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454 Pyrosequencing-Based Assessment of Bacterial Diversity and Community Structure in Termite Guts, Mounds and Surrounding Soils
(SpringerPlus, 2015) Makonde Huxley M.; Mwirichia Romano; Osiemo Zipporah; Boga Hamadi I.; Klenk Hans-Peter
Termites constitute part of diverse and economically important termite fauna in Africa, but information on gut microbiota and their associated soil microbiome is still inadequate. In this study, we assessed and compared the bacterial diversity and community structure between termites’ gut, their mounds and surrounding soil using the 454 pyrosequencing-based analysis of 16S rRNA gene sequences. A wood-feeder termite (Microcerotermes sp.), three fungus-cultivating termites (Macrotermes michaelseni, Odontotermes sp. and Microtermes sp.), their associated mounds and corresponding savannah soil samples were analyzed. The pH of the gut homogenates and soil physico-chemical properties were determined. The results indicated significant difference in bacterial community composition and structure between the gut and corresponding soil samples. Soil samples (Chao1 index ranged from 1359 to 2619) had higher species richness than gut samples (Chao1 index ranged from 461 to 1527). The bacterial composition and community structure in the gut of Macrotermes michaelseni and Odontotermes sp. were almost identical but different from that of Microtermes and Microcerotermes species, which had unique community structures. The most predominant bacterial phyla in the gut were Bacteroidetes (40–58 %), Spirochaetes (10–70 %), Firmicutes (17–27 %) and Fibrobacteres (13 %) while in the soil samples were Acidobacteria (28–45 %), Actinobacteria (20–40 %) and Proteobacteria (18–24 %). Some termite gut-specific bacterial lineages belonging to the genera Dysgonomonas, Parabacteroides, Paludibacter, Tannerella, Alistipes, BCf9-17 termite group and Termite Treponema cluster were observed. The results not only demonstrated a high level of bacterial diversity in the gut and surrounding soil environments, but also presence of distinct bacterial communities that are yet to be cultivated. Therefore, combined efforts using both culture and culture-independent methods are suggested to comprehensively characterize the bacterial species and their specific roles in these environments.
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.
A Review of Toxic Metals and Hazardous Organics in Wood Treatment Sites and Their Etiological Implications
(Journal of Chemical Reviews, 2022-02-07) Miranji, Edwin K.; Kipkemboi, Pius K.; Kibet, Joshua K.
Increased natural and human activities over the last century have led to excess levels of inorganic and organic pollutants into the environment and natural ecosystems. This review critically examines heavy metal and organic pollutants' role in wood treatment sites and their etiological consequences. These pollutants are not only recalcitrant but also tenacious to degradation under ordinary conditions. Although some heavy metals are essential to human health, they are toxic at elevated concentrations. Heavy metals feature carcinogenic properties and cause serious health risks to live systems and the environment because of their bio-accumulative, non-degenerative, and refractory characteristics. On the other hand, organic pollutants are readily introduced into the ecosystem from irresponsible use of detergents, volatile organic compounds, paints, pesticides, and wood preservatives. During the wood treatment process, various chemicals are used to enhance durability. Nevertheless, the use of wood preservatives such as chromated copper arsenate (CCA) and pentachlorophenol (PCP) potentially induces pollutants considered detrimental to human health and the ecological environment. Remediation of wood treatment sites using phytomanagement strategies and nanotechnologies has been presented in this review. Therefore, some challenges and recommendations for further research and applications are herein presented.
A “win-win” scenario: the use of sustainable land management technologies to improve rural livelihoods and combat desertification in semi-arid lands in Kenya
(South Eastern Kenya University, 2014) Mganga, Kevin Z.; Musimba, Nashon K. R.; Nyariki, Dickson M.; Nyangito, Moses; Mwang’ombe, Agnes W.
