PRISM :: Browsing by Author "Galpern, Paul"

Browsing by Author "Galpern, Paul"

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Open Access
Bumble bee use of heterogeneous mountain habitats: A landscape genomic approach
(2023-05-09) Clake, Danielle Jessica; Galpern, Paul; Rogers, Sean; Cartar, Ralph; Vamosi, Jana
Land use modifications and climate change are two of the major factors behind global biodiversity losses. The specific impacts and long-term implications of these changes have yet to be understood for many species. Bumble bees (Bombus sp.) are an important group of pollinators, especially in temperate and montane regions where they are relatively abundant. They are also facing global declines and range shifts. In this thesis I pose several questions investigating the relationship between bumble bees and mountain landscapes. I first ask whether bumble bee abundance and species richness are positively or negatively associated with measures of landscape fragmentation. I then demonstrate patterns of genetic and phenotypic diversity and differentiation in the high elevation taxa Bombus lapponicus sylvicola and assess hypotheses about mechanisms that could be causing the differentiation I observe. Lastly, I test whether gene flow in four bumble bee taxa has been restricted between habitats of differing elevations. To answer these questions, I sampled 22 species of bumble bees from 69 sites across a 40,000 km2 geographic range, where sites were selected to minimize correlations between variables of interest. I extracted DNA from 745 individuals of four different taxa, and used SNPs derived from ddRAD libraries to measure genetic diversity and gene flow. In this thesis I report higher abundance and species richness of bumble bees in locations where surrounding land cover has higher levels of complementation between nesting and foraging habitats, but that abundance and species richness decrease with other measures of fragmentation. I describe a new cryptic subspecies of B. sylvicola based on genetic and phenotypic diversity, and present evidence that it may have differentiated under conditions of gene flow based on adaptation to cold minimum temperatures. Finally, I present evidence that high elevation taxa appear to be able to exchange genes freely across elevations, while taxa associated with lower elevations display patterns of reduced gene flow across elevations. These findings have important implications for the conservation of montane bumble bee species and provide several avenues for future study and investigation.
Open Access
Consequences of Spatial Exploitation in Complex Adaptive Social-Ecological Systems: Managing for Sustainable Freshwater Fisheries
(2018-01-23) Wilson, Kyle Logan; Post, John R.; Cartar, Ralph Victor; Galpern, Paul; Pope, Kevin L.; McDermid, Gregory J.
Freshwater fisheries are complex adaptive social-ecological systems structured by coupled feedbacks between fish and people (e.g., anglers). For example, fishing quality influences angler site choices, and anglers reciprocally impact fish populations at chosen sites through size-selective harvest, thus demonstrating how feedbacks between fish and anglers permeate through whole ecosystems. Overexploitation increasingly threatens these fisheries challenging management with finding robust solutions to sustain these important resources. Yet, we often lack generalization on the social and ecological processes that limit system resilience. This thesis attempts to gain some of that generalization by exploring how whole-system outcomes emerge from cross-scale interactions between fish and anglers. To do this, I used a combination of theory-driven models and empirical case studies on the rainbow trout Oncorhynchus mykiss and lake trout Salvelinus namaycush fisheries of British Columbia and Yukon to find the landscape, social, and ecological consequences of spatial exploitation on these complex systems. In general, I found that system outcomes, like sustainable or overexploited fisheries, strongly depended on both landscape contexts and the strength of social-ecological feedbacks. In doing so, I was able to generalize the kinds of freshwater landscapes at risk of overexploitation. Next, I found that spatial exploitation patterns had cascading effects across freshwater landscapes by influencing ecological processes like the demographic tradeoff between fish body size and abundance or variation in fish life histories. Additionally, I found that angler site choices were influenced by multiple characteristics, like trip contexts, travel costs and fishing quality, allowing me to better identify potential angler impacts on fish populations. I then integrated these spatial, social, and ecological processes to evaluate the kinds of policies that may improve management of the lake trout fishery and found that conservative regulations better balanced both social and ecological objectives. The results of these studies can help inform management on the feedbacks and processes that drive fishery dynamics, how a landscape of fish populations may respond to spatial exploitation, the kinds of landscapes (and populations within those landscapes) at risk of overexploitation, and the efficacy of regulations that target key spatial, social, and ecological processes to sustain freshwater fisheries.
