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The application of choice modelling techniques to guide the management of estuaries in South Africa – case studies at the Sundays, Kromme, Nahoon and Gonubie River estuaries
Expanded Title:Two complementary schools of thought have developed about the management of estuaries in South Africa. One approach advocates Resource Directed Measures (RDM) and has its focus on interventions to secure the minimum natural resource requirements for ecosystem functioning. The other approach advocates an economic approach to allocating and managing ecosystem goods and services. The latter views the generation of credible values for environmental goods as important guides to their social management. The primary aim of this project was to generate information to assist management choices in connection with current demand interest. The selected estuaries were Sundays, Kromme, Nahoon, and Gonubie River estuaries. Focus groups of stakeholders and experts, with interest in and knowledge of selected estuaries were created, and they were tasked to identify and select strategies and investment and operational options on behalf of society - with the goal of improving the recreational appeal of these estuaries. For all the above-mentioned options (specific to each estuary), marginal willingness-to-pay (WTP) values were calculated by applying the Choice Experiment (CE) method. The calculation is made from estimates of choice models. Three different choice model specifications were estimated for these estuaries: a conditional logit (CL) model; a heteroskedastic extreme value (HEV) model, and a random parameters logit (RPL) model. In the case of the Sundays River Estuary, the results from the RPL, HEV and CL models revealed that recreational users were willing to pay more for an estuary management strategy which enabled higher physical size of the fish stock; lowered the amount of boat congestion; and improved the amount of public access available. In the case of the Kromme River Estuary, the results from the RPL, HEV and CL models revealed that recreational users were willing to pay more for an estuary management strategy which enabled higher levels of navigability; reduced the amount of boat congestion; and lowered the amount of access to jet ski and wet bikes. In the case of the Nahoon and Gonubie River Estuaries, the results of the RPL, HEV and CL models revealed that recreational users were willing to pay additional rates for improved water safety, protection from criminal activity and support services. However, tests for multi-collinearity were positive, indicating the possibility that orthogonality of the experimental design was compromised. For this reason, no conclusions for management intervention were drawn on the basis of these results. Demonstration of the application of the method to guide management interventions, was therefore restricted to the examples of the Sundays and the Kromme RIver estuaries. The particular management advice generated and reported above, for the Sundays and the Kromme River Estuaries, cannot be extrapolated to all other estuaries because the situations of each estuary differ.
Date Published:01/12/2012
Document Type:Research Report
Document Subjects:Ecosystem - Biodiversity protection
Document Format:Report
Document File Type:pdf
Research Report Type:Standard
WRC Report No:1924/1/12
ISBN No:978-1 4312-0359-8
Authors:Hosking SG
Project No:K5/1924
Originator:WRC
Organizations:Departments of Economics, Nelson Mandela Metropolitan University
Document Size:2 592 KB
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