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Item A review of the impacts of invasive aquatic weeds on the bio- diversity of some tropical water bodies with special reference to Lake Victoria (Kenya)(Biodiversity, 0020-12-30) Aloo, Peninah; Ojwang, William; Omondi, Reuben; Njiru, James Murithi; Oyugi, DalmasAquatic weeds may be defined as troublesome or unsightly plants growing in abundance inaquatic situations where they are not wanted. These plants are either adapted to continuoussupplies of water or are at least tolerant to waterlogged soil conditions for substantial periodsof time. The wide range of adaptation to varying amounts of water, and the impossibility ofsharply distinguishing between aquatic and terrestrial environments, makes it difficult toprecisely define an aquatic plant. The menace of water weeds is reaching alarming proportions in many parts of the world, especially in tropical water bodies where they have led toserious ecological and economic losses. Lake Victoria, Kenya, which is the largest freshwaterbody in the tropics, has undergone serious ecological changes including over-exploitationof its fishery resources, degradation of the catchment area, introduction of exotic fish speciesand invasion by the water hyacinth, Eichhornia crassipes (Mart.) Solms (Pontederiaceae),among others. The presence of the weed in the lake has led to many problems includingblockage of water pumps, reduced fishing activities and increase in water borne diseasessuch as schistosomiasis. Positively, aquatic weeds constitute a free crop of great potentialvalue; they are a highly productive crop that requires no tillage, fertilizer, seed, or cultivation.Moreover, these plants have the potential for exploitation as animal feed, human food, sourceof food to some aquatic organisms, soil additives, fuel production, wastewater treatment,source of raw materials and habitat to many organisms. This paper reviews the effects ofaquatic weeds in aquatic systems with examples from some selected waterbodies and specialreference to Lake Victoria.Item Rethinking pastoralism and African development: A case study of the Horn of Africa(Research Gate, 28-10-2005) Kandagor, Daniel Rotichastoralists in the Horn of Africa have become among the most marginalized and disadvantaged of minority groups. This is due to their wide dispersal, climatic and ecological conditions, state neglect, development plans that have excluded them, seizure of their land, land tenure laws, national borders that restrict their freedom of movement, internal strife and national conflicts. The corollary has been the neglect of gender issues in the pastoralist communities, where custom and religious teachings defining women’s role have been overtaken by rapid modern development. Consequently, the bulk of the land in the Horn of Africa, the pastoralist habitat, lies in the semi-arid and arid zone, home to the largest aggregation of traditional livestock producers in the world, estimated at 15 million people. While there is some non-pastoralist production, the pastoralist contribution is more important economically, providing significant employment and income opportunities seldom shown in official statistics. Traditional livestock production is becoming non-viable through the gradual erosion of access to land and water, as they are turned over to cultivation. This loss has been facilitated by the unwillingness of states to acknowledge and respect pastoralists’ rights to land. Loss of mobility of people and animals has disrupted the process of adjustment that maintains the balance between people, land and livestock. Pastoralist society has been adversely affected by state borders dividing ethnic groups, separating people from their kin, traditional leaders, places of worship, markets, pastures and watering places.Item A review of the changes in phytoplankton community structure and ecology in lake naivasha, kenya(Academic Journals, 1970-01-01) Argwings Owino Omondi, Steve Opiyo Balaka, George Ogendi Mokua, James Onchieku Mokua, Steve Oduor OmondiPhytoplankton community structure plays a vital role in freshwater ecosystems. Besides the provision of dissolved oxygen through photosynthesis, they also form an important diet for several fish and zooplankton species. Plankton are also used as biological indicators of water quality. The objective of this paper is to provide a comprehensive review on the changes in phytoplankton community structure and their ecological functional roles. Phytoplankton are the primary producers in Lake Ecosystem. The diversity, distribution, and abundance of phytoplankton are influenced by both abiotic and biotic factors. Lake Naivasha has undergone drastic ecological changes due to the growth in human population, horticultural and floricultural developments and changes in its fisheries. Lake Naivasha is surrounded by horticultural farms that are greatly influencing