Open Access
Effects of Landscape Age and Salinity on Plant Community Composition and Productivity in Opportunistic and Constructed Wetlands in the Athabasca Oil Sands Region, Alberta
(2023-08) Mombourquette, Ashlee Dawn; Ciborowski, Jan; Chasmer, Laura; Hornung, Jon; Vamosi, Jana; Galpern, Paul
Wetlands comprise 65% of the Athabasca Oil Sands Region (AOSR) surface mineable area and thus support diverse flora (approximately 400 species in Alberta). Due to increased anthropogenic land disturbance activities such as bitumen extraction, reclamation of surface mineable areas will also increase. The resulting reclaimed areas will tend to be sodium-enriched compared to pre-disturbance landscapes. In this thesis, forty young (<40 years old) stratified-randomly selected wetlands were sampled on reclaimed landscapes at Syncrude’s Mildred Lake lease and from reference wetlands in adjacent areas in the AOSR to determine how salinity and age influence the vegetation community composition, and the biomass of six dominant wetland plant species (Carex aquatilis, Calamagrostis canadensis, Carex atherodes, Carex utriculata, Schoenoplectus tabernaemontani, and Typha latifolia) found on reclaimed and reference landscapes. Wetland vegetation communities on reclaimed landscapes differed from those on reference landscapes; however, landscape type had no impact on the biomass of the dominant plant species. Vegetation communities varied along a salinity gradient; species richness was negatively associated with salinity, and vegetative species abundance (percent cover) was lowest in freshwater wetlands and highest in moderately brackish wetlands. Species richness did not differ among wetland classes. However, vegetative species abundance was significantly different among age classes. The biomass produced by each dominant species did not vary with respect to a gradient of salinity or among wetlands of different age classes. These findings may provide a useful frame of reference against which to compare vegetation communities that may be observed in wetlands forming on reclaimed landscapes.
Open Access
Forest Cover Influences the Predictions Made by Species Distribution Models: A Case Study of American hazelnut (Corylus americana)
(2024-10-11) Cramb, Nicholas; Vamosi, Jana; Dawson, Andria; Galpern, Paul; Yeaman, Samuel
Species distribution models can be used to predict climate impacts on biodiversity and guide conservation efforts. However, they may not fully represent biological reality when they entirely rely on climate variables alone and neglect biological interactions. My research objective is to test if including forest cover as a quantitative proxy for shrub-canopy interactions improves the predictive ability of species distribution models. My work focuses on American hazelnut (Corylus americana) as a case-study to test this framework. American hazelnut is a good candidate species because it is widely distributed throughout the eastern temperate and northern forests of North America and is likely to interact with the full gradient of 0 to 100% forest cover. The species remains understudied regarding the determinants of its distribution, despite an excellent fossil pollen record. This project used the hazelnut fossil pollen record to model the influence of canopy cover on distribution through time and to test whether hazelnut niche has been stable over time. For distribution models of American hazelnut, I found no difference in model performance when land cover variables are included at a continental extent. However, at a regional extent I found significant increases in model performance when forest cover was included. These findings suggest that land cover can more precisely define where species habitat exists at a local level compared to climate variables alone. Distribution models developed using fossil pollen occurrences and climate simulations indicate that hazelnut has maintained a consistent niche space over the past 11,000 years before present. However, the limitations of fossil pollen data created less certainty in these results. Future work involves testing this framework on additional species to determine if these patterns are consistent across woody taxa, as well as testing if land cover datasets that are more categorically resolved and include human impacts are able to improve distribution models.
