Masters Theses:Department of Biological Sciences
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Item The Effects of Herbivory on interactions of pollinators and flowers in Acacia SPP. (Fabaceae,mimosoideae) in Laikipia(Kenyatta University, 2005) Otieno, MarkAcacia trees are among the most dominant tree species found in semi arid ecosystems with a vast geographical distribution throughout the savanna habitats. The trees are leguminous and have remarkable ability to fix nitrogen in the soil, thereby, improving fertility. About all parts of an Acacia tree are edible to different types of animals and their leaves provide the only greenery in the dry season, so are bound to be eaten. As such, they support enormous pyramids of biomass in complex food chains with super predators at the apex. Economically, they are used as basic sources of fruits, firewood, medicine and secondary products for daily human livelihoods. Owing to their important, a lot of studies have focused on their growth ecology. Herbivory and reproduction are among the most studied aspects of Acacia. However, the interactive link between these two aspects and their effect on the growth success of Acacias is poorly understood. Understanding the link between herbivory and pollination, would not only provide useful information on the interaction of plants and diversity of visitors but also information on the floral morphometry and rewards to pollinators. The general objective of this study was to determine the effects of herbivory on interactions between pollinators and flowers in Acacia spp. The study was conducted at the Mpala Research Centre in Laikipia District of Kenya (0017'N, 36053'E) on one herbivore excluded plot (70m x 50m) and in the open grazed areas adjacent to the excusion plot. Acacia trees for investigation were randomly selected. Data were recorded on floral morphometric measurements and dehiscence in different browsing levels and simulated herbivory plots. The number and type of visitors to the flowers was also recorded besides determining the species diversity of wild flora within the study site. ANOVA was used to analyze variation in different flower attributes, SNKwas used to separate means with significant differences. Generally, unbrowsed trees produed significantly (P<0.05) more flowers, florets, anthers and larger floral diameters than naturally and heavilly browsed Acacia trees. Similarly, unbrowsed trees attracted more pollinators especially bees than naturally browsed trees. An earlier pollinator peak activity was recorded on unbrowsed trees than browsed trees. A significant shist of inflorescence dehiscence time occurred between unbrowsed and naturally browsed trees of A. nilotica, (KS=0.34, P<0.01), A. brevispica (KS=0.34, P<0.01) across the day. The unbrowsed trees attracted significantly more pollinators than naturally browsed trees probably because the unbrowsed trees had larger flowers thereby becoming more visible to pollinators from a distance than those of browsed trees. The delayed floral dehiscence of naturally browsed trees could have been caused by modification of the microclimate around the flowers making them open later in the day than unbrowsed trees. This study has shown than A. nilotica and A. brevispica vary their floral resources greatly when browsed, whereas A. etbaica tends to show compensatory floral growth. More studies therefore, need to be done on their reproductive success.Item Cytokine Levels and T cell Apoptosis Associated With Cerebral Malaria Immunopathology During Plasmodium berghei Anka Infection In A Mouse Model(2013) Mugweru, JuliusDuring the course of malaria infection, a range of pro- and anti-inflammatory cytokines are produced by the host immune system. Successful recovery from malaria involves striking a balance between these counteracting cytokines. The cytokine imbalance contributes to pathological features but their exact levels have not been elucidated. The present study aimed at investigating the role played by circulating cytokines in pathophysiology of cerebral malaria. Using an experimental cerebral malaria (ECM) model, the profile of five serum cytokines was determined by employing Cytometric Bead Assay. Seventy-two BALB/c mice (7-9 week/old) were intraperitoneally inoculated with approximately 1 x 105 parasitisized red blood cells at day 0 and randomized into six groups (six mice/group). Another set of noninfected mice was included to serve as control. The mice were sacrificed at day 4, 6, 8, 11 and 20 pi. The possible role of cytokines in inducing T-cell apoptosis associated with CM was investigated using the whole genomic DNA extracted from splenic and brain lymphocytes. Significantly higher systemic levels (P<0.05,) of IFN-γ (mean ±S.D 210.6±133, 169.8±80.5, 203.6±91.6, 22.0±3.5 pg/ml), were observed between day 8 and 20 p.i while TNF-α levels were significant at days 4, 8 11, 14 and 20 respectively (M ±S.D 2.9 ± 0.2, 33.9±17.5, 95.5 ±17.0, 22.1±3.6 pg/ml) in BALB/c mice that survived until day 20 pi with a higher parasitemia (up to 52.6%±0.8). Significant concentrations (P< 0.05), of IL-4 (M ±S.D 14.6±2.5, 10.6±1.9, 9.6±1.3 pg/ml) were observed between day 4 and 8 respectively but afterwards its levels remained low throughout the course of infection. IL-5 levels (M xix ±S.D 4.1±0.7, 3.4±1.6) had significant differences at day 11 and 20 pi. The study found IL-4 to be elevated between days 11 and 20 respectively with no significant differences (P>0.05) being reported. T-cell pathology was revealed by fragmentation of