Browsing Okavango Research Institute (ORI) by Title
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Mbaiwa, J.E.; Stronza, A.M. (Routledge (Taylor & Francis) www.routledge.com, January 19, 2010)[more][less]
Abstract: The Community-Based Natural Resource Management (CBNRM) program in Botswana aims to achieve biodiversity conservation and rural development in rich biodiversity areas like the Okavango Delta. CBNRM assumes that if rural communities derive benefits from natural resources, they will be obliged to use such resources sustainably. Using the sustainable livelihoods framework, this study analyzes the effects of tourism development through CBNRM on rural livelihoods at Khwai, Sankoyo and Mababe in the Okavango Delta, Botswana, using primary and secondary data sources. Results of long-term surveys and in-depth interviews indicate that the three communities have forgone traditional livelihood activities such as hunting and gathering, livestock and crop farming to participate in tourism through CBNRM. Livelihoods in these villages have been improved as a result. Basic needs such as shelter, employment and income and social services like water supply systems, transportation, scholarships and payment of funeral expenses are now provided to community members and funded with income from CBNRM. Social capital has been built up in order to agree, manage and develop the CBNRM process. These results show that tourism development in these villages is achieving its goal of improved livelihoods, contradicting claims that community development projects are failing to achieve rural development. URI: http://hdl.handle.net/10311/960 Files in this item: 1
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Mbaiwa, J.E.; Mbaiwa, O.I. (International Journal of Wilderness; http://ijw.wilderness.net/, December NaN, 2006)[more][less]
Abstract: This article examines the effects of veterinary fences on wildlife populations in the Okavango Delta, Botswana. Using data from secondary data sources, findings indicate that the existence of veterinary fences in the Okavango Delta contributes to the decline of wildlife species in Botswana. Veterinary fences are erected to control the spread of livestock diseases in order to protect the European Union beef market where Botswanaâ s beef is largely exported. Migratory wildlife species such as wildebeests, zebras, giraffes, buffalo, and tsessebes have their migratory routes blocked by veterinary fences and hence die from dehydration and entanglements in the fence. Those that get trapped by the fence often become easy kill targets for poachers. Some of the animals have been observed walking along the fence trying to cross. The erection of veterinary fences indicates that the expansion of livestock production into wildlife areas threaten the survival of wildlife in Botswana. To address the problem, an integration of wildlife production with other sectors such as agricultural development should be made a priority at national and local policy levels. This means that the principles of sustainability should be given priority in the erection of veterinary fences in wildlife areas. URI: http://hdl.handle.net/10311/28 Files in this item: 2
license.txt (1.998Kb)mbaiwa_int_j_wilderness_2006.pdf (338.1Kb) -
Mmopelwa, G.; Mosepele, K.; Mosepele, B.; Moleele, N.; Ngwenya, B. (Blackwell Publishing, http://www.blackwellpublishing.com, NaN, 2009)[more][less]
Abstract: The hydrological regime of the Okavango River Basin is the main driver of ecological change in the delta. The delta supports a small-scale fishery which is a source of livelihood for communities within its fringes. The fish resource is particularly important to subsistence fishers, who have limited access to socio-economic opportunities. However, fish availability is subject to ‘concentration and dilution’ effects because of the hydrological regime. As a copying strategy, fishers use a variety of fishing methods to effectively harvest the delta’s fish community across all its trophic levels. This exploitation regime helps to maintain the delta’s species diversity and only reduces fish biomass proportionally across the different trophical levels. Furthermore, fishers have developed different fish-processing techniques to preserve their harvest for low fishing season periods to cope with low food availability. The aim of this paper therefore, was to explore spatio-temporal variations in fish availability and to show how the delta’s subsistence fishers cope with this dynamicity. URI: http://hdl.handle.net/10311/862 Files in this item: 1
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Heinl, M.; Frost, P.; Vanderpost, C.; Sliva, J. (Elsevier; http://www.elsevier.com/wps/find/journaldescription.cws_home/622855/description#description, May 8, 2006)[more][less]
