The environmental decision problems often are divisive, even in a technical realm, decision makers with strong personalities influence outcomes. The purpose of this study is to define and quantify the factors that affect the conservation objectives of a national natural park located in Colombia, South America adding the judgments of six decision makers with different knowledge (every decision maker is also a stakeholder representative). This paper uses a hybrid multiple criteria group decision making model (MCDM), combining the social network analysis (SNA), analytic hierarchy process (AHP) and similarity measures to solve the consensus and anchoring problem among environmental decision makers. The SNA technique is used to build an influential network relation map among decision makers and to obtain their weights for applying a weighted analytic hierarchy process. Then, the final decision matrices for every decision maker are compared between them in order to identify the consensus level of the problem.Keywords: Group decision-making; stakeholder analysis; consensus; MCDM; AHP; SNA 1991 Mathematics Subject Classification: 22E46, 53C35, 57S20
IntroductionShared responsibility for the protection of nature demands common solutions to existing problems. Environmental management decisions have been the cause of many debates and deep disagreements underlying the multifaceted nature of most environmental problems. Environmental management takes place at many levels (local communities, city, state) and involves a large number of stakeholders (such as landowners, entrepreneurs, urban planners, farmers...) with conflicting interests 1 . The complexity of environmental problems requires transparent and flexible decision-making processes that integrate different areas of knowledge and values 2 . Therefore, we can affirm that environmental planning is a multi-criteria and multi-stakeholder problem by nature 3 4 . . From all of them, the AHP method proposed by 10 has been chosen because it provides an easy-to-understand framework for decision-making or evaluation problems and also it presents its strengths when working in scenarios with scarce information. AHP * For the title, try not to use more than three lines. Typeset the title in 10 pt Times Roman, bold and uppercase. 1 has also the flexibility to combine quantitative and qualitative factors, to handle different groups of actors, to combine the opinions expressed by many experts, and can help in stakeholder analysis.The purpose of stakeholder analysis is to understand their behavior, expectations, relationships and influences or resources they can bring to the decision-making process 11 . 12 suggest that the increasing use of stakeholder analysis in natural resources management reflects the recognition that stakeholders can and should influence environmental decisionmaking processes. This approach is being promoted by the EU (Directive 2003/35/EC2), and by the U.S. the Environmental Protection Agency which promote citizen participation in environmental decision-m...