whole genomic DNA during the infection which coincided with elevated systemic pro-inflammatory (IFN-γ and TNF-α at day six) responses which further accelerated the severity of CM. The study demonstrated a parallel link between T-cell pathology and elevated levels of Th1 cytokines concentrations in the brain and the spleen. This study revealed that elevated levels of proinflammatory cytokines induce inflammation and cellular apoptosis inhibiting parasite clearance. Thus, interventions to regulate the Th1 cytokine responses may be beneficial in the prevention of severe CM. Further work is needed on IL-2 IL-10 and IL-12 cytokines that could be involved in the pathologyItem Genetic Diversity of Aphid Species Attacking Amaranth and Nightshades in Different Agro-Ecological Zones of Kenya and Tanzania(University of Embu, 2016-09) Kipnyargis, Alex C.Aphids are the major pests of vegetables leading to a significant yield loss in African indigenous vegetables including amaranth and nightshades. Information on the types of aphids that infest these vegetables and their genetic diversity in Kenya and Tanzania is scanty. This is an important diagnostic component in developing management strategies such as integrated pest management and early detection and control of invasive species. This study used a fragment of the mitochondrial cytochrome c oxidase subunit I (COI) gene region called the barcode region to characterize the species of aphids that attack amaranth and nightshades in different agro-ecological regions of Kenya and Tanzania. Individual aphid samples were collected in 22 localities of amaranth and nightshade growing zones of the two countries, representing low, mid and high altitude agro-ecological zones. Total DNA was isolated and amplified using universal barcoding primers targeting the 5’ end of the COI barcode region. There was a strong homology (≥ 98% identity) in nucleotide sequences of the barcode region using the Basic Local Alignment Search tool for nucleotides (BLASTn) in the GenBank to four main species of aphids namely: Myzus persicae, Aphis fabae, Aphis craccivora and Macrosiphum euphorbiae. Further, three subspecies of the black bean aphid were identified as A. fabae fabae, A. fabae ciirciacanthoidis and A. fabae solanella. Intra-specific nucleotide diversity indicated that M. euphorbiae had no genetic diversity (0.0%); while A. fabae had the highest diversity (0.8%). The lowest inter-specific diversity was observed between A. fabae and A. craccivora (6.3%) while the highest was observed between A. craccivora and M. persicase (10.6%). The phylogenetic tree constructed using the maximum likelihood model showed each individual species clustering in robust clades irrespective of the host crop or the locality from which it was collected. This confirmed the BLASTn results. The principal coordinate analysis (PCoA) and the haplotype network analyses further confirmed these results by showing species clustering together in their space and haplotypes, respectively. Overall, COI successfully identified the species of aphid infesting amaranth and nightshades. This forms an important diagnostic tool for management strategies, early detection of newly evolving biotypes, deployment of resistant crop cultivars and containment of invasive species.Item Competence of Tropical Maize Lines to Agrobacterium-Mediated Transformation and the Expression of Maize Poly (ADP-Ribose) Polymerase (PARP2) Gene under Drought Stress.(Kenyatta University, 2017) Muli, Joshua K.Drought stress affects many maize growing regions in sub-Saharan Africa. As population increases, the gap between maize supply and demand increases. There is, therefore, need to develop maize lines that are tolerant to drought as well as amiable to Agrobacterium-mediated transformation. This study aimed to assess the competence of tropical maize lines after co-cultivation on Yeats Extract Peptone (YEP) media to Agrobacterium-mediated transformation and determine the relative expression of PARP2 gene under drought during development. Tropical inbred maize lines CML 144, CML 216, A04, and E04 as well as Agrobacterium strain EHA101 harboring vector pTF102 containing the GUS reporter gene were used in this study. The ability of immature maize embryos to form embryogenic calli was determined after pre-culturing these embryos on YEP and Murashige and Skoog (MS) media. Transient GUS assay was used to evaluate the competence of the inbred maize lines to Agrobacterium-mediated transformation using YEP as co-cultivation media or YEP that was supplemented with growth regulator 2,4-D (YEP+2,4-D), Cysteine (YEP+CYS), Proline (YEP+PRO) or in combination (YEP+ALL). In all cases, MS media was used as the control. The optimum Agrobacterium concentration for infection of immature maize embryos before co-cultivation was determined. The physiological response of tropical maize lines to drought stress was evaluated and the expression of the PARP2 gene at different drought levels determined by Polymerase chain reaction (PCR). The data collected was analysed using ANOVA at 95% confidence interval with SAS statistical computer software (version 9.1.3). Separation of means was carried out using Tukey’s pairwise comparison at 5% probability level. Callus formation frequency and regeneration were genotype dependent (P= 0.0001). Immature embryos from the four inbred maize lines exhibited high transient GUS expression when co-cultivated with Agrobacterium on YEP (12.31%), YEP+PRO (13.75%) and YEP+ALL (8.68%) media than when cocultivated