Humans are becoming an increasingly urban species, pointing to the profound importance of understanding how urban ecosystems function. Cities are concentrated consumers of energy and resources and producers of various wastes, but they are also centers of social networks, innovation, efficiency, and solutions. The Central Arizona Phoenix Long-term Ecological Research Program (CAP LTER) includes scientists and students from a variety of disciplines focused on understanding cities as hybrid ecosystems with interacting environmental and human components. The scientific objectives guiding this research are: 1) to answer fundamental questions about ecological structure and function of urban ecosystems that require a long-term perspective and 2) to develop general theory and models to deepen understanding of cities as social-ecological systems. The CAP science program includes innovative investigations of land use and land cover change, social and ecological surveys and long-term experiments designed to test hypotheses about social and biophysical factors influencing energy flow, nutrient cycling and food webs in the city of Phoenix. In addition, CAP researchers are committed to partnering with stakeholders to develop pathways to designing resilient and sustainable cities, and educating urban dwellers of all ages and experiences. Ecology Explorers, the premier CAP education program, connects teachers and pre-college students with CAP scientists. CAP is also expanding the involvement of Phoenix residents in scientific research by working with community partners such as the McDowell Sonoran Conservancy, the Central Arizona Conservation Alliance, the Desert Botanical Garden, the Valley Permaculture Alliance, and numerous municipal agencies. Finally, the large, diverse, and rich database produced by CAP research continues to be a valuable and growing resource for a global community of scientists and students, city managers and decision makers, teachers, and the general public.
Understanding the structure and function of urban ecosystems remains central to the CAP enterprise. The central question is: How do the services provided by dynamic urban ecosystems and their infrastructure affect human outcomes and behavior, and how do human actions affect patterns of urban ecosystem structure and function and, ultimately, urban sustainability and resilience? This question highlights the interconnectedness of human motivations, behaviors, actions, and outcomes with physical and biological structure and function in urban ecosystems. The overarching goal is to foster social-ecological urban research aimed at understanding these complex systems using a holistic, ecology of cities perspective while contributing to an ecology for cities that enhances urban sustainability and resilience. A new theoretical focus is on urban infrastructure as a critical bridge between the system’s biophysical and human/social components. Infrastructure is thus central to the conceptual framework that guides all CAP activities. CAP researchers explore new social-ecological frontiers of interdisciplinary urban ecology in residential landscapes, urban waterbodies, desert parks and preserves, the flora, fauna, and climate of a riparianized desert city, and urban design and governance. Research activities are organized around eight interdisciplinary questions and 11 long-term datasets and experiments, and researchers are organized into eight Interdisciplinary Research Themes to ensure multiple perspectives are brought to bear on all questions. This structure will ensure CAP continues to make fundamental contributions to urban systems theory, knowledge, and predictive capacity while helping Phoenix and other cities cope with an increasingly uncertain future.