Abstract: Satellite imagery derived fire history data for the southern Okavango Delta, Botswana from 1989 to 2003 were used to analyse the temporal and spatial distribution of fires and to assess changes in fire activity. Maximum fire activity was encountered for 1997 with 24.1% of the study area burned. The annual extent of the burned area fluctuated considerably, but there appeared to be a regular oscillation apparently induced by floodplain fires. The main fire activity on drylands is in September at the end of the dry season, while most floodplains burn earlier in the year. Both burning of floodplains and drylands appear to peak prior to floods and rainfall-events, respectively. Areas with highest fire frequency were outlined and spatial analyses showed that fires on the drylands are largely due to burning of adjacent floodplains. The floodplains were therefore identified as the centres of fire activity, being the regions with the highest fire frequency and serving as source of fires spreading into drylands. Floodplains showed higher fire frequencies compared to drylands, but no increase in fire activity was detected over the study period for both floodplains and drylands. Description: The study was part of the project 'Fire regime and vegetation response in the Okavango Delta, Botswana' funded by the Volkswagen Foundation, Germany and carried out by the Chair of Vegetation Ecology, Technische Universitaet Muenchen, Germany in collaboration with the Harry Oppenheimer Okavango Research Center (HOORC, University of Botswana) and University of Pretoria, South Africa. Financial support was also given by Conservation International Botswana and the German Academic Exchange Service (DAAD). URI: http://hdl.handle.net/10311/151 Files in this item: 2
heinl_j_arid_env.pdf (392.9Kb)license.txt (1.998Kb) -
Mubyana-John, T.; Wutor, V.C.; Yeboah, S.O.; Ringrose, S. (Academic Journals. http://www.academicjournals.org/SRE, NaN, 2007)[more][less]
Abstract: The influence of wild fires on microbial community structure, soil organic matter, sulphur oxidising and nitrifying microbial populations in the floodplains of the Okavango Delta of Botswana was assessed. Microbial community structure was assessed by phospholipids ester-linked fatty acids (PLFA) quantification while microbial sulphur oxidisers were assessed by Most Probable Number (MPN). Community structure assessment showed that burning shifted the microbial community structure from single cellular bacteria being the dominant groups to filamentous fungi and actinomycetes being the most dominant groups. Generally burning increased the fungal component (18:2 w6) matrix from 3.40 to 8.35 while the actinomycetes and sulphur reducing bacterial (10 Me 16:0) component also increased from 1.02 to 1.70 mostly in the floodplains. Generally, the organic matter content declined with burning. However, the influence of burning on soil pH was non conclusive. Soil microbial biomass carbon increased slightly after the fire. The number of heterotrophic and nitrite-oxidizing and sulphur reducing bacteria increased. Overall, these results indicate that burning significantly alters the microbial community structure as large above ground losses of nutrients during and after burning often results in low quantities of nutrients released into the soil. URI: http://hdl.handle.net/10311/349 Files in this item: 1
Fire and.pdf (2.461Mb) -
Omari, K.; Mubyana, T.; Matsheka, M.I.; Bonyongo, M.C.; Veenendaal, E. (South African Journal of Botany http://www.elsevier.com/wps/find/journaldescription.cws_home/707238/description#description, NaN, 2004)[more][less]
Abstract: Effects of flooding on soil nitrogen (N), and asymbiotic nitrogen fixing bacterial (diazotroph) populations of the Okavango Delta were investigated. Diazotrophs from the rhizosphere of dominant annual and perennial grasses of the Okavango Delta were isolated on N-free composite media and identified applying morphological and biochemical criteria and Restriction Fragment Length Polymorphism (RFLP). Azotobacter species were found associated mostly with the grasses Andropogon guyanus and Vetevaria nigritiana (103CFU g–1 rhizosphere soil). Annual grasses such as Eragrostis inamoena, Setaria sphacelata as well as perennials showed insignificant populations (<101CFU g–1 soil). On the contrary, Azospirillum spp. was found associated with most of the grasses. Highest population densities (above 104MPN g–1 soil) were observed in rhizospheres of E. inamoena, Cympogon excavatus, Sporobolus acinifolis, Eragrostis lapila and Eragrostis rigidor and lowest