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Location Gambia, North Bank Division
Central coordinates 15o 50.00' West  13o 31.00' North
IBA criteria A4i, A4iii
Area 22,000 ha
Altitude 5 - 40m
Year of IBA assessment 2001

Site description The reserve is situated on the north bank of the Gambia River almost opposite Kiang West National Park (GM007) and extends from the river to the country’s northern border with Senegal. Bao Bolon is a freshwater tributary of the Gambia River that originates 50 km north of the international border and is a permanent watercourse in an otherwise semi-arid region of Senegal. The shallow valley of the bolon is bordered with extensive tall swamps of Cyperus, Scirpus and Andropogon species and a few square kilometres of Phragmites karka. Further from the channel are seasonal fresh/brackish marshes which, during the rains, are a mosaic of shallow pools and low-growing Gramineae and Cyperaceae. To the west of the Bolon are extensive, sparsely vegetated saline mudflats, shallow lakes and inlets of the Gambia River. On raised ground are islands of scrub and open woodland. Further south, within the river’s tidal influence, are open Avicennia mangrove scrub interspersed with mudflats and, on slightly raised ground, meadows of Sesuvium portulacastrum saltmarsh. Within the daily tidal reach of the river is one of the most extensive and intact areas of tall Rhizophora mangrove forest in the country, cut by numerous inlets. Narrow mudflats border the inlets and the river. The reserve also includes a relatively undisturbed area of closed-canopy savanna woodland above a laterite escarpment.

Key Biodiversity See Box for key species. Most of the reserve is not well known ornithologically. The first complete survey, excluding the mangrove forest, was made in February 1998. The reserve is thought to hold more than 20,000 waterbirds regularly between August and December. It is certainly, measured by the number of waterbird species recorded, the most diverse inland wetland in the country. The open wetlands hold large numbers of herons, egrets, pelicans and Palearctic waders and, in addition to those species listed below, are suspected to be an important passage site for Himantopus himantopus, Charadrius hiaticula, Limosa limosa and Tringa nebularia. The site is of national importance for non-breeding congregations of Anhinga rufa, Pelecanus onocrotalus and P. rufescens. Known or suspected breeding species in the Rhizophora mangrove include Gorsachius leuconotus, Podica senegalensis, Scotopelia peli, Apalis flavida and Elminia longicauda. The bolon is a flyway for large waterbirds and raptors. The latter include Falco naumanni, several hundred of which passed through the reserve in a few hours in March 1994. In addition, two species of the Guinea–Congo Forests biome have been recorded; see Table 2.

Non-bird biodiversity: There are occasional records of Trichechus senegalensis (VU).

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Great White Egret Ardea alba winter  1996  800 individuals  A4i  Least Concern 
Egretta garzetta winter  1996  3,000 individuals  A4i  Not Recognised 
Little Stint Calidris minuta winter  1996  12,000 individuals  A4i  Least Concern 
Collared Pratincole Glareola pratincola winter  1996  2,500 individuals  medium  A4i  Least Concern 
Slender-billed Gull Larus genei winter  1996  300 individuals  A4i  Least Concern 
A4iii Species group - waterbirds winter  1996  20,000-49,999 individuals  unknown  A4iii   

IBA Monitoring

2001 high not assessed not assessed
Good - based on reliable and complete / representative data

Agriculture and aquaculture annual & perennial non-timber crops - small-holder farming happening now majority/most of area/population (50-90%) slow but significant deterioration high
Agriculture and aquaculture livestock farming and ranching (includes forest grazing) - small-holder grazing, ranching or farming happening now majority/most of area/population (50-90%) slow but significant deterioration high
Biological resource use gathering terrestrial plants - unintentional effects (species being assessed is not the target) 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

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Baobolon Wetland Reserve Wetlands of International Importance (Ramsar) 20,000 protected area contained by site 20,000  


IUCN habitat Habitat detail Extent (% of site)
Artificial - terrestrial   54%
Wetlands (inland)   25%
Shrubland   17%
Forest   3%

Land use

Land-use Extent (% of site)
agriculture -
hunting -
nature conservation and research -
other -
Notes: Cutting of swamp vegetation for roofing and fencing.

References DPWM (1997, 2000).

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Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Bao Bolon Wetland Reserve. Downloaded from on 22/10/2016

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