| Tongan tropical moist forests | |
|---|---|
 Nuku Island, Tonga | |
 Map of Tonga | |
| Ecology | |
| Realm | Oceanian |
| Biome | tropical and subtropical moist broadleaf forests |
| Geography | |
| Area | 549 km2 (212 sq mi) |
| Countries | |
| Conservation | |
| Conservation status | Critical/endangered [1] |
| Global 200 | South Pacific Islands forests |
| Protected | 117 km² (21%) [2] |
The Tongan tropical moist forests is a tropical and subtropical moist broadleaf forests ecoregion that includes the Tonga archipelago and Niue.
The ecoregion includes the Tonga archipelago, a group of 170 islands that extends 800 km north to south between 15º to 23ºS latitude and 173º to 177º W longitude, and comprise the nation of Tonga. It also includes Niue, which lies 400 km east of Tonga at 19º S latitude and 169º W longitude. [1]
The Tonga archipelago lies at the boundary of the Pacific and the Australian tectonic plates, and the islands were created by the subduction of the Pacific Plate under the Australian Plate. [1] The islands on the eastern side of the chain are mostly made up of uplifted coraline rocks lying atop blocks of oceanic or continental crust. Some of the larger eastern islands are Foa, Lifuka, Vavaʻu, 'Eua, and Tongatapu. Several of the islands on the western side of the chain are of stratovolcanos, including 'Ata, Tofua, Kao, Late, and Fonualei in the south, and Niuafo'ou, Niuatoputapu, and Tafahi in the north. [3] The highest peak in the islands is 1,030 metres on Kao. Many islands have fringing coral reefs, and others have become coral atolls as the central islands eroded away or subsided. [1]
Niue is an uplifted coral atoll, with cliffs along the shoreline and without a fringing coral reef. It covers an area of 259 km2. [1]
The islands have been inhabited for about 3000 years.
The ecoregion has a humid tropical climate. Mean daily temperatures generally range from 24º to 30 °C in February, the warmest month, to 20º to 26 °C in August, the coolest month. Average annual rainfall is 2000 mm or more, and higher on windward slopes and at higher elevations. Rainfall is generally higher between December and April. Leeward lowlands can experience seasonal droughts between May and November. [1]
The natural vegetation is moist broadleaf forest.
Tropical lowland rain forests predominate below 500 meters elevation. Evergreen trees form a continuous canopy up to 30 meters in height. Common canopy trees include Diospyros spp., Rhus taitensis, Alphitonia zizyphoides, Calophyllum neo-ebudicum, Cryptocarya turbinata, Elattostachys apetala, Litsea mellifera, Maniltoa grandiflora, Myristica hypargyraea, Zanthoxylum pinnatum, Garcinia myrtifolia, Neonauclea forsteri, Didymocheton tongensis (on 'Eua), Podocarpus pallidus, Inocarpus fagifer, Erythrina fusca, Pisonia grandis, Pittosporum arborescens, Garuga floribunda, Ficus obliqua, Pleiogynium timoriense , and Cynometra grandiflora . [1] [4] The understorey includes dense clumps of the fern Dicranopteris linearis and the shrubs Piper puberulum and Psychotria insularum . [1]
On coastal dunes and relatively recent lava and ash deposits where soils are thinner and drier, forests of Casuarina equisetifolia predominate, with low trees and shrubs including Pandanus tectorius, Syzygium dealbatum, Hibiscus tiliaceus , and Scaevola taccada . [1]
Littoral forests of Hernandia nymphaeifolia, Barringtonia asiatica , and Casuarina equisetifolia grow closest to the coast in areas with salt spray. Immediately inland are coastal forests with Pisonia grandis and Excoecaria agallocha as the predominant trees. [4]
Mangrove scrub and mangrove forest are found in saltwater wetlands on coral atolls and around the shores of the larger islands' coastal lagoons. [1] Mangrove scrub is found on estuaries and reef flats and on the edges of mangrove forests. The small- to medium-sized trees Rhizophora mangle, Rhizophora stylosa , and Lumnitzera littorea are dominant. Where conditions are favorable mangrove forests dominated by Bruguiera gymnorhiza with Xylocarpus moluccensis and X. granatum replace the mangrove scrub. [3]
