Spatial and temporal variation in community structure of phytoplankton in chebara reservoir-Kenya

River impoundments create reservoirs for many of varying, sizes which serve one or more functions, and change transform lotic aquatic systems to lentic ones, with changes in physical and chemical properties, biotic assemblage and productivity. Chebara reservoir is located at 36o E and 22o S and situated within Elgeyo-Marakwet County. The reservoir was formed as a result of damming the Moiben River to supply water to Eldoret town. A study was conducted on composition and relative abundance of phytoplankton in the reservoir from December 2007 to April 2008. Sampling was done every month at six stations distributed over the reservoir; one station at inlet of Moiben River, one station at the outlet, three at minor inlets and one within the reservoir. Phytoplankton were collected using a 28nm diameter plankton net immersed vertically below the photic depth. Photic depth was measured using 25cm diameter Secchi disk. Phytoplankton were identified and enumerated using a compound microscope. All statistical analyses were performed with STATIGRAPHIC 2.1 Plus and STATISTICA 6.0 procedures. Six phytoplankton classes were identified which included Cyanophyceae (22 genera) Bacillariophycae (25 genera), Chlorophyceae (55 genera), Euglenophyceae (3 genera), Rhodophyceae (2 genera) Pyraphyceae (6 genera) and Crysophyceae (8 genera) similar to observations made in tropical oligotrophic lakes. The order of abundance was Pyraphyceae> Cyanophyceae> Chlorophyceae> Bacillariophyceae> Crysophyceae>Euglenophyceae>Rhodophyceae. Members of the Class Chlorophyceae showed the highest species diversity and abundance. The results obtained from this study can be used track the effects of catchment land use in the drainage basin investigate the cumulative, long term effects of climate change, and river impoundment on the algal evolution. Key words: Spatial and Temporal Variation, Community Phytoplankton, Chebara Reservoi

Effects of physico-chemical parameters on abundance and biomass of phytoplankton in chebara reservoir-Kenya

River impoundment creates reservoirs of varying sizes that supply water for multiple uses including electric power generation, domestic, agriculture or industry. However, damming of rivers creates an aquatic habitat of slow moving water of varying depths and altogether changing the biotic and physico-chemical status of a waterbody. Chebara reservoir was created to supply water to Eldoret Municipality. Chebara reservoir is located at 36 05 E and 0 22 S and situated within Elgeyo-Marakwet County. A study was conducted on the physico-chemical parameters and the abundance and biomass of phytoplankton in Chebara reservoir from December 2007 to April 2008. Stratified sampling was done every month at six stations distributed over the reservoir; one station at inlet, one station at the outlet, one stationat a minor inlet draining through human settlement, one at minor inletdrainingthrough farmland and one within the reservoir. Temperature, pH and ElectricalConductivity were measured in situusing JENWAY® 3405 Electrochemical Analyser. Secchi depth visibility was measured by vertically immersing a 25cm diameter Secchi disk to disappearance. Phytoplankton were collected using a 28 m diameter plankton net immersed vertically below the photic depth. Phytoplankton was identified and enumerated usingSedgwick—Rafter cell underan invertedor microscope, or Olympus®ModelCK2, atamagnificationofX400. Primary production and biomass were determined by chemical analysis of chlorophyll-a concentration and biological oxygen demand (BOD). Nutrientconcentrations were measured spectrophotometrically, while alkalinity was measuredby acidimetric method. Phytoplankton abundance and biomass were related to the physico-chemical conditions of the reservoir. All statistical analyses were performed with STATIGRAPHIC 2.1 Plus and STATISTICA 6.0 procedures. There were no significant differences in the spatial or temporal physico-chemical parameters. The reservoir was homogenously oligotrophic and alkaline with only very slight variations. among dates and samplingstations. The productivity of Chebara reservoir was low (approximately 0.8 µgmillilitre-1) asestimated by chlorophyll a, suggesting oligotrophy. The highest abundance was observed in March and at station 3,while the lowest abundance in April and at station 5. CCA results indicated strong relationships between the various phytoplankton genera and physical and chemical conditions, except for biological oxygen demand which had a weak effect. The study also indicates that phytoplankton growth in the reservoir is more likely to be limited by availability of P than N. The results obtained from this study can be useful for tracking the effects of changing activities in the drainage basin and the tributaries that contribute water directly to the reservoir. Calcium concentrations were consistently low, but the high abundance of pyraphytes in this reservoir could suggest a need to monitor management practices in the reservoir catchment that maintain calcium concentrations and populations of pyraphytes low in order to reduce the water treatment costs. This research further recommends that a research be carried out on macro invertebrates in order to accumulate sufficient knowledge which will be useful for watershed best management practices aimed at ensuring long term protection for water supply. Keywords: Physico-chemical Parameters; Abundance and Biomass; phytoplankton; Chebara reservoi

Extensions of Lefkovitch matrix for modeling invasive Cestrum aurantiacum population Dynamics

Modeling of invasive species using stage based matrix methods can be exploited to understand population dynamics of plants using stage based Leftkovitch matrix models. This study reviewed and extended the stage based matrix incorporating invasion variables of invasive Cestrum aurantiacum across different forest types, ecological zones and altitudes.  The estimation of eigenvalues of the extended stage based Lefkovitch matrix and its corresponding right and left eigenvectors representing stage structure and reproductive value respectively were determined. The results shows the growth rates for Kiptogot λ =4.84 and Kimothon λ =3.21, Suam λ=2.89, Kitale λ =3.91 and Saboti λ=3.58. The  stable  stage  distribution of  individuals  species  in each  of  the  three life  stages  for  Kimothon  forest  block is  84.6% for seedling, 12.9% sapling and 2.5% mature trees while Kiptogot was 88.9% seedling, 9.7% sapling, 1.3% mature trees. Suam block was 82.8% for seedling, 16% sapling, 1.2% mature trees. This study provides various extensions of stage based matrix for estimation and projection of the invasive tree population and information for managing invasive trees species within the forests ecosystems. Keywords: Lefkovitch matrix, growth rate, Stable stage distribution, extension of stage based matrix

