Ecology and Evolutionary Biology Commons^™

Investigating The Effects Of Disturbance And Competition On Establishment, Growth, And Reproduction Of The Endangered Ripariosida Hermaphrodita, Daniel Engelking

Theses and Dissertations (Comprehensive)

Ripariosida hermaphrodita (Virginia Mallow) is a perennial riparian plant with broad, maple-like leaves. It grows up to three meters high and is often found in large clonal patches, but sexually reproduces readily. While this plant may seem like a redoubtable competitor when growing in large colonies, it is declining across its range in North America. The only known occurrences in Canada are in southern Ontario. Prior to this study, no new populations had been recorded even though one of the known populations produces copious amounts of viable seed with potential to disperse. There are many hypotheses for its rarity, but …

Differences In Drifting Invertebrate Communities Across Arctic Ecozones And The Influence On Potential Growth Of Grayling (Thymallus Arcticus), Charles Chanyi

Theses and Dissertations (Comprehensive)

Invertebrate drift is a key process that potentially affects multiple levels of food web organization within stream environments. However, our understanding of the mechanistic drivers of drift in high latitude streams and subsequent bottom-up control that drift may have on fish predators in these environments remains understudied. This project aimed to gain the baseline knowledge of how drift functions across two major high latitude ecozones, the boreal forest and tundra, and how those possible differences in drifting community characteristics may impact drift-feeding Arctic grayling (Thymallus arcticus). These objectives were accomplished by characterizing stream environments across both ecozones, sampling …

Potential Effects Of Road Proximity On Zooplankton Communities And Water Quality In Lakes In The Northwest Territories, Marie N. Hannan

Theses and Dissertations (Comprehensive)

Studies conducted along Canada’s Dempster Highway in the Northwest Territories have shown that road dust can affect water quality in roadside lakes, leading to higher calcium, conductivity, and pH levels. These water quality changes have the potential to affect important members of the lower aquatic food web, such as zooplankton.

For my thesis research, I had two main objectives: 1) To determine if changes in water chemistry caused by deposition of road dust affects zooplankton communities; and 2) To examine if the type of roadside vegetation influences the effects of road dust on aquatic habitats. To achieve these objectives, I …

Design And Validation Of Artificial Feeders To Study Feeding Preferences And Growth Of Hematophagous Juvenile Sea Lamprey (Petromyzon Marinus), Gracie Li-Ting-Wai

Theses and Dissertations (Comprehensive)

The parasitic and invasive land-locked sea lamprey Petromyzon marinus populations contributed to the collapse of the Great Lakes fisheries in the mid-1900s, while native anadromous populations are currently under threat and require conservation efforts for protection. Despite the increasing concern for both populations of this species, the juvenile stage of the sea lamprey’s life cycle has not been well studied. This is due, in part, to ethical concerns raised around holding live host fish with juveniles and the lack of an alternative feeding method to maintain these juveniles in the laboratory. The feeder should be designed to minimize fouling of …

Arctic Stream Characteristics And Diet Analysis Choice Impact Condition And Diet Estimates Of Ninespine Stickleback (Pungitius Pungitius), Adam Kuhrt

Theses and Dissertations (Comprehensive)

Ninespine stickleback (Pungitius pungitius) are ubiquitous in circumpolar freshwaters, but their ecological role is not well understood. Little research has been conducted on the influence of environmental variables on ninespine stickleback in stream environments, and while they are understood to be generalist feeders, their diet in stream environments is equally understudied. Determining diet is difficult due to biases inherent in all standard diet analysis methods. Morphological gut-content analysis (M-GCA), DNA metabarcoding of gut contents (D-GCA), and stable isotope analysis (SIA) are currently three of the most frequently conducted diet analyses; and while combinations of these methods are commonly …

Impact Of Orthophosphate As A Corrosion Inhibitor And Chloramine Disinfectant On Drinking Water Biofilm Communities, Mitchell Cooke

Theses and Dissertations (Comprehensive)

A drinking water distribution system (DWDS) must maintain conditions within quality standards which assure the effective and safe transport of finished drinking water from treatment plants to the household tap. Although safe to drink, finished water is not sterile, and may contain hundreds of microorganisms in a single milliliter. These microorganisms are present from the source waters, such as lakes, rivers and aquifers, and have passed through early treatment steps. Final treatment steps, such as the maintenance of disinfectant residuals, are used to further minimize viable cells present and focus on the reduction of harmful organisms. Microbial cells entering the …

Impacts Of Changing Permafrost Conditions On Vegetation Productivity In The Northern Boreal Forest, Emily Ogden

Theses and Dissertations (Comprehensive)

