Browsing by Author "Brigham, Mark"

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Open Access
Celebration Of Authorship Program 2019-2020
(University of Regina Library, 2020) Afolabi, Taiwo; Belisle, Donica; Beveridge, Daniel M.; Brigham, Mark; Duggleby, Jim; Fox, Bevann; Grimard, Céleste; Hillabold, Jean R. (pen name: Jean Roberta); Hu, Shuchen; Koops, Sheena; Lewis, Patrick; Lockhart, Daniel; Marsh, Charity; Oehler, Alex; Petry, Yvonne; Powell, Marie; Pridmore, Helen; Reul, Barbara; Robertson, Lloyd Hawkeye; Ruddell, Rick; Schultz, Christie; Stonechild, Blair
While our physical circumstances may have changed this year, the commitment of the Dr. John Archer Library and Archives to celebrate the many and varied accomplishments of University of Regina’s authors has not. While we cannot gather together to celebrate in person, this booklet highlights the impressive and wide-ranging scholarship of our faculty, staff, alumni, and students. One of the things that we have learned in this unprecedented time is that even when we are apart, the written word creates community. I want to recognize and congratulate all of our 2020 authors, and thank them for their contributions to building our local, provincial, national, and international communities.
Open Access
Celebration Of Authorship Program 2020-2021
(University of Regina Library, 2021) Afolabi, Taiwo; Bates-Hardy, Courtney; Battis, Jes; Bradley, Crista; Brigham, Mark; Carter, Claire; Clausson, Nils; Cote, Lynn; Cote, Margaret R.; Coupal, Chelsea; French, Lindsey; Gachek, James; Hanson, Cindy; Hu, Shuchen; Juschka, Darlene; Khan, Tanisha; Macdonald, Iain; Marsh, Charity; Melançon, Jérôme; Morgan, R. Grace; Okimasis, Jean L.; Piercey, Robert; Plummer, David William; Powell, Mary; Purdham, Medrie; Ratt, Solomon; Trussler, Michael; Wolvengrey, Arok
The past year has disrupted many things in both our academic and personal lives, but something that has not changed is the commitment of the University of Regina community to advancing research and sharing knowledge and stories with a world-wide audience. The Dr. John Archer Library and Archives is again proud to unveil our new Celebration of Authorship booklet, highlighting books and other creative works published in-print or electronically over the past year by faculty, staff, students, retirees, and alumni of the University of Regina and its federated colleges.
Open Access
Celebration Of Authorship Program 2021-2022
(University of Regina Library, 2022) Abbott, Sarah; Afolabi, Taiwo; Ashton, Emily; Bliss, Stacey; Bonner, William; Bradley, Crista; Brigham, Mark; Campbell, Ian; Campbell, Lori; Carter, Heather; Chadwick, Sydney; Chiefcalf, April; Clarke, Paul; Cliveti, Monica; Clune, Laurie; Demers, Jason; Donovan, Darcy; Eisler, Dale; Eaton, Emily; Elliott, Patricia W; Enoch, Simon; French, Lindsey; Gachek, James; Gardiner, Christopher Campbell; Berard-Gardiner, Shannon; Gebhard, Amanda; Grahame, Ann; Han, Yu (Jade); Hanson, Cindy; Hart, Mel; Hu, Shuchen; Hurlbert, Margot; Isiaka, Abiodun; Jaffe, JoAnn; King, Alex; Koops, Sheena; Kossick, Don; Long, Timothy; Maeers, Esther; Mair, Leslea; Mathes, Carmen Faye; Munro, Emelia; Naytowhow, Joseph; Phillips, Kaetlyn; Polster, Claire; Quark, Amy; Ramsay, Christine; Ricketts, Kathryn; Rasmussen, Ken; Reul, Barbara; Rennie, Morina; Rolli (Charles Anderson); Ruddy, Evie Johnny; Russell, Gale; Sardarli, Arzu; Saul, Gerald; Doke Sawatsky, Katie; Sellers, Cora; Snider, Amy; Stadnichuk, Cheryl; Stevens, Andrew; Stratton, Florence; Swan, Ida; Tomesh, Trevor; Trussler, Michael; Vélez, Maria; Wilson, Ken
For the first time in three years, we are thrilled to be again gathering in person to celebrate the published scholarly and creative work of our University of Regina community. Archer Library is proud to unveil the 2021-22 University of Regina Celebration of Authorship Program booklet. This downloadable publication highlights University of Regina authors/creators of books, edited proceedings, sound recordings, musical scores and film or video recordings published over the last year in any format (print or electronic). We encourage you to take a moment to view the program booklet and extend your congratulations to all of the University of Regina students, faculty, staff, and alumni who are being celebrated this year.
Open Access
Comparative Ecology of Three Sympatric Snake Species in Southwestern Saskatchewan
(Faculty of Graduate Studies and Research, University of Regina, 2012-07) Gardiner, Laura Elaine; Somers, Christopher; Poulin, Ray; Brigham, Mark; Pruss, Shelley D.