Dryland ecosystems support over 2 billion people and are major providers of critical ecosystems goods andservices globally. However, desertification continues to pose a serious threat to the sustainability of the drylandsand livelihoods of communities inhabiting them. The desertification problem is well exemplified in the arid andsemi-arid lands (ASALs) in Kenya which cover approximately 80% of the total land area. This study aimedto 1) determine what agropastoralists attribute to be the causes of desertification in a semi-arid land in Kenya,2) document sustainable land management (SLM) technologies being undertaken to improve livelihoods andcombat desertification, and 3) identify the factors that influence the choice of the sustainable land management(SLM) technologies. Results show that agropastoralists inhabiting the semi-arid lands in southeastern Kenyamainly attribute desertification to the recurrent droughts and low amounts of rainfall. Despite the challengesposed by desertification and climate variability, agropastoralists in the study area are using a combination of SLMtechnologies notably dryland agroforestry using drought tolerant species (indigenous and exotic), grass reseedingusing perennial native and drought tolerant grass species (vegetation reestablishment) and in-situ rainwaterharvesting to improve livelihoods and by extension combat desertification. Interestingly, the choice and adoptionof these SLM technologies is influenced more by the additional benefits the agropastoralists can derive fromthem. Therefore, it is rationale to conclude that success in dryland restoration and combating desertification lies inprograms and technologies that offer a “win-win” scenario to the communities inhabiting the drylands.
Africa Inland Church (AIC) Arguments On Cattle Rustling Wars and Insecurity among The Pokot and Tugen of Kenya
(RSIS International, 2019) Daniel Rotich Kandagor; Charles C Moindi
In Clemens Greiner’s article on “Guns, land andvoters: Cattle rustling and the politics of boundary(re)makingin Northern Kenya”, it is evident that competition for naturalresources in Baringo Plains (Anderson, 2002) is one of themain factors for the protracted conflicts between the Tugenand Pokot communities (Greiner, 2013). Consequently, EmmaElfversson in her conference paper underscores the role ofreligion in conflicts by saying, “The importance of religionand prayers in building support for, and sustaining, peaceshould not be underestimated… ( Elfversson,September,2014.p23).The role of Religion, therefore, in resolving conflictsin society can be discussed both positively and negativelyrespectively. This is true because religion is often depicted asa trigger factor in many conflicts due to the fact that peoplerelate to it as part of their identities (Kellas, 1998:33).Accordingly, in some parts of the world, people from differentreligions live in peace and coexist without any conflict.Therefore, the relationship between religion and conflict is acomplex one, and scholars need to take into considerationmany factors before one can argue that religion is the maincause of conflict and vice verse (Goldstein, 1994:159).
African Journal of Agricultural Research Physiological response of soybean [Glycine max (L) Merrill] to soil moisture stress
(Academic Journals, 2019-03-22) Mwamlima, Louis; Ouma, Josephine; Cheruiyot, Erick
This study was done to determine the effects of varying soil moisture regimes on CO 2 assimilation of soybean [Glycine max (L.) Merrill] in pots under greenhouse conditions during 2017 and 2018 cropping seasons. The experiment was conducted as a Randomized Complete Block Design (RCBD) in a 4 x 6 factorial treatment arrangement and replicated 3 times. Soil moisture regimes (80, 60, 40 and 20% of field capacity) and cultivars (Gazelle, Nyala, EAI 3600, DPSB 8, Hill and DPSB 19) were first and second factors, respectively. Collected data were subjected to Analysis of Variance (ANOVA) using Linear Mixed Model in GENSTAT. Significantly different treatment means were separated using Tukey's test at 0.05 significance level. Leaf relative water content, stomata conductance, photosynthesis rate and sub-stomatal CO 2 concentrations significantly (P < 0.001) declined with increasing soil moisture stress. Total leaf chlorophyll content increased (P < 0.001) with increased soil moisture stress. Cultivars DPSB 19 and DPSB 8 had relatively higher leaf relative water content and stomata conductance at reduced soil moisture regime at 20% moisture from field capacity indicating moisture stress tolerance potential of the cultivars.
Aluminum tolerance mechanisms in Kenyan maize germplasm are independent from the citrate transporter ZmMATE1
(Scientific reports, 2020) Matonyei, Thomas K.; Barros, Beatriz A.; Guimaraes, Roberta G. N.; Ouma, Evans O.; Cheprot, Reuben K.; Apolinário, Leandro C.; Ligeyo, Dickson O.; Costa, Marcella B. R.; Were, Beatrice A.; Kisinyo, Peter O.; Onkware, Augustino O.; Noda, RobertoW.; Gudu, Samuel O.; Magalhaes, JurandirV.; Guimaraes, Claudia T.
