FOREST FRAGMENTATION EFFECTS AND THE CAVITY NEST MATERIAL REQUIREMENTS OF NORTHERN FLYING SQUIRRELS AND RED SQUIRRELS IN A FRAGMENTED SECONDARY HARDWOOD FOREST REGION OF ONTARIO, CANADA by Jesse Eric-Henry Patterson A thesis submitted in conformity with the requirements for the degree of Master of Science in Forestry Faculty of Forestry University of Toronto © Copyright by Jesse Eric-Henry Patterson 2008 Library and Bibliotheque et 1*1 Archives Canada Archives Canada Published Heritage Direction du Branch Patrimoine de I'edition 395 Wellington Street 395, rue Wellington Ottawa ON K1A0N4 Ottawa ON K1A0N4 Canada Canada Your file Votre reference ISBN: 978-0-494-39741-1 Our file Notre reference ISBN: 978-0-494-39741-1 NOTICE: AVIS: The author has granted a non­ L'auteur a accorde une licence non exclusive exclusive license allowing Library permettant a la Bibliotheque et Archives and Archives Canada to reproduce, Canada de reproduire, publier, archiver, publish, archive, preserve, conserve, sauvegarder, conserver, transmettre au public communicate to the public by par telecommunication ou par Plntemet, prefer, telecommunication or on the Internet, distribuer et vendre des theses partout dans loan, distribute and sell theses le monde, a des fins commerciales ou autres, worldwide, for commercial or non­ sur support microforme, papier, electronique commercial purposes, in microform, et/ou autres formats. paper, electronic and/or any other formats. The author retains copyright L'auteur conserve la propriete du droit d'auteur ownership and moral rights in et des droits moraux qui protege cette these. this thesis. Neither the thesis Ni la these ni des extraits substantiels de nor substantial extracts from it celle-ci ne doivent etre imprimes ou autrement may be printed or otherwise reproduits sans son autorisation. reproduced without the author's permission. In compliance with the Canadian Conformement a la loi canadienne Privacy Act some supporting sur la protection de la vie privee, forms may have been removed quelques formulaires secondaires from this thesis. ont ete enleves de cette these. While these forms may be included Bien que ces formulaires in the document page count, aient inclus dans la pagination, their removal does not represent il n'y aura aucun contenu manquant. any loss of content from the thesis. Canada Patterson, Jesse Eric-Henry. 2008. Forest fragmentation effects and the cavity nest material requirements of northern flying squirrels and red squirrels in a fragmented secondary hardwood forest region of Ontario, Canada. Master of Science in Forestry, Faculty of Forestry, University of Toronto. ABSTRACT Agriculturally induced fragmentation of hardwood forests has been extensive in southern Ontario, with important implications for biodiversity, such as the outright loss of species, contraction in species distributions, and reduced genetic diversity. The purpose of this thesis was to investigate the patterns of fragment occupancy, from a metapopulation perspective, as a function of landscape-level features and to identify significant aspects of habitat use, including nest material requirements, for northern flying squirrels {Glaucomys sabrinus) and red squirrels (Tamiasciurus hudsonicus) in highly fragmented secondary hardwood forests. The occurrence of G. sabrinus was positively correlated with fragment area, while T. hudsonicus occurrence was positively correlated with the basal area of coniferous trees. Both species primarily used shredded eastern white cedar {Thuja occidentalis) bark as nesting material, possibly due to a behavioural adaptation to reduce ectoparasite loads in the nest environment. II ACKNOWLEDGMENTS First, and foremost, I would like to thank my supervisor, Jay Malcolm, for his consistent intellectual support, advice, guidance, encouragement, enthusiasm, and master computer programming! My supervisory committee is gratefully acknowledged for their input and interest: Jeff Bowman, Danijela Puric-Mladenovic, and Sandy Smith. Their perspectives and insights significantly improved this thesis. I would like to thank the Grey Sauble Conservation Authority (GSCA), the Saugeen Valley Conservation Authority (SVCA) and the various private landowners who graciously made their land available for this study. I am also indebted to the GCSA, SVCA, and Ontario Ministry of Natural Resources (OMNR) for providing necessary landscape imagery, in particular Chris Hachey (GSCA), Jim Penner (SVCA), and Danijela Puric-Mladenovic (OMNR). Thistlewood Timber Frame Homes in Markdale, Ontario generously donated the lumber used for constructing the nest boxes, and for that I am grateful. The Patterson and Sharkey families are both owed a great debt of gratitude for graciously providing in-kind accommodation throughout