1.4. Northern Temperate and Boreal Forests in Ontario 11 1.4.1
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Effects of Intensification of Silviculture on Plant Diversity in Northern Temperate and Boreal Forests of Ontario, Canada by Frederick Wayne Bell A Thesis presented to The University of Guelph In partial fulfilment of requirements for the degree of Doctor of Philosophy in Environmental Science Guelph, Ontario, Canada © F. Wayne Bell, January, 2015 ABSTRACT EFFECTS OF INTENSIFICATION OF SILVICULTURE ON PLANT DIVERSITY IN NORTHERN TEMPERATE AND BOREAL FORESTS OF ONTARIO, CANADA Frederick Wayne Bell Advisors: University of Guelph, 2015 Professor S. Hunt Professor S. G. Newmaster Professor M. Anand Dr. I. Aubin Dr. J. A. Baker This thesis is an investigation of the intensification of silviculture has long presented a conundrum to forest managers in the northern temperate and boreal forests of Ontario, Canada aiming to sustainably produce wood fibre and conserve biodiversity. Although intensive silviculture has long been viewed as a threat to biodiversity, it is also considered as a means to increase wood fibre production. In this thesis I determine the nature of the biodiversity– silviculture intensity relationships and improve our understanding of the mechanisms that underpin these relationships. More specifically, studied (i) compositional and functional biodiversity-silviculture intensity relationships, (ii) the relative influence of silviculture on species richness, (iii) effects of intensification of silviculture on functional response groups, and (iv) susceptibility to invasion. My results are based on fifth-year post-harvest NEBIE plot network data. Initiated in 2001, the NEBIE plot network is the only study in North America that provides a gradient of silviculture intensities in northern temperate and boreal forests. The NEBIE plot network is ii located in northern temperate and boreal forests near North Bay, Petawawa, Dryden, Timmins, Kapuskasing, and Sioux Lookout, Ontario, Canada. Data collections included plant diversity, soils, forest canopy structure, and forest floor structure. Response surface analyses, multiple regression, structural equation modelling, ordination, and fourth-corner analyses were used to analyze the data. Multiple response patterns, rather than a single pattern such as predicted by monoculture, intermediate disturbance or gradually reducing hypotheses, were observed. The effects of silviculture were marginal relative to climate, soils and biotic interactions. While the effects of silviculture systems were hierarchically associated with climate, soils, and historic fire regimes, the effects of silviculture intensity were independent of these factors. Fifty-six plant functional response groups (PFRGS) were formed based on specie’s individual persistence, competitive ability, propagule persistence, and landscape dispersal. These PFRGs were classified into 20 unique response patterns based on expected levels of abundance across the NEBIE gradient. The PFRGs associated with sensitive and recalcitrant species were observed in upwards of seven unique response patterns. The highest richness of exotic species was associated with basic silviculture. The propagule pressure and abiotic and biotic tolerance hypothesis provides a reasonable explanation for invasibility of northern forests. Keywords: biodiversity conservation, biological invasions, sustainable forest management, management intensity, forest ecology iii Dedication I dedicate this thesis to my parents for convincing me to give up a career in agriculture to pursue forestry and to Robert J. Day for introducing me to the concepts of silviculture and plant autecology during my formative years. Acknowledgements I am particularly indebted to my major advisors Drs. Shelley Hunt (University of Guelph) and Steven Newmaster (University of Guelph). In the midst of all of Shelley’s other obligations, she always found time to meet with me and spent time reviewing draft proposals and chapters. Steve’s enthusiasm, encouragement, and optimism helped me develop the confidence to pursue broad and interesting questions. Steve also granted me the permission to use his herbaceous species data sets (Chapters 3 to 7) and bryophyte and lichen data set (Chapter 3). I thank my committee members, Drs. James Baker (Ontario Ministry of Natural Resources), Madhur Anand (University of Guelph) and Isabelle Aubin (Natural Resources Canada – Canadian Forest Service) for valuable input during the initial and final stages of the thesis. With Dr. Jim Baker I had thoughtful discussions about the scientific method. Following these discussions I reviewed the rules, laws, hypotheses, and theories of ecology—an exercise that I believe has provided me a broad understanding of ecological theory. Dr. Madhur Anand challenged many of my original