TITLE PAGE Transmission Lines as Tall-grass Prairie Habitats: Local Mowing, Spraying, and Surrounding Urbanization as Determinants of Wildlife Richness and Abundance by Lionel Leston A Thesis submitted to the Faculty of Graduate Studies of The University of Manitoba in partial fulfillment of the requirements of the degree of Doctor of Philosophy Clayton H. Riddell Faculty of Environment, Earth, and Resources Natural Resources Institute University of Manitoba Winnipeg Copyright © 2013 by Lionel Leston 1 THE UNIVERSITY OF MANITOBA FACULTY OF GRADUATE STUDIES ***** COPYRIGHT PERMISSION Transmission Lines as Tall-grass Prairie Habitats: Local Mowing, Spraying, and Surrounding Urbanization as Determinants of Wildlife Richness and Abundance by Lionel Leston A Thesis submitted to the Faculty of Graduate Studies of The University of Manitoba in partial fulfillment of the requirement of the degree Of Doctor of Philosophy In Natural Resources and Environmental Management (PhD) © 2013 by Lionel Leston 2 Permission has been granted to the Library of the University of Manitoba to lend or sell copies of this thesis, to the National Library of Canada to microfilm this thesis and to lend or sell copies of the film, and to University Microfilms Inc. to publish an abstract of this thesis/practicum. This reproduction or copy of this thesis has been made available by authority of the copyright owner solely for the purpose of private study and research, and may only be reproduced and copied as permitted by copyright laws or with express written authorization from the copyright owner. 3 Abstract To manage underused urban grassy spaces like transmission lines as tall-grass prairie habitats or other endangered ecosystems, ecologists need to know how mowing, spraying and surrounding urban lands affect species richness and numbers of plants and animals along transmission lines. I conducted surveys along 48 transmission lines in Winnipeg, Manitoba in 2007-2009 to answer these questions, and I concluded that mowing and spraying should be reduced, but not eliminated, to increase butterflies and other arthropods, resources for butterflies and other arthropods, and arthropod prey for birds. However, the amount of nearby urban land reduced plant species richness and grassland bird abundance along lines more strongly than mowing or spraying, suggesting that lines with less neaby urban land should be selected for management as grassland bird habitats. Mowing and spraying can then be reduced along these lines to benefit other species, enabling urban lands like transmission lines to contribute to conservation. 4 Acknowledgments This study was made possible by the Manitoba Hydro Research and Development Grant, Manitoba Conservation Sustainable Development Innovations Fund, Environment Canada’s Science Horizons Fund, Manitoba Career Focus Program, and the University of Manitoba’s Faculty of Graduate Studies. Academic advice for this study came primarily from Dr. Nicola Koper, and additionally from Dr. Micheline Manseau, Dr. Terry Galloway, and Dr. Douglas Johnson. Field work was conducted by Dong-jie Bao, Alley Krause-Danielsen, Praepun Khattiyakornjaroon, Kimberley Madsen, Chelsea May, Ellen Reid, and Jennifer Tran. In-kind support was provided by Dr. Robert Roughley and Technician Dave Holder (University of Manitoba, Department of Entomology), Tamara Keedwell and Dalia Naguib (University of Manitoba, Natural Resources Institute), and Wade Munro, Trent Hreno, Wayne Ortiz, and Spencer Heaman (Manitoba Hydro). Vegetation at my experimental sites was mowed by Manitoba Hydro personnel (Wayne Ortiz, Spencer Heaman) and Neil van Ryssel (agricultural producer, Oakbank, Manitoba). I also wish to thank Jim Rivers (Oregon State University) for advice on what bill dimensions to measure, Emily Pipher (University of Manitoba) for collecting bill dimensions from Savannah Sparrow nestlings in Grasslands National Park, and Dr. Randy Mooi, (Manitoba Museum of Man and Nature) for providing grassland bird specimens from which I obtained bill measurements for this study. 5 Dedication This thesis is dedicated to my father (Lionel Leonard Vernon Leston), mother (Christine Margaret Evans-Leston), stepmother (Nancy Leston), siblings (Carl, Elizabeth, Shane), and partner (David Diakowich). 6 Table of Contents TITLE PAGE ......................................................................................................................... 1 Abstract ............................................................................................................................... 4 Acknowledgments............................................................................................................... 5 Dedication ........................................................................................................................... 6 Table of Contents ................................................................................................................ 7 List of Figures .................................................................................................................. 23 List of Tables ................................................................................................................... 30 List of Appendices ........................................................................................................... 33 Chapter 1. Introduction ..................................................................................................... 35 Background ..................................................................................................................... 35 Effects of Mowing and Spraying on Plants and Animals Along Transmission Lines .......... 35 Effects of Surrounding Built-up Lands and Other Land Uses on Plants and Animals Along Transmission Lines ................................................................................................................ 37 Theoretical Frameworks and Definitions ..................................................................... 38 Purpose............................................................................................................................. 40 Objectives......................................................................................................................... 40 Methods ............................................................................................................................ 41 Power Analysis ...................................................................................................................... 41 Study Area and Study Sites ................................................................................................... 42 Measuring Surrounding Land Use Around Study Sites ........................................................ 42 Surveys .................................................................................................................................. 43 Analyses ................................................................................................................................ 44 Organization of Thesis .................................................................................................... 45 Literature Cited .............................................................................................................. 46 7 Table 1.1. Names of all 56 study sites, their Manitoba Hydro line designations, UTM locations (northing, easting) of the transect starting point at each site, and mowing regime (M.R.): unmowed = U; hayed once a year = H; 1x, 2x = mowed 1- 2 times a year. ........ 53 Table 1.2.Proportions of different land uses within 100 m of the 56 study sites. Italics = sites not used in analyses in Chapters 2-4. Remnant prairie sites in italics. Bold = control and treatment sites from the mowing experimental study (Chapter 4). ............................ 54 Chapter 2. Experimentally Disentangling the Effects of Urbanization from Mowing on Prairie Wildlife Along Urban Transmission Lines ........................................................... 55 Abstract ............................................................................................................................ 55 Introduction ..................................................................................................................... 56 Methods ............................................................................................................................ 59 Study Area ............................................................................................................................. 59 Land Cover Classes Around Sites .......................................................................................... 60 Long-Term Mowing Regime Along Transmission Lines ....................................................... 61 Short-term Mowing Experiment Along Transmission Lines .............................................. 62 Vegetation Surveys ............................................................................................................... 63 Butterfly Surveys ................................................................................................................... 64 Other Arthropod Surveys ...................................................................................................... 65 Bird Surveys ........................................................................................................................... 66 Analyses ...............................................................................................................................