As a life-supporting system, marine ecosystem provides various services for human being. Based on ecosystem services, we developed a Benifit and Cost Analysis model to balance the conflicts between economic income and environmental loss caused by mariculture activities. This model not only calculates market income of mariculture but also monetizes the positive and negative effects of mariculture activities on ecosystem services. In this model, three indices, the NPV (Net Present Value), BCR (Benefit to Cost Ratio) and RC (Relative Coefficent) with consideration of discount rate, are developed to assess and prioritize the candidate mariculture modes. This Benefit and Cost Analysis model was applied to Sanggou Bay, one typical mariculture bay in China, to identify sustainable mariculture mode. In this paper, we find that benefit and cost analysis based on ecosystem services value provides a convenient and effective tool to compare different exploitation modes of marine ecosystem.
Ecosystem services and their valuation research have become one of the most important research fields of applied ecology. Research on ecosystem services mainly focuses on the ecological theories, valuation methods, and their applications (Costanza et al., 1997 and Daily, 1997). At the scope of ecological theory, the definition of ecosystem services, given by Daily (1997), was widely used. However, the definition by Millennium Ecosystem Assessment (MA, 2003) was more apt to the sociology and management. Although there is no standard to classify the ecosystem services now, the MA's classification is very useful and practical for valuation (MA, 2003). At the aspect of valuation methods, argues still exist (Farber et al., 2002 and De Groot et al., 2002). Many techniques could be used to assess people's Willingness to Pay (WTP), however, the valuation for the non-market services is still weak. At the fact of applications, more attention is attracted. Most of the research focused on the tradeoff between economic activities and ecosystem services in order to guide the management of the ecosystem in a sustainable way. For example, Folke et al. (1991) argued that with the rapid increase of agriculture, industry and fishing, natural capital has become the major limiting factor for economic development of Balic Sea Region, and ecological engineering and the management for production are important measures to promote the sustainable development of economy. There are also many other relative studies (Alexander et al., 1998, Kreuter et al., 2001 and Schröter et al., 2005).
In China, the concept of ecosystem services was introduced in 1990s, and there have been many studies about ecosystem services which involve the introduction of abroad studies, valuation methods and case studies. At present, the application research of ecosystem services attract more attention. Our study tries to apply benefit and cost analysis to quantify the influence of mariculture on marine ecosystem services, and identify a sustainable mariculture mode by optimizing the ecosystem services value.
Benefit and cost analysis has been promoted as a democracy enhancing technology, and policymakers and consultants have promoted it as a tool for clarifying and rationalizing social choices and building consensus (Chestnut and Mills, 2005). Spurgeo (1998) studied the economic efficiency of coastal habitat rehabilitation and creation through developing a benefit to cost ratio (BCR) model in benefit and cost analysis (BCA). Hansjürgens (2004) discussed the possibilities and limitations of cost–benefit analysis (CBA), and concluded that “CBA is not only a mere mechanism of monetarisation, but a heuristic model for the whole process of valuation”.
In this paper, an improved benefit and cost analysis model based on ecosystem services is developed. This model highlights the selection of decision-making criterion. Firstly, in this paper, the definition of benefit and cost are based on the marine ecosystem services, which take into account most of the benefits and costs (including both economic and ecological contribution and loss) generated by mariculture activities. For example, the increasing food production value indicates economic benefit, and the decrease value of some ecosystem services is at the cost of affecting environment. On the other hand, the decision-making model modified in this paper is different from other studies combining NPV and BCR as one integrated index (RC). The decision-making method used in this model gives a way to balancing benefit and efficiency in resource exploitation and environment protection.
Human well-being and progress toward sustainable development are vitally dependent upon the Earth's ecosystems. Changes in availability of all the ecosystem services can profoundly affect aspects of human well-being (Zheng et al., 2006). Humans are altering the capability of ecosystems to continue to provide many of these services while their demands for ecosystem services are growing rapidly. Management of this relationship is required to enhance the contribution of ecosystems to human well-being without affecting their long-term services-providing capacity (MA, 2003).
