Davy, Christina

Northern flying squirrels (NFS) are mycophagous specialists (fungi-dominated diet) thatmay be displaced with southern flying squirrel (SFS) range expansion, thereby limiting fungal dispersal in forest communities. To understand the implications of squirrel species turnover on mycophagy, we investigated the home ranges of both flying squirrel species who are living in stable sympatry. We found no significant difference in home range sizes and identified spatial overlap between the two species. Through habitat selection ratios we found SFS were strongly selecting for deciduous-dominated habitats more than NFS. Lastly, we conducted microscopy on flying squirrel scat and found NFS were eating more fungi than SFS. We conclude that the squirrels are sharing the same habitat landscape but are finding ways to partition the habitat accordingly to allow for sympatry. SFS may contribute to the spore-dispersal cycle similarly to their northern counterpart through moderate fungus consumption and large home range sizes.

Author Keywords: diet, flying squirrels, Glaucomys, home range, mycophagy, sympatry

I used 31 years of Semipalmated Plover (Charadrius semipalmatus) population data to assess the effects of vital rates on a local breeding population of plovers in Churchill, Manitoba, Canada. I used three similar Bayesian Integrated Population Models (IPMs), with the last a coupled IPM population viability analysis (PVA) approach to predict the impact of changing spring temperatures on future population size. I estimated adult and juvenile apparent survival, fecundity, immigration rate, and yearly population size estimates, and I found that population growth rate was most highly correlated with immigration and adult apparent survival. Moreover, I found that the population remained relatively stationary with a slight decline in recent years. I also found a significant positive effect of spring average daily minimum temperature on juvenile apparent survival. I used this effect to inform my PVA and to evaluate the risk of quasi-extinction for 20 years after the end of the study. I found a low quasi-extinction risk and a greater probability of the population increasing in the next twenty years when informed by predicted spring temperatures from global climate models. My findings suggest some resilience of this species to one effect of climate change and emphasize the importance of continued monitoring to assess if declines in this species will change as multiple threats to their existence in the sub-arctic progress.

Author Keywords: Bayesian, Climate change, Integrated population model, Population dynamics, Population viability, Semipalmated Plover

Globally, fledglings of more than 50 seabird species are vulnerable to stranding in human settlements near their colonies as they leave their nests for the first time. This phenomenon has been attributed to attraction toward and disorientation by artificial light at night (ALAN). Grassroots rescue programs find more birds in illuminated locations than in dark ones, but it is unclear to what extent this pattern is driven by seabird versus rescuer behaviour. I studied behavioural responses to ALAN in stranding-prone Atlantic puffin (Fratercula arctica) and Leach's storm-petrel (Hydrobates leucorhous) fledglings and investigated detection probabilities of 3D-printed puffin fledgling decoys by rescuers. I hypothesized that seabird strandings are due to attraction toward ALAN; that post-stranding behaviour varies with taxon and lighting conditions; and that post-stranding behaviour (e.g., concealment) and lighting conditions drive variance in detection probability of stranded seabirds by rescuers. To address my first hypothesis, I alternately illuminated two beaches near a Newfoundland puffin colony and found significantly more puffin fledglings stranded when the beaches were illuminated than when they were dark, supporting the light attraction hypothesis. Stranded puffins similarly moved toward light over darkness in a Y-maze choice experiment and were less active under LED light than in darkness or under high-pressure sodium light, demonstrating a preference toward certain light conditions post-stranding. In contrast, storm-petrels predominantly avoided lit conditions in a Y-maze and were less active in darkness than under light. Further, when provided with a place to hide, more than half of storm-petrels concealed themselves when in light conditions versus none in darkness. To test my third hypothesis, I deployed puffin decoys and found that rescuers detected them more easily in higher light levels, in less concealed locations, and with increased search effort. My results support historical deductions that seabird fledgling strandings are caused by attraction toward artificial light but demonstrate that post-stranding behavioural responses to ALAN depend on species and light type, which may in turn affect detection probability by rescuers.

