Trois essais sur les instruments de conservation de la biodiversité

Controversies surrounding land use change and biodiversity conservation reflect growing tensions between environmental and economic priorities. However, human development often proceeds at the expense of natural areas and biodiversity. Thus, land use change and habitat loss are among the main drivers of global biodiversity decline (IPBES, 2019). Here, we choose to address three instruments aimed at addressing biodiversity loss and promoting sustainability, namely Biodiversity Offsets (BOs) (economic instruments), conservation reserves or protected areas, and voluntary approaches. Other instruments include regulations (command-and-control approaches) and education and awareness measures (Darbi, 2020; Earl et al., 2010). The key contributions of these works are both practical through modeling approaches and theoretical through field exploration. Three case studies illustrate our approach, including two located in mangroves on the western coast of Madagascar, and one in Brussels, Belgium, derived from a development project that sparked controversy over the sharing of land use in recent years. We first focused on the definition of a model that aims to reconcile economic development and the necessary recovery time gap of biodiversity to propose an Offset Sustainable Price (OSP) per unit of developed land. The concept of Biodiversity Offsets was born around the 1970’s in the United States of America (USA) and became popular since the 2010’s. Much debated, it is perceived as the main solution to reconcile economic development and biodiversity conservation. We developed a multicriteria, dynamic, and spatially-explicit model aimed at reconciling economic and ecological objectives. The application to mangroves and aquaculture in Mahajamba bay, Madagascar, illustrates the analytical findings and, in particular, the undervaluation of current price of BOs. Secondly, through field exploration and a more institutional approach, we applied the Ostromian framework to identify the fairness of a delegated management of a mangrove ecosystem to local communities, located in the Menabe region, Madagascar. We examined the various dimensions of environmental justice to assess management practices and issue recommendations. Third, we produced a common framework combining the Capability Approach and the Viability Theory to produce a multicriteria - including aspects of well-being, and dynamic approach, consistent with a strong sustainability perspective and the United Nations’ Sustainable Development Goals. It sheds light on the collective aspect of sustainable land sharing decisions.