Graduate Theses & Dissertations

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Comparing Two Tablet-Based Visuomotor Tasks to Standard Laboratory Versions
The assessment of visuomotor function can provide important information about neurological status. Several visuomotor tasks exist for testing in the laboratory, although attempts to make these tests portable to allow quick and reliable assessment have been limited. We developed an assessment tool using two laboratory visuomotor tests as a tablet application: the double-step task, and an interception task. Performance was assessed by measuring the participants’ ability to reach toward unpredictably moving targets in each task. Response patterns were compared across equipment types to determine if participants were responding similarly to the moving targets in the standard laboratory and the tablet version of the tasks. On the double-step task, participants adjusted to the displaced target adequately in both the lab and tablet versions. On the interception task, participants intercepted non-accelerating targets, and performed worse on accelerating targets in both versions of the task. These findings suggest that the tablet version of these tasks assesses similar visuomotor processing as the respective laboratory version. Author Keywords: concussion assessment, double-step task, interception task, visuomotor processing, visuomotor system
Comparing Biological Responses to Contaminants in Darters (Etheostoma spp.) Collected from Rural and Urban Regions of the Grand River Watershed, Ontario
Urban and agricultural activities may introduce chemical stressors, including contaminants of emerging concern (CECs) and current use pesticides (CUPs) into riverine systems. The objective of this study was to determine if fish collected from sites in a river show biomarkers of exposure to these classes of contaminants, and if the biomarker patterns vary in fish collected from urbanized and agricultural sites. The watershed selected for this study was the Grand River in southern Ontario, which transitions from areas dominated by agricultural land use in the north to highly urbanized locations in the southern part of the watershed. Rainbow darters (Etheostoma caerluem) and fantail darters (Etheostoma flabellare) were collected from the Grand River in June, 2014 for biomarker analysis from two urbanized sites and three agricultural sites (n=20 per site). Over the same period of time, Polar Organic Chemical Integrative Samplers (POCIS) were deployed for 2 weeks at each site to monitor for the presence of CUPs and CECs. The amounts of the target compounds accumulated on POCIS, determined using LC-MS/MS were used to estimate the time weighted average concentrations of the contaminants at each site. Data on the liver somatic index for darters indicate site-specific differences in this condition factor (p<0.05). Significant differences in the concentrations of thiobarbituric acid reactive substances (TBARS) in gill tissue (p<0.05) indicate differences in oxidative stress in fish collected from the various sites. Measured concentrations of ethoxyresorufin-O-deethylase (EROD) in liver tissue were significantly different between sites (p<0.05), indicating differences in CYP1A metabolic activity. Finally, acetylcholinesterase (AChE) activity in brain tissue was significantly different between fish from rural and urban sites (p<0.05). The analysis of these biomarkers indicates that fish may be experiencing different levels of biological stress related to different land uses. These data may be useful in developing mitigation strategies to reduce impacts on fish and other aquatic organisms in the watershed. Author Keywords: AChE, Biomarker, Darter, EROD, POCIS, TBARS
Comparative phylogeography in conservation biology
Phylogeographic histories of taxa around the Great Lakes region in North America are relevant to a range of ongoing issues including conservation management and biological invasions. In this thesis I investigated the comparative phylogeographic histories of plant species with disjunct distributions and plant species with continuous distributions around the Great Lakes region; this is a very dynamic geographic area with relatively recent colonisation histories that have been influenced by a range of factors including postglacial landscape modifications, and more recently, human-mediated dispersion. I first characterized four species that have disjunct populations in the Great Lakes region: (Bartonia paniculata subsp. paniculata, Empetrum nigrum, Sporobolus heterolepis, and Carex richardsonii). Through comparisons of core and disjunct populations, I found that a range of historical processes have resulted in two broad scenarios: in the first scenario, genetically distinct disjunct and core populations diverged prior to the last glacial cycle, and in the second scenario more recent vicariant events have resulted in genetically similar core and disjunct populations. The former scenario has important implications for conservation management. I then characterized the Typha species complex (T. latifolia, T. angustifolia, T. x glauca), which collectively represent species with continuous distributions. Recent microevolutionary processes, including hybridization, introgression, and intercontinental dispersal, obscure the phylogeographic patterns and complicate the evolutionary history of Typha spp. around the Great Lakes region, and have resulted in the growing dominance of non-native lineages. A broader geographical comparison of Typha spp. lineages from around the world identified repeated cryptic dispersal and long-distant movement as important phylogeographic influences. This research has demonstrated that comparisons of regional and global evolutionary histories can provide insight into historical and contemporary processes useful for management decisions in conservation biology and invasive species. Author Keywords: chloroplast DNA, conservation genetics, disjunct populations, invasive species, phylogeography, postglacial recolonisation
