Analysis of soil organic carbon and vegetation cover trends along the Botswana Kalahari Transect

Ringrose, Susan; Matheson, Wilma; Vanderpost, Cornelis

doi:10.1006/jare.1997.0344

Cited by 56 publications

(53 citation statements)

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“…• the presence of plants (Acacia spp., other legumes and grasses) (Ringrose et al, 1998) or fauna (e.g. termites) symbiotic with nitrogen fixers (Barnes et al, 1992); • very low recharge rates, usually less than 5 mm/a (e.g.…”

Section: The Kalahari Settingmentioning

confidence: 99%

Identification of sources and infiltration regimes of nitrate in the semi-arid Kalahari: Regional differences and implications for groundwater management

Stadler¹,

Talma²,

Tredoux³

et al. 2012

WSA

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The Kalahari region of southern Africa offers much potential for nitrogen input into its groundwater. High nitrate concentrations in Kalahari groundwater are therefore quite common and are caused by both anthropogenic and natural sources. Forecasting groundwater nitrate concentrations remains challenging. Source identification of nitrate contamination in groundwater is an important first step for groundwater management and quality prediction, and is aided by isotope analysis of nitrate in the water. Comparative data from 3 groundwater study sites in the Kalahari of Botswana and Namibia with widely different characteristics are presented. Two of the sites (Ghanzi and Gobabis) have shallow water tables in fractured quartzite. These aquifers were affected by pollution from cattle wastes (manure) and septic tank outflows resulting in groundwater nitrate levels exceeding 1 000 mg NO 3 /ℓ and in δ 15 N values of between +7 and +20 ‰ AIR. Short-term increases of groundwater nitrate concentrations were triggered by exceptional rainfall events occurring every 10-20 years. At the third site (Serowe in Botswana) there is similar land use and land cover, yet the aquifers are deeper, groundwater dates to Late-Pleistocene age and borehole levels do not show a response to present-day high-rainfall episodes. Nitrate levels up to 219 mg/ℓ are found, but lower 15 N content (δ 15 N of +3 to +8 ‰) indicates a natural origin of the nitrate. In this area pollution nitrate is sufficiently delayed in the vadose zone, reaching the saturated zone much later. The data from all 3 sites suggest that nitrogen management options can only be evaluated once an understanding of sources, processes and flow patterns has been established.

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Section: The Kalahari Settingmentioning

confidence: 99%

Identification of sources and infiltration regimes of nitrate in the semi-arid Kalahari: Regional differences and implications for groundwater management

Stadler¹,

Talma²,

Tredoux³

et al. 2012

WSA

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“…For 1000 km, from Zambia through Botswana, the Kalahari Transect ( Fig. 1) follows a rainfall/temperature gradient, along which the vegetation produces several distinct associations under different regimes of precipitation, soil particle size, and depth of sand substrate (Cole & Brown 1976;Skarpe, 1986;Tainton and Walker, 1993;Ringrose et al, 1998). The region offers the opportunity to isolate climatic effects because a near homogeneous layer of Kalahari sand covers 80% of the Botswana surface area and extends well beyond the country's borders ( Jones, 1982;Thomas & Shaw, 1990).…”

Section: Introductionmentioning

confidence: 99%

Carbon and nitrogen in the soil–plant system along rainfall and land-use gradients in southern Africa

Feral

Epstein

Otter

et al. 2003

Journal of Arid Environments

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“…Savanna ecosystems are undergoing rapid changes in composition and structure driven by natural and anthropogenic causes [6]. These changes hold the potential to greatly influence socio-ecological functioning within savanna systems [6][7][8]. African savannas in particular are projected to be under risk of extensive change largely due to changes in climate patterns [9], which may exacerbate the challenges presently facing humans living in this region.…”

Section: Introductionmentioning

confidence: 99%

Application of Object Based Classification and High Resolution Satellite Imagery for Savanna Ecosystem Analysis

et al. 2010

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Savanna ecosystems are an important component of dryland regions and yet are exceedingly difficult to study using satellite imagery. Savannas are composed are varying amounts of trees, shrubs and grasses and typically traditional classification schemes or vegetation indices cannot differentiate across class type. This research utilizes object based classification (OBC) for a region in Namibia, using IKONOS imagery, to help differentiate tree canopies and therefore woodland savanna, from shrub or grasslands. The methodology involved the identification and isolation of tree canopies within the imagery and the creation of tree polygon layers had an overall accuracy of 84%. In addition, the results were scaled up to a corresponding Landsat image of the same region, and the OBC results compared to corresponding pixel values of NDVI. The results were not compelling, indicating once more the problems of these traditional image analysis techniques for savanna ecosystems. Overall, the use of the OBC holds great promise for this ecosystem and could be utilized more frequently in studies of vegetation structure.

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Analysis of soil organic carbon and vegetation cover trends along the Botswana Kalahari Transect

Cited by 56 publications

References 0 publications

Identification of sources and infiltration regimes of nitrate in the semi-arid Kalahari: Regional differences and implications for groundwater management

Identification of sources and infiltration regimes of nitrate in the semi-arid Kalahari: Regional differences and implications for groundwater management

Carbon and nitrogen in the soil–plant system along rainfall and land-use gradients in southern Africa

Application of Object Based Classification and High Resolution Satellite Imagery for Savanna Ecosystem Analysis

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