population densities (below 102MPN g–1 soil) in rhizospheres of Andropogon guyanus and Panicum repens. Flooding increased the Azotobacter populations, while Azospirillum spp. populations were significantly reduced. Nitrogen-fixing sulphur reducers were observed in the rhizosphere of annuals (A. guyanus and P. repens) and only in perennials growing in flooded soils. No Beijerinckia species were found associated with any of the grasses. The highest soil nitrogen levels were detected in flooded soils (<0.20% N) while no N was detected in the rhizosphere soil of grasses growing in very dry soils (<5% moisture content). The results indicate that in the Okavango Delta, total soil nitrogen varies with flooding regime. With flooding, the diazotroph population shifts towards Azotobacter and Nfixing sulphur reducers while Azospirillum spp. are widespread in non-flooded soils. RFLP analysis of the 1 450bp amplicon using the restriction endonuclease Alu1, showed three different banding profiles, suggesting the occurrence of three different species of Azospirillum. URI: http://hdl.handle.net/10311/294 Files in this item: 1
Flooding and its influence.pdf (2.253Mb) -
Gumbricht, T.; Wolski, P.; Frost, P.; McCarthy, T.S. (Elservier, www.elsevier.com, NaN, 2004)[more][less]
Abstract: The pristine Okavango Delta wetland of northern Botswana is potentially under threat due to water abstraction from its tributaries. We have developed a statistical model which makes it possible to predict the extent of wetland loss which will arise from water abstraction. The model also permits prediction of the maximum area of flooding, and its spatial distribution, three months in advance of the flood maximum. The model was calibrated using maximum areas of seasonal inundation extracted from satellite imagery covering the period 1985-2000, which were correlated with rainfall and total flood discharge. A technique was developed to translate the modelled flood area into a flood map. The methodology can predict maximum area of flooding and its distribution with better than 90% accuracy. An important, although relatively minor, source of error in the spatial distribution of the flood arises from a secular change in flood distribution in the distal Delta which has taken place over the last 15 years. Reconstruction of flooding history back to 1934 suggests that the Delta may be subject to a quasi 80 year climatic oscillation. If this oscillation continues, the extent of flooding will increase in the coining decades. URI: http://hdl.handle.net/10311/948 Files in this item: 1
Gumbricht JOH 2004.pdf (2.449Mb) -
Southworth, J.; Nagendra, H.; Cassidy, L. (Taylor & Francis, June 3, 2011)[more][less]
Abstract: Tropical forest habitat continues to decline globally, with serious consequences for environmental sustainability. The South/Southeast Asian landscapes represent one of the most challenging parts of the world to study issues of landscape change. High population densities in the region pose major threats to forest cover. Despite presentations of supposedly catastrophic declines in forest cover, substantial areas have been observed to maintain or increase forest cover in recent years. This research draws on data from Nepal, India, Thailand, and Cambodia to examine trajectories of forest-cover change along gradients of deforestation and reforestation. The gradients we observe extend from Cambodia, a still predominantly forested landscape, with development and change at initial stages, to Nepal which, despite having experienced large-scale forest clearing in the past, has considerable reforestation in recent years. Understanding these processes is critical for policymakers working on climate change and adaptation. This research allows us to link national-scale and local-scale analyses, in terms of both their similarities and differences, and also to see changes still in progress via the inclusion of regrowth and degradation classes, not just reforestation and deforestation. URI: http://hdl.handle.net/10311/826 Files in this item: 1
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Fynn, R.W.S.; Bonyongo, M.C. (Wiley, November NaN, 2010)[more][less]
