Rice ecologists study climate impacts in New Mexico

NSF funds long-term study at Sevilleta National Wildlife Refuge

Rice University ecologist Tom Miller and his students will take part in a new $6.4 million research project aimed at better understanding the long-term impacts of climate change on dryland ecosystems.

The Sevilleta Long-Term Ecological Research (LTER) project, which is funded by the National Science Foundation, will bring together ecologists from the University of New Mexico (UNM), Rice and the University of Northern Arizona (UNA) to examine yearslong effects of climate variability at the 230,000-acre Sevilleta National Wildlife Refuge in central New Mexico.

Rice University ecologist Tom Miller at a drylands field site near Ozona, Texas. (Photo by Aldo Compagnoni)

“When people hear ‘climate change,’ they often think ‘global warming,'” said Miller, an associate professor of biosciences. “In fact, climate change is more complicated than that. We are not only seeing average temperatures increase. We are also seeing an increase in climate variability. In the 10 years I have lived in Texas, for example, we have seen records for the hottest year, the wettest year, the worst fires and the largest floods. That is remarkable. And it is a fingerprint of global change.”

Miller, a co-principal investigator on the NSF grant, said it is a challenge for ecologists to understand and predict how increased climate variability will affect specific types of ecosystems.

“This is a wide-open question because variability manifests over long time scales, typically exceeding the lifetime of most research projects,” Miller said. “That’s why funding from NSF’s Long-Term Ecological Research program is so important. The LTER program is designed to tackle the big questions that can only be answered with decades of intensive study.

“At Sevilleta, for example, we’ll conduct experiments where we actually manipulate climate variability over many years to see how different ecosystems like desert grasslands, shrublands and woodlands respond to a more variable environment,” he said.

Arid areas like Sevilleta comprise more than 40 percent of land on Earth and are expanding in many places. Yearly differences in temperature and patterns of rain and snow greatly affect the ecology and evolution of plants and animals in these drylands. At Sevilleta, scientists will develop new theory to predict what happens when, for example, rainfall is extremely low in one year but high in the next.

This view from New Mexico’s Los Pinos Mountains captures transitions from pinon-juniper woodlands to desert grasslands in Sevilleta National Wildlife Refuge. (Photo by William Pockman/UNM)

“This LTER project includes the study of processes of vegetation change, consumer dynamics and carbon and nitrogen cycles that are fundamental to the function of dryland ecosystems,” said UNM ecologist and principal investigator Jennifer Rudgers. “An important goal of the Sevilleta LTER is understanding how and why dryland ecosystems change over time. Our new project focuses on the ecological consequences of two key aspects: rising temperatures and increasingly variable rainfall.”

Rudgers, Miller and co-principal investigators Marcy Litvak and Seth Newsome at UNM and Yiqi Luo at NAU will conduct experiments that alter the amount of rainfall on test plots across the Sevilleta LTER. They will combine long-term data with results of these experiments to build models that predict ecological change into the future. Ultimately, the researchers hope to improve forecasts for drylands and transform the understanding of these ecosystems worldwide.

“Long-term research is critical to ecology,” said Stephanie Hampton, director of the National Science Foundation’s Division of Environmental Biology, which funded the new LTER site. “Long-term data lead to findings that affect all of us, such as the discovery of the link between rodents and the Sin Nombre hantavirus, which can cause severe respiratory disease. This LTER program allows researchers to discover ecological phenomena, assess the pace and impacts of environmental change, and forecast a range of future ecosystem scenarios.”

For more information, visit the Sevilleta Long-Term Ecological Research homepage or the NSF’s LTER Network website.