My research focused on the comparative ecology of three sympatric snake species which are of conservation concern in southwestern Saskatchewan: eastern yellow-bellied racers (Coluber constrictor flaviventris), a Threatened species in Canada; bullsnakes (Pituophis catenifer sayi), Data Deficient, and; prairie rattlesnakes (Crotalus viridis), yet to be assessed, but considered a high priority candidate. Few studies on snake ecology have collected data for multiple species at the same site, a factor potentially important for understanding resource partitioning and competition between sympatric species. Furthermore, identifying which resources elicit competition may be critical for the conservation and management of endangered species. I used radio-telemetry, GIS, and multivariate modeling to identify and compare habitat use by racers (n = 33), bullsnakes (n = 16), and rattlesnakes (n = 23) in and around Grasslands National Park, Saskatchewan, Canada. Used and available macrohabitat sites were compared to quantify habitat use by these species. I found that although all species hibernate in communal den sites, during the active season they disperse into different macrohabitats across the landscape. As a result, home ranges were dumbbell-shaped with activity centers near hibernacula and in well-defined areas used in summer, and these centers of activity were connected by narrow corridors. Bullsnakes had the smallest home range (4.6 ± 0.7 ha), while racers (14.2 ± 0.9 ha) and rattlesnakes (13.9 ± 1.5 ha) were similar. Racers strongly selected for riparian areas, bullsnakes tended to inhabit valley grassland habitats, and rattlesnakes tended to be associated with prairie dog colonies. Some rattlesnakes travelled great distances (over 11 km) from the dens compared to the other species (bullsnake maximum = 4 km; racer maximum = 5 km), which may be a result of the macrohabitat selected being more patchily distributed in the landscape. In addition, I identified microhabitat selection by rattlesnakes which selected for sites with cover (e.g. shrubs and burrows) along the edges of prairie dog colonies. The habitat use by the three species I studied is consistent with habitat partitioning during the active season, though overlap does occur at the overwintering sites and in movement between selected macrohabitats. In addition to the general ecological value of my findings, the results of this study will be useful in aiding designation of critical habitat for the eastern yellow-bellied racer and contribute to assessment of bullsnakes and prairie rattlesnakes in Canada.
Open Access
Dietary Niche and Foraging Ecology of a Generalist Predator, Double-Crested Cormorant (Phalacrocorax Auritus): Insight Using Stable Isotopes
(Faculty of Graduate Studies and Research, University of Regina, 2012-04) Doucette, Jennifer Lee; Somers, Christopher; Brigham, Mark; Wissel, Bjoern; Fallat, Shaun; Hobson, Keith
The ability of predator populations to expand their ranges and adapt to new environments is often attributed to having a generalist dietary strategy, which is thought to be represented both at the population and individual level. Cormorants (Phalacrocorax spp.) are considered to be opportunistic generalists capable of using a wide variety of aquatic prey. This reputation is partially responsible for the global conflict between piscivorous cormorants and fish harvesters, which is one of the most widespread wildlife management issues in history. Despite the persistent belief that cormorants adversely affect economically important fish populations, relatively little is known about their trophic ecology and habitat use. Stable nitrogen and carbon isotopes are popular tools for studying food webs, and offer a comprehensive assessment of diet, trophic position, and ecological niche when combined with traditional diet analyses. However, the interpretation of isotope data may be confounded by variation in the lipid content of sample tissues. No validated lipid-normalization procedures are currently available for any cormorant species, or any fish-eating birds. As such, I first determined the effect of lipids on the stable carbon and nitrogen isotopes (δ13C and δ15N) values in cormorant tissues, and tested three published lipid-normalization models on stable isotope signatures in double-crested cormorant (P. auritus) muscle and liver tissues. The presence of lipids in cormorant muscle and liver altered the stable isotopes values, indicating corrections were required. However, the effects of lipids in cormorants were unpredictable and thus violated a major assumption of published lipid-normalization models. As a result, lipids must be chemically removed from cormorant muscle and liver tissue. I then examined the diet and trophic position of breeding populations of double-crested cormorants from three different lakes. The results revealed that cormorants generally occupied top-predator positions and relied heavily on pelagic prey in all food webs examined. The isotopic values of cormorants and pelagic predatory fish were sometimes similar, suggesting that dietary overlap is possible. To determine whether cormorants are true dietary generalists I studied double-crested cormorants from breeding colonies spanning three major ecoregions. Analyses of stomach contents revealed that at the population level cormorant diet varied widely by location, likely reflecting local food-web structure. However, within populations individuals were much more specialized than expected. Temporal shifts in δ13C and δ15N values in cormorant tissues with different turnover rates (muscle vs. liver) indicated that foraging varied among populations. The dietary niche occupied by cormorants will affect their interactions with fish, highlighting the importance of understanding their impacts to fish populations both at the population and individual level. Ultimately, my research has shown that cormorants do not consume prey indiscriminately, and instead may have more specific and uniform dietary niche requirements than previously considered. From a management perspective, cormorants should not be assumed to have negative effects on fish in all situations; however, further attention is required to determine the impacts of dietary overlap with sport fish. Ecologically, I have shown that generalist species can be much more consistent and specialized than previously considered. Further, individuals within generalist species may be highly specialized, which will change the overall effects of the population on other species in the food web.
