April 26, 2004

Climate change research focuses on precipitation levels

By Jennifer McNulty

It was a classic “aha!” moment. Driving along Highway 395 on the eastern side of the Sierra, climate change researcher Michael Loik suddenly saw the nondescript Caltrans snow fences along the roadway as untapped gold mines of information.

Michael Loik has received a $104,000 grant to explore long-term effects of altered snow depth on species composition, soil carbon and nitrogen levels, and water availability. Photo: Jennifer McNulty

Installed near Mammoth Lakes by the state highway department in the 1950s, the fences were constructed hundreds of feet upwind of the road to keep wind-driven snow off the highway. Each winter, snow drifts build up along the eastern side of the fences, helping keep the road open with minimal plowing.

Loik realized that for 50 years, those fences had been altering precipitation levels for nearby shrubs--precisely what Loik had been modeling in nearby research plots.

“It struck me that by looking at the shrubs on either side of the snow fences, we could evaluate the actual effects of higher and lower amounts of precipitation over time,” said Loik, an assistant professor of environmental studies at UCSC who began conducting climate change experiments in the Mammoth Lakes area in 1999.

Loik’s revelation resonated with the M. Theo Kearney Foundation of Soil Science, which recently awarded him a $104,000 grant to explore long-term effects of altered snow depth on species composition, soil carbon and nitrogen levels, and water availability.

The new project is a major boost for Loik and graduate students Alden Griffith and Holly Alpert, who are investigating the effects on the desert ecosystem of changes in precipitation caused by global warming. “It’s unusual to have this kind of temporal and spatial data for a climate change experiment,” said Loik.

Loik conducts his research at the headwaters of the Owens River in eastern California, which has been engineered to quench the thirst of greater Los Angeles. Loik evaluates the effects of precipitation on plants as well as the fate of water, which evaporates, recharges groundwater supplies, or runs off the surface, depending on rain and snowfall levels. He is the founding director of PrecipNet, an international network dedicated to focusing on the precipitation aspects of climate change.

“Precipitation patterns are expected to change as part of other global changes, like increases in carbon dioxide in the atmosphere, rising temperatures, rising sea levels, and the melting of polar ice caps,” said Loik. “But changes in rain and snowfall could potentially be a lot more important than changes in temperature, especially in the arid western United States.”

The Owens River is a key water resource for the rest of the state, noted Loik, whose work is of great interest to the Los Angeles Department of Water and Power, Southern California Edison, the California Department of Transportation, and the Mammoth Community Water District.

Like the rest of the state, the future of Mammoth Lakes is closely linked to water resources. With 3,500 residents, Mammoth is a geographically isolated winter resort area that hosts 26,500 visitors per day. With 12 million visitor days per year, the Inyo National Forest is a more popular destination than Yellowstone National Park, Yosemite National Park, and the Grand Canyon combined, said Loik.

Loik’s work seeks to fill a data gap that could bedevil the most determined planners and policy makers: There is no consensus on whether precipitation is expected to rise or fall with global climate change. The most highly regarded computer models predict effects that vary from a 20 percent reduction in precipitation to an increase of more than 200 percent.

Loik has responded by “embracing uncertainty” in his experimental design. Two shrubs are at the center of Loik’s work on vegetation: antelope bitterbrush and sagebrush. Each summer, Loik’s team simulates thunderstorms over some experimental plots and builds shelters that deflect water away from others. In the winter, they manipulate snow levels, which is why Loik’s insight about the snow fences was so valuable.

“We have to act out the range of possible scenarios to understand the different potential impacts on the ecosystem,” said Loik. “The goal is to apply our results to issues of land management and water policy. Decision makers have to plan for all contingencies to be able to mitigate or adapt to changes in river flows.”

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