Abstract: Ungulate populations in African conservation areas (CAs) are in widespread decline, which can largely be attributed to a lack of functionality of the area encompassed by the CAs themselves. We present evidence from a wide range of African CAs showing that they do not encompass both the functional wet- and dry-season resources that ungulates traditionally migrated between. Before human populations and economic development had grown to levels where they interfered with migrations outside the CAs, ungulates were able to make use of their traditional seasonal resources but this is becoming increasingly difficult and we are now seeing the effects of this restriction of movement on ungulate population numbers. New innovative strategies are required for the conservation of African wildlife. An urgent Africa-wide survey is needed to establish past and present functional resources in and around CAs and to prioritize conservation regions that are most functional. In addition, innovative attempts need to be made to reconsolidate functional seasonal resources within revised expanded protected areas. URI: http://hdl.handle.net/10311/781 Files in this item: 1
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Bartsch, A.; Wagner, W.; Scipal, K.; Sabel, D.; Wolski, P. (Elsevier, March 17, 2008)[more][less]
Abstract: This paper elaborates on recent advances in the use of ScanSAR technologies for wetland-related research. Applications of active satellite radar systems include the monitoring of inundation dynamics as well as time series analyses of surface soil wetness. For management purposes many wetlands, especially those in dry regions, need to be monitored for short and long-term changes. Another application of these technologies is monitoring the impact of climate change in permafrost transition zones where peatlands form one of the major land cover types. Therefore, examples from boreal and subtropical environments are presented using the analysed ENVISAT ASAR Global mode (GM, 1 km resolution) data acquired in 2005 and 2006. In the case of the ENVISAT ASAR instrument, data availability of the rather coarse Global Mode depends on request priorities of other competing modes, but acquisition frequency may still be on average fortnightly to monthly depending on latitude. Peatland types covering varying permafrost regimes of the West Siberian Lowlands can be distinguished from each other and other land cover by multitemporal analyses. Up to 75% of oligotrophic bogs can be identified in the seasonal permafrost zone in both years. The high seasonal and interannual dynamics of the subtropic Okavango Delta can also be captured by GM time series. Response to increased precipitation in 2006 differsfrom flood propagation patterns. In addition, relative soil moisture maps may provide a valuable data source in order to account for external hydrological factors of such complex wetland ecosystems. URI: http://hdl.handle.net/10311/767 Files in this item: 1
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Bonyongo, M.C.; Harris, S. (Willey Blackwell Publishing http://eu.wiley.com/WileyCDA/Brand/id-35.html, NaN, 2007)[more][less]
Abstract: We used body weight ratio to determine the degree of species-packing of the Okavango Delta (22,000 km2) grazers and compared it to that of four conservation areas of similar sizes but varying in the diversity of habitat types. They are Etosha National Park (23,175 km2) in Namibia, Hwange National Park (14,621 km2) in Zimbabwe, Kafue National Park (24,000 km2) in Zambia and Kruger National Park (19,633 km2) in South Africa. We considered possible ecological explanations for existing gaps within the assemblage. The weight ratio (measure of the degree of species-packing) of the grazers of the Okavango Delta was 1.25, with a total of 27 species which was far less than the theoretically expected 2.0. One-way analysis of covariance (ANCOVA) showed that there were significant differences in the degree of species-packing between the Okavango Delta and other conservation areas of similar size in southern Africa (F1,5 ¼ 166, P < 0.001). Regressing habitat heterogeneity (expressed as number of different habitat types) on species-packing of the five conservation areas yielded a positive linear relationship with R2 ¼ 0.76 implying that 76% of the variation in the degree of speciespacking in the five conservation areas is explained by variation in habitat heterogeneity. We conclude that size ratios are useful descriptors of animal communities and it is a useful measure of species diversity, which can be used for monitoring purposes. Imbalances in weight ratios provide a measure of identifying perturbations due to species loss or arrival of new species within a natural ecosystem. URI: http://hdl.handle.net/10311/608 Files in this item: 1
Bonyongo_AJE_2007.pdf (1.153Mb) -
Sajidu, S.M.I.; Masamba, W.R.L.; Thole, B.; Mwatseteza, J.F. (Academic Journals, http://www.academicjournals.org/ijps, NaN, 2008)[more][less]
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VanderPost, C.; McFarlane, M. (Elsevier www.elsevier.com/locate/jag, NaN, 2007)[more][less]