Open Access
An exploratory consideration of cognition and physiology in athletes following concussion
(Faculty of Graduate Studies and Research, University of Regina, 2023-03) Lillie, Garrett Richard; Dorsch, Kim; Neary, J. Patrick; Mang, Cameron; Brigham, Mark
A mild traumatic brain injury (mTBI), colloquially known as a concussion, is an injury of the brain that often results in significant functional impairment for days, weeks, or even months. While the most common symptoms of concussion have been well documented and studies frequently note a deficit in either higher-level cognitive functioning and autonomic physiological control, there is a lack of research describing the effect of concussion on executive functioning and heart rate variability (HRV). The aim of this study was to address gaps in literature by describing changes in an individual’s executive functioning and physiology simultaneously following a concussion using two investigative approaches, using the theory of neurovisceral integration as a guiding framework. Secondary data from University of Regina athletes was used to examine baseline executive functioning (measured by Neurotracker®) and athlete HRV transformed from ECG. These results were subsequently compared to the same measures postinjury. Prior to review of data from the 2019-2020 academic year, there was an expectation that occurrence of a concussion would be associated with a decrease in Neurotracker® performance, Mean R-R intervals (Mean R-R), and Root-Mean-Square-Difference of successive R-R intervals (RMSSD) while also being associated with increases in Low-Frequency/High-Frequency (LF/HF) ratio and Standard Deviation 2/Standard Deviation 1 (SD2/SD1) ratios. Across a sample of eight participants, only one participant experienced the expected change in variable while the two participants that experienced symptoms the longest, featured smaller deviations from their baselines. My study was exploratory in nature and suggests directions for future research.
Open Access
Furry and Feathered Bats: Myths, Mysteries, and Mushrooms
(University of Regina Library, 2012-10-31) Brigham, Mark
When: Wednesday, October 31 1:00pm – 2:00pm Where: University of Regina Main Campus Classroom Building Lecture Theatre 128 (CL 128)
Open Access
The heat shock response in embryonic and young of the year juvenile round whitefish (prosopium cylindraceum)
(Faculty of Graduate Studies and Research, University of Regina, 2017-03) Murillo, Andrea Michelle; Manzon, Richard; Brigham, Mark; Somers, Christopher
I investigated the effects of acute, increased temperatures on round whitefish embryos at the protruding mouth stage and young-of-the-year (YOY) juveniles at 3.5 months post hatch by characterizing the kinetics of the heat shock response (HSR). The HSR provides protection from a variety of stressors (i.e., thermal stress) at the cellular level and is characterized by the upregulation of a suite of proteins called heat shock proteins (Hsps). Round whitefish embryos were exposed to two heat shock (HS) temperatures (6 or 9 °C above control temperature) for 4 different lengths of time (1, 2, 3, or 4 h) followed by a 2 h recovery period at the control temperature of 4 °C, a typical incubation temperature for round whitefish embryos. Post-HS recovery was also examined by exposing embryos to a 2 h HS at 9 °C above control temperature followed by a recovery period of 0, 2, 4, 12, 24, or 48 h at the control temperature of 4 °C. YOY juveniles acclimated to an ecologically relevant 10 °C were exposed to three different HS temperatures (6, 9, or 12 °C above control temperature) for 4 different lengths of time (1, 2, 3, or 4 h) and not given a recovery period. Post HS recovery was examined by exposing YOY juveniles to a 2 h HS at 6, 9, or 12 °C above control temperature followed by a 0, 1, 4, or 8 h recovery period at the control temperature of 10 °C prior to sampling. In embryos, hsp70 mRNA levels were the only consistently upregulated heat shock protein (Hsp), whereas in YOY juveniles hsp70 and hsp47 mRNA levels were consistently upregulated. Furthermore, in comparison to juveniles, embryos took a longer time to initiate a HSR but once upregulated the HSR was long lasting in both life history stages. These data indicate that embryos and juveniles are able to trigger a protective HSR which presumably aids them in surviving a 3 h HS of +9 °C and a 4 h of HS +12 °C, respectively. This suggests HSR is one of the mechanisms available to round whitefish when experiencing thermal stress in fluctuating environments.
Open Access
The influence of embryo incubation temperature on later life aerobic performance of Lake Whitefish (Coregonus clupeaformis) and Yellow Perch (Perca flavescens)
(Faculty of Graduate Studies and Research, University of Regina, 2023-03) Dorsey, Spencer William; Manzon, Richard; Brigham, Mark; Somers, Christopher; Tierney, Keith
Temperature represents one of the most influential abiotic factors affecting all living organisms. Ectotherms, including fish, can be affected by temperature at the cellular, individual, population, and community levels. In modern times, climate change and thermal pollution pose major threats as they threaten to elevate water temperatures, therefore limiting optimal thermal habitats and exposing species to suboptimal environmental conditions. While adult fish of many species have the capacity to avoid these thermally impacted areas, early life stages (i.e., embryonic, larval, and juvenile) are typically limited in mobility and lack the ability to avoid these areas. These early life stages are especially vulnerable, as this is a time of rapid growth and development. While numerous studies have evaluated the effects of temperature during development on hatching success, developmental rates, and phenotypic plasticity, few have assessed its effects on later life whole-animal performance. I used intermittent swim respirometry to evaluate the effects of embryo incubation temperature on two measurements of whole-animal aerobic performance: aerobic scope and critical swimming speed. I chose to use two species of fish that use distinct reproductive characteristics, the fall spawning Lake Whitefish and the spring spawning Yellow Perch. I hypothesized that whole-animal aerobic performance of both species would be reduced when embryos were incubated at temperatures 3 °C above optimal. I also hypothesized that Lake Whitefish would be impacted more drastically than Yellow Perch due to their narrower thermal tolerance. Finally, I predicted that whole-animal aerobic performance would be maximized at temperatures near the thermal preference of the species, respectively. To test my hypotheses, I first incubated Lake Whitefish and Yellow Perch embryos at 2 and 5 °C, and 15 and 18 °C, respectively. I then reared Lake Whitefish at common-garden temperatures of 12 °C for 14 to 16 months and Yellow Perch at 18 °C for and 9 to 12 months. Following the rearing periods, Lake Whitefish and Yellow Perch were split into experimental temperature groups and acclimated to 15 and 19 °C, and 20, 24, and 28 °C respectively, for 2-4 weeks before swim respirometry trials began. I found that embryo incubation temperature influences the whole-animal aerobic performance of Lake Whitefish but does not affect Yellow Perch. Lake Whitefish incubated as embryos at 5 °C demonstrated a reduction in critical swimming when acclimated to 15 °C as juveniles. An interaction between the embryo incubation temperature and the response to juvenile acclimation temperature was also detected in Lake Whitefish, where the routine metabolic rate of fish incubated as embryos at 5 °C did not increase when acclimated as juveniles to 19 °C compared to 15 °C. No influence of embryo incubation temperature was observed in the whole-animal aerobic performance of Yellow Perch. My results imply that Lake Whitefish and potentially other species that demonstrate similar developmental characteristics are likely to be impacted by increases in global water temperatures. Decreases in whole-animal aerobic performance could have negative impacts on survival and recruitment. Yellow Perch and other species that share developmental characteristics will be impacted to a lesser extent. Although the mechanisms responsible for the effects of embryo incubation temperature on later life whole-animal aerobic performance are not well understood, this study gives a baseline for further research to build upon. By understanding the potential for embryo incubation temperature to influence later life whole-animal aerobic performance, future studies can be conducted to isolate the mechanisms associated.
