plains averaging 82 degrees F (28 degrees C), 79 degrees (26 degrees C) in the inland and lower mountain areas, and 73 degrees (23 degrees C) in the higher mountain regions. The area’s relative humidity is a high 70–90 percent. There is a somewhat more dry season, June to September, while the rainy season is December to March. The western and northern parts of New Guinea get the most rainfall, which averages 400 inches (10,160 millimeters) per year.
Flora and Fauna
The island of New Guinea represents approximately 1 percent of the world’s landmass—but is home to nearly 10 percent of its vertebrate species and 7 percent of its vascular plant types. It also is home to the southern crowned pigeon (Goura scheepmakeri ), considered the largest known pigeon, as well as the smallest parrot, the red-breasted pygmy parrot (Micropsitta finschii ), and the longest lizard, Salvadore’s monitor lizard (Varanus salvadorii ). New Guinea is home to the world’s largest butterfly, the Queen Alexandra birdwing (Ornithoptera alexandrae ), and the conifer Araucaria , which can grow up to 230 feet (70 meters) and is thought to be the tallest tropical tree species on the planet.
Lowland swamp forests are located extensively in the northern portion of the island and particularly near the Sepik River. This area contains numerous habitats, including herbaceous swamp, Leersia grass swamp, Saccharum-phragmites grass swamp, Pseudoraphis grass swamp, mixed swamp savanna, Melaleuca swamp savanna, mixed swamp woodland, sago swamp woodland, pandan swamp woodland, mixed swamp forest, Campnosperma swamp forest, Teminalia swamp forest, and Melaleuca swamp forest.
The swamp forests include small- to medium-crowned dense to open areas, with 65–98-foot (20–30-meter) canopy. Sago palm (Metroxylon sagu ) and Pandanus spp. palm generally are located in this subcanopy, which also features Campnosperma brevipetiolata , C. auriculata, Terminalia canaliculata, Nauclea coadunata, and Syzygium spp., with Myristica hollrungii in delta areas.
The canopy along the Mamberamo River is approximately 147 feet (45 meters) high; it includes ficus and Pittosporum ramiflorum, as well as Timonius , Dillenia , and Nauclea .
The most abundant forest type in this ecoregion is lowland broadleaf evergreen, which is split into alluvial and hill varieties. The lowland alluvial forest has a multitiered and irregular canopy with many emergents, and a shrub and herb layer understory with climbers, epiphytes, and ferns. Palms are most common in the shrub layer. The canopy trees include Pometia pinnata, Octomeles sumatrana, Ficus spp., Alstonia scholaris, and Terminalia spp. Additional important genera include Pterocarpous, Artocarpus, Planchonella, Canarium, Elaeocarpus, Cryptocarya, Celtis, Dracontomelum, Sysoxylum, Syzygium, Vitex, Spondias , and Intsia .
The lowland hill forest contains a more open shrub layer than the lowland broadleaf evergreen forest, and a denser herb layer. The dominant canopy trees are Pometia, Canarium, Anisoptera, Cryptocarya, Terminalia, Syzygium, Ficus, Celtis, Dysoxylum, Buchanania, Koompassia, Dillenia, Eucalyptopsis, Vatica , and Hopea . Dense stands of Araucaria are scattered throughout this area.
New Guinea is home to more than 2,000 species of orchids and an equal number of ferns. Eight out of 10 of these plants are found nowhere else in the world, that is, they are endemic here. Of the climbing plants in the forests here, there are climbing palms or rattans that can grow to 787 feet (240 meters).
Biodiversity
There are 76 mammal species in this ecoregion, including 13 that are endemic or near-endemic, such as tube-nosed bat (Nyctimene draconilla ) and greater sheath-tailed bat (Emballonura furax ). The western part of the ecoregion is the only known site in New Guinea for the western ringtail possum (Pseudocheirus albertisi ). Others include Echymipera clara , Dorcopsis muelleri , Dorcopsis hageni , Emballonura furax , Hipposideros wollastoni , and Paraleptomys rufilatus .
Tree kangaroos like this Dendrolagus goodfellowi live in the New Guinea Freshwater Swamp Forests. New Guinea is only 1 percent of the world’s landmass but contains 10 percent of all vertebrate species.
