School of Natural Resources and Environmental Studies
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Item Causal Factors Responsible for Changes in the Attributes of Urban Green Spaces in Nairobi City County, Kenya(2024-07-26) Mbugua, Martin Wandie; Kamiri, Hellen; Kamau, PeterUrban green spaces are an important part of public open spaces and a common service provided by a city, town, or municipal council. In Nairobi City County, green spaces have been increasingly threatened by overcrowding, poor planning, weak management structures, and illegal alienation thus denying city residents access to the much-needed recreation and leisure facilities. As the population increases in urban areas, their activities impact the environment and therefore the ecosystem services. This study was done with the Principle of Intelligent Urbanism in mind, as the most prolific urban development theory developed by the International Congress of Modern Architecture. Quantitative and qualitative methods were used to collect data while a cross-sectional survey designs and stratified random sampling of the green spaces was employed, based on the location within the urban core and peri-urban of Nairobi County. Four green spaces (Karura Forest, Ngong Road Forest, Nairobi Arboretum, and City Park) with diverse characteristics and attributes were selected. A sample population of 384 visitors to the green spaces was surveyed for their perceptions of the functions, uses, and benefits of the green spaces. Our findings showed that management structures and population growth are the main causal factors responsible for changes in the attributes of urban green spaces.Item Temporal changes in Rainfall and Temperature influence on Solid Waste Generation in Bungoma County Urban Centres, Kenya(2024-07-28) Wafula, Godfrey Wekesa; Ouna, Tom; Kamiri, HellenGlobally, temperature and rainfall play an integral role in the management of solid waste in urban areas. This is because many countries especially, the developing countries conventionally rely on both variables in the management of waste. However, the urban environment faces many threats as a result of challenged waste management practices due to these climate stressors. This research aimed to assess how temporal changes in temperature and rainfall influence solid waste generation. The study was carried out in Bungoma county urban centres, specifically Bungoma town, Webuye, Kimilili, Kapsokwony, Chwele, and Sirisia townships. The study applied a stratified sampling technique to select the urban and peri-urban centres while random sampling was used to select respondents in residential dwellings, business people, urban residents, and officers from government institutions including public health and environment, water, and natural resources were interviewed. Ancillary data was collected using questionnaires and interview schedules while historical data was obtained to validate observed data. Data was analysed using descriptive and inferential statistics and summarized using tables, charts, and graphs. The findings of the study indicated that rainfall and temperature significantly influenced the generation of solid waste.Item Assessment of Solid waste generation and composition in Bungoma County Urban Centres for appropriate waste management approaches(2024-08-02) Wafula, Godfrey Wekesa; Kamiri, Hellen; Ouna, TomThe quantity and characteristics of urban solid waste are a result of the interconnectedness of diverse factors at play including social, economic, and environmental factors. These directly influence the choice of management practice at the household or community level. Understanding these relationships can help policymakers and urban planners develop more effective waste management strategies. This study aimed at assessing solid waste generation and composition in Bungoma county urban centers to inform on strategies for effective management of urban waste. The study was carried out in Bungoma County urban centers, specifically Bungoma town, Webuye, Kimilili, Kapsokwony, Chwele, and Sirisia townships. The study applied a stratified sampling technique to select the urban and peri-urban centers while random sampling was used to select respondents in residential dwellings, business people, urban residents, and officers from government institutions including public health and environment, water, and natural resources were interviewed. Ancillary data was collected using questionnaires and interview schedules while historical data was obtained from the Bungoma County Department of Environment and used to validate observed data. Data was analysed using descriptive and inferential statistics and summarized using tables, charts, and graphs. Our findings show that the highest waste was generated from residential homes, commercial, and municipal services. In terms of composition, biodegradable waste had the highest proportion, followed by plastics and glass waste. Population growth could be a key