Ecological Scale and Species-Habitat Modeling: Studies on the Northern Flying Squirrel. 1 2 3 by 4 5 Matthew Thompson Wheatley 6 7 B.Sc., University of Alberta, 1994 8 M.Sc., University of Alberta, 1998 9 10 11 A Dissertation Submitted in Partial Fulfillment of the 12 Requirements for the Degree of 13 14 DOCTOR OF PHILOSOPHY 15 16 In the Department of Biology 17 18 19 20 21 22 23 24 25 Matthew Thompson Wheatley, 2010 26 University of Victoria 27 28 All rights reserved. This thesis may not be reproduced in whole or in part, by photocopy 29 or other means, without the permission of the author. 30 ii Supervisory Committee 31 32 33 34 35 Ecological Scale and Species-Habitat Modeling: Studies on the Northern Flying Squirrel. 36 37 38 by 39 40 Matthew Thompson Wheatley 41 42 B.Sc., University of Alberta, 1994 43 M.Sc., University of Alberta, 1998 44 45 46 47 48 49 50 51 52 53 Supervisory Committee 54 55 Dr. Karl Larsen, Department of Biology 56 Co-Supervisor 57 58 Dr. Pat Gregory, Department of Biology 59 Co-Supervisor 60 61 Dr. John Taylor, Department of Biology 62 Departmental Member 63 64 Dr. Dave Duffus, Department of Geography 65 Outside Member 66 67 Dr. Richard Bonar, Hinton Wood Products (West Fraser Mills Ltd.) 68 Additional Member 69 70 iii Abstract 71 72 Supervisory Committee 73 Dr. Karl Larsen, Department of Biology 74 Co-Supervisor 75 Dr. Pat Gregory, Department of Biology 76 Co-Supervisor 77 Dr. John Taylor, Department of Biology 78 Departmental Member 79 Dr. Dave Duffus, Department of Geography 80 Outside Member 81 Dr. Richard Bonar, Hinton Wood Products (West Fraser Mills Ltd.) 82 Additional Member 83 84 85 86 Although scale is consistently identified as the central problem in ecology, empirical 87 examinations of its importance in ecological research are rare and fundamental concepts 88 remain either largely misunderstood or incorrectly applied. Due to the mobile and wide- 89 ranging nature of wildlife populations, species-habitat modeling is a field in which much 90 proliferation of multi-scale studies has occurred, and thus provides a good arena within 91 which to test both scale theory and its application. Insufficient examination of a relevant 92 breadth of the scale continuum could be an important constraint in all multi-scale 93 investigations, limiting our understanding of scalar concepts overall. Here I examine 94 several concepts of ecological scale by studying free-ranging populations of northern 95 flying squirrels (Glaucomys sabrinus), purported to be a keystone species in northern 96 forests. Coarse-grain digital forest coverage revealed that flying squirrels in the boreal 97 and foothills of Alberta were not conifer specialists, rather forest generalists regarding 98 stand type and age. Lack of coarse-grain scale effects led me to examine fine-grain data, 99 including an assessment of scale domains using a novel continuum approach. Fine-grain 100 data revealed important scale-related biases of trapping versus telemetry, namely that, at 101 fine-grain scales, different habitat associations could be generated from the same data set 102 based on methods alone. Then, focusing on spatial extent, I develop a true multi-scalar 103 approach examining scale domains. First, I quantify only forest attributes across multiple 104 extents, and demonstrate unpredictable scale effects on independent variables often used 105 in species-habitat models. Second, including both independent (habitat) and dependent 106 iv (squirrel telemetry) variables in the same approach, I demonstrate that the relative 107 ranking and strength-of-evidence among different species-habitat models change based 108 on scale, and this effect is different between genders and among life-history stage (i.e., 109 males, females, and dispersing juveniles). I term this the “continuum approach”, the 110 results of which question the validity of many published species-habitat models. Lastly, I 111 attempt to clarify why existing models should be scrutinized by reviewing common 112 rationales used in scale choice (almost always arbitrary), outlining differences between 113 “observational scale” and the commonly cited “orders of resource selection”, and making 114 a clear distinction between multi-scale versus multi-design ecological studies. 115 116 v Table of Contents 117 118 Supervisory Committee ...................................................................................................... ii 119 Abstract .............................................................................................................................. iii 120 Table of Contents ................................................................................................................ v 121 List of Tables .................................................................................................................... vii 122 List of Figures .................................................................................................................... ix 123 Acknowledgments.............................................................................................................. xi 124 Dedication ........................................................................................................................ xiii 125 126 Chapter 1. Ecology of northern flying squirrels, a scalar approach. ........................... 1 127 The Intellectual Journey .................................................................................................. 1 128 Introduction ..................................................................................................................... 2 129 Why Scale? ................................................................................................................. 3 130 Implications of ecological grain and extent ................................................................ 5 131 The Northern Flying Squirrel...................................................................................... 8 132 133 Chapter 2. Using GIS to relate small mammal abundance and landscape structure 134 at multiple spatial extents: Northern flying squirrels in Alberta, Canada. ............... 11 135 Abstract ......................................................................................................................... 11 136 Introduction ................................................................................................................... 12 137 Materials and Methods .................................................................................................. 15 138 Study Location .......................................................................................................... 15 139 Site selection. ............................................................................................................ 18 140 Sampling techniques ................................................................................................. 18 141 Landscape composition ............................................................................................. 19 142 Statistical analysis ..................................................................................................... 20 143 Results ........................................................................................................................... 22 144 Discussion ..................................................................................................................... 29 145 146 Chapter 3. Differential space use inferred from live-trapping versus telemetry: 147 Northern flying squirrels and fine spatial grain. ......................................................... 32 148 Abstract ......................................................................................................................... 32 149 Introduction ................................................................................................................... 32 150 Study Area .................................................................................................................... 36 151 Materials and Methods .................................................................................................. 37 152 Live-trapping and radio collaring ............................................................................. 37 153 Radio tracking ........................................................................................................... 38 154 Determination of space use ....................................................................................... 39 155 Vegetation Sampling ................................................................................................. 40 156 Statistical Analyses ................................................................................................... 41 157 Results ........................................................................................................................... 42 158 Spatial relationships: forage, nest, and capture sites ................................................. 42 159 Spatially-explicit time budgets ................................................................................. 42 160 vi Vegetation structure comparisons ............................................................................. 43 161 Discussion ..................................................................................................................... 47 162 163 Chapter 4. Domains of scale in forest landscape metrics: Implications