PHD-School of Environmental Studies

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This collections contains bibliographic information and abstracts of PHD theses and dissertation in the School of Environmental Studies held in Kenyatta University Library

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Browsing PHD-School of Environmental Studies by Author "Kerich, Richard Kimutai"

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    A comparative study of the influence of variations in environmental factors on phytoplankton roperties of selected reservoirs in Central Kenya.
    (2011-08-03) Kitur, Lesan Esther; Kotut, Kiplagat; Kerich, Richard Kimutai
    Limnological information on reservoirs is important as it forms a vital baseline for among others the detection of undesirable changes in water quality. The physicochemical and phytoplankton properties were investigated in uhuru, Ruiru, Ngewa, Comte and Kianjjibbe reservoirs in central and Nairobi provinces of Kenya, over a period of 12 months (between February 2002 and January 2003) The aim of the study was to determine the nature and level of variation in the physico-chemical properties and its influence on phytoplankton composition, diversity and biomass. Sampling was done during day time and samples analyzed within four hours of sample collection. Among the limnological properties measured were: Secchi depth, temperature, electrical conductivity, dissolved oxygen pH, total alkalinity, nitrite-nitrogen, nitratenitrogen, total nitrogen, ortho-phosphate, total phosphate, soIuble reactive silica, phytoplankton composition and phytoplankton biomass. The study revealed varied degrees of seasonal changes in physico-chemical and phytoplankton properties of the reservoirs. Mean Secchi depth (SD) ranged from 0.1± 0.4 (Ndewa) to 0.9 ± 0.43 m (Ruiru). In general, the highest variation was noted during the dry season. Mean EC ranged from 45.8 ± 5.7 uS cm-1 (Ruiru) to 298.9 ± 41.5 pS cm- in Kianjjibbe with the highest EC being recorded during the dry season. Mean total alkalinity (TA) at the reservoirs ranged from 18.0 ± 0.24 mg L-1(Ruiru) to 110.2 ± 15 ') mg L-1 (Kianjjibbe). Mean nitrate nitrogen (N03-N) concentration ranged from 4.2 ± 043 pg L-' in (Ngewa) to 13.6 ± 1.14 pg L_1 in (Kianjjibbe). Low mean N03-N concciltration was recorded during the dry season. Mean total nitrogen (TN) concentration a the reservoirs ranged from 32.5 ± 28.7 Itg L-1 (Kianjjibbe) to 40.5 ± 36.9 lag L- (Comte). High (TN) concentration was recorded during the wet season. Mean total phosphorous (TP) ranged from 0.70 ± 0.25 pg L-1 (Kianjjibbe) to 1.03 ± 0.82 ug L-1 (Comte). High mean TP concentration was recorded during the wet season. Mean soluble reactive silica (SRS) concentration ranged from 3.2 f 0.47 (Uhuru) to 7.3 f 0.74 pg I ,(Ngewa). High SRS concentration was recorded during the dry season. A significant difference in Secchi depth electrical conductivity, total alkalinity, nitrate nitrogen total nitrogen, total phosphorus and Soluble reactive silica was noted in all the five reservoirs (P<0.001). A total of 35 phytoplankton genera belonging to 7 divisions were 1ccntified in all the five reservoirs. However the largest number of genera (16) belongs d to the Chlorophyta while Cryptophyta had only one genus. Total biomass ranged "rom 3291.87 mg L_1 (Ngewa) to 22,338.763 mg L-1 (Kianjjibbe). Most of the biomass vas due to Dinophyta. Wet season was characterized by high biomass. Total biomass between the reservoirs were significantly different (p<0.001). Phytoplankton biodiversity was high during the dry season. Uhuru reservoir had the highest diversity of 2.4 bits The study concludes that the reservoirs investigated vary in levels of physico-chemi,- 11 and phytoplankton properties investigated. This variation was attributed to differences in rainfall, volume of outflow and use dynamics of the water of the reservoirs.
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    Deforestation and decimation of Biota in Kericho district of Kenya, East Africa
    (2012-06-12) Kerich, Richard Kimutai; Koech, Michael K.; Njuguna, Stephen G.
    Deforestation and decimition of Biota in Kericho District, Kenya. Deforestation and decimation of biota have been recognized as some of the most pressing world problems of the recent times. Today certain plants and animals are faced with a threat of extinction due to increased deforestation and decimation of biota within the natural environment. This study focuses on deforestation and decimation of plants and animals and sought answers to the following questions: a)Is the amount of land under natural forests in Kericho District the same extent now as it was twenty (or more)years* ago? b) What kind of faunal and floral changes have taken place within Kericho District since the last twenty (or over) years* ago? c) Is the productivity of soil the same now as it was twenty (or over)years* ago? and if not why? d) Is there a plant or animal whose existence in the District is endangered outside the protected areas? e) What are the major causes of increased