Relative Effects of Landscape Structure Variables, and Interactions with Life
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Relative effects of landscape structure variables, and interactions with life- history traits, on the abundance and distribution of wetland-dependent vertebrate species by Pauline Elaine Quesnelle A thesis submitted to the Faculty of Graduate and Postdoctoral Affairs in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Biology Carleton University Ottawa, Ontario © 2014, Pauline Elaine Quesnelle Abstract Wetland-dependent species are undergoing the largest wildlife population declines worldwide primarily due to habitat loss, but are a relatively understudied ecological group in landscape ecology. The overarching goal of my dissertation is to advance our understanding of the effects of landscape structure on wetland-dependent vertebrate populations and the life-history traits that determine these responses. In Chapter 2, I used meta-analysis to combine data on the relationship between species abundance and wetland habitat loss from empirical studies conducted worldwide to identify the traits that influence species response to habitat loss. I show that species with low reproductive rates are more sensitive to habitat loss at the population level, whereas species mobility has no apparent effect. In Chapter 3, I conducted extensive field surveys to determine the relative effects of landscape structure variables on the distribution of wetland birds and turtles. I show that birds are more strongly affected by habitat loss whereas turtles are more strongly affected by the surrounding landscape matrix, specifically forest cover. I also show that habitat fragmentation independent of habitat loss was not an important predictor for any species. In Chapter 4, I investigated whether a similar pattern is found in other studies and vertebrate taxa by building upon the meta- analysis in Chapter 2 and comparing wetland species responses to wetland loss and landscape matrix quality at the population level. I show that wetland loss is more important for mammals and birds whereas matrix quality, indexed as forest cover, is more important for amphibians. I also show that these results are not scale-dependent. The results of this thesis suggest that conservation priority should be placed on species ii with low reproductive rates and on actions that increase reproductive output rather than movement. My results also suggest that landscape-scale requirements vary among wetland-dependent taxa: mammals and birds are more limited by the amount of wetland habitat in a landscape, whereas amphibians and reptiles are more limited by the quality of the matrix surrounding wetlands, likely due to access to and/or availability of complementary habitats. Therefore, conservation policies that focus only on wetland protection will not conserve wetland biodiversity. iii Preface Co-authorship Statement This thesis is formatted using the integrated thesis format, and therefore each data chapter was written as an independent manuscript. Chapters 2 and 3 have been published in, and Chapter 4 has been submitted to, a peer-reviewed journal when this thesis was completed. The text of each published chapter was reproduced in whole, but supplementary figures were added. There is some repetition in the introductions, methods and discussions; however I have cross-referenced between chapters to reduce repetition as much as possible. I performed the majority of work described in this thesis as follows. I proposed and developed the research questions in cooperation with Lenore Fahrig and Kathryn Lindsay, and I was primarily responsible for the design of the studies used to address these questions. I carried out all field work for Chapter 3 and collected all data for Chapters 2 and 4. I analysed all of the data and wrote all first drafts of the data chapters. I have permission from each publisher to reproduce published manuscripts in my thesis. I have also received permission from my co-authors Lenore Fahrig and Kathryn Lindsay to use the work in this thesis. A specific chapter that has been published elsewhere is copyrighted material and must be cited using the journal citation information provided below. However, to reference my thesis as a whole or an unpublished chapter, I recommend using the following citation: iv Quesnelle, P.E. 2014. Relative effects of landscape structure variables, and interactions with life-history traits, on the abundance and distribution of wetland-dependent vertebrate species. Ph.D. Thesis, Carleton University, Ottawa, Ontario, Canada. Chapters – Manuscript status at time of thesis completion Chapter 2: Quesnelle P.E., Lindsay K.E., Fahrig L. 2014. Low reproductive rate predicts species sensitivity to habitat loss: a meta-analysis of wetland vertebrates. PLOS ONE 9(3): e90926. doi:10.1371/journal.pone.0090926 Chapter 3: Quesnelle P.E., Fahrig L, Lindsay K.E. 2013. Effects of habitat loss, habitat configuration and matrix composition on declining wetland species. Biological Conservation 160:200-208. Chapter 4: Quesnelle P.E., Lindsay K.E., Fahrig L. In review. Relative effects of landscape-scale wetland amount and landscape matrix quality on wetland vertebrates: a meta-analysis. Ecological Applications. v Acknowledgements This research would not have been possible without the support of many people. First and foremost, I have learned so much from my supervisors Kathryn Lindsay and Lenore Fahrig. I thank them for their insight, guidance and patience during the making of this thesis. I also thank my advisory committee members, Jeremy Kerr and Lutz Tischendorf, for their helpful advice and comments that improved the quality of this thesis. For Chapters 2 and 4, I am grateful to all the wetland researchers who took the time to respond to my email inquiries and provided further information and/or data to support my meta-analyses. For Chapter 3, I am indebted to my field assistants Brent Lewis, Mary Beth Lynch and Katie Wall for their hard work and being “on-call” every day during their summer. I am grateful to Thousand Islands National Park for logistical and financial support. I would like to thank the Park staff for their support, especially Josh Van Wieren, Greg Saunders, Harry Szeto, and Jeff Leggo. I was fortunate to have advice on species sampling methods from Benoît Jobin (Canadian Wildlife Service, Québec) from the Least Bittern Recovery Team, Shaun Thompson and Marie-Andree Carrière (Ministry of Natural Resources, Kemptville) from the Ontario Multi-Turtle Recovery Team, and Cat Millar (U of Ottawa). Lastly, I would like to thank the many volunteers who came out in the field, as well as many private landowners, Ontario Parks and Conservation Authorities who granted access to wetlands on their properties. I would like to thank all members of the Geomatics and Landscape Ecology Research Lab for their help and insights throughout my thesis, especially Sara Collins, vi Kevin Ethier, Sandra Martins de Freitas, Jude Girard, Heather Bird Jackson, Amanda Martin, Theresa Patenaude, Trina Rytwinski, and Paul Zorn. I am fortunate to have family and friends who provided endless encouragement and support throughout my thesis, especially Pawan, Alyssa and Drew, Paul and Kristen, my Mom, Grandmother and sister Sarah. And to my husband Josh, who supported me in the decision to start my Ph.D., and believed in me every step of the way with love, enthusiasm, humour, and lots of turtle watching and birding. Funding for this thesis came from the Natural Sciences and Engineering Research Council of Canada scholarship, Carleton University and Parks Canada (Thousand Islands National Park). Lastly, I dedicate my thesis to the memory of my father, Paul Justin Quesnelle. vii Table of Contents Abstract ............................................................................................................................... ii Preface................................................................................................................................ iv Acknowledgements ............................................................................................................ vi Table of Contents ............................................................................................................. viii List of Tables ...................................................................................................................... x List of Figures .................................................................................................................... xi List of Appendices ............................................................................................................ xv Chapter 1: General Introduction ......................................................................................... 1 Chapter 2: Low reproductive rate predicts species sensitivity to habitat loss: a meta- analysis of wetland vertebrates ......................................................................................... 10 Abstract ......................................................................................................................... 10 Introduction ................................................................................................................... 11 Methods ......................................................................................................................... 14 Results ........................................................................................................................... 26 Discussion ....................................................................................................................