INVASIVE SPECIES IN AQUATIC SYSTEMS: POPULATION, COMMUNITY, FOOD WEB AND LANDSCAPE PERSPECTIVES. by NORMAN MERCADO – SILVA A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Zoology) At the UNIVERSITY OF WISCONSIN - MADISON 2005 i Table of Contents Abstract…………………………………………………………………………………………ii Acknowledgements…………………………………………………………………………….v Chapter 1……………………………………………………………………………………….1 THESIS INTRODUCTION Chapter II……………………………………………………………………………………....10 WALLEYE RECRUITMENT DECLINE AS A CONSEQUENCE OF RAINBOW SMELT INVASIONS IN WISCONSIN LAKES Chapter III………………………………………………………………………………………47 LONG-TERM CHANGES IN THE FISH ASSEMBLAGE OF THE LAJA RIVER, GUANAJUATO, CENTRAL MEXICO. Chapter IV………………………………………………………………………………………77 FOOD WEB STRUCTURE OF AN IMPACTED SEMI-DESERTIC FRESHWATER SYSTEM IN MEXICO’S CENTRAL PLATEAU Chapter V………………………………………………………………………………………119 FORECASTING THE SPREAD OF INVASIVE RAINBOW SMELT (OSMERUS MORDAX) IN THE LAURENTIAN GREAT LAKES REGION OF NORTH AMERICA ii ABSTRACT INVASIVE SPECIES IN AQUATIC SYSTEMS: POPULATION, COMMUNITY, FOOD WEB AND LANDSCAPE PERSPECTIVES. NORMAN MERCADO-SILVA Under the supervision of Professor Jake Vander Zanden At the University of Wisconsin - Madison The introduction and establishment of invasive species is one of the major causes of changes in the composition, structure, function and viability of freshwater ecosystems. Invasive species have impacts at different levels of organization ranging from genetic (e.g., hybridization and introgression) to ecosystem (e.g., nutrient flux alterations and disturbance regime alteration). At each level, the consequences of the invader-native interaction pose important scientific and management questions. I conducted four separate studies addressing exotic species in two geographic areas, the Laja River in Central Mexico, and temperate lakes in the Great Lakes region. Through these studies, I explored the interactions of exotics with native species from the perspectives of populations, communities, food web interactions and their expansion across the landscape. At the population level, I studied how rainbow smelt (Osmerus mordax) invasion can affect walleye (Sander vitreus) populations by reducing the recruitment of young-of- the-year fishes to the adult population in invaded lakes in Wisconsin. This process has had significant repercussions on invaded lakes, and could have serious consequences for walleye, one of the iii most important fisheries in the state, if smelt continue to expand. The potential of individual lakes for smelt colonization was also investigated, resulting in the identification of a subset of 188 lakes where management and invasion prevention efforts should be prioritized. From a community perspective, through a study of the long term changes of the fish assemblage of the Rio Laja, I identified the changes in fish communities resulting from a mix of human impacts. Significant declines in the number of benthivore, carnivore, and sensitive species, and important increases in the number of exotic and tolerant species have occurred in this system since the 1960’s, resulting in a present-day community of fishes where exotics are common and few sensitive native species remain. A stable isotope-based food web analysis of the fish communities in the Laja was carried out to understand the historical and present-day food web interactions at a series of sites in the watershed. This study revealed how reservoirs alter the basal resources that fish communities depend on, and how invasive species now overlap with native species in terms of resource use. Changes observed in the Laja from the perspective of communities and food webs have important implications for understanding how fish communities in other rivers in central Mexico, for which long-term data do not exist, have changed or could change if environmental deterioration continues. From a landscape perspective, using morphological, physical-chemical and biological information from Maine (US) lakes where rainbow smelt are native, I developed a model to predict which individual lakes in the Great Lakes region would be suitable for smelt invasion. The model was successful in predicting smelt presence/absence in Maine and was used to make broad scale predictions of smelt distribution for over 8000 lakes in Ontario and Wisconsin. The analysis identified 4447 and 553 lakes in Ontario and Wisconsin respectively, suitable for smelt iv invasion. These suitable lakes are where preventive steps should be taken against the impact of this invasive species. Approved -------------------------- Jake Vander Zanden v ACKNOWLEDGEMENTS This thesis is the product of efforts and contributions of many people who have supported me throughout my life. I will start