Biodiversity: Illustrations of Some Concepts, Causes, and Consequences
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AN ABSTRACT FOR THE DISSERTATION OF Roland B. Russell for the degree of Doctor of Philosophy in Zoology presented on April 14, 2005. Title: Biodiversity: Illustrations of Some Concepts, Causes, and Consequences. Abstract approved: Redacted for Privacy Bruce A. Menge Jane Lubchenco Careful analysis and thoughtful synthesis will be necessary for expanding the envelope of ecological understanding. This work is my attempt at communicating both of these, in relation to three questions about our understanding of the structure and dynamics of biological diversity. These questions focus on a) advancing our understanding of the relations of organismal form and physiological process, b) explaining the overwhelming influence of ecological context on the relationship between local ecological processes and regional evolution and dispersal processes in driving local species richness patterns, and c) demonstrating the causal effect of biological trait diversity on community photosynthetic processes. Chapter two addresses how we conceptualise diversity, and concludes that although simple (i.e., univariate) morphologically- based functional group models for macroalgae are not functionally predictive, morphology does play a key role in ecophysiological responses. Using morphological attributes to successfully infer macroalgal behaviour would be a remarkable advance for marine ecology, and appears attainable. Chapter three demonstrates the overwhelming importance of ecological context in altering the predictions of theory. Specifically, we demonstrate that regional species pools have reduced influence on local richness at small local scales, within interactive groups of species, and in higher intertidal zones. We conclude with a synthesis of how ecological competition, abiotic stress, and positive interactions may act in concert to influence local richness. Chapter four analytically investigates the role of diversity in changing how ecosystems function.I argue that all effects of diversity must act through species traits, and that the current debate regarding the influence of species richnessperseversus species traits is misguided. Instead, I propose a focus on the roles of the presence of, versus interactions between, traits.I provide empirical evidence that five tidepool communities each containing five species have a higher average photosynthetic rate than the same total biomass of each of the five species arranged into five monocultures, This mechanism, detected in photosynthetic rate (one of the most fundamental ecological functions), should be common to ecosystems other than marine intertidal pools. Finally, chapter five concludes with a recap of the key results from these studies, and a look to the future. © Copyright by Roland B. Russell April 14, 2005 All Rights Reserved Biodiversity: Illustrations of Some Concepts, Causes, and Consequences. by Roland B. Russell A DISSERTATION Submitted to Oregon State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy Presented on April 14, 2005 Commencement June 2005 Doctor of Philosophy dissertation of Roland B. Russell presented on April 14, 2005. APP Redacted for Privacy Co-Major professor, representing Redacted for Privacy Co-Mjö profe,sor, representing Zoology Redacted for Privacy the Redacted for Privacy Deãh of th dcte School I understand that my dissertation will become part of the permanent collection of Oregon State University libraries. My signature authorizes release of my dissertation to any readerupon request. Redacted for Privacy Roland B. Russell, Author ACKNOWLEDGEMENTS Clichéd though it may appear, I would not have completed this dissertation if itwere not for the friends, family, and colleagues that have kept me afloat. My deepest and most sincere thanks, to all of you. The challenge of translating my gratitude into words on paper is overwhelming.I am aware that I have omitted people who have been important, and that I have not adequately acknowledged the depth of what these people have done for me. With those caveats explicit, onward. For their sage intellectual guidance I especially thank Gary Allison, Francis Chan, Anne Guerry, Josh Lawler, and Dov Sax. Gary, your calm, direct, and thorough ability to synthesize is something I strive for. I'm glad that we overlapped at least for a short while, and I hopewe do so again.It's always a challenge to keep pace with Francis; I'm glad that you're willing to entertain me even when I can't quite keep up.I don't think that I've met anyone with the same aptitude for distillation and communication of information and ideas as you, Anne; we need more people who can fill such a need in this odd world. And Josh, in addition to your broad thoughts, your capacity to do, and to dedicatedly act upon your convictions constantly impresses