Browsing Okavango Research Institute (ORI) by Title
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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) -
Wondie, M.; Schneider, W.; Melesse, A.; Teketay, D. (MDPI Publishing; www.mdpi.com, January 5, 2011)[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/10311/1001 Files in this item: 1
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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) -
Abiyu, A.; Lemenih, M.; Gratzer, G.; Aerts, R.; Teketay, D.; Glatzel, G. (BioOne, www.bioone.org, May NaN, 2011)[more][less]
Abstract: Exclusion of grazing animals and tree plantations are 2 methods that have been used for restoration of degraded lands in tropical semiarid areas. These 2 options can foster secondary forest succession by improving soil conditions, attracting seed-dispersal agents, and modifying microclimate for understory growth. We compared native woody plant diversity and soil chemical and physical attributes under exclosure and on Eucalyptus globulus (EGP) and Cupressus lusitanica (CLP) plantations. Vegetation data were collected by an inventory of stands with circular plots of 5.64 m radius, and soil samples were collected from the 4 corners and center of 20 × 20 m plots. As a result, 15 native woody plant species belonging to 13 families were recorded. Importance value index (IVI), Shannon-Wiener, Simpson's diversity, and species richness were higher in the exclosure, followed by EGP and CLP. Contents of soil organic carbon and total nitrogen showed significance difference and were highest in the exclosure, followed by CLP, EGP, and grazing land. Although the difference was not significant, an increasing trend was observed for cation exchange capacity and K+. Bulk density was highest on the grazing land, followed by EGP, CLP, and exclosure. Our results suggest that degraded land reclamation can be achieved with plantation of rapidly growing tree species as well as exclosure. However, native woody species diversity and improved soil attributes are better achieved with exclosure. Exclosures can be established interspersed strategically with single- or mixed-species plantations to facilitate restoration of native vegetation. However, it is important to conduct further research on the comparative advantage of enrichment planting of exclosures with preferred tree species or exclosures interspersed within blocks of plantation. URI: http://hdl.handle.net/10311/989 Files in this item: 1
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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) -
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) -
Fynn, R.; Morris, G.; Ward, D.; Kirkman, K. (Wiley Online Library, March 4, 2011)[more][less]
Abstract: Question: Following the framework of Suding et al.(2003), we examined whether morphological traits (organismal response), tolerance and competitive effect (specific process response) were associated with grass dominance (abundance response) on burning, mowing, fertilization and soil depth gradients in KwaZulu-Natal (KZN), South Africa. Location: University of KwaZulu-Natal, Pietermaritzburg, South Africa. Methods: Using several pot experiments involving 29 grass species in total, we determined the vegetative traits, competitive effect and response, and tolerance to shading for grasses common in closed, tufted mesic grassland in KZN. Results: The primary axis of grass–trait variation was most strongly related to a negative correlation (trade-off) between growth rate and specific leaf area (SLA), with broad-leaved, rapidly-growing grasses (high SLA) occupying one extreme and narrow-leaved, slow-growing grasses (low SLA) the other extreme of the first principal component. The low SLA, slow-growth strategy was found to be a relatively general strategy among grasses dominant in undisturbed, high litter grassland, as well as those adapted to moisture-stressed habitats. In contrast, grasses dominant in highly productive habitats with some form of disturbance, e.g. mowing, had a broad-leaved, rapid-growth strategy. Intermediate combinations of the SLA–growth rate trade-off were common among grasses dominant under other combinations of disturbance and soil resource availability. Conclusions: Distinct patterns of organismal (SLA, growth rate) and specific process (competitive effect and response, as well as tolerance of shading) responses appeared to be associated with grasses dominant on gradients of burning, mowing, fertilization and soil depth. These organismal and specific process responses were similar to those for North American and European grasses dominant under the same environmental influences, suggesting that some general trait–environment patterns exist at an inter-continental scale. This general trait–environment relationship appears to be driven by functional adaptive selection along the SLA–environment continuum and its unavoidable trade-off with growth rate. URI: http://hdl.handle.net/10311/810 Files in this item: 1