Comparison Between Multiple-Channel and Single-Channel Stream Sections — Hydromorphology and Benthic Macroinvertebrates
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Comparison between Multiple-channel and Single-channel Stream Sections — Hydromorphology and Benthic Macroinvertebrates Inaugural-Dissertation zur Erlangung des Doktorgrades Dr. rer. nat. des Fachbereichs Biologie und Geographie an der Universität Duisburg-Essen vorgelegt von Sonja Charlotte Jähnig geboren in Karlsruhe März 2007 Die der vorliegenden Arbeit zugrunde liegenden Experimente wurden am Institut für Ökolo- gie in der Abteilung Angewandte Zoologie / Hydrobiologie der Universität Duisburg-Essen durchgeführt. 1. Gutachter: PD Dr. Daniel Hering (Universität Duisburg-Essen) 2. Gutachter: Prof. Dr. Klement Tockner (ETH Zürich) 3. Gutachter: Prof. Dr. Bernd Sures (Universität Duisburg-Essen) Vorsitzende des Prüfungsausschusses: Prof. Dr. Angela Sandmann (Universität Duisburg-Essen) Tag der mündlichen Prüfung: 17. Juli 2007 zukunftmachen Acknowledgements The completion of this thesis was only possible with the input and help of many many persons: First, I would like to thank my supervisor PD Dr. Daniel Hering for the opportunity to carry out this dissertation, for his support, stimulating discussions, and critical comments on the text. I am particularly grateful to Armin Lorenz for tireless discussion, statistical advice, exchange of ideas, and his infinite improvements on the entire manuscript. My colleagues of the Hydrobiology working group are thanked for the lighthearted working atmo- sphere combined with mutual support and fruitful discussion. Special thanks go to Alexandra Haidekker, for a CANOCO crash course and comments on the summary in English and German, and special thanks also to Jochem Kail for his comments and suggestions on Chapter 2. For their assistance throughout many days in the field, with inputing 13000 rows of data, sorting 199 macroinvertebtrate samples and with the corresponding identification of 48,847 macroinver- tebrate specimens, and for the GIS implementation, I gratefully acknowledge the dedicated help of: Katja Birke, Mathias Frost, Daniel Göbel, Jörn Gutzeit, Kathrin Januschke, Jörg Kaminski, San- dra Kramm, Thomas Korte, Armin Lorenz, Gudrun Mertschenk, Birgit Mückenheim, Peter Rolauffs and Marta Wenikajtys. Special thanks go to Travis Flath, the first DAAD-RISE scholar to work with the Hydrobiology work group for three months in 2005: he set the highest standards in terms of working attitude, sup- port and good spirit in the field, in the lab, with the data and finally with many linguistic corrections in this thesis. I am deeply indebted to Dr. Rainer Lorenz who devised and designed the 'virtual flow macro' in MS Excel and was helpful with advice and ideas on Chapter 2. Steffen Pauls is thanked for comments and correction on the introduction and abstracts. Sandra Kramm, thank you for your help with the taxa lists, the German short version, sunshine and a poem every now and then. Astrid Schmidt-Kloiber and Wolfram Graf are thanked for comments on the German short version. I am grateful to several authorities for providing information and data, particularly to Herbert Diehl from the Hesse State Environmental Agency in Giessen for various types of information on the Lahn sites, and the State Environmental Agencies in Cologne, Siegen and Trier for providing discharge data. Most important, I am grateful for having received funds for this thesis from the PhD-scholarship programme of the Foundation of German Business (SDW). Besides inspiration from European col- leagues, cash for travel, helping hands, and conference participation was provided through the EU project Euro-Limpacs (GOCE-CT-2003-505540). Table of Contents List of Figures..................................................................................................................... VII List of Tables.................................................................................................................... VIII General Introduction................................................................................................... 10 Glossary and Abbreviations......................................................................................... 15 1 Hydromorphological Diversity in Multiple-channel Sections.................................... 18 1.1 Abstract...............................................................................................................18 1.2 Introduction.........................................................................................................19 1.3 Material and Methods............................................................................................20 1.3.1 Study sites....................................................................................................20 1.3.2 Hydromorphological measurements................................................................24 1.3.3 Data analyses................................................................................................24 1.4 Results.................................................................................................................25 1.4.1 Macro-scale...................................................................................................25 1.4.2 Meso-scale....................................................................................................26 1.4.3 Micro-scale....................................................................................................27 1.4.4 Correlation of metrics.....................................................................................30 1.5 Discussion............................................................................................................31 1.5.1 Metric response to increased hydromorphological diversity...............................31 1.5.2 Effects from multiple-channel origin................................................................32 1.5.3 Suitability of metrics for assessing hydromorphological diversity.......................34 1.5.4 Conclusions and implications..........................................................................35 2 Multiple-channel Sections Revisited: Quantifying Annual Changes......................... 36 2.1 Abstract...............................................................................................................36 2.2 Introduction.........................................................................................................37 2.3 Material and Methods............................................................................................39 2.3.1 Study sites....................................................................................................39 2.3.2 Hydromorphological measurements................................................................42 2.3.3 Data analyses: Differences within years.......................................................... 44 2.3.4 Data analyses: Annual changes......................................................................44 2.4 Results.................................................................................................................48 2.4.1 Hydromorphological differences within years...................................................48 2.4.2 Annual changes of hydromorphology..............................................................50 2.5 Discussion............................................................................................................53 2.5.1 Hydromorphological differences within years...................................................53 2.5.2 Annual changes of hydromorphology..............................................................54 2.5.3 Annual changes in restored and natural multiple-channel sections.................... 55 2.5.4 Conclusion and implications............................................................................56 Table of Contents VI 3 Substrate-specific Macroinvertebrate Communities in Multiple-channel Sections.. 57 3.1 Abstract...............................................................................................................57 3.2 Introduction.........................................................................................................58 3.3 Material and Methods............................................................................................59 3.3.1 Study sites....................................................................................................59 3.3.2 Hydromorphological measurements and analyses............................................ 60 3.3.3 Macroinvertebrate sampling........................................................................... 60 3.3.4 Macroinvertebrate data analyses.....................................................................62 3.4 Results.................................................................................................................63 3.4.1 Hydromorphological diversity..........................................................................63 3.4.2 Overview of macroinvertebrates communities..................................................64 3.4.3 Substrate-specific communities.......................................................................64 3.4.4 Substrate-specific communities at single- and multiple-channel sections........... 66 3.4.5 Nestedness...................................................................................................69 3.5 Discussion............................................................................................................70 3.5.1 Hydromorphological diversity..........................................................................70