its ecosystem health and the major fish species in the lake are of introduced species. These anthropogenic activities together with hydrological changes are expected to play a role in the changes in phytoplankton community structure. Previous investigations indicate that there are more than 143 species of phytoplankton and seasonal shift in phytoplankton dominance overtime between Chlorophyta, Bacillariophyta, and Cyanophyta. Due to various limnological, hydrological, and ecological changes being witnessed in the Lake, there is need for the monitoring of phytoplankton community structure. Such information would be useful in the Lake’s management and conservation.Item My Roots and Their Importance in Understanding Abagusii History(Africa Bib, 1986) Kiriama, Herman O.Using his own family as an example, the author shows how a synthesis of a single family tree can help to understand the general history of a society. The genealogy, which extends from 1638 up to 1983, indicates that by the early years of the 17th century, the Abagusii (descendants of Mogusii) had not yet moved from their cradleland somewhere in northern/southern Uganda. They were part of a large congregation of people who were later to separate and become distinct groups. Within the spell of one century, they had migrated to their present homeland in western Kenya. The author examines how the Abagusii moved from their cradleland and under whose leadership, as well as the relationship between different groups of Abagusii. Bibliogr., ref.Item Generalized characteristics of intense rainfall and peak discharges in Athi basin, Kenya(JSHWR Committee on Editorial and Publication Affairs, 1995) Nyadawa, Maurice O.; Kobatake, Shigeki; Ezaki, KazihiroPresented in this paper is a study clarifying any distinctions or similarities in trends of extreme value statistics of rainfall and discharges recorded at stations sampled all over a basin traversing three distinct climatic zones in Kenya. It is found that in Athi basin, difference in seasonal rainfall pattern affect general characteristics of intense rainfall more significantly than spatial variation of mean annual rainfall. Survey of flood potential of the basin revealed zones which are considered hydrologically homogeneous and heterogeneous cases.Item Estimating Transmission Losses in the Main Channel of River Tana, Kenya(J-Stage, 1997) Nyadawa, Maurice O.; Kobatake, Shigeki; Ezaki, KazuhiroThis study has presented correlation equations thought to define channel loss in River Tana in Kenya. Modified Tank Model is used to transfer runoff information from gaged basins to ungaged ones in the study area. The study has revealed that channel loss has two step functions corresponding to flow rates below 800m3/s and larger values.Item Importance of Indeginous Macrophytes in Control of Water Hyacinth in the Nyanza Gulf of Lake Victoria, Kenya.(Aquadocs, 2000) Omondi, Reuben; Gichuki, JohnObservation of macrophytes dynamics in the Nyanza gulf of Lake Victoria is ongoing since the early 1990s. A checklist of the macrophytes and their distribution in the study area is provided. Occurrence of macrophytes before and after the invasion of water hyacinth is highlighted. The dynamics of water hyacinth, control measures employed for its control and macrophyte succession are also mentioned.Item Management and Ecology of Lake and Reservoir Fisheries | Wiley(Wiley, 2002-02) G.Cowx, IanIn this comprehensive edited book, international experts in fisheries management and ecology review and appraise the status of lake and reservoir fisheries, assessment of fisheries yields, trophic ecology, rehabilitation and conservation, including a special section on African lakes where so much information of huge relevance to fisheries managers is now available . Contributions from around the world. Carefully edited by internationally respected editor. Has been generated from acclaimed HIFI Symposium.Item Effects of Zinc, Lead and Copper Concentration Levels on the Distribution of Macro Invertebrates: A case Study of River Sosian, Eldoret Town, Kenya(journal of the kenya chemical society, 2004-08) Osano, Aloys; L.L., CheruiyotThe relationship between zinc and copper concentration levels and the distribution of benthic macro-invertebrates in river Sosiani, Eldoret has been investigated. Atomic Absorption Spectrophotometry (AAS) and the Dip-net method have established the concentration of zinc and copper and the number of macro-invertebrates respectively. The study showed that the concentration of both copper and zinc were higher than the threshold levels and that the macro-invertebrate species were fewer in the more polluted regions of the river. Thus, zinc and copper concentration levels play a role in the distribution of macro-invertebrates.Item Macrophytes of Lake Victoria and succession after invasion of Water Hyacinth(AQUA DOCS, 2006) Omondi, Reuben; Kusewa, MwendeThe