Open Access
The Influence of Weather, Time of Season, and Time of Day on Bullsnake (Pituophis atenifer sayi) Thermoregulation and Habitat Selection
(Faculty of Graduate Studies and Research, University of Regina, 2021-04) Johnson, Noah Brian; Somers, Christopher; Poulin, Ray; Brigham, Mark; McAlpine, Donald
The grasslands of Western Canada are exposed to one of the most variable terrestrial climates on Earth. Ectothermic reptiles such as the bullsnake (Pituophis catenifer sayi) must respond to this variation by altering their behaviour over daily and seasonal scales. In Chapter 2, I addressed questions regarding the extent to which bullsnakes thermoregulate. I examined how body temperatures (Tb) varied with available operative temperatures (Te) over an active season at a site in southwestern Saskatchewan, Canada. Bare ground Te was variable (x̄ min = 9.3, x̄ max = 31.4°C) and was outside voluntary limits (15 – 35°C) 45 % of the time. However, burrows created by mammals provided stable thermal conditions that remained within voluntary ranges for 93 % of the active season. Bullsnakes should not need to move far to thermoregulate because of thermal gradients (up to 27.2°C in less than 1 m) formed between burrows and patches of sun-exposed bare ground. Time of day, day of year, and bare ground Te (R2 = 0.578) were useful predictors of Tb (x̄ min = 20.1, x̄ max = 29.1°C). Bullsnakes thermoregulated by conforming to Te near their preferred range (21 to 27°C), selecting locations that enabled heating up below this range, and avoiding warmth above this range. My results support the hypothesis that predicts reptiles will thermoregulate more when environmental temperatures deviate from preferred ranges, and when energetic costs of movement are lower due to high thermal heterogeneity. Despite the extreme surface temperatures of high-latitude grasslands, thermoregulation may be easier for snakes than in high-latitude forests due to the thermal gradients available because of burrows in areas exposed to sun. In Chapter 3, I examined the influence of time (time of day, day of year) and weather (temperature, humidity, and precipitation) on a suite of behaviours in 4 bullsnake populations in Saskatchewan. I studied variation in 4th order use and selection for burrows, concealment probability, relocation probability, and movement distances. Bullsnakes altered behaviours in response to time and weather. The greatest variation was explained for concealment (R2 = 0.244) and 4th order habitat selection (R2 = 0.144 – 0.169). However, 4th order habitat use (R2 = 0.0366), relocation (R2 = 0.0419), and movements (R2 = 0.025 – 0.071) were relatively unpredictable based on time and weather variables. Movement distances were particularly variable among individuals. Overall bullsnake activity was highest in spring and during afternoons. Poor weather and unfavourable temperatures were avoided. Humidity was more important than expected. Humidity (or precipitation) was negatively associated with activity in spring or at cool temperatures, but positively associated with activity in summer or at hot temperatures. I suggest that current management recommendations for bullsnakes are valid. However, sample biases could create the false appearance of different habitat requirements among populations if weather conditions, time of day, or season were to differ among studies. Time and weather were useful for predicting the probability of finding bullsnakes on the surface (AUC = 0.8015) and should be used to forecast optimal conditions for surveys. Snake behaviour is often considered to be unpredictable, but the results of Chapter 2 and 3 suggest that weather variables and time are important for predicting bullsnake behaviour, and particularly general surface activity. Behaviours varied widely over the active season, and the effects of time and weather variables were context dependent. My thesis highlights the importance of long study periods under a wide range of conditions to understand the ecology of reptiles in highly seasonal environments.
