Feedback mechanisms between ecosystem change, fish behaviour and metabolism

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The ecosystem services that people draw from freshwater lakes in Canada—recreation, fishing and irrigation, to name a few—can also cause stress on the aquatic communities that we draw those services from. These impacts may interact with each other, or with other forms of background stress (e.g., climate change) in unexpected ways. Accurately measuring how freshwater ecosystems respond to stress, and clearly understanding the ways in which specific stress factors act on ecosystems (and how stressors interact with one another) are key steps towards the long-term sustainable management of these vital ecosystems. A better understanding of how environmental stress impacts ecosystems, and the amount and types of stress aquatic ecosystems can tolerate, will put policy makers and resource managers in a better position to protect our essential freshwater resources while ensuring that they continue to provide the services we enjoy in a rapidly changing environment. ****The link between community structure and ecosystem function, or how quickly and what path energy takes as it moves through the food webs, remains an understudied area of ecological research. It is however becoming clear that in many cases, the behaviour of aquatic animals may help to explain some of the variability we observe in how efficiently energy is transferred from one trophic level of the food web to the next. ***Our research program seeks to reveal how structural changes in aquatic animal communities affect ecosystem function and energetic pathways. Our ultimate goal is to advance knowledge in the fields of fisheries biology, food web ecology, community ecology and bioenergetics, and to use the information we gain to help improve sustainable resource management of our freshwaters for future generations.***During the next five years of my NSERC Discovery Grant Program, I will lead my research group to more clearly illustrate the contribution of fish behaviour and metabolism to variation in energy transfer rates in Canadian freshwater lakes. We will address this objective using two complementary approaches. First, we will develop ecological models to take advantage of extensive long-term data and archived tissue collections of freshwater organisms from the world-class IISD-Experimental Lakes Area; this will allow us to model fish behaviour and metabolism over the course of decades through both whole ecosystem experiments and climate change, and will allow us to evaluate how important those changes are and how they may interact to alter fish behaviour and energy flow through these ecosystems. Second, we will develop and carry out a series of experimental and comparative lab and field-based ecological studies to evaluate and identify how fish behaviour differs among lakes that vary or change in specific ways, and relate those changes to vital rates of fish growth, density, reproduction and mortality.**