Northeastern Namibia Research Articles

Global neoproterozoic petroleum systems: The emerging potential in North Africa, by Jonathan Craig, J. Thurow, B. Thusu, A. Whitham, and Y. Abutarruma. Geological society special publication, 326, 2009. No. of pages: 309. ISBN 978‐1‐86239‐287‐8 (hardback).

Global neoproterozoic petroleum systems: The emerging potential in North Africa, by Jonathan Craig, J. Thurow, B. Thusu, A. Whitham, and Y. Abutarruma. Geological society special publication, 326, 2009. No. of pages: 309. ISBN 978‐1‐86239‐287‐8 (hardback).

Model and experiences of initiating collaboration with traditional healers in validation of ethnomedicines for HIV/AIDS in Namibia

Many people with Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome (HIV/AIDS) in Namibia have access to antiretroviral drugs but some still use traditional medicines to treat opportunistic infections and offset side-effects from antiretroviral medication. Namibia has a rich biodiversity of indigenous plants that could contain novel anti-HIV agents. However, such medicinal plants have not been identified and properly documented. Various ethnomedicines used to treat HIV/AIDS opportunistic infections have not been scientifically validated for safety and efficacy. These limitations are mostly attributable to the lack of collaboration between biomedical scientists and traditional healers. This paper presents a five-step contextual model for initiating collaboration with Namibian traditional healers in order that candidate plants that may contain novel anti-HIV agents are identified, and traditional medicines used to treat HIV/AIDS opportunistic infections are subjected to scientific validation. The model includes key structures and processes used to initiate collaboration with traditional healers in Namibia; namely, the National Biosciences Forum, a steering committee with the University of Namibia (UNAM) as the focal point, a study tour to Zambia and South Africa where other collaborative frameworks were examined, commemorations of the African Traditional Medicine Day (ATMD), and consultations with stakeholders in north-eastern Namibia. Experiences from these structures and processes are discussed. All traditional healers in north-eastern Namibia were willing to collaborate with UNAM in order that their traditional medicines could be subjected to scientific validation. The current study provides a framework for future collaboration with traditional healers and the selection of candidate anti-HIV medicinal plants and ethnomedicines for scientific testing in Namibia.

Rare earth and trace element geochemistry of termite mounds in central and northeastern Namibia: Mechanisms for micro-nutrient accumulation

Rare earth element (REE) and trace element concentrations of ten termite mounds and adjacent topsoil from central and northeastern Namibia were used to investigate the processes underlying the alteration of soil chemical and physical properties by termites ( Macrotermes spp.). Accumulation of micro-nutrients in the mounds was of particular interest because of the ecological implications of the enhanced availability of these scarce elements. The absolute concentrations of REE and trace elements, including nine micro-nutrients (B, Fe, Mn, Ni, Cu, Zn, Se, Mo and Cd), were greater in termite mounds compared to topsoil, suggesting a possible external supply of enriched materials or accumulation of in situ weathering products of the underlying bedrock. Similarities between the chondrite normalized REE patterns of the samples and those of the average upper continental crust (UCC) and Post-Archaean Average Australian Shale compositions indicated that the mounds and topsoil at each site originated from the same host bedrock. Coherent behavior between two incompatible elements (Th and La) in both topsoil and mound samples suggested that the two sets of samples were exposed to two different weathering processes. The relatively low Zr/Sc ratios, fine particle sizes and the persistence of positive Eu anomalies of the mounds relative to UCC were interpreted as reflecting (1) a lack of grain sorting effects and (2) active transport of materials rich in primary clay minerals and trace elements from the deeper regolith to the surface by termites. Lower permeability of mound materials may also prevent leaching of primary minerals and trace elements. Titanium and Zr enrichment in most mound samples (8 samples) was attributed to the decomposition of biotite by Macrotermes with the concomitant release of Ti and Zr into the mounds, suggesting the termites' ability to transform soil minerals and enhance chemical weathering. This was further corroborated by a substantial increase in Th/U ratios in most mounds relative to topsoil. Because of the oxidizing conditions of the mounds, Ti and Zr are likely to be adsorbed onto Fe-oxides. Positive Ce anomalies relative to UCC and the high pH values in the mounds indicate calcrete aggradation or mound aeration as a result of burrowing activities of the termites and evaporation from mounds. The impacts of the changes in environmental conditions and the termite activities on the mound geochemistry are highlighted by heavy REE (HREE) as well as Fe and Mn retentions in the mounds. Heavy REE and light REE (LREE) are likely to coprecipitate with carbonate complexes and Fe- and Mn-oxyhydroxides, and in the process, scavenge a series of micro-nutrients such as Zn, Cu, Cd and Co. A substantial enrichment of Se in mounds, despite the oxidizing conditions of the mounds, could be attributed to active transport of Se-enriched materials from deep soil horizons. The study demonstrated the suitability of REE and trace element geochemistry for assessing the influence of Macrotermes on the physico-chemical properties of semi-arid soils.

