Theses and Dissertations Collection
Permanent URI for this collectionhttp://10.10.97.169:4000/handle/123456789/3400
Browse
Recent Submissions
Item Analyzing aspects of land-use sustainability in Tanzania: Current forest degradation, urban charcoal demand, and impacts of future firewood and charcoal consumption(Norwegian University of Life Sciences, 2019) Nyamoga, Greyson ZabronThe forest sector plays a significant roles both directly and indirectly in Tanzania. In total 54% of the land area of mainland Tanzania is covered by different types of forests, the main ones being the miombo woodlands, woodland mosaics, mangrove and the tropical or rain forests with closed canopy. Forestry supports directly or indirectly other sectors including agriculture and tourism through provision of habitats for wildlife, water resources and catchments as well as maintaining hydrological balance and soil protection. It plays significant roles in biodiversity protection and recycling atmospheric gases, and provides construction materials, income and employment opportunities. 7’anzania’s wood harvest volume is difficult to estimate, but according to FAO official statistics the country’s total annual harvest of wood in 2014 was about 40 mill m3 of which more than 93% was used for firewood or charcoal production. In Tanzania, more than 90% of the population use fuelwood (i.e. charcoal and firewood) as main source of energy. Most of this fuelwood is supplied from the miombo woodlands which covers about half of the forest area in mainland Tanzania. The country’s demand of forest products is strongly increasing due to substantial economic and population growth and increased urbanization. Currently the population growth is 2.7% p.a., the economic growth is 6.9% p.a. while the urban population growth is about 5% p.a. Such growth rates imply increasing pressure on forest lands and forestry. Charcoal and firewood are key products from the forest in Tanzania and are the country’s main fuels for cooking, with charcoal mainly used in urban areas. Production and consumption of charcoal and firewood play a significant role in enhancing the livelihoods of people, but may also lead to adverse environmental impacts. In Tanzania, large uncertainties exist about the present quantities of fuelwood consumed, as well as about the future integrated development of fuelwood demand and supply. The main objectives of this study are to improve the knowledge base regarding the present and future production and consumption of charcoal and firewood in Tanzania and their impacts on forest sustainability. More specifically, the thesis addresses the following research questions: Qi. What is the extent of land degradation and land rehabilitation potential in Tanzania? Qz. Which information do previous studies provide about charcoal and firewood production and consumption in Tanzania? Q3. What are the effects of price, income and household size on charcoal consumption in the three Tanzanian urban areas Dodoma, Morogoro and Mtwara? Q4. T o what extent is it possible to: (i) develop a dynamic forest sector partial equilibrium model for mainland Tanzania which consistently links forestry data regarding tree species, forest growth and growing stock from about 32,000 single plots in Tanzania's national forest inventory NAFORMA, with socio-economic data regarding the country’s present and future consumption and production of charcoal and firewood; and (ii) apply this model for analyzing how assumptions regarding population growth, urbanization rate and economic growth would influence the future consumption and production of firewood, charcoal and poles, forest resource use, and forest sustainability? In this thesis those questions are addressed in four papers, one for each question. Most efforts have been made in developing the quantitative model described in Q4, and issues related to theories of land-use or policy analyses are only briefly discussed. Below follows a summary of the papers and chapters 4 and 5 of the synopsis. Paper 1 aims at (i) assessing the potential for land rehabilitation in various regions of Tanzania based on new data from NAFORMA, and (ii) reviewing main experiences and economic results gained in previous land rehabilitation studies in the country. It is found that about 49% (43.3 mill ha) of the total land area in mainland Tanzania is under either light (43%, 37.7 mill ha), moderate (5%, 4.4. mill ha) or heavy (1.3%, 1.2 mill ha) erosion. These figures are substantial and imply large opportunities for land rehabilitation. The present land degradation is high, and parts of the degraded areas could be reforested, thus giving increased sustainable supply of forest and food products and maintaining environmental benefits, including increased carbon sequestration for global climate change mitigation. Very few economic studies are found on the benefits and costs of land rehabilitation in Tanzania, and new