Open Access
Ground beetle conservation biocontrol: Potential for pest control ecosystem services using predation activity and trait-based analysis
(2023-12-08) Neame, Tobyn J.; Galpern, Paul; Summers, Mindi; Ciborowski, Jan
Removal of non-crop vegetation (e.g., forest and grassland patches) to expand crop fields threatens the natural enemies of crop pests, like the ground beetle family (Coleoptera: Carabidae), that may use these areas for overwintering. An argument for maintaining non-crop vegetation is its potential to support the supply of ecosystem services, such as pest control, to the surrounding crop. A common proxy for this service is the activity-density of natural enemy species. Evidence that predators like ground beetles are attacking pests in crops has been less frequently studied as have the mechanisms for why non-crop vegetation may influence pest predation within the crop. Studying the traits of natural enemies that are both impacted by the environment and affect their predation activity, may provide a mechanism for how non-crop vegetation influences pest control. Traits, like the size of carabids, may influence both their dispersal from non-crop vegetation and their predatory activity. I sampled a gradient of distances from non-crop vegetation in 20 field sites. I estimated the potential for pest attacks by carabids through bite marks on sentinel prey (plasticine ‘caterpillars’ made to look like potential prey items) and measured the body size of 20,407 carabids. I also conducted prey choice experiments with the carabid Pterostichus melanarius. Generalized additive models show that the frequency of bite marks increased to 50 m into the crop before declining at 100 m, but carabids in pitfall traps increased linearly as distance from non-crop vegetation increased. Results also showed the smallest six quantiles of carabids increased in size with distance from non-crop vegetation areas and larger P. melanarius showed a trend towards preying upon larger prey than smaller prey, though we could not reject a null hypothesis of no effect (alpha=0.05; P=0.08). These findings show predation activity may be associated with non-crop vegetation and the carabid community size distribution, rather than being predicted by activity-density. These findings support conservation of non-crop vegetation to support the predation of a diverse array of pests.
Open Access
Growth, Mortality, and Genetic Structure: Effects of Harvest and Management Strategies on Walleye (Sander vitreus) Populations in Alberta, Canada.
(2016) Allen, Brandon; Rogers, Sean; Reid, Mary; Spencer, Stephen; Galpern, Paul
Managed populations exhibit different phenotypic and genetic signatures from their natural counterparts. Walleye (Sander vitreus) are a heavily managed species recovering from population collapse in Alberta, Canada. In my thesis, I examined the effects of harvest on growth, mortality, and genetic structure. First, I used 8200 individuals to test associations between growth curves, lake characteristics and management strategies. Second, I used 17,763 individuals to determine how population mortality rates vary between management strategies. Third, I assessed the genetic population structure for seven populations and differences in genetic variation between the 1970s and 2000s. I found that growth rates were associated with certain lake characteristics, including management strategies, and mortality rates did not vary between strategies. I observed a substantial loss of genetic diversity between the 1970s and 2000s, which supports reports of population collapse. My results illustrate the effects of harvest on phenotypic and genetic diversity in managed populations.
Open Access
Habitat Use by Boreal Mammals in Response to Salvage Logging After an Insect Outbreak
(2018-06-20) Thomas, Julie; Reid, Mary L.; Barclay, Robert Malcolm Ruthven; Galpern, Paul; Harder, Lawrence D.
Post-disturbance logging (i.e., salvage logging) is controversial, as it may disrupt forest succession and alter wildlife habitat. I examined habitat use by moose (Alces americanus), snowshoe hares (Lepus americanus), lynx (Lynx canadensis), coyotes (Canis latrans), and little brown bats (Myotis lucifugus) in response to salvage logging after a bark beetle outbreak in Yukon, Canada. I monitored species occupancy in beetle-affected forests and salvage-logged stands of different tree retention levels and ages using wildlife cameras and bat detectors. Moose occupancy was highest in low-retention-logged stands with low cover and abundant shrubs. Snowshoe hares occupied stands with dense canopies and avoided logged stands (regardless of retention or age); lynx and coyote used similar habitat to hares. Logging had no significant effect on little brown bats, although bats avoided densely-treed stands. Diverse forest management strategies may benefit the most species, including salvage logging with variable retention and maintaining patches of beetle-affected forest.