Beware the Elephant in the Bush: myths, memory and indigenous traditional knowledge in north-eastern Namibia

This article draws on a case study exploring the value of elephant wisdom and myths in managing human-elephant conflict in Caprivi (Namibia). It does so to highlight that Indigenous Traditional Knowledge (ITK) is more flexible than recent concerns suggest. This is because ITK transforms in response to changes in both the biophysical and wider socio-political setting of people's environment. The article demonstrates the transformative nature of ITK by applying the findings of the case study to the literature associated with myths, truth claims and collective memory to argue that ITK has a strong social and cultural element. As such, ITK can be viewed as cultural knowledge which is essential to people's adaptation to their social and biophysical environment. Therefore, ITK will evolve to combine traditional forms of knowledge with new knowledge as the needs of society change, whether this is due to changes in the biophysical, socio-political or both environments. This finding provides valuable insight into the dynamic nature of ITK; it also offers new perspectives on culture and cultural memory in making sense of the world.

The Impact of Nile Crocodiles on Rural Livelihoods in Northeastern Namibia

Nile crocodiles (Crocodylus niloticus) are one of the few dangerous predators regularly found outside protected wildlife areas. This is particularly so in northeastern Namibia where an extensive network of rivers and wetlands coupled with successful conservation measures has allowed crocodile populations to flourish since uncontrolled exploitation ended over three decades ago. This area is predominantly communal land characterized by numerous subsistence communities dependent on river and wetland resources. In recent years, the combination of a growing human population and resurgent crocodile populations has resulted in considerable conflict between humans and crocodiles. The principle objective of this study was to quantify the impact of crocodiles on rural livelihoods. Data were obtained from existing records and through community surveys on the lower Kavango, Chobe and Kwando rivers and upper Zambezi River. Existing estimates suggest an annual loss of ∼255 domestic cattle per year for northeastern Namibia whilst community survey estimates suggest a substantially greater annual loss of ∼6864 cattle per year. Community surveys also revealed conflict between crocodiles and artisinal fishermen, with an estimated 71 500 fishing nets damaged by crocodiles per year. Human-crocodile conflict in Namibia may have greater impacts than previously assumed, and may undermine conservation and development objectives.

Using high-resolution satellite imagery and double sampling as a cost-effective means of collecting forest inventory data – the case of Hans Kanyinga Community Forest, Namibia