studies are highly needed in order to identify and prioritize among the potential rehabilitation activities. In Paper II, a review is presented of studies of charcoal production and consumption in Tanzania, and promising new research tasks are identified. Many interesting and valuable studies have been done, and it is clearly seen how important charcoal consumption and production are both in a social, ecological and economic perspectives. However, the results of the studies diverge a lot and most of the reviewed studies lack clear hypotheses and specifications of behavior theories to be used for developing realistic and testable hypotheses. It is found that more research is needed on factors effecting charcoal demand - like changes in prices, income and policies, and for that, using national household surveys is recommended. More research is also needed about tree regeneration (time and volumes) in miombo woodlands; how various forms of land ownerships influence miombo woodlands management; the possibilities and preferability in Tanzania of establishing forest plantations for producing charcoal; total and distributional impacts of policies related to production or consumption of fuelwood; climate gas emission impacts of charcoal production and consumption; development of bio-economic models which make possible consistent analyses of ex ante defined possible changes from the present socio-economic and policy situation. In Paper III, results are presented from a survey of 360 households in the three Tanzanian cities Dodoma, Morogoro and Mtwara about the impacts of income, charcoal prices and household size on the household per capita charcoal consumption. For the total sample, statistically significant elasticities for charcoal per capita consumption were found to be 0.03, -0.13 and -0.62 for respectively per capita income, charcoal price and household size. In the low income group, statistically significant elasticities for annual charcoal per capita demand were found to be - 0.44 and -0.59 for respectively charcoal price and household size; in the middle income group only household size was found to be statistically significant with estimated elasticity -0.81; and in the high income group elasticities of 0.17 for per capita income and -0.44 for household size were found statistically significant. These results are based on small samples and should be viewed as exploratory results of value primarily as information for larger surveys. Paper IV has as primary objectives to develop a forest sector model which integrates wood supply from detailed forest data from Tanzania’s NFI (National Forest Inventory) NAFORMA with demand for wood products, and apply this model to evaluate sustainability impacts of the future production and consumption of firewood, charcoal and poles in mainland Tanzania. The developed model (TanzFor) is classified as an intertemporally optimized spatial equilibrium model, and links in an economic consistent framework supply and demand for fuelwood, poles and charcoal as well as forest industry products. The study is the first one applying this kind of model in Africa with data from a detailed NFI as NAFORMA and newly developed forest growth functions as basis for the wood supply. The model results show alarming negative impacts on forest growing stocks by the steadily increasing consumption of firewood and charcoal in Tanzania, mainly caused by high population growth, high urbanization rates, low utilization efficiencies in both charcoal production and consumption, and rather free access to forest land. Chapter 4 of the synopsis gives a more overall, perspectively oriented discussion of the results obtained in Papers I-IV, focusing on uncertainty, linkages between the four thesis papers, connections to land use theories, relevance of forest sector modeling in Tanzania, policy implications and future research. The following topics are mentioned as being among the most interesting ones for future research: Further use of the NAFORMA data in fuelwood analyses; provide more accurate data on the present and future consumption of charcoal and firewood; analyze wood supply impacts of various kinds of property right regimes and policy means; improving forest sector modelling in Tanzania both regarding data input quality and incorporation of land property/ownership specifications; applying the model in estimating GHG emission and impacts of climate change in the forest sector; using the model in estimating impacts of policy means. It is emphasized, however, that like all models TanzFor has weaknesses and is a simplification of real life conditions, and that all TanzFor model results should be interpreted with that in mind. In Chapter 5 it is concluded that the above mentioned four research questions Q1-Q4 have been addressed and new results obtained which clearly show that the current consumption of wood in Tanzania is not sustainable. Tanzania is experiencing