A project to better understand how humans impact the environment in arid region stream corridors is getting a $1.4 million boost from the National Science Foundation.
A multidisciplinary, international team including six University of Arizona units coordinated at the Udall Center for Studies in Public Policy will receive the award. The project will give stakeholders the knowledge they need to make decisions beneficial for their land and the environment.
"Climate change, water use and land-use decisions threaten the supply of stream flow and shallow groundwater that these corridors depend on," said principal investigator Christopher Scott, an associate research professor of water resources policy at the Udall Center and an associate professor in the UA's School of Geography and Development.
"Ecological, climatic and human stresses can quickly push these river systems over critical thresholds until they reach a tipping point that makes the return to sustainable conditions unlikely."
As a result, the area around riparian corridors becomes more vulnerable to environmental stresses such as drought, fire or invasion of non-native species.
The award funds a five-year study of interactions among land and water use, climate change, hydrology, water management and policy for two streamside, or riparian, corridors in Arizona and Sonora, Mexico.
Fed by seasonal rainwater runoff or melting snow, these corridors shelter some of the most important biodiversity in the arid Southwest, provide a habitat for wildlife and vegetation and allow nutrient exchange that is crucial to environmental sustainability.
Scott and his colleagues will conduct their research in two adjacent river systems centered approximately 100 miles southeast of Tucson: the Upper San Pedro River, which flows northward from Sonora, Mexico, into Arizona, and the Upper Sonora River, which crosses Sonora on its way to the Gulf of California.
The research team will develop an "agent-based" computer model to represent how humans influence and respond to environmental conditions in the watersheds.
Processes such as changing vegetation (trees encroaching on grasslands) and altered flood regimes (more monsoon, less winter rainfall) can interact with each other and modify human responses, leading to broader changes in the ecosystem. Of particular interest are stresses brought about by climate change in combination with social and economic pressures generated by activities such as in- and out-migration, mining, commercial activities and urban expansion.
The model will incorporate programs for individual "thinking" agents to represent the decision-makers – landowners, governmental and private agencies – whose choices will impact riparian areas. The model gives stakeholders from water managers to recreational users a science-based tool to explore how their decisions might affect riparian corridors and help them make the best policy decisions for sustainability of their land and watersheds.
While sharing a similar setting in terms of climate and ecology, the Upper San Pedro and Upper Sonora watersheds exist in nations with very different legal, economic and cultural conditions.
"This provides a unique test-bed to understand differing human pressures and responses to a range of environmental changes," said Scott.
"Given the generational time spans over which changes and societal responses can occur, the project includes educational components for K-12 and the general public," he added.
Team members will visit local schools to educate children on the issues affecting riparian corridors and encourage them to think about how human decisions and environmental changes affect each other. In a way, the children will participate in agent-based modeling: as future decision-making agents.
The UA's Biosphere 2 will serve as a venue to share information about the project with the public.
In addition to Scott, the interdisciplinary research team comprises members from five UA colleges and two universities in Mexico and one in Denmark.
UA members include: Mitchell Pavao-Zuckerman, assistant research professor with Biosphere 2 Earthscience and assitant professor at the UA's School of Natural Resources and the Environment; Barbara Morehouse, deputy director of research and associate research scientist at the UA's Institute of the Environment and adjunct associate professor at the School of Geography and Development; Thomas Meixner, associate professor and interim head of the department of hydrology and water resources in the College of Science; Kevin Lansey, professor and head of the department of civil engineering and engineering mechanics; and Randy Gimblett, professor in the School of Natural Resources and the Environment.
The UA team will be joined by Alejandro Castellanos and Miguel Rangel, professors at the Universidad de Sonora; José Luis Moreno, professor at El Colegio de Sonora; and Hans Skov-Petersen, professor at the University of Copenhagen.