Browsing Research articles (ORI) by Issue Date
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Ringrose, S.; Vanderpost, C.; Matheson, W. (Taylor & Francis; http://www.tandf.co.uk/journals/titles/01431161.asp, NaN, 1997)[more][less]
Abstract: Attention worldwide has been focused on the need to assess the appropriateness of land management strategies especially where these occur near sensitive areas of wildlife habitat. This work considers the use of mainly Thematic Mapper data in providing an assessment of the relative impact of different land management strategies on the natural vegetation cover in part of the sensitive Okavango area in Botswana. Supervised classification (maximum likelihood) techniques when used on six-band TM imagery showed that differential degradation was prevalent in land management areas, especially where these are separated by fencelines with an overall accuracy 72 per cent. Marginally more degradation is evident in a controlled hunting area adjacent to the Game Reserve, relative to a communal grazing area. Band transform analyses indicate that distinctive changes in cover type and density frequently take place over boundaries or fencelines separating land management areas. Some degradation in the controlled hunting area appears related to the influence of faultlines on the distribution of soil, hence plant community types. In other cases the pattern of degradation is distributed randomly between the Game Reserve and the cordon fence. Reasons for this unusual distribution pattern may lie in the restriction of movement of migratory wildlife species southwards by the cordon fence separating communal grazing from hunting land uses. A more appropriate management strategy may lie in the prediction of wildlife movements, prior to the erection of cordon fences URI: http://hdl.handle.net/10311/173 Files in this item: 1
ringrose_int_j_remote_sensing_1997.pdf (4.553Mb) -
Otter, L.B.; Scholes, R.J.; Dowty, P.; Privette, J.; Caylor, K.; Ringrose, S.; Mukelabai, M.; Frost, P.; Hanan, N.; Totolo, O.; Veenendal, E. (Wageningen Institute for Environment and Climate Research, http://library.wur.nl/, NaN, 2002)[more][less]
Abstract: The Southern African Regional Science Initiative (SAFARI 2000) involved two wet season and one dry season field campaigns. This paper reports on the wet season campaigns. The first was conducted at five sites along the Kalahari Transect in Zambia (Kataba Forest) and Botswana (Pandamatenga, Maun, Okwa River Crossing, Tshane) during February 2000 and concentrated primarily on characterizing the land surface with respect to exchanges of matter and energy with the atmosphere. The second, conducted in February 2001, focused on fluxes of water, gases and energy between the canopy and the atmosphere at Maun, Botswana, and at Skukuza in the Kruger National Park, South Africa. Eddy covariance measurements at Skukuza and Maun were designed to collect a near-continuous record of the seasonality and inter-annual variability in savanna carbon, water and energy exchanges in representative savanna ecosystems. This paper gives brief descriptions of the sites, the measurements made, and the methods used. It highlights some preliminary results, particularly from the first campaign, and outlines the next stages of the SAFARI 2000 project URI: http://hdl.handle.net/10311/1031 Files in this item: 1
Otter_ Southern_africa_2002.pdf (1.002Mb) -
Moleele, N.M.; Ringrose, S.; Matheson, W.; Vanderpost, C. (ScienceDirect, www.sciencedirect.com, NaN, 2002)[more][less]
Abstract: the cattle-dominated grazing areas of Botswana. Bush encroachment species – for instance Acacia tortilis, A. erubescens, A. mellifera, Dichrostachys cinerea, Grewia flava, and Terminalia sericea –are increasing in cover and density around foci points (e.g. water points and kraals) at the expense of the grass cover. A number of factors have the effect of encouraging the germination and survival of bush encroachment species. The practice of cattle husbandry and continual shifting of foci points within grazing areas have resulted in the spread of the distribution of bush encroachment species across the country. This is evidenced by the potential extent of 37 000 km2 (6 4% of Botswana) of darkened and near infrared (NIR) reflective bush encroached areas in 1994. This paper suggests that specific management strategies should be adopted to help overcome the bush encroachment problem, which is causing a significant reduction in the extent of Botswana’s high quality rangeland. These strategies may vary from the enforced reduction of grazing intensity in areas identified as being heavily bush encroached to the selective management of opportunistic (communal) grazing in better quality predominantly grassland areas. Further work is however required to update this analysis and especially to consider trends since 1994–1995. While some work on the extent of woody cover and the further causes of bush encroachment is being undertaken under the SAFARI2000 project, more research is needed in specific areas to pinpoint causes and responses to the bush encroachment problem. URI: http://hdl.handle.net/10311/985 Files in this item: 1
