The Assessment of Current Biogeographic Patterns of Coral Reef
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THE ASSESSMENT OF CURRENT BIOGEOGRAPHIC PATTERNS OF CORAL REEF FISHES IN THE RED SEA BY INCORPORATING THEIR EVOLUTIONARY AND ECOLOGICAL BACKGROUND Dissertation by Vanessa S. N. Robitzch Sierra In Partial Fulfillment of the Requirements For the Degree of Doctor of Philosophy King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia ©March, 2017 Vanessa S. N. Robitzch Sierra All rights reserved 2 EXAMINATION COMMITTEE PAGE The dissertation of Vanessa S. N. Robitzch Sierra is approved by the examination committee. Committee Chairperson: Dr. Michael Berumen Committee Members: Dr. Christian Voolstra, Dr. Timothy Ravasi, Dr. Giacomo Bernardi 3 ABSTRACT THE ASSESSMENT OF CURRENT BIOGEOGRAPHIC PATTERNS OF CORAL REEF FISHES IN THE RED SEA BY INCORPORATING THEIR EVOLUTIONARY AND ECOLOGICAL BACKGROUND Vanessa S. N. Robitzch Sierra The exceptional environment of the Red Sea has lead to high rates of endemism and biodiversity. Located at the periphery of the world’s coral reefs distribution, its relatively young reefs offer an ideal opportunity to study biogeography and underlying evolutionary and ecological triggers. Here, I provide baseline information on putative seasonal recruitment patterns of reef fishes along a cross shelf gradient at an inshore, mid-shelf, and shelf-edge reef in the central Saudi Arabian Red Sea. I propose a basic comparative model to resolve biogeographic patterns in endemic and cosmopolitan reef fishes. Therefore, I chose the genetically, biologically, and ecologically similar coral-dwelling damselfishes Dascyllus aruanus and D. marginatus as a model species-group. As a first step, basic information on the distribution, population structure, and genetic diversity is evaluated within and outside the Red Sea along most of their global distribution. Second, pelagic larval durations (PLDs) within the Red Sea environmental gradient are explored. For the aforementioned, PLDs of the only other Red Sea Dascyllus, D. trimaculatus, are included for a more comprehensive comparison. Third, to further assess ongoing pathways of connectivity and geneflow related to larval behavior and dispersal in Red Sea reef fishes, the genetic composition and kinship of a single recruitment 4 cohort of D. aruanus arriving together at one single reef is quantified using single nuclear polymorphisms (SNPs). Genetic diversity and relatedness of the recruits are compared to that of the standing population at the settlement reef, providing insight into putative dispersal strategies and behavior of coral reef fish larvae. As a fourth component to study traits shaping biogeography, the ecology and adaptive potential of the cosmopolitan D. aruanus is described by studying morphometric-geometrics of the body structure in relation to the stomach content and prey type from specimen along the cross-shelf of the central Red Sea and at a site outside the Red Sea, in Madagascar, and approach whether foraging strategies change depending on geographic location and environment, and if differences in diet are followed by phenotypic plasticity. Jointly, results suggest that biological responses and putative adaptive strategies are correlated with different biogeographic ranges and habitat preferences. 5 ACKNOWLEDGMENTS In dedication to the amazing uniqueness of the Red Sea. It is full of explainable exceptions to entertain you for millions of years. For the completion of this work, I thank my parents for their unconditional support, trust, love, and pride. Together with Shobhit and the rest of my family I have the strongest backbone one could ever wish for, with me, at all times. I cannot thank those people enough. With them, I felt strong, even throughout probably the most difficult stage of my life. I further thank Scott for having been a motivating, loyal, and kind companion, who showed me what hard work, endurance, discipline, and commitment really look like; four qualities without which I would not have been able to complete such an extensive work in this short period of time. It is hard to put down in words how lucky I further am in having met some of the most loving people I can call friends. I thank them very much for always being just a Skype call or text message away, no matter the time zone, geographical location, or issue. These also include my Saudi skippers, friends, and charming and protective helpers from Thuwal: Abdullah, Mohammed, Assam, Whaled, Ghazi; and Amr, Ramzi, and Haitham. It was never too hot, too early, too tiring, or too impossible to help and please me with all of their motivating energy! I am also grateful to have found a field of work, in which I can rely on colleagues and their knowledge at all times and no matter if I a stranger, student, or casual acquaintance. Among many, these include in particular two previous postdocs at KAUST and good friends, Pablo and Joey; my advisor, Dr. Michael Berumen; my former advisor, Dr. Xabier Irigoyen; my committee members: Dr. Giacomo Bernardi, Dr. Chrisitan Voolstra, and Dr. Timothy Ravasi; and the generous and enthusiastic Dr. Bruno Frédérich, Dr. Ben Victor, and Dr. David Kaplan. Last but not least, I thank Dani for giving me back the ability to perceive other wonders in life, to widen the scope of curiosities to explore and learn from, and become a finer, stronger, and more complex being. 