Aluminum (Al) toxicity on acid soils adversely affects maize yields, which can be overcome by combining soil amendments with genetic tolerance. In maize, ZmMATE1 confers Al tolerance via Al-activated citrate release, whereby citrate forms non-toxic complexes with Al3+ in the rhizosphere. Here, we investigated Al tolerance mechanisms in maize germplasm originated from Kenya based on quantitative trait loci (QTL) mapping. Five QTLs and four epistatic interactions explained ~51% of the phenotypic variation for Al tolerance. The lack of Al tolerance QTL on chromosome 6 and the much lower expression of ZmMATE1 in both Kenyan lines than in Cateto Al237, which donates the superior allele of ZmMATE1, strongly indicate that this gene does not play a significant role in Al tolerance in neither parent. In turn, maize homologs to genes previously implicated in Al tolerance in other species, ZmNrat1, ZmMATE3, ZmWRKY and ZmART1, co-localized with Al tolerance QTL and were more highly expressed in the parent that donate favorable QTL alleles. However, these candidate genes will require further studies for functional validation on maize Al tolerance. The existence of Al tolerance mechanisms independent from ZmMATE1 suggests it is possible to develop highly Al tolerant cultivars by pyramiding complementary Al tolerance genes in maize.
AN ECONOMIC ANALYSIS OF TRAFFIC CONGESTION AND EFFECTIVENESS OF DECONGESTION MEASURES IN NAIROBI, KENYA
(University of Eldoret, 2014) Nzai, Charles Chama
Traffic congestion is a wasteful phenomenon to businesses, society, environment and the economy as a whole. Its effects include delayed travel times, reduced productivity and business opportunities, accidents, frustrations, stress and pollution. This study analyzed the economic impacts of traffic congestion and effectiveness of different decongestion measures in Nairobi city, Kenya. Identification of study variables relied on theories and principles from welfare economics, congestion management; stakeholder participation; measuring impacts of traffic congestion; and, Contingent Valuation Method (CVM). Data was collected through questionnaires administered to the city’s motorists, interviews with key informants, observations and secondary data sources. Descriptive statistics, mathematical computations and counterfactual analysis were used to analyze the data. Regression analysis was used to model the relationship between motorists’ Willingness-to-Pay (WTP) for traffic decongestion program and their socio-economic characteristics. Results showed that the city’s congestion is due to continuously increasing number of vehicles without effective corresponding long-term congestion management strategies. Its related wastages were estimated as Ksh 146.5 billion and Ksh 16.7 billion annually in terms of delays and wasted fuel respectively. CVM results showed an average monthly motorists’ WTP of Ksh 1387 totaling to Ksh 8.3 billion annually interpreted as the total value of some benefits of reducing congestion in the city. Regression results also showed that motorists’ income, cost of running cars, price of cars and their perceptions on Government’s role in infrastructural projects were statistically significant at 5% in explaining their WTP bids. Bypass roads were found to minimally have a 7.5% impact in curbing congestion. The expansion of Thika Road and Syokimau commuter train service was estimated to have saved motorists Ksh 80 billion and Ksh 117.03 billion annually, respectively in terms of delays and wasted fuel. Phasing out of 14-seater PSV per se is ineffective in alleviating congestion and has potential of crippling the city’s public transport. With an effective payment machinery, the WTP values show the potential of funding the expensive decongestion programs using Nairobi city’s own resources. Decongestion programs should entail amongst others redesigning of the city’s land use policy in relation to congestion management strategies and parking management policy; introduction of congestion pricing schemes; development of new and modification of road infrastructure; encouraging use of public transport through introduction of consultative BRT systems; improving traffic operations; and, establishing a single agency that shall manage and coordinate efforts on the problem instead of relying on numerous government institutions with disjointed roles. There is need to cascade such research in other growing towns within the county to share experiences and develop national statistics on the problem.