Moleele_ et al_More_Woody_2002.pdf (3.119Mb) -
Ringrose, S.; Kampunzu, A.B.; Vink, B.W.; Matheson, W.; Downey, W.S. (John Wiley & Sons, Ltd. http://www3.interscience.wiley.com/journal/117935722/grouphome/home.html, NaN, 2002)[more][less]
Abstract: Quaternary sedimentation in the Moshaweng dry valley of southeastern Botswana is evaluated on the basis of geomorphological evolution and sedimentological analyses. Stratigraphic evidence reveals an 'upper surface (1095 m) containing abundant sil-calcrete, an intermediate surface (1085 m) in which sil-calcrete underlies nodular calcrete and lower (1075 m) surface in which sil-calcrete and nodular calcrete are interbedded. This subdivision is reflected in the geochemical composition of the sediments which show an overall trend of decreasing Si02 content (and increasing CaC03 content) with depth from the highest to the lowest surface levels. The calcretes and sil-calcretes represent modifications of pre-existing detrital Kalahari Group sand and basal Kalahari pebbles which thinned over a Karoo bedrock high. Modification took place during wet periods when abundant Ca++ -rich groundwater flowed along the structurally aligned valley system. With the onset of drier conditions, water table fluctuations led to the precipitation of nodular calcretes in the phreatic layer to a depth of about 20 m. A major geochemical change resulted in the preferential silicification of the nodular calcrete deposits. Conditions for silica mobilization may be related to drying-induced salinity and in situ geochemical differentiation brought about by pebble dissociation towards the top of the sediment pile. As calcretization and valley formation progressed to lower levels, silica release took place on a diminishing scale. Thermoluminescence dating infers a mid-Pleistocene age for sil-calcrete formation suggesting that valley evolution and original calcrete precipitation are much older. Late st~ge dissolution of CaC03 from pre-existing surface calcretes or sil-calcretes led to the formation of pedogenic case-hardened deposits during a time of reduced flow through the Moshaweng system possibly during the upper or late Pleistocene. URI: http://hdl.handle.net/10311/310 Files in this item: 1
Ringrose_ESPL_2002.pdf (3.095Mb) -
Sekhwela, M.B.M. (Elsevier Science Ltd, http://www.elsevier.com/locate/cag, July 22, 2002)[more][less]
Abstract: This paper investigated changes in economically important woody vegetation resources around seven settlements located along an aridity gradient in the Kalahari. Available data at different rainfall levels were analysed for different vegetation aspects. Total woody plant density and number of species at each site increased with increasing rainfall level, while individual species density differed at each site irrespective of rainfall, due to other factors, for example, land use as indicated by high stump densities around old and high population settlements. Drought resulted in high mortality of certain species, increasing availability of fuelwood resource in the form of dead wood. However, prolonged drought from climatic changes could result in browse shortage, a vital resource in the Kalahari. There was generally low wood resource availability throughout the studied gradient, without any distinct relation to rainfall, reflecting the influence of other factors such as soils, land use and natural variability. URI: http://hdl.handle.net/10311/1024 Files in this item: 1
Sekhwela M.B.M_2002.pdf (552.9Kb) -
Bond, J.M.; Veenedaal, E.M.; Hornby, D.D.; Gray, A.J. (Kluwer Academic Publishers, http://www.springerlink.com, November 28, 2002)[more][less]
Abstract: One of the major problems in determining the origin of invasive species is that often their arrival is unnoticed. Only when population levels increase is their presence noticed but by this time determining the point of arrival is confounded by the extensive spread of the species. Here we use molecular markers (ISSRs) to determine the origin of an invasive weed in the Kalahari region, a species for which several origins could be possible. We show that molecular markers can be useful tools in determining the origin of invasive species. URI: http://hdl.handle.net/10311/1025 Files in this item: 1
Bond_2002.pdf (2.049Mb) -
Swatuk, L.A. (Elsvier, www.elsevier.com, NaN, 2003)[more][less]
