Eastern Illinois University The Keep Masters Theses Student Theses & Publications 2014 Aspects of the Trophic Ecology of an Invertivorous Snake Community Meagan Amanda Thomas Eastern Illinois University This research is a product of the graduate program in Biological Sciences at Eastern Illinois University. Find out more about the program. Recommended Citation Thomas, Meagan Amanda, "Aspects of the Trophic Ecology of an Invertivorous Snake Community" (2014). Masters Theses. 1358. https://thekeep.eiu.edu/theses/1358 This is brought to you for free and open access by the Student Theses & Publications at The Keep. It has been accepted for inclusion in Masters Theses by an authorized administrator of The Keep. For more information, please contact [email protected]. The Graduate School~ ~ ILUNOIS UNIVERSITY. 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I have conferred with my graduate faculty advisor. My signature below indicates that I have read and agree with the above statements, and hereby give my permission to allow Booth Library to reproduce and dis ibute m thesis. M adviser's si nature indicates c · · the thesis. Tho('llQ.S PrintedName Please submit in duplicate. ASPECTS OF THE TROPHIC ECOLOGY OF AN INVERTNOROUS SNAKE COMMUNITY BY Meagan Amanda Thomas THESIS Submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE in BIOLOGICAL SCIENCES In the Graduate School, Eastern Illinois University Charleston, Illinois 2014 We hereby recommend that this thesis be accepted as fulfilling this part of the graduate degree cited above Date Date Date 2014 Copyright by Meagan A. Thomas ABSTRACT Understanding the significance of trophic links has been of interest to ecologists for decades, likely because food web studies have the potential to reveal a considerable amount of information in the fields of ecosystem and community ecology. Despite the intrinsic benefits that come from elucidating food web structures, doing so is often problematic because of the complex and dynamic nature of ecological communities. The dietary ecology of small-bodied invertivorous snakes remains relatively understudied compared to other snake species. Many of these species are abundant throughout their range, making them ideal organisms for studying community-level questions. I employed a combination of stable isotope analyses as well as gut and fecal material analyses to quantify the trophic niche width of five species of invertivorous snakes (genera: Coluber, Diadophis, Opheodrys, and Storeria) occurring in central Illinois. I investigated seasonal differences in capture rates and quantified morphometric and isotopic differences among species. I used Bayesian mixing models to determine the potential sources ofC13 and N 15 in scale, red blood cell, and plasmatissue samples. The stable isotope data, supported by the gut and fecal analyses, revealed differences in the levels of dietary specialization within the community. High levels of trophic niche overlap were detected, however, indicating that snake dietary preferences are more likely a product of taxonomic affinity and species specific life-history, rather than interspecific competition. Further studies that involve a combination of techniques can provide a more comprehensive understanding of dietary ecology within snake communities. DEDICATION This thesis is dedicated to my amazing mother, Amanda Mary Schenning-for all those hours she spent at the kitchen table helping me with my chemistry homework. I would not be half the person I am today without her guidance and unwavering support. ii ACKNOWLEDGMENTS The completion of this thesis is, by no means, the result of my work alone. Throughout the course of my time at Eastern Illinois University I have been lucky enough to be constantly surrounded with a fervent network of support. First and foremost, I would like to thank my committee members, Drs. Scott Meiners and Ann Fritz, as well as my advisor Dr. Stephen Mullin. I'm grateful to Dr. Meiners for awarding me unwavering patience, guidance, and time- which he always seemed to make for me, despite his busy schedule. I'm also grateful to Dr. Ann Fritz, her knowledge of insect communities is _extensive, and I greatly respect her work in behavioral ecology. In addition, this thesis would not be of the caliber it is without the help of my advisor Dr. Stephen Mullin. I have undoubtedly grown as a writer thanks to his unfaltering editorial eye, and as a researcher because of his constant encouragement to think outside my comfort zone. In addition to my committee members, I owe Dr. Richard Seigel an enormous amount of thanks for identifying a passion for research within me throughout my undergraduate career, and fostering my development as a scientist even to this day. I whole-heartedly thank all the individuals who helped with field and lab work throughout this project- Elizabeth Bauman, Sarah Baxter, Cynthia Carter, Anndria Cluster, Kylee Gochanour, Danelle Grochocinski, Iwo Gross, Corissa Mantooth, Emily McCallen, Murphy Walters, and Joseph Zigler. In particular, Joeseph Zigler and Kylee Gochanour dedicated dozens of hours of their free time to helping me process snakes, and prepare samples. Similarly, Cynthia Carter, Iwo Gross, Corissa Mantooth, and Emily McCallen helped me not only with research, but also kept me sane (relatively speaking, of course) throughout this process, all of whom I consider lifelong friends. I must also thank Andrew Durso for the iii help and inspiration he has provided me with in the past two years, without him I never would have considered pursuing stable isotope analyses for my thesis. I'm thankful for the faculty of the Biological Sciences Department at Eastern Illinois University and all of their logistical support. In particular, Sandra Baumgartner, Deborah Endsley, Marschelle McCoy, and Megan Przygoda, who simplified my life with their generous help. I owe a special thanks to Mike Masters of the Energy Biosciences Institute at the University of Illinois for his collaboration, and for completing stable isotope analyses on my samples. This study would not have been possible without permission from the Illinois Department of Natural Resources, specifically the personnel Fox Ridge State Park, who also assisted with construction and maintenance of drift fences. Funding was graciously awarded to me through teaching and research assistantships from Eastern Illinois University (EIU), and a Graduate Student Investigator Award and two Research and Creative Activity Grants from the Graduate School at EIU. Finally, I would like to thank my loving boyfriend Clinton Morgeson, my parents, Amanda and Craig Schenning, and the remainder of my family for their constant support, and never failing to let me lose sight of the light at the end of the tunnel. iv TABLE OF CONTENTS List of Tables ..................................................................................................................... vi List of Figures ................................................................................................................... vii Introduction .......................................................................................................................... ! Natural History of Select Invertivorous Snakes ...................................................... 3 Studying Snake