RESEARCH ON MARINE COASTAL IMPACTS TO PROMOTE ECOSYSTEM-BASED MANAGEMENT: NONNATIVE SPECIES IN NORTHEAST PACIFIC ESTUARIES by Megan Elizabeth Mach B.Sc., The University of Washington, 2005 M.S., Boston University, 2007 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE STUDIES (Resource Management and Environmental Studies) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) August 2012 © Megan Elizabeth Mach, 2012 Abstract Ecosystem-based management (EBM) offers a holistic evaluation of tradeoffs between human activities, but this offer rests upon a foundation of science. In this thesis, I assessed and advanced the knowledge-base for EBM in five ways, focusing on nonnative species in estuarine ecosystems. In Chapter 2, I tested for the comprehensiveness of research that connects the impacts of anthropogenic activities to changes in ecosystem service production, employing a literature review of estuarine ecosystems. Research on these connections virtually never included the relationship of activities to ecosystem services production, presenting an impressive gap in research for evaluating tradeoffs using EBM. I addressed the sufficiency of existing information regarding nonnative species in eelgrass beds in Chapter 3. I tested the relationship of nonnative species in British Columbia’s (BC) eelgrass beds with arrival pathways and environmental selection factors. There were few (12) nonnatives in BC’s eelgrass; all associated most commonly with aquaculture facilities and warm temperatures. Existing reports included the majority of nonnatives: only one species, the bamboo worm Clymenella torquata, represented a new record, as I described in Chapter 4. Impacts of nonnatives are difficult to limit after invasion. In Chapter 5, I developed an approach for characterizing the potential economic impacts of nonnatives. I focused on European green crab, a nonnative species that has not yet arrived in Puget Sound, Washington. At a range of invasion densities and increasing calorie diets, I calculated a value-at-risk to shellfish harvest ranging from $1.6 - $41 million USD. Such calculations can aid in preparation for impending invasion by motivating prevention and mitigation efforts. Nonnative management is often based on the available understanding of the impacts on native species. In Chapter 6, I assessed available research on the impact of nonnative seagrass, Zostera japonica, in northeast Pacific estuaries. My results suggested existing studies that quantitatively test Z. japonica impacts are insufficient to comprehensively assess the effects of this invasion. My dissertation research highlights the need for research to determine the ecosystem role of nonnatives in their invaded range through analysis of quantitative studies across broad scales. ii Preface With the exception of Chapters 1 and 7, all chapters were originally prepared as stand- alone, peer-reviewed publications. I am the senior author and took primary responsibility for the development of research questions, research design and methods, analysis and writing of all co-authored chapters. Details of co-authorship for chapters 2 to 6 are outlined below. Chapter 2. Development of this chapter stemmed from the literature review I completed for my comprehensive exam. My advisor, Dr. Kai Chan contributed to this chapter through the development of ideas and research questions. My other co-author, Dr. Rebecca Martone was key at implementing structure and testing hypotheses. Both co- authors contributed edits and comments to the manuscript. Chapter 3. The overarching question in this chapter “what nonnative species are present in British Columbia’s ports?” was developed by my funding agency, the Canadian Aquatic Invasive Species Network. Beyond this I developed all research questions and sampling methods with the support of Dr. Colin Levings. I analyzed data and wrote the manuscript with detailed editing and comments from Dr. Levings and Dr. Kai Chan. Chapter 4. Research question development, sampling methods and species identification originated from Chapter 3. In addition, my co-author, Dr. P. Sean MacDonald provided sampling results from habitats in Puget Sound, Washington as well as editing and comments on the final manuscript. I collected and analyzed all additional data and personal communications with researchers and aquaculture facilities in Washington State, and drafted the text. A version of this chapter reprinted with permission from Springer. Mach ME, CD Levings, PS McDonald, and KMA Chan. 2011. An Atlantic infaunal engineer is established in the Northeast Pacific: Clymenella torquata (polychaeta: maldanidae) on the British Columbia and Washington Coasts. Biological Invasions. 14(3):503-507 iii Chapter 5. Dr. Kai Chan contributed to the initial idea and later to edits and comments on the manuscript. Dr. Robert Ahrens helped develop the model and sensitivity analysis used in this chapter. I collected all information, carried out all data management and analyses, and drafted the text. Chapter 6. Dr. Sandy Wyllie-Echeverria contributed to the development of ideas and provided extensive edits and comments on the manuscript for this chapter. Dr. Kai Chan contributed suggestions and edits on numerous drafts, broadening the impact and application of the results. I collected all information, carried out all data management and analyses, and drafted the text. iv Table of Contents Abstract .............................................................................................................................. ii Preface .............................................................................................................................. iii Table of Contents ............................................................................................................... v List of Tables ...................................................................................................................... x List of Figures ................................................................................................................... xi List of Abbreviations ..................................................................................................... xiii Acknowledgements ......................................................................................................... xiv Epigraph .......................................................................................................................... xvi Chapter 1 Introduction .................................................................................................. 1 1.1 Human reliance on coastal ecosystems .................................................................. 1 1.2 Ecosystem-based management in marine systems ................................................. 1 1.3 Estuaries at the land-sea interface .......................................................................... 2 1.4 Impacts to estuaries ................................................................................................ 4 1.5 Nonnative species in coastal ecosystems ............................................................... 6 1.6 Seagrass and nonnative impacts in British Columbia, Canada .............................. 9 1.7 Management of marine nonnative species ........................................................... 10 1.8 Thesis overview .................................................................................................... 12 Chapter 2 Research gaps in evaluating tradeoffs in ecosystem-based management14 2.1 Synopsis ................................................................................................................ 14 2.2 Introduction .......................................................................................................... 14 2.3 Methods ................................................................................................................ 21 2.4 Results .................................................................................................................. 23 2.5 Discussion ............................................................................................................. 25 v 2.5.1 Knowledge gaps for evaluating tradeoffs within EBM ................................. 25 2.5.2 Why does understanding the complete impact-pathway matter? .................. 26 2.5.3 Linking science and management to inform EBM ........................................ 28 2.5.4 Limitations to informing the impact-pathway ............................................... 29 2.5.5 Conclusions ................................................................................................... 30 Chapter 3 Nonnative species in British Columbian Zostera marina eelgrass beds arrive by aquaculture and stay for the mild climate .................................................... 32 3.1 Synopsis ................................................................................................................ 32 3.2 Introduction .......................................................................................................... 32 3.3 Methods ................................................................................................................ 36 3.3.1 Field sampling ............................................................................................... 38 3.3.2 Vector and environmental data .....................................................................