Browsing by Author "Nkambule, Nonophile"

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    Clearing invasive alien plants as a cost-effective strategy for water catchment management : the case of the Olifants river catchment, South Africa
    (AOSIS Publishing, 2016) Morokong, Tshepo; Blignaut, James; Nkambule, Nonophile; Mudhavanhu, Shepherd; Vundla, Thulile
    Invasive alien plants have a negative impact on ecosystem goods and services derived from ecosystems. Consequently, the aggressive spread of invasive alien plants (IAPs) in the river catchments of South Africa is a major threat to, inter alia, water security. The Olifants River catchment is one such a catchment that is under pressure because of the high demand for water from mainly industrial sources and unsustainable land-use, which includes IAPs. This study considered the cost-effectiveness of clearing IAPs and compared these with the cost of a recently constructed dam. The methods used for data collection were semistructured interviews, site observation, desktop data analysis, and a literature review to assess the impact of IAPs on the catchment’s water supply. The outcomes of this study indicate that clearing invasive alien plants is a cost-effective intervention with a Unit Reference Value (URV) of R1.44/m3, which compares very favourably with that of the De Hoop dam, the URV for which is R2.93/m3. These results suggest that clearing invasive alien plants is a cost-effective way of catchment management, as the opportunity cost of not doing so (forfeiting water to the value of R2.93/m3) is higher than that of protecting the investment in the dam.
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    A cost-benefit analysis of using Rooikrans as biomass feedstock for electricity generation : a case study of the De Hoop nature reserve, South Africa
    (AOSIS Publishing, 2016) Mudavanhu, Shepherd; Blignaut, James; Nkambule, Nonophile; Morokong, Tshepo; Vundla, Thulile
    Invasive alien plants (IAPs) like Rooikrans (Acacia Cyclops) have several undesirable effects on both the natural environment and the social, economic and cultural wellness of society in the De Hoop nature reserve of the Western Cape Province. A few of these negative effects are: the change in coastal sediment dynamics, the change in seed dispersal dynamics, and the fact that it is overtaking native plants. However, Rooikrans can also potentially be used as biomass feedstock for electricity generation. Following a system dynamics modelling approach, the feasibility of using woody biomass from Rooikrans was investigated. The RE-model used data obtained from the Department of Environmental Affairs’ (DEA) Natural Resource Management (NRM) division, consulted with experts and conducted literature reviews with respect to the subject matter. Three scenarios were tested and the RE-model results showed that all scenarios have a positive cumulative Net Present Values (NPVs), with the exception of the baseline case scenario. This study shows that the production of electricity using Rooikrans woody biomass is a viable and feasible option in comparison with electricity production by diesel generators.
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    The opportunity cost of not utilising the woody invasive alien plant species in the Kouga, Krom and Baviaans catchments in South Africa
    (AOSIS Publishing, 2016) Vundla, Thulile; Blignaut, James; Nkambule, Nonophile; Morokong, Tshepo; Mudavanhu, Shepherd
    This study estimates the opportunity costs of using woody invasive alien plants (IAPs) for value-added products by estimating the net economic return from the value-added industries in South Africa. By 2008, IAPs were estimated at the national level to cover an area of 1 813 million condensed hectares in South Africa. A market has formed around their use for value-added products (VAP) like charcoal, firewood and timber in the Kouga, Kromme and Baviaans River catchments in the Eastern Cape province of South Africa. The net economic return from these value-added industries was estimated for the purpose of several management scenarios, and was then used to estimate the opportunity costs if they were not used. A system dynamics model was used to value and analyse the Net Present Value of clearing in the study area and to estimate the opportunity cost of the non-use of VAP. The study showed that the inclusion of VAPs in the project would yield higher net present values for clearing. The findings from this study suggest that a cofinance option of the total economic returns from VAP for clearing costs is the best management scenario for reducing the costs of clearing and maximising the net economic returns from clearing. The net economic returns of VAPs by 2030 are estimated at R23 million without the co-finance option and R26 million with the option. The cumulative net income from VAPs with co-financing over the period of valuation is estimated to be R609 million.