The goal of our overall project is to determine the sources and consequences of changing land and coastal use in the Yaqui Basin, Sonora, Mexico, focusing on the linked upland, wetland, and estuarine ecosystems. These systems are linked by the movement of materials in air and water, and by many human economic and social activities. Thus, decisions that are made in one place can have profound implications for the entire region. This research provides an opportunity to explore the constraints on "sustainability" as it refers not just to individual agricultural fields or fisheries, but to an integrated, regional system that encompasses land use and decision making across the land-sea interface.