| morphological and dietary responses of chipmunks to a century of climate change. | predicting how individual taxa will respond to climatic change is challenging, in part because the impacts of environmental conditions can vary markedly, even among closely related species. studies of chipmunks (tamias spp.) in yosemite national park provide an important opportunity to explore the reasons for this variation in response. while the alpine chipmunk (t. alpinus) has undergone a significant elevational range contraction over the past century, the congeneric and partially sympatric lo ... | 2016 | 26732228 |
| contrasting stress responses of two co-occurring chipmunk species (tamias alpinus and t. speciosus). | glucocorticoid (gc) hormones are important mediators of responses to environmental conditions. accordingly, differences in gc physiology may contribute to interspecific variation in response to anthropogenically-induced patterns of climate change. to begin exploring this possibility, we validated the use of fecal cortisol/corticosterone metabolites (fcm) to measure baseline glucocorticoid levels in two species of co-occurring chipmunks that have exhibited markedly different patterns of response ... | 2015 | 25461808 |
| cache site selection by chipmunks (tamias spp.) and its influence on the effectiveness of seed dispersal in jeffrey pine (pinus jeffreyi). | the effectiveness of jeffrey pine (pinus jeffreyi) seed dispersal performed by seed-caching yellow pine chipmunks (tamias amoenus) and lodgepole chipmunks (tamias speciosus) was compared to that of wind dispersal in the sierra nevada of western nevada. wind-dispersed seeds typically fall under or near the parent tree. chipmunks removed 90 and 97% of 1064 radioactive seeds from each of two simulated wind-dispersed seed shadows in less than 24 h. "wind-dispersed" seeds were deployed within 12 m of ... | 1993 | 28313421 |
| host biology and environmental variables differentially predict flea abundances for two rodent hosts in a plague-relevant system. | while rodents frequently host ectoparasites that can vector zoonotic diseases, often little is known about their ectoparasite communities, even in places where hosts frequently interact with humans. yosemite national park is an area of high human-wildlife interaction and high potential zoonotic disease transfer. nonetheless, relatively few studies have surveyed the flea communities on mammalian hosts in this area, and even fewer have characterized the environmental and host factors that predict ... | 2019 | 31193431 |
| plague epizootic dynamics in chipmunk fleas, sierra nevada mountains, california, usa, 2013-2015. | we describe yersinia pestis minimum infection prevalence in fleas collected from tamias spp. chipmunks in the sierra nevadas (california, usa) during 2013-2015. y. pestis-positive fleas were detected only in 2015 (year of plague epizootic), mostly in t. speciosus chipmunks at high-elevation sites. plague surveillance should include testing vectors for y. pestis. | 2020 | 31922951 |
| glucocorticoid-environment relationships align with responses to environmental change in two co-occurring congeners. | as more species undergo range shifts in response to climate change, it is increasingly important to understand the factors that determine an organism's realized niche. physiological limits imposed by abiotic factors constrain the distributions of many species. because glucocorticoids are essential to the maintenance of physiological homeostasis, identifying glucocorticoid-environment relationships may generate critical insights into both limits on species distributions and potential responses to ... | 2018 | 30043471 |
| ecological specialization, variability in activity patterns and response to environmental change. | differences in temporal patterns of activity can modulate the ambient conditions to which organisms are exposed, providing an important mechanism for responding to environmental change. such differences may be particularly relevant to ecological generalists, which are expected to encounter a wider range of environmental conditions. here, we compare temporal patterns of activity for partially sympatric populations of a generalist (the lodgepole chipmunk, tamias speciosus) and a more specialized c ... | 2018 | 29950317 |