Browsing Environmental Science by Title
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Kizza, Sarah; Totolo, Otlogetswe; Perkins, Jeremy; Areola, Olusegun (Academic Journals, http://www.academicjournals.org, December 4, 2011)[more][less]
Abstract: The aim of this study was to analyze the depletion of soil nutrients with time on abandoned kraals in a peri-urban area of Botswana. Active kraals are enriched with nutrients through the accumulation of animal droppings and this study was aimed at assessing how long the impact of this soil nutrient enrichment persists after kraal abandonment. A total of 25 disused kraals, that had been abandoned for periods ranging from 1 to 45 years were sampled. The soil parameters analyzed included particle size distribution (%), bulk density (g/cm3), pore space (%), moisture content (%), pH in water and KCl solution, EC (μS/cm), organic matter (%), CEC (meq/100g), exchangeable Ca++(cmolc/kg), Mg++(cmolc/kg), K+(cmolc/kg), Na+ (cmolc/kg), nitrogen [NH4-N (mg/kg), NO3-N (mg/kg), TKN (%), and Olsen P (mg/kg). Results showed that soil nutrient concentrations on abandoned kraals generally were significantly higher than at the control sites. Soil nutrient concentrations decreased with time as abandoned kraals retrogressed towards their pre-kraal conditions. However, the effects of soil nutrient enrichment from animal wastes persist long after kraal abandonment. For example, soil Olsen P, Ca++ and Mg++ levels in kraal sites that had been abandoned for over 45 years were still significantly higher than in the control sites. In a pastoral system such as is practiced in Botswana where kraal manure is not used as soil amendment, the whole ecosystem suffers as soil nutrients are transferred and concentrated at isolated spots (kraals). Description: Full Length Research Paper URI: http://hdl.handle.net/10311/1016 Files in this item: 1
Kizza et al.pdf (696.1Kb) -
Kizza, S; Areola, O (Academic Journals, November NaN, 2010)[more][less]
Abstract: This study investigated the influence of the accumulation of animal wastes on the soils of active kraal sites through time. This investigation involved the sampling and analysis of the soils of kraals that had been in use for periods ranging from 2 to over 45 years. Soil sampling and analysis were done both in the dry and wet seasons for comparative purposes. The properties of the kraal soils were compared with those of control sites. Samples were taken from 25 kraals categorized into 5 age (length of use) groups: < 5years; 6 - 10; 11 - 20; 21 - 40; > 40 years. The soils were sampled at two depths, 0 – 15 and 15 – 35 cm. Soil parameters analyzed included particle size distribution (%), bulk density (g/cm3), pore space (%), moisture content (%), pH in water and in potassium chloride solution, EC (μS/cm), organic matter (%), CEC (meq/100g), exchangeable bases: Ca++(cmolc/kg), Mg++(cmolc/kg), K+(cmolc/kg), Na+(cmolc/kg); nitrogen: NH4-N (mg/kg), NO3-N (mg/kg), TKN (%), and Olsen P (mg/kg). Results showed a direct correlation between length of active kraal utilization and impact of animal waste concentration on the soil with correlation coefficients as high as r = 0.99 and r = 0.95 for pH and OM respectively. Nutrient levels in kraal soils of all ages were significantly higher (P = 0.05) than those of the control site soils. Most nutrient elements showed increases ranging from about 2 - 30 times greater than in the control site soils. Soil nutrient levels were higher in the dry season than in the wet season. The nutrient enrichment in the kraals extended deep into the soil, at least, to the 35 cm depth. The organic and nutrient enrichments of the soils also had very positive effects on soil moisture and structural characteristics. However, this highly localized nutrient enrichment of kraal soils is detrimental to the long term sustainability of arid ecosystems and soil productivity. The nutrients concentrated in kraals have been harvested from the surrounding areas by grazing animals and transferred to the kraal sites. In a situation of sedentary kraaling that exists in semi arid lands of Botswana where rotation of kraal sites or the harvesting of animal manure from kraals for use as soil manure is not commonly practiced, the concentration of soil nutrients at scattered kraal spots causes an imbalance in the spatial pattern of soil and plant productivity in the arid land ecosystem. The entire ecosystem is made poorer by this phenomenon. Description: Full Length Research Paper URI: http://hdl.handle.net/10311/1095 Files in this item: 1
Kizza and 0Areola.pdf (293.8Kb) -
Moleele, N.; Ringrose, S.; Arnberg, W.; Lunden, B.; Vanderpost, C. (Taylor and Francis http://www.clas.ufl.edu/lueci/southworth/RS-class-advanced/Discussion-readings/Moleele%20et%20al%202001%20Assessment%20of%20veg%20indexes%20i.pdf, NaN, 2001)[more][less]
