Abstract
In the context of conservation, management, ecological restoration and others, ecosystem services (ESs) valuation and ranking, when meaningfully possible, allow to better frame our relationship with nature. The general objective of the thesis is to identify the demand in terms of ESs in order to achieve coherent, integrated and accepted public decisions. It is made of three case studies. The first case study identifies levels of consensus and divergence among stakeholders on the prioritization of ecosystem services provided by two French Mediterranean coastal lagoons areas. The second one investigates the impact of familiarity and academic information supply on citizens’ preferences for ESs issued by the Palavas lagoons complex. Finally, the third case study explores elicitation and aggregation methods of individual preferences for the Palavas lagoons complex. The thesis mobilizes the ordinal preference and behavioral economics theoretical frameworks. Data were analyzed using descriptive statistics, Q methodology and a multinomial logit model. The results show the usefulness of the concept of ESs and its valuation using non-monetary methods. Indeed, monetary approaches do not take into account the heterogeneity of preferences because they flatten the various values of nature by projecting them on the single monetary dimension, an approach which is often rejected by stakeholders. Also, depending on the non-monetary valuation and ranking of ESs, stakeholder types, academic information supply and familiarity with the ecosystems, the results show that preferences vary especially for provisioning and cultural services. On the other hand, there is a relatively high consensus of high interest for regulation and maintenance services. I recommend that public policies should use more the concept of ESs in the decision-making process. ESs translate the complexity of the environment into a series of functions in a common language understandable to all stakeholders in decision-making processes. Another recommendation is to take into account the diversity of stakeholders’ preferences for ESs. Indeed, such an integrative practice can prevent or contribute to reduce conflicts among stakeholder groups.