the course of this study. Without the help of my field assistants this project would have never come to fruition. I would like to acknowledge Carly Armstrong, Stephen Patterson, Marianne Patterson, and Hillary Maddin for their field, logistic, and technical support during data collection. I also thank the Wildlife Ecology lab and my family and friends for two-years of discussion, support, and friendship. Funding for this project was provided by a Natural Sciences and Engineering Research Council (NSERC) Canada Graduate Scholarship to JEHP, an NSERC Undergraduate Summer Research Award to JEHP, and an NSERC research grant to J. Malcolm. iii TABLE OF CONTENTS ABSTRACT ii ACKNOWLEDGMENTS iii TABLE OF CONTENTS iv LISTOFTABLES vi LIST OF FIGURES vii GENERAL INTRODUCTION 1 STUDY AREA DESCRIPTION 5 CHAPTER 1: RELATIVE INFLUENCE OF LANDSCAPE STRUCTURE AND FRAGMENT AREA ON PATTERNS OF NORTHERN FLYING SQUIRREL AND RED SQUIRREL OCCURRENCE IN A SECONDARY HARDWOOD FOREST ABSTRACT 7 1. INTRODUCTION 8 2. METHODS 15 2.1 Site Selection 15 2.2 Sciurid Trapping 16 2.3 Habitat Measurements 18 2.4 Landscape Measurements 19 2.4.1 Mean Proximity Index 21 2.4.2 Mean Nearest Neighbour Distance 22 2.4.3 Proportion of Forest 23 2.4.4 Number of Patches 23 2.5 Statistical Analysis 23 2.5.1 Landscape Scale 23 2.5.2 Bivariate and multivariate approaches 25 3. RESULTS 27 3.1 Sciurid Abundance and Occurrence 28 iv 3.2 Spatial Independence 28 3.3 Landscape Scale 28 3.4 Logistic Regression 31 3.5 Redundancy Analysis 40 4. DISCUSSION 43 4.1 Scale of best model fit 43 4.2 Responses of Glaucomys sabrinus to habitat features 46 4.3 Responses of Glaucomys sabrinus to landscape structure features 50 4.4 Responses of Tamiasciurus hudsonicus to habitat features 54 4.5 Responses of Glaucomys sabrinus to landscape structure features 55 4.6 Misclassifying absence 57 4.7 Future directions and conclusions 58 CHAPTER 2: CAVITY NEST MATERIAL USE BY NORTHERN FLYING SQUIRRELS AND RED SQUIRRELS IN SOUTHERN ONTARIO: A CASE FOR THE NEST-PROTECTION HYPOTHESIS ABSTRACT 61 1. INTRODUCTION 62 2. METHODS 64 3. RESULTS 66 3.1 Nest Box Occupation 66 3.2 Nest Materials of Glaucomys sabrinus and Tamiasciurus hudsonicus 67 3.3 Nest Depth 69 4. DISCUSSION 71 GENERAL CONCLUSIONS 76 LITERATURE CITED 80 v LIST OF TABLES Table 1.1: Landscape and habitat variables for Glaucomys sabrinus in a fragmented secondary hardwood Great Lakes-St. Lawrence forest region. Slope, Pr(>lzl) and corrected Akaike Information Criterion (AICc) values are from logistic regression analysis for each individual predictor variable. Scales of best model fit and transformations are given in brackets beside corresponding terms. Bold indicates significant values (p < 0.05). Mean values (± 1 SD) are given separately for sites where Glaucomys sabrinus was present and absent 32 Table 1.2: As Table 1.1 except that data are for Tamiasciurus hudsonicus 33 Table 1.3: Effect of the most significant habitat variables on predicting Glaucomys sabrinus occurrence in secondary hardwood Great Lakes-St. Lawrence forests with the inclusion of the most significant landscape variables forced into a multiple logistic regression model. Significance level for entry into the model was a = 0.1; for exit it was 0.15. Characteristic scales of response and transformations are given in brackets beside corresponding terms 35 Table 1.4: As Table 1.3 except that data are for Tamiasciurus hudsonicus 36 Table 1.5: Results of redundancy analyses evaluating the significance of each landscape variable on predicting Glaucomys sabrinus occurrence without and with patch area partialled out (i.e., area entered as a covariate). Monte Carlo statistical tests were run with 9999 unrestricted permutations and species scores were centred and standardised 44 vi LIST OF FIGURES Figure 1.1: Map of Grey and Bruce counties, Ontario with sites where presence/absence of Glaucomys sabrinus and Tamiasciurus hudsonicus marked (stars). Two Universal Transverse Mercator, Zone 17 grid lines also are shown (map datum: NAD83) 17 Figure 1.2: Corrected Akaike Information Criterion (AICc) values from logistic regressions between Glaucomys sabrinus occurrence and mean proximity index, mean nearest neighbour distance, proportion of forest, and number of patches as a function of landscape radius for spatially independent (18 sites, lower line plot) and non-spatially independent (24 sites, upper line plot) data sets. The radius of best model fit is indicated (drop-down arrow) and Spearman correlation results (p and rs values) between the spatially independent and non-spatially independent AICc values are given 29 Figure 1.3: As Figure 1.2, except that values are for Tamiasciurus hudsonicus 30 Figure 1.4: Presence/absence of Glaucomys sabrinus in relation to the logio-transformed