Abstract: Considerable signi® cance is placed on the mapping and monitoring of degraded areas in semi-arid regions of the world, including Botswana. Degraded areas include those suVering from bush encroachment, believed to result from heavy cattle grazing over a number of years. However, certain bush encroachment species have been found to be relatively nutrient-rich.The present work considers the extent to which a series of quanti® ed layers throughmainly bush encroachment canopies can be identi® ed using conventional and newly derived vegetation indexes and transforms based on Thematic Mapper (TM) imagery. Field work involved the strati® cation of green biomass into ® rstly the herbaceous cover layer; secondly the 0.3± 1.5m browse layer; then the 1.5± 2.5m browse layer; and ® nally the >2.5m browse layer. Biomass measurements from these layers were statistically associated with conventional vegetation indexes and transforms such as the NormalizedDiVerenceVegetation Index (NDVI), brightness and greenness values, and relatively newly derived darkening indexes involving the mid-infrared bands. When green biomass and transformed pixel data were averaged per classi® ed vegetation unit, weak negative correlations emerged between grass biomass and the transformed pixel data and no signi® cant correlations developed with the woody biomass (browse) layers. However, when point data were used in the analyses, results showed that most indexes and the brightness transform were signi® cantly correlated with the lower browse layer. Only the darkening indexes and brightness function were sensitive to the browse layers individually and the browse plus grass layers. This work shows the limitations of conventional indexes such as the NDVI in terms of browse and herbaceous layer assessment. New indexes for forage assessment based on relationships between the mid-infrared bands, such as those found in the new MODIS TERRA platform, are urgently required for semi-arid areas. URI: http://hdl.handle.net/10311/410 Files in this item: 1
Moleele_IJRS_2001.pdf (903.7Kb) -
Kayombo, B.; Meulenburg, F.; Moganane, B. G.; Dikinya, O.; Aliwa, J. N.; Nsinamwa, M.; Gaboutloeloe, G.; Patrick, C.; Mzuku, M.; Machacha, S. (University of Botswana, http://www.ub.bw, April NaN, 2005)[more][less]
Abstract: A study was carried out during 1998-2001 with the objective of, firstly, assessing the impact of cultivation on soil quality, and secondly, evaluating the effects of human and animal activities on soil erosion and range resources. A Topical Rapid Rural Appraisal (TRRA) based on rapid appraisal approaches, was conducted in three benchmark villages in Bobirwa Sub-district. A diagonistic survey report provided similar information for Kgalagadi District. Three benchmark sites were located in Bobirwa Sub-district and two others in Kgalagadi District. Soils were characterized at benchmark sites and in the laboratory for physiochemical properties. Soil erosion was monitored using embedded nail technique. At all benchmark sites, trends show a deterioration of soil quality, both in terms of nutrient depletion and poor physical properties for cultivated soils in comparison to uncultivated soils. There is visible evidence of environmental degradation of land resources resulting partly from considerable soil trampling and loosening during the dry season by livestock. During the wet season, the loosened soil is washed down elsewhere and/or deposited at watering points. The confounding effects of drought, overgrazing, poor management and ever-increasing utilization of veld products have led to the decline of a considerable number of tree and grass species. URI: http://hdl.handle.net/10311/645 Files in this item: 1
Kayombo_BJT_2005.pdf (3.655Mb) -
Dikinya, O.; Mufwanzala, N. (Academic Journals, http://www.academicjournals.org/JSSEM, May NaN, 2010)[more][less]
Abstract: The utilization of chicken manure as an organic fertilizer is essential in improving soil productivity and crop production. We carried out the study to assess the effects of chicken manure on soil chemical properties and the response of application rate on the yield of spinach (Spinacia oleracea) as well as the uptake of nitrogen and phosphorus nutrients. To quantify these effects, we added chicken manure to samples of Calcisols, Arenosols and Luvisols at application rates: 5, 10, 20 and 40% chicken manure. The addition of chicken manure irrespective of application rate did not change the acidity or pH of Calcisol, suggesting its hypo-buffering capacity. While the results reveal increases of EC with increasing rate, at rate above 40%, the ECs were above the critical salinity level of 4 mS/cm indicating potential threat to soil productivity. The