ارزیابی کارشناسان از مفاهیم اعمال شده توسعه پایدار محیط زیست به اکوسیستم های ساحلی

With the broad aim of promoting the essential interdisciplinary research on sustainable development and contributing to the development of an operational bio-economic analysis, the present paper attempts to evaluate four representative approaches to Ecologically Sustainable Development (ESD) in the context of coastal ecosystems. These approaches are non-declining utility per capita, preservation of all the existing natural capital, preservation of the biological crucial levels, and conservation of the critical natural capital. They reflect contemporary dialogue and especially the tension between the schools of strong and weak sustainability. The evaluation was performed by the international community of coastal experts through responses to a questionnaire survey (n = 99). It emerges that those approaches to ESD that integrate operational criteria and principles from natural sciences within the consideration of socioeconomic welfare are evaluated as more functional as well as scientifically more appropriate for defining the target of ESD in coastal ecosystems.

A new field of sustainability science is emerging that seeks to understand how human and natural systems can coexist sustainably. Sustainability science rejects the traditional separation between sciences and calls instead for a ‘synthesis’ of sciences (Carpenter et al., 2009; Cummins and McKenna, 2010; Kates et al., 2001; Palmer et al., 2005; Weinstein et al., 2007). The present paper, inspired by the ideas of sustainability science, is intended as a contribution to interdisciplinary dialogue on Ecologically Sustainable Development (ESD), with particular reference to the case of coastal ecosystems. Two major sciences are involved, ecology and economics. Since the emergence of the issue of ESD, economists and ecologists have both attempted to define it scientifically and operationally. Nevertheless the two disciplines have generally worked in isolation (Ostrom and Cox, 2010). With respect to ESD, Economics examines the conditions under which development can continue indefinitely. This is only to be expected because development is the focus of interest of modern (post-World War II) economists and is considered to be the ‘engine’ of economic process. The international literature on ESD has been influenced by the theories of economic growth resulting in the restriction of the notion of ESD within the boundaries and understanding of economic science (Wai-Yin and Shu-Yun, 2004). Conceptualizing ESD in terms of socioeconomic welfare appears to be attractive to the broader scientific community, politicians, decision makers and society as a whole. Within this framework, competing schools of thought have formed with regard to the operational interpretation of ESD and especially its application to policy making. The prevailing scientific paradigms are those of strong and weak sustainability, which will be discussed below. In contrast, ecological approaches to ESD are defined mainly in terms of ecological criteria with little reference to social and economic needs. In this respect, natural scientists focus on the ecological dimensions of sustainability. Concepts such as ‘ecosystem health’, ‘biological integrity’, ‘carrying capacity’, ‘stability’ and ‘thresholds’ have been used extensively to define the operational content of ecological sustainability (Aarts, 1999; Callicott et al., 1999; Callicott and Mumford, 1997; Chu and Karr, 2001; Ives and Carpenter, 2007; Karr, 1991; Stevenson, 2011, 1997). The concept of planetary boundaries has been proposed which incorporates the role of ‘thresholds in key earth system processes that exist irrespective of peoples’ preferences, values, or compromises based on political and socioeconomic feasibility, such as expectations of technological breakthroughs and fluctuations in economic growth' (Rockstrom et al., 2009). Recent evidence reveals that humans are now forcing a planetary-scale transition with unpredictable consequences for human well-being (Barnosky et al., 2012). The purely ecological considerations of ESD have been appreciated and adopted mainly by natural scientists who possess relevant experience in ecology and biology. Nevertheless, criteria proposed on ecological grounds could be incorporated into socioeconomic approaches as components in a broader platform that aims not only to attain socioeconomic welfare but also to preserve the environmental, social and economic rights of current and future generations. The adoption of those criteria requires appropriate ethical standards in human society and less political resistance (Cairns, 2001). The present essay attempts to contribute to the formation of research directions for defining and operationalizing ESD. Coastal ecosystems with their history of research and planning provide good conditions for an interdisciplinary approach. Recently, coastal ecosystems have been examined extensively in respect of the so-called Ecosystem Based Approach (EBA) and the provision of ecosystem services (Barbier