email a friend
printable version
Location Thailand, Bangkok Metropolis,Chachoengsao,Chon Buri,Phetchaburi,Samut Prakan,Samut Sakhon,Samut Songkhram
Central coordinates 100o 40.00' East  13o 30.00' North
IBA criteria A1, A4i, A4iii
Area 100,000 ha
Altitude 0 - 2m
Year of IBA assessment 2004

Bird Conservation Society of Thailand

Site description The IBA comprises a 195 km-long section of the coastal zone of the Inner Gulf of Thailand, from Laem Phak Bia in the west to Chonburi in the east. Four major rivers, the Mae Klong, Tha Chin, Chao Phraya and Bang Pakong, discharge into the Gulf of Thailand along this stretch of coastline, creating extensive areas of intertidal habitats. The site includes an estimated 23,500 ha of intertidal mudflats, extending over 2 km from the shoreline at low tide in places. Previously, the Inner Gulf of Thailand supported a large area of mangroves. However, this habitat has now been extensively converted to other land uses, and, currently, less than 1,600 ha of mangroves remain, much of which consists of regenerating Avicennia-dominated scrub. Areas that previously supported mangroves now support anthropogenic habitats, including at least 10,600 ha of saltpans and from 40,000 to 80,000 ha of shrimp ponds, many of which are abandoned. Inland of the intertidal zone, the site supports large areas of Suaeda-dominated coastal flats, fish-ponds and rice paddies. Due to high levels of human use and high human population densities, it is unrealistic for more than a small part of the site to be placed under strict conservation management. However, the whole site was defined as a single IBA, because conservation actions aimed at controlling over-exploitation of natural resources and promoting compatible forms of land use are required across the whole site. In 2001, an 87,500 ha section of the IBA around Don Hoi Lot in Samut Songkhram province was designated as a Ramsar Site.

Key Biodiversity To date, there have been no comprehensive surveys of the avifauna of the entire IBA. Rather, most available data are from individual sites within the IBA, including Bang Poo, Wat Asokaram, Kalong, Rangchan, Khok Kham, Don Hoi Lot, Klong Khon, Bangtabun, Ban Laem and Laem Phak Bia. The Inner Gulf of Thailand is one of the most important sites for migratory waterbirds in mainland South-east Asia. Between 150,000 and 300,000 birds are estimated to use the site annually, the majority feeding on the highly productive intertidal mudflats. Over 100 waterbird species have been recorded at the site, including seven species of duck, 50 species of wader and 18 species of tern or gull. Species recorded at the site include 13 globally threatened species, of which at least four are thought to regularly occur in significant numbers: Nordmann's Greenshank Tringa guttifer, Spoon-billed Sandpiper Calidris pygmeus, Greater Spotted Eagle Aquila heliaca and Spot-billed Pelican Pelecanus philippensis. In addition, three globally near-threatened species regularly occur at the site in significant numbers: Asian Dowitcher Limnodromus semipalmatus, Malaysian Plover Charadrius peronii and Painted Stork Mycteria leucocephala. Furthermore, at least 10 waterbird species occur at the site in concentrations higher than 1% of the Asian biogeographic population, underlining the site's international significance.

Non-bird biodiversity: Fish Freshwater Sawfish Pristis microdon (CR)

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 
Spot-billed Pelican Pelecanus philippensis non-breeding  2004  present  A1  Near Threatened 
Greater Spotted Eagle Clanga clanga winter  2004  present  A1  Vulnerable 
Lesser Sandplover Charadrius mongolus winter  2004  present  A4i  Least Concern 
Greater Sandplover Charadrius leschenaultii winter  2004  present  A4i  Least Concern 
Spoon-billed Sandpiper Calidris pygmaea winter  2004  present  A1  Critically Endangered 
Common Redshank Tringa totanus winter  2004  present  A4i  Least Concern 
Asian Dowitcher Limnodromus semipalmatus winter  2004  present  A4i  Near Threatened 
Black-tailed Godwit Limosa limosa winter  2004  present  A4i  Near Threatened 
Spotted Redshank Tringa erythropus winter  2004  present  A4i  Least Concern 
Spotted Greenshank Tringa guttifer winter  2004  present  A1  Endangered 
Long-toed Stint Calidris subminuta winter  2004  present  A4i  Least Concern 
Brown-headed Gull Larus brunnicephalus winter  2004  present  A4i  Least Concern 
Whiskered Tern Chlidonias hybrida winter  2004  present  A4i  Least Concern 
A4iii Species group - waterbirds unknown  2004  20,000 individuals  unknown  A4iii   

IBA Monitoring

2004 high not assessed not assessed
Good - based on reliable and complete / representative data

Biological resource use fishing & harvesting aquatic resources - unintentional effects: large scale happening now majority/most of area/population (50-90%) slow but significant deterioration high
Biological resource use hunting & collecting terrestrial animals - intentional use (species being assessed is the target) happening now some of area/population (10-49%) slow but significant deterioration medium
Human intrusions and disturbance work and other activities happening now some of area/population (10-49%) slow but significant deterioration medium
Natural system modifications other ecosystem modifications happening now some of area/population (10-49%) moderate to rapid deterioration high
Pollution agricultural & forestry effluents - type unknown/unrecorded happening now some of area/population (10-49%) slow but significant deterioration medium

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Don Hoi Lot Wetlands of International Importance (Ramsar) 87,500 protected area contained by site 87,500  


IUCN habitat Habitat detail Extent (% of site)
Artificial - terrestrial   -
Wetlands (inland)   -
Coastline Intertidal mud, sand & salt flats; Shallow marine waters, coral reefs & keys  -

References 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. Erftemeijer, P. L. A. and Jugmonkol, R. (1999) Migratory shorebirds and their habitats in the Inner Gulf of Thailand. Bangkok and Hat Yai: Wetlands International and Bird Conservation Society of Thailand. Wetlands International-Thailand Programme, Publication No.13. Office of Environmental Policy and Planning (1999) Directory of internationally important wetlands in Thailand. Bangkok: Ministry of Science, Technology and Environment. (In Thai.) Round, P .D. (2001) Waterfowl and their habitats in the Gulf of Thailand. Bird Conservation Society of Thailand Bulletin 18(4): 8-16.

Contribute  Please click here to help BirdLife conserve the world's birds - your data for this IBA and others are vital for helping protect the environment.

Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Inner Gulf of Thailand. Downloaded from on 21/10/2016

To provide new information to update this factsheet or to correct any errors, please email BirdLife