An Examination of the Nature of Sand Harvesting Conflicts and their Influence on Poverty Alleviation Initiatives in Makueni County, Kenya
(IISTE, 2015) Muthomi, Simon; Okoth, Pontian; Were, Edmond; Vundi, Silvia
Though natural resources play an important role in the economies of many countries, conflicts associated with their access continue to contribute to poverty in many African countries. While studies confirm conflict-poverty nexus for high value natural resources, scanty information is available on the low value resources. This study, therefore, examined one such low value resource – sand. The objective was to examine the nature of sand harvesting conflicts and their influence on poverty alleviation initiatives in Makueni County. The study employed descriptive and historical designs. The study was guided by the Resource Curse and Poverty Theories. The study sample comprised of 420 sand harvesters and several key informants. Data collection was done using questionnaires, interviews, focus group discussions and observation. Presentation of data was done using both quantitative and qualitative approaches. The study findings established that sand harvesting in Makueni County has been linked to violent conflicts which left many people either maimed, killed or without their property. These had increased poverty levels in the County. The study therefore recommends for establishment of appropriate institutions to mitigate on the conflicts in order to ensure that sand harvesting provides contributes to poverty alleviation in Makueni County.
Analysis of Temporal Drought Characteristic Using SPI Drought Index Based on Rainfall Data in Laikipia West Sub-County, Kenya
(Scientific Research, 2017-01-01) Karanja, Amon; Ondimu, Kennedy; Recha, Charles
Severe drought has affected Kenya in the past decades reducing crop yields leaving millions of people in dire need of food. Drought cycle in Kenya has reduced increasing drought frequency in the recent decades. This study assessed drought characteristics in Laikipia West sub-County which lies in a region classified as arid and semi arid. The specific objective of the study was to analyze seasonal and annual drought characteristics in Laikipia West sub-County between 1984 and 2014. The study adopted documentary review design in the data collection. Standard Precipitation Index was used during the data analysis process. The drought years identified in Laikipia West sub-County were: 1984, 1985, 1987, 1991, 1995, 1999, 2000, 2005, 2008 and 2009. The seasonal drought events shows that for the period under study Laikipia West sub-County has never experience drought during the MAM and OND seasons in the same year. This explains the importance of seasonal climate forecast to crop farmers. The study also established that the average drought cycle in the study area is 3 years. The study recommends construction of mega water reservoirs which could collect water during the wet season to be utilized during the dry seasons. The study also recommends channeling of drought information through the government agencies at the beginning of every season.
Analysis of the Spatial Relationship between Cattle and Wild Ungulates across Different Land-Use Systems in a Tropical Savanna Landscape
(2018-02-04) Kinga, Geoffrey W.; Mironga, John; Odadi, Wilfred O.
In many African savanna landscapes, domestic and wild herbivores cooccur across different land-use systems, but the role of land-use in shaping their spatial relationship is poorly understood. We evaluated the spatial relationship between cattle and wild herbivores categorized by body sizes and feeding habits across different land-use types, namely, private ranches (PR), transitional lands (TRL), and pastoral grazing areas (PGA), in Laikipia County, Kenya. Cattle and wild herbivores spatial distribution data were obtained from Kenya’s Department of Resources Survey and Remote Sensing (DRSRS). Spatial relationships between cattle and different wild herbivore guilds were analyzed using Ripley’s bivariate function. In PR, wild herbivore guilds showed significant attraction to cattle at short distances. In TRL, wild grazers, mixed feeders, megaherbivores, and medium-sized ungulates exhibited significant attraction to cattle. Additionally, repulsion was observed between cattle and browsers at short distances under this land-use system. In PGA, wild grazers, mixed feeders, and megaherbivores repelled strongly with cattle at short distances while browsers and medium-sized ungulates were significantly attracted to cattle. Cattle and wild herbivores were more randomly and independently distributed in PR than in TRL and PGA. These spatial relationships imply better coexistence between cattle and wild herbivores in PR than in TRL and PGA.
