Graduate Degree Program in Ecology
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These digital collections include theses, dissertations, faculty publications, photographs, and datasets from the Graduate Degree Program in Ecology.
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Browsing Graduate Degree Program in Ecology by Author "Angeloni, Lisa, advisor"
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Item Open Access Experimental tests of risky augmentation scenarios using Trinidadian guppies(Colorado State University. Libraries, 2017) Kronenberger, John Andrew, author; Angeloni, Lisa, advisor; Funk, Chris, advisor; Ghalambor, Cameron, committee member; Hufbauer, Ruth, committee memberIncreased isolation of populations, and the subsequent reduction in genetic diversity, can exacerbate global biodiversity loss by contributing to inbreeding depression and reducing the ability of organisms to adapt to rapid environmental change. This has prompted some conservation biologists to consider augmenting isolated populations with immigrants as a means of demographic and genetic rescue. Augmentations are typically highly successful, but they are also controversial due to the risk of outbreeding depression or the introduction of maladapted alleles when immigrants are genetically or adaptively divergent. For my Master's thesis, I tested risky augmentation scenarios using mesocosm populations of Trinidadian guppies (Poecilia reticulata) in two separate controlled experiments. In my first experiment (Chapter 1), I augmented mesocosm populations derived from a single recipient source with genetically or adaptively divergent immigrants to assess their short-term demographic effects. Mesocosms that were augmented maintained greater abundance and recruitment than controls that were not. There was also a trend for populations to receive a greater benefit from immigrants that were genetically divergent than those that were adaptively divergent. I expanded upon these results in my second experiment (Chapter 2), in which I augmented mesocosm populations from two different recipient sources with immigrants spanning a greater range of divergence and monitored them over a longer time frame, including an additional control and genetic monitoring to determine the relative impact of demography and genetics. Despite no evidence for demographic rescue, I found genetic rescue in one recipient population. Divergent immigrants did not have a negative effect in almost all cases, and any positive effect they had depended on the genetic diversity, immigrant fitness, and recipient life-history traits. Together, these experiments provide strong evidence that immigrants can bolster population fitness despite being divergent, thereby supporting the use of augmentation as a management technique in dire situations when no safe immigrant sources are available.Item Open Access The use of acoustic collars for studying landscape effects on animal behavior(Colorado State University. Libraries, 2013) Lynch, Emma, author; Angeloni, Lisa, advisor; Wittemyer, George, advisor; Crooks, Kevin, committee member; Fristrup, Kurt, committee memberAudio recordings made from free-ranging animals can be used to investigate aspects of physiology, behavior, and ecology through acoustic signal processing. On-animal acoustical monitoring applications allow continuous remote data collection, and can serve to address questions across temporal and spatial scales. We report on the design of an inexpensive collar-mounted recording device and present data on the activity budget of wild mule deer (Odocoileus hemionus) derived from these devices, which were applied for a two-week period. Over 3,300 hours of acoustical recordings were collected from 10 deer on their winter range in a natural gas extraction field in northwestern Colorado. Results demonstrated that acoustical monitoring is a viable and accurate method for characterizing individual time budgets and behaviors of ungulates. This acoustical monitoring technique also provides a new approach to investigate the ways external forces affect wildlife behavior. One particularly salient activity revealed by our acoustical monitoring was periodic pausing by mule deer within bouts of mastication, which appear to be adopted for listening for environmental cues of interest. While visual forms of vigilance, such as scanning or alert behavior, have been well documented across a wide range of animal taxa, animals also employ other vigilance modalities such as auditory vigilance, by listening for the acoustic cues of predators. To better understand the ecological properties that structure this behavior, we examined how natural and anthropogenic landscape variables influenced the amount of time that mule deer paused during mastication bouts. We found that deer paused more where concealment cover abounded, and where visual vigilance was likely to be less effective. Additionally, deer paused more often at night than they did during the day, and in areas of moderate background sound levels. Our results support the idea that pauses during mastication represent a form auditory vigilance that is responsive to landscape variables. Furthermore, these results suggest that exploring this behavior is critical to understanding an animal's perception of risk and the costs associated with vigilance behavior.