Open Access
How Landscape Filters Local Abundance: A Test of the Body Size-Foraging Range Hypothesis in Bumble Bees
(2018-03-09) Retzlaff, Jennifer Leigh; Galpern, Paul; Cartar, Ralph Victor; Bender, Darren J.; Flanagan, Kyla M.; Pavelka, Mary McDonald
For central place foragers, foraging range increases with body size. This is true for eusocial pollinators such as bumble bees, for whom body size dictates the maximum distance to which foragers can travel from their nest. Body size should therefore influence the size of landscape over which floral resources are accessible, and indirectly affect local abundance. Given this dispersal constraint, landscape should be an environmental filter for bees based on their body size, resulting in a size-based distribution of abundances in the local bee community reflecting the distance-based availability of resources. In this way, the abundance of bumble bees should reflect landscape composition. I found that the abundance of queens in Southern Alberta was related to an interaction between the amount of semi-natural land cover (a measure of foraging resources for bees) at two spatial scales: near the nest (local; 0 – 500 m) and further afield (broad; 500 – 2000 m). Small queens were more abundant when local availability of semi-natural land was moderate or high, and broad availability of semi-natural land was at low or moderate. The converse was not true: large queens were not more abundant when local resources were poor, and broad resources high. Worker abundance increased with local semi-natural land cover, but surprisingly showed no sign of this relationship being mediated by body size, suggesting that landscape composition influences the body size composition of bumble bee communities primarily during the nest establishment phase by queens. I conclude that the body size-foraging range hypothesis is generally unsupported in my system, but the hypothesis received partial support in the case of small-bodied queen bumble bees being more abundant when amount of local semi-natural habitat was high.
Open Access
Impacts of Lake Physical Characteristics and the Presence of a Non-native Species on Diet Specialization in Threespine Stickleback (Gasterosteus aculeatus)
(2018-09-21) Curley, Douglas Taylor; Vamosi, Steven M.; Vamosi, Jana C.; Galpern, Paul; Wasmuth, James D.
The diet and dietary morphological adaptations of populations have been shown to be influenced by both the physical characteristics of their habitat and the presence of non-native species. In this study, I assessed how diet varies within and among populations of threespine stickleback (Gasterosteus aculeatus) in lakes with varying bathymetry in southwestern British Columbia. These lakes also differed in whether they contained the invasive signal crayfish (Pacifastacus leniusculus). Diet was evaluated through gut content analysis. I also investigated how morphology differs between these populations, as morphology has been shown to be linked to diet in stickleback. Diet data did not reveal any significant differences in diet among populations. However, morphology data did reveal significant differences among lakes and between crayfish conditions. The data suggest that diets higher in benthic invertebrates are associated with lakes with more littoral area and with the presence of signal crayfish.
Open Access
Intraspecific Diversity and the Evolutionary Ecology of Competitive Coexistence: Experiments with Bruchid Beetles
(2015-12-15) Hausch, Stephen; Fox, Jeremy; Vamosi, Steven; Harder, Lawrence; Post, John; Galpern, Paul; Vellend, Mark
Understanding the mechanisms by which competing species coexist is fundamental to explaining nature’s biodiversity. One hypothesis is that intraspecific diversity promotes species coexistence. A number of ecological and evolutionary mechanisms have been identified through which intraspecific diversity can generate stabilizing mechanisms, those that increase the negative frequency-dependence of population growth. However, intraspecific diversity, can also increase a species’ competitive ability through a number of ecological and evolutionary mechanisms, altering equalizing mechanisms and potentially destabilizing coexistence. Modern coexistence theory provides a framework for understanding how these two suites of mechanisms interact: decreases in equalizing mechanisms must be compensated for by increases in stabilizing mechanisms to maintain the stability of coexistence. In this thesis, I explore how intraspecific diversity affects stabilizing and equalizing mechanisms using a classic subject of competition and coevolution studies, bruchid beetles (Callosobruchus spp.). I explored the ecological consequences of intraspecific diversity for coexistence by assaying the coexistence (mutual invasibility) of populations of two competing species (Callosobruchus maculatus and C. chinensis) when each comprised one, three, or five genetically- and phenotypically-distinct lineages. Populations composed of five lineages were then experimentally evolved in sympatry or allopatry to explore the evolutionary consequences of intraspecific diversity. Through periodic assays of life-history traits I tested for ecological character displacement. After assaying each population’s phenotype, I assayed population-pairs for mutual-invasibility to explore how adaptive evolution alters species coexistence. In both the short- and long-term, intraspecific diversity often inhibited coexistence, rather than promoting it. Intraspecific diversity promoted both ecological and evolutionary stabilizing mechanisms, but often had a negative effect on equalizing mechanisms. Intraspecific diversity increased species’ competitive abilities through a combination of ecological (e.g., niche complementarity) and evolutionary (e.g., selection effects) mechanisms. Similar increases in competitive ability by coexisting species maintained fitness equality and strengthened coexistence, due to a strengthening of stabilizing mechanisms, as predicted. However, species often experienced different gains in competitive ability, destabilizing coexistence. I review the mechanisms by which intraspecific diversity alters equalizing mechanisms and identify a need to better understand how these mechanisms interact.