exchangeable bases increased with application rate, suggesting the positive effects of chicken manure in enhancing soil fertility. Similarly significant increase of nitrogen and phosphorus were observed following the addition of chicken manure. Initially the spinach yield increases up to optimum rate of 0.06, 0.07 and 0.16 g/plant for Luvisol, Arenosol and Calcisol, respectively and subsequently drops after critical threshold values; 15, 5 and 1% for Calcisol, Arenosol and Luvisol, respectively. Interestingly above the rate of 40%, the yield was almost zero for all soils, suggesting the ineffectiveness of chicken manure in enhancing soil productivity. URI: http://hdl.handle.net/10311/1003 Files in this item: 1
Dikinya_JSSEM_2010.pdf (514.6Kb) -
Dikinya, O.; Areola, O. (Springer, http://link.springer.com/, March NaN, 2010)[more][less]
Abstract: The use of treated urban wastewater for irrigation is a relatively recent innovation in Botswana and knowledge is still limited on its impact on soil heavy metal levels. The aim of this study is to analyze and compare heavy metal concentration in secondary wastewater irrigated soils being cultivated to different crops: olive, maize, spinach and tomato in the Glen Valley near Gaborone City, Botswana. The studied crop plots have been cultivated continuously under treated wastewater irrigation for at least 3 years. Most crop farms have sandy loam, loamy sand soils. Based on food and agriculture organization, heavy metal threshold values for crop production have been studied. Results showed that the wastewater irrigated soils in the Glen Valley have higher cadmium, nickel and copper than desirable levels, while the levels of mercury, lead and zinc are lower than the maximum threshold values recommended for crop production. The control sites show that the soils are naturally high in some of these heavy metals (e.g copper, zinc, nickel) and that crop cultivation under wastewater irrigation has actually lowered the heavy metal content. Comparing between the crops, mercury and cadmium levels are highest in soils under maize and decline linearly from maize to spinach to olive to tomato and control site. By contrast, concentrations of the other metals are at their lowest in maize and then increase from maize to spinach to olive to tomato and to control site. URI: http://hdl.handle.net/10311/1105 Files in this item: 1
ijest 2010 dikinya and areola.pdf (685.3Kb) -
Moroke, T.S.; Dikinya, O.; Patrick, C. (Elsevier Science Ltd, http://www.elsevier.com/locate/pce, NaN, 2009)[more][less]
Abstract: Water infiltration is an important component of water balance for improving crop production potential in dryland soil tillage systems in Botswana, particularly in the eastern region. Hardsetting soils common in arable lands of Botswana, often require some kind of tillage such as mouldboard ploughing, chiselling and ripping to improve waterharvesting and crop growth conditions. The objective of this study was to compare ponded cumulative infiltration, steady state infiltration rate and sorptivity of soils cultivated using deep ripping, single and double mouldboard ploughing. This study was conducted on Chromic Luvisols (sandy loam), Haplic Luvisols (sandy clay loam), Ferric Luvisols (clay loam), and Ferric Arenosols (sand). Infiltration was measured using double ring infiltrometer method for 4 h. Although infiltration was smaller on traffic line of deep ripping system at all sites, it was only significantly (P < 0.05) different on Ferric Luvisols and Ferric Arenosols. Compared with conventional ploughing, steady state infiltration was greater but not significantly (P > 0.05) different under deep ripped. Cumulative and steady state infiltration rate was greater under sandy than loamy soils, smaller under double ploughing compared with single ploughed and deep ripped soils. Sorptivity was not significantly (P > 0.05) different among tillage systems but was greater under sandy than sandy loam soils. Information on tillage and infiltration can improve implementation of waterharvesting technologies and crop production in Botswana. URI: http://hdl.handle.net/10311/1007 Files in this item: 1
Moroke_PCE_2009.pdf (666.4Kb) -
Areola, O.; Dikinya, O.; Mosime, L. (Global Science Books, http://www.globalsciencebooks.info/Journals/AJPSB.html, NaN, 2011)[more][less]