by thanking my two major professors, Jake Vander Zanden and John Lyons, for all the work they put into expanding and reshaping my ideas. I thank Jake for the friendly attitude he always had when I showed up upon his door for advice, for his infinite patience, and for understanding and expanding my limits of thought. I believe academic advising is important in shaping a life - Jake’s good at it. I am grateful for his constant push for improvement and for making me aim high with my work. It has been great to have such a great teacher, collaborator, friend, and text editor (if it were not for Jake this thesis would be twice as long – thanks for the Spanish → English word reduction). John Lyons has been a most important person in shaping me into the biologist I am today. I thank John for initiating and supporting my temporary importation to the US, and all my work in Mexican systems. John is 1.5 academic fathers to me (½ for my BS, ½ for my MS and now, I’d say ½ for my PhD). It has been a great honor to have him as an advisor and colleague. I have benefited enormously from his expertise and knowledge, and to a certain degree from the vast ‘John Lyon’s Fund for Graduate Students from the Third World’. Thank you Juan for all these years of collaboration and guidance. A good part of my learning about my country I owe to you. Jim Kitchell, Emily Stanley, Timothy Moermond and Erick Nordheim always offered good advice for the completion of my degree. I have learned much from their example. In addition to their excellent academic advice, their performances as teachers, advisors, and as graduate student and research institute managers are impressive examples to follow. Thank you vi all committee members for the guidance. Many other faculty members at UW and elsewhere, like Steve Carpenter and Tom Hrabik were key in the completion of my studies at the CFL, and I thank their advice and support in this process. I am thankful for the opportunity to learn from and collaborate with graduate students and post-docs (past and present) at the Center for Limnology and the Department of Zoology. I have learned much from colleagues and friends like Julian Olden, Brian Weigel, and Kyle Piller. It is good to know collaborations are ongoing. Cailin Orr and Greg Sass were two with whom I shared a good portion of my time at the CFL. They went first in this PhD process, were always a model to me, and above all, were great friends: Thanks! Olaf Jensen, Amy Kamarainen, Katrina Butkas and Theo Willis always made coming to 126 CFL enjoyable. I thank their encouragement and advice. Katie Hein, Matt Diebel, Chris Solomon, Jeff Maxted, David Gilroy, Stephanie Schmidt, Katrina Butkas, and Zeb Hogan sailed with me in the Vander Zanden boat – it was a fun and enriching ride. Matt Helmus was an important colleague in exploring Mexican waters and I am glad he got interested in continuing work there. Many other friends and colleagues helped in various stages of these projects, they include - but are not limited to: Isaac Kaplan, Pieter Johnson, Brian Roth, Jeff Jorgensen, Caitlin Gille, Hem Nalini Morzaria, Chad Harvey, Elena Bennet, Matt Van de Bogert, Paul Hanson, Kristy Rogers, Stacy Lishka, Oscar Pérez, Genkai Kato, and Ken Forshay. I also want to thank Willaim Fetzer, Gretchen Anderson, Ellen Feingold, and Dan Cobian for the good times procesing samples or catching fishes for LTER. I am thankful for all the efforts made by the staff at the CFL, the Dept. of Zoology and the Trout Lake station. Pam Montz, Dave Balsiger, Barbara Benson, Ted Cummings, Pam Fashingbauer, Dave Harring, Denise Karns, Tim Kratz, Marilyn Larsen, Tim Meinke, Anne vii Murphy-Lom, John Verhs, Georgia Wagner, Carol Schraufnagel, Mike Pecore, Jim Rusak, Michelle Woodford and Scott Van Egeren were important in keeping this career going. I am sure I am missing someone in all these acknowledgements right now. You will come up in my memories I am sure, and I thank you as well. I want to thank the Consejo Nacional de Ciencia y Tecnología (CONACyT) in Mexico, the North Temperate Lakes Long Term Ecological Research Project and the Department of Zoology for their support at different stages of my graduate studies. The binational nature of this thesis requires my thanking many colleagues and friends back home. Please change brain settings. Quiero agradecer el apoyo durante todos estos años, de Guillermo Salgado Maldonado, mi director de tesis en mi alma mater, la UNAM. En especial quiero agradecerle el haberme puesto en ruta – ya llegué, y acabo de comenzar. Edmundo Díaz- Pardo ha sido un profesor y colega ejemplar, muchas gracias por el apoyo. Eduardo Soto-Galera, Martina Medina, Omar Domiguez, Luis Zambrano, y Salvador Contreras-Balderas han sido maestros y colegas