Islas Marietas: strengthening polycentric governance in response to an MPA tourism ban

Marine Protected Areas (MPAs) worldwide are under increasing pressure to balance biodiversity conservation with the growing demands of tourism, often exacerbated by anthropogenic impacts on coastal ecosystems. Exogenous shocks, such as environmental or policy-driven events, can offer opportunities for shifts in natural resource governance. This longitudinal study examines how a 2016 tourism ban in Mexico Islas Marietas National Park, prompted by coral reef degradation, influenced its polycentric governance. We use a mixed-methods approach, analyzing data from 53 governance meetings held before (March 2015 to April 2016) and after (May 2016 to November 2017) the regulatory shock. We compare stakeholder participation, affiliation networks, rules, and institutions to assess changes in the polycentric governance system. Our results show an increase in stakeholder engagement and two new decision-making forums have emerged. Network analysis reveals a rise in network density and social ties, suggesting enhanced trust and collaboration among stakeholders, although individual stakeholder responses to the shock varied. The tourism ban triggered a shift towards formalizing collaboration agreements, increasing stakeholder involvement in shaping public use norms, and decentralizing revenue generation. The coastal MPA also implemented a specific regulatory framework with recalculated carrying capacity, improved monitoring, and stricter accountability for tour operators. The Islas Marietas case offers valuable insights into coastal management in the Anthropocene, emphasizing the need for adaptive polycentric governance approaches that foster collaboration, and empower stakeholders to safeguard the long-term sustainability of both marine commons and livelihoods.