PhD Student University of Guelph Guelph, Ontario, Canada
Abstract: As the fastest growing habitat type on the planet, urban environments encroach upon existing ecosystems and habitats at a pace never seen before, yet the severity and implications of these alterations are greatly unexplored. One means through which we may gain insight on the impact of urbanization on wildlife is the hypothalamic-pituitary-adrenal (HPA) axis, a mechanism that connects organisms with their environment via the stress response and glucocorticoid (GC) production. Furthermore, the multi-generational impact of living in an urban setting may be revealed through the examination of maternal effects, and how a mother’s stress, in response to urban stimuli, shapes offspring neurological development, specifically neurogenesis. Eastern grey squirrels (Sciurus carolinensis) are abundant throughout urban and habitats, making them a fitting representative population, for both their success in these environments and their reliance on neurogenesis, an integral part of their caching behaviour. Using urban and natural populations, this study applies a comparative approach to investigate physiological trade-offs of an urban lifestyle in grey squirrels. Through methods including hormone challenges, and immunohistology tissue staining, this study examines the stress of mothers and offspring, and the impact on the rates of neurogenesis in juveniles from both habitats. Preliminary results reveal that long term GC production (found in hair and fecal cortisol) may be similar between populations but short-term reactions to environmental stressors may differ (found in hormone challenges). By testing novel theories related to the ecological and physiological outcomes of environmental stress, this research helps illuminate the specific mechanisms that are influenced by rapid, anthropogenic, environmental changes and moreover, contribute to the development of conservation strategies associated with modified landscapes.