distribution of Lake Victoria macrophytes is described. Succession of macrophytes in the lake became more dramatic and dynamic after invasion of water hyacinth. The weed pushes and smothers other free-floating macrophytes like Pistia stratiotes. It then provides substrates for the emergent Vossia cuspidata, which later reduces its population by competition for light and nutrients. The noxious weed is believed to have led to extinction of Azolla nilotica in the lake.Item Systematics and distribution of zooplankton in Lake Victoria basin, Kenya(AQUA DOCS, 2006-01) Mutune, Masai; Omondi, Reuben; Owili, MonicaZooplankton samples were collected, using a 60µm nansen net, from Lake Victoria and adjacent water bodies with emphasis being placed on the different habitats within the ecosystems. A total of 116 species were identified, 63 rotifers, 24 cladocerans and 29 copepods. A number of these were new records for the zooplankton fauna for the country.Item Groundwater overdraft vulnerability and environmental impact assessment in Arusha(Springer, 2006-07-11) Ong’or, Basil T. I.; Cang, Shu LongA simple approach is proposed for identifying areas vulnerable to groundwater overdraft. The methodology utilizes GIS techniques to analyze and evaluate controlling factors in areas with little data. The proposed methodology was applied in Arusha. Water demand in Arusha Municipality and its environs has increased to about 5.3% annually since 1999. Groundwater levels have declined. The aquifer hydrogeological variables were evaluated for impact to potential groundwater overdraft by overlay and index techniques. The spatial distribution of overdraft vulnerability was discussed. The northwestern part of Arusha is the most vulnerable to overdraft and possible serious environmental impacts. The Loruvani area has the most potential for aquifer development due to its permeability, high recharge rate, massive aquifer thickness and low drawdown.Item A botanical inventory and diversity assessment of Mt. Marsabit forest, a sub-humid montane forest on the arid lands of northern Kenya(Wiley, 2007) Githae, E. W.; Chuah-Petiot, M.; Mworia, J. K.; Odee, D. W.A botanical inventory and diversity of trees, shrubs (≥5 cm diameter at breast height [dbh]), herbs,climbers and lianas was assessed in plots (154) of 20 × 5 m in Mt. Marsabit forest, northern Kenya. Werecorded 52 species of trees and shrubs, twelve species of herbs and six species of climbers and lianas.They belonged to 35 families and 64 genera. Rubiaceae was the richest family with nine species followedby Euphorbiaceae (six), Oleaceae (five), Rutaceae (four), Capparaceae, Labiatae and Leguminosae (threeeach). The rest of the families were represented by one or two species. Rinorea convallarioides (Bak.f.)Eyles ssp. marsabitensis Grey-Wilson (Violaceae), an endemic species, and Drypetes gerrardii Hutch.(Euphorbiaceae), were the two most important species, accounting for more than third of the combinedimportance value. Species diversity indices were 2.735 (Shannon–Wiener), 0.88 (Simpson's) and 0.296(Evenness). There was a strong evidence of disturbance arising from anthropogenic and wildlife foragingactivities. This inventory has affirmed Mt. Marsabit forest as a unique habitat for several endemic, rare,threatened or vulnerable plant species, which should be conserved.Item Environmental impact assessment of risk associated with groundwater overdraft remediation in cone of depression, Jining, China(Springer, 2007-01-12) Ong'or, Basil; Shu, Long-cang; Liu, Pei-GuiIn this paper, a simple scenario and probabilistic approach is used to assess the potential groundwater risk due to proposedoverdraft remedial actions in cone of depression, Jining City, China. Focusing on the concentrations of Chloride ions (Cl−) and total hardness (TH), the impact of artificial recharge and reduced pumping on groundwater quality and quantity is analysedby using the three-dimensional finite difference groundwater flow and transport model, Visual MODFLOW, to simulate groundwaterflow and transport within the study area based on scenarios, and utilizes SURFER software to map risk levels. Although 5,10 or 15% reduced pumping with artificial recharge leads to more decrease in Cl− and TH concentrations than the 25%, less volume increase is achieved for the remediation of land subsidence and other environmentalproblems in the cone of depression. The Cl− concentrations in recovered groundwater are within the desired concentration of 200mg/l; however, TH in some cases are abovethe maximum permissible limit of 500mg/l, with an exceedence probability of about 0.67 for recharge and recharge with reducedpumping at 25%. The presence of fractures and hydrogeological complexity greatly determines impacts of remediation, and the22% reduced pumping with artificial recharge offers an optimum strategy for overdraft remediation in the Jining cone of depression.Item