|Location||Kenya, Rift Valley Province|
|Central coordinates||36o 21.00' East 0o 46.00' South|
|IBA criteria||A1, A2, A4i, A4iii|
|Year of IBA assessment||2001|
Site description This site lies on the floor of the Rift Valley, 80 km north-west of Nairobi, and consists of a shallow freshwater lake (15,600 ha) and its fringing Acacia woodland (c.7,000 ha). Lake Naivasha is of recent geological origin, and is ringed by extinct or dormant volcanoes, including Mounts Longonot, Ol Karia and Eburu. Naivasha’s water is supplied by the permanent Malewa and Gilgil rivers, which respectively drain the Aberdare mountains (IBA KE001) and the Rift Valley floor to the north, by the seasonal Karati river (also draining from the Aberdares) and from substantial ground-water seepage. The Malewa covers 1,730 km2 of the 2,800 km2 catchment, and contributes 90% of the surface water entering the lake. Naivasha has no surface outlet. It is thought that a combination of underground outflow and sedimentation of salts keeps the lake fresh, unlike other endorheic lakes in the eastern Rift Valley. Naivasha includes three chemically distinct water bodies. The main lake (c.15,000 ha, maximum depth c.8 m) incorporates a partially submerged crater, the Crescent Island lagoon (maximum depth c.18 m), at its eastern end. The lagoon is largely isolated at low water levels. To the south-east, separated by papyrus Cyperus papyrus swamp and an isthmus of Acacia woodland, is the small (c.550 ha), somewhat alkaline Lake Oloidien. Papyrus fringes the main lake’s shore (with scatterings of other sedges and Typha) and cloaks the inlets of the Gilgil and Malewa rivers. There are large floating, wind-driven rafts of the exotic water-hyacinth Eichhornia crassipes, usually concentrated in the south-west sector. Submerged macrophytes (including Potamogeton spp. and Naja pectinata) sometimes occur in large beds, mainly in the shallow eastern part, but these vary greatly in extent. The shores of Crescent Island lagoon are steep and rocky or flat and muddy, while Oloidien has an open, grassy shoreline, with no emergent or floating macrophytes. The lake’s levels fluctuate enormously, and Naivasha has been dry within historic times. The surrounding riparian land is almost all privately owned, much of it now used for intensive horticulture and floriculture using water from the lake. A belt of tall Acacia xanthophloea woodland fringes the lake and extends along the rivers to the north, though portions have been cleared for farming; further from the water this gives way to dry open grassland, Tarchonanthus camphoratus scrub and (on rocky hillsides) Euphorbia forest. Naivasha is the second site listed by Kenya as a Wetland of International Importance under the Ramsar Convention.
|Species||Season||Period||Population estimate||Quality of estimate||IBA Criteria||IUCN Category|
|Little Grebe Tachybaptus ruficollis||winter||1997||1,500 individuals||-||A4i||Least Concern|
|African Spoonbill Platalea alba||winter||1997||412 individuals||-||A4i||Least Concern|
|Red-knobbed Coot Fulica cristata||winter||1991||19,400 individuals||-||A4i||Least Concern|
|Grey-crested Helmet-shrike Prionops poliolophus||resident||1999||present||-||A1, A2||Near Threatened|
|Basra Reed-warbler Acrocephalus griseldis||winter||-||present||-||A1||Endangered|
|A4iii Species group - waterbirds||winter||-||20,000 individuals||unknown||A4iii|
|Protected area||Designation||Area (ha)||Relationship with IBA||Overlap with IBA (ha)|
|Lake Naivasha||Wetlands of International Importance (Ramsar)||30,000||protected area contains site||23,600|
Local conservation groups The local conservation group below is working to support conservation at this IBA.
|Lake Naivasha Nature Club||16|
|IUCN habitat||Habitat detail||Extent (% of site)|
|Forest||Woodland - monodominant||-|
|Wetlands (inland)||Freshwater lakes and pools||70%|
|Land-use||Extent (% of site)|
Other biodiversity The lake supports a large and expanding population of Hippopotamus amphibius (c.300 individuals at present). The snake Bitis worthingtonii, endemic to the central Rift Valley above 1,500 m, is recorded from Naivasha.
References Bennun (1992a, 1993), Bennun and Nasirwa (2000), Burgis and Mavuti (1987), Harper (1984, 1987, 1992), Harper and Mavuti (1996), Harper et al. (1990, 1993, 1995), Henderson and Harper (1992), Higgins (1994), Lewis (1983), Nasirwa (1998), Nasirwa and Bennun (1994, 1995), Nasirwa and Owino (2000), Owino and Nasirwa (2001), Owino et al. (in press), Oyugi and Owino (1998a,b, 1999), Spawls (1978), Tarras-Wahlberg (1986), Tyler (1991), Virani et al. (1997).
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Recommended citation BirdLife International (2014) Important Bird Areas factsheet: Lake Naivasha. Downloaded from http://www.birdlife.org on 28/08/2014
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