Open Access
Landscape composition and configuration affect nest founding but not success of bumble bee colonies in agroecosystems in the Lower Mainland of British Columbia, Canada.
(2021-04-27) Kwafo, Richard; Galpern, Paul; Cartar, Ralph; Vamosi, Jana; Post, John
Landscape structure influenced by land-use is likely to affect pollinator demography. Using naturally colonized nest boxes placed at 27 sites in the Lower Mainland of British Columbia, I assessed demographic responses of bumble bees to the availability of resources as inferred from landscape structure (i.e., landscape composition and configuration), and examined the spatial scale that best explained responses to the landscape. I used mixed model regression analysis to model the influence of semi-natural habitat, beneficial agriculture, suburban cover, and habitat edge density, all measured in six radii (250 m - 2500 m) around colonies, on nest founding and success of bumble bee colonies. Semi-natural habitat had no relationship with nest founding and colony success. Nest founding decreased in surroundings with more “beneficial agriculture” cover (i.e., mass flowering berry crops), however, nest founding increased at locations with more edge habitats. Higher amount of suburban cover decreased nest founding. Nest founding was best explained by the landscape at a 1500 m radius around the nest, however, there was no evidence of colony success responding to the landscape at any spatial scale. I conclude that beneficial agriculture and suburban cover had negative consequences for nest founding in bumble bee populations within my study landscape. Edge habitats seemed to attract more bumble bee queens to nest and may maintain bee populations while serving as sources of wild bumble bee pollinators, who might forage within nearby commercial blueberry crops to improve crop yield.
Open Access
Making Movement Matter: Modelling Connectivity with Spatial Interaction Models
(2018-07-10) Koenig, Shantel Julene; Bender, Darren J.; Bertazzon, Stefania; Galpern, Paul; Alexander, Shelley M.
While the idea of landscape connectivity is conceptually straightforward, practically assessing connectivity is substantially more complicated. Behavioural interactions and the composition and configuration of the landscape ultimately determine an animal’s movement between locations; however, when it comes to modelling connectivity, the comprehensive integration of these key determinants into models is lacking. Interestingly, models used by geographers to model human movement and connectivity are centered on the similar key themes of composition and configuration, but also incorporate the components commonly missing in ecological connectivity models. Specifically, spatial interaction models (SIMs) include variables to describe locational traits and offer a model structure that can account for many of the factors that may influence movement across the landscape. Therefore, the aim of this dissertation was to examine to what extent the SIM framework could be adapted and applied to more fully model landscape connectivity. Using both theoretical and empirical approaches, connectivity modelling using SIMs was explored in several ways. A simulation-based study explored the effect that matrix generalization has on assessments of connectivity at both the landscape and patch scale. As well, the ability of SIMs to model the movement landscape was explored using a simulation model and a case study on Ord’s kangaroo rat, and methods for interpreting and assessing model outputs were developed and presented. Overall, SIMs were successful at assessing connectivity and provided new insights into how connectivity varies across landscape and patch scales. SIM outputs showed that as connectivity models were varied, there were no consistent trends or patterns in the differences in assessments, suggesting that connectivity assessments can be highly sensitive to the landscape representation and the model inputs used. Especially when there is uncertainty in the landscape representation or in understanding how a species interacts with the landscape during movement, uncertainty analysis is required, and SIMs provide a meaningful way to do so. Ultimately, and overall, SIMs proved to be a useful, straightforward, and flexible way to model connectivity, especially in cases that warrant incorporating more information than just distance and patch area.