Open Access
Measures of Cardioautonomic Dysfunction as Markers of Sport Related Concussion
(Faculty of Graduate Studies and Research, University of Regina, 2020-12) Teckchandani, Taylor A.; Neary, J. Patrick; Candow, Darren; Mang, Cameron; Brigham, Mark
The field of concussion research is vast but lacking in uniformity when implementing or recommending evaluative protocols. Of the pathological characteristics associated with concussion, autonomic dysfunction includes but is not limited to a dysregulation of autonomic afferent and efferent pathways in both cortical and medullary regions, resulting in impaired intrinsic autoregulatory function influencing inotropic and chronotropic aspects of myocardial contractility, as well as vascular smooth muscle regulation (1,2). Popular methods of assessing autonomic function in the wake of a concussion include heart rate variability (HRV) analysis, blood pressure variability analysis (BPV), and spontaneous baroreceptor sensitivity (SBRS). This project aims to examine the impact of concussive trauma on cardioautonomic functioning and multilevel cardioautonomic integration across two studies in 65 otherwise healthy college-aged athletes, with a focus on heart rate variability, blood pressure variability, and the multilevel autonomic integration required for cardiac baroreflex functioning across six time epochs (baseline, days 1-3, days 4-7, days 8-11, days 12-15, and days 16+) using rest and rhythmic breathing portions (0.1 Hz) of the Neary Protocol. Two within-subject repeated-measures multilevel modelling approaches were used for statistical analysis to address non-equidistant sampling intervals present in the data set, with a Sidak post-hoc test for pairwise comparisons with alpha set at p<0.05. I conclude that rhythmic breathing is the preferred methodology to assess cardioautonomic dysfunction in the wake of a concussion, integrate heart rate variability and baroreceptor sensitivity values, and speculate about a potential mechanism responsible for patterns of cardioautonomic dysfunction to paint a picture of the multilevel autonomic integration that can be readily evaluated to diagnose concussion.
Open Access
Potential Impacts of Zebra Mussel Invasion on Gamefish Health and Prey Availability in Prairie Lakes
(Faculty of Graduate Studies and Research, University of Regina, 2022-03-30) Ofosu, Caroline Barbara; Wissel, Bjoern; Somers, Christopher; Brigham, Mark; Hansen, Gretchen
Invasive species are a threat to global aquatic ecosystems. Nonetheless, their impacts can be heterogeneous across systems. Recent reports suggest Saskatchewan (SK) prairie lakes are highly prone to zebra and quagga mussels (ZQM) given their proximity to invasive corridors of Manitoba and three US states (Montana, North Dakota, and Minnesota) where they have been reported. As the effect of ZQM on native species is variable and context-dependent across locations and time, an understanding of prevailing biological, physical and chemical conditions supporting various cohorts of fish communities is necessary for prioritizing mitigation efforts to address the potential effects of these dreissenids in uninvaded systems. To gain these important insights, I investigated diet composition and body conditions of three ecologically and recreationally important gamefishes; walleye (Sander vitreus), northern pike (Esox lucius), and yellow perch (Perca flavescens) sampled from 18 SK prairie lakes. In addition, I assessed the impact of fish size and environmental variables on gamefish body conditions. Twenty-three prey taxa were found in the diets of these fishes. While both invertebrates (amphipods) and fish formed significant constituents of walleye diets, pike concentrated more on fish prey, whereas perch relied more on invertebrates (chironomids and amphipods). Zooplankton was only a minor contributor to the diets of all three gamefish species. Body conditions of walleye and pike decreased with size, but yellow perch populations were in consistently good condition across all size groups. These results suggest preferred fish prey of larger piscivores (i.e., pike and walleye) may be present in insufficient quantity. Lake productivity and alkalinity influenced body conditions of large-sized walleye and yellow perch. The scarcity of pelagic zooplankton prey in the diets of small-sized gamefishes implies these populations may be less threatened by future ZQM invasion than previously assumed. Next, I contrasted stomach content data and Carbon (C), Nitrogen (N), with Sulfur (S) stable isotope analyses to better quantify the relative importance of various foraging habitats to the three gamefish species. Bayesian Mixing models predicted that in about 70% of our study lakes > 55% of gamefish diets were sourced from the littoral region, whereas in ~30% of surveyed lakes, > 55% of gamefishes diets was sourced from the pelagic habitat. General evidence of similar reliance on sediment S sources in lakes where two species co-occurred (walleye and pike or walleye and perch) was observed. Overall, the three predominant gamefishes exhibited comparable dependence on the three feeding habitats (littoral, pelagic, sediment) across SK prairie lakes. Findings of stomach content analysis (SCA) and stable isotope analysis (SIA) were assessed to determine how the two techniques corroborate, contradict or complement each other. Results indicated a lack of correspondence between the two methods utilized in examining walleye diets, suggesting the need to use both techniques as complements for more robust results. Finally, because future invasion by ZQM is expected to significantly impact energy sources of gamefishes, I examined the current environmental controls of reliance on pelagic, littoral, and sediment-based diets. Walleye reliance on pelagic energy sources increased with the maximum depth of lakes and decreased with total dissolved solids (TDS) concentrations, implying the contribution of pelagic diets increase for fish populations in deeper and less saline lakes. However, sediment-based diets were not influenced by any of the selected environmental parameters. Integrating SCA and SIA overall helped to advance our understanding of feeding habits of gamefish populations in SK prairie lakes and demonstrates the value of combining these analyses for a comprehensive understanding of feeding interactions within aquatic ecosystems.