on MS media (6.76%). Co cultivation in YEP+2,4-D and YEP+CYS, however, resulted in lower transient GUS expression than on MS media. Agrobacterium tumefaciens at a concentration of 0.07 (OD660) gave the highest transient GUS expression (20.90%) while higher concentrations of 0.2 and 0.8 resulted in low transient GUS expression (9.17% and 12.22%), suggesting that YEP media is superior to MS media in enhancing the competence of immature embryos to Agrobacterium-mediated transformation. Thus YEP media is proposed as an alternative media in in Agrobacterium-mediated transformation protocols. Growth rate, fresh weights of seedlings and dry weights of seedlings was low in seedlings subjected to severe drought stress compared to seedlings subjected to moderate drought and unstressed conditions. Severe and moderate drought stresses induced the expression of maize PARP2 gene, suggesting that deregulation of maize PARP2 gene is likely to improve the ability of tropical maize to resist severe drought stress condition.Item Phytoplankton Composition, Growth Rates and Oil Production Potential of Fast Growing Species from Lake Naivasha and Water Reservoirs at Embu University College(University of Embu, 2017-01) Musyoka, Sammy M.The demand for non-renewable fossil fuel has greatly increased in the last few years from 84 million barrels of fossil fuel per day in 1980’s to over 100 million barrels per day in 1990. To supplement this demand, research on alternative sources has been going on since 1960’s in different parts of the world. Among the alternative sources, the phytoplanktons have shown great promise due to their high oil yield in comparison to energy crops. In Kenya, despite the occurrence of highly productive eutrophic lakes, no research has been carried out to assess the potential of phytoplankton species in oil production. This study therefore aimed at identifying and assessing the oil production potential of fast growing phytoplankton species in a species rich natural freshwater lake (Lake Naivasha) and man-made reservoirs at Embu University College. Data was collected from December 2014 to May 2015. During each sampling trip, selected physico-chemical parameters were measured and water samples collected for analysis of nutrients as well as species identification, composition, isolation and culturing in the laboratory. The samples were inoculated in phytoplankton growth media and cultured under 14:10 light: dark photoperiod. The fast growing species were identified through screening the biomass accumulated. These species were then cultured for lipid extraction. Results on physico-chemical characteristics revealed that, inflows during the wet months (December 2014 and April 2015) resulted in low Secchi depth, conductivity and total alkalinity. Highest values were recorded during the dry month of February 2015. High values of pH (8.6 both in lake Naivasha and EUC dams were recorded). High total nitrogen (TN range =0.18-0.271 mg L-1 in Lake Naivasha and 0.091-0.097 in EUC dams) and total phosphorous (TP range =0.069-0.093 mg L-1 in Lake Naivasha and 0.004-0.073 in EUC dams) ranges were recorded during the wet months. Results showed that phytoplankton species composition consisted of a total of 134 species in Lake Naivasha and 122 species in EUC reservoirs. Species diversities ranged from 1.29 to 1.68 with Lake Naivasha registering a mean of 1.5 which was not significantly different (p < 0.158) from the mean of 1.44 in EUC Dams. The fastest growing phytoplankton species in both Lake Naivasha and EUC reservoirs included; Closteriopsis acicularis (0.64 mg L-1 d-1), Chlorella saccharophilla (0.53 mg L-1 d-1), Chlorella vulgaris (0.49 mg L-1 d-1), Cosmarium contractum (0.42 mg L-1 d-1) and Scenedesmus ellipticus (0.37 mg L-1 d-1). Oil production potential recorded by Nannochloropsis sp, Chlorella saccharophilla, Chlorella vulgaris and Scenedesmus ellipticus was 30%, 10.8%, 8.7% and 5.4% respectively. The results also showed that mean oil produced by phytoplankton isolates from Lake Naivasha and EUC reservoirs did not differ significantly(p< 0.05). The findings of phytoplankton species from Lake Naivasha and EUC reservoirs having oil production potential opens an opportunity for discussion and further research on how to incoporate recent technology in phytoplankton biofuel production to offer a solution to the experienced energy crisis.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 Drought prevalence in the horn of Africa and its implications on forest cover: a Case Study of Somalia(University of Embu, 2020-11) Musei Kipngeno, SylusSomalia is one of the most drought prone countries in Africa. Drought is the country’s costliest natural disaster. The impact of drought events on the economy, on people`s livelihoods and on lives has grown. Drought events usually develop gradually unnoticed, causing tremendous effects on both agriculture and environment. This study evaluated the spatio-temporal variations of drought occurrences in Somalia and its implication on forest cover. In this study, precipitation and temperature variables were taken as a proxy to assess and quantify long-term drought in Somalia. The intensities, frequencies and trends of drought occurrences were analyzed using Standardized Precipitation Evapotranspiration Index for the multiple timescales of 1-, 3-, 6-, 12-, and 24-month. Drought maps were done using Normalized Difference Vegetation Index during the period 1982 to 2015. Hansen data was used to account for forest cover change whereas a sample of 20 