Masters Theses:Department of Biological Sciences
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Item Putative Functions of Novel Antennae Chemosensory Gene Repertoire of Male Tsetse Fly, Glossina morsitans morsitans(BILLIAH KEMUNTO BWANA, 2022-11) BWANA, BILLIAH KEMUNTOTsetse fly is a primary vector of Human African Trypanosomiasis and Animal African Trypanosomiasis. Tsetse fly exploits chemical cues from the environment to distinguish a non- from suitable hosts. Genes in tsetse fly antennae code for proteins and receptors that directly or indirectly mediate chemoreception. While chemoreception-associated genes have been annotated, antennal genes in the Glossina. m. morsitans genome with important functions have not been characterized. Antennaespecific raw reads from adult flies exposed to four treatments, namely, fed, unfedexposed to ε-nonalactone attractant, unfed-exposed to δ-nonalactone repellant and unfed-exposed to paraffin diluent (control) were mapped onto G. m. morsitans geneset. Reads that did not map were isolated and de novo assembled into transcripts. Protein-coding gene regions associated with these transcripts were predicted, annotated and curated as partial/complete genes. Annotated putative orthologs/homologs for these genes in Drosophila melanogaster (Dm), Musca domestica (Md) or Anopheles gambiae (Ag) genomes were identified. Finally, differential expression of the novel or existing genes in relation to odor exposures relative to no-odor control (unfed flies) were assessed and expression of existing genes quantified through qPCR. Results showed that 45.21% of the sequenced reads did not map to the gene set. These reads assembled into 72,428 unique transcripts that yielded 592 genes among which 202 were novel and 390 were improvements of existing genes in the G. m. morsitans genome. Among the novel genes, 94 had orthologs in Dm, Md or Ag and 88 had homologs in UniProt databases. These orthologs were putatively associated with non-canonical olfactory roles, thus providing insight into their specific roles in antennal physiological processes. A novel gene (GMOY014237.R1396) and 15 existing genes were differentially expressed in response to the attractant or repellent. Differential expression through qPCR analysis unveiled three antennal transcripts, i.e., the coat protein epsilon, cyclin-dependent kinase and odorant receptor 45, all three up-regulated in response to the attractant. Novel genes sequences were adopted by VectorBase, updating the existing G. m. morsitans annotations. This study identified 108 potentially tsetse fly-specific antennal genes. The novel antennal genes could be used as baseline data in studies of other tsetse fly species, and with an orientation towards attraction and or repellency in their control.Item Bacterial Food Contaminants in Vended Fast Foods, Soil and Water in Embu Town, Kenya(SUSAN WAIRIMU MURIUKI, 2020-11) Muriuki, Susan WairimuReady to eat fast food vending business has grown exponentially however, the microbiological safety of most of these fast foods is questionable. Despite the cholera outbreak in Embu in 2017, diminutive information exists on waterborne and foodborne illness outbreaks resulting from bacterial pathogens in Embu Town and the nearby Kangaru Market. Thus this study aimed to isolate and characterize bacterial food contaminants in the vended fast foods and their surrounding environment in Embu Town and nearby Kangaru Market. Bacterial isolates were isolated from; fried fish, African sausages, roasted meat, samosa, fries, vegetable salads, soil and water. Antibiotic susceptibility testing was done using the Kirby-Bauer method. DNA was extracted from pure isolates using the phenol-chloroform method. The 16S rRNA and resistant genes were amplified with the respective primers. Taxonomy was assigned to each Operational Taxonomic Units using BLAST. Sequence alignment and construction of the phylogenetic tree were done using MEGA X. Total community DNA was extracted from samples using the phenol-chloroform method. The 16S rRNA gene variable region (V4-V7) of the extracted DNA was amplified and library construction was performed according to Illumina sequencing protocol. Sequence analysis was done using QIIME2 while Analysis of similarity (ANOSIM) test, based upon Bray-Curtis distance, Non-metric Multidimensional Scaling (NMDS), redundancy analysis (RDA) as well as Hierarchical clustering of the samples, were carried out using the R programming language. Taxonomic groups were derived from the number of reads assigned to each taxon at all ranks from domain to species using the taxa summary.txt output from the QIIME2 pipeline. Antibiotic resistance of the isolates was; chloramphenicol 90%, cefotaxime 84.29%, nalidixic acid 81.43%, tetracycline 77.14%, amoxicillin 72.86%, gentamycin 48.57%, streptomycin 32.86% and trimethoprim + sulphamethoxazole 30%. Isolate KMP337, exhibited significantly high antibiosis against S. aureus recording an average inhibition of diameter mean and standard error (SE)16.33±0.88mm respectively at P = 0.001. Polymerase chain reaction detected the presence of resistance genes; tet (A), bla TEM, strB, dfr (1), bla Amp, and Flor genes. The isolates clustered in five main genera namely Bacillus, Paraclostridium, Lysinibacillus, Virgibacillus, and Serratia all having similarity of above 90%. The OTUs were distributed among twenty-three bacterial phyla across the samples with the most abundant belonging to Proteobacteria (52.81%), Firmicutes (31.16%), Bacteroidetes (8.00%) and Lentisphaerae (0.001%). The OTUs were shared among archaea as follows; Candidatus nitrososphaera (83.89%) and Nitrososphaera (11.43%). Lactobacillus perolens, Pseudomonas spp., Clostridium spp., and Bacillus cereus were detected in abundance across the samples. Potential pathogens in risk group 2 including Rickettsia spp. and Brucella spp., Coxiella spp. in risk group 3 were detected. Uncultured Candidatus koribacter sp, Candidatus microthrix sp. and Candidatus solibacter sp. were detected in food. This study confirmed the presence of antibiotic-resistant foodborne potential pathogens in vended fast foods and the soil in Embu Town and Kangaru Market. The study, therefore calls for continuous monitoring of bacterial status and hygienic handling of vended foods. The detection of potential pathogens calls for stringent hygiene measures in food vending operations, especially in Kangaru Market.Item Inheritance patterns of morphological Characters and the karyotype of crotalaria Species in kenya(Mercy Achieng Wasonga, 2020-11) Wasonga, Mercy AchiengSlender leaf (Crotalaria spp.) is an African indigenous leafy vegetable with high nutritional benefits. However, despite these benefits, this vegetable has been neglected in terms of research, and information on breeding techniques is scanty. This study aimed to determine the inheritance patterns of morphological characters and the karyotype of Crotalaria. Crotalaria accessions from Kakamega, Bungoma, Vihiga, Busia, Siaya, Homa Bay, Kisumu, Migori and Kisii were subjected to inheritance studies under similar field conditions. The experiments were carried out at the University of Embu Farm. Two landraces FKK 0039 and FHB 0211 were used to develop an artificial pollination protocol. The experiment was set up in a completely randomized design (CRD) in a greenhouse with Crotalaria ochroleuca as the female parent and Crotalaria brevidens as the male parent. Six plants were planted in pots replicated three