Influences of land use/cover on water quality in the upper and middle reaches of River Njoro, Kenya(Blackwell Publishing Asia Pty Ltd, 2007-04-20) Muchiri, Mucai; Shivoga, William A.; Kibichi, Samuel; Odanga, Jethro; Miller, Scott N.; Baldyga, Tracy J.; Enanga, Eric M.; Gichaba, Maina C.Data from 10 sampling sites along the River Njoro are used to examine the contribution of nutrients from upstream land uses draining each of the sampling sites. The data also are used to assess whether both the proportion of land uses and the size of the subwatersheds account for the variability in water quality in the River Njoro watershed. Geographical Information System analysis was used to determine the spatial distribution of land-cover types and subwatersheds contributing run-off to the sampling sites in the River Njoro. Standard Digital Elevation Model-based routines were used to establish the watershed area contributing run-off to each sampling site. Water and sediment samples were collected for chemical analysis, and the nutrient levels were related to the upstream land-use types and the size of the subwatersheds. The mid-stream portion of the River Njoro (near Egerton University) accounts for the highest nutrient contributions. The percentage contribution is magnified by additions from industrial, human settlements and agricultural land uses around the University. There is a significant decrease in nutrient levels downstream, however, indicating natural purification as the river flows through an area of large-scale farming with intense, well-preserved riparian and in-stream vegetation. Steep slopes of the land upstream of Egerton University enhance erosion and nutrient losses from those subwatersheds. Mixed small-scale agricultural and bare lands contribute over 55% of the phosphorus load to the upper and mid-reaches of the River Njoro. The size of the subwatershed accounts for about 53% of the variability in the soluble phosphorus in the river. The land-use subwatershed proportions are important for characterizing and modelling water quality in the River Njoro watershed. Upland land uses are as important as near-stream land uses. We suggest that conservation of intact riparian corridor along the river and its tributaries contributes significantly to natural purification processes and recovery of the ecological integrity of the River Njoro ecosystemItem Spatial and temporal changes in the distribution of Rastrineobola argentea in Lake Victoria(Taylor & Francis group, 2007-11-26) Tumwebaze, R.; Cowx, I.; Ridgway, S.; Getabu, A.; MacLennan, D. N.Following recent changes in the ecosystem of Lake Victoria resulting from the introduction of Nile perch, Lates niloticus, in the 1960s, there is urgent need for information on which to formulate rational exploitation and management of the fisheries resources. This paper presents information on the biomass and distribution of dagaa, Rastrineobola argentea, the second most important commercial species in Lake Victoria. Data were collected during five acoustic surveys conducted between 1999 and 2001, using a Simrad EY500 echo–integrator with a 120 kHz split–beam transducer. Fish samples were collected using a frame trawl, bottom trawl and pelagic trawl, all lined with 5 mm mesh size netting. The mean total biomass of R. argentea in the lake was 476,902 ± 339,308 t at an average fish density of 7.3 ± 5.4 t km −2 in the sampled area. Potential yield was estimated at 581,584 ± 305,377 t (8.5 ± 4.4 t km −2 ). The majority of the biomass of R. argentea (an average of 68%) was distributed in waters of more than 40 m depth. The biomass of R. argentea increased progressively over the survey period, probably as a result of decreased predation pressure by Nile perch.Item The role of the Yala swamp lakes in the conservation of Lake Victoria region haplochromine cichlids : Evidence from genetic and trophic ecology studies(Wiley, 2008-05-04) Abila, Romulus; Salzburger, Walter; Ndonga, Millicent; Owiti, Dickson; Barluenga, Marta; Meyer, AxelLake Kanyaboli, an isolated satellite lake of Lake Victoria, has been suggested as a potential refugium for haplochromine cichlids that have gone extinct in the main basin of Lake Victoria. Mitochondrial DNA (mtDNA) molecular markers, as well as feeding ecology studies, were employed in this study to re-evaluate the evolutionary and ecological significance of six common Lake Kanyaboli haplochromines. The mtDNA marker revealed high genetic variability within four of the six haplochromine cichlids. Five haplotypes were discerned in Astatoreochromis alluaudi (n = 27), seven in Lipochromis maxillaris (n = 29), five in Astatotilapia nubila (n = 12) and 11 in the endangered Xystichromis phytophagus (n = 205). A haplotype genealogy suggests that Lake Kanyaboli harbours mtDNA haplotypes that could have been lost or not sampled in Lake Victoria, or could have arisen in situ. Lipochromis