rate of deforestation and decimation of species within the District? *Refers to twenty or over years from 1988. The study was carried out in Kericho District of Kenya, East Africa using fifty (50) randomly selected nodal or study points. The selected study points were scattered throughout the District. From each study points ten (10) interviewees were selected. Interviewees were selected. Consequently the total number of people interviewed were five hundred (500). When all the fifty nodal points are considered. The District was divided into two ecological zones and for each of the zones thirteen (13) plants and thirteen (13) animals were sampled for the study. The information required from the respondents was that which helped in the attainment of the objectives stated. Specifically, four broad areas were dealt with by the stated objectives and these are:- a) Magnitude of deforestation of the past twenty (or over) years ago as compared with the present. b) Relative abundance of named plants and animals. c) Cultural traditions and perception of environmental conservation. d) Environmental awareness and mode/rate of information dissemination. The data required were collected through the use of a questionnaire and an observation record sheet. Field observations were done by the researcher using the observation record sheet as a tool while the questionnaire was used to elicit information from the respondents. When preparing the research tools, the objectives of this study were borne in mind. This was necessary if the set objectives were to be achieved. In summary, the study was intended to: a) determine the extent of deforestation in Kericho District. b) identify the major reasons for deforestation in the District. c) identify the conservation measures taken to safeguard the forests in the District. d) identify those floral and faunal species that are endangered within the District. e) identify major causes of elimination of plant and animal species within the District. f) identify (if any) attitudes and perceptions of the people of the District that would reinforce or go against the conventional conservation measures for soil, natural forests, and endangered plant and animal species. g) determine the state of environmental awareness of the people of Kericho District. The tools were therefore designed so as to meet the requirements of the stated objectives. Majority of the data collected were in form of stated opinions checked off in the provided Likert Scale within the questionnaire. To ease analysis and interpretation of data, responses were categorized depending on their position within the provided Likert Scale. For all the responses received in form of a Likert Scale, categorization was done accordingly. Classification of the opinions expressed made it easy to distinguish between the extreme opinions e.g. "Low" and "High". However, "decision" level was set for all responses given in form of a Likert Scale. In judging the provided responses the set "decisions" level was "moderate". Any response that was either high, or very high was categorized "high" while responses given as very low, low, or moderate were categorized "low". From the recorded opinions, frequency of responses falling into any one category (i.e. low or high) was determined using the set criteria mentioned above. As a basis for conclusion, means, percentages and absolute counts were determined for the various categories of responses received. The other set of data collected was that obtained from field observation and these include actual counts of plants within their natural environment and self assessment of the extent of deforestation within the study areas. Data derived from actual field observation were intended to confirm the information given by the respondents regarding deforestation and decimation of biota. From the assembled data relevant calculations were done depending on the parameters involved in the objective under consideration. Basically, averages, percentages and frequencies were computed and these sufficed for to conclude on set objectives. It was from the computed values that conclusions were made concerning the stated objectives. The research findings indicate that: a) Deforestation in Kericho District is currently higher than it was in the past** according to peoples views. (see table 11p.83). b) Majority of the forests within Kericho District have reduced in size by people's opinions. (see table 12 p.86). c) Due to habitat destruction (in form of deforestation) animals have greatly reduced in number everywhere within the District). d) Within Kericho District, there has been a great reduction in both plants' abundance and their species diversity. e) Cultural traditions and environmental perception of the people of Kericho District are supportive of conservation measures of plants and animals. f) Of the sampled plants Juniperus procera was found to be the least frequent outside the gazetted area and needed protection from wanton destruction. g) Acacia lahai, although still abundant within the District, was found to have experienced the greate