NewGuineaFreshwaterSwampForests.jpg
The area is home to two types of tree kangaroo (Dendrolagus dorianus notatus and D. goodfellowi ), long-beaked echidna (Zaglossus bruijni ), and the mountain cuscus (Phalanger carmelitae ). New Guinea has a diverse animal population, including monotremes (mammals that lay eggs). These include the short-beaked echidna or spiny anteater (Tachyglossus aculeatus) and the long-beaked echidna. Other animals include the forest wallaby (Dorcopsis macleayi) , which are not found anywhere else, and 75 bat species and rodents.
Among the region’s many reptiles are Papuan olive python (Apodora papuana ); New Guinea snapping turtle (Elseya novaeguineae ); lined gecko, which also is known as the striped gecko (Gekko vittatus ); carpet python (Morelia spilota ), and spotted tree monitor (Varanus timorensis ).
There are more than 750 bird species, approximately half of which are endemic to New Guinea. Local bird families include Ptilonorhynchidae, Eopsaltriidae, Meliphagidae, and Paradisaeidae . Among the 16 endemic or near-endemic species is the vulnerable Salvadori’s fig-parrot (Psittaculirostris salvadorii ). Others include Edwards’s fig-parrot (P. edwardsii ), Papuan swiftlet (Aerodramus papuensis ), brown-headed crow (Corvus fuscicapillus ), white-bellied whistler (Pachycephala leucogastra ), brown-capped jewel-babbler (Ptilorrhoa geislerorum ), green-backed robin (Pachycephalopsis hattamensi ), and pale-billed sicklebill (Epimachus bruijnii ). There are more than 40 different kinds of bird of paradise, the landmark species of the island.
Many of the fish in freshwater here are migratory, coming from or going to the sea to spawn, such as the tarpon (Megalops cyprinoides ) and barramundi (Lates calcarifer ). Others are permanent inhabitants of freshwater habitats, such as fork-tailed catfish (Ariidae ), gudgeons (Cyprinidae ), gobies (Gobiidae), grunters (Terapontidae ), and jacks (Carangidae ). In the lowland rivers, where the waters are turbid and silty, are catfish, croakers (Sciaenidae ), silver biddies (Gerreidae ), and ponyfish (Leiognathidae ). In the floodplain lakes, swamps, and backwaters are rainbow fish, gobies, gudgeons, and catfish.
Environmental Issues
One of the largest protected areas in all of Southeast Asia-Oceania is Lorentz National Park in West Papua. At 5.8 million acres (2.35 million hectares), this World Heritage Site stretches 93 miles (150 kilometers) to the Arafura Sea, crossing a large area of freshwater swamp forest.
Because population density is low in the swampy areas of lowland New Guinea, the indigenous people have presented little threat to biodiversity, except for their overhunting. Logging also has been a threat, particularly in better-drained areas; this mostly impacts bird habitat. Hunting for bird meat and feathers may also be contributing to the decline of several bird species, such as the southern and northern cassowary (Casuarius casuarius johnsonii and C. unappendiculatus ), Salvadori’s teal (Salvadorina waigiuensis ), the black honey buzzard (Henicopernis infuscatus ), and the New Guinea harpy eagle (Harpyopsis novaeguineae ).
Other threats to the area come from open-pit copper and gold mines in the mountains upstream from large expanses of wetlands. Three of the world’s largest mines were allowed by the Indonesian and Papua New Guinea governments to operate without a system to retain mine tailings, which are often discharged into local waterways.
Climate change could unsettle the balance in this ecosystem, with the possibility of decreased rainfall increasing shore erosion and affecting the salinity of the waterways. Any change in precipitation could have an ripple effect on freshwater ecosystems; and rising sea levels could interact with increased flow from the rivers, creating more back pressure at river mouths. In either case, the water flow changes can impact both the flora and fauna of the biome.
Further Reading
Paijmans, K. “Wooded Swamps in New Guinea.” Ecosystems of the World. Amsterdam, Netherlands: Elsevier, 1990.
Ruddle, K., et al. Palm Sago: A Tropical Starch from Marginal Lands. Honolulu: University of Hawaii Press, 1978.
Wikramanayake, Eric, Eric Dinerstein, and Colby Loucks. Terrestrial Ecoregions of the Indo-Pacific . Washington, DC: Island Press, 2002.