times for both male and female parents. Six-day-old flower buds of the female parent were emasculated and pollen from a freshly opened flower was rubbed over the stigma of the emasculated flower. The pollinated stigma was inserted back into the keel petal and covered by the wing and standard petal. Data on crossing success rate, pod and seed production was subjected to analysis of variance. Eleven parents of Crotalaria were used in a diallel cross to determine genetic control of morphological traits. The experiment was laid out in a triple lattice design with 110 hybrids and 11 parents. The data were evaluated for the inheritance of six traits using Hayman’s method and Griffing’s model 1 for estimation of gene action, general and specific combining abilities. A mean separation was done by Tukey’s HSD test at 5% probability level. Twenty Crotalaria seeds were grown in petri dishes for karyotype studies. Chromosome morphology was observed and the chromosome numbers were noted. Chromosome positioning at different mitotic stages were observed under a compound microscope. The developed artificial pollination method showed 75% success rate in the interspecies cross of C. ochroleuca and C. brevidens. Time of crossing did not significantly influence the success rate, pod and seed production. Data showed significant additive and dominance gene effects for two and six traits, respectively. The general combining ability and specific combining ability were significant for plant height and leaf length. This study recorded a diploid chromosome number of 2n = 2x = 16 for five Crotalaria species; C. trichotoma, C. brevidens, C. ochroleuca, C. spectabilis and C. intermedia. The diploid chromosome number of 2n = 2x = 16 was reported for the first time in C. trichotoma. The study demonstrated artificial interspecific pollination of Crotalaria by rubbing method involving keel petal incision. This protocol lays the foundation for genetic studies and improvement of Crotalaria spp. The study showed the importance of general combining ability for parental selection and specific combining ability in hybrid production.Item The success of eco-engineering mangrove restoration in a high energy area, at gazi bay, kenya(Gladys Kinya, 2024-08) Kinya, GladysMangroves and their ecosystem offer a range of globally recognized benefits, yet they continue to be lost and degraded. Efforts to restore lost mangroves using conventional methods in high-energy areas result in low success rates due to the removal of seedlings via wave’s action. This study assessed the efficacy of using modified Riley Encasement Methods (REMs) in the restoration of mangroves in high-energy areas at Gazi Bay, Kenya. Prior to the mangrove planting experiment, mapping for mangrove cover change, and assessment of vegetation and soil conditions were done. Global Positioning System (GPS) device was used to record the study site coordinates. Landsat images were systematically sampled using these coordinates from the United States Geological Survey (USGS). Vegetation and soil baseline data were collected in 49 square plots of 100 m2 ; established along belt transects perpendicular to the shoreline. The mangrove vegetation structural data that was collected included; species composition, tree height (m), and stem diameter (cm); from which the importance value index (IV), basal area (m2 ha-1 ) and standing density (stems ha-1 ) were derived. Sediment cores were made in the center of each square plot for carbon and grain size analysis. Mangrove (Rhizophora mucronata) planting was done using a randomized complete block design (RCBD) in which the planting area was divided into three sections. On each section, one block measuring 7 m by 5.5 m was established, resulting to three blocks namely A, B, and C. Within each block, treatments that involved use of bamboo and different-sized PVC pipes were randomly assigned locations. Monitoring involved assessment of survival and growth parameters including shoot growth, number of leaves, number of internodes, number of branches and leaf area. Statistical data analysis was done using SPSS version 26.0, GRADISTAT computer program and Microsoft Excel 2019. The findings of this study were that the mangrove forest was highly degraded recording relatively low proportions of silt and clay (3.03 ± 0.17%), soil organic matter (6.33 ± 0.24) and soil organic carbon (5.52 ± 0.10). Following repeated measures of Analysis of Variance (ANOVA) and a post-hoc Tukey's Honest Significant Difference (HSD) test (p < 0.05), the results of the planting experiment revealed significant variations in survival and growth rates among treatments. Seedlings grown within PVC encasements recorded significantly higher survival rates (43%) compared to those in the bamboo (1%) and control groups (4%). These findings suggest that PVC pipes were efficient in supporting and protecting seedlings from external forces. The study highlights the potential of adopting the encasement technique in mangrove restoration. These findings are particularly relevant to environmental conservation policies, climate change mitigation strategies, and coastal community development programs. Current mangrove restoration policies should consider the potential of eco-engineering techniques in addressing challenges facing mangrove restoration in high energy sites.Item Genetic Diversity and Antigenic Variation of Rabies Viruses from Different Host Species in Eastern and Western Parts of Kenya(Evalyne Nyambura Wambugu, 2024-08)Rabies, a viral illness that causes deadly encephalitis, claims over 59,000 lives globally each year, with approximately 2,000 deaths happening in Kenya despite effective countermeasures for both humans and dogs. This study sought to improve the understanding of the genetic differences of the rabies virus (RABV) collected from the brain stem tissues of animals with suspected rabies in two geographic rabies hotspots: Makueni county, in the eastern region, and Siaya county, in western Kenya. Furthermore, the study investigated discrepancies among the antigenic sites of the RABV vaccines currently approved for use in Kenya and the study samples. Between July 2021 and September 2022, 164 brain stem tissues were collected from animals suspected of rabies after testing positive for RABV antigens using rapid diagnostic kits. Subsequently, in the laboratory, the samples were re-screened for rabies ribonucleic acid (RNA) by quantitative Real-Time Reverse-transcription Polymerase Chain Reaction (qRT-PCR) that targets the RABV Large-structural protein gene (L gene). Negative samples by the L gene qRT-PCR were analyzed by conventional PCR that targets the RABV Nucleoprotein gene (N gene). Phylogenetic analysis was carried out using whole genome sequences (WGS), as well as single genes (nucleoprotein (N) and glycoprotein (G). The amino acid changes in the antigenic regions of individual proteins (N and G) in the research sequences were compared to three RABV vaccine sequences: Pitman-Moore L503 (PM), Challenge Virus Standard (CVS), and Pasteur vaccine (PV). The L gene qRT-PCR revealed positive results for 156 of the 164 brain stem tissues. Eight samples failed to amplify the L-gene but amplified by N gene. On sequencing, 141 samples produced sequences suitable for analysis. Phylogenetic analysis using WGS and single genes confirmed that the RABV strains belonged to the Cosmopolitan clade that branched into two distinct phylogeographic subclades: sequences from eastern Kenya predominantly