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Location Kenya, Nyanza Province,Western Province
Central coordinates 34o 4.00' East  0o 2.00' North
IBA criteria A1, A3
Area 8,000 ha
Altitude 1,130 - 1,160m
Year of IBA assessment 2001

NatureKenya



Site description This is a complex of wetlands in the delta of the Yala river, on the north-east shore of Lake Victoria. The site has three main components: the Yala swamp itself (currently c.6,500 ha after drainage of the eastern 20%); Lake Kanyaboli in the north-eastern corner, a 3-m deep lake of c.1,000 ha; and Lake Sare, the most southerly of several outlets of the Yala river into Lake Victoria, c.5 m deep and 500 ha in area. Formerly, the Yala river flowed through the eastern swamp (now ‘reclaimed’) into Lake Kanyaboli, then into the main swamp, and finally into Lake Victoria via a small gulf. The Yala flow is now diverted directly into the main swamp, and a silt-clay dike cuts off Lake Kanyaboli, which receives its water from the surrounding catchment and through back-seepage from the swamp. A culvert across the mouth of the Yala, some metres above the level of Lake Victoria, has cut off the gulf on the lake and, through back-flooding, created Lake Sare. Water in the main channels and lakes is well oxygenated, but oxygen levels in the stagnant parts of the swamp are low. The predominant vegetation is papyrus Cyperus papyrus, with Phragmites mauritianus in shallower areas and swamp grasses around the periphery. A thick fringe of papyrus surrounds both Lake Kanyaboli and Lake Sare; in the case of Lake Sare, this merges with the main swamp. The Yala swamp complex is by far the largest papyrus swamp in the Kenyan sector of Lake Victoria, making up more than 90% of the total area of papyrus. The swamp acts as a natural filter for a variety of biocides and other agricultural pollutants from the surrounding catchment, and also effectively removes silt before the water enters Lake Victoria. The site supports an important local fishery for the Luo and Luhya people who live to its south and north, respectively.

Key Biodiversity See Box and Table 3 for key species. Yala swamp supports sizeable populations of Chloropeta gracilirostris (common in tall, undisturbed stands of fringing papyrus, especially at Lake Kanyaboli) and Laniarius mufumbiri. The Near Threatened Gallinago media, a Palearctic migrant, probably also occurs. Because of its size and the generally good condition of the papyrus, the Yala swamp complex is an important site for East Africa’s papyrus endemics. These include Chloropeta gracilirostris, Cisticola carruthersi, Bradypterus carpalis and Serinus koliensis. Many other wetland birds also occur. Reports of occasional sightings of Balaeniceps rex by the local residents have not been confirmed. Regionally threatened species include Casmerodius albus (present in small numbers) and Porzana pusilla (recorded from Lake Kanyaboli, but may not be resident).

Non-bird biodiversity: Lake Kanyaboli is an important refuge for Lake Victoria cichlid fish, many of which have been exterminated in the main lake by the introduction of the non-native predatory fish Lates niloticus. These include economically important species such as Oreochromis esculentus (VU), as well as a number of Haplochromis species. Lates niloticus is present in Lake Sare, which has an impoverished fish fauna compared to Kanyaboli.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Papyrus Gonolek Laniarius mufumbiri resident  1999  present  A1, A3  Near Threatened 
Carruthers's Cisticola Cisticola carruthersi resident  1999  present  A3  Least Concern 
White-winged Scrub-warbler Bradypterus carpalis resident  1999  present  A3  Least Concern 
Papyrus Yellow Warbler Chloropeta gracilirostris resident  1999  present  A1, A3  Vulnerable 
Sharpe's Pied-babbler Turdoides sharpei resident  1999  present  A3  Least Concern 
Red-chested Sunbird Nectarinia erythrocerca resident  1999  present  A3  Least Concern 
Northern Brown-throated Weaver Ploceus castanops resident  1999  present  A3  Least Concern 
Papyrus Canary Serinus koliensis resident  1999  present  A3  Least Concern 

IBA Monitoring

2013 high unfavourable low
Habitat
Unknown

Agricultural expansion and intensification annual & perennial non-timber crops - agro-industry farming happening now majority/most of area/population (50-90%) moderate to rapid deterioration high
Agricultural expansion and intensification annual & perennial non-timber crops - small-holder farming happening now some of area/population (10-49%) slow but significant deterioration medium
Agricultural expansion and intensification marine and freshwater aquaculture - subsistence/artisinal aquaculture happening now some of area/population (10-49%) slow but significant deterioration medium
Climate change and severe weather drought happening now majority/most of area/population (50-90%) no or imperceptible deterioration low
Climate change and severe weather storms and floods happening now some of area/population (10-49%) slow but significant deterioration medium
Natural system modifications fire & fire suppression - increase in fire frequency/intensity happening now some of area/population (10-49%) slow but significant deterioration medium
Over-exploitation, persecution and control of species fishing & harvesting aquatic resources - unintentional effects: subsistence/small scale happening now some of area/population (10-49%) slow but significant deterioration medium
Over-exploitation, persecution and control of species hunting & collecting terrestrial animals - intentional use (species being assessed is the target) happening now some of area/population (10-49%) no or imperceptible deterioration low
Pollution agricultural & forestry effluents - herbicides and pesticides happening now some of area/population (10-49%) slow but significant deterioration medium
Pollution garbage & solid waste happening now small area/few individuals (<10%) no or imperceptible deterioration low
Residential and commercial development commercial and industrial development happening now some of area/population (10-49%) 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

Wetlands (inland)   0 0 moderate (70-90%) moderate (70-90%) unfavourable

Little/none of site covered (<10%)  No management plan exists but the management planning process has begun  Some limited conservation initiatives are in place  low 

Local conservation groups The local conservation groups below are working to support conservation at this IBA.

Name Year formed
Freinds of Yala Swamp 2007
Yala Swamp Community Conservancy Organisation (Yasco) 2008
Ecofinder Kenya 0
Yala swamp environment volunteers. 0

Habitats

IUCN habitat Habitat detail Extent (% of site)
Wetlands (inland) Freshwater lakes and pools; Permanent herbaceous swamps and bogs  100%

Land use

Land-use Extent (% of site)
fisheries/aquaculture -
agriculture -
other -
Notes: large scale cutting of papyrus
water management -

References Bennun (2000), Britton (1978), Mavuti (1992), Nasirwa and Njoroge (1997),

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Recommended citation  BirdLife International (2014) Important Bird Areas factsheet: Yala swamp complex. Downloaded from http://www.birdlife.org on 18/12/2014

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