Montane forests are found above 500 metres elevation on the island of Tafahi. The climate is cooler and more humid than that of the lowland forests. Characteristic montane forest tree species include Syzygium spp., Fagraea berteroana, Bischofia javanica, Hernandia moerenhoutiana, Astronidium spp., and Reynoldsia spp. Other montane plant communities are upland volcanic scrub on Kao's young volcanic slopes, and fernlands dominated by Dicranopteris linearis with Lycopodium cernuum and Miscanthus floridulus in highland areas of 'Eua disturbed by human-caused fires. [3]
There are 419 native species of vascular plants in the Tonga, and approximately 3% are endemic. [1]
Plants endemic to Tonga include Alphitonia franguloides var. obtusa, Arytera bifoliata, Grewia amicorum, Grewia populoides, Guioa lentiscifolia, Meiogyne amicorum, Oldenlandia debilis, Pandanus amicalis, Pandanus tongatapuensis, Pandanus vavauensis, Phyllanthus amicorum, Pittosporum yunckeri, Psychotria euaensis, Scaevola porrecta , and Xylosma smithiana . [5]
Several species are endemic to one or two islands: [5]
Peperomia pallida var. niueana, Myoporum nieuanum , and the orchid Dendrobium niueense are endemic to Niue. [6]
There are no native land mammals in the ecoregion. Native bats include the Pacific flying fox (Pteropus tonganus) and Pacific sheath-tailed bat (Emballonura semicaudata). The black rat (Rattus rattus) and brown rat (R. norvegicus) were introduced to the islands by humans, and have decimated the island's birds. [1]
Tonga has native 20 species of land and freshwater birds. The Tongan whistler (Pachycephala jacquinoti) is an endemic species found the Vava'u Group. The Niuafo'ou megapode (Megapodius pritchardii) is endemic to Niuafo'ou island. Other native birds include the red shining parrot (Prosopeia tabuensis) and blue-crowned lorikeet (Vini australis). [1]
The islands are home to numerous seabirds, including brown noddy (Anous stolidus), Phoenix petrel (Pterodroma alba), and bristle-thighed curlew (Numenius tahitiensis). Seabird breeding colonies are mostly limited to offshore islets free of rats, which prey on eggs and chicks. [1]
Niue has 12 native species of land birds and six species of seabirds, including two endemic subspecies. [1]
There are 20 known species of reptiles in the ecoregion. They include the Lau banded iguana (Brachylophus fasciatus), the boa Candoia bibroni , nine species of gecko, and nine species of skink. The skink Tachygia microlepsis is now considered extinct. Fossil remains of an giant land iguana have been found, which became extinct after the first humans arrived. [1]
A 2017 assessment found that 117 km2, or 21%, of the ecoregion is in protected areas. [2]
Located in Oceania, Tonga is a small archipelago in the South Pacific Ocean, directly south of Samoa and about two-thirds of the way from Hawaii to New Zealand. It has 169 islands, 36 of them inhabited, which are in three main groups – Vavaʻu, Haʻapai, and Tongatapu – and cover an 800-kilometre (500-mile)-long north–south line. The total size is just 747 km2 (288 sq mi). Due to the spread out islands it has the 40th largest Exclusive Economic Zone of 659,558 km2 (254,657 sq mi).
The Vanuatu rain forests are tropical and subtropical moist broadleaf forests ecoregion which includes the islands of Vanuatu, as well as the Santa Cruz Islands group of the neighboring Solomon Islands. It is part of the Australasian realm, which includes neighboring New Caledonia and the Solomon Islands, as well as Australia, New Guinea, and New Zealand.
The Hawaiian tropical rainforests are a tropical moist broadleaf forest ecoregion in the Hawaiian Islands. They cover an area of 6,700 km2 (2,600 sq mi) in the windward lowlands and montane regions of the islands. Coastal mesic forests are found at elevations from sea level to 300 m (980 ft). Mixed mesic forests occur at elevations of 750 to 1,250 m, while wet forests are found from 1,250 to 1,700 m. Moist bogs and shrublands exist on montane plateaus and depressions. For the 28 million years of existence of the Hawaiian Islands, they have been isolated from the rest of the world by vast stretches of the Pacific Ocean, and this isolation has resulted in the evolution of an incredible diversity of endemic species, including fungi, mosses, snails, birds, and other wildlife. In the lush, moist forests high in the mountains, trees are draped with vines, orchids, ferns, and mosses. This ecoregion includes one of the world's wettest places, the slopes of Mount Waiʻaleʻale, which average 373 in (9,500 mm) of rainfall per year.