Assesment Of The Concentration Of Selected Heavy Metals (Pb, Cu, Cd, Zn) In Soils Within The Nyambera Dumpsite
(Research Gate, 2020-06-26) Okemwa, Evans; Obed, Nyabaro; Kituyi, John; Mukenyi, Peter
Heavy metals are part of the soil, but at high concentration levels are considered toxic. With the current exponential population growth, urbanization, industrialization and advancement in agriculture has increased solid waste significantly over time. Due to lack of proper well-structured waste management systems, solid waste has been disposed in open dumpsite which lack any mechanism of control. Over time, due to accumulation-various heavy metals are introduced in the soils and end up being leached, carried away by surface-runoff or introduced to plants by farmers who rely on refuse (from the dumpsite) to plant their crops. This study was aimed at determining the concentration levels of Pb, Cu, Cd and Zn at the Nyambera dumpsite and compare their levels with the WHO recommendation levels for soils. Stratified random sampling was employed and soil samples collected on top of the dumpsites, the slope of the dumpsite and at the banks of river Nyakomisaro which flows adjacent to the dumpsite. Digestion was carried using concentrated hydrochloric acid then topped up to 100ml. Metal analysis was carried out using ICPOES. The results of Pb, Cu, Cd and Zn were as follows 91.31, 281.8, 3.253 and 542.3 ppm respectively. The concentrations were found to be very high at the dumpsite as compared to the recommended levels by WHO. Based on the results obtained the dumpsite should be treated with various remediation methods being applied to help lower the levels of these metals. Farmers using the refuse as manure for their crops should seek other alternatives for their farms.
Assessing the impact of farming systems and land use change on dryland plant biodiversity: a case study of Mwala and Yatta sub counties in Machakos county, Kenya
(International Journal of Environment, Agriculture and Biotechnology, 2019-09) Mutua, U. M.; Kisangau, Daniel P.; Musimba, N.
The study focused on assessing the impact of farming systems and land use change on dryland biodiversityand documented the views, knowledge and practice of the farmers on the role of biodiversity in the semi-arid midlandsof Eastern Kenya. A descriptive survey design was employed to collect data on famers’ views, knowledge andpractices from 120 respondents from four locations in Mwala and Yatta Sub Counties in Machakos County. NestedQuadrat method was employed to determine levels of loss of plant live forms in the cultivated and uncultivated areasin the four locations. The collected data was then analyzed using simple descriptive statistical such as percentages,frequency and means. Other methods used in the analysis included Logistic regression, Pearson Chi-square andt-tests. The study established that Households in the study areas understand the benefits of non-crop tree species(100%) and therefore grow the tree species (72%) and also conserve the indigenous species (88%). Results frommultivariate logistic regression analysis further showed that the age and level of education of the respondents werethe strongest statistically significant factors affecting the farmers’ knowledge on above ground biodiversity and itsrelevance to crop production (p < 0.005). It was also established that mixed farming system was the main farmingsystem practiced by 98% of the households in Mwala and Yatta sub counties, with crops and livestock on the samefarm. It was established that average population of plant live forms (grass, shrubs and trees) in the study sites wasfound to be significantly different between cultivated and uncultivated zones in the four locations (p <0.005). It isconcluded that human activities such as farming increases loss of plant live forms and interferes with above groundbiodiversity and reduces the effectiveness of crop-livestock integration in the production systems due to reducedgrazing areas.
ASSESSMENT OF ECOSYSTEM SERVICES IN REHABILITATED LIMESTONE QUARRIES OF BAMBURI, MOMBASA COUNTY - KENYA
(Pwan University, 2021-12-21) Musando, Albert Akondo
Bamburi quarries are expansive areas exploited by the Bamburi Cement Company, the largest cement producer in Kenya. These areas undergo ecological restoration, a process that began in 1971 to mitigate the degradation caused through mining. This study sought to elucidate ecosystem services in the rehabilitated site and to demonstrate how restored quarries can provide sustainable services. Random walks were conducted during this study to establish quarry status before and after rehabilitation. Habitats were mapped, biodiversity surveys conducted, and Simpson Diversity Index (D) calculated to provide a measure of community structure for describing the ecosystems. Additionally, land use activities were identified to determine sustainability of the ecosystems services. Results show that over 566.2 hectares are under various land use activities in Bamburi with over 320 hectares (56.51%) of quarry having been ecologically rehabilitated to achieve a soil pH of 7.2 to 7.53 useful for supporting plant growth. About 7.8% of the study site comprised of grasslands and over 2.8% aquatic habitats. Fourteen (14) species of aquatic plants used in water purification were identified. Four hundred and thirty (430) vegetation species support the ecosystem of which 84 species are listed in IUCN data list as endangered, near threatened and critically endangered. Results from Simpson Diversity Index shows diversity of animals (D) = 0.818. The emergent ecosystem delivers provisioning, supporting, regulating and cultural ecosystem services which include fuelwood, herbal medicine, nutrient cycling, soil formation, erosion control, air and water purification, ecotourism, recreation, as well as education. The site attracts over 181,000 visitors annually. Findings from this study can be applied in policy development to promote restoration of quarries for sustainable ecosystem services.