grouped within the Africa 1b subclade with only three sequences in the Africa 1a subclade. Conversely, the sequences from western Kenya formed clusters within the Africa 1a subclade while three were in the 1b subclade. In keeping with this phylogeographic clustering, the western Kenya Africa 1a subclade's closest ancestor was found in Sudan, while the eastern Kenya Africa 1b subclade had its origin in Tanzania. Within the western Kenya 1a subclade, 8 lineages were observed and 5 within the eastern Kenya 1b subclade. The amino acid homologies of the N gene between the study sequences and the vaccines for RABV were found to be approximately 97.6% for the PV vaccine strains, 98.5% for PM, and 97.8% for CVS. Similarly, the homologies with the G gene were at least 92.95% for PV, 92.19% for PM, and 93.3% for CVS. Our findings corroborate the geographic segregation of RABV between the eastern and western regions of Kenya. The data indicates that there is restricted viral movement, likely facilitated by the transportation of domestic dogs by humans. Good vaccine efficacy is predicted by the low amino acid variations in the antigenic sites of RABV vaccines and the study samples, suggesting that a lack of programmatic vaccination coverage is a major contributor to the endemicity of RABV in Kenya.Item Epidemiology of urinary schistosomiasis and Soil-transmitted helminthiasis among women of Reproductive age in kwale county, kenya(Samuel Mutua Ngui, 2024-08)Schistosomiasis and soil-transmitted helminthiasis (STH) are prevalent infections in Sub-Saharan Africa especially in low-income setting. School aged children have been the main target of preventive chemotherapy in the national school-based deworming program. This study investigated the epidemiology of urinary schistosomiasis and soiltransmitted helminthiasis among women of reproductive age in Mwaluphamba, Kwale County, Kenya. A community-based cross-sectional study design was employed with a systematic random sampling to recruit 422 women of reproductive age (15-49 years) from four villages in Mwaluphamba location. Stool specimens were collected and examined using the Kato Katz method, while filtration technique was used to analyze urine specimens. Participants’ sociodemographic details were obtained using a standardized questionnaire. Statistical analyses were carried out using SPSS version 25, with a significance level set at p≤0.05. The prevalence of urinary schistosomiasis was 4.7% (95% CI 2.8%-6.9%), while the prevalence of soil-transmitted helminthiasis infection was 4.5% (95% CI 2.6%-6.7%). There were no significant differences in the prevalence of urinary schistosomiasis among different age groups (F=4.454, p=0.196), as well as for hookworms (p=0.235) and Trichuris trichiura (p=0.099). Urinary schistosomiasis showed a statistically significant association with haematuria, proteinuria, and leukocyturia. In terms of infection intensities, urinary schistosomiasis ranged from 1 to 120 eggs/10 mL of urine, with a median egg count of 18.45 eggs/10 mL. Patients were diagnosed with light infections of 56.16 eggs/gram and 48.48 eggs/gram for Trichuris trichiura and hookworms, respectively. The study revealed that women without latrines had a 15.70 times higher risk of urinary schistosomiasis compared to those with access to latrines. Additionally, the use of surface water (aOR=1.032, 95% CI 1.023-1.432, p=0.010) and crossing rivers (aOR=1.13, 95% CI 0.290-1.611, p=0.009) were identified as statistically significant risk factors for urinary schistosomiasis. In univariable regression analysis, defecating around water sources (OR=4.34, CI 1.466-12.883) was significantly associated with the prevalence of soil-transmitted helminthiasis (p=0.008). This study provides valuable insights into the prevalence and intensity of urinary schistosomiasis and geohelminths in Mwaluphamba location, which can inform the strengthening of control and elimination programs for these neglected tropical diseases. Based on these findings, it is recommended that comprehensive and sustained intervention strategies be implemented, focusing on improving water, sanitation, and hygiene (WASH) practices, enhancing health education, and ensuring regular mass drug administration (MDA) programsItem Genetic diversity of selected kenyan eucalyptus species and their suitability as power transmission poles(DAISY CHEBET, 2024-08)Eucalyptus is a genus in the Myrtaceae family that has many varieties of species. Among these species, Eucalyptus grandis, E. globulus, E. saligna and E. camaldulensis are majorly found in Kenya. E. grandis is the only species that is preferred for use as a source of power transmission poles. This species is known to mostly depend on high rainfall but due to global warming, there is insufficient rainfall making E. grandis to be unavailable hence the demand for this particular species is not met in electrification. There are other Eucalyptus species that occur naturally such as E. camaldulensis and E. globulus, and therefore it was important to carry out molecular phylogenetics and analyze the phenotypic traits of these other species to inform their use as power transmission poles in order to avoid the over exploitation of E. grandis. In this study, the phenotypic traits investigated included measuring tree height and diameter at breast height (DBH), while molecular data was obtained from sequences of MatK, RbcL and TrnL-F genes from the selected species. Evolutionary analyses such as nucleotide substitution rates, base composition disparity index, evolutionary divergence, nucleotide diversity indices and phylogeny construction were conducted in MEGA 11. Significant differences in DBH and height among Eucalyptus species were noted when the phenotypic data was analyzed using ANOVA (p≤0.05). The results obtained suggested that E.robusta, E.paniculata, E.maculata, E.dunnii, E. camaldulensis and E.citriodora might be used as power transmission poles but they are limited due to their shorter height (<30 meters). However, E. tereticornis and E. glaucina have the prefered DBH (18.3–28.3 cm) and height (>30 meters) and hence can be used as substitutes for E.grandis. Generally, the molecular phylogeny study suggested that most of the studied Eucalyptus species have a common ancestor because of the short genetic distances between them, low substitution rates and low nucleotide bias disparity index. The resulting phylogenetic trees will enhance knowledge on genetic relatedness of Kenyan Eucalyptus species as well as enhancing the efforts towards improvement and identification of known species with standard DBH and height for use as power transmission poles. Further studies involving more Eucalyptus species from various regions are needed to better understand the genetic diversity of the genus Eucalyptus and identify more species for use as alternative power transmission poles.Item Genetic factors implicated in asymptomatic malaria infections(UoEm, 2024-08) Amwoma, Joseph GisainaPlasmodium falciparum malaria infections can be classified as either asymptomatic or symptomatic which includes uncomplicated malaria, severe malaria, cerebral malaria, and naïve malaria. In symptomatic cases, individuals infected with the parasites display symptoms associated with malaria. In contrast, asymptomatic cases do not show any classical symptoms and, therefore, act as reservoirs of the parasite. The persistence of P. falciparum parasites in an asymptomatic malaria individual plays a significant role