Comparative efficacy of eDNA and conventional methods for monitoring wetland anuran communities
Identifying population declines and mitigating biodiversity loss require reliable monitoring techniques, but complex life histories and cryptic characteristics of anuran species render conventional monitoring challenging and ineffective. Environmental DNA (eDNA) detection is a highly sensitive and minimally invasive alternative to conventional anuran monitoring. In this study, I conducted a field experiment in 30 natural wetlands to compare efficacy of eDNA detection via qPCR to three conventional methods (visual encounter, breeding call, and larval dipnet surveys) for nine anuran species. eDNA and visual encounter surveys detected the greatest species richness, with eDNA methods requiring the fewest sampling events. However, community composition results differed among methods, indicating that even top performing methods missed species detections. Overall, the most effective detection method varied by species, with some species requiring two to three methods to make all possible detections. Further, eDNA detection rates varied by sampling season for two species (A. americanus and H. versicolor), suggesting that species-specific ecology such as breeding and larval periods play an important role in eDNA presence. These findings suggest that optimized monitoring of complex anuran communities may require two or more monitoring methods selected based on the physiology and biology of all target species. Author Keywords: amphibian, anuran, conventional monitoring, eDNA, environmental DNA, species richness
Comparative Studies in Tropical Epicentres in Southeast Asia
From ca. 800-1400 CE, low-density agrarian states dominated Southeast Asia, their authority emanating from their epicentres at places such as Angkor in Cambodia, Bagan in Myanmar, and Sukhothai in Thailand. These epicentres were the setting for numerous structures, activities, and stakeholders that became integral for the perpetuation of the state. These states and their epicentres declined and collapsed around the same time. As part of a larger project (the Socio-ecological Entanglement in Tropical Societies (SETS Project), the aim of this thesis is to add to our understanding of entanglement, resilience, and collapse in Southeast Asia. Using a relatively new method that combines resilience and entanglement theories, this thesis presents a view of epicentral entanglements and vulnerabilities that eventually contributed to the collapse of these societies. The results indicate that overextended socio-ecological systems and their growing entanglements created a loss of resilience and, when faced with change in these systems, collapse. Author Keywords: Angkor, Bagan, Entanglement Theory, Resilience Theory, Southeast Asia, Sukhothai
Comparative Evaluation of Effective Population Size Genetic Estimation Methods in Wild Brook Trout (Salvelinus fontinalis) Populations
Effective population size (Ne) is a key concept in population genetics, evolutionary biology and conservation biology that describes an important facet of genetic diversity and the capacity of populations to respond to future evolutionary pressures. The importance of Ne in management and conservation of wild populations encouraged the development of numerous genetic estimators which rely on a variety of methods. Despite the number and diversity of available Ne methods, however, tests of estimator performance have largely relied on simulations, with relatively few tests based on empirical data. I used well-studied wild populations of brook trout (Salvelinus fontinalis) in Algonquin Park, Ontario as a model system to assess the comparative performance of multiple Ne estimation methods and programs, comparing the resultant Ne estimates against demographic population size estimates. As a first step, the genetic diversity and ancestry of wild brook trout populations was determined using 14 microsatellite loci. Genetic structure of brook trout populations showed variable contributions from historical supplemental stocking and also identified localized gene pools within and between watersheds, reflecting variable levels of connectivity and gene flow. Once the genetic ancestry and connectivity of populations had been resolved, single sample (point) and two samples (temporal) genetic estimators were used to estimate Ne of populations with pure native ancestry. Values obtained from genetic estimators utilizing both methods were variable within as well as among populations. Single sample (point) estimators were variable within individual populations, but substantially less than was observed among the temporal methods. The ratios of Ne to the estimated demographic population size (N) in small populations were substantially higher than in larger populations. Variation among estimates obtained from the different methods reflects varying assumptions that underlay the estimation algorithms. This research further investigated the effect of sampling effort and number of microsatellite loci used on Ne values obtained using the linkage disequilibrium (LD) estimation method. Ne estimates varied substantially among values generated from subsets of loci and genotyped individuals, highlighting the necessity for proper sampling design for efforts aiming to measure Ne. Despite the variation observed among and within estimation methods, the Ne concept is a valuable for the conservation and management of both exploited and endangered species. Author Keywords: Brook Trout, Effective population size, Genetic Diversity, Genetic Structure
