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Location Kenya, Rift Valley Province
Central coordinates 36o 21.00' East  0o 46.00' South
IBA criteria A1, A2, A4i, A4iii
Area 23,600 ha
Altitude 1,890 m
Year of IBA assessment 2001

NatureKenya



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.

Key Biodiversity See Box and Table 2 for key species. The woodland north of the lake and around Lake Oloidien provides habitat for Prionops poliolophus, which has been recorded here regularly and is known to nest. Acrocephalus griseldis is a winter visitor and passage migrant, the exact status of which is unknown. The lake itself supports a diverse waterbird community, with more than 80 species regularly recorded during censuses. Mean numbers during 1991–2001 were 19,600 waterbirds. Depending on water levels, it can be a significant site for Fulica cristata (mean 5,050 during 1991–2001), Platalea alba (mean 138 during 1991–2001) and Tachybaptus ruficollis (mean 650 during 1991–2001). Many species of duck and Palearctic waders also occur in numbers; Palearctic duck are especially abundant in November and February. Phoenicopterus minor occurs in small numbers at times, mainly on Oloidien. The lake is known for its high density of Haliaeetus vocifer, which nest in the surrounding Acacia woodland. Regionally threatened species include Podiceps cristatus (most recent Kenyan records are from Oloidien, with seven birds seen in January 1996); Oxyura maccoa (regular on Oloidien, with 170 in January 1994 and January 1997); Anhinga rufa (one recorded on Oloidien in January 1997); Casmerodius albus (regular at Naivasha, which is an important feeding site; 73 counted in January 1997); Ephippiorhynchus senegalensis (2–3 birds usually present); Thalassornis leuconotus (occasional; 12 counted on Oloidien in January 1994); Porzana pusilla (status uncertain); and Rynchops flavirostris (irregular visitor). Since 1995 a large nesting colony of Phalacrocorax carbo has established itself in the fringing Acacia woodland at Lake Oloidien.

Non-bird 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.

Populations of IBA trigger species

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   

IBA Monitoring

2012 high unfavourable low
Habitat
Medium - based upon reliable but incomplete / partially representative data

Agricultural expansion and intensification annual & perennial non-timber crops - agro-industry farming happening now small area/few individuals (<10%) no or imperceptible deterioration low
Energy production and mining renewable energy happening now some of area/population (10-49%) very rapid to severe deterioration high
Human intrusions and disturbance recreational activities happening now small area/few individuals (<10%) no or imperceptible deterioration low
Invasive and other problematic species and genes invasive non-native/alien species/diseases - named species happening now some of area/population (10-49%) no or imperceptible deterioration low
Over-exploitation, persecution and control of species logging & wood harvesting - unintentional effects: subsistence/small scale happening now majority/most of area/population (50-90%) moderate to rapid deterioration high
Pollution agricultural & forestry effluents - type unknown/unrecorded happening now small area/few individuals (<10%) no or imperceptible deterioration low
Pollution domestic & urban waste water - type unknown/unrecorded happening now some of area/population (10-49%) slow but significant deterioration medium
Pollution excess energy - noise pollution happening now small area/few individuals (<10%) slow but significant deterioration low
Residential and commercial development commercial and industrial development happening now small area/few individuals (<10%) no or imperceptible deterioration low
Residential and commercial development housing and urban areas happening now small area/few individuals (<10%) no or imperceptible deterioration low
Residential and commercial development tourism and recreation areas happening now small area/few individuals (<10%) no or imperceptible deterioration low
Transportation and service corridors roads and railroads happening now small area/few individuals (<10%) no or imperceptible deterioration low

Wetlands (inland) Freshwater lakes and pools  0 0 moderate (70-90%) moderate (70-90%) unfavourable

Little/none of site covered (<10%)  A management plan exists but it is out of date or not comprehensive  Some limited conservation initiatives are in place  low 

Protected areas

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.

Name Year formed
Lake Naivasha Nature Club 16

Habitats

IUCN habitat Habitat detail Extent (% of site)
Forest Woodland - monodominant  -
Wetlands (inland) Freshwater lakes and pools  70%

Land use

Land-use Extent (% of site)
fisheries/aquaculture -
agriculture -
tourism/recreation -

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 21/12/2014

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