in maintaining transmission. However, the molecular mechanisms underlying P. falciparum's persistence in asymptomatic infections remain largely unknown. This study hypothesised that changes in the parasite's gene expression during asymptomatic infections might enhance their adaptability and fitness and therefore contribute to their persistence in the host. To investigate this hypothesis, a transcriptome analysis was done to identify P. falciparum's genetic factors that are associated with asymptomatic infections. Whole blood RNA profiles from 25 field samples (15 asymptomatic (ASM) and ten uncomplicated malaria (UM) samples) were analyzed. In addition, publicly available transcriptome datasets from whole blood samples of 35 individuals with asymptomatic malaria (ASM, n=11), uncomplicated malaria (UM, n = 12), and naïve-malaria (NM, n = 12) were included for differential gene expression analysis, long noncoding RNAs expression analysis, and single nucleotide polymorphisms analysis within the virulent genes of P. falciparum. Data analysis revealed 755 differentially expressed genes (DEGs) between asymptomatic carriers and individuals with uncomplicated malaria, and 1773 DEGs between NM and ASM. Among the top differentially expressed genes were numerous genes coding for proteins of unknown functions (PUFs). The ontology analysis of DEGs revealed activated pathways linked to host-parasite interactions, including antigenic variation, immune evasion, crystalloid, apoplast, and binding processes and supressed pathways associated with carbon metabolism. Additionally, the analysis identified 28 immune evasion genes associated with host-parasite and symbiotic interactions, such as cell adhesion, evasion of the host immune response, modulation by symbionts of host cellular processes, and responses to biotic and external biotic stimuli. Moreover, 237 differentially expressed noncoding RNAs were detected when comparing asymptomatic carriers (ASM) to those with uncomplicated malaria (UM). Among these, five RNAs were observed to interact with six immune evasion genes, indicating a potential role in modulating the immune response during asymptomatic infections. The analysis of var gene family expression did not reveal statistically significant differences in the expression levels of the var groups. However, two genes, CUFF.75 and CUFF.203, were upregulated in asymptomatic infections compared to uncomplicated malaria infections. These findings demonstrate that P. falciparum establishes asymptomatic infections by suppressing the central carbon metabolism and expressing immune evasion genes, which mediate sequestration to avoid clearance and adapt to the host's defenses, resulting in long-lasting chronic infections. Additionally, the study identifies potential biomarkers for detection of asymptomatic malaria. These findings provide novel insights into P. falciparum genetic factors that confer a fitness advantage during asymptomatic infections.Item Cover Change and Vegetation Carbon Stocks of Mangrove Forests in Lamu County, Kenya(UoEm, 2023-04) Mbatha, Anthony MutuaMangroves around the world are being threatened by a combination of natural and human factors. Losses of mangroves leads to reduced forest cover and enhanced carbon emission. This study assessed cover change, forest structure, natural regeneration, and carbon stocks of mangroves in Lamu County, Kenya. Landsat images were used to assess cover change from 1990 to 2019, and structural data were obtained in the field using the plot method. Using stratified random design, mangroves were sampled in 152 square plots of 400 m2 along belt transects established perpendicular to the waterline. Within each plot, all trees with stem diameters ≥ 2.5 cm were identified, counted and position marked, while those < 2.5 cm were counted and classified as juveniles. The following parameters were recorded: tree height (m), stem diameter (cm), and canopy cover (%); from which stem density (stems ha-1), basal area (m2 ha-1), volume (m3 ha-1), and biomass (t ha-1) were enumerated. Six mangrove species were encountered during this study. Based on importance value index, the dominant mangrove species in Lamu were Rhizophora mucronata (Lam.) and Ceriops tagal (perr.) C.B. Rob., that accounted for more than 70% of the mangrove formations. Mean standing density of the mangroves was estimated at 2,339±241 stems ha-1 (range:1,607-3,092 stems ha-1), with a basal area of 24.26±3.18 m2 ha-1, and volume of 157.97±15.22 m3 ha-1. At least 42% of the forest was stocked with low-quality poles, indicating prolonged human pressure. However, natural regeneration rate of 7,342±450 juveniles ha-1 observed in the forest was considered adequate to support forest recovery following disturbance. The mean biomass was estimated at 354.98±49.81 Mg ha-1. This translates to vegetation carbon storage of 166.56±23.41 Mg C ha-1. Mangroves in Lamu were estimated at 35,678 ha, representing 62% of the country’s total. Approximately, 1,739 ha of mangroves were lost between 1990 and 2019, mainly due to anthropogenic activities, representing a decline of 60 ha yr-1. Total emission from loss and degradation of mangrove vegetation in Lamu was estimated at 41.64 Mg C ha-1; which translates to 9,169.13 Mg CO2e yr-1. Assuming an offset price of US$10/Mg CO2e, the estimated cost of avoided emissions in Lamu County is US$91,691.3 yr-1 plus other co-benefits such as fishery support and shoreline protection. Mainstreaming mangroves and associated blue carbon ecosystems into national development and climate change agendas could accelerate Kenya’s achievements to the Paris Agreement and other processes.Item Mathematical Modelling and Simulation of Competition for Students’ Population Via Influence And Economic Factors With Holling Type Ii Response(UoEm, 2023-08) Odhiambo, Brian OtienoThe increase in Kenyan population attracted the establishment of more schools, both public schools and private schools. This was due to the need to cater for the increasing number of students being enrolled in schools. Moreover, the dynamics of students’ population both in public schools and private schools have created the changes in the schools’ population. This occurs through transfer from one category of school to the other, through completion of the learning period and through drop out due to unknown reasons. This subjected both the public schools and private schools to compete in order to maintain a good number of students under their custody. In this work, a modified Lotka-Volterra model of schools and non-enrolled entities population in the education system is studied. Private schools and non-enrolled entities play the role of a predator in public schools. Again, public schools and non-enrolled entities play the role of predators in private schools. This study uses integrated Holling type II functional response to analyze the model. Establishment of equilibrium points and their stability are determined using the Routh-Hurwitz criterion and eigenvalue method. Global stability has been done for the positive equilibrium point. Hopf bifurcation is also done around the positive equilibrium point. Data obtained from the Ministry of Education and the sources cited were used to estimate the model parameters. Finally, graphical illustration of various parameter is derived to show their effect on schools when they are varied. The study revealed that the increase in transfer rate from private to non-enrolled, transfer rate from public to non-enrolled