Vegetation productivity across the boreal forest has increased over the past several decades. However, at a regional scale there is large variation from increased (greening) to decreased (browning) productivity and large areas with no measured change. Some of this variation can be explained by disturbances, such as wildfire, or by increased climate variability. In northern regions underlain by permafrost, the interactions between climate, disturbance, and vegetation productivity may be more complex. For my thesis, I used a time-series of ground thermal data from permafrost monitoring sites established by the Geological Survey of Canada along a latitudinal transect of the Northwest …

Can Zooplankton On The North American Great Plains ‘Keep Up’ With Climate-Driven Salinity Change?, Mariam Elmarsafy

Theses and Dissertations (Comprehensive)

The Great Plains of North America are projected to become more arid as the climate changes over the next century. Salinity levels for lakes in this region are linked to climate, suggesting that lakes will become more saline as the climate becomes drier. One group of organisms that might be affected by increased salinity levels are the zooplankton, aquatic invertebrates that transfer energy from primary producers to macroinvertebrates and fish. Little is known about the ability of zooplankton to adapt to long-term increases in lake salinity levels. For my thesis, I used resurrection ecology to examine how a common zooplankter, …

Impacts Of Transportation Infrastructure On Water Quality, Sediment Loads, And Fishing Opportunities In The Gwich’In Settlement Area, Northwest Territories, Matthew Teillet

Theses and Dissertations (Comprehensive)

The addition of gravel sediment to build ferry landings on the Peel and Mackenzie Rivers has been an ongoing concern for the Gwich’in communities of Fort McPherson and Tsiigehtchic that depend on the rivers for their livelihoods. Specifically, there are concerns that gravel from ferry landings is degrading water quality, harming fishing opportunities, and altering river morphology downstream. Previous reports concluded that ferry operations were not impacting downstream ecology. However, past studies had methodological shortcomings and community concerns about the ferry landings remain. To study the impact of the gravel landings on water quality, I utilized a multidisciplinary study design …

Abiotic Conditions, Algal Biomass & Fish Growth Rates Affect Fish Mercury Concentrations In Two Subarctic Lakes, Ari Yamaguchi

Theses and Dissertations (Comprehensive)

Kakisa Lake and Tathlina Lake, located in the Dehcho Region of the Northwest Territories, support important fisheries for the local Ka’a’gee Tu First Nation (KTFN). Recently, Walleye (Sander vitreus) of typical catch size in Tathlina Lake were found to have mercury concentrations above Health Canada’s commercial sale guideline of 0.5 ppm. Wild foods with elevated mercury concentrations can pose health risks to the humans who consume them, depending on consumption amounts and vulnerability factors such as age and pregnancy. Because wild fish can accumulate relatively high mercury levels and subsistence fishing contributes greatly to food security in northern …

Happy Or Hangry Families: Does Kinship Mediate Cooperation And Cannibalism In Drosophila Melanogaster Larvae?, Lucas Khodaei

Theses and Dissertations (Comprehensive)

The fruit fly Drosophila melanogaster has a long history as a research model for studies on behaviour and group dynamics. When individuals are grouped in an environment and resources decrease, then they may behave co-operatively with one another or antagonistically compete. Hamilton’s Law states that if the benefit of helping a related individual out-weighs the cost to its direct fitness, then the individual’s indirect fitness will increase when they help their kin compared to helping an unrelated stranger. Yet it is unknown whether kinship mediates larval behaviour to encourage co-operation and/or lessen antagonistic behaviours between consanguineous individuals. In this thesis …

Competition Or Facilitation: Examination Of Interactions Between Endangered Sida Hermaphrodita And Invasive Phragmites Australis, Samantha N. Mulholland

Theses and Dissertations (Comprehensive)

Virginia Mallow (Sida hermaphrodita) is a perennial herb of the Malvaceae family that is native to riparian habitats in northeastern North America. Throughout most of its geographical distribution however, it is considered threatened and only two populations are known from Canada. The biology and ecology of S. hermaphrodita are still poorly understood and although few studies have been performed to determine the factors that contribute to the species rarity, it is considered threatened potentially due to the loss of habitat caused by exotic European Common reed (Phragmites australis subsp. australis) invasion. Allelopathic and phytotoxic conditioning of …

Factors Influencing Zooplankton Communities In Small Arctic Lakes, Northwest Territories, Jasmina Vucic

Theses and Dissertations (Comprehensive)

The Canadian Arctic has been warming at an unprecedented rate, causing significant changes to the environment. At the same time, continued development in the north has increased the demand for gravel extraction used to construct and maintain infrastructure such as highways. The development of roadways and gradual loss of permafrost in Canada’s north has led to changes in water quality, including increased calcium, conductivity, and nutrients. In addition, gravel extraction has led to the formation of artificial gravel pit lakes. Research has yet to determine how physical and chemical changes associated with development and permafrost thaw might impact zooplankton, and …

