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Location Senegal, Louga,St Louis
Central coordinates 15o 50.00' West  16o 14.00' North
IBA criteria A1, A4i
Area 17,000 ha
Altitude 0 - 20m
Year of IBA assessment 2001

Site description Lac de Guiers, lying in the far north of the country, c.20 km south-west of Richard-Toll, is the only large freshwater lake in Senegal. It lies in the dry valley of the Ferlo river and is fed only by rainfall or by floodwaters coming down the Senegal river and allowed to flow south into the lake through sluices and a canal at Richard-Toll. The lake is 35 km long and 7.5 km wide at its widest point. At high-water it covers an area of nearly 17,000 ha. It is used as a water-supply for Dakar, as well as for local consumption and to supply water for the sugar refinery at Richard-Toll. It is surrounded by Sahel thorn-bush savanna, used for livestock-rearing and ‘walo’ (flood-recession agriculture) and areas of irrigated cultivation, including extensive sugar-cane plantations and rice-fields. There are permanent herb swamps dominated by Phragmites and Typha along parts of the lake shore and scattered acacias and other trees used for roosting and breeding by a wide variety of colonial nesting herons and egrets.

Key Biodiversity See Box for key species. The site is particularly important for breeding colonial waterbirds (mixed colonies of herons, egrets, spoonbills and ibises) and for wintering waterbirds, but it has never been surveyed regularly. Only one comprehensive survey of the whole lake has been carried out, in 1991 (Baillon pers. comm.). Phoenicopterus minor is recorded from the site, with a maximum count of 1,170 in 1991, making this the “largest concentration in Senegal after Djoudj” (Baillon pers. comm.). Prinia fluviatilis was recorded from the site in the 1980s, with no details given except location (Lac de Guiers, 16°25’N 15°45’W) and the interpretation that “it is likely that the entire lake region is inhabited”. One other threatened species, Aythya nyroca, was recorded frequently, but irregularly, wintering in the lake in the 1960s and 1970s, but there are no more recent records. A higher total than that given in the Box for Platalea leucorodia was recorded for the site and “the Ferlo”: 440 birds in 1991. In addition to species listed in the Box, the site provides the most easterly records in Senegal for Phoenicopterus ruber (400 in 1991), Philomachus pugnax is regularly recorded in rice-fields adjacent to the lake and a suspected roost was reported just north of the lake in 1992. A total of 155 Sterna nilotica was recorded for the area including the lake in 1990, together with sites SN001 and SN004 (but the majority of these birds on the lake itself). Five of the 12 species of the Sahel biome (A03) that occur in Senegal have been recorded from this site (see Table 2). Numbers of many species will depend very much, from year to year, on water-levels within the lake and in other large water-bodies in the region. Waterbirds are known to move (both within and between seasons) between several sites within the wider Senegal river delta area, including the Djoudj wetlands (site SN001), the Ndiaël basin (SN002), the River Senegal (SN004) and the Diawling National Park in Mauritania. These movements appear to depend on the relative water-levels as well as other factors and, as part of a wider network of fresh and brackish water-bodies, the lake is likely to be important for certain species.

Non-bird biodiversity: The lake contained a resident population of the mammal Trichechus senegalensis (VU) until the mid-1980s, but this population was isolated from animals in the main Senegal river and appeared to be declining. It is probably now extinct.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Lesser Flamingo Phoeniconaias minor winter  1991  1,170 individuals  A1  Near Threatened 
Glossy Ibis Plegadis falcinellus winter  1984  2,600 individuals  A4i  Least Concern 
Eurasian Spoonbill Platalea leucorodia winter  1986  170 individuals  A4i  Least Concern 
African Spoonbill Platalea alba winter  1986  250 individuals  A4i  Least Concern 
White-winged Tern Chlidonias leucopterus winter  1988  2,700 individuals  A4i  Least Concern 
River Prinia Prinia fluviatilis resident  1998  present  A1  Least Concern 


IUCN habitat Habitat detail Extent (% of site)
Artificial - terrestrial   23%
Wetlands (inland)   56%
Grassland   16%
Forest   1%

Land use

Land-use Extent (% of site)
agriculture -
water management -

References Chappuis et al. (1988), Delaporte and Dubois (1990), Hughes and Hughes (1992), Trolliet et al. (1992).

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Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Lac de Guiers. Downloaded from on 26/10/2016

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