Community, Complexity, and Collapse
The city-state of Minanha, located in west central Belize, reached its zenith and most culturally complex stage by the Late Classic period, 675-810 AD. Only a century later, its royal court “collapsed”. The Contreras Valley is a small farming community located in a settlement zone south of Minanha. Decades of research at Minanha and the analysis of artifact frequencies from commoner households allow for a better understanding of the intra- and inter-community social practices occurring at the site of Contreras Valley and within the greater Minanha area. An Archaeology of Communities as well as Resilience Theory frameworks are utilized to explore the integrative social, political, and economic strategies of this commoner population. These theories are used to better understand the developmental history of the royal court from the perspective of the peripheral commoners, who sustained a population while the royal court disintegrated. Furthermore, this thesis focuses on the intersection of resilience and communities, and how the Contreras Valley experienced phases of resilience as well as vulnerability throughout its history. The resilience of this group of individuals will generate an increased cognizance of how a community copes with and continues to thrive in a climate of political chaos and instability. Author Keywords: Ancient Maya, Archaeology, Archaeology of Communities, Artifact frequencies, Resilience Theory, Settlement pattern studies
Community and conservation
Faced with the intersecting environmental crises of the 21st century, conservation organizations are searching for practices that produce better, more sustainable outcomes. However, they have often relied on forms of conservation which shore up rather than disrupt settler relationships to land in the form of fortress conservation and assumptions about the human-nature dualism. In this thesis, I examine a local land trust that intends to include community[-based] conservation into its conservation practices. In particular, I explore how the organization’s volunteers understand and construct the relationship between community and conservation, and the ways this might impact operations. Using a community-based research approach, interviews (n=17) were conducted. The findings indicate that the volunteers are demographically homogenous, leading to a homogenous, Western-science informed understanding of community[-based] conservation. This perspective views involvement of community as a direct trade-off with optimal ecological goals. As the volunteers wield uncommon power in organizational governance, difference in opinions toward missions or operations could lead to constraints on the organization. This study contributes to larger academic discourses on environmental volunteers, land trusts, and frames of conservation, and provides tangible recommendations to an organization attempting to include community[-based] conservation in its practices. Author Keywords: community-based conservation, environmental governance, environmental volunteers, frames of conservation, land trusts, power
Community Coalescence and Regional Geospatial Trends of Ceramic Decorative Variation in Late Woodland Northern Iroquoia
This case study focuses on geospatial patterns of decorative variation in pottery assemblages from 234 Northern Iroquoian village communities, occupied between ca. 1350–1650 CE. Previous interpretations of these assemblages’ ceramic decorative variability have been based on the assertion that potters from these communities used collar decorative motifs as communicative social signals. However, they did not consider whether these geospatial decorative patterns could simply reflect the outcome of stochastic macroscale social learning processes driven solely by probabilistic information exchange between closer neighboring communities. Cultural transmission, the theoretical framework applied here, is well-suited to address this perspective. Thus, the primary research question of this case study is, “Are the expected outcomes of random copying processes sufficient to explain the range of geospatial ceramic decorative variability observed across Northern Iroquoia?” Random copying processes are the stochastic, probabilistic social learning mechanisms driving the collective decisions of multiple communities, making up one side of the “random-selective copying spectrum.” When the decorative decisions of multiple communities are collectively guided by shared ideas (such as, potentially, symbolic communication structures), they become subsumed under the broad umbrella of “selective copying” processes. The social learning mechanisms involved on both sides have predictable geospatial and structural ranges of ceramic decorative patterning. The goal of this case study was thus to evaluate the range of patterning in Northern Iroquoia, both generally as well as at narrower temporal and spatial scales. Ultimately, region-specific temporal trends in selective copying processes seeming to reflect recently established temporal trajectories of community coalescence were identified. Author Keywords: coalescence, cultural population structure, cultural transmission, isolation by distance, Northern Iroquoia, social signaling