Open Access
Pollination Responses to Introduced Plants and an Elevation Gradient in Camas Dominated Wet Meadows
(2024-01-01) Rampton, Rowan W.; Galpern, Paul; Vamosi, Jana; Summers, Mindi
Global change is driving declines in insect biodiversity, with widespread consequences for ecosystem function. Climate change and invasive species are key global change factors, but the ways in which they alter pollination are poorly understood in many systems. Camas meadows occur in the southwestern-most areas of Canada, where they support high floral and pollinator diversity, yet we know little about the pollination ecology of these meadows, let alone how they are impacted by aspects of global change. My objectives in this thesis were to evaluate evidence that camas meadows are experiencing impacts related to climate change and plant invasions. I used a pollen limitation experiment conducted across an elevation gradient to evaluate whether variation in climate generates phenological asynchrony between camas and its pollinators, and used plant-pollinator network analysis to examine whether introduced plants were driving changes in pollination networks. I found that there was no evidence for phenological asynchrony, though camas reproduction was slightly limited by pollen at low elevations, while overall seed production declined as camas approached its elevational limit. Introduced species did not alter network structure, but when removed from networks they had come to dominate, networks were less able to resist further species loss. This suggests that if maintaining pollination is desired, invasive species management decisions should consider the risks associated with losing the floral resources they seek to control. My results describe a system which in its current state, appears robust to the aspects of global change examined (i.e., phenological disturbance and plant invasion) but may be sensitive to further disruption, particularly the removal of abundant introduced plants that pollinators have come to rely upon.
Open Access
Restoration for Wild Bee Community Recovery in the Prairie Pothole Region
(2021-05-03) Purvis, Emily Elizabeth Nan; Galpern, Paul; Vamosi, Jana; Summers, Mindi
Agricultural intensification is a widespread driver of global pollinator decline, which can subsequently threaten the ecosystem services provided to flowering food crops and wild vegetation species. In North America's Prairie Pothole Region, wetlands surrounded by grassland were once abundant on the landscape, but now generally exist within a matrix of agriculture. I assessed whether restoration of these grassland-wetland complexes from cropland could be used as a tool for mitigating wild bee decline and monitored the development of bee nesting and food resources to establish the mechanisms that drive return to a restored habitat. My objective was to determine if restored communities could resemble a reference state (i.e. remnant grassland-wetland complexes) over a 25-year period. I also observed plant-pollinator interactions and used a model-based approach to determine which plant species supported the highest diversity of wild bees, with the objective of identifying beneficial flowering plants to include in future restorations designed to increase the availability of flowering plants. I found bee diversity increased following restoration and approximated reference sites after 1–4 years. Analyses for bumble bees (Bombus spp.) and other bee species separately demonstrated that the latter group was slower to recover, and resembled reference sites after around 5–10 years. Floral diversity also increased following restoration from cropland but remained slightly lower than reference sites through time. Flower species composition was most important for explaining bee species composition, while time since restoration was comparatively less important. From plant-pollinator interactions, I identified 16 plant species from eight families that supported the highest diversity of bees, including Bombus terricola, a species at risk. In general, Fabaceae species were more popular with bumble bees, while a greater variety of plant families supported non-Bombus bees. My results highlight a potential pathway to improve restoration for wild bee conservation in this region by including specific flowering plants. They also underscore the utility of restored grassland-wetland complexes for providing food and nesting resources to bees within agriculturally dominated landscapes and suggest that restoration can recover wild bee communities to a reference state.
