CONFRONTING INCOMPLETE DETECTION TO ADDRESS QUESTIONS ABOUT DISTRIBUTION AND REPRODUCTIVE SEASON FOR FOUR IMPERILED STREAM FISHES by GREGORY B. ANDERSON (Under the Direction of Mary C. Freeman) ABSTRACT Geographical and ecological restrictions are the primary drivers of freshwater fish imperilment within the southeastern United States. To effectively manage existing populations and implement regulatory mechanisms of protection, information on the ecology and distributional patterns of imperiled taxa is needed. In this study, reproductive aspects including spawning behavior, microhabitat use and phenology were recorded for four imperiled percid taxa of the Upper Etowah watershed: the Etowah and Amicalola holiday darters (Etheostoma sp. cf. E. brevirostrum A and B), the Etowah darter (Etheostoma etowahae), and the bridled darter (Percina kusha). While accounting for incomplete detection, the occurrence of the spawning events was modeled according to visit characteristics to determine the duration of the spawning season. Additionally, patterns of spatial variation of the two holiday darter species were studied in an attempt to refine the known geographic range of these species and to identify factors influencing variations in occupancy and detection. INDEX WORDS: Percidae, Etheostoma, Percina, Ulocentra, Nothonotus, Alvordius, Holiday darter, Etowah darter, Bridled darter, Amicalola Creek, Etowah River, Occupancy modeling, Incomplete detection, Information theoretic, Land use CONFRONTING INCOMPLETE DETECTION TO ADDRESS QUESTIONS ABOUT DISTRIBUTION AND REPRODUCTIVE SEASON FOR FOUR IMPERILED STREAM FISHES by GREGORY B. ANDERSON B.A., University of Georgia, 2005 A Thesis Submitted to the Graduate Faculty of the University of Georgia in Partial Fulfillment of the Requirements for the Degree MASTER OF SCIENCE ATHENS, GEORGIA 2009 © 2009 Gregory B. Anderson All Rights Reserved CONFRONTING INCOMPLETE DETECTION TO ADDRESS QUESTIONS ABOUT DISTRIBUTION AND REPRODUCTIVE SEASON FOR FOUR IMPERILED STREAM FISHES by GREGORY B. ANDERSON Major Professor: Mary C. Freeman Committee: Byron J. Freeman James T. Peterson Brett Albanese Electronic Version Approved: Maureen Grasso Dean of the Graduate School The University of Georgia August 2009 iv ACKNOWLEDGMENTS On the eve of the completion of this thesis, it’s hard to believe that what was once a summer job has turned out to be a life changing experience. For this I have two people to thank: Mary and Bud Freeman. It has been a privilege to work with them for the past two and a half years. I cannot even begin to express my gratitude to Mary Freeman. Her patience, pragmatism and knowledge were essential in the completion of this thesis. Not only was she instrumental in the formulation of these research ideas, but she was also extremely helpful in their application. She is a brilliant scientist and a great advisor. Bud Freeman has been an incredible teacher for me. His knowledge of the natural world is truly remarkable and working with him has been a tremendous learning experience. I would also like to thank Brett Albanese and Jim Peterson. Having two people that were not directly involved in the collection of this work provided an invaluable perspective on the application. Their critiques have made this thesis substantially better, and I am extremely grateful for their patience and advice. Three people have been particularly helpful in the completion of this work. Megan Hagler has shown constant support, and her ideas and research have been extremely helpful in directing me. Moreover, without her invaluable field experience, I do not think these projects would have been completed. Seth Wenger has been a role model of sorts for me. His dedication, attention to detail and frankness make him a true joy to work with. Finally, Emily Kutney has shown nothing but strong support for my research endeavors, and without her brilliant editing, this work would be much harder to read. The success of any field-oriented project depends on field assistance, and I have been blessed with some of the best assistants anyone could ask for. I would particularly like to express my thanks to four people: Christina Baker, Nicole Pontzer, Amanda Neese and Rachel Katz. v TABLE OF CONTENTS Page ACKNOWLEDGMENTS................................................................................................................................. iv LIST OF TABLES............................................................................................................................................vii LIST OF FIGURES ........................................................................................................................................... ix CHAPTER 1 Introduction and Literature Review........................................................................................... 1 Literature Cited.................................................................................................................. 4 2 Occupancy Modeling and Estimation of the Etheostoma brevirostrum species complex within the Etowah River System................................................................................................ 6 Introduction........................................................................................................................ 6 Methods.............................................................................................................................. 7 Results .............................................................................................................................. 14 Discussion ........................................................................................................................ 16 Conclusions...................................................................................................................... 21 Literature Cited................................................................................................................ 22 3 Reproductive Aspects of Four Imperiled Darter Taxa of the Etowah River System ........... 33 Introduction...................................................................................................................... 33 Study Site Descriptions ................................................................................................... 34 Methods............................................................................................................................ 35 Results .............................................................................................................................. 39 Discussion ........................................................................................................................ 44 Conclusions...................................................................................................................... 51 Literature Cited ................................................................................................................ 52 vi 4 Management Implications and Conclusions............................................................................ 68 Literature Cited................................................................................................................ 71 APPENDICIES A Information Relevant to Chapter One..................................................................................... 72 The Etowah River System............................................................................................... 72 Information on Target Species........................................................................................ 73 Literature Cited................................................................................................................ 75 B Information Relevant to Chapter Two .................................................................................... 80 C Information Relevant to Chapter Three .................................................................................. 83 vii LIST OF TABLES Table 2.1. Locations of sampling sites within the Etowah River system...................................................... 25 Table 2.2. A priori hypotheses regarding occupancy and quadrat detection patterns for Etheostoma brevirostrum species complex with the Etowah River system ..................................................... 26 Table 2.3. Model structure, deviance, number of parameters (K), relative difference in AICC (ΔAICC) and model weights (wi) for well supported occupancy models (ΔAICC<10) and an intercept-only model for Etheostoma sp. cf. E. brevirostrum A & B ................................................................... 27 Table 2.4. Summary statistics for continuous covariates measured at 40 collection sites ........................... 28 Table 3.1. Study sites for snorkeling observations of holiday darters, Etowah darter and bridled darter... 56 Table 3.2. A priori hypotheses regarding detection and occurrence of spawning for Etheostoma sp. cf. E. brevirostrum A, Amicalola holiday darter, and E. etowahae, Etowah darter.............................. 57 Table 3.3. Model structure, number of parameters (K), relative difference in AICC (ΔAICC) and AIC weights (wi) of well-supported spawning occurrence models (ΔAICC<10) and intercept-only model for Etheostoma sp. cf. E. brevirostrum A, Amicalola holiday darter, and Etheostoma etowahae, Etowah darter ................................................................................................................