factor in the increased generation of the waste.Item Attributes of Urban Greenspaces and their Influence on Visitors’ Preferences in Nairobi City County, Kenya(Eastern African Journal of Humanities and Social Sciences Vol. 3 No. 1, 2024-07-07) Mbugua, Martin Wandie; Kamiri, Hellen; Kamau, PeterUrban green spaces refer to land covered with vegetation such as forests, street trees, parks, gardens, and water bodies in an urban setup. In this study, we sought to investigate the attributes of urban green spaces in Nairobi County and their relationships to visitor preferences. The Garden City Model advanced by Howard (1898) guided the study. Quantitative and qualitative methods were used to collect data while a cross sectional survey designs and stratified random sampling of the green spaces was employed, based on the location within the urban core and peri-urban of Nairobi County. Four green spaces (Karura Forest, Ngong Road Forest, Nairobi Arboretum, and City Park) with diverse characteristics and attributes was selected. A sample population of 384 visitors to the green spaces were surveyed for their perceptions of the functions, use, and benefits of the green spaces. Our findings showed that attributes of green spaces including location, accessibility, security, hygiene, and infrastructure could explain the interaction between green space provision factors and the frequency of visits, time spent in the green spaces and overall satisfaction of the visitors. Green space provision should be equitable in regard to distance to residents, quality of spaces, facilities and services and should be designed to meet the needs of diverse residents. Further, they should provide services and benefits such as shade, recreation, and health which are the main attractions to the green spaces. To achieve maximum benefits for visitors, green spaces need to be safe and physically accessible to all.Item Macroinvertebrate metrics and lipid profiles as potential indicators of land use influence in a high altitude tropical highland stream (Sagana River Basin, Kenya)(Elsevier, 2024) Odhiambo, Charles O.; Ngugi, Charles C.; Sharma, Rekha R.; Oyoo-Okoth, ElijahLand use practices near river ecotones result in numerous inputs of terrestrial materials into the river ecosystem. While macroinvertebrates population metrics is widely used in monitoring water quality changes, including those induced by humans, the use of lipid profiles in these organisms to monitor influence of land use practices is rather ignored. The aim of this study was to determine lipid profile in macroinvertebrates as potential indicator of human influence in Sagana River Basin, a high altitude tropical highland stream in Kenya. Sites were selected based on differences in land use activities delineated: forest with minimal land use activities, while cropland and saw milling areas had varying degrees of land use activities, with urban areas designated as sites with most human impacts. The macroinvertebrate metrics such as occurrence, abundance, diversity, percentage of oligo chaetes and chironomids (%OC), as well as the Ephemeroptera, Plecoptera and Trichoptera (%EPT) index differed relative to land use changes. Variation in the Fatty Acids (FAs), alcohols and sterols in benthic mac roinvertebrates was related to the land use activities along the stream. Evidently, streams traversing the urban areas had higher concentrations of Phospholipid fatty acids (PLFA), while streams traversing croplands had the highest neutral lipid fatty acids (NLFA). The dominance of monounsaturated FAs (MUFAs) in forest, shortchain FAs (SCFAs) and polyunsaturated FAs (PUFAs) in croplands and longchain FAs (LCFAs) near urban areas clear indicate different sources of these materials, mainly from terrestrial sources. Individual fatty acids, alcohols and sterols profiles discerned difference in land use changes. The concentrations of SCFAs, MUFAs, LCFAs, TeoH, 27Δ5.22, 28Δ5,24, 28Δ5,22, 29Δ5,22 and 29Δ5,22 in the benthic macroinvertebrates samples were positively associated with OC%, EPT, total abundance and eH’. Meanwhile the concentration of phytol, AqOH, 27Δ5 and SCOH were associated with Simpson index. The current findings support the combination of macroinvertebrates species composition, abundance, diversity and lipids profiles to detect land use activities at the riverine scale. While implementing catchment-based river management and conservation activities should incorporate lipid analysis as a management tool. There is need for continuous monitoring of long term trends in land use activities on the changes in lipid content of the macroinvertebratesItem Fishing power of conventionally harvested wetland baitworms compared to black soldier fly larvae as alternative baits in tropical artisanal hook fishery(2018) Kihia, C. M.; Gitonga, L. M.; Tembo, J. E.; Kanyeki, E.; Munguti, J.; Muli, B.Extensive and intensive, harvesting of earthworms and polychaetes from wetland substrate, for artisanal hook