University of New Hampshire University of New Hampshire Scholars' Repository Doctoral Dissertations Student Scholarship Spring 2012 Ecological effects of ditching and ditch-plugging in New England salt marshes Robert E. Vincent University of New Hampshire, Durham Follow this and additional works at: https://scholars.unh.edu/dissertation Recommended Citation Vincent, Robert E., "Ecological effects of ditching and ditch-plugging in New England salt marshes" (2012). Doctoral Dissertations. 661. https://scholars.unh.edu/dissertation/661 This Dissertation is brought to you for free and open access by the Student Scholarship at University of New Hampshire Scholars' Repository. It has been accepted for inclusion in Doctoral Dissertations by an authorized administrator of University of New Hampshire Scholars' Repository. For more information, please contact [email protected]. ECOLOGICAL EFFECTS OF DITCHING AND DITCH-PLUGGING IN NEW ENGLAND SALT MARSHES BY ROBERT E. VINCENT B.A. University of Rhode Island, 1987 M.S. Antioch University, 1996 DISSERTATIOiN Submitted to the University of New Hampshire In Partial Fulfillment of The Requirements for the Degree of Doctor of Philosophy In Earth and Environmental Science May, 2012 UMI Number: 3525069 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. ttswWioft FtoMsh«i UMI 3525069 Published by ProQuest LLC 2012. Copyright in the Dissertation held by the Author. Microform Edition © ProQuest LLC. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code. ProQuest LLC 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106-1346 ALL RIGHTS RESERVED ©2012 Robert E. Vincent This dissertation has been examined and approved. Dissertation Director. Dr. David M Burdick Research Associate Professor. Department of Natural Resources and the Environment Dr. Michele Dionne. Research Director. We Dr. Erik A. Hobbie. Research Associate Professor. Institute for the Study of Earth. Oceans, and Space / Dr. Tbomas D. Lee. Associate Professor. Department of Natural Resources and the Environment Department of Natural Resources and the Environment Date DEDICATION This dissertation is dedicated to my family; and especially to Beth for her patience and support during this process. iv ACKNOWLEDGEMENTS I'd like to thank my dissertation advisor, Dr. David Burdick, for taking me on as a student and for his guidance throughout my Ph.D. work; my committee members, Dr. Michele Dionne, Dr. Erik Hobbie, Dr. Tom Lee, and Dr. Fred Short for their advice during my time at the University of New Hampshire (UNH); and Dr. Michele Dionne for her guidance during my fellowship at the Wells National Estuarine Research Reserve (The Wells Reserve). I'd also like to thank students and faculty at the UNH Jackson Estuarine Laboratory for their help with field work, especially Alyson Eberhardt, Chris Peter, and Dr. Greg Moore, as well as staff at The Wells Reserve. Additional thanks go to Dr. Erik Hobbie and Andy Ouimette at the UNH Stable Isotope Laboratory for their assistance with stable isotope processing; and Dr. Ray Konisky at The Nature Conservancy, Matt Collins at the NOAA Restoration Center, and Beth Lambert and staff at the New Hampshire Coastal Program for help with data collection and use of equipment. Funding for my research at Moody Marsh was provided by the NOAA National Estuarine Research Reserve Graduate Research Fellowship Program. Equipment used in my research was funded in part by the UNH Marine Program. The U.S. Fish and Wildlife Service provided special use permits for work at Chauncey Creek, Moody, and Parker River marshes. Permission to conduct work at Sprague River Marsh was provided by Bates College and The Nature Conservancy. V TABLE OF CONTENTS DEDICATION iv ACKNOWLEDGEMENTS v LIST OF TABLES ix LIST OF FIGURES x ABSTRACT xiv CHAPTER PAGE I. INTRODUCTION 1 Background 1 Objectives 15 Organization of the Dissertation 24 II. DITCHING AND DITCH-PLUGGING IN NEW ENGLAND SALT MARSHES: EFFECTS ON HYDROLOGY, ELEVATION, AND SOIL CHARACTERISTICS 25 Abstract 25 Introduction 25 Materials and Methods 26 Results 37 Discussion 53 Conclusion 66 vi CHAPTER PAGE III. DITCHING AND DITCH-PLUGGING IN NEW ENGLAND SALT MARSHES: EFFECTS ON PLANT COMMUNITIES 68 Abstract 68 Introduction 69 Materials and Methods 70 Results 74 Discussion 86 Conclusion 97 IV. FISH PRODUCTIVITY AND TROPHIC TRANSFER IN CREATED AND NATURALLY-OCCURRING SALT MARSH HABITAT 100 Abstract 100 Introduction 101 Materials and Methods 105 Results 117 Discussion 136 Conclusion 153 V. CONCLUSION 156 Historic and Current Hydrologic Alterations 156 Ecosystem Response to Ditching 157 Ecosystem