ideas in a committee meeting in February 2009 and encouraged me to consider the use of the plant functional response trait approach and in another meeting in December 2010 to figure out a means to address issues related to collinearity and hierarchy in the iv species richness–environment relationships (Chapter 4). Dr. Isabelle Aubin’s Traits of Plants in Canada (TOPIC) database (Chapters 3, 5, 6, and 7) and R software script enabled the research on functional diversity (Chapter 3), and plant functional response groups (Chapters 5 and 6) and invasibility (Chapter 7). In addition to my committee I owe gratitude to Jennifer Dacosta (Ontario Forest Research Institute) for assistance with managing the NEBIE databases, advancing the TOPIC database, and the use of R-software; Drs. Mahadev Sharma (Ontario Forest Research Institute) for use of SAS software and advice on multiple regression analysis; Dr. Eric Lamb (University of Saskatchewan) for training on MPlus software and advice on structural equation modeling; Dr. Mark Leithead for advice on path analysis, Dr. Pedro Antunes (Algoma University) for encouraging me to consider a chapter on invasibility and for reviewing and commenting on the final version and Dr. Guy Larocque (NRCan- CFS) for reviewing and commenting on earlier drafts of Chapter 3). Many long hard hours went into the data collection for this project. I extend a special thanks to John Winters, Amy Bolduc, Ray Ferguson, Neil Wester, Jose Maloles, Heather Cole, and Andrea Reid for field data collections; and to Monique Wester, Peter Uhlig, and Rachelle Lalonde for soils training. I express gratitude to the Ontario Ministry of Natural Resources (OMNR) for granting me the time to undertake this educational opportunity. I thank David DeYoe for suggesting that I complete a PhD and Fraser Dunn, Paul Ward, Frank Kennedy, and Dan Puddister for working through the approval process. v I thank the Ontario Ministry of Natural Resources (OMNR), Upper Lakes Environmental Research Network, University of Guelph, Canadian Ecology Centre–Forestry Research Partnership, and Forest Ecosystem Science Co-op for supporting and co-managing the NEBIE plot network and OMNR, Living Legacy Trust, Forestry Futures Trust, and Natural Science and Engineering Research Council of Canada for financial support. I gratefully acknowledge the role of Tembec Inc., Nipissing Forest Management, Domtar (formerly Weyerhaeuser), Buchanan Forest Products, Resolute Forest Products (formerly Abitibiti-Bowater),and the Canadian Forest Service in developing and implementing harvest and silviculture strategies. Finally, but not least, I owe a special thank you to my wife and co-worker Lisa Buse who endured the process and raised our two teenage boys while I completed the first three semesters preparing for my qualifying exams and reviewed earlier drafts of individual chapters. vi Table of Contents Dedication ....................................................................................................................................................... iv Acknowledgements ......................................................................................................................................... iv List of Tables ................................................................................................................................................... xv List of Figures ................................................................................................................................................. xix Chapter 1: Introduction .................................................................................................................................... 1 Abstract 1 1.1. Thesis goal 1 1.2. Background 2 1.3. Conserving forest biodiversity 7 1.3.1. International efforts to conserve biodiversity 7 1.3.2. Principles and strategies for conserving biodiversity in Ontario 8 1.3.3. Natural disturbance-based silviculture 10 1.4. Northern temperate and boreal forests in Ontario 11 1.4.1. General introduction 11 1.4.2. Northern temperate forests 12 1.4.3. Boreal forests 13 1.5. Rationale for interest in intensive silviculture in Ontario’s forests 15 1.5.1. Ontario’s forests 15 1.5.2. What lead to intensive silviculture research in Ontario? 15 1.5.2.1. Ontario Living Legacy and the Ontario Forest Accord.................................................. 16 1.5.2.2. 1999 Intensive Forest Management Science Workshop .............................................. 17 1.6. Definitions 18 1.6.1. Background 18 1.6.2. Biodiversity terms 20 1.6.3. Disturbance -related terms 22 1.6.4. General forestry terms 23 1.6.5. Silviculture terms 24 vii 1.7. Summary 27 1.8. References 28 Chapter 2: Overview of approach ..................................................................................................................