Browsing Research articles (ORI) by Title
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Vanderpost, C. (Population Environment; Springer Netherlands; http://www.springerlink.com/content/0t141ml76q32717m/, January NaN, 2006)[more][less]
Abstract: Intensification of human sprawl in buffer zones of globally important African wilderness areas is of worldwide concern. The paper identifies two major conflicting (yet potentially reconcilable) pathways of rural sprawl in African wilderness buffer regions, described as the subsistence pathway and the wildlife-tourism pathway. Containment of rural sprawl near important ecological reserves requires addressing both pathways and their underlying conflicts. Reconciliation of subsistence sprawl with wildlife-conservation based tourism may occur through adequate compensation for community subsistence resource losses by the creation of sufficient alternatives to local communities that may reduce the need to rely on subsistence resources. URI: http://hdl.handle.net/10311/59 Files in this item: 2
cvanderpostpathwaysprefinalversion.pdf (725.4Kb)license.txt (1.998Kb) -
Meck, M.L.; Atlhopheng, J.; Masamba, W.R.L.; Ringrose, S. (Elsevier. http://www.elsevier.com, August 20, 2010)[more][less]
Abstract: The study set out to determine the weathering and dissolution of metal hosting minerals at Dorowa for purposes of deducing pollution potential to the nearby Save River. Phosphate rock is mined at Dorowa for the production of phosphate fertilizer. The major minerals found in the ring complex are feldspars, pyroxenes, apatite, magnetite and calcite. Chemical analysis established that the rocks are associated with metals that include copper, lead, zinc, cobalt, nickel, tin and cadmium. Among the many minerals present apatite and calcite host metals more than the other minerals due to their crystal structure. This study investigated the weathering and dissolution of these two minerals. Both apatite and calcite dissolve in natural environmental conditions prevalent at Dorowa. From the analysis the study concludes that the potential availability of metals trapped in the calcite and apatite structures is high. The understanding of weathering and dissolution of metal hosting minerals is important in predicting quality of water around the study area, because most villagers use the Save River as their primary drinking water source. URI: http://hdl.handle.net/10311/833 Files in this item: 1
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VanderPost, C.; Ringrose, S.; Seely, M. (Botswana Society, NaN, 2005)[more][less]
Abstract: Image processing in the upper Okavango catchment resulted in ten generalised classes which may be used as base line data for monitoring future overall land-use/cover change assessments over the entire upper catchment. Specific work was undertaken using single images for more detailed land-use/cover mapping in a 10 km buffer along all tributaries of the upper Okavango in Angola and Namibia. In terms of the under-developed Angolan upper catchment there is relatively little land clearing at present, and impacts on water use and quality are expected to be minimal in the near future. This is a consequence of 20 years of civil war, while the return of refugees is being inhibited by the prevalence of land-mines. Much more extensive development is taking place in Namibia along the southern bank of the Kavango river. This area is likely to become more intensively used as Namibia attempts to develop greater food security. Further work is required to monitor the impacts from Namibian agricultural expansion. These are likely to be pervasive in terms of the ecology of both the Mahango Game Reserve in Namibia and the Okavango Delta in Botswana. URI: http://hdl.handle.net/10311/936 Files in this item: 1
VanderPost 2005 Prelim.pdf (2.370Mb) -
Dallas, H.F.; Mosepele, B. (African Journal of Aquatic Science http://www.nisc.co.za/journals?id=2, NaN, 2006)[more][less]
Abstract: The spatial distribution of aquatic macroinvertebrates in the Okavango River Delta, Botswana, was investigated during the low-water period in February 2003. This complements an earlier study undertaken during high-water in June 2000. Seventy-five samples were taken in a range of aquatic habitats at 29 georeference points in four focal areas: Upper Panhandle (UPH), Lower Panhandle and Guma Lagoon (LPH), Moremi Game Reserve/Xakanaka (MGR), and Chief’s Island (CI). Over 180 morphospecies (approximately 63 families) were recorded during the survey. Multivariate analyses of macroinvertebrate assemblages indicated that assemblages in each of the four focal areas were at least 54% similar at morphospecies level, and 71% similar at