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Location Ethiopia, Oromiya,Southern Peoples' Region
Central coordinates 36o 50.00' East  4o 43.00' North
IBA criteria A1, A3, A4i, A4iii
Area 112,500 ha
Altitude 520 m
Year of IBA assessment 1996

Ethiopian Wildlife and Natural History Society



Site description Lake Chew Bahir is at the end of the Ethiopian section of the Great Rift Valley. It lies across the border of South Omo Zone of Southern Nation, Nationalities and Peoples’ Region to the west, and the Borena Zone of Oromiya Region to the east. The southern tip of the lake crosses the border into Kenya. The nearest settlement to the lake, Arbore, is in South Omo Zone, over 130 km south-east of the zonal capital Jinka. The Lake lies in a basin primarily composed of the flood-plains of the Gelana Dulei river, itself formed by the confluence of the Segen and Weyto rivers. Chew Bahir basin and the Gelana Dulei and Weyto valleys are flanked on the west by steep, finely dissected, scarps rising to 1,600 m, the result of large-scale faulting. Lake Chew Bahir is subject to substantial changes in area as a result of variations in river discharge. It often dries out, but the lowest part in the north-east is always moist. As there is no outlet, all water entering the lake is lost by evaporation. Over the past century, Chew Bahir has varied from swamp to shallow open water with a maximum depth of 7.5 m and a surface area of up to 2,000 km². The water of Chew Bahir is so highly saline that it cannot be used for either irrigation or domestic purposes. However, to the south-east across the mudflats lie a series of springs: some occur around the base of rock outcrops, but others are isolated on the flats where they support a dense growth of coarse, salt-tolerant sedge. The site supports a range of habitats, including marsh, open water, mudflats, springs, Acacia–Euphorbia bushland, mixed broadleaved scrub with Terminalia spp., scattered Acacia and Acacia scrub. There is a sparse vegetation of salt-tolerant plants throughout the basin. Particularly common is the tall coarse grass, Sporobolus consimilis and the mat-forming Sporobolus spicatus. There are a number of Cyperus species which are also highly salt-tolerant. However, where fresh water enters there are rich swampy areas and pools which are said to have tall Echinochloa spp., other Cyperus spp. and Nymphaea spp. The marshes support a high population of amphibians and snails. The Weyto valley has a very open, dry Acacia savanna, the main trees being A. senegal and A. polyacantha, with A. mellifera forming dense stands along with spiny capparid species and Cadaba rotundifolia. Ground-cover is sparse, comprising a few perennial grasses, some interesting succulents such as Caralluma spp., many opportunistic annuals and some geophytes such as Pancratium tenuifolium which only appears after heavy rain. The Arbore, Tsemay and Hamer peoples inhabit the Weyto valley and Chew Bahir basin. They are basically pastoralists, but grow some crops opportunistically. Access to the freshwater springs in and beside the lake is disputed.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Vulturine Guineafowl Acryllium vulturinum resident  1996  present  A3  Least Concern 
Yellow-necked Francolin Pternistis leucoscepus resident  1996  present  A3  Least Concern 
Lesser Flamingo Phoeniconaias minor non-breeding  1969-1974  20,000-49,999 individuals  medium  A1, A4i  Near Threatened 
African Openbill Anastomus lamelligerus non-breeding  1974  1,000-2,499 individuals  medium  A4i  Least Concern 
Eastern Chanting-goshawk Melierax poliopterus resident  1996  present  A3  Least Concern 
Heuglin's Bustard Neotis heuglinii resident  1996  present  A3  Least Concern 
Buff-crested Bustard Lophotis gindiana resident  1996  present  A3  Least Concern 
Red-bellied Parrot Poicephalus rufiventris resident  1996  present  A3  Least Concern 
