Central Arizona – Phoenix LTER

The Central Arizona–Phoenix Long-Term Ecological Research (CAP LTER or CAP for short) program advances research on urban ecology and urban socio-ecological systems of the Phoenix Metropolitan Area and surrounding Sonoran Desert in central Arizona. CAP is a multi-disciplinary investigation aimed at understanding not just the ecology of the city but also contributing to an ecology for the city and the wellbeing of its residents. The central research question that guides the project's research is: How are human-environment interactions mediated by urban ecological infrastructure to shape the Phoenix urban ecosystem - past present and future? To address this question, CAP collects data from over a dozen long-term projects conducted across five integrative project areas. In addition, CAP conducts synthesis activities across all project areas, focusing on results from the first 25 years of CAP research, as well as activities to construct scenarios of future change in Central Arizona.

Ecosystem structure and function: Energy flow and material cycling in ecosystems are the processes that support other ecosystem services, and as such, are often hidden from human perception and inadvertently managed. On the other hand, deliberate human manipulation of nutrient cycles has supported societal advances such as the "green revolution" and infrastructural improvements. Research in CAP has long centered on understanding how urban biogeochemical cycles differ from those of undeveloped ecosystems and the consequences of those altered cycles for human wellbeing. The organization of this research is multi-scaled, from individual households/yards and agricultural or desert plots to the regional socio-ecological system.

Organismal eco-evolutionary dynamics: Urbanization profoundly alters the composition, abundance, and distribution of non-human species. Habitat alteration, climate modification, shifting nutrient and water availability, and introduction of nonnative species often result in a complete restructuring of biotic communities. CAP investigates how species’ life history traits respond to and shape eco-evolutionary dynamics and responses to these human-induced changes in the urban environment.

Urban heat and air quality: Our work will advance basic science while facilitating decision-making about the mitigation of and adaptations to environmental change in arid socio-ecological systems. We investigate the spatial and temporal relationships between heterogeneous urban ecological infrastructure and urban heat, air and water and how urban ecological infrastructure influences these parameters to affect people, plants and animals. To do so requires incorporating demands on resources (landscape, water, and energy), stakeholder perceptions of heat and air, economic indicators, and human vulnerability indicators (heat-related comfort, morbidity, and mortality).

Environment and human wellbeing: CAP studies the effect of residents’ interaction with nature on management decisions and subsequent human wellbeing. This is achieved through co-production with communities of practice to integrate the multiple ways people experience nature–expressed through perceptions, management decisions and wellbeing–as it is shaped by the distribution of urban ecological infrastructure and associated ecosystem services and ecosystem disservices.

Governance and future transitions: Using the long-term conclusions from CAP socioecological datasets, we study how governance — and associated institutions, values and knowledge — shapes past, current and future transformational capacities, and how those capacities affect the distribution of urban ecological infrastructure and associated ecosystem services and ecosystem disservices to impact the residents of the Phoenix Metropolitan Area. We develop future scenarios for the central Arizona socio-ecological system that address the critical question: how do biophysical drivers (e.g., heat, water availability) and societal drivers (e.g., the pattern of land-use change) influence the interaction and feedbacks between ecosystems and society as mediated through ecosystem services, and thereby influence the future of the urban socio-ecological system?

The Central Arizona-Phoenix Long-Term Ecological Research (CAP LTER) project is one of 26 LTER sites funded by the National Science Foundation. It is one of two LTER sites funded by the National Science Foundation that specifically studies urban ecology. Launched in 1997, CAP LTER has been instrumental in establishing urban ecology as a recognized and important area of ecological inquiry. The central research question that guides the project's research is: How are human-environment interactions mediated by urban ecological infrastructure to shape the Phoenix urban ecosystem - past present and future? How can we use knowledge of these relationships to transform the future of the Phoenix Metropolitan Area? With an emphasis on ecosystem services, human wellbeing, and change, we ask three subsidiary research questions corresponding to different portions of our conceptual framework:

• Urban ecosystem services: How does urbanization change the structure and function of ecosystems and thereby alter the services provided by those ecosystems?
• Human outcomes and actions/responses: How do people perceive and respond to ecosystem services, how are the services’ effects distributed spatially and with reference to characteristics of the population, and how do individual and collective behaviors further change ecosystem structure and function?
• Urbanization in a dynamic world: How does the larger context of biophysical drivers (e.g., heat, water availability) and societal drivers (e.g., regional urbanization) influence the interaction and feedbacks between ecosystems and society as mediated through ecosystem services, and thereby influence the future of the urban ecosystem?

In addressing these questions, CAP LTER researchers focus on a broad geographic area in central Arizona and metropolitan Phoenix where two major desert tributaries of the Colorado River, the Salt and Gila Rivers, converge. The edges of this geographic focal area remain fluid to allow scientists to investigate urban influences beyond these boundaries, conduct comparative work, and examine issues related to the growing megapolitan area between the greater Phoenix and Tucson areas. CAP LTER's conceptual framework illustrates the major press and pulse events that drive changes in the geophysical and socio-cultural-economic templates. Land-use change, land-cover change, and their legacies are important for CAP research. Other changes to the desert ecosystem through housing and urban infrastructure development, the construction and management of urban landscapes, and alterations to the hydrologic system are also important press events. CAP addresses these issues through a series of long-term monitoring and experimentation efforts as well as other projects to elucidate patterns and processes in the urban socio-ecological system.