The present study deals with the use of high-resolution satellite imagery in forest inventory of the open savanna woodlands of southern Africa. The study was carried out in Hans Kanyinga Community Forest, north-eastern Namibia. A two-phase (double) sampling design was used to estimate the variables of interest, namely stand volume, stand density and diameter distribution. QuickBird satellite images were used to extract auxiliary variables (image data), such as photogrammetric crown diameter and number of stems, using visual interpretation and measuring tools offered by Erdas 8.7 geographic imaging software. Field inventory data (terrestric data) collected in 2002 were used to obtain the terrestric data. Stepwise regression and correlation analysis between satellite imagery and field data was carried out and the results were moderate. The stand volume model explained 56%, the stand density model 81% and the diameter distribution model 43% of the variation. Cost-efficiency assessment of double sampling with regression estimators showed a considerable reduction in inventory costs by up to 24% compared to a traditional forest inventory method in Hans Kanyinga Community Forest. Double sampling was found to be cost-efficient when the proportion of variability of the models was higher than 27%. The inventory concept showed potential in providing information required both at the higher and lower levels of forest management. Follow up research is required.

Mitigating an elephantine epidemic: gendered space for HIV/AIDS outreach through Namibian conservancies

As the reach of HIV/AIDS continues to devastate communities and create potential pressures on natural resources, conservation organizations have increasingly become involved in education and outreach to address the disease. This paper’s purpose is to investigate how increasing HIV infection rates and AIDS deaths relate to community-based conservation and livelihood strategies in the Caprivi Region of northeastern Namibia, and demonstrate that conservation organizations can play a unique role in combating the disease. As the epidemic is more widespread in the Caprivi than in any other region of the country, local organizations such as Integrated Rural Development and Nature Conservation (IRDNC) are responding to the disease by integrating it into conservation work. IRDNC’s efforts reflect a particular focus on gender, including changes in the way that HIV/AIDS is discussed in local communities, strategies to promote access to testing and care, and bringing to light the experiences of individuals and families struggling with HIV/AIDS. This approach shows that there are benefits to be gained from approaching HIV/AIDS mitigation through familiar, existing structures such as those of community conservancies in Namibia—especially the ability to circumvent heavy local stigma. Using data collected through participant observation and participatory discussions, this paper demonstrates that conservation programs can positively affect people with HIV/AIDS, highlighting the importance of mainstreaming outreach efforts that address the particular localized manifestations of the disease in the context of natural resource management.

Groundwater Recharge Assessment for the Kalahari Catchment of North-eastern Namibia and North-western Botswana with a Regional-scale Water Balance Model

Groundwater is the only source of drinking water for the inhabitants of the Kalahari. Thus understanding spatial and temporal variations in groundwater recharge is very important and a regional-scale water balance model has therefore been set up for a 209,149 km2 catchment in north-eastern Namibia and north-western Botswana. The model has a spatial resolution of 1.5 × 1.5 km, daily model time-steps, and climatic input parameters for 19 years are used. The distributed, GIS-based, process-oriented, physical water balance model (MODBIL) used in this study considers the major water balance components: precipitation, evapotranspiration, groundwater recharge, and surface runoff/interflow. Mean precipitation for the study area is 409 mm a−1, while mean actual evapotranspiration is 402 mm a−1 and mean groundwater recharge is 8 mm a−1 (2% of mean annual precipitation). The recharge pattern is mainly influenced by the distribution of soil and vegetation units. Groundwater recharge shows a high inter- and intra-annual variability, but not only the sum of annual precipitation is important for the development of groundwater recharge; a large amount of precipitation in a relatively short period is more important. Published independent data from the Kalahari in Namibia, Botswana and the Southern African region under similar climatic conditions are used to verify the modelling results.

Radiocarbon dating of a very large African baobab

In late 2004, Grootboom, probably the largest known African baobab (Adansonia digitata L.), collapsed unexpectedly in northeastern Namibia. Ten wood samples collected from different areas of the trunk were processed and investigated by accelerator mass spectrometry radiocarbon dating. The radiocarbon dates of three samples were greater than 1000 years BP (radiocarbon years before present, i.e., before AD 1950). The corresponding calibrated calendar age of the oldest sample was 1275 +/- 50 years, making Grootboom the oldest known angiosperm tree with reliable dating results. Variations in radiocarbon dates among the wood samples indicated that, morphologically, Grootboom was a quintuple tree, whereas genetically, it was a single individual. Ages of extreme lateral samples revealed that, over the past 500-600 years, Grootbooom had almost ceased growing, providing information about climate changes in central southern Africa. The sudden demise of Grootboom coincided with the spread of the poorly studied baobab disease, which has become epidemic in Namibia.

