Palawan rain forests | |
---|---|
Ecology | |
Realm | Indomalayan |
Biome | Tropical and subtropical moist broadleaf forests |
Geography | |
Area | 14,369 km2 (5,548 sq mi) |
Country | Philippines |
Coordinates | 9°36′N118°30′E / 9.6°N 118.5°E |
The Palawan rain forests ecoregion (WWF ID:IM0143) covers the Palawan Island Archipelago, centered on Palawan Island, the sixth largest island in the Philippines. The islands act as an ecological bridge between Borneo and the main islands of the Philippines, even though there were channels between the islands through the last ice age when sea levels were low. Biodiversity is high in the islands, with many endemic species, and with many genera shared with Borneo to the south. Pressure from logging is a concern for the forests of this region. [1] [2] [3] [4]
In addition to the main island of Palawan Island, the ecoregion includes Balabac Island to the south, Ursula Island, and the Calamian Islands to the north. Palawan Island is 260 km long and averages only 25–30 km wide. A mountain range runs up the middle of the island, with almost half of the slopes averaging over 30 degrees. The highest point is 2,085 metres (6,841 ft) at Mount Mantalingajan. The islands are relatively young, having been lifted up from the sea only 5-10 million years ago. [4]
The climate of the ecoregion is Tropical savanna climate - dry winter (Köppen climate classification (Aw)). This climate is characterized by relatively even temperatures throughout the year, and a pronounced dry season. The driest month has less than 60 mm of precipitation, and is drier than the average month.<ref">Kottek, M.; Grieser, J.; Beck, C.; Rudolf, B.; Rubel, F. (2006). "World Map of Koppen-Geiger Climate Classification Updated" (PDF). Gebrüder Borntraeger 2006. Retrieved September 14, 2019.</ref> [5] In the Palawans, the wet season lasts from June to October. The dry season for much of the island is November to May, but only a few months long in the north. [1]
About two thirds of the islands is covered in closed broadleaf evergreen forest, 10% in other closed forest, 15% in open forest or herbaceous cover and only about 5% in human settlement or agriculture. [3] Much of this forest below the highlands has been cut previously, and pressure from logging and conversion of land to agriculture has reduced the quality of much of the forest. [1] The forests nearest the coast are beech forests, transitioning to lowland rain forest dominated by trees of the Dipterocarpaceae family, Agalai, various species of Ficus , Water gum (Tristania), Broad leaved ballart (Exocarpos latifolius), and Swintonia foxworthyi . Montane rainforest is found at higher elevations (800 to 1,200 meters), and semi-deciduous forest is found in the rain shadow on the east side of the main island.
The southern part of the main island has different forest types that depend on the soil. Large areas are limestone forest, featuring cathedral cactus (Euphorbia lacei), Aglaia argentea , and species of Antidesma , Drypetes , and Gomphandra . There are ultramafic forests around Victoria Peak that support plants that may be associated with soils having heavy metals. [1] Parts of the southern forest are dominated by Casuarina . [1]
There are high levels of endemic species of mammals on the islands, but many of the genera are shared with Borneo, indicating that the Palawans were once part of Sundaland (the combined islands to the west), but have been separated for enough time to develop their own faunal communities. [4]
Over 80% of the ecoregion is protected in some form. [3] These protected areas include:
The Queensland tropical rain forests ecoregion covers a portion of the coast of Queensland in northeastern Australia and belongs to the Australasian realm. The forest contains the world's best living record of the major stages in the evolutionary history of the world's land plants, including most of the world's relict species of plants from the ancient supercontinent of Gondwana. The history of the evolution of marsupials and songbirds is also well represented.
The Sakhalin Island taiga ecoregion covers most of Sakhalin Island, the largest island of Russia, which is separated from the mainland by the Sea of Okhotsk and the Sea of Japan. The region is one of taiga, coniferous and mixed broad leaf forest landscape, with mixed larch forests at the lower elevations and shrubs at higher elevations. The vegetation is influenced by a maritime climate that is relatively warmer than the colder continental taiga in Siberia to the west. A long, thin island, 1,000 km by 200 km, Sakhalin is connected to the mainland by ice bridges in the winter, so it shares certain flora and fauna species. It is in the Palearctic realm, and mostly in the taiga biome with a Humid continental climate, cool summer climate. It covers 403,504 km2 (155,794 sq mi).
The Mato Grosso tropical dry forests (NT0140), also called the Mato Grosso seasonal forests, is an ecoregion in central Brazil to the south of the Amazon region. It contains vegetation in the transition between the Amazon rainforest to the north and the cerrado savanna to the south. The opening of highways through the region has caused rapid population growth, deforestation and pollution.
The Hainan Island monsoon rain forests ecoregion covers mountainous interior of Hainan Island in China. The tropical forests receive over 1,000 mm/year of rain, heavily concentrated in the summer rainy season. The island has high levels of biodiversity, with over 4,200 plant species, 630 of which are endemic to the island. The region is under ecological pressure from deforestation for agriculture and timber extraction.
The Northern Annamites rain forests ecoregion covers the rugged and relatively unexplored northern Annamite Mountains of central Laos and Vietnam. There are high numbers of endemic plant species, and the relative remoteness and isolation of the area supports many rare and endangered animals. Rainfall is somewhat less than the lowland rainforest of the lower elevations in Vietnam, and the temperatures slightly cooler due to the higher elevation.
The Southern Annamites montane rain forests ecoregion covers a region of high biodiversity in the central and southern mountains of the Annamite Range in Vietnam. Terrain ranges from wet lowland forest to evergreen hardwood and conifer montane rain forest. There is a short dry season centered on January–February, but fog and dew are common throughout the year and support a lush forest character.
