Climate

Can Restored Meadows Fight Climate Change? California Seeks to Find Out

California's cap-and-trade extension, passed by lawmakers this week, ensures continued study of whether Sierra Nevada meadow restoration can capture carbon pollution and help birds at once.

Just past sunrise in late May, Kelly Franson sat cross-legged in a wet meadow glistening with dew. Ignoring the rattle-calls of a nearby Sandhill Crane, she fixed her gaze on a clump of willows 10 yards away. Each flash of white breast feathers among the thatch of gray-green leaves, each fragment of stuttered song confirmed the existence of a Song Sparrow nest she found days earlier by parting willow branches with a stick: three russet-speckled eggs, each barely larger than a thimble.

This is one of dozens of nests built by six meadow species that Franson will monitor through the end of July. She’s documenting how many chicks hatch, how many fledge, and what the birds do as they flit around the 290-acre Childs Meadow, which sits at 5,000 feet in the still-snowy mountains of northeastern California. She knows that the details she records—each bird's flight to Gurnsey Creek behind her, each flight back with a beetle in its beak—stand for so much more.

"These birds are indicators of what's going on in the habitat,” Franson, a research intern with the nonprofit Point Blue Conservation Science, says. “Water, climate—it's all connected."

Franson’s work is one of eight studies on carbon storage in Sierra Nevada meadows, all of which are part of California's pioneering cap-and-trade legislation to reduce carbon emissions. Combined, the meadow studies are estimated to cost $5.9 million to restore 30,000 acres by 2030—a drop in the bucket compared to the $3.4 billion the California Air Resources Board has invested to date to reduce the state's carbon emissions. The research is led by the Sierra Meadows Partnership, a group of some two-dozen government, university, and non-profit partners that together are investigating how restoring Sierra Nevada meadows might affect California’s water supply, biodiversity, and potential to store the greenhouse gases that are changing Earth’s climate. If meadows prove able to capture and store carbon underground, then the fees companies pay to offset their own pollution through cap-and-trade would go to their restoration. 

This week, the research got a boost when on Monday, July 17, a bipartisan group of state lawmakers voted to extend the cap-and-trade program through 2030. The extension could channel additional funds to critical bird habitat throughout the Sierra Nevada in meadows that are capturing carbon emissions.

Childs and other wet meadows represent a scant two percent of the mountainous region that lies along California's eastern border, and yet they play an outsized role in its hydrology and ecology. Each spring, when meltwater spills out of the Sierra snowpack, the meadows function as sponges, storing the excess water and slowly releasing it. They provide some 60 percent of California’s developed water supply and offer prime habitat for wildlife. Nearly every bird species that breeds in or migrates through the range uses the meadows.

As vibrant as the meadows seem now, they’re shadows of their former selves. A century of grazing, logging, mining, and road building has degraded half of their 191,000 acres by draining the water that nurtures plants, provides wildlife habitat, and facilitates carbon storage. The collapse has taken a devastating toll: About one-quarter of the Sierra species dependent on riparian habitat are at risk of extinction. All three breeding-bird species most closely tied to the region—Great Gray Owl, Willow Flycatcher, and Greater Sandhill Crane (a subspecies)—are listed in California as threatened or endangered.

The Sierra Meadows Partnership should help these species, even though its primary goal relates to climate change. Scientists know soils store three times more carbon than vegetation and the atmosphere combined. It’s stored in plants’ deep root systems, and in the accumulation of their dead tissue over time. But changes to the landscape have limited or reversed centuries of carbon storage. Degraded meadows store less carbon, and warmer temperatures from climate change may release carbon back into the atmosphere.

The Sierra Meadows Partnership is focused on identifying how much carbon meadows are storing, how much they are losing, and whether restoration makes a difference. The group has identified 16 meadows ranging in elevation from 3,045 to nearly 8,700 feet; half are being restored, while the others will serve as control sites that allow scientists to measure the effects of restoration. Some projects monitor changes in plant composition, others amphibians, and still others birds, but they share a common focus: All are using identical methods to measure greenhouse gases in meadow soils. And in the process, they’re creating crucial habitat for wildlife.

Kelly Franson, a research intern with Point Blue Conservation Science, observes Song Sparrows in and around a nest in Childs Meadow. Photo: Jane Braxton Little

On that May morning, Franson waded from her Song Sparrow nest site upstream along Gurnsey Creek and across the soggy meadow to a dry spot where Kristen Podolak dumped water out of her rubber boots. The women are among the scientists monitoring different aspects of the restoration in Childs Meadow. Podolak, an ecologist with The Nature Conservancy, is particularly interested in the restoration’s effects on two imperiled native species: Cascades frogs and Willow Flycatchers, one of Franson's six focal birds.

Podolak helped design the Childs Meadow project to study how raising the groundwater affects carbon sequestration. In a healthy meadow, beaver dams raise the water table, which encourages the growth of willows and also increases carbon storage. But a century of cattle grazing degraded the habitat, and currently no beavers live in the 80 acres of Childs Meadow designated for restoration. So the researchers built their own dams. Late last summer, they pounded stakes into Gurnsey’s streambed, and then wove willow branches and hay between them to form a barrier and cause water to pool. They also planted 700 willows and fenced out cattle in portions of the meadow. The project cost $30,000, with volunteers providing the labor, Podolak says.

By flooding the meadow, the makeshift beaver dams should increase groundwater levels by as much as 10 percent over three years. Podolak hopes that will increase wet habitat by 60 percent and invite Cascades frogs and Willow Flycatchers to breed in one of their few remaining Sierra strongholds. Some of the effects are already visible. The dams held through the winter, storing water in sometimes knee-deep pockets, and generating a carpet of native camas lilies and sedges.

To study the dams’ effects on carbon storage, Podolak and scientists from University of California, Davis, take regular measurements of greenhouse gas emissions using sealed chambers pushed into the soil and syringes to draw samples of whatever emissions they capture. By analyzing samples taken over several months at Childs and a nearby unrestored meadow, they can determine the effects of the dams on carbon storage and project their potential to slow climate change.

"We'll see," Podolak says. "This is science. You don't always get what you expect."

It’s too soon for Childs and the Sierra Meadow Partnership's other meadows to show the effects of restoration, but scientists have studied other sites restored over decades. A 2014 study, published by Point Blue Conservation Science, found that restored meadows in the northern Sierra Nevada have the potential to support up to 10 times more breeding bird species and individuals than degraded sites. And preliminary results from a study of meadows restored between 2001 and 2016 found 20 percent more soil carbon, on average, in restored meadows compared to degraded ones.

If these results hold true for the partnership’s study, then meadow restoration could be verified as a legitimate way to reduce carbon pollution in California's cap-and-trade program. That would release money from polluting companies to restore even more meadows in the Sierra Nevada.

Childs Meadow is now bustling with little birds peeping and demanding food. So far, Franson has not seen or heard any Willow Flycatchers there, but she and her fellow nest-searchers have recorded 41 Song Sparrow nests, along with those of MacGillivray’s Warblers and three other species. If previous studies are verified, those numbers will only increase; before long Childs Meadow will be full of birds that may even include Willow Flycatchers. And under the surface, soils and roots could be storing carbon, proving that restoring habitat can help local and global life at once.

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