CHIRONOMID AUTOECOLOGY OF THE PAST AND PRESENT, AND A CAUSAL ANALYSIS OF RECREATIONAL SHORELINE DEVELOPMENTS ON HYPOLIMNETIC OXYGEN IN ALGONQUIN PARK LAKES CAIT CAREW A THESIS SUBMITTED TO THE FACULTY OF GRADUATE STUDIES IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE GRADUATE PROGRAM IN BIOLOGY, YORK UNIVERSITY, TORONTO, ONTARIO MARCH 2020 © CAIT CAREW, 2020 Abstract Recreational cottages continue to be leased within Algonquin Park despite inadequate assessments of cottage impacts on lake water quality and ecosystem integrity. Cottages can increase phosphorus export to lakes, resulting in increased productivity and declines in hypolimnetic oxygen. Algonquin Park lakes contain dense populations of lake trout (Salvelinus namaycush) and brook trout (Salvelinus fontinalis), which are sensitive to declining hypolimnetic oxygen. Dipteran subfossil remains were used to calibrate a VWHO inference model (RMSEP = -1 1.7 mg O2 L ) to determine baseline VWHO (historical, pre-European settlement, < ca. 1850 CE) and assess VWHO change since then using a top-bottom paleolimnological approach. Despite increased anthropogenic activity in the park, inferred VWHO did not change predictably since circa 1850. We did not detect a significant effect of cottages on VWHO. However, regional declines in phosphorus export may be responsible for muting the effects of anthropogenic phosphorus inputs on VWHO in Algonquin Park lakes. ii Acknowledgements Here, acknowledge those who assisted me, in some way, along my path to completing this thesis. First, I would like to thank my supervisor, Roberto Quinlan, you have been an incredible support since we met many years ago. I am grateful to have had this opportunity to learn from such a kind and ‘always’ funny individual. I would like to acknowledge Taly Drezner, for agreeing to be on my committee for a second time. I have appreciated the open lines of communication and the advice along the way! Thanks to Bridget Stutchbury for the support, both on an academic level, and on a personal one. You have given me a lot in a short period of time and your guidance and assistance have been so important, especially during the hard times. To Sapna Sharma, thank you for agreeing so eagerly to participate on my committee and for your advice to make friends with my peers instead of keeping to myself and focusing only on my work. More importantly, I am extremely grateful to have you in a supervisory role in Roberto’s absence, the additional time and effort you have put in has been so helpful. With that, I would also like to thank Amro Zayed for the honorary Master’s degree he awarded me for my dedication to his lab, but more importantly, for his participation on my defense committee. Although not an exhaustive list, I am grateful for the support I’ve received from my York friends, namely, Nick Tulsiram, Katherine Triglav, Tanushree Tiwari, Arshad Imrit, and Brad Auger. To Stephen Rose, thank you for all the help, from idea bouncing to analysis execution, and for the long conversations about topics that confused me. This project would not be what it is without you. Thank you for understanding the struggle and helping me through it, I know it has not been easy. To Tiffany, thank you for being there when I needed guidance and support throughout the completion of two thesis projects. I likely would not be where I am, nor who I am today without you. Special thanks are also due to my family, both near and far away, for their unwavering support. Thanks to my mom, Sophia-Marie Carew, for giving me my first taste of university life as a wee baby, and for the years of love, pep talks, and hugs. To my grandparents, Don and Marie Carew, I could not have done this without you, your dedication to helping me along the way is without parallel. To Calvin and Chloe Carew, thanks for the laughs, for the long nights of de-stress karaoke, Los Angeles, and everything in-between. iii Dedication To my future self, I hope this was worth it. “You can do what makes you happy, just get the paper first.” – T.B. iv Table of Contents Abstract .......................................................................................................................................... ii Acknowledgements ...................................................................................................................... iii Dedication ..................................................................................................................................... iv Table of Contents .......................................................................................................................... v List of Figures .............................................................................................................................. vii List of Tables ................................................................................................................................ ix List of Abbreviations ................................................................................................................... xi Chapter 1: Introduction ............................................................................................................... 1 Background ......................................................................................................................... 1 1.2 Literature Review................................................................................................................ 3 1.2.1 Description of Algonquin Park ................................................................................. 3 1.2.2 Algonquin Park lake management ............................................................................ 4 1.2.3 Paleolimnology ......................................................................................................... 5 1.2.4 Chironomids and chaoborids as paleoindicators ....................................................... 6 References ........................................................................................................................... 9 Figures and Tables ............................................................................................................ 13 Chapter 2: Limnological and biotic relationships with volume-weighted hypolimnetic oxygen (VWHO) in Algonquin Park lakes and the development of a new dipteran-VWHO inference model ........................................................................................................................... 16 2.1 Introduction ....................................................................................................................... 16 2.2 Methods............................................................................................................................. 18 2.2.1 Data collection, field sampling, and laboratory methods ....................................... 18 2.2.2 Numerical analyses ................................................................................................. 20 2.3 Results ............................................................................................................................... 22 2.4 Discussion ......................................................................................................................... 25 2.5 References ......................................................................................................................... 33 2.6 Figures and Tables ............................................................................................................ 37 Chapter 3: A top-bottom paleolimnological approach for assessing change in volume- weighted hypolimnetic oxygen (VWHO) in Algonquin Park lakes ........................................ 58 3.1 Introduction ....................................................................................................................... 58 3.2 Methods............................................................................................................................. 60 v 3.2.1 Field sampling and laboratory methods .................................................................. 60 3.2.2 Statistical methods .................................................................................................. 61 3.2.3 An introduction to causal inference ........................................................................ 63 3.2.4 Development of a causal diagram and computing validation adjustment sets ....... 65 3.3 Results ............................................................................................................................... 68 3.4 Discussion ......................................................................................................................... 70 3.5 References ......................................................................................................................... 75 3.6 Figures and Tables ............................................................................................................ 80 4.0 Conclusion ....................................................................................................................... 87 Appendices ................................................................................................................................... 89 vi List of Figures Figure 1.1 Map of Algonquin Park boundary, Ontario. Map generated with ESRI imagery…………………………………………………………………………………………..13 Figure 1.2 Photos of Algonquin Park showing