title: Relating sub-surface ice features to physiological stress in a climate sensitive mammal, the American pika (Ochotona princeps).
abstract: The American pika (Ochotona princeps) is considered a sentinel species for detecting ecological effects of climate change. Pikas are declining within a large portion of their range, and ongoing research suggests loss of sub-surface ice as a mechanism. However, no studies have demonstrated physiological responses of pikas to sub-surface ice features. Here we present the first analysis of physiological stress in pikas living in and adjacent to habitats underlain by ice. Fresh fecal samples were collected non-invasively from two adjacent sites in the Rocky Mountains (one with sub-surface ice and one without) and analyzed for glucocorticoid metabolites (GCM). We also measured sub-surface microclimates in each habitat. Results indicate lower GCM concentration in sites with sub-surface ice, suggesting that pikas are less stressed in favorable microclimates resulting from sub-surface ice features. GCM response was well predicted by habitat characteristics associated with sub-surface ice features, such as lower mean summer temperatures. These results suggest that pikas inhabiting areas without sub-surface ice features are experiencing higher levels of physiological stress and may be more susceptible to changing climates. Although post-deposition environmental effects can confound analyses based on fecal GCM, we found no evidence for such effects in this study. Sub-surface ice features are key to water cycling and storage and will likely represent an increasingly important component of water resources in a warming climate. Fecal samples collected from additional watersheds as part of current pika monitoring programs could be used to further characterize relationships between pika stress and sub-surface ice features.
authors: Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, United States of America.
authors: Jennifer L
authors: JL
authors: Wilkening
authors: Department of Ecology and Evolutionary Biology and Institute for Arctic and Alpine Research, University of Colorado, Boulder, Colorado, United States of America.
authors: Chris
authors: C
authors: Ray
authors: Department of Biology, University of Utah, Salt Lake City, Utah, United States of America.
authors: Johanna
authors: J
authors: Varner
mesh_terms: D000569:Americas; D000818:Animals; D057231:Climate Change; D017753:Ecosystem; D005260:Female; D005843:Geography; D007053:Ice; D007793:Lagomorpha / Q000502:physiology*; D008834:Microclimate; D013312:Stress, Physiological / Q000502:physiology
chemical_list: D007053:Ice