Geographisches Institut der Universität Bonn BIOGEOMORPHIC DYNAMICS IN THE TURTMANN GLACIER FOREFIELD, SWITZERLAND Dissertation zur Erlangung des Doktorgrades (Dr. rer. nat.) der Mathematisch-Naturwissenschaftlichen Fakultät der Rheinischen Friedrich-Wilhelms-Universität Bonn vorgelegt von JANA EICHEL aus Volkmarsen Bonn, 2016 Angefertigt mit Genehmigung der Mathematisch-Naturwissenschaftlichen Fakultät der Rheinischen Friedrich-Wilhelms-Universität Bonn 1. Gutachter: Prof. Dr. Richard Dikau 2. Gutachter: Prof. Dr. Sebastian Schmidtlein Tag der Promotion: 20.12.2016 Erscheinungsjahr: 2017 ACKNOWLEDGEMENTS According to hierarchy theory, phenomena in a focal level, such as this thesis, cannot be understood without considering their higher level constraints and lower level components and explanations. For this thesis, higher level constraints were set by Prof. Dr. Richard Dikau, Prof. Dr. Sebastian Schmidtlein and Dov Corenblit, for which I am very grateful. Richard Dikau not only introduced me to biogeomorphology, systems and hierarchy theory, the main foundations of this thesis, but also taught me how to think critically, read papers and landscapes and teach students. Sebastian Schmidtlein introduced me to the wonderful R Software, supported my interest in vegetation science and gave valuable ecologic and methodical advice. At first through his inspiring papers and later in person, Dov Corenblit provided many of the concepts and ideas followed up in this thesis and transferred the joy of biogeomorphology. In the lower level, many small components made this thesis possible. Research needs funding, infrastructure and supporting colleagues. Funding was provided mainly by the German Research Foundation (DFG), but also by many other small grants and stipends, and is highly appreciated. Important infrastructure and services were supplied by D. Weihrauch and C. Kurth (laboratory), G. Storbeck and S. Zöldi (cartography) and T. Dobrzeniecki and N. Grötsch (IT) at the Department of Geography and by Ingeborg Wieland (elementary analysis) at the INRES - Division Soil Sciences (all University of Bonn). Great colleagues brightened work, but also enlightened my free time – thanks to the Geomorph Chicks! A great thanks also goes to Rita Müller-Geiger for managing administrative duties, to my student assistants Nikola-Schulte-Kellinghaus and Andreas Ewald for excellent support and to all other field helpers who made the time-consuming data acquisition possible. Further thanks go to the colleagues at GEOLAB (Clermont-Ferrand) for stimulating biogeomorphic discussions and excursions during my research stay and to the Vegetation Science and Biogeography Research Group in Karlsruhe for welcoming me when I needed new (scientific) air to breath. For a great and rewarding cooperation on a non-moving solifluction lobe, I thank ‘the Geodesists’: Lasse Klingbeil, Markus Wieland and Christian Eling. Furthermore, I thank Bodo M. Möseler for advice on permanent plot surveying and regular interesting ecological conversations. In the Turtmann valley, infrastructure, support, and social life was provided by Familie Berckum. Numerous shared raclettes and barbeques (special thanks to Metzger Meyer!) made returning to Oberems every summer a great pleasure. As a counterbalance, successful research requires a fulfilling private life. For me, this was provided by Doro48 and ‘Anhang’ and all other friends, especially Anna and Noah and Louisa and Leo, who always brought me back into real life. Some colleagues also became important friends. Thanks to Borbála Hortobágyi for an awesome time in and around Clermont-Ferrand and to Nele Meyer not only for soil sampling but numerous wonderful outdoor adventures and Sushi- Komas. Last, but certainly not least, I thank my family, Joachim and Heidrun Eichel and Lea and Lasse Spangenberg, who provided continuous support throughout my studies (maybe not that long for Lasse), kept me grounded whenever I was in need and provided substantial input: Large rocks, small plants... Yet, the strongest interactions shaping this thesis occurred in the focal level. Thanks to Karoline Meßenzehl for sharing the office, field work, teaching, conferences, geomorphic and other discussions, holidays, shopping, wine, sushi, hipster food and so many other things with me in the last three and a half years – it was simply great! And finally, the biggest thanks goes to Dr. Daniel Draebing, the hard rock researcher who developed a sudden interest in plants and supported me in every possible way and under all conditions during thesis writing - and beyond. i CONTENTS SUMMARY ................................................................................................................................... I ZUSAMMENFASSUNG ............................................................................................................... IV LIST OF PUBLICATIONS ........................................................................................................... VIII LIST OF FIGURES ....................................................................................................................... IX LIST OF TABLES ........................................................................................................................ XIII GLOSSARY ............................................................................................................................... XIV 1 INTRODUCTION AND MOTIVATION ....................................................................................... 1 2 BIOGEOMORPHOLOGY: INTEGRATING GEOMORPHIC AND VEGETATION DYNAMICS IN GLACIER FORELANDS ................................................................................................................. 5 2.1 The trajectory of biogeomorphology – where we come from ................................................................ 6 2.1.1 Joint foundations and early ideas ......................................................................................................... 6 2.1.2 Splitting up: Development after 1950 .................................................................................................. 8 2.1.3 The birth of biogeomorphology .......................................................................................................... 10 2.1.4 The development of biogeomorphology since 1988 .......................................................................... 10 2.1.5 Wind of change: towards ‘feedback biogeomorphology’ .................................................................. 15 2.2 The trajectory of biogeomorphology – where we are now .................................................................. 17 2.2.1 Feedback biogeomorphology: integrating geomorphic and vegetation dynamics ............................ 17 2.2.2 Key biogeomorphic concepts ............................................................................................................. 17 2.3 Scales in biogeomorphology ............................................................................................................... 25 2.3.1 Traditional approaches to time, space and scale in geomorphology and ecology ............................. 25 2.3.2 Hierarchy theory ................................................................................................................................. 27 2.3.3 Panarchy ............................................................................................................................................. 30 2.3.4 Scales in biogeomorphology ............................................................................................................... 33 2.4 Geomorphic dynamics in glacier forelands .......................................................................................... 35 2.4.1 Paraglacial adjustment of glacier forelands ....................................................................................... 35 2.4.2 Paraglacial processes on lateral moraine slopes ................................................................................ 37 2.4.3 Process and landform succession on lateral moraine slopes ............................................................. 39 2.5 Vegetation succession and biogeomorphic interactions in glacier forelands ........................................ 42 2.5.1 Abstract .............................................................................................................................................. 43 2.5.2 Introduction ........................................................................................................................................ 43 2.5.3 Vegetation establishment and succession ......................................................................................... 44 2.5.4 Vegetation succession models ........................................................................................................... 44 2.5.5 Primary vegetation succession in glacier forelands ............................................................................ 48 2.5.6 What disrupts the simple successional sequence? ............................................................................ 51 2.5.7 The role of disturbances for vegetation succession in glacier forelands ............................................ 52 2.5.8 Biogeomorphic interactions in glacier forelands ................................................................................ 56 2.5.9 Case study: Biogeomorphic dynamics on lateral moraine slopes in the Turtmann