high and increasing production and consumption of charcoal particularly in urban areas where charcoal is the main type of energy for cooking. The results in this thesis indicate that challenges of fuelwood production and consumption will remain large in Tanzania for quite some time if no measures are taken to make cooking energy substitutes to charcoal more reliable and affordable than at present, and the charcoal production more efficient.Item Bioactivity potential of extracts from synadenium glaucescens pax (Euphorbiaceae)(Sokoine University of Agriculture, 2013) Mabiki, Faith PhilemonThe bioactivity of Synadenium glaucescens (Pax) extracts was studied in order to advance the knowledge that would enhance the utilization and commercialization of the plant. Participatory and questionnaire survey methods were used to establish ethnobotanical uses of the plant. Extracts from leaves, roots and stem samples were obtained using cold and hot extraction techniques. Brine shrimp test was involved for cytotoxicity studies. Using an in ovo method, extracts were tested against three viruses of veterinary importance. The agar well diffusion method and minimum inhibitory concentration were used to determine antibacterial and antifungal activity. Soxhlet extraction technique was used for optimization studies and GC-MS and HPLC for phytochemical screening. A total of 220 respondents were interviewed and majorities (94%) were aware of ethnomedical value of S. glaucescens. Twenty six uses were documented. Leaves and roots were the parts mostly used for ethnomedical purposes and grandparents were responsible for knowledge transfer. The cytoxicity test indicated LC50 values less than 30pg/ml for all extracts. More than 50% of the extracts prevented deaths, deformation and formation of pox lesions in embryos challenged with Infectious bursal disease virus and Fowl Pox virus at 0.2 mg/ml, without affecting the host cells. The extracts inhibited multiplication of Newcastle Disease virus at lowest concentration of 0.1 mg/ml. Treatment with ethanolic extracts from the root bark resulted into higher antiviral activity against the three viral particles. Extracts from hot extraction showed higher antibacterial and antifungal activity compared to the extracts from cold extraction. Gram positive bacteria were more sensitive to extracts than the Gram negative bacteria. Streptococcus pyogenes and Candida albicans were the most sensitive bacteria and fungus respectively. Ethanol extracts demonstrated higher antibacterial and antifungal activity than other solvent extracts. Higher extraction yields were obtained within 4 hours of extraction at 30°C for dichloromethane and 75°C for ethanol and particles size of 1 mm. Dichloromethane and ethanolic extracts were composed of triterpenoids and polyphenolic compounds respectively. These findings demonstrate the potential and the feasibility of using 5. glaucescens extracts for treatment of viral, bacterial and fungal diseases. Furthermore, it validates the ethnobotanical uses at community level.Item Indigenous knowledge system and factors limiting its integration into biodiversity conservation methods in South Nguru mountain forest reserve, Tanzania(Sokoine University of Agriculture, 2014) Ruheza, SosthenesThis study sought to explore the existing indigenous knowledge system (IKS) in four villages bordering the South Nguru Mountain Forest Reserve; to find out its significance in the conservation of biodiversity and to examine factors that influenced the system's integration into biodiversity conservation methods in the area. Using the exploratory cross-sectional research approach, and guided by the political ecology theoiy, this study triangulated interviews, focus group discussions (FGDs) and field observation to collect data from 240 randomly selected indigenous people; 60 from each study village. The Statistical Package for Social Sciences (SPSS) and content analysis were used to analyse quantitative and qualitative data respectively. This study revealed that IKS was embedded in the indigenous social structure and local politics, cultural norms, values and spiritual beliefs, with selective conservation. Social, demographic and economic factors were also seen to overtly influence integration of IKS into conservation methods, so was the lack of official recognition and capacity building of the indigenous social structures. In conclusion, despite Tanzania being a signatory of the 1992 Rio De Jeneiro Convention on Biological Diversity (CBD) and the Tanzania Forest Act of 2002 on active participation of indigenous people in biodiversity conservation, IKS and biodiversity conservation methods operate in a parallel and win-lose, rather than a win-win relationship. Recommendations put forth focus on official recognition of the IKS and active participation of the actors; motivation and capacity building; training on the significance of the IKS and addressing