fishery, affect structural and functional integrity of these critical habitats. Cultured Black Soldier Fly larvae (BSF, Hermitia illucens), are suggested as sustainable alternatives. This study compares bait and landed fish properties of wild earthworm (Eisinia sp) and polychaete (Marphysa mossambica), with cultured BSF larvae as bait, in hook fishery. Participating fishers, were supplied with known quantity of bait, and the duration and quantity of fish obtained, monitored. Hook casting, attractiveness and killing power, as well as fish quality and quantity, were computed and compared among sites and bait. Results reveal significant (P<0.05) differences in bait and landed fish properties. Lower bait casting (8.8%), but higher attractiveness (0.96) and killing power (55%), were obtained using polychaete in marine habitats, than either earthworms or BSF. Similarly, higher fish landings s (0.59 kg.hr-1), were obtained using polychaete, than comparable BSF or earthworm (<0.1 kg. hr-1. We surmise that wild baitworms, are easier to handle, attract and land more fish, leading to higher variety and abundant landed fish, than cultured BSF larvae. Lower performance of BSF is attributed to; poor response of target fish to imprinted physical and chemical attributes of the bait. This may imply that fishers, have limited justification for substituting cultured BSF, with conventional wild baitworm in artisanal fishery. Further elucidation of drivers to bait choice and performance coupled with improvement in cultured bait quality might, provide sustainable solutions.Item Black Soldier Fly (Hermetia illucens) Larvae Meal as a Sustainable Protein Source for Fish Feed Production in Kenya(SPRINGER, 2023) Opiyo, M. A.; Nairuti, R. N.; Ngugi, C. C.; Holeh, G. M.Aquaculture has been ranked as one of the fastest-growing food sub-sectors, providing quality protein to better the livelihoods of rural communities alongside curbing malnutrition and food security globally. Nonetheless, the industry’s sustainability has been threatened by the high cost of fish feeds, which account for approximately 60–70% of the total operational costs. Fish meal (FM) has been extensively utilised as the main source of protein in the diets of farmed finfishes. However, due to declining capture fisheries and competing uses from other animal feed producers, the ingredient has become a scarce resource with limited availability and high prices. Black soldier fly larvae (BSFL) have been identified as a promising alternative protein source in fish feeds. BSFL are documented to have high nutritional content: crude protein (of up to 64% dry matter), essential amino acids, fatty acids, and other micro-nutrients which are vital for the growth of fish. BSFL meal has the potential success of replacing FM in the diets of various fish species. This chapter focuses on analysing recent research work in BSFL proximate and chemical composition, its current utilisation in fish feeds and gaps to be filled in its complete utilisation as an ingredient in commercial feed production. This information is expected to help both cottage and commercial fish feed producers utilise BSFL in feed production in Kenya and further will promote the sustainability of the aquaculture industry.Item Spawning interactions between hatchery-reared and wild naturalized rainbow trout (Oncorhynchus mykiss, Walbaum, 1792) in high-altitude tropical streams, Kenya(Wiley, 2022-07) Njue, Justus N.; Ngugi, Charles C.; Mucai, Muchiri; Opiyo, Mary A.Rainbow trout (Oncorhynchus mykiss) is among the most widely translocated fish species in the world. The current study evaluated the spawning interactions between naturalized and wild rainbow trout from two high-altitude second-order streams, in Kenya. Data on total length, weight, condition factor, fecundity, fertilization, egg diameter and fry survival were collected on spawning rainbow trout between March and December 2021. Length–weight relationship showed parabolic equations as W = 0.0144L2.900, W = 0.0069L3.0285 and W = 0.00027L3.175 for wild fish stock, hatcheryreared and wild × hatchery-reared rainbow trout, respectively. Total fecundity differed significantly among the hatchery-reared, wild fish and the cross of the two (p < 0.05). The fertilization rate showed significant differences (p < 0.05), with no discernable difference observed between the hatchery-reared and crossed (wild × hatchery-reared). There was a positive correlation among the total fecundity to female egg weight, female body weight, fertilization rate and eyed egg survival in all the populations. Relative fecundity was significantly different among the three groups of fish (p < 0.05), but the differences between the hatchery and the crossed (wild × hatchery-reared) fish showed no significant differences. We recommend the use of crossed (wild × hatchery-reared) populations for fry production for use in aqua-culture as they presented the highest fecundity and gave the best outcome of fry with high survival.Item Analysis of Short-Term Drought Episodes Using Sentinel-3 SLSTR Data under a Semi-Arid Climate in Lower Eastern Kenya.