Influence of Habitat Disturbances on Endemic Grassland Bird Distributions in Loamy Ecological Range Sites at Canadian Forces Base Suffield, Alberta
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University of Calgary PRISM: University of Calgary's Digital Repository Graduate Studies The Vault: Electronic Theses and Dissertations 2015-06-18 Influence of Habitat Disturbances on Endemic Grassland Bird Distributions in Loamy Ecological Range Sites at Canadian Forces Base Suffield, Alberta McWilliams, Benjamin McWilliams, B. (2015). Influence of Habitat Disturbances on Endemic Grassland Bird Distributions in Loamy Ecological Range Sites at Canadian Forces Base Suffield, Alberta (Unpublished master's thesis). University of Calgary, Calgary, AB. doi:10.11575/PRISM/26516 http://hdl.handle.net/11023/2306 master thesis University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission. Downloaded from PRISM: https://prism.ucalgary.ca UNIVERSITY OF CALGARY Influence of Habitat Disturbances on Endemic Grassland Bird Distributions in Loamy Ecological Range Sites at Canadian Forces Base Suffield, Alberta by Benjamin Earl McWilliams A THESIS SUBMITTED TO THE FACULTY OF GRADUATE STUDIES IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE GRADUATE PROGRAM IN GEOGRAPHY CALGARY, ALBERTA JUNE, 2015 © Benjamin Earl McWilliams 2015 ABSTRACT Many grassland birds are at risk and habitat disturbance may have an important influence on the persistence of these species. Military bases provide an opportunity to examine the influence of habitat disturbance on grassland birds, whose distributions are influenced by vegetation structure. Spatial autocovariate generalized linear models were developed for four primary endemic grassland bird species from point count data collected in loamy ecological range sites during spring 2013 and 2014. These models indicated habitat disturbances influenced bird distribution, but the response differed among species. The strongest response was to fire; relative abundance of two species increased with greater fire impact while the other two decreased. A Wilcoxon Signed- Rank test of matched burned and unburned areas showed fire reduced remotely sensed grassland vegetation (p < 0.001). These results indicate disturbed and undisturbed areas provide a range of habitats suitable to the endemic grassland bird species studied. ii ACKNOWLEDGEMENTS I would like to first thank my supervisor, Dr. Darren Bender, for guidance, fruitful discussions, and the time and effort he put into facilitating the successful conclusion of this study. Also, the members of my thesis examination committee, Dr. Stephania Bertazzon, Dr. Greg McDermid, and Dr. Paul Galpern, for feedback that improved the final product of this thesis. I specifically thank Stefania Bertazzon for assistance in application of spatial statistical methods. Many CFB Suffield staff provided assistance throughout this study. Drew Taylor joined me in early morning point counts. Brent Smith taught me a much more detailed appreciation of grassland vegetation dynamics than I would have acquired otherwise. Marty Gartry provided access and context to several of the databases, as well as hundreds of hours in their development. Performing bird surveys in the busy landscape of CFB Suffield would not have been possible without support and coordination provided by Mike Locke, Brian Talty, John Deruyter and many at Range Control. Many others in the Range Sustainability Section also indirectly contributed to my research, often through informal discussions of land use activities occurring at CFB Suffield. Prior to the inception of this thesis, Brenda Dale provided invaluable training in conducting point counts, as well as encouragement to pursue grassland bird research. Finally, I thank my wife and children for tolerating the time I needed to dedicate to this study and for frequently helping me take my mind off school. iii DISCLAIMER Opinions expressed or implied in this publication are those of the author, and do not represent the views of the Department of National Defence, the Canadian Forces, or any agency of the Government of Canada. iv TABLE OF CONTENTS ABSTRACT ........................................................................................................................ ii ACKNOWLEDGEMENTS ............................................................................................... iii DISCLAIMER ................................................................................................................... iv TABLE OF CONTENTS .................................................................................................... v LIST OF TABLES ........................................................................................................... viii LIST OF FIGURES ............................................................................................................ x LIST OF SYMBOLS AND ABBREVIATIONS .............................................................. xi CHAPTER 1: INTRODUCTION ............................................................................ 1 1.1 Study Context .......................................................................................................... 1 1.2 Influence of Topography on Grassland Vegetation .................................................. 4 1.3 Grassland Disturbance Ecology ................................................................................ 5 1.3.1 Fire Ecology of Grassland Birds and Vegetation ............................................. 5 1.3.2 Off-road Vehicle Disturbance .......................................................................... 8 1.3.3 Road Disturbance ............................................................................................. 9 1.4 Remote Sensing Vegetation Indices ....................................................................... 10 1.5 Research Objectives ................................................................................................ 11 CHAPTER 2: METHODS .................................................................................... 14 2.1 Study Area .............................................................................................................. 14 2.2 Study Species .......................................................................................................... 17 2.2.1 McCown’s longspur ................................................................................. 18 2.2.2 Chestnut-collared longspur ...................................................................... 19 v 2.2.3 Sprague’s pipit ......................................................................................... 20 2.2.4 Baird’s sparrow ........................................................................................ 21 2.3 Identifying Bird Distribution .................................................................................. 23 2.4 Environmental Variables ........................................................................................ 28 2.4.1 Topographic Variables ................................................................................... 29 2.4.2 Disturbance Variables ..................................................................................... 30 2.5 Expectations of Bird Responses to Topographic and Disturbance Variables......... 37 2.6 Statistical Analysis .................................................................................................. 40 2.5.1 Spatial Exploratory Data Analysis ................................................................. 40 2.5.2 Multicollinearity Analysis .............................................................................. 40 2.5.3 Accounting for Spatial Autocorrelation ......................................................... 41 2.5.4 Disturbance Modelling Analysis .................................................................... 43 2.5.5 Bivariate Regression of Relative Abundance and Composite Fire Index ...... 46 2.5.6 Influence of Burn Status and Topographic Position on Vegetation ............... 46 CHAPTER 3: RESULTS ..................................................................................... 49 3.1 Spatial Exploratory Data Analysis .......................................................................... 49 3.2 Correlation Matrix .................................................................................................. 49 3.3 Disturbance Modelling Analysis............................................................................. 52 3.4 Bivariate Response of Endemic Bird Study Species to Fire ................................... 56 3.5 Influence of Burn Status and Topographic Position on Vegetation ....................... 58 CHAPTER 4: DISCUSSION ............................................................................... 61 4.1 Disturbance Modelling............................................................................................ 62 vi 4.1.1 Disturbance: Fire, Trafficking, Pipelines ....................................................... 62 4.1.2 Topography: Slope, Solar Radiation, Topographic Position .......................... 69 4.1.3 Limitation of the model results ....................................................................... 72 4.2 Model Evaluation .................................................................................................... 73 4.3 Influence