me. You are another good model. Dov, your incessant contemplation about lifein a real, complex, and whole senseis wonderful, and a pleasure to have had the opportunity to share. To all of you five, as well as all the others, you kept the whole game interesting, which was a necessity. Thank you. For their help, which I would have been better off to have utilized more often, I sincerely thank my committee members. Jane Lubchenco, Peter McEvoy, Bruce Menge, Phil Rossignol, and Dan Schafer; you make a pretty amazing team. Dave Schiel and Kathy Moore took on (orwere, perhaps, involuntarily subjected to!) the role of committee members, yet without the formalities. Thanks to all of you for feeling like I was worth putting some time intoI appreciate it more than you probably know. Your offers of time and energy were gracious and productive. Thank you. I would especially like to thank Bruce and Jane for their constant support. Bruce, it amazesme that you door is always open and you still manage to accomplish as much as you do. Your dedication to your work is an inspiration, and your openness to give time to those of us who need it is remarkable. Even under duress (a rarity, it seems), you still manage to make the time to help all of us who need it. Thank you. Jane, the density of our conversations always impresses me. Few people have the ability to so quickly pick up a topic and return such insightful and novel perspectives.I thank you for that.It has also been a pleasure to learn from you how the rest of this scientific process works, out in the world beyond academia and into the policy, political, and public arenas.I appreciate the insights you've provided immensely.It has been a treat to spend time with the two of you. Thanks. I would also like to thank those people whom I have the deepest respect for due to their phenomenal ability to make some sense of the complexity and beauty of the world. G. E. Hutchinson seems like a truly remarkable individual, and the fact that he seems to have already written about most of what we're still working on in ecology is worth some thought.I wish he were still around. Kathy Dean-Moore, I thank you for your remarkable abilities as a wordsmith, as well as for your encouragement and teaching about care. As with Albert Schweitzer's 'reverence for life',I think that you have discovered a desperate need in the world, and I'm pleased that it is you who is satiating that need. It's a pleasure to have gotten to know youa little, and has been a memorable and lasting experience.I look forward to some unknown future projects. The grad students in our lab, and in our department, have provided plenty of interesting discussions, stimulating thoughts, and good times.I won't list you all, but you know who you are. Thanks. Likewise, the Zoology departmental staff has made this a pleasant place to work. Thanks for your dedication, and all your help carrying me through the things that I didn't understand. My New Zealand friends have been a fantastic source of entertainment, camaraderie, and enjoyable science.Toall ofyou,from Jack van Berkel, and Wayne, who sorted out the right balance of work and tea-time to keep the lab functioning productively, to Robyn, Shazza, Schiel, Dave, Liv, Stacie, Spencer, Glen, Michelle, Nathan, Mark, Katie, Curt, and everyone else who made the living so good, thanks. Kaikoura was (and is) one of the best places to work that I can imagine, both due to the idyllic place, and the stellar people. You've made it a blissful place to be, and my memories are wonderful. Perhaps most importantly, I thank those people who were my safety net through all of this; my friends and family who certainly provided to fuel to keep me going. Spencer Wood, I've always enjoyed your company; the month in Alaska was an unforgettable trip that I doubt I'll ever forget. I know that there are very few people whom I would have had such a wonderful time there as I III did. Constant wind, frozen digits, and nearly incessant rain; I would do it again with you any time (with a little mutual convincing, at least). Karen and Brock McLeod, you have become sincere friends; thanks for your honesty and your friendship. They are both invaluable. Stacie Lilley, I admire your spirit, and self-righteousness. Although we maybe didn't quite get our lives planned out as accurately as one could wish for over coffee and/or hot cocoa at Maxton's, we got close enough. Stay close. And Melissa Foleythanks for being who you are, dedication, soul, stubbornness, and all. Hopefully we can continue to have our occasional vacations to play in the snow or run around in the mountains. The times are always worthwhile. Heather Leslie was another role-model for me. Your ability to balance so many facets of life is impressive, and a good thing to strive for. And Jeremy, I'm pleased that we might have some more time to have fun togetherthey've been great times so far.