(2023-06) Musyimi, Peter K.; Sahbeni, Ghada; Timár, Gábor; Weidinger, TamasThis study uses Sentinel-3 SLSTR data to analyze short-term drought events between 2019 and 2021. It investigates the crucial role of vegetation cover, land surface temperature, and water vapor amount associated with drought over Kenya’s lower eastern counties. Therefore, three essential climate variables (ECVs) of interest were derived, namely Land Surface Temperature (LST), Fractional Vegetation Cover (FVC), and Total Column Water Vapor (TCWV). These features were analyzed for four counties between the wettest and driest episodes in 2019 and 2021. The study showed that Makueni and Taita Taveta counties had the highest density of FVC values (60–80%) in April 2019 and 2021. Machakos and Kitui counties had the lowest FVC estimates of 0% to 20% in September for both periods and between 40% and 60% during wet seasons. As FVC is a crucial land parameter for sequestering carbon and detecting soil moisture and vegetation density losses, its variation is strongly related to drought magnitude. The land surface temperature has drastically changed over time, with Kitui and Taita Taveta counties having the highest estimates above 20 ◦C in 2019. A significant spatial variation of TCWV was observed across different counties, with values less than 26 mm in Machakos county during the dry season of 2019, while Kitui and Taita Taveta counties had the highest estimates, greater than 36 mm during the wet season in 2021. Land surface temperature variation is negatively proportional to vegetation density and soil moisture content, as non-vegetated areas are expected to have lower moisture content. Overall, Sentinel-3 SLSTR products provide an efficient and promising data source for short-term drought monitoring, especially in cases where in situ measurement data are scarce. ECVs-produced maps will assist decision-makers with a better understanding of short-term drought events as well as soil moisture loss episodes that influence agriculture under arid and semi-arid climates. Furthermore, Sentinel-3 data can be used to interpret hydrological, ecological, and environmental changes and their implications under different environmental conditions.Item Hourly reference evapotranspiration analysis using synoptic meteorological measurements and ERA5 reanalysis data from Kenyan Counties(2023-09) Musyimi, Peter K.; Mendyl, Abderrahmane; Agustiyara, Agustiyara; Székely, BalázsKenya has had five failed rain seasons for the last three years. In this context, there was a mass recurrent crop failure, death of livestock and wildlife, persistent water scarcity, and droughts of varying intensities. There have been a lot of challenges in assessing climate change and variability impacts in Kenya due to limited data sources. Further, assessing the local and regional effects on the hydrological cycle, food security, and available water resources remains a great regional threat. Reference evapotranspiration, is the evaporative power climatic parameter of the atmosphere, vital for water budgets on the land surface. The study’s main goal was to analyze hourly reference evapotranspiration, from two climatic regions using single levels ERA5 hourly dataset from 2000 to 2022. The dataset was sought from three stations from, arid, and semi-arid savannah tropical conditions regions (Voi Garissa, and Mombasa) with elevations between 57 m to 579 m, and three (Trans-Nzoia, Nyeri, and Embu) sought from humid Kenya highlands (>1350 m). Reference Evapotranspiration was calculated using Penman-Monteith (FAO56), the standard methodology developed by Food and Agriculture Organization. Results from 5 years (2018 to 2022) in Taita-Taveta County indicated that ranged from 0.17±0.2 mm/hour in 2020 to 0.22±0.2 mm/hour in 2022. Daily averages were 4.17±1.2 mm./day to 5.2±1.1 mm/day in 2020 and 2022 respectively. The mean monthly and was highest in March with an estimated value of 159.7±53.7 mm/month while the lowest was 120±15 mm/month in December. This is because March falls at the onset of the long rainy season in Kenya where precipitation is high while December is the last month of the short rainy season when precipitation reduces significantly. These results are vital because they enhance comparisons of the spatial climatological patterns and variability of seasonal precipitation about the evaporative power and demand variation across regions. Further, it will necessitate investigations of uncertainties from the datasets for better decision-making after comparisons with analysis from field meteorological datasets and soil moisture data measurements currently being carried out in Kenya. Further comparison of the results with reference evapotranspiration from the original station and the Global Land Evaporation Amsterdam Model dataset will also be investigated.