Abstract: Locating additional long-term groundwater resources in semi-arid regions of developing countries with growing populations is an expensive undertaking. Simple geographic information system (GIS) techniques can be utilised to facilitate efficient application of expensive geophysical techniques and test-drilling by functioning as an interdisciplinary integration and decision-making tool, especially in data-poor and poorly mapped environments where more sophisticated GIS techniques are not applicable. The paper demonstrates this in the context of the search for groundwater alternatives to the dwindling river water supply in the Boteti area of the Kalahari region in Botswana. URI: http://hdl.handle.net/10311/573 Files in this item: 1
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Bonyongo, C.M. (Botswana Society, NaN, 2005)[more][less]
Abstract: This paper presents preliminary results from a long-term study on the ecology of large herbivores in the Okavango Delta. The paper evaluates habitat selection and utilization by impala (Aepyceros melampus) at the various habitat scales. Impala, the most abundant and widely distributed mammal species in the Delta, showed seasonality in habitat use and habitat selection. In all seasons impala used mixed open woodlands more than any other habitat type. Open grasslands and upper floodplains are also key habitats for impala. As a mixed feeder, impala are able to use a wide range of habitats. URI: http://hdl.handle.net/10311/931 Files in this item: 1
Bonyongo 2005 Habitat.pdf (1.198Mb) -
Ngwenya, B.N.; Kgathi, D.L. (Elsevier Ltd; www.elsevier.com/locate/pce, NaN, 2006)[more][less]
Abstract: This case study investigates access to potable water in HIV/AIDS related home-based care households in five rural communities in Ngamiland, Botswana. Primary data collected from five villages, consisted of two parts. The first survey collected household data on demographic and rural livelihood features and impacts of HIV/AIDS. A total of 129 households were selected using a two-stage stratified random sampling method. In the second survey, a total of 39 family primary and community care givers of continuously ill, bed-ridden or non-bed-ridden HIV/AIDS patients were interviewed. A detailed questionnaire, with closed and open-ended questions, was used to collect household data. In addition to using the questionnaire, data was also collected through participant observation, informal interviews and secondary sources. The study revealed that there are several sources of water for communities in Ngamiland such as off-plot, outdoor (communal) and on-plot outdoor and/or indoor (private) water connections, as well as other sources such as bowsed water, well-points, boreholes and open perennial/ephemeral water from river channels and pans. There was a serious problem unreliable water supply caused by, among other things, the breakdown of diesel-powered water pumps, high frequency of HIV/AIDS related absenteeism, and the failure of timely delivery of diesel fuel. Some villages experienced chronic supply disruptions while others experienced seasonal or occasional water shortages. Strategies for coping with unreliability of water supply included economizing on water, reserve storage, buying water, and collection from river/dug wells or other alternative sources such as rain harvesting tanks in government institutions. The unreliability of water supply resulted in an increase in the use of water of poor quality and other practices of poor hygiene as well as a high opportunity cost of water collection. In such instances, bathing of patients was cut from twice daily to once or not at all. Depending on the severity of HIV/AIDS related symptoms, e.g. diarrhoea, 20-80 additional litres of water could be required daily. The case study demonstrates that, at individual level, access to water is an integral element of the patient's holistic healing process and psychosocial well being. At household and community levels, access to sufficient supplies of potable water when and where it is needed is central to mitigation of HIV/AIDS impacts. Access to water should therefore not be treated strictly as an economic good due to its importance as a basic human need, a social good and indeed a human right. URI: http://hdl.handle.net/10311/172 Files in this item: 2
license.txt (1.998Kb)ngwenya_kgathi_PCE_06.pdf (4.416Mb) -
Ngwenya, B.N.; Mosepele, K. (Elsevier www.elsevier.com/locate/pce, NaN, 2007)[more][less]