Application of Markov Chain Model in Studying progression Of Secondary School Students by Sex During The Free Secondary Education: A Case Study of Kisii Central District

Enrollment forecasting is an essential element in budgeting, resource allocation, and the overall planning for the growth of education sector. This paper demonstrates the use of Markov chain techniques in studying progression of secondary school students from the time of entry/enrollment in form one to graduation after the expected four years in Kenya’s secondary school level of education. The target population included all the secondary school students in Kisii Central District. The model was used to determine the district’s secondary school completion/dropout rate, retention rate and the expected duration of schooling by sex. It was established that completion rates for male students was higher than that of female students and dropout rates for female students was higher than that of male students. In the long run, it was established that the completion and dropout rates were the absorbing rates. Female students had lower expectation of schooling compared to male students in Kisii Central District. The model is only appropriate in making short period projections. Keywords: Absorbing States, Absorbing Markov Chain, Transition Rates, Dropout Rates, Completion Rates, Fundamental Matri

The Medicinal plants and their economic value in Kakamega Forest Ecosystem: A case study of sustainable land/forest project in Western Kenya

Forest Management of ecosystems plays a fundamental role in providing essential goods and services to rural communities. However, there has been a reduction in the natural forest cover due to resource utilization pressure. The pressure on forest resources is catalyzed by the expansion of markets for forest products, agricultural expansion and escalating poverty levels. An upsurge in the number of users of herbal medicine in urban and rural areas has increased the pressure on the forests, while modernization and change in lifestyle have led to the loss of traditional knowledge associated with medicinal plants utilization and conservation. No detailed economic evaluation of medicinal plants has been undertaken and the current illegal, unregulated and unreported exploitation of medicinal plants has led to overexploitation and loss of biodiversity. A better understanding of the abundance, distribution, uses and economic value of medicinal plants is important for the sustainable exploitation and conservation of forests. The study covered four forest blocks of Kakamega, North Nandi, South Nandi and Kibiri to determine plant species diversity, and their distribution in the disturbed and undisturbed areas of the forest; assess knowledge, utilization and economic estimate by willingness to-pay approach of medicinal plants to communities adjacent to the Kakamega Forest. Value chain analysis had been conducted for medicinal plants and forest user groups from Community Forest Association (CFA) had been trained in product development and access market were used in the study. Experimental Plot techniques were also used to gather ecological data on the frequency, density, diversity and distribution of the plants, whereas key informant interviews, focus group discussions and household interviews were utilized to gather information on ethnobotanical knowledge and household socioeconomic data. Thirty-two key species of medicinal plants were identified and used by local people around the Kakamega forest ecosystem. Forty-seven percent (47%) of these were trees, thirty four percent (34%) were shrubs, sixteen percent (16%) were herbs and climbers three percent (3%). Seventy percent (70%) of the medicinal plants were within the forest and thirty percent (30%) were outside the forest. The three most dominant families were Euphorbiaceae, Piperaceae and Fabaceae with leaves as the most common plant part used constituting 31 % (n=26) of the preparations, followed by roots with 20% (n=17),bark with 14% (n=14), fruits with 11 % (n=9), seeds having 11% (n=9), flowers 2% (n=2) and sap 2 % (n=3). The economic benefits generated from the medicinal plants within the forest ecosystem services in the Kakamega-Nandi landscape in terms of direct use value was about KES 601,918,256 (≈USD 5.19 million) per year, while indirect use value was KES 317,288,046 (≈USD 2.74 million) per year. Indigenous knowledge of the medicinal uses of the plants, their commercial aspects and distribution trends in the forest provision of wide scope for understanding relevant market systems may be tapped for decision support in rural health service planning, policy formulation for conserving the forest, tracking and mitigation of climate change impacts

Ojunga(Etiegni)_Impact of a Kraft Pulp and Paper Mill Effl uent on

Phytoplankton and macroinvertebrate assemblages were used to assess the impact of a kraft pulp and paper mill effluent in Kenya, on River Nzoia downstream of the discharge point in relation to changes in water quality during May to June and November 2008 (rainy and dry seasons, respectively). Total phosphorus concentration increased from 0.027 mg·L-1 upstream to 0.04 mg·L-1 downstream. Ammonia nitrogen (NH3-N) concentration was 0.51 mg·L-1 upstream and 0.86 mg·L- 1 downstream. Nitrate concentration stood at 1.18 mg·L-1 upstream compared with the 2.23 mg·L-1 downstream. The pH changed from 4.5 to 5.0 upstream to 5.5 to 6.0 downstream, while DO increased from 6.57 to 7.03 mg·L-1 downstream. The BOD5 (biochemical oxygen demand after five days) values remained almost unchanged from 4.63 mg·L-1 upstream to 4.67 mg·L-1 downstream. Taxon composition of phytoplankton and macroinvertebrates correlated with adverse environmental gradients resulting from the mill’s effluent discharge. Overall, there was a shift in composition and abundance of both phytoplankton and macroinvertebrates, with the downstream site recording high numbers of tolerant taxa (i.e., Microcystis sp. and Chironomus sp.). It was recommended that water quality monitoring with effluents of this nature be done using a combination of chemical analysis and biological indicators such as phytoplankton and macroinvertebrate