Open Access
The response of the avian community to 40 years of land cover change within the Aspen Parkland and Moist-mixed Grassland ecoregions of the Canadian prairies
(Faculty of Graduate Studies and Research, University of Regina, 2015-03) Kovatch, Leah Catherine; Somers, Christopher; Davis, Stephen; Brigham, Mark; Piwowar, Joseph; Morrissey, Christy
Since European settlement, over 80% of grassland habitat has been lost in the Canadian prairies, primarily in the Moist-mixed Grassland and Aspen Parkland ecoregions. Native grassland continues to be lost and degraded. Reduction of fire and overgrazing by livestock has allowed woody vegetation to encroach on grasslands. Grassland bird populations in the northern extent of their range have undergone steep declines whereas woodland bird populations have increased. It is unknown whether population fluctuations over the past 40 years are a result of land cover changes during this period. The goal of my research was to address this knowledge gap with the use of long-term datasets from the Breeding Bird Survey (BBS) and remote sensing. My objectives were to: (1) assess changes in bird population trends over the past 40 years along a sub-set of representative BBS routes; (2) determine land cover change along these BBS routes from 1970 to 2012; and (3) determine if there is a relationship between land cover change and bird population trends over the past 40 years. I classified 1970 and 2012 land cover (cultivated, native grassland, and woodland) within an 800 m radius of point-count locations along nine BBS routes located in the Moist-mixed Grassland and Aspen Parkland ecoregions of Saskatchewan and Manitoba. Bird population trend estimates from 1970 to 2011 were compiled for each BBS route and I grouped species based on breeding habitat guild (grassland, scrubland, and woodland). On average, grassland and scrubland bird populations decreased by 1.5 %/yr and 0.7 %/yr, respectively, and woodland birds increased by 1.4 %/yr along routes. The amount of land cover change from 1970 to 2012 was small along routes, indicating the majority of landscape change occurred prior to 1970. Cultivated land and woodland increased on average by 2.2% and 0.1% respectively, and native grassland decreased by 2.1%. Although absolute native grassland loss was small overall, proportion of loss relative to what was present in 1970 was large. The relatively small change in woodland cover was likely a result of land being cleared for cultivation but at the same time encroaching on native grassland. Overall, I found no statistically significant relationship between land cover change and bird trend estimates. Possible explanations for a lack of a relationship include: (1) land cover change was too small to affect bird populations; (2) common and generalist species included in community analyses are less affected by the documented habitat changes; (3) factors other than recent land cover change are affecting bird populations (i.e., fragmentation, patch size, local vegetation); and (4) habitat loss is occurring on migration and winter areas. Additional research is needed to address shrub encroachment rates in my study area, as well as to investigate the effects of habitat changes on grassland specialists.
Open Access
Reviewing and Reshaping My Teaching Towards a More Socially-Just Practice: A Self-Study
(Faculty of Graduate Studies and Research, University of Regina, 2017-12) Kelsey, Rosalyn Denise; Nolan, Kathleen; Tupper, Jennifer; Schick, Carol; Brigham, Mark; Lund, Darren
This research text is a self-study into my development as a critical pedagogue. In it, I seek to investigate two research questions: (1) how do tensions in my teaching illustrate the systemic challenges of race and gender, which I face on a day-to-day basis, as I work towards a more socially-just teaching practice; and (2) how does the analysis of racial and gender-based teaching tensions help guide my growth toward a more socially-just professional practice? My evolving understanding of my social position in relation to systems of oppression and its effect on my teaching are central to this study. Through this self-study, I have come to discover that when considering power, responsibilities, space, and lived-experiences, the point is to not only acknowledge oppressive systems and one’s place in supporting those, but to go beyond one’s current positioning. Change must be created first (and extensively) within one’s self (as was demonstrated in this self-study), and only then within society. If action does not flow from ongoing, critically enlightened acknowledgement of power symmetries, then the impact of any actions will uphold and preserve systems of injustice. As stated in my data, “I think that’s the whole point about social justice is you never—you never really get there”; it’s a constant process of discovering and learning about one’s own positioning and sitting in that discomfort.
Open Access
Rodent Responses to Land Modification for Agriculture: Implications for Trophic Dynamics In the Northern Great Plains
(Faculty of Graduate Studies and Research, University of Regina, 2019-03) Heisler, Leanne Michelle; Hall, Britt; Simpson, Gavin; Vanderwel, Mark; Brigham, Mark; Hart, Melanie; Piwowar, Joseph; Brook, Ryan
My thesis examines rodent species responses to agricultural land modification and their implications for trophic dynamics on the northern Great Plains. I first validated owl pellet analysis as a landscape-level sampling method for small mammal studies by comparing mammal diversity and composition between owl pellets and trapping from 27 studies of 15 owl species. Then using a dataset of >10,000 owl pellet samples collected from landscapes varying in agricultural intensity, I estimated rodent species responses to habitat loss and fragmentation, predicting species would respond relative to their affinity for unmodified grassland habitat. I found species responded irrespective of grassland specialization, indicating habitat specialization is not a universal proxy for sensitivity to land modification. I investigated the implications of these responses to sympatric great horned owl and burrowing owl diets, predicting great horned owls may competitively exclude endangered burrowing owls when diet composition was similar between the two species. I found both owl diets were dominated by small mammal prey in similar species composition, suggesting competitive exclusion of burrowing owls where their home ranges overlap with great horned owls. I also investigated whether woody encroachment facilitated increased great horned owl densities in mixed-grass prairie. Using 51 building surveys, I estimated the effect of forest cover on the presence of great horned owls in buildings. My results were inconclusive; I observed a potentially biologically relevant but statistically insignificant decline in building use with increasing percent forest cover, indicating my study lacked statistical power or influential conditions (e.g., internal conditions, forest edge, prey availability near buildings) responsible for owls roosting in buildings. This is the first landscape-level perspective of rodent responses to land modification and their implications for two sympatric raptor species. On the northern Great Plains, rodent population responses to land modification may change the spatial composition of rodent communities, facilitating interactions between great horned owls and burrowing owls that may further limit burrowing owl population persistence on the northern Great Plains. Globally, these results inform a broader debate regarding which conservation strategy, land sparing or land sharing, will be most effective at meeting global biodiversity targets while increasing food production to feed a growing human population.