and the non-enrolled entity predation on public schools greatly affects the schools’ population as they are the ones leading to predation in school. Therefore, proper strategies should be developed to focus on reducing the parameters that affects the schools’ population adversely to avoid leading schools’ population to extinct.Item Putative Functions of Novel Antennae Chemosensory Gene Repertoire of Male Tsetse Fly, Glossina Morsitans Morsitans(UoEm, 2022-11) Bwana, Billiah KemuntoTsetse fly is a primary vector of Human African Trypanosomiasis and Animal African Trypanosomiasis. Tsetse fly exploits chemical cues from the environment to distinguish a non- from suitable hosts. Genes in tsetse fly antennae code for proteins and receptors that directly or indirectly mediate chemoreception. While chemoreception-associated genes have been annotated, antennal genes in the Glossina. m. morsitans genome with important functions have not been characterized. Antennaespecific raw reads from adult flies exposed to four treatments, namely, fed, unfedexposed to ε-nonalactone attractant, unfed-exposed to δ-nonalactone repellant and unfed-exposed to paraffin diluent (control) were mapped onto G. m. morsitans geneset. Reads that did not map were isolated and de novo assembled into transcripts. Protein-coding gene regions associated with these transcripts were predicted, annotated and curated as partial/complete genes. Annotated putative orthologs/homologs for these genes in Drosophila melanogaster (Dm), Musca domestica (Md) or Anopheles gambiae (Ag) genomes were identified. Finally, differential expression of the novel or existing genes in relation to odor exposures relative to no-odor control (unfed flies) were assessed and expression of existing genes quantified through qPCR. Results showed that 45.21% of the sequenced reads did not map to the gene set. These reads assembled into 72,428 unique transcripts that yielded 592 genes among which 202 were novel and 390 were improvements of existing genes in the G. m. morsitans genome. Among the novel genes, 94 had orthologs in Dm, Md or Ag and 88 had homologs in UniProt databases. These orthologs were putatively associated with non-canonical olfactory roles, thus providing insight into their specific roles in antennal physiological processes. A novel gene (GMOY014237.R1396) and 15 existing genes were differentially expressed in response to the attractant or repellent. Differential expression through qPCR analysis unveiled three antennal transcripts, i.e., the coat protein epsilon, cyclin-dependent kinase and odorant receptor 45, all three up-regulated in response to the attractant. Novel genes sequences were adopted by VectorBase, updating the existing G. m. morsitans annotations. This study identified 108 potentially tsetse fly-specific antennal genes. The novel antennal genes could be used as baseline data in studies of other tsetse fly species, and with an orientation towards attraction and or repellency in their control.Item Food web structure of Nematode communities associated with rice in Mwea, Kenya(UoEm, 2023-07) Mokuah, DorcasNyabokeIn Kenya, rice is an important staple crop after wheat and maize and the rate of consumption surpasses its production. Apart from consumption, rice is a cash crop for smallholder farmers including those in Kirinyaga County. Despite its usefulness in contributing to food security, rice production has remained low due to various constraints. Among these are plant-parasitic nematodes (PPN) that account for up to 20% of yield losses. Other than the deleterious effect of PPN, rice agroecosystems contain free living nematodes (FLN) that play important ecological roles such as decomposition of organic matter and suppression of destructive PPN. However, through various cropping practices, the diversity and structure of the nematode communities is altered which affects crop productivity. This study examined the abundance and additively partitioned diversity of nematode communitiesin rice in Mwea. Soil samples were collected from 30 rice fields in Nyangati (15) and Tebere (15) in Mwea, Kirinyaga county. Nematode extraction was done using the modified Baermann technique before enumeration and identification to the genus level. To determine the differences in the abundance of nematode genera, one-way analysis of variance (ANOVA) was used. Spatial distribution of nematode communities in Nyangati and Tebere wasexamined using Jaccard index-based non-metric multidimensional scaling.One-way ANOVA was used to evaluate the differences in the indices and metabolic footprints in Nyangati and Tebere. Gamma diversity was additively partitioned into α and β components in the R package vegan.Turnover and nestedness components of beta diversity were computed using the betapart package in R software. The relationship between soil properties and nematode genera was evaluated using canonical correspondence analysis. There were 17 nematode genera in both regions with Aphelenchoides and Longidorus occurring in greater proportions in Tebere.The population of Helicotylenchus was high in Nyangati and Prodorylaimus occurred in high numbers in both regions.Aphelenchoides was positively correlated to electrical conductivity while Helicotylenchus was negatively correlated.The two regions could not be unequivocally ordered due to crossing of the Renyi diversity profiles along the scale parameter.Genus richness partitioning, showed that α and β components contributed 33.7% and 66.3% of the γ diversity, respectively.Partitioning of beta diversity showed that nestedness contributed to the overall nematode diversity observed in Nyangati and Tebere rice fields.Results obtained from this study provide information that could aid in development and implementation of effective and environmentally sound nematode management practices in rice.Item Food web structure of Nematode communities associated with rice in Mwea, Kenya(2023-07) Mokuah, DorcasNyabokeIn Kenya, rice is an important staple crop after wheat and maize and the rate of consumption surpasses its production. Apart from consumption, rice is a cash crop for smallholder farmers including those in Kirinyaga County. Despite its usefulness in contributing to food security, rice production has remained low due to various constraints. Among these are plant-parasitic nematodes (PPN) that account for up to 20% of yield losses. Other than the deleterious effect of PPN, rice agroecosystems contain free living nematodes (FLN) that play important ecological roles such as decomposition of organic matter and suppression of destructive PPN. However, through various cropping practices, the diversity and structure of the nematode communities is altered which affects crop productivity. This study examined the abundance and additively partitioned diversity of nematode communitiesin rice in Mwea. Soil samples were collected from 30 rice fields in Nyangati (15) and Tebere (15) in Mwea, Kirinyaga county. Nematode extraction was done using the modified Baermann technique before enumeration and identification to the genus level. To determine the differences in the abundance of nematode genera, one-way analysis of variance (ANOVA) was used. Spatial distribution of nematode communities in Nyangati and Tebere wasexamined using Jaccard index-based non-metric multidimensional scaling.One-way ANOVA was used to evaluate the differences in the indices and metabolic footprints in Nyangati and Tebere. Gamma diversity was additively partitioned into α and