In this paper, we discuss the experience in the design, use and evaluation of a serious game about participatory management of national parks for biodiversity conservation and social inclusion. Our objective is to help various stakeholders (e.g., environmentalist NGOs, communities, tourism operators, public agencies, and so on) to collectively understand conflict dynamics for natural resources management and to exercise negotiation management strategies for protected areas, one of the key issues linked to biodiversity conservation in national parks. Our serious game prototype combines, techniques such as: distributed role-playing games, support for negotiation between players, and insertion of various types of artificial agents (decision making agents, virtual players, assistant agents). After a general introduction to the project, we will present project's current prototype architecture and results from game sessions, as well as some prospects for the future, namely: the design of assistant artificial agents and of virtual players and the integration of a viability-based simulation engine.