Abstract: This study compares soil quality parameters, and salinity and heavy metal levels in soils cultivated with different crops under secondary treated wastewater irrigation in the Glen Valley, near Gaborone City, Botswana. The hypothesis being tested is that the impact of wastewater on soil quality varies with soils and crop types. The study covers 4 selected crops, maize (Zea mays L.), spinach (Spinacia oleracea), olive (Olea europaea), and tomato (Solanum lycopersicum), most widely cultivated by the farmers. Three farm plots per crop type were sampled at 5 sampling points and at two soil depths, 0-15 and 15-30 cm. Samples were also collected at 5 sampling points from two control sites. Irrigation water samples were collected from microbiological analysis from 2 farms per crop type. The most significant differences and relationships are between those crop farms, such as maize and two of the spinach plots, with predominantly sandy soils (loamy sands – sand loams) on the one hand, and the olive, tomato and one of the spinach plots with sandy clay loams on the other. The importance of soil texture was confirmed by the strong correlations between the sand and silt contents, several soil quality parameters, heavy metals and other elements. With the exception of Cd and Hg, most soil heavy metal contents were lower on the irrigated plots than on the control plot. The EC values also show that soil salinity levels were still low on the irrigated fields, but SAR and ESP values were high. The secondary treated wastewater being used in the Glen Valley is biologically clean, but one recorded case of E. coli emphasizes the importance of avoiding sprinkler irrigation at all costs to protect human health. URI: http://hdl.handle.net/10311/1002 Files in this item: 1
Dikinya_AJPSB_2011.pdf (249.7Kb) -
Mbaiwa, J. E.; Ngwenya, B.N.; Kgathi, D.L. (Blackwell http://www.wiley.com/10.1111/j.1467-9493.2008.00332.x, NaN, 2008)[more][less]
Abstract: This paper reviews how state policy and regulatory instruments, including protected area alienations and concessions, have altered or denied the access to land and natural livelihood resources of the indigenous Basarwa and minority subsistence-oriented communities in the Okavango Delta (OD) in Botswana. Drawing on field research and guided by a sustainable rural livelihoods framework, the paper provides an overview of key institutional interventions – in particular the setting up of the Moremi Game Reserve, Wildlife Conservation Policy, Tourism Policy, Agricultural Development Policy and the erection of veterinary fences – that have served to privilege a foreign-owned and dominated commercialized wildlife and nature tourism sector and the export-oriented beef industry in the OD. The officially sanctioned barriers to customary and usufructory rights and access, and the non-recognition of historically embedded traditional land uses have decimated already marginalized resource-based subsistence livelihoods, and precipitated intergroup conflicts over preferential rights and access to resources and opportunities, notably wildlife, non-timber veld products, agriculture and community-based tourism schemes. Such outcomes, moreover, will have consequences for the longer-term sustainability of the OD both as a socioeconomic resource base and as a natural ecosystem. URI: http://hdl.handle.net/10311/483 Files in this item: 1
Mbaiwa_SJTG__2008.pdf (966.6Kb) -
Mbaiwa, J.E.; Sakuze, L. K. (Taylor and Francis http://dx.doi.org/10.1080/14766820902829551, NaN, 2009)[more][less]
Abstract: This paper uses the livelihoods framework to analyse how cultural tourism can diversify livelihoods at XaiXai village in the Okavango Delta, Botswana. Both primary and secondary data sources were used in this study. Primary data sources included household and key informant’s interviews conducted at XaiXai village and Gcwihaba Caves. Secondary data included both published and unpublished materials on cultural tourism, XaiXai village and Gcwihaba Caves. Results indicate that the San(Basarwa) of XaiXai’s traditional life of hunting and gathering has become a cultural tourism product in the Okavango Delta. Gcwihaba Caves’ geological formation particularly the stalagmites, stalactites and channels also attract tourists that visit the Okavango Delta. The caves also have a cultural history in that they were used as a hiding place by the Basarwa in times of wars, rainy season and cold winters. As such, the cultural values of the San of XaiXai and Gcwihaba Caves are cultural tourism products that can diversify livelihoods at XaiXai village. Therefore, policies and strategies that address cultural tourism and rural livelihoods in tourism destination areas need to be developed. The Gcwihaba Caves and Xaixai Village case study demonstrates that cultural tourism can be a tool for rural livelihoods diversification in tourism destination areas of developing countries. URI: http://hdl.handle.net/10311/482 Files in this item: 1
Mbaiwa_JTCC_2009.pdf (899.2Kb) -
Meck, M.; Atlhopheng, J.; Masamba, W.R.L. (Elsevier http://www.linkinghub.elsevier.com/retrieve/pii/S1464343X09000491, NaN, 2009)[more][less]
