Interdisciplinary teams of Center scientists are investigating the causes for the decline of salmon and steelhead in Shasta River, historically one of the most productive tributaries in the lower Klamath Basin. A large spring complex (Big Springs Creek) provides the majority of its water, particularly during the summer.

In 2008, Center researchers seized a rare opportunity to quantify the results of conservation action on a large scale. The Nature Conservancy bought ranchland along Big Springs Creek, a Shasta River tributary that had been degraded by cattle grazing. The conservancy continued ranching but fenced out cattle along the 2.2 mile stream.

Over the last half century, the Foothill Yellow-legged Frog (R. boylii) has declined dramatically, especially in Southern California and the southern Sierra Nevada mountains.

This study compares commonly used methods of defining habitat suitability criteria and applying those to instream flow models for R. boylii in the Sierra Nevada of California. First, regional habitat suitability criteria (HSC) are developed using standard univariate and multivariate techniques, and the predictive performance and transferability of different HSC methods are evaluated. Second, three of the most commonly used instream flow assessment techniques are evaluated: (1) one-dimensional habitat modeling, (2) two-dimensional hydrodynamic modeling, and (3) expert habitat mapping (judgement-based mapping by species experts). A comparison table is provided to aid resource managers in selecting the most appropriate habitat assessment method for R. boylii given the specific conditions of a hydropower relicensing project.

Mountain meadow wetlands provide disproportionally important ecological services as compared to the area they cover in the Sierra Nevada by providing wetland-associated biodiversity, attenuating floods, and by contributing to downstream water quality and flow. However, degradation and loss of hydrologic function are widespread in Sierran meadows due to past and continuing anthropogenic effects including grazing management, diversions, roads and culverts, as well as non-native species.