BC-Department of Zoological sciences
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Item Human and natural impacts on forests along lower Tana river, Kenya: implications towards conservation and management of endemic primate species and their habitat(Springer Netherlands, 2007) Oguge, N. O.; Moinde-Fockler, N. N.; Karere, G. M.; Otina, D.; Suleman, M. A.Seventy-three forest patches were assessed to determine the effects of human and natural impact on native forests along the Lower Tana River flood plains in Kenya between January and March 2001. Seventeen of these forests were within the Tana River Primate National Reserve (TRPNR) while 56 were outside the protected area. Cultivation and dyke construction had the most devastating human impact, which involved partial or complete forest clearing resulting in further fragmentation of forest patches [Suleman MA, Wahungu GM, Mouria PK, Karere GM, Oguge N, Moinde NN (2001) Tana River primate census and forest evaluation. A report to Kenya Wildlife Services]. Natural impacts were either die back or flooding, which appeared to cause progressive degradation of forest structure and biodiversity. Overall, forest area in the Lower Tana significantly reduced by 34.5% (P < 0.001) over a 21-year period. Forest loss was greater outside the reserve (38%) than inside (29.2%) reiterating the significant role played by this protected area in habitat and species conservation. Continued forest loss increases extinction risks for the endemic primate species the Tana River Red Colobus (Procolobus rufomitratus) and the Crested Mangabey sub-species (Cercocebus galeritus galeritus). Initiation of community conservation programmes outside the reserve and introduction of sustainable micro-economic projects were recommended to enhance sustainable livelihoods and the environment.Item Effects of Climate and Human Activities on the Ecosystem of Lake Baringo, Kenya(Springer Netherlands, 2002) Aloo, P. A.Since the beginning of the last century, the Lake Baringo ecosystem has undergone several ecological changes. Most of the changes are a result of human activities within the catchment basin and changes in climatic conditions. Currently, the most significant limnological feature of the lake is its extreme turbidity with an average secchi disc reading of 9.5 cm. The lake water is brownish and muddy because of considerable siltation resulting from high rates of soil erosion caused by overgrazing by livestock and deforestation of the surrounding hills. Due to increased siltation, the bed of the lake in the open waters is virtually devoid of invertebrate life. Primary production in the open waters is very low as the only phytoplankton present are positively buoyant species such as Microcystis aeruginosa, Melosira granulata and Anabaena carcinalis. The depth of the lake has a significant effect on the transparency of the water (P<0.001), where transparency decrease with depth. Under normal conditions, Lake Baringo has low alkalinity, but with less rain, the lake has become more saline with an average conductivity of 660 μS cm−1 while the pH varies between 8.9 and 10.5. Five species of fish have been reported to occur in Lake Baringo: Oreochromis niloticus (Trewavas, 1983), Protopterus aethiopicus (Heckel, 1851), Glarias gariepinnus (Butchell, 1852), Barbus intermedius (Ruppell, 1836) and Labeo cylindricus (Peters, 1852). Presently, the species composition is dominated by Oreochromis (80.04%), Glarias (9.8%), and Protopterus (7.95%). Barbus rarely appear in the fisherman’s catches while Labeo has almost disappeared from the lake since the damming of the inflowing rivers which interfered with its breeding habits. Moreover statistical analysis has shown a significant relationship between fish yield and lake level changes (P<0.001).