The Central Arizona–Phoenix Long-term Ecological Research (CAP LTER) project is based in the central Arizona and metropolitan Phoenix region, embedded in the Sonoran Desert. As the fifth-largest and, until recently, the fastest-growing city in the US, Phoenix is an excellent location for urban ecological research. Phoenix was established after the Civil War, initially one of several small towns surrounded by irrigated farmland. Continued agrarian expansion predated the explosive growth of housing in the second half of the 20th century. Because of this, land-use change and legacies are important foci for CAP research. Urbanization has brought massive changes in the hydrologic and transportation infrastructure and other designed features of the built environment, as well as importation of non-native species, a “riparianization” of the vegetation structure, and increased nighttime temperatures due to the urban heat island effect. These alternations of the native desert environment along with demographic, economic, and societal changes experienced in the 26 cities of the region have produced a dynamic, ever-changing environment that differs radically from the one encountered in the mid-19th century. Accordingly, CAP has focused on how patterns and processes of urbanization alter the ecological conditions of the city and its surrounding environment and how the ecological consequences of these developments feed back to the social system to generate future changes. A new emphasis of CAP is how this interaction will change as external drivers (climate change, globalization) affect the process of urbanization.

Research under CAP draws from multiple disciplines in the social, biological, physical, and engineering sciences. Through its twelve-year history, CAP has worked toward developing an integrative, synthetic science that brings several disciplinary perspectives together to examine a problem and ultimately to pose sustainable solutions to that problem. Here we present examples of ongoing initiatives from the five integrative research areas under CAP: land-use and land-cover change; climate and ecosystem dynamics; water policy, use and supply; fluxes of materials and socio-ecosystem response; and human control of biodiversity.