β components in the R package vegan.Turnover and nestedness components of beta diversity were computed using the betapart package in R software. The relationship between soil properties and nematode genera was evaluated using canonical correspondence analysis. There were 17 nematode genera in both regions with Aphelenchoides and Longidorus occurring in greater proportions in Tebere.The population of Helicotylenchus was high in Nyangati and Prodorylaimus occurred in high numbers in both regions.Aphelenchoides was positively correlated to electrical conductivity while Helicotylenchus was negatively correlated.The two regions could not be unequivocally ordered due to crossing of the Renyi diversity profiles along the scale parameter.Genus richness partitioning, showed that α and β components contributed 33.7% and 66.3% of the γ diversity, respectively.Partitioning of beta diversity showed that nestedness contributed to the overall nematode diversity observed in Nyangati and Tebere rice fields.Results obtained from this study provide information that could aid in development and implementation of effective and environmentally sound nematode management practices in rice.Item Food web structure of Nematode communities associated with rice in Mwea, Kenya(2023-07) Mokuah, DorcasNyabokeIn Kenya, rice is an important staple crop after wheat and maize and the rate of consumption surpasses its production. Apart from consumption, rice is a cash crop for smallholder farmers including those in Kirinyaga County. Despite its usefulness in contributing to food security, rice production has remained low due to various constraints. Among these are plant-parasitic nematodes (PPN) that account for up to 20% of yield losses. Other than the deleterious effect of PPN, rice agroecosystems contain free living nematodes (FLN) that play important ecological roles such as decomposition of organic matter and suppression of destructive PPN. However, through various cropping practices, the diversity and structure of the nematode communities is altered which affects crop productivity. This study examined the abundance and additively partitioned diversity of nematode communitiesin rice in Mwea. Soil samples were collected from 30 rice fields in Nyangati (15) and Tebere (15) in Mwea, Kirinyaga county. Nematode extraction was done using the modified Baermann technique before enumeration and identification to the genus level. To determine the differences in the abundance of nematode genera, one-way analysis of variance (ANOVA) was used. Spatial distribution of nematode communities in Nyangati and Tebere wasexamined using Jaccard index-based non-metric multidimensional scaling.One-way ANOVA was used to evaluate the differences in the indices and metabolic footprints in Nyangati and Tebere. Gamma diversity was additively partitioned into α and β components in the R package vegan.Turnover and nestedness components of beta diversity were computed using the betapart package in R software. The relationship between soil properties and nematode genera was evaluated using canonical correspondence analysis. There were 17 nematode genera in both regions with Aphelenchoides and Longidorus occurring in greater proportions in Tebere.The population of Helicotylenchus was high in Nyangati and Prodorylaimus occurred in high numbers in both regions.Aphelenchoides was positively correlated to electrical conductivity while Helicotylenchus was negatively correlated.The two regions could not be unequivocally ordered due to crossing of the Renyi diversity profiles along the scale parameter.Genus richness partitioning, showed that α and β components contributed 33.7% and 66.3% of the γ diversity, respectively.Partitioning of beta diversity showed that nestedness contributed to the overall nematode diversity observed in Nyangati and Tebere rice fields.Results obtained from this study provide information that could aid in development and implementation of effective and environmentally sound nematode management practices in riceItem Bacterial biological control agents in the management of bacterial wilt(curtobacterium Flaccumfaciens PV.Flaccumfaciens) in the common bean(UoEm, 2023-08) Munene, Lilian WanguiCommon beans (Phaseolus vulgaris) are widely grown throughout the world and provide valuable protein, vitamins and other nutrients. If the challenges related to its production are resolved, food security can be guaranteed for the growing population. Disease-causing pathogens are a major constraint in bean production. Curtobacterium flaccumfaciens pv. flaccumfaciens causes bacterial wilt of common bean disease. This pathogen causes high economic losses due to seedling death, yield loss and seed discoloration. Copper fungicides can reduce secondary spread but are expensive, harmful to the environment and lead to resistance of the pathogen. Bacterial control agents are effective and environmentally friendly alternatives to chemicals, as they provide protection throughout the crop period and are specific to plant diseases. However, less has been done in managing bacterial wilt using bacterial bio-controls. The objectives of this study were; to isolate wilt-causing pathogen in dry beans, to isolate bacterial antagonists against the pathogen from the rhizosphere of P. vulgaris and to control the pathogen in vitro and in vivo using the recovered bacterial bio-controls. The study was done in an experimental bean field located in Kimbimbi, Kirinyaga County. From infected leaves and seeds of bean plants, Curtobacterium species were isolated and characterized morphologically, biochemically, molecularly and by pathogenicity tests. Biological control agents were identified in the soil samples obtained from the rhizospheres of bean plants and screened against Curtobacterium flaccumfaciens using soft agar overlay assay. Primer pair 8F and 1492R were used for amplification of the 16S rRNA gene and sequencing. Analysis of the 16S rRNA gene was conducted to identify the Cff isolates and bacterial antagonists. Both a foliar spray and a seed treatment were used to apply bio-controls. A completely randomized design was employed for the experiment. Data on disease incidence and disease severity were analyzed using analysis of variance at a 95% confidence level. Phylogenetic analysis was done using the neighbor-joining method and phylogenetic tree constructed with MEGA software. Eleven Curtobacterium spp. were identified. Nine bacterial control agents showed antagonistic activities against Cff. A partial 16S rRNA gene sequence of these isolates identified species belonging to the genera Bacillus, Paenibacillus and Pseudomonas. Seed treatment coupled with foliar application of the antagonistic bacteria significantly reduced disease incidence and disease severity ranging from 16-29% and 4-10% respectively, compared to the control. Pseudomonas fluorescens was most successful in controlling the Cff pathogen with an efficacy of 81%, while B. cereus and P. polymyxa reduced the disease development by 79% and 68%, respectively. The use of rhizobacterial species provides a safe, effective and sustainable alternative to control bacterial wilt in the common bean. Herein, the rhizobacteria P. fluorescens, B. cereus and P. polymyxa species seed treatment coupled with foliar application significantly reduced the disease incidence and disease severity of bean bacterial wilt. The study recommends further research on distribution of bacterial wilt of common bean disease in bean-producing regions of Kenya and to determine if the isolated bacterial control agents are effective against other plant diseasesItem Food web structure of Nematode communities associated with rice in mwea,Kenya.