IMPACTS OF A FLOOD PULSING HYDROLOGY ON PLANTS AND INVERTEBRATES IN RIPARIAN WETLANDS A dissertation submitted to Kent State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy by Maureen K. Drinkard August 2012 Dissertation written by Maureen K. Drinkard B.S., Kent State University, 2003 Ph.D., Kent State University, 2012 Approved by ___Ferenc de Szalay_, Chair, Doctoral Dissertation Committee ___Mark Kershner_______, Members, Doctoral Dissertation Committee _____Oscar Rocha________, ____Mandy Munro-Stasiuk_, Accepted by _____James Blank______, Chair, Department of Biological Sciences ______Raymond Craig___, Dean, College of Arts and Sciences ii TABLE OF CONTENTS LIST OF FIGURES ............................................................................................................... vi LIST OF TABLES ................................................................................................................. vii ACKNOWLEDGEMENTS .................................................................................................... x CHAPTER I. INTRODUCTION ................................................................................................ 1 Dissertation Goals ............................................................................................. 1 Definition of the Flood Pulse Concept .............................................................. 2 Ecological and economic importance ............................................................... 3 Impacts of environmental characteristics in riparian wetlands ....................... 5 Dissolved oxygen and desiccation ........................................................ 5 Chemical conditions .............................................................................. 6 Sedimentation, erosion and deposition ............................................... 6 Effects of flood pulsing on biota ....................................................................... 7 Plant adaptations and responses to abiotic stresses ........................... 7 Flooding, dissolved oxygen and desiccation ............................. 7 Erosion and deposition ............................................................. 9 Invertebrate responses to abiotic stresses ....................................................... 10 Flooding, dissolved oxygen and desiccation ............................. 10 Erosion and deposition ........................................................... 17 II. USING MESOCOSM EXPERIMENTS TO TEST RESPONSES OF PLANT AND INVERTEBRATES TO FLOOD PULSING Abstract ........................................................................................................... 19 Introduction ..................................................................................................... 20 Methods .......................................................................................................... 24 Study site ............................................................................................. 24 Physicochemical measurements ......................................................... 28 Plant and algae communities .............................................................. 29 Aquatic invertebrates .......................................................................... 31 Statistical analyses ............................................................................... 32 Results ............................................................................................................. 33 Abiotic conditions ................................................................................ 33 Aquatic invertebrates in the permanent pool .................................... 39 Plant communities in the permanent pool ......................................... 43 Plant communities in the Intermittently Flooded Zone ..................... 43 iii Discussion ........................................................................................................ 54 Impacts of flooding in the IFZ.............................................................. 54 Impacts of flooding in the permanent pool ........................................ 57 Management implications .................................................................. 59 Acknowledgements ......................................................................................... 61 Appendix A ...................................................................................................... 62 III. ZONATION OF PLANT COMMUNITIES CAUSED BY HYDROLOGICAL STRESSES IN HEADWATER RIPARIAN WETLANDS Abstract ........................................................................................................... 69 Introduction ..................................................................................................... 71 Methods .......................................................................................................... 74 Study site ............................................................................................. 74 Design of hydrology treatments and plant sampling ......................... 75 Statistical analysis ................................................................................ 77 Results ............................................................................................................. 79 Abiotic conditions ................................................................................ 79 Plant community responses ................................................................ 84 Discussion ........................................................................................................ 119 Zonation responses in the plant community ...................................... 119 Management implications ................................................................... 124 Acknowledgements ......................................................................................... 127 IV. USING MESOCOSMS TO TEST IF FLOOD PULSING AFFECTS EMERGENCE OF AQUATIC INSECTS IN HEADWATER WETLANDS Abstract ........................................................................................................... 128 Introduction ..................................................................................................... 129 Methods .......................................................................................................... 132 Study site ............................................................................................. 132 Experimental design ............................................................................ 134 Hydrology ............................................................................................ 134 Adult insect emergence ...................................................................... 135 Statistical analysis ................................................................................ 136 Results ............................................................................................................. 137 Hydrology ............................................................................................. 137 Invertebrate communities ................................................................... 140 Multivariate community analysis ........................................................ 145 Discussion ........................................................................................................ 156 Overall implications ............................................................................. 163 Acknowledgements ......................................................................................... 165 iv V. THE IMPORTANCE OF COARSE WOODY DEBRIS AS INVERTEBRATE MICROHABITAT IN HEADWATER FLOODPLAINS Abstract ........................................................................................................... 166 Introduction ..................................................................................................... 168 Study objectives and hypotheses........................................................ 172 Methods ............................................................................................................ 173 Study site ............................................................................................... 173 Experimental design .............................................................................. 174 Statistical analysis .................................................................................. 176 Results ............................................................................................................... 177 Soil environmental conditions .............................................................. 177 Plant community responses .................................................................. 178 Invertebrate community analysis ......................................................... 181 Discussion .......................................................................................................... 192 Acknowledgements ........................................................................................... 198 VI. SYNTHESIS AND DISCUSSION Synthesis ............................................................................................................ 199 Impact of flood pulsing on biota in headwater wetlands ................................. 201 Positive impacts of flood pulsing .........................................................