SF State team tests surprising new tools for slowing climate change

You may have heard that planting forests is an important part of fighting climate change. But have you considered the humble meadow?

This month, a group of researchers working out of San Francisco State University’s Sierra Nevada Field Campus received funding for a five-year study to determine if restoring degraded meadows to their former, more lush state could make these ecosystems more effective tools for slowing the pace of climate change.

Oliphant adjusts an instrument that measures how fast gases flow between the meadow and the atmosphere over an area about three football fields in size.

“Meadows have the greatest amount of native plant species diversity in the Sierra,” explained San Francisco State Professor Jerry Davis, chair of the University’s Department of Geography & Environment. Meadows also serve the important role of storing water from spring snowmelt — and, according to SF State Professor of Geography & Environment Andrew Oliphant, they’re surprisingly effective at pulling greenhouse gases out of the air through photosynthesis. In one area he studied, “during the peak of the growing season, the meadow was taking carbon dioxide out of the atmosphere at a rate similar to tropical rainforests,” he said.

Many of the region’s meadows aren’t reaching that potential, though. Grazing and the soil impacts of crisscrossed logging railroads have left them dried out and full of invasive plant species. The target of the SF State team’s research is one such degraded meadow: Red Clover Valley, 5,500 feet in elevation and largely covered in scrubby sagebrush after years of overgrazing by cattle. 

Baguskas disassembles “the cube,” a chamber that traps and measures gases around a one-meter-square patch of meadow.

In an attempt to restore Red Clover Valley, the nonprofit Sierra Fund and youth from the local Mountain Maidu tribe have been working to build artificial versions of beaver dams to mimic the effects of the meadow’s historical rodent inhabitants. The dams trap water from the spring snowmelt in order to make the area wetter. They also have a second, even more important role. “It’s a way to invite beavers, the ultimate environmental engineers, back into the ecosystem,” explained Assistant Professor of Geography & Environment Sara Baguskas.

Using a suite of specialized tools on the ground and in the air, the team of biologists, geographers and atmospheric scientists from SF State is tracking the results of that work — measuring how the meadow “breathes” gases in and out on a minute-to-minute basis and studying how the area’s soil and its assortment of plant species change over the course of years. They’ll also be looking elsewhere to provide benchmarks for the meadow’s progress. “We use reference meadows that haven’t been intensively grazed to get insight into what a less impacted meadow may look like,” Baguskas explained.

Davis sets up a research drone, one of several that the team is using to record the health and identity of meadow plants using specialized cameras.

By the project’s end, the researchers will see if the new artificial dams have restored Red Clover Valley to its wetter historical state. They’ll also have concrete data on whether a restored meadow can lock up greater amounts of greenhouse gases than its degraded counterparts.

“There’s so much that makes up what a meadow is,” said Oliphant. “It’s this classic interdisciplinary question, and it’s what makes working in teams like this necessary and also really rewarding.” During their fieldwork, the team will stay at SF State’s field campus, tucked in the mountains by the Sierra Buttes an hour away from their field site.

As the five-year project gets underway, the researchers are far from certain about what they’ll discover. It’s no laboratory experiment — while the presence of beavers would almost certainly make the meadow healthier, they can’t control how the animals behave. But that’s just part of the appeal for those who want to see the ecosystem return to its natural state. “I love the fact that that you don’t know exactly what’s going to happen,” said Davis. “The beavers aren’t going to follow your rules. They’ve got their own ideas.”