Abstract: Alkaline rocks (phosphate deposits in particular) of igneous origin are currently being mined in Zimbabwe. Exploitation of these deposits, which are associated with metals and non-metals, provides a potential for changing the river water quality in the surrounding areas by increasing metal and phosphates levels in the water, thereby endangering the beneficial use of the river. The aim and objectives of this paper are to enumerate the current impacts associated with mining alkaline rocks on Save River water quality in Zimbabwe using the Dorowa mine as a case study. Though there are several impacts associated with the mining of alkaline rocks, this paper deals only with impacts on water quality. A preliminary assessment of the water quality in the Save River downstream of the Dorowa phosphate mine showed an increase in conductivity, iron content, manganese content, nitrates and hardness when compared to those taken before mining activity began. However, there was no notable increase in phosphate and metals except for Fe and Mn. A plausible explanation for the low phosphate values in the water is that the phosphates are precipitating and settling as sediments. Phosphate is known to effectively remove metals from the surface water through the formation of metal–phosphate minerals. Thus, various pollutants may be adsorbed into sediments accumulated on the bottom of the river. These sediments may accumulate pollutants over long periods and act as new pollutant sources to the overlying water when phosphate desorbs from sediments due to changes in water conditions. Therefore, the sediments can act as a source of water pollution in the future URI: http://hdl.handle.net/10311/409 Files in this item: 1
Meck_JAES_2009.pdf (495.8Kb) -
Dikinya, O.; Hinz, C.; Aylmore, G. (Elsevier http://www.linkinghub.elsevier.com/retrieve/pii/S0016706108001365, NaN, 2008)[more][less]
Abstract: The dynamics of the process of self-filtration in soil columns have been evaluated for two soils with different structural cohesion (Balkuling agricultural soil and a mining residue) by carrying out experiments focusing on microscopic particle behaviour during filtration. Soil column experiments were set up to simultaneously measure changes in hydraulic gradients (ΔH/ΔL) along the columns and outflow particle sizes and concentrations during pressure leaching with solutions of 100, 10 and 1 mmol/L NaCl and deionised water. The lowest ionic strength has resulted in more reduced hydraulic conductivity and relatively more release of colloids associated with hydrodynamic shear and dispersion. Steady increases in hydraulic gradient (ΔH/ΔL) and corresponding decreases in relative saturated hydraulic conductivity (K/Ko) with time were observed for both soils and follow similar trends at all column depths. The most severe increases in ΔH/ΔL and decreases in K/Ko always occurred near the inlet to the columns and the decline gradually decreased along the column. The decrease in K/Ko and increase in ΔH/ΔL were clearly influenced by the size as well as the concentration of migrating particles in the porous medium. The finer mobile particles in the mining residue were clearly more readily self-filtered at the lower concentration than the larger Balkuling soil particles producing more rapid increases in ΔH/ΔL and decreases in K/Ko. This was attributable to more effective self-filtration and more pore clogging probably due to increased development of the diffuse double layer, swelling and dispersion within the soil matrix at these concentrations. URI: http://hdl.handle.net/10311/488 Files in this item: 1
Dikinya_Geoderma_2008.pdf (1.429Mb) -
Bernard, T.; Moetapele, N. (Elsevier http://www.doi:10.1016/j.jaridenv.2005.02.001, NaN, 2005)[more][less]
Abstract: For at least 200 years, Gomoti River people and their neighbours lived interactively with the Okavango flood pulse system, travelling widely in dugout canoes, practicing flood recession agriculture, fishing, hunting, and collecting wild foods. Today they are wetlanders without wetlands. A major outflow channel of the eastern Okavango Delta in the 1930s, the Gomoti River rarely flows these days. This paper explores the Gomoti’s demise, through the lenses first of science and second of Gomoti basin residents. Models developed over the past 20 years attribute the Gomoti’s drying to a complex set of bio-hydrologic processes and feedback loops that begin with sedimentation and conclude with channel switching, peat fires, and purging of toxic salts. Such models essentially omit the long history of human habitation and ecological interaction with the delta. Local people, on the other hand, tell of deliberate and systematic management of channels and floodplains, and they argue this management kept the river healthy and flowing. The picture is confounded by colonial era interventions and by Botswana government policies partitioning the Gomoti and restricting access to its headwaters. We conclude with a model combining meso-scale scientific explanation with micro-scale indigenous constructions as a context for new thinking about Okavango Delta resource management. URI: http://hdl.handle.net/10311/467 Files in this item: 1