family level, although some taxa were more or less common in different areas. Differences in macroinvertebrate assemblages were observed amongst different habitat types, with differences most pronounced between the deltaic habitats and isolated seasonally-flooded pools and temporary rain-filled pools in MGR and CI. The highest number of taxa was recorded in the MGR (125), followed by the UPH (96), CI (93) and the LPH (89) areas. The most families were recorded in the Hemiptera (11), followed by Mollusca (10), Diptera (nine), Coleoptera (nine), Crustacea (six), Ephemeroptera (six) and Odonata (four). Three families of Hirudinea and Trichoptera, and one family of Lepidoptera, were also recorded. Hydracarina were common but not identified beyond order, while Oligochaeta were less frequently recorded. With respect to the different aquatic habitats sampled, the highest number of taxa was recorded in marginal vegetation in the channels and lagoons, although inundated floodplains, floating vegetation and marginal vegetation in backwaters also supported many taxa. The fewest taxa were recorded in sediment. This survey, whilst representing a ‘snapshot’ of the system under low-water conditions, highlights the importance of maintaining a mosaic of aquatic habitats in the Delta. Further studies would enhance our knowledge of the aquatic macroinvertebrate biodiversity of the Okavango Delta, thereby contributing to its conservation. URI: http://hdl.handle.net/10311/869 Files in this item: 1
Dallas_AJAS_2007.pdf (1.160Mb) -
Mosepele, K.; Mosepele, B.; Williams, L. (Botswana Society, NaN, 2005)[more][less]
Abstract: This study investigates the feeding ecology of Schilbe intermedius across its entire life history. Data were collected using experimental fishing nets in two habitats in a seasonal floodplain. The results showed that S. intermedius has an ontogenetic shift in feeding behaviour where the young fish are primarily generalist predators, feeding on aquatic invertebrates while the older fish are more specialised predators feeding primarily on fish. This study showed that there is a higher potential for intra-specific competition among the older fish than in the younger size classes. However, it was recognized that this study is a snap-shot of the feeding ecology of S. intermedius and that a longer time series study is needed to study its feeding ecology. URI: http://hdl.handle.net/10311/940 Files in this item: 1
Mosepele 2005 Prelim.pdf (1.295Mb) -
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) -
Tesfaye, G.; Teketay, D.; Fetene, M.; Beck, E. (Elsevier, www.elsevier.com, NaN, 2010)[more][less]
Abstract: Regeneration of seven indigenous tree species having significant ecological and economic importance was investigated in the Munessa-Shashemene dry Afromontane forest (MSF), southern Ethiopia. Densities and distributions of seedlings, saplings and trees were assessed along gradients of altitude, light and disturbance using quadrat sizes of 10×5 m (for seedlings) and 20×20 m (saplings and trees) following line transects. The number of individuals, frequency and height of the study species were recorded in the quadrats at every 100 m drop in altitude. Seedling densities varied markedly among the species and altitudes. Mean densities (number of individuals ha−1) of seedlings ranged from zero (Polyscias fulva) to 5334 (Prunus africana), and from three (Polyscias fulva) to 102 (Podocarpus falcatus) for trees and saplings. Canonical Correspondence Analysis revealed that seedlings of Celtis africana and Croton macrostachyus were highly favored by disturbance and, hence, were concentrated in canopy gaps within the forest. Based on their population structures, the study species could be categorized into three groups: (1) Species that showed the highest proportion of individuals in the lowest height class and with a gradual decrease towards the upper height classes, which suggests good regeneration; Podocarpus falcatus, C. africana, C. macrostachys and P. africana belonged to this group. (2) Species that showed higher proportions of individuals in the lowest height class and with missing individuals in the subsequent middle height classes, indicative of hampered regeneration; Syzygium guineense and Pouteria adolfi-friederici belonged to this group. (3) Species with no individuals in the lowest and middle height classes but represented by individuals in upper height classes; P. fulva belonged to this group. The species categorized in the last two groups exhibited hampered regeneration, and P. fulva is in the verge of local extermination. High seedling densities (e.g. C. africana and P. africana) and/or adaptive defense mechanisms to herbivory (e.g. P. falcatus and C. macrostachyus) were common attributes of species, which exhibited good regeneration. Regeneration problems were largely attributed to human disturbance, lack of suitable habitat for seed germination or problems associated to seed set (seed predation or abortion). Our study indicated that P. fulva, P. adolfi-friederici and S. guineense require the highest immediate attention for conservation in the MSF. URI: http://hdl.handle.net/10311/827 Files in this item: 1
