BIORETS: Conserving Water Resources and Riparian Biodiversity in a Desert Climate

Fresh water is a critical resource for both ecosystems and humans. In arid regions, water is withdrawn from rivers for urban and agricultural use, and river flora and fauna are lost. In arid climate, people also lose ecosystem services, such as cool riparian forests to visit during hot summers.

However, recent advances in wastewater treatment allow us to produce high quality treated effluent, which is suitable for restoring flow in dried rivers and for recharging groundwater supplies. In this Biological Research Experiences for Teachers Site (BIORETS) program at the University of Arizona (UA), three cohorts of teacher participants will collaborate with ecologists and natural resource managers to address two main place-based research questions.

First, how does the release of effluent affect aquatic and riparian species in and along the Santa Cruz River in southern Arizona? Second, how do ecological communities change over time in these newly flowing ecosystems as plant and animal species return to the river? Teachers will work with academic mentors at UA, as well as with members of the local Tohono O’odham and Pascua Yaqui tribes, to collect and analyze data.

Teachers also will develop curricula for their K-12 students, have their students participate in ecological studies during the school year, learn about water resource conservation, and help reinvigorate community connections to the river.

Historically, treated effluent was generally of poor water quality and it degraded ecological conditions in rivers that received effluent. Although newer wastewater treatment equipment and technology have greatly improved effluent water quality, large knowledge gaps remain regarding how well effluent can mimic ‘natural’ water, restore ecosystem function, and enhance plant and animal populations in and along arid-land rivers.

These gaps are important to address because there are many competing demands for effluent, which could reduce its availability to restore flow in rivers. Additionally, numerous basic ecological processes can be studied in these novel urban ecosystems, including community assembly mechanisms such as species turnover and priority effects. In this BIORETS program at UA, teachers and researchers will quantify community structure of multiple taxonomic groups (aquatic invertebrates, riparian birds and mammals, turtles, and wetland plants) in five rewetted reaches of the river over three years, and compare observed patterns with data collected concurrently from nearby dry reaches.

Together, these data will elucidate mechanisms of community assembly in novel ecosystems while also providing municipal managers with real-time ecological data to inform water resource management decisions and enhance water supply sustainability in cities. The results of this research will answer important ecological questions, shape water management decisions in the Santa Cruz basin, and provide a model approach for other cities to adopt for restoring flow in rivers and beneficial ecosystem services for local communities.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.