The Eastern Java–Bali montane rain forests ecoregion covers the higher altitude mountain rainforests on the eastern side of the island of Java, and most of the center of the island of Bali in Indonesia. The region has a number of active volcanoes, but is under pressure from growing human populations pushing into higher elevations and more marginal land. With elevations rising from sea level to 3,426 metres (11,240 ft), and precipitation varying between rainforest and drier forest levels, the area has many different forest types – evergreen, deciduous and semi-alpine.
The Eastern Java-Bali rain forests ecoregion covers the lowland areas of the eastern half of the island of Java, and the island of Bali, in Indonesia. This ecoregion is distinct from the Eastern Java-Bali montane rain forests, which exists at higher elevations where mountain forest habitat dominates. Very little of the natural lowland rainforest remains in its pre-human settlement state.
The Sumatran lowland rain forests ecoregion covers the lowland forests running the length of the island of Sumatra in Indonesia. The region is one of exceptionally high biodiversity, similar to Borneo and New Guinea islands. Many endangered mammals species are present, and over 450 species of birds have been found in the region. In recent years, illegal logging and human encroachment have put great strain on this ecoregion.
The Mindanao montane rain forests ecoregion covers the montane forests - the zone between the lowland forest and the treeline - in the mountains on the island of Mindanao in the Philippines. Because the ecoregion covers only elevations above 1,000 metres (3,300 ft), it exists in seven discontinuous patches surrounded by lowland rainforest. Biodiversity is high, both because of the isolation of separate mountain ranges that have led to species variation within the island, and because of the altitude zonation. Because most of the surrounding lowland forest has been cleared for human use, the montane regions have become an important refuge for rare and endemic species.
The Greater Negros–Panay rain forests ecoregion covers the central Visayan Islands in the Philippines, including the islands of Panay, Negros, Cebu, Masbate, Sibuyan, Ticao, Guimaras, Romblon, Tablas, Siquijor, and Bohol, but excludes Leyte and Samar. During the last ice age, these were all on the same island. The lack of a land bridge to Asia during the ice age kept most Asian megafauna, including elephants and tigers, from reaching the Philippines and the Visayan Islands, which hosts many unique and endemic species with some exclusive only to an island.
The Mindanao–Eastern Visayas rain forests ecoregion covers the lowland rain forests of the island of Mindanao and of the easternmost of the Visayas Islands in the Philippines. Although 63% of this ecoregion is covered with closed broadleaf evergreen forest or open forest, much of this has been disturbed in the past by human activity, and many of the rare species of the area have been relegated to the isolated areas or higher elevations.
The Mindoro rain forests ecoregion covers the island of Mindoro, which lies between the island of Luzon and the Palawan Archipelago in the Philippines. The island has been subject to heavy commercial logging, with the only original forests remaining on the high ridge of the central mountain range. Logging has been reduced long enough on the east side of the mountains to support a regrown forest and a number of endemic species.
The Sumatran peat swamp forests ecoregion covers the low-lying peat swamp forests along the northeast coast of the island of Sumatra in Indonesia. As is typical for peat swamp forests, this ecoregion lies between a thin strip of saltwater-affected mangroves on the coast, and freshwater swamps and lowland rainforest forest on better drained soils further inland. Because the peat soil has relatively low nutrient levels, this ecoregion has been less used for agriculture, but burning and clearance has degraded half of the forest.
The Southwest Borneo freshwater swamp forests ecoregion covers a number disconnected patches of freshwater swamp forest along the southwestern coasts of Borneo. The swamps are generally set back a few kilometers or two from the sea by the saltwater-affected Sunda Shelf mangroves The relatively fertile, flat soil has led to much of this ecoregion being converted to agriculture.
The Western Java montane rain forests ecoregion covers the montane rain forest above 1,000 meters in the volcanic mountain ridges in the west of the island of Java in Indonesia. Several mammals and bird species are found only in this ecoregion, including the Javan mastiff bat (Otomops formosus) and the Volcano mouse (Mus vulcani). Only about one-fifth of the original rainforest remains in its original state, as human pressures are encroaching on the mountain slopes.
The Western Java rain forests ecoregion covers the lowland rain forests below 1,000 meters in elevation in the western half of the island of Java in Indonesia. There are a variety of forest types - evergreen, semi-evergreen, moist deciduous, and even some patches of freshwater swamp. The forests have degraded by conversion of the low areas to agriculture, and by logging. National parks protect some of the last remaining untouched rain forest. A number of endangered mammals are found in the ecoregion, including the Javan rhinoceros, the silvery gibbon, and the Javan surili.
The Miskito pine forests ecoregion covers lowland pine forests and savanna along much of the Mosquito Coast in northeastern Nicaragua and southeastern Honduras. Pines are adapted to grow in the poor soil, relative to the surrounding moist forest, and repeated burning have left one species – the Caribbean pine – dominant. Although the ecoregion receives high levels of rain, the hard soils, repeated burning, and exposure to hurricanes have left expanses of 'pine savanna' and seasonal wetlands. The area is thinly settled by humans and there is little crop agriculture.
The Trinidad and Tobago moist forests ecoregion covers most of Trinidad Island and Tobago Island near the coast of South America where the southeastern Caribbean Sea meets the Atlantic Ocean. Small portions of the islands around river estuaries and coastal lowlands are mangroves or dry forests. Species diversity is very high, in particular for plants and birds. Tobago, being much smaller, has fewer species.
The Cayman Islands dry forests ecoregion covers about half of the Cayman Islands in the Caribbean Sea. The other half of the low-lying islands are mangroves. The dry forests of Grand Cayman have been heavily cleared or degraded for human development; the less populated islands have more intact wooded habitat.