Aquatic macroinvertebrate communities and diversity patterns in the Northern Prairie Pothole Region by Jennifer Erin Gleason A thesis presented to the University of Waterloo in fulfillment of thesis requirements for the degree of Master of Science in Biology Waterloo, Ontario, Canada, 2017 © Jennifer Erin Gleason 2017 Author’s Declaration I hereby declare that I am the sole author of this thesis. This is a true copy of the thesis, including any required final revisions, as accepted by my examiners. I understand that my thesis may be made electronically available to the public. ii Abstract The Northern Prairie Pothole Region (NPPR) of Alberta, Canada contains numerous shallow marshes that serve as important habitat for wildlife and provide many essential ecosystem services. Many of these pothole wetlands have been destroyed or degraded by agricultural activity, prompting research into their condition and management. Aquatic macroinvertebrates are frequently used as indicators of environmental condition in rivers and lakes, but their effectiveness as indicators in prairie pothole marshes is not clear. I discovered that, contrary to my predictions, macroinvertebrate richness and community composition at family-level resolution do not respond to land use. Instead, macroinvertebrate community composition in pothole marshes is structured primarily by hydroperiod, which ranges from temporary, through seasonal and semi-permanent, to permanent marsh classes. I discovered that the macroinvertebrate abundance, diversity and community composition differed significantly among wetland permanence classes, and that macroinvertebrates exhibited a nested community composition along this hydrological gradient. In other words, macroinvertebrates in temporary wetlands were not unique, but rather subsets of the taxa occupying more permanent wetlands. I also looked at macroinvertebrate functional groups (desiccation strategies, functional feeding groups and behavioural guilds). I discovered that the subset of taxa occupying temporary marshes were those that possess strategies for surviving the drawdown period, such as drought resistant stages or the ability to disperse to larger water bodies. Most functional feeding groups and behavioural guilds were more abundant in permanent wetlands; however, variation existed that was unrelated to hydroperiod and might be due to differences in aquatic vegetation. Like abundance, both alpha and gamma diversity were highest in permanent marshes; however, beta diversity was highest in temporary mashes. This suggests that alpha and gamma diversities are constrained in pothole marshes by the tolerance of taxa to periodic desiccation, in keeping with the species-sorting model of community assembly. However, in temporary marshes the assembly process is reinitiated frequently, and is therefore more strongly influenced by the stochastic aspects of dispersal. This yields a higher beta diversity or taxon turnover among temporary marshes and is in line with neutral theory. This stresses the importance of both local and regional factors in shaping biodiversity and provides insight into the community ecology of wetland macroinvertebrates and their associations with environmental variables. iii Acknowledgements Funding in support of this research came from Alberta Innovates: Energy and Environment Solutions – Water Innovation Program and the Ontario Graduate Scholarship program. I would like to thank Dr. Rebecca Rooney for her guidance and dedication. You provided me with a wonderful opportunity and I am grateful for your mentorship and encouragement. I would also like to thank my committee members, Dr. Barry Warner and Dr. Jon Witt for their invaluable advice throughout the course of this project and Dr. Derek Robinson for his assistance in locating study sites. I am extremely thankful for the tireless efforts of the Alberta field crew (Daina Anderson, Brandon Baer, Matt Bolding, Graham Howell, Adam Kraft, Nicole Meyers and Heather Polan) who helped collect the macroinvertebrates and other environmental variables. Most of the study wetlands were located on private land and I am grateful to the many Albertan land owners for allowing us access to these sites. Thank you to co-op students Jacob Basso, Emma Hawley-Yan, Hufsa Khan and Cheryl Reyes for their hard work in assisting me sort and identify hundreds of macroinvertebrate samples. I would like to thank Courtney Robichaud who provided me with feedback and advice throughout this project, as well as the entire Rooney lab for their motivation and comradery. I would also like to thank my wonderful parents for instilling in me a love of nature and encouraging me to pursue my goals. They introduced me to my first wetlands as a child where I discovered a talent for catching insects and frogs. Finally, thank you to Anton Baglaenko for your kindness, support and encouragement. iv Table of Contents Author’s Declaration ....................................................................................................................... ii Abstract .......................................................................................................................................... iii Acknowledgements ........................................................................................................................ iv Table of Contents ............................................................................................................................ v List of Figures ................................................................................................................................. x List of Tables ................................................................................................................................. xi List of Abbreviations .................................................................................................................... xii 1. Introduction and literature review ...................................................................................... 1 1.1 Importance of Northern Prairie Pothole Region marshes ..................................................... 1 1.2 NPPR and Alberta’s Natural Regions ................................................................................... 2 1.3 Hydrology and permanence classes ...................................................................................... 3 1.4 Agricultural effects ............................................................................................................... 5 1.5 Resource management .......................................................................................................... 6 1.6 Aquatic macroinvertebrates as bioindicators ........................................................................ 7 1.7 Aquatic macroinvertebrate ecology ...................................................................................... 8 1.8 Community assembly.......................................................................................................... 10 1.9 Thesis objectives ................................................................................................................. 11 1.10 Tables ................................................................................................................................ 15 2. Aquatic macroinvertebrates are poor indicators of agriculture in NPPR wetlands .... 18 v 2.1 Introduction ......................................................................................................................... 18 2.1.1 Objectives and hypothesis............................................................................................ 21 2.2 Methods............................................................................................................................... 21 2.2.1 Field collection and sample preparation ...................................................................... 21 2.2.2 Statistical analysis ........................................................................................................ 23 2.3 Results ................................................................................................................................. 25 2.4 Discussion ........................................................................................................................... 26 2.5 Figures................................................................................................................................. 30 3. Cyclic drying determines macroinvertebrate community structure in Northern Prairie Potholes ........................................................................................................................................ 