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Caylor, K.K.; Dowty, P.R.; Shugart, H.H.; Ringrose, S. (November 23, 2011)[more][less]
Abstract: The observed variability in vegetation structure within landscapes was used as the basis for model estimates of the range of annual productivity of landscape patches at four sites along a moisture gradient in southern Africa ranging from 879 to 365 mm mean annual rainfall. Principal components of patch-scale variability in leaf area, woody biomass and vertical leaf profiles were derived from intensive characterization of the small-scale spatial structure of woody vegetation at each site. For each site, the mean and extremes of the principal component distribution parameterized an ecophysiology model of vegetation productivity. Vegetation was most heterogeneous at intermediate locations along the rainfall gradient. Variability in vegetation structure led to a range of annual productivity within one site (600 mm) that accounted for 68% of the total range in mean productivity across all sites. Patch-scale estimates of tree productivity were found to be primarily correlated to annual rainfall (r2=0.66, P=0.001) and not woody leaf area (r2=0.01, P=0.75), while grass productivity was found to be related to values of woody leaf area (r2=0.77, P<0.001) and not annual rainfall (r2=0.11, P=0.29). This result indicates that life-form interactions have a significant role in controlling vegetation productivity across the rainfall gradient. The findings of this study emphasize the importance of considering heterogeneity rather than mean structure when modeling productivity, particularly when considering dynamic vegetation structure, where differences between landscape patches may not be well represented in the mean structure. URI: http://hdl.handle.net/10311/933 Files in this item: 1
Caylor Ringrose 2004.pdf (1.770Mb) -
Thakadu, O.; Irani, T.; Telg, R. (http://www.informaworld.com, April 12, 2011)[more][less]
Abstract: The present study examined the relative effectiveness of 2 public instructional communication methods in improving selected predictors of knowledge-sharing behaviors among communities in the Okavango Delta, Botswana. A total of 120 subjects took part in a quasi experimental study, with 2 experimental treatments: (a) visualized Power Point presentation and (b) verbal presentation with no visual aids. The results showed that neither method was more effective than the other. However, significant differential effects of method by grouping factor, position, were found among belief and intention measures. The study concluded that neither method was more effective, but recommended use of integrated public instructional communication methods. URI: http://hdl.handle.net/10311/778 Files in this item: 1
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Neuenschwander, A.L.; Crawford, M.M.; Ringrose, S. (Taylor & Francis; http://www.tandf.co.uk/journals/titles/01431161.asp, October NaN, 2005)[more][less]
Abstract: The Earth Observing-1 (EO-1) satellite acquired a sequence of data in 2001 and 2002 that highlighted the annual flooding of the lower Okavango Delta. The data were collected as part of the calibration/validation programme for the Advanced Land Imager (ALI) sensor on the NASA EO-1 satellite. The primary purpose of this study was to compare the capability of ALI to that of Landsat ETM+ for large-scale mapping applications in the Okavango Delta. While the extent and inaccessibility of many areas of the Delta make application of remote sensing attractive, the availability of data with adequate spatial and spectral resolution has limited the characterization of the complex patterns of land cover and geomorphology in the Delta. Initial analysis of the ALI data via supervised classification clearly showed macro-flood features, delineation of downstream channel flow areas, and lateral-downstream inundation of the floodplain. These patterns and the proportions of flooding of the channel compared to that of the floodplain (impoundment) varied annually, from the wetter seasonal swamps through the drier seasonal and occasional swamps. Consistently higher classification accuracies achieved using ALI data relative to ETM+ data are attributed to the higher signal-to-noise ratio and the increased dynamic range of the ALI data. URI: http://hdl.handle.net/10311/169 Files in this item: 2
