Grant: Discovery Grants Program - Individual

The environment is rapidly changing due to a variety of human pressures, and we still largely lack the ability to predict why some animals have the capacity to persist in altered habitats while others do not. Without this information, it is difficult to prioritize conservation actions and targets under often-limited resources. Although the toolbox we can access for measuring how individual animals respond to stressors is extensive, physiology and behaviour represent the most rapidly responding metrics. As a result, measurements of physiology and behaviour have the potential to allow us to gauge how populations will change in advance of when the consequences manifest as declines. To understand how physiological measures can be used in this context, their relationship to the fitness metrics that drive population change, including reproductive success and survival, must be established. With a team of graduate and undergraduate students, I will conduct research aimed at understanding when and how glucocorticoids (i.e., cortisol and corticosterone; primary hormones involved in animal responses to stressors) are linked to fitness. We are using a combination of observational and experimental approaches to study glucocorticoid-fitness relationships in both birds and fish: Tree Swallows and Bluegill, respectively. Our research will test several hypotheses of how changes in glucocorticoids may influence reproductive success and survival, while addressing multiple gaps that have contributed to inconsistencies across studies in the past. First, we are examining glucocorticoid-fitness relationships in multi-stressor environments, which are expected to increase as novel stressors become more common. Second, we are considering how underlying contexts such as sex, environmental quality, and type and frequency of stressors can change how individuals respond and, in turn, how this can alter the relationship between glucocorticoids and fitness. Finally, we are investigating whether multi-metric approaches (i.e., measuring multiple physiological and behavioural metrics simultaneously) impart more clarity than interpreting glucocorticoid levels in isolation. This research will enhance our insight into the potential for glucocorticoids to be shaped by selection while also increasing our ability to understand whether, through regulation of physiology, organisms possess the adaptive capacity to respond to habitat alteration. The proposed studies are essential to determining whether glucocorticoids are useful as tools to assess threats, monitor disturbance, and/or evaluate the success of conservation interventions. This research will also train a diverse set of Canadian scientists that can transition to careers that contribute to solving the global biodiversity crisis.