IMPACTS AND MONITORING OF CLIMATE-DRIVEN CHANGES TO WETLAND HYDROPERIODS ON WOOD FROG POPULATIONS by Paul S. Crump B.Sc. University of Cardiff, 2005 A Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in the Graduate Academic Unit of Biology Supervisor: Jeff Houlahan, Ph. D., Dept. of Biology Examining Board: Kenneth Sollows, Ph. D., Dept. of Engineering (Chair) Heather Hunt, Ph. D., Dept. of Biology Donald McAlpine, Ph. D., New Brunswick Museum External Examiner: David Green, Ph. D., Redpath Museum, McGill University This dissertation is accepted by the Dean of Graduate Studies THE UNIVERSITY OF NEW BRUNSWICK September, 2017 ©Paul S. Crump, 2017 ABSTRACT Climate change has the potential to alter the strength of species interactions, but not only do we lack sufficient information about possible species responses, we also lack the tools to monitor and document these changes over meaningful spatial scales. Due to their physiology and life history, ectotherms such as amphibians, are particularly sensitive to changes in prevailing environmental conditions. Amphibians breed in a variety of standing water body types and one of the main structuring variables is the amount of time the water body holds water, the hydroperiod. The province of New Brunswick in Canada is expected to warm by ~4.5°C and see anywhere from a 5-50% increase in precipitation over the next 100 years and, as a result, it is anticipated that pond hydroperiods could change. I conducted translocation experiments with wood frogs (Lithobates sylvaticus) to determine the effect of different hydroperiods on embryo and larval survivorship. Permanent ponds that contained overwintered green frog larvae (Lithobates clamitans) had lower embryo and larval survival than both permanent ponds without green frog larvae and ephemeral ponds. To investigate the population-level impacts I conducted simulations using a population projection model of different climate change and hydroperiod scenarios. I found that wetter conditions (i.e., longer hydroperiods) had a negative effect while drier conditions (i.e., shorter hydroperiods) had a positive effect, at least initially, on wood frog populations. In order to facilitate monitoring improvements for these and other population-level impacts, I used automated recorders and automated sound recognition models. I found that choice of variable settings had a greater impact on recognizer performance than the amount and type of ii training data, but increases in the number of sites used did improve performance slightly, and that by optimizing variable settings on new data it was possible to create reliably transferable models that minimized false negative (Type II) errors but not false positive (Type I) errors. I then used these bioacoustic monitoring tools to predict abundance in wood frog populations based on vocalization activity. The best model predicted egg mass abundance with an average absolute error of 16 masses and a relative error of 59%. Overall, I have provided evidence of an additional mechanism by which climate change can alter amphibian communities, as well as developed and evaluated a methodology to detect those alterations. iii DEDICATION This work is dedicated to my wife, Rachel, for her relentless support and patience while I attended graduate school and to my dog, Jiggs, for his companionship and for giving me a reason to walk around outside at night during the winter full moon. We miss you little man. iv ACKNOWLEDGEMENTS First and foremost I would like to thank my supervisor, Dr. Jeff Houlahan, for a stimulating and challenging graduate school experience, and for shooting straight about everything with me from the start. Thanks to my co-supervisor, Dr. Dean Thompson, and my supervisory committee, Dr. John Terhune, Dr. Heather Major, and Dr. Karen Kidd, for their help, guidance, and feedback throughout this process. I would like to thank my fellow Houlahan lab graduate students and friends, Jason Daniels and Raja Wetuschat, for great conversations about ecology, science, and life in general. Thanks also go to Kaitlyn Assadpour, Jordan Bartlett, Adam Debly, Luke Duffley, Eleni Hines, Jeff Hines, Jake Lewis, Nick McCullum, Rachel Rommel-Crump, and Lucy Smith for help in the field and the lab. Special thanks for Jesse Beyea for help in the field for the first two seasons and for helping me get familiar with the field site. Thanks go to Dr.’s Chris Edge, LeeAnn Baker, and Joe Mudge for sharing data and experiences about working on CFB Gagetown, and to all the other folks involved with setting up the Long-term Experimental Wetlands Area (LEWA) in 2008. Finally, I’d like to thank my parents for being cool, supportive people, my wife for just being amazing and so tolerant of me during this process, and that guy who when I was 19 and cleaning the floor at Wickes, put his foot on my brush and asked me “what the (bleep) are you still doin’ working here?”. That was a good question sir. v Table of Contents ABSTRACT ........................................................................................................................ ii DEDICATION ................................................................................................................... iv ACKNOWLEDGEMENTS ................................................................................................ v Table of Contents ............................................................................................................... vi List of Tables ..................................................................................................................... xi List of Figures ................................................................................................................. xvii CHAPTER 1 ....................................................................................................................... 1 1.1 General Introduction ................................................................................................. 1 1.2 References ................................................................................................................. 6 CHAPTER 2 ..................................................................................................................... 11 2. Overwintered green frog larvae cause high embryo mortality in wood frogs .......... 11 2.1 Abstract ............................................................................................................... 12 2.2 Introduction ......................................................................................................... 13 2.3 Methods............................................................................................................... 17 2.4 Results ................................................................................................................. 23 2.5 Discussion ........................................................................................................... 26 2.6 Acknowledgements ............................................................................................. 32 2.7 References ........................................................................................................... 32 vi CHAPTER 3 ..................................................................................................................... 50 3. Wood frog larvae survivorship is reduced in the presence of green frog larvae ...... 50 3.1 Abstract ............................................................................................................... 51 3.2 Introduction ......................................................................................................... 52 3.3 Methods............................................................................................................... 56 3.4 Results ................................................................................................................. 64 3.5 Discussion ........................................................................................................... 68 3.6 Acknowledgements ............................................................................................. 77 3.7 References ........................................................................................................... 77 CHAPTER 4 ................................................................................................................... 107 4. Modelling the population-level effects of climate change to wood frog populations ..................................................................................................................................... 107 4.1 Abstract ............................................................................................................. 108 4.2 Introduction ....................................................................................................... 109 4.3 Methods............................................................................................................. 114 4.4 Results ............................................................................................................... 124 4.5 Discussion ......................................................................................................... 126 4.6 Acknowledgements ........................................................................................... 132 4.7 References ........................................................................................................