license.txt (1.998Kb)neuenschwander_ringrose_ijrs_2005.pdf (2.296Mb) -
Vanderpost, C.; Ringrose, S.; Matheson, W.; Arntzen, J. (Elsevier, December 14, 2010)[more][less]
Abstract: A methodology was devised for comparison of generalised range condition over time, irrespective of the nature of original imagery used. It was applied for range condition change mapping throughout Botswana through 1984-2000. Results showed that range degradation was most widespread during the 1980s drought when 25% of the country was affected, decreased to 6.5% in 1994 and increased to 9.8% in 2000. This suggests that these semi-arid rangelands are fairly resilient and can withstand “normal” droughts even under conditions of heavy grazing pressure. However, degradation that persists during normal or above average rainfall years is related to increasing livestock and other pressures on rangelands and may represent areas with severe range recovery problems. This application meets some requirements of a semi-arid developing country looking to improve range condition monitoring over relatively remote areas. URI: http://hdl.handle.net/10311/779 Files in this item: 1
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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) -
Moleele, N.M.; Reed, M.S.; Motoma, L.; Seabe, O. (John Wiley and Sons, http://www.wiley.com, NaN, 2005)[more][less]
Abstract: Laboratory-based seed storage systems have been developed as an alternative to in situ conservation for indigenous woody plant species. However, interactions between seed quality and environmental variables must be known for each species prior to seed collection, storage and sowing to ensure effective conservation. This study investigated Acacia tortilis seed weight/quality patterns across seven Botswana seed provenances in relation to: soil nutrient status, altitude; latitude; slope angle; % grass cover; height and density of other woody plants nearby. The higher rainfall and relatively eutrophic seed provenances of northwestern Botswana (Chobe, Okavango and Makgadikgadi) were associated with large A. tortilis species and seeds, as well as higher densities of woody plants. Spatial variation in seed weights of A. tortilis was principally a function of rainfall and soil organic carbon. Although more work is required to establish the relationship between seed weight and germination rates for A. tortilis, this research suggests that seed collection should focus on sites with high levels of rainfall and soil organic carbon. URI: http://hdl.handle.net/10311/947 Files in this item: 1
Moleele African Jour Eco.pdf (705.1Kb) -
Magole, L. (http://www.routledge.com/, NaN, 2009)[more][less]
Abstract: This paper analyses land management policy using land use mapping, interviews with farmers and other stakeholders, and a review of secondary material. The study was carried out in the Lake Ngami area of Ngamiland District in Botswana. It found that the net effect of policy and development initiatives implemented to curb perceived overstocking, overgrazing, open access tenure and low-output subsistence production was to narrow down the livelihood options for the rural poor and cause further damage to the rangeland. Policy-makers ignored the multi-purpose land use systems and goals of traditional pastoral systems, and emphasised commercialisation of livestock farming and privatisation of communal land. This unfortunately weakened or destroyed the local, traditional land management institutions and set in motion the shrinking of the commons. These policies are a colonial legacy that has survived the transitions from colonial rule to independence. URI: http://hdl.handle.net/10311/807 Files in this item: 1
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Mladenov, N.; McKnight, D.M.; Wolski, P.; Murray-Hudson, M. (Elsevier, www.elsevier.com/locate/ecolmodel, NaN, 2007)[more][less]
