Biodiversity and ecosystem processes in an experimental island system Dissertation to obtain the Dr. sc. agr. In the Ph. D. Program for Agricultural Sciences in Göttingen (PAG) At the Faculty of Agricultural Sciences, Georg-August-University Göttingen, Germany Presented by Hagen Andert Born in Görlitz (Germany) Göttingen, September 2017 D 7 1. Referentin/Referent: Prof. Dr. Teja Tscharntke 2. Korreferentin/Korreferent: Prof. Dr. Christoph Scherber Tag der mündlichen Prüfung: 15. November 2017 2 To Darja, Arnt and Lea, and those, who always keep the bright lantern burning in dark nights. 3 Alles Wissen und alle Vermehrung unseres Wissens endet nicht mit einem Schlusspunkt, sondern mit Fragezeichen. [All knowledge and all multiplication of our knowledge does not end with a final point, but with question marks.] Hermann Hesse (1877-1962) 4 Contents CHAPTER 1: .............................................................................................................................. 7 General Introduction .................................................................................................................. 7 GENERAL INTRODUCTION .......................................................................................... 8 STUDY REGION AND EXPERIMENTAL ISLAND SYSTEM ..................................... 9 The German barrier island Spiekeroog .................................................................................. 9 Experimental Islands – the BEFmate project ....................................................................... 11 Research Objectives ............................................................................................................. 14 Chapter Outline .................................................................................................................... 14 References ............................................................................................................................ 16 CHAPTER 2: ............................................................................................................................ 19 A barrier island perspective on species-area-relationships ...................................................... 19 Abstract ............................................................................................................................ 20 Introduction ...................................................................................................................... 21 Material and Methods ....................................................................................................... 22 Study area ............................................................................................................................. 22 Island physiognomy ............................................................................................................. 23 Plant and animal biodiversity data ....................................................................................... 24 Statistical Analyses .............................................................................................................. 24 Results .................................................................................................................................. 27 Discussion ............................................................................................................................ 28 References ............................................................................................................................ 31 SUPPORTING INFORMATION ........................................................................................ 35 CHAPTER 3: ............................................................................................................................ 51 Colonization and taxon shift in an experimental island system ............................................... 51 Abstract ............................................................................................................................ 52 Introduction ...................................................................................................................... 53 Material and Methods ....................................................................................................... 54 Study area ............................................................................................................................. 54 Experimental islands and sampling design .......................................................................... 54 Arthropod sampling .............................................................................................................. 54 Statistical Analyses .............................................................................................................. 56 Results .............................................................................................................................. 58 Discussion ........................................................................................................................ 61 References ........................................................................................................................ 64 Acknowledgements .......................................................................................................... 68 CHAPTER 4: ............................................................................................................................ 69 Diversity of decomposing flies and carcass decay in experimental salt-marsh islands of the North Sea, Germany ................................................................................................................. 69 Abstract ............................................................................................................................ 70 Introduction ...................................................................................................................... 71 Material and Methods ....................................................................................................... 72 Study area ............................................................................................................................. 72 Experimental Design ............................................................................................................ 73 Soil arthropod extraction ...................................................................................................... 76 Animal identification ............................................................................................................ 76 5 Statistical Analyses .............................................................................................................. 76 Results .............................................................................................................................. 78 Discussion ........................................................................................................................ 84 References ........................................................................................................................ 87 SUPPORTING INFORMATION .................................................................................... 92 1. DNA extraction .................................................................................................................... 93 2. PCR ...................................................................................................................................... 94 3. Sequencing ........................................................................................................................... 95 APPENDIX .............................................................................................................................. 99 A1 – Complete R-Code for Chapter 4 .................................................................................. 99 THESIS SUMMARY ............................................................................................................. 114 ZUSAMMENFASSUNG ....................................................................................................... 117 PUBLICATIONS AND SCIENTIFIC TALKS ..................................................................... 121 PUBLICATIONS ............................................................................................................... 121 CONFERENCE CONTRIBUTIONS AND SCIENTIFIC TALKS .................................. 121 CURRICULUM VITAE ........................................................................................................ 123 ACKNOWLEDGEMENTS ................................................................................................... 125 THESIS DECLERATIONS ................................................................................................... 127 Decleration of the author’s own contribution to manuscripts with multiple authors ......... 127 Declaration plagiarism ....................................................................................................... 127 6 CHAPTER 1: General Introduction 7 GENERAL INTRODUCTION Island systems have become one of the most important model systems in ecology for the last decades (Losos and Ricklefs, 2010, MacArthur and Wilson, 1967). Their discrete and isolated nature make islands a useful tool for ecological and evolutionary studies (Whittaker and Fernández-Palacios, 2007) and therefore