papers were reviewed in order to determine the best fit land degradation mitigation measures. Temporal variations in drought showed decreasing trends in severity and increasing trends in drought duration as the SPEI timescales increased. The major drought event as identified by SPEI 12 occurred during the period between May 2011 and January 2013, lasting for a period of 12months with an intensity of -0.55. Furthermore, drought count was generally high in the southern parts of Somalia and entire country had suffered droughts ranging from moderately dry to severely dry conditions. An average drought duration of between 2 and 3 months was recorded for most (81%) of the locations. About 23 % of forest cover was lost from 79,294 ha to 67,199ha from 2000 to 2019 representing a loss of 1,058ha per year. The study findings show the need for immediate actions to tackle drought and hence poverty and famine in Somalia. A combination of remote sensing tools conservation practices (such as agroforestry, afforestation, reforestation and conservation agriculture) is ideal for monitoring and mitigating land degradation effects respectively.Item Bioprospecting for Cyanophages with Biocontrol Potential against Toxin Producing Cyanobacteria in Lake Magadi, Kenya(University of Embu, 2020-11) Kihagi Ngetha, EdwinCyanobacteria are a phylum of blue-green algae in the domain bacteria that get their energy from sun light through photosynthesis. In anaerobic environments, photoautotrophic blue green algae derive electrons by reduction of sulphur. In the Kenyan soda lakes, cyanobacteria serve as the sole source of food for Lesser Flamingos. Also, detection of these blue green algae blooms, is evident in these environments. Due to this reason, it has been hypothesized that the blooms may lead to production of secondary metabolites referred to as cyanotoxins that could be the cause for mass mortalities of Lesser Flamingos in these lakes including Lake Magadi. Viruses are key in controlling microbial populations in any ecosystem and thus they could act as a biocontrol measure for toxin producing cyanobacteria. Therefore, this study aimed to isolate cyanobacteria, amplify for toxin production genes and screen for cyanophages that can control these toxin producing cyanobacteria. The study site was Lake Magadi in the Rift Valley which has highly alkaline pH (8-12). Water samples were collected from different points around Lake Magadi. Physiochemical variables such as pH, salinity and temperature were measured for each of the sample on site. Two techniques for the isolation of cyanobacteria were used: isolation by spread plating on agar and dilution to extinction technique. Five types of media were used: Blue green medium (BG11), Synechococcus medium (A+), artificial lake water medium (ALW), artificial sea water medium (ASW) and enriched lake water medium (M). For solid cultures, spread plating was done followed by subsequent sub-culturing to acquire axenic cultures. Dilution to extinction technique involved subsequent dilution of the enriched sample until an axenic culture was obtained. These isolates grew at conditions that are unique to haloalkaliphiles. The cyanobacteria were subjected to morphological and molecular identification. Molecular identification involved partial sequencing of 16Sr RNA gene. Potential of the isolates to produce cyanotoxins was assessed by amplification of their respective genes using toxin specific primers. Sequence analysis indicated that all 11 isolates were affiliated to Cyanobacterium Spp. Genera represented include Spirulina, Synechococcus, Oscillatoria and Anabaenopsis. PCR amplification showed that all the isolates had different genes for toxin production. Phage lysis was observed in 10 of the isolates indicating that they were hosts for the phages. This study provides an insight into the uncultured cyanobacterial species from extreme environments and their cyanophages. The recovered isolates are a useful resource in understanding the taxonomy, phylogeny and diversity of cyanobacteria as well as their cyanophages. The cyanophages can be useful in biotechnology application for biocontrol of toxin producing cyanophages.Item Drought Prevalence in the Horn of Africa and Its Implications on Forest Cover: A Case Study Of Somalia(University of Embu, 2020-12-11) Kipngeno, Sylus MuseiSomalia is one of the most drought prone countries in Africa. Drought is the country’s costliest natural disaster. The impact of drought events on the economy, on people`s livelihoods and on lives has grown. Drought events usually develop gradually unnoticed, causing tremendous effects on both agriculture and environment. This study evaluated the spatio-temporal variations of drought occurrences in Somalia and its implication on forest cover. In this study, precipitation and temperature variables were taken as a proxy to assess and quantify long-term drought in Somalia. The intensities, frequencies and trends of drought occurrences were analyzed using Standardized Precipitation Evapotranspiration Index for the multiple timescales of 1-, 3-, 6-, 12-, and 24-month. Drought maps were done using Normalized Difference Vegetation Index during the period 1982 to 2015. Hansen data was used to account for forest cover change whereas a sample of 20 papers were reviewed in order to determine the best fit land degradation mitigation measures. Temporal variations in drought showed decreasing trends in severity and increasing trends in drought duration as the SPEI timescales increased. The major