Life Sciences Commons^™

The Relationship Between Predation Pressure, Demography And Genetic Diversity In Song Sparrow (Melospiza Melodia) Populations, Michelle E. Bondy

Electronic Thesis and Dissertation Repository

While the impacts of predators on prey demography are well studied, relatively few studies have explored how predators affect the population genetics of prey. I investigated the effects of predation pressure on genetic diversity and genetic similarity in song sparrows (Melospiza melodia) and the demographic mechanisms (births, deaths and dispersal) that may drive this relationship. I compared genetic diversity and genetic similarity (measured at 13 neutral microsatellite loci) between landscapes (island and mainland), and between populations within each landscape. In every comparison, sparrows inhabiting the landscape or population with higher nest predation were more related to one another, and …

Metals And Persistent Organic Pollutants As Ecological Determinants Of Human Health In Naivasha, Kenya, Chelsea R. Hicks

Electronic Thesis and Dissertation Repository

The main industries in Naivasha are floriculture and geothermal energy, with both industries beginning in the 1980s. Increased employment caused a 20-fold increase in population over 3 decades. These changes have the potential to increase the release of environmental contaminants, such as metals and persistent organic pollutants (POPs). This study uses an ecosystem health approach to study the distribution and health risks associated with metals in airborne dust and POPs and metals in Cyprinus carpio dorsal muscle, in Naivasha, Kenya. Findings suggest that Ni in airborne dust may be derived from natural catchment substrate, but still exists at concentrations above …

How Does Gene Flow Limit Local Adaptation At A Species Range-Edge? An Artificial Selection Drosophila Model, Justin P. Saindon

Electronic Thesis and Dissertation Repository

Gene flow has the potential to create species range limits by impeding adaptation to selective pressures at the range-edge, but it is unclear whether there is a threshold level of gene flow that causes this effect. This gene swamping hypothesis was tested using laboratory populations of Drosophila melanogasterunder selection for desiccation resistance, and subject to a gradient of migration from unselected populations. Desiccation tolerance was impeded across the entire migration gradient, and populations receiving intermediate levels of migration exhibited no tolerance for desiccation stress, following twelve selection events. Female, but not male, flies increased desiccation tolerance following selection by …

Dynamics Of Fat And Lean Mass In Refuelling Migrant Passerines Measured Using Quantitative Magnetic Resonance, Lisa V. Kennedy

Electronic Thesis and Dissertation Repository

Although fat deposition during stopover in migrating passerine birds has been extensively studied, changes in lean mass during refuelling are not well understood. I used quantitative magnetic resonance (QMR) analysis to measure the deposition of fat and lean mass for both recaptured and single capture migrant passerines in spring and fall at Long Point, Ontario. Both the recapture analysis and single capture regression analysis indicated a substantial contribution of lean mass to overall increases in total body mass. Some of the variation in the relative deposition of fat and lean mass was explained by sex, age and season. I then …

Bats And The Landscape: The Influence Of Edge Effects And Forest Cover On Bat Activity, Meredith K. Jantzen

Electronic Thesis and Dissertation Repository

The habitats in which bat species may most effectively forage are often determined by species-specific differences in wing morphology and echolocation call structure. Habitat edges are important for bat navigation and foraging, but no study to date has examined the depth of edge influence (DEI--the extent of quantifiable change in activity with distance from an edge) for bats. I predicted that DEI would vary with species-specific differences in wing structure and echolocation call characteristics. Additionally, because different habitats may be required to fulfill species’ foraging and roost requirements, I predicted that bat activity would be highest in areas with a …

Physiological Ecology Of Bat Migration, Liam P. Mcguire

Electronic Thesis and Dissertation Repository

Migration is perhaps the most poorly understood aspect of bat biology and the underlying physiological basis is virtually unstudied. Although distantly related, bats and birds are both endothermic flying vertebrates and bird migration physiology has been studied for decades. Therefore, I used migratory birds as a model system to make predictions regarding the physiological ecology of bat migration.