Near-Surface Permafrost Ground Ice Characteristics And Ecological And Physical Drivers Of Transient Layer Ice Content In Discontinuous Permafrost, Jason Paul

Theses and Dissertations (Comprehensive)

Accelerated climate warming in northern regions is causing permafrost degradation, leading to the reduction of the areal extent of permafrost. Permafrost is the foundation for many northern ecosystems and communities, so its thaw can have important ecological and societal consequences. Thaw of ice-rich permafrost can cause subsidence of the ground surface proportional to excess ice content. Terrain settlement can cause ponding or damage to infrastructure. Following a surface disturbance that removes much of the vegetation cover, a shift in the ground thermal regime can cause an increase in active layer thickness and rapid thaw of the top portion of permafrost. …

Relationships Between Factors Influencing Biofilm Formation And Pathogen Retention In Complex Rhizosphere Microbial Communities, Aaron Coristine

Theses and Dissertations (Comprehensive)

Riparian wetlands are unique habitats facilitating all forms of life. The riverbanks of these environments provide ideal conditions for bacteria, plants, and higher organisms. Of particular interest to this research was the variation in microbial community structure at high, intermediate and poor water quality impacted areas. Assessing the capabilities of plants to retain microbial pathogens was identified. Root systems and corresponding soil are ideal locations for bacterial deposition, resulting in attachment at these areas. Biofilm production in these regions is important for long-term establishment, leading to persistence and potential naturalization. Opportunistic pathogens originating from mammalian fecal matter are introduced into …

Influence Of Topography And Moisture And Nutrient Availability On Green Alder Function On The Low Arctic Tundra, Nt, Katherine Louise Black Ms., Jennifer Lynn Baltzer Dr.

Theses and Dissertations (Comprehensive)

The Arctic has warmed by at least 3^°C over the past 50 years and this rapid warming is expected to continue. Climate warming is driving the proliferation of shrubs across the tundra biome with implications for energy balance, climate, hydrology, nutrient cycling, and biodiversity. Changes in tundra plant water use attributable to shrub expansion are predicted to increase evapotranspirative water loss which may amplify local warming and reduce run-off. However, little is known about the extent to which shrubs will enhance evapotranspirative water loss in these systems. Direct measures of shrub water use are needed to accurately predict …

Quantifying Relationships Between Phosphorus Availability And Mycorrhizal Associations In Wetland Plants, Daniel Marshall

Theses and Dissertations (Comprehensive)

Increasing evidence indicates that plant community structure and therefore ecosystem function are mediated by below-ground fungal communities that form intracellular associations with plant roots called mycorrhizal associations. Arbuscular mycorrhizal fungi (AMF) are a type of mycorrhiza that colonize the plant host intracellularly but maintain hyphae outside the root cell for resource acquisition. The importance and function of AMF associations are well-documented in terrestrial ecosystems, but are less understood in aquatic or semi-aquatic systems. Phosphorus availability is the primary factor influencing mycorrhizal colonization and growth in terrestrial soils, with phosphorus-abundant soils leading to a decrease in mycorrhizal growth. However, the relationship …

An Assessment Of How Plant And Mycorrhizal Communities Have Been Affected Along A Mine-Impacted Watershed In The Northwest Territories, Kevin Maccoll

Theses and Dissertations (Comprehensive)

Giant Mine is an inactive gold mine located nine kilometers north of Yellowknife, Northwest Territories. Giant Mine has been the source of arsenic trioxide for the Baker Creek watershed since it opened over 60 years ago. Although arsenic levels in the creek are above the limits considered to be biologically relevant, there is no concrete evidence that plants and mycorrhizae have actually been affected. This study provides an initial assessment of the impacts mining activity at Giant Mine has had on plants and mycorrhizae in the Baker Creek watershed. Nine sites were sampled around Giant Mine: five sites downstream from …

Mate Choice And Consequences For Consanguineous Mating In Drosophila Melanogaster, Emily S. Martin

Theses and Dissertations (Comprehensive)

The ability to discriminate between prospective mates is potentially important not only for the avoidance of unsuccessful or incompatible matings, but also for the selection of higher “quality” mates. Inbreeding, reproduction between closely related individuals, has long enjoyed the attention of biologists, and has classically been associated with fitness consequences that are primarily negative, termed “inbreeding depression”. Indeed, the costs of mating with a relative are well documented across a wide variety of species. If individuals are capable of kin recognition, it is expected that species should evolve to avoid consanguineous matings. However, a number of recent models suggest circumstances …