University of Calgary PRISM: University of Calgary's Digital Repository Graduate Studies The Vault: Electronic Theses and Dissertations 2018-12-19 Habitat Structures Rainbow Trout Population Dynamics Across Spatial Scales Cantin, Ariane Cantin, A. (2018). Habitat Structures Rainbow Trout Population Dynamics Across Spatial Scales (Unpublished doctoral thesis). University of Calgary, Calgary. AB. http://hdl.handle.net/1880/109388 doctoral thesis University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission. Downloaded from PRISM: https://prism.ucalgary.ca UNIVERSITY OF CALGARY Habitat Structures Rainbow Trout Population Dynamics Across Spatial Scales by Ariane Cantin A THESIS SUBMITTED TO THE FACULTY OF GRADUATE STUDIES IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY GRADUATE PROGRAM IN BIOLOGICAL SCIENCES CALGARY, ALBERTA DECEMBER, 2018 © Ariane Cantin 2018 Abstract Density-dependent processes play an important role in structuring population dynamics – as the number of organisms within a set area increases, population vital rates and life history traits will also change arising from increased competition for limited food and space. In this thesis I explore how variation in the quantity of habitat available impacts size-structured animal populations using lake-dwelling rainbow trout (Oncorhynchus mykiss). First, I developed hypotheses on the biological processes by which habitat impacts population dynamics using a multi-habitat age-structured population model. This theoretical model showed that habitat limitations at any life stage can bottleneck the population and impact its dynamics, but that the timing of regulation influences population outcomes. Limited habitat in early life led to high early mortality, resulting in low overall population density of larger fish, while limited habitat in adult life led to high early survival and a high density of stunted fish populations. I then compared the model predictions to empirical data from 39 wild rainbow trout populations and to results of a harvest experiment. The field results corroborated the model predictions and showed that lakes with a higher early (stream) to late (lake) life stage habitat ratio presented higher number of recruits, later age at maturity and a smaller maximum size than lakes in which stream habitat was limiting. The density manipulation also supported the model predictions as the lake with the lowest habitat ratio presented the lowest compensatory reserve and showed a density-dependent growth response to harvest. Finally, I used the knowledge acquired at the lake-scale to predict rainbow trout production at the landscape-scale. I developed a methodology that describes rainbow trout distribution ii based on stream network characteristics and connectivity. Then I used a landscape-scale proxy of stream habitat availability, stream order, and lake area to predict stream to lake habitat ratio and infer population dynamics. I combined this landscape-scale production information with recreational fishing demand to identify regions more prone to being impacted by overfishing or habitat perturbations. My research details how local habitat availability influences fish populations and can be used to predict population dynamics across a landscape of lakes providing a valuable tool to managers. iii Preface This thesis is an original work developed by the author (me), Ariane Cantin. The studies presented were done in collaboration with colleagues at the University of Calgary and fishery scientists and managers from the British Columbia Government and Freshwater Fisheries Society of British Columbia (FFSBC). The contribution from those collaborators is described for each research chapter below. A version of the research conducted in Chapter 2 has been published in the journal Ecology from the Ecological Society of America before the submission of this thesis. It is written with co-author John R. Post, my supervisor at the University of Calgary, and therefore uses “we” instead of the “I” used in the rest of the thesis. The full citation is given in the thesis References section under Cantin and Post (2018). I developed the model presented in this chapter, performed all the analyses and writing. John Post revised my findings and interpretations through discussions and edits to the manuscript. The work presented in Chapter 3 is an empirical study I designed, led, analyzed and wrote. Kyle Wilson (University of Calgary) provided support for the Bayesian statistical analyses. Paul Askey (FFSBC) and John Post (University of Calgary) provided edits to the analyses and earlier versions of the chapter. Chapter 4 is an experiment I designed, led, analyzed and wrote. John Post and Stephanie Mogensen (University of Calgary) provided edits to my analyses and manuscript. iv Chapter 5 is a landscape-scale modelling and application of the local-scale findings from the earlier chapters. I designed and led the study. Anne Farineau (University of Calgary) provided GIS support and conducted preliminary spatial analyses. I was responsible for the final analyses, figures presented and writing of the manuscript. Anne Farineau, Darren Bender and John Post (University of Calgary) provided comments and edits to the analyses and edited the manuscript. v Acknowledgements The studies presented in this thesis were funded by Discovery and Collaborative Research and Development Grants from the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Freshwater Fisheries Society of British Columbia (FFSBC) to John R. Post. I also recognize the financial support of NSERC through a Postgraduate Scholarship, the University of Calgary who awarded me a Silver Anniversary Graduate Fellowship and the British Columbia Provincial Government. I thank my supervisor, John Post, for taking me as his student and guiding me through this project. His hands-off supervisory style made me wonder at times if he would stop me from going in a wrong direction, but, in the end, I recognize that he always had my back and left me enough space to explore and learn on my own while still being completely present when I needed him. I am also thankful for my great supervisory committee, Paul Askey and Darren Bender, for raising important questions about my study design and work that greatly enhanced my project. Paul made me explore the management implications of my work, while Darren helped me situate my findings in a broader spatial scale. I thank colleagues at BC FLNRO (Andrew Klassen, Steve Maricle, Russ Bobrowski, Hillary Ward, Eric Hegerat), FFSBC (Theresa Godin, Kirstin Gale, Marcus Boucher, Adrian Clarke) and BC Environment (Brett van Poorten, Eric Parkinson), that supported me in the development and planning of this project and offered tremendous field assistance. The data presented in this thesis would not have existed without the efforts of Eric Newton and Ron Bowron who were the core field team and spent vi countless hours measuring fish with frozen hands, camping in the snow, driving on endless forestry roads (with the not so occasional flat tire), bushwacking with an electrofisher on their back and generating field stories that I will (for the most part) cherish and tell for many years to come. I also thank Marguerite Tibbles, Katrina Siebert, Adam Hope, Eric Kukulowicz, Sean Boysen and Troy Machovec for their hard work in the field. I thank my lab family: Kyle Wilson, Nilo Sinnatamby, Anne Farineau, Chris Cahill, Jon Mee, Dylan Glaser and Fiona Johnston for their support that came in many forms (field, moral, statistical, pub). I am greatly indebted to two of my labmates, Hillary Ward who mentored me and helped me develop the ideas that became this project, and Steph Mogensen who has supported me and edited pretty much everything I’ve written in my “improving but still far from perfect” English in the past four years (not a small task!). I want to give a special “remerciement” to my dear friend and colleague Pascale Gibeau who has been an almost daily virtual presence throughout this project and who many years ago gave me my first biology job. I must also thank fellow members of the University of Calgary Biological Sciences Department for the great memories and friendships made, particularly but not limited to: Ella Bowles, Louise Hahn, Emma Carroll and Analisa Lazaro-Côté. My final thanks go to my friends and family who have encouraged me, took me skiing, made me dinner and listened to me throughout the completion of my degree even though they probably didn’t (or still don’t) understand what I’m doing or why I’m freaking out. I am particularly grateful to my husband Jay and my parents Serge and Lorraine. Merci ! vii Table of Contents Abstract .............................................................................................................................. ii Preface ............................................................................................................................... iv Acknowledgements .......................................................................................................... vi Table of Contents ........................................................................................................... viii List of Tables ...................................................................................................................