Open Access
Sharp-Tailed Grouse (Tympanuchus phasianellus) Habitat Selection and Population Trends in Saskatchewan
(Faculty of Graduate Studies and Research, University of Regina, 2020-12) Burda, Brandon David; Somers, Christopher; Fisher, Ryan; Brigham, Mark; Brook, Ryan
The sharp-tailed grouse (Tympanuchus phasianellus) is a symbol of Saskatchewan and has important cultural and economic status in the province. Over the last few decades this species has been declining in Saskatchewan, especially in southern grassland regions. While the decline in sharp-tailed grouse populations has been variously attributed to habitat loss, degradation, and fragmentation, the major factors affecting population trends remain to be definitively identified. Two areas of importance for research were highlighted by provincial government scientists to inform long-term management and conservation of sharp-tailed grouse in Saskatchewan: (1) identify sharp-tailed grouse habitat and its distribution in the province; and (2) understand population changes in relation to weather conditions. My research was undertaken to address these knowledge gaps for the plains subspecies of the sharp-tailed grouse in Saskatchewan. Leks, communal dancing grounds, form the basis for much of the life history knowledge of sharp-tailed grouse and are often used in the management of the species. Correspondingly, the probability of lek occurrence is an excellent indicator of habitat quality. However, the specific characteristics of the landscape around leks that draws sharp-tailed grouse to an area are still relatively unknown. To study the habitat distribution of plains sharp-tailed grouse in Saskatchewan, I identified lek locations using both contemporary field surveys and historical data collected by the Saskatchewan Ministry of Environment (MOE). I generated a habitat suitability index (HSI) model, which provides a probability of lek occurrence using the known locations compared to various landcover types. I included two variations of each landcover type variable in the HSI: one at a 1x1 km scale and another at a 5x5 km scale. The most important predictors for lek occurrence from the model were the proportion of grasslands at 5x5 km, followed by the amount of grassland within 1x1 km. After the proportion of grasslands, the next most important predictors was the roughness of the landscape (number of topographic changes, with flatter areas being preferred), and the proportion of wetlands, both at the 5x5 km scale. These results together highlight the importance of managing large, heterogenous grassland areas for the occurrence of sharp-tailed grouse leks. Annual changes in weather can have a variety of influences on avian population sizes, either directly or indirectly. I focused solely on the factors which are likely to have direct effects on sharp-tailed grouse. Lek counts are often used as an index of local population sizes due to their centrality to the life history of sharp-tailed grouse, the high site fidelity that male grouse show to leks, and the ability to easily count birds on leks. I tested the effects of the average winter temperature, total summer precipitation, and the average spring temperature on annual lek counts from 1970 to 2004, all of which have been shown to affect sharp-tailed grouse in previous research. Colder winters led to lower average lek counts; whereby average winter temperatures of -25oC resulted in leks losing on average one male compared to the average lek count. In contrast, lek counts had a quadratic relationship with summer precipitation with lek counts reaching a peak at moderate precipitation levels and declining at both low and high levels. The largest declines in lek size were associated with precipitation levels around 30 cm, resulting in the loss of an average of 3-4 males per lek. By better understanding how these annual weather conditions can affect the populations of sharp-tailed grouse, managers can make more informed decisions earlier to better set bag limits.
Open Access
Space Use by Piscivorous Birds, Fish, and Humans on a Multi-Use Lake in Southern Saskatchewan
(Faculty of Graduate Studies and Research, University of Regina, 2021-10) Chupik, Michelle Ann; Somers, Christopher; Brigham, Mark; Finlay, Kerri; Fraser, Gail
On the Great Plains of North America, freshwater lakes are a critical resource in a dry landscape. Recreational development and use of lakes, as well as industrial and agricultural uses, may alter habitat and water quality. Consequently, it is important to understand how economically important fish species (walleye Sander vitreus; northern pike Esox Lucius; and burbot Lota lota) use lakes and identify key areas for protection and management efforts. Conflicts between humans and fish-eating birds over fisheries resources have also emerged and may be exacerbated by the limited availability of freshwater. In this context, the double-crested cormorant (Phalacrocorax auritus) and American white pelican (Pelecanus erythrorhynchos) have been targeted by anglers based on their diet, which is almost exclusively made up of fish. In contrast, the western grebe (Aechmophorus occidentalis) is a fish-eating bird of conservation concern and may be declining primarily due to human development of near-shore habitat. My research examined space use by three different user groups on Buffalo Pound Lake, in southern Saskatchewan, Canada: (1) sport fish; (2) fish-eating birds; and (3) humans (boats). Acoustic telemetry based on 30 fixed receivers showed that individuals of all 3 fish species (burbot, northern pike, walleye) were located in almost all portions of the lake at some point in time. In particular, northern pike occupied nearly the entire lake and also made long-distance movements throughout the study period. However, kernel density analysis identified the northwestern portion of the lake as a “hotspot” for all 3 fish species, with the majority of detections in undeveloped portions of the lake that were seldom used for recreation. These results need to be interpreted with caution, given the poor detection of fish on acoustic receivers for most of the study period. Point counts revealed that double-crested cormorants and American white pelicans had the highest relative densities in areas of Buffalo Pound Lake with undeveloped shorelines. Both of these bird species were often most abundant in the same northwestern portion of the lake used by sport fish, further highlighting this area as a “hotspot” for piscivorous species. In contrast, western grebe relative density was much more evenly spread across the entire lake, including areas with high levels of shoreline development and boating disturbance. The relative density of boats was highest in areas with developed shorelines, and few boats were ever detected in the “hotspot” area for fish and birds described above. My results suggest that the northwest portion of Buffalo Pound Lake needs to be a focal area for long-term habitat protection; more research is needed to determine how western grebes are interacting with humans.