the problem of household-level poverty, while considering the demographic and socio-economic contexts of the local population.Item Dietary strategies to improve feeding practices dietary adequacy and growth of infants and young children in rural Tanzania(UNIVERSITEIT GENT, 2016) Kulwa, Kissa Buponelo MartinUndernutrition continues to affect many children below the age of five years in low- and middle income countries. Stunting, also commonly referred as linear growth faltering or retardation, is the most prevalent manifestation of undernutrition compared to wasting and underweight. A global reduction in the prevalence of undernutrition has been reported albeit regional variations. The number of stunted children is increasing steadily in sub-Saharan Africa. The 2010 Tanzania Demographic Health Survey showed unacceptably high levels of stunting, wasting and underweight among children below the age of five years; 42.0%, 4.8% and 15.8%, respectively. Children below the age of three years, children in rural areas and those living in the southern and central regions of the country were the most affected. Consequences of undernutrition during the formative years include poor growth, increased risk of and prolonged morbidity, mortality, delayed cognitive and motor development. Promotion of optimal feeding, health and growth during the first two years of life is a matter of immediate concern. Interventions to improve feeding and nutrition of infants during this period include promotion of breastfeeding, communication and education on complementary feeding behaviours, provision of food supplements, single and multiple micronutrients supplementation, reduction of diseases through appropriate hygiene practices, management and treatment of severe acute malnutrition. Reviews of previous interventions have reported that interventions with an educational component can effectively improve complementary feeding behaviours, dietary intake and child growth. There is limited information on the implementation and evaluation of evidence- and theory-based, culturally appropriate nutrition education interventions to improve diets and growth of rural infants in Tanzania. The aim of this thesis was to: 1) characterise dietary and growth patterns of infants and young children living in rural Tanzania, and 2) develop and evaluate the effectiveness of a nutrition education package on feeding practices, dietary adequacy and growth of infants and young children in rural Tanzania. It was hypothesised that the nutrition education package would improve feeding practices, dietary adequacy and growth as compared to the routine health education given at health facilities. To accomplish these objectives, the research was organised into two studies: two cross-sectional studies to establish the nutrition- and health-related problems in a rural area and guide decisions on improvement, and an intervention study to improve dietary practices and growth. A cross-sectional survey involving 496 infants (age 1-12 months) was conducted in six villages of Mpwapwa district in 2009 (Chapter 2). The study assessed feeding practices and nutritional status of children, and determined the macronutrient and selected micronutrient contents in commonly consumed complementary meals. Implications for dietary adequacy and nutritional status of the studied children are reported. The same cohort of infants (n=374, age 9-20 months) was revisited in 2010 to evaluate progress in their nutritional status after the first survey. Results of the 2009 survey showed that mean age of introduction of complementary foods (3.30±1.45) was earlier than the recommended age of six months. Porridge was the main complementary meal and the porridge samples contained relatively high water content, increasing the likelihood of reduced nutrient content. Mean number of meals consumed including snacks were lower than the age specific World Health Organization recommendations. There was limited inclusion of nutrient dense foods (e.g. legumes, animal-source foods, vegetables) in the meals. Small meal portion sizes, limited variety and the generally low nutrient content of meals increased the risk of not meeting the recommended nutrients intakes. Prevalence of stunting in 2009 and 2010 was 33.5% and 59.3%, respectively. Morbidity due to acute respiratory illness (ARI) was 63.9% in 2009 and 56.4% in 2010. Diarrhoea affected 48.4% children in 2009 and 36.4% in 2010 Overall prevalence of anaemia was 36.1% in 2009 and 36.7% in 2010. Results of the cross-sectional surveys demonstrated a need for a nutrition intervention to improve dietary practices, health and growth in infants and young children in rural Tanzania. While interventions to improve feeding, health and growth exist, it is imperative that they are contextualised to enhance feasibility and sustainability. Intervention Mapping and Theory of Planned Behaviour provided systematic frameworks for the