(UoEm, 2023-07) Mokuah, Dorcas NyabokeIn Kenya, rice is an important staple crop after wheat and maize and the rate of consumption surpasses its production. Apart from consumption, rice is a cash crop for smallholder farmers including those in Kirinyaga County. Despite its usefulness in contributing to food security, rice production has remained low due to various constraints. Among these are plant-parasitic nematodes (PPN) that account for up to 20% of yield losses. Other than the deleterious effect of PPN, rice agroecosystems contain free living nematodes (FLN) that play important ecological roles such as decomposition of organic matter and suppression of destructive PPN. However, through various cropping practices, the diversity and structure of the nematode communities is altered which affects crop productivity. This study examined the abundance and additively partitioned diversity of nematode communitiesin rice in Mwea. Soil samples were collected from 30 rice fields in Nyangati (15) and Tebere (15) in Mwea, Kirinyaga county. Nematode extraction was done using the modified Baermann technique before enumeration and identification to the genus level. To determine the differences in the abundance of nematode genera, one-way analysis of variance (ANOVA) was used. Spatial distribution of nematode communities in Nyangati and Tebere wasexamined using Jaccard index-based non-metric multidimensional scaling.One-way ANOVA was used to evaluate the differences in the indices and metabolic footprints in Nyangati and Tebere. Gamma diversity was additively partitioned into α and β components in the R package vegan.Turnover and nestedness components of beta diversity were computed using the betapart package in R software. The relationship between soil properties and nematode genera was evaluated using canonical correspondence analysis. There were 17 nematode genera in both regions with Aphelenchoides and Longidorus occurring in greater proportions in Tebere.The population of Helicotylenchus was high in Nyangati and Prodorylaimus occurred in high numbers in both regions.Aphelenchoides was positively correlated to electrical conductivity while Helicotylenchus was negatively correlated.The two regions could not be unequivocally ordered due to crossing of the Renyi diversity profiles along the scale parameter.Genus richness partitioning, showed that α and β components contributed 33.7% and 66.3% of the γ diversity, respectively.Partitioning of beta diversity showed that nestedness contributed to the overall nematode diversity observed in Nyangati and Tebere rice fields.Results obtained from this study provide information that could aid in development and implementation of effective and environmentally sound nematode management practices in rice.Item Food web structure of Nematode communities associated with rice in mwea,Kenya.(UoEm, 2023-07) Mokuah, Dorcas NyabokeIn Kenya, rice is an important staple crop after wheat and maize and the rate of consumption surpasses its production. Apart from consumption, rice is a cash crop for smallholder farmers including those in Kirinyaga County. Despite its usefulness in contributing to food security, rice production has remained low due to various constraints. Among these are plant-parasitic nematodes (PPN) that account for up to 20% of yield losses. Other than the deleterious effect of PPN, rice agroecosystems contain free living nematodes (FLN) that play important ecological roles such as decomposition of organic matter and suppression of destructive PPN. However, through various cropping practices, the diversity and structure of the nematode communities is altered which affects crop productivity. This study examined the abundance and additively partitioned diversity of nematode communitiesin rice in Mwea. Soil samples were collected from 30 rice fields in Nyangati (15) and Tebere (15) in Mwea, Kirinyaga county. Nematode extraction was done using the modified Baermann technique before enumeration and identification to the genus level. To determine the differences in the abundance of nematode genera, one-way analysis of variance (ANOVA) was used. Spatial distribution of nematode communities in Nyangati and Tebere wasexamined using Jaccard index-based non-metric multidimensional scaling.One-way ANOVA was used to evaluate the differences in the indices and metabolic footprints in Nyangati and Tebere. Gamma diversity was additively partitioned into α and β components in the R package vegan.Turnover and nestedness components of beta diversity were computed using the betapart package in R software. The relationship between soil properties and nematode genera was evaluated using canonical correspondence analysis. There were 17 nematode genera in both regions with Aphelenchoides and Longidorus occurring in greater proportions in Tebere.The population of Helicotylenchus was high in Nyangati and Prodorylaimus occurred in high numbers in both regions.Aphelenchoides was positively correlated to electrical conductivity while Helicotylenchus was negatively correlated.The two regions could not be unequivocally ordered due to crossing of the Renyi diversity profiles along the scale parameter.Genus richness partitioning, showed that α and β components contributed 33.7% and 66.3% of the γ diversity, respectively.Partitioning of beta diversity showed that nestedness contributed to the overall nematode diversity observed in Nyangati and Tebere rice fields.Results obtained from this study provide information that could aid in development and implementation of effective and environmentally sound nematode management practices in rice.Item Value chain and unstainability of Mangrove Wood Harvesting In Lamu County, Kenya(UoEm, 2023-06) Riungu, Purity MuthoniMangrove forests provide harvestable wood and non-wood resources to human society around the world. The current study evaluated value chain of mangrove wood products from Lamu County, Kenya, and how these impacts on resources’ sustainability. To assess structure and yield data of Lamu mangroves, stratified random sampling design was used in the different blocks. Quadrats measuring 20 m × 20 m were established along transects, running perpendicular to the shoreline covering different vegetation types. Vegetation attributes measured included species, stem diameter (cm), height (m), and pole quality, from which the stand density (stems ha-1), stand table, basal area (m2 ha-1), and merchantable stems were derived. Rhizophora mucronata and Ceriops tagal had the highest stocking densities across the 5 management blocks. The density of merchantable poles for the dominant mangrove species’, Rhizophora mucronata and Ceriops tagal was estimated at 1,361stems ha-1. Results from the market survey show that exploitation of mangrove wood products in Kenya involve several actors, including the national regulator, licensees, cutters, transporters, stockists, and finally the consumers. Based on the differences between allowable and harvest data, Lamu mangroves can be said to be under-exploited. For the 1992-2018 period, an average of 223.5 scores ha-1yr-1 of mangrove poles were harvested from Lamu County. During the same period, the harvest data indicate that on averages, 6.2 scores ha-1 yr-1 of mangrove poles were removed. However, based on stand level data generated as part