Open Access
Story of a Lost Saskatchewan Premier
(University of Regina Library, 2013-01-30) Brigham, Mark
When: Wednesday, January 30 2:00pm - 3:00pm Where: University of Regina Library Archives & Special Collections Reading Room (LY 107.4)
Open Access
The Use of Object-Based Classification of High Resolution Panchromatic Satellite Imagery for the Inventory of Shelterbelts in the Province of Saskatchewan
(Faculty of Graduate Studies and Research, University of Regina, 2013-03) Pankiw, Joey Ryan; Piwowar, Joseph; Brigham, Mark; Sauchyn, David; Guo, Xulin
The Prairie Shelterbelt Program of Agriculture and Agri-Food Canada, has produced many benefits for farmers and the prairie landscape: reducing soil erosion, protecting crops, controlling snow drifting over highways/roads and providing wildlife habitat. Due to growing concerns about rising levels of carbon dioxide in the atmosphere, the ability of shelterbelts to sequester carbon dioxide may also be of importance. Although the Prairie Shelterbelt Program has been distributing tree and shrub seedlings for more than 100 years, and records of the numbers of trees shipped have been kept, an inventory of the number of trees that have been successfully planted and their locations on the landscape does not exist. When observed on Spot- 2.5 m. panchromatic satellite imagery, shelterbelts have distinct shapes, textures, and spatial relationships with other objects within the landscape. Object-based image classification methods are well suited to segmenting remotely sensed imagery based on these characteristics and have the potential to be used for delineating shelterbelts. In this thesis, Definiens object-based image classification software is shown to be an effective way to create a provincial-scale shelterbelt inventory. The primary objective of this research was to develop a process by which the spatial coverage of shelterbelts in the Province of Saskatchewan could be determined to facilitate the estimation of the amount of carbon being sequestered. The results show that due to the large diversity of agro-environmental conditions across the province, and seasonal and contrast inconsistencies of the panchromatic satellite data used, this was not possible. Nonetheless, the results show that object-oriented classification methods have the potential to detect the location of shelterbelts with an accuracy of over 80%. It is also possible to obtain a reasonable estimate of carbon sequestration. Future shelterbelt inventories should focus on the enhanced data potential found in high-resolution colour-infrared imagery.
Open Access
Variable habitat selection and space use among bullsnake (Pituophis catenifer sayi) populations: distance between seasonal habitats drives space use
(Faculty of Graduate Studies and Research, University of Regina, 2017-04) Edkins, Tera; Somers, Christopher; Poulin, Ray; Brigham, Mark
The distribution of resources determines space use and habitat selection by snakes. Particularly in northern areas, the proximity of overwintering den sites to summering habitat likely influences space use. The resources driving seasonal movements among habitats may vary among populations and thus, space and habitat requirements may also vary. In addition, human modification may affect resource use by altering available habitats and resources. Although previous studies have reported differences in spatial ecology among populations, the driving factors of this variation remain to be addressed for many species. Bullsnakes (Pituophis catenifer sayi) reach their northern range limits in southern Saskatchewan, where they are currently listed as Data Deficient by the Committee on the Status of Endangered Wildlife in Canada. Many studies have focused on core range areas, while northern studies have focused on one population in the Frenchman River Valley, Saskatchewan. The habitat and space requirements identified in these previous studies, however, may not be relevant to all bullsnake populations. I examined bullsnake space and habitat use among independent populations in three river valleys (Frenchman River, South Saskatchewan River, and Big Muddy Valleys) in Saskatchewan, with varying habitat types (natural and anthropogenic) and availability. I tracked bullsnakes using radio-telemetry, estimated home range areas and movement patterns, and measured third and fourth order habitat selection. The objectives of my research were (1) to examine the extent to which habitat selection and space use may vary among populations and (2) to identify important habitat features in common among snakes from different populations. Saskatchewan bullsnakes demonstrated variable space use and movement patterns among populations, exceeding space use requirements previously observed in southern areas. One population (Big Muddy Valley), on average, used 2.7 to 3 times less space, travelled 2.3 to 2.7 times shorter distances from overwintering sites, and had greater home range overlap than snakes from the other populations (Frenchman and South Saskatchewan River Valleys). This suggests that bullsnakes in the Big Muddy Valley had a closer spatial association between seasonal habitats. Bullsnakes appear to be flexible in terms of their third order habitat selection. Native habitats were used as expected across all valleys, but human-modified habitats were used at different frequencies across populations. These differences in habitat selection among populations are most likely due to differences in habitat availability among landscapes. Fourth habitat selection, however, was similar among populations, with bullsnakes selecting for sites typically within 1 m of a refuge site (including burrows, cement pads, and rock piles). It appears that bullsnakes occupy variable-sized home ranges and move variable distances. Bullsnakes also appear to be flexible in terms of how they meet resource requirements across their geographic range via habitat selection at a broad spatial scale. My study did find, however, that at a fine spatial scale refuge sites are an important habitat feature for bullsnakes. Conservation and management strategies are typically broad and are implemented as if populations of the same species have similar habitat requirements. However, my results indicate that this is not the case. As such, management plans may not be applicable to all populations.