Interactions between mussel bed area and perimeter predict the response of associated communities and ecosystem functions Laurence Paquette Department of Biology McGill University Montréal, Québec, Canada April 2015 A thesis submitted to McGill University in partial fulfillment of the requirements of the degree of Master of Science © Laurence Paquette, 2015 Preface Acknowledgements First, I sincerely thank Frédéric Guichard for his supervision, funding support and advices which allowed me to bring this project to completion. I also greatly thank Philippe Archambault for his support and his contagious enthusiasm which revived my pleasure in accomplishing this project, in the harder moments. Thanks to Anthoni Ricciardi, member of my supervisory committee, for his suggestions. I would especially like to thank Myriam Lemelin for her very helpful field assistance. She was not only essential to the realization of this project, but it was also a pleasure to share a summer with her. I thank Julie Joseph, Nicolas LeCorre, Julie-Anne Dorval, Brian Boivin and Olivier Cloutier for field assistance. I am grateful to Lisa Treau De Coelli, Laure de Montety, Julien Massé Jodoin and César Largaespada for their contribution in the laboratory work. Thank to Gwenaёlle Chaillou and Steeven Ouellet for technical support in laboratory and to Alain Caron and Guillaume Larocque for statistical advising. I wish to express my gratitude to the members (the list is too long) of the Guichard lab and the Benthic Ecology lab. Thank you for your advices, listening and support. It was nice to be in your company. Finally, I want to express my deep gratitude to my partner in life and my family who always believed in me and supported me, even from a distance. This work was supported by grants from the Natural Sciences and Engineering Research Council of Canada and the Fonds de recherche du Québec -Nature et technologies. Contribution of authors Laurence Paquette developed, planned, managed and participated to the collection and analyses of all data. Statistical analyses and writing of this thesis were also realized by Laurence Paquette. Frédéric Guichard and Philippe Archambault contributed by their suggestions and comments throughout the process and the writing. ii Table of contents Preface ...................................................................................................................... ii Acknowledgements .................................................................................................. ii Contribution of authors ............................................................................................. ii Table of contents..................................................................................................... iii List of tables ............................................................................................................. v List of figures ........................................................................................................... v Abstract .................................................................................................................... vi Résumé ................................................................................................................... vii Chapter 1: General Introduction ............................................................................. 2 Introduction ............................................................................................................. 2 Area effect............................................................................................................... 3 Shape parameters are interrelated ......................................................................... 3 Perimeter effect ....................................................................................................... 5 Effect of the interaction between perimeter and area .............................................. 6 Mussel bed ecosystem in the St Lawrence estuary ................................................ 7 Functional groups ................................................................................................... 9 Ecosystem processes ........................................................................................... 10 Objective ............................................................................................................... 11 Chapter 2 ................................................................................................................. 12 From habitat geometry to ecosystem functions in marine mussel beds .......... 12 Introduction ........................................................................................................... 13 Method .................................................................................................................. 16 Data collection ............................................................................................................. 16 Study site ................................................................................................................. 16 Mussel transplants ................................................................................................... 17 Community of associated taxa .................................................................................. 18 Ecosystem functions................................................................................................. 19 Data analysis ............................................................................................................... 20 Community of associated taxa .................................................................................. 20 Ecosystem functions................................................................................................. 22 Results .................................................................................................................. 23 iii Community of associated taxa ..................................................................................... 23 Community with Littorina sp. ..................................................................................... 23 Community without Littorina sp. ................................................................................ 23 Functional groups ..................................................................................................... 24 Ecosystem functions .................................................................................................... 24 Discussion............................................................................................................. 25 Community of associated taxa ..................................................................................... 26 The spatial scale .......................................................................................................... 26 Ecosystem functions .................................................................................................... 27 The effects of habitat area and perimeter on mussel bed ecosystem ........................... 28 Area effect on community characteristics ................................................................. 28 Effect of the interaction between area and perimeter on the community and on other ecosystem properties ............................................................................................... 29 Conclusion ............................................................................................................ 31 Tables ...................................................................................................................... 32 Figures .................................................................................................................... 37 Chapter 3: General conclusion ............................................................................. 43 Summary and future perspectives ........................................................................ 43 Shape effect in marine systems ................................................................................... 43 Community composition ............................................................................................... 44 Interrelated shape effects and their mechanisms ......................................................... 45 Spatial scale ................................................................................................................ 46 Development of tools for seascape studies .................................................................. 47 Implications ........................................................................................................... 47 References .............................................................................................................. 49 Appendix 1 .............................................................................................................. 63 Appendix 2 .............................................................................................................. 64 Appendix 3 .............................................................................................................. 65 Appendix 4 .............................................................................................................. 66 iv List of tables Table 1. Linear mixed effects models showing the effect of A) area, perimeter and of B) P/A ratio on taxonomic characteristics of the