Lac Horo is a semi-permanent wetland located 60 km south-west of the town of Goundam at the northern end of the Inner Delta of the Niger, some 20 km south-west of Lac Télé (site ML004), but not directly connected with it. Under natural conditions the lake retained flood water from the Niger throughout the dry season in years of good rainfall, but otherwise dried out completely by April. Now the lake is separated from the river by a dam and sluice gate through which the flow of water from the river is controlled. The sluice is opened in mid-November to allow flood water to fill the lake and closed again when the desired level is reached. The lake edges support beds of Typha sp. and Polygonum senegalensis and open water is colonized by Nymphaea sp. and Vossia cuspidata.
See Box for key species. In addition, two species of the Sahel biome (A03) have been recorded from this site (see Table 2). Total counts of waterfowl made in nine years during the period 1972–1987 varied between 25,419 (1983) and 127,823 (1985).
Non-bird biodiversity: None known to BirdLife International.
Pressure/threats to key biodiversity
Lac Horo was designated a Wetland of International Importance under the Ramsar Convention in 1987. The cultivation of millet over much of the area around the lake is bound to cause some disturbance to waterbirds and may make the site less attractive to waders, although Philomachus pugnax may prefer this man-modified habitat. In addition, the lake is fished and uncultivated parts of the margins are grazed.