of this study, mangroves in Lamu County are over-exploited and stocked with non-merchantable poles. There are differentiated net income among various actors in mangrove trade in Kenya. Mangrove cutters are among the ‘least beneficiaries’ in mangrove trade value chain earning a monthly net income of USD118.6±17.9. The greatest winners in mangrove trade are the Kenya Forest Service, licensees, transporters, and mangrove dealers (or stockists) in urban centers. The findings of this study are critical in development of the harvesting plan for Lamu County mangroves. The results provide insights toward streamlining mangrove trade for community development, revenue generation and environmental sustainability.Item Molecular characterization of denitrifying Bacteria and their potential In reduction Of nitrogenous Compounds In Lake Victoria, Kenya(UoEm, 2023-06-19) Wachira, James MurimiNutrient loading with nitrogen and phosphorus in receiving waters is an increasing concern worldwide. In Lake Victoria basin, the substantial inflow of nutrients has led to extensive eutrophication which has resulted in the reiterative proliferation of invasive species of aquatic weeds like water hyacinth and cyanobacteria in the Lake Victoria basin hence causing mass mortality of fish and health risks. Nowadays, anthropogenic activities such as crop production, sewage discharge, fossil fuel combustion and fertilizer use have substantial intensified, therefore increasing the amount of nitrogen entering into terrestrial ecosystems. Heterotrophic nitrification and aerobic denitrification have been proposed as alternate strategies in nitrogen reduction in nitrogen-rich ecosystems. In this study, we examined the diversity of bacteria involved in nitrogen cycling and their potential application in bioremediation in Lake Victoria. Eight water samples were collected in triplicate using 500 ml sterile bottles and taken to SGS Kenya Limited Laboratory Services for physiochemical analysis. Total bacterial diversity in the collected samples was assessed using universal primers. Purified DNA (25 μl) was stabilized using DNAstable® (Biomatrica), air-dried, followed by Illumina sequencing. A culture dependent approach was used to recover aerobic denitrifiers using a medium with (NH4)2SO4 as the main N source in Bromothymol blue medium (BTB). Serial dilution was done and spread plated onto the BTB media followed by incubation. Single isolates were selected from the plates and sub-cultured in a similar media to obtain pure cultures. Screening for Nitrogen removal was done by inoculating single colony into screening medium containing (NH4)2SO4 as the main N source. Selected pure cultures were presumptively characterized based on molecular tests. Molecular characterization was achieved by extracting the DNA of positive isolate, amplifying 16S rRNA gene using universal primers (515F/806R), and sequencing. In order to determine how much nitrogen (N) was removed from effluent samples, 50 ml of sterilized wastewater was inoculated with a single colony and incubate at 30 °C for 120 hours and 150 rpm. Nitrogen removal by isolates was quantified using a spectrophotometer. Low absorbance indicated fewer molecules available to interact with the light, and vice versa. Physiochemical analysis showed there were elevated levels of total nitrogen and ammonia in both treated and untreated WWTPs as compared to lake and rivers samples. The sequence reads were grouped into 1,763 operational taxonomic units (OTUs). There OTUs were affiliated to 26 bacterial phyla with Proteobacteria being the most dominant phylum. Microbial diversity increased from WWTPs, rivers to lake. Isolated positive for nitrogen removal were recovered from the lake and WWTPs ecosystems and none from the river samples. The isolates were affiliated to genera Pseudomonas, Klebsiella, and Enterobacter in the phylum Proteobacteria. Klebsiella quasivariicola showed the highest utilization of nitrate and ammonium from the basal media as indicated by low absorbance values of 95.32% and 93.18%. The findings from this study show that bacteria play a very important role in removal of nitrogenous waste from waste water and some of them can be used in bioremediation efforts.Item Structural Variability Of Mangrove Forests along the Coast of Kenya(UoEm, 2023-08) Njiru, Derrick MuthomiMangrove forests occur across a diversity of coastal landforms with different geomorphological, climatic and oceanographic influences. These factors influence mangrove structural development and productivity and as a result, the structural development of mangroves varies with the coastal geomorphology. Earlier inventory studies in Kenya suggest that mangroves growing in north of the Tana River have different structural attributes from those growing south of the river. The current study characterised the structure and floristic composition of mangroves in Kenya by describing species composition, basal area (m2 ha-1), stem density (trees ha-1), importance value index complexity index and above ground biomass (Mg ha-1) across 14 sites spread across the coastline of Kenya. Variability in mangrove floristic composition was tested using analysis of similarities (ANOSIM) and the differences illustrated using non-metric multidimensional scaling (nMDS). Mangrove structural variability was tested using analysis of variance (ANOVA) and comparisons made by performing a post-hoc Tukey pairwise test. A hierarchical cluster analysis was then performed to determine the degree of similarity in mangrove species across the sites based on complexity index, biomass, tree diameter and tree height. To investigate the relationship between mangrove structure and possible drivers of variability, a regression fit model was used. The model described associations between mangrove standing biomass, environmental settings, precipitation, population density, and riverine influence across the sampled sites. Rhizophora mucronata was the most important species in most of the sites while Avicennia marina was the most important species in the estuarine area of Ungwana Bay. High values of structural complexity were observed in the estuarine and deltaic settings of Ngomeni and Kipini while relatively low levels of structural complexity were observed for the periurban mangroves of Mombasa and Mtwapa. Mangrove forest species composition differed significantly across the sampled sites (ANOSIM R: 0.24, p = 0.001). The mangroves of Kipini were significantly different from the rest of the sites. The study revealed significant differences in structural attributes of mangroves growing along the coast of Kenya, specifically, tree diameter [F (13, 34050) =163.01, p=0.000], tree height [F (13, 34050) =1827.28, p=0.000], basal area [F (13, 358) =5.45, p=0.000)], stand density [F (13, 358) =8.68, p=0.000], and standing biomass [F (13, 358) =15.36, p=0.000] across the sampled sites. Environmental settings and population density best explained the variability in mangrove standing biomass. The study suggests that the patterns of mangrove structural variability in Kenya closely follows the patterns of geomorphic variability along the coast. The study concluded that mangroves in Kenya are highly influenced by geomorphological and climatic variability along the coast as well as human influences. These findings are useful for mangrove managers and policy makers and have the potential to guide strategies and actions aimed towards sustainable management of mangrove forests in Kenya.