Response to Natural Creek Hydrology 163 Ecosystem Response to Ditch-Plugging 164 vii Ecosystem Response to Natural Pool Hydrology 165 LITERATURE CITED 166 APPENDICES PAGE APPENDIX A MEAN VALUES (± SE) BY MARSH AND HABITAT FOR HYDROLOGY, MARSH SURFACE ELEVATION, AND SOIL CHARACTERISTICS 187 APPENDIX B PLANT CHARACTERISTICS BY MARSH 195 APPENDIX C INVERTEBRATE RICHNESS AND ABUNDANCE BY HABITAT, LOCATION, AND TREATMENT: MOODY MARSH, WELLS, MAINE 205 APPENDIX D INSTITUTIONAL ANIMAL CARE AND USE COMMITTEE APPROVAL LETTERS 214 viii LIST OF TABLES TABLE PAGE 1. ANOVA analysis for hydrology, soils, and marsh surface elevations 37 2. Tidal ranges by habitat 39 3. Correlation matrix for hydrology, soils, and marsh surface elevations 40 4. Marsh surface elevations by habitat 41 5. Hydrology, soils, and elevation discriminant function actual by predicted habitat classification matrix 52 6. Discriminant function values for hydrology, soils, and marsh surface elevations 52 7. Discriminant function scoring coefficients for hydrology, soils, and marsh surface elevations 52 8. Kruskal-Wallis test for plant biomass 76 9. ANOVA results for plant characteristics 77 10. Plant discriminant function actual by predicted habitat classification matrix... 85 11. Discriminant function values for plant characteristics 86 12 Discriminant function scoring coefficients for plant characteristics 87 13. ANOVA for invertebrate community characteristics 124 14. Invertebrate proportional distribution by major taxa and habitat 126 15. Stable isotope values by species 130 16. Regression results for fish g15N and g13C vs. pool water salinity 131 ix LIST OF FIGURES FIGURE PAGE 1. Salt marsh self-maintenance process 3 2. Creek habitat 5 3. Wagon wheel ruts in salt marsh habitat 7 4. Ditch habitat 8 5. Salt marsh grid ditching 9 6. Hay staddle erosion pool formation 11 7. Natural pool habitat 11 8. Ditch-plug plywood reinforcement 12 9. Ditch-plug habitat 13 10. Four-marsh study site location map 15 11. Creek habitat conceptual model 18 12. Ditch habitat conceptual model 19 13. Natural pool habitat conceptual model 20 14. Ditch-plug habitat conceptual model 21 15. Natural pool trophic interaction conceptual model 22 16. Ditch-plug trophic interaction conceptual model 23 17. Three-marsh study site location map 27 18. Parker River Marsh study site 28 19. Chauncey Creek Marsh study site 29 20. Sprague River Marsh study site 31 X FIGURE PAGE 21. Water levels by habitat 38 22. Tidal stage duration curves 39 23. Marsh surface elevations by habitat 41 24. Marsh surface elevations by habitat and distance 42 25. Pore-water salinity by habitat 43 26. Soil redox potential by habitat 44 27. Soil strength by habitat 45 28. Soil strength with depth by habitat 46 29. Soil bulk density by habitat 47 30. Soil carbon storage 48 31. Soil percent organic content 49 32. Discriminant function analysis for hydrology and soil characteristics 51 33. Ditch-plug habitat surface water impoundment and vegetation dieback 59 34. Areas of excess salt accumulation in ditch-plug habitat 61 35. Ditch-plug habitat plant dieback areas colonized by sulfur bacteria and algae mat 75 36. Plant percent cover by habitat 76 37. Plant biomass by habitat 77 38. Plant species richness and diversity by habitat 79 xi FIGURE PAGE 39. Plant species composition by habitat 80 40. Plant composition by habitat, distance, and elevation 81 41. Discriminant function analysis for plant characteristics 84 42. Hummock-hollow topography patterns in ditch-plug habitat 95 43. Moody Marsh study site location map and sample stations 107 44. Moody Marsh fish enclosures and exclosures 108 45. Moody Marsh study design with soil core locations 109 46. Moody Marsh pool physical characteristics 119 47. Natural pool and ditch-plug soil cores 120 48. Fish growth by habitat 121 49. Invertebrate community characteristics 123 50. Invertebrate biomass by habitat 124 51. Invertebrate species richness by habitat 125 52. Invertebrate density by habitat 125 53. Invertebrate abundance by major taxa and habitat 127 54. Invertebrate caloric values 128 55. Stable isotope values (513C and 815N) for vegetation, invertebrates, and fish 131 56. Stable isotope values (813C and 8I5N) for plants by habitat 132 57. Natural pool habitat food web 134 58. Ditch-plug habitat food web 135 xii FIGURE PAGE 59. Ditch habitat observed conditions 158 60. Creek habitat observed conditions 159 61. Ditch-plug habitat observed conditions 160 62. Natural pool habitat observed conditions 161 xiii ABSTRACT ECOLOGICAL EFFECTS OF DITCHING AND DITCH-PLUGGING IN NEW ENGLAND SALT MARSHES by Robert E.