Open Access
Roosting behaviour of little brown bats (Myotis lucifugus) in the Canadian Rocky Mountains
(2022-05-08) Micalizzi, Emma; Barclay, Robert MR; Galpern, Paul; Forshner, Anne
Little brown bats (Myotis lucifugus) are highly adaptable bats that occur throughout most of North America. The presence of reproductive individuals in northern and mountainous environments is surprising, however, as small, volant, insectivorous mammals should face many challenges to surviving and reproducing in regions with short, cool summers. The objective of my research was to examine the roosting ecology of female little brown bats in Banff and Yoho National Parks, with a focus on the relative importance of building and natural roosts, to help understand how populations persist in the Canadian Rocky Mountains. Better understanding little brown bat ecology is also important given the endangered listing of this species in Canada and by the IUCN.Over two summers, I captured little brown bats at varying distances from buildings, and tracked 49 females to their day roosts. Buildings were the dominant roost type used throughout the reproductive period, and the only structures in which bats formed maternity colonies. Building roosts were particularly relied on by bats in May and June, and by lactating bats. Bats monitored in building roosts were often warmer than those in natural roosts, suggesting that the benefits of building roosts are their warm microclimates. Buildings also appeared to shape the distribution of female little brown bats; reproductive females remained near building clusters, and all females remained near municipalities. Despite the apparent importance of building roosts, building colonies were unusually small, and bats had relatively low fidelity to building roosts, suggesting that building roosts may not consistently meet bats’ needs. Some non-reproductive and pregnant females also frequently used natural roosts, particularly after colder nights. This, combined with bats’ lower skin temperature in natural roosts, points to an importance of natural roosts in facilitating torpor. My results suggest that little brown bats may successfully reproduce in cold environments by relying on warm building roosts. However, natural roosts are likely important in allowing pregnant bats and non-reproductive bats to save energy. Because bats are long-lived with low reproductive output and low juvenile survival, the survival of both reproductive and non-reproductive individuals is important for population stability.
Open Access
Roosting Ecology and Behaviour of Small-footed Bats (Myotis ciliolabrum) and Presence of Bats in Winter in Dinosaur Provincial Park, Alberta
(2017) Findlay, Stephanie; Barclay, Robert; Cartar, Ralph; Galpern, Paul; Theodor, Jessica
I studied roosting behaviours of western small-footed bats (Myotis ciliolabrum) in Dinosaur Provincial Park, a semi-arid badland region in Alberta. Individuals roosted solely in the prevalent erosion-holes within the park. Regardless of sex or reproductive condition, M. ciliolabrum exhibited low roost fidelity but high fidelity to coulees. Individuals selected roosts which were high off the ground with an internal microclimate significantly buffered from external conditions, with depth not affecting roost buffering capacity. I also measured the effect of habitat on the echolocation calls for three Myotis species within the coulees and along tree edges. Myotis lucifugus and Myotis ciliolabrum significantly alter their calls between the two habitat types. Using local calls to construct a call library allowed me to determine that both M. ciliolabrum and M. evotis were present over winter. The higher proportion of M. evotis activity may be explained by gleaning insects during warmer periods.
Open Access
Scaling of Density-Dependent Reproduction in Bee-Pollinated Forbs of Logged Forests
(2015-12-16) Johnson, Sarah A.; Cartar, Ralph; Vamosi, Jana; Ruckstuhl, Kathreen; Galpern, Paul; Goldblum, David
Plant reproduction can be impacted by a variety of influences at a range of spatial scales. In the face of accelerating anthropogenic habitat disturbance, it is worth understanding how communities function within highly altered landscapes. I examined how seed size and number varied for nine species of understory forb within logged foothills forests of southern Alberta. I examined local relationships between reproductive output and floral neighbourhood, bee abundance, and habitat variation, and how these might be modified along a gradient of landscape-scale clearcut logging. I found that local variables best explained plant seed production, and heterospecifics were generally more beneficial than expected. Further, logging in the landscape modified local interactions above a threshold point of approximately 50% logging in a 1.77 km^2 area, predominantly for more habitat-specialized species. These results have implications for forest management, and for the importance of testing for interactions between explanatory variables, even across spatial scales.