Abstract: This paper explores possibilities for achieving 'wise use’, defined as the sustainable utilization of resources of the Okavango Delta system, within the framework of the Ramsar Convention on Wetlands of International Importance. The paper argues that while the Ramsar Convention’s wise use strategic plan forms an important basis for collective action toward sustainably managing the Okavango River Basin as a whole, there are numerous barriers to success, the most important of which is the abiding behaviour of the region’s state-makers in defense of sovereignty and pursuit of narrow national interest. In spite of this formidable barrier to success, the paper highlights a number of on-going multilateral activities that may serve to further the aims of wise use of the Okavango River Basin system. It also provides a number of practical suggestions for furthering progressive frameworks of action. The paper is based on a close reading of published and unpublished written materials and the findings of a number of open-ended interviews conducted with stakeholders active in the Okavango River Basin. URI: http://hdl.handle.net/10311/988 Files in this item: 1
Swatuk_state Interests_2003.pdf (2.238Mb) -
Aranibar, J.N.; Anderson, I.C.; Ringrose, S.; Macko, S.A. (Elsvier, www.elsevier.com, NaN, 2003)[more][less]
Abstract: Cyanobacterial soil crusts may be important in arid and semi-arid ecosystems because of their ability to fix atmospheric nitrogen (N2). These crusts are very sensitive to trampling by animals, and their destruction can decrease ecosystem N inputs, affecting the productivity of the region. The objective of this study was to quantify the nitrogen-fixing activity in soil crusts during the wet season in southern African ecosystems using in situ acetylene reduction assays. The average acetylene reduction rates for each site ranged from 88 to 535 nmol m-2 h-1, were highly variable, and were lower than previously reported for other arid areas. All soil samples showed acetylene reduction activity; however, soils with crusts supported higher rates than did "non-crusty" soils under litter, moss, or sand. High values of 15N natural abundance (delta15N) indicated that processes other than N fixation were more important in the crusts than N fixation. For example, coupled and ammonia volatilization or atmospheric deposition of 15N-enriched nitrate or ammonium may have caused shifts in delta15N within the soil crusts. The estimated annual N fixation rates ranged from 8 to 44 g N ha-1 year-1, orders of magnitude lower than values estimated in other studies. The anomalous wet conditions experienced during the year of the study may have increased the temporal availability of soil mineral N and decreased N fixation rates. However, the presence of N fixation activity in all crusts analysed and their ability to survive at high temperature and after long dry periods may provide ecosystem resilience, facilitating ecosystem recovery after severe droughts. URI: http://hdl.handle.net/10311/983 Files in this item: 1
Ringrose_Importance_of_Nitrogen_2003.pdf (2.069Mb) -
Ringrose, S.; Matheson, W.; Wolski, P.; Huntsman-Mapila, P. (Elsevier; www.elsevier.com/locate/jaridenv, NaN, 2003)[more][less]
Abstract: Vegetative response aspects of climate change studies include the determination of vegetation cover changes across climatic gradients. Vegetation characteristics and soil moisture measurements were obtained from four locations with decreasing rainfall along the Botswana Kalahari transect. These are referred to as Pandamatenga, (698mmyear_1), Maun (460 mmyear_1), Okwa (407 mmyear_1) and Tshane (365 mmyear_1). Trends in major vegetative cover and soil components included species types and richness assessments which reflected certain changes southward but also showed interesting degrees of variability. This occurred despite the apparent homogeneity of the Kalahari sands and predominantly semi-arid savanna shrubâ woodland vegetation cover. Despite linear decreases, both in rainfall and soil moisture content, results indicated high soil moisture variability at the Okwa location which relates to unique climatic and geological factors. Also many species are unique to specific locations for instance Pandametanga is characterized by Zambesian species while the Maun location is characterized by Colophosphermum mopane. This changes southwards as Acacias become more dominant and significantly co-occur with Grewia flava. While the average total numbers of plants decreased, total numbers of different species varied little from the wetter to the drier end of the moisture gradient. The association between rainfall and woody cover is negative implying that canopy cover extents (in terms of vegetation density) increase along the