et al., 2008; Enemark, 2005; Granek et al., 2010; Katsanevakis et al., 2011; Luisetti et al., 2011; Nobre, 2009). Long-standing policy making processes in the United States of America (USA) and the European Union (EU) ensure sufficient data on policy design, application and evaluation. The EU's Water Framework Directive and the Clean Water Act in the USA are examples of two advanced and up-to-date policies. In the present study, certain indicative and representative ESD approaches were evaluated by coastal ecosystems experts coming from the natural sciences. This was a two-fold experiment. On the one hand, members of the international community of natural scientists working in coastal and marine ecosystems (marine ecologists, marine biologists and oceanographers) were asked to evaluate one new and three prevailing approaches to ESD in respect of their ability to define appropriate targets for ESD in the specific case of coastal ecosystems, and of their potential to inform policy design and decision making. On the other hand, the results of our survey might provide valuable insights to economists concerning the incorporation of elements from the natural sciences into economic thinking. Recent research conducted in Germany concerned how neoclassical environmental and ecological economists involved in sustainability research think about the issues of sustainability and economics, and how they feel about the current scientific divide between strong and weak sustainability (Illge and Schwarze, 2009). One of the findings of that research is that the representatives of both schools of thought seem to share common concepts of ESD. Our study takes one further step forward by asking natural scientists to participate in the discussion on ESD. Our choice to limit the survey only to natural scientists among all coastal experts coming from various disciplines (economists, engineers, etc.) is inspired by the current call of the emerging field of sustainability science for the incorporation of the knowledge of natural sciences into the decision-making process (Clark and Dickson, 2003). Ultimately, our study facilitates the process of transferring the scientific knowledge of coastal experts to other scientists involved in ESD research. The remainder of the paper is structured as follows. The following section reviews the literature on ESD and Section 3 presents in more detail the four ESD approaches that are evaluated in our international survey. Section 4 describes the survey research and its results, which are discussed in the concluding Section 5.

The socioeconomic welfare of millions of people living in coastal areas is inextricably linked with the ecological condition of coastal ecosystems. Directly or indirectly, coastal ecosystems provide ecological goods and services essential for human survival and well-being. In addition, relevant natural assets contribute as production factors in the production of various goods. In an intergenerational context, it is important to maintain the major ways in which coastal ecosystems contribute to human well-being (e.g. aquatic life and recreation) by protecting certain properties and functions of coastal ecosystems. Thus, defining operational conditions of ESD in coastal ecosystems, among other parameters, necessitates integrating the scientific knowledge of natural sciences into decision making. In this context, the present paper attempts to elicit the scientific knowledge and experience of coastal experts. We conducted an experiment through an international questionnaire survey in order to find out how coastal experts (marine biologists, marine ecologists and oceanographers) rate four representative ESD approaches. These four approaches originate mainly in the socioeconomic sciences and aspire to be policy relevant. The experiment offers interesting results on multiple levels. First, it supplies valuable input to the intensive dialogue concerning the dominant approaches to ESD, which have been proposed mainly by economists and influence decision makers, politicians and citizens. Additional input from experienced natural scientists is essential in order to enrich the scientific investigation of sustainable development. Second, the results contribute to the participation of the natural sciences in the interdisciplinary dialogue through the analysis and operational clarification of the prevailing and representative ESD approaches. The findings of the experiment may feed the dialogue between economists and ecologists–biologists and help to promote the establishment of an essential bio-economic paradigm. In this paper, the term bio-economic paradigm defines a paradigm that essentially integrates elements from the sciences of biology and economics in order to design an operational framework towards ESD. The two disciplines ought to communicate and cooperate through mutual understanding of their respective methodologies, assumptions, constraints and findings. As a result, economists may hesitate to continue to define ESD without clear input from biology and ecology, given that natural scientists