6 TABLE OF CONTENTS TITLE PAGE ................................................................................................................................ 1 EXAMINATION COMMITTEE PAGE ...................................................................................... 2 ABSTRACT ................................................................................................................................... 3 ACKNOWLEDGMENTS ............................................................................................................. 5 TABLE OF CONTENTS .............................................................................................................. 6 LIST OF ABBREVIATIONS .................................................................................................... 14 LIST OF FIGURES .................................................................................................................... 17 LIST OF TABLES ..................................................................................................................... 20 CHAPTER I GENERAL INTRODUCTION TO THE STUDY OF BIOGEOGRAPHY............................ 21 1.1 BIOGeOGRAPHY AND BIODIVeRSITY IN MARINE eCOSYSTeMS ................................................ 24 1.1.1 Evolution and Historical Biogeography of Coral Reefs .............................. 25 1.1.2 Evolution and Historical Biogeography of Coral Reef Fishes .................. 26 1.1.3 Coral Reef Biogeographic Regions and Their Origin ................................... 28 1.2 THE RED SEA: INTeGRATING eCOLOGICAL AND HISTORICAL BIOGeOGRAPHY TO UNDERSTAND CURRENT CORAL REEF FISH DISTRIBUTIONS ............................................................. 31 1.2.1 Origin and environment ......................................................................................... 31 1.2.2 Ecological Biogeography and Connectivity ..................................................... 32 1.2.2.1 endemism and Biodiversity ................................................................................... 32 1.2.2.2 Population Genetics and Connectivity .............................................................. 34 7 1.2.2.3 Larval Dispersal and Recruitment ..................................................................... 36 1.3 DASCYLLUS ARUANUS AND D. MARGINATUS AS MODeL ORGANISMS ....................................... 39 1.3.1 Dascyllus aruanus (Linnaeus, 1758) .................................................................. 41 1.3.1.1 Biogeography and Evolution ................................................................................. 41 1.3.1.2 Ecology and Biology .................................................................................................. 42 1.3.2 Dascyllus marginatus (Rüppell, 1829) .............................................................. 44 1.3.2.1 Biogeography and Evolution ................................................................................. 44 1.3.2.2 Ecology and Biology .................................................................................................. 44 1.4 REFERENCES .................................................................................................................................... 46 CHAPTER II ANNUAL DISTRIBUTION OF RECRUITMENT OF CORAL REEF FISHES ALONG A CROSS-SHELF GRADIENT IN THE CENTRAL RED SEA ................................................ 56 2.1 INTRODUCTION ................................................................................................................................ 56 2.2 MATeRIALS AND METHODS ........................................................................................................... 65 2.2.1 Trials and First Collections ................................................................................... 65 2.2.2 experimental Design ................................................................................................. 66 2.2.3 Collection of Biological Data .................................................................................. 67 2.2.3.1 Sampling and Biomass Assessment .................................................................... 67 2.2.3.2 DNA extraction,