Marine protected areas (MPA) play a central role in marine conservation. Conservation planners design MPA networks and guide implementation of conservation actions by identifying potential conservation areas. Criteria for regional networks are that they should be representative of biodiversity and promote its long-term persistence and the processes that sustain it. In order to ensure long-term persistence, planners need to consider the open nature of marine ecosystems and linkages between realms. MPAs are highly vulnerable to natural resource development and exploitation outside their boundaries, as well as to degradation from coastal development. Logging, agriculture, and urbanization are affecting marine coastal habitats and communities through altered fluxes of sediments, nutrients, and pollutants. These problems cannot be alleviated by MPAs alone and demand planning for integrated implementation of conservation actions in the land-sea continuum. While methodologies to incorporate land-sea connections in coastal planning are developing, most reserve selection methods have not embraced an integrated approach. Recent advances in theories and tools in conservation planning can contribute to overcome these limitations and to explicitly incorporate land-sea connections. However, additional scientific knowledge is needed to address cross-system threats and to manage the complexities of conservation across realms. My project will review theory and practice in land-sea conservation planning in order to develop an operational framework. I will use the Gulf of California as a case study to develop and test this framework and to identify gaps in research, planning, and implementation. I will explore methods to identify land areas important for marine conservation (i.e. potential sources of sediments, nutrients and pollutants) and how these can change in time, based on a coastal catchments model (CCM) and a land-use change model. A spatial comparison of downstream (CCM) and upstream (i.e. biodiversity, ecosystem services) land values, supported by multicriteria analyses, will address the potential trade-offs resulting from competing values and ongoing habitat loss. Finally, I will model the potential impact of land-based impacts, based on estimates of river plumes (dispersal model), and use these results and previous models to create an integrated land-sea plan.