Thesis
PREDATION RISK FOR HOARY MARMOTS IN THE CHANGING CLIMATE OF WASHINGTON S NORTH CASCADES
Washington State University
Master of Science (MS), Washington State University
01/2021
DOI:
https://doi.org/10.7273/000002410
Handle:
https://hdl.handle.net/2376/124580
Abstract
Climatic changes can reduce habitat availability of high-elevation specialists such as the hoary marmot (Marmota caligata), a hibernating rodent of subalpine meadows and talus fields. Observed hoary marmot mean abundance in North Cascades National Park (NOCA) has declined by 74%, and though declines of other marmot populations have been attributed to increasing predation pressure, this relationship remains unexplored in NOCA. To examine the link between potential predators and hoary marmots in NOCA, I coupled surveys of hoary marmot vigilance behavior with estimates of predation risk based on predator diet composition and probability of use near hoary marmot colonies. We conducted 145 focal-animal surveys to determine the proportion of time hoary marmots spent vigilant. We surveyed 9,930 trap nights using 130 remote cameras and modeled predator occupancy using environmental covariates. We used genetic metabarcoding to identify predator and prey DNA in 413 scat samples. From camera traps and fecal DNA, we detected ten predator species in the study area, and we detected hoary marmots in the scats of five species. The proportion of observed hoary marmot predation was highest for coyotes (Canis latrans) (Χ2 = 31.78, p < 0.0001) at 50%. To our knowledge, we also report the first record of hoary marmots being consumed by Pacific martens (Martes caurina),which were also significant predators (proportion of observed consumption = 32%). Although I expected that predators with low-elevation habits would use sites with lower snow persistence, this prediction was supported only for coyotes, but not for other low-elevation predators. Combining probability of use estimates with observed hoary marmot consumption rates to develop a predation risk index, we found the risk was highest from Pacific martens (0.20) and lowest from Canada lynx (Lynx canadensis) (< 0.01). However, estimates of predation risk and human use of sites did not explain the variation in hoary marmot vigilance, despite hoary marmots allocating > 50% of their time to vigilance. Our findings of consumption of hoary marmots by predators are similar to other studies of imperiled marmot populations, highlighting the need to better understand the effect of climate-driven shifts in predator-prey ecology in NOCA.
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Details
- Title
- PREDATION RISK FOR HOARY MARMOTS IN THE CHANGING CLIMATE OF WASHINGTON S NORTH CASCADES
- Creators
- Logan Johnson Whiles
- Contributors
- Daniel H Thornton (Advisor)Lisa A Shipley (Advisor)Jason I Ransom (Committee Member)Kent C Keller (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Environment, School of the (CAHNRS)
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Number of pages
- 69
- Identifiers
- 99900606753101842
- Language
- English
- Resource Type
- Thesis