Bernard_JAE_2005.pdf (2.556Mb) -
Toteng, E.N. (Routledge http://dx.doi.org/10.1080/02508060802475415, NaN, 2008)[more][less]
Abstract: This article examines the adverse effects of a fragmented water management framework and the role of domestic water users on water conservation in Gaborone, the rapidly growing capital city of Botswana. There was a major drought in Botswana in 2004, which recurred in 2007. The drought seriously affected water availability in Gaborone, re-igniting the water conservation debate. Most urban households prior to 2004 did not practise water conservation, except in cases of enforced temporary measures, such as water restrictions and increased water tariffs imposed by the Water Utilities Corporation. From secondary evidence, the situation had not changed much in 2007. URI: http://hdl.handle.net/10311/363 Files in this item: 1
Toteng_WI_2008.pdf (851.6Kb) -
Mbaiwa, J.E. (Elsevier http://www.doi:10.1016/j.tourman.2003.11.005, NaN, 2005)[more][less]
Abstract: This paper draws on the dependency paradigm to explain the development of enclave tourism and its socio-economic impacts in the Okavango Delta, Botswana. Using both primary and secondary data source, the study indicates that international tourists, foreign safari companies and investors dominate the tourism industry in the Okavango Delta. The foreign domination and ownership of tourism facilities has led to the repatriation of tourism revenue, domination of management positions by expatriates, lower salaries for citizen workers, and a general failure by tourism to significantly contribute to rural poverty alleviation in the Okavango region. Tourism as a result has a minimal economic impact on rural development mainly because it has weak linkages with the domestic economy, particularly agriculture. Because of its nature, tourism in the Okavango Delta cannot be described as being sustainable from a socio-economic perspective. In order to address problems of enclave tourism development and promote more inclusive and beneficial tourism development in the Okavango, there is need to adopt policies and strategies that will ensure that substantial amounts of tourism revenue are retained in the Okavango and Botswana. These strategies should also ensure that tourism development in the Okavango Delta has strong linkages with the rest of the economy in Botswana. URI: http://hdl.handle.net/10311/429 Files in this item: 1
Mbaiwa_TM_2005.pdf (2.402Mb) -
Gwebu, T.D. (Kluwer Academic Publishers, http://www.springerlink.com/content/102895/, NaN, 2002)[more][less]
Abstract: Like most African countries, Botswana contributes almost insignificantly to global greenhouse emissions (GHGs). In this context, some have argued that energy policy and legislative measures to regulate emissions in Botswana should not be accorded high priority. This is a misguided view when one considers that each country, no matter how under-industrialized, contributes to the overall global emission problem. Moreover, the least developed countries will have to industrialize in order to meet the increasing economic and social needs of their growing populations. For rapidly growing economies like Botswana, whose annual energy demand is projected to increase by about 4% for the next ten years, the importance of compiling accurate inventories of sources and sinks of GHGs and formulating environmentally-friendly policies can hardly be over- emphasized. The United Nations Framework Convention on Climate Change (UNFCCC) provides the ideal basis for the country-by-country investigations and management of global climatic change; specifically its nature, properties, directionality, characteristics and probable consequences. Botswana was a founding signatory of UNFCCC in 1992 and ratified the Convention in 1994. The country is also involved in regional cooperation efforts, within the Southern African Development Community, to enforce regulatory mechanisms to minimize GHG emissions from the energy sector. There exist certain energy-related institutions, policies, and regulations in the country which could mitigate the impact of GHG emissions on global warming. This paper, based on government and other relevant documentation, critically analyses Botswana’s energy sector policies in as far as they affect climate change. It is clear that much still needs to be done about energy policies in terms of proper formulation, monitoring, co-ordination, energy pricing and the exploration of energy alternatives to mitigate potentially negative impacts on climate change. URI: http://hdl.handle.net/10311/958 Files in this item: 1