possess knowledge of the functioning of ecosystems within which human activities take place. On the other hand, the natural sciences may come to recognize the paramount importance of socioeconomic welfare for the current generation as well as future generations. The survey results confirm a basic assumption of the emerging field of sustainability science, that the concept of ESD requires interdisciplinarity. It appears that coastal experts consider the approaches that incorporate economic and biological criteria (Critical Natural Capital and Biologically Crucial Levels) to be the best suited for (i) defining the concept of ESD and the framework for attaining ESD, and (ii) forming the basis for effective environmental policy design in the coastal ecosystems. These two approaches make use of genuine biological and ecological terms for defining the operational conditions of sustainable development. Although the Biologically Crucial Levels and Critical Natural Capital approaches originate in the economic sciences and are founded on socioeconomic definitions, they adopt ecological criteria for the operational design of sustainable development. The Biologically Crucial Levels approach seems more attractive to coastal experts than the Critical Natural Capital approach in two respects: its scientific consistency and coherence, and the appropriateness of the proposed operational conditions for achieving ESD. This preference is possibly attributable to the two main differences between the Critical Natural Capital and Biologically Crucial Levels approaches. First, within the framework of the Biologically Crucial Levels approach, the crucial functions, species, elements and their corresponding biologically crucial levels are defined with respect to the ecological condition regardless of whether man-made substitutes exist or not. In the Critical Natural Capital approach, the critical natural capital is defined as such as if there are no man-made substitutes. In the intergenerational context, this difference becomes fundamental as future generations may not be satisfied with man-made substitutes, which could reduce their potentials for forming preferences and satisfying needs under the conditions that may arise and prevail in the future. This rationale is very close to the thinking of the vast majority of ecologists and biologists who reject the possibility of substituting important ecological processes and functions with “artificial” substitutes (Ehrlich, 1989). The second difference between the Biologically Crucial Levels and Critical Natural Capital approaches is that the latter defines the criticality of the natural capital based on economic, political and social criteria (MacDonald et al., 1999). In contrast, the Biologically Crucial Levels approach defines biologically crucial levels – the crucial parameters of sustainability – irrespective of socioeconomic criteria, and proposes their preservation regardless of the costs involved. The Per Capita Utility and All Natural Capital approaches do not seem to be appropriate for defining and attaining ESD, according to the coastal experts' evaluation. In particular, the Per Capita Utility approach was regarded as clearly the least appropriate on four of the five dimensions examined within the questionnaire. This result could be expected, because Per Capita Utility does not define any particular environmental objective as long as per capita utility is non-decreasing. This view is contrary to the principles and rationale of the natural sciences. With regard to the All Natural Capital approach which substantially constrains the socioeconomic process, the opinions of the coastal experts are unexpectedly revealing. For each dimension examined, coastal experts evaluated the All Natural Capital approach with intermediate mean scores. To a large extent the All Natural Capital approach reflects deep ecological beliefs. Therefore it seems that coastal experts recognise that the All Natural Capital approach places extreme and infeasible limits on economic processes. Our survey suggests that those approaches that accept the criterion of socioeconomic welfare while clearly proposing the preservation of its biological necessities, are appropriate for describing the operational conditions for achieving ESD and therefore for influencing environmental policy design in coastal ecosystems. These approaches shape an interdisciplinary bio-economic framework for sustainable development. It seems that, scientific research and dialogue over ESD interpretation and application should focus on the improvement and development of bio-economic approaches. These approaches need to widen and enrich their rationale and become more sharply defined. This requires cooperation among the relevant sciences, in at least two respects: (i) the natural sciences should identify the ecological limits and constraints that need to be observed in operational terms; and (ii) economists and decision makers should identify the possibilities for economic development without violating the ecological limits proposed by natural scientists.