1 INTEGRATED MODELING AND ECOLOGICAL VALUATION

Understanding how anthropogenic and climate-induced changes alter ecological systems and evaluating the effects of alternative hydrologic profiles on these ecosystems are important concerns in the semi-arid West. The goal of the proposed research is to incorporate hydrologic, vegetation, avian, and economic models into an integrated framework to determine the value of changes in ecological systems that result from changes in hydrological profiles. We propose to develop a hydro-bio-economic framework for the San Pedro River Region (SPRR) that considers groundwater, streamflow, recreation, riparian vegetation, and the abundance, diversity and distribution of birds in the region that includes the San Pedro Riparian National Conservation Area (SPRNCA). The SPRNCA is in southern Arizona and encompasses a stretch of the San Pedro River, which flows north from Cananea, Mexico, enters the U.S. near Sierra Vista, and eventually reaches the Gila River, a tributary to the Colorado River. The San Pedro River is one of the last free-flowing rivers in the desert southwest. It contains stretches of gallery riparian forest and represents one of the last remaining semi-arid flyways. The SPRR provides critically important habitat for resident, seasonally resident, and migratory birds, but is threatened by a decline in groundwater due to pumping of the regional aquifer (Rojo et al. 1998; Stromberg et al