ASSESSMENT OF EFFECTS OF LAND USE PRACTICES ON RIVER CATCHMENTS A CASE STUDY OF NYONGORES RIVER CATCHMENT
(University of Eldoret, 2016) Langat, Wesley Kiprotich
Nyongores River is one of the major tributaries of Mara River and is located at the upper catchment of Mara River Basin. Over the years, rising population pressure and intensification of agriculture in the catchment has led to; reduced vegetation cover, poor land use management practices and increased soil erosion. The river is currently one of the major contributors of sediment and agrochemicals in the Mara River and Lake Victoria. The goal of the study was to assess the effects of land use and management practices on sediment concentrations in rivers. The specific objectives were: to map land use types, determine sediment delivery rates from land use types, determine sediment load from the main tributaries and assess the existing land use management practices for soil conservation. GIS mapping, water sampling and interviews of farmers from the catchment were carried out in the month of December 2009, January, February and March 2010. The study revealed that 43.2% of the catchment land use was under maize, 33.6% grasslands, 16.1% tea cover, 4.9% forest cover and 2.2% bare land. Land use under maize cultivation contributed the highest sediment concentration of 0.26g/l, forest (0.024g/l) and tea cultivation contributed the least concentration of 0.0351g/l. Among the tributaries of Nyongores River, Chepkositonik River delivered the highest sediment of 0.493 g/l followed by Kagawet with 0.324 g/l, then Ainopng'etunyek with 0.255 g/l while Kiprurugit was the least with 0.198g/l. The study estimated sediment flow into Nyongores River from the four tributaries at about 0.559Kg/s. The study established that the land use management practices for soil conservation within the catchment were; contour ploughing (24%), terraces (20%), agroforestry (17%), planting of trees (17%), intercropping (12%), mulching (6%), gabions (3%) and sand bags (1%). The study has demonstrated that there exists relationship between land use and sediment delivery rates in the tributaries. The study also shows that various land use management practices influences the rates of sediment concentrations in the rivers. Hence, recommends the adoption of integrated river catchment management for sustainable environment and agriculture.
ASSESSMENT OF LAND TENURE, LAND USE AND LAND COVER CHANGES IN TAITA HILLS FOREST FRAGMENTS: A CASE STUDY OF NGERENYI FOREST FRAGMENTS IN TAITA TAVETA COUNTY, KENYA
(Pwani University, 2020-01-23) Mkuzi, Hamisi Tsama
The indigenous Taita Hills cloud forest is fragmented to 5ha or less forest cover, except Chawia, Ngangao, and Mbololo forests which are fragments of more than 5ha. This fragmentation due to changing land uses, threatens the forest biodiversity and land cover. The study assessed the land tenure characteristics and the land use and land cover (LU&LC) changes in Taita hills forest fragments of Ngerenyi area over the past three decades (1987 up to 2017). The specific objectives of the study included establishing the land tenure system in Ngerenyi area, determining the drivers of change in land tenure, land use and land cover, and establishing land use and land cover change in the study area. Questionnaires administered by the researcher were used to generate data on the type of land tenure systems and the drivers of change in land use and land cover changes. Land use and land cover changes were obtained by analyzing multispectral satellite data obtained from Landsat 4-5 1987 and 2008, Landsat 7 1999, and Landsat 8 2017 using Arc GIS software. Supervised classification was applied to detect land use and land cover while change detection analysis was carried to quantify land use and land cover changes. The main land tenure system is freehold land ownership with land use and land cover changes driven by both natural and human induced factors, including agricultural expansion and drought. The study shows both an increase and decrease in the different land use and land cover classes with significant shifts from one class to another. Agricultural and dense vegetation land use and land cover have since been converted to built-up surfaces and light vegetation by 17 percent and 7 percent respectively. An average annual positive change of built-up surfaces of 0.6 percent and 0.2 percent average annual positive change in light vegetation. Agricultural land use and dense vegetation declined significantly by 4 percent and 20 percent respectively between 1987 to 2017. The land tenure has remained the same, however, the land use and land cover have changed over the time period in Ngerenyi area depicting the fragile nature of the Taita Hills forest fragments. The study recommends for education and awareness on the ecological relevance of the forest cover and further studies toxivbe carried out to establish the impacts of the land use and land cover changes on the ecology of the Taita Hills forest fragments in Ngerenyi area
Assessment of land use and land cover change in Makueni County for selected time periods
(South Eastern Kenya University, 2017-03-27) Kebenei, Mercy C.