design, development and evaluation of a nutrition education package (Chapter 3). The package had three components: 1) education, counselling and cooking demonstration with mothers, 2) training of village health workers (VHW) to counsel mothers and family members during monthly home visits, and 3) supervision of the trained village health workers. Training and education materials were also developed for respective participants. A cluster randomised controlled trial was implemented for six months in Mpwapwa district to evaluate the effectiveness of the package. Eighteen villages were randomly allocated to either routine health education (control, n=9) or nutrition education package (intervention, n=9). Routine health education is a standard government health service for children below the age of five years, offered monthly by health staff at health facilities. It offers education to mothers during growth monitoring and immunisation contacts. The sessions are usually short (10-15 minutes) and focus on general health issues including child feeding, prevention of diseases such as malaria and importance of immunisations. Primary outcome was length-for-age Z-scores. Secondary outcomes included weight, weight-for length Z-scores, intakes of energy, fat, iron and zinc from complementary foods, meal frequency and dietary diversity. A process evaluation was also carried out to provide insights into the nature of the processes leading to intervention effectiveness or ineffectiveness. A total of 370 infants aged 6-7 months (control: n=186; intervention: n=184) participated in the intervention trial starting December 2014. Findings of the trial are presented in Chapter 4. At baseline, inadequate feeding practices and nutrient intake, morbidity, anaemia and poor growth were widespread. After intervention, mean change in feeding frequency was modestly higher in the intervention than control group (1.63 vs. 1.27, p=0.051). Mean change in dietary diversity was significantly higher in intervention than control group (2.03 vs. 1 50, p=0.005). Infants in the intervention group had higher intakes of energy (+43.8 kcal, p=0.019) and fat (+2.7g, p=0.033) than infants in the control group. No effect was observed for iron and zinc intakes. The intervention resulted in significant mean change in length (0 47cm, 95% Cl: 0.01, 0.92, p=0.043) and length-for-age Z-scores (0.20 Z-score, 95% Cl: 0.29, 0.38, p=O.O22) in intervention compared with the control group. The intervention had no differential effects on mean changes in weight, weight-for-length and weight-for age Z-scores. Chapter 5 presents results of the process evaluation. Fidelity, recruitment, reach, dose and contextual factors were reported for each package component. The package components and elements (training VHW, education and cooking demonstration with mothers, home visits, supervision of VHW) were implemented across the intervention villages as planned. The intervention was well received with good dose and was well accepted by VHW, mothers and their families. VHW knowledge on IYCF increased significantly during the two training sessions (I'1 session: +5.7-point, p<0.001; 2nd session: +4.1-point, p=0.003). Between midtrial and end of trial, the majority of mothers tried the promoted recipes at home (89.8% and 94.6%) and some tried all the recommended feeding and health practices (37.7% and 66.1%) Barriers to adoption of the recommended practices included high maternal workload, cultural beliefs on feeding choices and inadequate household income. Chapter 6 discusses the implications of the findings and recommendations for further research. In conclusion, this PhD research demonstrated that inadequate dietary practices and poor nutrition are consistently widespread in infants and young children in rural settings. Further, the nutrition education package adds to the evidence that practical nutrition education incorporating cooking demonstrations and regular home visits can improve feeding practices, dietary intake of macronutrients and growth, better than the routine health education delivered at health facilities. Child health status, socio-cultural and household factors played a significance role in influencing intervention outcomes. Barriers to intervention effects included high infant morbidity, high maternal workload, inadequate household income and mothers' habitual and cultural influences on feeding choices. The research calls for a review of routine health education for the delivery of quality nutrition services and improvement of child health services for reducing morbidity burden. There is also a need for joint strategies with other sectors (e.g. agriculture-livestock production, marketing-roads infrastructure, income generation initiatives) to address the underlying causes of child undernutrition.Item Molecular cloning and functional characterization of tenebrio PGRP-LE, PGRP- LB and autophagy-related genes ATG3, 5 and 