Gwebu_GJ_2002.pdf (1.010Mb) -
Totolo, O.; Chanda, R. (Elsevier Science Ltd, http://www.elsevier.com/wps/find/journaldescription.cws_home/622855/description#description, NaN, 2003)[more][less]
Abstract: The collection of papers in this special edition of the Journal of Arid Environments is a sequel to a Workshop held in Maun, Botswana, in October 2000, on the theme Climate Change, Biodiversity and Multi-species Production Systems in the Kalahari Region. Constituting only about one-third of the workshop papers delivered, this set of articles survived a rigorous peer-review process and are being published as one of the planned outputs of the Maun meeting. Except for the keynote paper by Darkoh which is a review article with a continental purview, the collection is based on research conducted by natural and social scientists within the Southern African Kalahari region either as part of the Southern African Science Initiative (SAFARI 2000) co-ordinated from the University of Virginia in the U.S.A. or of the Kalahari Transect project based at the University of Botswana. URI: http://hdl.handle.net/10311/316 Files in this item: 1
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Gwebu, T.D. (Pergamon, www.elsevier.com/locate/habitatint, NaN, 2003)[more][less]
Abstract: This study investigates the profile, dynamics and dimensions ofenvironm ental problems at Old Naledi, a low income urban neighbourhood in Gaborone, the capital city ofBotsw ana. It is based on documentary and field research. The field research has a participatory component involving meetings, discussions and open- ended interviews with the interested and affected persons. It also involves the administration of a structured survey questionnaire to 171 resident respondents. The main findings ofthe study are that residents have made great efforts in improving the availability of the housing stock. However, in the process they have failed to abide by the stipulated Development Control code and Urban Development Standards. This essentially reflects the increasing non-affordability of land and costs of construction materials to urban low income groups due to evolving state policy in the provisioning ofshelt er. The direct result has been a congested, overcrowded settlement. Because ofthis , and a rapidly increasing population, there has been underservicing and the emergence oflif e-threatening home and neighbourhood environmental problems. URI: http://hdl.handle.net/10311/496 Files in this item: 1
GWEBU2003Environmental Problems.pdf (2.409Mb) -
Gumbricht, T.; Wolski, P.; Frost, P.; McCarthy, T.S. (Elsevier http://www.doi:10.1016/j.jhydrol.2003.11.010, 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 coming decades. URI: http://hdl.handle.net/10311/428 Files in this item: 1
Gumbricht_JH_2004.pdf (1.267Mb) -
Mubyana, T.; Krah, M.; Totolo, O.; Bonyongo, M. (Journal of Arid Environments. http://www.elsevier.com/wps/find/journaldescription.cws_home/622855/description#description, NaN, 2003)[more][less]
Abstract: The effect of flooding on soil total nitrogen, phosphorus and microbial population in different vegetation zones (floodplain, island and woodland) and profile depth (0?1, 0?5, 2?0, 3?0, 4?0 and 5?0m) of the Okavango Delta was studied from February to July 1999. Total nitrogen significantly differed with soil profile depth, moisture regime and months. In the woodlands, insignificant total nitrogen was detected at all depths except at 0?1m, where 0?03% and 1?17% were detected in February and March, respectively. In the island samples, only 0?05% was detected at 4m in February. Nitrogen in the floodplain samples was concentrated in the A1 horizon where 0?12%, 0?61% and 0?03% were detected in February, March, and May, respectively. Organic phosphorus significantly differed with vegetation zone but not with months and depth. Although organic phosphorus was low (0?02–0?52%) at all sites, it was liberally distributed throughout the profiles. On the island, actinomycetes were only detected up to 2m in February and up to 3m in July. Fungi concentrated in the top 0?5m (103–105). In both the floodplain and island samples, bacteria concentrated in the upper 3m. However, after May, populations decreased significantly. In the floodplain, significant actinomycetes populations were only detected in the upper 0?5m. Generally, organic phosphorus showed positive correlations with fungal populations. This study indicates that these soils are low in total nitrogen and phosphorus. URI: http://hdl.handle.net/10311/293 Files in this item: 1
Influence of seasonal flooding.pdf (3.953Mb)
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