drought event as identified by SPEI 12 occurred during the period between May 2011 and January 2013, lasting for a period of 12months with an intensity of -0.55. Furthermore, drought count was generally high in the southern parts of Somalia and entire country had suffered droughts ranging from moderately dry to severely dry conditions. An average drought duration of between 2 and 3 months was recorded for most (81%) of the locations. About 23 % of forest cover was lost from 79,294 ha to 67,199ha from 2000 to 2019 representing a loss of 1,058ha per year. The study findings show the need for immediate actions to tackle drought and hence poverty and famine in Somalia. A combination of remote sensing tools conservation practices (such as agroforestry, afforestation, reforestation and conservation agriculture) is ideal for monitoring and mitigating land degradation effects respectively.Item Anti-Cancer and Anti-Inflammatory Secondary Metabolites of Fagaropsis Angolensis (Engl.) H.M. Gardner(University of Embu, 2020-12-11) Wambua, Mukavi JustusCancer has become a key public health affliction worldwide. Recent studies have shown that genetic factors cause only 5–10% of all human cancers, while the rest are caused by lifestyle. Epidemiological and clinical studies have shown that chronic inflammatory diseases predispose individuals to various types of cancer. An estimated 20 % of all cancer related deaths globally arise from primary infections and inflammation. Current treatments for cancer include radiotherapy, chemotherapy, surgery, hormone, immune and targeted therapies. However, the efficacy of these treatments is constrained by their unexpected detrimental effects on other non-target tissues, development of multi-drug resistant cancer cell lines and high cost. Medicinal plants are increasingly attracting attention of researchers as a source of complementary and alternative therapies to mitigate cancer morbidity and mortality. Plants have been reported to contain bioactive phytochemicals with anti-infective properties against chronic diseases, including inflammation and cancer. In the current study the air-dried roots bark and leaves of Fagaropsis angolensis were pulverized into fine powders. The plant materials were then exhaustively extracted with 50% CH3OH in CH2Cl2 (v/v) at room temperature by cold solvent percolation. Separation was carried out using column chromatography on silica gel as the stationary matrix and eluted with gradients of n-hexane, EtOAc and MeOH. The resultant fractions were then purified using finer silica gel by recurrent column chromatography, Sephadex LH 20 and Chromatotron to afford a total of five compounds including two new norhopane derivatives; 3β,6β,22-trihydroxy-7β,11α-di[(4-hydroxybenzoyl)oxy]21αH-24-norhopa-4(23)-ene (42) and 3β,6β,22-trihydroxy-7β-[(4- hydroxybenzoyl)oxy]-21αH-24-norhopa-4(23)-ene (43) together with the known norhopane, 3β,6β,11α-trihydroxy-7β-[(4-hydroxybenzoyl)oxy]-24-norhopa- 4(23),17(21)-diene (44) and a norneohopane, (21α-H)-24-norneohopa-4(23), 22(29)diene-3β,6β,7β-triol 7-caffeate (30) from the root bark. The leaves afforded a reported flavone, tachrosin (45). Their structure elucidation was achieved by detailed 1D and 2D NMR, HRESI-MS, FT-IR and UV spectra for the newly described compounds and by comparison of these data with those of correlated compounds in the published literature. Resazurin reduction assay was used to evaluate the cytotoxicity of compound 46, with doxorubicin as reference anticancer drug. Compound 46 displayed minimal activity since the cell viability was more than 70 % against drug sensitive CCRF-CEM. Owing to the risk associated with chronic inflammation to initiation, promotion and progression of carcinogenesis, compounds 42 – 45 were assessed for their anti-inflammatory activity by quantifying the levels of cytokines Interleukin-1β (IL-1β), Interleukin-2 (IL-2), Granulocyte-macrophage colony-stimulating factor (GM-CSF) and Tumor necrosis factor-alpha (TNF-α) in lipopolysaccharide (LPS) stimulated peripheral blood mononuclear cells (PBMCs). All tested compounds decreased secretion of IL-1β and TNF-α. Compounds 43 and 45 clearly decreased secretion of IL-2, GM-CSF and TNF-α in comparison with the reference drug ibuprofen. The findings from this study revealed that F. angolensis contains significant amounts of hopane-type triterpenoid derivatives with potential to downregulate pro-inflammatory biomarkers and further provide a scientific rationale for using the plant in Kenyan folk medicine as anti-pain solution.Item Microbial Community Diversity and Structure within Organic and Conventional Farming Systems in Central Highlands of Kenya(University of Embu, 2020-12-11) Karanja, EdwardMicrobial diversity and function in agro-ecosystems is influenced by various aspects linked to soil and agronomic practices for example, tillage, irrigation, crop rotation and application of organic and inorganic inputs. Farming systems practices may affect the dynamic interactions existing between soil, plant and microorganisms in different agricultural biomes. Due to limitations associated with conventional microbial cultivation strategies, only a fractional number of cultivable species has been extensively studied. This study explored the effects of conventional versus organic farming systems on microbial communities. Soil samples were collected from an ongoing long-term farming system comparison trials established in 2007 at Chuka and Thika in Kenya. Illumina sequencing technology and analysis of 16S