Mississippi State University Scholars Junction Theses and Dissertations Theses and Dissertations 4-30-2021 Investigating ecological links between floodplain forests and aquatic communities Conner Owens [email protected] Follow this and additional works at: https://scholarsjunction.msstate.edu/td Recommended Citation Owens, Conner, "Investigating ecological links between floodplain forests and aquatic communities" (2021). Theses and Dissertations. 5130. https://scholarsjunction.msstate.edu/td/5130 This Graduate Thesis - Open Access is brought to you for free and open access by the Theses and Dissertations at Scholars Junction. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of Scholars Junction. For more information, please contact [email protected]. Investigating ecological links between floodplain forests and aquatic communities By TITLE PAGE Conner Owens Approved by: Sandra B. Correa (Major Professor) J. Wesley Neal Scott A. Rush Kevin M. Hunt (Graduate Coordinator) L. Wes Burger (Dean, College of Forest Resources) A Thesis Submitted to the Faculty of Mississippi State University in Partial Fulfillment of the Requirements for the Degree of Master of Science in Wildlife, Fisheries and Aquaculture in the Department of Wildlife, Fisheries and Aquaculture Mississippi State, Mississippi April 2021 Copyright by COPYRIGHT PAGE Conner Owens 2021 Name: Conner Owens ABSTRACT Date of Degree: April 30, 2021 Institution: Mississippi State University Major Field: Wildlife, Fisheries and Aquaculture Major Professor: Sandra B. Correa Title of Study: Investigating ecological links between floodplain forests and aquatic communities Pages in Study: 110 Candidate for Degree of Master of Science While there is a clear link between riparian forests and freshwater organisms, floodplain forests are seldom investigated due to difficulties in sampling structurally complex and periodically inundated habitat. This lack of research has led to large knowledge gaps that hinder our understanding of the conservation value of these unique, complex ecosystems for inland fisheries. Therefore, I aimed to determine how bottomland hardwood forests influence fish taxonomic, functional diversity and food web structure. I hypothesized that fish taxonomic and functional diversity are driven by forest complexity and the aquatic food web structure is driven by terrestrial carbon sources, specifically forest vegetation. Results indicated a higher taxonomic diversity and functional richness in the floodplain forest and that this forest type provides thermal refugia for fish assemblages. Contrary to my prediction, phytomicrobenthos were a primary carbon production source driving some or all of the aquatic food web in a complex floodplain–river system. Key words: food web, diversity, bottomland hardwood forest, stable isotopes, fish DEDICATION I want to dedicate this research to my parents Tom and Meredith Owens, my little brother Dillon Owens, and my closest friends David, Ryan, Kevin, Turner, and Zack. Their enthusiasm for the outdoors inspires me every day. I would also like to dedicate this to my sweetheart Erica Claycomb for standing by my side every step of the way. ii ACKNOWLEDGEMENTS I want to express my sincere gratitude to those who assisted with this research. First, I would like to acknowledge Dr. Sandra Correa for giving me this once in a lifetime opportunity and for her undivided attention and guidance for this research. I would also like to acknowledge my committee members Dr. Scott Rush and Dr. Wes Neal for their time and assistance making this project a reality. Additionally, I would like to acknowledge Dr. Michael Polito and his lab for analyzing my stable isotope samples, Matt Wagner of the MDWFP for sharing distribution data of fishes of the Pascagoula River Drainage, and the Ward Bayou WMA staff for providing housing and equipment storage. This project would also have not been possible without assistance from Dr. Joshua Granger and Clayton Hale from the Department of Forestry and the fantastic undergraduate research assistants and volunteers along the way. This project was funded by the Eppley Family Foundation for Research (to Dr. Correa), the Forest and Wildlife Research Center at Mississippi State University (to Dr. Correa and Owens), Sigma Xi (to Owens), and the MS Chapter of the American Fisheries Society (to Owens). iii TABLE OF CONTENTS DEDICATION ................................................................................................................................ ii ACKNOWLEDGEMENTS ........................................................................................................... iii LIST OF TABLES ......................................................................................................................... vi LIST OF FIGURES ..................................................................................................................... viii CHAPTER I. ROLE OF FLOODPLAIN FORESTS IN SUPPORTING FISH TAXONOMIC AND FUNCTIONAL DIVERSITY .....................................................................1 Abstract ..............................................................................................................................1 Introduction .......................................................................................................................2 Methods .............................................................................................................................4 Study Area ...................................................................................................................4 Field Data Collection ...................................................................................................4 Data Analyses ..............................................................................................................7 Taxonomic Diversity .............................................................................................7 Results .............................................................................................................................11 Taxonomic Diversity .................................................................................................11 Low Hydrological Period ....................................................................................11 High Hydrological Period ....................................................................................13 Functional Diversity ..................................................................................................14 Low Hydrological Period ....................................................................................14 High Hydrological Period ....................................................................................15 Discussion ........................................................................................................................16 Taxonomic Diversity .................................................................................................16 Functional Diversity ..................................................................................................20 II. ROLE OF FLOODPLAIN FORESTS AS AN ENERGY SOURCE TO AQUATIC CONSUMERS .................................................................................59 Abstract ............................................................................................................................59 Introduction .....................................................................................................................60 Methods ...........................................................................................................................63 Study Area .................................................................................................................63 Field Data Collection .................................................................................................63 iv Laboratory Data Collection .......................................................................................66 Data Analysis .............................................................................................................68 Results .............................................................................................................................70 Discussion ........................................................................................................................71 III. A SPECIES–RICH DRAINAGE: OCCURRENCE AND HABITAT ASSOCIATIONS OF FISHES IN THE PASCAGOULA RIVER SYSTEM .............................................................................................................84 Abstract ............................................................................................................................84 Introduction .....................................................................................................................84 Methods ...........................................................................................................................85 Study Area .................................................................................................................85 Data Collection ..........................................................................................................86 Results .............................................................................................................................87