While climate change literature focused on animals tends to focus on climate-matched range shifts in which species show movement upward in elevation or latitude to track their climatic niches, there are many species that maintain the same range boundaries. These species must be making in situ adjustments, likely in behavior and physiology, to cope with their changing environments. The lodgepole (Tamias speciosus) and alpine chipmunks (T. alpinus) in Yosemite National Park, CA are two closely related species that have dealt with the past century of human-induced climate change differently: T. alpinus's range has moved upwards, while T. speciosus's overlapping range has not significantly shifted. This research explores the question of why one species range would shift while its co-occurring counterparts range does not. This research is important because determining the immediate mechanisms that shape these responses are critical to understanding what is happening, and predicting what will happen, as environmental change progresses. Undergraduate field assistants will work with the researchers and the National Park Service education and outreach program in Yosemite, where the researchers will interact with visitors and discuss ongoing research in the park. Additionally, the researchers will work with Bay Area Scientists in Schools to develop and teach grade-school lessons. One of the researchers will also tutor at Berkeley High School and become a co-leader of the Berkeley Women in Science group, which is devoted to increasing women's representation at all levels of science. These outreach efforts will not only increase scientific literacy in the public, but also will strengthen bonds between government and academic research efforts.
This research will examine the roles of stress physiology and behavior in different parts of these species' elevational ranges. The researchers hypothesize that elevational range boundary adjustments for T. alpinus are determined more by intrinsic physiological tolerances than interspecific interactions, as is thought for T. speciosus. Additionally, the researches hypotheize that stress hormone levels are related to the animals activity budgets. To test these hypotheses, the researchers will conduct vegetation surveys, collect temperature data using iButton and collect fecal samples to measure glucocorticoid (GC) metabolites. In addition, 6 chipmunks from each species will be tagged with remote sensing units equipped with an accelerometer & gyrometer, a light sensor, a pressure sensor (which will allow for determination of elevation), and a temperature sensor. After the accelerometer data have been automatically translated into behaviors using a semi-Markov model, the overall percent time spent on each behavior for each individual will be calculated. A generalized linear mixed model in the computer program R will then be used to test how different environmental parameters (elevation, species co-occurrence, temperature [daily average/high/low], time of day, vegetation category, human impact score) are related to behavioral patterns and GCs. Lastly, iButton data will be used to determine how time-of-day is related to temperature and this information will be incorporated in statistical models to test predictions about how each species partitions its activity over the day relative to temperature and activity of the heterospecifics.