rDNA, 16S rRNA cDNA amplicons, fungal ITS and mRNA transcripts were used to determine the diversity, structure and function of bacteria, archaea and fungal communities within conventional and organic farming systems. Grouping of sequences into operational taxonomic units at 97% similarity was done using QIIME2 pipeline and taxonomy assigned via BLASTn against SILVA 128 and UNITE ITS database, and a curated database extracted from GreenGenes, RDPII and NCBI. Transcriptomes were analysed using Parkinson lab pipeline (https://github.com/ParkinsonLab/Metatranscriptome-Workshop). Statistical analysis was done using R programming language version 3.1.5 and Vegan Community Ecology Package version 2.5.2. R. The total number of OTUs obtained per dataset included 4,916 OTUs (16S rDNA), 530 OTUs (16S rRNA cDNA) and 1,128 OTUs (fungal ITS) at 97% genetic distance datasets, respectively. The most notable bacterial phyla within farming systems were Proteobacteria, Actinobacteria, Firmicutes Acidobacteria, Bacteroidetes, Chloroflexi, Cyanobacteria, Deinococcus-Thermus, Fusobacteria, Gemmatimonadetes, Planctomycetes and Verrucomicrobia. Farming systems in both sites were dominated by unassigned fungal phyla. The known fungal phyla revealed included Ascomycota, Basidiomycota, Chytridiomycota, Glomeromycota, Calcarisporiellomycota, Kickxellomycota and Mortierellomycota. Ascomycota was most abundant in organic farming systems while Chytridiomycota was dominant in conventional farming systems in both sites. Conventional farming systems had a higher species richness and diversity when compared with organic farming systems. Factors such as pH, C, N, Zn, Fe, Al, B and micro-aggregates were found to be the major drivers of microbial diversity within farming systems in both sites. Major metabolic pathways within the farming systems in both sites comprised of carbohydrates and energy metabolism, biodegradation and metabolism of xenobiotics and secondary metabolites biosynthesis. This shows that microbes in the farming systems utilize diverse carbon sources for survival, as revealed by metabolic processes and genes responsible for specific pathways. These findings indicate integration of organic and inorganic inputs, not only affect the soil chemistry but also the microbial population dynamics and their functional roles.Item Diversity and Biological Control Potential of Haloalkaliphilic Fungi from Lake Magadi, Kenya(University of Embu, 2020-12-11) Orwa, PhilemonFungi are eukaryotic microorganisms that have simple multicellular or unicellular cell structures. They are distributed in terrestrial soils, forests, aquatic habitats and in extreme environments with high ambient salts, temperature, pH and pressure. Fungi from extreme environments are potential sources of novel biocatalysts for example antimicrobial agents that can help solve the rising cases of drug resistance. However, the diversity of fungi recovered and described from less studied environments such as the soda lakes is quite low as compared to the soil ecosystem. Very few haloalkaliphic fungi have been recovered from hypersaline environments. In this study, we explored the cultivable fungal diversity in Lake Magadi and their ability to produce secondary metabolites. Dilution plate technique was used to isolate fungi from soda lake soils using alkaline media (Potato dextrose agar, Malt extract agar, Oatmeal agar and Sabouraud dextrose agar) prepared using sterilized lake water from the lake. Unique isolates were selected based on morphological features and subjected to physiological tests to determine their ability to grow at different pH, temperature and salts ranges. Molecular characterization was done by analysis (BLAST) of the amplified conserved regions of 18SrDNA followed by phylogeny. Ability of the isolates to utilize different carbon sources was tested on media supplemented with different substrates (starch, cellulose, casein, lignin, pectin, xanthan, chitin, Tween 20). Antimicrobial screening was done using both crude and cell free extracts to determine the ability of the isolates to produce metabolites (comparison of mean diameter of inhibition zones) that can be used to control both human pathogens and agricultural pathogens. The test pathogens included human pathogens Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Salmonella spp., Shigella spp. and Candida albicans which were laboratory isolates and plant pathogens Epicoccum sorghinum strain JME-11, Alternaria tenuissima, Didymella glomerata, Schizophyllum commune isolate ScGD28, Phoma destructiva, Cladosporium halotolerans CBS 119416, Aspergillus fumigatus EG11-4 and Dickeya dianthicola (field isolates). In total, 52 isolates were recovered from the study having different pigmentations. Their physiology depicted actual characteristic of haloalkaliphilic environments as the fungi tolerated extreme pH of up to 10 and salts (15-20%) and some grew at 35-40ºC. Sequence analysis indicated that the isolates were affiliated to 18 different genera with Aspergillus, Penicillium, Phoma, Cladosporium, and Acremonium. Substrate utilization tests showed that the different isolates produced proteases, chitinases, cellulases, amylases, pectinases and lipases. Isolates 2M, 59M, 69M, 87M, 100M, 111M and 113M were outstanding as they produced more than four enzymes. Results from the antimicrobial screening showed one isolate (11M from Site 3 soil) with 99% affiliation to Penicillium chrysogenum CBS 306.48 was able to inhibit major enteric bacteria and plant pathogenic