The Utility of Growth Form for Predicting and Evaluating Aquatic Plant Nutrient Relations
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THE UTILITY OF GROWTH FORM FOR PREDICTING AND EVALUATING AQUATIC PLANT NUTRIENT RELATIONS by Christopher Dean Tyrrell Master of Science, Iowa State University, 2008 Bachelor of Science, University of Wisconsin-Stevens Point, 2005 A Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in the Graduate Academic Unit of Biology Supervisors: Patricia A. Chambers, Ph.D., Water Science & Technology, Environment Canada and Biology Department, University of New Brunswick Joseph M. Culp, Ph.D., Water Science & Technology, Environment Canada and Biology Department, University of New Brunswick Examining Board: Stephen B. Heard, Ph.D., Biology Department, University of New Brunswick Fredericton John A. Kershaw, Ph.D., Faculty of Forestry and Environmental Management, University of New Brunswick Fredericton Jeff E. Houlahan, Ph.D., Biology Department, University of New Brunswick Saint John External Examiner: Matthew T. O’Hare, Ph.D., Centre for Ecology & Hydrology, Natural Environment Research Council, United Kingdom This dissertation is accepted by the Dean of Graduate Studies THE UNIVERSITY OF NEW BRUNSWICK April, 2015 ©Christopher D. Tyrrell, 2015 Abstract My dissertation focuses on the role of agricultural nutrient enrichment in structuring aquatic plant communities in Southern Manitoba, Canada, and changes in nutrient cycling resulting from changes in vegetation structure. Built around the “holy grail” framework of community ecology, which describes connections between the environment and ecosystem services or function as mediated by the traits of the biotic community, I explore the linkages between nutrient enrichment and aquatic plants of prairie streams focusing on species growth form (morphology) as a proxy for a suite of co-varying individual traits. I found that plant morphology interacted with environmental factors to determine which growth forms predominated in a stream: plant community shifts from being dominated by species with a submerged morphology to a community dominated by an emergent morphology as nutrient concentrations increase. I show how this pattern allows plant growth form to be used as an indicator of stream nutrient status. Further, I found that plants with similar growth forms share similar physiological features. Emergent plants have lower tissue nutrient concentrations per unit biomass and thus transfer fewer nutrients per unit biomass from the sediment to the water column than submerged plants. My work also includes a phylogenetic thread that brings novel insight: species at sites with higher nutrients all tend to be clustered in a few branches of the plant phylogeny whereas stream sites with lower nutrients have species from a diverse mixture of phylogenetic lineages. I used plant phylogeny to examine whether evolutionary history is related to tissue nutrient concentration and found the influence is mostly attributable to phenotype. These findings hint at the possibility of alternative stable states for prairie stream vegetation: a high nutrient emergent community and a ii low nutrient submerged community. These alternative states are comparable to those found in shallow lakes, where high nutrient conditions are dominated by algal growth and bring about turbid water, whereas lower nutrients are characterized by clear water and abundant macrophyte growth. The nutrient transferring functionality of these two vegetation states should also differ, but specific quantities transferred would dependent on the proportion of biomass of each growth form. iii Acknowledgements To all those who have aided me in the quest to write this “bucket of blood, sweat and tears”: Jessica Orlofske, Patricia Chambers, Joseph Culp; David Arminini, Donald Baird, Lars Båstrup-Spohr, Glenn Benoy, Sebastian Birk, Gart Bishop, Margaret Blacquier, Bob Brua, Justin Chase, Rose Chase, Tom Clair, Rose Comeau, Julie Corriveau, Jeff Crocker, Rick Cunjak, Allen Curry, Colin Curry, Ian Delorme, Zoey Duggen, Rob Ellis, Teresa Ferriera, Bruce Ford, Kate Frego, Don Flaten, Nathaniel Flaten, Laura Grace, Gail Grey, Daryl Halliwell, Kristie Heard, Steve Heard, Dave Hryn, Antti Kanninen, Karen Kidd, Melanie Lawson, Jen Lento, David Lobb, Heather Loomer, Eric Luiker, Balázs Lukács, Ross MacKay, Angella Mercer, Stephanie Melles, Liz Mills, Wendy Monk, Armin Namayandeh, Laura Noel, Rakesh Rajput, Kurt Samways, Kaj Sand-Jensen, Gary Saunders, David Soto, Katherine Standen, Alexa (Alexander) Trusiak, Jason Vanrobaeys, Adam Yates, Naomi Yuen, Bernie Zebarth; Agriculture and Agri-food Canada Potato Research Centre, Environment Canada, University of Manitoba Herbarium (WIN), University of New Brunswick Herbarium (UNB), and Mary, Tom, and Sarah Tyrrell, Grandpa McNutt, Grandma Tyrrell, Ted, John, and Susan Tyrrell: I thank you. I have made an attempt to acknowledge those who have helped me in my endeavor, but the work represented by this (or any other) dissertation is a detailed and complicated affair. I apologize to anyone who has provided me with guidance and is absent from this list, it is a fault of my memory and not of your importance. iv Table of Contents Abstract ........................................................................................................................... ii Acknowledgements ....................................................................................................... iv Table of Contents ............................................................................................................ v Table of Figures .............................................................................................................. x Table of Tables ............................................................................................................. xiv Chapter 1 - General Introduction ................................................................................... 1 1.1 Background ............................................................................................................. 1 1.2 Objectives ............................................................................................................... 6 1.3 Structure of the Dissertation .................................................................................... 7 1.4 Significance ........................................................................................................... 10 References .................................................................................................................. 11 Tables and Figures ..................................................................................................... 16 Chapter 2 - Aquatic plant community response to nutrient-producing human activities in southern Manitoba, Canada .................................................................... 19 Abstract ....................................................................................................................... 19 2.1 Introduction ........................................................................................................... 19 2.2 Methods ................................................................................................................ 22 2.2.1 Study sites ...................................................................................................... 22 2.2.2 GIS data ......................................................................................................... 23 v 2.2.3 Statistical Analyses ........................................................................................ 25 2.3 Results .................................................................................................................. 29 2.3.1 GIS analysis of nutrient emitting activities ...................................................... 29 2.3.2 Site surveys .................................................................................................... 30 2.3.3 Biotic-abiotic relationships .............................................................................. 32 2.4 Discussion ............................................................................................................. 33 Acknowledgements ..................................................................................................... 38 References .................................................................................................................. 39 Tables and Figures ..................................................................................................... 46 Chapter 3 - Using traits to generalize European aquatic plant trophic indices for use in Canada ................................................................................................................ 55 Abstract ....................................................................................................................... 55 3.1 Introduction ........................................................................................................... 56 3.2 Methods ................................................................................................................ 59 3.2.1 Data sources .................................................................................................. 59 3.2.2 Taxonomic identity, growth form and trophic affinity ...................................... 61 3.2.3 Site scores ...................................................................................................... 62 3.2.4 Analyses ........................................................................................................