Abstract: Generally, rural households pursue all year round natural and non-natural resource-based livelihood systems to diversify these options in order to cope with risks emanating from a range of shocks and stressors. Artisanal fishing in the Delta is not only a major livelihood option but also a source of food security. This paper is based on analysis of primary data collected from a survey of 248 subsistence fishers’ households through simple random sampling in 22 villages in the Delta. The overall objectives of the survey were to assess the general prevalence of HIV/AIDS in the Ngamiland district of Botswana, to investigate potential effects of AIDS-related stressors, particularly chronic illness on artisanal fishing activities, and to assess implications towards food security. Results from this study indicate that HIV prevalence rates for pregnant women attending antenatal clinics in the Delta are approximately 30% and are related to factors such as marriage, education, and employment. Despite this relatively high prevalence percentage, most of the affected households do not have adequate access to HIV/AIDS support facilities. Support services are provided on the basis of population size and/or status of the settlement (i.e. urban, urban village, rural or remote). Therefore, since about 50% of the Delta’s population lives in settlements of less than 500 people, they receive health services indirectly through major population centres whose capacity to deliver timely HIV/AIDS services is limited. This disproportionate access to HIV/AIDS services disadvantages the majority of fishing communities in the Delta, and may affect their ability to fish. Moreover, about 53% of sampled households had cared for a continuously ill person/s (CIP’s) in the last 5 years, out of which approximately 29% felt that this seriously impacted fishing activities. These serious impacts included sale of family assets, depletion of savings, and switching or abandoning fishing activities. Subsequently, household food security is seriously affected because fish provides a significant proportion of food to CIP households where approximately 55% of households get their food from fish products. During food shortages, CIP households resorted to a hierarchy of strategies which included cutting down on meals or reducing meal portions, looking for paid work, gathering wild fruit, asking for food from relatives, selling livestock, and getting social assistance. In conclusion, artisanal fishing is a natural safety net which constitutes an important buffer for households affected by HIV/ AIDS-related stressors in the Okavango Delta. Access to fish helps these households mitigate potentially adverse impacts such as deterioration into chronic poverty. URI: http://hdl.handle.net/10311/572 Files in this item: 1
NGWENYA2007Okavango.pdf (1.602Mb) -
Phorano, O.M.; Nthomang, K.; Ngwenya, B.N. (Botswana Society, NaN, 2005)[more][less]
Abstract: Batswana have been hard-hit by the HIV/AIDS pandemic. The Botswana government has initiated the Community Home-Based Care programme to provide material support for HIV/AIDS patients cared for at home by family members and relatives. This paper identifies and explores emerging home care issues and pays specific attention to potential risks related to poorly managed clinical human and solid waste disposal generated through home-based care of HIV/AIDS patients in Ngamiland and Kweneng Districts in Botswana. Data were collected through focus group discussion with care-givers, discursive interviews with professional service providers, and participant observation. The results of the study indicate that the majority of care givers received material benefits provided through the CHBC programme. However, it was clear that CHBC did not have the capacity to address other critical needs for the proper care of patients in the home. Most households studied are very poor and lack basic facilities such as toilets, basic waste receptacles and regular collection of solid waste. Access to these facilities is important for disposing of both clinical and ordinary human and solid waste from HBC patients. Poor sanitation facilities - especially the improper handling of soiled laundry and inadequate ventilation - increase risks of infection. The study recommends the formation of care-giver support groups to reduce risks associated with poorly managed clinical solid waste disposal generated from home care-giving of HIV/AIDS patients. URI: http://hdl.handle.net/10311/952 Files in this item: 1
Phorano 2005 HIV.pdf (2.631Mb) -
Ngwenya, B.N.; Butale, B.M. (Botswana Society, NaN, 2005)[more][less]