fungi. Similar studies on saline environments have reported the phylum Ascomycota as the dominant fungal group and all the genera recovered in this study are classified in the same phylum. Antimicrobial from the fungal isolates provide a basis for pharmacological research since they can further be purified to obtain compounds that can be used as antibiotics or biopesticide against human and plant pathogens respectively. This can provide a solution to the rising problem of antibiotic resistance and pesticide resistance.Item Response of Spk 004 to Meloidogyne Species Infestation and Impact of Sweet Potato Management Practices on Nematofauna in Mwea, Kenya(University of Embu, 2020-12-11) Hellen, MainaSweet potato (Ipomoea batatas L.) is an important food crop consumed throughout Africa. However, sweet potato yields are greatly reduced by pests including plant parasitic nematodes. Management of nematodes in sweet potato fields in Kenya has mainly been through the use of nematicides and crop rotation which have limitations. The use of resistant sweet potato cultivars along with other low-cost organic amendments is the most economical, effective, and environmentally safe method of managing root-knot nematodes (RKN) in sweet potato fields. This study sought to evaluate the impact of sweet potato management practices on the population dynamics and diversity of plant parasitic (PPN) and free-living (FLN) nematodes. Field performance of the sweet potato cultivar, SPK 004, which was previously selected as RKN resistant under greenhouse conditions was also assessed. In determining the effect of low-cost management strategies on PPN and FLN, field experiments were established in a randomized complete block design involving four treatments and un-amended controls during long rains (March – July 2018) and short rains (October – February 2019). Soil samples were collected monthly for four months. Nematodes were then extracted and identified to the genus level. Forty-seven nematode genera belonging to five trophic groups were identified. Goat manure had the most pronounced effects on PPN of economic importance in sweet potato. All treatments revealed a low diversity of predatory nematodes. There were differences in metabolic footprints, ecological and functional indices during the LR, and SR. Plots amended with cow manure had significantly high predator and omnivore footprints during long and short rains seasons, respectively. Functional metabolic footprints categorized all plots as degraded in both seasons except in maize - sweet potato intercrop which was structured in short rains season. However, plots amended with goat manure bordered a structured ecosystem in LR while cow manure plots bordered a structured ecosystem in both seasons. A high diversity of freeliving nematodes was observed in this study, with all treatments having a significantly high density of bacterivorous nematodes. Goat manure treatment was more effective in increasing the populations of free-living nematodes. To evaluate the field performance of SPK 004 in response to Meloidogyne species, trials were conducted in Mwea, Kenya for two seasons. Experimental plots were laid out in a randomized complete block design involving two treatments; plots planted with SPK 004 and plots planted with SPK 004 and treated with a nematicide. Soil samples were collected before planting and during harvest to determine the initial and final RKN population. Root samples obtained at harvest were rated visually for resistance using a galling index. Data were subjected to analysis of variance to determine differences in Meloidogyne populations, dry matter content, and yields between the treatments. There were no significant differences in SPK 004 resistance between the two treatments. However, plots planted with SPK 004 and treated with nematicide recorded significantly higher nematode populations in the short rains season. Findings from this study confirmed greenhouse results, where this cultivar was found to be very resistant to Meloidogyne incognita. This resistant cultivar may be used in nematode infested fields for the management of RKN. Goat manure may be incorporated as a relatively low-cost nematode management strategy and also as a stimulant of beneficial free-living nematodes.Item Mitigation of Crop-Raiding Wild Boars in Selected Counties in Sweden: Assessing Feasibility of Electric Fences and Supplementary Feeding(University of Embu, 2022-04-06) Muchoka, Cecilia M.Wild boar (Sus scrofa) is a wild Suidae native in Europe, North West Africa and Asia. The population of wild boar has drastically increased during the last threedecades in Southern and Central Sweden. This increase in population density has caused severe damages to agricultural fields thus affecting the agricultural economy.There has been a significant loss of wheat, worth over 60 - 70 million Euros between1990 - 2016 due to crop damage by wild boar. This study sought to investigate the effectiveness of electric fencing and supplementary feeding as mitigation measures to crop-raiding of wheat fields by wild boar in South-Central Sweden. The study was carried out in five study sites in Sweden; Koberg, Boo, Bornsjön, Mörkö, and Grimsö. To achieveobjectives one and two, a total of eleven adult wild boar were marked with GPS/GSM-collars in 4 study sites (Koberg, Boo, Mörkö, and Grimsö), and monitoring of crop and habitat selection was performed using GPS units. Data fromthe marked animals was logged in every one hour and then transmitted through the GSM network every