gradient due to increases in bush encroachment in drier areas. Therefore, while representing a continuum in terms of species numbers, in other respects (e.g. species types and ground cover components) vegetation zones in the Kalahari may be regarded as discontinuous units. Differences between mapped vegetation zones may be accounted for in terms of relatively unique ecosystem factors which function partly in response to geological conditions and partly in response to local (as opposed to regional) climatic factors. This appears to have led to ecosystem adaptive measures (in terms of species responses) rarely mirrored elsewhere along the gradient. Hence adaptability in terms of species migrations in response to relatively rapid climate changes may not readily take place over the Kalahari in Botswana. URI: http://hdl.handle.net/10311/175 Files in this item: 2
license.txt (1.998Kb)ringrose_jae_2003.pdf (3.823Mb) -
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) -
Andersson, L.; Gumbricht, T.; Hughes, D.; Kniveton, D.; Ringrose, S.; Savenije, H.; Todd, M.; Wilk, J.; Wolski, P. (Elsvier, www.elsevier.com, September 8, 2003)[more][less]
Abstract: As part of the EU-funded project ‘Water and Ecosystem Resources in Regional Development––Balancing Societal Needs and Wants and Natural Resources Systems Sustainability in International River Basin Systems’ (WERRD) (www.okavangochallenge.com), work is carried out aiming to improve and develop scientific methods that will facilitate the understanding of fluctuations of hydrological and ecosystem variables and likely human-induced trends concerning key characteristics of the Okavango River Basin in Southern Africa. URI: http://hdl.handle.net/10311/980 Files in this item: 1
Andersson_PhysChemEarth_2003_Pw.pdf (1.840Mb) -
Gieske, A.S.; Wubett, M.T.; Timmermans, W.J.; Parodi, G.N.; Wolski, P.; Arneth, A. (SPIE, http://link.aip.org, NaN, 2004)[more][less]
Abstract: Land surface temperatures are important in global change studies, in estimating radiation budget, heat balance studies and as control for climate models. Several algorithms for estimating land surface temperature and emissivity spectra for multispectral thermal infrared images were developed recently for use with data from the Advanced Spacebome Thermal Emission and Reflection Radiometer (ASTER) on the TERRA platform. Similar methods are also used with the MODIS instrument. In this study, surface temperature and broadband emissivities were determined from the five TIR channels of ASTER instrument in an area on the southern fringe of the Okavango Delta (Botswana). MODTRAN 4 was used to determine the necessary atmospheric corrections while software was developed to facilitate MODTRAN post-processing. The results were compared with micrometeorological observations from a flux tower, with a LANDSAT 7 image of the same day, and finally also with reported ASTER surface temperature and emissivities for the same image (high level ASTER product). Results indicate that the surface temperature depends rather sensitively on atmospheric transmissivity and relatively large temperature differences are found between results from imagery analysis and flux tower. No relation was found between broad-band emissivity and NDVI, contrary to earlier findings in Botswana. URI: http://hdl.handle.net/10311/1015 Files in this item: 1
gieske_procSPIE_2003_pw.pdf (317.2Kb) -
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) -
Mbaiwa, J.E. (Routledge, http://www.informaworld.com, NaN, 2004)[more][less]
Abstract: The objective of this article is to assess the socio-cultural impacts of tourism development in the Okavango Delta, Botswana. This paper largely relied on the research work and reports by the author in the Okavango Delta from 1998 to 2004. In all instances, both primary and secondary data sources were used. However, much of the paper is based on the results of a survey carried out between April 2001 and July 2002. Findings indicate that tourism development in the Okavango Delta has both positive and negative socio-cultural impacts. Some of the positive socio-cultural impacts include income generation and employment opportunities from both community-based tourism projects and safari companies, infrastructure development such as airport and airstrips, tarred roads, hotels, lodges and camps, the improvement of social services such as banking, health, telecommunications and access to electricity. The negative socio-cultural impacts include enclave tourism, racism, relocation of traditional communities, breaking up of the traditional family structure, increase in crime, prostitution, the adoption of the Western safari style of dressing and a traditionally unacceptable ‘vulgar’ language by young people. This article argues that tourism needs to be sensitive to local cultural norms and beliefs for it to be accepted by local people and promote sustainable development. This is possible if all the stakeholders (government, operators and local people) collaborate in policy formulation, implementation and monitoring. This can minimise the negative cultural impacts and instead promote the positive. URI: http://hdl.handle.net/10311/946 Files in this item: 1
