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Articles 1 - 9 of 9
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Examining The Combined Impacts Of Rapid Senescence And A Low Water Stressor On Maternal State, Egg Quality, And Fitness In Chinook Salmon, Madison A. Sturba
Examining The Combined Impacts Of Rapid Senescence And A Low Water Stressor On Maternal State, Egg Quality, And Fitness In Chinook Salmon, Madison A. Sturba
Electronic Theses and Dissertations
Assessing the impact of environmental challenges on maternal state and breeding success is important for predicting how migratory Pacific salmon populations will respond to an increasingly stressful world. The overall goal of my thesis was to examine fine-scale senescent changes in female Chinook salmon over time, whether these changes impacted ovulation and egg quality, and whether exposure to an environmental challenge (low water) during senescence subsequently provoked even stronger state-dependent responses to ultimately impact female longevity and egg survival. Following an experimental decrease in water availability, I quantified changes in physical, physiological, and reproductive maternal state, then linked these changes …
Lower Trophic Relations Within The Lake Ontario Invertebrate Community As Assessed By Chemical Tracers, Donald Robert Uzarski
Lower Trophic Relations Within The Lake Ontario Invertebrate Community As Assessed By Chemical Tracers, Donald Robert Uzarski
Electronic Theses and Dissertations
The lower trophic food web of Lake Ontario plays an important role in the lake’s ecosystem, yet the trophic relationships of these taxa are not well understood. Utilizing carbon (δ13C) and nitrogen (δ15N) stable isotopes as a tool to trace the flow of energy through the system, the main objective of this thesis was to understand the isotopic variability and trophic relationships of invertebrate taxa through space and season in Lake Ontario. Using an extensive dataset collected in 2012 and 2013, this study was conducted in two research chapters. The first chapter assessed variation in the isotopic signature of three …
Does It Take A Community To Save A Species? Examining The Use Of Community Interactions To Restore Unionid Species At Risk, Roland Adriaan Eveleens
Does It Take A Community To Save A Species? Examining The Use Of Community Interactions To Restore Unionid Species At Risk, Roland Adriaan Eveleens
Electronic Theses and Dissertations
The conservation and restoration of freshwater ecosystems are complex. Knowledge from community ecology, conservation biology, and restoration ecology was integrated to interrogate the role of species interactions involving freshwater mussels (order Unionida) as keystone species. Freshwater mussels require host fish and provide ecosystem functions for other species throughout aquatic and riparian ecosystems, yet conservation efforts remain focused on focal mussel species or host fish associations. My thesis explored species co-occurrences within mussel and benthic macroinvertebrate community assemblages, and systematically reviewed the published literature to assess the breadth and reported effectiveness of mussel restoration. Community analyses confirmed species co-occurrences across environmental …
Parasites And Sexual Selection In A Sexually Dichromatic Toad, Nicole Erin Shangi
Parasites And Sexual Selection In A Sexually Dichromatic Toad, Nicole Erin Shangi
Electronic Theses and Dissertations
Parasitism is among the most common and successful life history strategies on Earth, leading to constant coevolution between parasites and hosts. Parasites continuously pressure hosts to evolve more effective parasite resistance, fueling interest in the relationships between expression of sexually selected host ornamentation and parasite resistance. By studying parasite-mediated sexual selection we gain unique insights into the evolution of animal traits. In this thesis, I attempt to further our understanding of a sexually dichromatic neotropical anuran by studying its parasites in the context of sexual selection. Firstly, in the General Introduction (Chapter 1), I reviewed important background information key to …
The Function And Evolution Of Wood-Warbler Flight Calls (Parulidae), Zach G. Gayk
The Function And Evolution Of Wood-Warbler Flight Calls (Parulidae), Zach G. Gayk
Electronic Theses and Dissertations