Lithostratigraphy of the Kalahari Group in northeastern Namibia

The Kalahari Group in northeastern Namibia consists of terrestrial sediments deposited in a tectonically active basin that was formed by flexural uplift of the African continental margin and independent structures related to rifting. The thickness of the sequence varies from a few meters to around 400 m. Greatest thicknesses occur where the NW–SE trending Kalahari basin axis conjugates with NE–SW trending grabens. Repeated phases of flooding and desiccation dominate the depositional environments of the Kalahari Group in northeastern Namibia. Associations of lithofacies allow recognition of distinct depositional settings such as proximal debris flows, braided streams and sand fans, and pans and sandflats. The northeastern Namibian Kalahari Group rests unconformable on the pre-Kalahari surface which showed a relatively pronounced relief in the Epukiro area. The succession starts with conglomerates, breccias and pebbly sandstones, followed by carbonates, sandstones of various maturities, and silcretes. Ferruginous sandstones and ferricretes occur locally. The onset of Kalahari Group deposition was likely a basin-wide event and therefore the basal lithostratigraphic units can be correlated with confidence. Conversely, the correlation of the succeeding lithostratigraphic units remains fairly speculative.

Effects of anthropogenic fire history on savanna vegetation in northeastern Namibia

Anthropogenic fires in Africa are an ancient form of environmental disturbance, which probably have shaped the savanna vegetation more than any other human induced disturbance. Despite anthropogenic fires having played a significant role in savanna management by herders, previous ecological research did not incorporate the traditional knowledge of anthropogenic fire history. This paper integrates ecological data and anthropogenic fire history, as reconstructed by herders, to assess landscape and regional level vegetation change in northeastern Namibia. We investigated effects of fire frequency (i.e. <5, 5–10 and >10 years) to understand changes in vegetation cover, life form species richness and savanna conditions (defined as a ratio of shrub cover to herbaceous cover). Additionally, we analysed trends in the vegetation variables between different fire histories at the landscape and regional scales. Shrub cover was negatively correlated to herbaceous cover and herbaceous species richness. The findings showed that bush cover homogenisation at landscape and regional scales may suggest that the problem of bush encroachment was widespread. Frequent fires reduced shrub cover temporarily and promoted herbaceous cover. The effects on tree cover were less dramatic. The response to fire history was scale-independent for shrub, herbaceous and tree cover, but scale-dependent for the richness of grass and tree life forms. Fire history, and not grazing pressure, improved savanna conditions. The findings emphasise the need to assess effects of anthropogenic fires on vegetation change before introducing new fire management policies in savanna ecosystems of northeastern Namibia.

Application of a 'stem number guide curve' for sustainable harvest control in the dry woodland savanna of northern Namibia

The savanna woodlands of north-eastern Namibia are a significant source of essential resources for the rural population. Thus far, however, there is little or no growth data available to predict future timber supplies and current yield regulation is limited to the issuing of harvesting permits based on the assessment of available tree sizes, rather than a tree population as a whole. This paper presents the negative exponential function for the development of a guide curve. The curve defines an optimum stand structure based on desired timber yields for specific tree sizes, the intrinsic mortality rates of individual species and the total desirable stocking of a stand. The application of the approach is assessed using the size class distributions of two prominent tree species of the Kanovlei area in north-eastern Namibia. While the function models the development of the populations of the species well, timber and non-timber trees will need to be modelled separately. In the coming years it will be an important priority to establish a system of sample plots to obtain growth data that may support or augment the system. Keywords : Savanna woodlands, stem number, negative exponential function, guide curve Southern African Forestry Journal No. 204 2005: 37-44