Commonality of Enemies
Carlism and anarchism were revolutionary social movements that acquired significant popular support during the most intensive period of modernization in Spain (mid 19th to mid 20th centuries). It was noted but not well explored by contemporaries and historians that these enemies were similar in their hostility towards modernization and in their intense idealism. This thesis compares the two movements in order to determine the nature of their commonality and what this suggests about ideological enemies. A range of sources were consulted, including scholarship on modern Spain, biographical information on individuals who converted from Carlism to anarchism and contemporary print media. It was concluded that they were produced by the same destabilizing processes of disentailment and industrialization, which drew the working classes towards proposals that would have otherwise seemed implausibly utopian. The thesis further suggests that they were uniquely idealistic, in that they put moral integrity before the success of their cause. Author Keywords: anarchism, Carlism, enemy other, modernization, Modern Spain, social movements
Combining Line Transect Sampling and Photographic-Identification Surveys to Investigate the Abundance and Distribution of Cetaceans
Line transect sampling and photographic-identification (photo-ID) are common survey techniques for estimating the abundance and distribution of cetaceans. Combining these approaches in the field (‘combined LTPI’ surveys) and using data from both components has the potential for generating comprehensive ecological knowledge that can be far more valuable than when these techniques and their data are used independently. In this thesis, I evaluated the results and conclusions from these two methods, used singly and in tandem, by investigating the population dynamics of two humpback dolphin (Sousa chinensis spp.) populations: the large and widely distributed Chinese white dolphin (S. c. chinensis) of the Pearl River estuary (PRE), and the small and geographically isolated subspecies of Taiwanese white dolphin (S. c. taiwanensis) in the eastern Taiwan Strait. Data from combined LTPI surveys in Hong Kong waters, at the eastern edge of the PRE, revealed a shift in space use with individuals spending less time in these waters than at the start of surveys. Data from combined LTPI surveys in Taiwan provided further support for a subspecies restricted to the central western waters, and identified a commonly used area at the northern part of their limited range. These two case studies demonstrated an overall efficacy of combined LTPI surveys in ecological studies of cetaceans. However, a multi-criteria analysis revealed that combined LTPI surveys with a line transect focus (e.g., Hong Kong) performed better than a LTPI survey with a photo-ID focus (e.g., Taiwan) when considering ecological aspects of the study populations, labour and data requirements, and ecological output. Even so, the photo-ID focus of Taiwan’s monitoring program led to better assessments of individual space use patterns, likely helped by the Taiwanese white dolphin population’s smaller size and intensive photographic effort. In both cases, the ecological output of combined LTPI surveys could be improved by expanding the study area or extending the field season or frequency of surveys. Overall, I showed that by following a set of general guidelines, different iterations of the combined LTPI approach (i.e., photo-ID focus or LT focus) can serve as powerful tools for uncovering multi-dimensional ecological information on cetaceans. Author Keywords: abundance, cetacean, distribution, line transect sampling, multi-criteria analysis, Photo-ID
Combinatorial Collisions in Database Matching
Databases containing information such as location points, web searches and fi- nancial transactions are becoming the new normal as technology advances. Conse- quentially, searches and cross-referencing in big data are becoming a common prob- lem as computing and statistical analysis increasingly allow for the contents of such databases to be analyzed and dredged for data. Searches through big data are fre- quently done without a hypothesis formulated before hand, and as these databases grow and become more complex, the room for error also increases. Regardless of how these searches are framed, the data they collect may lead to false convictions. DNA databases may be of particular interest, since DNA is often viewed as significant evi- dence, however, such evidence is sometimes not interpreted in a proper manner in the court room. In this thesis, we present and validate a framework for investigating var- ious collisions within databases using Monte Carlo Simulations, with examples from DNA. We also discuss how DNA evidence may be wrongly portrayed in the court room, and the explanation behind this. We then outline the problem which may occur when numerous types of databases are searched for suspects, and framework to address these problems. Author Keywords: big data analysis, collisions, database searches, DNA databases, monte carlo simulation

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Format: 2023/06/09