First, I compared brain size of migratory and sedentary bat species. Migratory species have smaller brains which suggests the costs of carrying and maintaining a large brain are incompatible with the demands of migration. Next, I studied silver-haired bats (Lasionycteris noctivagans …

Effects Of Exogenous Androgens On Parental Care Behaviour In Male Bluegill Sunfish (Lepomis Macrochirus), Chandra M.C. Rodgers

Electronic Thesis and Dissertation Repository

Research suggests an androgen mediated trade-off between nurturing and defensive behaviour during parental care. This research, however, comes from species with biparental care, where changes in behaviour of one parent can be compensated for by the other parent. I tested the validity of this trade-off by manipulating androgen levels in bluegill sunfish (Lepomis macrochirus), a species where males provide sole parental care. I implanted males with testosterone, 11-ketotestosterone or flutamide, an androgen receptor blocker, and tested their nurturing behaviour and aggressiveness towards a brood predator. Males implanted with 11-ketotestosterone were 64% more aggressive and 71% less nurturing than …

Introduced Chinook Salmon (Oncorhynchus Tshawytscha) In Lake Huron: Do They Spawn At The Right Time?, Meghan T. Gerson

Electronic Thesis and Dissertation Repository

Chinook salmon (Oncorhynchus tshawytscha), following their introduction to the Great Lakes, have successfully colonized many tributaries. Under the hypothesis that colonization success is facilitated by intrinsic factors (i.e., preadaptation), I predicted that patterns of reproductive timing in an introduced population would show similarities with those in their native range. To test this prediction, attributes of reproductive timing were characterized in Chinook salmon from the Sydenham River, Ontario. In their native range, female Chinook salmon exhibit a seasonal decline in reproductive lifespan, a decline in fat stores, low egg retention at death (< 0.5%), and spawning at temperatures below 12.8°C. In contrast, Sydenham River Chinook salmon showed no seasonal decline in reproductive lifespan or fat stores and nineteen of twenty females had egg retention greater or equal to 0.5%. Also, many individuals (30%) spawned when water temperatures exceeded 12.8°C. Thus, individuals do not appear to be pre-adapted in this system.

Trace Metal Limitation And Its Role In Oxidative Stress Of Coral Algal Symbionts; Implications For Thermally Induced Coral Bleaching Events., Katrina Lynn Iglic

Electronic Thesis and Dissertation Repository

Coral bleaching, the process in which corals expel their photosynthetic symbionts (Genus Symbiodinium), is caused by high temperature and irradiance stress. The synergistic effect of each stressor is the generation of damaging reactive oxygen and nitrogen species (ROS and RNS), which are normally mitigated physiologically by antioxidant enzyme activity. Antioxidant enzymes require iron, copper, manganese and zinc in their structure and the limited nature of these trace metals in reef environments may enhance ROS production under elevated temperature and irradiance. The hypothesis tested within this thesis was that a limited availability of the trace metals Fe, Mn, Cu and …

A Model System In Landscape Genetics – The Insect Inhabitants Of Pitcher Plants, Gordana Gojko Rasic

Electronic Thesis and Dissertation Repository

Landscape genetics is a rapidly growing field that investigates how landscape and environmental features interact with microevolutionary processes to give rise to spatial genetic variation in populations. The ability to predict landscape effects on genetic patterns has been limited by the lack of studies conducted on more than one species, over multiple spatial scales and in replicated landscapes. A system that allows for such studies are the insect inhabitants of the purple pitcher plant (Sarracenia purpurea): the pitcher plant flesh fly (Fletcherimyia fletcheri), the midge (Metriocnemus knabi) and the mosquito (Wyeomyia smithii). In this thesis, I worked towards developing this …

Extent, Characteristics And Downstream Effects Of Stream Enclosure In Southwestern Ontario, Katie L. Stammler

Electronic Thesis and Dissertation Repository

In a 16000 km² area of southwestern Ontario, almost 15% of all streams have been enclosed (buried) largely for agricultural purposes. ArcGIS was used to characterize the natural features of catchments and to calculate enclosedness (proportion of stream network enclosed; x̅ = 16.5%, n = 10106). Catchments with the highest enclosedness received >990 mm of precipitation annually and had high drainage density (>1.9 km/km²), while catchments with the lowest enclosedness receivedannually, were characterized by clay and undrumlinized till plains and had relatively shallow water tables (m). These natural features influence where enclosure is likely to occur, …

Stopover Biology Of Migratory Landbirds In A Heavily Urbanized Landscape, The New York Metropolitan Area, Chad L. Seewagen

Electronic Thesis and Dissertation Repository

Migration routes of many Nearctic-Neotropical landbirds pass through the most urbanized regions of North America. Migrants use urban habitat fragments as stopover sites and commonly occur in cities at exceptional density. Yet, knowledge of migrant stopover biology and refueling opportunities in such places is severely limited. This dissertation examined several aspects of migrant stopover biology in the New York metropolitan area to gain a more holistic understanding of how migratory landbirds utilize urban stopover sites, and ultimately to assess the quality of urban habitats as stopover sites. I first generated morphometric predictive models using salvaged bird specimens to allow me …