Mbaiwa 2004 Tourism Culture.pdf (4.520Mb) -
Bird, M.I.; Veenendaal, E.M.; Lloyd, J.J. (John Wiley and Sons, www.wiley.com, NaN, 2004)[more][less]
Abstract: We present a study of soil organic carbon (SOC) inventories and δ13C values for 625 soil cores collected from well-drained, coarse-textured soils in eight areas along a 1000 km moisture gradient from Southern Botswana, north into southern Zambia. The spatial distribution of trees and grass in the desert, savannah and woodland ecosystems along the transect control large systematic local variations in both SOC inventories and δ13C values. A stratified sampling approach was used to smooth this variability and obtain robust weighted-mean estimates for both parameters. Weighted SOC inventories in the 0–5 cm interval of the soils range from 7 mg cm−2 in the driest area (mean annual precipitation, MAP=225 mm) to 41±12 mg cm−2 in the wettest area (MAP=910 mm). For the 0–30 cm interval, the inventories are 37.8 mg cm−2 for the driest region and 157±33 mg cm−2 for the wettest region. SOC inventories at intermediate sites increase as MAP increases to approximately 400–500 mm, but remain approximately constant thereafter. This plateau may be the result of feedbacks between MAP, fuel load and fire frequency. Weighted δ13C values decrease linearly in both the 0–5 and 0–30 cm depth intervals as MAP increases. A value of –17.5±1.0‰ characterizes the driest areas, while a value of −25±0.7‰ characterizes the wettest area. The decrease in δ13C value with increasing MAP reflects an increasing dominance of C3 vegetation as MAP increases. SOC in the deeper soil (5–30 cm depth) is, on average, 0.4±0.3‰ enriched in 13C relative to SOC in the 0–5 cm interval. URI: http://hdl.handle.net/10311/942 Files in this item: 1
Bird Veneendaal 2004.pdf (1.620Mb) -
Veenendaal, E.; Kolle, O.; Lloyd, J. (Blackwell publishing, www.blackwellpublishing.com, NaN, 2004)[more][less]
Abstract: We studied the seasonal variation in carbon dioxide, water vapour and energy fluxes in a broad-leafed semi-arid savanna in Southern Africa using the eddy covariance technique. The open woodland studied consisted of an overstorey dominated by Colophospermum mopane with a sparse understorey of grasses and herbs. Measurements presented here cover a 19-month period from the end of the rainy season in March 1999 to the end of the dry season September 2000. During the wet season, sensible and latent heat fluxes showed a linear dependence on incoming solar radiation (I) with a Bowen ratio (β) typically just below unity. Although β was typically around 1 at low incoming solar radiation (150 W m−2) during the dry season, it increased dramatically with I, typically being as high as 4 or 5 around solar noon. Thus, under these water-limited conditions, almost all available energy was dissipated as sensible, rather than latent heat. Marked spikes of CO2 release occurred at the onset of the rainfall season after isolated rainfall events and respiration dominated the balance well into the rainfall season. During this time, the ecosystem was a constant source of CO2 with an average flux of 3–5 μmol m−2 s−1 to the atmosphere during both day and night. But later in the wet season, for example, in March 2000 under optimal soil moisture conditions, with maximum leaf canopy development (leaf area index 0.9–1.3), the peak ecosystem CO2 influx was as much as 10 μmol m−2 s−1. The net ecosystem maximum photosynthesis at this time was estimated at 14 μmol m−2 s−1, with the woodland ecosystem a significant sink for CO2. During the dry season, just before leaf fall in August, maximum day-and night-time net ecosystem fluxes were typically −3 μmol m−2 s−1 and 1–2 μmol m−2 s−1, respectively, with the ecosystem still being a marginal sink. Over the course of 12 months (March 1999–March 2000), the woodland was more or less carbon neutral, with a net uptake estimated at only about 1 mol C m−2 yr−1. The annual net photosynthesis (gross primary production) was estimated at 32.2 mol m−2 yr−1. URI: http://hdl.handle.net/10311/937 Files in this item: 1
Veenendal 2004 GCBiology.pdf (2.375Mb) -
Mbaiwa, J.E. (John Wiley and Sons, http://www.wiley.com, NaN, 2004)[more][less]