Open Access
Simulation of protected area and forestry cutblock design in the boreal plain ecoregion
(2017) Fauvelle, Catherine; Galpern, Paul; Tyler, Mary Ellen; Alexander, Shelley
Spatial and statistical analyses are becoming more commonplace in planning for conservation and land-use programs. I used specific spatial and statistical analyses to examine their potential for answering questions posed by stakeholders in the boreal plain ecoregion regarding the strategic placement of protected areas and forestry cutblocks on the retention of ecological integrity. I found that neither strategic placement nor size significantly affect the retention of ecological integrity within protected areas. Additionally, I found that clustering new forestry cutblocks near existing disturbances did not significantly affect the loss of connectivity, though doubling the expected area of harvest did increase the loss of certain connectivity metrics. The conclusions drawn from this thesis are relevant to landscape planners and conservation managers, but should be paired with the results of biological studies to better represent the reality of complex ecosystems.
Open Access
Spatial Synchrony of Predator-Prey Dynamics in Response to Cyclic Temperature Fluctuations
(2021-09-21) Osterlund, Kaitlin Breanne; Fox, Jeremy; Reid, Mary; Galpern, Paul
Spatial synchrony in populations occurs for many species, but is most apparent for species with populations that experience cyclic fluctuations. Population cycles can enhance the strength of synchrony-producing mechanisms by phase-locking cycles through dispersal events, or by entraining cycles to local cyclic environmental perturbations. Comparative evidence shows that density-dependent population regulation can differ spatially based on local environmental fluctuations that drive synchrony, but there is a lack of empirical evidence to further support this mechanism. This study looked to determine whether population cycles and cyclic environmental fluctuations impact the occurrence and persistence of spatial synchrony. A literature review was conducted that supported the relation between spatial synchrony and population cycles. A Rosenzweig-MacArthur model with oscillating density dependence was produced to establish expected results for empirical tests. Patches of microcosm jars were then cycled between different temperatures to create environmental perturbations on model protist species Tetrahymena pyriformis and Euplotes patella which generate predator-prey cycles. The population cycles were manipulated by varying media enrichment and temperature cycle period length to establish a threshold synchrony range. Model results show that spatial synchrony occurs at high amplitude cyclic environmental fluctuations with cycle periods that closely match to the cycle period of the populations that are being synchronized. Due to COVID-19 restrictions, the experiment could not be carried out as initially intended, and results reflect the limitations imposed. Results suggested by the model could not be replicated experimentally. Future directions are suggested for studies with no pandemic-related restrictions.
Open Access
SPATIOTEMPORAL FACTORS INFLUENCING THE DISTRIBUTION AND ABUNDANCE OF GRIZZLY BEARS (URSUS ARCTOS) INHABITING THE BARREN-GROUNDS OF THE CENTRAL CANADIAN ARCTIC
(2017) Jessen, Tyler; Musiani, Marco; Galpern, Paul; Massolo, Alessandro; McDermid, Greg
Spatially-explicit capture-recapture (SCR) methods can be used for estimating animal density and testing biogeographic hypotheses about the influence of landscape heterogeneity on animal space use. I used SCR to estimate the density of grizzly bears inhabiting the tundra of the central Canadian Arctic and extended the SCR framework to estimate their multi-scale habitat selection in relation to the spatiotemporal variation of food sources. Grizzly bear density was estimated to be 4.56 bears/1,000km2, which is slightly higher than estimates from 15-20 years ago. Berries and the spatial distribution of migratory caribou had the largest effect on the large scale selection patterns of bears. Food abundance had less of an effect on the resource selection of grizzlies within their home ranges. The results of this thesis indicate that grizzly bear density in the tundra is dependent upon food sources, with other factors such as intraspecific competition governing finer-scale selection patterns.