Browsing by Author "Huyvaert, Kathryn, committee member"

Now showing 1 - 6 of 6

Open Access
Ecophysiological and behavioral determinants of niche range in hibernating bats affected by white nose syndrome
(Colorado State University. Libraries, 2022) Golas, Benjamin D., author; Webb, Colleen, advisor; Cryan, Paul, committee member; Hayman, David, committee member; Huyvaert, Kathryn, committee member
The restrictions of a fundamental niche range, physiological conditions under which an organism can persist, becomes increasingly important as populations are subjected to extreme climatic conditions. Hibernating animals are annually subjected to such extremes. For example, insectivorous bats will survive months without caloric intake in winter by lowering body temperature to near freezing to mitigate loss of energy through heat transfer and water through evaporation. However, there is strong overlap between the fundamental niche of hibernating bats and that of the keratinolytic fungus, Pseudogymnoascus destructans (Pd). As a result of Pd growth disrupting wing membranes, hibernating bats are forced to enact frequent energetically costly arousals that can result in starvation and mortality. The resulting disease, white nose syndrome (WNS), has resulted in mass die offs of millions of hibernating bats across North America since Pd introduction. However, there is significant inter- and intraspecific variation in host responses, and the realized niche for bat hibernation may be wider and more variable than previously theorized, making host responses difficult to predict. Ecophysiological models predict torpor arousal and hibernation survival with WNS as a function of microclimates, but they are largely dependent on laboratory-based experiments measuring metabolic parameters like metabolic rate and evaporative water loss that are likely subject to intraspecific local variation. We require a better understanding of the physiological, environmental, and behavioral drivers of successful bat hibernation in natural systems with and without Pd so we can improve risk assessment and guide management strategies for populations affected by WNS. To better understand how torpor arousal is dependent on experienced microclimates, we attached temperature and humidity data loggers to free-ranging Eptesicus fuscus to record microclimates and arousal frequency throughout hibernation. Fitting this data to ecophysiological models describing torpor, we found that while ecophysiological models provide adequate boundaries to biological capabilities for arousal, stochasticity inherent in natural systems can lead to earlier and more frequent arousal than models suggest. To determine how hibernation roosting niche is constrained in spatiotemporally variable hibernacula, we measured microclimates throughout a hibernaculum where Myotis lucifugus populations have thrived despite regional WNS-related mass mortality. Using hierarchical modeling to predict spatiotemporal underground microclimates based on above-ground conditions, we find that hibernation roosts are likely established early in the hibernation season at microsites that are locally stable within a given hibernaculum chamber, but not necessarily the most stable across the hibernaculum. This suggests that M. lucifugus are capable of a more flexible niche space than previously theorized, which may assist in WNS survival. Lastly, we use approximate Bayesian computation to test different hypotheses for how bats survive WNS in this hibernaculum, using ecophysiological models and longitudinal microclimate data to compare local adaptation, microclimate selection, clustering, and grooming strategies. While grooming removal of Pd load appears to be essential to describe observed population survival, we find evidence of all four hypotheses contributing to biologically realistic survival. Ultimately, the indirect fundamental niche range contraction due to Pd disrupting physiological host processes is mitigated by a combination of adaptation and conspecific facilitation expanding realized niche range. Our work represents advancements in novel technological and modeling advancements that allow evaluation of niche range in free-living populations. The results of this study suggest that there are populations with exaptations that facilitate WNS survival, but that alteration of environmental conditions in other hibernacula could lead to a change in niche space outside the range for which residents are locally adapted. Our findings help to inform and guide assessment of at-risk species and inform potential management strategies by considering the significant individual- and population-level variation in local adaptation and microclimate use that can impact WNS survival.
Open Access
Epidemiology, ecology, and evolution of canine influenza virus H3N8 in United States dogs
(Colorado State University. Libraries, 2012) Pecoraro, Heidi Lee, author; Landolt, Gabriele, advisor; Blair, Carol, committee member; Bowen, Richard, committee member; Huyvaert, Kathryn, committee member
To view the abstract, please see the full text of the document.
Open Access
Genetic natural resistance to brucellosis in Yellowstone National Park bison (Bison bison): a preliminary assessment
(Colorado State University. Libraries, 2013) Herman, Julia Anne, author; Salman, Mo, advisor; Hill, Ashley, committee member; Huyvaert, Kathryn, committee member; Rhyan, Jack, committee member
As a nationally recognized symbol of perseverance and survival, the American bison (Bison bison) continues to be the focus of many conservation efforts. This is particularly true in Yellowstone National Park (YNP) where genetic diversity and population dynamics are threatened by the presence of Brucella abortus infection, the causative agent of brucellosis. To further complicate management efforts, the potential for transmission of B. abortus to livestock surrounding the park could have effects on human and animal health in addition to negative economic impacts. Genetic natural resistance to infectious diseases such as brucellosis has been examined in bison and other species. Consideration of using genetic natural resistance as a management tool within YNP relies on its applicability to the population and effectiveness in identifying susceptible or resistant animals. The aim of this study was to further investigate genetic natural resistance to brucellosis in bison using the prion protein gene (PRNP). This could provide a genetic management tool for future populations by identifying resistant and susceptible genotypes to brucellosis that governing agencies could screen when selecting animals for removal. Animals used in this study were part of the Bison Quarantine Feasibility Study (BQFS), which was conducted by state and federal government agencies to explore alternative options for bison that leave the protection of the park's perimeters as part of the Interagency Bison Management Plan (IBMP). After completing the study, the bison involved will be released into areas of their historic range and managed as a conservation herd. In addition to investigating genetic natural resistance, other genetic aspects were analyzed in this quarantine herd. We evaluated genetic diversity at 42 microsatellite loci representing each of the nuclear chromosomes in the bison genome. These markers allowed us to determine parentage which helped quantify the genetic diversity contained in the conservation herd. It was also important to understand the genetic diversity of the herd and to determine if any genetic characteristics such as cattle DNA introgression or low genetic diversity may threaten the protected status of this herd. Previously developed mitochondrial and nuclear DNA microsatellite markers were applied to determine if any introgression of domestic cattle DNA is presen. PRNP examination provided conflicting results from previous bison PRNP studies, justifying further research into the importance of PRNP in genetic natural resistance. As a conservation herd, this group of bison demonstrates high retention of unique YNP genetic diversity, high percentage of adult animals contributing offspring, and no evidence of cattle DNA introgression. This study explains support for using YNP bison as stocking animals for future satellite herds under the condition that BQFS protocol is followed. Results of these genetic analyses provide a thorough description of a quarantined herd of YNP bison destined for release to brucellosis-free public lands.
Open Access
Introduction and management of Myxobolus cerebralis-resistant rainbow trout in Colorado
(Colorado State University. Libraries, 2013) Fetherman, Eric R., author; Winkelman, Dana, advisor; Bailey, Larissa, committee member; Huyvaert, Kathryn, committee member; Angeloni, Lisa, committee member
To view the abstract, please see the full text of the document.
Open Access
Investigating factors influencing the probability of survival to metamorphosis of boreal toads at multiple scales
(Colorado State University. Libraries, 2019) Crockett, John, author; Bailey, Larissa, advisor; Muths, Erin, committee member; Funk, Chris, committee member; Huyvaert, Kathryn, committee member
To view the abstract, please see the full text of the document.
Restricted
The space between
(Colorado State University. Libraries, 2015) Ardelean, Jayla Rae, author; Thompson, Deborah, advisor; Calderazzo, John, committee member; Huyvaert, Kathryn, committee member
An exploration of natural and technological landscapes by examining the occupation or vacancy of spaces between loved ones, birds, and myself.