Abstract: This paper uses the concept of sustainable rural livelihoods and income diversification to assess the role that basket making as a cultural tourism activity can play in improving rural livelihoods in the Okavango Delta, Botswana. Using both primary and secondary data sources, this paper points out that shocks and natural causes such as drought, disease and changing flood levels in the Okavango River, particularly the drying of the Thaoge (one of the distributaries of the Okavango), have contributed to a decline in livestock and crop yields and increased poverty levels in the region. Therefore, alternative livelihood options that can diversify rural incomes from agricultural production need to be identified. This paper argues that basket making has the potential to diversify rural incomes and improve livelihoods in the Okavango. Baskets are a cultural tourism product that can raise income earning and employment opportunities for rural residents in the Okavango. For this to be successful, basket making will need to be developed as part of cultural tourism. A sustainable cultural tourism sector where baskets are key products requires the sustainable use of natural resources used for basket making. These resources are at present overharvested and are threatened with depletion. There is also a need to promote the empowerment of basket weavers particularly in entrepreneurship and managerial skills in the tourism business, attract young and educated people and promote the preservation of traditional basket making skills, which are important in the development of cultural tourism. URI: http://hdl.handle.net/10311/935 Files in this item: 1
Mbaiwa 2004 Int Journ Tourism.pdf (3.700Mb) -
Mbaiwa, J.E. (Elsevier, www.elsevier.com, NaN, 2004)[more][less]
Abstract: This paper reviews available literature concerning water resources use in the Okavango River Basin (ORB). It describes a number of common arguments regarding possibilities for the emergence of violent conflict in and among Basin states, particularly those states party to the Okavango River Basin Commission (Okacom)—Angola, Botswana and Namibia. The paper presents data concerning present and future water demands and examines a number of formal, institutional steps taken by global and regional actors to facilitate sustainable development, natural resources management and peaceful cooperation in the Basin. Contrary to trends in much of the literature, the paper suggests that there is great scope for enhanced inter-state cooperation in the Basin. It argues that to achieve sustainable utilisation of water resources and avoid violent conflict in the ORB, an integrated management plan for the entire basin needs to be developed. In addition, each basin member-state should observe international and regional conventions and treaties governing the use of water resources when designing national water development projects that require the use of water from the ORB. URI: http://hdl.handle.net/10311/934 Files in this item: 1
Mbaiwa Causes and Solutions.pdf (1.775Mb) -
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) -
Mbaiwa, J.E. (Society of South African Geographers; http://www.journals.co.za/ej/ejour_sageo.html, NaN, 2004)[more][less]
Abstract: This paper assesses the success and sustainability of Community-Based Natural Resource Management (CBNRM) in the Okavango Delta. It does so by asking the following questions: a) to what extent has CBNRM contributed to sustainable natural resource use, rural economic development, enhanced rural livelihoods and benefit sharing? b) To what extent has power been devolved to the rural communities especially in relation to resource ownership and management? c) What are the existing and potential challenges facing the successful implementation of CBNRM in the Okavango Delta? With illustrations from the three CBNRM projects of Okavango Community Trust, Okavango Kopano Mokoro Community Trust and the Khwai Development Trust, this paper notes that local communities have successfully established community trusts as institutions to provide leadership in their participation in tourism and natural resource management. They also derive socio-economic benefits from CBNRM such as the participation in decision-making, employment and income generation. However, the lack of entrepreneurships and managerial skills, understanding of the concept of CBNRM, poor benefit sharing on CBNRM participants, and enclave tourism are some of the challenges that face CBNRM in the Okavango Delta. In the event that empowerment issues especially training and capacity building are successfully addressed, CBNRM in the Okavango Delta has the potential to be a successful model of community-based tourism. URI: http://hdl.handle.net/10311/157 Files in this item: 2
license.txt (1.998Kb)mbaiwa_sagj_2004_msm.pdf (111.4Kb)
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