34 3.1 Introduction ......................................................................................................................... 34 3.1.1 Objectives and hypotheses ........................................................................................... 39 3.2 Methods............................................................................................................................... 40 3.2.1 Study region and wetland selection ............................................................................. 40 3.2.2 Macroinvertebrate sampling ........................................................................................ 41 3.2.3 Hydroperiod and water chemistry ................................................................................ 42 3.2.4 Vegetation area ............................................................................................................ 43 3.2.5 Macroinvertebrate sorting and identification ............................................................... 43 3.2.6 Functional groups......................................................................................................... 43 3.2.7 Statistical analysis ........................................................................................................ 44 vi 3.3 Results ................................................................................................................................. 45 3.3.1 Macroinvertebrate community composition ................................................................ 46 3.3.2 Functional traits ........................................................................................................... 47 3.4 Discussion ........................................................................................................................... 48 3.4.1 Differences in community composition among permanence classes .......................... 50 3.4.2 Desiccation strategies and functional groups ............................................................... 52 3.4.3 Conclusions and future work ....................................................................................... 54 3.5 Figures................................................................................................................................. 57 3.6 Tables .................................................................................................................................. 63 4. Local and regional diversity patterns of aquatic macroinvertebrates in temporary and permanent wetlands .................................................................................................................... 66 4.1 Introduction ......................................................................................................................... 66 4.1.1 Objectives and hypotheses ........................................................................................... 69 4.2 Methods............................................................................................................................... 70 4.2.1 Macroinvertebrate collection and identification .......................................................... 70 4.2.2 Data analysis ................................................................................................................ 71 4.3 Results ................................................................................................................................. 73 4.4 Discussion ........................................................................................................................... 74 4.4.1 Measures of diversity ................................................................................................... 74 4.4.2 Community assembly................................................................................................... 79 vii 4.4.3 Macroinvertebrate abundance and evenness ................................................................ 80 4.4.4 Implications for conservation ...................................................................................... 81 4.4.5 Conclusions and future directions ................................................................................ 82 4.5 Figures................................................................................................................................. 83 5. Synthesis and conclusions .................................................................................................. 85 5.1 Research findings ................................................................................................................ 86 5.2 Taxonomic resolution ......................................................................................................... 88 5.3 Implications and future work .............................................................................................. 89 5.4 Significance and conclusions .............................................................................................. 92 6. References ............................................................................................................................. 93 7. Appendices .......................................................................................................................... 124 7.1 Appendix 1 – Natural Regions ordination ........................................................................ 124 7.2 Appendix 2 – Taxa and functional group list.................................................................... 125 7.3 Appendix 3 – Site information .......................................................................................... 127 7.4 Appendix 4 – Environmental variables in NPPR wetlands .............................................. 130 7.5 Appendix 5 – NMDS joint plot scores for environmental variables ................................ 131 7.6 Appendix 6 – Wetland sites by Natural Region and permanence class ............................ 133 7.7 Appendix 7 – Alpha, beta and gamma diversity ............................................................... 134 7.8 Appendix 8 – Scree plot example ..................................................................................... 135 7.9 Appendix 9 – Residual plot example ................................................................................ 136 viii 7.10 Appendix 10 – Benthic core data .................................................................................... 137 ix List of Figures Figure 2-1 A map of the NPPR with 64 wetland sites with varying land use intensity ............... 30 Figure 2-2 A diagram displaying the two major zones we sampled in a wetland (if both were present): the emergent zone and the open water zone. In each zone, a water column and a vegetation quadrat were employed to collect macroinvertebrates ................................................ 31 Figure 2-3 Non-metric multidimensional scaling (NMDS) ordination of macroinvertebrate taxa by disturbance bin ......................................................................................................................... 32 Figure 2-4 Bar charts displayed a) average macroinvertebrate abundance; b) average Simpson’s Dominance and c) average taxa richness for each disturbance bin .............................................. 33 Figure 3-1 A map of the NPPR with 87 wetland sites with varying hydroperiods ...................... 57 Figure 3-2 Non-metric multidimensional scaling (NMDS) ordinations of macroinvertebrate community composition by permanence class ............................................................................. 59 Figure 3-3 Non-metric multidimensional scaling (NMDS) ordinations of macroinvertebrate desiccation strategies by permanence class .................................................................................. 60 Figure 3-4 Non-metric multidimensional scaling (NMDS) ordination of macroinvertebrate functional feeding groups by permanence class ........................................................................... 61 Figure 3-5 Non-metric multidimensional scaling (NMDS) ordinations of macroinvertebrate behavioural guilds by permanence class ....................................................................................... 62 Figure 4-1 Bar charts displaying average a) average total abundance per m2 of macroinvertebrates; b) average community evenness (measured as Simpson’s diversity) and c) average alpha diversity for each permanence class. ..................................................................... 83 Figure 4-2 Bar charts displayed a) average alpha diversity; b) average beta diversity (determined using a Bray-Curtis dissimilarity matrix) and c) gamma diversity for each permanence class .... 84 x