seventh hour by SMS to a computer server. Further, a total of 131 feeding stations were used to determine the effectiveness of supplementary food.Objective three, had Boo, Bornsjön, and Mörkö sites experimental wheat fields, i.e., 12 fields with electric fences, and 12 without fences. The fences were constructed by wooden poles in all corners of the field and with small plastic poles in between, and ringed with three metal wires at 20cm, 40cm, and 60 cm high from the ground and supplied with a 12-volt battery. GLMM models in R software (version 3.6.2) and Q GIS (version 3.10.2) were used for the data analysis. Results indicated that wild boar had a high preference for clear-cuts, agricultural fields, anddeciduous forests. The marked animals showed a high preference for crop fields withoat, spring wheat, and mixed crops. A binary logistic model revealed a significant influence of distance to feeding stations on the selection of different habitats and crop fields with both positive and negative effects. Generally, feeding stations influenced the selection of different habitats and crops negatively i.e., the closer a habitat or crop field is to a feeding station, the higher the likelihood of its selection. Besides, distance to main roads significantly influenced the selection of habitats and crop fields with both positive and negative effects. The paired t-test analysis was conducted in R-studio to compare mean harvest yield, pre-harvest damage (< 1 month) and, growing season damage (from sowing period to < 1-month pre-harvest)between electrically fenced fields and unfenced fields. Significant differences in thepre-harvest damaged area were found between the electric fenced and unfenced wheat fields in two of the three study sites. Further, there was an inverse relation between damage size and mean yield in the fenced fields. The gross margin results found that supplementary feeding was effective in preventing wild boar from farmlands. In conclusion, distance to feeding station and main road influenced wild boar selection of different habitat and crop fields differently. Also, the electric fences installed were effective in reducing wild boar damages on the wheat fields. The study recommends farmers and landowners to use electric fences as a way of reducing wild boar damages to their agricultural fields.Item Influence Of Drought On Interactions Among Aphids, Aphid Predators And Fusarium Infection On Barley Crop In Sweden(University of Embu, 2022-09-20) NJUE, MARTIN MUCHANGIClimate-change leads to extreme droughts, but it is difficult to predict how crop pests are affected. Drought may alter behavior of crop pests such as aphids that facilitate transmission of pathogens like Fusarium graminearum, causing Fusarium foot and root rot in barley crops by feeding close to the susceptible base of plants. Ground dwelling generalist predators like Carabid beetles, and wolf spiders are important aphid enemies during the aphid colonization phase in barley crops in Sweden. This study sought to determine the influence of drought on interactions among aphids, aphid predators, and Fusarium infections on spring sown barley (Hordeum vulgare L.) in Sweden. To evaluate the influence of drought on predation of aphids by Carabid beetles and Wolf spiders, the experimental design used was factorial with two factors, i) drought and no drought, ii) predators present and predators absent. Similarly, the experimental design used to assess the influence of drought on interactions between aphids and Fusarium infections on barley sown during spring was factorial with three factors, i) drought and no drought, ii) aphids and with no aphids, iii) Fusarium and with no Fusarium. To evaluate the influence of drought on predation of aphids by Carabid beetles and Wolf spiders, the total number of aphids per cage and the proportion of aphids present on different parts of each barley plant sampled (below ground, 0-1 cm above ground, >1cm above ground on stem, and on the leaves) was recorded. Data was subjected to normality test to determine its distribution and analyzed using generalized linear mixed effects models with the lme function in the nlme package in R 3.4.2. To assess the influence of drought on interactions between aphids and Fusarium infections, the total number of aphids present at 0-1 cm above ground, >1cm above ground on stem, and on the leaves per plant in each pot was recorded. The data was subjected to normality test and analyzed using generalized linear mixed effects models with the lme function in the nlme package in R 3.4.2. Disease scores on the barley inoculated with Fusarium were recorded and the data analyzed using one-way ANOVA test. There was a significant effect of Fusarium inoculation on barley plants. In addition, Fusarium significantly reduced the number of aphids on the whole plant and 0 to 1 cm above the ground. The study concluded that drought increased proportion of aphids (Rhopalosiphum padi L.) below ground. In addition, a strong effect of predation by Carabid beetles and Wolf spiders reduced the number and proportions of these aphids below ground only in dry conditions. This study recommends the need for further studies to establish how drought intensity is likely to affect interactions among pest populations, their natural enemies and plant pathogens.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 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 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 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.