The surface of the earth is undergoing rapid land use and land cover changes (LULCC) due to various socio-economic activities and natural phenomena. The main aim of this study was to gain a quantitative understanding of LULCC in Makueni County between 2000 and 2016, and analyze the relationship between these changes and their possible underlying drivers in the County. ArcGIS 10.3.1 and ERDAS IMAGINE 2014 were used for the digital image processing and GIS analyses. Image pre-processing and enhancement were done to prepare the images for classification. Supervised classification technique was used to sort and define spectral signatures in the imagery for different land use and land cover (LULC) classes that were identified. Ground truthing was done so as to check the precision of the classified LULC maps. Change detection analysis was performed to assess the class- to- class conversions and change in areal coverage between identified LULC classes between time intervals under study. Accuracy assessment was performed to determine overall, producer’s and user’s classification accuracies. The study area was defined to have seven LULC categories, which were: Built up areas, water bodies, croplands, evergreen forests, bushlands, grasslands and barelands. The results revealed both increase and decrease in the areas of the LULC classes from 2000 through to 2016. Evergreen forest decreased from 3105.8 km2 in 2000 to 1373.0 km2 in 2016 while built up areas increased from 160.7 km2 in 2000 to 644.5 km2 in 2016. Possible drivers of the observed changes ranged from climatic factors such as rainfall and drought to socio-economic factors. Since the results reveal that LULCC has occurred in Makueni County, the study recommends that consistent LULC mapping should be carried out in order to establish trends that will enable resource managers to project realistic change scenarios helpful for natural resource management.
Assessment of land use/land covers changes linked to oil and gas exploration: Developments under changing climatic conditions in Lokichar Basin, Turkana County
(2020) Kariuki, David Mugendi; Mireri, Caleb; Kibwage, Jacob; Oyoo, Daniel
Understanding land use/land cover changes(LU/LC) linked to oil and gas exploration under changing climatic conditions in South Lokichar Basin is crucial.This knowledge will inform policy makers on appropriate sustainable vegetation cover management strategies for the sake of pastrolism practiced in the area.The LU/LC changes were assessed using multi-spatial and multi-temporal remotely sensed imageries acquired through Landsat 5TM and Landsat 8OLI/TIRS by use of ArcGIS.The study assessed medium resolution spatial imageries acquired for the area in both rainy and dry seasons,before oil and gas exploration developments begun in South Lokichar Basin between 2006-2011 and after commencement between 2012-2017.The study established that the average area in hectares under vegetation cover had declined since oil and gas exploration developments begun.A one sample t-test statistics indicated that the area under forest,shrubland and grassland cover had significantly reduced at 90% confidence interval with a p-value of 0.072,0.074 and 0.061 respectively.The study established a decline in NDVI from 1 to 0.433 for the rainy season and 0.411 to 0.122 for the dry season between 2006 and 2017 with a p-value of 0.009 <0.05 on paired t-test implying a significant change on vegetation cover.Sustainable management of vegetation cover is important to safeguard livestock forage.
