About Yosemite National Park, the famous naturalist and conservationist John Muir once said: “It is by far the grandest of all the special temples of Nature I was ever permitted to enter.”
With majestic granite cliffs, waterfalls, clear streams, giant sequoia groves and a wealth of biological diversity, this 1,169-square-mile wilderness boasts a rich natural and cultural history. It attracts more than 3.5 million visitors annually and hosts hundreds of researchers who, in the interest in preserving the park’s history and biodiversity, study everything from its archaeology to hydroecology.
Civil and Environmental Engineering Associate Professor Steven Loheide is among those researchers. With colleague Jessica Lundquist of the University of Washington and former postdoctoral researcher Chris Lowry, Loheide began conducting research in Yosemite in 2007 on a National Science Foundation-funded project focused on restoring mountain meadows in a changing climate.
Now in the second phase of that project, Loheide, master’s student Kyle Ankenbauer (left) and former postdoctoral researcher Chris Lowry received funding from the National Park Service to collaborate with Colorado State University ecologist David Cooper and the Yosemite hydrologist Jim Roche and restoration ecologist Sue Beatty on a study of how the park’s expansive Tuolumne Meadows has degraded over time.
Stream health is key to the study: Wide or deeply incised stream channels both cause a drop in water levels in the stream, which then causes a drop in the water table within the meadow, making it more difficult for native plants to access the groundwater they need to thrive in the dry Sierra Nevada summers.
In an effort to understand the mechanisms that maintain Tuolumne Meadows in a degraded state and make it difficult to restore, the researchers are focusing on the extent to which deer feeding reduces the willow population along stream banks and how willows along those banks affect sediment deposition. They also are studying how a drop in the water table over time affects soil moisture and the soil’s ability to retain the moisture necessary to support native wet meadow vegetation.
The researchers’ goal is to develop a broadly applicable modeling framework that links ecological and hydrological models and provides a scientific basis for conversations about whether to undertake a restoration project and how to design it.