ASU ecologist on vanishing rivers, vanishing species


Iti Agnihotri

John Sabo is an ecologist and water resources specialist at Arizona State University. A lot of his recent work investigates how climate change affects water sustainability, and how water cycles influence animal populations.

Drawing on this breadth of expertise, Sabo has commented on new research published this week in PNAS, the Proceedings of the National Academies of Sciences. The research, by Ohio State University researcher Kristen Jaeger and colleagues, looks at drought, drying rivers and animal extinction in the face of climate change. The researchers developed a first-of-its-kind method to investigate these issues, ultimately predicting a loss of fish habitat due to climate change.

Sabo's published commentary breaks it down. Jaeger and her co-authors, says Sabo, have combined fundamental principles of ecology, a tried-and-true computer model for calculating surface water flows, and forecasted climate data – downscaled to a fine-enough scale that could actually be relevant to fish.

The researchers used the climate data to adjust how the surface water model calculated its predictions. And then, to be sure it worked as expected, they simulated historical situations and compared the model's results against actual historical data. Then they predicted the future: sections of rivers will dry up, fragmenting animal habitats more extensively.

This prediction, perhaps, is not surprising. What makes the paper appealing is how Jaeger et al. have used the science – ecology and water resources – to analyze fish survival under conditions of climate change. By incorporating knowledge about how fish move or relocate when there is water, the researchers determined that as dry stretches widen, it will be increasingly likely that fish will be isolated, unable to move beyond dry stretches. Sabo notes previous research showing that river fragmentation can be bad news for species survival.

"This approach to measuring habitat fragmentation in intermittent rivers is the first of its kind and will be immediately relevant and extendable to rivers across the U.S. Sun Belt and in parts of the Corn Belt, where drought prevails regularly," notes Sabo in his commentary.

"This paper is groundbreaking, not just because it achieves a great synthesis of climate, surface water hydrology and ecology, but also because it opens up possibilities for further innovation."

John L. Sabo is a professor in ASU's School of Life Sciences and a senior sustainability scientist in the Julie Ann Wrigley Global Institute of Sustainability, where he serves as director of research development.