Lower Central Basin (15340)
Thailand, Asia
Site overview
KBA status: confirmed
Year of last assessment: 2012
National site name: Lower Central Basin
Central coordinates: Latitude: 14.2500, Longitude: 100.4500
System: freshwater, terrestrial
Elevation (m): 0 to 20
Area of KBA (km2): 14199.8484
KBA classification: Global/Regional TBD
Legacy site: Yes
Site details
Site description: The IBA comprises the Lower Central Plain of the Chao Phraya River, which extends inland from the Gulf of Thailand and encompasses the environs of Bangkok. The Lower Central Plain was formerly a vast area of natural and semi-natural swamps, well-watered throughout the year by four major rivers: the Chao Phraya, Bang Pakong, Pasak and Mae Klong. However, the area was the focus of massive irrigation system developments in the early 20th Century, and current land-use is dominated by intensive rice cultivation, with only small remnant patches of wetland habitats and extensive agriculture. Due to high human population density and levels of use, it is unrealistic for anything but a small fraction of the area to be placed under strict conservation management. However, the Lower Central Plain was designated as a single IBA because conservation actions aimed at controlling hunting and promoting compatible forms of land-use are required across the whole area. Sites within the IBA currently afforded some protection include Wat Phai Lom (11 ha), Wat Tan En (16 ha), Bung Chawak (320 ha) and Wat Ratsattha Krayaram (7 ha) Non-hunting Areas.
Rationale for qualifying as KBA: This site qualifies as a Key Biodiversity Area of international significance because it meets one or more previously established criteria and thresholds for identifying sites of biodiversity importance (including Important Bird and Biodiversity Areas, Alliance for Zero Extinction sites, and Key Biodiversity Areas) The site has been reviewed and re-confirmed as a KBA in the process of compiling the revised 2011 CEPF Ecosystem Profile for the Indo-Burma Hotspot.
Additional biodiversity: Several globally threatened species occur in the Lower Central Plain and the area regularly supports well in excess of 20,000 waterbirds. A number of globally threatened species regularly occur at the site, some of them in significant numbers. The site regularly supports significant numbers of wintering Greater Spotted Eagle Aquila clanga and Manchurian Reed Warbler Acrocephalus tangorum, and very low numbers of wintering Baer's Pochard Aythya baeri and Imperial Eagle Aquila heliaca. Spot-billed Pelican Pelecanus philippensis is an occasional non-breeding visitor, while Baikal Teal Anas formosa and Greater Adjutant Leptoptilos dubius are vagrants. In addition, there are historical records of the globally vulnerable Lesser Adjutant Leptoptilos javanicus. In recent years, the site has supported over 1% of the Asian biogeographic population of Grey-headed Lapwing Vanellus cinereus, Intermediate Egret Mesophoyx intermedia and the globally near-threatened Painted Stork Mycteria leucocephala. Other globally near-threatened species to occur at the site in significant numbers are Asian Golden Weaver Ploceus hypoxanthus and Black-headed Ibis Threskiornis melanocephalus, while Oriental Darter Anhinga melanogaster and Band-bellied Crake Porzana paykullii have also been recorded, although not in significant numbers. Non-bird biodiversity: Fish Giant Freshwater Stingray Himantura chaophraya (EN) White-edged Freshwater Whipray Himantura signifer (EN)
Habitats
Summary of habitats in KBA: The IBA comprises the Lower Central Plain of the Chao Phraya River, which extends inland from the Gulf of Thailand and encompasses the environs of Bangkok. The Lower Central Plain was formerly a vast area of natural and semi-natural swamps, well-watered throughout the year by four major rivers: the Chao Phraya, Bang Pakong, Pasak and Mae Klong. However, the area was the focus of massive irrigation system developments in the early 20th Century, and current land-use is dominated by intensive rice cultivation, with only small remnant patches of wetland habitats and extensive agriculture. Due to high human population density and levels of use, it is unrealistic for anything but a small fraction of the area to be placed under strict conservation management. However, the Lower Central Plain was designated as a single IBA because conservation actions aimed at controlling hunting and promoting compatible forms of land-use are required across the whole area. Sites within the IBA currently afforded some protection include Wat Phai Lom (11 ha), Wat Tan En (16 ha), Bung Chawak (320 ha) and Wat Ratsattha Krayaram (7 ha) Non-hunting Areas.
| IUCN Habitat | Coverage % | Habitat detail |
|---|---|---|
| Artificial - Terrestrial | 50 | |
| Wetlands(Inland) | 50 |
Threats
Summary of threats to biodiversity at KBA: The main threats to biodiversity at the site arise from failure to fully mitigate the environmental impacts of development in the area. Agricultural intensification is leading to the loss of remaining semi-natural wetland habitats and areas of extensive agriculture, which are also important habitats for many bird species. Urban expansion, infrastructure development and industrial development are further causes of habitat loss. In addition, pollution, in the form of agrochemicals and domestic and industrial waste, is a further threat to biodiversity at the site.
| Threat level 1 | Threat level 2 | Threat level 3 | Timing |
|---|---|---|---|
| Pollution | Industrial & military effluents | Type Unknown/Unrecorded | Ongoing |
| Biological resource use | Hunting & collecting terrestrial animals | Intentional use (species being assessed is the target) | Only in the past and unlikely to return |
| Residential & commercial development | Commercial & industrial areas | Ongoing | |
| Human intrusions & disturbance | Work & other activities | Ongoing |
Additional information
References: Bird Conservation Society of Thailand Bulletin 18(7): 13-14 (July 2001). BirdLife International (1998) Proceedings of the Thailand IBA workshop, Bangkok, November 1998. Unpublished report. BirdLife International (2001) Threatened birds of Asia: the BirdLife International Red Data Book. Cambridge, UK: BirdLife International. Lopez, A. and Mundkur, T. (1997) The Asian Waterfowl Census 1994-1997: results of the coordinated waterbird census and an overview of the status of wetlands in Asia. Kuala Lumpur: Wetlands International. Office of Environmental Policy and Planning (1999) Directory of internationally important wetlands in Thailand. Bangkok: Ministry of Science, Technology and Environment. (In Thai.)