8 in response to listeria monocytogenes and pseudomonas geniculata HT1 infection(Chonnam National University, 2015) Tindwa, Hamisi JumaThe Current study investigated innate immune responses of the mealworm beetle, Tenebrio molitor, against microbial infections. We, therefore, dealt with two major themes, the immune functions of autophagy-reiated genes TmATG3, TmATG5 and TmATG8 on the one hand and, roles of TmPGRP-LE and TmPGRP-LB in immune responses to microbial infections on the other hand. In the first pail, the three autophagy-related genes, TmATG3, TmATG5^ and TmATG8 were identified and characterized for their immunological functions in the beetle against infections by an intracellular pathogen, Listeria monocytogenes. TmATG39 TmATG5 genes were identified from T. molitor EST and RNAseq databases. The cDNA of TmATG3 and TmATG5 comprise of ORF sizes of 963 and 792 bp encoding proteins with 320 and 263 amino acid residues, respectively. TmATG3 and TmATG5 transcripts are detected in all developmental stages analyzed, and primarily in fat body and hemocytes of larvae. TmATG3 and TmATG showed high amino acid sequence identity (58-95%) with corresponding homologues from various insects and were closer to their orthologs in T. castaneum. Loss of function of TmATG3 and TmATG5 by RNAi led to a significant reduction in survival ability of T. molitor larvae against an intracellular pathogen, L. monocytogenes. Six days post-Listeria challenge, the survivability in dsTwJTGJ- and dsTmATG5-treated larvae was significantly reduced to 3 and 4%, respectively, when compared with dsEGFP-injected control larvae. The cDNA cfiTmATG8 comprises of an ORF of 363 bp encoding a protein of 120 amino acid residues. TmATG8 transcripts are detected in all the developmental stages analyzed. TmAtg8 contains a highly conserved C-terminal glycine residue (G116) and shows high amino acid sequence identity (98%) to its T. castaneum homologue, TcAtg8. Loss of function of TmATG8 by RNAi led to a significant increase in mortality of T. molitor larvae against Listeria monocytogenes. Unlike dsEGFP-treated control larvae, Tw/lTUS-silenced larvae failed to turn-on autophagy in hemocytes after L. monocytogenes injection. Taken together, these data suggest that TmATG3, TmATG5 and TmATG8 play a role in mediating autophagy-based clearance of Listeria in T. molitor. In the second part, TmPGRP-LE and TmPGRP-LB were identified and characterised for their immunological functions in T. molitor. A PGRP-LE homologue, from T. molitor was identified and characterized for its functional role in the survival of the insect against infection by a DAP-type PGN containing intracellular pathogen, L. monocytogenes. TmPGRP-LE cDNA is comprised of an open reading frame (ORF) of 990 bp and encodes a protein of 329 residues. TmPGRP-LE contains one PGRP domain, but lacks critical residues for amidase activity. Quantitative RT-PCR analysis indicated a broad constitutive expression of the TmPGRP-LE transcripts at various stages of development spanning from larva to adult. RNAi-mediated knockdown of the TmPGRP-LE transcript, followed by a challenge with L. monocytogenes, resulted in a significant reduction in survival rate of the larvae, suggesting a putative role of TmPGRP-LE in sensing and control ofL. monocytogenes infection in T. molitor. PGRP-LB, one of several amidase-capable members of the PGRP family has been demonstrated to specifically recognize DAP-type PGN, thereby preventing over-activation of the IMD pathway upon infections Gram-negative bacteria. We have identified, cloned and partially characterized the immunological functions of a PGRP-LB homologue from T. molitor against a newly isolated Gram-negative bacterium Pseudomonas geniculata HT1 infection. TmPGRP-LB has an ORF of 597 bp encoding a protein with 198 amino acid residues and contains the conserved PGRP domain. TmPGRP-LB is closest to its orthologous TcPGRP-LBl and TcPGRP-LB2 isoforms in T. castaneum with which it shares the highest (73 %) percentage identity. TmPGRP-LB transcripts were detected in all developmental stages examined spanning from the late-instar larva to adult day 1 and 2. TmPGRP-LB transcripts were also detected in all tissues examined including the gut, hemocytes, fat body, Malphigian tubules, integuments, ovaries and testes. Infection of Tenebrio larvae with HT1 resulted in increased expression of TmPGRP-LB but not other IMD pathway-related genes TmPGRP-LC and TmPGRP-LE. TmPGRP-LB loss of function by RNAi resulted in increased susceptibility of larvae to infections by Gram-negative bacteria HT1 and Escherichia coli KI2 but not Gram-positive bacteria Staphylococcus aureus RN4220. Our results suggest that TmPGRP-LB plays a role in control of Gram-negative infections in T. molitor. Overall, we have demonstrated that both autophagy and peptidoglycan recognition proteins of the IMD pathway are deployed to counter bacterial infections in T. molitor