White-bellied Go-away-bird Criniferoides leucogaster resident  1996  present  A3  Least Concern 
Sombre Nightjar Caprimulgus fraenatus resident  1996  present  A3  Least Concern 
Donaldson-Smith's Nightjar Caprimulgus donaldsoni resident  1996  present  A3  Least Concern 
Star-spotted Nightjar Caprimulgus stellatus resident  1996  present  A3  Least Concern 
Somali Bee-eater Merops revoilii resident  1996  present  A3  Least Concern 
Abyssinian Scimitarbill Rhinopomastus minor resident  1996  present  A3  Least Concern 
Eastern Yellow-billed Hornbill Tockus flavirostris resident  1996  present  A3  Least Concern 
Von der Decken's Hornbill Tockus deckeni resident  1996  present  A3  Least Concern 
Rosy-patched Bush-shrike Rhodophoneus cruentus resident  1996  present  A3  Least Concern 
Taita Fiscal Lanius dorsalis resident  1996  present  A3  Least Concern 
Pink-breasted Lark Mirafra poecilosterna resident  1996  present  A3  Least Concern 
Chestnut-headed Sparrow-lark Eremopterix signatus resident  1996  present  A3  Least Concern 
Pale Prinia Prinia somalica resident  1996  present  A3  Least Concern 
Grey Wren-warbler Camaroptera simplex resident  1996  present  A3  Least Concern 
Scaly Chatterer Turdoides aylmeri resident  1996  present  A3  Least Concern 
White-rumped Babbler Turdoides leucopygia resident  1996  present  A3  Least Concern 
Shelley's Starling Lamprotornis shelleyi resident  1996  present  A3  Least Concern 
Golden-breasted Starling Cosmopsarus regius resident  1996  present  A3  Least Concern 
Magpie Starling Speculipastor bicolor resident  1996  present  A3  Least Concern 
Brown-tailed Chat Cercomela scotocerca resident  1996  present  A3  Least Concern 
African Grey Flycatcher Bradornis microrhynchus resident  1996  present  A3  Least Concern 
Hunter's Sunbird Nectarinia hunteri resident  1996  present  A3  Least Concern 
Donaldson-Smith's Sparrow-weaver Plocepasser donaldsoni resident  1996  present  A3  Least Concern 
Parrot-billed Sparrow Passer gongonensis resident  1996  present  A3  Least Concern 
White-headed Buffalo-weaver Dinemellia dinemelli resident  1996  present  A3  Least Concern 
Steel-blue Whydah Vidua hypocherina resident  1996  present  A3  Least Concern 
Somali Golden-breasted Bunting Emberiza poliopleura resident  1996  present  A3  Least Concern 
Trachyphonus darnaudii resident  1996  present  A3  Not Recognised 
Black-throated Barbet Tricholaema melanocephala resident  1996  present  A3  Least Concern 
A4iii Species group - waterbirds non-breeding  1969-1974  20,000-49,999 individuals  medium  A4iii   

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Chew Bahir Wildlife Reserve 273,000 protected area contains site 112,500  

Habitats

IUCN habitat Habitat detail Extent (% of site)
Savanna Bushland & thicket - deciduous; Bushland & thicket - evergreen; Wooded grassland  major
Wetlands (inland) Ephemeral pools and wetlands; Geothermal springs; Permanent herbaceous swamps and bogs; Riverine floodplains; Rivers & streams; Saline lakes; Salt marshes; Saltpans  45%
Grassland Grassland - edaphic, dry; Grassland - Semi-desert  54%

Land use

Land-use Extent (% of site)
agriculture -
nature conservation and research -
hunting major
Notes: The Weyto valley and the lower Omo have been important for big-game hunting.

Other biodiversity The plains around the lake support populations of many mammal species including Equus grevyi (EN). The Chew Bahir basin is an important type-locality for a number of species endemic to the arid and semi-arid conditions of the Ethiopian–Kenyan border area.

References Birchall et al. (1975), Bolton (1970), Coppock (1994), Hughes and Hughes (1992), Talling and Wood (1988), Tyler (1975).

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Recommended citation  BirdLife International (2014) Important Bird Areas factsheet: Lake Chew Bahir. Downloaded from http://www.birdlife.org on 31/07/2014

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