Recent ecological changes in of Lake Sare, western Kenya
Masai, D. M.
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Studies on the ecology of Lake Sare (Kenya) were carried out to provide baseline information on the ecological conditions before a major wetland reclamation project was started upstream of the lake. Results indicated that maximum depth had decreased by 0.9 m while Secchi depth readings had decreased by 0.1 m compared to historical values. This implies that the lake was undergoing siltation. pH values had increased from 6.80 to 7.58 reflecting increased primary production. Conductivity had increased from 106 – 137 2 ~kS/cm. NO3- N and PO4-P had significantly increased from 0.8~kg N l-1 and 0.14 ~kg P l-1 to 23.90.8~kg N l-1 and 34.80.8~kg P l-1 respectively while chlorophyll a values reached 34.8 ~kgl-1. The macrophyte environment was dominated by Cyperus papyrus, Eichhornia crassipes, Phragmites australis, Cyperus papyrus, Eichhornia crassipes, Phragmites australis. The invasion of the lake by Eichhornia crassipes is reported here for the first time. The study further observed macrophyte succession where the floating plants Eichhornia crassipes and Pistia stratiotes were gradually giving way to Vossia cuspidata in the Sare lagoon. The phytoplankton community was dominated by Pediastrum sp., Pseudoanabaena, Synedra sp. and Cyclindospermopsis sp. Cyclindospermopsis sp. has the potential to secrete a toxin Cylindropermopsin which can affects the liver and to some extent the kidney. Zooplankton communities encountered were from the Copepoda, Cladocera and Rotifera genera. The fish community was dominated by Lates niloticus and Haplochromine sp which coexist in this ecosystem. Lake Sare is a high priority ecological site for conservation and management of the resources of Lake Victoria basin. It has direct link with Lake Victoria. Fish populations stocked in the Lake Sare are likely to find their way to Lake Victoria. In view of this the lake can be used as a launch site for restocking Lake Victoria with juveniles of endangered fish species.
- Conference Papers