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Location Thailand, Ang Thong,Bangkok Metropolis,Nakhon Pathom,Nonthaburi,Pathum Thani,Phra Nakhon Si Ayutthaya,Samut Sakhon,Suphan Buri
Central coordinates 100o 27.00' East  14o 15.00' North
IBA criteria A1, A4i, A4iii
Area 190,000 ha
Altitude 0 - 20m
Year of IBA assessment 2004

Bird Conservation Society of Thailand

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.

Key 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)

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Painted Stork Mycteria leucocephala resident  2004  present  A4i  Near Threatened 
Mesophoyx intermedia unknown  2004  present  A4i  Not Recognised 
Spot-billed Pelican Pelecanus philippensis non-breeding  2004  present  A1  Near Threatened 
Greater Spotted Eagle Clanga clanga winter  2004  present  A1  Vulnerable 
Grey-headed Lapwing Vanellus cinereus winter  2004  present  A4i  Least Concern 
Manchurian Reed-warbler Acrocephalus tangorum winter  2004  present  A1  Vulnerable 
A4iii Species group - waterbirds unknown  2004  20,000 individuals  unknown  A4iii   

IBA Monitoring

2013 high not assessed low

Biological resource use hunting & collecting terrestrial animals - intentional use (species being assessed is the target) past (and unlikely to return) and no longer limiting whole area/population (>90%) no or imperceptible deterioration low
Human intrusions and disturbance work and other activities happening now some of area/population (10-49%) moderate to rapid deterioration high
Pollution industrial & military effluents - type unknown/unrecorded happening now some of area/population (10-49%) moderate to rapid deterioration high
Residential and commercial development commercial and industrial development happening now some of area/population (10-49%) slow but significant deterioration medium

Some of site covered (10-49%)  A management plan exists but it is out of date or not comprehensive  Substantive conservation measures are being implemented but these are not comprehensive and are limited by resources and capacity  low 

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Bung Chawak Non Hunting Area 320 protected area contained by site 320  
Wat Phai Lom Non Hunting Area 11 protected area contained by site 11  
Wat Ratsattha Krayaram Non Hunting Area 7 protected area contained by site 7  
Wat Tan En Non Hunting Area 16 protected area contained by site 16  


IUCN habitat Habitat detail Extent (% of site)
Artificial - terrestrial   -
Wetlands (inland)   -

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.)

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Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Lower Central Basin. Downloaded from on 22/10/2016

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