Author Keywords: artificial light, atlantic puffin, charadriiform, Leach's storm-petrel, light attraction, procellariiform

Northern flying squirrels (NFS) are mycophagous specialists (fungi-dominated diet) thatmay be displaced with southern flying squirrel (SFS) range expansion, thereby limiting fungal dispersal in forest communities. To understand the implications of squirrel species turnover on mycophagy, we investigated the home ranges of both flying squirrel species who are living in stable sympatry. We found no significant difference in home range sizes and identified spatial overlap between the two species. Through habitat selection ratios we found SFS were strongly selecting for deciduous-dominated habitats more than NFS. Lastly, we conducted microscopy on flying squirrel scat and found NFS were eating more fungi than SFS. We conclude that the squirrels are sharing the same habitat landscape but are finding ways to partition the habitat accordingly to allow for sympatry. SFS may contribute to the spore-dispersal cycle similarly to their northern counterpart through moderate fungus consumption and large home range sizes.

Author Keywords: diet, flying squirrels, Glaucomys, home range, mycophagy, sympatry

I used 31 years of Semipalmated Plover (Charadrius semipalmatus) population data to assess the effects of vital rates on a local breeding population of plovers in Churchill, Manitoba, Canada. I used three similar Bayesian Integrated Population Models (IPMs), with the last a coupled IPM population viability analysis (PVA) approach to predict the impact of changing spring temperatures on future population size. I estimated adult and juvenile apparent survival, fecundity, immigration rate, and yearly population size estimates, and I found that population growth rate was most highly correlated with immigration and adult apparent survival. Moreover, I found that the population remained relatively stationary with a slight decline in recent years. I also found a significant positive effect of spring average daily minimum temperature on juvenile apparent survival. I used this effect to inform my PVA and to evaluate the risk of quasi-extinction for 20 years after the end of the study. I found a low quasi-extinction risk and a greater probability of the population increasing in the next twenty years when informed by predicted spring temperatures from global climate models. My findings suggest some resilience of this species to one effect of climate change and emphasize the importance of continued monitoring to assess if declines in this species will change as multiple threats to their existence in the sub-arctic progress.

Author Keywords: Bayesian, Climate change, Integrated population model, Population dynamics, Population viability, Semipalmated Plover

White-nose syndrome (WNS) is a skin disease of bats caused by the fungus Pseudogymnoascus destructans (Pd) that damages flight membranes during hibernation and can lead to death. The disease causes mortality of multiple bat species in eastern North America and is spreading into western North America. Future impacts of WNS on naïve bat populations are unknown. Variation in host susceptibility occurs among and within species, but mechanisms driving this variation are unclear. Multiple studies have characterized immunological responses to WNS, but skin physiology as a barrier to pathogens is understudied. The unique ability of Pd to actively penetrate the normal, intact skin of its mammalian host makes WNS an interesting study system to understand skin defenses. Aspects of the mammalian skin environment that can influence disease susceptibility include pH, sebaceous lipids, and microbiomes. I found skin mycobiomes of WNS-susceptible species had significantly lower alpha diversity and abundance compared to bat species resistant to Pd infection. Using these data, I predicted that most naïve bat species in western North America will be susceptible to WNS based on the low diversity of their skin mycobiomes. Some fungi isolated from bat wings inhibited Pd growth in vitro, but only under specific salinity and pH conditions, suggesting the microenvironment on wings can influence microbial interactions and potentially WNS-susceptibility. I measured the wing-skin pH of bats in eastern Canada and found that Eptesicus fuscus (WNS-tolerant) had more acidic skin than M. lucifugus (WNS-susceptible). Differences in sebum quantity and composition among and within mammalian species may help explain variation in skin disease susceptibility and the composition of skin microbiomes. This is due to the antimicrobial properties of sebum and the use of sebum as a nutrition source by microbes. Outcomes of this work further our understanding of inter- and intra-specific differences among bat species and individuals in skin mycobiomes and physiology, which may contribute to variation in WNS-susceptibility. Future research should focus on characterizing the physical and chemical landscape of skin as this is essential for understanding mechanisms structuring skin microbial assemblages and skin disease susceptibility in wildlife.

