We are proposing to model: (1) range shifts for five alpine mammal species and, (2) the degree to which plant-animal interactions may alter what is often assumed to be an inevitable transition of alpine meadows to woody dominated communities in the Sierra Nevada mountain range. Meadows provide critical habitat for alpine mammals, including Sierra Nevada bighorn sheep, a federally listed endangered species, and American pika. However, there is an acute lack of data on potential impacts of temperature shifts on bighorn sheep and pika, the other three mammals, and, more generally, the alpine zone in the Sierra Nevada. We will use remote sensing data, downscaled climate data, rangewide surveys of the mammals, and experiments on plant-animal interactions to model the relative influence of climate, topography, and vegetation on the distributions of the five mammal species, and, reciprocally, the influence that mammals may have on vegetation transitions. The critical aspect of the study is the testing of multiple models of projected vegetation transitions with and without variables representing shifts in mammal ranges and feedbacks from herbivory and granivory. This approach will allow us to evaluate the degree to which mammals can potentially “manage their own habitat” in the face of temperature shifts. Research on alpine ecosystems is a top priority for the USGS and other international and national organizations. The study is a cooperative effort to directly address four goals of the U.S. Climate Change Science Program, two strategic directions of the USGS Science Strategy, and numerous aspects of the USGS Global Change Science Strategy.
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