Year: 2024, 2024
Member of: Trent University Graduate Thesis Collection
Name(s): Creator (cre): Miller, Hannah, Thesis advisor (ths): Murray, Dennis L, Degree committee member (dgc): Schaefer, Jim, Degree committee member (dgc): Burness, Gary, Degree committee member (dgc): Raby, Graham, Degree granting institution (dgg): Trent University Abstract: <p>I tracked summer movements and activity of snowshoe hares (Lepus americanus) in southwestern Yukon, Canada, during their population cycle (2015–2022) to assess the primary drivers of movement. Hares exhibited variable movement and activity during the cycle, exhibiting increased home range size and higher daily displacement during low population densities. Males exhibited more dramatic… more Year: 2021, 2021
Member of: Trent University Graduate Thesis Collection
Abstract: <p>Anthropogenic activities such as human activity and livestock grazing are responsible for the global rise in disturbance impacts on wildlife and may underlie regional changes in biodiversity and ecosystem dynamics. Few studies have tried to disentangle the effects of different anthropogenic activities on wildlife behaviour, leaving a major gap in our understanding of conservation and… more Year: 2019, 2019
Member of: Trent University Graduate Thesis Collection
Abstract: <p>The purpose of this thesis is to quantify the habitat characteristics, density patterns and environmental niches of two groups of Indo-Pacific humpback dolphins: Chinese white dolphins (CWD) of the Pearl River estuary (PRE), and Taiwanese white dolphins (TWD, =Taiwanese humpback dolphin, THD) found in the eastern Taiwan Strait (ETS). Much work has already been done on the habitat use of… more Year: 2019, 2019
Member of: Trent University Graduate Thesis Collection
Abstract: <p>Wild populations are notoriously difficult to study due to confounding stochastic variables. This thesis tackles two components of investigating wild populations. The first examines the use of niche modeling to quantify macro-scale predator-prey relationships in canid populations across eastern North America, while the second examines range-wide molecular structure in Canada lynx. The… more Year: 2019, 2019
Member of: Trent University Graduate Thesis Collection
Abstract: <p>Populations have long been delineated by physical barriers that appear to limit reproduction, yet increasingly genetic analysis reveal these delineations to be inaccurate. The eastern and mid-continent populations of sandhill cranes are expanding ranges which is leading to convergence and warrants investigation of the genetic structure between the two populations. Obtaining blood or… more Year: 2019, 2019
Member of: Trent University Graduate Thesis Collection
Abstract: <p>Predation risk can elicit a range of responses in prey, but to date little is known about breadth of potential responses that may arise under realistic field conditions and how such responses are linked, leaving a fragmented picture of risk-related consequences on individuals. We increased predation risk in free-ranging snowshoe hares (Lepus americanus) during two consecutive summers by… more Year: 2018, 2018
Member of: Trent University Graduate Thesis Collection
Abstract: <p>Numerous prey taxa employ defensive postures for protection against attack by predators. Defensive postures mitigate predation risk at various stages of the predator-prey sequence, including through crypsis, mimicry, thanatosis, aposematism, and deflection. In terrestrial salamanders, defensive postures may be aposematic, or deflect attacks away from vital body parts and towards the tail… more Year: 2018, 2018
Member of: Trent University Graduate Thesis Collection
Abstract: <p>Salamanders are capable of tissue regeneration throughout all life-stages, which requires the dedifferentiation of mature cells to regrow lost tissues. Dedifferentiation is promoted by degradation of the extracellular matrix by matrix metalloproteases, as well as lysosomal degradation of intracellular and cell-surface proteins that mark cells as part of a mature lineage. Salamanders are… more Year: 2018, 2018
Member of: Trent University Graduate Thesis Collection
Abstract: <p>To better understand species' resilience to climate change and implement solutions, we must conserve environments that maintain standing adaptive genetic variation and the potential generation of new beneficial alleles. Coding trinucleotide repeats (cTNRs) providing high-pace adaptive capabilities via high rates of mutation are ideal targets for mitigating the decline of species at… more Year: 2018, 2018
Member of: Trent University Graduate Thesis Collection
