Watershed interventions priority areas and ecosystem services from enhancing societal and ecological benefits through land-sea planning at multiple scales in the Mesoamerican region

Deforestation impacts the benefits coral reefs provide to coastal communities in multiple ways. Yet, connections between terrestrial and marine ecosystems are generally assessed at a single scale and from an ecological perspective alone. This limits understanding of how watershed management affects coastal systems and how benefits are accrued by communities at different scales. We explore how ecological and societal benefits of watershed interventions (restoration, protection, and sustainable agriculture) differ when considered regionally versus nationally in the Mesoamerican Reef region. We employ linked land-sea ecosystem service models to prioritize the three interventions at the two scales. With a regional approach, interventions can be prioritized in larger transboundary watersheds, resulting in overall more sediment retention and greater increase in healthier corals for neighboring nations. The national approach prioritizes non-transboundary, often smaller, watersheds, trading increases in coral health in neighboring nations for more societal benefits for each nation individually, especially decreased coastal risk and increased nature-based tourism. Our findings highlight the effect of scale on societal and ecological outcomes across and within nations. Planning at both scales can provide a win-win approach for the region by improving the health of forests and corals while increasing societal benefits.