Author Keywords: bat, fungi, microbiome, mycology, physiology, white-nose syndrome

AbstractDifferences and similarities in exploration and risk-taking behaviours of two Myotis bat species. Laura Michele Scott Behaviours that are repeatable across circumstances and time determine an individual's personality. Personality and behavioural variation are subject to selective pressures, including risks related to the use of different habitat types. I explored the ecological and evolutionary consequences of habitat selection by comparing the behaviour of two sympatric bat species, Myotis leibii and M. lucifugus. These species display overlap in roosting preferences, however, M. leibii tend to roost in crevices on the ground, while M. lucifugus tend to roost in crevices or cavities that are raised off the ground. I hypothesized that the habitat selection patterns of these two species create behavioural reaction norms at the species level. I predicted that ground roosting behaviour favours bolder personality and more exploratory and active traits when compared with bats that do not ground roost. I examined inter- and intra-specific variation in behaviour using a modified, three-dimensional open-field test and quantified the frequency and duration of behaviours such as flying, landing, and crawling. Bats were continuously video-recorded over 1-hour nocturnal and diurnal trials. I used a priori mixed models with combinations of individual characteristics and life-history traits to select the models that best describe each species. We found that M. leibii (n = 15) displayed more exploratory and bolder behaviours than M. lucifugus while on the ground (n = 21) and higher overall activity during the trial. I also found that M. leibii displayed crawling behaviours and movements consistent with foraging while on the ground which is a rare behaviour in bats and only observed in a few species (Desmodus rotundus and Mystacina tuberculate to my knowledge). Future research should explore biomechanical adaptations associated with ground-foraging in M. leibii.

Author Keywords: Bats, Behaviour, Exploration, Myotis leibii, Myotis lucifugus, Roosting

Rapidly changing landscapes introduce challenges for wildlife management, particularly for large mammal populations with long generation times and extensive spatial requirements. Understanding how these populations interact with heterogeneous landscapes aids in predicting responses to further environmental change. In this thesis, I profile American black bears using microsatellite loci and pooled whole-genome sequencing. These data characterize gene flow directionality and functional genetic variation to understand patterns of dispersal and local adaptation; processes key to understanding vulnerability to environmental change. I show dispersal is positively density-dependent, male biased, and influenced by food productivity gradients suggestive of source-sink dynamics. Genomic comparison of bears inhabiting different climate and forest zones identified variation in genes related to the cellular response to starvation and cold. My thesis demonstrates source-sink dynamics and local adaption in black bears. Population management must balance dispersal to sustain declining populations against the risk of maladaptation under future scenarios of environmental change.

Author Keywords: American black bear, Dispersal, Functional Genetic Variation, Gene Flow Directionality, Genomics, Local Adaptation

Human-wildlife interactions are inevitable and lead to decisions about wildlife. The current research investigated what demographic and psychological factors influence decisions in wildlife management. Also, a new measure, the Tolerance for Wildlife Scale, was developed. A student sample (n = 329) and a community sample (n = 213) completed measures on their nature relatedness, environmental concern, and emotions towards wildlife. They completed the Tolerance for Wildlife Scale and rated decisions to use lethal or non-lethal action in nine human-wildlife scenarios. Correlation analyses revealed people who are more tolerant towards wildlife are more connected with nature, concerned for the environment, feel positive emotions towards wildlife, and are more likely to choose non-lethal management actions. ANOVAs revealed that location and occupation have an impact on tolerance for wildlife. By identifying factors that influence tolerance for wildlife, humans can hope to share space with wildlife and foster coexistence.

Author Keywords: emotion, environmental concern, nature relatedness, tolerance, wildlife, wolves

Many rare and elusive species have low detection probabilities, thereby imposing unique challenges to monitoring and conservation. Here, we assess the detection probability of the Eastern Massasauga (Sistrurus catenatus) in contrast to a more common and conspicuous species, the Eastern Gartersnake (Thamnophis sirtalis). We found that patterns of detection probability differed between species, wherein S. catenatus was detected less often and under a more specific set of sampling conditions. Correspondingly, detection trials with S. catenatus found a high non-detection rate, while detection trials with artificial models suggest that regional differences in detection probability are driven by variation in population density and habitat use. Our results suggest that current monitoring efforts are not sufficient, and that S. catenatus is frequently undetected. Accordingly, we highlight the importance of species-specific monitoring protocols when monitoring rare and elusive species, and recommend a multi-faceted approach that estimates detection probability and identifies species-specific challenges to monitoring.

Author Keywords: detection probability, elusive species, monitoring programs, non-detection, S. catenatus, snakes