Assessment of levels of natural radioactivity in surface soils around titanium mines in Kenya
(Kenyatta University, 2011) Masore, Kefa Osoro
All human beings are exposed to radiation from naturally occurring radionuclides in soil and other environmental materials. Some of these exposures are not amenable to control and they are usually referred to as background radiation. Some work activities such as conventional mining inadvertently produce large quantities of naturally occurring radionuclides, which can result in additional and/or elevated levels of radiation exposure of people in the areas around the mining sites. Such exposures - induced or enhanced by human activities - are subject to control by regulatory authorities. In some instances there may be contributions from the two types of exposures and they must be separated before applying regulatory control. In this study, natural radioactivity levels in surface soils around the proposed titanium mines in Kwale district were determined from measurements of 78 samples of surface soils randomly sampled from two villages within the proposed mining area by using a hyper pure germanium (HpGe) gamma-ray spectrometer. The values of radioactivity concentrations in the soils and the likely radiation doses from contact with these soils were determined and are reported in this thesis. The radiological implication of these levels is discussed with regards to the impending mining operations in the area. The ranges and mean of radioactivity concentrations (Bgkg-l) obtained are. 8.4±0.4-43.6±1.5 (_27.6±1.7) for 232Th; 7.4±0.6-40.6±1.4 .(20.9±1.5) for 226Ra and 31.9±1.3-114.1±1.4 (69.5±3.2) for 40K, respectively. The likely absorbed dose rates in air above these soils were calculated from these radioactivity concentrations and found to be 8.5±0.5-36.9±1.1 nGyh-1 with a mean of 25.2±1.4 nGyh-1. The corresponding effective dose rates are 21.0±1.2-90.8±2.6 mSvy--1 with a mean of 62.0±3.5 uSvy--1, which are lower than the global average of 0.46 mSvy 1 and therefore of little radiological risk to the environment of the study subject.
Assessment of polycyclic aromatic hydrocarbons (PAHs) in air and soil from selected sites in Nairobi
(University of Nairobi, Kenya, 2010-07) Situma, Dorice S.
This study was undertaken to investigate the occurrence, spatial distribution and temporal and seasonal variations of sixteen Polycyclic Aromatic Hydrocarbons (PAHs) in Industrial Area, Dandora Municipal dump site and Kabete sites on a monthly basis from February to July 2008. The sixteen PAHs have been identified by various Regional and International Agencies as priority compounds due to their toxicity, potential for human exposure and adverse effects on human health and the environment. Identification and quantification of the P AHs in air and soils was done using a Varian CP 3800 gas chromatograph equipped with a flame ionisation detector. Confirmatory analysis was conducted using Gas Chromatography equipped with a mass spectrometer (HP 6890-HP 5972). Compound detection limits ranged between 0.0165 ng/ filter for acenaphthene and 0.117 ng/filter for anthracene. Levels of P AHs in air were lower at the Kabete site than in Dandora and Industrial Area. The concentrations of individual P AHs in air ranged from below detection level to 3939.66 ±10.28 ng/filter. The sum of the concentrations of the compounds (2.:16 PAHs) ranged from 1704.05 ±191.16 ng/filter to 1881.81 ±202.86 ng/filter in Kabete; 6470.27 ±724.42 ng/filter to 8726.93 ±716.53 ng/filter in Dandora; and between 5853.69 ±631.28 ng/filter and 7822.87 ±851.89 ng/filter in Industrial Area. Individual PAHs in soils ranged between below detection level to 526.66 ±18.62 ng/g. The sum of the concentration of the 8 PAHs (2.:8 PAHs) ranges (ng/g) were 17.30 ±1.19 to 62.21 ±0.97 in Kabete, 141.44 ±1.03 to 726.60 ±4.51 in Dandora; and 63.37 ±1.29 to 138.68 ±1.93 in Industrial Area. Medium weight PAHs, especially phenanthrene were more abundant than the low molecular weight compounds. There was a general increase in the monthly levels of P AHs in air at the Dandora and Kabete sites. On the contrary, there was a general decrease in the mean levels of P AHs in air from industrial area. Levels of P AHs in soils increased slightly in Dandora but declined slightly in Kabete. There was stronger seasonal dependence in levels of P AHs in air than in soils. Higher levels were observed during the cool season than the dry and wet seasons in Kabete and Dandora. A reverse trend was observed at the Industrial Area site. The Pearson's correlation coefficients as determined for the P AHs present between air and soil were positive at all the sites. The strongest and most significant intermatrix correlation was observed in Kabete (r=0.821) followed by Dandora (FO.S03) while that for Industrial Area was weak (r=0.166). Correlation coefficients for temporal and seasonal variations of P AHs were positive except in relation to Kabete soil (r=0.039) and Industrial Area air (r=0.792).

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