Lakeba is an island in Fiji’s Southern Lau Archipelago; the provincial capital of Lau is located here. The island is the tenth largest in Fiji, with a land area of nearly 60 square kilometers. It is fertile and well watered, and encircled by a 29-kilometer road. Its closest neighbors are Aiwa and Nayau. Separated by deep sea from the latter but only by shallow waters from the former, when sea levels were lower during glacial episodes Lakeba and Aiwa formed one large island.
The Tongan megapode is a species of bird in the megapode family, Megapodiidae, currently endemic to Tonga. The species is also known as the Polynesian megapode, and as the Niuafo'ou megapode after the island of Niuafo'ou to which it was restricted for many years. The specific epithet honours British consul William Thomas Pritchard.
The Caribbean bioregion is a biogeographic region that includes the islands of the Caribbean Sea and nearby Atlantic islands, which share a fauna, flora and mycobiota distinct from surrounding bioregions.
Niua is a division of the Kingdom of Tonga, namely the northernmost group of islands. It consists of three islands which together have an area of 71.69 km2 and a population of 1,150. The largest village is Hihifo on Niuatoputapu. Piu'o Tafahi is the highest point with an elevation of 560 m.
The Samoan tropical moist forests are a tropical moist broadleaf forest ecoregion in the Samoan Islands of the Pacific Ocean.
The Fiji tropical moist forests is a tropical moist forest ecoregion in Fiji and Wallis and Futuna. It covers the windward sides of Viti Levu and Vanua Levu, Fiji's largest islands, as well as the smaller Fijian islands and the three islands that make up Wallis and Futuna, an overseas territory of France.
The Cook Islands tropical moist forests is a tropical and subtropical moist broadleaf forests ecoregion that covers the Southern Cook Islands in the Cook Islands.
The Tubuai tropical moist forests is a tropical and subtropical moist broadleaf forests ecoregion in French Polynesia. It covers the Austral Islands.
The Society Islands tropical moist forests is a tropical and subtropical moist broadleaf forests ecoregion in the Society Islands of French Polynesia.
The Marquesas tropical moist forests is a tropical and subtropical moist broadleaf forests ecoregion in the Marquesas Islands of French Polynesia.
The Tuamotu tropical moist forests is a tropical and subtropical moist broadleaf forests ecoregion in the Tuamotu Archipelago of French Polynesia and the Pitcairn Islands.
The Central Polynesian tropical moist forests is a tropical and subtropical moist broadleaf forests ecoregion in Polynesia. It includes the northern group of the Cook Islands, the Line Islands in Kiribati, and Johnston Atoll, Jarvis Island, Palmyra Atoll, and Kingman Reef which are possessions of the United States.
The Western Polynesian tropical moist forests is a tropical and subtropical moist broadleaf forests ecoregion in Polynesia. It includes Tuvalu, the Phoenix Islands in Kiribati, Tokelau, and Howland and Baker islands, which are possessions of the United States.
The Eastern Micronesia tropical moist forests is a tropical and subtropical moist broadleaf forests ecoregion in Micronesia. It includes the Marshall Islands, Banaba and the Gilbert Islands in Kiribati, Nauru, and Wake Island, a possession of the United States.
The Carolines tropical moist forests is a tropical and subtropical moist broadleaf forests ecoregion in Micronesia. It includes the central and eastern Caroline Islands in the Federated States of Micronesia.
Syzygium dealbatum is a species of flowering plant in the myrtle family, Myrtaceae. It is a tree native to Niue, the Samoan Islands, Tonga, and Wallis and Futuna.
Cryptocarya turbinata is a species of flowering plant in the laurel family, Lauraceae. It is a tree native to Fiji, Niue, the Samoan Islands, Tonga, and Vanuatu.
{{cite journal}}: CS1 maint: date and year (link) Supplemental material 2 table S1b.