Can fungi help the grasses of Texas cope with climate change?

"That's one of the sharpest aridity gradients on the planet," Miller said of the climatic shift from east to west Texas. "And it's an important boundary for species. A lot of species that occur in eastern North America hit their westernmost limits in Texas."

Miller, an associate professor of biosciences at Rice, and his research group study range limits, invisible biological dividing lines between where a species can survive and where it can't. In a world of changing climate, those lines are moving, and Miller and his students want to study and understand how they are moving and why.

Miller's team studies grasses and other species at eight field sites along a 580-mile stretch of I-10 from lush Lafayette, Louisiana, to sandy Sonora, Texas, about 170 miles west of San Antonio. They've begun a first-of-its-kind study to find out whether a strange, ancient marriage between native Texas grasses and their hidden fungal partners could position the plants to better withstand droughts that are expected to be more frequent and severe due to climate change.

"Range limits arise from stress," Miller said. "As plants go from very wet to very dry places, their drought stress increases. We expect drought stress to be an important limit on how far west a lot of species can make it, particularly eastern species. Because the further west you go, the greater the drought stress.

From left to right, Rice University graduate student Ali Campbell splits opens grass stem and collects a thin layer of tissue, which will be examined later under a microscope for the presence of symbiotic fungi. Credit: Jeff Fitlow/Rice University

From left, students Joshua Fowler, Ali Campbell and Sar Lindner carry gear they will use at a field site near Huntsville, Texas, to collect samples of native grass species as well as symbiotic fungi that live inside the grass. Credit: Jeff Fitlow/Rice University

Skidmore College student Sar Lindner (left) assists as Rice University graduate student Ali Campbell examines a grass stem for signs of symbiotic fungi during a field sampling expedition near Huntsville, Texas. Credit: Jeff Fitlow/Rice University

Rice University biosciences graduate student Joshua Fowler collects samples of grass species and their symbiotic microbial partners at a field site near Huntsville, Texas. Credit: Jeff Fitlow/Rice University