This book addresses the integrated analysis and management of ecological-social systems and argues that the rational integration of local participatory land use planning and regional planning could enhance the sustainable management of resources. This matter was explored in two eco-social systems: the Aysén river watershed in Southern Chile and the Marano lagoon in North East Italy. Aysén region is threatened by the risk of water pollution due to the development of intensive aquaculture in its fjords. Marano lagoon and its hinterland has been declared a “polluted area of national concern” since human health is threatened by the concentrations of heavy metals in air, soil and water sediments. The research investigates three key issues pertaining to the ecosystem based approach of environmental management within the framework of post-normal science: the consequences of the lack of strategic and integrated planning, the long-term failure of top-down visions in natural resources management and the usefulness of multicriteria analysis to support participatory decision making.