The effects of communal land resource management on forest conservation in northern and north-eastern Namibia

The area under natural forests has diminished steadily while deforestation has escalated progressively in the past 10 years. Strategic constraints leading to this ever-increasing rate of forest depletion are examined, and relevant policy interventions for overturning them are suggested. Communal ownership and management of natural resources in the northern and north-eastern Namibia are identified as a major underlying constraint on natural resource conservation because the communal system lacks mechanisms for regulating access. Nonetheless, the study acknowledges the optimistic views on communal use and management in other parts of the world. The assumptions about community, the willingness of its members to realise joint environmental or social goals, and their motivation and skills for natural resource management have been challenged. The perception that communities are custodial and non-materialistic in their attitudes to natural resources is rejected. It is concluded that common resources should be brought under more formal management. There should be a state-community/private partnership, with the state performing an advisory function, and implementation at the highest level through the use of state institutions for law enforcement, while the community or the private interest undertakes day-to-day management and law enforcement activities. Maintaining state ownership of natural resources in communal areas and inviting local people to manage them on their own, or mainly on government terms, is not a solution to natural resource degradation.

The Least Sexist Society? Perspectives on Gender, Change and Violence among southern African San*

This article refutes essentialist popular and academic discourses revolving around the presumption of primordial gender equality and harmony among the San of southern Africa. These discourses continue to ignore the devastating gendered consequences of land and cultural dispossession, poverty and the large-scale militarisation of the San. The discussion focuses on contemporary gender-based violence among San communities against the background of those socio-economic, political and cultural influences that have fundamentally altered gender relations among southern African San. The central argument presented is that, relatively recently, and as a result of specific social and historical circumstances, distinct and hierarchically organised perceptions of 'men' and 'women' have begun to establish themselves to varying degrees among southern African San communities. It is argued that violence between San men and women has been reproduced and exacerbated by the San people's re-appropriation of gender as a significant social category, which is, however, highly ambiguous and contradictory. The comparative analysis employed in this paper draws on recent field research among three major communities of San, at Schmidts-drift in the Northern Cape (South Africa), Ghanzi district in western Botswana, and Tsumkwe West, the area formerly known as 'Western Bushmanland', in north-eastern Namibia. In conclusion, the paper takes up again the cultural discourse of 'traditional' gender equality and harmony, and asks how this, within the wider context of contemporary cultural reclamation, may become a strategic, although contested, tool to address contemporary gender concerns among San people.

Categorizing the Ju|'hoan Musical Heritage

The article presents an illustration of a reflexion on musical categorization, as applied to the Ju|'hoansi settled in North-Eastern Namibia. Their musical heritage can be divided into categories based on the identification and the opposition of musical features, which are culturally relevant. The article also deals with the relations between musical categories, social context and verbalisation as well as with the question of the invariants and the transformations within the system.

Ethnohistory and Archaeology of the Ju/'hoansi Bushmen

The 'Great Kalahari Debate' which revolved around the degree of isolation of the Ju/'hoansi Bushmen failed to adequately interrogate the Bushmen on what they knew of their own history. A combination of interviews with respected Ju/'hoansi elders and archaeological excavation indicates that those Bushmen living in the Sandveld of north-eastern Namibia, although in contact with Kavango farmers, would use them as a convenient source of hxaro exchange items only when needed. This meant only a limited number of exotic pieces were found in the excavations at the hxaro exchange place of Cho/ana in the Kaudom Reserve, suggesting that the Bushmen retained their independence. By way of contrast, hunters living in small rock shelters on the edge of Tswana settlements around Gaberone in Botswana gradually saw their cultural material being completely replaced by exotic goods and food, indicating encapsulation by the dominant society.