Abstract: <p>While both resource quality and predator-derived chemical cues can each have profound effects on zooplankton populations and their function in ecosystems, the strength and nature of their interactive effects remain unclear. We conducted laboratory experiments to evaluate how stoichiometric food quality (i.e., algal carbon (C):phosphorus (P) ratios) affects responses of the water flea,… more Year: 2017, 2017
Member of: Trent University Graduate Thesis Collection
Abstract: <p>The predator vs. prey dynamic is an omnipresent factor in ecological systems that may drive changes in life history patterns in prey animals through behavioural, morphological, and physiological changes. Predation risk can have profound effects on the life history events of an animal, and is influenced by the neuroendocrine stress response. Activation of the hypothalamic-pituitary-… more Year: 2017, 2017
Member of: Trent University Graduate Thesis Collection
Abstract: <p>Population cycles are regular fluctuations in population densities, however, in recent years many cycles have begun to disappear. With Canada lynx this dampening has also been seen with decreasing latitude corresponding to an increase in prey diversity. My study investigates the role of alternate prey on the stability of the lynx-hare cycle by first comparing the functional responses of… more Year: 2017, 2017
Member of: Trent University Graduate Thesis Collection
Abstract: <p>Mountain ranges are often thought to restrict movement of wildlife, yet previous studies evaluating the role of the Rocky Mountains as a dispersal barrier for Canada lynx (Lynx canadensis) have been contradictory. Our study uses neutral microsatellite loci to evaluate the role of the Rocky Mountains as a barrier to gene flow for lynx. Although lynx exhibited low genetic differentiation,… more Year: 2017, 2017
Member of: Trent University Graduate Thesis Collection
Abstract: <p>Chemical cues are used commonly by prey to identify predation risk in aquatic environments. Previous work has indicated that negatively-charged ions of m/z 501 are possibly a kairomone that induces anti-predator responses in tadpoles. This thesis found that this ion species: (i) is produced by injured tadpoles; (ii) exhibits increased spectral intensity with higher tadpole biomass; and (… more Year: 2015, 2015
Member of: Trent University Graduate Thesis Collection
Abstract: <p>The objective of this thesis is to better understand the demography and habitat selection of Newfoundland caribou. Chapter 1 provides a general introduction of elements of population ecology and behavioural ecology discussed in the thesis. In Chapter 2, I examine the causes of long-term fluctuations among caribou herds. My findings indicate that winter severity and density-dependent… more Year: 2015, 2015
Member of: Trent University Graduate Thesis Collection
Abstract: <p>Population density regulation is a fundamental principle in ecology, however there remain several unknowns regarding the functional expression of density dependence. One prominent view is that the patterns by which density dependence is expressed are largely fixed across a species, irrespective of environmental conditions. Our study investigated the expression of density dependence in… more Year: 2015, 2015
Member of: Trent University Graduate Thesis Collection
Abstract: <p>Climate change has had numerous impacts on species' distributions by shifting suitable habitat to higher latitudes and elevations. These shifts pose new challenges to biodiversity management, in particular translocations, where suitable habitat is considered crucial for the reintroduced population. De-extinction is a new conservation tool, similar to reintroduction, except that the… more Year: 2015, 2015
Member of: Trent University Graduate Thesis Collection
Abstract: <p>My objective was to understand how individual variation, in conjunction with variation in habitat, can affect individual and population-level variation in animal space use. I used coyotes (Canis latrans) as a model species to investigate the roles of hybridization, an inherited intrinsic factor, and spatial memory, a learned intrinsic factor, on space use. I used a diversity of methods… more Year: 2014, 2014
Member of: Trent University Graduate Thesis Collection
Name(s): Creator (cre): Bennett, Amanda Maria, Thesis advisor (ths): Murray, Dennis L, Degree committee member (dgc): Burness, Gary, Degree committee member (dgc): Kerr, Leslie, Degree committee member (dgc): Ridgway, Mark, Degree granting institution (dgg): Trent University Abstract: <p>Inducible defenses are plastic responses by an organism to the perception of predation risk. This dissertation focuses on three experiments designed to test the hypothesis that plastic ability is limited by energetic constraints. Chapter 1 provides a general introduction to phenotypic plasticity research and the theoretical costs and limitations affecting the expression of plastic traits… more
