Current view: Text account
Site description (2001 baseline):
Site location and context
Lac d’Aleg is situated 5 km to the north-west of the town of Aleg in the south-west of the country. The lake is a closed depression in an old course of the Senegal river fed by rainwater run-off from Oued Katchi, which drains a catchment of 3,420 km². The Katchi is a seasonal watercourse which was formerly a tributary of the Senegal river, but now cut off from it by dunes. The lake is endorheic and semi-permanent and typically varies in depth from 1–2 m at the end of the dry season to a maximum of 3–4 m at the end of the rains. At its maximum size, usually attained in October, it is 22 km long and 4 km wide. The area of the lake varies considerably from year to year depending on rainfall. The vegetetation of the lake forms concentric rings in which the central zone is characterized by
Echinochloa stagnina,
Nymphaea lotus,
N. oleracea,
Ipomoea aquatica and
Aeschynomene pfundii. Nearer the water’s edge
Sesbania rostata,
Ammania senegalensis,
Cynodon dactylon and
Cyperus erectus dominate, while in seasonally inundated areas
Bergia suffructicosa,
Alternanthera sessilisa and
Glinus lotoides are common. The banks are characterized by woody species such as
Balanites aegyptiaca and
Capparis decidua and grasses include
Cenchrus biflorus,
Cyperus conglomeratus and
Dactyloctenium aegyptiacum. The southern edge of the lake is bounded by the Nouakchott–Aleg road. Average annual rainfall is c
.150 mm.
See Box for key species. In addition, there are occasional records of Falco naumanni, Gallinago media, Glareola nordmanni and Acrocephalus paludicola from this site. All are thought to refer to birds on passage, although the status of A. paludicola is hard to establish. More than 116,000 waterbirds were recorded here in September 1987. Merops bulocki, a species of the Sudan–Guinea Savanna biome (A04), has been recorded at this site.
Lake Aleg is of great importance as a passage and wintering area for migratory birds, especially Palaearctic birds.
Non-bird biodiversity: None known to BirdLife International.
In 2023, the annual count gave a total of 44881 individuals.
In 2022, the total number of birds counted was 179038.
In 2021, the total number of birds counted was 41600.
the 2020 annual count gave a total of 73999 individuals divided into 51 species (Natmau count, 2020)
the dominant species are : Anas querquedula 15400 individuals and Cascaded Duck: 23400 individuals
in January 2017,41600 individuals were counted with 24 different species(den Natmau, 2017).
the dominant species are: Anas querquedula( 12500individuals),Plectropterus gambensis(6500 ind), Dendrocygna viduata(6580) and Himantopus himantopus(7550)
20,8734 individuals divided into 28 species were counted in 2011 by the Direction des Aires Protégées et du Littoral(DAPL).
The dominant species are: Plectropterus gambensis(17500 individuals), Dendrocygne viduata(32700 ind), Himantopus himantopus(13600),Anas querquedula(23800 ind), Porphyrio porphyrio(12000), Bubulcus ibis(9800ind) and Dendrocygne bicolor(9300ind).
the local population practices agriculture and fishing.
Pressure/threats to key biodiversity
The soil and vegetation around the lake are heavily affected by traditional flood recession agriculture, mainly sorghum farming, which covers an area of 2,250 ha of the lake's exposed shores. This includes the construction of makeshift fences around the fields, which create obstacles to the wind, causing sand to accumulate. The construction of small dams, notably on the Oued Ketchi, also reduces the volume of water reaching the lake. The Acacia nilotica woodland that once covered much of the uplands around the lake has now been largely cleared. The fringed herbaceous vegetation is heavily overgrazed by large numbers of domestic animals. Unregulated hunting of waterfowl, particularly by an urban elite from Nouakchott, a three-hour drive (240 km) away, is a growing problem.
The Lac d'Aleg project has been operating in the region for several years. It focused on maximizing the potential of the region's natural resources through small-scale village initiatives: wells, dams and dykes, setting up butane gas sales points, agricultural extension services and so on. This program has been replaced by the PARP project. D'aménagement rural en zone pluviale), financed by the European Union. Its activities will focus on supporting micro-projects, small businesses and local cooperatives, equipping and digging wells, building dams and improving roads/access. The impacts of agricultural development and dam construction must be taken into account.
Decreasing water availability
Lack of integrated ecosystem management
With regard to threats, in the vicinity of Lac d'Aleg, reduced rainfall has led to overgrazing and overexploitation of grazing areas and wetlands. This over-exploitation is particularly evident in the near-total exploitation of the Acacia nilotica forest.
The same applies to ground vegetation: the continuous pressure of grazing animals in the area has caused it to disappear completely.
Conservation responses/actions for key biodiversity
-The only strong measure in this area is the annual counting and monitoring of waterbirds carried out by Nature Mauritanie. The aim is to identify trends in waterbird numbers, detect and act on threats at the right time, and monitor the status of key species and their habitats.
It's not a protected area, so it's not protected.
This is an unprotected site
Site access / Land-owner requests
Difficult to access, especially during winter.
Recommended citation
BirdLife International (2024) Important Bird Area factsheet: Lac d'Aleg (Mauritania). Downloaded from
https://datazone.birdlife.org/site/factsheet/lac-daleg-iba-mauritania on 23/12/2024.