maxillaris appears to have undergone a recent demographic expansion. The pairwise FSTs indicated that only the comparison between X. phytophagus and A. nubila led to a non-significant FST value. All other comparisons were significant at the 0.01 level, indicating the genetic distinctiveness of the haplochromines in the satellite lake. This could suggest that the lake harbours 'pure' relict populations of the haplochromines and therefore that Lake Kanyaboli can be considered a 'genetic reservoir'. Gut content analysis of the six haplochromine species revealed that eight different food items were consumed. No single species fed exclusively on a single food item, but certain food items contributed higher proportions of the fish diet for each fish species. Resource partitioning therefore could be discerned within this haplochromine community. Thus, Lake Kanyaboli and similar satellite lakes provide an opportunity for conservation of both genetic and trophic diversity threatened by introduction of exotics in the Lake Victoria basin. Lake Kanyaboli should be recognized and conserved as important evolutionary significant units for Lake Victoria region haplochromine species.Item Environmental impact assessment using FORM and groundwater system reliability concept: case study Jining, China(Springer, 2008-08-01) Shu, Long; Liu, Pei-Gui; Ong'or, BasilIn this paper, fist-order reliability method (FORM) is used to evaluate the impacts of uncertainties posed by traditionaldeterministic models on the environment in Jining, China. Because of groundwater contamination in shallow aquifer, and anincrease in water demand, the new wells target the confined aquifer with constant pumping rate of 5,000m3/d. Using Theis equation, the groundwater drawdown is analyzed to determine whether the confined aquifer will be contaminated.Although the piezometric level is higher than the phreatic level by 11.0m, the risk of drawdown is still 19.49% when thepumping rate of 5,000m3/d is maintained for 2years. The deterministic model indicates a drawdown of 8.94m which is lower than the maximum tolerancedrawdown of 11.0m. The sensitivity and uncertainty analysis reveal that the model result is more sensitive to transmissivitythan specific yield, while the reliability analysis offers significant information for the decision makers. This approachexposes and minimizes the risk of undesirable consequences such as groundwater contamination.Item Militianisation of resource conflicts: The case of land-based conflict in the Mount Elgon region of Western Kenya - GSDRC(GSDRC, 2008-10) Robert Romborah SimiyuIn the early 1970s, the government of Kenya set out to implement a land resettlement programme for squatters in the Chepyuk area of Mount Elgon District, intended primarily for the Mosop (Ndorobo) and Soy clans of the district’s ‘autochthonous’ and dominant Sabaot community. From its inception, the programme was derailed by claims and counterclaims of state favouritism and corruption by both clans, leading to a cycle of allocations, annulments and evictions. Th is has engendered discontentment and exacerbated intra-community tensions and confl icts, which took a more violent turn in 2006 aft er the fi nalisation of the land allocation process, during the third phase of the resettlement programme. One of the outcomes of the process required some members of the Soy clan, who had already settled, to vacate their land and others to give up part of their land for subdivision and allocation to other families from the Mosop clan and a section of the Soy clan. However, they mobilised young people to defend their land and resist any evictions, culminating in the formation of a militia group called the Sabaot Land Defence Force (SLDF). It is the activities of this militia that have defi ned the confl ict in Mount Elgon DistrictItem Shimoni Caves Contested Meaning(Africa Bib, 2009) Kiriama, H.In pre-colonial and the early colonial periods, African intangible heritage was managed by local communities using their local unwritten laws; many sacred sites were managed by traditional custodians who used a series of taboos, rituals and restrictions to take care of the sites. This was so because many African societies' religious beliefs were based on the respect for natural spirits and ancestors, belief in the continuing involvement of ancestors in their lives, beliefs in the forces of good and evil that can be manipulated by direct communication with the ancestors and spirits through prayer and sacrifice. Therefore places such as mountains, water springs, rocks, rivers and caves became ''intangible sacred' sites. Though this has to a large measure changed because of the influence of Christianity, Islam or Western education, there are areas, however, where ancestor and spirit worship is still done openly regardless of religious affiliation. Shimoni village on the southern Kenya coast is one such place