Abstract: In order to examine dissolved organic matter (DOM) fluxes in seasonal wetland systems that expand and contract seasonally, a time-variable model of dissolved organic carbon (DOC) was developed for a seasonal floodplain in the Okavango Delta of Botswana. The model simulates DOC concentrations from March 2001 to November 2002, during which time DOC concentrations varied between 8 and 31mgCL−1. The model uses a continuously stirred tank reactor (CSTR) approach to describe the hydrologic and biogeochemical controls on DOC leached from litter within the floodplain and transported into the floodplain from upstream. In 2002, a fire burned the floodplain and less litter was available for leaching than in 2001. The model was driven by observations of discharge, water temperature, upstream DOC concentrations, and DOC leaching rates from leaching experiments. Leaching experiments with sedges and grasses indicated that on average 23mgDOCg−1 were leached during the first day ofwetting and 0.6mgDOCg−1 d−1 were continuously leached afterwards. Leaching experiments also showed a decreased amount of DOC released from burned litter and soils than from unburned litter and soils. A two-pool first-order decaymodel that represents both rapidly (0.14 d−1 (at 22 ◦C)) and slowly (0.045 d−1) decaying pools of DOC provided the best representation of observed patterns in DOC concentration in 2001. The decay rate of the first pool decreased by nearly half in 2002, when an estimated 78% of litter was removed by fire. Upstream DOC transport into the floodplain was the dominant source of DOC (representing approximately 70% and 75% of the DOC input in 2001 and 2002, respectively), followed by DOC leaching from litter and DOC originating from microbial sources. In 2001, decomposition (representing approximately 36% of the DOC loss), outflow to an adjacent floodplain (36%) and infiltration (28%) were the major removal mechanisms for DOM from the study floodplain. The large amount of DOC transported by infiltration implies storage of DOC in the subsurface, whichmay influence subsurface heterotrophic activity. In light of future climate change anticipated for the region, a scenario using a 2 ◦C increase in average water temperature and 10% reduction in upstream DOC mass was performed and resulted in significant (11%) reduction in annual DOC mass within the study floodplain. URI: http://hdl.handle.net/10311/497 Files in this item: 1
Mladenov2007Simulation.pdf (2.048Mb) -
Cassidy, L.; Binford, M.; Southworth, J.; Barnes, G. (Taylor & Francis, October 23, 2009)[more][less]
Abstract: The trend of land cover (LC) and land cover change (LCC), both in time and space, was investigated at the Simen Mountains National Park (SMNP), a World Heritage Site located in northern Ethiopia, between 1984 and 2003 using Geographical Information System (GIS) and remote sensing (RS). The objective of the study was to generate spatially and temporally quantified information on land cover dynamics, providing the basis for policy/decision makers and resource managers to facilitate biodiversity conservation, including wild animals. Two satellite images (Landsat TM of 1984 and Landsat ETM+ of 2003) were acquired and supervised classification was used to categorize LC types. Ground Control Points were obtained in field condition for georeferencing and accuracy assessment. The results showed an increase in the areas of pure forest (Erica species dominated) and shrubland but a decrease in the area of agricultural land over the 20 years. The overall accuracy and the Kappa value of classification results were 88 and 85%, respectively. The spatial setting of the LC classes was heterogeneous and resulted from the biophysical nature of SMNP and anthropogenic activities. Further studies are suggested to evaluate the existing LC and LCC in connection with wildlife habitat, conservation and management of SMNP. URI: http://hdl.handle.net/10311/811 Files in this item: 1
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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) -
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) -
Masamba, W.R.L.; Muzila, A. (Botswana Society, NaN, 2005)[more][less]
Abstract: The concentration of the metal ions Na, K, Ca, Mg, Zn, Cu, Mn, Co, Fe, Cr, Ni, and Pb were determined in water samples of the Okavango Delta’s panhandle - Maunachira-Khwai water system during periods of high (June 2004) and low (November 2004) water flow. The concentrations of Na (1.67 to 12.77 mg/L), K (1.37 to 5.80 mg/L), Ca (2.46 to 6.98 mg/L) and Mg (0.69 to 2.83 mg/L) increased with distance from Mohembo indicating concentration of these metal ions by evaporation. Cu (up to 0.028 mg/l), Co (up to 0.053 mg /L), Fe (0.010 to 0.60 mg/L), Ni (up to 0.052mg/L), Mn (up to 0.044 mg/L) and Pb (0.017 to 0.28 mg/L) generally decreased in concentration with increase in distance from Mohembo, indicating that the Delta acts as a filter for these ions. Zn (0.049 to 0.101 mg/L) had lower concentrations at Mohembo than the other sampling sites, indicating solubilisation of previously deposited metals ions, or presence of Zn within the Delta. Chromium was not detected except at Seronga (0.026 mg/L) during periods of high water flow. URI: http://hdl.handle.net/10311/951 Files in this item: 1
Masamba 2005 Spatial.pdf (2.281Mb)