Abstract: Home care involves the transfer of a patient’s medical supervision from a formal institution to a family setting in the context of a community. The aim of this paper is to assess the resource capacity of families to provide immediate home care to HIV/AIDS related chronically or terminally ill member/s in Maun in Ngamiland District. Data for the study was obtained through cross-sectional interviews with 61 care-givers. Ethnographic methods were also used: these included informal interviews with key informants, unobtrusive participant observation, and narratives of individual and family life experiences. Data collection focused on assessing family resource capacity to access three forms of capital, namely social, productive and produced. Issue focus analysis on qualitative data, and descriptive frequencies and cross-tabulations on quantitative data were carried out. Generally, care-givers reported receiving non-material support from multiple sources. These included moral support from close family members, especially their own children, siblings, parents and spouses, and less from parents’ in-law and their extended family. The threshold of care-giving resource demands could either fragment the family unit, on precipitate ‘enclave-like’ or ‘disengaged’ co-existence or passive aggression. On the other hand, caregiving resource demands may enhance mutual obligation and shared responsibility among family members. A high level of tolerability tends to reduce vulnerability and facilitate pooling limited resources in ways that enhance family capacity. Conversely, adversarial intra-family relations compromise the ability of a family to mobilize its resources. About 70% of care-givers were dependent on non-farming activities as their source of livelihood. Care-giving depletes family resources, including the abandonment of income generating activities. About 81% of care-givers said that they could not do anything to recover or reverse the loss. Access to produced capital such as telecommunication infrastructure is important in terms of the dissemination of public education information aimed at helping reduce risks and the prevention of infection. A significant proportion of care-givers had access to a radio (60%) and cell-phone (48%). The paper ends with some policy recommendations. URI: http://hdl.handle.net/10311/953 Files in this item: 1
Ngwenya 2005 AIDS.pdf (3.334Mb) -
Mmopelwa, G.; Kgathi, D.L.; Masamba, W.R.L.; Thukuza, A. (Botswana Society, NaN, 2005)[more][less]
Abstract: Water supply in Maun is unreliable and unpredictable, and most households experience water shortage all year round. Coping strategies for households include water storage in tanks. Water quality is also poor due to its salty taste, presence of sediments and colour. The majority of households have henceforth embarked on coping strategies such as buying bottled water. On average, households spend about P71 per month as avoidance cost. A contingent valuation method assessment was carried out and it was found that the mean maximum household’s willingness to pay for a water quality improvement fund was P55 per month. Chemical analysis carried out on water samples from the study area confirm that the water has high electrical conductivity, sediments, colour, and iron and manganese levels. URI: http://hdl.handle.net/10311/938 Files in this item: 1
Mmopelwa 2005 House.pdf (1.540Mb) -
Kurugundla, C.N.; Bonyongo, M.C.; Serumola, O. (Taylor & Francis, December 22, 2010)[more][less]
Abstract: The risk and effect of the insecticide deltamethrin, applied aerially in Botswana to control and eradicate tsetse fly, was studied on the non-target weevil Cyrtobagous salviniae, a biocontrol agent of the aquatic weed Salvinia molesta. Environmentally-simulated short-term toxicity bioassay used open iron cages and closed plastic basins containing weevils and salvinia placed in riverine water bodies, where they were exposed to the aerial applications of deltamethrin over the Kwando–Linyanti system in 2006. Control samples were placed 40 km outside the sprayed area. Weevil mortality, determined at 12, 36 and 60 hours after the aerial application, reached a maximum of 27%. No significant difference in mortalities was observed between the closed basins and the open cages. The amount of deltamethrin deposited at ground level was between 1.2 and 6.4 μg m–2 and the insecticide toxicity was related to the weevil mortality. Simultaneous field monitoring through five spray applications showed that weevil abundance declined in late winter. Deltamethrin had a negligible impact on the weevil’s ability to control salvinia under field conditions, probably due to the weevils’ protective mechanism and because vegetation could act as a barrier, preventing the insecticide from reaching the weevils. Minimum impacts of deltamethrin on the weevils in the present study and their recovery in the field are consistent with those of earlier spray applications in the Okavango Delta, Botswana. URI: http://hdl.handle.net/10311/808 Files in this item: 1