Oxpeckers in north-eastern Namibia: recent population trends and the possible negative impacts of drought and fire

Both redbilled oxpeckers ( Buphagus erythrorhynchus) and yellowbilled oxpeckers ( Buphagus africanus) have experienced recent population decreases in southern Africa largely as a result of cattle dipping against ticks, their primary source of food. In Namibia, oxpeckers are confined largely to the Caprivi region in the north-east and the yellowbilled oxpecker is classified as a Namibian Red Data species. Counts in 1983–1984 estimated populations of 2285–3780 redbilled oxpeckers and 2062–2613 yellowbilled oxpeckers on cattle in East Caprivi. In this study, three counts of oxpeckers were made in 1997–1998. Bird numbers had not increased in proportion with cattle numbers, the primary host which had increased three-fold in the last 15 years. Current redbilled oxpecker numbers (3627–4902) were similar to those in the 1980s. Too few yellowbilled oxpeckers were observed to derive robust population estimates, but our counts suggest a decline to about 330 birds. There have been no official cattle dipping programmes in Caprivi, and private tick control is virtually non-existent. We suggest that the current dry conditions, in combination with the increasingly widespread and more frequent practice of veld burning are having a substantial, differential effect on some of the tick species favoured by the two species of oxpeckers. We hypothesise that these two factors act as a control mechanism on ticks favoured by yellowbilled oxpeckers, so precipitating the dramatic decline of this species. If current trends continue, yellowbilled oxpecker will soon disappear from Caprivi.

A review of the African Elapsoidea semiannulata complex (Serpentes: Elapidae)

The status of the three subspecies of Elapsoidea semiannulata is reviewed on the basis of additional material. Typical E. s. semiannulata is extensively parapatric with both E. S. boulengeri and E. sundevallii fitzsimonsi in northeastern Namibia, with no sign of intergradation, so E. boulengeri is reinstated as a full species. Elapsoidea semiannulata moebiusi is retained as a west African subspecies with ventral counts usually above 150. whereas the typical form has counts below 150.

Improved mapping of schooling fish near the surface: comparison of abundance estimates obtained by sonar and echo integration

A method is described for recording fish schools near the surface by means of a computerized sonar system, a conventional echo integration unit, and sampling by a near-surface trawl. The sonar system consists of a 95 kHz SIMRAD SA950 multibeam sonar connected to a work station with software for automatic detection and measurement of schools, and logging of the sonar data. The technique for near-surface trawling is based on re-rigging a pelagic trawl by extending the upper bridles, removing the weights, and attaching two large buoys to each wing. Pelagic fish stocks were mapped in the north-eastern Atlantic and oV Namibia. The abundance estimates obtained by the near-surface recording method were compared with that obtained by conventional echo integration alone for four diVerent surveys. It is concluded that the near-surface recording method can provide more precise mapping and abundance estimates of pelagic fish stocks in schools near the surface. ? 1996 International Council for the Exploration of the Sea

Climatic and edaphic conditions ateragrostis lehmanniananees sites in Arizona, USA and the cape province, RSA and potential seeding sites in Southern Africa

Climatic and edaphic conditions at Eragrostis lehmanniana Nees sites in southeastern Arizona, USA were compared with those in the Cape Province, RSA to determine a range of conditions under which the species might be expected to establish and persist in southern Africa. Mean annual precipitation amounts and temperature extremes were highly variable where Lehmann lovegrass predominates, but in most summers precipitation accumulations ranged from 150–220 mm and temperature extremes ranged from 20–35°C in 30–40 days. Soils at Lehmann lovegrass sites in the Cape Province were more coarse textured and nutrient concentrations were usually less than at sites in southeastern Arizona; but trends in particle‐size distributions and measured chemical concentrations were generally equivalent. Climatic and edaphic conditions in central Botswana and northeastern Namibia generally range between those in southeastern Arizona and the Cape Province, RSA and we expect that seeded Lehmann lovegrass stands in these areas would enhance semi‐desert grassland productivity.