Animals produce vocalizations to communicate with territorial rivals, to communicate with potential mates, to alert others of predators, or to stay in contact with other animals. To date, little research has focused on the vocalizations that animals use to communicate during migration. Many birds produce flight calls, which are short calls given by migratory birds on the wing. The function of flight calls is poorly understood but they are thought to help migrants maintain contact with other individuals during movements between breeding grounds and wintering grounds. Across four data chapters in my dissertation, I investigated the function and evolution of …
Physiological State Determinants Of Maternal Cortisol Signaling And Its Impact On Offspring Quality And Fitness, Sydney Currier
Physiological State Determinants Of Maternal Cortisol Signaling And Its Impact On Offspring Quality And Fitness, Sydney Currier
Electronic Theses and Dissertations
Assessing the intergenerational effects of maternal stress is important for predicting how offspring will respond to changing environments. The overall aim of my thesis was to quantify the effects of maternal state on maternally derived egg cortisol and determine whether this variation in egg cortisol impacts Chinook salmon offspring performance and fitness in a sex-specific way. I quantified within-female changes in maternal energetics and reproductive metrics that I linked to egg quality and ultimately embryo survival. I found egg cortisol increases with increasing maternal plasma cortisol, and increases further as plasma cortisol levels rise with each day that eggs are …
Bioacoustic Studies Of Population Size And Microdialects In An Island-Living Savannah Sparrow Population, Abby Lynn Jill Hensel
Bioacoustic Studies Of Population Size And Microdialects In An Island-Living Savannah Sparrow Population, Abby Lynn Jill Hensel
Electronic Theses and Dissertations
Bioacoustic monitoring provides an innovative technique for studying the behaviour and ecology of wild birds. In this thesis I use bioacoustic monitoring as a tool for studying Savannah Sparrows (Passerculus sandwichensis). In my first data chapter, I tested the accuracy of passive acoustic monitoring in estimating population size and annual survival in an island population of Savannah Sparrows. Six years of data reveal that passive acoustic monitoring with autonomous recorders provides accurate underestimates of population size and annual survival. I found that passive acoustic monitoring estimated population size with 74% accuracy, with higher accuracy in low density years. I also …
Examining The Links Between Environmental Variation, Foraging Behaviour And Foraging Success In An Arctic Seabird, Alyssa Eby
Electronic Theses and Dissertations
Arctic regions are experiencing increasing variability in inter-annual sea ice dynamics ultimately impacting marine Arctic ecosystems. Arctic-breeding seabirds, such as thick-billed murres (Uria lomvia) are thus likely to be negatively impacted by fluctuating environmental conditions through its influence on prey availability. Additional extrinsic factors (colony size and chick demand) and intrinsic factors (sex) are also likely to impact foraging behaviour and success of murres in combination with environmental conditions. First, we tested the effect of colony size on colony sensitivity to environmental change at two low Arctic colonies of varying sizes, Coats Island, Nunavut and Digges Island, Nunavut …
Negative Resistance And Resilience: Biotic Mechanisms Underpin Delayed Biological Recovery In Stream Restoration, Isabelle C. Barrett, Angus R. Mcintosh, Catherine Febria, Helen J. Warburton
Negative Resistance And Resilience: Biotic Mechanisms Underpin Delayed Biological Recovery In Stream Restoration, Isabelle C. Barrett, Angus R. Mcintosh, Catherine Febria, Helen J. Warburton
Great Lakes Institute for Environmental Research Publications
Traditionally, resistance and resilience are associated with good ecological health, often underpinning restoration goals. However, degraded ecosystems can also be highly resistant and resilient, making restoration difficult: degraded communities often become dominated by hyper-tolerant species, preventing recolonization and resulting in low biodiversity and poor eco-system function. Using streams as a model, we undertook a mesocosm experiment to test if degraded community presence hindered biological recovery. We established 12 mesocosms, simulating physically healthy streams. Degraded invertebrate communities were established in half, mimicking the post-restoration scenario of physical recovery without biological recovery. We then introduced a healthy colonist community to all mesocosms, …