Free-Floating Invasive Fern Affects Freshwater Marsh Ecosystem Structure: Changes to Water Quality and Chemistry, Aquatic Vegetation, Fish, and Invertebrates
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Louisiana State University LSU Digital Commons LSU Doctoral Dissertations Graduate School March 2021 Free-floating Invasive Fern Affects Freshwater Marsh Ecosystem Structure: Changes to Water Quality And Chemistry, Aquatic Vegetation, Fish, and Invertebrates Charles Wahl Louisiana State University and Agricultural and Mechanical College Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_dissertations Part of the Terrestrial and Aquatic Ecology Commons Recommended Citation Wahl, Charles, "Free-floating Invasive Fern Affects Freshwater Marsh Ecosystem Structure: Changes to Water Quality And Chemistry, Aquatic Vegetation, Fish, and Invertebrates" (2021). LSU Doctoral Dissertations. 5466. https://digitalcommons.lsu.edu/gradschool_dissertations/5466 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Doctoral Dissertations by an authorized graduate school editor of LSU Digital Commons. For more information, please [email protected]. FREE-FLOATING INVASIVE FERN AFFECTS FRESHWATER MARSH ECOSYSTEM STRUCTURE: CHANGES TO WATER QUALITY AND CHEMISTRY, AQUATIC VEGETATION, FISH, AND INVERTEBRATES A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Doctor of Philosophy in The School of Renewable Natural Resources by Charles Wahl B.S., Clemson University, 2010 M.S., University of Maryland, Baltimore County, 2016 May 2021 ACKNOWLEDGMENTS I would like to say thank you to many people, funders and organizations for making my dissertation possible. First and foremost, I would like to say how grateful I am for my advisors Dr. Michael Kaller and Dr. Rodrigo Diaz. I received tremendous amount of help, feedback and encouragement from both of you, all of which have helped me grow into a better scientist and professional. I definitely would not be where I am without the experience and knowledge gained from working under you guys. I am also thankful to my committee members Dr. William Kelso, Dr. Christopher Mudge, and Dr. Vincent Wilson for their assistance and advisement guiding me through the program. Thank you to all the professors and staff along the way who have helped me learn and expand my knowledge of how the natural world operates. A great amount of thanks for my family and friends, who have displayed nothing but support for me and my ventures. Your assistance and encouragement have kept me going through difficult times. Special thanks to the band Phish, whose music brings so much happiness and joy to my life. Traveling around the country for shows, gathering with friends I love, for the music we love, are some of the best moments of my life, and looking forward to the next tour has kept me going through hard times. I would like to thank the following people for field and laboratory assistance, Seth Spinner, Fatima Nguyen, Debra Kelly, Keyla Pruett, Emily Passman, Giovana Matos, Rachel Watson, Darren Richard, Chad Courville, Mariah Taylor, Erin Thayer, Melanie Holton, and Shea Johnson. Thank you to Miami Corporation for allowing me access to conduct a study on your property. Thanks to Louisiana Department of Wildlife and Fisheries, Delta Waterfowl, and Mid- South Aquatic Plant Management Society for providing funds. ii TABLE OF CONTENTS ACKNOWLEDGMENTS ..................................................................................................... ii LIST OF TABLES ................................................................................................................. iv LIST OF FIGURES ............................................................................................................... v ABSTRACT ........................................................................................................................... vii CHAPTER 1. GENERAL INTRODUCTION ...................................................................... 1 Background ................................................................................................................ 1 CHAPTER 2. INVASION OF FLOATING FERN ALTERS FRESHWATER MACROINVERTEBRATE COMMUNITY STRUCTURE WITH IMPLICATIONS FOR BOTTOM-UP PROCESSES ................................................................................................. 4 Introduction ................................................................................................................ 4 Methods...................................................................................................................... 5 Results ........................................................................................................................ 8 Discussion .................................................................................................................. 13 Conclusion ................................................................................................................. 18 CHAPTER 3. NUTRIENTS ENHANCE THE NEGATIVE IMPACT OF AN INVASIVE FLOATING PLANT ON WATER QUALITY AND A SUBMERGED MACROPHYTE . 19 Introduction ................................................................................................................ 19 Methods...................................................................................................................... 20 Results ........................................................................................................................ 22 Discussion .................................................................................................................. 28 CHAPTER 4. INVASIVE FLOATING FERN LIMITS AERIAL COLONIZATION AND ALTERS COMMUNITY STRUCTURE OF AQUATIC INSECTS .................................... 31 Introduction ................................................................................................................ 31 Methods...................................................................................................................... 32 Results ........................................................................................................................ 34 Discussion .................................................................................................................. 37 CHAPTER 5. GENERAL CONCLUSION .......................................................................... 41 Synthesis .................................................................................................................... 41 APPENDIX A. SUPPLEMENTAL DATA FOR CHAPTER 2 ............................................ 44 APPENDIX B. SUPPLEMENTAL DATA FOR CHAPTER 4 ............................................ 46 LIST OF REFERENCES ....................................................................................................... 51 VITA ...................................................................................................................................... 69 iii LIST OF TABLES 2.1. Mean water quality parameters collected between habitat types for each sampling month (±SE) ........................................................................................................................... 9 2.2. Mean light intensity [LUX (±SD)] measurements between giant salvinia and submerged aquatic vegetation (SAV) habitat for all sampling months ................................. 9 2.3. Multivariate generalized linear model results (deviation test statistic (Dev., p) of abundance examining taxa response to habitat and month .................................................... 12 2.4. Taxon scores for non-metric multidimensional scaling (NMDS) axes 1 and 2. Values indicate position along each axis ........................................................................................... 14 3.1. Mean percent nitrogen and carbon (±SD) in salvinia tissue for the initial cover and nutrients, low (0), medium (3), and high (8 mg N L-1) treatments. Samples were collected initially (0), halfway (3) and at completion of the study (6 weeks) (n = 4) ........... 26 3.2. Linear mixed model and generalized linear mixed models estimates of mean values for dissolved oxygen (DO, mg/L), pH, specific conductance (µS), and light intensity (LUX) at 10 cm depth with, lower and upper 95% confidence limits (CL) among initial salvinia cover, 0, 5 and 20%, and nutrients, low (0), medium (3) and high (8 mg N L-1) ..... 26 4.1. Mean values (±SD) of dissolved oxygen (DO), pH, specific conductance (Cond), and temperature (Temp) in 0, 25, 50, or 100% salvinia cover in field mesocosms located in Baton Rouge, Louisiana ......................................................................................................... 35 4.2. Mean light intensity (lux) (±SD) measured in 0, 25, 50 or 100% salvinia coverages at various depths from mesocosms located in Baton Rouge, Louisiana .................................... 36 4.3. Multivariate generalized linear model results (deviation test statistic, p-value) of insect abundance examining taxa response to salvinia cover and month .............................. 37 iv LIST OF FIGURES 2.1. Sampling sites containing giant salvinia and submerged aquatic vegetation (SAV) in Cameron Parish, Louisiana .................................................................................................... 6 2.2. Mean abundance of macroinvertebrates per gram of dry mass (±SE) in giant salvinia (salvinia) and submerged aquatic vegetation (SAV) habitat